clang 18.0.0git
CGGPUBuiltin.cpp
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1//===------ CGGPUBuiltin.cpp - Codegen for GPU builtins -------------------===//
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// Generates code for built-in GPU calls which are not runtime-specific.
10// (Runtime-specific codegen lives in programming model specific files.)
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenFunction.h"
16#include "llvm/IR/DataLayout.h"
17#include "llvm/IR/Instruction.h"
18#include "llvm/Support/MathExtras.h"
19#include "llvm/Transforms/Utils/AMDGPUEmitPrintf.h"
20
21using namespace clang;
22using namespace CodeGen;
23
24namespace {
25llvm::Function *GetVprintfDeclaration(llvm::Module &M) {
26 llvm::Type *ArgTypes[] = {llvm::Type::getInt8PtrTy(M.getContext()),
27 llvm::Type::getInt8PtrTy(M.getContext())};
28 llvm::FunctionType *VprintfFuncType = llvm::FunctionType::get(
29 llvm::Type::getInt32Ty(M.getContext()), ArgTypes, false);
30
31 if (auto *F = M.getFunction("vprintf")) {
32 // Our CUDA system header declares vprintf with the right signature, so
33 // nobody else should have been able to declare vprintf with a bogus
34 // signature.
35 assert(F->getFunctionType() == VprintfFuncType);
36 return F;
37 }
38
39 // vprintf doesn't already exist; create a declaration and insert it into the
40 // module.
41 return llvm::Function::Create(
42 VprintfFuncType, llvm::GlobalVariable::ExternalLinkage, "vprintf", &M);
43}
44
45llvm::Function *GetOpenMPVprintfDeclaration(CodeGenModule &CGM) {
46 const char *Name = "__llvm_omp_vprintf";
47 llvm::Module &M = CGM.getModule();
48 llvm::Type *ArgTypes[] = {llvm::Type::getInt8PtrTy(M.getContext()),
49 llvm::Type::getInt8PtrTy(M.getContext()),
50 llvm::Type::getInt32Ty(M.getContext())};
51 llvm::FunctionType *VprintfFuncType = llvm::FunctionType::get(
52 llvm::Type::getInt32Ty(M.getContext()), ArgTypes, false);
53
54 if (auto *F = M.getFunction(Name)) {
55 if (F->getFunctionType() != VprintfFuncType) {
57 "Invalid type declaration for __llvm_omp_vprintf");
58 return nullptr;
59 }
60 return F;
61 }
62
63 return llvm::Function::Create(
64 VprintfFuncType, llvm::GlobalVariable::ExternalLinkage, Name, &M);
65}
66
67// Transforms a call to printf into a call to the NVPTX vprintf syscall (which
68// isn't particularly special; it's invoked just like a regular function).
69// vprintf takes two args: A format string, and a pointer to a buffer containing
70// the varargs.
71//
72// For example, the call
73//
74// printf("format string", arg1, arg2, arg3);
75//
76// is converted into something resembling
77//
78// struct Tmp {
79// Arg1 a1;
80// Arg2 a2;
81// Arg3 a3;
82// };
83// char* buf = alloca(sizeof(Tmp));
84// *(Tmp*)buf = {a1, a2, a3};
85// vprintf("format string", buf);
86//
87// buf is aligned to the max of {alignof(Arg1), ...}. Furthermore, each of the
88// args is itself aligned to its preferred alignment.
89//
90// Note that by the time this function runs, E's args have already undergone the
91// standard C vararg promotion (short -> int, float -> double, etc.).
92
93std::pair<llvm::Value *, llvm::TypeSize>
94packArgsIntoNVPTXFormatBuffer(CodeGenFunction *CGF, const CallArgList &Args) {
95 const llvm::DataLayout &DL = CGF->CGM.getDataLayout();
96 llvm::LLVMContext &Ctx = CGF->CGM.getLLVMContext();
97 CGBuilderTy &Builder = CGF->Builder;
98
99 // Construct and fill the args buffer that we'll pass to vprintf.
100 if (Args.size() <= 1) {
101 // If there are no args, pass a null pointer and size 0
102 llvm::Value * BufferPtr = llvm::ConstantPointerNull::get(llvm::Type::getInt8PtrTy(Ctx));
103 return {BufferPtr, llvm::TypeSize::Fixed(0)};
104 } else {
106 for (unsigned I = 1, NumArgs = Args.size(); I < NumArgs; ++I)
107 ArgTypes.push_back(Args[I].getRValue(*CGF).getScalarVal()->getType());
108
109 // Using llvm::StructType is correct only because printf doesn't accept
110 // aggregates. If we had to handle aggregates here, we'd have to manually
111 // compute the offsets within the alloca -- we wouldn't be able to assume
112 // that the alignment of the llvm type was the same as the alignment of the
113 // clang type.
114 llvm::Type *AllocaTy = llvm::StructType::create(ArgTypes, "printf_args");
115 llvm::Value *Alloca = CGF->CreateTempAlloca(AllocaTy);
116
117 for (unsigned I = 1, NumArgs = Args.size(); I < NumArgs; ++I) {
118 llvm::Value *P = Builder.CreateStructGEP(AllocaTy, Alloca, I - 1);
119 llvm::Value *Arg = Args[I].getRValue(*CGF).getScalarVal();
120 Builder.CreateAlignedStore(Arg, P, DL.getPrefTypeAlign(Arg->getType()));
121 }
122 llvm::Value *BufferPtr =
123 Builder.CreatePointerCast(Alloca, llvm::Type::getInt8PtrTy(Ctx));
124 return {BufferPtr, DL.getTypeAllocSize(AllocaTy)};
125 }
126}
127
128bool containsNonScalarVarargs(CodeGenFunction *CGF, const CallArgList &Args) {
129 return llvm::any_of(llvm::drop_begin(Args), [&](const CallArg &A) {
130 return !A.getRValue(*CGF).isScalar();
131 });
132}
133
134RValue EmitDevicePrintfCallExpr(const CallExpr *E, CodeGenFunction *CGF,
135 llvm::Function *Decl, bool WithSizeArg) {
136 CodeGenModule &CGM = CGF->CGM;
137 CGBuilderTy &Builder = CGF->Builder;
138 assert(E->getBuiltinCallee() == Builtin::BIprintf);
139 assert(E->getNumArgs() >= 1); // printf always has at least one arg.
140
141 // Uses the same format as nvptx for the argument packing, but also passes
142 // an i32 for the total size of the passed pointer
143 CallArgList Args;
144 CGF->EmitCallArgs(Args,
146 E->arguments(), E->getDirectCallee(),
147 /* ParamsToSkip = */ 0);
148
149 // We don't know how to emit non-scalar varargs.
150 if (containsNonScalarVarargs(CGF, Args)) {
151 CGM.ErrorUnsupported(E, "non-scalar arg to printf");
152 return RValue::get(llvm::ConstantInt::get(CGF->IntTy, 0));
153 }
154
155 auto r = packArgsIntoNVPTXFormatBuffer(CGF, Args);
156 llvm::Value *BufferPtr = r.first;
157
159 Args[0].getRValue(*CGF).getScalarVal(), BufferPtr};
160 if (WithSizeArg) {
161 // Passing > 32bit of data as a local alloca doesn't work for nvptx or
162 // amdgpu
163 llvm::Constant *Size =
164 llvm::ConstantInt::get(llvm::Type::getInt32Ty(CGM.getLLVMContext()),
165 static_cast<uint32_t>(r.second.getFixedValue()));
166
167 Vec.push_back(Size);
168 }
169 return RValue::get(Builder.CreateCall(Decl, Vec));
170}
171} // namespace
172
173RValue CodeGenFunction::EmitNVPTXDevicePrintfCallExpr(const CallExpr *E) {
174 assert(getTarget().getTriple().isNVPTX());
175 return EmitDevicePrintfCallExpr(
176 E, this, GetVprintfDeclaration(CGM.getModule()), false);
177}
178
180 assert(getTarget().getTriple().getArch() == llvm::Triple::amdgcn);
181 assert(E->getBuiltinCallee() == Builtin::BIprintf ||
182 E->getBuiltinCallee() == Builtin::BI__builtin_printf);
183 assert(E->getNumArgs() >= 1); // printf always has at least one arg.
184
185 CallArgList CallArgs;
186 EmitCallArgs(CallArgs,
188 E->arguments(), E->getDirectCallee(),
189 /* ParamsToSkip = */ 0);
190
192 for (const auto &A : CallArgs) {
193 // We don't know how to emit non-scalar varargs.
194 if (!A.getRValue(*this).isScalar()) {
195 CGM.ErrorUnsupported(E, "non-scalar arg to printf");
196 return RValue::get(llvm::ConstantInt::get(IntTy, -1));
197 }
198
199 llvm::Value *Arg = A.getRValue(*this).getScalarVal();
200 Args.push_back(Arg);
201 }
202
203 llvm::IRBuilder<> IRB(Builder.GetInsertBlock(), Builder.GetInsertPoint());
204 IRB.SetCurrentDebugLocation(Builder.getCurrentDebugLocation());
205
206 bool isBuffered = (CGM.getTarget().getTargetOpts().AMDGPUPrintfKindVal ==
208 auto Printf = llvm::emitAMDGPUPrintfCall(IRB, Args, isBuffered);
209 Builder.SetInsertPoint(IRB.GetInsertBlock(), IRB.GetInsertPoint());
210 return RValue::get(Printf);
211}
212
214 assert(getTarget().getTriple().isNVPTX() ||
215 getTarget().getTriple().isAMDGCN());
216 return EmitDevicePrintfCallExpr(E, this, GetOpenMPVprintfDeclaration(CGM),
217 true);
218}
StringRef P
Defines enum values for all the target-independent builtin functions.
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2832
unsigned getBuiltinCallee() const
getBuiltinCallee - If this is a call to a builtin, return the builtin ID of the callee.
Definition: Expr.cpp:1594
FunctionDecl * getDirectCallee()
If the callee is a FunctionDecl, return it. Otherwise return null.
Definition: Expr.h:3002
unsigned getNumArgs() const
getNumArgs - Return the number of actual arguments to this call.
Definition: Expr.h:3010
arg_range arguments()
Definition: Expr.h:3071
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:257
CodeGenFunction - This class organizes the per-function state that is used while generating LLVM code...
void EmitCallArgs(CallArgList &Args, PrototypeWrapper Prototype, llvm::iterator_range< CallExpr::const_arg_iterator > ArgRange, AbstractCallee AC=AbstractCallee(), unsigned ParamsToSkip=0, EvaluationOrder Order=EvaluationOrder::Default)
llvm::AllocaInst * CreateTempAlloca(llvm::Type *Ty, const Twine &Name="tmp", llvm::Value *ArraySize=nullptr)
CreateTempAlloca - This creates an alloca and inserts it into the entry block if ArraySize is nullptr...
const TargetInfo & getTarget() const
RValue EmitAMDGPUDevicePrintfCallExpr(const CallExpr *E)
RValue EmitOpenMPDevicePrintfCallExpr(const CallExpr *E)
This class organizes the cross-function state that is used while generating LLVM code.
llvm::Module & getModule() const
void ErrorUnsupported(const Stmt *S, const char *Type)
Print out an error that codegen doesn't support the specified stmt yet.
const TargetInfo & getTarget() const
const llvm::DataLayout & getDataLayout() const
void Error(SourceLocation loc, StringRef error)
Emit a general error that something can't be done.
llvm::LLVMContext & getLLVMContext()
RValue - This trivial value class is used to represent the result of an expression that is evaluated.
Definition: CGValue.h:39
bool isScalar() const
Definition: CGValue.h:54
static RValue get(llvm::Value *V)
Definition: CGValue.h:89
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:83
Represents a prototype with parameter type info, e.g.
Definition: Type.h:4117
Encodes a location in the source.
TargetOptions & getTargetOpts() const
Retrieve the target options.
Definition: TargetInfo.h:290
@ Buffered
printf lowering scheme involving implicit printf buffers,
AMDGPUPrintfKind AMDGPUPrintfKindVal
AMDGPU Printf lowering scheme.
const T * getAs() const
Member-template getAs<specific type>'.
Definition: Type.h:7523
QualType getType() const
Definition: Decl.h:714
RValue getRValue(CodeGenFunction &CGF) const
Definition: CGCall.cpp:4579
llvm::IntegerType * IntTy
int