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

src/compiler.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler.h"
 
 #include <algorithm>
 #include <memory>
 
 #include "src/asmjs/asm-js.h"
@@ skipping 442 matching lines @@
   DCHECK(AllowCompilation::IsAllowed(info->isolate()));
   if (!Compiler::Analyze(info->parse_info()) ||
       !GenerateUnoptimizedCode(info)) {
     Isolate* isolate = info->isolate();
     if (!isolate->has_pending_exception()) isolate->StackOverflow();
     return false;
   }
   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());
 
   // Compile either unoptimized code or bytecode for the interpreter.
   if (!CompileUnoptimizedCode(info)) return MaybeHandle<Code>();
 
   // Record the function compilation event.
   RecordFunctionCompilation(CodeEventListener::LAZY_COMPILE_TAG, info);
 
   return info->code();
@@ skipping 484 matching lines @@
   script->set_context_data(array->get(v8::Context::kDebugIdIndex));
 
   Handle<SharedFunctionInfo> result;
 
   { VMState<COMPILER> state(info->isolate());
     if (parse_info->literal() == nullptr &&
         !parsing::ParseProgram(parse_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
     // rest of the function into account to avoid overlap with the
     // parsing statistics.
     RuntimeCallTimerScope runtimeTimer(
         isolate, parse_info->is_eval() ? &RuntimeCallStats::CompileEval
                                        : &RuntimeCallStats::Compile);
     HistogramTimer* rate = parse_info->is_eval()
                                ? info->isolate()->counters()->compile_eval()
@@ skipping 42 matching lines @@
   DCHECK_NOT_NULL(info->literal());
   if (!Rewriter::Rewrite(info)) return false;
   DeclarationScope::Analyze(info, AnalyzeMode::kRegular);
   if (!Renumber(info)) return false;
   DCHECK_NOT_NULL(info->scope());
   return true;
 }
 
 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());
   return true;
 }
 
 bool Compiler::Compile(Handle<JSFunction> function, ClearExceptionFlag flag) {
   if (function->is_compiled()) return true;
   Isolate* isolate = function->GetIsolate();
   DCHECK(AllowCompilation::IsAllowed(isolate));
@@ skipping 100 matching lines @@
   return true;
 }
 
 MaybeHandle<JSArray> Compiler::CompileForLiveEdit(Handle<Script> script) {
   Isolate* isolate = script->GetIsolate();
   DCHECK(AllowCompilation::IsAllowed(isolate));
 
   // 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);
   ParseInfo parse_info(&zone, script);
   CompilationInfo info(&parse_info, Handle<JSFunction>::null());
   info.MarkAsDebug();
 
   // TODO(635): support extensions.
   const bool compilation_succeeded = !CompileToplevel(&info).is_null();
   Handle<JSArray> infos;
@@ skipping 389 matching lines @@
 
 
 Handle<SharedFunctionInfo> Compiler::GetSharedFunctionInfo(
     FunctionLiteral* literal, Handle<Script> script,
     CompilationInfo* outer_info) {
   // Precondition: code has been parsed and scopes have been analyzed.
   Isolate* isolate = outer_info->isolate();
   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,
   // continue to decide whether to eagerly compile.
   // Note that we also carry on if we are compiling eager to obtain code for
   // debugging, unless we already have code with debug break slots.
   Handle<SharedFunctionInfo> existing;
   if (maybe_existing.ToHandle(&existing)) {
     DCHECK(!existing->is_toplevel());
     if (existing->HasBaselineCode() || existing->HasBytecodeArray()) {
       if (!outer_info->is_debug() || existing->HasDebugCode()) {
         return existing;
       }
     }
   }
 
   // Allocate a shared function info object.
   Handle<SharedFunctionInfo> result;
   if (!maybe_existing.ToHandle(&result)) {
     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);
   ParseInfo parse_info(&zone, script);
   CompilationInfo info(&parse_info, Handle<JSFunction>::null());
   parse_info.set_literal(literal);
   parse_info.set_shared_info(result);
   parse_info.set_function_literal_id(result->function_literal_id());
   parse_info.set_language_mode(literal->scope()->language_mode());
   parse_info.set_ast_value_factory(
@@ skipping 134 matching lines @@
     DCHECK(shared->is_compiled());
     function->set_literals(cached.literals);
   } else if (shared->is_compiled()) {
     // TODO(mvstanton): pass pretenure flag to EnsureLiterals.
     JSFunction::EnsureLiterals(function);
   }
 }
 
 }  // namespace internal
 }  // namespace v8