Fix crash in CFGBuilder involving implicit destructor calls and gotos jumping after an object was declared. Fixes PR 10620.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@137426 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 31 insertions, 6 deletions

diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index 1edb328d01..ea126a9689 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -191,8 +191,8 @@ int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
   int D = 0;
   const_iterator F = *this;
   while (F.Scope != L.Scope) {
-    assert (F != const_iterator()
-        && "L iterator is not reachable from F iterator.");
+    if (F == const_iterator())
+      return D;
     D += F.VarIter;
     F = F.Scope->Prev;
   }
@@ -816,10 +816,12 @@ void CFGBuilder::addLocalScopeAndDtors(Stmt* S) {
 /// performed in place specified with iterator.
 void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I,
     LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) {
-  BumpVectorContext& C = cfg->getBumpVectorContext();
-  I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C);
-  while (B != E)
-    I = Blk->insertAutomaticObjDtor(I, *B++, S);
+  if (int Cnt = B.distance(E)) {
+    BumpVectorContext& C = cfg->getBumpVectorContext();
+    I = Blk->beginAutomaticObjDtorsInsert(I, Cnt, C);
+    while (B != E)
+      I = Blk->insertAutomaticObjDtor(I, *B++, S);
+  }
 }
 
 /// appendAutomaticObjDtors - Append destructor CFGElements for variables with
diff --git a/test/SemaCXX/cfg.cpp b/test/SemaCXX/cfg.cpp
new file mode 100644
index 0000000000..93cf90ba45
--- /dev/null
+++ b/test/SemaCXX/cfg.cpp
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -fsyntax-only -Wuninitialized -fsyntax-only %s
+
+// Test that the CFG builder handles destructors and gotos jumping between
+// scope boundaries.  Previously this crashed (PR 10620).
+struct S_10620 {
+  S_10620(const S_10620 &x);
+  ~S_10620();
+};
+void PR10620(int x, const S_10620& s) {
+  if (x) {
+    goto done;
+  }
+  const S_10620 s2(s);
+done:
+  ;
+}
+void PR10620_2(int x, const S_10620& s) {
+  if (x)
+    goto done;
+  const S_10620 s2(s);
+done:
+  ;
+}
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