1 //===----- CGCUDANV.cpp - Interface to NVIDIA CUDA Runtime ----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This provides a class for CUDA code generation targeting the NVIDIA CUDA
13 //===----------------------------------------------------------------------===//
15 #include "CGCUDARuntime.h"
16 #include "CodeGenFunction.h"
17 #include "CodeGenModule.h"
18 #include "clang/AST/Decl.h"
19 #include "llvm/IR/BasicBlock.h"
20 #include "llvm/IR/CallSite.h"
21 #include "llvm/IR/Constants.h"
22 #include "llvm/IR/DerivedTypes.h"
24 using namespace clang;
25 using namespace CodeGen;
29 class CGNVCUDARuntime : public CGCUDARuntime {
32 llvm::Type *IntTy, *SizeTy, *VoidTy;
33 llvm::PointerType *CharPtrTy, *VoidPtrTy, *VoidPtrPtrTy;
35 /// Convenience reference to LLVM Context
36 llvm::LLVMContext &Context;
37 /// Convenience reference to the current module
38 llvm::Module &TheModule;
39 /// Keeps track of kernel launch stubs emitted in this module
40 llvm::SmallVector<llvm::Function *, 16> EmittedKernels;
41 llvm::SmallVector<std::pair<llvm::GlobalVariable *, unsigned>, 16> DeviceVars;
42 /// Keeps track of variables containing handles of GPU binaries. Populated by
43 /// ModuleCtorFunction() and used to create corresponding cleanup calls in
44 /// ModuleDtorFunction()
45 llvm::SmallVector<llvm::GlobalVariable *, 16> GpuBinaryHandles;
47 llvm::Constant *getSetupArgumentFn() const;
48 llvm::Constant *getLaunchFn() const;
50 /// Creates a function to register all kernel stubs generated in this module.
51 llvm::Function *makeRegisterGlobalsFn();
53 /// Helper function that generates a constant string and returns a pointer to
54 /// the start of the string. The result of this function can be used anywhere
55 /// where the C code specifies const char*.
56 llvm::Constant *makeConstantString(const std::string &Str,
57 const std::string &Name = "",
58 unsigned Alignment = 0) {
59 llvm::Constant *Zeros[] = {llvm::ConstantInt::get(SizeTy, 0),
60 llvm::ConstantInt::get(SizeTy, 0)};
61 auto ConstStr = CGM.GetAddrOfConstantCString(Str, Name.c_str());
62 return llvm::ConstantExpr::getGetElementPtr(ConstStr.getElementType(),
63 ConstStr.getPointer(), Zeros);
66 void emitDeviceStubBody(CodeGenFunction &CGF, FunctionArgList &Args);
69 CGNVCUDARuntime(CodeGenModule &CGM);
71 void emitDeviceStub(CodeGenFunction &CGF, FunctionArgList &Args) override;
72 void registerDeviceVar(llvm::GlobalVariable &Var, unsigned Flags) override {
73 DeviceVars.push_back(std::make_pair(&Var, Flags));
76 /// Creates module constructor function
77 llvm::Function *makeModuleCtorFunction() override;
78 /// Creates module destructor function
79 llvm::Function *makeModuleDtorFunction() override;
84 CGNVCUDARuntime::CGNVCUDARuntime(CodeGenModule &CGM)
85 : CGCUDARuntime(CGM), Context(CGM.getLLVMContext()),
86 TheModule(CGM.getModule()) {
87 CodeGen::CodeGenTypes &Types = CGM.getTypes();
88 ASTContext &Ctx = CGM.getContext();
90 IntTy = Types.ConvertType(Ctx.IntTy);
91 SizeTy = Types.ConvertType(Ctx.getSizeType());
92 VoidTy = llvm::Type::getVoidTy(Context);
94 CharPtrTy = llvm::PointerType::getUnqual(Types.ConvertType(Ctx.CharTy));
95 VoidPtrTy = cast<llvm::PointerType>(Types.ConvertType(Ctx.VoidPtrTy));
96 VoidPtrPtrTy = VoidPtrTy->getPointerTo();
99 llvm::Constant *CGNVCUDARuntime::getSetupArgumentFn() const {
100 // cudaError_t cudaSetupArgument(void *, size_t, size_t)
101 llvm::Type *Params[] = {VoidPtrTy, SizeTy, SizeTy};
102 return CGM.CreateRuntimeFunction(llvm::FunctionType::get(IntTy,
104 "cudaSetupArgument");
107 llvm::Constant *CGNVCUDARuntime::getLaunchFn() const {
108 // cudaError_t cudaLaunch(char *)
109 return CGM.CreateRuntimeFunction(
110 llvm::FunctionType::get(IntTy, CharPtrTy, false), "cudaLaunch");
113 void CGNVCUDARuntime::emitDeviceStub(CodeGenFunction &CGF,
114 FunctionArgList &Args) {
115 EmittedKernels.push_back(CGF.CurFn);
116 emitDeviceStubBody(CGF, Args);
119 void CGNVCUDARuntime::emitDeviceStubBody(CodeGenFunction &CGF,
120 FunctionArgList &Args) {
121 // Build the argument value list and the argument stack struct type.
122 SmallVector<llvm::Value *, 16> ArgValues;
123 std::vector<llvm::Type *> ArgTypes;
124 for (FunctionArgList::const_iterator I = Args.begin(), E = Args.end();
126 llvm::Value *V = CGF.GetAddrOfLocalVar(*I).getPointer();
127 ArgValues.push_back(V);
128 assert(isa<llvm::PointerType>(V->getType()) && "Arg type not PointerType");
129 ArgTypes.push_back(cast<llvm::PointerType>(V->getType())->getElementType());
131 llvm::StructType *ArgStackTy = llvm::StructType::get(Context, ArgTypes);
133 llvm::BasicBlock *EndBlock = CGF.createBasicBlock("setup.end");
135 // Emit the calls to cudaSetupArgument
136 llvm::Constant *cudaSetupArgFn = getSetupArgumentFn();
137 for (unsigned I = 0, E = Args.size(); I != E; ++I) {
138 llvm::Value *Args[3];
139 llvm::BasicBlock *NextBlock = CGF.createBasicBlock("setup.next");
140 Args[0] = CGF.Builder.CreatePointerCast(ArgValues[I], VoidPtrTy);
141 Args[1] = CGF.Builder.CreateIntCast(
142 llvm::ConstantExpr::getSizeOf(ArgTypes[I]),
144 Args[2] = CGF.Builder.CreateIntCast(
145 llvm::ConstantExpr::getOffsetOf(ArgStackTy, I),
147 llvm::CallSite CS = CGF.EmitRuntimeCallOrInvoke(cudaSetupArgFn, Args);
148 llvm::Constant *Zero = llvm::ConstantInt::get(IntTy, 0);
149 llvm::Value *CSZero = CGF.Builder.CreateICmpEQ(CS.getInstruction(), Zero);
150 CGF.Builder.CreateCondBr(CSZero, NextBlock, EndBlock);
151 CGF.EmitBlock(NextBlock);
154 // Emit the call to cudaLaunch
155 llvm::Constant *cudaLaunchFn = getLaunchFn();
156 llvm::Value *Arg = CGF.Builder.CreatePointerCast(CGF.CurFn, CharPtrTy);
157 CGF.EmitRuntimeCallOrInvoke(cudaLaunchFn, Arg);
158 CGF.EmitBranch(EndBlock);
160 CGF.EmitBlock(EndBlock);
163 /// Creates a function that sets up state on the host side for CUDA objects that
164 /// have a presence on both the host and device sides. Specifically, registers
165 /// the host side of kernel functions and device global variables with the CUDA
168 /// void __cuda_register_globals(void** GpuBinaryHandle) {
169 /// __cudaRegisterFunction(GpuBinaryHandle,Kernel0,...);
171 /// __cudaRegisterFunction(GpuBinaryHandle,KernelM,...);
172 /// __cudaRegisterVar(GpuBinaryHandle, GlobalVar0, ...);
174 /// __cudaRegisterVar(GpuBinaryHandle, GlobalVarN, ...);
177 llvm::Function *CGNVCUDARuntime::makeRegisterGlobalsFn() {
178 // No need to register anything
179 if (EmittedKernels.empty() && DeviceVars.empty())
182 llvm::Function *RegisterKernelsFunc = llvm::Function::Create(
183 llvm::FunctionType::get(VoidTy, VoidPtrPtrTy, false),
184 llvm::GlobalValue::InternalLinkage, "__cuda_register_globals", &TheModule);
185 llvm::BasicBlock *EntryBB =
186 llvm::BasicBlock::Create(Context, "entry", RegisterKernelsFunc);
187 CGBuilderTy Builder(CGM, Context);
188 Builder.SetInsertPoint(EntryBB);
190 // void __cudaRegisterFunction(void **, const char *, char *, const char *,
191 // int, uint3*, uint3*, dim3*, dim3*, int*)
192 llvm::Type *RegisterFuncParams[] = {
193 VoidPtrPtrTy, CharPtrTy, CharPtrTy, CharPtrTy, IntTy,
194 VoidPtrTy, VoidPtrTy, VoidPtrTy, VoidPtrTy, IntTy->getPointerTo()};
195 llvm::Constant *RegisterFunc = CGM.CreateRuntimeFunction(
196 llvm::FunctionType::get(IntTy, RegisterFuncParams, false),
197 "__cudaRegisterFunction");
199 // Extract GpuBinaryHandle passed as the first argument passed to
200 // __cuda_register_globals() and generate __cudaRegisterFunction() call for
201 // each emitted kernel.
202 llvm::Argument &GpuBinaryHandlePtr = *RegisterKernelsFunc->arg_begin();
203 for (llvm::Function *Kernel : EmittedKernels) {
204 llvm::Constant *KernelName = makeConstantString(Kernel->getName());
205 llvm::Constant *NullPtr = llvm::ConstantPointerNull::get(VoidPtrTy);
206 llvm::Value *Args[] = {
207 &GpuBinaryHandlePtr, Builder.CreateBitCast(Kernel, VoidPtrTy),
208 KernelName, KernelName, llvm::ConstantInt::get(IntTy, -1), NullPtr,
209 NullPtr, NullPtr, NullPtr,
210 llvm::ConstantPointerNull::get(IntTy->getPointerTo())};
211 Builder.CreateCall(RegisterFunc, Args);
214 // void __cudaRegisterVar(void **, char *, char *, const char *,
215 // int, int, int, int)
216 llvm::Type *RegisterVarParams[] = {VoidPtrPtrTy, CharPtrTy, CharPtrTy,
217 CharPtrTy, IntTy, IntTy,
219 llvm::Constant *RegisterVar = CGM.CreateRuntimeFunction(
220 llvm::FunctionType::get(IntTy, RegisterVarParams, false),
221 "__cudaRegisterVar");
222 for (auto &Pair : DeviceVars) {
223 llvm::GlobalVariable *Var = Pair.first;
224 unsigned Flags = Pair.second;
225 llvm::Constant *VarName = makeConstantString(Var->getName());
227 CGM.getDataLayout().getTypeAllocSize(Var->getValueType());
228 llvm::Value *Args[] = {
230 Builder.CreateBitCast(Var, VoidPtrTy),
233 llvm::ConstantInt::get(IntTy, (Flags & ExternDeviceVar) ? 1 : 0),
234 llvm::ConstantInt::get(IntTy, VarSize),
235 llvm::ConstantInt::get(IntTy, (Flags & ConstantDeviceVar) ? 1 : 0),
236 llvm::ConstantInt::get(IntTy, 0)};
237 Builder.CreateCall(RegisterVar, Args);
240 Builder.CreateRetVoid();
241 return RegisterKernelsFunc;
244 /// Creates a global constructor function for the module:
246 /// void __cuda_module_ctor(void*) {
247 /// Handle0 = __cudaRegisterFatBinary(GpuBinaryBlob0);
248 /// __cuda_register_globals(Handle0);
250 /// HandleN = __cudaRegisterFatBinary(GpuBinaryBlobN);
251 /// __cuda_register_globals(HandleN);
254 llvm::Function *CGNVCUDARuntime::makeModuleCtorFunction() {
255 // No need to generate ctors/dtors if there are no GPU binaries.
256 if (CGM.getCodeGenOpts().CudaGpuBinaryFileNames.empty())
259 // void __cuda_register_globals(void* handle);
260 llvm::Function *RegisterGlobalsFunc = makeRegisterGlobalsFn();
261 // void ** __cudaRegisterFatBinary(void *);
262 llvm::Constant *RegisterFatbinFunc = CGM.CreateRuntimeFunction(
263 llvm::FunctionType::get(VoidPtrPtrTy, VoidPtrTy, false),
264 "__cudaRegisterFatBinary");
265 // struct { int magic, int version, void * gpu_binary, void * dont_care };
266 llvm::StructType *FatbinWrapperTy =
267 llvm::StructType::get(IntTy, IntTy, VoidPtrTy, VoidPtrTy, nullptr);
269 llvm::Function *ModuleCtorFunc = llvm::Function::Create(
270 llvm::FunctionType::get(VoidTy, VoidPtrTy, false),
271 llvm::GlobalValue::InternalLinkage, "__cuda_module_ctor", &TheModule);
272 llvm::BasicBlock *CtorEntryBB =
273 llvm::BasicBlock::Create(Context, "entry", ModuleCtorFunc);
274 CGBuilderTy CtorBuilder(CGM, Context);
276 CtorBuilder.SetInsertPoint(CtorEntryBB);
278 // For each GPU binary, register it with the CUDA runtime and store returned
279 // handle in a global variable and save the handle in GpuBinaryHandles vector
280 // to be cleaned up in destructor on exit. Then associate all known kernels
281 // with the GPU binary handle so CUDA runtime can figure out what to call on
283 for (const std::string &GpuBinaryFileName :
284 CGM.getCodeGenOpts().CudaGpuBinaryFileNames) {
285 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> GpuBinaryOrErr =
286 llvm::MemoryBuffer::getFileOrSTDIN(GpuBinaryFileName);
287 if (std::error_code EC = GpuBinaryOrErr.getError()) {
288 CGM.getDiags().Report(diag::err_cannot_open_file) << GpuBinaryFileName
293 // Create initialized wrapper structure that points to the loaded GPU binary
294 llvm::Constant *Values[] = {
295 llvm::ConstantInt::get(IntTy, 0x466243b1), // Fatbin wrapper magic.
296 llvm::ConstantInt::get(IntTy, 1), // Fatbin version.
297 makeConstantString(GpuBinaryOrErr.get()->getBuffer(), "", 16), // Data.
298 llvm::ConstantPointerNull::get(VoidPtrTy)}; // Unused in fatbin v1.
299 llvm::GlobalVariable *FatbinWrapper = new llvm::GlobalVariable(
300 TheModule, FatbinWrapperTy, true, llvm::GlobalValue::InternalLinkage,
301 llvm::ConstantStruct::get(FatbinWrapperTy, Values),
302 "__cuda_fatbin_wrapper");
303 // NVIDIA's cuobjdump looks for fatbins in this section.
304 FatbinWrapper->setSection(".nvFatBinSegment");
306 // GpuBinaryHandle = __cudaRegisterFatBinary(&FatbinWrapper);
307 llvm::CallInst *RegisterFatbinCall = CtorBuilder.CreateCall(
309 CtorBuilder.CreateBitCast(FatbinWrapper, VoidPtrTy));
310 llvm::GlobalVariable *GpuBinaryHandle = new llvm::GlobalVariable(
311 TheModule, VoidPtrPtrTy, false, llvm::GlobalValue::InternalLinkage,
312 llvm::ConstantPointerNull::get(VoidPtrPtrTy), "__cuda_gpubin_handle");
313 CtorBuilder.CreateAlignedStore(RegisterFatbinCall, GpuBinaryHandle,
314 CGM.getPointerAlign());
316 // Call __cuda_register_globals(GpuBinaryHandle);
317 if (RegisterGlobalsFunc)
318 CtorBuilder.CreateCall(RegisterGlobalsFunc, RegisterFatbinCall);
320 // Save GpuBinaryHandle so we can unregister it in destructor.
321 GpuBinaryHandles.push_back(GpuBinaryHandle);
324 CtorBuilder.CreateRetVoid();
325 return ModuleCtorFunc;
328 /// Creates a global destructor function that unregisters all GPU code blobs
329 /// registered by constructor.
331 /// void __cuda_module_dtor(void*) {
332 /// __cudaUnregisterFatBinary(Handle0);
334 /// __cudaUnregisterFatBinary(HandleN);
337 llvm::Function *CGNVCUDARuntime::makeModuleDtorFunction() {
338 // No need for destructor if we don't have handles to unregister.
339 if (GpuBinaryHandles.empty())
342 // void __cudaUnregisterFatBinary(void ** handle);
343 llvm::Constant *UnregisterFatbinFunc = CGM.CreateRuntimeFunction(
344 llvm::FunctionType::get(VoidTy, VoidPtrPtrTy, false),
345 "__cudaUnregisterFatBinary");
347 llvm::Function *ModuleDtorFunc = llvm::Function::Create(
348 llvm::FunctionType::get(VoidTy, VoidPtrTy, false),
349 llvm::GlobalValue::InternalLinkage, "__cuda_module_dtor", &TheModule);
350 llvm::BasicBlock *DtorEntryBB =
351 llvm::BasicBlock::Create(Context, "entry", ModuleDtorFunc);
352 CGBuilderTy DtorBuilder(CGM, Context);
353 DtorBuilder.SetInsertPoint(DtorEntryBB);
355 for (llvm::GlobalVariable *GpuBinaryHandle : GpuBinaryHandles) {
357 DtorBuilder.CreateAlignedLoad(GpuBinaryHandle, CGM.getPointerAlign());
358 DtorBuilder.CreateCall(UnregisterFatbinFunc, HandleValue);
361 DtorBuilder.CreateRetVoid();
362 return ModuleDtorFunc;
365 CGCUDARuntime *CodeGen::CreateNVCUDARuntime(CodeGenModule &CGM) {
366 return new CGNVCUDARuntime(CGM);