[Driver] Fix `ToolChain::getCompilerRTPath()` to return the correct path on Apple platforms.

[delcypher]

Summary

When the target triple was an Apple platform ToolChain::getOSLibName()
(called by getCompilerRTPath()) would return the full OS name
including the version number (e.g. darwin20.3.0). This is not correct
because the library directory for all Apple platforms is darwin.

This in turn caused

• -print-runtime-dir to return a non-existant path.
• -print-file-name=<any compiler-rt library> to return the filename instead of the full path to the library.

Two regression tests are included.

rdar://77417317

[arphaman]

clang/lib/Driver/ToolChain.cpp

404

Should this also apply to llvm::Triple::MacOSX , iOS, and other Darwin OSes?

[delcypher]

• Support other Apple target triples.

[delcypher]

clang/lib/Driver/ToolChain.cpp

404

Good catch. I've fixed this.

[arphaman]

LGTM, the only suggestion I have is below.

clang/lib/Driver/ToolChain.cpp

405

It might be cleaner to do a check for isOSDarwin here, as that will help with any other Darwin platforms that we need to support.

[delcypher]

Use isOSDarwin() instead of explicitly checking Darwin OS enum values.

[delcypher]

clang/lib/Driver/ToolChain.cpp

405

@arphaman That seems like a good idea. I didn't know this API existed. I'll try to switch to that.

clang/lib/Driver/ToolChain.cpp

static StringRef getArchNameForCompilerRTLib(const ToolChain &TC,
   // For historic reasons, Android library is using i686 instead of i386.
   if (TC.getArch() == llvm::Triple::x86 && Triple.isAndroid())
     return "i686";
 
   return llvm::Triple::getArchTypeName(TC.getArch());
 }
 
 StringRef ToolChain::getOSLibName() const {
+  if (Triple.isOSDarwin())
+    return "darwin";
+
   switch (Triple.getOS()) {
   case llvm::Triple::FreeBSD:
     return "freebsd";
   case llvm::Triple::NetBSD:
     return "netbsd";
   case llvm::Triple::OpenBSD:
     return "openbsd";
   case llvm::Triple::Solaris:
     return "sunos";
   case llvm::Triple::AIX:
     return "aix";
   default:
     return getOS();
   }
 }
 
 std::string ToolChain::getCompilerRTPath() const {
   SmallString<128> Path(getDriver().ResourceDir);
   if (Triple.isOSUnknown()) {
     llvm::sys::path::append(Path, "lib");
   } else {

clang/test/Driver/darwin-print-file-name.c

+// Regression test. Previously Clang just returned the library name instead
+// of the full path.
+
+// RUN: %clang -print-file-name=libclang_rt.osx.a --target=x86_64-apple-darwin20.3.0 \
+// RUN:        -resource-dir=%S/Inputs/resource_dir \
+// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR %s
+
+// RUN: %clang -print-file-name=libclang_rt.osx.a --target=x86_64-apple-macosx11.0.0 \
+// RUN:        -resource-dir=%S/Inputs/resource_dir \
+// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR %s
+
+// PRINT-RUNTIME-DIR: lib{{/|\\}}darwin{{/|\\}}libclang_rt.osx.a
+
+// RUN: %clang -print-file-name=libclang_rt.ios.a --target=arm64-apple-ios14.0.0 \
+// RUN:        -resource-dir=%S/Inputs/resource_dir \
+// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR-IOS %s
+// PRINT-RUNTIME-DIR-IOS: lib{{/|\\}}darwin{{/|\\}}libclang_rt.ios.a
+
+// RUN: %clang -print-file-name=libclang_rt.tvos.a --target=arm64-apple-tvos14.0.0 \
+// RUN:        -resource-dir=%S/Inputs/resource_dir \
+// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR-TVOS %s
+// PRINT-RUNTIME-DIR-TVOS: lib{{/|\\}}darwin{{/|\\}}libclang_rt.tvos.a
+
+// RUN: %clang -print-file-name=libclang_rt.watchos.a --target=arm64-apple-watchos5.0.0 \
+// RUN:        -resource-dir=%S/Inputs/resource_dir \
+// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR-WATCHOS %s
+// PRINT-RUNTIME-DIR-WATCHOS: lib{{/|\\}}darwin{{/|\\}}libclang_rt.watchos.a

clang/test/Driver/darwin-print-runtime-dir.c

+// Regression test. Previously the output returned the full OS name
+// (e.g. `darwin20.3.0`) instead of just `darwin`.
+
+// RUN: %clang -print-runtime-dir --target=x86_64-apple-darwin20.3.0 \
+// RUN:        -resource-dir=%S/Inputs/resource_dir \
+// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR %s
+
+// RUN: %clang -print-runtime-dir --target=x86_64-apple-macosx11.0.0 \
+// RUN:        -resource-dir=%S/Inputs/resource_dir \
+// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR %s
+
+// RUN: %clang -print-runtime-dir --target=arm64-apple-ios14.0.0 \
+// RUN:        -resource-dir=%S/Inputs/resource_dir \
+// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR %s
+
+// RUN: %clang -print-runtime-dir --target=arm64-apple-tvos14.0.0 \
+// RUN:        -resource-dir=%S/Inputs/resource_dir \
+// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR %s
+
+// RUN: %clang -print-runtime-dir --target=arm64-apple-watchos5.0.0 \
+// RUN:        -resource-dir=%S/Inputs/resource_dir \
+// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR %s
+
+// PRINT-RUNTIME-DIR: lib{{/|\\}}darwin{{$}}