clang  3.9.0
CGCUDANV.cpp
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1 //===----- CGCUDANV.cpp - Interface to NVIDIA CUDA Runtime ----------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This provides a class for CUDA code generation targeting the NVIDIA CUDA
11 // runtime library.
12 //
13 //===----------------------------------------------------------------------===//
14 
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"
23 
24 using namespace clang;
25 using namespace CodeGen;
26 
27 namespace {
28 
29 class CGNVCUDARuntime : public CGCUDARuntime {
30 
31 private:
32  llvm::Type *IntTy, *SizeTy, *VoidTy;
33  llvm::PointerType *CharPtrTy, *VoidPtrTy, *VoidPtrPtrTy;
34 
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
42  /// Keeps track of variables containing handles of GPU binaries. Populated by
43  /// ModuleCtorFunction() and used to create corresponding cleanup calls in
44  /// ModuleDtorFunction()
46 
47  llvm::Constant *getSetupArgumentFn() const;
48  llvm::Constant *getLaunchFn() const;
49 
50  /// Creates a function to register all kernel stubs generated in this module.
51  llvm::Function *makeRegisterGlobalsFn();
52 
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);
64  }
65 
66  void emitDeviceStubBody(CodeGenFunction &CGF, FunctionArgList &Args);
67 
68 public:
69  CGNVCUDARuntime(CodeGenModule &CGM);
70 
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));
74  }
75 
76  /// Creates module constructor function
77  llvm::Function *makeModuleCtorFunction() override;
78  /// Creates module destructor function
79  llvm::Function *makeModuleDtorFunction() override;
80 };
81 
82 }
83 
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();
89 
90  IntTy = Types.ConvertType(Ctx.IntTy);
91  SizeTy = Types.ConvertType(Ctx.getSizeType());
92  VoidTy = llvm::Type::getVoidTy(Context);
93 
94  CharPtrTy = llvm::PointerType::getUnqual(Types.ConvertType(Ctx.CharTy));
95  VoidPtrTy = cast<llvm::PointerType>(Types.ConvertType(Ctx.VoidPtrTy));
96  VoidPtrPtrTy = VoidPtrTy->getPointerTo();
97 }
98 
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,
103  Params, false),
104  "cudaSetupArgument");
105 }
106 
107 llvm::Constant *CGNVCUDARuntime::getLaunchFn() const {
108  // cudaError_t cudaLaunch(char *)
109  return CGM.CreateRuntimeFunction(
110  llvm::FunctionType::get(IntTy, CharPtrTy, false), "cudaLaunch");
111 }
112 
113 void CGNVCUDARuntime::emitDeviceStub(CodeGenFunction &CGF,
114  FunctionArgList &Args) {
115  EmittedKernels.push_back(CGF.CurFn);
116  emitDeviceStubBody(CGF, Args);
117 }
118 
119 void CGNVCUDARuntime::emitDeviceStubBody(CodeGenFunction &CGF,
120  FunctionArgList &Args) {
121  // Build the argument value list and the argument stack struct type.
123  std::vector<llvm::Type *> ArgTypes;
124  for (FunctionArgList::const_iterator I = Args.begin(), E = Args.end();
125  I != E; ++I) {
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());
130  }
131  llvm::StructType *ArgStackTy = llvm::StructType::get(Context, ArgTypes);
132 
133  llvm::BasicBlock *EndBlock = CGF.createBasicBlock("setup.end");
134 
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]),
143  SizeTy, false);
144  Args[2] = CGF.Builder.CreateIntCast(
145  llvm::ConstantExpr::getOffsetOf(ArgStackTy, I),
146  SizeTy, false);
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);
152  }
153 
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);
159 
160  CGF.EmitBlock(EndBlock);
161 }
162 
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
166 /// runtime.
167 /// \code
168 /// void __cuda_register_globals(void** GpuBinaryHandle) {
169 /// __cudaRegisterFunction(GpuBinaryHandle,Kernel0,...);
170 /// ...
171 /// __cudaRegisterFunction(GpuBinaryHandle,KernelM,...);
172 /// __cudaRegisterVar(GpuBinaryHandle, GlobalVar0, ...);
173 /// ...
174 /// __cudaRegisterVar(GpuBinaryHandle, GlobalVarN, ...);
175 /// }
176 /// \endcode
177 llvm::Function *CGNVCUDARuntime::makeRegisterGlobalsFn() {
178  // No need to register anything
179  if (EmittedKernels.empty() && DeviceVars.empty())
180  return nullptr;
181 
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);
188  Builder.SetInsertPoint(EntryBB);
189 
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");
198 
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);
212  }
213 
214  // void __cudaRegisterVar(void **, char *, char *, const char *,
215  // int, int, int, int)
216  llvm::Type *RegisterVarParams[] = {VoidPtrPtrTy, CharPtrTy, CharPtrTy,
217  CharPtrTy, IntTy, IntTy,
218  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());
226  uint64_t VarSize =
227  CGM.getDataLayout().getTypeAllocSize(Var->getValueType());
228  llvm::Value *Args[] = {
229  &GpuBinaryHandlePtr,
230  Builder.CreateBitCast(Var, VoidPtrTy),
231  VarName,
232  VarName,
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);
238  }
239 
240  Builder.CreateRetVoid();
241  return RegisterKernelsFunc;
242 }
243 
244 /// Creates a global constructor function for the module:
245 /// \code
246 /// void __cuda_module_ctor(void*) {
247 /// Handle0 = __cudaRegisterFatBinary(GpuBinaryBlob0);
248 /// __cuda_register_globals(Handle0);
249 /// ...
250 /// HandleN = __cudaRegisterFatBinary(GpuBinaryBlobN);
251 /// __cuda_register_globals(HandleN);
252 /// }
253 /// \endcode
254 llvm::Function *CGNVCUDARuntime::makeModuleCtorFunction() {
255  // No need to generate ctors/dtors if there are no GPU binaries.
256  if (CGM.getCodeGenOpts().CudaGpuBinaryFileNames.empty())
257  return nullptr;
258 
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);
268 
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);
275 
276  CtorBuilder.SetInsertPoint(CtorEntryBB);
277 
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
282  // the GPU side.
283  for (const std::string &GpuBinaryFileName :
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
289  << EC.message();
290  continue;
291  }
292 
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");
305 
306  // GpuBinaryHandle = __cudaRegisterFatBinary(&FatbinWrapper);
307  llvm::CallInst *RegisterFatbinCall = CtorBuilder.CreateCall(
308  RegisterFatbinFunc,
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());
315 
316  // Call __cuda_register_globals(GpuBinaryHandle);
317  if (RegisterGlobalsFunc)
318  CtorBuilder.CreateCall(RegisterGlobalsFunc, RegisterFatbinCall);
319 
320  // Save GpuBinaryHandle so we can unregister it in destructor.
321  GpuBinaryHandles.push_back(GpuBinaryHandle);
322  }
323 
324  CtorBuilder.CreateRetVoid();
325  return ModuleCtorFunc;
326 }
327 
328 /// Creates a global destructor function that unregisters all GPU code blobs
329 /// registered by constructor.
330 /// \code
331 /// void __cuda_module_dtor(void*) {
332 /// __cudaUnregisterFatBinary(Handle0);
333 /// ...
334 /// __cudaUnregisterFatBinary(HandleN);
335 /// }
336 /// \endcode
337 llvm::Function *CGNVCUDARuntime::makeModuleDtorFunction() {
338  // No need for destructor if we don't have handles to unregister.
339  if (GpuBinaryHandles.empty())
340  return nullptr;
341 
342  // void __cudaUnregisterFatBinary(void ** handle);
343  llvm::Constant *UnregisterFatbinFunc = CGM.CreateRuntimeFunction(
344  llvm::FunctionType::get(VoidTy, VoidPtrPtrTy, false),
345  "__cudaUnregisterFatBinary");
346 
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);
354 
355  for (llvm::GlobalVariable *GpuBinaryHandle : GpuBinaryHandles) {
356  auto HandleValue =
357  DtorBuilder.CreateAlignedLoad(GpuBinaryHandle, CGM.getPointerAlign());
358  DtorBuilder.CreateCall(UnregisterFatbinFunc, HandleValue);
359  }
360 
361  DtorBuilder.CreateRetVoid();
362  return ModuleDtorFunc;
363 }
364 
366  return new CGNVCUDARuntime(CGM);
367 }
llvm::IntegerType * IntTy
int
CanQualType VoidPtrTy
Definition: ASTContext.h:908
CanQualType getSizeType() const
Return the unique type for "size_t" (C99 7.17), defined in <stddef.h>.
const llvm::DataLayout & getDataLayout() const
DiagnosticBuilder Report(SourceLocation Loc, unsigned DiagID)
Issue the message to the client.
Definition: Diagnostic.h:1124
Address GetAddrOfLocalVar(const VarDecl *VD)
GetAddrOfLocalVar - Return the address of a local variable.
std::vector< std::string > CudaGpuBinaryFileNames
A list of file names passed with -fcuda-include-gpubinary options to forward to CUDA runtime back-end...
class LLVM_ALIGNAS(8) DependentTemplateSpecializationType const IdentifierInfo * Name
Represents a template specialization type whose template cannot be resolved, e.g. ...
Definition: Type.h:4549
CodeGenFunction - This class organizes the per-function state that is used while generating LLVM code...
llvm::Type * ConvertType(QualType T)
ConvertType - Convert type T into a llvm::Type.
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:92
llvm::BasicBlock * createBasicBlock(const Twine &name="", llvm::Function *parent=nullptr, llvm::BasicBlock *before=nullptr)
createBasicBlock - Create an LLVM basic block.
detail::InMemoryDirectory::const_iterator I
llvm::CallSite EmitRuntimeCallOrInvoke(llvm::Value *callee, ArrayRef< llvm::Value * > args, const Twine &name="")
Emits a call or invoke instruction to the given runtime function.
Definition: CGCall.cpp:3456
ASTContext * Context
llvm::Value * getPointer() const
Definition: Address.h:38
ASTContext & getContext() const
The l-value was considered opaque, so the alignment was determined from a type.
llvm::Constant * CreateRuntimeFunction(llvm::FunctionType *Ty, StringRef Name, llvm::AttributeSet ExtraAttrs=llvm::AttributeSet())
Create a new runtime function with the specified type and name.
static OMPLinearClause * Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc, OpenMPLinearClauseKind Modifier, SourceLocation ModifierLoc, SourceLocation ColonLoc, SourceLocation EndLoc, ArrayRef< Expr * > VL, ArrayRef< Expr * > PL, ArrayRef< Expr * > IL, Expr *Step, Expr *CalcStep, Stmt *PreInit, Expr *PostUpdate)
Creates clause with a list of variables VL and a linear step Step.
const CodeGenOptions & getCodeGenOpts() const
FunctionArgList - Type for representing both the decl and type of parameters to a function...
Definition: CGCall.h:146
CanQualType CharTy
Definition: ASTContext.h:895
This class organizes the cross-function state that is used while generating LLVM code.
detail::InMemoryDirectory::const_iterator E
This class organizes the cross-module state that is used while lowering AST types to LLVM types...
Definition: CodeGenTypes.h:120
Internal linkage, which indicates that the entity can be referred to from within the translation unit...
Definition: Linkage.h:33
void EmitBlock(llvm::BasicBlock *BB, bool IsFinished=false)
EmitBlock - Emit the given block.
Definition: CGStmt.cpp:397
CGCUDARuntime * CreateNVCUDARuntime(CodeGenModule &CGM)
Creates an instance of a CUDA runtime class.
Definition: CGCUDANV.cpp:365
DiagnosticsEngine & getDiags() const
BoundNodesTreeBuilder *const Builder
void EmitBranch(llvm::BasicBlock *Block)
EmitBranch - Emit a branch to the specified basic block from the current insert block, taking care to avoid creation of branches from dummy blocks.
Definition: CGStmt.cpp:417
CanQualType IntTy
Definition: ASTContext.h:901