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[analyzer] Change large if body to early return. No functionality change. 

llvm-svn: 132956
This commit is contained in:
Jordy Rose 2011-06-14 01:26:48 +00:00
parent d359289669
commit 45d8c12b68
1 changed files with 74 additions and 73 deletions
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147
clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
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@ -934,92 +934,93 @@ void CStringChecker::evalstrLengthCommon(CheckerContext &C, const CallExpr *CE,
state = checkNonNull(C, state, Arg, ArgVal);
if (state) {
SVal strLength = getCStringLength(C, state, Arg, ArgVal);
if (!state)
return;
// If the argument isn't a valid C string, there's no valid state to
// transition to.
if (strLength.isUndef())
return;
SVal strLength = getCStringLength(C, state, Arg, ArgVal);
DefinedOrUnknownSVal result = UnknownVal();
// If the argument isn't a valid C string, there's no valid state to
// transition to.
if (strLength.isUndef())
return;
// If the check is for strnlen() then bind the return value to no more than
// the maxlen value.
if (IsStrnlen) {
QualType cmpTy = C.getSValBuilder().getContext().IntTy;
DefinedOrUnknownSVal result = UnknownVal();
// It's a little unfortunate to be getting this again,
// but it's not that expensive...
const Expr *maxlenExpr = CE->getArg(1);
SVal maxlenVal = state->getSVal(maxlenExpr);
// If the check is for strnlen() then bind the return value to no more than
// the maxlen value.
if (IsStrnlen) {
QualType cmpTy = C.getSValBuilder().getContext().IntTy;
NonLoc *strLengthNL = dyn_cast<NonLoc>(&strLength);
NonLoc *maxlenValNL = dyn_cast<NonLoc>(&maxlenVal);
// It's a little unfortunate to be getting this again,
// but it's not that expensive...
const Expr *maxlenExpr = CE->getArg(1);
SVal maxlenVal = state->getSVal(maxlenExpr);
if (strLengthNL && maxlenValNL) {
const GRState *stateStringTooLong, *stateStringNotTooLong;
NonLoc *strLengthNL = dyn_cast<NonLoc>(&strLength);
NonLoc *maxlenValNL = dyn_cast<NonLoc>(&maxlenVal);
// Check if the strLength is greater than the maxlen.
llvm::tie(stateStringTooLong, stateStringNotTooLong) =
state->assume(cast<DefinedOrUnknownSVal>
(C.getSValBuilder().evalBinOpNN(state, BO_GT,
*strLengthNL,
*maxlenValNL,
cmpTy)));
if (strLengthNL && maxlenValNL) {
const GRState *stateStringTooLong, *stateStringNotTooLong;
if (stateStringTooLong && !stateStringNotTooLong) {
// If the string is longer than maxlen, return maxlen.
result = *maxlenValNL;
} else if (stateStringNotTooLong && !stateStringTooLong) {
// If the string is shorter than maxlen, return its length.
result = *strLengthNL;
}
}
// Check if the strLength is greater than the maxlen.
llvm::tie(stateStringTooLong, stateStringNotTooLong) =
state->assume(cast<DefinedOrUnknownSVal>
(C.getSValBuilder().evalBinOpNN(state, BO_GT,
*strLengthNL,
*maxlenValNL,
cmpTy)));
if (result.isUnknown()) {
// If we don't have enough information for a comparison, there's
// no guarantee the full string length will actually be returned.
// All we know is the return value is the min of the string length
// and the limit. This is better than nothing.
unsigned Count = C.getNodeBuilder().getCurrentBlockCount();
result = C.getSValBuilder().getConjuredSymbolVal(NULL, CE, Count);
NonLoc *resultNL = cast<NonLoc>(&result);
if (strLengthNL) {
state = state->assume(cast<DefinedOrUnknownSVal>
(C.getSValBuilder().evalBinOpNN(state, BO_LE,
*resultNL,
*strLengthNL,
cmpTy)), true);
}
if (maxlenValNL) {
state = state->assume(cast<DefinedOrUnknownSVal>
(C.getSValBuilder().evalBinOpNN(state, BO_LE,
*resultNL,
*maxlenValNL,
cmpTy)), true);
}
}
} else {
// This is a plain strlen(), not strnlen().
result = cast<DefinedOrUnknownSVal>(strLength);
// If we don't know the length of the string, conjure a return
// value, so it can be used in constraints, at least.
if (result.isUnknown()) {
unsigned Count = C.getNodeBuilder().getCurrentBlockCount();
result = C.getSValBuilder().getConjuredSymbolVal(NULL, CE, Count);
if (stateStringTooLong && !stateStringNotTooLong) {
// If the string is longer than maxlen, return maxlen.
result = *maxlenValNL;
} else if (stateStringNotTooLong && !stateStringTooLong) {
// If the string is shorter than maxlen, return its length.
result = *strLengthNL;
}
}
// Bind the return value.
assert(!result.isUnknown() && "Should have conjured a value by now");
state = state->BindExpr(CE, result);
C.addTransition(state);
if (result.isUnknown()) {
// If we don't have enough information for a comparison, there's
// no guarantee the full string length will actually be returned.
// All we know is the return value is the min of the string length
// and the limit. This is better than nothing.
unsigned Count = C.getNodeBuilder().getCurrentBlockCount();
result = C.getSValBuilder().getConjuredSymbolVal(NULL, CE, Count);
NonLoc *resultNL = cast<NonLoc>(&result);
if (strLengthNL) {
state = state->assume(cast<DefinedOrUnknownSVal>
(C.getSValBuilder().evalBinOpNN(state, BO_LE,
*resultNL,
*strLengthNL,
cmpTy)), true);
}
if (maxlenValNL) {
state = state->assume(cast<DefinedOrUnknownSVal>
(C.getSValBuilder().evalBinOpNN(state, BO_LE,
*resultNL,
*maxlenValNL,
cmpTy)), true);
}
}
} else {
// This is a plain strlen(), not strnlen().
result = cast<DefinedOrUnknownSVal>(strLength);
// If we don't know the length of the string, conjure a return
// value, so it can be used in constraints, at least.
if (result.isUnknown()) {
unsigned Count = C.getNodeBuilder().getCurrentBlockCount();
result = C.getSValBuilder().getConjuredSymbolVal(NULL, CE, Count);
}
}
// Bind the return value.
assert(!result.isUnknown() && "Should have conjured a value by now");
state = state->BindExpr(CE, result);
C.addTransition(state);
}
void CStringChecker::evalStrcpy(CheckerContext &C, const CallExpr *CE) const {