[HLSL] clang codeGen for HLSLNumThreadsAttr

[python3kgae]

Summary

Translate HLSLNumThreadsAttr into function attribute with name "dx.numthreads" and value format as "x,y,z".

[beanz]

clang/lib/CodeGen/CGHLSLRuntime.cpp

216

This isn't DirectX-specific, so we should name it hlsl.

[python3kgae]

Change attribute name to hlsl.numthreads

[beanz]

clang/lib/CodeGen/CGHLSLRuntime.cpp

221

You can replace this whole chunk of code with:

std::string NumThreadsStr = llvm::formatv("{0},{1},{2}", NumThreadsAttr->getX(), NumThreadsAttr->getY(), NumThreadsAttr->getZ()).str();

[python3kgae]

Use llvm::formatv.

[python3kgae]

Fix build error and merge conflict.

[python3kgae]

Rebase

[python3kgae]

Rebase

[beanz]

LGTM

clang/lib/CodeGen/CGHLSLRuntime.cpp

 
 #include "CGHLSLRuntime.h"
 #include "CodeGenModule.h"
 #include "clang/AST/Decl.h"
 #include "clang/Basic/TargetOptions.h"
 #include "llvm/IR/IntrinsicsDirectX.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/FormatVariadic.h"
 
 using namespace clang;
 using namespace CodeGen;
 using namespace hlsl;
 using namespace llvm;
 
 namespace {
 void addDxilValVersion(StringRef ValVersionStr, llvm::Module &M) {

 
 void clang::CodeGen::CGHLSLRuntime::setHLSLEntryAttributes(
     const FunctionDecl *FD, llvm::Function *Fn) {
   const auto *ShaderAttr = FD->getAttr<HLSLShaderAttr>();
   assert(ShaderAttr && "All entry functions must have a HLSLShaderAttr");
   const StringRef ShaderAttrKindStr = "hlsl.shader";
   Fn->addFnAttr(ShaderAttrKindStr,
                 ShaderAttr->ConvertShaderTypeToStr(ShaderAttr->getType()));
+  if (HLSLNumThreadsAttr *NumThreadsAttr = FD->getAttr<HLSLNumThreadsAttr>()) {
+    const StringRef NumThreadsKindStr = "hlsl.numthreads";
+    std::string NumThreadsStr =
+        formatv("{0},{1},{2}", NumThreadsAttr->getX(), NumThreadsAttr->getY(),
+                NumThreadsAttr->getZ());
+    Fn->addFnAttr(NumThreadsKindStr, NumThreadsStr);
+  }
 }
 
 llvm::Value *CGHLSLRuntime::emitInputSemantic(IRBuilder<> &B,
                                               const ParmVarDecl &D) {
   assert(D.hasAttrs() && "Entry parameter missing annotation attribute!");
   if (D.hasAttr<HLSLSV_GroupIndexAttr>()) {
     llvm::Function *DxGroupIndex =
         CGM.getIntrinsic(Intrinsic::dx_flattened_thread_id_in_group);
for (auto &F : M.functions()) {
     for (auto *Fn : CtorFns)
       B.CreateCall(FunctionCallee(Fn));
 
     // Insert global dtors before the terminator of the last instruction
     B.SetInsertPoint(F.back().getTerminator());
     for (auto *Fn : DtorFns)
       B.CreateCall(FunctionCallee(Fn));
   }
 }

clang/test/CodeGenHLSL/entry.hlsl

 // RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -x hlsl -triple \
 // RUN:   dxil-pc-shadermodel6.3-compute %s -hlsl-entry foo \
 // RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s
 
 // Make sure not mangle entry.
 // CHECK:define void @foo()
-// Make sure add function attribute.
+// Make sure add function attribute and numthreads attribute.
+// CHECK:"hlsl.numthreads"="16,8,1"
 // CHECK:"hlsl.shader"="compute"
-[numthreads(1,1,1)]
+[numthreads(16,8,1)]
 void foo() {
 
 }