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authorBill Wendling <isanbard@gmail.com>2009-03-13 04:37:11 +0000
committerBill Wendling <isanbard@gmail.com>2009-03-13 04:37:11 +0000
commitec6ffc713f5f6e584debda7c55e1b37652e63617 (patch)
treedb612124a57fb8f23dfadbf625ea75d22512bc18 /lib/Analysis/ValueTracking.cpp
parent3ae9248f01596e1fb2f71504217e967c83955621 (diff)
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external_llvm-ec6ffc713f5f6e584debda7c55e1b37652e63617.tar.gz
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Temporarily XFAIL this test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66866 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/ValueTracking.cpp')
-rw-r--r--lib/Analysis/ValueTracking.cpp120
1 files changed, 82 insertions, 38 deletions
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index 20fa69e..d3a7d1b 100644
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -17,9 +17,10 @@
#include "llvm/Instructions.h"
#include "llvm/GlobalVariable.h"
#include "llvm/IntrinsicInst.h"
-#include "llvm/Target/TargetData.h"
+#include "llvm/ADT/DenseMap.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/MathExtras.h"
+#include "llvm/Target/TargetData.h"
#include <cstring>
using namespace llvm;
@@ -928,6 +929,7 @@ Value *llvm::FindInsertedValue(Value *V, const unsigned *idx_begin,
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;
@@ -936,55 +938,86 @@ 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 StopAtNul) {
- // If V is NULL then return false;
- if (V == NULL) return 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();
// Look through bitcast instructions.
if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
- return GetConstantStringInfo(BCI->getOperand(0), Str, Offset, StopAtNul);
-
+ return GetConstantStringInfo(BCI->getOperand(0), 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), Str, Offset, StopAtNul);
- if (CE->getOpcode() != Instruction::GetElementPtr)
- return false;
+ return GetConstantStringInfo(CE->getOperand(0), Offset, StopAtNul);
+
+ if (CE->getOpcode() != Instruction::GetElementPtr) {
+ NulMap[V] = true;
+ return 0;
+ }
+
GEP = CE;
}
if (GEP) {
// Make sure the GEP has exactly three arguments.
- if (GEP->getNumOperands() != 3)
- return false;
-
+ if (GEP->getNumOperands() != 3) {
+ NulMap[V] = true;
+ return 0;
+ }
+
// 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)
- return false;
+ if (AT == 0 || AT->getElementType() != Type::Int8Ty) {
+ NulMap[V] = true;
+ return 0;
+ }
// 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())
- return false;
+ if (FirstIdx == 0 || !FirstIdx->isZero()) {
+ NulMap[V] = true;
+ return 0;
+ }
// 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
- return false;
- return GetConstantStringInfo(GEP->getOperand(0), Str, StartIdx+Offset,
+ } else {
+ NulMap[V] = true;
+ return 0;
+ }
+
+ return GetConstantStringInfo(GEP->getOperand(0), StartIdx + Offset,
StopAtNul);
}
@@ -992,42 +1025,53 @@ bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset,
// 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())
- return false;
+ if (!GV || !GV->isConstant() || !GV->hasInitializer()) {
+ NulMap[V] = true;
+ return 0;
+ }
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.
- Str.clear();
- return true;
- }
+ return "";
// Must be a Constant Array
ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
- if (Array == 0 || Array->getType()->getElementType() != Type::Int8Ty)
- return false;
+ if (Array == 0 || Array->getType()->getElementType() != Type::Int8Ty) {
+ NulMap[V] = true;
+ return 0;
+ }
// Get the number of elements in the array
uint64_t NumElts = Array->getType()->getNumElements();
- if (Offset > NumElts)
- return false;
+ if (Offset > NumElts) {
+ NulMap[V] = true;
+ return 0;
+ }
// 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.
- return false;
+
+ if (!CI) { // This array isn't suitable, non-int initializer.
+ StringInfoMap.erase(V);
+ NulMap[V] = true;
+ return 0;
+ }
+
if (StopAtNul && CI->isZero())
- return true; // we found end of string, success!
- Str += (char)CI->getZExtValue();
+ return Str->c_str(); // we found end of string, success!
+
+ Str->operator+=((char)CI->getZExtValue());
}
-
+
// The array isn't null terminated, but maybe this is a memcpy, not a strcpy.
- return true;
+ return Str->c_str();
}
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