1 //===----- CGCUDANV.cpp - Interface to NVIDIA CUDA Runtime ----------------===//
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
7 //===----------------------------------------------------------------------===//
9 // This provides a class for CUDA code generation targeting the NVIDIA CUDA
12 //===----------------------------------------------------------------------===//
14 #include "CGCUDARuntime.h"
15 #include "CodeGenFunction.h"
16 #include "CodeGenModule.h"
17 #include "clang/AST/Decl.h"
18 #include "clang/Basic/Cuda.h"
19 #include "clang/CodeGen/CodeGenABITypes.h"
20 #include "clang/CodeGen/ConstantInitBuilder.h"
21 #include "llvm/IR/BasicBlock.h"
22 #include "llvm/IR/Constants.h"
23 #include "llvm/IR/DerivedTypes.h"
24 #include "llvm/Support/Format.h"
26 using namespace clang;
27 using namespace CodeGen;
30 constexpr unsigned CudaFatMagic = 0x466243b1;
31 constexpr unsigned HIPFatMagic = 0x48495046; // "HIPF"
33 class CGNVCUDARuntime : public CGCUDARuntime {
36 llvm::IntegerType *IntTy, *SizeTy;
38 llvm::PointerType *CharPtrTy, *VoidPtrTy, *VoidPtrPtrTy;
40 /// Convenience reference to LLVM Context
41 llvm::LLVMContext &Context;
42 /// Convenience reference to the current module
43 llvm::Module &TheModule;
44 /// Keeps track of kernel launch stubs emitted in this module
46 llvm::Function *Kernel;
49 llvm::SmallVector<KernelInfo, 16> EmittedKernels;
51 llvm::GlobalVariable *Var;
55 llvm::SmallVector<VarInfo, 16> DeviceVars;
56 /// Keeps track of variable containing handle of GPU binary. Populated by
57 /// ModuleCtorFunction() and used to create corresponding cleanup calls in
58 /// ModuleDtorFunction()
59 llvm::GlobalVariable *GpuBinaryHandle = nullptr;
60 /// Whether we generate relocatable device code.
61 bool RelocatableDeviceCode;
62 /// Mangle context for device.
63 std::unique_ptr<MangleContext> DeviceMC;
65 llvm::FunctionCallee getSetupArgumentFn() const;
66 llvm::FunctionCallee getLaunchFn() const;
68 llvm::FunctionType *getRegisterGlobalsFnTy() const;
69 llvm::FunctionType *getCallbackFnTy() const;
70 llvm::FunctionType *getRegisterLinkedBinaryFnTy() const;
71 std::string addPrefixToName(StringRef FuncName) const;
72 std::string addUnderscoredPrefixToName(StringRef FuncName) const;
74 /// Creates a function to register all kernel stubs generated in this module.
75 llvm::Function *makeRegisterGlobalsFn();
77 /// Helper function that generates a constant string and returns a pointer to
78 /// the start of the string. The result of this function can be used anywhere
79 /// where the C code specifies const char*.
80 llvm::Constant *makeConstantString(const std::string &Str,
81 const std::string &Name = "",
82 const std::string &SectionName = "",
83 unsigned Alignment = 0) {
84 llvm::Constant *Zeros[] = {llvm::ConstantInt::get(SizeTy, 0),
85 llvm::ConstantInt::get(SizeTy, 0)};
86 auto ConstStr = CGM.GetAddrOfConstantCString(Str, Name.c_str());
87 llvm::GlobalVariable *GV =
88 cast<llvm::GlobalVariable>(ConstStr.getPointer());
89 if (!SectionName.empty()) {
90 GV->setSection(SectionName);
91 // Mark the address as used which make sure that this section isn't
92 // merged and we will really have it in the object file.
93 GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::None);
96 GV->setAlignment(llvm::Align(Alignment));
98 return llvm::ConstantExpr::getGetElementPtr(ConstStr.getElementType(),
99 ConstStr.getPointer(), Zeros);
102 /// Helper function that generates an empty dummy function returning void.
103 llvm::Function *makeDummyFunction(llvm::FunctionType *FnTy) {
104 assert(FnTy->getReturnType()->isVoidTy() &&
105 "Can only generate dummy functions returning void!");
106 llvm::Function *DummyFunc = llvm::Function::Create(
107 FnTy, llvm::GlobalValue::InternalLinkage, "dummy", &TheModule);
109 llvm::BasicBlock *DummyBlock =
110 llvm::BasicBlock::Create(Context, "", DummyFunc);
111 CGBuilderTy FuncBuilder(CGM, Context);
112 FuncBuilder.SetInsertPoint(DummyBlock);
113 FuncBuilder.CreateRetVoid();
118 void emitDeviceStubBodyLegacy(CodeGenFunction &CGF, FunctionArgList &Args);
119 void emitDeviceStubBodyNew(CodeGenFunction &CGF, FunctionArgList &Args);
120 std::string getDeviceSideName(const Decl *ND);
123 CGNVCUDARuntime(CodeGenModule &CGM);
125 void emitDeviceStub(CodeGenFunction &CGF, FunctionArgList &Args) override;
126 void registerDeviceVar(const VarDecl *VD, llvm::GlobalVariable &Var,
127 unsigned Flags) override {
128 DeviceVars.push_back({&Var, VD, Flags});
131 /// Creates module constructor function
132 llvm::Function *makeModuleCtorFunction() override;
133 /// Creates module destructor function
134 llvm::Function *makeModuleDtorFunction() override;
135 /// Construct and return the stub name of a kernel.
136 std::string getDeviceStubName(llvm::StringRef Name) const override;
141 std::string CGNVCUDARuntime::addPrefixToName(StringRef FuncName) const {
142 if (CGM.getLangOpts().HIP)
143 return ((Twine("hip") + Twine(FuncName)).str());
144 return ((Twine("cuda") + Twine(FuncName)).str());
147 CGNVCUDARuntime::addUnderscoredPrefixToName(StringRef FuncName) const {
148 if (CGM.getLangOpts().HIP)
149 return ((Twine("__hip") + Twine(FuncName)).str());
150 return ((Twine("__cuda") + Twine(FuncName)).str());
153 CGNVCUDARuntime::CGNVCUDARuntime(CodeGenModule &CGM)
154 : CGCUDARuntime(CGM), Context(CGM.getLLVMContext()),
155 TheModule(CGM.getModule()),
156 RelocatableDeviceCode(CGM.getLangOpts().GPURelocatableDeviceCode),
157 DeviceMC(CGM.getContext().createMangleContext(
158 CGM.getContext().getAuxTargetInfo())) {
159 CodeGen::CodeGenTypes &Types = CGM.getTypes();
160 ASTContext &Ctx = CGM.getContext();
166 CharPtrTy = llvm::PointerType::getUnqual(Types.ConvertType(Ctx.CharTy));
167 VoidPtrTy = cast<llvm::PointerType>(Types.ConvertType(Ctx.VoidPtrTy));
168 VoidPtrPtrTy = VoidPtrTy->getPointerTo();
171 llvm::FunctionCallee CGNVCUDARuntime::getSetupArgumentFn() const {
172 // cudaError_t cudaSetupArgument(void *, size_t, size_t)
173 llvm::Type *Params[] = {VoidPtrTy, SizeTy, SizeTy};
174 return CGM.CreateRuntimeFunction(
175 llvm::FunctionType::get(IntTy, Params, false),
176 addPrefixToName("SetupArgument"));
179 llvm::FunctionCallee CGNVCUDARuntime::getLaunchFn() const {
180 if (CGM.getLangOpts().HIP) {
181 // hipError_t hipLaunchByPtr(char *);
182 return CGM.CreateRuntimeFunction(
183 llvm::FunctionType::get(IntTy, CharPtrTy, false), "hipLaunchByPtr");
185 // cudaError_t cudaLaunch(char *);
186 return CGM.CreateRuntimeFunction(
187 llvm::FunctionType::get(IntTy, CharPtrTy, false), "cudaLaunch");
191 llvm::FunctionType *CGNVCUDARuntime::getRegisterGlobalsFnTy() const {
192 return llvm::FunctionType::get(VoidTy, VoidPtrPtrTy, false);
195 llvm::FunctionType *CGNVCUDARuntime::getCallbackFnTy() const {
196 return llvm::FunctionType::get(VoidTy, VoidPtrTy, false);
199 llvm::FunctionType *CGNVCUDARuntime::getRegisterLinkedBinaryFnTy() const {
200 auto CallbackFnTy = getCallbackFnTy();
201 auto RegisterGlobalsFnTy = getRegisterGlobalsFnTy();
202 llvm::Type *Params[] = {RegisterGlobalsFnTy->getPointerTo(), VoidPtrTy,
203 VoidPtrTy, CallbackFnTy->getPointerTo()};
204 return llvm::FunctionType::get(VoidTy, Params, false);
207 std::string CGNVCUDARuntime::getDeviceSideName(const Decl *D) {
208 auto *ND = cast<const NamedDecl>(D);
209 std::string DeviceSideName;
210 if (DeviceMC->shouldMangleDeclName(ND)) {
211 SmallString<256> Buffer;
212 llvm::raw_svector_ostream Out(Buffer);
213 DeviceMC->mangleName(ND, Out);
214 DeviceSideName = Out.str();
216 DeviceSideName = ND->getIdentifier()->getName();
217 return DeviceSideName;
220 void CGNVCUDARuntime::emitDeviceStub(CodeGenFunction &CGF,
221 FunctionArgList &Args) {
222 // Ensure either we have different ABIs between host and device compilations,
223 // says host compilation following MSVC ABI but device compilation follows
224 // Itanium C++ ABI or, if they follow the same ABI, kernel names after
225 // mangling should be the same after name stubbing. The later checking is
226 // very important as the device kernel name being mangled in host-compilation
227 // is used to resolve the device binaries to be executed. Inconsistent naming
228 // result in undefined behavior. Even though we cannot check that naming
229 // directly between host- and device-compilations, the host- and
230 // device-mangling in host compilation could help catching certain ones.
231 assert((CGF.CGM.getContext().getAuxTargetInfo() &&
232 (CGF.CGM.getContext().getAuxTargetInfo()->getCXXABI() !=
233 CGF.CGM.getContext().getTargetInfo().getCXXABI())) ||
234 getDeviceStubName(getDeviceSideName(CGF.CurFuncDecl)) ==
235 CGF.CurFn->getName());
237 EmittedKernels.push_back({CGF.CurFn, CGF.CurFuncDecl});
238 if (CudaFeatureEnabled(CGM.getTarget().getSDKVersion(),
239 CudaFeature::CUDA_USES_NEW_LAUNCH) ||
240 CGF.getLangOpts().HIPUseNewLaunchAPI)
241 emitDeviceStubBodyNew(CGF, Args);
243 emitDeviceStubBodyLegacy(CGF, Args);
246 // CUDA 9.0+ uses new way to launch kernels. Parameters are packed in a local
247 // array and kernels are launched using cudaLaunchKernel().
248 void CGNVCUDARuntime::emitDeviceStubBodyNew(CodeGenFunction &CGF,
249 FunctionArgList &Args) {
250 // Build the shadow stack entry at the very start of the function.
252 // Calculate amount of space we will need for all arguments. If we have no
253 // args, allocate a single pointer so we still have a valid pointer to the
254 // argument array that we can pass to runtime, even if it will be unused.
255 Address KernelArgs = CGF.CreateTempAlloca(
256 VoidPtrTy, CharUnits::fromQuantity(16), "kernel_args",
257 llvm::ConstantInt::get(SizeTy, std::max<size_t>(1, Args.size())));
258 // Store pointers to the arguments in a locally allocated launch_args.
259 for (unsigned i = 0; i < Args.size(); ++i) {
260 llvm::Value* VarPtr = CGF.GetAddrOfLocalVar(Args[i]).getPointer();
261 llvm::Value *VoidVarPtr = CGF.Builder.CreatePointerCast(VarPtr, VoidPtrTy);
262 CGF.Builder.CreateDefaultAlignedStore(
263 VoidVarPtr, CGF.Builder.CreateConstGEP1_32(KernelArgs.getPointer(), i));
266 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("setup.end");
268 // Lookup cudaLaunchKernel/hipLaunchKernel function.
269 // cudaError_t cudaLaunchKernel(const void *func, dim3 gridDim, dim3 blockDim,
270 // void **args, size_t sharedMem,
271 // cudaStream_t stream);
272 // hipError_t hipLaunchKernel(const void *func, dim3 gridDim, dim3 blockDim,
273 // void **args, size_t sharedMem,
274 // hipStream_t stream);
275 TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl();
276 DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
277 auto LaunchKernelName = addPrefixToName("LaunchKernel");
278 IdentifierInfo &cudaLaunchKernelII =
279 CGM.getContext().Idents.get(LaunchKernelName);
280 FunctionDecl *cudaLaunchKernelFD = nullptr;
281 for (const auto &Result : DC->lookup(&cudaLaunchKernelII)) {
282 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(Result))
283 cudaLaunchKernelFD = FD;
286 if (cudaLaunchKernelFD == nullptr) {
287 CGM.Error(CGF.CurFuncDecl->getLocation(),
288 "Can't find declaration for " + LaunchKernelName);
291 // Create temporary dim3 grid_dim, block_dim.
292 ParmVarDecl *GridDimParam = cudaLaunchKernelFD->getParamDecl(1);
293 QualType Dim3Ty = GridDimParam->getType();
295 CGF.CreateMemTemp(Dim3Ty, CharUnits::fromQuantity(8), "grid_dim");
297 CGF.CreateMemTemp(Dim3Ty, CharUnits::fromQuantity(8), "block_dim");
299 CGF.CreateTempAlloca(SizeTy, CGM.getSizeAlign(), "shmem_size");
301 CGF.CreateTempAlloca(VoidPtrTy, CGM.getPointerAlign(), "stream");
302 llvm::FunctionCallee cudaPopConfigFn = CGM.CreateRuntimeFunction(
303 llvm::FunctionType::get(IntTy,
304 {/*gridDim=*/GridDim.getType(),
305 /*blockDim=*/BlockDim.getType(),
306 /*ShmemSize=*/ShmemSize.getType(),
307 /*Stream=*/Stream.getType()},
309 addUnderscoredPrefixToName("PopCallConfiguration"));
311 CGF.EmitRuntimeCallOrInvoke(cudaPopConfigFn,
312 {GridDim.getPointer(), BlockDim.getPointer(),
313 ShmemSize.getPointer(), Stream.getPointer()});
315 // Emit the call to cudaLaunch
316 llvm::Value *Kernel = CGF.Builder.CreatePointerCast(CGF.CurFn, VoidPtrTy);
317 CallArgList LaunchKernelArgs;
318 LaunchKernelArgs.add(RValue::get(Kernel),
319 cudaLaunchKernelFD->getParamDecl(0)->getType());
320 LaunchKernelArgs.add(RValue::getAggregate(GridDim), Dim3Ty);
321 LaunchKernelArgs.add(RValue::getAggregate(BlockDim), Dim3Ty);
322 LaunchKernelArgs.add(RValue::get(KernelArgs.getPointer()),
323 cudaLaunchKernelFD->getParamDecl(3)->getType());
324 LaunchKernelArgs.add(RValue::get(CGF.Builder.CreateLoad(ShmemSize)),
325 cudaLaunchKernelFD->getParamDecl(4)->getType());
326 LaunchKernelArgs.add(RValue::get(CGF.Builder.CreateLoad(Stream)),
327 cudaLaunchKernelFD->getParamDecl(5)->getType());
329 QualType QT = cudaLaunchKernelFD->getType();
330 QualType CQT = QT.getCanonicalType();
331 llvm::Type *Ty = CGM.getTypes().ConvertType(CQT);
332 llvm::FunctionType *FTy = dyn_cast<llvm::FunctionType>(Ty);
334 const CGFunctionInfo &FI =
335 CGM.getTypes().arrangeFunctionDeclaration(cudaLaunchKernelFD);
336 llvm::FunctionCallee cudaLaunchKernelFn =
337 CGM.CreateRuntimeFunction(FTy, LaunchKernelName);
338 CGF.EmitCall(FI, CGCallee::forDirect(cudaLaunchKernelFn), ReturnValueSlot(),
340 CGF.EmitBranch(EndBlock);
342 CGF.EmitBlock(EndBlock);
345 void CGNVCUDARuntime::emitDeviceStubBodyLegacy(CodeGenFunction &CGF,
346 FunctionArgList &Args) {
347 // Emit a call to cudaSetupArgument for each arg in Args.
348 llvm::FunctionCallee cudaSetupArgFn = getSetupArgumentFn();
349 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("setup.end");
350 CharUnits Offset = CharUnits::Zero();
351 for (const VarDecl *A : Args) {
352 CharUnits TyWidth, TyAlign;
353 std::tie(TyWidth, TyAlign) =
354 CGM.getContext().getTypeInfoInChars(A->getType());
355 Offset = Offset.alignTo(TyAlign);
356 llvm::Value *Args[] = {
357 CGF.Builder.CreatePointerCast(CGF.GetAddrOfLocalVar(A).getPointer(),
359 llvm::ConstantInt::get(SizeTy, TyWidth.getQuantity()),
360 llvm::ConstantInt::get(SizeTy, Offset.getQuantity()),
362 llvm::CallBase *CB = CGF.EmitRuntimeCallOrInvoke(cudaSetupArgFn, Args);
363 llvm::Constant *Zero = llvm::ConstantInt::get(IntTy, 0);
364 llvm::Value *CBZero = CGF.Builder.CreateICmpEQ(CB, Zero);
365 llvm::BasicBlock *NextBlock = CGF.createBasicBlock("setup.next");
366 CGF.Builder.CreateCondBr(CBZero, NextBlock, EndBlock);
367 CGF.EmitBlock(NextBlock);
371 // Emit the call to cudaLaunch
372 llvm::FunctionCallee cudaLaunchFn = getLaunchFn();
373 llvm::Value *Arg = CGF.Builder.CreatePointerCast(CGF.CurFn, CharPtrTy);
374 CGF.EmitRuntimeCallOrInvoke(cudaLaunchFn, Arg);
375 CGF.EmitBranch(EndBlock);
377 CGF.EmitBlock(EndBlock);
380 /// Creates a function that sets up state on the host side for CUDA objects that
381 /// have a presence on both the host and device sides. Specifically, registers
382 /// the host side of kernel functions and device global variables with the CUDA
385 /// void __cuda_register_globals(void** GpuBinaryHandle) {
386 /// __cudaRegisterFunction(GpuBinaryHandle,Kernel0,...);
388 /// __cudaRegisterFunction(GpuBinaryHandle,KernelM,...);
389 /// __cudaRegisterVar(GpuBinaryHandle, GlobalVar0, ...);
391 /// __cudaRegisterVar(GpuBinaryHandle, GlobalVarN, ...);
394 llvm::Function *CGNVCUDARuntime::makeRegisterGlobalsFn() {
395 // No need to register anything
396 if (EmittedKernels.empty() && DeviceVars.empty())
399 llvm::Function *RegisterKernelsFunc = llvm::Function::Create(
400 getRegisterGlobalsFnTy(), llvm::GlobalValue::InternalLinkage,
401 addUnderscoredPrefixToName("_register_globals"), &TheModule);
402 llvm::BasicBlock *EntryBB =
403 llvm::BasicBlock::Create(Context, "entry", RegisterKernelsFunc);
404 CGBuilderTy Builder(CGM, Context);
405 Builder.SetInsertPoint(EntryBB);
407 // void __cudaRegisterFunction(void **, const char *, char *, const char *,
408 // int, uint3*, uint3*, dim3*, dim3*, int*)
409 llvm::Type *RegisterFuncParams[] = {
410 VoidPtrPtrTy, CharPtrTy, CharPtrTy, CharPtrTy, IntTy,
411 VoidPtrTy, VoidPtrTy, VoidPtrTy, VoidPtrTy, IntTy->getPointerTo()};
412 llvm::FunctionCallee RegisterFunc = CGM.CreateRuntimeFunction(
413 llvm::FunctionType::get(IntTy, RegisterFuncParams, false),
414 addUnderscoredPrefixToName("RegisterFunction"));
416 // Extract GpuBinaryHandle passed as the first argument passed to
417 // __cuda_register_globals() and generate __cudaRegisterFunction() call for
418 // each emitted kernel.
419 llvm::Argument &GpuBinaryHandlePtr = *RegisterKernelsFunc->arg_begin();
420 for (auto &&I : EmittedKernels) {
421 llvm::Constant *KernelName = makeConstantString(getDeviceSideName(I.D));
422 llvm::Constant *NullPtr = llvm::ConstantPointerNull::get(VoidPtrTy);
423 llvm::Value *Args[] = {
425 Builder.CreateBitCast(I.Kernel, VoidPtrTy),
428 llvm::ConstantInt::get(IntTy, -1),
433 llvm::ConstantPointerNull::get(IntTy->getPointerTo())};
434 Builder.CreateCall(RegisterFunc, Args);
437 // void __cudaRegisterVar(void **, char *, char *, const char *,
438 // int, int, int, int)
439 llvm::Type *RegisterVarParams[] = {VoidPtrPtrTy, CharPtrTy, CharPtrTy,
440 CharPtrTy, IntTy, IntTy,
442 llvm::FunctionCallee RegisterVar = CGM.CreateRuntimeFunction(
443 llvm::FunctionType::get(IntTy, RegisterVarParams, false),
444 addUnderscoredPrefixToName("RegisterVar"));
445 for (auto &&Info : DeviceVars) {
446 llvm::GlobalVariable *Var = Info.Var;
447 unsigned Flags = Info.Flag;
448 llvm::Constant *VarName = makeConstantString(getDeviceSideName(Info.D));
450 CGM.getDataLayout().getTypeAllocSize(Var->getValueType());
451 llvm::Value *Args[] = {
453 Builder.CreateBitCast(Var, VoidPtrTy),
456 llvm::ConstantInt::get(IntTy, (Flags & ExternDeviceVar) ? 1 : 0),
457 llvm::ConstantInt::get(IntTy, VarSize),
458 llvm::ConstantInt::get(IntTy, (Flags & ConstantDeviceVar) ? 1 : 0),
459 llvm::ConstantInt::get(IntTy, 0)};
460 Builder.CreateCall(RegisterVar, Args);
463 Builder.CreateRetVoid();
464 return RegisterKernelsFunc;
467 /// Creates a global constructor function for the module:
471 /// void __cuda_module_ctor(void*) {
472 /// Handle = __cudaRegisterFatBinary(GpuBinaryBlob);
473 /// __cuda_register_globals(Handle);
479 /// void __hip_module_ctor(void*) {
480 /// if (__hip_gpubin_handle == 0) {
481 /// __hip_gpubin_handle = __hipRegisterFatBinary(GpuBinaryBlob);
482 /// __hip_register_globals(__hip_gpubin_handle);
486 llvm::Function *CGNVCUDARuntime::makeModuleCtorFunction() {
487 bool IsHIP = CGM.getLangOpts().HIP;
488 bool IsCUDA = CGM.getLangOpts().CUDA;
489 // No need to generate ctors/dtors if there is no GPU binary.
490 StringRef CudaGpuBinaryFileName = CGM.getCodeGenOpts().CudaGpuBinaryFileName;
491 if (CudaGpuBinaryFileName.empty() && !IsHIP)
493 if ((IsHIP || (IsCUDA && !RelocatableDeviceCode)) && EmittedKernels.empty() &&
497 // void __{cuda|hip}_register_globals(void* handle);
498 llvm::Function *RegisterGlobalsFunc = makeRegisterGlobalsFn();
499 // We always need a function to pass in as callback. Create a dummy
500 // implementation if we don't need to register anything.
501 if (RelocatableDeviceCode && !RegisterGlobalsFunc)
502 RegisterGlobalsFunc = makeDummyFunction(getRegisterGlobalsFnTy());
504 // void ** __{cuda|hip}RegisterFatBinary(void *);
505 llvm::FunctionCallee RegisterFatbinFunc = CGM.CreateRuntimeFunction(
506 llvm::FunctionType::get(VoidPtrPtrTy, VoidPtrTy, false),
507 addUnderscoredPrefixToName("RegisterFatBinary"));
508 // struct { int magic, int version, void * gpu_binary, void * dont_care };
509 llvm::StructType *FatbinWrapperTy =
510 llvm::StructType::get(IntTy, IntTy, VoidPtrTy, VoidPtrTy);
512 // Register GPU binary with the CUDA runtime, store returned handle in a
513 // global variable and save a reference in GpuBinaryHandle to be cleaned up
514 // in destructor on exit. Then associate all known kernels with the GPU binary
515 // handle so CUDA runtime can figure out what to call on the GPU side.
516 std::unique_ptr<llvm::MemoryBuffer> CudaGpuBinary = nullptr;
517 if (!CudaGpuBinaryFileName.empty()) {
518 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> CudaGpuBinaryOrErr =
519 llvm::MemoryBuffer::getFileOrSTDIN(CudaGpuBinaryFileName);
520 if (std::error_code EC = CudaGpuBinaryOrErr.getError()) {
521 CGM.getDiags().Report(diag::err_cannot_open_file)
522 << CudaGpuBinaryFileName << EC.message();
525 CudaGpuBinary = std::move(CudaGpuBinaryOrErr.get());
528 llvm::Function *ModuleCtorFunc = llvm::Function::Create(
529 llvm::FunctionType::get(VoidTy, VoidPtrTy, false),
530 llvm::GlobalValue::InternalLinkage,
531 addUnderscoredPrefixToName("_module_ctor"), &TheModule);
532 llvm::BasicBlock *CtorEntryBB =
533 llvm::BasicBlock::Create(Context, "entry", ModuleCtorFunc);
534 CGBuilderTy CtorBuilder(CGM, Context);
536 CtorBuilder.SetInsertPoint(CtorEntryBB);
538 const char *FatbinConstantName;
539 const char *FatbinSectionName;
540 const char *ModuleIDSectionName;
541 StringRef ModuleIDPrefix;
542 llvm::Constant *FatBinStr;
545 FatbinConstantName = ".hip_fatbin";
546 FatbinSectionName = ".hipFatBinSegment";
548 ModuleIDSectionName = "__hip_module_id";
549 ModuleIDPrefix = "__hip_";
552 // If fatbin is available from early finalization, create a string
553 // literal containing the fat binary loaded from the given file.
554 FatBinStr = makeConstantString(CudaGpuBinary->getBuffer(), "",
555 FatbinConstantName, 8);
557 // If fatbin is not available, create an external symbol
558 // __hip_fatbin in section .hip_fatbin. The external symbol is supposed
559 // to contain the fat binary but will be populated somewhere else,
560 // e.g. by lld through link script.
561 FatBinStr = new llvm::GlobalVariable(
562 CGM.getModule(), CGM.Int8Ty,
563 /*isConstant=*/true, llvm::GlobalValue::ExternalLinkage, nullptr,
564 "__hip_fatbin", nullptr,
565 llvm::GlobalVariable::NotThreadLocal);
566 cast<llvm::GlobalVariable>(FatBinStr)->setSection(FatbinConstantName);
569 FatMagic = HIPFatMagic;
571 if (RelocatableDeviceCode)
572 FatbinConstantName = CGM.getTriple().isMacOSX()
573 ? "__NV_CUDA,__nv_relfatbin"
577 CGM.getTriple().isMacOSX() ? "__NV_CUDA,__nv_fatbin" : ".nv_fatbin";
578 // NVIDIA's cuobjdump looks for fatbins in this section.
580 CGM.getTriple().isMacOSX() ? "__NV_CUDA,__fatbin" : ".nvFatBinSegment";
582 ModuleIDSectionName = CGM.getTriple().isMacOSX()
583 ? "__NV_CUDA,__nv_module_id"
585 ModuleIDPrefix = "__nv_";
587 // For CUDA, create a string literal containing the fat binary loaded from
589 FatBinStr = makeConstantString(CudaGpuBinary->getBuffer(), "",
590 FatbinConstantName, 8);
591 FatMagic = CudaFatMagic;
594 // Create initialized wrapper structure that points to the loaded GPU binary
595 ConstantInitBuilder Builder(CGM);
596 auto Values = Builder.beginStruct(FatbinWrapperTy);
597 // Fatbin wrapper magic.
598 Values.addInt(IntTy, FatMagic);
600 Values.addInt(IntTy, 1);
602 Values.add(FatBinStr);
603 // Unused in fatbin v1.
604 Values.add(llvm::ConstantPointerNull::get(VoidPtrTy));
605 llvm::GlobalVariable *FatbinWrapper = Values.finishAndCreateGlobal(
606 addUnderscoredPrefixToName("_fatbin_wrapper"), CGM.getPointerAlign(),
608 FatbinWrapper->setSection(FatbinSectionName);
610 // There is only one HIP fat binary per linked module, however there are
611 // multiple constructor functions. Make sure the fat binary is registered
612 // only once. The constructor functions are executed by the dynamic loader
613 // before the program gains control. The dynamic loader cannot execute the
614 // constructor functions concurrently since doing that would not guarantee
615 // thread safety of the loaded program. Therefore we can assume sequential
616 // execution of constructor functions here.
618 auto Linkage = CudaGpuBinary ? llvm::GlobalValue::InternalLinkage :
619 llvm::GlobalValue::LinkOnceAnyLinkage;
620 llvm::BasicBlock *IfBlock =
621 llvm::BasicBlock::Create(Context, "if", ModuleCtorFunc);
622 llvm::BasicBlock *ExitBlock =
623 llvm::BasicBlock::Create(Context, "exit", ModuleCtorFunc);
624 // The name, size, and initialization pattern of this variable is part
626 GpuBinaryHandle = new llvm::GlobalVariable(
627 TheModule, VoidPtrPtrTy, /*isConstant=*/false,
629 /*Initializer=*/llvm::ConstantPointerNull::get(VoidPtrPtrTy),
630 "__hip_gpubin_handle");
631 GpuBinaryHandle->setAlignment(CGM.getPointerAlign().getAsAlign());
632 // Prevent the weak symbol in different shared libraries being merged.
633 if (Linkage != llvm::GlobalValue::InternalLinkage)
634 GpuBinaryHandle->setVisibility(llvm::GlobalValue::HiddenVisibility);
635 Address GpuBinaryAddr(
637 CharUnits::fromQuantity(GpuBinaryHandle->getAlignment()));
639 auto HandleValue = CtorBuilder.CreateLoad(GpuBinaryAddr);
640 llvm::Constant *Zero =
641 llvm::Constant::getNullValue(HandleValue->getType());
642 llvm::Value *EQZero = CtorBuilder.CreateICmpEQ(HandleValue, Zero);
643 CtorBuilder.CreateCondBr(EQZero, IfBlock, ExitBlock);
646 CtorBuilder.SetInsertPoint(IfBlock);
647 // GpuBinaryHandle = __hipRegisterFatBinary(&FatbinWrapper);
648 llvm::CallInst *RegisterFatbinCall = CtorBuilder.CreateCall(
650 CtorBuilder.CreateBitCast(FatbinWrapper, VoidPtrTy));
651 CtorBuilder.CreateStore(RegisterFatbinCall, GpuBinaryAddr);
652 CtorBuilder.CreateBr(ExitBlock);
655 CtorBuilder.SetInsertPoint(ExitBlock);
656 // Call __hip_register_globals(GpuBinaryHandle);
657 if (RegisterGlobalsFunc) {
658 auto HandleValue = CtorBuilder.CreateLoad(GpuBinaryAddr);
659 CtorBuilder.CreateCall(RegisterGlobalsFunc, HandleValue);
662 } else if (!RelocatableDeviceCode) {
663 // Register binary with CUDA runtime. This is substantially different in
664 // default mode vs. separate compilation!
665 // GpuBinaryHandle = __cudaRegisterFatBinary(&FatbinWrapper);
666 llvm::CallInst *RegisterFatbinCall = CtorBuilder.CreateCall(
668 CtorBuilder.CreateBitCast(FatbinWrapper, VoidPtrTy));
669 GpuBinaryHandle = new llvm::GlobalVariable(
670 TheModule, VoidPtrPtrTy, false, llvm::GlobalValue::InternalLinkage,
671 llvm::ConstantPointerNull::get(VoidPtrPtrTy), "__cuda_gpubin_handle");
672 GpuBinaryHandle->setAlignment(CGM.getPointerAlign().getAsAlign());
673 CtorBuilder.CreateAlignedStore(RegisterFatbinCall, GpuBinaryHandle,
674 CGM.getPointerAlign());
676 // Call __cuda_register_globals(GpuBinaryHandle);
677 if (RegisterGlobalsFunc)
678 CtorBuilder.CreateCall(RegisterGlobalsFunc, RegisterFatbinCall);
680 // Call __cudaRegisterFatBinaryEnd(Handle) if this CUDA version needs it.
681 if (CudaFeatureEnabled(CGM.getTarget().getSDKVersion(),
682 CudaFeature::CUDA_USES_FATBIN_REGISTER_END)) {
683 // void __cudaRegisterFatBinaryEnd(void **);
684 llvm::FunctionCallee RegisterFatbinEndFunc = CGM.CreateRuntimeFunction(
685 llvm::FunctionType::get(VoidTy, VoidPtrPtrTy, false),
686 "__cudaRegisterFatBinaryEnd");
687 CtorBuilder.CreateCall(RegisterFatbinEndFunc, RegisterFatbinCall);
690 // Generate a unique module ID.
691 SmallString<64> ModuleID;
692 llvm::raw_svector_ostream OS(ModuleID);
693 OS << ModuleIDPrefix << llvm::format("%" PRIx64, FatbinWrapper->getGUID());
694 llvm::Constant *ModuleIDConstant =
695 makeConstantString(ModuleID.str(), "", ModuleIDSectionName, 32);
697 // Create an alias for the FatbinWrapper that nvcc will look for.
698 llvm::GlobalAlias::create(llvm::GlobalValue::ExternalLinkage,
699 Twine("__fatbinwrap") + ModuleID, FatbinWrapper);
701 // void __cudaRegisterLinkedBinary%ModuleID%(void (*)(void *), void *,
702 // void *, void (*)(void **))
703 SmallString<128> RegisterLinkedBinaryName("__cudaRegisterLinkedBinary");
704 RegisterLinkedBinaryName += ModuleID;
705 llvm::FunctionCallee RegisterLinkedBinaryFunc = CGM.CreateRuntimeFunction(
706 getRegisterLinkedBinaryFnTy(), RegisterLinkedBinaryName);
708 assert(RegisterGlobalsFunc && "Expecting at least dummy function!");
709 llvm::Value *Args[] = {RegisterGlobalsFunc,
710 CtorBuilder.CreateBitCast(FatbinWrapper, VoidPtrTy),
712 makeDummyFunction(getCallbackFnTy())};
713 CtorBuilder.CreateCall(RegisterLinkedBinaryFunc, Args);
716 // Create destructor and register it with atexit() the way NVCC does it. Doing
717 // it during regular destructor phase worked in CUDA before 9.2 but results in
718 // double-free in 9.2.
719 if (llvm::Function *CleanupFn = makeModuleDtorFunction()) {
720 // extern "C" int atexit(void (*f)(void));
721 llvm::FunctionType *AtExitTy =
722 llvm::FunctionType::get(IntTy, CleanupFn->getType(), false);
723 llvm::FunctionCallee AtExitFunc =
724 CGM.CreateRuntimeFunction(AtExitTy, "atexit", llvm::AttributeList(),
726 CtorBuilder.CreateCall(AtExitFunc, CleanupFn);
729 CtorBuilder.CreateRetVoid();
730 return ModuleCtorFunc;
733 /// Creates a global destructor function that unregisters the GPU code blob
734 /// registered by constructor.
738 /// void __cuda_module_dtor(void*) {
739 /// __cudaUnregisterFatBinary(Handle);
745 /// void __hip_module_dtor(void*) {
746 /// if (__hip_gpubin_handle) {
747 /// __hipUnregisterFatBinary(__hip_gpubin_handle);
748 /// __hip_gpubin_handle = 0;
752 llvm::Function *CGNVCUDARuntime::makeModuleDtorFunction() {
753 // No need for destructor if we don't have a handle to unregister.
754 if (!GpuBinaryHandle)
757 // void __cudaUnregisterFatBinary(void ** handle);
758 llvm::FunctionCallee UnregisterFatbinFunc = CGM.CreateRuntimeFunction(
759 llvm::FunctionType::get(VoidTy, VoidPtrPtrTy, false),
760 addUnderscoredPrefixToName("UnregisterFatBinary"));
762 llvm::Function *ModuleDtorFunc = llvm::Function::Create(
763 llvm::FunctionType::get(VoidTy, VoidPtrTy, false),
764 llvm::GlobalValue::InternalLinkage,
765 addUnderscoredPrefixToName("_module_dtor"), &TheModule);
767 llvm::BasicBlock *DtorEntryBB =
768 llvm::BasicBlock::Create(Context, "entry", ModuleDtorFunc);
769 CGBuilderTy DtorBuilder(CGM, Context);
770 DtorBuilder.SetInsertPoint(DtorEntryBB);
772 Address GpuBinaryAddr(GpuBinaryHandle, CharUnits::fromQuantity(
773 GpuBinaryHandle->getAlignment()));
774 auto HandleValue = DtorBuilder.CreateLoad(GpuBinaryAddr);
775 // There is only one HIP fat binary per linked module, however there are
776 // multiple destructor functions. Make sure the fat binary is unregistered
778 if (CGM.getLangOpts().HIP) {
779 llvm::BasicBlock *IfBlock =
780 llvm::BasicBlock::Create(Context, "if", ModuleDtorFunc);
781 llvm::BasicBlock *ExitBlock =
782 llvm::BasicBlock::Create(Context, "exit", ModuleDtorFunc);
783 llvm::Constant *Zero = llvm::Constant::getNullValue(HandleValue->getType());
784 llvm::Value *NEZero = DtorBuilder.CreateICmpNE(HandleValue, Zero);
785 DtorBuilder.CreateCondBr(NEZero, IfBlock, ExitBlock);
787 DtorBuilder.SetInsertPoint(IfBlock);
788 DtorBuilder.CreateCall(UnregisterFatbinFunc, HandleValue);
789 DtorBuilder.CreateStore(Zero, GpuBinaryAddr);
790 DtorBuilder.CreateBr(ExitBlock);
792 DtorBuilder.SetInsertPoint(ExitBlock);
794 DtorBuilder.CreateCall(UnregisterFatbinFunc, HandleValue);
796 DtorBuilder.CreateRetVoid();
797 return ModuleDtorFunc;
800 std::string CGNVCUDARuntime::getDeviceStubName(llvm::StringRef Name) const {
801 if (!CGM.getLangOpts().HIP)
803 return (Name + ".stub").str();
806 CGCUDARuntime *CodeGen::CreateNVCUDARuntime(CodeGenModule &CGM) {
807 return new CGNVCUDARuntime(CGM);