linker: Refactor APIs for linking dynamic libraries

Rename `link_(dylib,framework)`, remove `link_rust_dylib`.

Author: petrochenkov

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -1265,7 +1265,7 @@ fn link_sanitizer_runtime(
         let path = find_sanitizer_runtime(sess, &filename);
         let rpath = path.to_str().expect("non-utf8 component in path");
         linker.args(&["-Wl,-rpath", "-Xlinker", rpath]);
-        linker.link_dylib(&filename, false, true);
+        linker.link_dylib_by_name(&filename, false, true);
     } else if sess.target.is_like_msvc && flavor == LinkerFlavor::Msvc(Lld::No) && name == "asan" {
         // MSVC provides the `/INFERASANLIBS` argument to automatically find the
         // compatible ASAN library.
@@ -2526,7 +2526,7 @@ fn add_native_libs_from_crate(
             }
             NativeLibKind::Dylib { as_needed } => {
                 if link_dynamic {
-                    cmd.link_dylib(name, verbatim, as_needed.unwrap_or(true))
+                    cmd.link_dylib_by_name(name, verbatim, as_needed.unwrap_or(true))
                 }
             }
             NativeLibKind::Unspecified => {
@@ -2538,13 +2538,13 @@ fn add_native_libs_from_crate(
                     }
                 } else {
                     if link_dynamic {
-                        cmd.link_dylib(name, verbatim, true);
+                        cmd.link_dylib_by_name(name, verbatim, true);
                     }
                 }
             }
             NativeLibKind::Framework { as_needed } => {
                 if link_dynamic {
-                    cmd.link_framework(name, as_needed.unwrap_or(true))
+                    cmd.link_framework_by_name(name, verbatim, as_needed.unwrap_or(true))
                 }
             }
             NativeLibKind::RawDylib => {
@@ -2859,13 +2859,20 @@ fn add_dynamic_crate(cmd: &mut dyn Linker, sess: &Session, cratepath: &Path) {
     // Just need to tell the linker about where the library lives and
     // what its name is
     let parent = cratepath.parent();
+    // When producing a dll, the MSVC linker may not actually emit a
+    // `foo.lib` file if the dll doesn't actually export any symbols, so we
+    // check to see if the file is there and just omit linking to it if it's
+    // not present.
+    if sess.target.is_like_msvc && !cratepath.with_extension("dll.lib").exists() {
+        return;
+    }
     if let Some(dir) = parent {
         cmd.include_path(&rehome_sysroot_lib_dir(sess, dir));
     }
     let stem = cratepath.file_stem().unwrap().to_str().unwrap();
     // Convert library file-stem into a cc -l argument.
     let prefix = if stem.starts_with("lib") && !sess.target.is_like_windows { 3 } else { 0 };
-    cmd.link_rust_dylib(&stem[prefix..], parent.unwrap_or_else(|| Path::new("")));
+    cmd.link_dylib_by_name(&stem[prefix..], false, true);
 }
 
 fn relevant_lib(sess: &Session, lib: &NativeLib) -> bool {

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -166,9 +166,10 @@ pub fn get_linker<'a>(
 pub trait Linker {
     fn cmd(&mut self) -> &mut Command;
     fn set_output_kind(&mut self, output_kind: LinkOutputKind, out_filename: &Path);
-    fn link_dylib(&mut self, lib: &str, verbatim: bool, as_needed: bool);
-    fn link_rust_dylib(&mut self, lib: &str, path: &Path);
-    fn link_framework(&mut self, framework: &str, as_needed: bool);
+    fn link_dylib_by_name(&mut self, name: &str, verbatim: bool, as_needed: bool);
+    fn link_framework_by_name(&mut self, _name: &str, _verbatim: bool, _as_needed: bool) {
+        bug!("framework linked with unsupported linker")
+    }
     fn link_staticlib(&mut self, lib: &str, verbatim: bool);
     fn link_rlib(&mut self, lib: &Path);
     fn link_whole_rlib(&mut self, lib: &Path);
@@ -432,8 +433,8 @@ impl<'a> Linker for GccLinker<'a> {
         }
     }
 
-    fn link_dylib(&mut self, lib: &str, verbatim: bool, as_needed: bool) {
-        if self.sess.target.os == "illumos" && lib == "c" {
+    fn link_dylib_by_name(&mut self, name: &str, verbatim: bool, as_needed: bool) {
+        if self.sess.target.os == "illumos" && name == "c" {
             // libc will be added via late_link_args on illumos so that it will
             // appear last in the library search order.
             // FIXME: This should be replaced by a more complete and generic
@@ -454,7 +455,7 @@ impl<'a> Linker for GccLinker<'a> {
             }
         }
         self.hint_dynamic();
-        self.cmd.arg(format!("-l{}{lib}", if verbatim && self.is_gnu { ":" } else { "" },));
+        self.cmd.arg(format!("-l{}{name}", if verbatim && self.is_gnu { ":" } else { "" },));
         if !as_needed {
             if self.sess.target.is_like_osx {
                 // See above FIXME comment
@@ -493,20 +494,15 @@ impl<'a> Linker for GccLinker<'a> {
         self.linker_args(&["-z", "norelro"]);
     }
 
-    fn link_rust_dylib(&mut self, lib: &str, _path: &Path) {
-        self.hint_dynamic();
-        self.cmd.arg(format!("-l{lib}"));
-    }
-
-    fn link_framework(&mut self, framework: &str, as_needed: bool) {
+    fn link_framework_by_name(&mut self, name: &str, _verbatim: bool, as_needed: bool) {
         self.hint_dynamic();
         if !as_needed {
             // FIXME(81490): ld64 as of macOS 11 supports the -needed_framework
             // flag but we have no way to detect that here.
-            // self.cmd.arg("-needed_framework").arg(framework);
+            // self.cmd.arg("-needed_framework").arg(name);
             self.sess.dcx().emit_warn(errors::Ld64UnimplementedModifier);
         }
-        self.cmd.arg("-framework").arg(framework);
+        self.cmd.arg("-framework").arg(name);
     }
 
     // Here we explicitly ask that the entire archive is included into the
@@ -845,19 +841,8 @@ impl<'a> Linker for MsvcLinker<'a> {
         self.cmd.arg("/OPT:NOREF,NOICF");
     }
 
-    fn link_dylib(&mut self, lib: &str, verbatim: bool, _as_needed: bool) {
-        self.cmd.arg(format!("{}{}", lib, if verbatim { "" } else { ".lib" }));
-    }
-
-    fn link_rust_dylib(&mut self, lib: &str, path: &Path) {
-        // When producing a dll, the MSVC linker may not actually emit a
-        // `foo.lib` file if the dll doesn't actually export any symbols, so we
-        // check to see if the file is there and just omit linking to it if it's
-        // not present.
-        let name = format!("{lib}.dll.lib");
-        if path.join(&name).exists() {
-            self.cmd.arg(name);
-        }
+    fn link_dylib_by_name(&mut self, name: &str, verbatim: bool, _as_needed: bool) {
+        self.cmd.arg(format!("{}{}", name, if verbatim { "" } else { ".lib" }));
     }
 
     fn link_staticlib(&mut self, lib: &str, verbatim: bool) {
@@ -899,9 +884,6 @@ impl<'a> Linker for MsvcLinker<'a> {
     fn framework_path(&mut self, _path: &Path) {
         bug!("frameworks are not supported on windows")
     }
-    fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
-        bug!("frameworks are not supported on windows")
-    }
 
     fn link_whole_staticlib(&mut self, lib: &str, verbatim: bool, _search_path: &[PathBuf]) {
         self.cmd.arg(format!("/WHOLEARCHIVE:{}{}", lib, if verbatim { "" } else { ".lib" }));
@@ -1073,9 +1055,9 @@ impl<'a> Linker for EmLinker<'a> {
         self.cmd.arg(path);
     }
 
-    fn link_dylib(&mut self, lib: &str, verbatim: bool, _as_needed: bool) {
+    fn link_dylib_by_name(&mut self, name: &str, verbatim: bool, _as_needed: bool) {
         // Emscripten always links statically
-        self.link_staticlib(lib, verbatim);
+        self.link_staticlib(name, verbatim);
     }
 
     fn link_whole_staticlib(&mut self, lib: &str, verbatim: bool, _search_path: &[PathBuf]) {
@@ -1088,10 +1070,6 @@ impl<'a> Linker for EmLinker<'a> {
         self.link_rlib(lib);
     }
 
-    fn link_rust_dylib(&mut self, lib: &str, _path: &Path) {
-        self.link_dylib(lib, false, true);
-    }
-
     fn link_rlib(&mut self, lib: &Path) {
         self.add_object(lib);
     }
@@ -1112,10 +1090,6 @@ impl<'a> Linker for EmLinker<'a> {
         bug!("frameworks are not supported on Emscripten")
     }
 
-    fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
-        bug!("frameworks are not supported on Emscripten")
-    }
-
     fn gc_sections(&mut self, _keep_metadata: bool) {
         // noop
     }
@@ -1249,8 +1223,8 @@ impl<'a> Linker for WasmLd<'a> {
         }
     }
 
-    fn link_dylib(&mut self, lib: &str, _verbatim: bool, _as_needed: bool) {
-        self.cmd.arg("-l").arg(lib);
+    fn link_dylib_by_name(&mut self, name: &str, _verbatim: bool, _as_needed: bool) {
+        self.cmd.arg("-l").arg(name);
     }
 
     fn link_staticlib(&mut self, lib: &str, _verbatim: bool) {
@@ -1283,14 +1257,6 @@ impl<'a> Linker for WasmLd<'a> {
 
     fn no_relro(&mut self) {}
 
-    fn link_rust_dylib(&mut self, lib: &str, _path: &Path) {
-        self.cmd.arg("-l").arg(lib);
-    }
-
-    fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
-        panic!("frameworks not supported")
-    }
-
     fn link_whole_staticlib(&mut self, lib: &str, _verbatim: bool, _search_path: &[PathBuf]) {
         self.cmd.arg("--whole-archive").arg("-l").arg(lib).arg("--no-whole-archive");
     }
@@ -1398,7 +1364,7 @@ pub struct L4Bender<'a> {
 }
 
 impl<'a> Linker for L4Bender<'a> {
-    fn link_dylib(&mut self, _lib: &str, _verbatim: bool, _as_needed: bool) {
+    fn link_dylib_by_name(&mut self, _name: &str, _verbatim: bool, _as_needed: bool) {
         bug!("dylibs are not supported on L4Re");
     }
     fn link_staticlib(&mut self, lib: &str, _verbatim: bool) {
@@ -1442,14 +1408,6 @@ impl<'a> Linker for L4Bender<'a> {
 
     fn set_output_kind(&mut self, _output_kind: LinkOutputKind, _out_filename: &Path) {}
 
-    fn link_rust_dylib(&mut self, _: &str, _: &Path) {
-        panic!("Rust dylibs not supported");
-    }
-
-    fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
-        bug!("frameworks not supported on L4Re");
-    }
-
     fn link_whole_staticlib(&mut self, lib: &str, _verbatim: bool, _search_path: &[PathBuf]) {
         self.hint_static();
         self.cmd.arg("--whole-archive").arg(format!("-l{lib}"));
@@ -1571,9 +1529,9 @@ impl<'a> AixLinker<'a> {
 }
 
 impl<'a> Linker for AixLinker<'a> {
-    fn link_dylib(&mut self, lib: &str, _verbatim: bool, _as_needed: bool) {
+    fn link_dylib_by_name(&mut self, name: &str, _verbatim: bool, _as_needed: bool) {
         self.hint_dynamic();
-        self.cmd.arg(format!("-l{lib}"));
+        self.cmd.arg(format!("-l{name}"));
     }
 
     fn link_staticlib(&mut self, lib: &str, _verbatim: bool) {
@@ -1626,15 +1584,6 @@ impl<'a> Linker for AixLinker<'a> {
         }
     }
 
-    fn link_rust_dylib(&mut self, lib: &str, _: &Path) {
-        self.hint_dynamic();
-        self.cmd.arg(format!("-l{lib}"));
-    }
-
-    fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
-        bug!("frameworks not supported on AIX");
-    }
-
     fn link_whole_staticlib(&mut self, lib: &str, verbatim: bool, search_path: &[PathBuf]) {
         self.hint_static();
         let lib = find_native_static_library(lib, verbatim, search_path, self.sess);
@@ -1844,11 +1793,7 @@ impl<'a> Linker for PtxLinker<'a> {
         self.cmd.arg("-o").arg(path);
     }
 
-    fn link_dylib(&mut self, _lib: &str, _verbatim: bool, _as_needed: bool) {
-        panic!("external dylibs not supported")
-    }
-
-    fn link_rust_dylib(&mut self, _lib: &str, _path: &Path) {
+    fn link_dylib_by_name(&mut self, _name: &str, _verbatim: bool, _as_needed: bool) {
         panic!("external dylibs not supported")
     }
 
@@ -1864,10 +1809,6 @@ impl<'a> Linker for PtxLinker<'a> {
         panic!("frameworks not supported")
     }
 
-    fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
-        panic!("frameworks not supported")
-    }
-
     fn full_relro(&mut self) {}
 
     fn partial_relro(&mut self) {}
@@ -1942,11 +1883,7 @@ impl<'a> Linker for BpfLinker<'a> {
         self.cmd.arg("-o").arg(path);
     }
 
-    fn link_dylib(&mut self, _lib: &str, _verbatim: bool, _as_needed: bool) {
-        panic!("external dylibs not supported")
-    }
-
-    fn link_rust_dylib(&mut self, _lib: &str, _path: &Path) {
+    fn link_dylib_by_name(&mut self, _name: &str, _verbatim: bool, _as_needed: bool) {
         panic!("external dylibs not supported")
     }
 
@@ -1962,10 +1899,6 @@ impl<'a> Linker for BpfLinker<'a> {
         panic!("frameworks not supported")
     }
 
-    fn link_framework(&mut self, _framework: &str, _as_needed: bool) {
-        panic!("frameworks not supported")
-    }
-
     fn full_relro(&mut self) {}
 
     fn partial_relro(&mut self) {}