llvm/llvm/lib/Transforms/Utils/AMDGPUEmitPrintf.cpp

//===- AMDGPUEmitPrintf.cpp -----------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Utility function to lower a printf call into a series of device
// library calls on the AMDGPU target.
//
// WARNING: This file knows about certain library functions. It recognizes them
// by name, and hardwires knowledge of their semantics.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/Utils/AMDGPUEmitPrintf.h"
#include "llvm/ADT/SparseBitVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/MD5.h"
#include "llvm/Support/MathExtras.h"

usingnamespacellvm;

#define DEBUG_TYPE …

static Value *fitArgInto64Bits(IRBuilder<> &Builder, Value *Arg) { … }

static Value *callPrintfBegin(IRBuilder<> &Builder, Value *Version) { … }

static Value *callAppendArgs(IRBuilder<> &Builder, Value *Desc, int NumArgs,
                             Value *Arg0, Value *Arg1, Value *Arg2, Value *Arg3,
                             Value *Arg4, Value *Arg5, Value *Arg6,
                             bool IsLast) { … }

static Value *appendArg(IRBuilder<> &Builder, Value *Desc, Value *Arg,
                        bool IsLast) { … }

// The device library does not provide strlen, so we build our own loop
// here. While we are at it, we also include the terminating null in the length.
static Value *getStrlenWithNull(IRBuilder<> &Builder, Value *Str) { … }

static Value *callAppendStringN(IRBuilder<> &Builder, Value *Desc, Value *Str,
                                Value *Length, bool isLast) { … }

static Value *appendString(IRBuilder<> &Builder, Value *Desc, Value *Arg,
                           bool IsLast) { … }

static Value *processArg(IRBuilder<> &Builder, Value *Desc, Value *Arg,
                         bool SpecIsCString, bool IsLast) { … }

// Scan the format string to locate all specifiers, and mark the ones that
// specify a string, i.e, the "%s" specifier with optional '*' characters.
static void locateCStrings(SparseBitVector<8> &BV, StringRef Str) { … }

// helper struct to package the string related data
struct StringData { … };

// Calculates frame size required for current printf expansion and allocates
// space on printf buffer. Printf frame includes following contents
// [ ControlDWord , format string/Hash , Arguments (each aligned to 8 byte) ]
static Value *callBufferedPrintfStart(
    IRBuilder<> &Builder, ArrayRef<Value *> Args, Value *Fmt,
    bool isConstFmtStr, SparseBitVector<8> &SpecIsCString,
    SmallVectorImpl<StringData> &StringContents, Value *&ArgSize) { … }

// Prepare constant string argument to push onto the buffer
static void processConstantStringArg(StringData *SD, IRBuilder<> &Builder,
                                     SmallVectorImpl<Value *> &WhatToStore) { … }

static Value *processNonStringArg(Value *Arg, IRBuilder<> &Builder) { … }

static void
callBufferedPrintfArgPush(IRBuilder<> &Builder, ArrayRef<Value *> Args,
                          Value *PtrToStore, SparseBitVector<8> &SpecIsCString,
                          SmallVectorImpl<StringData> &StringContents,
                          bool IsConstFmtStr) { … }

Value *llvm::emitAMDGPUPrintfCall(IRBuilder<> &Builder, ArrayRef<Value *> Args,
                                  bool IsBuffered) { … }