Reapply r183721, reverted in r183776, with a fix for a bug in the former (we

were lacking ExprWithCleanups nodes in some cases where the new approach to
lifetime extension needed them).

Original commit message:

Rework IR emission for lifetime-extended temporaries. Instead of trying to walk
into the expression and dig out a single lifetime-extended entity and manually
pull its cleanup outside the expression, instead keep a list of the cleanups
which we'll need to emit when we get to the end of the full-expression. Also
emit those cleanups early, as EH-only cleanups, to cover the case that the
full-expression does not terminate normally. This allows IR generation to
properly model temporary lifetime when multiple temporaries are extended by the
same declaration.

We have a pre-existing bug where an exception thrown from a temporary's
destructor does not clean up lifetime-extended temporaries created in the same
expression and extended to automatic storage duration; that is not fixed by
this patch.

llvm-svn: 183859

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGCleanup.h b/clang/lib/CodeGen/CGCleanup.h
index 40a7502973e..61d9f02a08f 100644
--- a/clang/lib/CodeGen/CGCleanup.h
+++ b/clang/lib/CodeGen/CGCleanup.h
@@ -374,6 +374,11 @@ public:
     return new (Buffer) T(N, a0, a1, a2);
   }
 
+  void pushCopyOfCleanup(CleanupKind Kind, const void *Cleanup, size_t Size) {
+    void *Buffer = pushCleanup(Kind, Size);
+    std::memcpy(Buffer, Cleanup, Size);
+  }
+
   /// Pops a cleanup scope off the stack.  This is private to CGCleanup.cpp.
   void popCleanup();