Merge from rust-lang/rust

16 files changed, 441 insertions, 113 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 892dfb91201..e7b1c63a822 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -40,7 +40,7 @@ use rustc_target::spec::crt_objects::CrtObjects;
 use rustc_target::spec::{
     Cc, LinkOutputKind, LinkSelfContainedComponents, LinkSelfContainedDefault, LinkerFeatures,
     LinkerFlavor, LinkerFlavorCli, Lld, PanicStrategy, RelocModel, RelroLevel, SanitizerSet,
-    SplitDebuginfo,
+    SplitDebuginfo, current_apple_deployment_target,
 };
 use tempfile::Builder as TempFileBuilder;
 use tracing::{debug, info, warn};
@@ -1087,16 +1087,17 @@ fn link_natively(
     let strip = sess.opts.cg.strip;
 
     if sess.target.is_like_osx {
+        let stripcmd = "/usr/bin/strip";
         match (strip, crate_type) {
             (Strip::Debuginfo, _) => {
-                strip_symbols_with_external_utility(sess, "strip", out_filename, Some("-S"))
+                strip_symbols_with_external_utility(sess, stripcmd, out_filename, Some("-S"))
             }
             // Per the manpage, `-x` is the maximum safe strip level for dynamic libraries. (#93988)
             (Strip::Symbols, CrateType::Dylib | CrateType::Cdylib | CrateType::ProcMacro) => {
-                strip_symbols_with_external_utility(sess, "strip", out_filename, Some("-x"))
+                strip_symbols_with_external_utility(sess, stripcmd, out_filename, Some("-x"))
             }
             (Strip::Symbols, _) => {
-                strip_symbols_with_external_utility(sess, "strip", out_filename, None)
+                strip_symbols_with_external_utility(sess, stripcmd, out_filename, None)
             }
             (Strip::None, _) => {}
         }
@@ -2404,6 +2405,8 @@ fn add_order_independent_options(
     // Take care of the flavors and CLI options requesting the `lld` linker.
     add_lld_args(cmd, sess, flavor, self_contained_components);
 
+    add_apple_link_args(cmd, sess, flavor);
+
     let apple_sdk_root = add_apple_sdk(cmd, sess, flavor);
 
     add_link_script(cmd, sess, tmpdir, crate_type);
@@ -2487,7 +2490,7 @@ fn add_order_independent_options(
         }
     }
 
-    cmd.set_output_kind(link_output_kind, out_filename);
+    cmd.set_output_kind(link_output_kind, crate_type, out_filename);
 
     add_relro_args(cmd, sess);
 
@@ -2956,6 +2959,169 @@ pub(crate) fn are_upstream_rust_objects_already_included(sess: &Session) -> bool
     }
 }
 
+/// We need to communicate five things to the linker on Apple/Darwin targets:
+/// - The architecture.
+/// - The operating system (and that it's an Apple platform).
+/// - The environment / ABI.
+/// - The deployment target.
+/// - The SDK version.
+fn add_apple_link_args(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
+    if !sess.target.is_like_osx {
+        return;
+    }
+    let LinkerFlavor::Darwin(cc, _) = flavor else {
+        return;
+    };
+
+    // `sess.target.arch` (`target_arch`) is not detailed enough.
+    let llvm_arch = sess.target.llvm_target.split_once('-').expect("LLVM target must have arch").0;
+    let target_os = &*sess.target.os;
+    let target_abi = &*sess.target.abi;
+
+    // The architecture name to forward to the linker.
+    //
+    // Supported architecture names can be found in the source:
+    // https://github.com/apple-oss-distributions/ld64/blob/ld64-951.9/src/abstraction/MachOFileAbstraction.hpp#L578-L648
+    //
+    // Intentially verbose to ensure that the list always matches correctly
+    // with the list in the source above.
+    let ld64_arch = match llvm_arch {
+        "armv7k" => "armv7k",
+        "armv7s" => "armv7s",
+        "arm64" => "arm64",
+        "arm64e" => "arm64e",
+        "arm64_32" => "arm64_32",
+        // ld64 doesn't understand i686, so fall back to i386 instead.
+        //
+        // Same story when linking with cc, since that ends up invoking ld64.
+        "i386" | "i686" => "i386",
+        "x86_64" => "x86_64",
+        "x86_64h" => "x86_64h",
+        _ => bug!("unsupported architecture in Apple target: {}", sess.target.llvm_target),
+    };
+
+    if cc == Cc::No {
+        // From the man page for ld64 (`man ld`):
+        // > The linker accepts universal (multiple-architecture) input files,
+        // > but always creates a "thin" (single-architecture), standard
+        // > Mach-O output file. The architecture for the output file is
+        // > specified using the -arch option.
+        //
+        // The linker has heuristics to determine the desired architecture,
+        // but to be safe, and to avoid a warning, we set the architecture
+        // explicitly.
+        cmd.link_args(&["-arch", ld64_arch]);
+
+        // Man page says that ld64 supports the following platform names:
+        // > - macos
+        // > - ios
+        // > - tvos
+        // > - watchos
+        // > - bridgeos
+        // > - visionos
+        // > - xros
+        // > - mac-catalyst
+        // > - ios-simulator
+        // > - tvos-simulator
+        // > - watchos-simulator
+        // > - visionos-simulator
+        // > - xros-simulator
+        // > - driverkit
+        let platform_name = match (target_os, target_abi) {
+            (os, "") => os,
+            ("ios", "macabi") => "mac-catalyst",
+            ("ios", "sim") => "ios-simulator",
+            ("tvos", "sim") => "tvos-simulator",
+            ("watchos", "sim") => "watchos-simulator",
+            ("visionos", "sim") => "visionos-simulator",
+            _ => bug!("invalid OS/ABI combination for Apple target: {target_os}, {target_abi}"),
+        };
+
+        let (major, minor, patch) = current_apple_deployment_target(&sess.target);
+        let min_version = format!("{major}.{minor}.{patch}");
+
+        // The SDK version is used at runtime when compiling with a newer SDK / version of Xcode:
+        // - By dyld to give extra warnings and errors, see e.g.:
+        //   <https://github.com/apple-oss-distributions/dyld/blob/dyld-1165.3/common/MachOFile.cpp#L3029>
+        //   <https://github.com/apple-oss-distributions/dyld/blob/dyld-1165.3/common/MachOFile.cpp#L3738-L3857>
+        // - By system frameworks to change certain behaviour. For example, the default value of
+        //   `-[NSView wantsBestResolutionOpenGLSurface]` is `YES` when the SDK version is >= 10.15.
+        //   <https://developer.apple.com/documentation/appkit/nsview/1414938-wantsbestresolutionopenglsurface?language=objc>
+        //
+        // We do not currently know the actual SDK version though, so we have a few options:
+        // 1. Use the minimum version supported by rustc.
+        // 2. Use the same as the deployment target.
+        // 3. Use an arbitary recent version.
+        // 4. Omit the version.
+        //
+        // The first option is too low / too conservative, and means that users will not get the
+        // same behaviour from a binary compiled with rustc as with one compiled by clang.
+        //
+        // The second option is similarly conservative, and also wrong since if the user specified a
+        // higher deployment target than the SDK they're compiling/linking with, the runtime might
+        // make invalid assumptions about the capabilities of the binary.
+        //
+        // The third option requires that `rustc` is periodically kept up to date with Apple's SDK
+        // version, and is also wrong for similar reasons as above.
+        //
+        // The fourth option is bad because while `ld`, `otool`, `vtool` and such understand it to
+        // mean "absent" or `n/a`, dyld doesn't actually understand it, and will end up interpreting
+        // it as 0.0, which is again too low/conservative.
+        //
+        // Currently, we lie about the SDK version, and choose the second option.
+        //
+        // FIXME(madsmtm): Parse the SDK version from the SDK root instead.
+        // <https://github.com/rust-lang/rust/issues/129432>
+        let sdk_version = &*min_version;
+
+        // From the man page for ld64 (`man ld`):
+        // > This is set to indicate the platform, oldest supported version of
+        // > that platform that output is to be used on, and the SDK that the
+        // > output was built against.
+        //
+        // Like with `-arch`, the linker can figure out the platform versions
+        // itself from the binaries being linked, but to be safe, we specify
+        // the desired versions here explicitly.
+        cmd.link_args(&["-platform_version", platform_name, &*min_version, sdk_version]);
+    } else {
+        // cc == Cc::Yes
+        //
+        // We'd _like_ to use `-target` everywhere, since that can uniquely
+        // communicate all the required details except for the SDK version
+        // (which is read by Clang itself from the SDKROOT), but that doesn't
+        // work on GCC, and since we don't know whether the `cc` compiler is
+        // Clang, GCC, or something else, we fall back to other options that
+        // also work on GCC when compiling for macOS.
+        //
+        // Targets other than macOS are ill-supported by GCC (it doesn't even
+        // support e.g. `-miphoneos-version-min`), so in those cases we can
+        // fairly safely use `-target`. See also the following, where it is
+        // made explicit that the recommendation by LLVM developers is to use
+        // `-target`: <https://github.com/llvm/llvm-project/issues/88271>
+        if target_os == "macos" {
+            // `-arch` communicates the architecture.
+            //
+            // CC forwards the `-arch` to the linker, so we use the same value
+            // here intentionally.
+            cmd.cc_args(&["-arch", ld64_arch]);
+
+            // The presence of `-mmacosx-version-min` makes CC default to
+            // macOS, and it sets the deployment target.
+            let (major, minor, patch) = current_apple_deployment_target(&sess.target);
+            // Intentionally pass this as a single argument, Clang doesn't
+            // seem to like it otherwise.
+            cmd.cc_arg(&format!("-mmacosx-version-min={major}.{minor}.{patch}"));
+
+            // macOS has no environment, so with these two, we've told CC the
+            // four desired parameters.
+            //
+            // We avoid `-m32`/`-m64`, as this is already encoded by `-arch`.
+        } else {
+            cmd.cc_args(&["-target", &sess.target.llvm_target]);
+        }
+    }
+}
+
 fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) -> Option<PathBuf> {
     let arch = &sess.target.arch;
     let os = &sess.target.os;
diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs
index 84817e19844..3f3d305da01 100644
--- a/compiler/rustc_codegen_ssa/src/back/linker.rs
+++ b/compiler/rustc_codegen_ssa/src/back/linker.rs
@@ -1,9 +1,8 @@
 use std::ffi::{OsStr, OsString};
 use std::fs::{self, File};
 use std::io::prelude::*;
-use std::io::{self, BufWriter};
 use std::path::{Path, PathBuf};
-use std::{env, iter, mem, str};
+use std::{env, io, iter, mem, str};
 
 use cc::windows_registry;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
@@ -276,7 +275,12 @@ pub(crate) trait Linker {
     fn is_cc(&self) -> bool {
         false
     }
-    fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path);
+    fn set_output_kind(
+        &mut self,
+        output_kind: LinkOutputKind,
+        crate_type: CrateType,
+        out_filename: &Path,
+    );
     fn link_dylib_by_name(&mut self, _name: &str, _verbatim: bool, _as_needed: bool) {
         bug!("dylib linked with unsupported linker")
     }
@@ -397,7 +401,7 @@ impl<'a> GccLinker<'a> {
         ]);
     }
 
-    fn build_dylib(&mut self, out_filename: &Path) {
+    fn build_dylib(&mut self, crate_type: CrateType, out_filename: &Path) {
         // On mac we need to tell the linker to let this library be rpathed
         if self.sess.target.is_like_osx {
             if !self.is_ld {
@@ -428,7 +432,7 @@ impl<'a> GccLinker<'a> {
                     let mut out_implib = OsString::from("--out-implib=");
                     out_implib.push(out_filename.with_file_name(implib_name));
                     self.link_arg(out_implib);
-                } else {
+                } else if crate_type == CrateType::Dylib {
                     // When dylibs are linked by a full path this value will get into `DT_NEEDED`
                     // instead of the full path, so the library can be later found in some other
                     // location than that specific path.
@@ -475,7 +479,12 @@ impl<'a> Linker for GccLinker<'a> {
         !self.is_ld
     }
 
-    fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path) {
+    fn set_output_kind(
+        &mut self,
+        output_kind: LinkOutputKind,
+        crate_type: CrateType,
+        out_filename: &Path,
+    ) {
         match output_kind {
             LinkOutputKind::DynamicNoPicExe => {
                 if !self.is_ld && self.is_gnu {
@@ -510,10 +519,10 @@ impl<'a> Linker for GccLinker<'a> {
                     self.link_args(&["-static", "-pie", "--no-dynamic-linker", "-z", "text"]);
                 }
             }
-            LinkOutputKind::DynamicDylib => self.build_dylib(out_filename),
+            LinkOutputKind::DynamicDylib => self.build_dylib(crate_type, out_filename),
             LinkOutputKind::StaticDylib => {
                 self.link_or_cc_arg("-static");
-                self.build_dylib(out_filename);
+                self.build_dylib(crate_type, out_filename);
             }
             LinkOutputKind::WasiReactorExe => {
                 self.link_args(&["--entry", "_initialize"]);
@@ -754,7 +763,7 @@ impl<'a> Linker for GccLinker<'a> {
         if self.sess.target.is_like_osx {
             // Write a plain, newline-separated list of symbols
             let res: io::Result<()> = try {
-                let mut f = BufWriter::new(File::create(&path)?);
+                let mut f = File::create_buffered(&path)?;
                 for sym in symbols {
                     debug!("  _{sym}");
                     writeln!(f, "_{sym}")?;
@@ -765,7 +774,7 @@ impl<'a> Linker for GccLinker<'a> {
             }
         } else if is_windows {
             let res: io::Result<()> = try {
-                let mut f = BufWriter::new(File::create(&path)?);
+                let mut f = File::create_buffered(&path)?;
 
                 // .def file similar to MSVC one but without LIBRARY section
                 // because LD doesn't like when it's empty
@@ -781,7 +790,7 @@ impl<'a> Linker for GccLinker<'a> {
         } else {
             // Write an LD version script
             let res: io::Result<()> = try {
-                let mut f = BufWriter::new(File::create(&path)?);
+                let mut f = File::create_buffered(&path)?;
                 writeln!(f, "{{")?;
                 if !symbols.is_empty() {
                     writeln!(f, "  global:")?;
@@ -867,7 +876,12 @@ impl<'a> Linker for MsvcLinker<'a> {
         &mut self.cmd
     }
 
-    fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path) {
+    fn set_output_kind(
+        &mut self,
+        output_kind: LinkOutputKind,
+        _crate_type: CrateType,
+        out_filename: &Path,
+    ) {
         match output_kind {
             LinkOutputKind::DynamicNoPicExe
             | LinkOutputKind::DynamicPicExe
@@ -1059,7 +1073,7 @@ impl<'a> Linker for MsvcLinker<'a> {
 
         let path = tmpdir.join("lib.def");
         let res: io::Result<()> = try {
-            let mut f = BufWriter::new(File::create(&path)?);
+            let mut f = File::create_buffered(&path)?;
 
             // Start off with the standard module name header and then go
             // straight to exports.
@@ -1125,7 +1139,13 @@ impl<'a> Linker for EmLinker<'a> {
         true
     }
 
-    fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {}
+    fn set_output_kind(
+        &mut self,
+        _output_kind: LinkOutputKind,
+        _crate_type: CrateType,
+        _out_filename: &Path,
+    ) {
+    }
 
     fn link_dylib_by_name(&mut self, name: &str, _verbatim: bool, _as_needed: bool) {
         // Emscripten always links statically
@@ -1274,7 +1294,12 @@ impl<'a> Linker for WasmLd<'a> {
         &mut self.cmd
     }
 
-    fn set_output_kind(&mut self, output_kind: LinkOutputKind, _out_filename: &Path) {
+    fn set_output_kind(
+        &mut self,
+        output_kind: LinkOutputKind,
+        _crate_type: CrateType,
+        _out_filename: &Path,
+    ) {
         match output_kind {
             LinkOutputKind::DynamicNoPicExe
             | LinkOutputKind::DynamicPicExe
@@ -1423,7 +1448,13 @@ impl<'a> Linker for L4Bender<'a> {
         &mut self.cmd
     }
 
-    fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {}
+    fn set_output_kind(
+        &mut self,
+        _output_kind: LinkOutputKind,
+        _crate_type: CrateType,
+        _out_filename: &Path,
+    ) {
+    }
 
     fn link_staticlib_by_name(&mut self, name: &str, _verbatim: bool, whole_archive: bool) {
         self.hint_static();
@@ -1569,7 +1600,12 @@ impl<'a> Linker for AixLinker<'a> {
         &mut self.cmd
     }
 
-    fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path) {
+    fn set_output_kind(
+        &mut self,
+        output_kind: LinkOutputKind,
+        _crate_type: CrateType,
+        out_filename: &Path,
+    ) {
         match output_kind {
             LinkOutputKind::DynamicDylib => {
                 self.hint_dynamic();
@@ -1648,7 +1684,7 @@ impl<'a> Linker for AixLinker<'a> {
     fn export_symbols(&mut self, tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
         let path = tmpdir.join("list.exp");
         let res: io::Result<()> = try {
-            let mut f = BufWriter::new(File::create(&path)?);
+            let mut f = File::create_buffered(&path)?;
             // FIXME: use llvm-nm to generate export list.
             for symbol in symbols {
                 debug!("  _{symbol}");
@@ -1776,7 +1812,13 @@ impl<'a> Linker for PtxLinker<'a> {
         &mut self.cmd
     }
 
-    fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {}
+    fn set_output_kind(
+        &mut self,
+        _output_kind: LinkOutputKind,
+        _crate_type: CrateType,
+        _out_filename: &Path,
+    ) {
+    }
 
     fn link_staticlib_by_name(&mut self, _name: &str, _verbatim: bool, _whole_archive: bool) {
         panic!("staticlibs not supported")
@@ -1842,7 +1884,13 @@ impl<'a> Linker for LlbcLinker<'a> {
         &mut self.cmd
     }
 
-    fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {}
+    fn set_output_kind(
+        &mut self,
+        _output_kind: LinkOutputKind,
+        _crate_type: CrateType,
+        _out_filename: &Path,
+    ) {
+    }
 
     fn link_staticlib_by_name(&mut self, _name: &str, _verbatim: bool, _whole_archive: bool) {
         panic!("staticlibs not supported")
@@ -1913,7 +1961,13 @@ impl<'a> Linker for BpfLinker<'a> {
         &mut self.cmd
     }
 
-    fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {}
+    fn set_output_kind(
+        &mut self,
+        _output_kind: LinkOutputKind,
+        _crate_type: CrateType,
+        _out_filename: &Path,
+    ) {
+    }
 
     fn link_staticlib_by_name(&mut self, _name: &str, _verbatim: bool, _whole_archive: bool) {
         panic!("staticlibs not supported")
@@ -1961,7 +2015,7 @@ impl<'a> Linker for BpfLinker<'a> {
     fn export_symbols(&mut self, tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
         let path = tmpdir.join("symbols");
         let res: io::Result<()> = try {
-            let mut f = BufWriter::new(File::create(&path)?);
+            let mut f = File::create_buffered(&path)?;
             for sym in symbols {
                 writeln!(f, "{sym}")?;
             }
diff --git a/compiler/rustc_codegen_ssa/src/back/metadata.rs b/compiler/rustc_codegen_ssa/src/back/metadata.rs
index 06433484ea3..8857fda1e97 100644
--- a/compiler/rustc_codegen_ssa/src/back/metadata.rs
+++ b/compiler/rustc_codegen_ssa/src/back/metadata.rs
@@ -402,13 +402,17 @@ fn macho_object_build_version_for_target(target: &Target) -> object::write::Mach
     let platform =
         rustc_target::spec::current_apple_platform(target).expect("unknown Apple target OS");
     let min_os = rustc_target::spec::current_apple_deployment_target(target);
-    let (sdk_major, sdk_minor) =
-        rustc_target::spec::current_apple_sdk_version(platform).expect("unknown Apple target OS");
 
     let mut build_version = object::write::MachOBuildVersion::default();
     build_version.platform = platform;
     build_version.minos = pack_version(min_os);
-    build_version.sdk = pack_version((sdk_major, sdk_minor, 0));
+    // The version here does not _really_ matter, since it is only used at runtime, and we specify
+    // it when linking the final binary, so we will omit the version. This is also what LLVM does,
+    // and the tooling also allows this (and shows the SDK version as `n/a`). Finally, it is the
+    // semantically correct choice, as the SDK has not influenced the binary generated by rustc at
+    // this point in time.
+    build_version.sdk = 0;
+
     build_version
 }
 
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index 4d81ff933dd..e22dd8373bd 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -11,7 +11,6 @@ use rustc_ast::attr;
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::profiling::{SelfProfilerRef, VerboseTimingGuard};
-use rustc_data_structures::sync::Lrc;
 use rustc_errors::emitter::Emitter;
 use rustc_errors::translation::Translate;
 use rustc_errors::{
@@ -1889,7 +1888,7 @@ impl SharedEmitter {
 }
 
 impl Translate for SharedEmitter {
-    fn fluent_bundle(&self) -> Option<&Lrc<FluentBundle>> {
+    fn fluent_bundle(&self) -> Option<&FluentBundle> {
         None
     }
 
@@ -1924,7 +1923,7 @@ impl Emitter for SharedEmitter {
         );
     }
 
-    fn source_map(&self) -> Option<&Lrc<SourceMap>> {
+    fn source_map(&self) -> Option<&SourceMap> {
         None
     }
 }
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 8e4385bee1a..d91c0f0790d 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -27,6 +27,9 @@ use rustc_session::config::{self, CrateType, EntryFnType, OptLevel, OutputType};
 use rustc_span::symbol::sym;
 use rustc_span::{DUMMY_SP, Symbol};
 use rustc_target::abi::FIRST_VARIANT;
+use rustc_trait_selection::infer::at::ToTrace;
+use rustc_trait_selection::infer::{BoundRegionConversionTime, TyCtxtInferExt};
+use rustc_trait_selection::traits::{ObligationCause, ObligationCtxt};
 use tracing::{debug, info};
 
 use crate::assert_module_sources::CguReuse;
@@ -37,6 +40,7 @@ use crate::back::write::{
     submit_codegened_module_to_llvm, submit_post_lto_module_to_llvm, submit_pre_lto_module_to_llvm,
 };
 use crate::common::{self, IntPredicate, RealPredicate, TypeKind};
+use crate::meth::load_vtable;
 use crate::mir::operand::OperandValue;
 use crate::mir::place::PlaceRef;
 use crate::traits::*;
@@ -100,6 +104,54 @@ pub fn compare_simd_types<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     bx.sext(cmp, ret_ty)
 }
 
+/// Codegen takes advantage of the additional assumption, where if the
+/// principal trait def id of what's being casted doesn't change,
+/// then we don't need to adjust the vtable at all. This
+/// corresponds to the fact that `dyn Tr<A>: Unsize<dyn Tr<B>>`
+/// requires that `A = B`; we don't allow *upcasting* objects
+/// between the same trait with different args. If we, for
+/// some reason, were to relax the `Unsize` trait, it could become
+/// unsound, so let's validate here that the trait refs are subtypes.
+pub fn validate_trivial_unsize<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    source_data: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
+    target_data: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
+) -> bool {
+    match (source_data.principal(), target_data.principal()) {
+        (Some(hr_source_principal), Some(hr_target_principal)) => {
+            let infcx = tcx.infer_ctxt().build();
+            let universe = infcx.universe();
+            let ocx = ObligationCtxt::new(&infcx);
+            infcx.enter_forall(hr_target_principal, |target_principal| {
+                let source_principal = infcx.instantiate_binder_with_fresh_vars(
+                    DUMMY_SP,
+                    BoundRegionConversionTime::HigherRankedType,
+                    hr_source_principal,
+                );
+                let Ok(()) = ocx.eq_trace(
+                    &ObligationCause::dummy(),
+                    ty::ParamEnv::reveal_all(),
+                    ToTrace::to_trace(
+                        &ObligationCause::dummy(),
+                        hr_target_principal,
+                        hr_source_principal,
+                    ),
+                    target_principal,
+                    source_principal,
+                ) else {
+                    return false;
+                };
+                if !ocx.select_all_or_error().is_empty() {
+                    return false;
+                }
+                infcx.leak_check(universe, None).is_ok()
+            })
+        }
+        (None, None) => true,
+        _ => false,
+    }
+}
+
 /// Retrieves the information we are losing (making dynamic) in an unsizing
 /// adjustment.
 ///
@@ -124,8 +176,24 @@ fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
             let old_info =
                 old_info.expect("unsized_info: missing old info for trait upcasting coercion");
             if data_a.principal_def_id() == data_b.principal_def_id() {
-                // A NOP cast that doesn't actually change anything, should be allowed even with
-                // invalid vtables.
+                // Codegen takes advantage of the additional assumption, where if the
+                // principal trait def id of what's being casted doesn't change,
+                // then we don't need to adjust the vtable at all. This
+                // corresponds to the fact that `dyn Tr<A>: Unsize<dyn Tr<B>>`
+                // requires that `A = B`; we don't allow *upcasting* objects
+                // between the same trait with different args. If we, for
+                // some reason, were to relax the `Unsize` trait, it could become
+                // unsound, so let's assert here that the trait refs are *equal*.
+                debug_assert!(
+                    validate_trivial_unsize(cx.tcx(), data_a, data_b),
+                    "NOP unsize vtable changed principal trait ref: {data_a} -> {data_b}"
+                );
+
+                // A NOP cast that doesn't actually change anything, let's avoid any
+                // unnecessary work. This relies on the assumption that if the principal
+                // traits are equal, then the associated type bounds (`dyn Trait<Assoc=T>`)
+                // are also equal, which is ensured by the fact that normalization is
+                // a function and we do not allow overlapping impls.
                 return old_info;
             }
 
@@ -135,14 +203,8 @@ fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 
             if let Some(entry_idx) = vptr_entry_idx {
                 let ptr_size = bx.data_layout().pointer_size;
-                let ptr_align = bx.data_layout().pointer_align.abi;
                 let vtable_byte_offset = u64::try_from(entry_idx).unwrap() * ptr_size.bytes();
-                let gep = bx.inbounds_ptradd(old_info, bx.const_usize(vtable_byte_offset));
-                let new_vptr = bx.load(bx.type_ptr(), gep, ptr_align);
-                bx.nonnull_metadata(new_vptr);
-                // VTable loads are invariant.
-                bx.set_invariant_load(new_vptr);
-                new_vptr
+                load_vtable(bx, old_info, bx.type_ptr(), vtable_byte_offset, source, true)
             } else {
                 old_info
             }
diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
index e99c3a46271..8d634ca4655 100644
--- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
+++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
@@ -1,4 +1,4 @@
-use rustc_ast::{MetaItemKind, NestedMetaItem, ast, attr};
+use rustc_ast::{MetaItemInner, MetaItemKind, ast, attr};
 use rustc_attr::{InlineAttr, InstructionSetAttr, OptimizeAttr, list_contains_name};
 use rustc_errors::codes::*;
 use rustc_errors::{DiagMessage, SubdiagMessage, struct_span_code_err};
@@ -357,7 +357,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
             sym::instruction_set => {
                 codegen_fn_attrs.instruction_set =
                     attr.meta_item_list().and_then(|l| match &l[..] {
-                        [NestedMetaItem::MetaItem(set)] => {
+                        [MetaItemInner::MetaItem(set)] => {
                             let segments =
                                 set.path.segments.iter().map(|x| x.ident.name).collect::<Vec<_>>();
                             match segments.as_slice() {
diff --git a/compiler/rustc_codegen_ssa/src/errors.rs b/compiler/rustc_codegen_ssa/src/errors.rs
index 08b326e3ac3..ab909abcead 100644
--- a/compiler/rustc_codegen_ssa/src/errors.rs
+++ b/compiler/rustc_codegen_ssa/src/errors.rs
@@ -916,8 +916,8 @@ pub enum InvalidMonomorphization<'tcx> {
         ret_ty: Ty<'tcx>,
     },
 
-    #[diag(codegen_ssa_invalid_monomorphization_cast_fat_pointer, code = E0511)]
-    CastFatPointer {
+    #[diag(codegen_ssa_invalid_monomorphization_cast_wide_pointer, code = E0511)]
+    CastWidePointer {
         #[primary_span]
         span: Span,
         name: Symbol,
diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
index ec0520fbb09..cbd95146294 100644
--- a/compiler/rustc_codegen_ssa/src/lib.rs
+++ b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -6,6 +6,7 @@
 #![doc(rust_logo)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
+#![feature(file_buffered)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
 #![feature(negative_impls)]
@@ -155,7 +156,7 @@ pub struct NativeLib {
     pub kind: NativeLibKind,
     pub name: Symbol,
     pub filename: Option<Symbol>,
-    pub cfg: Option<ast::MetaItem>,
+    pub cfg: Option<ast::MetaItemInner>,
     pub verbatim: bool,
     pub dll_imports: Vec<cstore::DllImport>,
 }
diff --git a/compiler/rustc_codegen_ssa/src/meth.rs b/compiler/rustc_codegen_ssa/src/meth.rs
index ecc3b2b24f1..7eb0ecd12ff 100644
--- a/compiler/rustc_codegen_ssa/src/meth.rs
+++ b/compiler/rustc_codegen_ssa/src/meth.rs
@@ -28,27 +28,9 @@ impl<'a, 'tcx> VirtualIndex {
 
         let llty = bx.fn_ptr_backend_type(fn_abi);
         let ptr_size = bx.data_layout().pointer_size;
-        let ptr_align = bx.data_layout().pointer_align.abi;
         let vtable_byte_offset = self.0 * ptr_size.bytes();
 
-        if bx.cx().sess().opts.unstable_opts.virtual_function_elimination
-            && bx.cx().sess().lto() == Lto::Fat
-        {
-            let typeid = bx
-                .typeid_metadata(typeid_for_trait_ref(bx.tcx(), expect_dyn_trait_in_self(ty)))
-                .unwrap();
-            let func = bx.type_checked_load(llvtable, vtable_byte_offset, typeid);
-            func
-        } else {
-            let gep = bx.inbounds_ptradd(llvtable, bx.const_usize(vtable_byte_offset));
-            let ptr = bx.load(llty, gep, ptr_align);
-            // VTable loads are invariant.
-            bx.set_invariant_load(ptr);
-            if nonnull {
-                bx.nonnull_metadata(ptr);
-            }
-            ptr
-        }
+        load_vtable(bx, llvtable, llty, vtable_byte_offset, ty, nonnull)
     }
 
     pub(crate) fn get_optional_fn<Bx: BuilderMethods<'a, 'tcx>>(
@@ -75,31 +57,27 @@ impl<'a, 'tcx> VirtualIndex {
         self,
         bx: &mut Bx,
         llvtable: Bx::Value,
+        ty: Ty<'tcx>,
     ) -> Bx::Value {
         // Load the data pointer from the object.
         debug!("get_int({:?}, {:?})", llvtable, self);
 
         let llty = bx.type_isize();
         let ptr_size = bx.data_layout().pointer_size;
-        let ptr_align = bx.data_layout().pointer_align.abi;
         let vtable_byte_offset = self.0 * ptr_size.bytes();
 
-        let gep = bx.inbounds_ptradd(llvtable, bx.const_usize(vtable_byte_offset));
-        let ptr = bx.load(llty, gep, ptr_align);
-        // VTable loads are invariant.
-        bx.set_invariant_load(ptr);
-        ptr
+        load_vtable(bx, llvtable, llty, vtable_byte_offset, ty, false)
     }
 }
 
 /// This takes a valid `self` receiver type and extracts the principal trait
-/// ref of the type.
-fn expect_dyn_trait_in_self(ty: Ty<'_>) -> ty::PolyExistentialTraitRef<'_> {
+/// ref of the type. Return `None` if there is no principal trait.
+fn dyn_trait_in_self(ty: Ty<'_>) -> Option<ty::PolyExistentialTraitRef<'_>> {
     for arg in ty.peel_refs().walk() {
         if let GenericArgKind::Type(ty) = arg.unpack()
             && let ty::Dynamic(data, _, _) = ty.kind()
         {
-            return data.principal().expect("expected principal trait object");
+            return data.principal();
         }
     }
 
@@ -138,3 +116,36 @@ pub(crate) fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>(
     cx.vtables().borrow_mut().insert((ty, trait_ref), vtable);
     vtable
 }
+
+/// Call this function whenever you need to load a vtable.
+pub(crate) fn load_vtable<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
+    bx: &mut Bx,
+    llvtable: Bx::Value,
+    llty: Bx::Type,
+    vtable_byte_offset: u64,
+    ty: Ty<'tcx>,
+    nonnull: bool,
+) -> Bx::Value {
+    let ptr_align = bx.data_layout().pointer_align.abi;
+
+    if bx.cx().sess().opts.unstable_opts.virtual_function_elimination
+        && bx.cx().sess().lto() == Lto::Fat
+    {
+        if let Some(trait_ref) = dyn_trait_in_self(ty) {
+            let typeid = bx.typeid_metadata(typeid_for_trait_ref(bx.tcx(), trait_ref)).unwrap();
+            let func = bx.type_checked_load(llvtable, vtable_byte_offset, typeid);
+            return func;
+        } else if nonnull {
+            bug!("load nonnull value from a vtable without a principal trait")
+        }
+    }
+
+    let gep = bx.inbounds_ptradd(llvtable, bx.const_usize(vtable_byte_offset));
+    let ptr = bx.load(llty, gep, ptr_align);
+    // VTable loads are invariant.
+    bx.set_invariant_load(ptr);
+    if nonnull {
+        bx.nonnull_metadata(ptr);
+    }
+    ptr
+}
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 125d3b908c7..be9a6d9a90e 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -3,7 +3,9 @@ use std::cmp;
 use rustc_ast as ast;
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
 use rustc_hir::lang_items::LangItem;
-use rustc_middle::mir::{self, AssertKind, BasicBlock, SwitchTargets, UnwindTerminateReason};
+use rustc_middle::mir::{
+    self, AssertKind, BasicBlock, InlineAsmMacro, SwitchTargets, UnwindTerminateReason,
+};
 use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, ValidityRequirement};
 use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths};
 use rustc_middle::ty::{self, Instance, Ty};
@@ -1133,6 +1135,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         &mut self,
         helper: TerminatorCodegenHelper<'tcx>,
         bx: &mut Bx,
+        asm_macro: InlineAsmMacro,
         terminator: &mir::Terminator<'tcx>,
         template: &[ast::InlineAsmTemplatePiece],
         operands: &[mir::InlineAsmOperand<'tcx>],
@@ -1203,11 +1206,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             &operands,
             options,
             line_spans,
-            if options.contains(InlineAsmOptions::NORETURN) {
-                None
-            } else {
-                targets.get(0).copied()
-            },
+            if asm_macro.diverges(options) { None } else { targets.get(0).copied() },
             unwind,
             instance,
             mergeable_succ,
@@ -1381,6 +1380,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             mir::TerminatorKind::InlineAsm {
+                asm_macro,
                 template,
                 ref operands,
                 options,
@@ -1390,6 +1390,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             } => self.codegen_asm_terminator(
                 helper,
                 bx,
+                asm_macro,
                 terminator,
                 template,
                 operands,
diff --git a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
index 9874809ea2b..146f55f95c2 100644
--- a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
@@ -1,4 +1,5 @@
 use std::collections::hash_map::Entry;
+use std::marker::PhantomData;
 use std::ops::Range;
 
 use rustc_data_structures::fx::FxHashMap;
@@ -14,7 +15,7 @@ use rustc_target::abi::{Abi, FieldIdx, FieldsShape, Size, VariantIdx};
 
 use super::operand::{OperandRef, OperandValue};
 use super::place::{PlaceRef, PlaceValue};
-use super::{FunctionCx, LocalRef};
+use super::{FunctionCx, LocalRef, PerLocalVarDebugInfoIndexVec};
 use crate::traits::*;
 
 pub struct FunctionDebugContext<'tcx, S, L> {
@@ -48,6 +49,17 @@ pub struct PerLocalVarDebugInfo<'tcx, D> {
     pub projection: &'tcx ty::List<mir::PlaceElem<'tcx>>,
 }
 
+/// Information needed to emit a constant.
+pub struct ConstDebugInfo<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
+    pub name: String,
+    pub source_info: mir::SourceInfo,
+    pub operand: OperandRef<'tcx, Bx::Value>,
+    pub dbg_var: Bx::DIVariable,
+    pub dbg_loc: Bx::DILocation,
+    pub fragment: Option<Range<Size>>,
+    pub _phantom: PhantomData<&'a ()>,
+}
+
 #[derive(Clone, Copy, Debug)]
 pub struct DebugScope<S, L> {
     pub dbg_scope: S,
@@ -427,11 +439,25 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         }
     }
 
-    pub(crate) fn debug_introduce_locals(&self, bx: &mut Bx) {
+    pub(crate) fn debug_introduce_locals(
+        &self,
+        bx: &mut Bx,
+        consts: Vec<ConstDebugInfo<'a, 'tcx, Bx>>,
+    ) {
         if bx.sess().opts.debuginfo == DebugInfo::Full || !bx.sess().fewer_names() {
             for local in self.locals.indices() {
                 self.debug_introduce_local(bx, local);
             }
+
+            for ConstDebugInfo { name, source_info, operand, dbg_var, dbg_loc, fragment, .. } in
+                consts.into_iter()
+            {
+                self.set_debug_loc(bx, source_info);
+                let base = FunctionCx::spill_operand_to_stack(operand, Some(name), bx);
+                bx.clear_dbg_loc();
+
+                bx.dbg_var_addr(dbg_var, dbg_loc, base.val.llval, Size::ZERO, &[], fragment);
+            }
         }
     }
 
@@ -439,7 +465,10 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub(crate) fn compute_per_local_var_debug_info(
         &self,
         bx: &mut Bx,
-    ) -> Option<IndexVec<mir::Local, Vec<PerLocalVarDebugInfo<'tcx, Bx::DIVariable>>>> {
+    ) -> Option<(
+        PerLocalVarDebugInfoIndexVec<'tcx, Bx::DIVariable>,
+        Vec<ConstDebugInfo<'a, 'tcx, Bx>>,
+    )> {
         let full_debug_info = self.cx.sess().opts.debuginfo == DebugInfo::Full;
 
         let target_is_msvc = self.cx.sess().target.is_like_msvc;
@@ -449,6 +478,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         }
 
         let mut per_local = IndexVec::from_elem(vec![], &self.mir.local_decls);
+        let mut constants = vec![];
         let mut params_seen: FxHashMap<_, Bx::DIVariable> = Default::default();
         for var in &self.mir.var_debug_info {
             let dbg_scope_and_span = if full_debug_info {
@@ -545,23 +575,19 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         let Some(dbg_loc) = self.dbg_loc(var.source_info) else { continue };
 
                         let operand = self.eval_mir_constant_to_operand(bx, &c);
-                        self.set_debug_loc(bx, var.source_info);
-                        let base =
-                            Self::spill_operand_to_stack(operand, Some(var.name.to_string()), bx);
-                        bx.clear_dbg_loc();
-
-                        bx.dbg_var_addr(
+                        constants.push(ConstDebugInfo {
+                            name: var.name.to_string(),
+                            source_info: var.source_info,
+                            operand,
                             dbg_var,
                             dbg_loc,
-                            base.val.llval,
-                            Size::ZERO,
-                            &[],
                             fragment,
-                        );
+                            _phantom: PhantomData,
+                        });
                     }
                 }
             }
         }
-        Some(per_local)
+        Some((per_local, constants))
     }
 }
diff --git a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
index 71541e6ab41..32cc78187b9 100644
--- a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
@@ -126,7 +126,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     sym::vtable_align => ty::COMMON_VTABLE_ENTRIES_ALIGN,
                     _ => bug!(),
                 };
-                let value = meth::VirtualIndex::from_index(idx).get_usize(bx, vtable);
+                let value = meth::VirtualIndex::from_index(idx).get_usize(bx, vtable, callee_ty);
                 match name {
                     // Size is always <= isize::MAX.
                     sym::vtable_size => {
diff --git a/compiler/rustc_codegen_ssa/src/mir/mod.rs b/compiler/rustc_codegen_ssa/src/mir/mod.rs
index 202baddec72..8bd172a9ce6 100644
--- a/compiler/rustc_codegen_ssa/src/mir/mod.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/mod.rs
@@ -41,6 +41,9 @@ enum CachedLlbb<T> {
     Skip,
 }
 
+type PerLocalVarDebugInfoIndexVec<'tcx, V> =
+    IndexVec<mir::Local, Vec<PerLocalVarDebugInfo<'tcx, V>>>;
+
 /// Master context for codegenning from MIR.
 pub struct FunctionCx<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
     instance: Instance<'tcx>,
@@ -107,8 +110,7 @@ pub struct FunctionCx<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
 
     /// All `VarDebugInfo` from the MIR body, partitioned by `Local`.
     /// This is `None` if no variable debuginfo/names are needed.
-    per_local_var_debug_info:
-        Option<IndexVec<mir::Local, Vec<PerLocalVarDebugInfo<'tcx, Bx::DIVariable>>>>,
+    per_local_var_debug_info: Option<PerLocalVarDebugInfoIndexVec<'tcx, Bx::DIVariable>>,
 
     /// Caller location propagated if this function has `#[track_caller]`.
     caller_location: Option<OperandRef<'tcx, Bx::Value>>,
@@ -131,9 +133,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 enum LocalRef<'tcx, V> {
     Place(PlaceRef<'tcx, V>),
     /// `UnsizedPlace(p)`: `p` itself is a thin pointer (indirect place).
-    /// `*p` is the fat pointer that references the actual unsized place.
+    /// `*p` is the wide pointer that references the actual unsized place.
     /// Every time it is initialized, we have to reallocate the place
-    /// and update the fat pointer. That's the reason why it is indirect.
+    /// and update the wide pointer. That's the reason why it is indirect.
     UnsizedPlace(PlaceRef<'tcx, V>),
     /// The backend [`OperandValue`] has already been generated.
     Operand(OperandRef<'tcx, V>),
@@ -216,7 +218,9 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     // monomorphization, and if there is an error during collection then codegen never starts -- so
     // we don't have to do it again.
 
-    fx.per_local_var_debug_info = fx.compute_per_local_var_debug_info(&mut start_bx);
+    let (per_local_var_debug_info, consts_debug_info) =
+        fx.compute_per_local_var_debug_info(&mut start_bx).unzip();
+    fx.per_local_var_debug_info = per_local_var_debug_info;
 
     let traversal_order = traversal::mono_reachable_reverse_postorder(mir, cx.tcx(), instance);
     let memory_locals = analyze::non_ssa_locals(&fx, &traversal_order);
@@ -268,7 +272,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     fx.initialize_locals(local_values);
 
     // Apply debuginfo to the newly allocated locals.
-    fx.debug_introduce_locals(&mut start_bx);
+    fx.debug_introduce_locals(&mut start_bx, consts_debug_info.unwrap_or_default());
 
     // If the backend supports coverage, and coverage is enabled for this function,
     // do any necessary start-of-function codegen (e.g. locals for MC/DC bitmaps).
@@ -425,7 +429,7 @@ fn arg_local_refs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
                 // Unsized indirect qrguments
                 PassMode::Indirect { attrs: _, meta_attrs: Some(_), on_stack: _ } => {
                     // As the storage for the indirect argument lives during
-                    // the whole function call, we just copy the fat pointer.
+                    // the whole function call, we just copy the wide pointer.
                     let llarg = bx.get_param(llarg_idx);
                     llarg_idx += 1;
                     let llextra = bx.get_param(llarg_idx);
diff --git a/compiler/rustc_codegen_ssa/src/mir/operand.rs b/compiler/rustc_codegen_ssa/src/mir/operand.rs
index 17f66c12a03..0bcd7d6d081 100644
--- a/compiler/rustc_codegen_ssa/src/mir/operand.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/operand.rs
@@ -41,7 +41,7 @@ pub enum OperandValue<V> {
     /// The backend value in this variant must be the *immediate* backend type,
     /// as returned by [`LayoutTypeCodegenMethods::immediate_backend_type`].
     Immediate(V),
-    /// A pair of immediate LLVM values. Used by fat pointers too.
+    /// A pair of immediate LLVM values. Used by wide pointers too.
     ///
     /// An `OperandValue` *must* be this variant for any type for which
     /// [`LayoutTypeCodegenMethods::is_backend_scalar_pair`] returns `true`.
diff --git a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
index f9c0f3ce941..a132ca69540 100644
--- a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
@@ -38,10 +38,10 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 ref source,
                 _,
             ) => {
-                // The destination necessarily contains a fat pointer, so if
-                // it's a scalar pair, it's a fat pointer or newtype thereof.
+                // The destination necessarily contains a wide pointer, so if
+                // it's a scalar pair, it's a wide pointer or newtype thereof.
                 if bx.cx().is_backend_scalar_pair(dest.layout) {
-                    // Into-coerce of a thin pointer to a fat pointer -- just
+                    // Into-coerce of a thin pointer to a wide pointer -- just
                     // use the operand path.
                     let temp = self.codegen_rvalue_operand(bx, rvalue);
                     temp.val.store(bx, dest);
@@ -519,7 +519,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             if bx.cx().is_backend_scalar_pair(cast) {
                                 OperandValue::Pair(data_ptr, meta)
                             } else {
-                                // Cast of fat-ptr to thin-ptr is an extraction of data-ptr.
+                                // Cast of wide-ptr to thin-ptr is an extraction of data-ptr.
                                 OperandValue::Immediate(data_ptr)
                             }
                         } else {
@@ -622,7 +622,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     (
                         OperandValue::Pair(lhs_addr, lhs_extra),
                         OperandValue::Pair(rhs_addr, rhs_extra),
-                    ) => self.codegen_fat_ptr_binop(
+                    ) => self.codegen_wide_ptr_binop(
                         bx,
                         op,
                         lhs_addr,
@@ -984,7 +984,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         }
     }
 
-    fn codegen_fat_ptr_binop(
+    fn codegen_wide_ptr_binop(
         &mut self,
         bx: &mut Bx,
         op: mir::BinOp,
@@ -1021,7 +1021,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 bx.or(lhs, rhs)
             }
             _ => {
-                bug!("unexpected fat ptr binop");
+                bug!("unexpected wide ptr binop");
             }
         }
     }
diff --git a/compiler/rustc_codegen_ssa/src/size_of_val.rs b/compiler/rustc_codegen_ssa/src/size_of_val.rs
index 3f3ae21035d..827b939217e 100644
--- a/compiler/rustc_codegen_ssa/src/size_of_val.rs
+++ b/compiler/rustc_codegen_ssa/src/size_of_val.rs
@@ -28,9 +28,9 @@ pub fn size_and_align_of_dst<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
             // Load size/align from vtable.
             let vtable = info.unwrap();
             let size = meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_SIZE)
-                .get_usize(bx, vtable);
+                .get_usize(bx, vtable, t);
             let align = meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_ALIGN)
-                .get_usize(bx, vtable);
+                .get_usize(bx, vtable, t);
 
             // Size is always <= isize::MAX.
             let size_bound = bx.data_layout().ptr_sized_integer().signed_max() as u128;