r242970 - [MS Compat] Allow _Atomic(Type) and 'struct _Atomic' to coexist
David Majnemer
david.majnemer at gmail.com
Wed Jul 22 16:46:19 PDT 2015
Author: majnemer
Date: Wed Jul 22 18:46:18 2015
New Revision: 242970
URL: http://llvm.org/viewvc/llvm-project?rev=242970&view=rev
Log:
[MS Compat] Allow _Atomic(Type) and 'struct _Atomic' to coexist
MSVC 2013 ships, as part of its STL implementation, a class named
'_Atomic'. This is unfortunate because this keyword is in conflict with
the C11 keyword with the same name. Our solution was to disable this
keyword when targeting MSVC 2013 and reenable it for 2015.
However, this makes it impossible for clang's headers to make use of
_Atomic. This is problematic in the case of libc++ as it makes heavy
use of this keyword.
Let the keywordness of _Atomic float under certain circumstances:
the body of a class named _Atomic, or a class with a base specifier
named _Atomic, will not have the keyword variant of _Atomic for the
duration of the class body. This is sufficient to allow us to correctly
handle _Atomic in the STL while permitting us to use _Atomic as a
keyword everywhere else.
Differential Revision: http://reviews.llvm.org/D11233
Modified:
cfe/trunk/include/clang/Basic/IdentifierTable.h
cfe/trunk/include/clang/Basic/TokenKinds.def
cfe/trunk/lib/Parse/ParseDecl.cpp
cfe/trunk/lib/Parse/ParseDeclCXX.cpp
cfe/trunk/test/SemaCXX/MicrosoftCompatibility.cpp
Modified: cfe/trunk/include/clang/Basic/IdentifierTable.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/IdentifierTable.h?rev=242970&r1=242969&r2=242970&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/IdentifierTable.h (original)
+++ cfe/trunk/include/clang/Basic/IdentifierTable.h Wed Jul 22 18:46:18 2015
@@ -62,7 +62,7 @@ class IdentifierInfo {
// partially) from an AST file.
bool ChangedAfterLoad : 1; // True if identifier has changed from the
// definition loaded from an AST file.
- bool RevertedTokenID : 1; // True if RevertTokenIDToIdentifier was
+ bool RevertedTokenID : 1; // True if revertTokenIDToIdentifier was
// called.
bool OutOfDate : 1; // True if there may be additional
// information about this identifier
@@ -152,7 +152,7 @@ public:
/// tokens.
tok::TokenKind getTokenID() const { return (tok::TokenKind)TokenID; }
- /// \brief True if RevertTokenIDToIdentifier() was called.
+ /// \brief True if revertTokenIDToIdentifier() was called.
bool hasRevertedTokenIDToIdentifier() const { return RevertedTokenID; }
/// \brief Revert TokenID to tok::identifier; used for GNU libstdc++ 4.2
@@ -166,6 +166,11 @@ public:
TokenID = tok::identifier;
RevertedTokenID = true;
}
+ void revertIdentifierToTokenID(tok::TokenKind TK) {
+ assert(TokenID == tok::identifier && "Should be at tok::identifier");
+ TokenID = TK;
+ RevertedTokenID = false;
+ }
/// \brief Return the preprocessor keyword ID for this identifier.
///
Modified: cfe/trunk/include/clang/Basic/TokenKinds.def
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/TokenKinds.def?rev=242970&r1=242969&r2=242970&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/TokenKinds.def (original)
+++ cfe/trunk/include/clang/Basic/TokenKinds.def Wed Jul 22 18:46:18 2015
@@ -280,7 +280,7 @@ KEYWORD(volatile , KE
KEYWORD(while , KEYALL)
KEYWORD(_Alignas , KEYALL)
KEYWORD(_Alignof , KEYALL)
-KEYWORD(_Atomic , KEYALL|KEYNOMS18|KEYNOOPENCL)
+KEYWORD(_Atomic , KEYALL|KEYNOOPENCL)
KEYWORD(_Bool , KEYNOCXX)
KEYWORD(_Complex , KEYALL)
KEYWORD(_Generic , KEYALL)
Modified: cfe/trunk/lib/Parse/ParseDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseDecl.cpp?rev=242970&r1=242969&r2=242970&view=diff
==============================================================================
--- cfe/trunk/lib/Parse/ParseDecl.cpp (original)
+++ cfe/trunk/lib/Parse/ParseDecl.cpp Wed Jul 22 18:46:18 2015
@@ -2647,6 +2647,18 @@ void Parser::ParseDeclarationSpecifiers(
const char *PrevSpec = nullptr;
unsigned DiagID = 0;
+ // HACK: MSVC doesn't consider _Atomic to be a keyword and its STL
+ // implementation for VS2013 uses _Atomic as an identifier for one of the
+ // classes in <atomic>.
+ //
+ // A typedef declaration containing _Atomic<...> is among the places where
+ // the class is used. If we are currently parsing such a declaration, treat
+ // the token as an identifier.
+ if (getLangOpts().MSVCCompat && Tok.is(tok::kw__Atomic) &&
+ DS.getStorageClassSpec() == clang::DeclSpec::SCS_typedef &&
+ !DS.hasTypeSpecifier() && GetLookAheadToken(1).is(tok::less))
+ Tok.setKind(tok::identifier);
+
SourceLocation Loc = Tok.getLocation();
switch (Tok.getKind()) {
Modified: cfe/trunk/lib/Parse/ParseDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseDeclCXX.cpp?rev=242970&r1=242969&r2=242970&view=diff
==============================================================================
--- cfe/trunk/lib/Parse/ParseDeclCXX.cpp (original)
+++ cfe/trunk/lib/Parse/ParseDeclCXX.cpp Wed Jul 22 18:46:18 2015
@@ -1308,6 +1308,35 @@ void Parser::ParseClassSpecifier(tok::To
// allow libstdc++ 4.2 and libc++ to work properly.
TryKeywordIdentFallback(true);
+ struct PreserveAtomicIdentifierInfoRAII {
+ PreserveAtomicIdentifierInfoRAII(Token &Tok, bool Enabled)
+ : AtomicII(nullptr) {
+ if (!Enabled)
+ return;
+ assert(Tok.is(tok::kw__Atomic));
+ AtomicII = Tok.getIdentifierInfo();
+ AtomicII->revertTokenIDToIdentifier();
+ Tok.setKind(tok::identifier);
+ }
+ ~PreserveAtomicIdentifierInfoRAII() {
+ if (!AtomicII)
+ return;
+ AtomicII->revertIdentifierToTokenID(tok::kw__Atomic);
+ }
+ IdentifierInfo *AtomicII;
+ };
+
+ // HACK: MSVC doesn't consider _Atomic to be a keyword and its STL
+ // implementation for VS2013 uses _Atomic as an identifier for one of the
+ // classes in <atomic>. When we are parsing 'struct _Atomic', don't consider
+ // '_Atomic' to be a keyword. We are careful to undo this so that clang can
+ // use '_Atomic' in its own header files.
+ bool ShouldChangeAtomicToIdentifier = getLangOpts().MSVCCompat &&
+ Tok.is(tok::kw__Atomic) &&
+ TagType == DeclSpec::TST_struct;
+ PreserveAtomicIdentifierInfoRAII AtomicTokenGuard(
+ Tok, ShouldChangeAtomicToIdentifier);
+
// Parse the (optional) nested-name-specifier.
CXXScopeSpec &SS = DS.getTypeSpecScope();
if (getLangOpts().CPlusPlus) {
@@ -1859,6 +1888,15 @@ BaseResult Parser::ParseBaseSpecifier(De
CheckMisplacedCXX11Attribute(Attributes, StartLoc);
// Parse the class-name.
+
+ // HACK: MSVC doesn't consider _Atomic to be a keyword and its STL
+ // implementation for VS2013 uses _Atomic as an identifier for one of the
+ // classes in <atomic>. Treat '_Atomic' to be an identifier when we are
+ // parsing the class-name for a base specifier.
+ if (getLangOpts().MSVCCompat && Tok.is(tok::kw__Atomic) &&
+ NextToken().is(tok::less))
+ Tok.setKind(tok::identifier);
+
SourceLocation EndLocation;
SourceLocation BaseLoc;
TypeResult BaseType = ParseBaseTypeSpecifier(BaseLoc, EndLocation);
Modified: cfe/trunk/test/SemaCXX/MicrosoftCompatibility.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/MicrosoftCompatibility.cpp?rev=242970&r1=242969&r2=242970&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/MicrosoftCompatibility.cpp (original)
+++ cfe/trunk/test/SemaCXX/MicrosoftCompatibility.cpp Wed Jul 22 18:46:18 2015
@@ -9,11 +9,18 @@ typedef unsigned short char16_t;
typedef unsigned int char32_t;
#endif
-#if _MSC_VER >= 1900
_Atomic(int) z;
-#else
-struct _Atomic {};
-#endif
+template <typename T>
+struct _Atomic {
+ _Atomic() {}
+ ~_Atomic() {}
+};
+template <typename T>
+struct atomic : _Atomic<T> {
+ typedef _Atomic<T> TheBase;
+ TheBase field;
+};
+_Atomic(int) alpha;
typename decltype(3) a; // expected-warning {{expected a qualified name after 'typename'}}
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