Revert "Rollup merge of #56944 - alexcrichton:less-thin2, r=michaelwoerister"

This reverts commit f1051b574c26e20608ff26415a3dddd13f140925, reversing
changes made to 833e0b3b8a9f1487a61152ca76f7f74a6b32cc0c.

11 files changed, 240 insertions, 18 deletions

diff --git a/src/bootstrap/check.rs b/src/bootstrap/check.rs
index 5d486c04b42..84e7c40e455 100644
--- a/src/bootstrap/check.rs
+++ b/src/bootstrap/check.rs
@@ -48,6 +48,7 @@ impl Step for Std {
         builder.info(&format!("Checking std artifacts ({} -> {})", &compiler.host, target));
         run_cargo(builder,
                   &mut cargo,
+                  vec![],
                   &libstd_stamp(builder, compiler, target),
                   true);
 
@@ -94,6 +95,7 @@ impl Step for Rustc {
         builder.info(&format!("Checking compiler artifacts ({} -> {})", &compiler.host, target));
         run_cargo(builder,
                   &mut cargo,
+                  vec![],
                   &librustc_stamp(builder, compiler, target),
                   true);
 
@@ -144,6 +146,7 @@ impl Step for CodegenBackend {
         let _folder = builder.fold_output(|| format!("stage{}-rustc_codegen_llvm", compiler.stage));
         run_cargo(builder,
                   &mut cargo,
+                  vec![],
                   &codegen_backend_stamp(builder, compiler, target, backend),
                   true);
     }
@@ -181,6 +184,7 @@ impl Step for Test {
         builder.info(&format!("Checking test artifacts ({} -> {})", &compiler.host, target));
         run_cargo(builder,
                   &mut cargo,
+                  vec![],
                   &libtest_stamp(builder, compiler, target),
                   true);
 
@@ -228,6 +232,7 @@ impl Step for Rustdoc {
         println!("Checking rustdoc artifacts ({} -> {})", &compiler.host, target);
         run_cargo(builder,
                   &mut cargo,
+                  vec![],
                   &rustdoc_stamp(builder, compiler, target),
                   true);
 
diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index 366df4b0ad5..61a04b97206 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -29,7 +29,6 @@ use build_helper::{output, mtime, up_to_date};
 use filetime::FileTime;
 use serde_json;
 
-use crate::dist;
 use crate::util::{exe, libdir, is_dylib};
 use crate::{Compiler, Mode, GitRepo};
 use crate::native;
@@ -115,6 +114,7 @@ impl Step for Std {
                 &compiler.host, target));
         run_cargo(builder,
                   &mut cargo,
+                  vec![],
                   &libstd_stamp(builder, compiler, target),
                   false);
 
@@ -375,6 +375,7 @@ impl Step for Test {
                 &compiler.host, target));
         run_cargo(builder,
                   &mut cargo,
+                  vec![],
                   &libtest_stamp(builder, compiler, target),
                   false);
 
@@ -502,6 +503,7 @@ impl Step for Rustc {
                  compiler.stage, &compiler.host, target));
         run_cargo(builder,
                   &mut cargo,
+                  vec![],
                   &librustc_stamp(builder, compiler, target),
                   false);
 
@@ -644,18 +646,47 @@ impl Step for CodegenBackend {
 
         let out_dir = builder.cargo_out(compiler, Mode::Codegen, target);
 
-        let mut cargo = builder.cargo(compiler, Mode::Codegen, target, "build");
+        let mut cargo = builder.cargo(compiler, Mode::Codegen, target, "rustc");
         cargo.arg("--manifest-path")
             .arg(builder.src.join("src/librustc_codegen_llvm/Cargo.toml"));
         rustc_cargo_env(builder, &mut cargo);
 
         let features = build_codegen_backend(&builder, &mut cargo, &compiler, target, backend);
 
+        let mut cargo_tails_args = vec![];
+
+        if builder.config.llvm_thin_lto {
+            cargo_tails_args.push("--".to_string());
+
+            let num_jobs = builder.jobs();
+
+            if !target.contains("msvc") {
+                // Here we assume that the linker is clang. If it's not, there'll
+                // be linker errors.
+                cargo_tails_args.push("-Clink-arg=-fuse-ld=lld".to_string());
+                cargo_tails_args.push("-Clink-arg=-flto=thin".to_string());
+
+                if builder.config.llvm_optimize {
+                    cargo_tails_args.push("-Clink-arg=-O2".to_string());
+                }
+
+                // Let's make LLD respect the `-j` option.
+                let num_jobs_arg = format!("-Clink-arg=-Wl,--thinlto-jobs={}", num_jobs);
+                cargo_tails_args.push(num_jobs_arg);
+            } else {
+                // Here we assume that the linker is lld-link.exe. lld-link.exe
+                // does not need the extra arguments except for num_jobs
+                let num_jobs_arg = format!("-Clink-arg=/opt:lldltojobs={}", num_jobs);
+                cargo_tails_args.push(num_jobs_arg);
+            }
+        }
+
         let tmp_stamp = out_dir.join(".tmp.stamp");
 
         let _folder = builder.fold_output(|| format!("stage{}-rustc_codegen_llvm", compiler.stage));
         let files = run_cargo(builder,
                               cargo.arg("--features").arg(features),
+                              cargo_tails_args,
                               &tmp_stamp,
                               false);
         if builder.config.dry_run {
@@ -728,9 +759,7 @@ pub fn build_codegen_backend(builder: &Builder,
                                          "libstdc++.a");
                 cargo.env("LLVM_STATIC_STDCPP", file);
             }
-            if builder.config.llvm_link_shared ||
-                (builder.config.llvm_thin_lto && backend != "emscripten")
-            {
+            if builder.config.llvm_link_shared {
                 cargo.env("LLVM_LINK_SHARED", "1");
             }
         }
@@ -970,8 +999,6 @@ impl Step for Assemble {
             copy_lld_to_sysroot(builder, target_compiler, &lld_install);
         }
 
-        dist::maybe_install_llvm_dylib(builder, target_compiler.host, &sysroot);
-
         // Link the compiler binary itself into place
         let out_dir = builder.cargo_out(build_compiler, Mode::Rustc, host);
         let rustc = out_dir.join(exe("rustc_binary", &*host));
@@ -998,6 +1025,7 @@ pub fn add_to_sysroot(builder: &Builder, sysroot_dst: &Path, stamp: &Path) {
 
 pub fn run_cargo(builder: &Builder,
                  cargo: &mut Command,
+                 tail_args: Vec<String>,
                  stamp: &Path,
                  is_check: bool)
     -> Vec<PathBuf>
@@ -1020,7 +1048,7 @@ pub fn run_cargo(builder: &Builder,
     // files we need to probe for later.
     let mut deps = Vec::new();
     let mut toplevel = Vec::new();
-    let ok = stream_cargo(builder, cargo, &mut |msg| {
+    let ok = stream_cargo(builder, cargo, tail_args, &mut |msg| {
         let filenames = match msg {
             CargoMessage::CompilerArtifact { filenames, .. } => filenames,
             _ => return,
@@ -1145,6 +1173,7 @@ pub fn run_cargo(builder: &Builder,
 pub fn stream_cargo(
     builder: &Builder,
     cargo: &mut Command,
+    tail_args: Vec<String>,
     cb: &mut dyn FnMut(CargoMessage),
 ) -> bool {
     if builder.config.dry_run {
@@ -1155,6 +1184,10 @@ pub fn stream_cargo(
     cargo.arg("--message-format").arg("json")
          .stdout(Stdio::piped());
 
+    for arg in tail_args {
+        cargo.arg(arg);
+    }
+
     builder.verbose(&format!("running: {:?}", cargo));
     let mut child = match cargo.spawn() {
         Ok(child) => child,
diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index e38a1d29545..f6f4d608465 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -1887,13 +1887,13 @@ impl Step for HashSign {
 // LLVM tools are linked dynamically.
 // Note: This function does no yet support Windows but we also don't support
 //       linking LLVM tools dynamically on Windows yet.
-pub fn maybe_install_llvm_dylib(builder: &Builder,
-                                target: Interned<String>,
-                                sysroot: &Path) {
+fn maybe_install_llvm_dylib(builder: &Builder,
+                            target: Interned<String>,
+                            image: &Path) {
     let src_libdir = builder
         .llvm_out(target)
         .join("lib");
-    let dst_libdir = sysroot.join("lib/rustlib").join(&*target).join("lib");
+    let dst_libdir = image.join("lib/rustlib").join(&*target).join("lib");
     t!(fs::create_dir_all(&dst_libdir));
 
     if target.contains("apple-darwin") {
diff --git a/src/bootstrap/tool.rs b/src/bootstrap/tool.rs
index d2fc26e5812..4335359e115 100644
--- a/src/bootstrap/tool.rs
+++ b/src/bootstrap/tool.rs
@@ -87,7 +87,7 @@ impl Step for ToolBuild {
         let _folder = builder.fold_output(|| format!("stage{}-{}", compiler.stage, tool));
         builder.info(&format!("Building stage{} tool {} ({})", compiler.stage, tool, target));
         let mut duplicates = Vec::new();
-        let is_expected = compile::stream_cargo(builder, &mut cargo, &mut |msg| {
+        let is_expected = compile::stream_cargo(builder, &mut cargo, vec![], &mut |msg| {
             // Only care about big things like the RLS/Cargo for now
             match tool {
                 | "rls"
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index b56ae61227c..6c1417741f2 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -210,7 +210,14 @@ pub fn run<F>(run_compiler: F) -> isize
 }
 
 fn load_backend_from_dylib(path: &Path) -> fn() -> Box<dyn CodegenBackend> {
-    let lib = DynamicLibrary::open(Some(path)).unwrap_or_else(|err| {
+    // Note that we're specifically using `open_global_now` here rather than
+    // `open`, namely we want the behavior on Unix of RTLD_GLOBAL and RTLD_NOW,
+    // where NOW means "bind everything right now" because we don't want
+    // surprises later on and RTLD_GLOBAL allows the symbols to be made
+    // available for future dynamic libraries opened. This is currently used by
+    // loading LLVM and then making its symbols available for other dynamic
+    // libraries.
+    let lib = DynamicLibrary::open_global_now(path).unwrap_or_else(|err| {
         let err = format!("couldn't load codegen backend {:?}: {:?}", path, err);
         early_error(ErrorOutputType::default(), &err);
     });
diff --git a/src/librustc_llvm/build.rs b/src/librustc_llvm/build.rs
index 1b645389337..ce482087bba 100644
--- a/src/librustc_llvm/build.rs
+++ b/src/librustc_llvm/build.rs
@@ -142,10 +142,6 @@ fn main() {
             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;
diff --git a/src/test/run-make-fulldeps/llvm-pass/Makefile b/src/test/run-make-fulldeps/llvm-pass/Makefile
new file mode 100644
index 00000000000..8a18aadf36a
--- /dev/null
+++ b/src/test/run-make-fulldeps/llvm-pass/Makefile
@@ -0,0 +1,28 @@
+-include ../tools.mk
+
+ifeq ($(UNAME),Darwin)
+PLUGIN_FLAGS := -C link-args=-Wl,-undefined,dynamic_lookup
+endif
+
+ifeq ($(findstring stage1,$(RUST_BUILD_STAGE)),stage1)
+# ignore stage1
+all:
+
+else
+# Windows doesn't correctly handle include statements with escaping paths,
+# so this test will not get run on Windows.
+ifdef IS_WINDOWS
+all:
+else
+all: $(call NATIVE_STATICLIB,llvm-function-pass) $(call NATIVE_STATICLIB,llvm-module-pass)
+	$(RUSTC) plugin.rs -C prefer-dynamic $(PLUGIN_FLAGS)
+	$(RUSTC) main.rs
+
+$(TMPDIR)/libllvm-function-pass.o:
+	$(CXX) $(CFLAGS) $(LLVM_CXXFLAGS) -c llvm-function-pass.so.cc -o $(TMPDIR)/libllvm-function-pass.o
+
+$(TMPDIR)/libllvm-module-pass.o:
+	$(CXX) $(CFLAGS) $(LLVM_CXXFLAGS) -c llvm-module-pass.so.cc -o $(TMPDIR)/libllvm-module-pass.o
+endif
+
+endif
diff --git a/src/test/run-make-fulldeps/llvm-pass/llvm-function-pass.so.cc b/src/test/run-make-fulldeps/llvm-pass/llvm-function-pass.so.cc
new file mode 100644
index 00000000000..c0a17d920cf
--- /dev/null
+++ b/src/test/run-make-fulldeps/llvm-pass/llvm-function-pass.so.cc
@@ -0,0 +1,56 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "llvm/Pass.h"
+#include "llvm/IR/Function.h"
+
+using namespace llvm;
+
+namespace {
+
+  class TestLLVMPass : public FunctionPass {
+
+  public:
+
+    static char ID;
+    TestLLVMPass() : FunctionPass(ID) { }
+
+    bool runOnFunction(Function &F) override;
+
+    StringRef getPassName() const override {
+      return "Some LLVM pass";
+    }
+
+  };
+
+}
+
+bool TestLLVMPass::runOnFunction(Function &F) {
+  // A couple examples of operations that previously caused segmentation faults
+  // https://github.com/rust-lang/rust/issues/31067
+
+  for (auto N = F.begin(); N != F.end(); ++N) {
+    /* code */
+  }
+
+  LLVMContext &C = F.getContext();
+  IntegerType *Int8Ty  = IntegerType::getInt8Ty(C);
+  PointerType::get(Int8Ty, 0);
+  return true;
+}
+
+char TestLLVMPass::ID = 0;
+
+static RegisterPass<TestLLVMPass> RegisterAFLPass(
+  "some-llvm-function-pass", "Some LLVM pass");
diff --git a/src/test/run-make-fulldeps/llvm-pass/llvm-module-pass.so.cc b/src/test/run-make-fulldeps/llvm-pass/llvm-module-pass.so.cc
new file mode 100644
index 00000000000..70051681ab0
--- /dev/null
+++ b/src/test/run-make-fulldeps/llvm-pass/llvm-module-pass.so.cc
@@ -0,0 +1,55 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "llvm/IR/Module.h"
+
+using namespace llvm;
+
+namespace {
+
+  class TestLLVMPass : public ModulePass {
+
+  public:
+
+    static char ID;
+    TestLLVMPass() : ModulePass(ID) { }
+
+    bool runOnModule(Module &M) override;
+
+    StringRef getPassName() const override {
+      return "Some LLVM pass";
+    }
+
+  };
+
+}
+
+bool TestLLVMPass::runOnModule(Module &M) {
+  // A couple examples of operations that previously caused segmentation faults
+  // https://github.com/rust-lang/rust/issues/31067
+
+  for (auto F = M.begin(); F != M.end(); ++F) {
+    /* code */
+  }
+
+  LLVMContext &C = M.getContext();
+  IntegerType *Int8Ty  = IntegerType::getInt8Ty(C);
+  PointerType::get(Int8Ty, 0);
+  return true;
+}
+
+char TestLLVMPass::ID = 0;
+
+static RegisterPass<TestLLVMPass> RegisterAFLPass(
+  "some-llvm-module-pass", "Some LLVM pass");
diff --git a/src/test/run-make-fulldeps/llvm-pass/main.rs b/src/test/run-make-fulldeps/llvm-pass/main.rs
new file mode 100644
index 00000000000..5b5ab94bcef
--- /dev/null
+++ b/src/test/run-make-fulldeps/llvm-pass/main.rs
@@ -0,0 +1,14 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(plugin)]
+#![plugin(some_plugin)]
+
+fn main() {}
diff --git a/src/test/run-make-fulldeps/llvm-pass/plugin.rs b/src/test/run-make-fulldeps/llvm-pass/plugin.rs
new file mode 100644
index 00000000000..f77b2fca857
--- /dev/null
+++ b/src/test/run-make-fulldeps/llvm-pass/plugin.rs
@@ -0,0 +1,28 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(plugin_registrar, rustc_private)]
+#![crate_type = "dylib"]
+#![crate_name = "some_plugin"]
+
+extern crate rustc;
+extern crate rustc_plugin;
+
+#[link(name = "llvm-function-pass", kind = "static")]
+#[link(name = "llvm-module-pass", kind = "static")]
+extern {}
+
+use rustc_plugin::registry::Registry;
+
+#[plugin_registrar]
+pub fn plugin_registrar(reg: &mut Registry) {
+    reg.register_llvm_pass("some-llvm-function-pass");
+    reg.register_llvm_pass("some-llvm-module-pass");
+}