1 //===- BuildLibCalls.cpp - Utility builder for libcalls -------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements some functions that will create standard C libcalls.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Transforms/Utils/BuildLibCalls.h"
15 #include "llvm/ADT/SmallString.h"
16 #include "llvm/IR/Constants.h"
17 #include "llvm/IR/DataLayout.h"
18 #include "llvm/IR/Function.h"
19 #include "llvm/IR/IRBuilder.h"
20 #include "llvm/IR/Intrinsics.h"
21 #include "llvm/IR/LLVMContext.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/IR/Type.h"
24 #include "llvm/Target/TargetLibraryInfo.h"
25 
26 using namespace llvm;
27 
28 /// CastToCStr - Return V if it is an i8*, otherwise cast it to i8*.
29 Value *llvm::CastToCStr(Value *V, IRBuilder<> &B) {
30   unsigned AS = V->getType()->getPointerAddressSpace();
31   return B.CreateBitCast(V, B.getInt8PtrTy(AS), "cstr");
32 }
33 
34 /// EmitStrLen - Emit a call to the strlen function to the builder, for the
35 /// specified pointer.  This always returns an integer value of size intptr_t.
36 Value *llvm::EmitStrLen(Value *Ptr, IRBuilder<> &B, const DataLayout *TD,
37                         const TargetLibraryInfo *TLI) {
38   if (!TLI->has(LibFunc::strlen))
39     return nullptr;
40 
41   Module *M = B.GetInsertBlock()->getParent()->getParent();
42   AttributeSet AS[2];
43   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
44   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
45   AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
46 
47   LLVMContext &Context = B.GetInsertBlock()->getContext();
48   Constant *StrLen = M->getOrInsertFunction("strlen",
49                                             AttributeSet::get(M->getContext(),
50                                                               AS),
51                                             TD->getIntPtrType(Context),
52                                             B.getInt8PtrTy(),
53                                             NULL);
54   CallInst *CI = B.CreateCall(StrLen, CastToCStr(Ptr, B), "strlen");
55   if (const Function *F = dyn_cast<Function>(StrLen->stripPointerCasts()))
56     CI->setCallingConv(F->getCallingConv());
57 
58   return CI;
59 }
60 
61 /// EmitStrNLen - Emit a call to the strnlen function to the builder, for the
62 /// specified pointer.  Ptr is required to be some pointer type, MaxLen must
63 /// be of size_t type, and the return value has 'intptr_t' type.
64 Value *llvm::EmitStrNLen(Value *Ptr, Value *MaxLen, IRBuilder<> &B,
65                          const DataLayout *TD, const TargetLibraryInfo *TLI) {
66   if (!TLI->has(LibFunc::strnlen))
67     return nullptr;
68 
69   Module *M = B.GetInsertBlock()->getParent()->getParent();
70   AttributeSet AS[2];
71   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
72   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
73   AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
74 
75   LLVMContext &Context = B.GetInsertBlock()->getContext();
76   Constant *StrNLen = M->getOrInsertFunction("strnlen",
77                                              AttributeSet::get(M->getContext(),
78                                                               AS),
79                                              TD->getIntPtrType(Context),
80                                              B.getInt8PtrTy(),
81                                              TD->getIntPtrType(Context),
82                                              NULL);
83   CallInst *CI = B.CreateCall2(StrNLen, CastToCStr(Ptr, B), MaxLen, "strnlen");
84   if (const Function *F = dyn_cast<Function>(StrNLen->stripPointerCasts()))
85     CI->setCallingConv(F->getCallingConv());
86 
87   return CI;
88 }
89 
90 /// EmitStrChr - Emit a call to the strchr function to the builder, for the
91 /// specified pointer and character.  Ptr is required to be some pointer type,
92 /// and the return value has 'i8*' type.
93 Value *llvm::EmitStrChr(Value *Ptr, char C, IRBuilder<> &B,
94                         const DataLayout *TD, const TargetLibraryInfo *TLI) {
95   if (!TLI->has(LibFunc::strchr))
96     return nullptr;
97 
98   Module *M = B.GetInsertBlock()->getParent()->getParent();
99   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
100   AttributeSet AS =
101     AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
102 
103   Type *I8Ptr = B.getInt8PtrTy();
104   Type *I32Ty = B.getInt32Ty();
105   Constant *StrChr = M->getOrInsertFunction("strchr",
106                                             AttributeSet::get(M->getContext(),
107                                                              AS),
108                                             I8Ptr, I8Ptr, I32Ty, NULL);
109   CallInst *CI = B.CreateCall2(StrChr, CastToCStr(Ptr, B),
110                                ConstantInt::get(I32Ty, C), "strchr");
111   if (const Function *F = dyn_cast<Function>(StrChr->stripPointerCasts()))
112     CI->setCallingConv(F->getCallingConv());
113   return CI;
114 }
115 
116 /// EmitStrNCmp - Emit a call to the strncmp function to the builder.
117 Value *llvm::EmitStrNCmp(Value *Ptr1, Value *Ptr2, Value *Len,
118                          IRBuilder<> &B, const DataLayout *TD,
119                          const TargetLibraryInfo *TLI) {
120   if (!TLI->has(LibFunc::strncmp))
121     return nullptr;
122 
123   Module *M = B.GetInsertBlock()->getParent()->getParent();
124   AttributeSet AS[3];
125   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
126   AS[1] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
127   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
128   AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
129 
130   LLVMContext &Context = B.GetInsertBlock()->getContext();
131   Value *StrNCmp = M->getOrInsertFunction("strncmp",
132                                           AttributeSet::get(M->getContext(),
133                                                            AS),
134                                           B.getInt32Ty(),
135                                           B.getInt8PtrTy(),
136                                           B.getInt8PtrTy(),
137                                           TD->getIntPtrType(Context), NULL);
138   CallInst *CI = B.CreateCall3(StrNCmp, CastToCStr(Ptr1, B),
139                                CastToCStr(Ptr2, B), Len, "strncmp");
140 
141   if (const Function *F = dyn_cast<Function>(StrNCmp->stripPointerCasts()))
142     CI->setCallingConv(F->getCallingConv());
143 
144   return CI;
145 }
146 
147 /// EmitStrCpy - Emit a call to the strcpy function to the builder, for the
148 /// specified pointer arguments.
149 Value *llvm::EmitStrCpy(Value *Dst, Value *Src, IRBuilder<> &B,
150                         const DataLayout *TD, const TargetLibraryInfo *TLI,
151                         StringRef Name) {
152   if (!TLI->has(LibFunc::strcpy))
153     return nullptr;
154 
155   Module *M = B.GetInsertBlock()->getParent()->getParent();
156   AttributeSet AS[2];
157   AS[0] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
158   AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
159                             Attribute::NoUnwind);
160   Type *I8Ptr = B.getInt8PtrTy();
161   Value *StrCpy = M->getOrInsertFunction(Name,
162                                          AttributeSet::get(M->getContext(), AS),
163                                          I8Ptr, I8Ptr, I8Ptr, NULL);
164   CallInst *CI = B.CreateCall2(StrCpy, CastToCStr(Dst, B), CastToCStr(Src, B),
165                                Name);
166   if (const Function *F = dyn_cast<Function>(StrCpy->stripPointerCasts()))
167     CI->setCallingConv(F->getCallingConv());
168   return CI;
169 }
170 
171 /// EmitStrNCpy - Emit a call to the strncpy function to the builder, for the
172 /// specified pointer arguments.
173 Value *llvm::EmitStrNCpy(Value *Dst, Value *Src, Value *Len,
174                          IRBuilder<> &B, const DataLayout *TD,
175                          const TargetLibraryInfo *TLI, StringRef Name) {
176   if (!TLI->has(LibFunc::strncpy))
177     return nullptr;
178 
179   Module *M = B.GetInsertBlock()->getParent()->getParent();
180   AttributeSet AS[2];
181   AS[0] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
182   AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
183                             Attribute::NoUnwind);
184   Type *I8Ptr = B.getInt8PtrTy();
185   Value *StrNCpy = M->getOrInsertFunction(Name,
186                                           AttributeSet::get(M->getContext(),
187                                                             AS),
188                                           I8Ptr, I8Ptr, I8Ptr,
189                                           Len->getType(), NULL);
190   CallInst *CI = B.CreateCall3(StrNCpy, CastToCStr(Dst, B), CastToCStr(Src, B),
191                                Len, "strncpy");
192   if (const Function *F = dyn_cast<Function>(StrNCpy->stripPointerCasts()))
193     CI->setCallingConv(F->getCallingConv());
194   return CI;
195 }
196 
197 /// EmitMemCpyChk - Emit a call to the __memcpy_chk function to the builder.
198 /// This expects that the Len and ObjSize have type 'intptr_t' and Dst/Src
199 /// are pointers.
200 Value *llvm::EmitMemCpyChk(Value *Dst, Value *Src, Value *Len, Value *ObjSize,
201                            IRBuilder<> &B, const DataLayout *TD,
202                            const TargetLibraryInfo *TLI) {
203   if (!TLI->has(LibFunc::memcpy_chk))
204     return nullptr;
205 
206   Module *M = B.GetInsertBlock()->getParent()->getParent();
207   AttributeSet AS;
208   AS = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
209                          Attribute::NoUnwind);
210   LLVMContext &Context = B.GetInsertBlock()->getContext();
211   Value *MemCpy = M->getOrInsertFunction("__memcpy_chk",
212                                          AttributeSet::get(M->getContext(), AS),
213                                          B.getInt8PtrTy(),
214                                          B.getInt8PtrTy(),
215                                          B.getInt8PtrTy(),
216                                          TD->getIntPtrType(Context),
217                                          TD->getIntPtrType(Context), NULL);
218   Dst = CastToCStr(Dst, B);
219   Src = CastToCStr(Src, B);
220   CallInst *CI = B.CreateCall4(MemCpy, Dst, Src, Len, ObjSize);
221   if (const Function *F = dyn_cast<Function>(MemCpy->stripPointerCasts()))
222     CI->setCallingConv(F->getCallingConv());
223   return CI;
224 }
225 
226 /// EmitMemChr - Emit a call to the memchr function.  This assumes that Ptr is
227 /// a pointer, Val is an i32 value, and Len is an 'intptr_t' value.
228 Value *llvm::EmitMemChr(Value *Ptr, Value *Val,
229                         Value *Len, IRBuilder<> &B, const DataLayout *TD,
230                         const TargetLibraryInfo *TLI) {
231   if (!TLI->has(LibFunc::memchr))
232     return nullptr;
233 
234   Module *M = B.GetInsertBlock()->getParent()->getParent();
235   AttributeSet AS;
236   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
237   AS = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
238   LLVMContext &Context = B.GetInsertBlock()->getContext();
239   Value *MemChr = M->getOrInsertFunction("memchr",
240                                          AttributeSet::get(M->getContext(), AS),
241                                          B.getInt8PtrTy(),
242                                          B.getInt8PtrTy(),
243                                          B.getInt32Ty(),
244                                          TD->getIntPtrType(Context),
245                                          NULL);
246   CallInst *CI = B.CreateCall3(MemChr, CastToCStr(Ptr, B), Val, Len, "memchr");
247 
248   if (const Function *F = dyn_cast<Function>(MemChr->stripPointerCasts()))
249     CI->setCallingConv(F->getCallingConv());
250 
251   return CI;
252 }
253 
254 /// EmitMemCmp - Emit a call to the memcmp function.
255 Value *llvm::EmitMemCmp(Value *Ptr1, Value *Ptr2,
256                         Value *Len, IRBuilder<> &B, const DataLayout *TD,
257                         const TargetLibraryInfo *TLI) {
258   if (!TLI->has(LibFunc::memcmp))
259     return nullptr;
260 
261   Module *M = B.GetInsertBlock()->getParent()->getParent();
262   AttributeSet AS[3];
263   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
264   AS[1] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
265   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
266   AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
267 
268   LLVMContext &Context = B.GetInsertBlock()->getContext();
269   Value *MemCmp = M->getOrInsertFunction("memcmp",
270                                          AttributeSet::get(M->getContext(), AS),
271                                          B.getInt32Ty(),
272                                          B.getInt8PtrTy(),
273                                          B.getInt8PtrTy(),
274                                          TD->getIntPtrType(Context), NULL);
275   CallInst *CI = B.CreateCall3(MemCmp, CastToCStr(Ptr1, B), CastToCStr(Ptr2, B),
276                                Len, "memcmp");
277 
278   if (const Function *F = dyn_cast<Function>(MemCmp->stripPointerCasts()))
279     CI->setCallingConv(F->getCallingConv());
280 
281   return CI;
282 }
283 
284 /// Append a suffix to the function name according to the type of 'Op'.
285 static void AppendTypeSuffix(Value *Op, StringRef &Name, SmallString<20> &NameBuffer) {
286   if (!Op->getType()->isDoubleTy()) {
287       NameBuffer += Name;
288 
289     if (Op->getType()->isFloatTy())
290       NameBuffer += 'f';
291     else
292       NameBuffer += 'l';
293 
294     Name = NameBuffer;
295   }
296   return;
297 }
298 
299 /// EmitUnaryFloatFnCall - Emit a call to the unary function named 'Name' (e.g.
300 /// 'floor').  This function is known to take a single of type matching 'Op' and
301 /// returns one value with the same type.  If 'Op' is a long double, 'l' is
302 /// added as the suffix of name, if 'Op' is a float, we add a 'f' suffix.
303 Value *llvm::EmitUnaryFloatFnCall(Value *Op, StringRef Name, IRBuilder<> &B,
304                                   const AttributeSet &Attrs) {
305   SmallString<20> NameBuffer;
306   AppendTypeSuffix(Op, Name, NameBuffer);
307 
308   Module *M = B.GetInsertBlock()->getParent()->getParent();
309   Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
310                                          Op->getType(), NULL);
311   CallInst *CI = B.CreateCall(Callee, Op, Name);
312   CI->setAttributes(Attrs);
313   if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
314     CI->setCallingConv(F->getCallingConv());
315 
316   return CI;
317 }
318 
319 /// EmitBinaryFloatFnCall - Emit a call to the binary function named 'Name'
320 /// (e.g. 'fmin').  This function is known to take type matching 'Op1' and 'Op2'
321 /// and return one value with the same type.  If 'Op1/Op2' are long double, 'l'
322 /// is added as the suffix of name, if 'Op1/Op2' is a float, we add a 'f'
323 /// suffix.
324 Value *llvm::EmitBinaryFloatFnCall(Value *Op1, Value *Op2, StringRef Name,
325                                   IRBuilder<> &B, const AttributeSet &Attrs) {
326   SmallString<20> NameBuffer;
327   AppendTypeSuffix(Op1, Name, NameBuffer);
328 
329   Module *M = B.GetInsertBlock()->getParent()->getParent();
330   Value *Callee = M->getOrInsertFunction(Name, Op1->getType(),
331                                          Op1->getType(), Op2->getType(), NULL);
332   CallInst *CI = B.CreateCall2(Callee, Op1, Op2, Name);
333   CI->setAttributes(Attrs);
334   if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
335     CI->setCallingConv(F->getCallingConv());
336 
337   return CI;
338 }
339 
340 /// EmitPutChar - Emit a call to the putchar function.  This assumes that Char
341 /// is an integer.
342 Value *llvm::EmitPutChar(Value *Char, IRBuilder<> &B, const DataLayout *TD,
343                          const TargetLibraryInfo *TLI) {
344   if (!TLI->has(LibFunc::putchar))
345     return nullptr;
346 
347   Module *M = B.GetInsertBlock()->getParent()->getParent();
348   Value *PutChar = M->getOrInsertFunction("putchar", B.getInt32Ty(),
349                                           B.getInt32Ty(), NULL);
350   CallInst *CI = B.CreateCall(PutChar,
351                               B.CreateIntCast(Char,
352                               B.getInt32Ty(),
353                               /*isSigned*/true,
354                               "chari"),
355                               "putchar");
356 
357   if (const Function *F = dyn_cast<Function>(PutChar->stripPointerCasts()))
358     CI->setCallingConv(F->getCallingConv());
359   return CI;
360 }
361 
362 /// EmitPutS - Emit a call to the puts function.  This assumes that Str is
363 /// some pointer.
364 Value *llvm::EmitPutS(Value *Str, IRBuilder<> &B, const DataLayout *TD,
365                       const TargetLibraryInfo *TLI) {
366   if (!TLI->has(LibFunc::puts))
367     return nullptr;
368 
369   Module *M = B.GetInsertBlock()->getParent()->getParent();
370   AttributeSet AS[2];
371   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
372   AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
373                             Attribute::NoUnwind);
374 
375   Value *PutS = M->getOrInsertFunction("puts",
376                                        AttributeSet::get(M->getContext(), AS),
377                                        B.getInt32Ty(),
378                                        B.getInt8PtrTy(),
379                                        NULL);
380   CallInst *CI = B.CreateCall(PutS, CastToCStr(Str, B), "puts");
381   if (const Function *F = dyn_cast<Function>(PutS->stripPointerCasts()))
382     CI->setCallingConv(F->getCallingConv());
383   return CI;
384 }
385 
386 /// EmitFPutC - Emit a call to the fputc function.  This assumes that Char is
387 /// an integer and File is a pointer to FILE.
388 Value *llvm::EmitFPutC(Value *Char, Value *File, IRBuilder<> &B,
389                        const DataLayout *TD, const TargetLibraryInfo *TLI) {
390   if (!TLI->has(LibFunc::fputc))
391     return nullptr;
392 
393   Module *M = B.GetInsertBlock()->getParent()->getParent();
394   AttributeSet AS[2];
395   AS[0] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
396   AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
397                             Attribute::NoUnwind);
398   Constant *F;
399   if (File->getType()->isPointerTy())
400     F = M->getOrInsertFunction("fputc",
401                                AttributeSet::get(M->getContext(), AS),
402                                B.getInt32Ty(),
403                                B.getInt32Ty(), File->getType(),
404                                NULL);
405   else
406     F = M->getOrInsertFunction("fputc",
407                                B.getInt32Ty(),
408                                B.getInt32Ty(),
409                                File->getType(), NULL);
410   Char = B.CreateIntCast(Char, B.getInt32Ty(), /*isSigned*/true,
411                          "chari");
412   CallInst *CI = B.CreateCall2(F, Char, File, "fputc");
413 
414   if (const Function *Fn = dyn_cast<Function>(F->stripPointerCasts()))
415     CI->setCallingConv(Fn->getCallingConv());
416   return CI;
417 }
418 
419 /// EmitFPutS - Emit a call to the puts function.  Str is required to be a
420 /// pointer and File is a pointer to FILE.
421 Value *llvm::EmitFPutS(Value *Str, Value *File, IRBuilder<> &B,
422                        const DataLayout *TD, const TargetLibraryInfo *TLI) {
423   if (!TLI->has(LibFunc::fputs))
424     return nullptr;
425 
426   Module *M = B.GetInsertBlock()->getParent()->getParent();
427   AttributeSet AS[3];
428   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
429   AS[1] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
430   AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
431                             Attribute::NoUnwind);
432   StringRef FPutsName = TLI->getName(LibFunc::fputs);
433   Constant *F;
434   if (File->getType()->isPointerTy())
435     F = M->getOrInsertFunction(FPutsName,
436                                AttributeSet::get(M->getContext(), AS),
437                                B.getInt32Ty(),
438                                B.getInt8PtrTy(),
439                                File->getType(), NULL);
440   else
441     F = M->getOrInsertFunction(FPutsName, B.getInt32Ty(),
442                                B.getInt8PtrTy(),
443                                File->getType(), NULL);
444   CallInst *CI = B.CreateCall2(F, CastToCStr(Str, B), File, "fputs");
445 
446   if (const Function *Fn = dyn_cast<Function>(F->stripPointerCasts()))
447     CI->setCallingConv(Fn->getCallingConv());
448   return CI;
449 }
450 
451 /// EmitFWrite - Emit a call to the fwrite function.  This assumes that Ptr is
452 /// a pointer, Size is an 'intptr_t', and File is a pointer to FILE.
453 Value *llvm::EmitFWrite(Value *Ptr, Value *Size, Value *File,
454                         IRBuilder<> &B, const DataLayout *TD,
455                         const TargetLibraryInfo *TLI) {
456   if (!TLI->has(LibFunc::fwrite))
457     return nullptr;
458 
459   Module *M = B.GetInsertBlock()->getParent()->getParent();
460   AttributeSet AS[3];
461   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
462   AS[1] = AttributeSet::get(M->getContext(), 4, Attribute::NoCapture);
463   AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
464                             Attribute::NoUnwind);
465   LLVMContext &Context = B.GetInsertBlock()->getContext();
466   StringRef FWriteName = TLI->getName(LibFunc::fwrite);
467   Constant *F;
468   if (File->getType()->isPointerTy())
469     F = M->getOrInsertFunction(FWriteName,
470                                AttributeSet::get(M->getContext(), AS),
471                                TD->getIntPtrType(Context),
472                                B.getInt8PtrTy(),
473                                TD->getIntPtrType(Context),
474                                TD->getIntPtrType(Context),
475                                File->getType(), NULL);
476   else
477     F = M->getOrInsertFunction(FWriteName, TD->getIntPtrType(Context),
478                                B.getInt8PtrTy(),
479                                TD->getIntPtrType(Context),
480                                TD->getIntPtrType(Context),
481                                File->getType(), NULL);
482   CallInst *CI = B.CreateCall4(F, CastToCStr(Ptr, B), Size,
483                         ConstantInt::get(TD->getIntPtrType(Context), 1), File);
484 
485   if (const Function *Fn = dyn_cast<Function>(F->stripPointerCasts()))
486     CI->setCallingConv(Fn->getCallingConv());
487   return CI;
488 }
489 
490 SimplifyFortifiedLibCalls::~SimplifyFortifiedLibCalls() { }
491 
492 bool SimplifyFortifiedLibCalls::fold(CallInst *CI, const DataLayout *TD,
493                                      const TargetLibraryInfo *TLI) {
494   // We really need DataLayout for later.
495   if (!TD) return false;
496 
497   this->CI = CI;
498   Function *Callee = CI->getCalledFunction();
499   StringRef Name = Callee->getName();
500   FunctionType *FT = Callee->getFunctionType();
501   LLVMContext &Context = CI->getParent()->getContext();
502   IRBuilder<> B(CI);
503 
504   if (Name == "__memcpy_chk") {
505     // Check if this has the right signature.
506     if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
507         !FT->getParamType(0)->isPointerTy() ||
508         !FT->getParamType(1)->isPointerTy() ||
509         FT->getParamType(2) != TD->getIntPtrType(Context) ||
510         FT->getParamType(3) != TD->getIntPtrType(Context))
511       return false;
512 
513     if (isFoldable(3, 2, false)) {
514       B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
515                      CI->getArgOperand(2), 1);
516       replaceCall(CI->getArgOperand(0));
517       return true;
518     }
519     return false;
520   }
521 
522   // Should be similar to memcpy.
523   if (Name == "__mempcpy_chk") {
524     return false;
525   }
526 
527   if (Name == "__memmove_chk") {
528     // Check if this has the right signature.
529     if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
530         !FT->getParamType(0)->isPointerTy() ||
531         !FT->getParamType(1)->isPointerTy() ||
532         FT->getParamType(2) != TD->getIntPtrType(Context) ||
533         FT->getParamType(3) != TD->getIntPtrType(Context))
534       return false;
535 
536     if (isFoldable(3, 2, false)) {
537       B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
538                       CI->getArgOperand(2), 1);
539       replaceCall(CI->getArgOperand(0));
540       return true;
541     }
542     return false;
543   }
544 
545   if (Name == "__memset_chk") {
546     // Check if this has the right signature.
547     if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
548         !FT->getParamType(0)->isPointerTy() ||
549         !FT->getParamType(1)->isIntegerTy() ||
550         FT->getParamType(2) != TD->getIntPtrType(Context) ||
551         FT->getParamType(3) != TD->getIntPtrType(Context))
552       return false;
553 
554     if (isFoldable(3, 2, false)) {
555       Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(),
556                                    false);
557       B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
558       replaceCall(CI->getArgOperand(0));
559       return true;
560     }
561     return false;
562   }
563 
564   if (Name == "__strcpy_chk" || Name == "__stpcpy_chk") {
565     // Check if this has the right signature.
566     if (FT->getNumParams() != 3 ||
567         FT->getReturnType() != FT->getParamType(0) ||
568         FT->getParamType(0) != FT->getParamType(1) ||
569         FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
570         FT->getParamType(2) != TD->getIntPtrType(Context))
571       return 0;
572 
573 
574     // If a) we don't have any length information, or b) we know this will
575     // fit then just lower to a plain st[rp]cpy. Otherwise we'll keep our
576     // st[rp]cpy_chk call which may fail at runtime if the size is too long.
577     // TODO: It might be nice to get a maximum length out of the possible
578     // string lengths for varying.
579     if (isFoldable(2, 1, true)) {
580       Value *Ret = EmitStrCpy(CI->getArgOperand(0), CI->getArgOperand(1), B, TD,
581                               TLI, Name.substr(2, 6));
582       if (!Ret)
583         return false;
584       replaceCall(Ret);
585       return true;
586     }
587     return false;
588   }
589 
590   if (Name == "__strncpy_chk" || Name == "__stpncpy_chk") {
591     // Check if this has the right signature.
592     if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
593         FT->getParamType(0) != FT->getParamType(1) ||
594         FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
595         !FT->getParamType(2)->isIntegerTy() ||
596         FT->getParamType(3) != TD->getIntPtrType(Context))
597       return false;
598 
599     if (isFoldable(3, 2, false)) {
600       Value *Ret = EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
601                                CI->getArgOperand(2), B, TD, TLI,
602                                Name.substr(2, 7));
603       if (!Ret)
604         return false;
605       replaceCall(Ret);
606       return true;
607     }
608     return false;
609   }
610 
611   if (Name == "__strcat_chk") {
612     return false;
613   }
614 
615   if (Name == "__strncat_chk") {
616     return false;
617   }
618 
619   return false;
620 }
621