[Driver] Make -G TargetSpecific

so that we report `unsupported option '-G' for target ...` on
unsupported targets (most targets).
This error is tested by one target in aix-err-options.c.

Follow-up to D89897 and D90063.

Author: MaskRay

clang/include/clang/Driver/Options.td

@@ -723,7 +723,7 @@ def E : Flag<["-"], "E">, Flags<[NoXarchOption,CC1Option, FlangOption, FC1Option
     HelpText<"Only run the preprocessor">;
 def F : JoinedOrSeparate<["-"], "F">, Flags<[RenderJoined,CC1Option]>,
     HelpText<"Add directory to framework include search path">;
-def G : JoinedOrSeparate<["-"], "G">, Flags<[NoXarchOption]>, Group<m_Group>,
+def G : JoinedOrSeparate<["-"], "G">, Flags<[NoXarchOption,TargetSpecific]>, Group<m_Group>,
     MetaVarName<"<size>">, HelpText<"Put objects of at most <size> bytes "
     "into small data section (MIPS / Hexagon)">;
 def G_EQ : Joined<["-"], "G=">, Flags<[NoXarchOption]>, Group<m_Group>, Alias<G>;

clang/lib/Driver/Driver.cpp

@@ -4739,13 +4739,8 @@ void Driver::BuildJobs(Compilation &C) const {
   }
 
   const llvm::Triple &RawTriple = C.getDefaultToolChain().getTriple();
-  if (RawTriple.isOSAIX()) {
-    if (Arg *A = C.getArgs().getLastArg(options::OPT_G))
-      Diag(diag::err_drv_unsupported_opt_for_target)
-          << A->getSpelling() << RawTriple.str();
-    if (LTOMode == LTOK_Thin)
-      Diag(diag::err_drv_clang_unsupported) << "thinLTO on AIX";
-  }
+  if (RawTriple.isOSAIX() && LTOMode == LTOK_Thin)
+    Diag(diag::err_drv_clang_unsupported) << "thinLTO on AIX";
 
   // Collect the list of architectures.
   llvm::StringSet<> ArchNames;

clang/lib/Driver/ToolChains/AIX.cpp

@@ -112,6 +112,11 @@ void aix::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   if (!(IsArch32Bit || IsArch64Bit))
     llvm_unreachable("Unsupported bit width value.");
 
+  if (Arg *A = C.getArgs().getLastArg(options::OPT_G)) {
+    D.Diag(diag::err_drv_unsupported_opt_for_target)
+        << A->getSpelling() << D.getTargetTriple();
+  }
+
   // Force static linking when "-static" is present.
   if (Args.hasArg(options::OPT_static))
     CmdArgs.push_back("-bnso");

clang/test/Driver/aix-err-options.c

@@ -4,25 +4,18 @@
 // RUN:   FileCheck --check-prefix=CHECK32 %s
 // RUN: %clang --target=powerpc-ibm-aix-xcoff -### -c -G 0 2>&1 %s | \
 // RUN:   FileCheck --check-prefix=CHECK32 %s
-// RUN: %clang --target=powerpc-ibm-aix-xcoff -### -c \
-// RUN:     %S/Inputs/aix_ppc_tree/dummy0.s -G 0 2>&1 | \
-// RUN:   FileCheck --check-prefix=CHECK32 %s
-// RUN: %clang --target=powerpc-ibm-aix-xcoff -### -o dummy.so \
-// RUN:     %S/Inputs/aix_ppc_tree/dummy0.o -G 0 2>&1 | \
-// RUN:   FileCheck --check-prefix=CHECK32 %s
+// RUN: touch %t.s %t.o
+// RUN: %clang --target=powerpc-ibm-aix-xcoff -### -c %t.s -G 0 2>&1 | FileCheck --check-prefix=CHECK32 %s
+// RUN: %clang --target=powerpc-ibm-aix-xcoff -### -o dummy.so %t.o -G 0 2>&1 | FileCheck --check-prefix=CHECK32 %s
 
 // RUN: %clang --target=powerpc64-ibm-aix-xcoff -### -E -G 0 2>&1 %s | \
 // RUN:   FileCheck --check-prefix=CHECK64 %s
 // RUN: %clang --target=powerpc64-ibm-aix-xcoff -### -S -emit-llvm -G 0 2>&1 %s | \
 // RUN:   FileCheck --check-prefix=CHECK64 %s
 // RUN: %clang --target=powerpc64-ibm-aix-xcoff -### -c -G 0 2>&1 %s | \
 // RUN:   FileCheck --check-prefix=CHECK64 %s
-// RUN: %clang --target=powerpc64-ibm-aix-xcoff -### -c \
-// RUN:     %S/Inputs/aix_ppc_tree/dummy0.s -G 0 2>&1 | \
-// RUN:   FileCheck --check-prefix=CHECK64 %s
-// RUN: %clang --target=powerpc64-ibm-aix-xcoff -### -o dummy.so \
-// RUN:     %S/Inputs/aix_ppc_tree/dummy0.o -G 0 2>&1 | \
-// RUN:   FileCheck --check-prefix=CHECK64 %s
+// RUN: %clang --target=powerpc64-ibm-aix-xcoff -### -c %t.s -G 0 2>&1 | FileCheck --check-prefix=CHECK64 %s
+// RUN: %clang --target=powerpc64-ibm-aix-xcoff -### -o dummy.so %t.o -G 0 2>&1 | FileCheck --check-prefix=CHECK64 %s
 
 // CHECK32: error: unsupported option '-G' for target 'powerpc-ibm-aix-xcoff'
 // CHECK64: error: unsupported option '-G' for target 'powerpc64-ibm-aix-xcoff'