From 8c595da41962a93868650c80209f21808222ff53 Mon Sep 17 00:00:00 2001
From: "podivilov@chromium.org"
 <podivilov@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Tue, 7 Sep 2010 15:34:16 +0000
Subject: [PATCH] Move stack check below while statement.

Call to Runtime_StackGuard should be generated after loop body.
Otherwise, break position will be the previous position before
loop statement.

Review URL: http://codereview.chromium.org/3302012

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5423 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/full-codegen.cc       | 15 +++++++++------
 test/cctest/test-debug.cc | 15 +++++++++++++++
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/src/full-codegen.cc b/src/full-codegen.cc
index 59cbad9..5ffebfb 100644
--- a/src/full-codegen.cc
+++ b/src/full-codegen.cc
@@ -825,7 +825,7 @@ void FullCodeGenerator::VisitDoWhileStatement(DoWhileStatement* stmt) {
 
 void FullCodeGenerator::VisitWhileStatement(WhileStatement* stmt) {
   Comment cmnt(masm_, "[ WhileStatement");
-  Label body, stack_limit_hit, stack_check_success;
+  Label body, stack_limit_hit, stack_check_success, done;
 
   Iteration loop_statement(this, stmt);
   increment_loop_depth();
@@ -833,11 +833,6 @@ void FullCodeGenerator::VisitWhileStatement(WhileStatement* stmt) {
   // Emit the test at the bottom of the loop.
   __ jmp(loop_statement.continue_target());
 
-  __ bind(&stack_limit_hit);
-  StackCheckStub stack_stub;
-  __ CallStub(&stack_stub);
-  __ jmp(&stack_check_success);
-
   __ bind(&body);
   Visit(stmt->body());
   __ bind(loop_statement.continue_target());
@@ -856,6 +851,14 @@ void FullCodeGenerator::VisitWhileStatement(WhileStatement* stmt) {
                   loop_statement.break_target());
 
   __ bind(loop_statement.break_target());
+  __ jmp(&done);
+
+  __ bind(&stack_limit_hit);
+  StackCheckStub stack_stub;
+  __ CallStub(&stack_stub);
+  __ jmp(&stack_check_success);
+
+  __ bind(&done);
   decrement_loop_depth();
 }
 
diff --git a/test/cctest/test-debug.cc b/test/cctest/test-debug.cc
index 9531b57..f5526ce 100644
--- a/test/cctest/test-debug.cc
+++ b/test/cctest/test-debug.cc
@@ -4591,6 +4591,18 @@ int GetTotalFramesInt(char *message) {
 }
 
 
+// We match parts of the message to get source line.
+int GetSourceLineFromBreakEventMessage(char *message) {
+  const char* source_line = "\"sourceLine\":";
+  char* pos = strstr(message, source_line);
+  if (pos == NULL) {
+    return -1;
+  }
+  int res = -1;
+  res = StringToInt(pos + strlen(source_line));
+  return res;
+}
+
 /* Test MessageQueues */
 /* Tests the message queues that hold debugger commands and
  * response messages to the debugger.  Fills queues and makes
@@ -4870,6 +4882,9 @@ static void ThreadedMessageHandler(const v8::Debug::Message& message) {
   v8::String::Value json(message.GetJSON());
   Utf16ToAscii(*json, json.length(), print_buffer);
   if (IsBreakEventMessage(print_buffer)) {
+    // Check that we are inside the while loop.
+    int source_line = GetSourceLineFromBreakEventMessage(print_buffer);
+    CHECK(8 <= source_line && source_line <= 13);
     threaded_debugging_barriers.barrier_2.Wait();
   }
 }
-- 
2.7.4