Fix a stack-height mismatch during deoptimization.

When deoptimizing after a conditional expression in an effect context, we
should not see the value of the conditional expression.

BUG=v8:1237

Review URL: http://codereview.chromium.org/6625057

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7082 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen.cc

@@ -302,6 +302,13 @@ void HBasicBlock::Verify() {
   // Check that every block is finished.
   ASSERT(IsFinished());
   ASSERT(block_id() >= 0);
+
+  // Check that the incoming edges are in edge split form.
+  if (predecessors_.length() > 1) {
+    for (int i = 0; i < predecessors_.length(); ++i) {
+      ASSERT(predecessors_[i]->end()->SecondSuccessor() == NULL);
+    }
+  }
 }
 #endif
 
@@ -2827,18 +2834,22 @@ void HGraphBuilder::VisitConditional(Conditional* expr) {
   cond_true->SetJoinId(expr->ThenId());
   cond_false->SetJoinId(expr->ElseId());
 
-  // TOOD(kmillikin): Visit the subexpressions in the same AST context as
-  // the whole expression.
+  // Visit the true and false subexpressions in the same AST context as the
+  // whole expression.
   set_current_block(cond_true);
-  VISIT_FOR_VALUE(expr->then_expression());
+  Visit(expr->then_expression());
+  CHECK_BAILOUT;
   HBasicBlock* other = current_block();
 
   set_current_block(cond_false);
-  VISIT_FOR_VALUE(expr->else_expression());
+  Visit(expr->else_expression());
+  CHECK_BAILOUT;
 
-  HBasicBlock* join = CreateJoin(other, current_block(), expr->id());
-  set_current_block(join);
-  ast_context()->ReturnValue(Pop());
+  if (!ast_context()->IsTest()) {
+    HBasicBlock* join = CreateJoin(other, current_block(), expr->id());
+    set_current_block(join);
+    if (!ast_context()->IsEffect()) ast_context()->ReturnValue(Pop());
+  }
 }
 
 

test/mjsunit/regress/regress-1237.js

+// Copyright 2011 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Deoptimization after a conditional expression in an effect context should
+// not see the value of the expression.
+function observe(x, y) { return x; }
+function test(x) {
+  return observe(1, ((x? observe(observe.prototype.x): 'c'), x + 1));
+}
+
+for (var i = 0; i < 10000000; ++i) test(0);
+test("a");