[PATCH] D13973: CFG: Delay creating Dtors for CompoundStmts which end in ReturnStmt

[Matthias Gehre via cfe-commits]

mgehre created this revision.
mgehre added a reviewer: krememek.
mgehre added a subscriber: cfe-commits.

VisitReturnStmt would create a new block with including Dtors, so the Dtors created
in VisitCompoundStmts would be in an unreachable block.

Example:

struct S {
  ~S();
}

void f()
{
  S s;
  return;
}

void g()
{
  S s;
}

Before this patch, f has one additional unreachable block containing just the
destructor of S. With this patch, both f and g have the same blocks.

http://reviews.llvm.org/D13973

Files:
  lib/Analysis/CFG.cpp

Index: lib/Analysis/CFG.cpp
===================================================================
--- lib/Analysis/CFG.cpp
+++ lib/Analysis/CFG.cpp
@@ -1942,7 +1942,15 @@
 
 
 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
-  addLocalScopeAndDtors(C);
+  LocalScope::const_iterator scopeBeginPos = ScopePos;
+  if (BuildOpts.AddImplicitDtors) {
+    addLocalScopeForStmt(C);
+  }
+  if(!C->body_empty() && !dyn_cast<ReturnStmt>(*C->body_rbegin())) {
+    //If the body ends with a ReturnStmt, the Dtors will be added in VisitReturnStmt
+    addAutomaticObjDtors(ScopePos, scopeBeginPos, C);
+  }
+
   CFGBlock *LastBlock = Block;
 
   for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend();


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