Devirtualize AstNode and subclasses, except for visiting-related methods.

src/compiler/ast-graph-builder.cc

 // Copyright 2014 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/ast-graph-builder.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
@@ skipping 2948 matching lines @@
   Visit(stmt);
 }
 
 
 void AstGraphBuilder::VisitInScope(Statement* stmt, Scope* s, Node* context) {
   ContextScope scope(this, s, context);
   DCHECK(s->declarations()->is_empty());
   Visit(stmt);
 }
 
-
+template <class IterationStatement>
 void AstGraphBuilder::VisitIterationBody(IterationStatement* stmt,
                                          LoopBuilder* loop) {
   ControlScopeForIteration scope(this, stmt, loop);
   if (FLAG_turbo_loop_stackcheck || !info()->shared_info()->asm_function()) {
     Node* node = NewNode(javascript()->StackCheck());
     PrepareFrameState(node, stmt->StackCheckId());

[Michael Starzinger, 2016/07/14 08:38:51]

I think if we were to devirtualize IterationStatement::StackCheckId() but leave
it as a member on IterationStatement and use a dispatch on the AST type in the
implementation, then this visitation method would not need to be templatized.
WDYT?

[Michael Starzinger, 2016/07/14 08:47:01]

Alternatively Jaro suggested to just pass in the "stack_check_id" as an argument
to this function. That would also work for me and even sounds a bit cleaner.

   }
   Visit(stmt->body());
 }
 
 
 void AstGraphBuilder::VisitDelete(UnaryOperation* expr) {
   Node* value;
   if (expr->expression()->IsVariableProxy()) {
     // Delete of an unqualified identifier is only allowed in classic mode but
     // deleting "this" is allowed in all language modes.
@@ skipping 1383 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8