Assign yield ids in ast-numbering rather than in bytecode-generator.

src/interpreter/bytecode-generator.cc

 // Copyright 2015 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/interpreter/bytecode-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-register-allocator.h"
 #include "src/interpreter/control-flow-builders.h"
@@ skipping 552 matching lines @@
           info->scope()->num_stack_slots(), info->literal())),
       info_(info),
       scope_(info->scope()),
       globals_(0, info->zone()),
       execution_control_(nullptr),
       execution_context_(nullptr),
       execution_result_(nullptr),
       register_allocator_(nullptr),
       generator_resume_points_(info->literal()->yield_count(), info->zone()),
       generator_state_(),
-      generator_yields_seen_(0),
       try_catch_nesting_level_(0),
       try_finally_nesting_level_(0) {
   InitializeAstVisitor(isolate());
 }
 
 Handle<BytecodeArray> BytecodeGenerator::MakeBytecode() {
   // Initialize the incoming context.
   ContextScope incoming_context(this, scope(), false);
 
   // Initialize control scope.
@@ skipping 76 matching lines @@
 
 void BytecodeGenerator::VisitIterationHeader(IterationStatement* stmt,
                                              LoopBuilder* loop_builder) {
   // Recall that stmt->yield_count() is always zero inside ordinary
   // (i.e. non-generator) functions.
 
   // Collect all labels for generator resume points within the loop (if any) so
   // that they can be bound to the loop header below. Also create fresh labels
   // for these resume points, to be used inside the loop.
   ZoneVector<BytecodeLabel> resume_points_in_loop(zone());
-  for (size_t id = generator_yields_seen_;
-       id < generator_yields_seen_ + stmt->yield_count(); id++) {
+  size_t first = stmt->first_yield_id();

[Jarin, 2016/04/28 16:31:18]

I am mildly surprised this works is not first_yield_id an integer?

[neis, 2016/04/29 07:52:24]

signed to unsigned is always "fine" as far as I know

+  for (size_t id = first; id < first + stmt->yield_count(); id++) {
     DCHECK(0 <= id && id < generator_resume_points_.size());
     auto& label = generator_resume_points_[id];
     resume_points_in_loop.push_back(label);
     generator_resume_points_[id] = BytecodeLabel();
   }
 
   loop_builder->LoopHeader(&resume_points_in_loop);
 
   if (stmt->yield_count() > 0) {
     // If we are not resuming, fall through to loop body.
     // If we are resuming, perform state dispatch.
     BytecodeLabel not_resuming;
     builder()
         ->LoadLiteral(Smi::FromInt(JSGeneratorObject::kGeneratorExecuting))
         .CompareOperation(Token::Value::EQ, generator_state_)
         .JumpIfTrue(&not_resuming);
-    BuildIndexedJump(generator_state_, generator_yields_seen_,
-                     stmt->yield_count(), generator_resume_points_);
+    BuildIndexedJump(
+        generator_state_, first, stmt->yield_count(), generator_resume_points_);
     builder()->Bind(&not_resuming);
   }
 }
 
 void BytecodeGenerator::VisitGeneratorPrologue() {
   // The generator resume trampoline abuses the new.target register both to
   // indicate that this is a resume call and to pass in the generator object.
   // In ordinary calls, new.target is always undefined because generator
   // functions are non-constructable.
   Register generator_object = Register::new_target();
@@ skipping 1559 matching lines @@
     case KEYED_SUPER_PROPERTY: {
       builder()->StoreAccumulatorInRegister(value);
       BuildKeyedSuperPropertyStore(object, home_object, key, value);
       break;
     }
   }
   execution_result()->SetResultInAccumulator();
 }
 
 void BytecodeGenerator::VisitYield(Yield* expr) {
-  size_t id = generator_yields_seen_++;
-
   builder()->SetExpressionPosition(expr);
   Register value = VisitForRegisterValue(expr->expression());
 
   Register generator = VisitForRegisterValue(expr->generator_object());
 
   // Save context, registers, and state. Then return.
   builder()
-      ->LoadLiteral(Smi::FromInt(static_cast<int>(id)))
+      ->LoadLiteral(Smi::FromInt(expr->id()))
       .SuspendGenerator(generator)
       .LoadAccumulatorWithRegister(value)
       .Return();  // Hard return (ignore any finally blocks).
 
-  builder()->Bind(&(generator_resume_points_[id]));
+  builder()->Bind(&(generator_resume_points_[expr->id()]));
   // Upon resume, we continue here.
 
   {
     RegisterAllocationScope register_scope(this);
 
     // Update state to indicate that we have finished resuming. Loop headers
     // rely on this.
     builder()
         ->LoadLiteral(Smi::FromInt(JSGeneratorObject::kGeneratorExecuting))
         .StoreAccumulatorInRegister(generator_state_);
@@ skipping 977 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->shared_info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8