[clang] Fix --print-libgcc-file-name on Darwin platforms (PR #98325)

[Louis Dionne via cfe-commits]

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@@ -1303,18 +1288,55 @@ void MachO::AddLinkRuntimeLib(const ArgList &Args, ArgStringList &CmdArgs,
   // rpaths. This is currently true from this place, but we need to be
   // careful if this function is ever called before user's rpaths are emitted.
   if (Opts & RLO_AddRPath) {
-    assert(DarwinLibName.ends_with(".dylib") && "must be a dynamic library");
+    assert(StringRef(P).ends_with(".dylib") && "must be a dynamic library");
 
     // Add @executable_path to rpath to support having the dylib copied with
     // the executable.
     CmdArgs.push_back("-rpath");
     CmdArgs.push_back("@executable_path");
 
-    // Add the path to the resource dir to rpath to support using the dylib
-    // from the default location without copying.
+    // Add the compiler-rt library's directory to rpath to support using the
+    // dylib from the default location without copying.
     CmdArgs.push_back("-rpath");
-    CmdArgs.push_back(Args.MakeArgString(Dir));
+    CmdArgs.push_back(Args.MakeArgString(llvm::sys::path::parent_path(P)));
+  }
+}
+
+std::string MachO::getCompilerRT(const ArgList &, StringRef Component,
+                                 FileType Type) const {
+  assert(Type != ToolChain::FT_Object &&
+         "it doesn't make sense to ask for the compiler-rt library name as an "
+         "object file");
+  SmallString<64> MachOLibName = StringRef("libclang_rt");
+  // On MachO, the builtins component is not in the library name
+  if (Component != "builtins") {
+    MachOLibName += '.';
+    MachOLibName += Component;
+  }
+  MachOLibName += Type == ToolChain::FT_Shared ? "_dynamic.dylib" : ".a";
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ldionne wrote:

We only ever have `.a`s in there, so I think we should unconditionally use the `.a` extension to avoid creating confusion.

https://github.com/llvm/llvm-project/pull/98325