Reland of "Store SharedFunctionInfos of a Script in a FixedArray indexed by their ID"

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index b8fbbcfa2c31dea9d7fc002d6dcc7389d096ee65..da440f019c18dd190e8eaa8afe5e13384a0c5aaa 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -460,12 +460,29 @@ bool CompileUnoptimizedCode(CompilationInfo* info) {
   return true;
 }
 
+void EnsureSharedFunctionInfosArrayOnScript(ParseInfo* info) {
+  DCHECK(info->is_toplevel());
+  DCHECK(!info->script().is_null());
+  if (info->script()->shared_function_infos()->length() > 0) {
+    DCHECK_EQ(info->script()->shared_function_infos()->length(),
+              info->max_function_literal_id() + 1);
+    return;
+  }
+  Isolate* isolate = info->isolate();
+  Handle<FixedArray> infos(
+      isolate->factory()->NewFixedArray(info->max_function_literal_id() + 1));
+  info->script()->set_shared_function_infos(*infos);
+}
+
 MUST_USE_RESULT MaybeHandle<Code> GetUnoptimizedCode(CompilationInfo* info) {
   VMState<COMPILER> state(info->isolate());
   PostponeInterruptsScope postpone(info->isolate());
 
   // Parse and update CompilationInfo with the results.
   if (!parsing::ParseAny(info->parse_info())) return MaybeHandle<Code>();
+  if (info->parse_info()->is_toplevel()) {
+    EnsureSharedFunctionInfosArrayOnScript(info->parse_info());
+  }
   DCHECK_EQ(info->shared_info()->language_mode(),
             info->literal()->language_mode());
 
@@ -970,6 +987,8 @@ Handle<SharedFunctionInfo> CompileToplevel(CompilationInfo* info) {
       return Handle<SharedFunctionInfo>::null();
     }
 
+    EnsureSharedFunctionInfosArrayOnScript(parse_info);
+
     FunctionLiteral* lit = parse_info->literal();
 
     // Measure how long it takes to do the compilation; only take the
@@ -1032,6 +1051,7 @@ bool Compiler::Analyze(ParseInfo* info) {
 
 bool Compiler::ParseAndAnalyze(ParseInfo* info) {
   if (!parsing::ParseAny(info)) return false;
+  if (info->is_toplevel()) EnsureSharedFunctionInfosArrayOnScript(info);
   if (!Compiler::Analyze(info)) return false;
   DCHECK_NOT_NULL(info->literal());
   DCHECK_NOT_NULL(info->scope());
@@ -1152,8 +1172,9 @@ MaybeHandle<JSArray> Compiler::CompileForLiveEdit(Handle<Script> script) {
   // In order to ensure that live edit function info collection finds the newly
   // generated shared function infos, clear the script's list temporarily
   // and restore it at the end of this method.
-  Handle<Object> old_function_infos(script->shared_function_infos(), isolate);
-  script->set_shared_function_infos(Smi::kZero);
+  Handle<FixedArray> old_function_infos(script->shared_function_infos(),
+                                        isolate);
+  script->set_shared_function_infos(isolate->heap()->empty_fixed_array());
 
   // Start a compilation.
   Zone zone(isolate->allocator(), ZONE_NAME);
@@ -1563,15 +1584,7 @@ Handle<SharedFunctionInfo> Compiler::GetSharedFunctionInfo(
   MaybeHandle<SharedFunctionInfo> maybe_existing;
 
   // Find any previously allocated shared function info for the given literal.
-  if (outer_info->shared_info()->never_compiled()) {
-    // On the first compile, there are no existing shared function info for
-    // inner functions yet, so do not try to find them. All bets are off for
-    // live edit though.
-    SLOW_DCHECK(script->FindSharedFunctionInfo(literal).is_null() ||
-                isolate->debug()->live_edit_enabled());
-  } else {
-    maybe_existing = script->FindSharedFunctionInfo(literal);
-  }
+  maybe_existing = script->FindSharedFunctionInfo(isolate, literal);
 
   // We found an existing shared function info. If it has any sort of code
   // attached, don't worry about compiling and simply return it. Otherwise,
@@ -1594,11 +1607,6 @@ Handle<SharedFunctionInfo> Compiler::GetSharedFunctionInfo(
     result =
         isolate->factory()->NewSharedFunctionInfoForLiteral(literal, script);
     result->set_is_toplevel(false);
-
-    // If the outer function has been compiled before, we cannot be sure that
-    // shared function info for this function literal has been created for the
-    // first time. It may have already been compiled previously.
-    result->set_never_compiled(outer_info->shared_info()->never_compiled());
   }
 
   Zone zone(isolate->allocator(), ZONE_NAME);