Add support for attribute enum_extensibility.
This commit adds support for a new attribute that will be used to
distinguish between extensible and inextensible enums. There are three
main purposes of this attribute:
1. Give better control over when enum-related warnings are issued.
For example, in the code below, clang will not issue a -Wassign-enum
warning if the enum is marked "open":
enum __attribute__((enum_extensibility(closed))) EnumClosed {
B0 = 1, B1 = 10
};
enum __attribute__((enum_extensibility(open))) EnumOpen {
C0 = 1, C1 = 10
};
enum EnumClosed ec = 100; // warning issued
enum EnumOpen eo = 100; // no warning
2. Enable code-completion and debugging tools to offer better
suggestions.
3. Make it easier for swift's clang importer to determine which swift
type an enum should be mapped to.
For more details, see the discussion I started on cfe-dev:
http://lists.llvm.org/pipermail/cfe-dev/2017-February/052748.html
rdar://problem/12764379
rdar://problem/23145650
Differential Revision: https://reviews.llvm.org/D30766
llvm-svn: 298332
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index d7d7122..bc5f605 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -15358,7 +15358,7 @@
bool Sema::IsValueInFlagEnum(const EnumDecl *ED, const llvm::APInt &Val,
bool AllowMask) const {
- assert(ED->hasAttr<FlagEnumAttr>() && "looking for value in non-flag enum");
+ assert(ED->isClosedFlag() && "looking for value in non-flag or open enum");
assert(ED->isCompleteDefinition() && "expected enum definition");
auto R = FlagBitsCache.insert(std::make_pair(ED, llvm::APInt()));
@@ -15603,7 +15603,7 @@
CheckForDuplicateEnumValues(*this, Elements, Enum, EnumType);
- if (Enum->hasAttr<FlagEnumAttr>()) {
+ if (Enum->isClosedFlag()) {
for (Decl *D : Elements) {
EnumConstantDecl *ECD = cast_or_null<EnumConstantDecl>(D);
if (!ECD) continue; // Already issued a diagnostic.
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 3979383..1c350a7 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -2943,6 +2943,28 @@
Attr.getAttributeSpellingListIndex()));
}
+static void handleEnumExtensibilityAttr(Sema &S, Decl *D,
+ const AttributeList &Attr) {
+ if (!Attr.isArgIdent(0)) {
+ S.Diag(Attr.getLoc(), diag::err_attribute_argument_n_type)
+ << Attr.getName() << 0 << AANT_ArgumentIdentifier;
+ return;
+ }
+
+ EnumExtensibilityAttr::Kind ExtensibilityKind;
+ IdentifierInfo *II = Attr.getArgAsIdent(0)->Ident;
+ if (!EnumExtensibilityAttr::ConvertStrToKind(II->getName(),
+ ExtensibilityKind)) {
+ S.Diag(Attr.getLoc(), diag::warn_attribute_type_not_supported)
+ << Attr.getName() << II;
+ return;
+ }
+
+ D->addAttr(::new (S.Context) EnumExtensibilityAttr(
+ Attr.getRange(), S.Context, ExtensibilityKind,
+ Attr.getAttributeSpellingListIndex()));
+}
+
/// Handle __attribute__((format_arg((idx)))) attribute based on
/// http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
static void handleFormatArgAttr(Sema &S, Decl *D, const AttributeList &Attr) {
@@ -5856,6 +5878,9 @@
case AttributeList::AT_FlagEnum:
handleSimpleAttribute<FlagEnumAttr>(S, D, Attr);
break;
+ case AttributeList::AT_EnumExtensibility:
+ handleEnumExtensibilityAttr(S, D, Attr);
+ break;
case AttributeList::AT_Flatten:
handleSimpleAttribute<FlattenAttr>(S, D, Attr);
break;
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 3f6c467..f393e3e 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -711,6 +711,9 @@
EnumValsTy::iterator &EI,
EnumValsTy::iterator &EIEnd,
const llvm::APSInt &Val) {
+ if (!ED->isClosed())
+ return false;
+
if (const DeclRefExpr *DRE =
dyn_cast<DeclRefExpr>(CaseExpr->IgnoreParenImpCasts())) {
if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
@@ -722,15 +725,14 @@
}
}
- if (ED->hasAttr<FlagEnumAttr>()) {
+ if (ED->hasAttr<FlagEnumAttr>())
return !S.IsValueInFlagEnum(ED, Val, false);
- } else {
- while (EI != EIEnd && EI->first < Val)
- EI++;
- if (EI != EIEnd && EI->first == Val)
- return false;
- }
+ while (EI != EIEnd && EI->first < Val)
+ EI++;
+
+ if (EI != EIEnd && EI->first == Val)
+ return false;
return true;
}
@@ -1147,7 +1149,7 @@
}
}
- if (TheDefaultStmt && UnhandledNames.empty())
+ if (TheDefaultStmt && UnhandledNames.empty() && ED->isClosedNonFlag())
Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);
// Produce a nice diagnostic if multiple values aren't handled.
@@ -1198,6 +1200,9 @@
AdjustAPSInt(RhsVal, DstWidth, DstIsSigned);
const EnumDecl *ED = ET->getDecl();
+ if (!ED->isClosed())
+ return;
+
if (ED->hasAttr<FlagEnumAttr>()) {
if (!IsValueInFlagEnum(ED, RhsVal, true))
Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)