[driver] return immediately in addArchSpecificRPath and getArchSpecificLibPaths on AIX (llvm#134520)

`addArchSpecificRPath` should immediately return for AIX as AIX doesn't
support `rpath` option.
`getArchSpecificLibPaths` should return as well as we don't want
`-L/ArchSepcificLibPaths` sent to the linker on AIX.

Author: DanielCChen

clang/lib/Driver/ToolChains/AIX.h

@@ -98,6 +98,8 @@ class LLVM_LIBRARY_VISIBILITY AIX : public ToolChain {
     return llvm::DebuggerKind::DBX;
   }
 
+  path_list getArchSpecificLibPaths() const override { return path_list(); };
+
 protected:
   Tool *buildAssembler() const override;
   Tool *buildLinker() const override;

clang/lib/Driver/ToolChains/CommonArgs.cpp

@@ -1252,6 +1252,9 @@ void tools::addArchSpecificRPath(const ToolChain &TC, const ArgList &Args,
                     options::OPT_fno_rtlib_add_rpath, false))
     return;
 
+  if (TC.getTriple().isOSAIX()) // TODO: AIX doesn't support -rpath option.
+    return;
+
   SmallVector<std::string> CandidateRPaths(TC.getArchSpecificLibPaths());
   if (const auto CandidateRPath = TC.getStdlibPath())
     CandidateRPaths.emplace_back(*CandidateRPath);

flang/test/Driver/flang-ld-powerpc.f90

@@ -23,6 +23,7 @@
 ! AIX64-LD-PER-TARGET-DEFAULT-SAME:     "[[RESOURCE_DIR]]{{/|\\\\}}lib{{/|\\\\}}powerpc64-ibm-aix{{/|\\\\}}libflang_rt.runtime.a"
 ! AIX64-LD-PER-TARGET-DEFAULT-SAME:     "-lm"
 ! AIX64-LD-PER-TARGET-DEFAULT-SAME:     "-lpthread"
+! AIX64-LD-PER-TARGET-DEFAULT-NOT:      "-L/[[RESOURCE_DIR]]{{/|\\\\}}lib{{/|\\\\}}powerpc64-ibm-aix"
 
 
 ! Check powerpc64-ibm-aix 64-bit linking to static flang-rt by option