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Implement -Wcast-qual, fixing #13772.

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Many thanks to dblaikie for his advices and suggestions!

llvm-svn: 222568
This commit is contained in:
Roman Divacky
2014-11-21 21:03:10 +00:00
parent 6e8e506b3e
commit d517801493
4 changed files with 75 additions and 5 deletions
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44
clang/lib/Sema/SemaCast.cpp
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@@ -142,9 +142,6 @@ namespace {
};
}
static bool CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
bool CheckCVR, bool CheckObjCLifetime);
// The Try functions attempt a specific way of casting. If they succeed, they
// return TC_Success. If their way of casting is not appropriate for the given
// arguments, they return TC_NotApplicable and *may* set diag to a diagnostic
@@ -462,7 +459,10 @@ static bool UnwrapDissimilarPointerTypes(QualType& T1, QualType& T2) {
/// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers.
static bool
CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
bool CheckCVR, bool CheckObjCLifetime) {
bool CheckCVR, bool CheckObjCLifetime,
QualType *TheOffendingSrcType = nullptr,
QualType *TheOffendingDestType = nullptr,
Qualifiers *CastAwayQualifiers = nullptr) {
// If the only checking we care about is for Objective-C lifetime qualifiers,
// and we're not in ARC mode, there's nothing to check.
if (!CheckCVR && CheckObjCLifetime &&
@@ -487,6 +487,8 @@ CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
// Find the qualifiers. We only care about cvr-qualifiers for the
// purpose of this check, because other qualifiers (address spaces,
// Objective-C GC, etc.) are part of the type's identity.
QualType PrevUnwrappedSrcType = UnwrappedSrcType;
QualType PrevUnwrappedDestType = UnwrappedDestType;
while (UnwrapDissimilarPointerTypes(UnwrappedSrcType, UnwrappedDestType)) {
// Determine the relevant qualifiers at this level.
Qualifiers SrcQuals, DestQuals;
@@ -497,6 +499,13 @@ CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
if (CheckCVR) {
RetainedSrcQuals.setCVRQualifiers(SrcQuals.getCVRQualifiers());
RetainedDestQuals.setCVRQualifiers(DestQuals.getCVRQualifiers());
if (RetainedSrcQuals != RetainedDestQuals && TheOffendingSrcType &&
TheOffendingDestType && CastAwayQualifiers) {
*TheOffendingSrcType = PrevUnwrappedSrcType;
*TheOffendingDestType = PrevUnwrappedDestType;
*CastAwayQualifiers = RetainedSrcQuals - RetainedDestQuals;
}
}
if (CheckObjCLifetime &&
@@ -505,6 +514,9 @@ CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
cv1.push_back(RetainedSrcQuals);
cv2.push_back(RetainedDestQuals);
PrevUnwrappedSrcType = UnwrappedSrcType;
PrevUnwrappedDestType = UnwrappedDestType;
}
if (cv1.empty())
return false;
@@ -2371,6 +2383,30 @@ void CastOperation::CheckCStyleCast() {
if (Kind == CK_BitCast)
checkCastAlign();
// -Wcast-qual
QualType TheOffendingSrcType, TheOffendingDestType;
Qualifiers CastAwayQualifiers;
if (SrcType->isAnyPointerType() && DestType->isAnyPointerType() &&
CastsAwayConstness(Self, SrcType, DestType, true, false,
&TheOffendingSrcType, &TheOffendingDestType,
&CastAwayQualifiers)) {
int qualifiers = -1;
if (CastAwayQualifiers.hasConst() && CastAwayQualifiers.hasVolatile()) {
qualifiers = 0;
} else if (CastAwayQualifiers.hasConst()) {
qualifiers = 1;
} else if (CastAwayQualifiers.hasVolatile()) {
qualifiers = 2;
}
// This is a variant of int **x; const int **y = (const int **)x;
if (qualifiers == -1)
Self.Diag(SrcExpr.get()->getLocStart(), diag::warn_cast_qual2) <<
SrcType << DestType;
else
Self.Diag(SrcExpr.get()->getLocStart(), diag::warn_cast_qual) <<
TheOffendingSrcType << TheOffendingDestType << qualifiers;
}
}
ExprResult Sema::BuildCStyleCastExpr(SourceLocation LPLoc,