Merge pull request #154 from amyspark/fix-windows-library-detection

Fix Windows static library detection and usage

Author: sdroege

src/lib.rs

@@ -776,34 +776,38 @@ impl Library {
         }
 
         let prefix = "lib";
-        if target.contains("msvc") {
-            // According to link.exe documentation:
-            // https://learn.microsoft.com/en-us/cpp/build/reference/link-input-files?view=msvc-170
-            //
-            //   LINK doesn't use file extensions to make assumptions about the contents of a file.
-            //   Instead, LINK examines each input file to determine what kind of file it is.
-            //
-            // However, rustc appends `.lib` to the string it receives from the -l command line argument,
-            // which it receives from Cargo via cargo:rustc-link-lib:
-            // https://github.com/rust-lang/rust/blob/657f246812ab2684e3c3954b1c77f98fd59e0b21/compiler/rustc_codegen_ssa/src/back/linker.rs#L828
-            // https://github.com/rust-lang/rust/blob/657f246812ab2684e3c3954b1c77f98fd59e0b21/compiler/rustc_codegen_ssa/src/back/linker.rs#L843
-            // So the only file extension that works for MSVC targets is `.lib`
-            return test_suffixes(filename, &[".lib"]);
-        } else if target.contains("windows") && target.contains("gnu") {
-            // GNU targets for Windows, including gnullvm, use `LinkerFlavor::Gcc` internally in rustc,
-            // which tells rustc to use the GNU linker. rustc does not prepend/append to the string it
-            // receives via the -l command line argument before passing it to the linker:
-            // https://github.com/rust-lang/rust/blob/657f246812ab2684e3c3954b1c77f98fd59e0b21/compiler/rustc_codegen_ssa/src/back/linker.rs#L446
-            // https://github.com/rust-lang/rust/blob/657f246812ab2684e3c3954b1c77f98fd59e0b21/compiler/rustc_codegen_ssa/src/back/linker.rs#L457
-            // GNU ld can work with more types of files than just the .lib files that MSVC's link.exe needs.
-            // GNU ld will prepend the `lib` prefix to the filename if necessary, so it is okay to remove
-            // the `lib` prefix from the filename. The `.a` suffix *requires* the `lib` prefix.
-            // https://sourceware.org/binutils/docs-2.39/ld.html#index-direct-linking-to-a-dll
-            if filename.starts_with(prefix) {
+        if target.contains("windows") {
+            if target.contains("gnu") && filename.starts_with(prefix) {
+                // GNU targets for Windows, including gnullvm, use `LinkerFlavor::Gcc` internally in rustc,
+                // which tells rustc to use the GNU linker. rustc does not prepend/append to the string it
+                // receives via the -l command line argument before passing it to the linker:
+                // https://github.com/rust-lang/rust/blob/657f246812ab2684e3c3954b1c77f98fd59e0b21/compiler/rustc_codegen_ssa/src/back/linker.rs#L446
+                // https://github.com/rust-lang/rust/blob/657f246812ab2684e3c3954b1c77f98fd59e0b21/compiler/rustc_codegen_ssa/src/back/linker.rs#L457
+                // GNU ld can work with more types of files than just the .lib files that MSVC's link.exe needs.
+                // GNU ld will prepend the `lib` prefix to the filename if necessary, so it is okay to remove
+                // the `lib` prefix from the filename. The `.a` suffix *requires* the `lib` prefix.
+                // https://sourceware.org/binutils/docs-2.39/ld.html#index-direct-linking-to-a-dll
                 let filename = &filename[prefix.len()..];
                 return test_suffixes(filename, &[".dll.a", ".dll", ".lib", ".a"]);
             } else {
-                return test_suffixes(filename, &[".dll.a", ".dll", ".lib"]);
+                // According to link.exe documentation:
+                // https://learn.microsoft.com/en-us/cpp/build/reference/link-input-files?view=msvc-170
+                //
+                //   LINK doesn't use file extensions to make assumptions about the contents of a file.
+                //   Instead, LINK examines each input file to determine what kind of file it is.
+                //
+                // However, rustc appends `.lib` to the string it receives from the -l command line argument,
+                // which it receives from Cargo via cargo:rustc-link-lib:
+                // https://github.com/rust-lang/rust/blob/657f246812ab2684e3c3954b1c77f98fd59e0b21/compiler/rustc_codegen_ssa/src/back/linker.rs#L828
+                // https://github.com/rust-lang/rust/blob/657f246812ab2684e3c3954b1c77f98fd59e0b21/compiler/rustc_codegen_ssa/src/back/linker.rs#L843
+                // So the only file extension that works for MSVC targets is `.lib`
+                // However, for externally created libraries, there's no
+                // guarantee that the extension is ".lib" so we need to
+                // consider all options.
+                // See:
+                // https://github.com/mesonbuild/meson/issues/8153
+                // https://github.com/rust-lang/rust/issues/114013
+                return test_suffixes(filename, &[".dll.a", ".dll", ".lib", ".a"]);
             }
         } else if target.contains("apple") {
             if filename.starts_with(prefix) {
@@ -901,6 +905,10 @@ impl Library {
                         iter.next().map(|s| s.to_owned()),
                     );
                 }
+                "-u" => {
+                    let meta = format!("rustc-link-arg=-Wl,-u,{}", val);
+                    config.print_metadata(&meta);
+                }
                 _ => {}
             }
         }
@@ -927,6 +935,12 @@ impl Library {
                         self.include_paths.push(PathBuf::from(inc));
                     }
                 }
+                "-undefined" | "--undefined" => {
+                    if let Some(symbol) = iter.next() {
+                        let meta = format!("rustc-link-arg=-Wl,{},{}", part, symbol);
+                        config.print_metadata(&meta);
+                    }
+                }
                 _ => {
                     let path = std::path::Path::new(part);
                     if path.is_file() {
@@ -1000,10 +1014,19 @@ fn envify(name: &str) -> String {
 
 /// System libraries should only be linked dynamically
 fn is_static_available(name: &str, system_roots: &[PathBuf], dirs: &[PathBuf]) -> bool {
-    let libname = format!("lib{}.a", name);
+    let libnames = {
+        let mut names = vec![format!("lib{}.a", name)];
+
+        if cfg!(target_os = "windows") {
+            names.push(format!("{}.lib", name));
+        }
+
+        names
+    };
 
     dirs.iter().any(|dir| {
-        !system_roots.iter().any(|sys| dir.starts_with(sys)) && dir.join(&libname).exists()
+        let library_exists = libnames.iter().any(|libname| dir.join(&libname).exists());
+        library_exists && !system_roots.iter().any(|sys| dir.starts_with(sys))
     })
 }