Auto merge of #75483 - mati865:mingw-lld-flags, r=petrochenkov

Add LLD flags for MinGW

Tested locally and this now works:
- `RUSTFLAGS="-Zlink-self-contained=yes -Clinker=rust-lld" cargo b`
- `RUSTFLAGS="-Zlink-self-contained=no -Clinker=rust-lld -Zpre-link-arg=-Ld:/msys64/mingw64/x86_64-w64-mingw32/lib -Zpre-link-arg=-Ld:/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/10.2.0 -Zpre-link-arg=crt2.o" cargo b`

This is "harmless" part of the changes to make possible linking with bare LLD with windows-gnu target. More debatable changes should follow in next PRs soon.

src/librustc_target/spec/i686_pc_windows_gnu.rs

@@ -1,8 +1,10 @@
-use crate::spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_gnu_base::opts();
     base.cpu = "pentium4".to_string();
+    base.pre_link_args
+        .insert(LinkerFlavor::Lld(LldFlavor::Ld), vec!["-m".to_string(), "i386pe".to_string()]);
     base.max_atomic_width = Some(64);
     base.eliminate_frame_pointer = false; // Required for backtraces
     base.linker = Some("i686-w64-mingw32-gcc".to_string());

src/librustc_target/spec/i686_uwp_windows_gnu.rs

@@ -1,8 +1,10 @@
-use crate::spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_uwp_gnu_base::opts();
     base.cpu = "pentium4".to_string();
+    base.pre_link_args
+        .insert(LinkerFlavor::Lld(LldFlavor::Ld), vec!["-m".to_string(), "i386pe".to_string()]);
     base.max_atomic_width = Some(64);
     base.eliminate_frame_pointer = false; // Required for backtraces
 

src/librustc_target/spec/windows_gnu_base.rs

@@ -1,5 +1,5 @@
 use crate::spec::crt_objects::{self, CrtObjectsFallback};
-use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
 
 pub fn opts() -> TargetOptions {
     let mut pre_link_args = LinkArgs::new();
@@ -19,51 +19,48 @@ pub fn opts() -> TargetOptions {
     let mut late_link_args_static = LinkArgs::new();
     // Order of `late_link_args*` was found through trial and error to work with various
     // mingw-w64 versions (not tested on the CI). It's expected to change from time to time.
-    late_link_args.insert(
-        LinkerFlavor::Gcc,
-        vec![
-            "-lmsvcrt".to_string(),
-            "-lmingwex".to_string(),
-            "-lmingw32".to_string(),
-            // mingw's msvcrt is a weird hybrid import library and static library.
-            // And it seems that the linker fails to use import symbols from msvcrt
-            // that are required from functions in msvcrt in certain cases. For example
-            // `_fmode` that is used by an implementation of `__p__fmode` in x86_64.
-            // The library is purposely listed twice to fix that.
-            //
-            // See https://github.com/rust-lang/rust/pull/47483 for some more details.
-            "-lmsvcrt".to_string(),
-            "-luser32".to_string(),
-            "-lkernel32".to_string(),
-        ],
-    );
-    late_link_args_dynamic.insert(
-        LinkerFlavor::Gcc,
-        vec![
-            // If any of our crates are dynamically linked then we need to use
-            // the shared libgcc_s-dw2-1.dll. This is required to support
-            // unwinding across DLL boundaries.
-            "-lgcc_s".to_string(),
-            "-lgcc".to_string(),
-            "-lkernel32".to_string(),
-        ],
-    );
-    late_link_args_static.insert(
-        LinkerFlavor::Gcc,
-        vec![
-            // If all of our crates are statically linked then we can get away
-            // with statically linking the libgcc unwinding code. This allows
-            // binaries to be redistributed without the libgcc_s-dw2-1.dll
-            // dependency, but unfortunately break unwinding across DLL
-            // boundaries when unwinding across FFI boundaries.
-            "-lgcc_eh".to_string(),
-            "-l:libpthread.a".to_string(),
-            "-lgcc".to_string(),
-            // libpthread depends on libmsvcrt, so we need to link it *again*.
-            "-lmsvcrt".to_string(),
-            "-lkernel32".to_string(),
-        ],
-    );
+    let mingw_libs = vec![
+        "-lmsvcrt".to_string(),
+        "-lmingwex".to_string(),
+        "-lmingw32".to_string(),
+        // mingw's msvcrt is a weird hybrid import library and static library.
+        // And it seems that the linker fails to use import symbols from msvcrt
+        // that are required from functions in msvcrt in certain cases. For example
+        // `_fmode` that is used by an implementation of `__p__fmode` in x86_64.
+        // The library is purposely listed twice to fix that.
+        //
+        // See https://github.com/rust-lang/rust/pull/47483 for some more details.
+        "-lmsvcrt".to_string(),
+        "-luser32".to_string(),
+        "-lkernel32".to_string(),
+    ];
+    late_link_args.insert(LinkerFlavor::Gcc, mingw_libs.clone());
+    late_link_args.insert(LinkerFlavor::Lld(LldFlavor::Ld), mingw_libs);
+    let dynamic_unwind_libs = vec![
+        // If any of our crates are dynamically linked then we need to use
+        // the shared libgcc_s-dw2-1.dll. This is required to support
+        // unwinding across DLL boundaries.
+        "-lgcc_s".to_string(),
+        "-lgcc".to_string(),
+        "-lkernel32".to_string(),
+    ];
+    late_link_args_dynamic.insert(LinkerFlavor::Gcc, dynamic_unwind_libs.clone());
+    late_link_args_dynamic.insert(LinkerFlavor::Lld(LldFlavor::Ld), dynamic_unwind_libs);
+    let static_unwind_libs = vec![
+        // If all of our crates are statically linked then we can get away
+        // with statically linking the libgcc unwinding code. This allows
+        // binaries to be redistributed without the libgcc_s-dw2-1.dll
+        // dependency, but unfortunately break unwinding across DLL
+        // boundaries when unwinding across FFI boundaries.
+        "-lgcc_eh".to_string(),
+        "-l:libpthread.a".to_string(),
+        "-lgcc".to_string(),
+        // libpthread depends on libmsvcrt, so we need to link it *again*.
+        "-lmsvcrt".to_string(),
+        "-lkernel32".to_string(),
+    ];
+    late_link_args_static.insert(LinkerFlavor::Gcc, static_unwind_libs.clone());
+    late_link_args_static.insert(LinkerFlavor::Lld(LldFlavor::Ld), static_unwind_libs);
 
     TargetOptions {
         // FIXME(#13846) this should be enabled for windows

src/librustc_target/spec/windows_uwp_gnu_base.rs

@@ -1,4 +1,4 @@
-use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
 
 pub fn opts() -> TargetOptions {
     let base = super::windows_gnu_base::opts();
@@ -8,22 +8,21 @@ pub fn opts() -> TargetOptions {
     let mut late_link_args = LinkArgs::new();
     let late_link_args_dynamic = LinkArgs::new();
     let late_link_args_static = LinkArgs::new();
-    late_link_args.insert(
-        LinkerFlavor::Gcc,
-        vec![
-            //"-lwinstorecompat".to_string(),
-            //"-lmingwex".to_string(),
-            //"-lwinstorecompat".to_string(),
-            "-lwinstorecompat".to_string(),
-            "-lruntimeobject".to_string(),
-            "-lsynchronization".to_string(),
-            "-lvcruntime140_app".to_string(),
-            "-lucrt".to_string(),
-            "-lwindowsapp".to_string(),
-            "-lmingwex".to_string(),
-            "-lmingw32".to_string(),
-        ],
-    );
+    let mingw_libs = vec![
+        //"-lwinstorecompat".to_string(),
+        //"-lmingwex".to_string(),
+        //"-lwinstorecompat".to_string(),
+        "-lwinstorecompat".to_string(),
+        "-lruntimeobject".to_string(),
+        "-lsynchronization".to_string(),
+        "-lvcruntime140_app".to_string(),
+        "-lucrt".to_string(),
+        "-lwindowsapp".to_string(),
+        "-lmingwex".to_string(),
+        "-lmingw32".to_string(),
+    ];
+    late_link_args.insert(LinkerFlavor::Gcc, mingw_libs.clone());
+    late_link_args.insert(LinkerFlavor::Lld(LldFlavor::Ld), mingw_libs.clone());
 
     TargetOptions {
         executables: false,

src/librustc_target/spec/x86_64_pc_windows_gnu.rs

@@ -1,9 +1,11 @@
-use crate::spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_gnu_base::opts();
     base.cpu = "x86-64".to_string();
     base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args
+        .insert(LinkerFlavor::Lld(LldFlavor::Ld), vec!["-m".to_string(), "i386pep".to_string()]);
     base.max_atomic_width = Some(64);
     base.linker = Some("x86_64-w64-mingw32-gcc".to_string());
 

src/librustc_target/spec/x86_64_uwp_windows_gnu.rs

@@ -1,9 +1,11 @@
-use crate::spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_uwp_gnu_base::opts();
     base.cpu = "x86-64".to_string();
     base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args
+        .insert(LinkerFlavor::Lld(LldFlavor::Ld), vec!["-m".to_string(), "i386pep".to_string()]);
     base.max_atomic_width = Some(64);
 
     Ok(Target {