Move `rustllvm` into `rustc_llvm`

11 files changed, 4368 insertions, 0 deletions

diff --git a/compiler/rustc_llvm/Cargo.toml b/compiler/rustc_llvm/Cargo.toml
new file mode 100644
index 00000000000..ee83689f0a4
--- /dev/null
+++ b/compiler/rustc_llvm/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+authors = ["The Rust Project Developers"]
+name = "rustc_llvm"
+version = "0.0.0"
+edition = "2018"
+
+[features]
+static-libstdcpp = []
+emscripten = []
+
+[dependencies]
+libc = "0.2.73"
+
+[build-dependencies]
+build_helper = { path = "../../src/build_helper" }
+cc = "1.0.58"
diff --git a/compiler/rustc_llvm/build.rs b/compiler/rustc_llvm/build.rs
new file mode 100644
index 00000000000..7f1e5cf336a
--- /dev/null
+++ b/compiler/rustc_llvm/build.rs
@@ -0,0 +1,322 @@
+use std::env;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+
+use build_helper::{output, tracked_env_var_os};
+
+fn detect_llvm_link() -> (&'static str, &'static str) {
+    // Force the link mode we want, preferring static by default, but
+    // possibly overridden by `configure --enable-llvm-link-shared`.
+    if tracked_env_var_os("LLVM_LINK_SHARED").is_some() {
+        ("dylib", "--link-shared")
+    } else {
+        ("static", "--link-static")
+    }
+}
+
+fn main() {
+    if tracked_env_var_os("RUST_CHECK").is_some() {
+        // If we're just running `check`, there's no need for LLVM to be built.
+        return;
+    }
+
+    build_helper::restore_library_path();
+
+    let target = env::var("TARGET").expect("TARGET was not set");
+    let llvm_config =
+        tracked_env_var_os("LLVM_CONFIG").map(|x| Some(PathBuf::from(x))).unwrap_or_else(|| {
+            if let Some(dir) = tracked_env_var_os("CARGO_TARGET_DIR").map(PathBuf::from) {
+                let to_test = dir
+                    .parent()
+                    .unwrap()
+                    .parent()
+                    .unwrap()
+                    .join(&target)
+                    .join("llvm/bin/llvm-config");
+                if Command::new(&to_test).output().is_ok() {
+                    return Some(to_test);
+                }
+            }
+            None
+        });
+
+    if let Some(llvm_config) = &llvm_config {
+        println!("cargo:rerun-if-changed={}", llvm_config.display());
+    }
+    let llvm_config = llvm_config.unwrap_or_else(|| PathBuf::from("llvm-config"));
+
+    // Test whether we're cross-compiling LLVM. This is a pretty rare case
+    // currently where we're producing an LLVM for a different platform than
+    // what this build script is currently running on.
+    //
+    // In that case, there's no guarantee that we can actually run the target,
+    // so the build system works around this by giving us the LLVM_CONFIG for
+    // the host platform. This only really works if the host LLVM and target
+    // LLVM are compiled the same way, but for us that's typically the case.
+    //
+    // We *want* detect this cross compiling situation by asking llvm-config
+    // what its host-target is. If that's not the TARGET, then we're cross
+    // compiling. Unfortunately `llvm-config` seems either be buggy, or we're
+    // misconfiguring it, because the `i686-pc-windows-gnu` build of LLVM will
+    // report itself with a `--host-target` of `x86_64-pc-windows-gnu`. This
+    // tricks us into thinking we're doing a cross build when we aren't, so
+    // havoc ensues.
+    //
+    // In any case, if we're cross compiling, this generally just means that we
+    // can't trust all the output of llvm-config because it might be targeted
+    // for the host rather than the target. As a result a bunch of blocks below
+    // are gated on `if !is_crossed`
+    let target = env::var("TARGET").expect("TARGET was not set");
+    let host = env::var("HOST").expect("HOST was not set");
+    let is_crossed = target != host;
+
+    let mut optional_components = vec![
+        "x86",
+        "arm",
+        "aarch64",
+        "amdgpu",
+        "avr",
+        "mips",
+        "powerpc",
+        "systemz",
+        "jsbackend",
+        "webassembly",
+        "msp430",
+        "sparc",
+        "nvptx",
+        "hexagon",
+    ];
+
+    let mut version_cmd = Command::new(&llvm_config);
+    version_cmd.arg("--version");
+    let version_output = output(&mut version_cmd);
+    let mut parts = version_output.split('.').take(2).filter_map(|s| s.parse::<u32>().ok());
+    let (major, _minor) = if let (Some(major), Some(minor)) = (parts.next(), parts.next()) {
+        (major, minor)
+    } else {
+        (6, 0)
+    };
+
+    if major > 6 {
+        optional_components.push("riscv");
+    }
+
+    let required_components = &[
+        "ipo",
+        "bitreader",
+        "bitwriter",
+        "linker",
+        "asmparser",
+        "lto",
+        "coverage",
+        "instrumentation",
+    ];
+
+    let components = output(Command::new(&llvm_config).arg("--components"));
+    let mut components = components.split_whitespace().collect::<Vec<_>>();
+    components.retain(|c| optional_components.contains(c) || required_components.contains(c));
+
+    for component in required_components {
+        if !components.contains(component) {
+            panic!("require llvm component {} but wasn't found", component);
+        }
+    }
+
+    for component in components.iter() {
+        println!("cargo:rustc-cfg=llvm_component=\"{}\"", component);
+    }
+
+    if major >= 9 {
+        println!("cargo:rustc-cfg=llvm_has_msp430_asm_parser");
+    }
+
+    // Link in our own LLVM shims, compiled with the same flags as LLVM
+    let mut cmd = Command::new(&llvm_config);
+    cmd.arg("--cxxflags");
+    let cxxflags = output(&mut cmd);
+    let mut cfg = cc::Build::new();
+    cfg.warnings(false);
+    for flag in cxxflags.split_whitespace() {
+        // Ignore flags like `-m64` when we're doing a cross build
+        if is_crossed && flag.starts_with("-m") {
+            continue;
+        }
+
+        if flag.starts_with("-flto") {
+            continue;
+        }
+
+        // -Wdate-time is not supported by the netbsd cross compiler
+        if is_crossed && target.contains("netbsd") && flag.contains("date-time") {
+            continue;
+        }
+
+        // Include path contains host directory, replace it with target
+        if is_crossed && flag.starts_with("-I") {
+            cfg.flag(&flag.replace(&host, &target));
+            continue;
+        }
+
+        cfg.flag(flag);
+    }
+
+    for component in &components {
+        let mut flag = String::from("LLVM_COMPONENT_");
+        flag.push_str(&component.to_uppercase());
+        cfg.define(&flag, None);
+    }
+
+    if tracked_env_var_os("LLVM_RUSTLLVM").is_some() {
+        cfg.define("LLVM_RUSTLLVM", None);
+    }
+
+    if tracked_env_var_os("LLVM_NDEBUG").is_some() {
+        cfg.define("NDEBUG", None);
+        cfg.debug(false);
+    }
+
+    build_helper::rerun_if_changed_anything_in_dir(Path::new("llvm-wrapper"));
+    cfg.file("llvm-wrapper/PassWrapper.cpp")
+        .file("llvm-wrapper/RustWrapper.cpp")
+        .file("llvm-wrapper/ArchiveWrapper.cpp")
+        .file("llvm-wrapper/CoverageMappingWrapper.cpp")
+        .file("llvm-wrapper/Linker.cpp")
+        .cpp(true)
+        .cpp_link_stdlib(None) // we handle this below
+        .compile("llvm-wrapper");
+
+    let (llvm_kind, llvm_link_arg) = detect_llvm_link();
+
+    // Link in all LLVM libraries, if we're using the "wrong" llvm-config then
+    // we don't pick up system libs because unfortunately they're for the host
+    // of llvm-config, not the target that we're attempting to link.
+    let mut cmd = Command::new(&llvm_config);
+    cmd.arg(llvm_link_arg).arg("--libs");
+
+    if !is_crossed {
+        cmd.arg("--system-libs");
+    } else if target.contains("windows-gnu") {
+        println!("cargo:rustc-link-lib=shell32");
+        println!("cargo:rustc-link-lib=uuid");
+    } else if target.contains("netbsd") || target.contains("haiku") {
+        println!("cargo:rustc-link-lib=z");
+    }
+    cmd.args(&components);
+
+    for lib in output(&mut cmd).split_whitespace() {
+        let name = if lib.starts_with("-l") {
+            &lib[2..]
+        } else if lib.starts_with('-') {
+            &lib[1..]
+        } else if Path::new(lib).exists() {
+            // On MSVC llvm-config will print the full name to libraries, but
+            // we're only interested in the name part
+            let name = Path::new(lib).file_name().unwrap().to_str().unwrap();
+            name.trim_end_matches(".lib")
+        } else if lib.ends_with(".lib") {
+            // Some MSVC libraries just come up with `.lib` tacked on, so chop
+            // that off
+            lib.trim_end_matches(".lib")
+        } else {
+            continue;
+        };
+
+        // Don't need or want this library, but LLVM's CMake build system
+        // doesn't provide a way to disable it, so filter it here even though we
+        // may or may not have built it. We don't reference anything from this
+        // library and it otherwise may just pull in extra dependencies on
+        // libedit which we don't want
+        if name == "LLVMLineEditor" {
+            continue;
+        }
+
+        let kind = if name.starts_with("LLVM") { llvm_kind } else { "dylib" };
+        println!("cargo:rustc-link-lib={}={}", kind, name);
+    }
+
+    // LLVM ldflags
+    //
+    // If we're a cross-compile of LLVM then unfortunately we can't trust these
+    // ldflags (largely where all the LLVM libs are located). Currently just
+    // hack around this by replacing the host triple with the target and pray
+    // that those -L directories are the same!
+    let mut cmd = Command::new(&llvm_config);
+    cmd.arg(llvm_link_arg).arg("--ldflags");
+    for lib in output(&mut cmd).split_whitespace() {
+        if is_crossed {
+            if lib.starts_with("-LIBPATH:") {
+                println!("cargo:rustc-link-search=native={}", lib[9..].replace(&host, &target));
+            } else if lib.starts_with("-L") {
+                println!("cargo:rustc-link-search=native={}", lib[2..].replace(&host, &target));
+            }
+        } else if lib.starts_with("-LIBPATH:") {
+            println!("cargo:rustc-link-search=native={}", &lib[9..]);
+        } else if lib.starts_with("-l") {
+            println!("cargo:rustc-link-lib={}", &lib[2..]);
+        } else if lib.starts_with("-L") {
+            println!("cargo:rustc-link-search=native={}", &lib[2..]);
+        }
+    }
+
+    // Some LLVM linker flags (-L and -l) may be needed even when linking
+    // rustc_llvm, for example when using static libc++, we may need to
+    // manually specify the library search path and -ldl -lpthread as link
+    // dependencies.
+    let llvm_linker_flags = tracked_env_var_os("LLVM_LINKER_FLAGS");
+    if let Some(s) = llvm_linker_flags {
+        for lib in s.into_string().unwrap().split_whitespace() {
+            if lib.starts_with("-l") {
+                println!("cargo:rustc-link-lib={}", &lib[2..]);
+            } else if lib.starts_with("-L") {
+                println!("cargo:rustc-link-search=native={}", &lib[2..]);
+            }
+        }
+    }
+
+    let llvm_static_stdcpp = tracked_env_var_os("LLVM_STATIC_STDCPP");
+    let llvm_use_libcxx = tracked_env_var_os("LLVM_USE_LIBCXX");
+
+    let stdcppname = if target.contains("openbsd") {
+        if target.contains("sparc64") { "estdc++" } else { "c++" }
+    } else if target.contains("freebsd") {
+        "c++"
+    } else if target.contains("darwin") {
+        "c++"
+    } else if target.contains("netbsd") && llvm_static_stdcpp.is_some() {
+        // NetBSD uses a separate library when relocation is required
+        "stdc++_pic"
+    } else if llvm_use_libcxx.is_some() {
+        "c++"
+    } else {
+        "stdc++"
+    };
+
+    // RISC-V requires libatomic for sub-word atomic operations
+    if target.starts_with("riscv") {
+        println!("cargo:rustc-link-lib=atomic");
+    }
+
+    // C++ runtime library
+    if !target.contains("msvc") {
+        if let Some(s) = llvm_static_stdcpp {
+            assert!(!cxxflags.contains("stdlib=libc++"));
+            let path = PathBuf::from(s);
+            println!("cargo:rustc-link-search=native={}", path.parent().unwrap().display());
+            if target.contains("windows") {
+                println!("cargo:rustc-link-lib=static-nobundle={}", stdcppname);
+            } else {
+                println!("cargo:rustc-link-lib=static={}", stdcppname);
+            }
+        } else if cxxflags.contains("stdlib=libc++") {
+            println!("cargo:rustc-link-lib=c++");
+        } else {
+            println!("cargo:rustc-link-lib={}", stdcppname);
+        }
+    }
+
+    // Libstdc++ depends on pthread which Rust doesn't link on MinGW
+    // since nothing else requires it.
+    if target.contains("windows-gnu") {
+        println!("cargo:rustc-link-lib=static-nobundle=pthread");
+    }
+}
diff --git a/compiler/rustc_llvm/llvm-wrapper/.editorconfig b/compiler/rustc_llvm/llvm-wrapper/.editorconfig
new file mode 100644
index 00000000000..865cd45f708
--- /dev/null
+++ b/compiler/rustc_llvm/llvm-wrapper/.editorconfig
@@ -0,0 +1,6 @@
+[*.{h,cpp}]
+end_of_line = lf
+insert_final_newline = true
+charset = utf-8
+indent_style = space
+indent_size = 2
diff --git a/compiler/rustc_llvm/llvm-wrapper/ArchiveWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/ArchiveWrapper.cpp
new file mode 100644
index 00000000000..2797fe8df4a
--- /dev/null
+++ b/compiler/rustc_llvm/llvm-wrapper/ArchiveWrapper.cpp
@@ -0,0 +1,226 @@
+#include "LLVMWrapper.h"
+
+#include "llvm/Object/Archive.h"
+#include "llvm/Object/ArchiveWriter.h"
+#include "llvm/Support/Path.h"
+
+using namespace llvm;
+using namespace llvm::object;
+
+struct RustArchiveMember {
+  const char *Filename;
+  const char *Name;
+  Archive::Child Child;
+
+  RustArchiveMember()
+      : Filename(nullptr), Name(nullptr),
+        Child(nullptr, nullptr, nullptr)
+  {
+  }
+  ~RustArchiveMember() {}
+};
+
+struct RustArchiveIterator {
+  bool First;
+  Archive::child_iterator Cur;
+  Archive::child_iterator End;
+  std::unique_ptr<Error> Err;
+
+  RustArchiveIterator(Archive::child_iterator Cur, Archive::child_iterator End,
+      std::unique_ptr<Error> Err)
+    : First(true),
+      Cur(Cur),
+      End(End),
+      Err(std::move(Err)) {}
+};
+
+enum class LLVMRustArchiveKind {
+  GNU,
+  BSD,
+  DARWIN,
+  COFF,
+};
+
+static Archive::Kind fromRust(LLVMRustArchiveKind Kind) {
+  switch (Kind) {
+  case LLVMRustArchiveKind::GNU:
+    return Archive::K_GNU;
+  case LLVMRustArchiveKind::BSD:
+    return Archive::K_BSD;
+  case LLVMRustArchiveKind::DARWIN:
+    return Archive::K_DARWIN;
+  case LLVMRustArchiveKind::COFF:
+    return Archive::K_COFF;
+  default:
+    report_fatal_error("Bad ArchiveKind.");
+  }
+}
+
+typedef OwningBinary<Archive> *LLVMRustArchiveRef;
+typedef RustArchiveMember *LLVMRustArchiveMemberRef;
+typedef Archive::Child *LLVMRustArchiveChildRef;
+typedef Archive::Child const *LLVMRustArchiveChildConstRef;
+typedef RustArchiveIterator *LLVMRustArchiveIteratorRef;
+
+extern "C" LLVMRustArchiveRef LLVMRustOpenArchive(char *Path) {
+  ErrorOr<std::unique_ptr<MemoryBuffer>> BufOr =
+      MemoryBuffer::getFile(Path, -1, false);
+  if (!BufOr) {
+    LLVMRustSetLastError(BufOr.getError().message().c_str());
+    return nullptr;
+  }
+
+  Expected<std::unique_ptr<Archive>> ArchiveOr =
+      Archive::create(BufOr.get()->getMemBufferRef());
+
+  if (!ArchiveOr) {
+    LLVMRustSetLastError(toString(ArchiveOr.takeError()).c_str());
+    return nullptr;
+  }
+
+  OwningBinary<Archive> *Ret = new OwningBinary<Archive>(
+      std::move(ArchiveOr.get()), std::move(BufOr.get()));
+
+  return Ret;
+}
+
+extern "C" void LLVMRustDestroyArchive(LLVMRustArchiveRef RustArchive) {
+  delete RustArchive;
+}
+
+extern "C" LLVMRustArchiveIteratorRef
+LLVMRustArchiveIteratorNew(LLVMRustArchiveRef RustArchive) {
+  Archive *Archive = RustArchive->getBinary();
+#if LLVM_VERSION_GE(10, 0)
+  std::unique_ptr<Error> Err = std::make_unique<Error>(Error::success());
+#else
+  std::unique_ptr<Error> Err = llvm::make_unique<Error>(Error::success());
+#endif
+  auto Cur = Archive->child_begin(*Err);
+  if (*Err) {
+    LLVMRustSetLastError(toString(std::move(*Err)).c_str());
+    return nullptr;
+  }
+  auto End = Archive->child_end();
+  return new RustArchiveIterator(Cur, End, std::move(Err));
+}
+
+extern "C" LLVMRustArchiveChildConstRef
+LLVMRustArchiveIteratorNext(LLVMRustArchiveIteratorRef RAI) {
+  if (RAI->Cur == RAI->End)
+    return nullptr;
+
+  // Advancing the iterator validates the next child, and this can
+  // uncover an error. LLVM requires that we check all Errors,
+  // so we only advance the iterator if we actually need to fetch
+  // the next child.
+  // This means we must not advance the iterator in the *first* call,
+  // but instead advance it *before* fetching the child in all later calls.
+  if (!RAI->First) {
+    ++RAI->Cur;
+    if (*RAI->Err) {
+      LLVMRustSetLastError(toString(std::move(*RAI->Err)).c_str());
+      return nullptr;
+    }
+  } else {
+    RAI->First = false;
+  }
+
+  if (RAI->Cur == RAI->End)
+    return nullptr;
+
+  const Archive::Child &Child = *RAI->Cur.operator->();
+  Archive::Child *Ret = new Archive::Child(Child);
+
+  return Ret;
+}
+
+extern "C" void LLVMRustArchiveChildFree(LLVMRustArchiveChildRef Child) {
+  delete Child;
+}
+
+extern "C" void LLVMRustArchiveIteratorFree(LLVMRustArchiveIteratorRef RAI) {
+  delete RAI;
+}
+
+extern "C" const char *
+LLVMRustArchiveChildName(LLVMRustArchiveChildConstRef Child, size_t *Size) {
+  Expected<StringRef> NameOrErr = Child->getName();
+  if (!NameOrErr) {
+    // rustc_codegen_llvm currently doesn't use this error string, but it might be
+    // useful in the future, and in the mean time this tells LLVM that the
+    // error was not ignored and that it shouldn't abort the process.
+    LLVMRustSetLastError(toString(NameOrErr.takeError()).c_str());
+    return nullptr;
+  }
+  StringRef Name = NameOrErr.get();
+  *Size = Name.size();
+  return Name.data();
+}
+
+extern "C" const char *LLVMRustArchiveChildData(LLVMRustArchiveChildRef Child,
+                                                size_t *Size) {
+  StringRef Buf;
+  Expected<StringRef> BufOrErr = Child->getBuffer();
+  if (!BufOrErr) {
+    LLVMRustSetLastError(toString(BufOrErr.takeError()).c_str());
+    return nullptr;
+  }
+  Buf = BufOrErr.get();
+  *Size = Buf.size();
+  return Buf.data();
+}
+
+extern "C" LLVMRustArchiveMemberRef
+LLVMRustArchiveMemberNew(char *Filename, char *Name,
+                         LLVMRustArchiveChildRef Child) {
+  RustArchiveMember *Member = new RustArchiveMember;
+  Member->Filename = Filename;
+  Member->Name = Name;
+  if (Child)
+    Member->Child = *Child;
+  return Member;
+}
+
+extern "C" void LLVMRustArchiveMemberFree(LLVMRustArchiveMemberRef Member) {
+  delete Member;
+}
+
+extern "C" LLVMRustResult
+LLVMRustWriteArchive(char *Dst, size_t NumMembers,
+                     const LLVMRustArchiveMemberRef *NewMembers,
+                     bool WriteSymbtab, LLVMRustArchiveKind RustKind) {
+
+  std::vector<NewArchiveMember> Members;
+  auto Kind = fromRust(RustKind);
+
+  for (size_t I = 0; I < NumMembers; I++) {
+    auto Member = NewMembers[I];
+    assert(Member->Name);
+    if (Member->Filename) {
+      Expected<NewArchiveMember> MOrErr =
+          NewArchiveMember::getFile(Member->Filename, true);
+      if (!MOrErr) {
+        LLVMRustSetLastError(toString(MOrErr.takeError()).c_str());
+        return LLVMRustResult::Failure;
+      }
+      MOrErr->MemberName = sys::path::filename(MOrErr->MemberName);
+      Members.push_back(std::move(*MOrErr));
+    } else {
+      Expected<NewArchiveMember> MOrErr =
+          NewArchiveMember::getOldMember(Member->Child, true);
+      if (!MOrErr) {
+        LLVMRustSetLastError(toString(MOrErr.takeError()).c_str());
+        return LLVMRustResult::Failure;
+      }
+      Members.push_back(std::move(*MOrErr));
+    }
+  }
+
+  auto Result = writeArchive(Dst, Members, WriteSymbtab, Kind, true, false);
+  if (!Result)
+    return LLVMRustResult::Success;
+  LLVMRustSetLastError(toString(std::move(Result)).c_str());
+
+  return LLVMRustResult::Failure;
+}
diff --git a/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
new file mode 100644
index 00000000000..2b1143a4ecf
--- /dev/null
+++ b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
@@ -0,0 +1,70 @@
+#include "LLVMWrapper.h"
+#include "llvm/ProfileData/Coverage/CoverageMapping.h"
+#include "llvm/ProfileData/Coverage/CoverageMappingWriter.h"
+#include "llvm/ProfileData/InstrProf.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/Support/LEB128.h"
+
+#include <iostream>
+
+using namespace llvm;
+
+extern "C" void LLVMRustCoverageWriteFilenamesSectionToBuffer(
+    const char* const Filenames[],
+    size_t FilenamesLen,
+    RustStringRef BufferOut) {
+  // LLVM 11's CoverageFilenamesSectionWriter uses its new `Version4` format,
+  // so we're manually writing the `Version3` format ourselves.
+  RawRustStringOstream OS(BufferOut);
+  encodeULEB128(FilenamesLen, OS);
+  for (size_t i = 0; i < FilenamesLen; i++) {
+    StringRef Filename(Filenames[i]);
+    encodeULEB128(Filename.size(), OS);
+    OS << Filename;
+  }
+}
+
+extern "C" void LLVMRustCoverageWriteMappingToBuffer(
+    const unsigned *VirtualFileMappingIDs,
+    unsigned NumVirtualFileMappingIDs,
+    const coverage::CounterExpression *Expressions,
+    unsigned NumExpressions,
+    coverage::CounterMappingRegion *MappingRegions,
+    unsigned NumMappingRegions,
+    RustStringRef BufferOut) {
+  auto CoverageMappingWriter = coverage::CoverageMappingWriter(
+      makeArrayRef(VirtualFileMappingIDs, NumVirtualFileMappingIDs),
+      makeArrayRef(Expressions, NumExpressions),
+      makeMutableArrayRef(MappingRegions, NumMappingRegions));
+  RawRustStringOstream OS(BufferOut);
+  CoverageMappingWriter.write(OS);
+}
+
+extern "C" LLVMValueRef LLVMRustCoverageCreatePGOFuncNameVar(LLVMValueRef F, const char *FuncName) {
+  StringRef FuncNameRef(FuncName);
+  return wrap(createPGOFuncNameVar(*cast<Function>(unwrap(F)), FuncNameRef));
+}
+
+extern "C" uint64_t LLVMRustCoverageComputeHash(const char *Name) {
+  StringRef NameRef(Name);
+  return IndexedInstrProf::ComputeHash(NameRef);
+}
+
+extern "C" void LLVMRustCoverageWriteSectionNameToString(LLVMModuleRef M,
+                                                         RustStringRef Str) {
+  Triple TargetTriple(unwrap(M)->getTargetTriple());
+  auto name = getInstrProfSectionName(IPSK_covmap,
+                                      TargetTriple.getObjectFormat());
+  RawRustStringOstream OS(Str);
+  OS << name;
+}
+
+extern "C" void LLVMRustCoverageWriteMappingVarNameToString(RustStringRef Str) {
+  auto name = getCoverageMappingVarName();
+  RawRustStringOstream OS(Str);
+  OS << name;
+}
+
+extern "C" uint32_t LLVMRustCoverageMappingVersion() {
+  return coverage::CovMapVersion::Version3;
+}
diff --git a/compiler/rustc_llvm/llvm-wrapper/LLVMWrapper.h b/compiler/rustc_llvm/llvm-wrapper/LLVMWrapper.h
new file mode 100644
index 00000000000..57b8664d3b6
--- /dev/null
+++ b/compiler/rustc_llvm/llvm-wrapper/LLVMWrapper.h
@@ -0,0 +1,115 @@
+#include "llvm-c/BitReader.h"
+#include "llvm-c/Core.h"
+#include "llvm-c/Object.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Analysis/Lint.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InlineAsm.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/DynamicLibrary.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/Memory.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/Instrumentation.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Vectorize.h"
+
+#define LLVM_VERSION_GE(major, minor)                                          \
+  (LLVM_VERSION_MAJOR > (major) ||                                             \
+   LLVM_VERSION_MAJOR == (major) && LLVM_VERSION_MINOR >= (minor))
+
+#define LLVM_VERSION_EQ(major, minor)                                          \
+  (LLVM_VERSION_MAJOR == (major) && LLVM_VERSION_MINOR == (minor))
+
+#define LLVM_VERSION_LE(major, minor)                                          \
+  (LLVM_VERSION_MAJOR < (major) ||                                             \
+   LLVM_VERSION_MAJOR == (major) && LLVM_VERSION_MINOR <= (minor))
+
+#define LLVM_VERSION_LT(major, minor) (!LLVM_VERSION_GE((major), (minor)))
+
+#include "llvm/IR/LegacyPassManager.h"
+
+#include "llvm/Bitcode/BitcodeReader.h"
+#include "llvm/Bitcode/BitcodeWriter.h"
+
+#include "llvm/IR/DIBuilder.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/IRPrintingPasses.h"
+#include "llvm/Linker/Linker.h"
+
+extern "C" void LLVMRustSetLastError(const char *);
+
+enum class LLVMRustResult { Success, Failure };
+
+enum LLVMRustAttribute {
+  AlwaysInline = 0,
+  ByVal = 1,
+  Cold = 2,
+  InlineHint = 3,
+  MinSize = 4,
+  Naked = 5,
+  NoAlias = 6,
+  NoCapture = 7,
+  NoInline = 8,
+  NonNull = 9,
+  NoRedZone = 10,
+  NoReturn = 11,
+  NoUnwind = 12,
+  OptimizeForSize = 13,
+  ReadOnly = 14,
+  SExt = 15,
+  StructRet = 16,
+  UWTable = 17,
+  ZExt = 18,
+  InReg = 19,
+  SanitizeThread = 20,
+  SanitizeAddress = 21,
+  SanitizeMemory = 22,
+  NonLazyBind = 23,
+  OptimizeNone = 24,
+  ReturnsTwice = 25,
+  ReadNone = 26,
+  InaccessibleMemOnly = 27,
+};
+
+typedef struct OpaqueRustString *RustStringRef;
+typedef struct LLVMOpaqueTwine *LLVMTwineRef;
+typedef struct LLVMOpaqueSMDiagnostic *LLVMSMDiagnosticRef;
+
+extern "C" void LLVMRustStringWriteImpl(RustStringRef Str, const char *Ptr,
+                                        size_t Size);
+
+class RawRustStringOstream : public llvm::raw_ostream {
+  RustStringRef Str;
+  uint64_t Pos;
+
+  void write_impl(const char *Ptr, size_t Size) override {
+    LLVMRustStringWriteImpl(Str, Ptr, Size);
+    Pos += Size;
+  }
+
+  uint64_t current_pos() const override { return Pos; }
+
+public:
+  explicit RawRustStringOstream(RustStringRef Str) : Str(Str), Pos(0) {}
+
+  ~RawRustStringOstream() {
+    // LLVM requires this.
+    flush();
+  }
+};
diff --git a/compiler/rustc_llvm/llvm-wrapper/Linker.cpp b/compiler/rustc_llvm/llvm-wrapper/Linker.cpp
new file mode 100644
index 00000000000..8766e96f086
--- /dev/null
+++ b/compiler/rustc_llvm/llvm-wrapper/Linker.cpp
@@ -0,0 +1,48 @@
+#include "llvm/Linker/Linker.h"
+
+#include "LLVMWrapper.h"
+
+using namespace llvm;
+
+struct RustLinker {
+  Linker L;
+  LLVMContext &Ctx;
+
+  RustLinker(Module &M) :
+    L(M),
+    Ctx(M.getContext())
+  {}
+};
+
+extern "C" RustLinker*
+LLVMRustLinkerNew(LLVMModuleRef DstRef) {
+  Module *Dst = unwrap(DstRef);
+
+  return new RustLinker(*Dst);
+}
+
+extern "C" void
+LLVMRustLinkerFree(RustLinker *L) {
+  delete L;
+}
+
+extern "C" bool
+LLVMRustLinkerAdd(RustLinker *L, char *BC, size_t Len) {
+  std::unique_ptr<MemoryBuffer> Buf =
+      MemoryBuffer::getMemBufferCopy(StringRef(BC, Len));
+
+  Expected<std::unique_ptr<Module>> SrcOrError =
+      llvm::getLazyBitcodeModule(Buf->getMemBufferRef(), L->Ctx);
+  if (!SrcOrError) {
+    LLVMRustSetLastError(toString(SrcOrError.takeError()).c_str());
+    return false;
+  }
+
+  auto Src = std::move(*SrcOrError);
+
+  if (L->L.linkInModule(std::move(Src))) {
+    LLVMRustSetLastError("");
+    return false;
+  }
+  return true;
+}
diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
new file mode 100644
index 00000000000..7b1c3f9ba2c
--- /dev/null
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -0,0 +1,1655 @@
+#include <stdio.h>
+
+#include <vector>
+#include <set>
+
+#include "LLVMWrapper.h"
+
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/IR/AutoUpgrade.h"
+#include "llvm/IR/AssemblyAnnotationWriter.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Object/IRObjectFile.h"
+#include "llvm/Passes/PassBuilder.h"
+#if LLVM_VERSION_GE(9, 0)
+#include "llvm/Passes/StandardInstrumentations.h"
+#endif
+#include "llvm/Support/CBindingWrapping.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Transforms/IPO/PassManagerBuilder.h"
+#include "llvm/Transforms/IPO/AlwaysInliner.h"
+#include "llvm/Transforms/IPO/FunctionImport.h"
+#include "llvm/Transforms/Utils/FunctionImportUtils.h"
+#include "llvm/LTO/LTO.h"
+#include "llvm-c/Transforms/PassManagerBuilder.h"
+
+#include "llvm/Transforms/Instrumentation.h"
+#if LLVM_VERSION_GE(9, 0)
+#include "llvm/Transforms/Instrumentation/AddressSanitizer.h"
+#include "llvm/Support/TimeProfiler.h"
+#endif
+#include "llvm/Transforms/Instrumentation/ThreadSanitizer.h"
+#include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
+#if LLVM_VERSION_GE(9, 0)
+#include "llvm/Transforms/Utils/CanonicalizeAliases.h"
+#endif
+#include "llvm/Transforms/Utils/NameAnonGlobals.h"
+
+using namespace llvm;
+
+typedef struct LLVMOpaquePass *LLVMPassRef;
+typedef struct LLVMOpaqueTargetMachine *LLVMTargetMachineRef;
+
+DEFINE_STDCXX_CONVERSION_FUNCTIONS(Pass, LLVMPassRef)
+DEFINE_STDCXX_CONVERSION_FUNCTIONS(TargetMachine, LLVMTargetMachineRef)
+#if LLVM_VERSION_LT(11, 0)
+DEFINE_STDCXX_CONVERSION_FUNCTIONS(PassManagerBuilder,
+                                   LLVMPassManagerBuilderRef)
+#endif
+
+extern "C" void LLVMInitializePasses() {
+  PassRegistry &Registry = *PassRegistry::getPassRegistry();
+  initializeCore(Registry);
+  initializeCodeGen(Registry);
+  initializeScalarOpts(Registry);
+  initializeVectorization(Registry);
+  initializeIPO(Registry);
+  initializeAnalysis(Registry);
+  initializeTransformUtils(Registry);
+  initializeInstCombine(Registry);
+  initializeInstrumentation(Registry);
+  initializeTarget(Registry);
+}
+
+extern "C" void LLVMTimeTraceProfilerInitialize() {
+#if LLVM_VERSION_GE(10, 0)
+  timeTraceProfilerInitialize(
+      /* TimeTraceGranularity */ 0,
+      /* ProcName */ "rustc");
+#elif LLVM_VERSION_GE(9, 0)
+  timeTraceProfilerInitialize();
+#endif
+}
+
+extern "C" void LLVMTimeTraceProfilerFinish(const char* FileName) {
+#if LLVM_VERSION_GE(9, 0)
+  StringRef FN(FileName);
+  std::error_code EC;
+  raw_fd_ostream OS(FN, EC, sys::fs::CD_CreateAlways);
+
+  timeTraceProfilerWrite(OS);
+  timeTraceProfilerCleanup();
+#endif
+}
+
+enum class LLVMRustPassKind {
+  Other,
+  Function,
+  Module,
+};
+
+static LLVMRustPassKind toRust(PassKind Kind) {
+  switch (Kind) {
+  case PT_Function:
+    return LLVMRustPassKind::Function;
+  case PT_Module:
+    return LLVMRustPassKind::Module;
+  default:
+    return LLVMRustPassKind::Other;
+  }
+}
+
+extern "C" LLVMPassRef LLVMRustFindAndCreatePass(const char *PassName) {
+  StringRef SR(PassName);
+  PassRegistry *PR = PassRegistry::getPassRegistry();
+
+  const PassInfo *PI = PR->getPassInfo(SR);
+  if (PI) {
+    return wrap(PI->createPass());
+  }
+  return nullptr;
+}
+
+extern "C" LLVMPassRef LLVMRustCreateAddressSanitizerFunctionPass(bool Recover) {
+  const bool CompileKernel = false;
+  const bool UseAfterScope = true;
+
+  return wrap(createAddressSanitizerFunctionPass(CompileKernel, Recover, UseAfterScope));
+}
+
+extern "C" LLVMPassRef LLVMRustCreateModuleAddressSanitizerPass(bool Recover) {
+  const bool CompileKernel = false;
+
+#if LLVM_VERSION_GE(9, 0)
+  return wrap(createModuleAddressSanitizerLegacyPassPass(CompileKernel, Recover));
+#else
+  return wrap(createAddressSanitizerModulePass(CompileKernel, Recover));
+#endif
+}
+
+extern "C" LLVMPassRef LLVMRustCreateMemorySanitizerPass(int TrackOrigins, bool Recover) {
+#if LLVM_VERSION_GE(9, 0)
+  const bool CompileKernel = false;
+
+  return wrap(createMemorySanitizerLegacyPassPass(
+      MemorySanitizerOptions{TrackOrigins, Recover, CompileKernel}));
+#else
+  return wrap(createMemorySanitizerLegacyPassPass(TrackOrigins, Recover));
+#endif
+}
+
+extern "C" LLVMPassRef LLVMRustCreateThreadSanitizerPass() {
+  return wrap(createThreadSanitizerLegacyPassPass());
+}
+
+extern "C" LLVMRustPassKind LLVMRustPassKind(LLVMPassRef RustPass) {
+  assert(RustPass);
+  Pass *Pass = unwrap(RustPass);
+  return toRust(Pass->getPassKind());
+}
+
+extern "C" void LLVMRustAddPass(LLVMPassManagerRef PMR, LLVMPassRef RustPass) {
+  assert(RustPass);
+  Pass *Pass = unwrap(RustPass);
+  PassManagerBase *PMB = unwrap(PMR);
+  PMB->add(Pass);
+}
+
+extern "C"
+void LLVMRustPassManagerBuilderPopulateThinLTOPassManager(
+  LLVMPassManagerBuilderRef PMBR,
+  LLVMPassManagerRef PMR
+) {
+  unwrap(PMBR)->populateThinLTOPassManager(*unwrap(PMR));
+}
+
+extern "C"
+void LLVMRustAddLastExtensionPasses(
+    LLVMPassManagerBuilderRef PMBR, LLVMPassRef *Passes, size_t NumPasses) {
+  auto AddExtensionPasses = [Passes, NumPasses](
+      const PassManagerBuilder &Builder, PassManagerBase &PM) {
+    for (size_t I = 0; I < NumPasses; I++) {
+      PM.add(unwrap(Passes[I]));
+    }
+  };
+  // Add the passes to both of the pre-finalization extension points,
+  // so they are run for optimized and non-optimized builds.
+  unwrap(PMBR)->addExtension(PassManagerBuilder::EP_OptimizerLast,
+                             AddExtensionPasses);
+  unwrap(PMBR)->addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
+                             AddExtensionPasses);
+}
+
+#ifdef LLVM_COMPONENT_X86
+#define SUBTARGET_X86 SUBTARGET(X86)
+#else
+#define SUBTARGET_X86
+#endif
+
+#ifdef LLVM_COMPONENT_ARM
+#define SUBTARGET_ARM SUBTARGET(ARM)
+#else
+#define SUBTARGET_ARM
+#endif
+
+#ifdef LLVM_COMPONENT_AARCH64
+#define SUBTARGET_AARCH64 SUBTARGET(AArch64)
+#else
+#define SUBTARGET_AARCH64
+#endif
+
+#ifdef LLVM_COMPONENT_AVR
+#define SUBTARGET_AVR SUBTARGET(AVR)
+#else
+#define SUBTARGET_AVR
+#endif
+
+#ifdef LLVM_COMPONENT_MIPS
+#define SUBTARGET_MIPS SUBTARGET(Mips)
+#else
+#define SUBTARGET_MIPS
+#endif
+
+#ifdef LLVM_COMPONENT_POWERPC
+#define SUBTARGET_PPC SUBTARGET(PPC)
+#else
+#define SUBTARGET_PPC
+#endif
+
+#ifdef LLVM_COMPONENT_SYSTEMZ
+#define SUBTARGET_SYSTEMZ SUBTARGET(SystemZ)
+#else
+#define SUBTARGET_SYSTEMZ
+#endif
+
+#ifdef LLVM_COMPONENT_MSP430
+#define SUBTARGET_MSP430 SUBTARGET(MSP430)
+#else
+#define SUBTARGET_MSP430
+#endif
+
+#ifdef LLVM_COMPONENT_RISCV
+#define SUBTARGET_RISCV SUBTARGET(RISCV)
+#else
+#define SUBTARGET_RISCV
+#endif
+
+#ifdef LLVM_COMPONENT_SPARC
+#define SUBTARGET_SPARC SUBTARGET(Sparc)
+#else
+#define SUBTARGET_SPARC
+#endif
+
+#ifdef LLVM_COMPONENT_HEXAGON
+#define SUBTARGET_HEXAGON SUBTARGET(Hexagon)
+#else
+#define SUBTARGET_HEXAGON
+#endif
+
+#define GEN_SUBTARGETS                                                         \
+  SUBTARGET_X86                                                                \
+  SUBTARGET_ARM                                                                \
+  SUBTARGET_AARCH64                                                            \
+  SUBTARGET_AVR                                                                \
+  SUBTARGET_MIPS                                                               \
+  SUBTARGET_PPC                                                                \
+  SUBTARGET_SYSTEMZ                                                            \
+  SUBTARGET_MSP430                                                             \
+  SUBTARGET_SPARC                                                              \
+  SUBTARGET_HEXAGON                                                            \
+  SUBTARGET_RISCV                                                              \
+
+#define SUBTARGET(x)                                                           \
+  namespace llvm {                                                             \
+  extern const SubtargetFeatureKV x##FeatureKV[];                              \
+  extern const SubtargetFeatureKV x##SubTypeKV[];                              \
+  }
+
+GEN_SUBTARGETS
+#undef SUBTARGET
+
+extern "C" bool LLVMRustHasFeature(LLVMTargetMachineRef TM,
+                                   const char *Feature) {
+  TargetMachine *Target = unwrap(TM);
+  const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo();
+  return MCInfo->checkFeatures(std::string("+") + Feature);
+}
+
+enum class LLVMRustCodeModel {
+  Tiny,
+  Small,
+  Kernel,
+  Medium,
+  Large,
+  None,
+};
+
+static Optional<CodeModel::Model> fromRust(LLVMRustCodeModel Model) {
+  switch (Model) {
+  case LLVMRustCodeModel::Tiny:
+    return CodeModel::Tiny;
+  case LLVMRustCodeModel::Small:
+    return CodeModel::Small;
+  case LLVMRustCodeModel::Kernel:
+    return CodeModel::Kernel;
+  case LLVMRustCodeModel::Medium:
+    return CodeModel::Medium;
+  case LLVMRustCodeModel::Large:
+    return CodeModel::Large;
+  case LLVMRustCodeModel::None:
+    return None;
+  default:
+    report_fatal_error("Bad CodeModel.");
+  }
+}
+
+enum class LLVMRustCodeGenOptLevel {
+  None,
+  Less,
+  Default,
+  Aggressive,
+};
+
+static CodeGenOpt::Level fromRust(LLVMRustCodeGenOptLevel Level) {
+  switch (Level) {
+  case LLVMRustCodeGenOptLevel::None:
+    return CodeGenOpt::None;
+  case LLVMRustCodeGenOptLevel::Less:
+    return CodeGenOpt::Less;
+  case LLVMRustCodeGenOptLevel::Default:
+    return CodeGenOpt::Default;
+  case LLVMRustCodeGenOptLevel::Aggressive:
+    return CodeGenOpt::Aggressive;
+  default:
+    report_fatal_error("Bad CodeGenOptLevel.");
+  }
+}
+
+enum class LLVMRustPassBuilderOptLevel {
+  O0,
+  O1,
+  O2,
+  O3,
+  Os,
+  Oz,
+};
+
+static PassBuilder::OptimizationLevel fromRust(LLVMRustPassBuilderOptLevel Level) {
+  switch (Level) {
+  case LLVMRustPassBuilderOptLevel::O0:
+    return PassBuilder::OptimizationLevel::O0;
+  case LLVMRustPassBuilderOptLevel::O1:
+    return PassBuilder::OptimizationLevel::O1;
+  case LLVMRustPassBuilderOptLevel::O2:
+    return PassBuilder::OptimizationLevel::O2;
+  case LLVMRustPassBuilderOptLevel::O3:
+    return PassBuilder::OptimizationLevel::O3;
+  case LLVMRustPassBuilderOptLevel::Os:
+    return PassBuilder::OptimizationLevel::Os;
+  case LLVMRustPassBuilderOptLevel::Oz:
+    return PassBuilder::OptimizationLevel::Oz;
+  default:
+    report_fatal_error("Bad PassBuilderOptLevel.");
+  }
+}
+
+enum class LLVMRustRelocModel {
+  Static,
+  PIC,
+  DynamicNoPic,
+  ROPI,
+  RWPI,
+  ROPIRWPI,
+};
+
+static Reloc::Model fromRust(LLVMRustRelocModel RustReloc) {
+  switch (RustReloc) {
+  case LLVMRustRelocModel::Static:
+    return Reloc::Static;
+  case LLVMRustRelocModel::PIC:
+    return Reloc::PIC_;
+  case LLVMRustRelocModel::DynamicNoPic:
+    return Reloc::DynamicNoPIC;
+  case LLVMRustRelocModel::ROPI:
+    return Reloc::ROPI;
+  case LLVMRustRelocModel::RWPI:
+    return Reloc::RWPI;
+  case LLVMRustRelocModel::ROPIRWPI:
+    return Reloc::ROPI_RWPI;
+  }
+  report_fatal_error("Bad RelocModel.");
+}
+
+#ifdef LLVM_RUSTLLVM
+/// getLongestEntryLength - Return the length of the longest entry in the table.
+template<typename KV>
+static size_t getLongestEntryLength(ArrayRef<KV> Table) {
+  size_t MaxLen = 0;
+  for (auto &I : Table)
+    MaxLen = std::max(MaxLen, std::strlen(I.Key));
+  return MaxLen;
+}
+
+extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef TM) {
+  const TargetMachine *Target = unwrap(TM);
+  const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo();
+  const Triple::ArchType HostArch = Triple(sys::getProcessTriple()).getArch();
+  const Triple::ArchType TargetArch = Target->getTargetTriple().getArch();
+  const ArrayRef<SubtargetSubTypeKV> CPUTable = MCInfo->getCPUTable();
+  unsigned MaxCPULen = getLongestEntryLength(CPUTable);
+
+  printf("Available CPUs for this target:\n");
+  if (HostArch == TargetArch) {
+    const StringRef HostCPU = sys::getHostCPUName();
+    printf("    %-*s - Select the CPU of the current host (currently %.*s).\n",
+      MaxCPULen, "native", (int)HostCPU.size(), HostCPU.data());
+  }
+  for (auto &CPU : CPUTable)
+    printf("    %-*s\n", MaxCPULen, CPU.Key);
+  printf("\n");
+}
+
+extern "C" void LLVMRustPrintTargetFeatures(LLVMTargetMachineRef TM) {
+  const TargetMachine *Target = unwrap(TM);
+  const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo();
+  const ArrayRef<SubtargetFeatureKV> FeatTable = MCInfo->getFeatureTable();
+  unsigned MaxFeatLen = getLongestEntryLength(FeatTable);
+
+  printf("Available features for this target:\n");
+  for (auto &Feature : FeatTable)
+    printf("    %-*s - %s.\n", MaxFeatLen, Feature.Key, Feature.Desc);
+  printf("\nRust-specific features:\n");
+  printf("    %-*s - %s.\n",
+    MaxFeatLen,
+    "crt-static",
+    "Enables libraries with C Run-time Libraries(CRT) to be statically linked"
+  );
+  printf("\n");
+
+  printf("Use +feature to enable a feature, or -feature to disable it.\n"
+         "For example, rustc -C -target-cpu=mycpu -C "
+         "target-feature=+feature1,-feature2\n\n");
+}
+
+#else
+
+extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef) {
+  printf("Target CPU help is not supported by this LLVM version.\n\n");
+}
+
+extern "C" void LLVMRustPrintTargetFeatures(LLVMTargetMachineRef) {
+  printf("Target features help is not supported by this LLVM version.\n\n");
+}
+#endif
+
+extern "C" const char* LLVMRustGetHostCPUName(size_t *len) {
+  StringRef Name = sys::getHostCPUName();
+  *len = Name.size();
+  return Name.data();
+}
+
+extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
+    const char *TripleStr, const char *CPU, const char *Feature,
+    const char *ABIStr, LLVMRustCodeModel RustCM, LLVMRustRelocModel RustReloc,
+    LLVMRustCodeGenOptLevel RustOptLevel, bool UseSoftFloat,
+    bool FunctionSections,
+    bool DataSections,
+    bool TrapUnreachable,
+    bool Singlethread,
+    bool AsmComments,
+    bool EmitStackSizeSection,
+    bool RelaxELFRelocations,
+    bool UseInitArray) {
+
+  auto OptLevel = fromRust(RustOptLevel);
+  auto RM = fromRust(RustReloc);
+  auto CM = fromRust(RustCM);
+
+  std::string Error;
+  Triple Trip(Triple::normalize(TripleStr));
+  const llvm::Target *TheTarget =
+      TargetRegistry::lookupTarget(Trip.getTriple(), Error);
+  if (TheTarget == nullptr) {
+    LLVMRustSetLastError(Error.c_str());
+    return nullptr;
+  }
+
+  TargetOptions Options;
+
+  Options.FloatABIType = FloatABI::Default;
+  if (UseSoftFloat) {
+    Options.FloatABIType = FloatABI::Soft;
+  }
+  Options.DataSections = DataSections;
+  Options.FunctionSections = FunctionSections;
+  Options.MCOptions.AsmVerbose = AsmComments;
+  Options.MCOptions.PreserveAsmComments = AsmComments;
+  Options.MCOptions.ABIName = ABIStr;
+  Options.RelaxELFRelocations = RelaxELFRelocations;
+  Options.UseInitArray = UseInitArray;
+
+  if (TrapUnreachable) {
+    // Tell LLVM to codegen `unreachable` into an explicit trap instruction.
+    // This limits the extent of possible undefined behavior in some cases, as
+    // it prevents control flow from "falling through" into whatever code
+    // happens to be laid out next in memory.
+    Options.TrapUnreachable = true;
+  }
+
+  if (Singlethread) {
+    Options.ThreadModel = ThreadModel::Single;
+  }
+
+  Options.EmitStackSizeSection = EmitStackSizeSection;
+
+  TargetMachine *TM = TheTarget->createTargetMachine(
+      Trip.getTriple(), CPU, Feature, Options, RM, CM, OptLevel);
+  return wrap(TM);
+}
+
+extern "C" void LLVMRustDisposeTargetMachine(LLVMTargetMachineRef TM) {
+  delete unwrap(TM);
+}
+
+extern "C" void LLVMRustConfigurePassManagerBuilder(
+    LLVMPassManagerBuilderRef PMBR, LLVMRustCodeGenOptLevel OptLevel,
+    bool MergeFunctions, bool SLPVectorize, bool LoopVectorize, bool PrepareForThinLTO,
+    const char* PGOGenPath, const char* PGOUsePath) {
+  unwrap(PMBR)->MergeFunctions = MergeFunctions;
+  unwrap(PMBR)->SLPVectorize = SLPVectorize;
+  unwrap(PMBR)->OptLevel = fromRust(OptLevel);
+  unwrap(PMBR)->LoopVectorize = LoopVectorize;
+  unwrap(PMBR)->PrepareForThinLTO = PrepareForThinLTO;
+
+  if (PGOGenPath) {
+    assert(!PGOUsePath);
+    unwrap(PMBR)->EnablePGOInstrGen = true;
+    unwrap(PMBR)->PGOInstrGen = PGOGenPath;
+  }
+  if (PGOUsePath) {
+    assert(!PGOGenPath);
+    unwrap(PMBR)->PGOInstrUse = PGOUsePath;
+  }
+}
+
+// Unfortunately, the LLVM C API doesn't provide a way to set the `LibraryInfo`
+// field of a PassManagerBuilder, we expose our own method of doing so.
+extern "C" void LLVMRustAddBuilderLibraryInfo(LLVMPassManagerBuilderRef PMBR,
+                                              LLVMModuleRef M,
+                                              bool DisableSimplifyLibCalls) {
+  Triple TargetTriple(unwrap(M)->getTargetTriple());
+  TargetLibraryInfoImpl *TLI = new TargetLibraryInfoImpl(TargetTriple);
+  if (DisableSimplifyLibCalls)
+    TLI->disableAllFunctions();
+  unwrap(PMBR)->LibraryInfo = TLI;
+}
+
+// Unfortunately, the LLVM C API doesn't provide a way to create the
+// TargetLibraryInfo pass, so we use this method to do so.
+extern "C" void LLVMRustAddLibraryInfo(LLVMPassManagerRef PMR, LLVMModuleRef M,
+                                       bool DisableSimplifyLibCalls) {
+  Triple TargetTriple(unwrap(M)->getTargetTriple());
+  TargetLibraryInfoImpl TLII(TargetTriple);
+  if (DisableSimplifyLibCalls)
+    TLII.disableAllFunctions();
+  unwrap(PMR)->add(new TargetLibraryInfoWrapperPass(TLII));
+}
+
+// Unfortunately, the LLVM C API doesn't provide an easy way of iterating over
+// all the functions in a module, so we do that manually here. You'll find
+// similar code in clang's BackendUtil.cpp file.
+extern "C" void LLVMRustRunFunctionPassManager(LLVMPassManagerRef PMR,
+                                               LLVMModuleRef M) {
+  llvm::legacy::FunctionPassManager *P =
+      unwrap<llvm::legacy::FunctionPassManager>(PMR);
+  P->doInitialization();
+
+  // Upgrade all calls to old intrinsics first.
+  for (Module::iterator I = unwrap(M)->begin(), E = unwrap(M)->end(); I != E;)
+    UpgradeCallsToIntrinsic(&*I++); // must be post-increment, as we remove
+
+  for (Module::iterator I = unwrap(M)->begin(), E = unwrap(M)->end(); I != E;
+       ++I)
+    if (!I->isDeclaration())
+      P->run(*I);
+
+  P->doFinalization();
+}
+
+extern "C" void LLVMRustSetLLVMOptions(int Argc, char **Argv) {
+  // Initializing the command-line options more than once is not allowed. So,
+  // check if they've already been initialized.  (This could happen if we're
+  // being called from rustpkg, for example). If the arguments change, then
+  // that's just kinda unfortunate.
+  static bool Initialized = false;
+  if (Initialized)
+    return;
+  Initialized = true;
+  cl::ParseCommandLineOptions(Argc, Argv);
+}
+
+enum class LLVMRustFileType {
+  AssemblyFile,
+  ObjectFile,
+};
+
+#if LLVM_VERSION_GE(10, 0)
+static CodeGenFileType fromRust(LLVMRustFileType Type) {
+  switch (Type) {
+  case LLVMRustFileType::AssemblyFile:
+    return CGFT_AssemblyFile;
+  case LLVMRustFileType::ObjectFile:
+    return CGFT_ObjectFile;
+  default:
+    report_fatal_error("Bad FileType.");
+  }
+}
+#else
+static TargetMachine::CodeGenFileType fromRust(LLVMRustFileType Type) {
+  switch (Type) {
+  case LLVMRustFileType::AssemblyFile:
+    return TargetMachine::CGFT_AssemblyFile;
+  case LLVMRustFileType::ObjectFile:
+    return TargetMachine::CGFT_ObjectFile;
+  default:
+    report_fatal_error("Bad FileType.");
+  }
+}
+#endif
+
+extern "C" LLVMRustResult
+LLVMRustWriteOutputFile(LLVMTargetMachineRef Target, LLVMPassManagerRef PMR,
+                        LLVMModuleRef M, const char *Path,
+                        LLVMRustFileType RustFileType) {
+  llvm::legacy::PassManager *PM = unwrap<llvm::legacy::PassManager>(PMR);
+  auto FileType = fromRust(RustFileType);
+
+  std::string ErrorInfo;
+  std::error_code EC;
+  raw_fd_ostream OS(Path, EC, sys::fs::F_None);
+  if (EC)
+    ErrorInfo = EC.message();
+  if (ErrorInfo != "") {
+    LLVMRustSetLastError(ErrorInfo.c_str());
+    return LLVMRustResult::Failure;
+  }
+
+  buffer_ostream BOS(OS);
+  unwrap(Target)->addPassesToEmitFile(*PM, BOS, nullptr, FileType, false);
+  PM->run(*unwrap(M));
+
+  // Apparently `addPassesToEmitFile` adds a pointer to our on-the-stack output
+  // stream (OS), so the only real safe place to delete this is here? Don't we
+  // wish this was written in Rust?
+  LLVMDisposePassManager(PMR);
+  return LLVMRustResult::Success;
+}
+
+extern "C" typedef void (*LLVMRustSelfProfileBeforePassCallback)(void*, // LlvmSelfProfiler
+                                                      const char*,      // pass name
+                                                      const char*);     // IR name
+extern "C" typedef void (*LLVMRustSelfProfileAfterPassCallback)(void*); // LlvmSelfProfiler
+
+#if LLVM_VERSION_GE(9, 0)
+
+std::string LLVMRustwrappedIrGetName(const llvm::Any &WrappedIr) {
+  if (any_isa<const Module *>(WrappedIr))
+    return any_cast<const Module *>(WrappedIr)->getName().str();
+  if (any_isa<const Function *>(WrappedIr))
+    return any_cast<const Function *>(WrappedIr)->getName().str();
+  if (any_isa<const Loop *>(WrappedIr))
+    return any_cast<const Loop *>(WrappedIr)->getName().str();
+  if (any_isa<const LazyCallGraph::SCC *>(WrappedIr))
+    return any_cast<const LazyCallGraph::SCC *>(WrappedIr)->getName();
+  return "<UNKNOWN>";
+}
+
+
+void LLVMSelfProfileInitializeCallbacks(
+    PassInstrumentationCallbacks& PIC, void* LlvmSelfProfiler,
+    LLVMRustSelfProfileBeforePassCallback BeforePassCallback,
+    LLVMRustSelfProfileAfterPassCallback AfterPassCallback) {
+  PIC.registerBeforePassCallback([LlvmSelfProfiler, BeforePassCallback](
+                                     StringRef Pass, llvm::Any Ir) {
+    std::string PassName = Pass.str();
+    std::string IrName = LLVMRustwrappedIrGetName(Ir);
+    BeforePassCallback(LlvmSelfProfiler, PassName.c_str(), IrName.c_str());
+    return true;
+  });
+
+  PIC.registerAfterPassCallback(
+      [LlvmSelfProfiler, AfterPassCallback](StringRef Pass, llvm::Any Ir) {
+        AfterPassCallback(LlvmSelfProfiler);
+      });
+
+  PIC.registerAfterPassInvalidatedCallback(
+      [LlvmSelfProfiler, AfterPassCallback](StringRef Pass) {
+        AfterPassCallback(LlvmSelfProfiler);
+      });
+
+  PIC.registerBeforeAnalysisCallback([LlvmSelfProfiler, BeforePassCallback](
+                                         StringRef Pass, llvm::Any Ir) {
+    std::string PassName = Pass.str();
+    std::string IrName = LLVMRustwrappedIrGetName(Ir);
+    BeforePassCallback(LlvmSelfProfiler, PassName.c_str(), IrName.c_str());
+  });
+
+  PIC.registerAfterAnalysisCallback(
+      [LlvmSelfProfiler, AfterPassCallback](StringRef Pass, llvm::Any Ir) {
+        AfterPassCallback(LlvmSelfProfiler);
+      });
+}
+#endif
+
+enum class LLVMRustOptStage {
+  PreLinkNoLTO,
+  PreLinkThinLTO,
+  PreLinkFatLTO,
+  ThinLTO,
+  FatLTO,
+};
+
+struct LLVMRustSanitizerOptions {
+  bool SanitizeAddress;
+  bool SanitizeAddressRecover;
+  bool SanitizeMemory;
+  bool SanitizeMemoryRecover;
+  int  SanitizeMemoryTrackOrigins;
+  bool SanitizeThread;
+};
+
+extern "C" void
+LLVMRustOptimizeWithNewPassManager(
+    LLVMModuleRef ModuleRef,
+    LLVMTargetMachineRef TMRef,
+    LLVMRustPassBuilderOptLevel OptLevelRust,
+    LLVMRustOptStage OptStage,
+    bool NoPrepopulatePasses, bool VerifyIR, bool UseThinLTOBuffers,
+    bool MergeFunctions, bool UnrollLoops, bool SLPVectorize, bool LoopVectorize,
+    bool DisableSimplifyLibCalls, bool EmitLifetimeMarkers,
+    LLVMRustSanitizerOptions *SanitizerOptions,
+    const char *PGOGenPath, const char *PGOUsePath,
+    void* LlvmSelfProfiler,
+    LLVMRustSelfProfileBeforePassCallback BeforePassCallback,
+    LLVMRustSelfProfileAfterPassCallback AfterPassCallback) {
+#if LLVM_VERSION_GE(9, 0)
+  Module *TheModule = unwrap(ModuleRef);
+  TargetMachine *TM = unwrap(TMRef);
+  PassBuilder::OptimizationLevel OptLevel = fromRust(OptLevelRust);
+
+  // FIXME: MergeFunctions is not supported by NewPM yet.
+  (void) MergeFunctions;
+
+  PipelineTuningOptions PTO;
+  PTO.LoopUnrolling = UnrollLoops;
+  PTO.LoopInterleaving = UnrollLoops;
+  PTO.LoopVectorization = LoopVectorize;
+  PTO.SLPVectorization = SLPVectorize;
+
+  PassInstrumentationCallbacks PIC;
+  StandardInstrumentations SI;
+  SI.registerCallbacks(PIC);
+
+  if (LlvmSelfProfiler){
+    LLVMSelfProfileInitializeCallbacks(PIC,LlvmSelfProfiler,BeforePassCallback,AfterPassCallback);
+  }
+
+  Optional<PGOOptions> PGOOpt;
+  if (PGOGenPath) {
+    assert(!PGOUsePath);
+    PGOOpt = PGOOptions(PGOGenPath, "", "", PGOOptions::IRInstr);
+  } else if (PGOUsePath) {
+    assert(!PGOGenPath);
+    PGOOpt = PGOOptions(PGOUsePath, "", "", PGOOptions::IRUse);
+  }
+
+  PassBuilder PB(TM, PTO, PGOOpt, &PIC);
+
+  // FIXME: We may want to expose this as an option.
+  bool DebugPassManager = false;
+  LoopAnalysisManager LAM(DebugPassManager);
+  FunctionAnalysisManager FAM(DebugPassManager);
+  CGSCCAnalysisManager CGAM(DebugPassManager);
+  ModuleAnalysisManager MAM(DebugPassManager);
+
+  FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
+
+  Triple TargetTriple(TheModule->getTargetTriple());
+  std::unique_ptr<TargetLibraryInfoImpl> TLII(new TargetLibraryInfoImpl(TargetTriple));
+  if (DisableSimplifyLibCalls)
+    TLII->disableAllFunctions();
+  FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
+
+  PB.registerModuleAnalyses(MAM);
+  PB.registerCGSCCAnalyses(CGAM);
+  PB.registerFunctionAnalyses(FAM);
+  PB.registerLoopAnalyses(LAM);
+  PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
+
+  // We manually collect pipeline callbacks so we can apply them at O0, where the
+  // PassBuilder does not create a pipeline.
+  std::vector<std::function<void(ModulePassManager &)>> PipelineStartEPCallbacks;
+#if LLVM_VERSION_GE(11, 0)
+  std::vector<std::function<void(ModulePassManager &, PassBuilder::OptimizationLevel)>>
+      OptimizerLastEPCallbacks;
+#else
+  std::vector<std::function<void(FunctionPassManager &, PassBuilder::OptimizationLevel)>>
+      OptimizerLastEPCallbacks;
+#endif
+
+  if (VerifyIR) {
+    PipelineStartEPCallbacks.push_back([VerifyIR](ModulePassManager &MPM) {
+        MPM.addPass(VerifierPass());
+    });
+  }
+
+  if (SanitizerOptions) {
+    if (SanitizerOptions->SanitizeMemory) {
+      MemorySanitizerOptions Options(
+          SanitizerOptions->SanitizeMemoryTrackOrigins,
+          SanitizerOptions->SanitizeMemoryRecover,
+          /*CompileKernel=*/false);
+#if LLVM_VERSION_GE(11, 0)
+      OptimizerLastEPCallbacks.push_back(
+        [Options](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
+          MPM.addPass(MemorySanitizerPass(Options));
+          MPM.addPass(createModuleToFunctionPassAdaptor(MemorySanitizerPass(Options)));
+        }
+      );
+#else
+#if LLVM_VERSION_GE(10, 0)
+      PipelineStartEPCallbacks.push_back([Options](ModulePassManager &MPM) {
+        MPM.addPass(MemorySanitizerPass(Options));
+      });
+#endif
+      OptimizerLastEPCallbacks.push_back(
+        [Options](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
+          FPM.addPass(MemorySanitizerPass(Options));
+        }
+      );
+#endif
+    }
+
+    if (SanitizerOptions->SanitizeThread) {
+#if LLVM_VERSION_GE(11, 0)
+      OptimizerLastEPCallbacks.push_back(
+        [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
+          MPM.addPass(ThreadSanitizerPass());
+          MPM.addPass(createModuleToFunctionPassAdaptor(ThreadSanitizerPass()));
+        }
+      );
+#else
+#if LLVM_VERSION_GE(10, 0)
+      PipelineStartEPCallbacks.push_back([](ModulePassManager &MPM) {
+        MPM.addPass(ThreadSanitizerPass());
+      });
+#endif
+      OptimizerLastEPCallbacks.push_back(
+        [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
+          FPM.addPass(ThreadSanitizerPass());
+        }
+      );
+#endif
+    }
+
+    if (SanitizerOptions->SanitizeAddress) {
+#if LLVM_VERSION_GE(11, 0)
+      OptimizerLastEPCallbacks.push_back(
+        [SanitizerOptions](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
+          MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
+          MPM.addPass(ModuleAddressSanitizerPass(
+              /*CompileKernel=*/false, SanitizerOptions->SanitizeAddressRecover));
+          MPM.addPass(createModuleToFunctionPassAdaptor(AddressSanitizerPass(
+              /*CompileKernel=*/false, SanitizerOptions->SanitizeAddressRecover,
+              /*UseAfterScope=*/true)));
+        }
+      );
+#else
+      PipelineStartEPCallbacks.push_back([&](ModulePassManager &MPM) {
+        MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
+      });
+      OptimizerLastEPCallbacks.push_back(
+        [SanitizerOptions](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
+          FPM.addPass(AddressSanitizerPass(
+              /*CompileKernel=*/false, SanitizerOptions->SanitizeAddressRecover,
+              /*UseAfterScope=*/true));
+        }
+      );
+      PipelineStartEPCallbacks.push_back(
+        [SanitizerOptions](ModulePassManager &MPM) {
+          MPM.addPass(ModuleAddressSanitizerPass(
+              /*CompileKernel=*/false, SanitizerOptions->SanitizeAddressRecover));
+        }
+      );
+#endif
+    }
+  }
+
+  ModulePassManager MPM(DebugPassManager);
+  if (!NoPrepopulatePasses) {
+    if (OptLevel == PassBuilder::OptimizationLevel::O0) {
+      for (const auto &C : PipelineStartEPCallbacks)
+        C(MPM);
+
+#if LLVM_VERSION_GE(11, 0)
+      for (const auto &C : OptimizerLastEPCallbacks)
+        C(MPM, OptLevel);
+#else
+      if (!OptimizerLastEPCallbacks.empty()) {
+        FunctionPassManager FPM(DebugPassManager);
+        for (const auto &C : OptimizerLastEPCallbacks)
+          C(FPM, OptLevel);
+        MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
+      }
+#endif
+
+      MPM.addPass(AlwaysInlinerPass(EmitLifetimeMarkers));
+
+#if LLVM_VERSION_GE(10, 0)
+      if (PGOOpt) {
+        PB.addPGOInstrPassesForO0(
+            MPM, DebugPassManager, PGOOpt->Action == PGOOptions::IRInstr,
+            /*IsCS=*/false, PGOOpt->ProfileFile, PGOOpt->ProfileRemappingFile);
+      }
+#endif
+    } else {
+      for (const auto &C : PipelineStartEPCallbacks)
+        PB.registerPipelineStartEPCallback(C);
+      if (OptStage != LLVMRustOptStage::PreLinkThinLTO) {
+        for (const auto &C : OptimizerLastEPCallbacks)
+          PB.registerOptimizerLastEPCallback(C);
+      }
+
+      switch (OptStage) {
+      case LLVMRustOptStage::PreLinkNoLTO:
+        MPM = PB.buildPerModuleDefaultPipeline(OptLevel, DebugPassManager);
+        break;
+      case LLVMRustOptStage::PreLinkThinLTO:
+        MPM = PB.buildThinLTOPreLinkDefaultPipeline(OptLevel, DebugPassManager);
+#if LLVM_VERSION_GE(11, 0)
+        for (const auto &C : OptimizerLastEPCallbacks)
+          C(MPM, OptLevel);
+#else
+        if (!OptimizerLastEPCallbacks.empty()) {
+          FunctionPassManager FPM(DebugPassManager);
+          for (const auto &C : OptimizerLastEPCallbacks)
+            C(FPM, OptLevel);
+          MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
+        }
+#endif
+        break;
+      case LLVMRustOptStage::PreLinkFatLTO:
+        MPM = PB.buildLTOPreLinkDefaultPipeline(OptLevel, DebugPassManager);
+        break;
+      case LLVMRustOptStage::ThinLTO:
+        // FIXME: Does it make sense to pass the ModuleSummaryIndex?
+        // It only seems to be needed for C++ specific optimizations.
+        MPM = PB.buildThinLTODefaultPipeline(OptLevel, DebugPassManager, nullptr);
+        break;
+      case LLVMRustOptStage::FatLTO:
+        MPM = PB.buildLTODefaultPipeline(OptLevel, DebugPassManager, nullptr);
+        break;
+      }
+    }
+  }
+
+  if (UseThinLTOBuffers) {
+    MPM.addPass(CanonicalizeAliasesPass());
+    MPM.addPass(NameAnonGlobalPass());
+  }
+
+  // Upgrade all calls to old intrinsics first.
+  for (Module::iterator I = TheModule->begin(), E = TheModule->end(); I != E;)
+    UpgradeCallsToIntrinsic(&*I++); // must be post-increment, as we remove
+
+  MPM.run(*TheModule, MAM);
+#else
+  // The new pass manager has been available for a long time,
+  // but we don't bother supporting it on old LLVM versions.
+  report_fatal_error("New pass manager only supported since LLVM 9");
+#endif
+}
+
+// Callback to demangle function name
+// Parameters:
+// * name to be demangled
+// * name len
+// * output buffer
+// * output buffer len
+// Returns len of demangled string, or 0 if demangle failed.
+typedef size_t (*DemangleFn)(const char*, size_t, char*, size_t);
+
+
+namespace {
+
+class RustAssemblyAnnotationWriter : public AssemblyAnnotationWriter {
+  DemangleFn Demangle;
+  std::vector<char> Buf;
+
+public:
+  RustAssemblyAnnotationWriter(DemangleFn Demangle) : Demangle(Demangle) {}
+
+  // Return empty string if demangle failed
+  // or if name does not need to be demangled
+  StringRef CallDemangle(StringRef name) {
+    if (!Demangle) {
+      return StringRef();
+    }
+
+    if (Buf.size() < name.size() * 2) {
+      // Semangled name usually shorter than mangled,
+      // but allocate twice as much memory just in case
+      Buf.resize(name.size() * 2);
+    }
+
+    auto R = Demangle(name.data(), name.size(), Buf.data(), Buf.size());
+    if (!R) {
+      // Demangle failed.
+      return StringRef();
+    }
+
+    auto Demangled = StringRef(Buf.data(), R);
+    if (Demangled == name) {
+      // Do not print anything if demangled name is equal to mangled.
+      return StringRef();
+    }
+
+    return Demangled;
+  }
+
+  void emitFunctionAnnot(const Function *F,
+                         formatted_raw_ostream &OS) override {
+    StringRef Demangled = CallDemangle(F->getName());
+    if (Demangled.empty()) {
+        return;
+    }
+
+    OS << "; " << Demangled << "\n";
+  }
+
+  void emitInstructionAnnot(const Instruction *I,
+                            formatted_raw_ostream &OS) override {
+    const char *Name;
+    const Value *Value;
+    if (const CallInst *CI = dyn_cast<CallInst>(I)) {
+      Name = "call";
+      Value = CI->getCalledOperand();
+    } else if (const InvokeInst* II = dyn_cast<InvokeInst>(I)) {
+      Name = "invoke";
+      Value = II->getCalledOperand();
+    } else {
+      // Could demangle more operations, e. g.
+      // `store %place, @function`.
+      return;
+    }
+
+    if (!Value->hasName()) {
+      return;
+    }
+
+    StringRef Demangled = CallDemangle(Value->getName());
+    if (Demangled.empty()) {
+      return;
+    }
+
+    OS << "; " << Name << " " << Demangled << "\n";
+  }
+};
+
+} // namespace
+
+extern "C" LLVMRustResult
+LLVMRustPrintModule(LLVMModuleRef M, const char *Path, DemangleFn Demangle) {
+  std::string ErrorInfo;
+  std::error_code EC;
+  raw_fd_ostream OS(Path, EC, sys::fs::F_None);
+  if (EC)
+    ErrorInfo = EC.message();
+  if (ErrorInfo != "") {
+    LLVMRustSetLastError(ErrorInfo.c_str());
+    return LLVMRustResult::Failure;
+  }
+
+  RustAssemblyAnnotationWriter AAW(Demangle);
+  formatted_raw_ostream FOS(OS);
+  unwrap(M)->print(FOS, &AAW);
+
+  return LLVMRustResult::Success;
+}
+
+extern "C" void LLVMRustPrintPasses() {
+  LLVMInitializePasses();
+  struct MyListener : PassRegistrationListener {
+    void passEnumerate(const PassInfo *Info) {
+      StringRef PassArg = Info->getPassArgument();
+      StringRef PassName = Info->getPassName();
+      if (!PassArg.empty()) {
+        // These unsigned->signed casts could theoretically overflow, but
+        // realistically never will (and even if, the result is implementation
+        // defined rather plain UB).
+        printf("%15.*s - %.*s\n", (int)PassArg.size(), PassArg.data(),
+               (int)PassName.size(), PassName.data());
+      }
+    }
+  } Listener;
+
+  PassRegistry *PR = PassRegistry::getPassRegistry();
+  PR->enumerateWith(&Listener);
+}
+
+extern "C" void LLVMRustAddAlwaysInlinePass(LLVMPassManagerBuilderRef PMBR,
+                                            bool AddLifetimes) {
+  unwrap(PMBR)->Inliner = llvm::createAlwaysInlinerLegacyPass(AddLifetimes);
+}
+
+extern "C" void LLVMRustRunRestrictionPass(LLVMModuleRef M, char **Symbols,
+                                           size_t Len) {
+  llvm::legacy::PassManager passes;
+
+  auto PreserveFunctions = [=](const GlobalValue &GV) {
+    for (size_t I = 0; I < Len; I++) {
+      if (GV.getName() == Symbols[I]) {
+        return true;
+      }
+    }
+    return false;
+  };
+
+  passes.add(llvm::createInternalizePass(PreserveFunctions));
+
+  passes.run(*unwrap(M));
+}
+
+extern "C" void LLVMRustMarkAllFunctionsNounwind(LLVMModuleRef M) {
+  for (Module::iterator GV = unwrap(M)->begin(), E = unwrap(M)->end(); GV != E;
+       ++GV) {
+    GV->setDoesNotThrow();
+    Function *F = dyn_cast<Function>(GV);
+    if (F == nullptr)
+      continue;
+
+    for (Function::iterator B = F->begin(), BE = F->end(); B != BE; ++B) {
+      for (BasicBlock::iterator I = B->begin(), IE = B->end(); I != IE; ++I) {
+        if (isa<InvokeInst>(I)) {
+          InvokeInst *CI = cast<InvokeInst>(I);
+          CI->setDoesNotThrow();
+        }
+      }
+    }
+  }
+}
+
+extern "C" void
+LLVMRustSetDataLayoutFromTargetMachine(LLVMModuleRef Module,
+                                       LLVMTargetMachineRef TMR) {
+  TargetMachine *Target = unwrap(TMR);
+  unwrap(Module)->setDataLayout(Target->createDataLayout());
+}
+
+extern "C" void LLVMRustSetModulePICLevel(LLVMModuleRef M) {
+  unwrap(M)->setPICLevel(PICLevel::Level::BigPIC);
+}
+
+extern "C" void LLVMRustSetModulePIELevel(LLVMModuleRef M) {
+  unwrap(M)->setPIELevel(PIELevel::Level::Large);
+}
+
+// Here you'll find an implementation of ThinLTO as used by the Rust compiler
+// right now. This ThinLTO support is only enabled on "recent ish" versions of
+// LLVM, and otherwise it's just blanket rejected from other compilers.
+//
+// Most of this implementation is straight copied from LLVM. At the time of
+// this writing it wasn't *quite* suitable to reuse more code from upstream
+// for our purposes, but we should strive to upstream this support once it's
+// ready to go! I figure we may want a bit of testing locally first before
+// sending this upstream to LLVM. I hear though they're quite eager to receive
+// feedback like this!
+//
+// If you're reading this code and wondering "what in the world" or you're
+// working "good lord by LLVM upgrade is *still* failing due to these bindings"
+// then fear not! (ok maybe fear a little). All code here is mostly based
+// on `lib/LTO/ThinLTOCodeGenerator.cpp` in LLVM.
+//
+// You'll find that the general layout here roughly corresponds to the `run`
+// method in that file as well as `ProcessThinLTOModule`. Functions are
+// specifically commented below as well, but if you're updating this code
+// or otherwise trying to understand it, the LLVM source will be useful in
+// interpreting the mysteries within.
+//
+// Otherwise I'll apologize in advance, it probably requires a relatively
+// significant investment on your part to "truly understand" what's going on
+// here. Not saying I do myself, but it took me awhile staring at LLVM's source
+// and various online resources about ThinLTO to make heads or tails of all
+// this.
+
+// This is a shared data structure which *must* be threadsafe to share
+// read-only amongst threads. This also corresponds basically to the arguments
+// of the `ProcessThinLTOModule` function in the LLVM source.
+struct LLVMRustThinLTOData {
+  // The combined index that is the global analysis over all modules we're
+  // performing ThinLTO for. This is mostly managed by LLVM.
+  ModuleSummaryIndex Index;
+
+  // All modules we may look at, stored as in-memory serialized versions. This
+  // is later used when inlining to ensure we can extract any module to inline
+  // from.
+  StringMap<MemoryBufferRef> ModuleMap;
+
+  // A set that we manage of everything we *don't* want internalized. Note that
+  // this includes all transitive references right now as well, but it may not
+  // always!
+  DenseSet<GlobalValue::GUID> GUIDPreservedSymbols;
+
+  // Not 100% sure what these are, but they impact what's internalized and
+  // what's inlined across modules, I believe.
+  StringMap<FunctionImporter::ImportMapTy> ImportLists;
+  StringMap<FunctionImporter::ExportSetTy> ExportLists;
+  StringMap<GVSummaryMapTy> ModuleToDefinedGVSummaries;
+
+  LLVMRustThinLTOData() : Index(/* HaveGVs = */ false) {}
+};
+
+// Just an argument to the `LLVMRustCreateThinLTOData` function below.
+struct LLVMRustThinLTOModule {
+  const char *identifier;
+  const char *data;
+  size_t len;
+};
+
+// This is copied from `lib/LTO/ThinLTOCodeGenerator.cpp`, not sure what it
+// does.
+static const GlobalValueSummary *
+getFirstDefinitionForLinker(const GlobalValueSummaryList &GVSummaryList) {
+  auto StrongDefForLinker = llvm::find_if(
+      GVSummaryList, [](const std::unique_ptr<GlobalValueSummary> &Summary) {
+        auto Linkage = Summary->linkage();
+        return !GlobalValue::isAvailableExternallyLinkage(Linkage) &&
+               !GlobalValue::isWeakForLinker(Linkage);
+      });
+  if (StrongDefForLinker != GVSummaryList.end())
+    return StrongDefForLinker->get();
+
+  auto FirstDefForLinker = llvm::find_if(
+      GVSummaryList, [](const std::unique_ptr<GlobalValueSummary> &Summary) {
+        auto Linkage = Summary->linkage();
+        return !GlobalValue::isAvailableExternallyLinkage(Linkage);
+      });
+  if (FirstDefForLinker == GVSummaryList.end())
+    return nullptr;
+  return FirstDefForLinker->get();
+}
+
+// The main entry point for creating the global ThinLTO analysis. The structure
+// here is basically the same as before threads are spawned in the `run`
+// function of `lib/LTO/ThinLTOCodeGenerator.cpp`.
+extern "C" LLVMRustThinLTOData*
+LLVMRustCreateThinLTOData(LLVMRustThinLTOModule *modules,
+                          int num_modules,
+                          const char **preserved_symbols,
+                          int num_symbols) {
+#if LLVM_VERSION_GE(10, 0)
+  auto Ret = std::make_unique<LLVMRustThinLTOData>();
+#else
+  auto Ret = llvm::make_unique<LLVMRustThinLTOData>();
+#endif
+
+  // Load each module's summary and merge it into one combined index
+  for (int i = 0; i < num_modules; i++) {
+    auto module = &modules[i];
+    StringRef buffer(module->data, module->len);
+    MemoryBufferRef mem_buffer(buffer, module->identifier);
+
+    Ret->ModuleMap[module->identifier] = mem_buffer;
+
+    if (Error Err = readModuleSummaryIndex(mem_buffer, Ret->Index, i)) {
+      LLVMRustSetLastError(toString(std::move(Err)).c_str());
+      return nullptr;
+    }
+  }
+
+  // Collect for each module the list of function it defines (GUID -> Summary)
+  Ret->Index.collectDefinedGVSummariesPerModule(Ret->ModuleToDefinedGVSummaries);
+
+  // Convert the preserved symbols set from string to GUID, this is then needed
+  // for internalization.
+  for (int i = 0; i < num_symbols; i++) {
+    auto GUID = GlobalValue::getGUID(preserved_symbols[i]);
+    Ret->GUIDPreservedSymbols.insert(GUID);
+  }
+
+  // Collect the import/export lists for all modules from the call-graph in the
+  // combined index
+  //
+  // This is copied from `lib/LTO/ThinLTOCodeGenerator.cpp`
+  auto deadIsPrevailing = [&](GlobalValue::GUID G) {
+    return PrevailingType::Unknown;
+  };
+  // We don't have a complete picture in our use of ThinLTO, just our immediate
+  // crate, so we need `ImportEnabled = false` to limit internalization.
+  // Otherwise, we sometimes lose `static` values -- see #60184.
+  computeDeadSymbolsWithConstProp(Ret->Index, Ret->GUIDPreservedSymbols,
+                                  deadIsPrevailing, /* ImportEnabled = */ false);
+  ComputeCrossModuleImport(
+    Ret->Index,
+    Ret->ModuleToDefinedGVSummaries,
+    Ret->ImportLists,
+    Ret->ExportLists
+  );
+
+  // Resolve LinkOnce/Weak symbols, this has to be computed early be cause it
+  // impacts the caching.
+  //
+  // This is copied from `lib/LTO/ThinLTOCodeGenerator.cpp` with some of this
+  // being lifted from `lib/LTO/LTO.cpp` as well
+  StringMap<std::map<GlobalValue::GUID, GlobalValue::LinkageTypes>> ResolvedODR;
+  DenseMap<GlobalValue::GUID, const GlobalValueSummary *> PrevailingCopy;
+  for (auto &I : Ret->Index) {
+    if (I.second.SummaryList.size() > 1)
+      PrevailingCopy[I.first] = getFirstDefinitionForLinker(I.second.SummaryList);
+  }
+  auto isPrevailing = [&](GlobalValue::GUID GUID, const GlobalValueSummary *S) {
+    const auto &Prevailing = PrevailingCopy.find(GUID);
+    if (Prevailing == PrevailingCopy.end())
+      return true;
+    return Prevailing->second == S;
+  };
+  auto recordNewLinkage = [&](StringRef ModuleIdentifier,
+                              GlobalValue::GUID GUID,
+                              GlobalValue::LinkageTypes NewLinkage) {
+    ResolvedODR[ModuleIdentifier][GUID] = NewLinkage;
+  };
+#if LLVM_VERSION_GE(9, 0)
+  thinLTOResolvePrevailingInIndex(Ret->Index, isPrevailing, recordNewLinkage,
+                                  Ret->GUIDPreservedSymbols);
+#else
+  thinLTOResolvePrevailingInIndex(Ret->Index, isPrevailing, recordNewLinkage);
+#endif
+
+  // Here we calculate an `ExportedGUIDs` set for use in the `isExported`
+  // callback below. This callback below will dictate the linkage for all
+  // summaries in the index, and we basically just only want to ensure that dead
+  // symbols are internalized. Otherwise everything that's already external
+  // linkage will stay as external, and internal will stay as internal.
+  std::set<GlobalValue::GUID> ExportedGUIDs;
+  for (auto &List : Ret->Index) {
+    for (auto &GVS: List.second.SummaryList) {
+      if (GlobalValue::isLocalLinkage(GVS->linkage()))
+        continue;
+      auto GUID = GVS->getOriginalName();
+      if (GVS->flags().Live)
+        ExportedGUIDs.insert(GUID);
+    }
+  }
+#if LLVM_VERSION_GE(10, 0)
+  auto isExported = [&](StringRef ModuleIdentifier, ValueInfo VI) {
+    const auto &ExportList = Ret->ExportLists.find(ModuleIdentifier);
+    return (ExportList != Ret->ExportLists.end() &&
+      ExportList->second.count(VI)) ||
+      ExportedGUIDs.count(VI.getGUID());
+  };
+  thinLTOInternalizeAndPromoteInIndex(Ret->Index, isExported, isPrevailing);
+#else
+  auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
+    const auto &ExportList = Ret->ExportLists.find(ModuleIdentifier);
+    return (ExportList != Ret->ExportLists.end() &&
+      ExportList->second.count(GUID)) ||
+      ExportedGUIDs.count(GUID);
+  };
+  thinLTOInternalizeAndPromoteInIndex(Ret->Index, isExported);
+#endif
+
+  return Ret.release();
+}
+
+extern "C" void
+LLVMRustFreeThinLTOData(LLVMRustThinLTOData *Data) {
+  delete Data;
+}
+
+// Below are the various passes that happen *per module* when doing ThinLTO.
+//
+// In other words, these are the functions that are all run concurrently
+// with one another, one per module. The passes here correspond to the analysis
+// passes in `lib/LTO/ThinLTOCodeGenerator.cpp`, currently found in the
+// `ProcessThinLTOModule` function. Here they're split up into separate steps
+// so rustc can save off the intermediate bytecode between each step.
+
+#if LLVM_VERSION_GE(11, 0)
+static bool
+clearDSOLocalOnDeclarations(Module &Mod, TargetMachine &TM) {
+  // When linking an ELF shared object, dso_local should be dropped. We
+  // conservatively do this for -fpic.
+  bool ClearDSOLocalOnDeclarations =
+      TM.getTargetTriple().isOSBinFormatELF() &&
+      TM.getRelocationModel() != Reloc::Static &&
+      Mod.getPIELevel() == PIELevel::Default;
+  return ClearDSOLocalOnDeclarations;
+}
+#endif
+
+extern "C" bool
+LLVMRustPrepareThinLTORename(const LLVMRustThinLTOData *Data, LLVMModuleRef M,
+                             LLVMTargetMachineRef TM) {
+  Module &Mod = *unwrap(M);
+  TargetMachine &Target = *unwrap(TM);
+
+#if LLVM_VERSION_GE(11, 0)
+  bool ClearDSOLocal = clearDSOLocalOnDeclarations(Mod, Target);
+  bool error = renameModuleForThinLTO(Mod, Data->Index, ClearDSOLocal);
+#else
+  bool error = renameModuleForThinLTO(Mod, Data->Index);
+#endif
+
+  if (error) {
+    LLVMRustSetLastError("renameModuleForThinLTO failed");
+    return false;
+  }
+  return true;
+}
+
+extern "C" bool
+LLVMRustPrepareThinLTOResolveWeak(const LLVMRustThinLTOData *Data, LLVMModuleRef M) {
+  Module &Mod = *unwrap(M);
+  const auto &DefinedGlobals = Data->ModuleToDefinedGVSummaries.lookup(Mod.getModuleIdentifier());
+  thinLTOResolvePrevailingInModule(Mod, DefinedGlobals);
+  return true;
+}
+
+extern "C" bool
+LLVMRustPrepareThinLTOInternalize(const LLVMRustThinLTOData *Data, LLVMModuleRef M) {
+  Module &Mod = *unwrap(M);
+  const auto &DefinedGlobals = Data->ModuleToDefinedGVSummaries.lookup(Mod.getModuleIdentifier());
+  thinLTOInternalizeModule(Mod, DefinedGlobals);
+  return true;
+}
+
+extern "C" bool
+LLVMRustPrepareThinLTOImport(const LLVMRustThinLTOData *Data, LLVMModuleRef M,
+                             LLVMTargetMachineRef TM) {
+  Module &Mod = *unwrap(M);
+  TargetMachine &Target = *unwrap(TM);
+
+  const auto &ImportList = Data->ImportLists.lookup(Mod.getModuleIdentifier());
+  auto Loader = [&](StringRef Identifier) {
+    const auto &Memory = Data->ModuleMap.lookup(Identifier);
+    auto &Context = Mod.getContext();
+    auto MOrErr = getLazyBitcodeModule(Memory, Context, true, true);
+
+    if (!MOrErr)
+      return MOrErr;
+
+    // The rest of this closure is a workaround for
+    // https://bugs.llvm.org/show_bug.cgi?id=38184 where during ThinLTO imports
+    // we accidentally import wasm custom sections into different modules,
+    // duplicating them by in the final output artifact.
+    //
+    // The issue is worked around here by manually removing the
+    // `wasm.custom_sections` named metadata node from any imported module. This
+    // we know isn't used by any optimization pass so there's no need for it to
+    // be imported.
+    //
+    // Note that the metadata is currently lazily loaded, so we materialize it
+    // here before looking up if there's metadata inside. The `FunctionImporter`
+    // will immediately materialize metadata anyway after an import, so this
+    // shouldn't be a perf hit.
+    if (Error Err = (*MOrErr)->materializeMetadata()) {
+      Expected<std::unique_ptr<Module>> Ret(std::move(Err));
+      return Ret;
+    }
+
+    auto *WasmCustomSections = (*MOrErr)->getNamedMetadata("wasm.custom_sections");
+    if (WasmCustomSections)
+      WasmCustomSections->eraseFromParent();
+
+    return MOrErr;
+  };
+#if LLVM_VERSION_GE(11, 0)
+  bool ClearDSOLocal = clearDSOLocalOnDeclarations(Mod, Target);
+  FunctionImporter Importer(Data->Index, Loader, ClearDSOLocal);
+#else
+  FunctionImporter Importer(Data->Index, Loader);
+#endif
+  Expected<bool> Result = Importer.importFunctions(Mod, ImportList);
+  if (!Result) {
+    LLVMRustSetLastError(toString(Result.takeError()).c_str());
+    return false;
+  }
+  return true;
+}
+
+extern "C" typedef void (*LLVMRustModuleNameCallback)(void*, // payload
+                                                      const char*, // importing module name
+                                                      const char*); // imported module name
+
+// Calls `module_name_callback` for each module import done by ThinLTO.
+// The callback is provided with regular null-terminated C strings.
+extern "C" void
+LLVMRustGetThinLTOModuleImports(const LLVMRustThinLTOData *data,
+                                LLVMRustModuleNameCallback module_name_callback,
+                                void* callback_payload) {
+  for (const auto& importing_module : data->ImportLists) {
+    const std::string importing_module_id = importing_module.getKey().str();
+    const auto& imports = importing_module.getValue();
+    for (const auto& imported_module : imports) {
+      const std::string imported_module_id = imported_module.getKey().str();
+      module_name_callback(callback_payload,
+                           importing_module_id.c_str(),
+                           imported_module_id.c_str());
+    }
+  }
+}
+
+// This struct and various functions are sort of a hack right now, but the
+// problem is that we've got in-memory LLVM modules after we generate and
+// optimize all codegen-units for one compilation in rustc. To be compatible
+// with the LTO support above we need to serialize the modules plus their
+// ThinLTO summary into memory.
+//
+// This structure is basically an owned version of a serialize module, with
+// a ThinLTO summary attached.
+struct LLVMRustThinLTOBuffer {
+  std::string data;
+};
+
+extern "C" LLVMRustThinLTOBuffer*
+LLVMRustThinLTOBufferCreate(LLVMModuleRef M) {
+#if LLVM_VERSION_GE(10, 0)
+  auto Ret = std::make_unique<LLVMRustThinLTOBuffer>();
+#else
+  auto Ret = llvm::make_unique<LLVMRustThinLTOBuffer>();
+#endif
+  {
+    raw_string_ostream OS(Ret->data);
+    {
+      legacy::PassManager PM;
+      PM.add(createWriteThinLTOBitcodePass(OS));
+      PM.run(*unwrap(M));
+    }
+  }
+  return Ret.release();
+}
+
+extern "C" void
+LLVMRustThinLTOBufferFree(LLVMRustThinLTOBuffer *Buffer) {
+  delete Buffer;
+}
+
+extern "C" const void*
+LLVMRustThinLTOBufferPtr(const LLVMRustThinLTOBuffer *Buffer) {
+  return Buffer->data.data();
+}
+
+extern "C" size_t
+LLVMRustThinLTOBufferLen(const LLVMRustThinLTOBuffer *Buffer) {
+  return Buffer->data.length();
+}
+
+// This is what we used to parse upstream bitcode for actual ThinLTO
+// processing.  We'll call this once per module optimized through ThinLTO, and
+// it'll be called concurrently on many threads.
+extern "C" LLVMModuleRef
+LLVMRustParseBitcodeForLTO(LLVMContextRef Context,
+                           const char *data,
+                           size_t len,
+                           const char *identifier) {
+  StringRef Data(data, len);
+  MemoryBufferRef Buffer(Data, identifier);
+  unwrap(Context)->enableDebugTypeODRUniquing();
+  Expected<std::unique_ptr<Module>> SrcOrError =
+      parseBitcodeFile(Buffer, *unwrap(Context));
+  if (!SrcOrError) {
+    LLVMRustSetLastError(toString(SrcOrError.takeError()).c_str());
+    return nullptr;
+  }
+  return wrap(std::move(*SrcOrError).release());
+}
+
+// Find the bitcode section in the object file data and return it as a slice.
+// Fail if the bitcode section is present but empty.
+//
+// On success, the return value is the pointer to the start of the slice and
+// `out_len` is filled with the (non-zero) length. On failure, the return value
+// is `nullptr` and `out_len` is set to zero.
+extern "C" const char*
+LLVMRustGetBitcodeSliceFromObjectData(const char *data,
+                                      size_t len,
+                                      size_t *out_len) {
+  *out_len = 0;
+
+  StringRef Data(data, len);
+  MemoryBufferRef Buffer(Data, ""); // The id is unused.
+
+  Expected<MemoryBufferRef> BitcodeOrError =
+    object::IRObjectFile::findBitcodeInMemBuffer(Buffer);
+  if (!BitcodeOrError) {
+    LLVMRustSetLastError(toString(BitcodeOrError.takeError()).c_str());
+    return nullptr;
+  }
+
+  *out_len = BitcodeOrError->getBufferSize();
+  return BitcodeOrError->getBufferStart();
+}
+
+// Rewrite all `DICompileUnit` pointers to the `DICompileUnit` specified. See
+// the comment in `back/lto.rs` for why this exists.
+extern "C" void
+LLVMRustThinLTOGetDICompileUnit(LLVMModuleRef Mod,
+                                DICompileUnit **A,
+                                DICompileUnit **B) {
+  Module *M = unwrap(Mod);
+  DICompileUnit **Cur = A;
+  DICompileUnit **Next = B;
+  for (DICompileUnit *CU : M->debug_compile_units()) {
+    *Cur = CU;
+    Cur = Next;
+    Next = nullptr;
+    if (Cur == nullptr)
+      break;
+  }
+}
+
+// Rewrite all `DICompileUnit` pointers to the `DICompileUnit` specified. See
+// the comment in `back/lto.rs` for why this exists.
+extern "C" void
+LLVMRustThinLTOPatchDICompileUnit(LLVMModuleRef Mod, DICompileUnit *Unit) {
+  Module *M = unwrap(Mod);
+
+  // If the original source module didn't have a `DICompileUnit` then try to
+  // merge all the existing compile units. If there aren't actually any though
+  // then there's not much for us to do so return.
+  if (Unit == nullptr) {
+    for (DICompileUnit *CU : M->debug_compile_units()) {
+      Unit = CU;
+      break;
+    }
+    if (Unit == nullptr)
+      return;
+  }
+
+  // Use LLVM's built-in `DebugInfoFinder` to find a bunch of debuginfo and
+  // process it recursively. Note that we used to specifically iterate over
+  // instructions to ensure we feed everything into it, but `processModule`
+  // started doing this the same way in LLVM 7 (commit d769eb36ab2b8).
+  DebugInfoFinder Finder;
+  Finder.processModule(*M);
+
+  // After we've found all our debuginfo, rewrite all subprograms to point to
+  // the same `DICompileUnit`.
+  for (auto &F : Finder.subprograms()) {
+    F->replaceUnit(Unit);
+  }
+
+  // Erase any other references to other `DICompileUnit` instances, the verifier
+  // will later ensure that we don't actually have any other stale references to
+  // worry about.
+  auto *MD = M->getNamedMetadata("llvm.dbg.cu");
+  MD->clearOperands();
+  MD->addOperand(Unit);
+}
diff --git a/compiler/rustc_llvm/llvm-wrapper/README b/compiler/rustc_llvm/llvm-wrapper/README
new file mode 100644
index 00000000000..e1c6dd07d2b
--- /dev/null
+++ b/compiler/rustc_llvm/llvm-wrapper/README
@@ -0,0 +1,16 @@
+This directory currently contains some LLVM support code. This will generally
+be sent upstream to LLVM in time; for now it lives here.
+
+NOTE: the LLVM C++ ABI is subject to between-version breakage and must *never*
+be exposed to Rust. To allow for easy auditing of that, all Rust-exposed types
+must be typedef-ed as "LLVMXyz", or "LLVMRustXyz" if they were defined here.
+
+Functions that return a failure status and leave the error in
+the LLVM last error should return an LLVMRustResult rather than an
+int or anything to avoid confusion.
+
+When translating enums, add a single `Other` variant as the first
+one to allow for new variants to be added. It should abort when used
+as an input.
+
+All other types must not be typedef-ed as such.
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
new file mode 100644
index 00000000000..e85a9b76380
--- /dev/null
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -0,0 +1,1721 @@
+#include "LLVMWrapper.h"
+#include "llvm/IR/DebugInfoMetadata.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/DiagnosticPrinter.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/Object/Archive.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Bitcode/BitcodeWriterPass.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/ADT/Optional.h"
+
+#include <iostream>
+
+//===----------------------------------------------------------------------===
+//
+// This file defines alternate interfaces to core functions that are more
+// readily callable by Rust's FFI.
+//
+//===----------------------------------------------------------------------===
+
+using namespace llvm;
+using namespace llvm::sys;
+using namespace llvm::object;
+
+// LLVMAtomicOrdering is already an enum - don't create another
+// one.
+static AtomicOrdering fromRust(LLVMAtomicOrdering Ordering) {
+  switch (Ordering) {
+  case LLVMAtomicOrderingNotAtomic:
+    return AtomicOrdering::NotAtomic;
+  case LLVMAtomicOrderingUnordered:
+    return AtomicOrdering::Unordered;
+  case LLVMAtomicOrderingMonotonic:
+    return AtomicOrdering::Monotonic;
+  case LLVMAtomicOrderingAcquire:
+    return AtomicOrdering::Acquire;
+  case LLVMAtomicOrderingRelease:
+    return AtomicOrdering::Release;
+  case LLVMAtomicOrderingAcquireRelease:
+    return AtomicOrdering::AcquireRelease;
+  case LLVMAtomicOrderingSequentiallyConsistent:
+    return AtomicOrdering::SequentiallyConsistent;
+  }
+
+  report_fatal_error("Invalid LLVMAtomicOrdering value!");
+}
+
+static LLVM_THREAD_LOCAL char *LastError;
+
+// Custom error handler for fatal LLVM errors.
+//
+// Notably it exits the process with code 101, unlike LLVM's default of 1.
+static void FatalErrorHandler(void *UserData,
+                              const std::string& Reason,
+                              bool GenCrashDiag) {
+  // Do the same thing that the default error handler does.
+  std::cerr << "LLVM ERROR: " << Reason << std::endl;
+
+  // Since this error handler exits the process, we have to run any cleanup that
+  // LLVM would run after handling the error. This might change with an LLVM
+  // upgrade.
+  sys::RunInterruptHandlers();
+
+  exit(101);
+}
+
+extern "C" void LLVMRustInstallFatalErrorHandler() {
+  install_fatal_error_handler(FatalErrorHandler);
+}
+
+extern "C" LLVMMemoryBufferRef
+LLVMRustCreateMemoryBufferWithContentsOfFile(const char *Path) {
+  ErrorOr<std::unique_ptr<MemoryBuffer>> BufOr =
+      MemoryBuffer::getFile(Path, -1, false);
+  if (!BufOr) {
+    LLVMRustSetLastError(BufOr.getError().message().c_str());
+    return nullptr;
+  }
+  return wrap(BufOr.get().release());
+}
+
+extern "C" char *LLVMRustGetLastError(void) {
+  char *Ret = LastError;
+  LastError = nullptr;
+  return Ret;
+}
+
+extern "C" unsigned int LLVMRustGetInstructionCount(LLVMModuleRef M) {
+  return unwrap(M)->getInstructionCount();
+}
+
+extern "C" void LLVMRustSetLastError(const char *Err) {
+  free((void *)LastError);
+  LastError = strdup(Err);
+}
+
+extern "C" LLVMContextRef LLVMRustContextCreate(bool shouldDiscardNames) {
+  auto ctx = new LLVMContext();
+  ctx->setDiscardValueNames(shouldDiscardNames);
+  return wrap(ctx);
+}
+
+extern "C" void LLVMRustSetNormalizedTarget(LLVMModuleRef M,
+                                            const char *Triple) {
+  unwrap(M)->setTargetTriple(Triple::normalize(Triple));
+}
+
+extern "C" void LLVMRustPrintPassTimings() {
+  raw_fd_ostream OS(2, false); // stderr.
+  TimerGroup::printAll(OS);
+}
+
+extern "C" LLVMValueRef LLVMRustGetNamedValue(LLVMModuleRef M, const char *Name,
+                                              size_t NameLen) {
+  return wrap(unwrap(M)->getNamedValue(StringRef(Name, NameLen)));
+}
+
+extern "C" LLVMValueRef LLVMRustGetOrInsertFunction(LLVMModuleRef M,
+                                                    const char *Name,
+                                                    size_t NameLen,
+                                                    LLVMTypeRef FunctionTy) {
+  return wrap(unwrap(M)
+                  ->getOrInsertFunction(StringRef(Name, NameLen),
+                                        unwrap<FunctionType>(FunctionTy))
+#if LLVM_VERSION_GE(9, 0)
+                  .getCallee()
+#endif
+  );
+}
+
+extern "C" LLVMValueRef
+LLVMRustGetOrInsertGlobal(LLVMModuleRef M, const char *Name, size_t NameLen, LLVMTypeRef Ty) {
+  StringRef NameRef(Name, NameLen);
+  return wrap(unwrap(M)->getOrInsertGlobal(NameRef, unwrap(Ty)));
+}
+
+extern "C" LLVMValueRef
+LLVMRustInsertPrivateGlobal(LLVMModuleRef M, LLVMTypeRef Ty) {
+  return wrap(new GlobalVariable(*unwrap(M),
+                                 unwrap(Ty),
+                                 false,
+                                 GlobalValue::PrivateLinkage,
+                                 nullptr));
+}
+
+extern "C" LLVMTypeRef LLVMRustMetadataTypeInContext(LLVMContextRef C) {
+  return wrap(Type::getMetadataTy(*unwrap(C)));
+}
+
+static Attribute::AttrKind fromRust(LLVMRustAttribute Kind) {
+  switch (Kind) {
+  case AlwaysInline:
+    return Attribute::AlwaysInline;
+  case ByVal:
+    return Attribute::ByVal;
+  case Cold:
+    return Attribute::Cold;
+  case InlineHint:
+    return Attribute::InlineHint;
+  case MinSize:
+    return Attribute::MinSize;
+  case Naked:
+    return Attribute::Naked;
+  case NoAlias:
+    return Attribute::NoAlias;
+  case NoCapture:
+    return Attribute::NoCapture;
+  case NoInline:
+    return Attribute::NoInline;
+  case NonNull:
+    return Attribute::NonNull;
+  case NoRedZone:
+    return Attribute::NoRedZone;
+  case NoReturn:
+    return Attribute::NoReturn;
+  case NoUnwind:
+    return Attribute::NoUnwind;
+  case OptimizeForSize:
+    return Attribute::OptimizeForSize;
+  case ReadOnly:
+    return Attribute::ReadOnly;
+  case SExt:
+    return Attribute::SExt;
+  case StructRet:
+    return Attribute::StructRet;
+  case UWTable:
+    return Attribute::UWTable;
+  case ZExt:
+    return Attribute::ZExt;
+  case InReg:
+    return Attribute::InReg;
+  case SanitizeThread:
+    return Attribute::SanitizeThread;
+  case SanitizeAddress:
+    return Attribute::SanitizeAddress;
+  case SanitizeMemory:
+    return Attribute::SanitizeMemory;
+  case NonLazyBind:
+    return Attribute::NonLazyBind;
+  case OptimizeNone:
+    return Attribute::OptimizeNone;
+  case ReturnsTwice:
+    return Attribute::ReturnsTwice;
+  case ReadNone:
+    return Attribute::ReadNone;
+  case InaccessibleMemOnly:
+    return Attribute::InaccessibleMemOnly;
+  }
+  report_fatal_error("bad AttributeKind");
+}
+
+extern "C" void LLVMRustAddCallSiteAttribute(LLVMValueRef Instr, unsigned Index,
+                                             LLVMRustAttribute RustAttr) {
+  CallBase *Call = unwrap<CallBase>(Instr);
+  Attribute Attr = Attribute::get(Call->getContext(), fromRust(RustAttr));
+  Call->addAttribute(Index, Attr);
+}
+
+extern "C" void LLVMRustAddAlignmentCallSiteAttr(LLVMValueRef Instr,
+                                                 unsigned Index,
+                                                 uint32_t Bytes) {
+  CallBase *Call = unwrap<CallBase>(Instr);
+  AttrBuilder B;
+  B.addAlignmentAttr(Bytes);
+  Call->setAttributes(Call->getAttributes().addAttributes(
+      Call->getContext(), Index, B));
+}
+
+extern "C" void LLVMRustAddDereferenceableCallSiteAttr(LLVMValueRef Instr,
+                                                       unsigned Index,
+                                                       uint64_t Bytes) {
+  CallBase *Call = unwrap<CallBase>(Instr);
+  AttrBuilder B;
+  B.addDereferenceableAttr(Bytes);
+  Call->setAttributes(Call->getAttributes().addAttributes(
+      Call->getContext(), Index, B));
+}
+
+extern "C" void LLVMRustAddDereferenceableOrNullCallSiteAttr(LLVMValueRef Instr,
+                                                             unsigned Index,
+                                                             uint64_t Bytes) {
+  CallBase *Call = unwrap<CallBase>(Instr);
+  AttrBuilder B;
+  B.addDereferenceableOrNullAttr(Bytes);
+  Call->setAttributes(Call->getAttributes().addAttributes(
+      Call->getContext(), Index, B));
+}
+
+extern "C" void LLVMRustAddByValCallSiteAttr(LLVMValueRef Instr, unsigned Index,
+                                             LLVMTypeRef Ty) {
+  CallBase *Call = unwrap<CallBase>(Instr);
+#if LLVM_VERSION_GE(9, 0)
+  Attribute Attr = Attribute::getWithByValType(Call->getContext(), unwrap(Ty));
+#else
+  Attribute Attr = Attribute::get(Call->getContext(), Attribute::ByVal);
+#endif
+  Call->addAttribute(Index, Attr);
+}
+
+extern "C" void LLVMRustAddFunctionAttribute(LLVMValueRef Fn, unsigned Index,
+                                             LLVMRustAttribute RustAttr) {
+  Function *A = unwrap<Function>(Fn);
+  Attribute Attr = Attribute::get(A->getContext(), fromRust(RustAttr));
+  AttrBuilder B(Attr);
+  A->addAttributes(Index, B);
+}
+
+extern "C" void LLVMRustAddAlignmentAttr(LLVMValueRef Fn,
+                                         unsigned Index,
+                                         uint32_t Bytes) {
+  Function *A = unwrap<Function>(Fn);
+  AttrBuilder B;
+  B.addAlignmentAttr(Bytes);
+  A->addAttributes(Index, B);
+}
+
+extern "C" void LLVMRustAddDereferenceableAttr(LLVMValueRef Fn, unsigned Index,
+                                               uint64_t Bytes) {
+  Function *A = unwrap<Function>(Fn);
+  AttrBuilder B;
+  B.addDereferenceableAttr(Bytes);
+  A->addAttributes(Index, B);
+}
+
+extern "C" void LLVMRustAddDereferenceableOrNullAttr(LLVMValueRef Fn,
+                                                     unsigned Index,
+                                                     uint64_t Bytes) {
+  Function *A = unwrap<Function>(Fn);
+  AttrBuilder B;
+  B.addDereferenceableOrNullAttr(Bytes);
+  A->addAttributes(Index, B);
+}
+
+extern "C" void LLVMRustAddByValAttr(LLVMValueRef Fn, unsigned Index,
+                                     LLVMTypeRef Ty) {
+  Function *F = unwrap<Function>(Fn);
+#if LLVM_VERSION_GE(9, 0)
+  Attribute Attr = Attribute::getWithByValType(F->getContext(), unwrap(Ty));
+#else
+  Attribute Attr = Attribute::get(F->getContext(), Attribute::ByVal);
+#endif
+  F->addAttribute(Index, Attr);
+}
+
+extern "C" void LLVMRustAddFunctionAttrStringValue(LLVMValueRef Fn,
+                                                   unsigned Index,
+                                                   const char *Name,
+                                                   const char *Value) {
+  Function *F = unwrap<Function>(Fn);
+  AttrBuilder B;
+  B.addAttribute(Name, Value);
+  F->addAttributes(Index, B);
+}
+
+extern "C" void LLVMRustRemoveFunctionAttributes(LLVMValueRef Fn,
+                                                 unsigned Index,
+                                                 LLVMRustAttribute RustAttr) {
+  Function *F = unwrap<Function>(Fn);
+  Attribute Attr = Attribute::get(F->getContext(), fromRust(RustAttr));
+  AttrBuilder B(Attr);
+  auto PAL = F->getAttributes();
+  auto PALNew = PAL.removeAttributes(F->getContext(), Index, B);
+  F->setAttributes(PALNew);
+}
+
+// enable fpmath flag UnsafeAlgebra
+extern "C" void LLVMRustSetHasUnsafeAlgebra(LLVMValueRef V) {
+  if (auto I = dyn_cast<Instruction>(unwrap<Value>(V))) {
+    I->setFast(true);
+  }
+}
+
+extern "C" LLVMValueRef
+LLVMRustBuildAtomicLoad(LLVMBuilderRef B, LLVMValueRef Source, const char *Name,
+                        LLVMAtomicOrdering Order) {
+  Value *Ptr = unwrap(Source);
+  Type *Ty = Ptr->getType()->getPointerElementType();
+  LoadInst *LI = unwrap(B)->CreateLoad(Ty, Ptr, Name);
+  LI->setAtomic(fromRust(Order));
+  return wrap(LI);
+}
+
+extern "C" LLVMValueRef LLVMRustBuildAtomicStore(LLVMBuilderRef B,
+                                                 LLVMValueRef V,
+                                                 LLVMValueRef Target,
+                                                 LLVMAtomicOrdering Order) {
+  StoreInst *SI = unwrap(B)->CreateStore(unwrap(V), unwrap(Target));
+  SI->setAtomic(fromRust(Order));
+  return wrap(SI);
+}
+
+// FIXME: Use the C-API LLVMBuildAtomicCmpXchg and LLVMSetWeak
+// once we raise our minimum support to LLVM 10.
+extern "C" LLVMValueRef
+LLVMRustBuildAtomicCmpXchg(LLVMBuilderRef B, LLVMValueRef Target,
+                           LLVMValueRef Old, LLVMValueRef Source,
+                           LLVMAtomicOrdering Order,
+                           LLVMAtomicOrdering FailureOrder, LLVMBool Weak) {
+  AtomicCmpXchgInst *ACXI = unwrap(B)->CreateAtomicCmpXchg(
+      unwrap(Target), unwrap(Old), unwrap(Source), fromRust(Order),
+      fromRust(FailureOrder));
+  ACXI->setWeak(Weak);
+  return wrap(ACXI);
+}
+
+enum class LLVMRustSynchronizationScope {
+  SingleThread,
+  CrossThread,
+};
+
+static SyncScope::ID fromRust(LLVMRustSynchronizationScope Scope) {
+  switch (Scope) {
+  case LLVMRustSynchronizationScope::SingleThread:
+    return SyncScope::SingleThread;
+  case LLVMRustSynchronizationScope::CrossThread:
+    return SyncScope::System;
+  default:
+    report_fatal_error("bad SynchronizationScope.");
+  }
+}
+
+extern "C" LLVMValueRef
+LLVMRustBuildAtomicFence(LLVMBuilderRef B, LLVMAtomicOrdering Order,
+                         LLVMRustSynchronizationScope Scope) {
+  return wrap(unwrap(B)->CreateFence(fromRust(Order), fromRust(Scope)));
+}
+
+enum class LLVMRustAsmDialect {
+  Att,
+  Intel,
+};
+
+static InlineAsm::AsmDialect fromRust(LLVMRustAsmDialect Dialect) {
+  switch (Dialect) {
+  case LLVMRustAsmDialect::Att:
+    return InlineAsm::AD_ATT;
+  case LLVMRustAsmDialect::Intel:
+    return InlineAsm::AD_Intel;
+  default:
+    report_fatal_error("bad AsmDialect.");
+  }
+}
+
+extern "C" LLVMValueRef
+LLVMRustInlineAsm(LLVMTypeRef Ty, char *AsmString, size_t AsmStringLen,
+                  char *Constraints, size_t ConstraintsLen,
+                  LLVMBool HasSideEffects, LLVMBool IsAlignStack,
+                  LLVMRustAsmDialect Dialect) {
+  return wrap(InlineAsm::get(unwrap<FunctionType>(Ty),
+                             StringRef(AsmString, AsmStringLen),
+                             StringRef(Constraints, ConstraintsLen),
+                             HasSideEffects, IsAlignStack, fromRust(Dialect)));
+}
+
+extern "C" bool LLVMRustInlineAsmVerify(LLVMTypeRef Ty, char *Constraints,
+                                        size_t ConstraintsLen) {
+  return InlineAsm::Verify(unwrap<FunctionType>(Ty),
+                           StringRef(Constraints, ConstraintsLen));
+}
+
+extern "C" void LLVMRustAppendModuleInlineAsm(LLVMModuleRef M, const char *Asm,
+                                              size_t AsmLen) {
+  unwrap(M)->appendModuleInlineAsm(StringRef(Asm, AsmLen));
+}
+
+typedef DIBuilder *LLVMRustDIBuilderRef;
+
+template <typename DIT> DIT *unwrapDIPtr(LLVMMetadataRef Ref) {
+  return (DIT *)(Ref ? unwrap<MDNode>(Ref) : nullptr);
+}
+
+#define DIDescriptor DIScope
+#define DIArray DINodeArray
+#define unwrapDI unwrapDIPtr
+
+// These values **must** match debuginfo::DIFlags! They also *happen*
+// to match LLVM, but that isn't required as we do giant sets of
+// matching below. The value shouldn't be directly passed to LLVM.
+enum class LLVMRustDIFlags : uint32_t {
+  FlagZero = 0,
+  FlagPrivate = 1,
+  FlagProtected = 2,
+  FlagPublic = 3,
+  FlagFwdDecl = (1 << 2),
+  FlagAppleBlock = (1 << 3),
+  FlagBlockByrefStruct = (1 << 4),
+  FlagVirtual = (1 << 5),
+  FlagArtificial = (1 << 6),
+  FlagExplicit = (1 << 7),
+  FlagPrototyped = (1 << 8),
+  FlagObjcClassComplete = (1 << 9),
+  FlagObjectPointer = (1 << 10),
+  FlagVector = (1 << 11),
+  FlagStaticMember = (1 << 12),
+  FlagLValueReference = (1 << 13),
+  FlagRValueReference = (1 << 14),
+  FlagExternalTypeRef = (1 << 15),
+  FlagIntroducedVirtual = (1 << 18),
+  FlagBitField = (1 << 19),
+  FlagNoReturn = (1 << 20),
+  // Do not add values that are not supported by the minimum LLVM
+  // version we support! see llvm/include/llvm/IR/DebugInfoFlags.def
+};
+
+inline LLVMRustDIFlags operator&(LLVMRustDIFlags A, LLVMRustDIFlags B) {
+  return static_cast<LLVMRustDIFlags>(static_cast<uint32_t>(A) &
+                                      static_cast<uint32_t>(B));
+}
+
+inline LLVMRustDIFlags operator|(LLVMRustDIFlags A, LLVMRustDIFlags B) {
+  return static_cast<LLVMRustDIFlags>(static_cast<uint32_t>(A) |
+                                      static_cast<uint32_t>(B));
+}
+
+inline LLVMRustDIFlags &operator|=(LLVMRustDIFlags &A, LLVMRustDIFlags B) {
+  return A = A | B;
+}
+
+inline bool isSet(LLVMRustDIFlags F) { return F != LLVMRustDIFlags::FlagZero; }
+
+inline LLVMRustDIFlags visibility(LLVMRustDIFlags F) {
+  return static_cast<LLVMRustDIFlags>(static_cast<uint32_t>(F) & 0x3);
+}
+
+static DINode::DIFlags fromRust(LLVMRustDIFlags Flags) {
+  DINode::DIFlags Result = DINode::DIFlags::FlagZero;
+
+  switch (visibility(Flags)) {
+  case LLVMRustDIFlags::FlagPrivate:
+    Result |= DINode::DIFlags::FlagPrivate;
+    break;
+  case LLVMRustDIFlags::FlagProtected:
+    Result |= DINode::DIFlags::FlagProtected;
+    break;
+  case LLVMRustDIFlags::FlagPublic:
+    Result |= DINode::DIFlags::FlagPublic;
+    break;
+  default:
+    // The rest are handled below
+    break;
+  }
+
+  if (isSet(Flags & LLVMRustDIFlags::FlagFwdDecl)) {
+    Result |= DINode::DIFlags::FlagFwdDecl;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagAppleBlock)) {
+    Result |= DINode::DIFlags::FlagAppleBlock;
+  }
+#if LLVM_VERSION_LT(10, 0)
+  if (isSet(Flags & LLVMRustDIFlags::FlagBlockByrefStruct)) {
+    Result |= DINode::DIFlags::FlagBlockByrefStruct;
+  }
+#endif
+  if (isSet(Flags & LLVMRustDIFlags::FlagVirtual)) {
+    Result |= DINode::DIFlags::FlagVirtual;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagArtificial)) {
+    Result |= DINode::DIFlags::FlagArtificial;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagExplicit)) {
+    Result |= DINode::DIFlags::FlagExplicit;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagPrototyped)) {
+    Result |= DINode::DIFlags::FlagPrototyped;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagObjcClassComplete)) {
+    Result |= DINode::DIFlags::FlagObjcClassComplete;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagObjectPointer)) {
+    Result |= DINode::DIFlags::FlagObjectPointer;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagVector)) {
+    Result |= DINode::DIFlags::FlagVector;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagStaticMember)) {
+    Result |= DINode::DIFlags::FlagStaticMember;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagLValueReference)) {
+    Result |= DINode::DIFlags::FlagLValueReference;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagRValueReference)) {
+    Result |= DINode::DIFlags::FlagRValueReference;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagIntroducedVirtual)) {
+    Result |= DINode::DIFlags::FlagIntroducedVirtual;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagBitField)) {
+    Result |= DINode::DIFlags::FlagBitField;
+  }
+  if (isSet(Flags & LLVMRustDIFlags::FlagNoReturn)) {
+    Result |= DINode::DIFlags::FlagNoReturn;
+  }
+
+  return Result;
+}
+
+// These values **must** match debuginfo::DISPFlags! They also *happen*
+// to match LLVM, but that isn't required as we do giant sets of
+// matching below. The value shouldn't be directly passed to LLVM.
+enum class LLVMRustDISPFlags : uint32_t {
+  SPFlagZero = 0,
+  SPFlagVirtual = 1,
+  SPFlagPureVirtual = 2,
+  SPFlagLocalToUnit = (1 << 2),
+  SPFlagDefinition = (1 << 3),
+  SPFlagOptimized = (1 << 4),
+  SPFlagMainSubprogram = (1 << 5),
+  // Do not add values that are not supported by the minimum LLVM
+  // version we support! see llvm/include/llvm/IR/DebugInfoFlags.def
+  // (In LLVM < 8, createFunction supported these as separate bool arguments.)
+};
+
+inline LLVMRustDISPFlags operator&(LLVMRustDISPFlags A, LLVMRustDISPFlags B) {
+  return static_cast<LLVMRustDISPFlags>(static_cast<uint32_t>(A) &
+                                      static_cast<uint32_t>(B));
+}
+
+inline LLVMRustDISPFlags operator|(LLVMRustDISPFlags A, LLVMRustDISPFlags B) {
+  return static_cast<LLVMRustDISPFlags>(static_cast<uint32_t>(A) |
+                                      static_cast<uint32_t>(B));
+}
+
+inline LLVMRustDISPFlags &operator|=(LLVMRustDISPFlags &A, LLVMRustDISPFlags B) {
+  return A = A | B;
+}
+
+inline bool isSet(LLVMRustDISPFlags F) { return F != LLVMRustDISPFlags::SPFlagZero; }
+
+inline LLVMRustDISPFlags virtuality(LLVMRustDISPFlags F) {
+  return static_cast<LLVMRustDISPFlags>(static_cast<uint32_t>(F) & 0x3);
+}
+
+static DISubprogram::DISPFlags fromRust(LLVMRustDISPFlags SPFlags) {
+  DISubprogram::DISPFlags Result = DISubprogram::DISPFlags::SPFlagZero;
+
+  switch (virtuality(SPFlags)) {
+  case LLVMRustDISPFlags::SPFlagVirtual:
+    Result |= DISubprogram::DISPFlags::SPFlagVirtual;
+    break;
+  case LLVMRustDISPFlags::SPFlagPureVirtual:
+    Result |= DISubprogram::DISPFlags::SPFlagPureVirtual;
+    break;
+  default:
+    // The rest are handled below
+    break;
+  }
+
+  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagLocalToUnit)) {
+    Result |= DISubprogram::DISPFlags::SPFlagLocalToUnit;
+  }
+  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagDefinition)) {
+    Result |= DISubprogram::DISPFlags::SPFlagDefinition;
+  }
+  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagOptimized)) {
+    Result |= DISubprogram::DISPFlags::SPFlagOptimized;
+  }
+#if LLVM_VERSION_GE(9, 0)
+  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagMainSubprogram)) {
+    Result |= DISubprogram::DISPFlags::SPFlagMainSubprogram;
+  }
+#endif
+
+  return Result;
+}
+
+enum class LLVMRustDebugEmissionKind {
+  NoDebug,
+  FullDebug,
+  LineTablesOnly,
+};
+
+static DICompileUnit::DebugEmissionKind fromRust(LLVMRustDebugEmissionKind Kind) {
+  switch (Kind) {
+  case LLVMRustDebugEmissionKind::NoDebug:
+    return DICompileUnit::DebugEmissionKind::NoDebug;
+  case LLVMRustDebugEmissionKind::FullDebug:
+    return DICompileUnit::DebugEmissionKind::FullDebug;
+  case LLVMRustDebugEmissionKind::LineTablesOnly:
+    return DICompileUnit::DebugEmissionKind::LineTablesOnly;
+  default:
+    report_fatal_error("bad DebugEmissionKind.");
+  }
+}
+
+enum class LLVMRustChecksumKind {
+  None,
+  MD5,
+  SHA1,
+};
+
+static Optional<DIFile::ChecksumKind> fromRust(LLVMRustChecksumKind Kind) {
+  switch (Kind) {
+  case LLVMRustChecksumKind::None:
+    return None;
+  case LLVMRustChecksumKind::MD5:
+    return DIFile::ChecksumKind::CSK_MD5;
+  case LLVMRustChecksumKind::SHA1:
+    return DIFile::ChecksumKind::CSK_SHA1;
+  default:
+    report_fatal_error("bad ChecksumKind.");
+  }
+}
+
+extern "C" uint32_t LLVMRustDebugMetadataVersion() {
+  return DEBUG_METADATA_VERSION;
+}
+
+extern "C" uint32_t LLVMRustVersionMinor() { return LLVM_VERSION_MINOR; }
+
+extern "C" uint32_t LLVMRustVersionMajor() { return LLVM_VERSION_MAJOR; }
+
+extern "C" void LLVMRustAddModuleFlag(LLVMModuleRef M, const char *Name,
+                                      uint32_t Value) {
+  unwrap(M)->addModuleFlag(Module::Warning, Name, Value);
+}
+
+extern "C" LLVMValueRef LLVMRustMetadataAsValue(LLVMContextRef C, LLVMMetadataRef MD) {
+  return wrap(MetadataAsValue::get(*unwrap(C), unwrap(MD)));
+}
+
+extern "C" LLVMRustDIBuilderRef LLVMRustDIBuilderCreate(LLVMModuleRef M) {
+  return new DIBuilder(*unwrap(M));
+}
+
+extern "C" void LLVMRustDIBuilderDispose(LLVMRustDIBuilderRef Builder) {
+  delete Builder;
+}
+
+extern "C" void LLVMRustDIBuilderFinalize(LLVMRustDIBuilderRef Builder) {
+  Builder->finalize();
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateCompileUnit(
+    LLVMRustDIBuilderRef Builder, unsigned Lang, LLVMMetadataRef FileRef,
+    const char *Producer, size_t ProducerLen, bool isOptimized,
+    const char *Flags, unsigned RuntimeVer,
+    const char *SplitName, size_t SplitNameLen,
+    LLVMRustDebugEmissionKind Kind) {
+  auto *File = unwrapDI<DIFile>(FileRef);
+
+  return wrap(Builder->createCompileUnit(Lang, File, StringRef(Producer, ProducerLen),
+                                         isOptimized, Flags, RuntimeVer,
+                                         StringRef(SplitName, SplitNameLen),
+                                         fromRust(Kind)));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateFile(
+    LLVMRustDIBuilderRef Builder,
+    const char *Filename, size_t FilenameLen,
+    const char *Directory, size_t DirectoryLen, LLVMRustChecksumKind CSKind,
+    const char *Checksum, size_t ChecksumLen) {
+  Optional<DIFile::ChecksumKind> llvmCSKind = fromRust(CSKind);
+  Optional<DIFile::ChecksumInfo<StringRef>> CSInfo{};
+  if (llvmCSKind)
+    CSInfo.emplace(*llvmCSKind, StringRef{Checksum, ChecksumLen});
+  return wrap(Builder->createFile(StringRef(Filename, FilenameLen),
+                                  StringRef(Directory, DirectoryLen),
+                                  CSInfo));
+}
+
+extern "C" LLVMMetadataRef
+LLVMRustDIBuilderCreateSubroutineType(LLVMRustDIBuilderRef Builder,
+                                      LLVMMetadataRef ParameterTypes) {
+  return wrap(Builder->createSubroutineType(
+      DITypeRefArray(unwrap<MDTuple>(ParameterTypes))));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateFunction(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
+    const char *Name, size_t NameLen,
+    const char *LinkageName, size_t LinkageNameLen,
+    LLVMMetadataRef File, unsigned LineNo,
+    LLVMMetadataRef Ty, unsigned ScopeLine, LLVMRustDIFlags Flags,
+    LLVMRustDISPFlags SPFlags, LLVMValueRef Fn, LLVMMetadataRef TParam,
+    LLVMMetadataRef Decl) {
+  DITemplateParameterArray TParams =
+      DITemplateParameterArray(unwrap<MDTuple>(TParam));
+  DISubprogram::DISPFlags llvmSPFlags = fromRust(SPFlags);
+  DINode::DIFlags llvmFlags = fromRust(Flags);
+#if LLVM_VERSION_LT(9, 0)
+  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagMainSubprogram))
+    llvmFlags |= DINode::DIFlags::FlagMainSubprogram;
+#endif
+  DISubprogram *Sub = Builder->createFunction(
+      unwrapDI<DIScope>(Scope),
+      StringRef(Name, NameLen),
+      StringRef(LinkageName, LinkageNameLen),
+      unwrapDI<DIFile>(File), LineNo,
+      unwrapDI<DISubroutineType>(Ty), ScopeLine, llvmFlags,
+      llvmSPFlags, TParams, unwrapDIPtr<DISubprogram>(Decl));
+  unwrap<Function>(Fn)->setSubprogram(Sub);
+  return wrap(Sub);
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateBasicType(
+    LLVMRustDIBuilderRef Builder, const char *Name, size_t NameLen,
+    uint64_t SizeInBits, unsigned Encoding) {
+  return wrap(Builder->createBasicType(StringRef(Name, NameLen), SizeInBits, Encoding));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateTypedef(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Type, const char *Name, size_t NameLen,
+    LLVMMetadataRef File, unsigned LineNo, LLVMMetadataRef Scope) {
+  return wrap(Builder->createTypedef(
+    unwrap<DIType>(Type), StringRef(Name, NameLen), unwrap<DIFile>(File),
+    LineNo, unwrap<DIScope>(Scope)));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreatePointerType(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef PointeeTy,
+    uint64_t SizeInBits, uint32_t AlignInBits, unsigned AddressSpace,
+    const char *Name, size_t NameLen) {
+  return wrap(Builder->createPointerType(unwrapDI<DIType>(PointeeTy),
+                                         SizeInBits, AlignInBits,
+                                         AddressSpace,
+                                         StringRef(Name, NameLen)));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateStructType(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
+    const char *Name, size_t NameLen,
+    LLVMMetadataRef File, unsigned LineNumber, uint64_t SizeInBits,
+    uint32_t AlignInBits, LLVMRustDIFlags Flags,
+    LLVMMetadataRef DerivedFrom, LLVMMetadataRef Elements,
+    unsigned RunTimeLang, LLVMMetadataRef VTableHolder,
+    const char *UniqueId, size_t UniqueIdLen) {
+  return wrap(Builder->createStructType(
+      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
+      unwrapDI<DIFile>(File), LineNumber,
+      SizeInBits, AlignInBits, fromRust(Flags), unwrapDI<DIType>(DerivedFrom),
+      DINodeArray(unwrapDI<MDTuple>(Elements)), RunTimeLang,
+      unwrapDI<DIType>(VTableHolder), StringRef(UniqueId, UniqueIdLen)));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateVariantPart(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
+    const char *Name, size_t NameLen,
+    LLVMMetadataRef File, unsigned LineNumber, uint64_t SizeInBits,
+    uint32_t AlignInBits, LLVMRustDIFlags Flags, LLVMMetadataRef Discriminator,
+    LLVMMetadataRef Elements, const char *UniqueId, size_t UniqueIdLen) {
+  return wrap(Builder->createVariantPart(
+      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
+      unwrapDI<DIFile>(File), LineNumber,
+      SizeInBits, AlignInBits, fromRust(Flags), unwrapDI<DIDerivedType>(Discriminator),
+      DINodeArray(unwrapDI<MDTuple>(Elements)), StringRef(UniqueId, UniqueIdLen)));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateMemberType(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
+    const char *Name, size_t NameLen,
+    LLVMMetadataRef File, unsigned LineNo, uint64_t SizeInBits,
+    uint32_t AlignInBits, uint64_t OffsetInBits, LLVMRustDIFlags Flags,
+    LLVMMetadataRef Ty) {
+  return wrap(Builder->createMemberType(unwrapDI<DIDescriptor>(Scope),
+                                        StringRef(Name, NameLen),
+                                        unwrapDI<DIFile>(File), LineNo,
+                                        SizeInBits, AlignInBits, OffsetInBits,
+                                        fromRust(Flags), unwrapDI<DIType>(Ty)));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateVariantMemberType(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
+    const char *Name, size_t NameLen, LLVMMetadataRef File, unsigned LineNo,
+    uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits, LLVMValueRef Discriminant,
+    LLVMRustDIFlags Flags, LLVMMetadataRef Ty) {
+  llvm::ConstantInt* D = nullptr;
+  if (Discriminant) {
+    D = unwrap<llvm::ConstantInt>(Discriminant);
+  }
+  return wrap(Builder->createVariantMemberType(unwrapDI<DIDescriptor>(Scope),
+                                               StringRef(Name, NameLen),
+                                               unwrapDI<DIFile>(File), LineNo,
+                                               SizeInBits, AlignInBits, OffsetInBits, D,
+                                               fromRust(Flags), unwrapDI<DIType>(Ty)));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateLexicalBlock(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
+    LLVMMetadataRef File, unsigned Line, unsigned Col) {
+  return wrap(Builder->createLexicalBlock(unwrapDI<DIDescriptor>(Scope),
+                                          unwrapDI<DIFile>(File), Line, Col));
+}
+
+extern "C" LLVMMetadataRef
+LLVMRustDIBuilderCreateLexicalBlockFile(LLVMRustDIBuilderRef Builder,
+                                        LLVMMetadataRef Scope,
+                                        LLVMMetadataRef File) {
+  return wrap(Builder->createLexicalBlockFile(unwrapDI<DIDescriptor>(Scope),
+                                              unwrapDI<DIFile>(File)));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateStaticVariable(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Context,
+    const char *Name, size_t NameLen,
+    const char *LinkageName, size_t LinkageNameLen,
+    LLVMMetadataRef File, unsigned LineNo,
+    LLVMMetadataRef Ty, bool IsLocalToUnit, LLVMValueRef V,
+    LLVMMetadataRef Decl = nullptr, uint32_t AlignInBits = 0) {
+  llvm::GlobalVariable *InitVal = cast<llvm::GlobalVariable>(unwrap(V));
+
+  llvm::DIExpression *InitExpr = nullptr;
+  if (llvm::ConstantInt *IntVal = llvm::dyn_cast<llvm::ConstantInt>(InitVal)) {
+    InitExpr = Builder->createConstantValueExpression(
+        IntVal->getValue().getSExtValue());
+  } else if (llvm::ConstantFP *FPVal =
+                 llvm::dyn_cast<llvm::ConstantFP>(InitVal)) {
+    InitExpr = Builder->createConstantValueExpression(
+        FPVal->getValueAPF().bitcastToAPInt().getZExtValue());
+  }
+
+  llvm::DIGlobalVariableExpression *VarExpr = Builder->createGlobalVariableExpression(
+      unwrapDI<DIDescriptor>(Context), StringRef(Name, NameLen),
+      StringRef(LinkageName, LinkageNameLen),
+      unwrapDI<DIFile>(File), LineNo, unwrapDI<DIType>(Ty), IsLocalToUnit,
+#if LLVM_VERSION_GE(10, 0)
+      /* isDefined */ true,
+#endif
+      InitExpr, unwrapDIPtr<MDNode>(Decl),
+      /* templateParams */ nullptr,
+      AlignInBits);
+
+  InitVal->setMetadata("dbg", VarExpr);
+
+  return wrap(VarExpr);
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateVariable(
+    LLVMRustDIBuilderRef Builder, unsigned Tag, LLVMMetadataRef Scope,
+    const char *Name, size_t NameLen,
+    LLVMMetadataRef File, unsigned LineNo,
+    LLVMMetadataRef Ty, bool AlwaysPreserve, LLVMRustDIFlags Flags,
+    unsigned ArgNo, uint32_t AlignInBits) {
+  if (Tag == 0x100) { // DW_TAG_auto_variable
+    return wrap(Builder->createAutoVariable(
+        unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
+        unwrapDI<DIFile>(File), LineNo,
+        unwrapDI<DIType>(Ty), AlwaysPreserve, fromRust(Flags), AlignInBits));
+  } else {
+    return wrap(Builder->createParameterVariable(
+        unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen), ArgNo,
+        unwrapDI<DIFile>(File), LineNo,
+        unwrapDI<DIType>(Ty), AlwaysPreserve, fromRust(Flags)));
+  }
+}
+
+extern "C" LLVMMetadataRef
+LLVMRustDIBuilderCreateArrayType(LLVMRustDIBuilderRef Builder, uint64_t Size,
+                                 uint32_t AlignInBits, LLVMMetadataRef Ty,
+                                 LLVMMetadataRef Subscripts) {
+  return wrap(
+      Builder->createArrayType(Size, AlignInBits, unwrapDI<DIType>(Ty),
+                               DINodeArray(unwrapDI<MDTuple>(Subscripts))));
+}
+
+extern "C" LLVMMetadataRef
+LLVMRustDIBuilderGetOrCreateSubrange(LLVMRustDIBuilderRef Builder, int64_t Lo,
+                                     int64_t Count) {
+  return wrap(Builder->getOrCreateSubrange(Lo, Count));
+}
+
+extern "C" LLVMMetadataRef
+LLVMRustDIBuilderGetOrCreateArray(LLVMRustDIBuilderRef Builder,
+                                  LLVMMetadataRef *Ptr, unsigned Count) {
+  Metadata **DataValue = unwrap(Ptr);
+  return wrap(
+      Builder->getOrCreateArray(ArrayRef<Metadata *>(DataValue, Count)).get());
+}
+
+extern "C" LLVMValueRef LLVMRustDIBuilderInsertDeclareAtEnd(
+    LLVMRustDIBuilderRef Builder, LLVMValueRef V, LLVMMetadataRef VarInfo,
+    int64_t *AddrOps, unsigned AddrOpsCount, LLVMValueRef DL,
+    LLVMBasicBlockRef InsertAtEnd) {
+  return wrap(Builder->insertDeclare(
+      unwrap(V), unwrap<DILocalVariable>(VarInfo),
+      Builder->createExpression(llvm::ArrayRef<int64_t>(AddrOps, AddrOpsCount)),
+      DebugLoc(cast<MDNode>(unwrap<MetadataAsValue>(DL)->getMetadata())),
+      unwrap(InsertAtEnd)));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateEnumerator(
+    LLVMRustDIBuilderRef Builder, const char *Name, size_t NameLen,
+    int64_t Value, bool IsUnsigned) {
+  return wrap(Builder->createEnumerator(StringRef(Name, NameLen), Value, IsUnsigned));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateEnumerationType(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
+    const char *Name, size_t NameLen,
+    LLVMMetadataRef File, unsigned LineNumber, uint64_t SizeInBits,
+    uint32_t AlignInBits, LLVMMetadataRef Elements,
+    LLVMMetadataRef ClassTy, bool IsScoped) {
+  return wrap(Builder->createEnumerationType(
+      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
+      unwrapDI<DIFile>(File), LineNumber,
+      SizeInBits, AlignInBits, DINodeArray(unwrapDI<MDTuple>(Elements)),
+      unwrapDI<DIType>(ClassTy), "", IsScoped));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateUnionType(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
+    const char *Name, size_t NameLen,
+    LLVMMetadataRef File, unsigned LineNumber, uint64_t SizeInBits,
+    uint32_t AlignInBits, LLVMRustDIFlags Flags, LLVMMetadataRef Elements,
+    unsigned RunTimeLang, const char *UniqueId, size_t UniqueIdLen) {
+  return wrap(Builder->createUnionType(
+      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen), unwrapDI<DIFile>(File),
+      LineNumber, SizeInBits, AlignInBits, fromRust(Flags),
+      DINodeArray(unwrapDI<MDTuple>(Elements)), RunTimeLang,
+      StringRef(UniqueId, UniqueIdLen)));
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateTemplateTypeParameter(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
+    const char *Name, size_t NameLen, LLVMMetadataRef Ty) {
+#if LLVM_VERSION_GE(11, 0)
+  bool IsDefault = false; // FIXME: should we ever set this true?
+  return wrap(Builder->createTemplateTypeParameter(
+      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen), unwrapDI<DIType>(Ty), IsDefault));
+#else
+  return wrap(Builder->createTemplateTypeParameter(
+      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen), unwrapDI<DIType>(Ty)));
+#endif
+}
+
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateNameSpace(
+    LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
+    const char *Name, size_t NameLen, bool ExportSymbols) {
+  return wrap(Builder->createNameSpace(
+      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen), ExportSymbols
+  ));
+}
+
+extern "C" void
+LLVMRustDICompositeTypeReplaceArrays(LLVMRustDIBuilderRef Builder,
+                                     LLVMMetadataRef CompositeTy,
+                                     LLVMMetadataRef Elements,
+                                     LLVMMetadataRef Params) {
+  DICompositeType *Tmp = unwrapDI<DICompositeType>(CompositeTy);
+  Builder->replaceArrays(Tmp, DINodeArray(unwrap<MDTuple>(Elements)),
+                         DINodeArray(unwrap<MDTuple>(Params)));
+}
+
+extern "C" LLVMValueRef
+LLVMRustDIBuilderCreateDebugLocation(LLVMContextRef ContextRef, unsigned Line,
+                                     unsigned Column, LLVMMetadataRef Scope,
+                                     LLVMMetadataRef InlinedAt) {
+  LLVMContext &Context = *unwrap(ContextRef);
+
+  DebugLoc debug_loc = DebugLoc::get(Line, Column, unwrapDIPtr<MDNode>(Scope),
+                                     unwrapDIPtr<MDNode>(InlinedAt));
+
+  return wrap(MetadataAsValue::get(Context, debug_loc.getAsMDNode()));
+}
+
+extern "C" int64_t LLVMRustDIBuilderCreateOpDeref() {
+  return dwarf::DW_OP_deref;
+}
+
+extern "C" int64_t LLVMRustDIBuilderCreateOpPlusUconst() {
+  return dwarf::DW_OP_plus_uconst;
+}
+
+extern "C" void LLVMRustWriteTypeToString(LLVMTypeRef Ty, RustStringRef Str) {
+  RawRustStringOstream OS(Str);
+  unwrap<llvm::Type>(Ty)->print(OS);
+}
+
+extern "C" void LLVMRustWriteValueToString(LLVMValueRef V,
+                                           RustStringRef Str) {
+  RawRustStringOstream OS(Str);
+  if (!V) {
+    OS << "(null)";
+  } else {
+    OS << "(";
+    unwrap<llvm::Value>(V)->getType()->print(OS);
+    OS << ":";
+    unwrap<llvm::Value>(V)->print(OS);
+    OS << ")";
+  }
+}
+
+// Note that the two following functions look quite similar to the
+// LLVMGetSectionName function. Sadly, it appears that this function only
+// returns a char* pointer, which isn't guaranteed to be null-terminated. The
+// function provided by LLVM doesn't return the length, so we've created our own
+// function which returns the length as well as the data pointer.
+//
+// For an example of this not returning a null terminated string, see
+// lib/Object/COFFObjectFile.cpp in the getSectionName function. One of the
+// branches explicitly creates a StringRef without a null terminator, and then
+// that's returned.
+
+inline section_iterator *unwrap(LLVMSectionIteratorRef SI) {
+  return reinterpret_cast<section_iterator *>(SI);
+}
+
+extern "C" size_t LLVMRustGetSectionName(LLVMSectionIteratorRef SI,
+                                         const char **Ptr) {
+#if LLVM_VERSION_GE(10, 0)
+  auto NameOrErr = (*unwrap(SI))->getName();
+  if (!NameOrErr)
+    report_fatal_error(NameOrErr.takeError());
+  *Ptr = NameOrErr->data();
+  return NameOrErr->size();
+#else
+  StringRef Ret;
+  if (std::error_code EC = (*unwrap(SI))->getName(Ret))
+    report_fatal_error(EC.message());
+  *Ptr = Ret.data();
+  return Ret.size();
+#endif
+}
+
+// LLVMArrayType function does not support 64-bit ElementCount
+extern "C" LLVMTypeRef LLVMRustArrayType(LLVMTypeRef ElementTy,
+                                         uint64_t ElementCount) {
+  return wrap(ArrayType::get(unwrap(ElementTy), ElementCount));
+}
+
+DEFINE_SIMPLE_CONVERSION_FUNCTIONS(Twine, LLVMTwineRef)
+
+extern "C" void LLVMRustWriteTwineToString(LLVMTwineRef T, RustStringRef Str) {
+  RawRustStringOstream OS(Str);
+  unwrap(T)->print(OS);
+}
+
+extern "C" void LLVMRustUnpackOptimizationDiagnostic(
+    LLVMDiagnosticInfoRef DI, RustStringRef PassNameOut,
+    LLVMValueRef *FunctionOut, unsigned* Line, unsigned* Column,
+    RustStringRef FilenameOut, RustStringRef MessageOut) {
+  // Undefined to call this not on an optimization diagnostic!
+  llvm::DiagnosticInfoOptimizationBase *Opt =
+      static_cast<llvm::DiagnosticInfoOptimizationBase *>(unwrap(DI));
+
+  RawRustStringOstream PassNameOS(PassNameOut);
+  PassNameOS << Opt->getPassName();
+  *FunctionOut = wrap(&Opt->getFunction());
+
+  RawRustStringOstream FilenameOS(FilenameOut);
+  DiagnosticLocation loc = Opt->getLocation();
+  if (loc.isValid()) {
+    *Line = loc.getLine();
+    *Column = loc.getColumn();
+    FilenameOS << loc.getAbsolutePath();
+  }
+
+  RawRustStringOstream MessageOS(MessageOut);
+  MessageOS << Opt->getMsg();
+}
+
+enum class LLVMRustDiagnosticLevel {
+    Error,
+    Warning,
+    Note,
+    Remark,
+};
+
+extern "C" void
+LLVMRustUnpackInlineAsmDiagnostic(LLVMDiagnosticInfoRef DI,
+                                  LLVMRustDiagnosticLevel *LevelOut,
+                                  unsigned *CookieOut,
+                                  LLVMTwineRef *MessageOut,
+                                  LLVMValueRef *InstructionOut) {
+  // Undefined to call this not on an inline assembly diagnostic!
+  llvm::DiagnosticInfoInlineAsm *IA =
+      static_cast<llvm::DiagnosticInfoInlineAsm *>(unwrap(DI));
+
+  *CookieOut = IA->getLocCookie();
+  *MessageOut = wrap(&IA->getMsgStr());
+  *InstructionOut = wrap(IA->getInstruction());
+
+  switch (IA->getSeverity()) {
+    case DS_Error:
+      *LevelOut = LLVMRustDiagnosticLevel::Error;
+      break;
+    case DS_Warning:
+      *LevelOut = LLVMRustDiagnosticLevel::Warning;
+      break;
+    case DS_Note:
+      *LevelOut = LLVMRustDiagnosticLevel::Note;
+      break;
+    case DS_Remark:
+      *LevelOut = LLVMRustDiagnosticLevel::Remark;
+      break;
+    default:
+      report_fatal_error("Invalid LLVMRustDiagnosticLevel value!");
+  }
+}
+
+extern "C" void LLVMRustWriteDiagnosticInfoToString(LLVMDiagnosticInfoRef DI,
+                                                    RustStringRef Str) {
+  RawRustStringOstream OS(Str);
+  DiagnosticPrinterRawOStream DP(OS);
+  unwrap(DI)->print(DP);
+}
+
+enum class LLVMRustDiagnosticKind {
+  Other,
+  InlineAsm,
+  StackSize,
+  DebugMetadataVersion,
+  SampleProfile,
+  OptimizationRemark,
+  OptimizationRemarkMissed,
+  OptimizationRemarkAnalysis,
+  OptimizationRemarkAnalysisFPCommute,
+  OptimizationRemarkAnalysisAliasing,
+  OptimizationRemarkOther,
+  OptimizationFailure,
+  PGOProfile,
+  Linker,
+};
+
+static LLVMRustDiagnosticKind toRust(DiagnosticKind Kind) {
+  switch (Kind) {
+  case DK_InlineAsm:
+    return LLVMRustDiagnosticKind::InlineAsm;
+  case DK_StackSize:
+    return LLVMRustDiagnosticKind::StackSize;
+  case DK_DebugMetadataVersion:
+    return LLVMRustDiagnosticKind::DebugMetadataVersion;
+  case DK_SampleProfile:
+    return LLVMRustDiagnosticKind::SampleProfile;
+  case DK_OptimizationRemark:
+    return LLVMRustDiagnosticKind::OptimizationRemark;
+  case DK_OptimizationRemarkMissed:
+    return LLVMRustDiagnosticKind::OptimizationRemarkMissed;
+  case DK_OptimizationRemarkAnalysis:
+    return LLVMRustDiagnosticKind::OptimizationRemarkAnalysis;
+  case DK_OptimizationRemarkAnalysisFPCommute:
+    return LLVMRustDiagnosticKind::OptimizationRemarkAnalysisFPCommute;
+  case DK_OptimizationRemarkAnalysisAliasing:
+    return LLVMRustDiagnosticKind::OptimizationRemarkAnalysisAliasing;
+  case DK_PGOProfile:
+    return LLVMRustDiagnosticKind::PGOProfile;
+  case DK_Linker:
+    return LLVMRustDiagnosticKind::Linker;
+  default:
+    return (Kind >= DK_FirstRemark && Kind <= DK_LastRemark)
+               ? LLVMRustDiagnosticKind::OptimizationRemarkOther
+               : LLVMRustDiagnosticKind::Other;
+  }
+}
+
+extern "C" LLVMRustDiagnosticKind
+LLVMRustGetDiagInfoKind(LLVMDiagnosticInfoRef DI) {
+  return toRust((DiagnosticKind)unwrap(DI)->getKind());
+}
+
+// This is kept distinct from LLVMGetTypeKind, because when
+// a new type kind is added, the Rust-side enum must be
+// updated or UB will result.
+extern "C" LLVMTypeKind LLVMRustGetTypeKind(LLVMTypeRef Ty) {
+  switch (unwrap(Ty)->getTypeID()) {
+  case Type::VoidTyID:
+    return LLVMVoidTypeKind;
+  case Type::HalfTyID:
+    return LLVMHalfTypeKind;
+  case Type::FloatTyID:
+    return LLVMFloatTypeKind;
+  case Type::DoubleTyID:
+    return LLVMDoubleTypeKind;
+  case Type::X86_FP80TyID:
+    return LLVMX86_FP80TypeKind;
+  case Type::FP128TyID:
+    return LLVMFP128TypeKind;
+  case Type::PPC_FP128TyID:
+    return LLVMPPC_FP128TypeKind;
+  case Type::LabelTyID:
+    return LLVMLabelTypeKind;
+  case Type::MetadataTyID:
+    return LLVMMetadataTypeKind;
+  case Type::IntegerTyID:
+    return LLVMIntegerTypeKind;
+  case Type::FunctionTyID:
+    return LLVMFunctionTypeKind;
+  case Type::StructTyID:
+    return LLVMStructTypeKind;
+  case Type::ArrayTyID:
+    return LLVMArrayTypeKind;
+  case Type::PointerTyID:
+    return LLVMPointerTypeKind;
+#if LLVM_VERSION_GE(11, 0)
+  case Type::FixedVectorTyID:
+    return LLVMVectorTypeKind;
+#else
+  case Type::VectorTyID:
+    return LLVMVectorTypeKind;
+#endif
+  case Type::X86_MMXTyID:
+    return LLVMX86_MMXTypeKind;
+  case Type::TokenTyID:
+    return LLVMTokenTypeKind;
+#if LLVM_VERSION_GE(11, 0)
+  case Type::ScalableVectorTyID:
+    return LLVMScalableVectorTypeKind;
+  case Type::BFloatTyID:
+    return LLVMBFloatTypeKind;
+#endif
+  }
+  report_fatal_error("Unhandled TypeID.");
+}
+
+DEFINE_SIMPLE_CONVERSION_FUNCTIONS(SMDiagnostic, LLVMSMDiagnosticRef)
+
+extern "C" void LLVMRustSetInlineAsmDiagnosticHandler(
+    LLVMContextRef C, LLVMContext::InlineAsmDiagHandlerTy H, void *CX) {
+  unwrap(C)->setInlineAsmDiagnosticHandler(H, CX);
+}
+
+extern "C" bool LLVMRustUnpackSMDiagnostic(LLVMSMDiagnosticRef DRef,
+                                           RustStringRef MessageOut,
+                                           RustStringRef BufferOut,
+                                           LLVMRustDiagnosticLevel* LevelOut,
+                                           unsigned* LocOut,
+                                           unsigned* RangesOut,
+                                           size_t* NumRanges) {
+  SMDiagnostic& D = *unwrap(DRef);
+  RawRustStringOstream MessageOS(MessageOut);
+  MessageOS << D.getMessage();
+
+  switch (D.getKind()) {
+    case SourceMgr::DK_Error:
+      *LevelOut = LLVMRustDiagnosticLevel::Error;
+      break;
+    case SourceMgr::DK_Warning:
+      *LevelOut = LLVMRustDiagnosticLevel::Warning;
+      break;
+    case SourceMgr::DK_Note:
+      *LevelOut = LLVMRustDiagnosticLevel::Note;
+      break;
+    case SourceMgr::DK_Remark:
+      *LevelOut = LLVMRustDiagnosticLevel::Remark;
+      break;
+    default:
+      report_fatal_error("Invalid LLVMRustDiagnosticLevel value!");
+  }
+
+  if (D.getLoc() == SMLoc())
+    return false;
+
+  const SourceMgr &LSM = *D.getSourceMgr();
+  const MemoryBuffer *LBuf = LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
+  LLVMRustStringWriteImpl(BufferOut, LBuf->getBufferStart(), LBuf->getBufferSize());
+
+  *LocOut = D.getLoc().getPointer() - LBuf->getBufferStart();
+
+  *NumRanges = std::min(*NumRanges, D.getRanges().size());
+  size_t LineStart = *LocOut - (size_t)D.getColumnNo();
+  for (size_t i = 0; i < *NumRanges; i++) {
+    RangesOut[i * 2] = LineStart + D.getRanges()[i].first;
+    RangesOut[i * 2 + 1] = LineStart + D.getRanges()[i].second;
+  }
+
+  return true;
+}
+
+extern "C" LLVMValueRef LLVMRustBuildCleanupPad(LLVMBuilderRef B,
+                                                LLVMValueRef ParentPad,
+                                                unsigned ArgCount,
+                                                LLVMValueRef *LLArgs,
+                                                const char *Name) {
+  Value **Args = unwrap(LLArgs);
+  if (ParentPad == nullptr) {
+    Type *Ty = Type::getTokenTy(unwrap(B)->getContext());
+    ParentPad = wrap(Constant::getNullValue(Ty));
+  }
+  return wrap(unwrap(B)->CreateCleanupPad(
+      unwrap(ParentPad), ArrayRef<Value *>(Args, ArgCount), Name));
+}
+
+extern "C" LLVMValueRef LLVMRustBuildCleanupRet(LLVMBuilderRef B,
+                                                LLVMValueRef CleanupPad,
+                                                LLVMBasicBlockRef UnwindBB) {
+  CleanupPadInst *Inst = cast<CleanupPadInst>(unwrap(CleanupPad));
+  return wrap(unwrap(B)->CreateCleanupRet(Inst, unwrap(UnwindBB)));
+}
+
+extern "C" LLVMValueRef
+LLVMRustBuildCatchPad(LLVMBuilderRef B, LLVMValueRef ParentPad,
+                      unsigned ArgCount, LLVMValueRef *LLArgs, const char *Name) {
+  Value **Args = unwrap(LLArgs);
+  return wrap(unwrap(B)->CreateCatchPad(
+      unwrap(ParentPad), ArrayRef<Value *>(Args, ArgCount), Name));
+}
+
+extern "C" LLVMValueRef LLVMRustBuildCatchRet(LLVMBuilderRef B,
+                                              LLVMValueRef Pad,
+                                              LLVMBasicBlockRef BB) {
+  return wrap(unwrap(B)->CreateCatchRet(cast<CatchPadInst>(unwrap(Pad)),
+                                              unwrap(BB)));
+}
+
+extern "C" LLVMValueRef LLVMRustBuildCatchSwitch(LLVMBuilderRef B,
+                                                 LLVMValueRef ParentPad,
+                                                 LLVMBasicBlockRef BB,
+                                                 unsigned NumHandlers,
+                                                 const char *Name) {
+  if (ParentPad == nullptr) {
+    Type *Ty = Type::getTokenTy(unwrap(B)->getContext());
+    ParentPad = wrap(Constant::getNullValue(Ty));
+  }
+  return wrap(unwrap(B)->CreateCatchSwitch(unwrap(ParentPad), unwrap(BB),
+                                                 NumHandlers, Name));
+}
+
+extern "C" void LLVMRustAddHandler(LLVMValueRef CatchSwitchRef,
+                                   LLVMBasicBlockRef Handler) {
+  Value *CatchSwitch = unwrap(CatchSwitchRef);
+  cast<CatchSwitchInst>(CatchSwitch)->addHandler(unwrap(Handler));
+}
+
+extern "C" OperandBundleDef *LLVMRustBuildOperandBundleDef(const char *Name,
+                                                           LLVMValueRef *Inputs,
+                                                           unsigned NumInputs) {
+  return new OperandBundleDef(Name, makeArrayRef(unwrap(Inputs), NumInputs));
+}
+
+extern "C" void LLVMRustFreeOperandBundleDef(OperandBundleDef *Bundle) {
+  delete Bundle;
+}
+
+extern "C" LLVMValueRef LLVMRustBuildCall(LLVMBuilderRef B, LLVMValueRef Fn,
+                                          LLVMValueRef *Args, unsigned NumArgs,
+                                          OperandBundleDef *Bundle) {
+  Value *Callee = unwrap(Fn);
+  FunctionType *FTy = cast<FunctionType>(Callee->getType()->getPointerElementType());
+  unsigned Len = Bundle ? 1 : 0;
+  ArrayRef<OperandBundleDef> Bundles = makeArrayRef(Bundle, Len);
+  return wrap(unwrap(B)->CreateCall(
+      FTy, Callee, makeArrayRef(unwrap(Args), NumArgs), Bundles));
+}
+
+extern "C" LLVMValueRef LLVMRustGetInstrProfIncrementIntrinsic(LLVMModuleRef M) {
+  return wrap(llvm::Intrinsic::getDeclaration(unwrap(M),
+              (llvm::Intrinsic::ID)llvm::Intrinsic::instrprof_increment));
+}
+
+extern "C" LLVMValueRef LLVMRustBuildMemCpy(LLVMBuilderRef B,
+                                            LLVMValueRef Dst, unsigned DstAlign,
+                                            LLVMValueRef Src, unsigned SrcAlign,
+                                            LLVMValueRef Size, bool IsVolatile) {
+#if LLVM_VERSION_GE(10, 0)
+  return wrap(unwrap(B)->CreateMemCpy(
+      unwrap(Dst), MaybeAlign(DstAlign),
+      unwrap(Src), MaybeAlign(SrcAlign),
+      unwrap(Size), IsVolatile));
+#else
+  return wrap(unwrap(B)->CreateMemCpy(
+      unwrap(Dst), DstAlign,
+      unwrap(Src), SrcAlign,
+      unwrap(Size), IsVolatile));
+#endif
+}
+
+extern "C" LLVMValueRef LLVMRustBuildMemMove(LLVMBuilderRef B,
+                                             LLVMValueRef Dst, unsigned DstAlign,
+                                             LLVMValueRef Src, unsigned SrcAlign,
+                                             LLVMValueRef Size, bool IsVolatile) {
+#if LLVM_VERSION_GE(10, 0)
+  return wrap(unwrap(B)->CreateMemMove(
+      unwrap(Dst), MaybeAlign(DstAlign),
+      unwrap(Src), MaybeAlign(SrcAlign),
+      unwrap(Size), IsVolatile));
+#else
+  return wrap(unwrap(B)->CreateMemMove(
+      unwrap(Dst), DstAlign,
+      unwrap(Src), SrcAlign,
+      unwrap(Size), IsVolatile));
+#endif
+}
+
+extern "C" LLVMValueRef LLVMRustBuildMemSet(LLVMBuilderRef B,
+                                            LLVMValueRef Dst, unsigned DstAlign,
+                                            LLVMValueRef Val,
+                                            LLVMValueRef Size, bool IsVolatile) {
+#if LLVM_VERSION_GE(10, 0)
+  return wrap(unwrap(B)->CreateMemSet(
+      unwrap(Dst), unwrap(Val), unwrap(Size), MaybeAlign(DstAlign), IsVolatile));
+#else
+  return wrap(unwrap(B)->CreateMemSet(
+      unwrap(Dst), unwrap(Val), unwrap(Size), DstAlign, IsVolatile));
+#endif
+}
+
+extern "C" LLVMValueRef
+LLVMRustBuildInvoke(LLVMBuilderRef B, LLVMValueRef Fn, LLVMValueRef *Args,
+                    unsigned NumArgs, LLVMBasicBlockRef Then,
+                    LLVMBasicBlockRef Catch, OperandBundleDef *Bundle,
+                    const char *Name) {
+  Value *Callee = unwrap(Fn);
+  FunctionType *FTy = cast<FunctionType>(Callee->getType()->getPointerElementType());
+  unsigned Len = Bundle ? 1 : 0;
+  ArrayRef<OperandBundleDef> Bundles = makeArrayRef(Bundle, Len);
+  return wrap(unwrap(B)->CreateInvoke(FTy, Callee, unwrap(Then), unwrap(Catch),
+                                      makeArrayRef(unwrap(Args), NumArgs),
+                                      Bundles, Name));
+}
+
+extern "C" void LLVMRustPositionBuilderAtStart(LLVMBuilderRef B,
+                                               LLVMBasicBlockRef BB) {
+  auto Point = unwrap(BB)->getFirstInsertionPt();
+  unwrap(B)->SetInsertPoint(unwrap(BB), Point);
+}
+
+extern "C" void LLVMRustSetComdat(LLVMModuleRef M, LLVMValueRef V,
+                                  const char *Name, size_t NameLen) {
+  Triple TargetTriple(unwrap(M)->getTargetTriple());
+  GlobalObject *GV = unwrap<GlobalObject>(V);
+  if (!TargetTriple.isOSBinFormatMachO()) {
+    StringRef NameRef(Name, NameLen);
+    GV->setComdat(unwrap(M)->getOrInsertComdat(NameRef));
+  }
+}
+
+extern "C" void LLVMRustUnsetComdat(LLVMValueRef V) {
+  GlobalObject *GV = unwrap<GlobalObject>(V);
+  GV->setComdat(nullptr);
+}
+
+enum class LLVMRustLinkage {
+  ExternalLinkage = 0,
+  AvailableExternallyLinkage = 1,
+  LinkOnceAnyLinkage = 2,
+  LinkOnceODRLinkage = 3,
+  WeakAnyLinkage = 4,
+  WeakODRLinkage = 5,
+  AppendingLinkage = 6,
+  InternalLinkage = 7,
+  PrivateLinkage = 8,
+  ExternalWeakLinkage = 9,
+  CommonLinkage = 10,
+};
+
+static LLVMRustLinkage toRust(LLVMLinkage Linkage) {
+  switch (Linkage) {
+  case LLVMExternalLinkage:
+    return LLVMRustLinkage::ExternalLinkage;
+  case LLVMAvailableExternallyLinkage:
+    return LLVMRustLinkage::AvailableExternallyLinkage;
+  case LLVMLinkOnceAnyLinkage:
+    return LLVMRustLinkage::LinkOnceAnyLinkage;
+  case LLVMLinkOnceODRLinkage:
+    return LLVMRustLinkage::LinkOnceODRLinkage;
+  case LLVMWeakAnyLinkage:
+    return LLVMRustLinkage::WeakAnyLinkage;
+  case LLVMWeakODRLinkage:
+    return LLVMRustLinkage::WeakODRLinkage;
+  case LLVMAppendingLinkage:
+    return LLVMRustLinkage::AppendingLinkage;
+  case LLVMInternalLinkage:
+    return LLVMRustLinkage::InternalLinkage;
+  case LLVMPrivateLinkage:
+    return LLVMRustLinkage::PrivateLinkage;
+  case LLVMExternalWeakLinkage:
+    return LLVMRustLinkage::ExternalWeakLinkage;
+  case LLVMCommonLinkage:
+    return LLVMRustLinkage::CommonLinkage;
+  default:
+    report_fatal_error("Invalid LLVMRustLinkage value!");
+  }
+}
+
+static LLVMLinkage fromRust(LLVMRustLinkage Linkage) {
+  switch (Linkage) {
+  case LLVMRustLinkage::ExternalLinkage:
+    return LLVMExternalLinkage;
+  case LLVMRustLinkage::AvailableExternallyLinkage:
+    return LLVMAvailableExternallyLinkage;
+  case LLVMRustLinkage::LinkOnceAnyLinkage:
+    return LLVMLinkOnceAnyLinkage;
+  case LLVMRustLinkage::LinkOnceODRLinkage:
+    return LLVMLinkOnceODRLinkage;
+  case LLVMRustLinkage::WeakAnyLinkage:
+    return LLVMWeakAnyLinkage;
+  case LLVMRustLinkage::WeakODRLinkage:
+    return LLVMWeakODRLinkage;
+  case LLVMRustLinkage::AppendingLinkage:
+    return LLVMAppendingLinkage;
+  case LLVMRustLinkage::InternalLinkage:
+    return LLVMInternalLinkage;
+  case LLVMRustLinkage::PrivateLinkage:
+    return LLVMPrivateLinkage;
+  case LLVMRustLinkage::ExternalWeakLinkage:
+    return LLVMExternalWeakLinkage;
+  case LLVMRustLinkage::CommonLinkage:
+    return LLVMCommonLinkage;
+  }
+  report_fatal_error("Invalid LLVMRustLinkage value!");
+}
+
+extern "C" LLVMRustLinkage LLVMRustGetLinkage(LLVMValueRef V) {
+  return toRust(LLVMGetLinkage(V));
+}
+
+extern "C" void LLVMRustSetLinkage(LLVMValueRef V,
+                                   LLVMRustLinkage RustLinkage) {
+  LLVMSetLinkage(V, fromRust(RustLinkage));
+}
+
+// Returns true if both high and low were successfully set. Fails in case constant wasn’t any of
+// the common sizes (1, 8, 16, 32, 64, 128 bits)
+extern "C" bool LLVMRustConstInt128Get(LLVMValueRef CV, bool sext, uint64_t *high, uint64_t *low)
+{
+    auto C = unwrap<llvm::ConstantInt>(CV);
+    if (C->getBitWidth() > 128) { return false; }
+    APInt AP;
+    if (sext) {
+        AP = C->getValue().sextOrSelf(128);
+    } else {
+        AP = C->getValue().zextOrSelf(128);
+    }
+    *low = AP.getLoBits(64).getZExtValue();
+    *high = AP.getHiBits(64).getZExtValue();
+    return true;
+}
+
+enum class LLVMRustVisibility {
+  Default = 0,
+  Hidden = 1,
+  Protected = 2,
+};
+
+static LLVMRustVisibility toRust(LLVMVisibility Vis) {
+  switch (Vis) {
+  case LLVMDefaultVisibility:
+    return LLVMRustVisibility::Default;
+  case LLVMHiddenVisibility:
+    return LLVMRustVisibility::Hidden;
+  case LLVMProtectedVisibility:
+    return LLVMRustVisibility::Protected;
+  }
+  report_fatal_error("Invalid LLVMRustVisibility value!");
+}
+
+static LLVMVisibility fromRust(LLVMRustVisibility Vis) {
+  switch (Vis) {
+  case LLVMRustVisibility::Default:
+    return LLVMDefaultVisibility;
+  case LLVMRustVisibility::Hidden:
+    return LLVMHiddenVisibility;
+  case LLVMRustVisibility::Protected:
+    return LLVMProtectedVisibility;
+  }
+  report_fatal_error("Invalid LLVMRustVisibility value!");
+}
+
+extern "C" LLVMRustVisibility LLVMRustGetVisibility(LLVMValueRef V) {
+  return toRust(LLVMGetVisibility(V));
+}
+
+// Oh hey, a binding that makes sense for once? (because LLVM’s own do not)
+extern "C" LLVMValueRef LLVMRustBuildIntCast(LLVMBuilderRef B, LLVMValueRef Val,
+                                             LLVMTypeRef DestTy, bool isSigned) {
+  return wrap(unwrap(B)->CreateIntCast(unwrap(Val), unwrap(DestTy), isSigned, ""));
+}
+
+extern "C" void LLVMRustSetVisibility(LLVMValueRef V,
+                                      LLVMRustVisibility RustVisibility) {
+  LLVMSetVisibility(V, fromRust(RustVisibility));
+}
+
+struct LLVMRustModuleBuffer {
+  std::string data;
+};
+
+extern "C" LLVMRustModuleBuffer*
+LLVMRustModuleBufferCreate(LLVMModuleRef M) {
+#if LLVM_VERSION_GE(10, 0)
+  auto Ret = std::make_unique<LLVMRustModuleBuffer>();
+#else
+  auto Ret = llvm::make_unique<LLVMRustModuleBuffer>();
+#endif
+  {
+    raw_string_ostream OS(Ret->data);
+    {
+      legacy::PassManager PM;
+      PM.add(createBitcodeWriterPass(OS));
+      PM.run(*unwrap(M));
+    }
+  }
+  return Ret.release();
+}
+
+extern "C" void
+LLVMRustModuleBufferFree(LLVMRustModuleBuffer *Buffer) {
+  delete Buffer;
+}
+
+extern "C" const void*
+LLVMRustModuleBufferPtr(const LLVMRustModuleBuffer *Buffer) {
+  return Buffer->data.data();
+}
+
+extern "C" size_t
+LLVMRustModuleBufferLen(const LLVMRustModuleBuffer *Buffer) {
+  return Buffer->data.length();
+}
+
+extern "C" uint64_t
+LLVMRustModuleCost(LLVMModuleRef M) {
+  auto f = unwrap(M)->functions();
+  return std::distance(std::begin(f), std::end(f));
+}
+
+// Vector reductions:
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceFAdd(LLVMBuilderRef B, LLVMValueRef Acc, LLVMValueRef Src) {
+    return wrap(unwrap(B)->CreateFAddReduce(unwrap(Acc),unwrap(Src)));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceFMul(LLVMBuilderRef B, LLVMValueRef Acc, LLVMValueRef Src) {
+    return wrap(unwrap(B)->CreateFMulReduce(unwrap(Acc),unwrap(Src)));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceAdd(LLVMBuilderRef B, LLVMValueRef Src) {
+    return wrap(unwrap(B)->CreateAddReduce(unwrap(Src)));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceMul(LLVMBuilderRef B, LLVMValueRef Src) {
+    return wrap(unwrap(B)->CreateMulReduce(unwrap(Src)));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceAnd(LLVMBuilderRef B, LLVMValueRef Src) {
+    return wrap(unwrap(B)->CreateAndReduce(unwrap(Src)));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceOr(LLVMBuilderRef B, LLVMValueRef Src) {
+    return wrap(unwrap(B)->CreateOrReduce(unwrap(Src)));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceXor(LLVMBuilderRef B, LLVMValueRef Src) {
+    return wrap(unwrap(B)->CreateXorReduce(unwrap(Src)));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceMin(LLVMBuilderRef B, LLVMValueRef Src, bool IsSigned) {
+    return wrap(unwrap(B)->CreateIntMinReduce(unwrap(Src), IsSigned));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceMax(LLVMBuilderRef B, LLVMValueRef Src, bool IsSigned) {
+    return wrap(unwrap(B)->CreateIntMaxReduce(unwrap(Src), IsSigned));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceFMin(LLVMBuilderRef B, LLVMValueRef Src, bool NoNaN) {
+   return wrap(unwrap(B)->CreateFPMinReduce(unwrap(Src), NoNaN));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildVectorReduceFMax(LLVMBuilderRef B, LLVMValueRef Src, bool NoNaN) {
+  return wrap(unwrap(B)->CreateFPMaxReduce(unwrap(Src), NoNaN));
+}
+
+extern "C" LLVMValueRef
+LLVMRustBuildMinNum(LLVMBuilderRef B, LLVMValueRef LHS, LLVMValueRef RHS) {
+    return wrap(unwrap(B)->CreateMinNum(unwrap(LHS),unwrap(RHS)));
+}
+extern "C" LLVMValueRef
+LLVMRustBuildMaxNum(LLVMBuilderRef B, LLVMValueRef LHS, LLVMValueRef RHS) {
+    return wrap(unwrap(B)->CreateMaxNum(unwrap(LHS),unwrap(RHS)));
+}
diff --git a/compiler/rustc_llvm/src/lib.rs b/compiler/rustc_llvm/src/lib.rs
new file mode 100644
index 00000000000..9d23397ade0
--- /dev/null
+++ b/compiler/rustc_llvm/src/lib.rs
@@ -0,0 +1,173 @@
+#![feature(nll)]
+#![feature(static_nobundle)]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+
+// NOTE: This crate only exists to allow linking on mingw targets.
+
+use libc::{c_char, size_t};
+use std::cell::RefCell;
+use std::slice;
+
+#[repr(C)]
+pub struct RustString {
+    pub bytes: RefCell<Vec<u8>>,
+}
+
+impl RustString {
+    pub fn len(&self) -> usize {
+        self.bytes.borrow().len()
+    }
+}
+
+/// Appending to a Rust string -- used by RawRustStringOstream.
+#[no_mangle]
+#[allow(improper_ctypes_definitions)]
+pub unsafe extern "C" fn LLVMRustStringWriteImpl(
+    sr: &RustString,
+    ptr: *const c_char,
+    size: size_t,
+) {
+    let slice = slice::from_raw_parts(ptr as *const u8, size as usize);
+
+    sr.bytes.borrow_mut().extend_from_slice(slice);
+}
+
+/// Initialize targets enabled by the build script via `cfg(llvm_component = "...")`.
+/// N.B., this function can't be moved to `rustc_codegen_llvm` because of the `cfg`s.
+pub fn initialize_available_targets() {
+    macro_rules! init_target(
+        ($cfg:meta, $($method:ident),*) => { {
+            #[cfg($cfg)]
+            fn init() {
+                extern {
+                    $(fn $method();)*
+                }
+                unsafe {
+                    $($method();)*
+                }
+            }
+            #[cfg(not($cfg))]
+            fn init() { }
+            init();
+        } }
+    );
+    init_target!(
+        llvm_component = "x86",
+        LLVMInitializeX86TargetInfo,
+        LLVMInitializeX86Target,
+        LLVMInitializeX86TargetMC,
+        LLVMInitializeX86AsmPrinter,
+        LLVMInitializeX86AsmParser
+    );
+    init_target!(
+        llvm_component = "arm",
+        LLVMInitializeARMTargetInfo,
+        LLVMInitializeARMTarget,
+        LLVMInitializeARMTargetMC,
+        LLVMInitializeARMAsmPrinter,
+        LLVMInitializeARMAsmParser
+    );
+    init_target!(
+        llvm_component = "aarch64",
+        LLVMInitializeAArch64TargetInfo,
+        LLVMInitializeAArch64Target,
+        LLVMInitializeAArch64TargetMC,
+        LLVMInitializeAArch64AsmPrinter,
+        LLVMInitializeAArch64AsmParser
+    );
+    init_target!(
+        llvm_component = "amdgpu",
+        LLVMInitializeAMDGPUTargetInfo,
+        LLVMInitializeAMDGPUTarget,
+        LLVMInitializeAMDGPUTargetMC,
+        LLVMInitializeAMDGPUAsmPrinter,
+        LLVMInitializeAMDGPUAsmParser
+    );
+    init_target!(
+        llvm_component = "avr",
+        LLVMInitializeAVRTargetInfo,
+        LLVMInitializeAVRTarget,
+        LLVMInitializeAVRTargetMC,
+        LLVMInitializeAVRAsmPrinter,
+        LLVMInitializeAVRAsmParser
+    );
+    init_target!(
+        llvm_component = "mips",
+        LLVMInitializeMipsTargetInfo,
+        LLVMInitializeMipsTarget,
+        LLVMInitializeMipsTargetMC,
+        LLVMInitializeMipsAsmPrinter,
+        LLVMInitializeMipsAsmParser
+    );
+    init_target!(
+        llvm_component = "powerpc",
+        LLVMInitializePowerPCTargetInfo,
+        LLVMInitializePowerPCTarget,
+        LLVMInitializePowerPCTargetMC,
+        LLVMInitializePowerPCAsmPrinter,
+        LLVMInitializePowerPCAsmParser
+    );
+    init_target!(
+        llvm_component = "systemz",
+        LLVMInitializeSystemZTargetInfo,
+        LLVMInitializeSystemZTarget,
+        LLVMInitializeSystemZTargetMC,
+        LLVMInitializeSystemZAsmPrinter,
+        LLVMInitializeSystemZAsmParser
+    );
+    init_target!(
+        llvm_component = "jsbackend",
+        LLVMInitializeJSBackendTargetInfo,
+        LLVMInitializeJSBackendTarget,
+        LLVMInitializeJSBackendTargetMC
+    );
+    init_target!(
+        llvm_component = "msp430",
+        LLVMInitializeMSP430TargetInfo,
+        LLVMInitializeMSP430Target,
+        LLVMInitializeMSP430TargetMC,
+        LLVMInitializeMSP430AsmPrinter
+    );
+    init_target!(
+        all(llvm_component = "msp430", llvm_has_msp430_asm_parser),
+        LLVMInitializeMSP430AsmParser
+    );
+    init_target!(
+        llvm_component = "riscv",
+        LLVMInitializeRISCVTargetInfo,
+        LLVMInitializeRISCVTarget,
+        LLVMInitializeRISCVTargetMC,
+        LLVMInitializeRISCVAsmPrinter,
+        LLVMInitializeRISCVAsmParser
+    );
+    init_target!(
+        llvm_component = "sparc",
+        LLVMInitializeSparcTargetInfo,
+        LLVMInitializeSparcTarget,
+        LLVMInitializeSparcTargetMC,
+        LLVMInitializeSparcAsmPrinter,
+        LLVMInitializeSparcAsmParser
+    );
+    init_target!(
+        llvm_component = "nvptx",
+        LLVMInitializeNVPTXTargetInfo,
+        LLVMInitializeNVPTXTarget,
+        LLVMInitializeNVPTXTargetMC,
+        LLVMInitializeNVPTXAsmPrinter
+    );
+    init_target!(
+        llvm_component = "hexagon",
+        LLVMInitializeHexagonTargetInfo,
+        LLVMInitializeHexagonTarget,
+        LLVMInitializeHexagonTargetMC,
+        LLVMInitializeHexagonAsmPrinter,
+        LLVMInitializeHexagonAsmParser
+    );
+    init_target!(
+        llvm_component = "webassembly",
+        LLVMInitializeWebAssemblyTargetInfo,
+        LLVMInitializeWebAssemblyTarget,
+        LLVMInitializeWebAssemblyTargetMC,
+        LLVMInitializeWebAssemblyAsmPrinter
+    );
+}