#include "llvm/Instructions.h"
#include "llvm/GlobalVariable.h"
#include "llvm/IntrinsicInst.h"
-#include "llvm/ADT/DenseMap.h"
+#include "llvm/Target/TargetData.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/MathExtras.h"
-#include "llvm/Target/TargetData.h"
#include <cstring>
using namespace llvm;
return FindInsertedValue(I->getAggregateOperand(), Idxs.begin(), Idxs.end(),
InsertBefore);
}
-
// Otherwise, we don't know (such as, extracting from a function return value
// or load instruction)
return 0;
/// 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.
-const char *llvm::GetConstantStringInfo(Value *V, uint64_t Offset,
- bool StopAtNul) {
- static DenseMap<Value*, std::string> StringInfoMap;
- static DenseMap<Value*, bool> NulMap;
-
- // If we've already determined that the Value is NUL, then return 0.
- if (NulMap[V])
- return 0;
-
- // Check to see if we've already calculated the string info.
- if (StringInfoMap.find(V) != StringInfoMap.end())
- return StringInfoMap.lookup(V).c_str();
-
- // If V is NULL then return nul.
- if (V == 0) {
- NulMap[V] = true;
- return 0;
- }
-
- std::string *Str = &StringInfoMap.FindAndConstruct(V).second;
- Str->clear();
+bool llvm::GetConstantStringInfo(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))
- return GetConstantStringInfo(BCI->getOperand(0), Offset, StopAtNul);
-
+ 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)) {
GEP = GEPI;
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
if (CE->getOpcode() == Instruction::BitCast)
- return GetConstantStringInfo(CE->getOperand(0), Offset, StopAtNul);
-
- if (CE->getOpcode() != Instruction::GetElementPtr) {
- NulMap[V] = true;
- return 0;
- }
-
+ return GetConstantStringInfo(CE->getOperand(0), Str, Offset, StopAtNul);
+ if (CE->getOpcode() != Instruction::GetElementPtr)
+ return false;
GEP = CE;
}
if (GEP) {
// Make sure the GEP has exactly three arguments.
- if (GEP->getNumOperands() != 3) {
- NulMap[V] = true;
- return 0;
- }
-
+ if (GEP->getNumOperands() != 3)
+ return false;
+
// Make sure the index-ee is a pointer to array of i8.
const PointerType *PT = cast<PointerType>(GEP->getOperand(0)->getType());
const ArrayType *AT = dyn_cast<ArrayType>(PT->getElementType());
- if (AT == 0 || AT->getElementType() != Type::Int8Ty) {
- NulMap[V] = true;
- return 0;
- }
+ if (AT == 0 || AT->getElementType() != Type::Int8Ty)
+ return false;
// 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));
- if (FirstIdx == 0 || !FirstIdx->isZero()) {
- NulMap[V] = true;
- return 0;
- }
+ if (FirstIdx == 0 || !FirstIdx->isZero())
+ return false;
// If the second index isn't a ConstantInt, then this is a variable index
// 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 (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
StartIdx = CI->getZExtValue();
- } else {
- NulMap[V] = true;
- return 0;
- }
-
- return GetConstantStringInfo(GEP->getOperand(0), StartIdx + Offset,
+ else
+ return false;
+ return GetConstantStringInfo(GEP->getOperand(0), Str, StartIdx+Offset,
StopAtNul);
}
// 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);
- if (!GV || !GV->isConstant() || !GV->hasInitializer()) {
- NulMap[V] = true;
- return 0;
- }
+ if (!GV || !GV->isConstant() || !GV->hasInitializer())
+ return false;
Constant *GlobalInit = GV->getInitializer();
// Handle the ConstantAggregateZero case
- if (isa<ConstantAggregateZero>(GlobalInit))
+ if (isa<ConstantAggregateZero>(GlobalInit)) {
// This is a degenerate case. The initializer is constant zero so the
// length of the string must be zero.
- return "";
+ Str.clear();
+ return true;
+ }
// Must be a Constant Array
ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
- if (Array == 0 || Array->getType()->getElementType() != Type::Int8Ty) {
- NulMap[V] = true;
- return 0;
- }
+ if (Array == 0 || Array->getType()->getElementType() != Type::Int8Ty)
+ return false;
// Get the number of elements in the array
uint64_t NumElts = Array->getType()->getNumElements();
- if (Offset > NumElts) {
- NulMap[V] = true;
- return 0;
- }
+ if (Offset > NumElts)
+ return false;
// Traverse the constant array from 'Offset' which is the place the GEP refers
// to in the array.
- Str->reserve(NumElts - Offset);
-
+ Str.reserve(NumElts-Offset);
for (unsigned i = Offset; i != NumElts; ++i) {
Constant *Elt = Array->getOperand(i);
ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
-
- if (!CI) { // This array isn't suitable, non-int initializer.
- StringInfoMap.erase(V);
- NulMap[V] = true;
- return 0;
- }
-
+ if (!CI) // This array isn't suitable, non-int initializer.
+ return false;
if (StopAtNul && CI->isZero())
- return Str->c_str(); // we found end of string, success!
-
- Str->operator+=((char)CI->getZExtValue());
+ return true; // we found end of string, success!
+ Str += (char)CI->getZExtValue();
}
-
+
// The array isn't null terminated, but maybe this is a memcpy, not a strcpy.
- return Str->c_str();
+ return true;
}
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