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author | Eric Christopher <echristo@apple.com> | 2010-02-02 22:10:43 +0000 |
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committer | Eric Christopher <echristo@apple.com> | 2010-02-02 22:10:43 +0000 |
commit | a6a089cd244033109a232c99cb09ac424703afff (patch) | |
tree | 00ebc1b3f91ed2385c814e9d706980b2a4563d34 /lib/Transforms | |
parent | 7f89fdae34a11f8b0b3e0ee1de3f2f6d317f38c4 (diff) | |
download | external_llvm-a6a089cd244033109a232c99cb09ac424703afff.zip external_llvm-a6a089cd244033109a232c99cb09ac424703afff.tar.gz external_llvm-a6a089cd244033109a232c99cb09ac424703afff.tar.bz2 |
Re-add strcmp and known size object size checking optimization.
Passed bootstrap and nightly test run here.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95145 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms')
-rw-r--r-- | lib/Transforms/InstCombine/InstCombineCalls.cpp | 44 | ||||
-rw-r--r-- | lib/Transforms/Scalar/SimplifyLibCalls.cpp | 9 |
2 files changed, 41 insertions, 12 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp index 5de846e..d49f3b5 100644 --- a/lib/Transforms/InstCombine/InstCombineCalls.cpp +++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp @@ -633,16 +633,40 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) { break; } case Intrinsic::objectsize: { - ConstantInt *Const = cast<ConstantInt>(II->getOperand(2)); - const Type *Ty = CI.getType(); - - // 0 is maximum number of bytes left, 1 is minimum number of bytes left. - // TODO: actually add these values, the current return values are "don't - // know". - if (Const->getZExtValue() == 0) - return ReplaceInstUsesWith(CI, Constant::getAllOnesValue(Ty)); - else - return ReplaceInstUsesWith(CI, ConstantInt::get(Ty, 0)); + const Type *ReturnTy = CI.getType(); + Value *Op1 = II->getOperand(1); + + // If we're a constant expr then we just return the number of bytes + // left in whatever we're indexing. Since it's constant there's no + // need for maximum or minimum bytes. + if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op1)) { + // If this isn't a GEP give up. + if (CE->getOpcode() != Instruction::GetElementPtr) return 0; + + const PointerType *ObjTy = + reinterpret_cast<const PointerType*>(CE->getOperand(0)->getType()); + + if (const ArrayType *AT = dyn_cast<ArrayType>(ObjTy->getElementType())) { + + // Deal with multi-dimensional arrays + const ArrayType *SAT = AT; + while ((AT = dyn_cast<ArrayType>(AT->getElementType()))) + SAT = AT; + + size_t numElems = SAT->getNumElements(); + // We return the remaining bytes, so grab the size of an element + // in bytes. + size_t sizeofElem = SAT->getElementType()->getPrimitiveSizeInBits() / 8; + + ConstantInt *Const = + cast<ConstantInt>(CE->getOperand(CE->getNumOperands() - 1)); + size_t indx = Const->getZExtValue(); + return ReplaceInstUsesWith(CI, + ConstantInt::get(ReturnTy, + ((numElems - indx) * sizeofElem))); + } + } + // TODO: Add more types here. } } diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp index db6ff29..4216e8f 100644 --- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp +++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp @@ -1213,8 +1213,13 @@ struct StrCpyChkOpt : public LibCallOptimization { if (!SizeCI) return 0; - // We don't have any length information, just lower to a plain strcpy. - if (SizeCI->isAllOnesValue()) + // If a) we don't have any length information, or b) we know this will + // fit then just lower to a plain strcpy. Otherwise we'll keep our + // strcpy_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 (SizeCI->isAllOnesValue() || + SizeCI->getZExtValue() >= GetStringLength(CI->getOperand(2))) return EmitStrCpy(CI->getOperand(1), CI->getOperand(2), B); return 0; |