[NFC] [HLSL] Move common metadata to LLVMFrontend

[beanz]

Summary

This change pulls some code from the DirectX backend into a new
LLVMFrontendHLSL library to share utility data structures between the
HLSL code generation in Clang and the backend in LLVM.

This is a small refactoring as a first start to get code into the
right structure and get the library built and dependencies correct.

Fixes #58000 (https://github.com/llvm/llvm-project/issues/58000)

[python3kgae]

llvm/include/llvm/Frontend/HLSL/HLSLResource.h

36

Could we save things like shape and component type instead of a StringRef which needs to be parsed later?

[tschuett]

The OpenMP frontend is mainly an IRBuilder. It is a different layering than for HLSL. Are there plans for an HLSL(IR)Builder?

[beanz]

In D135110#3832728, @tschuett wrote:

The OpenMP frontend is mainly an IRBuilder. It is a different layering than for HLSL. Are there plans for an HLSL(IR)Builder?

HLSL and OpenMP are different in a lot of ways. HLSL's code generation is fairly consistent with C/C++. There will be some areas where we have special IR generation mechanics (like around copy-in/copy-out function parameters), which I expect we'll create some sort of reusable API for. I'm unsure if we have enough unique cases to make a full builder worth it.

Similar to OpenCL we also have a lot of metadata that needs to get passed from the frontend to the backend. That's really where this patch is starting. Having shared utilities for reading and writing metadata.

llvm/include/llvm/Frontend/HLSL/HLSLResource.h

36

This change is an NFC refactoring to move code around and start sharing between the front-end and backend. We have a separate issue tracking extending the frontend attribute support to capture more metadata (https://github.com/llvm/llvm-project/issues/57991). That will be a separate change.

[beanz]

Rebasing

[python3kgae]

llvm/lib/Target/DirectX/DXILResource.h

46

Could we move ResourceBase::Kinds to Frontend/HLSL/HLSLResource.h so we can share it between clang and llvm?

[beanz]

llvm/lib/Target/DirectX/DXILResource.h

46

Within reason, we can move any code that makes sense to share. We should do that in changes where the moved code will be used rather than making this change larger.

[mstorsjo]

I don't quite know why, but it seems like this new library breaks tests of llvm-config; if I start out with an empty build directory and run ninja check-llvm (or ninja llvm-test-depends), then this library doesn't get built, and llvm-config prints llvm-config: error: missing: $HOME/code/llvm-project/llvm/build/lib/libLLVMFrontendHLSL.a - and that breaks tools/llvm-config/booleans.test and tools/llvm-config/system-libs.test.

[mariusz-sikora-at-amd]

In D135110#3859844, @mstorsjo wrote:

I don't quite know why, but it seems like this new library breaks tests of llvm-config; if I start out with an empty build directory and run ninja check-llvm (or ninja llvm-test-depends), then this library doesn't get built, and llvm-config prints llvm-config: error: missing: $HOME/code/llvm-project/llvm/build/lib/libLLVMFrontendHLSL.a - and that breaks tools/llvm-config/booleans.test and tools/llvm-config/system-libs.test.

I see the same issue.

[dstuttard]

I think that the reason we don't see the same failure for e.g. OpenACC is that there's a unittest/Frontend that requires OpenACC - if I comment out that subdir in the unittests/CMakeLists.txt it fails llvm-config test in the same way for OpenACC. Similarly, if I add FrontendHLSL as an LLVM_LINK_COMPONENT in unittests/Frontend/CMakeLists.txt (even though it isn't), the static lib is generated and llvm-lit llvm-config test passes.

[beanz]

I think I have a fix for this and I'll get it up today.

[beanz]

The llvm-config test issue should be resolved in rGa4b010034f57

clang/lib/CodeGen/CGHLSLRuntime.cpp

 //
 //===----------------------------------------------------------------------===//
 
 #include "CGHLSLRuntime.h"
 #include "CGDebugInfo.h"
 #include "CodeGenModule.h"
 #include "clang/AST/Decl.h"
 #include "clang/Basic/TargetOptions.h"
+#include "llvm/Frontend/HLSL/HLSLResource.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;
void CGHLSLRuntime::annotateHLSLResource(const VarDecl *D, GlobalVariable *GV) {
   }
 
   assert(ResourceMD != nullptr &&
          "ResourceMD must have been set by the switch above.");
 
   auto &Ctx = CGM.getModule().getContext();
   IRBuilder<> B(Ctx);
   QualType QT(Ty, 0);
-  ResourceMD->addOperand(MDNode::get(
-      Ctx, {ValueAsMetadata::get(GV), MDString::get(Ctx, QT.getAsString()),
-            ConstantAsMetadata::get(B.getInt32(Counter))}));
+  llvm::hlsl::FrontendResource Res(GV, QT.getAsString(), Counter);
+  ResourceMD->addOperand(Res.getMetadata());
 }
 
 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,

clang/lib/CodeGen/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Analysis
   BitReader
   BitWriter
   Core
   Coroutines
   Coverage
   Demangle
   Extensions
+  FrontendHLSL
   FrontendOpenMP
   IPO
   IRReader
   AggressiveInstCombine
   InstCombine
   Instrumentation
   LTO
   Linker

llvm/include/llvm/Frontend/HLSL/HLSLResource.h

+//===- HLSLResource.h - HLSL Resource helper objects ----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file This file contains helper objects for working with HLSL Resources.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FRONTEND_HLSL_HLSLRESOURCE_H
+#define LLVM_FRONTEND_HLSL_HLSLRESOURCE_H
+
+#include "llvm/IR/Metadata.h"
+
+namespace llvm {
+class Module;
+class GlobalVariable;
+
+namespace hlsl {
+
+class FrontendResource {
+  MDNode *Entry;
+
+public:
+  FrontendResource(MDNode *E) : Entry(E) {
+    assert(Entry->getNumOperands() == 3 && "Unexpected metadata shape");
+  }
+
+  FrontendResource(GlobalVariable *GV, StringRef TypeStr, uint32_t Counter);
+
+  GlobalVariable *getGlobalVariable();
+  StringRef getSourceType();
+  Constant *getID();
+
+  MDNode *getMetadata() { return Entry; }
+};
+} // namespace hlsl
+} // namespace llvm
+
+#endif // LLVM_FRONTEND_HLSL_HLSLRESOURCE_H

llvm/lib/Frontend/CMakeLists.txt

+add_subdirectory(HLSL)
 add_subdirectory(OpenACC)
 add_subdirectory(OpenMP)

llvm/lib/Frontend/HLSL/CMakeLists.txt

+add_llvm_component_library(LLVMFrontendHLSL
+  HLSLResource.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${LLVM_MAIN_INCLUDE_DIR}/llvm/Frontend
+  ${LLVM_MAIN_INCLUDE_DIR}/llvm/Frontend/HLSL
+
+  DEPENDS
+  intrinsics_gen
+
+  LINK_COMPONENTS
+  Core
+  Support
+  )

llvm/lib/Frontend/HLSL/HLSLResource.cpp

+//===- HLSLResource.cpp - HLSL Resource helper objects --------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file This file contains helper objects for working with HLSL Resources.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Frontend/HLSL/HLSLResource.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/Module.h"
+
+using namespace llvm;
+using namespace llvm::hlsl;
+
+GlobalVariable *FrontendResource::getGlobalVariable() {
+  return cast<GlobalVariable>(
+      cast<ConstantAsMetadata>(Entry->getOperand(0))->getValue());
+}
+
+StringRef FrontendResource::getSourceType() {
+  return cast<MDString>(Entry->getOperand(1))->getString();
+}
+
+Constant *FrontendResource::getID() {
+  return cast<ConstantAsMetadata>(Entry->getOperand(2))->getValue();
+}
+
+FrontendResource::FrontendResource(GlobalVariable *GV, StringRef TypeStr,
+                                   uint32_t Counter) {
+  auto &Ctx = GV->getContext();
+  IRBuilder<> B(Ctx);
+  Entry =
+      MDNode::get(Ctx, {ValueAsMetadata::get(GV), MDString::get(Ctx, TypeStr),
+                        ConstantAsMetadata::get(B.getInt32(Counter))});
+}

llvm/lib/Target/DirectX/CMakeLists.txt

add_llvm_target(DirectXCodeGen
 
   LINK_COMPONENTS
   AsmPrinter
   Core
   SelectionDAG
   Support
   DirectXInfo
   DXILBitWriter
+  FrontendHLSL
 
   ADD_TO_COMPONENT
   DirectX
 )
 
 add_subdirectory(MCTargetDesc)
 add_subdirectory(TargetInfo)
 add_subdirectory(DXILWriter)

llvm/lib/Target/DirectX/DXILResource.h

 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_TARGET_DIRECTX_DXILRESOURCE_H
 #define LLVM_TARGET_DIRECTX_DXILRESOURCE_H
 
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Frontend/HLSL/HLSLResource.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/Support/Compiler.h"
 #include <cstdint>
 
 namespace llvm {
 class Module;
 class GlobalVariable;
 
 namespace dxil {
 
-// FIXME: Ultimately this class and some of these utilities should be moved into
-// a new LLVMFrontendHLSL library so that they can be reused in Clang.
-// See issue https://github.com/llvm/llvm-project/issues/58000.
-class FrontendResource {
-  MDNode *Entry;
-
-public:
-  FrontendResource(MDNode *E) : Entry(E) {
-    assert(Entry->getNumOperands() == 3 && "Unexpected metadata shape");
-  }
-
-  GlobalVariable *getGlobalVariable();
-  StringRef getSourceType();
-  Constant *getID();
-};
-
 class ResourceBase {
 protected:
   uint32_t ID;
   GlobalVariable *GV;
   StringRef Name;
   uint32_t Space;
   uint32_t LowerBound;
   uint32_t RangeSize;
-  ResourceBase(uint32_t I, FrontendResource R);
+  ResourceBase(uint32_t I, hlsl::FrontendResource R);
 
   void write(LLVMContext &Ctx, MutableArrayRef<Metadata *> Entries) const;
 
   void print(raw_ostream &O, StringRef IDPrefix, StringRef BindingPrefix) const;
 
   // The value ordering of this enumeration is part of the DXIL ABI. Elements
   // can only be added to the end, and not removed.
   enum class Kinds : uint32_t {
     Invalid = 0,
     Texture1D,
     Texture2D,
     Texture2DMS,
     Texture3D,
     TextureCube,
     Texture1DArray,
     Texture2DArray,
class UAVResource : public ResourceBase {
   bool GloballyCoherent;
   bool HasCounter;
   bool IsROV;
   ResourceBase::ExtendedProperties ExtProps;
 
   void parseSourceType(StringRef S);
 
 public:
-  UAVResource(uint32_t I, FrontendResource R);
+  UAVResource(uint32_t I, hlsl::FrontendResource R);
 
   MDNode *write() const;
   void print(raw_ostream &O) const;
 };
 
 // FIXME: Fully computing the resource structures requires analyzing the IR
 // because some flags are set based on what operations are performed on the
 // resource. This partial patch handles some of the leg work, but not all of it.

llvm/lib/Target/DirectX/DXILResource.cpp

 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Format.h"
 
 using namespace llvm;
 using namespace llvm::dxil;
-
-GlobalVariable *FrontendResource::getGlobalVariable() {
-  return cast<GlobalVariable>(
-      cast<ConstantAsMetadata>(Entry->getOperand(0))->getValue());
-}
-
-StringRef FrontendResource::getSourceType() {
-  return cast<MDString>(Entry->getOperand(1))->getString();
-}
-
-Constant *FrontendResource::getID() {
-  return cast<ConstantAsMetadata>(Entry->getOperand(2))->getValue();
-}
+using namespace llvm::hlsl;
 
 void Resources::collectUAVs(Module &M) {
   NamedMDNode *Entry = M.getNamedMetadata("hlsl.uavs");
   if (!Entry || Entry->getNumOperands() == 0)
     return;
 
   uint32_t Counter = 0;
   for (auto *UAV : Entry->operands()) {