Add flow graph printing into a .cfg file with flag --print-flow-graph-file.

bin/main.cc

Index: bin/main.cc
===================================================================
--- bin/main.cc	(revision 8145)
+++ bin/main.cc	(working copy)
@@ -39,6 +39,10 @@
 static const char* generate_pprof_symbols_filename = NULL;
 
 
+// Global state that stores a file name for flow graph debugging output.
+// NULL if no output is generated.
+static File* flow_graph_file = NULL;
+
 // Global state that indicates whether there is a debug breakpoint.
 // This pointer points into an argv buffer and does not need to be
 // free'd.
@@ -129,6 +133,13 @@
 }
 
 
+static void ProcessFlowGraphOption(const char* flowgraph_option) {
+  ASSERT(flowgraph_option != NULL);
+  flow_graph_file = File::Open("flowgraph.cfg", File::kWriteTruncate);
+  ASSERT(flow_graph_file != NULL);

[siva, 2012/06/04 18:23:57]

Where is flow_graph_file closed?

[Florian Schneider, 2012/06/06 11:06:10]

At process exit.  I could close it explicitly right before every possible exit
of main() which is currently in four different places.  Since it is only opened
when the --generate-flow-graph flag is on, I prefer not explicitly closing it
for conciseness.

[siva, 2012/06/06 17:02:47]

I disagree, correctness not conciseness is the yardstick to use. If a file is
opened it needs to be closed properly. You cannot rely on process exit doing the
right thing here.

Especially if you create these files on a per isolate basis then you should
close them when shutting down the isolate.


On 2012/06/06 11:06:10, Florian Schneider wrote:

[Florian Schneider, 2012/06/07 09:32:26]

I view this as an experimental flag.

How about abnormal exit (SIGSEGV, SIGTERM, SIGKILL, etc.) then? We rely the
OS/library to clean up in this case.

+}
+
+
 static void ProcessImportMapOption(const char* map) {
   ASSERT(map != NULL);
   import_map_options->AddArgument(map);
@@ -145,6 +156,7 @@
   { "--generate_pprof_symbols=", ProcessPprofOption },
   { "--import_map=", ProcessImportMapOption },
   { "--package-root=", ProcessPackageRootOption },
+  { "--generate_flow_graph", ProcessFlowGraphOption },
   { NULL, NULL }
 };
 
@@ -165,6 +177,12 @@
 }
 
 
+static void WriteToFlowGraphFile(const char* buffer, int64_t num_bytes) {
+  ASSERT(flow_graph_file != NULL);
+  flow_graph_file->WriteFully(buffer, num_bytes);
+}
+
+
 // Parse out the command line arguments. Returns -1 if the arguments
 // are incorrect, 0 otherwise.
 static int ParseArguments(int argc,
@@ -195,6 +213,10 @@
     Dart_InitPprofSupport();
   }
 
+  if (flow_graph_file != NULL) {
+    Dart_InitFlowGraphPrinting(&WriteToFlowGraphFile);
+  }
+
   // Get the script name.
   if (i < argc) {
     *script_name = argv[i];