r222568 - Implement -Wcast-qual, fixing #13772.
Roman Divacky
rdivacky at freebsd.org
Fri Nov 21 13:03:11 PST 2014
Author: rdivacky
Date: Fri Nov 21 15:03:10 2014
New Revision: 222568
URL: http://llvm.org/viewvc/llvm-project?rev=222568&view=rev
Log:
Implement -Wcast-qual, fixing #13772.
Many thanks to dblaikie for his advices and suggestions!
Added:
cfe/trunk/test/Sema/warn-cast-qual.c
Modified:
cfe/trunk/include/clang/Basic/DiagnosticGroups.td
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaCast.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=222568&r1=222567&r2=222568&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Fri Nov 21 15:03:10 2014
@@ -60,7 +60,7 @@ def ExternCCompat : DiagGroup<"extern-c-
def KeywordCompat : DiagGroup<"keyword-compat">;
def GNUCaseRange : DiagGroup<"gnu-case-range">;
def CastAlign : DiagGroup<"cast-align">;
-def : DiagGroup<"cast-qual">;
+def CastQual : DiagGroup<"cast-qual">;
def : DiagGroup<"char-align">;
def Comment : DiagGroup<"comment">;
def GNUComplexInteger : DiagGroup<"gnu-complex-integer">;
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=222568&r1=222567&r2=222568&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri Nov 21 15:03:10 2014
@@ -6115,6 +6115,11 @@ def warn_zero_size_struct_union_compat :
def warn_zero_size_struct_union_in_extern_c : Warning<"%select{|empty }0"
"%select{struct|union}1 has size 0 in C, %select{size 1|non-zero size}2 in C++">,
InGroup<ExternCCompat>;
+def warn_cast_qual : Warning<"cast from %0 to %1 drops %select{const and "
+ "volatile qualifiers|const qualifier|volatile qualifier}2">,
+ InGroup<CastQual>, DefaultIgnore;
+def warn_cast_qual2 : Warning<"cast from %0 to %1 must have all intermediate "
+ "pointers const qualified to be safe">, InGroup<CastQual>, DefaultIgnore;
} // End of general sema category.
// inline asm.
Modified: cfe/trunk/lib/Sema/SemaCast.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaCast.cpp?rev=222568&r1=222567&r2=222568&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaCast.cpp (original)
+++ cfe/trunk/lib/Sema/SemaCast.cpp Fri Nov 21 15:03:10 2014
@@ -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
/// \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
// 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
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
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,
Added: cfe/trunk/test/Sema/warn-cast-qual.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-cast-qual.c?rev=222568&view=auto
==============================================================================
--- cfe/trunk/test/Sema/warn-cast-qual.c (added)
+++ cfe/trunk/test/Sema/warn-cast-qual.c Fri Nov 21 15:03:10 2014
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -Wcast-qual -verify %s
+
+#include <stdint.h>
+
+void foo() {
+ const char * const ptr = 0;
+ const char * const *ptrptr = 0;
+ char *y = (char *)ptr; // expected-warning {{cast from 'const char *' to 'char *' drops const qualifier}}
+ char **y1 = (char **)ptrptr; // expected-warning {{cast from 'const char *const' to 'char *' drops const qualifier}}
+ const char **y2 = (const char **)ptrptr; // expected-warning {{cast from 'const char *const *' to 'const char **' drops const qualifier}}
+
+ char *z = (char *)(uintptr_t)(const void *)ptr; // no warning
+ char *z1 = (char *)(const void *)ptr; // expected-warning {{cast from 'const void *' to 'char *' drops const qualifier}}
+
+ volatile char *vol = 0;
+ char *vol2 = (char *)vol; // expected-warning {{cast from 'volatile char *' to 'char *' drops volatile qualifier}}
+ const volatile char *volc = 0;
+ char *volc2 = (char *)volc; // expected-warning {{cast from 'const volatile char *' to 'char *' drops const and volatile qualifiers}}
+
+ int **intptrptr;
+ const int **intptrptrc = (const int **)intptrptr; // expected-warning {{cast from 'int **' to 'const int **' must have all intermediate pointers const qualified}}
+ volatile int **intptrptrv = (volatile int **)intptrptr; // expected-warning {{cast from 'int **' to 'volatile int **' must have all intermediate pointers const qualified}}
+
+ int *intptr;
+ const int *intptrc = (const int *)intptr; // no warning
+
+ const char **charptrptrc;
+ char **charptrptr = (char **)charptrptrc; // expected-warning {{cast from 'const char *' to 'char *' drops const qualifier}}
+}
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