[Clang][AMDGPU][Driver] Add avail-extern-gv-in-addrspace-to-local option when ThinTLO is enabled

On AMDGPU, we need an extra argument `-avail-extern-gv-in-addrspace-to-local=3`
to privatize LDS global variables when ThinLTO is enabled.

Author: shiltian

clang/lib/Driver/ToolChains/Clang.cpp

@@ -9186,6 +9186,9 @@ void LinkerWrapper::ConstructJob(Compilation &C, const JobAction &JA,
           CmdArgs.push_back(
               Args.MakeArgString("--device-linker=" + TC->getTripleString() +
                                  "=-plugin-opt=-avail-extern-to-local"));
+          CmdArgs.push_back(Args.MakeArgString(
+              "--device-linker=" + TC->getTripleString() +
+              "=-plugin-opt=-avail-extern-gv-in-addrspace-to-local=3"));
           if (Kind == Action::OFK_OpenMP) {
             CmdArgs.push_back(
                 Args.MakeArgString("--device-linker=" + TC->getTripleString() +

clang/lib/Driver/ToolChains/HIPAMD.cpp

@@ -102,6 +102,8 @@ void AMDGCN::Linker::constructLldCommand(Compilation &C, const JobAction &JA,
   if (IsThinLTO) {
     LldArgs.push_back(Args.MakeArgString("-plugin-opt=-force-import-all"));
     LldArgs.push_back(Args.MakeArgString("-plugin-opt=-avail-extern-to-local"));
+    LldArgs.push_back(Args.MakeArgString(
+        "-plugin-opt=-avail-extern-gv-in-addrspace-to-local=3"));
   }
 
   for (const Arg *A : Args.filtered(options::OPT_mllvm)) {

clang/test/Driver/hip-thinlto.hip

@@ -3,6 +3,7 @@
 // CHECK: -plugin-opt=thinlto
 // CHECK-SAME: -plugin-opt=-force-import-all
 // CHECK-SAME: -plugin-opt=-avail-extern-to-local
+// CHECK-SAME: -plugin-opt=-avail-extern-gv-in-addrspace-to-local=3
 int main(int, char *[]) {
   return 0;
 }

clang/test/Driver/openmp-offload-gpu.c

@@ -388,6 +388,7 @@
 // THINLTO-GFX906: --device-compiler=amdgcn-amd-amdhsa=-flto=thin
 // THINLTO-GFX906-SAME: --device-linker=amdgcn-amd-amdhsa=-plugin-opt=-force-import-all
 // THINLTO-GFX906-SAME: --device-linker=amdgcn-amd-amdhsa=-plugin-opt=-avail-extern-to-local
+// THINLTO-GFX906-SAME: --device-linker=amdgcn-amd-amdhsa=-plugin-opt=-avail-extern-gv-in-addrspace-to-local=3
 // THINLTO-GFX906-SAME: --device-linker=amdgcn-amd-amdhsa=-plugin-opt=-amdgpu-internalize-symbols
 //
 // RUN:   %clang -### --target=x86_64-unknown-linux-gnu -fopenmp=libomp \