[clang][AIX] Fix -print-runtime-dir fallback on AIX (llvm#141439)

If the runtime path is not found (by getTargetSubDirPath()), since per
target runtime directory is enabled on AIX, we should fall back to the
target subdirectory rather than the OS subdirectory.

Author: jakeegan

clang/lib/Driver/ToolChain.cpp

@@ -933,11 +933,16 @@ ToolChain::getTargetSubDirPath(StringRef BaseDir) const {
   if (auto Path = getPathForTriple(T))
     return *Path;
 
-  if (T.isOSAIX() && T.getEnvironment() == Triple::UnknownEnvironment) {
-    // Strip unknown environment from the triple.
-    const llvm::Triple AIXTriple(
-        llvm::Triple(T.getArchName(), T.getVendorName(),
-                     llvm::Triple::getOSTypeName(T.getOS())));
+  if (T.isOSAIX()) {
+    llvm::Triple AIXTriple;
+    if (T.getEnvironment() == Triple::UnknownEnvironment) {
+      // Strip unknown environment and the OS version from the triple.
+      AIXTriple = llvm::Triple(T.getArchName(), T.getVendorName(),
+                               llvm::Triple::getOSTypeName(T.getOS()));
+    } else {
+      // Strip the OS version from the triple.
+      AIXTriple = getTripleWithoutOSVersion();
+    }
     if (auto Path = getPathForTriple(AIXTriple))
       return *Path;
   }
@@ -987,14 +992,6 @@ std::optional<std::string> ToolChain::getRuntimePath() const {
   if (Triple.isOSDarwin())
     return {};
 
-  // For AIX, get the triple without the OS version.
-  if (Triple.isOSAIX()) {
-    const llvm::Triple &TripleWithoutVersion = getTripleWithoutOSVersion();
-    llvm::sys::path::append(P, TripleWithoutVersion.str());
-    if (getVFS().exists(P))
-      return std::string(P);
-    return {};
-  }
   llvm::sys::path::append(P, Triple.str());
   return std::string(P);
 }

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

@@ -1,13 +1,5 @@
 // Test output of -print-runtime-dir on AIX
 
-// RUN: %clang -print-runtime-dir --target=powerpc-ibm-aix \
-// RUN:        -resource-dir=%S/Inputs/resource_dir \
-// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR %s
-
-// RUN: %clang -print-runtime-dir --target=powerpc64-ibm-aix \
-// RUN:        -resource-dir=%S/Inputs/resource_dir \
-// RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR %s
-
 // RUN: %clang -print-runtime-dir --target=powerpc-ibm-aix \
 // RUN:        -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir\
 // RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR32-PER-TARGET %s
@@ -24,7 +16,6 @@
 // RUN:        -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:      | FileCheck --check-prefix=PRINT-RUNTIME-DIR64-UNKNOWN-ENV %s 
 
-// PRINT-RUNTIME-DIR: lib{{/|\\}}aix{{$}}
 // PRINT-RUNTIME-DIR32-PER-TARGET: lib{{/|\\}}powerpc-ibm-aix{{$}}
 // PRINT-RUNTIME-DIR64-PER-TARGET: lib{{/|\\}}powerpc64-ibm-aix{{$}}
 // PRINT-RUNTIME-DIR32-UNKNOWN-ENV: lib{{/|\\}}powerpc-ibm-aix