PR40642: Fix determination of whether the final statement of a statement
expression is a discarded-value expression.
Summary:
We used to get this wrong in three ways:
1) During parsing, an expression-statement followed by the }) ending a
statement expression was always treated as producing the value of the
statement expression. That's wrong for ({ if (1) expr; })
2) During template instantiation, various kinds of statement (most
statements not appearing directly in a compound-statement) were not
treated as discarded-value expressions, resulting in missing volatile
loads (etc).
3) In all contexts, an expression-statement with attributes was not
treated as producing the value of the statement expression, eg
({ [[attr]] expr; }).
Also fix incorrect enforcement of OpenMP rule that directives can "only
be placed in the program at a position where ignoring or deleting the
directive would result in a program with correct syntax". In particular,
a label (be it goto, case, or default) should not affect whether
directives are permitted.
Reviewers: aaron.ballman, rjmccall
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D57984
llvm-svn: 354090
diff --git a/clang/lib/AST/Stmt.cpp b/clang/lib/AST/Stmt.cpp
index d1a4dc0..f2bb289 100644
--- a/clang/lib/AST/Stmt.cpp
+++ b/clang/lib/AST/Stmt.cpp
@@ -320,6 +320,23 @@
return New;
}
+const Expr *ValueStmt::getExprStmt() const {
+ const Stmt *S = this;
+ do {
+ if (const auto *E = dyn_cast<Expr>(S))
+ return E;
+
+ if (const auto *LS = dyn_cast<LabelStmt>(S))
+ S = LS->getSubStmt();
+ else if (const auto *AS = dyn_cast<AttributedStmt>(S))
+ S = AS->getSubStmt();
+ else
+ llvm_unreachable("unknown kind of ValueStmt");
+ } while (isa<ValueStmt>(S));
+
+ return nullptr;
+}
+
const char *LabelStmt::getName() const {
return getDecl()->getIdentifier()->getNameStart();
}