[Sema] Change addr space diagnostics in casts to follow C++ style.
This change adds a new diagnostic for mismatching address spaces
to be used for C++ casts (only enabled in C style cast for now,
the rest will follow!).
The change extends C-style cast rules to account for address spaces.
It also adds a separate function for address space cast checking that
can be used to map from a separate address space cast operator
addrspace_cast (to be added as a follow up patch).
Note, that after this change clang will no longer allows arbitrary
address space conversions in reinterpret_casts because they can lead
to accidental errors. The implicit safe conversions would still be
allowed.
Differential Revision: https://reviews.llvm.org/D58346
llvm-svn: 355609
diff --git a/clang/lib/Sema/SemaCast.cpp b/clang/lib/Sema/SemaCast.cpp
index bfe08cf..ce6481c 100644
--- a/clang/lib/Sema/SemaCast.cpp
+++ b/clang/lib/Sema/SemaCast.cpp
@@ -2212,7 +2212,15 @@
/*CheckObjCLifetime=*/CStyle))
SuccessResult = getCastAwayConstnessCastKind(CACK, msg);
- if (IsLValueCast) {
+ if (IsAddressSpaceConversion(SrcType, DestType)) {
+ Kind = CK_AddressSpaceConversion;
+ assert(SrcType->isPointerType() && DestType->isPointerType());
+ if (!CStyle &&
+ !DestType->getPointeeType().getQualifiers().isAddressSpaceSupersetOf(
+ SrcType->getPointeeType().getQualifiers())) {
+ SuccessResult = TC_Failed;
+ }
+ } else if (IsLValueCast) {
Kind = CK_LValueBitCast;
} else if (DestType->isObjCObjectPointerType()) {
Kind = Self.PrepareCastToObjCObjectPointer(SrcExpr);
@@ -2222,8 +2230,6 @@
} else {
Kind = CK_BitCast;
}
- } else if (IsAddressSpaceConversion(SrcType, DestType)) {
- Kind = CK_AddressSpaceConversion;
} else {
Kind = CK_BitCast;
}
@@ -2278,6 +2284,41 @@
return SuccessResult;
}
+static TryCastResult TryAddressSpaceCast(Sema &Self, ExprResult &SrcExpr,
+ QualType DestType, bool CStyle,
+ unsigned &msg) {
+ if (!Self.getLangOpts().OpenCL)
+ // FIXME: As compiler doesn't have any information about overlapping addr
+ // spaces at the moment we have to be permissive here.
+ return TC_NotApplicable;
+ // Even though the logic below is general enough and can be applied to
+ // non-OpenCL mode too, we fast-path above because no other languages
+ // define overlapping address spaces currently.
+ auto SrcType = SrcExpr.get()->getType();
+ auto SrcPtrType = SrcType->getAs<PointerType>();
+ if (!SrcPtrType)
+ return TC_NotApplicable;
+ auto DestPtrType = DestType->getAs<PointerType>();
+ if (!DestPtrType)
+ return TC_NotApplicable;
+ auto SrcPointeeType = SrcPtrType->getPointeeType();
+ auto DestPointeeType = DestPtrType->getPointeeType();
+ if (SrcPointeeType.getAddressSpace() == DestPointeeType.getAddressSpace())
+ return TC_NotApplicable;
+ if (!DestPtrType->isAddressSpaceOverlapping(*SrcPtrType)) {
+ msg = diag::err_bad_cxx_cast_addr_space_mismatch;
+ return TC_Failed;
+ }
+ auto SrcPointeeTypeWithoutAS =
+ Self.Context.removeAddrSpaceQualType(SrcPointeeType.getCanonicalType());
+ auto DestPointeeTypeWithoutAS =
+ Self.Context.removeAddrSpaceQualType(DestPointeeType.getCanonicalType());
+ return Self.Context.hasSameType(SrcPointeeTypeWithoutAS,
+ DestPointeeTypeWithoutAS)
+ ? TC_Success
+ : TC_NotApplicable;
+}
+
void CastOperation::checkAddressSpaceCast(QualType SrcType, QualType DestType) {
// In OpenCL only conversions between pointers to objects in overlapping
// addr spaces are allowed. v2.0 s6.5.5 - Generic addr space overlaps
@@ -2372,30 +2413,35 @@
// listed above, the interpretation that appears first in the list is used,
// even if a cast resulting from that interpretation is ill-formed.
// In plain language, this means trying a const_cast ...
+ // Note that for address space we check compatibility after const_cast.
unsigned msg = diag::err_bad_cxx_cast_generic;
TryCastResult tcr = TryConstCast(Self, SrcExpr, DestType,
- /*CStyle*/true, msg);
+ /*CStyle*/ true, msg);
if (SrcExpr.isInvalid())
return;
if (isValidCast(tcr))
Kind = CK_NoOp;
- Sema::CheckedConversionKind CCK
- = FunctionalStyle? Sema::CCK_FunctionalCast
- : Sema::CCK_CStyleCast;
+ Sema::CheckedConversionKind CCK =
+ FunctionalStyle ? Sema::CCK_FunctionalCast : Sema::CCK_CStyleCast;
if (tcr == TC_NotApplicable) {
- // ... or if that is not possible, a static_cast, ignoring const, ...
- tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange,
- msg, Kind, BasePath, ListInitialization);
+ tcr = TryAddressSpaceCast(Self, SrcExpr, DestType, /*CStyle*/ true, msg);
if (SrcExpr.isInvalid())
return;
-
if (tcr == TC_NotApplicable) {
- // ... and finally a reinterpret_cast, ignoring const.
- tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/true,
- OpRange, msg, Kind);
+ // ... or if that is not possible, a static_cast, ignoring const, ...
+ tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange, msg, Kind,
+ BasePath, ListInitialization);
if (SrcExpr.isInvalid())
return;
+
+ if (tcr == TC_NotApplicable) {
+ // ... and finally a reinterpret_cast, ignoring const.
+ tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/ true,
+ OpRange, msg, Kind);
+ if (SrcExpr.isInvalid())
+ return;
+ }
}
}
@@ -2426,8 +2472,6 @@
}
}
- checkAddressSpaceCast(SrcExpr.get()->getType(), DestType);
-
if (isValidCast(tcr)) {
if (Kind == CK_BitCast)
checkCastAlign();