MsvcLinker: allow linking dynamically to Meson and MinGW-style named libraries

Fixes#122455

Author: amyspark

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;
@@ -878,7 +880,13 @@ impl<'a> Linker for MsvcLinker<'a> {
 }
 
 fnlink_dylib_by_name(&mutself,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.
+ifletSome(path) = try_find_native_dynamic_library(self.sess, name, verbatim){
+self.link_arg(path);
+}else{
+self.link_arg(format!("{}{}", name,if verbatim {""} else {".lib"}));
+}
 }
 
 fnlink_dylib_by_path(&mutself,path:&Path,_as_needed:bool){

compiler/rustc_metadata/src/lib.rs

@@ -37,7 +37,8 @@ pub mod locator;
 pubuse creader::{load_symbol_from_dylib,DylibError};
 pubuse fs::{emit_wrapper_file,METADATA_FILENAME};
 pubuse native_libs::{
- find_native_static_library, try_find_native_static_library, walk_native_lib_search_dirs,
+ find_native_static_library, try_find_native_dynamic_library, try_find_native_static_library,
+ walk_native_lib_search_dirs,
 };
 pubuse rmeta::{encode_metadata, rendered_const,EncodedMetadata,METADATA_HEADER};
 

compiler/rustc_metadata/src/native_libs.rs

@@ -109,6 +109,44 @@ pub fn try_find_native_static_library(
 .break_value()
 }
 
+pubfntry_find_native_dynamic_library(
+sess:&Session,
+name:&str,
+verbatim:bool,
+) -> Option<PathBuf>{
+let formats = if verbatim {
+vec![("".into(),"".into())]
+}else{
+// While the official naming convention for MSVC import libraries
+// is foo.lib...
+let os = (sess.target.staticlib_prefix.clone(), sess.target.staticlib_suffix.clone());
+// ... Meson follows the libfoo.dll.a convention to
+// disambiguate .a for static libraries
+let meson = ("lib".into(),".dll.a".into());
+// and MinGW uses .a altogether
+let mingw = ("lib".into(),".a".into());
+vec![os, meson, mingw]
+};
+
+walk_native_lib_search_dirs(
+ sess,
+LinkSelfContainedComponents::empty(),
+None,
+ |dir, is_framework| {
+if !is_framework {
+for(prefix, suffix)in&formats {
+let test = dir.join(format!("{prefix}{name}{suffix}"));
+if test.exists(){
+returnControlFlow::Break(test);
+}
+}
+}
+ControlFlow::Continue(())
+},
+)
+.break_value()
+}
+
 pubfnfind_native_static_library(name:&str,verbatim:bool,sess:&Session) -> PathBuf{
 try_find_native_static_library(sess, name, verbatim)
 .unwrap_or_else(|| sess.dcx().emit_fatal(errors::MissingNativeLibrary::new(name, verbatim)))