1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
//===------ CGGPUBuiltin.cpp - Codegen for GPU builtins -------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Generates code for built-in GPU calls which are not runtime-specific.
// (Runtime-specific codegen lives in programming model specific files.)
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "clang/Basic/Builtins.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Instruction.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Transforms/Utils/AMDGPUEmitPrintf.h"
using namespace clang;
using namespace CodeGen;
static llvm::Function *GetVprintfDeclaration(llvm::Module &M) {
llvm::Type *ArgTypes[] = {llvm::Type::getInt8PtrTy(M.getContext()),
llvm::Type::getInt8PtrTy(M.getContext())};
llvm::FunctionType *VprintfFuncType = llvm::FunctionType::get(
llvm::Type::getInt32Ty(M.getContext()), ArgTypes, false);
if (auto* F = M.getFunction("vprintf")) {
// Our CUDA system header declares vprintf with the right signature, so
// nobody else should have been able to declare vprintf with a bogus
// signature.
assert(F->getFunctionType() == VprintfFuncType);
return F;
}
// vprintf doesn't already exist; create a declaration and insert it into the
// module.
return llvm::Function::Create(
VprintfFuncType, llvm::GlobalVariable::ExternalLinkage, "vprintf", &M);
}
// Transforms a call to printf into a call to the NVPTX vprintf syscall (which
// isn't particularly special; it's invoked just like a regular function).
// vprintf takes two args: A format string, and a pointer to a buffer containing
// the varargs.
//
// For example, the call
//
// printf("format string", arg1, arg2, arg3);
//
// is converted into something resembling
//
// struct Tmp {
// Arg1 a1;
// Arg2 a2;
// Arg3 a3;
// };
// char* buf = alloca(sizeof(Tmp));
// *(Tmp*)buf = {a1, a2, a3};
// vprintf("format string", buf);
//
// buf is aligned to the max of {alignof(Arg1), ...}. Furthermore, each of the
// args is itself aligned to its preferred alignment.
//
// Note that by the time this function runs, E's args have already undergone the
// standard C vararg promotion (short -> int, float -> double, etc.).
RValue
CodeGenFunction::EmitNVPTXDevicePrintfCallExpr(const CallExpr *E,
ReturnValueSlot ReturnValue) {
assert(getTarget().getTriple().isNVPTX());
assert(E->getBuiltinCallee() == Builtin::BIprintf);
assert(E->getNumArgs() >= 1); // printf always has at least one arg.
const llvm::DataLayout &DL = CGM.getDataLayout();
llvm::LLVMContext &Ctx = CGM.getLLVMContext();
CallArgList Args;
EmitCallArgs(Args,
E->getDirectCallee()->getType()->getAs<FunctionProtoType>(),
E->arguments(), E->getDirectCallee(),
/* ParamsToSkip = */ 0);
// We don't know how to emit non-scalar varargs.
if (std::any_of(Args.begin() + 1, Args.end(), [&](const CallArg &A) {
return !A.getRValue(*this).isScalar();
})) {
CGM.ErrorUnsupported(E, "non-scalar arg to printf");
return RValue::get(llvm::ConstantInt::get(IntTy, 0));
}
// Construct and fill the args buffer that we'll pass to vprintf.
llvm::Value *BufferPtr;
if (Args.size() <= 1) {
// If there are no args, pass a null pointer to vprintf.
BufferPtr = llvm::ConstantPointerNull::get(llvm::Type::getInt8PtrTy(Ctx));
} else {
llvm::SmallVector<llvm::Type *, 8> ArgTypes;
for (unsigned I = 1, NumArgs = Args.size(); I < NumArgs; ++I)
ArgTypes.push_back(Args[I].getRValue(*this).getScalarVal()->getType());
// Using llvm::StructType is correct only because printf doesn't accept
// aggregates. If we had to handle aggregates here, we'd have to manually
// compute the offsets within the alloca -- we wouldn't be able to assume
// that the alignment of the llvm type was the same as the alignment of the
// clang type.
llvm::Type *AllocaTy = llvm::StructType::create(ArgTypes, "printf_args");
llvm::Value *Alloca = CreateTempAlloca(AllocaTy);
for (unsigned I = 1, NumArgs = Args.size(); I < NumArgs; ++I) {
llvm::Value *P = Builder.CreateStructGEP(AllocaTy, Alloca, I - 1);
llvm::Value *Arg = Args[I].getRValue(*this).getScalarVal();
Builder.CreateAlignedStore(Arg, P, DL.getPrefTypeAlign(Arg->getType()));
}
BufferPtr = Builder.CreatePointerCast(Alloca, llvm::Type::getInt8PtrTy(Ctx));
}
// Invoke vprintf and return.
llvm::Function* VprintfFunc = GetVprintfDeclaration(CGM.getModule());
return RValue::get(Builder.CreateCall(
VprintfFunc, {Args[0].getRValue(*this).getScalarVal(), BufferPtr}));
}
RValue
CodeGenFunction::EmitAMDGPUDevicePrintfCallExpr(const CallExpr *E,
ReturnValueSlot ReturnValue) {
assert(getTarget().getTriple().getArch() == llvm::Triple::amdgcn);
assert(E->getBuiltinCallee() == Builtin::BIprintf ||
E->getBuiltinCallee() == Builtin::BI__builtin_printf);
assert(E->getNumArgs() >= 1); // printf always has at least one arg.
CallArgList CallArgs;
EmitCallArgs(CallArgs,
E->getDirectCallee()->getType()->getAs<FunctionProtoType>(),
E->arguments(), E->getDirectCallee(),
/* ParamsToSkip = */ 0);
SmallVector<llvm::Value *, 8> Args;
for (auto A : CallArgs) {
// We don't know how to emit non-scalar varargs.
if (!A.getRValue(*this).isScalar()) {
CGM.ErrorUnsupported(E, "non-scalar arg to printf");
return RValue::get(llvm::ConstantInt::get(IntTy, -1));
}
llvm::Value *Arg = A.getRValue(*this).getScalarVal();
Args.push_back(Arg);
}
llvm::IRBuilder<> IRB(Builder.GetInsertBlock(), Builder.GetInsertPoint());
IRB.SetCurrentDebugLocation(Builder.getCurrentDebugLocation());
auto Printf = llvm::emitAMDGPUPrintfCall(IRB, Args);
Builder.SetInsertPoint(IRB.GetInsertBlock(), IRB.GetInsertPoint());
return RValue::get(Printf);
}
|
