VM: Add infrastructure to support deferred generation of unoptimized code.

runtime/vm/compiler.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/block_scheduler.h"
@@ skipping 955 matching lines @@
                                        intptr_t osr_id) {
   Thread* volatile thread = Thread::Current();
   Isolate* volatile isolate = thread->isolate();
   StackZone stack_zone(isolate);
   Zone* volatile zone = stack_zone.GetZone();
   LongJumpScope jump;
   if (setjmp(*jump.Set()) == 0) {
     TIMERSCOPE(isolate, time_compilation);
     Timer per_compile_timer(FLAG_trace_compiler, "Compilation time");
     per_compile_timer.Start();
+
     ParsedFunction* parsed_function = new(zone) ParsedFunction(
         thread, Function::ZoneHandle(zone, function.raw()));
     if (FLAG_trace_compiler) {
       ISL_Print("Compiling %s%sfunction: '%s' @ token %" Pd ", size %" Pd "\n",
                 (osr_id == Isolate::kNoDeoptId ? "" : "osr "),
                 (optimized ? "optimized " : ""),
                 function.ToFullyQualifiedCString(),
                 function.token_pos(),
                 (function.end_token_pos() - function.token_pos()));
     }
@@ skipping 59 matching lines @@
 
 RawError* Compiler::CompileFunction(Thread* thread,
                                     const Function& function) {
   VMTagScope tagScope(thread->isolate(), VMTag::kCompileUnoptimizedTagId);
   CompilationPipeline* pipeline =
       CompilationPipeline::New(thread->zone(), function);
   return CompileFunctionHelper(pipeline, function, false, Isolate::kNoDeoptId);
 }
 
 
+void Compiler::EnsureUnoptimizedCode(Thread* thread,
+                                     const Function& function) {
+  if (function.unoptimized_code() != Object::null()) {
+    return;
+  }
+  Code& original_code = Code::ZoneHandle();

[srdjan, 2015/04/02 17:43:40]

pass thread->zone() to it.

[Florian Schneider, 2015/04/07 09:07:57]

Done.

+  if (function.HasCode()) {
+    original_code = function.CurrentCode();
+  }
+  CompilationPipeline* pipeline =
+      CompilationPipeline::New(thread->zone(), function);
+  const Error& error = Error::Handle(
+      CompileFunctionHelper(pipeline, function, false, Isolate::kNoDeoptId));
+  if (!error.IsNull()) {
+    Exceptions::PropagateError(error);
+  }
+  if (!original_code.IsNull() &&

[Ivan Posva, 2015/04/02 17:14:00]

This logic here is really hard to follow. Please explain what the intent is here
in a comment.

[Florian Schneider, 2015/04/07 09:07:57]

Done.

+      (original_code.raw() != function.CurrentCode())) {
+    function.AttachCode(original_code);
+  }
+  ASSERT(function.unoptimized_code() != Object::null());
+  if (FLAG_trace_compiler) {
+    ISL_Print("Ensure unoptimized code for %s\n", function.ToCString());
+  }
+}
+
+
 RawError* Compiler::CompileOptimizedFunction(Thread* thread,
                                              const Function& function,
                                              intptr_t osr_id) {
   VMTagScope tagScope(thread->isolate(), VMTag::kCompileOptimizedTagId);
   CompilationPipeline* pipeline =
       CompilationPipeline::New(thread->zone(), function);
   return CompileFunctionHelper(pipeline, function, true, osr_id);
 }
 
 
@@ skipping 166 matching lines @@
     const Object& result =
       PassiveObject::Handle(isolate->object_store()->sticky_error());
     isolate->object_store()->clear_sticky_error();
     return result.raw();
   }
   UNREACHABLE();
   return Object::null();
 }
 
 }  // namespace dart