rnk created this revision.
rnk added a reviewer: rsmith.
This fixes a flaw in our AST: PR27098
MSVC always gives plain enums the underlying type 'int'. Clang does this
as well, but we claim the enum is "fixed", as if the user actually wrote
': int'. It means we end up emitting spurious -Wsign-compare warnings on
code like this:
enum Vals { E1, E2, E3 };
bool f(unsigned v1, Vals v2) {
return v1 == v2;
}
We think 'v2' can take on negative values because we think 'Vals' is
fixed. This fixes that.
https://reviews.llvm.org/D43110
Files:
clang/include/clang/AST/Decl.h
clang/include/clang/Sema/Sema.h
clang/lib/AST/Type.cpp
clang/lib/Sema/SemaDecl.cpp
clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
Index: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1040,8 +1040,7 @@
SemaRef.SubstType(TI->getType(), TemplateArgs,
UnderlyingLoc, DeclarationName());
SemaRef.CheckEnumRedeclaration(Def->getLocation(), Def->isScoped(),
- DefnUnderlying,
- /*EnumUnderlyingIsImplicit=*/false, Enum);
+ DefnUnderlying, /*IsFixed=*/true, Enum);
}
}
Index: clang/lib/Sema/SemaDecl.cpp
===================================================================
--- clang/lib/Sema/SemaDecl.cpp
+++ clang/lib/Sema/SemaDecl.cpp
@@ -13236,11 +13236,9 @@
/// Check whether this is a valid redeclaration of a previous enumeration.
/// \return true if the redeclaration was invalid.
-bool Sema::CheckEnumRedeclaration(
- SourceLocation EnumLoc, bool IsScoped, QualType EnumUnderlyingTy,
- bool EnumUnderlyingIsImplicit, const EnumDecl *Prev) {
- bool IsFixed = !EnumUnderlyingTy.isNull();
-
+bool Sema::CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
+ QualType EnumUnderlyingTy, bool IsFixed,
+ const EnumDecl *Prev) {
if (IsScoped != Prev->isScoped()) {
Diag(EnumLoc, diag::err_enum_redeclare_scoped_mismatch)
<< Prev->isScoped();
@@ -13260,10 +13258,6 @@
<< Prev->getIntegerTypeRange();
return true;
}
- } else if (IsFixed && !Prev->isFixed() && EnumUnderlyingIsImplicit) {
- ;
- } else if (!IsFixed && Prev->isFixed() && !Prev->getIntegerTypeSourceInfo()) {
- ;
} else if (IsFixed != Prev->isFixed()) {
Diag(EnumLoc, diag::err_enum_redeclare_fixed_mismatch)
<< Prev->isFixed();
@@ -13559,14 +13553,14 @@
// this early, because it's needed to detect if this is an incompatible
// redeclaration.
llvm::PointerUnion<const Type*, TypeSourceInfo*> EnumUnderlying;
- bool EnumUnderlyingIsImplicit = false;
+ bool IsFixed = !UnderlyingType.isUnset() || ScopedEnum;
if (Kind == TTK_Enum) {
- if (UnderlyingType.isInvalid() || (!UnderlyingType.get() && ScopedEnum))
+ if (UnderlyingType.isInvalid() || (!UnderlyingType.get() && ScopedEnum)) {
// No underlying type explicitly specified, or we failed to parse the
// type, default to int.
EnumUnderlying = Context.IntTy.getTypePtr();
- else if (UnderlyingType.get()) {
+ } else if (UnderlyingType.get()) {
// C++0x 7.2p2: The type-specifier-seq of an enum-base shall name an
// integral type; any cv-qualification is ignored.
TypeSourceInfo *TI = nullptr;
@@ -13585,7 +13579,6 @@
if (getLangOpts().MSVCCompat || TUK == TUK_Definition) {
// Microsoft enums are always of int type.
EnumUnderlying = Context.IntTy.getTypePtr();
- EnumUnderlyingIsImplicit = true;
}
}
}
@@ -13612,8 +13605,7 @@
if (Kind == TTK_Enum) {
New = EnumDecl::Create(Context, SearchDC, KWLoc, Loc, Name, nullptr,
- ScopedEnum, ScopedEnumUsesClassTag,
- !EnumUnderlying.isNull());
+ ScopedEnum, ScopedEnumUsesClassTag, IsFixed);
// If this is an undefined enum, bail.
if (TUK != TUK_Definition && !Invalid)
return nullptr;
@@ -13992,7 +13984,7 @@
// in which case we want the caller to bail out.
if (CheckEnumRedeclaration(NameLoc.isValid() ? NameLoc : KWLoc,
ScopedEnum, EnumUnderlyingTy,
- EnumUnderlyingIsImplicit, PrevEnum))
+ IsFixed, PrevEnum))
return TUK == TUK_Declaration ? PrevTagDecl : nullptr;
}
@@ -14208,16 +14200,15 @@
// enum X { A, B, C } D; D should chain to X.
New = EnumDecl::Create(Context, SearchDC, KWLoc, Loc, Name,
cast_or_null<EnumDecl>(PrevDecl), ScopedEnum,
- ScopedEnumUsesClassTag, !EnumUnderlying.isNull());
+ ScopedEnumUsesClassTag, IsFixed);
if (isStdAlignValT && (!StdAlignValT || getStdAlignValT()->isImplicit()))
StdAlignValT = cast<EnumDecl>(New);
// If this is an undefined enum, warn.
if (TUK != TUK_Definition && !Invalid) {
TagDecl *Def;
- if (!EnumUnderlyingIsImplicit &&
- (getLangOpts().CPlusPlus11 || getLangOpts().ObjC2) &&
+ if (IsFixed && (getLangOpts().CPlusPlus11 || getLangOpts().ObjC2) &&
cast<EnumDecl>(New)->isFixed()) {
// C++0x: 7.2p2: opaque-enum-declaration.
// Conflicts are diagnosed above. Do nothing.
@@ -14249,6 +14240,7 @@
else
ED->setIntegerType(QualType(EnumUnderlying.get<const Type*>(), 0));
ED->setPromotionType(ED->getIntegerType());
+ assert(ED->isComplete() && "enum with type should be complete");
}
} else {
// struct/union/class
@@ -15707,7 +15699,7 @@
&EnumVal).get())) {
// C99 6.7.2.2p2: Make sure we have an integer constant expression.
} else {
- if (Enum->isFixed()) {
+ if (Enum->isComplete()) {
EltTy = Enum->getIntegerType();
// In Obj-C and Microsoft mode, require the enumeration value to be
@@ -16218,7 +16210,9 @@
if (LangOpts.ShortEnums)
Packed = true;
- if (Enum->isFixed()) {
+ // If the enum already has a type because it is fixed or dictated by the
+ // target, promote that type instead of analyzing the enumerators.
+ if (Enum->isComplete()) {
BestType = Enum->getIntegerType();
if (BestType->isPromotableIntegerType())
BestPromotionType = Context.getPromotedIntegerType(BestType);
Index: clang/lib/AST/Type.cpp
===================================================================
--- clang/lib/AST/Type.cpp
+++ clang/lib/AST/Type.cpp
@@ -1997,12 +1997,7 @@
EnumDecl *EnumD = cast<EnumType>(CanonicalType)->getDecl();
if (Def)
*Def = EnumD;
-
- // An enumeration with fixed underlying type is complete (C++0x 7.2p3).
- if (EnumD->isFixed())
- return false;
-
- return !EnumD->isCompleteDefinition();
+ return !EnumD->isComplete();
}
case Record: {
// A tagged type (struct/union/enum/class) is incomplete if the decl is a
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -2314,8 +2314,7 @@
Expr *val);
bool CheckEnumUnderlyingType(TypeSourceInfo *TI);
bool CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
- QualType EnumUnderlyingTy,
- bool EnumUnderlyingIsImplicit,
+ QualType EnumUnderlyingTy, bool IsFixed,
const EnumDecl *Prev);
/// Determine whether the body of an anonymous enumeration should be skipped.
Index: clang/include/clang/AST/Decl.h
===================================================================
--- clang/include/clang/AST/Decl.h
+++ clang/include/clang/AST/Decl.h
@@ -3449,7 +3449,9 @@
/// \brief Returns true if this can be considered a complete type.
bool isComplete() const {
- return isCompleteDefinition() || isFixed();
+ // IntegerType is set for fixed type enums and non-fixed but implicitly
+ // int-sized Microsoft enums.
+ return isCompleteDefinition() || IntegerType;
}
/// Returns true if this enum is either annotated with
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