1*5ffd83dbSDimitry Andric //===- AMDGPUEmitPrintf.cpp -----------------------------------------------===// 2*5ffd83dbSDimitry Andric // 3*5ffd83dbSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*5ffd83dbSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*5ffd83dbSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*5ffd83dbSDimitry Andric // 7*5ffd83dbSDimitry Andric //===----------------------------------------------------------------------===// 8*5ffd83dbSDimitry Andric // 9*5ffd83dbSDimitry Andric // Utility function to lower a printf call into a series of device 10*5ffd83dbSDimitry Andric // library calls on the AMDGPU target. 11*5ffd83dbSDimitry Andric // 12*5ffd83dbSDimitry Andric // WARNING: This file knows about certain library functions. It recognizes them 13*5ffd83dbSDimitry Andric // by name, and hardwires knowledge of their semantics. 14*5ffd83dbSDimitry Andric // 15*5ffd83dbSDimitry Andric //===----------------------------------------------------------------------===// 16*5ffd83dbSDimitry Andric 17*5ffd83dbSDimitry Andric #include "llvm/Transforms/Utils/AMDGPUEmitPrintf.h" 18*5ffd83dbSDimitry Andric #include "llvm/ADT/SparseBitVector.h" 19*5ffd83dbSDimitry Andric #include "llvm/Analysis/ValueTracking.h" 20*5ffd83dbSDimitry Andric #include "llvm/IR/IRBuilder.h" 21*5ffd83dbSDimitry Andric 22*5ffd83dbSDimitry Andric #include <iostream> 23*5ffd83dbSDimitry Andric 24*5ffd83dbSDimitry Andric using namespace llvm; 25*5ffd83dbSDimitry Andric 26*5ffd83dbSDimitry Andric #define DEBUG_TYPE "amdgpu-emit-printf" 27*5ffd83dbSDimitry Andric 28*5ffd83dbSDimitry Andric static bool isCString(const Value *Arg) { 29*5ffd83dbSDimitry Andric auto Ty = Arg->getType(); 30*5ffd83dbSDimitry Andric auto PtrTy = dyn_cast<PointerType>(Ty); 31*5ffd83dbSDimitry Andric if (!PtrTy) 32*5ffd83dbSDimitry Andric return false; 33*5ffd83dbSDimitry Andric 34*5ffd83dbSDimitry Andric auto IntTy = dyn_cast<IntegerType>(PtrTy->getElementType()); 35*5ffd83dbSDimitry Andric if (!IntTy) 36*5ffd83dbSDimitry Andric return false; 37*5ffd83dbSDimitry Andric 38*5ffd83dbSDimitry Andric return IntTy->getBitWidth() == 8; 39*5ffd83dbSDimitry Andric } 40*5ffd83dbSDimitry Andric 41*5ffd83dbSDimitry Andric static Value *fitArgInto64Bits(IRBuilder<> &Builder, Value *Arg) { 42*5ffd83dbSDimitry Andric auto Int64Ty = Builder.getInt64Ty(); 43*5ffd83dbSDimitry Andric auto Ty = Arg->getType(); 44*5ffd83dbSDimitry Andric 45*5ffd83dbSDimitry Andric if (auto IntTy = dyn_cast<IntegerType>(Ty)) { 46*5ffd83dbSDimitry Andric switch (IntTy->getBitWidth()) { 47*5ffd83dbSDimitry Andric case 32: 48*5ffd83dbSDimitry Andric return Builder.CreateZExt(Arg, Int64Ty); 49*5ffd83dbSDimitry Andric case 64: 50*5ffd83dbSDimitry Andric return Arg; 51*5ffd83dbSDimitry Andric } 52*5ffd83dbSDimitry Andric } 53*5ffd83dbSDimitry Andric 54*5ffd83dbSDimitry Andric if (Ty->getTypeID() == Type::DoubleTyID) { 55*5ffd83dbSDimitry Andric return Builder.CreateBitCast(Arg, Int64Ty); 56*5ffd83dbSDimitry Andric } 57*5ffd83dbSDimitry Andric 58*5ffd83dbSDimitry Andric if (isa<PointerType>(Ty)) { 59*5ffd83dbSDimitry Andric return Builder.CreatePtrToInt(Arg, Int64Ty); 60*5ffd83dbSDimitry Andric } 61*5ffd83dbSDimitry Andric 62*5ffd83dbSDimitry Andric llvm_unreachable("unexpected type"); 63*5ffd83dbSDimitry Andric } 64*5ffd83dbSDimitry Andric 65*5ffd83dbSDimitry Andric static Value *callPrintfBegin(IRBuilder<> &Builder, Value *Version) { 66*5ffd83dbSDimitry Andric auto Int64Ty = Builder.getInt64Ty(); 67*5ffd83dbSDimitry Andric auto M = Builder.GetInsertBlock()->getModule(); 68*5ffd83dbSDimitry Andric auto Fn = M->getOrInsertFunction("__ockl_printf_begin", Int64Ty, Int64Ty); 69*5ffd83dbSDimitry Andric return Builder.CreateCall(Fn, Version); 70*5ffd83dbSDimitry Andric } 71*5ffd83dbSDimitry Andric 72*5ffd83dbSDimitry Andric static Value *callAppendArgs(IRBuilder<> &Builder, Value *Desc, int NumArgs, 73*5ffd83dbSDimitry Andric Value *Arg0, Value *Arg1, Value *Arg2, Value *Arg3, 74*5ffd83dbSDimitry Andric Value *Arg4, Value *Arg5, Value *Arg6, 75*5ffd83dbSDimitry Andric bool IsLast) { 76*5ffd83dbSDimitry Andric auto Int64Ty = Builder.getInt64Ty(); 77*5ffd83dbSDimitry Andric auto Int32Ty = Builder.getInt32Ty(); 78*5ffd83dbSDimitry Andric auto M = Builder.GetInsertBlock()->getModule(); 79*5ffd83dbSDimitry Andric auto Fn = M->getOrInsertFunction("__ockl_printf_append_args", Int64Ty, 80*5ffd83dbSDimitry Andric Int64Ty, Int32Ty, Int64Ty, Int64Ty, Int64Ty, 81*5ffd83dbSDimitry Andric Int64Ty, Int64Ty, Int64Ty, Int64Ty, Int32Ty); 82*5ffd83dbSDimitry Andric auto IsLastValue = Builder.getInt32(IsLast); 83*5ffd83dbSDimitry Andric auto NumArgsValue = Builder.getInt32(NumArgs); 84*5ffd83dbSDimitry Andric return Builder.CreateCall(Fn, {Desc, NumArgsValue, Arg0, Arg1, Arg2, Arg3, 85*5ffd83dbSDimitry Andric Arg4, Arg5, Arg6, IsLastValue}); 86*5ffd83dbSDimitry Andric } 87*5ffd83dbSDimitry Andric 88*5ffd83dbSDimitry Andric static Value *appendArg(IRBuilder<> &Builder, Value *Desc, Value *Arg, 89*5ffd83dbSDimitry Andric bool IsLast) { 90*5ffd83dbSDimitry Andric auto Arg0 = fitArgInto64Bits(Builder, Arg); 91*5ffd83dbSDimitry Andric auto Zero = Builder.getInt64(0); 92*5ffd83dbSDimitry Andric return callAppendArgs(Builder, Desc, 1, Arg0, Zero, Zero, Zero, Zero, Zero, 93*5ffd83dbSDimitry Andric Zero, IsLast); 94*5ffd83dbSDimitry Andric } 95*5ffd83dbSDimitry Andric 96*5ffd83dbSDimitry Andric // The device library does not provide strlen, so we build our own loop 97*5ffd83dbSDimitry Andric // here. While we are at it, we also include the terminating null in the length. 98*5ffd83dbSDimitry Andric static Value *getStrlenWithNull(IRBuilder<> &Builder, Value *Str) { 99*5ffd83dbSDimitry Andric auto *Prev = Builder.GetInsertBlock(); 100*5ffd83dbSDimitry Andric Module *M = Prev->getModule(); 101*5ffd83dbSDimitry Andric 102*5ffd83dbSDimitry Andric auto CharZero = Builder.getInt8(0); 103*5ffd83dbSDimitry Andric auto One = Builder.getInt64(1); 104*5ffd83dbSDimitry Andric auto Zero = Builder.getInt64(0); 105*5ffd83dbSDimitry Andric auto Int64Ty = Builder.getInt64Ty(); 106*5ffd83dbSDimitry Andric 107*5ffd83dbSDimitry Andric // The length is either zero for a null pointer, or the computed value for an 108*5ffd83dbSDimitry Andric // actual string. We need a join block for a phi that represents the final 109*5ffd83dbSDimitry Andric // value. 110*5ffd83dbSDimitry Andric // 111*5ffd83dbSDimitry Andric // Strictly speaking, the zero does not matter since 112*5ffd83dbSDimitry Andric // __ockl_printf_append_string_n ignores the length if the pointer is null. 113*5ffd83dbSDimitry Andric BasicBlock *Join = nullptr; 114*5ffd83dbSDimitry Andric if (Prev->getTerminator()) { 115*5ffd83dbSDimitry Andric Join = Prev->splitBasicBlock(Builder.GetInsertPoint(), 116*5ffd83dbSDimitry Andric "strlen.join"); 117*5ffd83dbSDimitry Andric Prev->getTerminator()->eraseFromParent(); 118*5ffd83dbSDimitry Andric } else { 119*5ffd83dbSDimitry Andric Join = BasicBlock::Create(M->getContext(), "strlen.join", 120*5ffd83dbSDimitry Andric Prev->getParent()); 121*5ffd83dbSDimitry Andric } 122*5ffd83dbSDimitry Andric BasicBlock *While = 123*5ffd83dbSDimitry Andric BasicBlock::Create(M->getContext(), "strlen.while", 124*5ffd83dbSDimitry Andric Prev->getParent(), Join); 125*5ffd83dbSDimitry Andric BasicBlock *WhileDone = BasicBlock::Create( 126*5ffd83dbSDimitry Andric M->getContext(), "strlen.while.done", 127*5ffd83dbSDimitry Andric Prev->getParent(), Join); 128*5ffd83dbSDimitry Andric 129*5ffd83dbSDimitry Andric // Emit an early return for when the pointer is null. 130*5ffd83dbSDimitry Andric Builder.SetInsertPoint(Prev); 131*5ffd83dbSDimitry Andric auto CmpNull = 132*5ffd83dbSDimitry Andric Builder.CreateICmpEQ(Str, Constant::getNullValue(Str->getType())); 133*5ffd83dbSDimitry Andric BranchInst::Create(Join, While, CmpNull, Prev); 134*5ffd83dbSDimitry Andric 135*5ffd83dbSDimitry Andric // Entry to the while loop. 136*5ffd83dbSDimitry Andric Builder.SetInsertPoint(While); 137*5ffd83dbSDimitry Andric 138*5ffd83dbSDimitry Andric auto PtrPhi = Builder.CreatePHI(Str->getType(), 2); 139*5ffd83dbSDimitry Andric PtrPhi->addIncoming(Str, Prev); 140*5ffd83dbSDimitry Andric auto PtrNext = Builder.CreateGEP(PtrPhi, One); 141*5ffd83dbSDimitry Andric PtrPhi->addIncoming(PtrNext, While); 142*5ffd83dbSDimitry Andric 143*5ffd83dbSDimitry Andric // Condition for the while loop. 144*5ffd83dbSDimitry Andric auto Data = Builder.CreateLoad(PtrPhi); 145*5ffd83dbSDimitry Andric auto Cmp = Builder.CreateICmpEQ(Data, CharZero); 146*5ffd83dbSDimitry Andric Builder.CreateCondBr(Cmp, WhileDone, While); 147*5ffd83dbSDimitry Andric 148*5ffd83dbSDimitry Andric // Add one to the computed length. 149*5ffd83dbSDimitry Andric Builder.SetInsertPoint(WhileDone, WhileDone->begin()); 150*5ffd83dbSDimitry Andric auto Begin = Builder.CreatePtrToInt(Str, Int64Ty); 151*5ffd83dbSDimitry Andric auto End = Builder.CreatePtrToInt(PtrPhi, Int64Ty); 152*5ffd83dbSDimitry Andric auto Len = Builder.CreateSub(End, Begin); 153*5ffd83dbSDimitry Andric Len = Builder.CreateAdd(Len, One); 154*5ffd83dbSDimitry Andric 155*5ffd83dbSDimitry Andric // Final join. 156*5ffd83dbSDimitry Andric BranchInst::Create(Join, WhileDone); 157*5ffd83dbSDimitry Andric Builder.SetInsertPoint(Join, Join->begin()); 158*5ffd83dbSDimitry Andric auto LenPhi = Builder.CreatePHI(Len->getType(), 2); 159*5ffd83dbSDimitry Andric LenPhi->addIncoming(Len, WhileDone); 160*5ffd83dbSDimitry Andric LenPhi->addIncoming(Zero, Prev); 161*5ffd83dbSDimitry Andric 162*5ffd83dbSDimitry Andric return LenPhi; 163*5ffd83dbSDimitry Andric } 164*5ffd83dbSDimitry Andric 165*5ffd83dbSDimitry Andric static Value *callAppendStringN(IRBuilder<> &Builder, Value *Desc, Value *Str, 166*5ffd83dbSDimitry Andric Value *Length, bool isLast) { 167*5ffd83dbSDimitry Andric auto Int64Ty = Builder.getInt64Ty(); 168*5ffd83dbSDimitry Andric auto CharPtrTy = Builder.getInt8PtrTy(); 169*5ffd83dbSDimitry Andric auto Int32Ty = Builder.getInt32Ty(); 170*5ffd83dbSDimitry Andric auto M = Builder.GetInsertBlock()->getModule(); 171*5ffd83dbSDimitry Andric auto Fn = M->getOrInsertFunction("__ockl_printf_append_string_n", Int64Ty, 172*5ffd83dbSDimitry Andric Int64Ty, CharPtrTy, Int64Ty, Int32Ty); 173*5ffd83dbSDimitry Andric auto IsLastInt32 = Builder.getInt32(isLast); 174*5ffd83dbSDimitry Andric return Builder.CreateCall(Fn, {Desc, Str, Length, IsLastInt32}); 175*5ffd83dbSDimitry Andric } 176*5ffd83dbSDimitry Andric 177*5ffd83dbSDimitry Andric static Value *appendString(IRBuilder<> &Builder, Value *Desc, Value *Arg, 178*5ffd83dbSDimitry Andric bool IsLast) { 179*5ffd83dbSDimitry Andric auto Length = getStrlenWithNull(Builder, Arg); 180*5ffd83dbSDimitry Andric return callAppendStringN(Builder, Desc, Arg, Length, IsLast); 181*5ffd83dbSDimitry Andric } 182*5ffd83dbSDimitry Andric 183*5ffd83dbSDimitry Andric static Value *processArg(IRBuilder<> &Builder, Value *Desc, Value *Arg, 184*5ffd83dbSDimitry Andric bool SpecIsCString, bool IsLast) { 185*5ffd83dbSDimitry Andric if (SpecIsCString && isCString(Arg)) { 186*5ffd83dbSDimitry Andric return appendString(Builder, Desc, Arg, IsLast); 187*5ffd83dbSDimitry Andric } 188*5ffd83dbSDimitry Andric // If the format specifies a string but the argument is not, the frontend will 189*5ffd83dbSDimitry Andric // have printed a warning. We just rely on undefined behaviour and send the 190*5ffd83dbSDimitry Andric // argument anyway. 191*5ffd83dbSDimitry Andric return appendArg(Builder, Desc, Arg, IsLast); 192*5ffd83dbSDimitry Andric } 193*5ffd83dbSDimitry Andric 194*5ffd83dbSDimitry Andric // Scan the format string to locate all specifiers, and mark the ones that 195*5ffd83dbSDimitry Andric // specify a string, i.e, the "%s" specifier with optional '*' characters. 196*5ffd83dbSDimitry Andric static void locateCStrings(SparseBitVector<8> &BV, Value *Fmt) { 197*5ffd83dbSDimitry Andric StringRef Str; 198*5ffd83dbSDimitry Andric if (!getConstantStringInfo(Fmt, Str) || Str.empty()) 199*5ffd83dbSDimitry Andric return; 200*5ffd83dbSDimitry Andric 201*5ffd83dbSDimitry Andric static const char ConvSpecifiers[] = "diouxXfFeEgGaAcspn"; 202*5ffd83dbSDimitry Andric size_t SpecPos = 0; 203*5ffd83dbSDimitry Andric // Skip the first argument, the format string. 204*5ffd83dbSDimitry Andric unsigned ArgIdx = 1; 205*5ffd83dbSDimitry Andric 206*5ffd83dbSDimitry Andric while ((SpecPos = Str.find_first_of('%', SpecPos)) != StringRef::npos) { 207*5ffd83dbSDimitry Andric if (Str[SpecPos + 1] == '%') { 208*5ffd83dbSDimitry Andric SpecPos += 2; 209*5ffd83dbSDimitry Andric continue; 210*5ffd83dbSDimitry Andric } 211*5ffd83dbSDimitry Andric auto SpecEnd = Str.find_first_of(ConvSpecifiers, SpecPos); 212*5ffd83dbSDimitry Andric if (SpecEnd == StringRef::npos) 213*5ffd83dbSDimitry Andric return; 214*5ffd83dbSDimitry Andric auto Spec = Str.slice(SpecPos, SpecEnd + 1); 215*5ffd83dbSDimitry Andric ArgIdx += Spec.count('*'); 216*5ffd83dbSDimitry Andric if (Str[SpecEnd] == 's') { 217*5ffd83dbSDimitry Andric BV.set(ArgIdx); 218*5ffd83dbSDimitry Andric } 219*5ffd83dbSDimitry Andric SpecPos = SpecEnd + 1; 220*5ffd83dbSDimitry Andric ++ArgIdx; 221*5ffd83dbSDimitry Andric } 222*5ffd83dbSDimitry Andric } 223*5ffd83dbSDimitry Andric 224*5ffd83dbSDimitry Andric Value *llvm::emitAMDGPUPrintfCall(IRBuilder<> &Builder, 225*5ffd83dbSDimitry Andric ArrayRef<Value *> Args) { 226*5ffd83dbSDimitry Andric auto NumOps = Args.size(); 227*5ffd83dbSDimitry Andric assert(NumOps >= 1); 228*5ffd83dbSDimitry Andric 229*5ffd83dbSDimitry Andric auto Fmt = Args[0]; 230*5ffd83dbSDimitry Andric SparseBitVector<8> SpecIsCString; 231*5ffd83dbSDimitry Andric locateCStrings(SpecIsCString, Fmt); 232*5ffd83dbSDimitry Andric 233*5ffd83dbSDimitry Andric auto Desc = callPrintfBegin(Builder, Builder.getIntN(64, 0)); 234*5ffd83dbSDimitry Andric Desc = appendString(Builder, Desc, Fmt, NumOps == 1); 235*5ffd83dbSDimitry Andric 236*5ffd83dbSDimitry Andric // FIXME: This invokes hostcall once for each argument. We can pack up to 237*5ffd83dbSDimitry Andric // seven scalar printf arguments in a single hostcall. See the signature of 238*5ffd83dbSDimitry Andric // callAppendArgs(). 239*5ffd83dbSDimitry Andric for (unsigned int i = 1; i != NumOps; ++i) { 240*5ffd83dbSDimitry Andric bool IsLast = i == NumOps - 1; 241*5ffd83dbSDimitry Andric bool IsCString = SpecIsCString.test(i); 242*5ffd83dbSDimitry Andric Desc = processArg(Builder, Desc, Args[i], IsCString, IsLast); 243*5ffd83dbSDimitry Andric } 244*5ffd83dbSDimitry Andric 245*5ffd83dbSDimitry Andric return Builder.CreateTrunc(Desc, Builder.getInt32Ty()); 246*5ffd83dbSDimitry Andric } 247