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