Constify GetConstantStringInfo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101298 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-04-14 22:20:45 +00:00
parent 4eb373988e
commit 0a60fa3321
2 changed files with 15 additions and 13 deletions

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@ -122,7 +122,8 @@ namespace llvm {
/// StopAtNul is set to true (the default), the returned string is truncated
/// by a nul character in the global. If StopAtNul is false, the nul
/// character is included in the result string.
bool GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset = 0,
bool GetConstantStringInfo(const Value *V, std::string &Str,
uint64_t Offset = 0,
bool StopAtNul = true);
/// GetStringLength - If we can compute the length of the string pointed to by

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@ -1342,22 +1342,23 @@ Value *llvm::FindInsertedValue(Value *V, const unsigned *idx_begin,
/// GetConstantStringInfo - This function computes the length of a
/// null-terminated C string pointed to by V. If successful, it returns true
/// and returns the string in Str. If unsuccessful, it returns false.
bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset,
bool llvm::GetConstantStringInfo(const Value *V, std::string &Str,
uint64_t Offset,
bool StopAtNul) {
// If V is NULL then return false;
if (V == NULL) return false;
// Look through bitcast instructions.
if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
if (const BitCastInst *BCI = dyn_cast<BitCastInst>(V))
return GetConstantStringInfo(BCI->getOperand(0), Str, Offset, StopAtNul);
// If the value is not a GEP instruction nor a constant expression with a
// GEP instruction, then return false because ConstantArray can't occur
// any other way
User *GEP = 0;
if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
const User *GEP = 0;
if (const GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
GEP = GEPI;
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
} else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
if (CE->getOpcode() == Instruction::BitCast)
return GetConstantStringInfo(CE->getOperand(0), Str, Offset, StopAtNul);
if (CE->getOpcode() != Instruction::GetElementPtr)
@ -1378,7 +1379,7 @@ bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset,
// Check to make sure that the first operand of the GEP is an integer and
// has value 0 so that we are sure we're indexing into the initializer.
ConstantInt *FirstIdx = dyn_cast<ConstantInt>(GEP->getOperand(1));
const ConstantInt *FirstIdx = dyn_cast<ConstantInt>(GEP->getOperand(1));
if (FirstIdx == 0 || !FirstIdx->isZero())
return false;
@ -1386,7 +1387,7 @@ bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset,
// into the array. If this occurs, we can't say anything meaningful about
// the string.
uint64_t StartIdx = 0;
if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
if (const ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
StartIdx = CI->getZExtValue();
else
return false;
@ -1397,10 +1398,10 @@ bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset,
// The GEP instruction, constant or instruction, must reference a global
// variable that is a constant and is initialized. The referenced constant
// initializer is the array that we'll use for optimization.
GlobalVariable* GV = dyn_cast<GlobalVariable>(V);
const GlobalVariable* GV = dyn_cast<GlobalVariable>(V);
if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer())
return false;
Constant *GlobalInit = GV->getInitializer();
const Constant *GlobalInit = GV->getInitializer();
// Handle the ConstantAggregateZero case
if (isa<ConstantAggregateZero>(GlobalInit)) {
@ -1411,7 +1412,7 @@ bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset,
}
// Must be a Constant Array
ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
const ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
if (Array == 0 || !Array->getType()->getElementType()->isIntegerTy(8))
return false;
@ -1425,8 +1426,8 @@ bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset,
// to in the array.
Str.reserve(NumElts-Offset);
for (unsigned i = Offset; i != NumElts; ++i) {
Constant *Elt = Array->getOperand(i);
ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
const Constant *Elt = Array->getOperand(i);
const ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
if (!CI) // This array isn't suitable, non-int initializer.
return false;
if (StopAtNul && CI->isZero())