[llvm-branch-commits] [cfe-branch] r340103 - Merging r340101:

[Reid Kleckner via llvm-branch-commits]

Author: rnk
Date: Fri Aug 17 15:18:56 2018
New Revision: 340103

URL: http://llvm.org/viewvc/llvm-project?rev=340103&view=rev
Log:
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
------------------------------------------------------------------------

Modified:
    cfe/branches/release_70/   (props changed)
    cfe/branches/release_70/lib/Sema/SemaInit.cpp
    cfe/branches/release_70/test/Sema/statements.c

Propchange: cfe/branches/release_70/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Fri Aug 17 15:18:56 2018
@@ -1,4 +1,4 @@
 /cfe/branches/type-system-rewrite:134693-134817
-/cfe/trunk:338552-338553,338602,338627,338749,338934,338942,339074,339128,339170,339210,339264,339281,339317,339428,339494,339597,339603,340079
+/cfe/trunk:338552-338553,338602,338627,338749,338934,338942,339074,339128,339170,339210,339264,339281,339317,339428,339494,339597,339603,340079,340101
 /cfe/trunk/test:170344
 /cfe/trunk/test/SemaTemplate:126920

Modified: cfe/branches/release_70/lib/Sema/SemaInit.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/branches/release_70/lib/Sema/SemaInit.cpp?rev=340103&r1=340102&r2=340103&view=diff
==============================================================================
--- cfe/branches/release_70/lib/Sema/SemaInit.cpp (original)
+++ cfe/branches/release_70/lib/Sema/SemaInit.cpp Fri Aug 17 15:18:56 2018
@@ -6942,6 +6942,10 @@ void Sema::checkInitializerLifetime(cons
       } 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)

Modified: cfe/branches/release_70/test/Sema/statements.c
URL: http://llvm.org/viewvc/llvm-project/cfe/branches/release_70/test/Sema/statements.c?rev=340103&r1=340102&r2=340103&view=diff
==============================================================================
--- cfe/branches/release_70/test/Sema/statements.c (original)
+++ cfe/branches/release_70/test/Sema/statements.c Fri Aug 17 15:18:56 2018
@@ -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)