[runtime] Change MessageLocation::function to SFI.

This changes the {MessageLocation} structure to no longer contain a
concrete {JSFunction} object but rather a {SharedFunctionInfo}. It is
much easier by now to determine, and also the concrete closure is never
actually being used.

R=yangguo@chromium.org

Review-Url: https://codereview.chromium.org/2628973005
Cr-Commit-Position: refs/heads/master@{#42324}

src/isolate.cc

@@ -1503,7 +1503,7 @@ bool Isolate::ComputeLocation(MessageLocation* target) {
   frame->Summarize(&frames);
   FrameSummary& summary = frames.last();
   int pos = summary.SourcePosition();
-  Handle<JSFunction> fun;
+  Handle<SharedFunctionInfo> shared;
   Handle<Object> script = summary.script();
   if (!script->IsScript() ||
       (Script::cast(*script)->source()->IsUndefined(this))) {
@@ -1515,8 +1515,10 @@ bool Isolate::ComputeLocation(MessageLocation* target) {
   // incomplete (see bug v8:5007).
   if (summary.IsWasmCompiled() && !FLAG_wasm_trap_if) return false;
 
-  if (summary.IsJavaScript()) fun = summary.AsJavaScript().function();
-  *target = MessageLocation(Handle<Script>::cast(script), pos, pos + 1, fun);
+  if (summary.IsJavaScript()) {
+    shared = handle(summary.AsJavaScript().function()->shared());
+  }
+  *target = MessageLocation(Handle<Script>::cast(script), pos, pos + 1, shared);
   return true;
 }
 

src/messages.cc

@@ -21,11 +21,11 @@ MessageLocation::MessageLocation(Handle<Script> script, int start_pos,
                                  int end_pos)
     : script_(script), start_pos_(start_pos), end_pos_(end_pos) {}
 MessageLocation::MessageLocation(Handle<Script> script, int start_pos,
-                                 int end_pos, Handle<JSFunction> function)
+                                 int end_pos, Handle<SharedFunctionInfo> shared)
     : script_(script),
       start_pos_(start_pos),
       end_pos_(end_pos),
-      function_(function) {}
+      shared_(shared) {}
 MessageLocation::MessageLocation() : start_pos_(-1), end_pos_(-1) {}
 
 // If no message listeners have been registered this one is called

src/messages.h

@@ -23,25 +23,26 @@ class AbstractCode;
 class FrameArray;
 class JSMessageObject;
 class LookupIterator;
+class SharedFunctionInfo;
 class SourceInfo;
 
 class MessageLocation {
  public:
   MessageLocation(Handle<Script> script, int start_pos, int end_pos);
   MessageLocation(Handle<Script> script, int start_pos, int end_pos,
-                  Handle<JSFunction> function);
+                  Handle<SharedFunctionInfo> shared);
   MessageLocation();
 
   Handle<Script> script() const { return script_; }
   int start_pos() const { return start_pos_; }
   int end_pos() const { return end_pos_; }
-  Handle<JSFunction> function() const { return function_; }
+  Handle<SharedFunctionInfo> shared() const { return shared_; }
 
  private:
   Handle<Script> script_;
   int start_pos_;
   int end_pos_;
-  Handle<JSFunction> function_;
+  Handle<SharedFunctionInfo> shared_;
 };
 
 class StackFrameBase {

src/runtime/runtime-internal.cc

@@ -333,13 +333,13 @@ bool ComputeLocation(Isolate* isolate, MessageLocation* target) {
     List<FrameSummary> frames(FLAG_max_inlining_levels + 1);
     it.frame()->Summarize(&frames);
     auto& summary = frames.last().AsJavaScript();
-    Handle<JSFunction> function = summary.function();
-    Handle<Object> script(function->shared()->script(), isolate);
+    Handle<SharedFunctionInfo> shared(summary.function()->shared());
+    Handle<Object> script(shared->script(), isolate);
     int pos = summary.abstract_code()->SourcePosition(summary.code_offset());
     if (script->IsScript() &&
         !(Handle<Script>::cast(script)->source()->IsUndefined(isolate))) {
       Handle<Script> casted_script = Handle<Script>::cast(script);
-      *target = MessageLocation(casted_script, pos, pos + 1, function);
+      *target = MessageLocation(casted_script, pos, pos + 1, shared);
       return true;
     }
   }
@@ -351,11 +351,9 @@ Handle<String> RenderCallSite(Isolate* isolate, Handle<Object> object) {
   MessageLocation location;
   if (ComputeLocation(isolate, &location)) {
     Zone zone(isolate->allocator(), ZONE_NAME);
-    std::unique_ptr<ParseInfo> info(
-        new ParseInfo(&zone, handle(location.function()->shared())));
+    std::unique_ptr<ParseInfo> info(new ParseInfo(&zone, location.shared()));
     if (parsing::ParseAny(info.get())) {
-      CallPrinter printer(isolate,
-                          location.function()->shared()->IsUserJavaScript());
+      CallPrinter printer(isolate, location.shared()->IsUserJavaScript());
       Handle<String> str = printer.Print(info->literal(), location.start_pos());
       if (str->length() > 0) return str;
     } else {