forked from OSchip/llvm-project
320 lines
13 KiB
C++
320 lines
13 KiB
C++
//===----- CGCUDANV.cpp - Interface to NVIDIA CUDA Runtime ----------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This provides a class for CUDA code generation targeting the NVIDIA CUDA
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// runtime library.
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//
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//===----------------------------------------------------------------------===//
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#include "CGCUDARuntime.h"
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#include "CodeGenFunction.h"
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#include "CodeGenModule.h"
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#include "clang/AST/Decl.h"
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#include "llvm/IR/BasicBlock.h"
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#include "llvm/IR/CallSite.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DerivedTypes.h"
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using namespace clang;
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using namespace CodeGen;
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namespace {
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class CGNVCUDARuntime : public CGCUDARuntime {
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private:
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llvm::Type *IntTy, *SizeTy, *VoidTy;
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llvm::PointerType *CharPtrTy, *VoidPtrTy, *VoidPtrPtrTy;
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/// Convenience reference to LLVM Context
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llvm::LLVMContext &Context;
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/// Convenience reference to the current module
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llvm::Module &TheModule;
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/// Keeps track of kernel launch stubs emitted in this module
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llvm::SmallVector<llvm::Function *, 16> EmittedKernels;
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/// Keeps track of variables containing handles of GPU binaries. Populated by
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/// ModuleCtorFunction() and used to create corresponding cleanup calls in
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/// ModuleDtorFunction()
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llvm::SmallVector<llvm::GlobalVariable *, 16> GpuBinaryHandles;
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llvm::Constant *getSetupArgumentFn() const;
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llvm::Constant *getLaunchFn() const;
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/// Creates a function to register all kernel stubs generated in this module.
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llvm::Function *makeRegisterKernelsFn();
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/// Helper function that generates a constant string and returns a pointer to
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/// the start of the string. The result of this function can be used anywhere
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/// where the C code specifies const char*.
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llvm::Constant *makeConstantString(const std::string &Str,
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const std::string &Name = "",
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unsigned Alignment = 0) {
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llvm::Constant *Zeros[] = {llvm::ConstantInt::get(SizeTy, 0),
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llvm::ConstantInt::get(SizeTy, 0)};
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auto ConstStr = CGM.GetAddrOfConstantCString(Str, Name.c_str());
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return llvm::ConstantExpr::getGetElementPtr(ConstStr.getElementType(),
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ConstStr.getPointer(), Zeros);
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}
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void emitDeviceStubBody(CodeGenFunction &CGF, FunctionArgList &Args);
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public:
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CGNVCUDARuntime(CodeGenModule &CGM);
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void emitDeviceStub(CodeGenFunction &CGF, FunctionArgList &Args) override;
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/// Creates module constructor function
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llvm::Function *makeModuleCtorFunction() override;
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/// Creates module destructor function
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llvm::Function *makeModuleDtorFunction() override;
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};
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}
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CGNVCUDARuntime::CGNVCUDARuntime(CodeGenModule &CGM)
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: CGCUDARuntime(CGM), Context(CGM.getLLVMContext()),
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TheModule(CGM.getModule()) {
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CodeGen::CodeGenTypes &Types = CGM.getTypes();
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ASTContext &Ctx = CGM.getContext();
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IntTy = Types.ConvertType(Ctx.IntTy);
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SizeTy = Types.ConvertType(Ctx.getSizeType());
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VoidTy = llvm::Type::getVoidTy(Context);
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CharPtrTy = llvm::PointerType::getUnqual(Types.ConvertType(Ctx.CharTy));
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VoidPtrTy = cast<llvm::PointerType>(Types.ConvertType(Ctx.VoidPtrTy));
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VoidPtrPtrTy = VoidPtrTy->getPointerTo();
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}
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llvm::Constant *CGNVCUDARuntime::getSetupArgumentFn() const {
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// cudaError_t cudaSetupArgument(void *, size_t, size_t)
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std::vector<llvm::Type*> Params;
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Params.push_back(VoidPtrTy);
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Params.push_back(SizeTy);
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Params.push_back(SizeTy);
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return CGM.CreateRuntimeFunction(llvm::FunctionType::get(IntTy,
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Params, false),
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"cudaSetupArgument");
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}
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llvm::Constant *CGNVCUDARuntime::getLaunchFn() const {
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// cudaError_t cudaLaunch(char *)
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return CGM.CreateRuntimeFunction(
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llvm::FunctionType::get(IntTy, CharPtrTy, false), "cudaLaunch");
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}
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void CGNVCUDARuntime::emitDeviceStub(CodeGenFunction &CGF,
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FunctionArgList &Args) {
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EmittedKernels.push_back(CGF.CurFn);
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emitDeviceStubBody(CGF, Args);
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}
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void CGNVCUDARuntime::emitDeviceStubBody(CodeGenFunction &CGF,
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FunctionArgList &Args) {
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// Build the argument value list and the argument stack struct type.
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SmallVector<llvm::Value *, 16> ArgValues;
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std::vector<llvm::Type *> ArgTypes;
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for (FunctionArgList::const_iterator I = Args.begin(), E = Args.end();
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I != E; ++I) {
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llvm::Value *V = CGF.GetAddrOfLocalVar(*I).getPointer();
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ArgValues.push_back(V);
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assert(isa<llvm::PointerType>(V->getType()) && "Arg type not PointerType");
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ArgTypes.push_back(cast<llvm::PointerType>(V->getType())->getElementType());
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}
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llvm::StructType *ArgStackTy = llvm::StructType::get(Context, ArgTypes);
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llvm::BasicBlock *EndBlock = CGF.createBasicBlock("setup.end");
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// Emit the calls to cudaSetupArgument
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llvm::Constant *cudaSetupArgFn = getSetupArgumentFn();
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for (unsigned I = 0, E = Args.size(); I != E; ++I) {
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llvm::Value *Args[3];
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llvm::BasicBlock *NextBlock = CGF.createBasicBlock("setup.next");
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Args[0] = CGF.Builder.CreatePointerCast(ArgValues[I], VoidPtrTy);
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Args[1] = CGF.Builder.CreateIntCast(
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llvm::ConstantExpr::getSizeOf(ArgTypes[I]),
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SizeTy, false);
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Args[2] = CGF.Builder.CreateIntCast(
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llvm::ConstantExpr::getOffsetOf(ArgStackTy, I),
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SizeTy, false);
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llvm::CallSite CS = CGF.EmitRuntimeCallOrInvoke(cudaSetupArgFn, Args);
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llvm::Constant *Zero = llvm::ConstantInt::get(IntTy, 0);
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llvm::Value *CSZero = CGF.Builder.CreateICmpEQ(CS.getInstruction(), Zero);
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CGF.Builder.CreateCondBr(CSZero, NextBlock, EndBlock);
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CGF.EmitBlock(NextBlock);
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}
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// Emit the call to cudaLaunch
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llvm::Constant *cudaLaunchFn = getLaunchFn();
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llvm::Value *Arg = CGF.Builder.CreatePointerCast(CGF.CurFn, CharPtrTy);
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CGF.EmitRuntimeCallOrInvoke(cudaLaunchFn, Arg);
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CGF.EmitBranch(EndBlock);
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CGF.EmitBlock(EndBlock);
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}
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/// Creates internal function to register all kernel stubs generated in this
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/// module with the CUDA runtime.
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/// \code
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/// void __cuda_register_kernels(void** GpuBinaryHandle) {
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/// __cudaRegisterFunction(GpuBinaryHandle,Kernel0,...);
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/// ...
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/// __cudaRegisterFunction(GpuBinaryHandle,KernelM,...);
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/// }
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/// \endcode
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llvm::Function *CGNVCUDARuntime::makeRegisterKernelsFn() {
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llvm::Function *RegisterKernelsFunc = llvm::Function::Create(
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llvm::FunctionType::get(VoidTy, VoidPtrPtrTy, false),
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llvm::GlobalValue::InternalLinkage, "__cuda_register_kernels", &TheModule);
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llvm::BasicBlock *EntryBB =
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llvm::BasicBlock::Create(Context, "entry", RegisterKernelsFunc);
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CGBuilderTy Builder(CGM, Context);
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Builder.SetInsertPoint(EntryBB);
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// void __cudaRegisterFunction(void **, const char *, char *, const char *,
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// int, uint3*, uint3*, dim3*, dim3*, int*)
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std::vector<llvm::Type *> RegisterFuncParams = {
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VoidPtrPtrTy, CharPtrTy, CharPtrTy, CharPtrTy, IntTy,
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VoidPtrTy, VoidPtrTy, VoidPtrTy, VoidPtrTy, IntTy->getPointerTo()};
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llvm::Constant *RegisterFunc = CGM.CreateRuntimeFunction(
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llvm::FunctionType::get(IntTy, RegisterFuncParams, false),
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"__cudaRegisterFunction");
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// Extract GpuBinaryHandle passed as the first argument passed to
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// __cuda_register_kernels() and generate __cudaRegisterFunction() call for
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// each emitted kernel.
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llvm::Argument &GpuBinaryHandlePtr = *RegisterKernelsFunc->arg_begin();
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for (llvm::Function *Kernel : EmittedKernels) {
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llvm::Constant *KernelName = makeConstantString(Kernel->getName());
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llvm::Constant *NullPtr = llvm::ConstantPointerNull::get(VoidPtrTy);
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llvm::Value *args[] = {
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&GpuBinaryHandlePtr, Builder.CreateBitCast(Kernel, VoidPtrTy),
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KernelName, KernelName, llvm::ConstantInt::get(IntTy, -1), NullPtr,
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NullPtr, NullPtr, NullPtr,
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llvm::ConstantPointerNull::get(IntTy->getPointerTo())};
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Builder.CreateCall(RegisterFunc, args);
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}
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Builder.CreateRetVoid();
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return RegisterKernelsFunc;
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}
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/// Creates a global constructor function for the module:
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/// \code
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/// void __cuda_module_ctor(void*) {
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/// Handle0 = __cudaRegisterFatBinary(GpuBinaryBlob0);
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/// __cuda_register_kernels(Handle0);
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/// ...
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/// HandleN = __cudaRegisterFatBinary(GpuBinaryBlobN);
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/// __cuda_register_kernels(HandleN);
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/// }
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/// \endcode
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llvm::Function *CGNVCUDARuntime::makeModuleCtorFunction() {
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// void __cuda_register_kernels(void* handle);
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llvm::Function *RegisterKernelsFunc = makeRegisterKernelsFn();
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// void ** __cudaRegisterFatBinary(void *);
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llvm::Constant *RegisterFatbinFunc = CGM.CreateRuntimeFunction(
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llvm::FunctionType::get(VoidPtrPtrTy, VoidPtrTy, false),
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"__cudaRegisterFatBinary");
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// struct { int magic, int version, void * gpu_binary, void * dont_care };
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llvm::StructType *FatbinWrapperTy =
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llvm::StructType::get(IntTy, IntTy, VoidPtrTy, VoidPtrTy, nullptr);
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llvm::Function *ModuleCtorFunc = llvm::Function::Create(
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llvm::FunctionType::get(VoidTy, VoidPtrTy, false),
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llvm::GlobalValue::InternalLinkage, "__cuda_module_ctor", &TheModule);
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llvm::BasicBlock *CtorEntryBB =
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llvm::BasicBlock::Create(Context, "entry", ModuleCtorFunc);
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CGBuilderTy CtorBuilder(CGM, Context);
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CtorBuilder.SetInsertPoint(CtorEntryBB);
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// For each GPU binary, register it with the CUDA runtime and store returned
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// handle in a global variable and save the handle in GpuBinaryHandles vector
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// to be cleaned up in destructor on exit. Then associate all known kernels
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// with the GPU binary handle so CUDA runtime can figure out what to call on
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// the GPU side.
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for (const std::string &GpuBinaryFileName :
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CGM.getCodeGenOpts().CudaGpuBinaryFileNames) {
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llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> GpuBinaryOrErr =
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llvm::MemoryBuffer::getFileOrSTDIN(GpuBinaryFileName);
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if (std::error_code EC = GpuBinaryOrErr.getError()) {
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CGM.getDiags().Report(diag::err_cannot_open_file) << GpuBinaryFileName
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<< EC.message();
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continue;
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}
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// Create initialized wrapper structure that points to the loaded GPU binary
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llvm::Constant *Values[] = {
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llvm::ConstantInt::get(IntTy, 0x466243b1), // Fatbin wrapper magic.
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llvm::ConstantInt::get(IntTy, 1), // Fatbin version.
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makeConstantString(GpuBinaryOrErr.get()->getBuffer(), "", 16), // Data.
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llvm::ConstantPointerNull::get(VoidPtrTy)}; // Unused in fatbin v1.
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llvm::GlobalVariable *FatbinWrapper = new llvm::GlobalVariable(
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TheModule, FatbinWrapperTy, true, llvm::GlobalValue::InternalLinkage,
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llvm::ConstantStruct::get(FatbinWrapperTy, Values),
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"__cuda_fatbin_wrapper");
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// GpuBinaryHandle = __cudaRegisterFatBinary(&FatbinWrapper);
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llvm::CallInst *RegisterFatbinCall = CtorBuilder.CreateCall(
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RegisterFatbinFunc,
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CtorBuilder.CreateBitCast(FatbinWrapper, VoidPtrTy));
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llvm::GlobalVariable *GpuBinaryHandle = new llvm::GlobalVariable(
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TheModule, VoidPtrPtrTy, false, llvm::GlobalValue::InternalLinkage,
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llvm::ConstantPointerNull::get(VoidPtrPtrTy), "__cuda_gpubin_handle");
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CtorBuilder.CreateAlignedStore(RegisterFatbinCall, GpuBinaryHandle,
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CGM.getPointerAlign());
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// Call __cuda_register_kernels(GpuBinaryHandle);
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CtorBuilder.CreateCall(RegisterKernelsFunc, RegisterFatbinCall);
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// Save GpuBinaryHandle so we can unregister it in destructor.
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GpuBinaryHandles.push_back(GpuBinaryHandle);
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}
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CtorBuilder.CreateRetVoid();
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return ModuleCtorFunc;
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}
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/// Creates a global destructor function that unregisters all GPU code blobs
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/// registered by constructor.
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/// \code
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/// void __cuda_module_dtor(void*) {
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/// __cudaUnregisterFatBinary(Handle0);
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/// ...
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/// __cudaUnregisterFatBinary(HandleN);
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/// }
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/// \endcode
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llvm::Function *CGNVCUDARuntime::makeModuleDtorFunction() {
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// void __cudaUnregisterFatBinary(void ** handle);
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llvm::Constant *UnregisterFatbinFunc = CGM.CreateRuntimeFunction(
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llvm::FunctionType::get(VoidTy, VoidPtrPtrTy, false),
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"__cudaUnregisterFatBinary");
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llvm::Function *ModuleDtorFunc = llvm::Function::Create(
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llvm::FunctionType::get(VoidTy, VoidPtrTy, false),
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llvm::GlobalValue::InternalLinkage, "__cuda_module_dtor", &TheModule);
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llvm::BasicBlock *DtorEntryBB =
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llvm::BasicBlock::Create(Context, "entry", ModuleDtorFunc);
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CGBuilderTy DtorBuilder(CGM, Context);
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DtorBuilder.SetInsertPoint(DtorEntryBB);
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for (llvm::GlobalVariable *GpuBinaryHandle : GpuBinaryHandles) {
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auto HandleValue =
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DtorBuilder.CreateAlignedLoad(GpuBinaryHandle, CGM.getPointerAlign());
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DtorBuilder.CreateCall(UnregisterFatbinFunc, HandleValue);
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}
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DtorBuilder.CreateRetVoid();
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return ModuleDtorFunc;
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}
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CGCUDARuntime *CodeGen::CreateNVCUDARuntime(CodeGenModule &CGM) {
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return new CGNVCUDARuntime(CGM);
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}
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