Add support for namespaces on #pragma clang attribute
Namespaces are introduced by adding an "identifier." before a
push/pop directive. Pop directives with namespaces can only pop a
attribute group that was pushed with the same namespace. Push and pop
directives that don't opt into namespaces have the same semantics.
This is necessary to prevent a pitfall of using multiple #pragma
clang attribute directives spread out in a large file, particularly
when macros are involved. It isn't easy to see which pop corripsonds
to which push, so its easy to inadvertently pop the wrong group.
Differential revision: https://reviews.llvm.org/D55628
llvm-svn: 349845
diff --git a/clang/lib/Parse/ParsePragma.cpp b/clang/lib/Parse/ParsePragma.cpp
index e476c9b..3204cf0 100644
--- a/clang/lib/Parse/ParsePragma.cpp
+++ b/clang/lib/Parse/ParsePragma.cpp
@@ -1139,6 +1139,7 @@
enum ActionType { Push, Pop, Attribute };
ParsedAttributes &Attributes;
ActionType Action;
+ const IdentifierInfo *Namespace = nullptr;
ArrayRef<Token> Tokens;
PragmaAttributeInfo(ParsedAttributes &Attributes) : Attributes(Attributes) {}
@@ -1393,7 +1394,7 @@
auto *Info = static_cast<PragmaAttributeInfo *>(Tok.getAnnotationValue());
if (Info->Action == PragmaAttributeInfo::Pop) {
ConsumeAnnotationToken();
- Actions.ActOnPragmaAttributePop(PragmaLoc);
+ Actions.ActOnPragmaAttributePop(PragmaLoc, Info->Namespace);
return;
}
// Parse the actual attribute with its arguments.
@@ -1403,7 +1404,7 @@
if (Info->Action == PragmaAttributeInfo::Push && Info->Tokens.empty()) {
ConsumeAnnotationToken();
- Actions.ActOnPragmaAttributeEmptyPush(PragmaLoc);
+ Actions.ActOnPragmaAttributeEmptyPush(PragmaLoc, Info->Namespace);
return;
}
@@ -1555,7 +1556,7 @@
// Handle a mixed push/attribute by desurging to a push, then an attribute.
if (Info->Action == PragmaAttributeInfo::Push)
- Actions.ActOnPragmaAttributeEmptyPush(PragmaLoc);
+ Actions.ActOnPragmaAttributeEmptyPush(PragmaLoc, Info->Namespace);
Actions.ActOnPragmaAttributeAttribute(Attribute, PragmaLoc,
std::move(SubjectMatchRules));
@@ -3118,12 +3119,22 @@
///
/// The syntax is:
/// \code
-/// #pragma clang attribute push(attribute, subject-set)
+/// #pragma clang attribute push (attribute, subject-set)
/// #pragma clang attribute push
/// #pragma clang attribute (attribute, subject-set)
/// #pragma clang attribute pop
/// \endcode
///
+/// There are also 'namespace' variants of push and pop directives. The bare
+/// '#pragma clang attribute (attribute, subject-set)' version doesn't require a
+/// namespace, since it always applies attributes to the most recently pushed
+/// group, regardless of namespace.
+/// \code
+/// #pragma clang attribute namespace.push (attribute, subject-set)
+/// #pragma clang attribute namespace.push
+/// #pragma clang attribute namespace.pop
+/// \endcode
+///
/// The subject-set clause defines the set of declarations which receive the
/// attribute. Its exact syntax is described in the LanguageExtensions document
/// in Clang's documentation.
@@ -3139,6 +3150,22 @@
auto *Info = new (PP.getPreprocessorAllocator())
PragmaAttributeInfo(AttributesForPragmaAttribute);
+ // Parse the optional namespace followed by a period.
+ if (Tok.is(tok::identifier)) {
+ IdentifierInfo *II = Tok.getIdentifierInfo();
+ if (!II->isStr("push") && !II->isStr("pop")) {
+ Info->Namespace = II;
+ PP.Lex(Tok);
+
+ if (!Tok.is(tok::period)) {
+ PP.Diag(Tok.getLocation(), diag::err_pragma_attribute_expected_period)
+ << II;
+ return;
+ }
+ PP.Lex(Tok);
+ }
+ }
+
if (!Tok.isOneOf(tok::identifier, tok::l_paren)) {
PP.Diag(Tok.getLocation(),
diag::err_pragma_attribute_expected_push_pop_paren);
@@ -3146,9 +3173,16 @@
}
// Determine what action this pragma clang attribute represents.
- if (Tok.is(tok::l_paren))
+ if (Tok.is(tok::l_paren)) {
+ if (Info->Namespace) {
+ PP.Diag(Tok.getLocation(),
+ diag::err_pragma_attribute_namespace_on_attribute);
+ PP.Diag(Tok.getLocation(),
+ diag::note_pragma_attribute_namespace_on_attribute);
+ return;
+ }
Info->Action = PragmaAttributeInfo::Attribute;
- else {
+ } else {
const IdentifierInfo *II = Tok.getIdentifierInfo();
if (II->isStr("push"))
Info->Action = PragmaAttributeInfo::Push;