Add support for debug break in Dart source.

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
===================================================================
--- runtime/vm/parser.cc	(revision 45190)
+++ runtime/vm/parser.cc	(working copy)
@@ -38,6 +38,7 @@
 namespace dart {
 
 DEFINE_FLAG(bool, enable_asserts, false, "Enable assert statements.");
+DEFINE_FLAG(bool, enable_debug_break, false, "Allow use of break \"message\".");
 DEFINE_FLAG(bool, enable_type_checks, false, "Enable type checks.");
 DEFINE_FLAG(bool, trace_parser, false, "Trace parser operations.");
 DEFINE_FLAG(bool, warn_mixin_typedef, true, "Warning on legacy mixin typedef.");
@@ -9564,6 +9565,10 @@
     if (target == NULL) {
       ReportError(jump_pos, "label '%s' not found", target_name.ToCString());
     }
+  } else if (FLAG_enable_debug_break && (CurrentToken() == Token::kSTRING)) {
+    const char* message = strdup(CurrentLiteral()->ToCString());

[Ivan Posva, 2015/04/16 21:44:51]

Who is responsible for freeing this memory?

[Ivan Posva, 2015/04/16 21:47:05]

Got the answer for this one: Stop does not do a strdup. It is the related
Unimplemented and similar which do allocate the final string.

[regis, 2015/04/16 22:17:04]

Yes, the strdup is necessary, since the literal string gets freed before
execution. We have many other places allocating error strings with malloc.

+    ConsumeToken();
+    return new(Z) StopNode(jump_pos, message);
   } else {
     target = current_block_->scope->LookupInnermostLabel(jump_kind);
     if (target == NULL) {
@@ -9825,7 +9830,9 @@
     ExpectToken(Token::kRBRACE);
   } else if (token == Token::kBREAK) {
     statement = ParseJump(label_name);
-    AddNodeForFinallyInlining(statement);
+    if ((statement != NULL) && !statement->IsStopNode()) {
+      AddNodeForFinallyInlining(statement);
+    }
     ExpectSemicolon();
   } else if (token == Token::kCONTINUE) {
     statement = ParseJump(label_name);