Commit 8a2eba80 authored Aug 17, 2018 by Reid Kleckner

Merging r340101:

------------------------------------------------------------------------
r340101 | rnk | 2018-08-17 15:11:31 -0700 (Fri, 17 Aug 2018) | 14 lines

Don't warn on returning the address of a label from a statement expression

Summary:
There isn't anything inherently wrong with returning a label from a
statement expression. In practice, the Linux kernel uses this pattern to
materialize PCs.

Fixes PR38569

Reviewers: niravd, rsmith, nickdesaulniers

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D50805
------------------------------------------------------------------------

llvm-svn: 340103

parent 786ae53d

clang/lib/Sema/SemaInit.cpp

+4 −0

Original line number	Diff line number	Diff line
		@@ -6942,6 +6942,10 @@ void Sema::checkInitializerLifetime(const InitializedEntity &Entity,
		} else if (isa<BlockExpr>(L)) {
		Diag(DiagLoc, diag::err_ret_local_block) << DiagRange;
		} else if (isa<AddrLabelExpr>(L)) {
		// Don't warn when returning a label from a statement expression.
		// Leaving the scope doesn't end its lifetime.
		if (LK == LK_StmtExprResult)
		return false;
		Diag(DiagLoc, diag::warn_ret_addr_label) << DiagRange;
		} else {
		Diag(DiagLoc, diag::warn_ret_local_temp_addr_ref)

clang/test/Sema/statements.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -34,6 +34,15 @@ bar:
		return &&bar; // expected-warning {{returning address of label, which is local}}
		}

		// PR38569: Don't warn when returning a label from a statement expression.
		void test10_logpc(void*);
		void test10a() {
		test10_logpc(({
		my_pc:
		&&my_pc;
		}));
		}

		// PR6034
		void test11(int bit) {
		switch (bit)