xref: /llvm-project/llvm/lib/Target/AMDGPU/AMDGPUPrintfRuntimeBinding.cpp (revision 438315bf69c7dae68edd5c99f9672fffdc442a79)
1 //=== AMDGPUPrintfRuntimeBinding.cpp - OpenCL printf implementation -------===//
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 // \file
9 //
10 // The pass bind printfs to a kernel arg pointer that will be bound to a buffer
11 // later by the runtime.
12 //
13 // This pass traverses the functions in the module and converts
14 // each call to printf to a sequence of operations that
15 // store the following into the printf buffer:
16 // - format string (passed as a module's metadata unique ID)
17 // - bitwise copies of printf arguments
18 // The backend passes will need to store metadata in the kernel
19 //===----------------------------------------------------------------------===//
20 
21 #include "AMDGPU.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/ADT/Triple.h"
25 #include "llvm/Analysis/InstructionSimplify.h"
26 #include "llvm/Analysis/TargetLibraryInfo.h"
27 #include "llvm/CodeGen/Passes.h"
28 #include "llvm/IR/Constants.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/Dominators.h"
31 #include "llvm/IR/GlobalVariable.h"
32 #include "llvm/IR/IRBuilder.h"
33 #include "llvm/IR/InstVisitor.h"
34 #include "llvm/IR/Instructions.h"
35 #include "llvm/IR/Module.h"
36 #include "llvm/IR/Type.h"
37 #include "llvm/Support/CommandLine.h"
38 #include "llvm/Support/Debug.h"
39 #include "llvm/Support/raw_ostream.h"
40 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
41 using namespace llvm;
42 
43 #define DEBUG_TYPE "printfToRuntime"
44 #define DWORD_ALIGN 4
45 
46 namespace {
47 class LLVM_LIBRARY_VISIBILITY AMDGPUPrintfRuntimeBinding final
48     : public ModulePass,
49       public InstVisitor<AMDGPUPrintfRuntimeBinding> {
50 
51 public:
52   static char ID;
53 
54   explicit AMDGPUPrintfRuntimeBinding();
55 
56   void visitCallSite(CallSite CS) {
57     Function *F = CS.getCalledFunction();
58     if (F && F->hasName() && F->getName() == "printf")
59       Printfs.push_back(CS.getInstruction());
60   }
61 
62 private:
63   bool runOnModule(Module &M) override;
64   void getConversionSpecifiers(SmallVectorImpl<char> &OpConvSpecifiers,
65                                StringRef fmt, size_t num_ops) const;
66 
67   bool shouldPrintAsStr(char Specifier, Type *OpType) const;
68   bool lowerPrintfForGpu(Module &M);
69 
70   void getAnalysisUsage(AnalysisUsage &AU) const override {
71     AU.addRequired<TargetLibraryInfoWrapperPass>();
72     AU.addRequired<DominatorTreeWrapperPass>();
73   }
74 
75   Value *simplify(Instruction *I) {
76     return SimplifyInstruction(I, {*TD, TLI, DT});
77   }
78 
79   const DataLayout *TD;
80   const DominatorTree *DT;
81   const TargetLibraryInfo *TLI;
82   SmallVector<Value *, 32> Printfs;
83 };
84 } // namespace
85 
86 char AMDGPUPrintfRuntimeBinding::ID = 0;
87 
88 INITIALIZE_PASS_BEGIN(AMDGPUPrintfRuntimeBinding,
89                       "amdgpu-printf-runtime-binding", "AMDGPU Printf lowering",
90                       false, false)
91 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
92 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
93 INITIALIZE_PASS_END(AMDGPUPrintfRuntimeBinding, "amdgpu-printf-runtime-binding",
94                     "AMDGPU Printf lowering", false, false)
95 
96 char &llvm::AMDGPUPrintfRuntimeBindingID = AMDGPUPrintfRuntimeBinding::ID;
97 
98 namespace llvm {
99 ModulePass *createAMDGPUPrintfRuntimeBinding() {
100   return new AMDGPUPrintfRuntimeBinding();
101 }
102 } // namespace llvm
103 
104 AMDGPUPrintfRuntimeBinding::AMDGPUPrintfRuntimeBinding()
105     : ModulePass(ID), TD(nullptr), DT(nullptr), TLI(nullptr) {
106   initializeAMDGPUPrintfRuntimeBindingPass(*PassRegistry::getPassRegistry());
107 }
108 
109 void AMDGPUPrintfRuntimeBinding::getConversionSpecifiers(
110     SmallVectorImpl<char> &OpConvSpecifiers, StringRef Fmt,
111     size_t NumOps) const {
112   // not all format characters are collected.
113   // At this time the format characters of interest
114   // are %p and %s, which use to know if we
115   // are either storing a literal string or a
116   // pointer to the printf buffer.
117   static const char ConvSpecifiers[] = "cdieEfgGaosuxXp";
118   size_t CurFmtSpecifierIdx = 0;
119   size_t PrevFmtSpecifierIdx = 0;
120 
121   while ((CurFmtSpecifierIdx = Fmt.find_first_of(
122               ConvSpecifiers, CurFmtSpecifierIdx)) != StringRef::npos) {
123     bool ArgDump = false;
124     StringRef CurFmt = Fmt.substr(PrevFmtSpecifierIdx,
125                                   CurFmtSpecifierIdx - PrevFmtSpecifierIdx);
126     size_t pTag = CurFmt.find_last_of("%");
127     if (pTag != StringRef::npos) {
128       ArgDump = true;
129       while (pTag && CurFmt[--pTag] == '%') {
130         ArgDump = !ArgDump;
131       }
132     }
133 
134     if (ArgDump)
135       OpConvSpecifiers.push_back(Fmt[CurFmtSpecifierIdx]);
136 
137     PrevFmtSpecifierIdx = ++CurFmtSpecifierIdx;
138   }
139 }
140 
141 bool AMDGPUPrintfRuntimeBinding::shouldPrintAsStr(char Specifier,
142                                                   Type *OpType) const {
143   if (Specifier != 's')
144     return false;
145   const PointerType *PT = dyn_cast<PointerType>(OpType);
146   if (!PT || PT->getAddressSpace() != AMDGPUAS::CONSTANT_ADDRESS)
147     return false;
148   Type *ElemType = PT->getContainedType(0);
149   if (ElemType->getTypeID() != Type::IntegerTyID)
150     return false;
151   IntegerType *ElemIType = cast<IntegerType>(ElemType);
152   return ElemIType->getBitWidth() == 8;
153 }
154 
155 bool AMDGPUPrintfRuntimeBinding::lowerPrintfForGpu(Module &M) {
156   LLVMContext &Ctx = M.getContext();
157   IRBuilder<> Builder(Ctx);
158   Type *I32Ty = Type::getInt32Ty(Ctx);
159   unsigned UniqID = 0;
160   // NB: This is important for this string size to be divizable by 4
161   const char NonLiteralStr[4] = "???";
162 
163   for (auto P : Printfs) {
164     CallInst *CI = dyn_cast<CallInst>(P);
165 
166     unsigned NumOps = CI->getNumArgOperands();
167 
168     SmallString<16> OpConvSpecifiers;
169     Value *Op = CI->getArgOperand(0);
170 
171     if (auto LI = dyn_cast<LoadInst>(Op)) {
172       Op = LI->getPointerOperand();
173       for (auto Use : Op->users()) {
174         if (auto SI = dyn_cast<StoreInst>(Use)) {
175           Op = SI->getValueOperand();
176           break;
177         }
178       }
179     }
180 
181     if (auto I = dyn_cast<Instruction>(Op)) {
182       Value *Op_simplified = simplify(I);
183       if (Op_simplified)
184         Op = Op_simplified;
185     }
186 
187     ConstantExpr *ConstExpr = dyn_cast<ConstantExpr>(Op);
188 
189     if (ConstExpr) {
190       GlobalVariable *GVar = dyn_cast<GlobalVariable>(ConstExpr->getOperand(0));
191 
192       StringRef Str("unknown");
193       if (GVar && GVar->hasInitializer()) {
194         auto Init = GVar->getInitializer();
195         if (auto CA = dyn_cast<ConstantDataArray>(Init)) {
196           if (CA->isString())
197             Str = CA->getAsCString();
198         } else if (isa<ConstantAggregateZero>(Init)) {
199           Str = "";
200         }
201         //
202         // we need this call to ascertain
203         // that we are printing a string
204         // or a pointer. It takes out the
205         // specifiers and fills up the first
206         // arg
207         getConversionSpecifiers(OpConvSpecifiers, Str, NumOps - 1);
208       }
209       // Add metadata for the string
210       std::string AStreamHolder;
211       raw_string_ostream Sizes(AStreamHolder);
212       int Sum = DWORD_ALIGN;
213       Sizes << CI->getNumArgOperands() - 1;
214       Sizes << ':';
215       for (unsigned ArgCount = 1; ArgCount < CI->getNumArgOperands() &&
216                                   ArgCount <= OpConvSpecifiers.size();
217            ArgCount++) {
218         Value *Arg = CI->getArgOperand(ArgCount);
219         Type *ArgType = Arg->getType();
220         unsigned ArgSize = TD->getTypeAllocSizeInBits(ArgType);
221         ArgSize = ArgSize / 8;
222         //
223         // ArgSize by design should be a multiple of DWORD_ALIGN,
224         // expand the arguments that do not follow this rule.
225         //
226         if (ArgSize % DWORD_ALIGN != 0) {
227           llvm::Type *ResType = llvm::Type::getInt32Ty(Ctx);
228           VectorType *LLVMVecType = llvm::dyn_cast<llvm::VectorType>(ArgType);
229           int NumElem = LLVMVecType ? LLVMVecType->getNumElements() : 1;
230           if (LLVMVecType && NumElem > 1)
231             ResType = llvm::VectorType::get(ResType, NumElem);
232           Builder.SetInsertPoint(CI);
233           Builder.SetCurrentDebugLocation(CI->getDebugLoc());
234           if (OpConvSpecifiers[ArgCount - 1] == 'x' ||
235               OpConvSpecifiers[ArgCount - 1] == 'X' ||
236               OpConvSpecifiers[ArgCount - 1] == 'u' ||
237               OpConvSpecifiers[ArgCount - 1] == 'o')
238             Arg = Builder.CreateZExt(Arg, ResType);
239           else
240             Arg = Builder.CreateSExt(Arg, ResType);
241           ArgType = Arg->getType();
242           ArgSize = TD->getTypeAllocSizeInBits(ArgType);
243           ArgSize = ArgSize / 8;
244           CI->setOperand(ArgCount, Arg);
245         }
246         if (OpConvSpecifiers[ArgCount - 1] == 'f') {
247           ConstantFP *FpCons = dyn_cast<ConstantFP>(Arg);
248           if (FpCons)
249             ArgSize = 4;
250           else {
251             FPExtInst *FpExt = dyn_cast<FPExtInst>(Arg);
252             if (FpExt && FpExt->getType()->isDoubleTy() &&
253                 FpExt->getOperand(0)->getType()->isFloatTy())
254               ArgSize = 4;
255           }
256         }
257         if (shouldPrintAsStr(OpConvSpecifiers[ArgCount - 1], ArgType)) {
258           if (ConstantExpr *ConstExpr = dyn_cast<ConstantExpr>(Arg)) {
259             GlobalVariable *GV =
260                 dyn_cast<GlobalVariable>(ConstExpr->getOperand(0));
261             if (GV && GV->hasInitializer()) {
262               Constant *Init = GV->getInitializer();
263               ConstantDataArray *CA = dyn_cast<ConstantDataArray>(Init);
264               if (Init->isZeroValue() || CA->isString()) {
265                 size_t SizeStr = Init->isZeroValue()
266                                      ? 1
267                                      : (strlen(CA->getAsCString().data()) + 1);
268                 size_t Rem = SizeStr % DWORD_ALIGN;
269                 size_t NSizeStr = 0;
270                 LLVM_DEBUG(dbgs() << "Printf string original size = " << SizeStr
271                                   << '\n');
272                 if (Rem) {
273                   NSizeStr = SizeStr + (DWORD_ALIGN - Rem);
274                 } else {
275                   NSizeStr = SizeStr;
276                 }
277                 ArgSize = NSizeStr;
278               }
279             } else {
280               ArgSize = sizeof(NonLiteralStr);
281             }
282           } else {
283             ArgSize = sizeof(NonLiteralStr);
284           }
285         }
286         LLVM_DEBUG(dbgs() << "Printf ArgSize (in buffer) = " << ArgSize
287                           << " for type: " << *ArgType << '\n');
288         Sizes << ArgSize << ':';
289         Sum += ArgSize;
290       }
291       LLVM_DEBUG(dbgs() << "Printf format string in source = " << Str.str()
292                         << '\n');
293       for (size_t I = 0; I < Str.size(); ++I) {
294         // Rest of the C escape sequences (e.g. \') are handled correctly
295         // by the MDParser
296         switch (Str[I]) {
297         case '\a':
298           Sizes << "\\a";
299           break;
300         case '\b':
301           Sizes << "\\b";
302           break;
303         case '\f':
304           Sizes << "\\f";
305           break;
306         case '\n':
307           Sizes << "\\n";
308           break;
309         case '\r':
310           Sizes << "\\r";
311           break;
312         case '\v':
313           Sizes << "\\v";
314           break;
315         case ':':
316           // ':' cannot be scanned by Flex, as it is defined as a delimiter
317           // Replace it with it's octal representation \72
318           Sizes << "\\72";
319           break;
320         default:
321           Sizes << Str[I];
322           break;
323         }
324       }
325 
326       // Insert the printf_alloc call
327       Builder.SetInsertPoint(CI);
328       Builder.SetCurrentDebugLocation(CI->getDebugLoc());
329 
330       AttributeList Attr = AttributeList::get(Ctx, AttributeList::FunctionIndex,
331                                               Attribute::NoUnwind);
332 
333       Type *SizetTy = Type::getInt32Ty(Ctx);
334 
335       Type *Tys_alloc[1] = {SizetTy};
336       Type *I8Ptr = PointerType::get(Type::getInt8Ty(Ctx), 1);
337       FunctionType *FTy_alloc = FunctionType::get(I8Ptr, Tys_alloc, false);
338       FunctionCallee PrintfAllocFn =
339           M.getOrInsertFunction(StringRef("__printf_alloc"), FTy_alloc, Attr);
340 
341       LLVM_DEBUG(dbgs() << "Printf metadata = " << Sizes.str() << '\n');
342       std::string fmtstr = itostr(++UniqID) + ":" + Sizes.str().c_str();
343       MDString *fmtStrArray = MDString::get(Ctx, fmtstr);
344 
345       // Instead of creating global variables, the
346       // printf format strings are extracted
347       // and passed as metadata. This avoids
348       // polluting llvm's symbol tables in this module.
349       // Metadata is going to be extracted
350       // by the backend passes and inserted
351       // into the OpenCL binary as appropriate.
352       StringRef amd("llvm.printf.fmts");
353       NamedMDNode *metaD = M.getOrInsertNamedMetadata(amd);
354       MDNode *myMD = MDNode::get(Ctx, fmtStrArray);
355       metaD->addOperand(myMD);
356       Value *sumC = ConstantInt::get(SizetTy, Sum, false);
357       SmallVector<Value *, 1> alloc_args;
358       alloc_args.push_back(sumC);
359       CallInst *pcall =
360           CallInst::Create(PrintfAllocFn, alloc_args, "printf_alloc_fn", CI);
361 
362       //
363       // Insert code to split basicblock with a
364       // piece of hammock code.
365       // basicblock splits after buffer overflow check
366       //
367       ConstantPointerNull *zeroIntPtr =
368           ConstantPointerNull::get(PointerType::get(Type::getInt8Ty(Ctx), 1));
369       ICmpInst *cmp =
370           dyn_cast<ICmpInst>(Builder.CreateICmpNE(pcall, zeroIntPtr, ""));
371       if (!CI->use_empty()) {
372         Value *result =
373             Builder.CreateSExt(Builder.CreateNot(cmp), I32Ty, "printf_res");
374         CI->replaceAllUsesWith(result);
375       }
376       SplitBlock(CI->getParent(), cmp);
377       Instruction *Brnch =
378           SplitBlockAndInsertIfThen(cmp, cmp->getNextNode(), false);
379 
380       Builder.SetInsertPoint(Brnch);
381 
382       // store unique printf id in the buffer
383       //
384       SmallVector<Value *, 1> ZeroIdxList;
385       ConstantInt *zeroInt =
386           ConstantInt::get(Ctx, APInt(32, StringRef("0"), 10));
387       ZeroIdxList.push_back(zeroInt);
388 
389       GetElementPtrInst *BufferIdx =
390           dyn_cast<GetElementPtrInst>(GetElementPtrInst::Create(
391               nullptr, pcall, ZeroIdxList, "PrintBuffID", Brnch));
392 
393       Type *idPointer = PointerType::get(I32Ty, AMDGPUAS::GLOBAL_ADDRESS);
394       Value *id_gep_cast =
395           new BitCastInst(BufferIdx, idPointer, "PrintBuffIdCast", Brnch);
396 
397       StoreInst *stbuff =
398           new StoreInst(ConstantInt::get(I32Ty, UniqID), id_gep_cast);
399       stbuff->insertBefore(Brnch); // to Remove unused variable warning
400 
401       SmallVector<Value *, 2> FourthIdxList;
402       ConstantInt *fourInt =
403           ConstantInt::get(Ctx, APInt(32, StringRef("4"), 10));
404 
405       FourthIdxList.push_back(fourInt); // 1st 4 bytes hold the printf_id
406       // the following GEP is the buffer pointer
407       BufferIdx = cast<GetElementPtrInst>(GetElementPtrInst::Create(
408           nullptr, pcall, FourthIdxList, "PrintBuffGep", Brnch));
409 
410       Type *Int32Ty = Type::getInt32Ty(Ctx);
411       Type *Int64Ty = Type::getInt64Ty(Ctx);
412       for (unsigned ArgCount = 1; ArgCount < CI->getNumArgOperands() &&
413                                   ArgCount <= OpConvSpecifiers.size();
414            ArgCount++) {
415         Value *Arg = CI->getArgOperand(ArgCount);
416         Type *ArgType = Arg->getType();
417         SmallVector<Value *, 32> WhatToStore;
418         if (ArgType->isFPOrFPVectorTy() &&
419             (ArgType->getTypeID() != Type::VectorTyID)) {
420           Type *IType = (ArgType->isFloatTy()) ? Int32Ty : Int64Ty;
421           if (OpConvSpecifiers[ArgCount - 1] == 'f') {
422             ConstantFP *fpCons = dyn_cast<ConstantFP>(Arg);
423             if (fpCons) {
424               APFloat Val(fpCons->getValueAPF());
425               bool Lost = false;
426               Val.convert(APFloat::IEEEsingle(), APFloat::rmNearestTiesToEven,
427                           &Lost);
428               Arg = ConstantFP::get(Ctx, Val);
429               IType = Int32Ty;
430             } else {
431               FPExtInst *FpExt = dyn_cast<FPExtInst>(Arg);
432               if (FpExt && FpExt->getType()->isDoubleTy() &&
433                   FpExt->getOperand(0)->getType()->isFloatTy()) {
434                 Arg = FpExt->getOperand(0);
435                 IType = Int32Ty;
436               }
437             }
438           }
439           Arg = new BitCastInst(Arg, IType, "PrintArgFP", Brnch);
440           WhatToStore.push_back(Arg);
441         } else if (ArgType->getTypeID() == Type::PointerTyID) {
442           if (shouldPrintAsStr(OpConvSpecifiers[ArgCount - 1], ArgType)) {
443             const char *S = NonLiteralStr;
444             if (ConstantExpr *ConstExpr = dyn_cast<ConstantExpr>(Arg)) {
445               GlobalVariable *GV =
446                   dyn_cast<GlobalVariable>(ConstExpr->getOperand(0));
447               if (GV && GV->hasInitializer()) {
448                 Constant *Init = GV->getInitializer();
449                 ConstantDataArray *CA = dyn_cast<ConstantDataArray>(Init);
450                 if (Init->isZeroValue() || CA->isString()) {
451                   S = Init->isZeroValue() ? "" : CA->getAsCString().data();
452                 }
453               }
454             }
455             size_t SizeStr = strlen(S) + 1;
456             size_t Rem = SizeStr % DWORD_ALIGN;
457             size_t NSizeStr = 0;
458             if (Rem) {
459               NSizeStr = SizeStr + (DWORD_ALIGN - Rem);
460             } else {
461               NSizeStr = SizeStr;
462             }
463             if (S[0]) {
464               char *MyNewStr = new char[NSizeStr]();
465               strcpy(MyNewStr, S);
466               int NumInts = NSizeStr / 4;
467               int CharC = 0;
468               while (NumInts) {
469                 int ANum = *(int *)(MyNewStr + CharC);
470                 CharC += 4;
471                 NumInts--;
472                 Value *ANumV = ConstantInt::get(Int32Ty, ANum, false);
473                 WhatToStore.push_back(ANumV);
474               }
475               delete[] MyNewStr;
476             } else {
477               // Empty string, give a hint to RT it is no NULL
478               Value *ANumV = ConstantInt::get(Int32Ty, 0xFFFFFF00, false);
479               WhatToStore.push_back(ANumV);
480             }
481           } else {
482             uint64_t Size = TD->getTypeAllocSizeInBits(ArgType);
483             assert((Size == 32 || Size == 64) && "unsupported size");
484             Type *DstType = (Size == 32) ? Int32Ty : Int64Ty;
485             Arg = new PtrToIntInst(Arg, DstType, "PrintArgPtr", Brnch);
486             WhatToStore.push_back(Arg);
487           }
488         } else if (ArgType->getTypeID() == Type::VectorTyID) {
489           Type *IType = NULL;
490           uint32_t EleCount = cast<VectorType>(ArgType)->getNumElements();
491           uint32_t EleSize = ArgType->getScalarSizeInBits();
492           uint32_t TotalSize = EleCount * EleSize;
493           if (EleCount == 3) {
494             IntegerType *Int32Ty = Type::getInt32Ty(ArgType->getContext());
495             Constant *Indices[4] = {
496                 ConstantInt::get(Int32Ty, 0), ConstantInt::get(Int32Ty, 1),
497                 ConstantInt::get(Int32Ty, 2), ConstantInt::get(Int32Ty, 2)};
498             Constant *Mask = ConstantVector::get(Indices);
499             ShuffleVectorInst *Shuffle = new ShuffleVectorInst(Arg, Arg, Mask);
500             Shuffle->insertBefore(Brnch);
501             Arg = Shuffle;
502             ArgType = Arg->getType();
503             TotalSize += EleSize;
504           }
505           switch (EleSize) {
506           default:
507             EleCount = TotalSize / 64;
508             IType = dyn_cast<Type>(Type::getInt64Ty(ArgType->getContext()));
509             break;
510           case 8:
511             if (EleCount >= 8) {
512               EleCount = TotalSize / 64;
513               IType = dyn_cast<Type>(Type::getInt64Ty(ArgType->getContext()));
514             } else if (EleCount >= 3) {
515               EleCount = 1;
516               IType = dyn_cast<Type>(Type::getInt32Ty(ArgType->getContext()));
517             } else {
518               EleCount = 1;
519               IType = dyn_cast<Type>(Type::getInt16Ty(ArgType->getContext()));
520             }
521             break;
522           case 16:
523             if (EleCount >= 3) {
524               EleCount = TotalSize / 64;
525               IType = dyn_cast<Type>(Type::getInt64Ty(ArgType->getContext()));
526             } else {
527               EleCount = 1;
528               IType = dyn_cast<Type>(Type::getInt32Ty(ArgType->getContext()));
529             }
530             break;
531           }
532           if (EleCount > 1) {
533             IType = dyn_cast<Type>(VectorType::get(IType, EleCount));
534           }
535           Arg = new BitCastInst(Arg, IType, "PrintArgVect", Brnch);
536           WhatToStore.push_back(Arg);
537         } else {
538           WhatToStore.push_back(Arg);
539         }
540         for (unsigned I = 0, E = WhatToStore.size(); I != E; ++I) {
541           Value *TheBtCast = WhatToStore[I];
542           unsigned ArgSize =
543               TD->getTypeAllocSizeInBits(TheBtCast->getType()) / 8;
544           SmallVector<Value *, 1> BuffOffset;
545           BuffOffset.push_back(ConstantInt::get(I32Ty, ArgSize));
546 
547           Type *ArgPointer = PointerType::get(TheBtCast->getType(), 1);
548           Value *CastedGEP =
549               new BitCastInst(BufferIdx, ArgPointer, "PrintBuffPtrCast", Brnch);
550           StoreInst *StBuff = new StoreInst(TheBtCast, CastedGEP, Brnch);
551           LLVM_DEBUG(dbgs() << "inserting store to printf buffer:\n"
552                             << *StBuff << '\n');
553           (void)StBuff;
554           if (I + 1 == E && ArgCount + 1 == CI->getNumArgOperands())
555             break;
556           BufferIdx = dyn_cast<GetElementPtrInst>(GetElementPtrInst::Create(
557               nullptr, BufferIdx, BuffOffset, "PrintBuffNextPtr", Brnch));
558           LLVM_DEBUG(dbgs() << "inserting gep to the printf buffer:\n"
559                             << *BufferIdx << '\n');
560         }
561       }
562     }
563   }
564 
565   // erase the printf calls
566   for (auto P : Printfs) {
567     CallInst *CI = dyn_cast<CallInst>(P);
568     CI->eraseFromParent();
569   }
570 
571   Printfs.clear();
572   return true;
573 }
574 
575 bool AMDGPUPrintfRuntimeBinding::runOnModule(Module &M) {
576   Triple TT(M.getTargetTriple());
577   if (TT.getArch() == Triple::r600)
578     return false;
579 
580   visit(M);
581 
582   if (Printfs.empty())
583     return false;
584 
585   TD = &M.getDataLayout();
586   auto DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
587   DT = DTWP ? &DTWP->getDomTree() : nullptr;
588   TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
589 
590   return lowerPrintfForGpu(M);
591 }
592