[SimplifyLibCalls] Fold more fortified functions into non-fortified variants

When the object size argument is -1, no checking can be done, so calling the
_chk variant is unnecessary. We already did this for a bunch of these
functions.

rdar://50797197

Differential revision: https://reviews.llvm.org/D62358

llvm-svn: 362272

1 files changed, 132 insertions, 15 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index f5e3d76faa0..0c95f4ce485 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -2825,12 +2825,23 @@ void LibCallSimplifier::eraseFromParent(Instruction *I) {
 // Fortified Library Call Optimizations
 //===----------------------------------------------------------------------===//
 
-bool FortifiedLibCallSimplifier::isFortifiedCallFoldable(CallInst *CI,
-                                                         unsigned ObjSizeOp,
-                                                         unsigned SizeOp,
-                                                         bool isString) {
-  if (CI->getArgOperand(ObjSizeOp) == CI->getArgOperand(SizeOp))
+bool
+FortifiedLibCallSimplifier::isFortifiedCallFoldable(CallInst *CI,
+                                                    unsigned ObjSizeOp,
+                                                    Optional<unsigned> SizeOp,
+                                                    Optional<unsigned> StrOp,
+                                                    Optional<unsigned> FlagOp) {
+  // If this function takes a flag argument, the implementation may use it to
+  // perform extra checks. Don't fold into the non-checking variant.
+  if (FlagOp) {
+    ConstantInt *Flag = dyn_cast<ConstantInt>(CI->getArgOperand(*FlagOp));
+    if (!Flag || !Flag->isZero())
+      return false;
+  }
+
+  if (SizeOp && CI->getArgOperand(ObjSizeOp) == CI->getArgOperand(*SizeOp))
     return true;
+
   if (ConstantInt *ObjSizeCI =
           dyn_cast<ConstantInt>(CI->getArgOperand(ObjSizeOp))) {
     if (ObjSizeCI->isMinusOne())
@@ -2838,23 +2849,27 @@ bool FortifiedLibCallSimplifier::isFortifiedCallFoldable(CallInst *CI,
     // If the object size wasn't -1 (unknown), bail out if we were asked to.
     if (OnlyLowerUnknownSize)
       return false;
-    if (isString) {
-      uint64_t Len = GetStringLength(CI->getArgOperand(SizeOp));
+    if (StrOp) {
+      uint64_t Len = GetStringLength(CI->getArgOperand(*StrOp));
       // If the length is 0 we don't know how long it is and so we can't
       // remove the check.
       if (Len == 0)
         return false;
       return ObjSizeCI->getZExtValue() >= Len;
     }
-    if (ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getArgOperand(SizeOp)))
-      return ObjSizeCI->getZExtValue() >= SizeCI->getZExtValue();
+
+    if (SizeOp) {
+      if (ConstantInt *SizeCI =
+              dyn_cast<ConstantInt>(CI->getArgOperand(*SizeOp)))
+        return ObjSizeCI->getZExtValue() >= SizeCI->getZExtValue();
+    }
   }
   return false;
 }
 
 Value *FortifiedLibCallSimplifier::optimizeMemCpyChk(CallInst *CI,
                                                      IRBuilder<> &B) {
-  if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+  if (isFortifiedCallFoldable(CI, 3, 2)) {
     B.CreateMemCpy(CI->getArgOperand(0), 1, CI->getArgOperand(1), 1,
                    CI->getArgOperand(2));
     return CI->getArgOperand(0);
@@ -2864,7 +2879,7 @@ Value *FortifiedLibCallSimplifier::optimizeMemCpyChk(CallInst *CI,
 
 Value *FortifiedLibCallSimplifier::optimizeMemMoveChk(CallInst *CI,
                                                       IRBuilder<> &B) {
-  if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+  if (isFortifiedCallFoldable(CI, 3, 2)) {
     B.CreateMemMove(CI->getArgOperand(0), 1, CI->getArgOperand(1), 1,
                     CI->getArgOperand(2));
     return CI->getArgOperand(0);
@@ -2876,7 +2891,7 @@ Value *FortifiedLibCallSimplifier::optimizeMemSetChk(CallInst *CI,
                                                      IRBuilder<> &B) {
   // TODO: Try foldMallocMemset() here.
 
-  if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+  if (isFortifiedCallFoldable(CI, 3, 2)) {
     Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
     B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
     return CI->getArgOperand(0);
@@ -2902,7 +2917,7 @@ Value *FortifiedLibCallSimplifier::optimizeStrpCpyChk(CallInst *CI,
   // st[rp]cpy_chk call which may fail at runtime if the size is too long.
   // TODO: It might be nice to get a maximum length out of the possible
   // string lengths for varying.
-  if (isFortifiedCallFoldable(CI, 2, 1, true)) {
+  if (isFortifiedCallFoldable(CI, 2, None, 1)) {
     if (Func == LibFunc_strcpy_chk)
       return emitStrCpy(Dst, Src, B, TLI);
     else
@@ -2930,10 +2945,10 @@ Value *FortifiedLibCallSimplifier::optimizeStrpCpyChk(CallInst *CI,
 Value *FortifiedLibCallSimplifier::optimizeStrpNCpyChk(CallInst *CI,
                                                        IRBuilder<> &B,
                                                        LibFunc Func) {
-  if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+  if (isFortifiedCallFoldable(CI, 3, 2)) {
     if (Func == LibFunc_strncpy_chk)
       return emitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
-                         CI->getArgOperand(2), B, TLI);
+                               CI->getArgOperand(2), B, TLI);
     else
       return emitStpNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
                          CI->getArgOperand(2), B, TLI);
@@ -2942,6 +2957,90 @@ Value *FortifiedLibCallSimplifier::optimizeStrpNCpyChk(CallInst *CI,
   return nullptr;
 }
 
+Value *FortifiedLibCallSimplifier::optimizeMemCCpyChk(CallInst *CI,
+                                                      IRBuilder<> &B) {
+  if (isFortifiedCallFoldable(CI, 4, 3))
+    return emitMemCCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+                       CI->getArgOperand(2), CI->getArgOperand(3), B, TLI);
+
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeSNPrintfChk(CallInst *CI,
+                                                       IRBuilder<> &B) {
+  if (isFortifiedCallFoldable(CI, 3, 1, None, 2)) {
+    SmallVector<Value *, 8> VariadicArgs(CI->arg_begin() + 5, CI->arg_end());
+    return emitSNPrintf(CI->getArgOperand(0), CI->getArgOperand(1),
+                        CI->getArgOperand(4), VariadicArgs, B, TLI);
+  }
+
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeSPrintfChk(CallInst *CI,
+                                                      IRBuilder<> &B) {
+  if (isFortifiedCallFoldable(CI, 2, None, None, 1)) {
+    SmallVector<Value *, 8> VariadicArgs(CI->arg_begin() + 4, CI->arg_end());
+    return emitSPrintf(CI->getArgOperand(0), CI->getArgOperand(3), VariadicArgs,
+                       B, TLI);
+  }
+
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeStrCatChk(CallInst *CI,
+                                                     IRBuilder<> &B) {
+  if (isFortifiedCallFoldable(CI, 2))
+    return emitStrCat(CI->getArgOperand(0), CI->getArgOperand(1), B, TLI);
+
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeStrLCat(CallInst *CI,
+                                                   IRBuilder<> &B) {
+  if (isFortifiedCallFoldable(CI, 3))
+    return emitStrLCat(CI->getArgOperand(0), CI->getArgOperand(1),
+                       CI->getArgOperand(2), B, TLI);
+
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeStrNCatChk(CallInst *CI,
+                                                      IRBuilder<> &B) {
+  if (isFortifiedCallFoldable(CI, 3))
+    return emitStrNCat(CI->getArgOperand(0), CI->getArgOperand(1),
+                       CI->getArgOperand(2), B, TLI);
+
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeStrLCpyChk(CallInst *CI,
+                                                      IRBuilder<> &B) {
+  if (isFortifiedCallFoldable(CI, 3))
+    return emitStrLCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+                       CI->getArgOperand(2), B, TLI);
+
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeVSNPrintfChk(CallInst *CI,
+                                                        IRBuilder<> &B) {
+  if (isFortifiedCallFoldable(CI, 3, 1, None, 2))
+    return emitVSNPrintf(CI->getArgOperand(0), CI->getArgOperand(1),
+                         CI->getArgOperand(4), CI->getArgOperand(5), B, TLI);
+
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeVSPrintfChk(CallInst *CI,
+                                                       IRBuilder<> &B) {
+  if (isFortifiedCallFoldable(CI, 2, None, None, 1))
+    return emitVSPrintf(CI->getArgOperand(0), CI->getArgOperand(3),
+                        CI->getArgOperand(4), B, TLI);
+
+  return nullptr;
+}
+
 Value *FortifiedLibCallSimplifier::optimizeCall(CallInst *CI) {
   // FIXME: We shouldn't be changing "nobuiltin" or TLI unavailable calls here.
   // Some clang users checked for _chk libcall availability using:
@@ -2986,6 +3085,24 @@ Value *FortifiedLibCallSimplifier::optimizeCall(CallInst *CI) {
   case LibFunc_stpncpy_chk:
   case LibFunc_strncpy_chk:
     return optimizeStrpNCpyChk(CI, Builder, Func);
+  case LibFunc_memccpy_chk:
+    return optimizeMemCCpyChk(CI, Builder);
+  case LibFunc_snprintf_chk:
+    return optimizeSNPrintfChk(CI, Builder);
+  case LibFunc_sprintf_chk:
+    return optimizeSPrintfChk(CI, Builder);
+  case LibFunc_strcat_chk:
+    return optimizeStrCatChk(CI, Builder);
+  case LibFunc_strlcat_chk:
+    return optimizeStrLCat(CI, Builder);
+  case LibFunc_strncat_chk:
+    return optimizeStrNCatChk(CI, Builder);
+  case LibFunc_strlcpy_chk:
+    return optimizeStrLCpyChk(CI, Builder);
+  case LibFunc_vsnprintf_chk:
+    return optimizeVSNPrintfChk(CI, Builder);
+  case LibFunc_vsprintf_chk:
+    return optimizeVSPrintfChk(CI, Builder);
   default:
     break;
   }