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llvm-project/clang/lib/CodeGen/CGHLSLRuntime.cpp
Justin Bogner 99ed882a2e
[HLSL] Wrap offset info into a dedicated type. NFC (#167396) 
Rather than using a nullable SmallVector, use a wrapper class for offset
info. This simplifies places that need to handle whether or not there's
any offset information.
2025-11-11 12:03:52 -08:00

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//===----- CGHLSLRuntime.cpp - Interface to HLSL Runtimes -----------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This provides an abstract class for HLSL code generation. Concrete
// subclasses of this implement code generation for specific HLSL
// runtime libraries.
//
//===----------------------------------------------------------------------===//
#include "CGHLSLRuntime.h"
#include "Address.h"
#include "CGDebugInfo.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attrs.inc"
#include "clang/AST/Decl.h"
#include "clang/AST/HLSLResource.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/Type.h"
#include "clang/Basic/TargetOptions.h"
#include "clang/Frontend/FrontendDiagnostic.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Frontend/HLSL/RootSignatureMetadata.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Alignment.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormatVariadic.h"
#include <cstdint>
#include <optional>
using namespace clang;
using namespace CodeGen;
using namespace clang::hlsl;
using namespace llvm;
using llvm::hlsl::CBufferRowSizeInBytes;
namespace {
void addDxilValVersion(StringRef ValVersionStr, llvm::Module &M) {
// The validation of ValVersionStr is done at HLSLToolChain::TranslateArgs.
// Assume ValVersionStr is legal here.
VersionTuple Version;
if (Version.tryParse(ValVersionStr) || Version.getBuild() ||
Version.getSubminor() || !Version.getMinor()) {
return;
}
uint64_t Major = Version.getMajor();
uint64_t Minor = *Version.getMinor();
auto &Ctx = M.getContext();
IRBuilder<> B(M.getContext());
MDNode *Val = MDNode::get(Ctx, {ConstantAsMetadata::get(B.getInt32(Major)),
ConstantAsMetadata::get(B.getInt32(Minor))});
StringRef DXILValKey = "dx.valver";
auto *DXILValMD = M.getOrInsertNamedMetadata(DXILValKey);
DXILValMD->addOperand(Val);
}
void addRootSignatureMD(llvm::dxbc::RootSignatureVersion RootSigVer,
ArrayRef<llvm::hlsl::rootsig::RootElement> Elements,
llvm::Function *Fn, llvm::Module &M) {
auto &Ctx = M.getContext();
llvm::hlsl::rootsig::MetadataBuilder RSBuilder(Ctx, Elements);
MDNode *RootSignature = RSBuilder.BuildRootSignature();
ConstantAsMetadata *Version = ConstantAsMetadata::get(ConstantInt::get(
llvm::Type::getInt32Ty(Ctx), llvm::to_underlying(RootSigVer)));
ValueAsMetadata *EntryFunc = Fn ? ValueAsMetadata::get(Fn) : nullptr;
MDNode *MDVals = MDNode::get(Ctx, {EntryFunc, RootSignature, Version});
StringRef RootSignatureValKey = "dx.rootsignatures";
auto *RootSignatureValMD = M.getOrInsertNamedMetadata(RootSignatureValKey);
RootSignatureValMD->addOperand(MDVals);
}
// Find array variable declaration from nested array subscript AST nodes
static const ValueDecl *getArrayDecl(const ArraySubscriptExpr *ASE) {
const Expr *E = nullptr;
while (ASE != nullptr) {
E = ASE->getBase()->IgnoreImpCasts();
if (!E)
return nullptr;
ASE = dyn_cast<ArraySubscriptExpr>(E);
}
if (const DeclRefExpr *DRE = dyn_cast_or_null<DeclRefExpr>(E))
return DRE->getDecl();
return nullptr;
}
// Get the total size of the array, or -1 if the array is unbounded.
static int getTotalArraySize(ASTContext &AST, const clang::Type *Ty) {
Ty = Ty->getUnqualifiedDesugaredType();
assert(Ty->isArrayType() && "expected array type");
if (Ty->isIncompleteArrayType())
return -1;
return AST.getConstantArrayElementCount(cast<ConstantArrayType>(Ty));
}
static Value *buildNameForResource(llvm::StringRef BaseName,
CodeGenModule &CGM) {
llvm::SmallString<64> GlobalName = {BaseName, ".str"};
return CGM.GetAddrOfConstantCString(BaseName.str(), GlobalName.c_str())
.getPointer();
}
static CXXMethodDecl *lookupMethod(CXXRecordDecl *Record, StringRef Name,
StorageClass SC = SC_None) {
for (auto *Method : Record->methods()) {
if (Method->getStorageClass() == SC && Method->getName() == Name)
return Method;
}
return nullptr;
}
static CXXMethodDecl *lookupResourceInitMethodAndSetupArgs(
CodeGenModule &CGM, CXXRecordDecl *ResourceDecl, llvm::Value *Range,
llvm::Value *Index, StringRef Name, ResourceBindingAttrs &Binding,
CallArgList &Args) {
assert(Binding.hasBinding() && "at least one binding attribute expected");
ASTContext &AST = CGM.getContext();
CXXMethodDecl *CreateMethod = nullptr;
Value *NameStr = buildNameForResource(Name, CGM);
Value *Space = llvm::ConstantInt::get(CGM.IntTy, Binding.getSpace());
if (Binding.isExplicit()) {
// explicit binding
auto *RegSlot = llvm::ConstantInt::get(CGM.IntTy, Binding.getSlot());
Args.add(RValue::get(RegSlot), AST.UnsignedIntTy);
const char *Name = Binding.hasCounterImplicitOrderID()
? "__createFromBindingWithImplicitCounter"
: "__createFromBinding";
CreateMethod = lookupMethod(ResourceDecl, Name, SC_Static);
} else {
// implicit binding
auto *OrderID =
llvm::ConstantInt::get(CGM.IntTy, Binding.getImplicitOrderID());
Args.add(RValue::get(OrderID), AST.UnsignedIntTy);
const char *Name = Binding.hasCounterImplicitOrderID()
? "__createFromImplicitBindingWithImplicitCounter"
: "__createFromImplicitBinding";
CreateMethod = lookupMethod(ResourceDecl, Name, SC_Static);
}
Args.add(RValue::get(Space), AST.UnsignedIntTy);
Args.add(RValue::get(Range), AST.IntTy);
Args.add(RValue::get(Index), AST.UnsignedIntTy);
Args.add(RValue::get(NameStr), AST.getPointerType(AST.CharTy.withConst()));
if (Binding.hasCounterImplicitOrderID()) {
uint32_t CounterBinding = Binding.getCounterImplicitOrderID();
auto *CounterOrderID = llvm::ConstantInt::get(CGM.IntTy, CounterBinding);
Args.add(RValue::get(CounterOrderID), AST.UnsignedIntTy);
}
return CreateMethod;
}
static void callResourceInitMethod(CodeGenFunction &CGF,
CXXMethodDecl *CreateMethod,
CallArgList &Args, Address ReturnAddress) {
llvm::Constant *CalleeFn = CGF.CGM.GetAddrOfFunction(CreateMethod);
const FunctionProtoType *Proto =
CreateMethod->getType()->getAs<FunctionProtoType>();
const CGFunctionInfo &FnInfo =
CGF.CGM.getTypes().arrangeFreeFunctionCall(Args, Proto, false);
ReturnValueSlot ReturnValue(ReturnAddress, false);
CGCallee Callee(CGCalleeInfo(Proto), CalleeFn);
CGF.EmitCall(FnInfo, Callee, ReturnValue, Args, nullptr);
}
// Initializes local resource array variable. For multi-dimensional arrays it
// calls itself recursively to initialize its sub-arrays. The Index used in the
// resource constructor calls will begin at StartIndex and will be incremented
// for each array element. The last used resource Index is returned to the
// caller. If the function returns std::nullopt, it indicates an error.
static std::optional<llvm::Value *> initializeLocalResourceArray(
CodeGenFunction &CGF, CXXRecordDecl *ResourceDecl,
const ConstantArrayType *ArrayTy, AggValueSlot &ValueSlot,
llvm::Value *Range, llvm::Value *StartIndex, StringRef ResourceName,
ResourceBindingAttrs &Binding, ArrayRef<llvm::Value *> PrevGEPIndices,
SourceLocation ArraySubsExprLoc) {
ASTContext &AST = CGF.getContext();
llvm::IntegerType *IntTy = CGF.CGM.IntTy;
llvm::Value *Index = StartIndex;
llvm::Value *One = llvm::ConstantInt::get(IntTy, 1);
const uint64_t ArraySize = ArrayTy->getSExtSize();
QualType ElemType = ArrayTy->getElementType();
Address TmpArrayAddr = ValueSlot.getAddress();
// Add additional index to the getelementptr call indices.
// This index will be updated for each array element in the loops below.
SmallVector<llvm::Value *> GEPIndices(PrevGEPIndices);
GEPIndices.push_back(llvm::ConstantInt::get(IntTy, 0));
// For array of arrays, recursively initialize the sub-arrays.
if (ElemType->isArrayType()) {
const ConstantArrayType *SubArrayTy = cast<ConstantArrayType>(ElemType);
for (uint64_t I = 0; I < ArraySize; I++) {
if (I > 0) {
Index = CGF.Builder.CreateAdd(Index, One);
GEPIndices.back() = llvm::ConstantInt::get(IntTy, I);
}
std::optional<llvm::Value *> MaybeIndex = initializeLocalResourceArray(
CGF, ResourceDecl, SubArrayTy, ValueSlot, Range, Index, ResourceName,
Binding, GEPIndices, ArraySubsExprLoc);
if (!MaybeIndex)
return std::nullopt;
Index = *MaybeIndex;
}
return Index;
}
// For array of resources, initialize each resource in the array.
llvm::Type *Ty = CGF.ConvertTypeForMem(ElemType);
CharUnits ElemSize = AST.getTypeSizeInChars(ElemType);
CharUnits Align =
TmpArrayAddr.getAlignment().alignmentOfArrayElement(ElemSize);
for (uint64_t I = 0; I < ArraySize; I++) {
if (I > 0) {
Index = CGF.Builder.CreateAdd(Index, One);
GEPIndices.back() = llvm::ConstantInt::get(IntTy, I);
}
Address ReturnAddress =
CGF.Builder.CreateGEP(TmpArrayAddr, GEPIndices, Ty, Align);
CallArgList Args;
CXXMethodDecl *CreateMethod = lookupResourceInitMethodAndSetupArgs(
CGF.CGM, ResourceDecl, Range, Index, ResourceName, Binding, Args);
if (!CreateMethod)
// This can happen if someone creates an array of structs that looks like
// an HLSL resource record array but it does not have the required static
// create method. No binding will be generated for it.
return std::nullopt;
callResourceInitMethod(CGF, CreateMethod, Args, ReturnAddress);
}
return Index;
}
} // namespace
llvm::Type *
CGHLSLRuntime::convertHLSLSpecificType(const Type *T,
const CGHLSLOffsetInfo &OffsetInfo) {
assert(T->isHLSLSpecificType() && "Not an HLSL specific type!");
// Check if the target has a specific translation for this type first.
if (llvm::Type *TargetTy =
CGM.getTargetCodeGenInfo().getHLSLType(CGM, T, OffsetInfo))
return TargetTy;
llvm_unreachable("Generic handling of HLSL types is not supported.");
}
llvm::Triple::ArchType CGHLSLRuntime::getArch() {
return CGM.getTarget().getTriple().getArch();
}
// Emits constant global variables for buffer constants declarations
// and creates metadata linking the constant globals with the buffer global.
void CGHLSLRuntime::emitBufferGlobalsAndMetadata(const HLSLBufferDecl *BufDecl,
llvm::GlobalVariable *BufGV) {
LLVMContext &Ctx = CGM.getLLVMContext();
// get the layout struct from constant buffer target type
llvm::Type *BufType = BufGV->getValueType();
llvm::Type *BufLayoutType =
cast<llvm::TargetExtType>(BufType)->getTypeParameter(0);
llvm::StructType *LayoutStruct = cast<llvm::StructType>(
cast<llvm::TargetExtType>(BufLayoutType)->getTypeParameter(0));
// Start metadata list associating the buffer global variable with its
// constatns
SmallVector<llvm::Metadata *> BufGlobals;
BufGlobals.push_back(ValueAsMetadata::get(BufGV));
const auto *ElemIt = LayoutStruct->element_begin();
for (Decl *D : BufDecl->buffer_decls()) {
if (isa<CXXRecordDecl, EmptyDecl>(D))
// Nothing to do for this declaration.
continue;
if (isa<FunctionDecl>(D)) {
// A function within an cbuffer is effectively a top-level function.
CGM.EmitTopLevelDecl(D);
continue;
}
VarDecl *VD = dyn_cast<VarDecl>(D);
if (!VD)
continue;
QualType VDTy = VD->getType();
if (VDTy.getAddressSpace() != LangAS::hlsl_constant) {
if (VD->getStorageClass() == SC_Static ||
VDTy.getAddressSpace() == LangAS::hlsl_groupshared ||
VDTy->isHLSLResourceRecord() || VDTy->isHLSLResourceRecordArray()) {
// Emit static and groupshared variables and resource classes inside
// cbuffer as regular globals
CGM.EmitGlobal(VD);
} else {
// Anything else that is not in the hlsl_constant address space must be
// an empty struct or a zero-sized array and can be ignored
assert(BufDecl->getASTContext().getTypeSize(VDTy) == 0 &&
"constant buffer decl with non-zero sized type outside of "
"hlsl_constant address space");
}
continue;
}
assert(ElemIt != LayoutStruct->element_end() &&
"number of elements in layout struct does not match");
llvm::Type *LayoutType = *ElemIt++;
// FIXME: handle resources inside user defined structs
// (llvm/wg-hlsl#175)
// create global variable for the constant and to metadata list
GlobalVariable *ElemGV =
cast<GlobalVariable>(CGM.GetAddrOfGlobalVar(VD, LayoutType));
BufGlobals.push_back(ValueAsMetadata::get(ElemGV));
}
assert(ElemIt == LayoutStruct->element_end() &&
"number of elements in layout struct does not match");
// add buffer metadata to the module
CGM.getModule()
.getOrInsertNamedMetadata("hlsl.cbs")
->addOperand(MDNode::get(Ctx, BufGlobals));
}
// Creates resource handle type for the HLSL buffer declaration
static const clang::HLSLAttributedResourceType *
createBufferHandleType(const HLSLBufferDecl *BufDecl) {
ASTContext &AST = BufDecl->getASTContext();
QualType QT = AST.getHLSLAttributedResourceType(
AST.HLSLResourceTy, AST.getCanonicalTagType(BufDecl->getLayoutStruct()),
HLSLAttributedResourceType::Attributes(ResourceClass::CBuffer));
return cast<HLSLAttributedResourceType>(QT.getTypePtr());
}
CGHLSLOffsetInfo CGHLSLOffsetInfo::fromDecl(const HLSLBufferDecl &BufDecl) {
CGHLSLOffsetInfo Result;
// If we don't have packoffset info, just return an empty result.
if (!BufDecl.hasValidPackoffset())
return Result;
for (Decl *D : BufDecl.buffer_decls()) {
if (isa<CXXRecordDecl, EmptyDecl>(D) || isa<FunctionDecl>(D)) {
continue;
}
VarDecl *VD = dyn_cast<VarDecl>(D);
if (!VD || VD->getType().getAddressSpace() != LangAS::hlsl_constant)
continue;
if (!VD->hasAttrs()) {
Result.Offsets.push_back(Unspecified);
continue;
}
uint32_t Offset = Unspecified;
for (auto *Attr : VD->getAttrs()) {
if (auto *POA = dyn_cast<HLSLPackOffsetAttr>(Attr)) {
Offset = POA->getOffsetInBytes();
break;
}
auto *RBA = dyn_cast<HLSLResourceBindingAttr>(Attr);
if (RBA &&
RBA->getRegisterType() == HLSLResourceBindingAttr::RegisterType::C) {
Offset = RBA->getSlotNumber() * CBufferRowSizeInBytes;
break;
}
}
Result.Offsets.push_back(Offset);
}
return Result;
}
// Codegen for HLSLBufferDecl
void CGHLSLRuntime::addBuffer(const HLSLBufferDecl *BufDecl) {
assert(BufDecl->isCBuffer() && "tbuffer codegen is not supported yet");
// create resource handle type for the buffer
const clang::HLSLAttributedResourceType *ResHandleTy =
createBufferHandleType(BufDecl);
// empty constant buffer is ignored
if (ResHandleTy->getContainedType()->getAsCXXRecordDecl()->isEmpty())
return;
// create global variable for the constant buffer
CGHLSLOffsetInfo OffsetInfo = CGHLSLOffsetInfo::fromDecl(*BufDecl);
llvm::TargetExtType *TargetTy = cast<llvm::TargetExtType>(
convertHLSLSpecificType(ResHandleTy, OffsetInfo));
llvm::GlobalVariable *BufGV = new GlobalVariable(
TargetTy, /*isConstant*/ false,
GlobalValue::LinkageTypes::ExternalLinkage, PoisonValue::get(TargetTy),
llvm::formatv("{0}{1}", BufDecl->getName(),
BufDecl->isCBuffer() ? ".cb" : ".tb"),
GlobalValue::NotThreadLocal);
CGM.getModule().insertGlobalVariable(BufGV);
// Add globals for constant buffer elements and create metadata nodes
emitBufferGlobalsAndMetadata(BufDecl, BufGV);
// Initialize cbuffer from binding (implicit or explicit)
initializeBufferFromBinding(BufDecl, BufGV);
}
void CGHLSLRuntime::addRootSignature(
const HLSLRootSignatureDecl *SignatureDecl) {
llvm::Module &M = CGM.getModule();
Triple T(M.getTargetTriple());
// Generated later with the function decl if not targeting root signature
if (T.getEnvironment() != Triple::EnvironmentType::RootSignature)
return;
addRootSignatureMD(SignatureDecl->getVersion(),
SignatureDecl->getRootElements(), nullptr, M);
}
llvm::TargetExtType *
CGHLSLRuntime::getHLSLBufferLayoutType(const RecordType *StructType) {
const auto Entry = LayoutTypes.find(StructType);
if (Entry != LayoutTypes.end())
return Entry->getSecond();
return nullptr;
}
void CGHLSLRuntime::addHLSLBufferLayoutType(const RecordType *StructType,
llvm::TargetExtType *LayoutTy) {
assert(getHLSLBufferLayoutType(StructType) == nullptr &&
"layout type for this struct already exist");
LayoutTypes[StructType] = LayoutTy;
}
void CGHLSLRuntime::finishCodeGen() {
auto &TargetOpts = CGM.getTarget().getTargetOpts();
auto &CodeGenOpts = CGM.getCodeGenOpts();
auto &LangOpts = CGM.getLangOpts();
llvm::Module &M = CGM.getModule();
Triple T(M.getTargetTriple());
if (T.getArch() == Triple::ArchType::dxil)
addDxilValVersion(TargetOpts.DxilValidatorVersion, M);
if (CodeGenOpts.ResMayAlias)
M.setModuleFlag(llvm::Module::ModFlagBehavior::Error, "dx.resmayalias", 1);
// NativeHalfType corresponds to the -fnative-half-type clang option which is
// aliased by clang-dxc's -enable-16bit-types option. This option is used to
// set the UseNativeLowPrecision DXIL module flag in the DirectX backend
if (LangOpts.NativeHalfType)
M.setModuleFlag(llvm::Module::ModFlagBehavior::Error, "dx.nativelowprec",
1);
generateGlobalCtorDtorCalls();
}
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,
llvm::Triple::getEnvironmentTypeName(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);
}
if (HLSLWaveSizeAttr *WaveSizeAttr = FD->getAttr<HLSLWaveSizeAttr>()) {
const StringRef WaveSizeKindStr = "hlsl.wavesize";
std::string WaveSizeStr =
formatv("{0},{1},{2}", WaveSizeAttr->getMin(), WaveSizeAttr->getMax(),
WaveSizeAttr->getPreferred());
Fn->addFnAttr(WaveSizeKindStr, WaveSizeStr);
}
// HLSL entry functions are materialized for module functions with
// HLSLShaderAttr attribute. SetLLVMFunctionAttributesForDefinition called
// later in the compiler-flow for such module functions is not aware of and
// hence not able to set attributes of the newly materialized entry functions.
// So, set attributes of entry function here, as appropriate.
if (CGM.getCodeGenOpts().OptimizationLevel == 0)
Fn->addFnAttr(llvm::Attribute::OptimizeNone);
Fn->addFnAttr(llvm::Attribute::NoInline);
if (CGM.getLangOpts().HLSLSpvEnableMaximalReconvergence) {
Fn->addFnAttr("enable-maximal-reconvergence", "true");
}
}
static Value *buildVectorInput(IRBuilder<> &B, Function *F, llvm::Type *Ty) {
if (const auto *VT = dyn_cast<FixedVectorType>(Ty)) {
Value *Result = PoisonValue::get(Ty);
for (unsigned I = 0; I < VT->getNumElements(); ++I) {
Value *Elt = B.CreateCall(F, {B.getInt32(I)});
Result = B.CreateInsertElement(Result, Elt, I);
}
return Result;
}
return B.CreateCall(F, {B.getInt32(0)});
}
static void addSPIRVBuiltinDecoration(llvm::GlobalVariable *GV,
unsigned BuiltIn) {
LLVMContext &Ctx = GV->getContext();
IRBuilder<> B(GV->getContext());
MDNode *Operands = MDNode::get(
Ctx,
{ConstantAsMetadata::get(B.getInt32(/* Spirv::Decoration::BuiltIn */ 11)),
ConstantAsMetadata::get(B.getInt32(BuiltIn))});
MDNode *Decoration = MDNode::get(Ctx, {Operands});
GV->addMetadata("spirv.Decorations", *Decoration);
}
static void addLocationDecoration(llvm::GlobalVariable *GV, unsigned Location) {
LLVMContext &Ctx = GV->getContext();
IRBuilder<> B(GV->getContext());
MDNode *Operands =
MDNode::get(Ctx, {ConstantAsMetadata::get(B.getInt32(/* Location */ 30)),
ConstantAsMetadata::get(B.getInt32(Location))});
MDNode *Decoration = MDNode::get(Ctx, {Operands});
GV->addMetadata("spirv.Decorations", *Decoration);
}
static llvm::Value *createSPIRVBuiltinLoad(IRBuilder<> &B, llvm::Module &M,
llvm::Type *Ty, const Twine &Name,
unsigned BuiltInID) {
auto *GV = new llvm::GlobalVariable(
M, Ty, /* isConstant= */ true, llvm::GlobalValue::ExternalLinkage,
/* Initializer= */ nullptr, Name, /* insertBefore= */ nullptr,
llvm::GlobalVariable::GeneralDynamicTLSModel,
/* AddressSpace */ 7, /* isExternallyInitialized= */ true);
addSPIRVBuiltinDecoration(GV, BuiltInID);
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
return B.CreateLoad(Ty, GV);
}
static llvm::Value *createSPIRVLocationLoad(IRBuilder<> &B, llvm::Module &M,
llvm::Type *Ty, unsigned Location,
StringRef Name) {
auto *GV = new llvm::GlobalVariable(
M, Ty, /* isConstant= */ true, llvm::GlobalValue::ExternalLinkage,
/* Initializer= */ nullptr, /* Name= */ Name, /* insertBefore= */ nullptr,
llvm::GlobalVariable::GeneralDynamicTLSModel,
/* AddressSpace */ 7, /* isExternallyInitialized= */ true);
GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
addLocationDecoration(GV, Location);
return B.CreateLoad(Ty, GV);
}
llvm::Value *
CGHLSLRuntime::emitSPIRVUserSemanticLoad(llvm::IRBuilder<> &B, llvm::Type *Type,
HLSLSemanticAttr *Semantic,
std::optional<unsigned> Index) {
Twine BaseName = Twine(Semantic->getAttrName()->getName());
Twine VariableName = BaseName.concat(Twine(Index.value_or(0)));
unsigned Location = SPIRVLastAssignedInputSemanticLocation;
// DXC completely ignores the semantic/index pair. Location are assigned from
// the first semantic to the last.
llvm::ArrayType *AT = dyn_cast<llvm::ArrayType>(Type);
unsigned ElementCount = AT ? AT->getNumElements() : 1;
SPIRVLastAssignedInputSemanticLocation += ElementCount;
return createSPIRVLocationLoad(B, CGM.getModule(), Type, Location,
VariableName.str());
}
llvm::Value *
CGHLSLRuntime::emitDXILUserSemanticLoad(llvm::IRBuilder<> &B, llvm::Type *Type,
HLSLSemanticAttr *Semantic,
std::optional<unsigned> Index) {
Twine BaseName = Twine(Semantic->getAttrName()->getName());
Twine VariableName = BaseName.concat(Twine(Index.value_or(0)));
// DXIL packing rules etc shall be handled here.
// FIXME: generate proper sigpoint, index, col, row values.
// FIXME: also DXIL loads vectors element by element.
SmallVector<Value *> Args{B.getInt32(4), B.getInt32(0), B.getInt32(0),
B.getInt8(0),
llvm::PoisonValue::get(B.getInt32Ty())};
llvm::Intrinsic::ID IntrinsicID = llvm::Intrinsic::dx_load_input;
llvm::Value *Value = B.CreateIntrinsic(/*ReturnType=*/Type, IntrinsicID, Args,
nullptr, VariableName);
return Value;
}
llvm::Value *CGHLSLRuntime::emitUserSemanticLoad(
IRBuilder<> &B, llvm::Type *Type, const clang::DeclaratorDecl *Decl,
HLSLSemanticAttr *Semantic, std::optional<unsigned> Index) {
if (CGM.getTarget().getTriple().isSPIRV())
return emitSPIRVUserSemanticLoad(B, Type, Semantic, Index);
if (CGM.getTarget().getTriple().isDXIL())
return emitDXILUserSemanticLoad(B, Type, Semantic, Index);
llvm_unreachable("Unsupported target for user-semantic load.");
}
llvm::Value *CGHLSLRuntime::emitSystemSemanticLoad(
IRBuilder<> &B, llvm::Type *Type, const clang::DeclaratorDecl *Decl,
Attr *Semantic, std::optional<unsigned> Index) {
if (isa<HLSLSV_GroupIndexAttr>(Semantic)) {
llvm::Function *GroupIndex =
CGM.getIntrinsic(getFlattenedThreadIdInGroupIntrinsic());
return B.CreateCall(FunctionCallee(GroupIndex));
}
if (isa<HLSLSV_DispatchThreadIDAttr>(Semantic)) {
llvm::Intrinsic::ID IntrinID = getThreadIdIntrinsic();
llvm::Function *ThreadIDIntrinsic =
llvm::Intrinsic::isOverloaded(IntrinID)
? CGM.getIntrinsic(IntrinID, {CGM.Int32Ty})
: CGM.getIntrinsic(IntrinID);
return buildVectorInput(B, ThreadIDIntrinsic, Type);
}
if (isa<HLSLSV_GroupThreadIDAttr>(Semantic)) {
llvm::Intrinsic::ID IntrinID = getGroupThreadIdIntrinsic();
llvm::Function *GroupThreadIDIntrinsic =
llvm::Intrinsic::isOverloaded(IntrinID)
? CGM.getIntrinsic(IntrinID, {CGM.Int32Ty})
: CGM.getIntrinsic(IntrinID);
return buildVectorInput(B, GroupThreadIDIntrinsic, Type);
}
if (isa<HLSLSV_GroupIDAttr>(Semantic)) {
llvm::Intrinsic::ID IntrinID = getGroupIdIntrinsic();
llvm::Function *GroupIDIntrinsic =
llvm::Intrinsic::isOverloaded(IntrinID)
? CGM.getIntrinsic(IntrinID, {CGM.Int32Ty})
: CGM.getIntrinsic(IntrinID);
return buildVectorInput(B, GroupIDIntrinsic, Type);
}
if (HLSLSV_PositionAttr *S = dyn_cast<HLSLSV_PositionAttr>(Semantic)) {
if (CGM.getTriple().getEnvironment() == Triple::EnvironmentType::Pixel)
return createSPIRVBuiltinLoad(B, CGM.getModule(), Type,
S->getAttrName()->getName(),
/* BuiltIn::FragCoord */ 15);
}
llvm_unreachable("non-handled system semantic. FIXME.");
}
llvm::Value *
CGHLSLRuntime::handleScalarSemanticLoad(IRBuilder<> &B, const FunctionDecl *FD,
llvm::Type *Type,
const clang::DeclaratorDecl *Decl) {
HLSLSemanticAttr *Semantic = nullptr;
for (HLSLSemanticAttr *Item : FD->specific_attrs<HLSLSemanticAttr>()) {
if (Item->getTargetDecl() == Decl) {
Semantic = Item;
break;
}
}
// Sema must create one attribute per scalar field.
assert(Semantic);
std::optional<unsigned> Index = std::nullopt;
if (Semantic->isSemanticIndexExplicit())
Index = Semantic->getSemanticIndex();
if (isa<HLSLUserSemanticAttr>(Semantic))
return emitUserSemanticLoad(B, Type, Decl, Semantic, Index);
return emitSystemSemanticLoad(B, Type, Decl, Semantic, Index);
}
llvm::Value *
CGHLSLRuntime::handleStructSemanticLoad(IRBuilder<> &B, const FunctionDecl *FD,
llvm::Type *Type,
const clang::DeclaratorDecl *Decl) {
const llvm::StructType *ST = cast<StructType>(Type);
const clang::RecordDecl *RD = Decl->getType()->getAsRecordDecl();
assert(std::distance(RD->field_begin(), RD->field_end()) ==
ST->getNumElements());
llvm::Value *Aggregate = llvm::PoisonValue::get(Type);
auto FieldDecl = RD->field_begin();
for (unsigned I = 0; I < ST->getNumElements(); ++I) {
llvm::Value *ChildValue =
handleSemanticLoad(B, FD, ST->getElementType(I), *FieldDecl);
assert(ChildValue);
Aggregate = B.CreateInsertValue(Aggregate, ChildValue, I);
++FieldDecl;
}
return Aggregate;
}
llvm::Value *
CGHLSLRuntime::handleSemanticLoad(IRBuilder<> &B, const FunctionDecl *FD,
llvm::Type *Type,
const clang::DeclaratorDecl *Decl) {
if (Type->isStructTy())
return handleStructSemanticLoad(B, FD, Type, Decl);
return handleScalarSemanticLoad(B, FD, Type, Decl);
}
void CGHLSLRuntime::emitEntryFunction(const FunctionDecl *FD,
llvm::Function *Fn) {
llvm::Module &M = CGM.getModule();
llvm::LLVMContext &Ctx = M.getContext();
auto *EntryTy = llvm::FunctionType::get(llvm::Type::getVoidTy(Ctx), false);
Function *EntryFn =
Function::Create(EntryTy, Function::ExternalLinkage, FD->getName(), &M);
// Copy function attributes over, we have no argument or return attributes
// that can be valid on the real entry.
AttributeList NewAttrs = AttributeList::get(Ctx, AttributeList::FunctionIndex,
Fn->getAttributes().getFnAttrs());
EntryFn->setAttributes(NewAttrs);
setHLSLEntryAttributes(FD, EntryFn);
// Set the called function as internal linkage.
Fn->setLinkage(GlobalValue::InternalLinkage);
BasicBlock *BB = BasicBlock::Create(Ctx, "entry", EntryFn);
IRBuilder<> B(BB);
llvm::SmallVector<Value *> Args;
SmallVector<OperandBundleDef, 1> OB;
if (CGM.shouldEmitConvergenceTokens()) {
assert(EntryFn->isConvergent());
llvm::Value *I =
B.CreateIntrinsic(llvm::Intrinsic::experimental_convergence_entry, {});
llvm::Value *bundleArgs[] = {I};
OB.emplace_back("convergencectrl", bundleArgs);
}
// FIXME: support struct parameters where semantics are on members.
// See: https://github.com/llvm/llvm-project/issues/57874
unsigned SRetOffset = 0;
for (const auto &Param : Fn->args()) {
if (Param.hasStructRetAttr()) {
// FIXME: support output.
// See: https://github.com/llvm/llvm-project/issues/57874
SRetOffset = 1;
Args.emplace_back(PoisonValue::get(Param.getType()));
continue;
}
const ParmVarDecl *PD = FD->getParamDecl(Param.getArgNo() - SRetOffset);
llvm::Value *SemanticValue = nullptr;
if ([[maybe_unused]] HLSLParamModifierAttr *MA =
PD->getAttr<HLSLParamModifierAttr>()) {
llvm_unreachable("Not handled yet");
} else {
llvm::Type *ParamType =
Param.hasByValAttr() ? Param.getParamByValType() : Param.getType();
SemanticValue = handleSemanticLoad(B, FD, ParamType, PD);
if (!SemanticValue)
return;
if (Param.hasByValAttr()) {
llvm::Value *Var = B.CreateAlloca(Param.getParamByValType());
B.CreateStore(SemanticValue, Var);
SemanticValue = Var;
}
}
assert(SemanticValue);
Args.push_back(SemanticValue);
}
CallInst *CI = B.CreateCall(FunctionCallee(Fn), Args, OB);
CI->setCallingConv(Fn->getCallingConv());
// FIXME: Handle codegen for return type semantics.
// See: https://github.com/llvm/llvm-project/issues/57875
B.CreateRetVoid();
// Add and identify root signature to function, if applicable
for (const Attr *Attr : FD->getAttrs()) {
if (const auto *RSAttr = dyn_cast<RootSignatureAttr>(Attr)) {
auto *RSDecl = RSAttr->getSignatureDecl();
addRootSignatureMD(RSDecl->getVersion(), RSDecl->getRootElements(),
EntryFn, M);
}
}
}
static void gatherFunctions(SmallVectorImpl<Function *> &Fns, llvm::Module &M,
bool CtorOrDtor) {
const auto *GV =
M.getNamedGlobal(CtorOrDtor ? "llvm.global_ctors" : "llvm.global_dtors");
if (!GV)
return;
const auto *CA = dyn_cast<ConstantArray>(GV->getInitializer());
if (!CA)
return;
// The global_ctor array elements are a struct [Priority, Fn *, COMDat].
// HLSL neither supports priorities or COMDat values, so we will check those
// in an assert but not handle them.
for (const auto &Ctor : CA->operands()) {
if (isa<ConstantAggregateZero>(Ctor))
continue;
ConstantStruct *CS = cast<ConstantStruct>(Ctor);
assert(cast<ConstantInt>(CS->getOperand(0))->getValue() == 65535 &&
"HLSL doesn't support setting priority for global ctors.");
assert(isa<ConstantPointerNull>(CS->getOperand(2)) &&
"HLSL doesn't support COMDat for global ctors.");
Fns.push_back(cast<Function>(CS->getOperand(1)));
}
}
void CGHLSLRuntime::generateGlobalCtorDtorCalls() {
llvm::Module &M = CGM.getModule();
SmallVector<Function *> CtorFns;
SmallVector<Function *> DtorFns;
gatherFunctions(CtorFns, M, true);
gatherFunctions(DtorFns, M, false);
// Insert a call to the global constructor at the beginning of the entry block
// to externally exported functions. This is a bit of a hack, but HLSL allows
// global constructors, but doesn't support driver initialization of globals.
for (auto &F : M.functions()) {
if (!F.hasFnAttribute("hlsl.shader"))
continue;
auto *Token = getConvergenceToken(F.getEntryBlock());
Instruction *IP = &*F.getEntryBlock().begin();
SmallVector<OperandBundleDef, 1> OB;
if (Token) {
llvm::Value *bundleArgs[] = {Token};
OB.emplace_back("convergencectrl", bundleArgs);
IP = Token->getNextNode();
}
IRBuilder<> B(IP);
for (auto *Fn : CtorFns) {
auto CI = B.CreateCall(FunctionCallee(Fn), {}, OB);
CI->setCallingConv(Fn->getCallingConv());
}
// Insert global dtors before the terminator of the last instruction
B.SetInsertPoint(F.back().getTerminator());
for (auto *Fn : DtorFns) {
auto CI = B.CreateCall(FunctionCallee(Fn), {}, OB);
CI->setCallingConv(Fn->getCallingConv());
}
}
// No need to keep global ctors/dtors for non-lib profile after call to
// ctors/dtors added for entry.
Triple T(M.getTargetTriple());
if (T.getEnvironment() != Triple::EnvironmentType::Library) {
if (auto *GV = M.getNamedGlobal("llvm.global_ctors"))
GV->eraseFromParent();
if (auto *GV = M.getNamedGlobal("llvm.global_dtors"))
GV->eraseFromParent();
}
}
static void initializeBuffer(CodeGenModule &CGM, llvm::GlobalVariable *GV,
Intrinsic::ID IntrID,
ArrayRef<llvm::Value *> Args) {
LLVMContext &Ctx = CGM.getLLVMContext();
llvm::Function *InitResFunc = llvm::Function::Create(
llvm::FunctionType::get(CGM.VoidTy, false),
llvm::GlobalValue::InternalLinkage,
("_init_buffer_" + GV->getName()).str(), CGM.getModule());
InitResFunc->addFnAttr(llvm::Attribute::AlwaysInline);
llvm::BasicBlock *EntryBB =
llvm::BasicBlock::Create(Ctx, "entry", InitResFunc);
CGBuilderTy Builder(CGM, Ctx);
const DataLayout &DL = CGM.getModule().getDataLayout();
Builder.SetInsertPoint(EntryBB);
// Make sure the global variable is buffer resource handle
llvm::Type *HandleTy = GV->getValueType();
assert(HandleTy->isTargetExtTy() && "unexpected type of the buffer global");
llvm::Value *CreateHandle = Builder.CreateIntrinsic(
/*ReturnType=*/HandleTy, IntrID, Args, nullptr,
Twine(GV->getName()).concat("_h"));
llvm::Value *HandleRef = Builder.CreateStructGEP(GV->getValueType(), GV, 0);
Builder.CreateAlignedStore(CreateHandle, HandleRef,
HandleRef->getPointerAlignment(DL));
Builder.CreateRetVoid();
CGM.AddCXXGlobalInit(InitResFunc);
}
void CGHLSLRuntime::initializeBufferFromBinding(const HLSLBufferDecl *BufDecl,
llvm::GlobalVariable *GV) {
ResourceBindingAttrs Binding(BufDecl);
assert(Binding.hasBinding() &&
"cbuffer/tbuffer should always have resource binding attribute");
auto *Index = llvm::ConstantInt::get(CGM.IntTy, 0);
auto *RangeSize = llvm::ConstantInt::get(CGM.IntTy, 1);
auto *Space = llvm::ConstantInt::get(CGM.IntTy, Binding.getSpace());
Value *Name = buildNameForResource(BufDecl->getName(), CGM);
// buffer with explicit binding
if (Binding.isExplicit()) {
llvm::Intrinsic::ID IntrinsicID =
CGM.getHLSLRuntime().getCreateHandleFromBindingIntrinsic();
auto *RegSlot = llvm::ConstantInt::get(CGM.IntTy, Binding.getSlot());
SmallVector<Value *> Args{Space, RegSlot, RangeSize, Index, Name};
initializeBuffer(CGM, GV, IntrinsicID, Args);
} else {
// buffer with implicit binding
llvm::Intrinsic::ID IntrinsicID =
CGM.getHLSLRuntime().getCreateHandleFromImplicitBindingIntrinsic();
auto *OrderID =
llvm::ConstantInt::get(CGM.IntTy, Binding.getImplicitOrderID());
SmallVector<Value *> Args{OrderID, Space, RangeSize, Index, Name};
initializeBuffer(CGM, GV, IntrinsicID, Args);
}
}
void CGHLSLRuntime::handleGlobalVarDefinition(const VarDecl *VD,
llvm::GlobalVariable *GV) {
if (auto Attr = VD->getAttr<HLSLVkExtBuiltinInputAttr>())
addSPIRVBuiltinDecoration(GV, Attr->getBuiltIn());
}
llvm::Instruction *CGHLSLRuntime::getConvergenceToken(BasicBlock &BB) {
if (!CGM.shouldEmitConvergenceTokens())
return nullptr;
auto E = BB.end();
for (auto I = BB.begin(); I != E; ++I) {
auto *II = dyn_cast<llvm::IntrinsicInst>(&*I);
if (II && llvm::isConvergenceControlIntrinsic(II->getIntrinsicID())) {
return II;
}
}
llvm_unreachable("Convergence token should have been emitted.");
return nullptr;
}
class OpaqueValueVisitor : public RecursiveASTVisitor<OpaqueValueVisitor> {
public:
llvm::SmallVector<OpaqueValueExpr *, 8> OVEs;
llvm::SmallPtrSet<OpaqueValueExpr *, 8> Visited;
OpaqueValueVisitor() {}
bool VisitHLSLOutArgExpr(HLSLOutArgExpr *) {
// These need to be bound in CodeGenFunction::EmitHLSLOutArgLValues
// or CodeGenFunction::EmitHLSLOutArgExpr. If they are part of this
// traversal, the temporary containing the copy out will not have
// been created yet.
return false;
}
bool VisitOpaqueValueExpr(OpaqueValueExpr *E) {
// Traverse the source expression first.
if (E->getSourceExpr())
TraverseStmt(E->getSourceExpr());
// Then add this OVE if we haven't seen it before.
if (Visited.insert(E).second)
OVEs.push_back(E);
return true;
}
};
void CGHLSLRuntime::emitInitListOpaqueValues(CodeGenFunction &CGF,
InitListExpr *E) {
typedef CodeGenFunction::OpaqueValueMappingData OpaqueValueMappingData;
OpaqueValueVisitor Visitor;
Visitor.TraverseStmt(E);
for (auto *OVE : Visitor.OVEs) {
if (CGF.isOpaqueValueEmitted(OVE))
continue;
if (OpaqueValueMappingData::shouldBindAsLValue(OVE)) {
LValue LV = CGF.EmitLValue(OVE->getSourceExpr());
OpaqueValueMappingData::bind(CGF, OVE, LV);
} else {
RValue RV = CGF.EmitAnyExpr(OVE->getSourceExpr());
OpaqueValueMappingData::bind(CGF, OVE, RV);
}
}
}
std::optional<LValue> CGHLSLRuntime::emitResourceArraySubscriptExpr(
const ArraySubscriptExpr *ArraySubsExpr, CodeGenFunction &CGF) {
assert((ArraySubsExpr->getType()->isHLSLResourceRecord() ||
ArraySubsExpr->getType()->isHLSLResourceRecordArray()) &&
"expected resource array subscript expression");
// Let clang codegen handle local resource array subscripts,
// or when the subscript references on opaque expression (as part of
// ArrayInitLoopExpr AST node).
const VarDecl *ArrayDecl =
dyn_cast_or_null<VarDecl>(getArrayDecl(ArraySubsExpr));
if (!ArrayDecl || !ArrayDecl->hasGlobalStorage())
return std::nullopt;
// get the resource array type
ASTContext &AST = ArrayDecl->getASTContext();
const Type *ResArrayTy = ArrayDecl->getType().getTypePtr();
assert(ResArrayTy->isHLSLResourceRecordArray() &&
"expected array of resource classes");
// Iterate through all nested array subscript expressions to calculate
// the index in the flattened resource array (if this is a multi-
// dimensional array). The index is calculated as a sum of all indices
// multiplied by the total size of the array at that level.
Value *Index = nullptr;
const ArraySubscriptExpr *ASE = ArraySubsExpr;
while (ASE != nullptr) {
Value *SubIndex = CGF.EmitScalarExpr(ASE->getIdx());
if (const auto *ArrayTy =
dyn_cast<ConstantArrayType>(ASE->getType().getTypePtr())) {
Value *Multiplier = llvm::ConstantInt::get(
CGM.IntTy, AST.getConstantArrayElementCount(ArrayTy));
SubIndex = CGF.Builder.CreateMul(SubIndex, Multiplier);
}
Index = Index ? CGF.Builder.CreateAdd(Index, SubIndex) : SubIndex;
ASE = dyn_cast<ArraySubscriptExpr>(ASE->getBase()->IgnoreParenImpCasts());
}
// Find binding info for the resource array. For implicit binding
// an HLSLResourceBindingAttr should have been added by SemaHLSL.
ResourceBindingAttrs Binding(ArrayDecl);
assert((Binding.hasBinding()) &&
"resource array must have a binding attribute");
// Find the individual resource type.
QualType ResultTy = ArraySubsExpr->getType();
QualType ResourceTy =
ResultTy->isArrayType() ? AST.getBaseElementType(ResultTy) : ResultTy;
// Create a temporary variable for the result, which is either going
// to be a single resource instance or a local array of resources (we need to
// return an LValue).
RawAddress TmpVar = CGF.CreateMemTemp(ResultTy);
if (CGF.EmitLifetimeStart(TmpVar.getPointer()))
CGF.pushFullExprCleanup<CodeGenFunction::CallLifetimeEnd>(
NormalEHLifetimeMarker, TmpVar);
AggValueSlot ValueSlot = AggValueSlot::forAddr(
TmpVar, Qualifiers(), AggValueSlot::IsDestructed_t(true),
AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsAliased_t(false),
AggValueSlot::DoesNotOverlap);
// Calculate total array size (= range size).
llvm::Value *Range =
llvm::ConstantInt::get(CGM.IntTy, getTotalArraySize(AST, ResArrayTy));
// If the result of the subscript operation is a single resource, call the
// constructor.
if (ResultTy == ResourceTy) {
CallArgList Args;
CXXMethodDecl *CreateMethod = lookupResourceInitMethodAndSetupArgs(
CGF.CGM, ResourceTy->getAsCXXRecordDecl(), Range, Index,
ArrayDecl->getName(), Binding, Args);
if (!CreateMethod)
// This can happen if someone creates an array of structs that looks like
// an HLSL resource record array but it does not have the required static
// create method. No binding will be generated for it.
return std::nullopt;
callResourceInitMethod(CGF, CreateMethod, Args, ValueSlot.getAddress());
} else {
// The result of the subscript operation is a local resource array which
// needs to be initialized.
const ConstantArrayType *ArrayTy =
cast<ConstantArrayType>(ResultTy.getTypePtr());
std::optional<llvm::Value *> EndIndex = initializeLocalResourceArray(
CGF, ResourceTy->getAsCXXRecordDecl(), ArrayTy, ValueSlot, Range, Index,
ArrayDecl->getName(), Binding, {llvm::ConstantInt::get(CGM.IntTy, 0)},
ArraySubsExpr->getExprLoc());
if (!EndIndex)
return std::nullopt;
}
return CGF.MakeAddrLValue(TmpVar, ResultTy, AlignmentSource::Decl);
}
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