[AMDGPU][LTO] Assume closed world after linking

Change-Id: I7d8fa4251c80a6f815f55a0998677d18ade25b72

Author: gandhi56

clang/test/CodeGenCUDA/gpu-rdc-amdgpu-attrs.cu

@@ -0,0 +1,12 @@
+// RUN: clang -x hip -O3 -fgpu-rdc %s -mllvm -debug-only=amdgpu-attributor -o - | FileCheck %s
+
+// CHECK: Module {{.*}} is not assumed to be a closed world
+// CHECK: Module ld-temp.o is assumed to be a closed world
+
+__attribute__((device)) int foo() {
+    return 1;
+}
+
+int main() {
+    return 0;
+}

llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp

@@ -1066,6 +1066,10 @@ static bool runImpl(Module &M, AnalysisGetter &AG, TargetMachine &TM,
 
   Attributor A(Functions, InfoCache, AC);
 
+  LLVM_DEBUG(dbgs() << "Module " << M.getName() << " is "
+                    << (AC.IsClosedWorldModule ? "" : "not ")
+                    << "assumed to be a closed world\n");
+
   for (Function &F : M) {
     if (F.isIntrinsic())
       continue;

llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp

@@ -761,7 +761,8 @@ void AMDGPUTargetMachine::registerPassBuilderCallbacks(PassBuilder &PB) {
         if (EnableLowerModuleLDS)
           PM.addPass(AMDGPULowerModuleLDSPass(*this));
         if (EnableAMDGPUAttributor && Level != OptimizationLevel::O0)
-          PM.addPass(AMDGPUAttributorPass(*this));
+          PM.addPass(
+              AMDGPUAttributorPass(*this, AMDGPUAttributorOptions{true}));
       });
 
   PB.registerRegClassFilterParsingCallback(