Rollup merge of #123436 - amyspark:allow-msvc-to-use-meson-and-mingw-import-libraries, r=petrochenkov

linker: Allow MSVC to use import libraries following the Meson/MinGW convention

Hi all,

This PR implements support for `MsvcLinker` to use import libraries following Meson and the MinGW toolchain's naming convention. Meson [follows the `libfoo.dll.a` naming convention](https://mesonbuild.com/FAQ.html#why-does-building-my-project-with-msvc-output-static-libraries-called-libfooa) to disambiguate between static and import libraries.

This support already existed for static libraries (see #100101), but not for dynamic libraries. The latter case was added by duplicating the logic in `native_libs::find_native_static_library`, but a separate case was added in `link_dylib_by_name` for the Windows CRT libraries which must be handled by the linker itself.

See for prerequisites #129366, #126094, and #128370.

All feedback is appreciated!

Fixes #122455

cc `@sdroege` `@nirbheek`

1 files changed, 10 insertions, 2 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs
index 7f5f9f03868..bda22255705 100644
--- a/compiler/rustc_codegen_ssa/src/back/linker.rs
+++ b/compiler/rustc_codegen_ssa/src/back/linker.rs
@@ -7,7 +7,9 @@ use std::{env, iter, mem, str};
 
 use cc::windows_registry;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
-use rustc_metadata::{find_native_static_library, try_find_native_static_library};
+use rustc_metadata::{
+    find_native_static_library, try_find_native_dynamic_library, try_find_native_static_library,
+};
 use rustc_middle::bug;
 use rustc_middle::middle::dependency_format::Linkage;
 use rustc_middle::middle::exported_symbols;
@@ -876,7 +878,13 @@ impl<'a> Linker for MsvcLinker<'a> {
     }
 
     fn link_dylib_by_name(&mut self, name: &str, verbatim: bool, _as_needed: bool) {
-        self.link_arg(format!("{}{}", name, if verbatim { "" } else { ".lib" }));
+        // On MSVC-like targets rustc supports import libraries using alternative naming
+        // scheme (`libfoo.a`) unsupported by linker, search for such libraries manually.
+        if let Some(path) = try_find_native_dynamic_library(self.sess, name, verbatim) {
+            self.link_arg(path);
+        } else {
+            self.link_arg(format!("{}{}", name, if verbatim { "" } else { ".lib" }));
+        }
     }
 
     fn link_dylib_by_path(&mut self, path: &Path, _as_needed: bool) {