linker: Move native library search from linker to rustc

For static libraries only, for now.
Linker's search by name is still used if rustc's search fails, because linker may search in additional platform-specific directories in addition to directories known to rustc.

Author: petrochenkov

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -6,9 +6,7 @@ use std::{env, io, 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_dynamic_library, try_find_native_static_library,
-};
+use rustc_metadata::{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;
@@ -615,15 +613,15 @@ impl<'a> Linker for GccLinker<'a> {
     }
 
     fn link_staticlib_by_name(&mut self, name: &str, verbatim: bool, whole_archive: bool) {
+        if let Some(path) = try_find_native_static_library(self.sess, name, verbatim) {
+            return self.link_staticlib_by_path(&path, whole_archive);
+        }
         self.hint_static();
         let colon = if verbatim && self.is_gnu { ":" } else { "" };
         if !whole_archive {
             self.link_or_cc_arg(format!("-l{colon}{name}"));
         } else if self.sess.target.is_like_darwin {
-            // -force_load is the macOS equivalent of --whole-archive, but it
-            // involves passing the full path to the library to link.
-            self.link_arg("-force_load");
-            self.link_arg(find_native_static_library(name, verbatim, self.sess));
+            self.link_args(&["-force_load", name]);
         } else {
             self.link_arg("--whole-archive")
                 .link_or_cc_arg(format!("-l{colon}{name}"))
@@ -956,15 +954,12 @@ impl<'a> Linker for MsvcLinker<'a> {
     }
 
     fn link_staticlib_by_name(&mut self, name: &str, verbatim: bool, whole_archive: bool) {
-        // On MSVC-like targets rustc supports static libraries using alternative naming
-        // scheme (`libfoo.a`) unsupported by linker, search for such libraries manually.
         if let Some(path) = try_find_native_static_library(self.sess, name, verbatim) {
-            self.link_staticlib_by_path(&path, whole_archive);
-        } else {
-            let opts = if whole_archive { "/WHOLEARCHIVE:" } else { "" };
-            let (prefix, suffix) = self.sess.staticlib_components(verbatim);
-            self.link_arg(format!("{opts}{prefix}{name}{suffix}"));
+            return self.link_staticlib_by_path(&path, whole_archive);
         }
+        let opts = if whole_archive { "/WHOLEARCHIVE:" } else { "" };
+        let (prefix, suffix) = self.sess.staticlib_components(verbatim);
+        self.link_arg(format!("{opts}{prefix}{name}{suffix}"));
     }
 
     fn link_staticlib_by_path(&mut self, path: &Path, whole_archive: bool) {
@@ -1193,7 +1188,10 @@ impl<'a> Linker for EmLinker<'a> {
         self.link_or_cc_arg(path);
     }
 
-    fn link_staticlib_by_name(&mut self, name: &str, _verbatim: bool, _whole_archive: bool) {
+    fn link_staticlib_by_name(&mut self, name: &str, verbatim: bool, whole_archive: bool) {
+        if let Some(path) = try_find_native_static_library(self.sess, name, verbatim) {
+            return self.link_staticlib_by_path(&path, whole_archive);
+        }
         self.link_or_cc_args(&["-l", name]);
     }
 
@@ -1359,7 +1357,10 @@ impl<'a> Linker for WasmLd<'a> {
         self.link_or_cc_arg(path);
     }
 
-    fn link_staticlib_by_name(&mut self, name: &str, _verbatim: bool, whole_archive: bool) {
+    fn link_staticlib_by_name(&mut self, name: &str, verbatim: bool, whole_archive: bool) {
+        if let Some(path) = try_find_native_static_library(self.sess, name, verbatim) {
+            return self.link_staticlib_by_path(&path, whole_archive);
+        }
         if !whole_archive {
             self.link_or_cc_args(&["-l", name]);
         } else {
@@ -1493,7 +1494,10 @@ impl<'a> Linker for L4Bender<'a> {
     ) {
     }
 
-    fn link_staticlib_by_name(&mut self, name: &str, _verbatim: bool, whole_archive: bool) {
+    fn link_staticlib_by_name(&mut self, name: &str, verbatim: bool, whole_archive: bool) {
+        if let Some(path) = try_find_native_static_library(self.sess, name, verbatim) {
+            return self.link_staticlib_by_path(&path, whole_archive);
+        }
         self.hint_static();
         if !whole_archive {
             self.link_arg(format!("-PC{name}"));
@@ -1667,12 +1671,15 @@ impl<'a> Linker for AixLinker<'a> {
     }
 
     fn link_staticlib_by_name(&mut self, name: &str, verbatim: bool, whole_archive: bool) {
+        if let Some(path) = try_find_native_static_library(self.sess, name, verbatim) {
+            return self.link_staticlib_by_path(&path, whole_archive);
+        }
         self.hint_static();
         if !whole_archive {
             self.link_or_cc_arg(if verbatim { String::from(name) } else { format!("-l{name}") });
         } else {
             let mut arg = OsString::from("-bkeepfile:");
-            arg.push(find_native_static_library(name, verbatim, self.sess));
+            arg.push(name);
             self.link_or_cc_arg(arg);
         }
     }

src/doc/rustc/src/command-line-arguments.md

@@ -82,6 +82,12 @@ The name used in a `link` attribute may be overridden using the form `-l
 ATTR_NAME:LINK_NAME` where `ATTR_NAME` is the name in the `link` attribute,
 and `LINK_NAME` is the name of the actual library that will be linked.
 
+The compiler may attempt to search for the library in native library search directories
+(controlled by `-L`), and pass it to linker by full path if the search is successful.
+Otherwise the library will be passed to linker by name, so it can perform its own search.
+In some cases this enables use of alternative library naming schemes or `+verbatim` modifier
+even if they are not natively supported by linker.
+
 [link-attribute]: ../reference/items/external-blocks.html#the-link-attribute
 
 ### Linking modifiers: `whole-archive`

tests/run-make/native-link-modifier-bundle/rmake.rs

@@ -68,7 +68,7 @@ fn main() {
             .crate_type("cdylib")
             .print("link-args")
             .run()
-            .assert_stdout_not_contains(r#"-l[" ]*native-staticlib"#);
+            .assert_stdout_not_contains("libnative-staticlib.a");
         llvm_nm()
             .input(dynamic_lib_name("cdylib_bundled"))
             .run()
@@ -81,7 +81,7 @@ fn main() {
             .crate_type("cdylib")
             .print("link-args")
             .run()
-            .assert_stdout_contains_regex(r#"-l[" ]*native-staticlib"#);
+            .assert_stdout_contains_regex(r"libnative-staticlib.a");
         llvm_nm()
             .input(dynamic_lib_name("cdylib_non_bundled"))
             .run()

tests/run-make/native-link-modifier-verbatim-linker/rmake.rs

@@ -4,9 +4,6 @@
 // See https://github.com/rust-lang/rust/issues/99425
 
 //@ ignore-cross-compile
-//@ ignore-apple
-//@ ignore-wasm
-// Reason: linking fails due to the unusual ".ext" staticlib name.
 
 use run_make_support::rustc;