clang 19.0.0git
CGHLSLRuntime.cpp
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1//===----- CGHLSLRuntime.cpp - Interface to HLSL Runtimes -----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This provides an abstract class for HLSL code generation. Concrete
10// subclasses of this implement code generation for specific HLSL
11// runtime libraries.
12//
13//===----------------------------------------------------------------------===//
14
15#include "CGHLSLRuntime.h"
16#include "CGDebugInfo.h"
17#include "CodeGenModule.h"
18#include "clang/AST/Decl.h"
20#include "llvm/IR/Metadata.h"
21#include "llvm/IR/Module.h"
22#include "llvm/Support/FormatVariadic.h"
23
24using namespace clang;
25using namespace CodeGen;
26using namespace clang::hlsl;
27using namespace llvm;
28
29namespace {
30
31void addDxilValVersion(StringRef ValVersionStr, llvm::Module &M) {
32 // The validation of ValVersionStr is done at HLSLToolChain::TranslateArgs.
33 // Assume ValVersionStr is legal here.
34 VersionTuple Version;
35 if (Version.tryParse(ValVersionStr) || Version.getBuild() ||
36 Version.getSubminor() || !Version.getMinor()) {
37 return;
38 }
39
40 uint64_t Major = Version.getMajor();
41 uint64_t Minor = *Version.getMinor();
42
43 auto &Ctx = M.getContext();
44 IRBuilder<> B(M.getContext());
45 MDNode *Val = MDNode::get(Ctx, {ConstantAsMetadata::get(B.getInt32(Major)),
46 ConstantAsMetadata::get(B.getInt32(Minor))});
47 StringRef DXILValKey = "dx.valver";
48 auto *DXILValMD = M.getOrInsertNamedMetadata(DXILValKey);
49 DXILValMD->addOperand(Val);
50}
51void addDisableOptimizations(llvm::Module &M) {
52 StringRef Key = "dx.disable_optimizations";
53 M.addModuleFlag(llvm::Module::ModFlagBehavior::Override, Key, 1);
54}
55// cbuffer will be translated into global variable in special address space.
56// If translate into C,
57// cbuffer A {
58// float a;
59// float b;
60// }
61// float foo() { return a + b; }
62//
63// will be translated into
64//
65// struct A {
66// float a;
67// float b;
68// } cbuffer_A __attribute__((address_space(4)));
69// float foo() { return cbuffer_A.a + cbuffer_A.b; }
70//
71// layoutBuffer will create the struct A type.
72// replaceBuffer will replace use of global variable a and b with cbuffer_A.a
73// and cbuffer_A.b.
74//
75void layoutBuffer(CGHLSLRuntime::Buffer &Buf, const DataLayout &DL) {
76 if (Buf.Constants.empty())
77 return;
78
79 std::vector<llvm::Type *> EltTys;
80 for (auto &Const : Buf.Constants) {
81 GlobalVariable *GV = Const.first;
82 Const.second = EltTys.size();
83 llvm::Type *Ty = GV->getValueType();
84 EltTys.emplace_back(Ty);
85 }
86 Buf.LayoutStruct = llvm::StructType::get(EltTys[0]->getContext(), EltTys);
87}
88
89GlobalVariable *replaceBuffer(CGHLSLRuntime::Buffer &Buf) {
90 // Create global variable for CB.
91 GlobalVariable *CBGV = new GlobalVariable(
92 Buf.LayoutStruct, /*isConstant*/ true,
93 GlobalValue::LinkageTypes::ExternalLinkage, nullptr,
94 llvm::formatv("{0}{1}", Buf.Name, Buf.IsCBuffer ? ".cb." : ".tb."),
95 GlobalValue::NotThreadLocal);
96
97 IRBuilder<> B(CBGV->getContext());
98 Value *ZeroIdx = B.getInt32(0);
99 // Replace Const use with CB use.
100 for (auto &[GV, Offset] : Buf.Constants) {
101 Value *GEP =
102 B.CreateGEP(Buf.LayoutStruct, CBGV, {ZeroIdx, B.getInt32(Offset)});
103
104 assert(Buf.LayoutStruct->getElementType(Offset) == GV->getValueType() &&
105 "constant type mismatch");
106
107 // Replace.
108 GV->replaceAllUsesWith(GEP);
109 // Erase GV.
110 GV->removeDeadConstantUsers();
111 GV->eraseFromParent();
112 }
113 return CBGV;
114}
115
116} // namespace
117
118llvm::Triple::ArchType CGHLSLRuntime::getArch() {
119 return CGM.getTarget().getTriple().getArch();
120}
121
122void CGHLSLRuntime::addConstant(VarDecl *D, Buffer &CB) {
123 if (D->getStorageClass() == SC_Static) {
124 // For static inside cbuffer, take as global static.
125 // Don't add to cbuffer.
126 CGM.EmitGlobal(D);
127 return;
128 }
129
130 auto *GV = cast<GlobalVariable>(CGM.GetAddrOfGlobalVar(D));
131 // Add debug info for constVal.
133 if (CGM.getCodeGenOpts().getDebugInfo() >=
134 codegenoptions::DebugInfoKind::LimitedDebugInfo)
135 DI->EmitGlobalVariable(cast<GlobalVariable>(GV), D);
136
137 // FIXME: support packoffset.
138 // See https://github.com/llvm/llvm-project/issues/57914.
139 uint32_t Offset = 0;
140 bool HasUserOffset = false;
141
142 unsigned LowerBound = HasUserOffset ? Offset : UINT_MAX;
143 CB.Constants.emplace_back(std::make_pair(GV, LowerBound));
144}
145
146void CGHLSLRuntime::addBufferDecls(const DeclContext *DC, Buffer &CB) {
147 for (Decl *it : DC->decls()) {
148 if (auto *ConstDecl = dyn_cast<VarDecl>(it)) {
149 addConstant(ConstDecl, CB);
150 } else if (isa<CXXRecordDecl, EmptyDecl>(it)) {
151 // Nothing to do for this declaration.
152 } else if (isa<FunctionDecl>(it)) {
153 // A function within an cbuffer is effectively a top-level function,
154 // as it only refers to globally scoped declarations.
156 }
157 }
158}
159
161 Buffers.emplace_back(Buffer(D));
162 addBufferDecls(D, Buffers.back());
163}
164
166 auto &TargetOpts = CGM.getTarget().getTargetOpts();
167 llvm::Module &M = CGM.getModule();
168 Triple T(M.getTargetTriple());
169 if (T.getArch() == Triple::ArchType::dxil)
170 addDxilValVersion(TargetOpts.DxilValidatorVersion, M);
171
173 if (CGM.getCodeGenOpts().OptimizationLevel == 0)
174 addDisableOptimizations(M);
175
176 const DataLayout &DL = M.getDataLayout();
177
178 for (auto &Buf : Buffers) {
179 layoutBuffer(Buf, DL);
180 GlobalVariable *GV = replaceBuffer(Buf);
181 M.insertGlobalVariable(GV);
182 llvm::hlsl::ResourceClass RC = Buf.IsCBuffer
183 ? llvm::hlsl::ResourceClass::CBuffer
184 : llvm::hlsl::ResourceClass::SRV;
185 llvm::hlsl::ResourceKind RK = Buf.IsCBuffer
186 ? llvm::hlsl::ResourceKind::CBuffer
187 : llvm::hlsl::ResourceKind::TBuffer;
188 addBufferResourceAnnotation(GV, RC, RK, /*IsROV=*/false,
189 llvm::hlsl::ElementType::Invalid, Buf.Binding);
190 }
191}
192
194 : Name(D->getName()), IsCBuffer(D->isCBuffer()),
195 Binding(D->getAttr<HLSLResourceBindingAttr>()) {}
196
197void CGHLSLRuntime::addBufferResourceAnnotation(llvm::GlobalVariable *GV,
198 llvm::hlsl::ResourceClass RC,
199 llvm::hlsl::ResourceKind RK,
200 bool IsROV,
201 llvm::hlsl::ElementType ET,
202 BufferResBinding &Binding) {
203 llvm::Module &M = CGM.getModule();
204
205 NamedMDNode *ResourceMD = nullptr;
206 switch (RC) {
207 case llvm::hlsl::ResourceClass::UAV:
208 ResourceMD = M.getOrInsertNamedMetadata("hlsl.uavs");
209 break;
210 case llvm::hlsl::ResourceClass::SRV:
211 ResourceMD = M.getOrInsertNamedMetadata("hlsl.srvs");
212 break;
213 case llvm::hlsl::ResourceClass::CBuffer:
214 ResourceMD = M.getOrInsertNamedMetadata("hlsl.cbufs");
215 break;
216 default:
217 assert(false && "Unsupported buffer type!");
218 return;
219 }
220 assert(ResourceMD != nullptr &&
221 "ResourceMD must have been set by the switch above.");
222
223 llvm::hlsl::FrontendResource Res(
224 GV, RK, ET, IsROV, Binding.Reg.value_or(UINT_MAX), Binding.Space);
225 ResourceMD->addOperand(Res.getMetadata());
226}
227
228static llvm::hlsl::ElementType
229calculateElementType(const ASTContext &Context, const clang::Type *ResourceTy) {
230 using llvm::hlsl::ElementType;
231
232 // TODO: We may need to update this when we add things like ByteAddressBuffer
233 // that don't have a template parameter (or, indeed, an element type).
234 const auto *TST = ResourceTy->getAs<TemplateSpecializationType>();
235 assert(TST && "Resource types must be template specializations");
236 ArrayRef<TemplateArgument> Args = TST->template_arguments();
237 assert(!Args.empty() && "Resource has no element type");
238
239 // At this point we have a resource with an element type, so we can assume
240 // that it's valid or we would have diagnosed the error earlier.
241 QualType ElTy = Args[0].getAsType();
242
243 // We should either have a basic type or a vector of a basic type.
244 if (const auto *VecTy = ElTy->getAs<clang::VectorType>())
245 ElTy = VecTy->getElementType();
246
247 if (ElTy->isSignedIntegerType()) {
248 switch (Context.getTypeSize(ElTy)) {
249 case 16:
250 return ElementType::I16;
251 case 32:
252 return ElementType::I32;
253 case 64:
254 return ElementType::I64;
255 }
256 } else if (ElTy->isUnsignedIntegerType()) {
257 switch (Context.getTypeSize(ElTy)) {
258 case 16:
259 return ElementType::U16;
260 case 32:
261 return ElementType::U32;
262 case 64:
263 return ElementType::U64;
264 }
265 } else if (ElTy->isSpecificBuiltinType(BuiltinType::Half))
266 return ElementType::F16;
267 else if (ElTy->isSpecificBuiltinType(BuiltinType::Float))
268 return ElementType::F32;
269 else if (ElTy->isSpecificBuiltinType(BuiltinType::Double))
270 return ElementType::F64;
271
272 // TODO: We need to handle unorm/snorm float types here once we support them
273 llvm_unreachable("Invalid element type for resource");
274}
275
276void CGHLSLRuntime::annotateHLSLResource(const VarDecl *D, GlobalVariable *GV) {
277 const Type *Ty = D->getType()->getPointeeOrArrayElementType();
278 if (!Ty)
279 return;
280 const auto *RD = Ty->getAsCXXRecordDecl();
281 if (!RD)
282 return;
283 const auto *Attr = RD->getAttr<HLSLResourceAttr>();
284 if (!Attr)
285 return;
286
287 llvm::hlsl::ResourceClass RC = Attr->getResourceClass();
288 llvm::hlsl::ResourceKind RK = Attr->getResourceKind();
289 bool IsROV = Attr->getIsROV();
290 llvm::hlsl::ElementType ET = calculateElementType(CGM.getContext(), Ty);
291
292 BufferResBinding Binding(D->getAttr<HLSLResourceBindingAttr>());
293 addBufferResourceAnnotation(GV, RC, RK, IsROV, ET, Binding);
294}
295
297 HLSLResourceBindingAttr *Binding) {
298 if (Binding) {
299 llvm::APInt RegInt(64, 0);
300 Binding->getSlot().substr(1).getAsInteger(10, RegInt);
301 Reg = RegInt.getLimitedValue();
302 llvm::APInt SpaceInt(64, 0);
303 Binding->getSpace().substr(5).getAsInteger(10, SpaceInt);
304 Space = SpaceInt.getLimitedValue();
305 } else {
306 Space = 0;
307 }
308}
309
311 const FunctionDecl *FD, llvm::Function *Fn) {
312 const auto *ShaderAttr = FD->getAttr<HLSLShaderAttr>();
313 assert(ShaderAttr && "All entry functions must have a HLSLShaderAttr");
314 const StringRef ShaderAttrKindStr = "hlsl.shader";
315 Fn->addFnAttr(ShaderAttrKindStr,
316 ShaderAttr->ConvertShaderTypeToStr(ShaderAttr->getType()));
317 if (HLSLNumThreadsAttr *NumThreadsAttr = FD->getAttr<HLSLNumThreadsAttr>()) {
318 const StringRef NumThreadsKindStr = "hlsl.numthreads";
319 std::string NumThreadsStr =
320 formatv("{0},{1},{2}", NumThreadsAttr->getX(), NumThreadsAttr->getY(),
321 NumThreadsAttr->getZ());
322 Fn->addFnAttr(NumThreadsKindStr, NumThreadsStr);
323 }
324}
325
326static Value *buildVectorInput(IRBuilder<> &B, Function *F, llvm::Type *Ty) {
327 if (const auto *VT = dyn_cast<FixedVectorType>(Ty)) {
328 Value *Result = PoisonValue::get(Ty);
329 for (unsigned I = 0; I < VT->getNumElements(); ++I) {
330 Value *Elt = B.CreateCall(F, {B.getInt32(I)});
331 Result = B.CreateInsertElement(Result, Elt, I);
332 }
333 return Result;
334 }
335 return B.CreateCall(F, {B.getInt32(0)});
336}
337
338llvm::Value *CGHLSLRuntime::emitInputSemantic(IRBuilder<> &B,
339 const ParmVarDecl &D,
340 llvm::Type *Ty) {
341 assert(D.hasAttrs() && "Entry parameter missing annotation attribute!");
342 if (D.hasAttr<HLSLSV_GroupIndexAttr>()) {
343 llvm::Function *DxGroupIndex =
344 CGM.getIntrinsic(Intrinsic::dx_flattened_thread_id_in_group);
345 return B.CreateCall(FunctionCallee(DxGroupIndex));
346 }
347 if (D.hasAttr<HLSLSV_DispatchThreadIDAttr>()) {
348 llvm::Function *ThreadIDIntrinsic =
349 CGM.getIntrinsic(getThreadIdIntrinsic());
350 return buildVectorInput(B, ThreadIDIntrinsic, Ty);
351 }
352 assert(false && "Unhandled parameter attribute");
353 return nullptr;
354}
355
357 llvm::Function *Fn) {
358 llvm::Module &M = CGM.getModule();
359 llvm::LLVMContext &Ctx = M.getContext();
360 auto *EntryTy = llvm::FunctionType::get(llvm::Type::getVoidTy(Ctx), false);
361 Function *EntryFn =
362 Function::Create(EntryTy, Function::ExternalLinkage, FD->getName(), &M);
363
364 // Copy function attributes over, we have no argument or return attributes
365 // that can be valid on the real entry.
366 AttributeList NewAttrs = AttributeList::get(Ctx, AttributeList::FunctionIndex,
367 Fn->getAttributes().getFnAttrs());
368 EntryFn->setAttributes(NewAttrs);
369 setHLSLEntryAttributes(FD, EntryFn);
370
371 // Set the called function as internal linkage.
372 Fn->setLinkage(GlobalValue::InternalLinkage);
373
374 BasicBlock *BB = BasicBlock::Create(Ctx, "entry", EntryFn);
375 IRBuilder<> B(BB);
377 // FIXME: support struct parameters where semantics are on members.
378 // See: https://github.com/llvm/llvm-project/issues/57874
379 unsigned SRetOffset = 0;
380 for (const auto &Param : Fn->args()) {
381 if (Param.hasStructRetAttr()) {
382 // FIXME: support output.
383 // See: https://github.com/llvm/llvm-project/issues/57874
384 SRetOffset = 1;
385 Args.emplace_back(PoisonValue::get(Param.getType()));
386 continue;
387 }
388 const ParmVarDecl *PD = FD->getParamDecl(Param.getArgNo() - SRetOffset);
389 Args.push_back(emitInputSemantic(B, *PD, Param.getType()));
390 }
391
392 CallInst *CI = B.CreateCall(FunctionCallee(Fn), Args);
393 (void)CI;
394 // FIXME: Handle codegen for return type semantics.
395 // See: https://github.com/llvm/llvm-project/issues/57875
396 B.CreateRetVoid();
397}
398
399static void gatherFunctions(SmallVectorImpl<Function *> &Fns, llvm::Module &M,
400 bool CtorOrDtor) {
401 const auto *GV =
402 M.getNamedGlobal(CtorOrDtor ? "llvm.global_ctors" : "llvm.global_dtors");
403 if (!GV)
404 return;
405 const auto *CA = dyn_cast<ConstantArray>(GV->getInitializer());
406 if (!CA)
407 return;
408 // The global_ctor array elements are a struct [Priority, Fn *, COMDat].
409 // HLSL neither supports priorities or COMDat values, so we will check those
410 // in an assert but not handle them.
411
413 for (const auto &Ctor : CA->operands()) {
414 if (isa<ConstantAggregateZero>(Ctor))
415 continue;
416 ConstantStruct *CS = cast<ConstantStruct>(Ctor);
417
418 assert(cast<ConstantInt>(CS->getOperand(0))->getValue() == 65535 &&
419 "HLSL doesn't support setting priority for global ctors.");
420 assert(isa<ConstantPointerNull>(CS->getOperand(2)) &&
421 "HLSL doesn't support COMDat for global ctors.");
422 Fns.push_back(cast<Function>(CS->getOperand(1)));
423 }
424}
425
427 llvm::Module &M = CGM.getModule();
430 gatherFunctions(CtorFns, M, true);
431 gatherFunctions(DtorFns, M, false);
432
433 // Insert a call to the global constructor at the beginning of the entry block
434 // to externally exported functions. This is a bit of a hack, but HLSL allows
435 // global constructors, but doesn't support driver initialization of globals.
436 for (auto &F : M.functions()) {
437 if (!F.hasFnAttribute("hlsl.shader"))
438 continue;
439 IRBuilder<> B(&F.getEntryBlock(), F.getEntryBlock().begin());
440 for (auto *Fn : CtorFns)
441 B.CreateCall(FunctionCallee(Fn));
442
443 // Insert global dtors before the terminator of the last instruction
444 B.SetInsertPoint(F.back().getTerminator());
445 for (auto *Fn : DtorFns)
446 B.CreateCall(FunctionCallee(Fn));
447 }
448
449 // No need to keep global ctors/dtors for non-lib profile after call to
450 // ctors/dtors added for entry.
451 Triple T(M.getTargetTriple());
452 if (T.getEnvironment() != Triple::EnvironmentType::Library) {
453 if (auto *GV = M.getNamedGlobal("llvm.global_ctors"))
454 GV->eraseFromParent();
455 if (auto *GV = M.getNamedGlobal("llvm.global_dtors"))
456 GV->eraseFromParent();
457 }
458}
static llvm::hlsl::ElementType calculateElementType(const ASTContext &Context, const clang::Type *ResourceTy)
static void gatherFunctions(SmallVectorImpl< Function * > &Fns, llvm::Module &M, bool CtorOrDtor)
static Value * buildVectorInput(IRBuilder<> &B, Function *F, llvm::Type *Ty)
static std::string getName(const CallEvent &Call)
Defines the clang::TargetOptions class.
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:182
uint64_t getTypeSize(QualType T) const
Return the size of the specified (complete) type T, in bits.
Definition: ASTContext.h:2341
Attr - This represents one attribute.
Definition: Attr.h:42
This class gathers all debug information during compilation and is responsible for emitting to llvm g...
Definition: CGDebugInfo.h:55
void setHLSLEntryAttributes(const FunctionDecl *FD, llvm::Function *Fn)
void emitEntryFunction(const FunctionDecl *FD, llvm::Function *Fn)
llvm::Value * emitInputSemantic(llvm::IRBuilder<> &B, const ParmVarDecl &D, llvm::Type *Ty)
void annotateHLSLResource(const VarDecl *D, llvm::GlobalVariable *GV)
void addBuffer(const HLSLBufferDecl *D)
llvm::Module & getModule() const
CGDebugInfo * getModuleDebugInfo()
const TargetInfo & getTarget() const
void EmitGlobal(GlobalDecl D)
Emit code for a single global function or var decl.
ASTContext & getContext() const
llvm::Constant * GetAddrOfGlobalVar(const VarDecl *D, llvm::Type *Ty=nullptr, ForDefinition_t IsForDefinition=NotForDefinition)
Return the llvm::Constant for the address of the given global variable.
const CodeGenOptions & getCodeGenOpts() const
llvm::Function * getIntrinsic(unsigned IID, ArrayRef< llvm::Type * > Tys=std::nullopt)
void EmitTopLevelDecl(Decl *D)
Emit code for a single top level declaration.
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1436
decl_range decls() const
decls_begin/decls_end - Iterate over the declarations stored in this context.
Definition: DeclBase.h:2322
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:86
T * getAttr() const
Definition: DeclBase.h:579
bool hasAttrs() const
Definition: DeclBase.h:524
bool hasAttr() const
Definition: DeclBase.h:583
Represents a function declaration or definition.
Definition: Decl.h:1971
const ParmVarDecl * getParamDecl(unsigned i) const
Definition: Decl.h:2706
HLSLBufferDecl - Represent a cbuffer or tbuffer declaration.
Definition: Decl.h:4940
StringRef getName() const
Get the name of identifier for this declaration as a StringRef.
Definition: Decl.h:276
Represents a parameter to a function.
Definition: Decl.h:1761
A (possibly-)qualified type.
Definition: Type.h:940
TargetOptions & getTargetOpts() const
Retrieve the target options.
Definition: TargetInfo.h:312
const llvm::Triple & getTriple() const
Returns the target triple of the primary target.
Definition: TargetInfo.h:1256
Represents a type template specialization; the template must be a class template, a type alias templa...
Definition: Type.h:6090
The base class of the type hierarchy.
Definition: Type.h:1813
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1871
const Type * getPointeeOrArrayElementType() const
If this is a pointer type, return the pointee type.
Definition: Type.h:8088
bool isSignedIntegerType() const
Return true if this is an integer type that is signed, according to C99 6.2.5p4 [char,...
Definition: Type.cpp:2135
bool isSpecificBuiltinType(unsigned K) const
Test for a particular builtin type.
Definition: Type.h:7879
bool isUnsignedIntegerType() const
Return true if this is an integer type that is unsigned, according to C99 6.2.5p6 [which returns true...
Definition: Type.cpp:2185
const T * getAs() const
Member-template getAs<specific type>'.
Definition: Type.h:8131
QualType getType() const
Definition: Decl.h:717
Represents a variable declaration or definition.
Definition: Decl.h:918
StorageClass getStorageClass() const
Returns the storage class as written in the source.
Definition: Decl.h:1155
Represents a GCC generic vector type.
Definition: Type.h:3970
#define UINT_MAX
Definition: limits.h:64
bool Const(InterpState &S, CodePtr OpPC, const T &Arg)
Definition: Interp.h:939
The JSON file list parser is used to communicate input to InstallAPI.
@ SC_Static
Definition: Specifiers.h:249
@ Result
The result type of a method or function.
const FunctionProtoType * T
unsigned long uint64_t
Diagnostic wrappers for TextAPI types for error reporting.
Definition: Dominators.h:30
BufferResBinding(HLSLResourceBindingAttr *Attr)
std::vector< std::pair< llvm::GlobalVariable *, unsigned > > Constants
Definition: CGHLSLRuntime.h:99