[CodeGen] Emit lifetime.end intrinsic after objects are destructed in

landing pads.

Previously, lifetime.end intrinsics were inserted only on normal control
flows. This prevented StackColoring from merging stack slots for objects
that were destroyed on the exception handling control flow since it
couldn't tell their lifetime ranges were disjoint. This patch fixes
code-gen to emit the intrinsic on both control flows.

rdar://problem/22181976

Differential Revision: http://reviews.llvm.org/D18196

llvm-svn: 265197

1 files changed, 14 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGCleanup.cpp b/clang/lib/CodeGen/CGCleanup.cpp
index 2678b33f392..95333d0ddac 100644
--- a/clang/lib/CodeGen/CGCleanup.cpp
+++ b/clang/lib/CodeGen/CGCleanup.cpp
@@ -157,6 +157,20 @@ bool EHScopeStack::containsOnlyLifetimeMarkers(
   return true;
 }
 
+bool EHScopeStack::requiresLandingPad() const {
+  for (stable_iterator si = getInnermostEHScope(); si != stable_end(); ) {
+    // Skip lifetime markers.
+    if (auto *cleanup = dyn_cast<EHCleanupScope>(&*find(si)))
+      if (cleanup->isLifetimeMarker()) {
+        si = cleanup->getEnclosingEHScope();
+        continue;
+      }
+    return true;
+  }
+
+  return false;
+}
+
 EHScopeStack::stable_iterator
 EHScopeStack::getInnermostActiveNormalCleanup() const {
   for (stable_iterator si = getInnermostNormalCleanup(), se = stable_end();