Author: rnk
Date: Mon Feb 12 09:37:06 2018
New Revision: 324913
URL: http://llvm.org/viewvc/llvm-project?rev=324913&view=rev
Log:
[Sema] Don't mark plain MS enums as fixed
Summary:
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.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D43110
Modified:
cfe/trunk/include/clang/AST/Decl.h
cfe/trunk/include/clang/Sema/Sema.h
cfe/trunk/lib/AST/Type.cpp
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
cfe/trunk/test/Sema/sign-compare-enum.c
Modified: cfe/trunk/include/clang/AST/Decl.h
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Decl.h?rev=324913&r1=324912&r2=324913&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Decl.h (original)
+++ cfe/trunk/include/clang/AST/Decl.h Mon Feb 12 09:37:06 2018
@@ -3449,7 +3449,9 @@ public:
/// \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
Modified: cfe/trunk/include/clang/Sema/Sema.h
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=324913&r1=324912&r2=324913&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Mon Feb 12 09:37:06 2018
@@ -2315,8 +2315,7 @@ public:
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.
Modified: cfe/trunk/lib/AST/Type.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Type.cpp?rev=324913&r1=324912&r2=324913&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Type.cpp (original)
+++ cfe/trunk/lib/AST/Type.cpp Mon Feb 12 09:37:06 2018
@@ -1997,12 +1997,7 @@ bool Type::isIncompleteType(NamedDecl **
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
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=324913&r1=324912&r2=324913&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Mon Feb 12 09:37:06 2018
@@ -13236,11 +13236,9 @@ bool Sema::CheckEnumUnderlyingType(TypeS
/// 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 @@ bool Sema::CheckEnumRedeclaration(
<< 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 @@ Decl *Sema::ActOnTag(Scope *S, unsigned
// 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;
@@ -13582,11 +13576,12 @@ Decl *Sema::ActOnTag(Scope *S, unsigned
EnumUnderlying = Context.IntTy.getTypePtr();
} else if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
- if (getLangOpts().MSVCCompat || TUK == TUK_Definition) {
- // Microsoft enums are always of int type.
+ // For MSVC ABI compatibility, unfixed enums must use an underlying type
+ // of 'int'. However, if this is an unfixed forward declaration, don't
set
+ // the underlying type unless the user enables -fms-compatibility. This
+ // makes unfixed forward declared enums incomplete and is more
conforming.
+ if (TUK == TUK_Definition || getLangOpts().MSVCCompat)
EnumUnderlying = Context.IntTy.getTypePtr();
- EnumUnderlyingIsImplicit = true;
- }
}
}
@@ -13612,8 +13607,7 @@ Decl *Sema::ActOnTag(Scope *S, unsigned
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 +13986,7 @@ Decl *Sema::ActOnTag(Scope *S, unsigned
// 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;
}
@@ -14208,7 +14202,7 @@ CreateNewDecl:
// 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);
@@ -14216,8 +14210,7 @@ CreateNewDecl:
// 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 +14242,7 @@ CreateNewDecl:
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 +15701,7 @@ EnumConstantDecl *Sema::CheckEnumConstan
&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 +16212,9 @@ void Sema::ActOnEnumBody(SourceLocation
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);
Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp?rev=324913&r1=324912&r2=324913&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp Mon Feb 12 09:37:06 2018
@@ -1041,8 +1041,7 @@ Decl *TemplateDeclInstantiator::VisitEnu
SemaRef.SubstType(TI->getType(), TemplateArgs,
UnderlyingLoc, DeclarationName());
SemaRef.CheckEnumRedeclaration(Def->getLocation(), Def->isScoped(),
- DefnUnderlying,
- /*EnumUnderlyingIsImplicit=*/false, Enum);
+ DefnUnderlying, /*IsFixed=*/true, Enum);
}
}
Modified: cfe/trunk/test/Sema/sign-compare-enum.c
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/sign-compare-enum.c?rev=324913&r1=324912&r2=324913&view=diff
==============================================================================
--- cfe/trunk/test/Sema/sign-compare-enum.c (original)
+++ cfe/trunk/test/Sema/sign-compare-enum.c Mon Feb 12 09:37:06 2018
@@ -1,24 +1,77 @@
-// RUN: %clang_cc1 -triple=x86_64-pc-linux-gnu -fsyntax-only -DUNSIGNED
-verify -Wsign-compare %s
-// RUN: %clang_cc1 -triple=x86_64-pc-win32 -fsyntax-only -DSIGNED -verify
-Wsign-compare %s
-// RUN: %clang_cc1 -triple=x86_64-pc-linux-gnu -fsyntax-only -DUNSIGNED
-DSILENCE -verify %s
-// RUN: %clang_cc1 -triple=x86_64-pc-win32 -fsyntax-only -DSIGNED -DSILENCE
-verify %s
-
-int main() {
- enum A { A_a = 0, A_b = 1 };
- static const int message[] = {0, 1};
- enum A a;
+// RUN: %clang_cc1 -triple=x86_64-pc-linux-gnu -fsyntax-only -verify
-Wsign-compare %s
+// RUN: %clang_cc1 -triple=x86_64-pc-win32 -fsyntax-only -verify
-Wsign-compare %s
+// RUN: %clang_cc1 -x c++ -triple=x86_64-pc-linux-gnu -fsyntax-only -verify
-Wsign-compare %s
+// RUN: %clang_cc1 -x c++ -triple=x86_64-pc-win32 -fsyntax-only -verify
-Wsign-compare %s
+// Check that -Wsign-compare is off by default.
+// RUN: %clang_cc1 -triple=x86_64-pc-linux-gnu -fsyntax-only -verify -DSILENCE
%s
+
+#ifdef SILENCE
+// expected-no-diagnostics
+#endif
+
+enum PosEnum {
+ A_a = 0,
+ A_b = 1,
+ A_c = 10
+};
+
+static const int message[] = {0, 1};
+
+int test_pos(enum PosEnum a) {
if (a < 2)
return 0;
-#if defined(SIGNED) && !defined(SILENCE)
- if (a < sizeof(message)/sizeof(message[0])) // expected-warning {{comparison
of integers of different signs: 'enum A' and 'unsigned long long'}}
- return 0;
-#else
- // expected-no-diagnostics
+ // No warning, except in Windows C mode, where PosEnum is 'int' and it can
+ // take on any value according to the C standard.
+#if !defined(SILENCE) && defined(_WIN32) && !defined(__cplusplus)
+ // expected-warning@+2 {{comparison of integers of different signs}}
+#endif
if (a < 2U)
return 0;
+
+ unsigned uv = 2;
+#if !defined(SILENCE) && defined(_WIN32) && !defined(__cplusplus)
+ // expected-warning@+2 {{comparison of integers of different signs}}
+#endif
+ if (a < uv)
+ return 1;
+
+#if !defined(SILENCE) && defined(_WIN32) && !defined(__cplusplus)
+ // expected-warning@+2 {{comparison of integers of different signs}}
+#endif
if (a < sizeof(message)/sizeof(message[0]))
return 0;
+ return 4;
+}
+
+enum NegEnum {
+ NE_a = -1,
+ NE_b = 0,
+ NE_c = 10
+};
+
+int test_neg(enum NegEnum a) {
+ if (a < 2)
+ return 0;
+
+#ifndef SILENCE
+ // expected-warning@+2 {{comparison of integers of different signs}}
+#endif
+ if (a < 2U)
+ return 0;
+
+ unsigned uv = 2;
+#ifndef SILENCE
+ // expected-warning@+2 {{comparison of integers of different signs}}
+#endif
+ if (a < uv)
+ return 1;
+
+#ifndef SILENCE
+ // expected-warning@+2 {{comparison of integers of different signs}}
#endif
+ if (a < sizeof(message)/sizeof(message[0]))
+ return 0;
+ return 4;
}
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