[HLSL] Create HLSL legalization passes

The semantics of HLSL require passes some passes to be run that will
modify the llvm-ir created by clang to match what is expected by the
backend.

In this PR, wewe move the DXILFinalizeLinkage to be run for all backend.
The pass is also renamed to HLSLFinalizeLinkage. A pass of the global opt
pass is run afterwards.

Fixes #122767.

Author: s-perron

clang/lib/CodeGen/BackendUtil.cpp

@@ -56,8 +56,10 @@
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/TargetParser/SubtargetFeature.h"
 #include "llvm/TargetParser/Triple.h"
+#include "llvm/Transforms/HLSL/HLSLFinalizeLinkage.h"
 #include "llvm/Transforms/HipStdPar/HipStdPar.h"
 #include "llvm/Transforms/IPO/EmbedBitcodePass.h"
+#include "llvm/Transforms/IPO/GlobalOpt.h"
 #include "llvm/Transforms/IPO/LowerTypeTests.h"
 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
 #include "llvm/Transforms/InstCombine/InstCombine.h"
@@ -1097,6 +1099,12 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
   if (CodeGenOpts.LinkBitcodePostopt)
     MPM.addPass(LinkInModulesPass(BC));
 
+  if (LangOpts.HLSL) {
+    // HLSL legalization passes
+    MPM.addPass(HLSLFinalizeLinkage());
+    MPM.addPass(GlobalOptPass());
+  }
+
   // Add a verifier pass if requested. We don't have to do this if the action
   // requires code generation because there will already be a verifier pass in
   // the code-generation pipeline.

clang/lib/CodeGen/CMakeLists.txt

@@ -14,6 +14,7 @@ set(LLVM_LINK_COMPONENTS
   FrontendOpenMP
   FrontendOffloading
   HIPStdPar
+  HLSL
   IPO
   IRPrinter
   IRReader

clang/test/CodeGenHLSL/inline-functions.hlsl

@@ -61,7 +61,7 @@ unsigned RemoveDupes(unsigned Buf[MAX], unsigned size) {
 }
 
 
-RWBuffer<unsigned> Indices;
+RWBuffer<unsigned> Indices : register(u0);
 
 // The mangled version of main only remains without inlining
 // because it has internal linkage from the start

llvm/lib/Target/DirectX/CMakeLists.txt

@@ -21,7 +21,6 @@ add_llvm_target(DirectXCodeGen
   DirectXTargetTransformInfo.cpp
   DXContainerGlobals.cpp
   DXILDataScalarization.cpp
-  DXILFinalizeLinkage.cpp
   DXILFlattenArrays.cpp
   DXILIntrinsicExpansion.cpp
   DXILOpBuilder.cpp

llvm/lib/Target/DirectX/DXILFinalizeLinkage.cpp

@@ -61,7 +61,6 @@ extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeDirectXTarget() {
   initializeDXILTranslateMetadataLegacyPass(*PR);
   initializeDXILResourceMDWrapperPass(*PR);
   initializeShaderFlagsAnalysisWrapperPass(*PR);
-  initializeDXILFinalizeLinkageLegacyPass(*PR);
 }
 
 class DXILTargetObjectFile : public TargetLoweringObjectFile {
@@ -91,7 +90,6 @@ class DirectXPassConfig : public TargetPassConfig {
 
   FunctionPass *createTargetRegisterAllocator(bool) override { return nullptr; }
   void addCodeGenPrepare() override {
-    addPass(createDXILFinalizeLinkageLegacyPass());
     addPass(createDXILIntrinsicExpansionLegacyPass());
     addPass(createDXILDataScalarizationLegacyPass());
     addPass(createDXILFlattenArraysLegacyPass());

llvm/lib/Target/DirectX/DXILFinalizeLinkage.h

@@ -9,3 +9,4 @@ add_subdirectory(ObjCARC)
 add_subdirectory(Coroutines)
 add_subdirectory(CFGuard)
 add_subdirectory(HipStdPar)
+add_subdirectory(HLSL)

llvm/lib/Target/DirectX/DirectXTargetMachine.cpp

@@ -0,0 +1,18 @@
+add_llvm_component_library(LLVMHlsl
+  HLSLFinalizeLinkage.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${LLVM_MAIN_INCLUDE_DIR}/llvm/Transforms/HLSL
+
+  DEPENDS
+  intrinsics_gen
+  LLVMAnalysis
+
+  COMPONENT_NAME
+  HLSL
+
+  LINK_COMPONENTS
+  Analysis
+  Core
+  Support
+  TransformUtils)