[turbofan] Introduce JSStackCheck operator.

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/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/linkage.h"
@@ skipping 2948 matching lines @@
       break;
     default:
       UNREACHABLE();
       js_op = NULL;
   }
   return NewNode(js_op, left, right);
 }
 
 
 Node* AstGraphBuilder::BuildStackCheck() {
-  IfBuilder stack_check(this);
-  Node* limit = BuildLoadExternal(
-      ExternalReference::address_of_stack_limit(isolate()), kMachPtr);
-  Node* stack = NewNode(jsgraph()->machine()->LoadStackPointer());
-  Node* tag = NewNode(jsgraph()->machine()->UintLessThan(), limit, stack);
-  stack_check.If(tag, BranchHint::kTrue);
-  stack_check.Then();
-  stack_check.Else();
-  Node* guard = NewNode(javascript()->CallRuntime(Runtime::kStackGuard, 0));
-  stack_check.End();
-  return guard;
+  return NewNode(javascript()->StackCheck());

[Michael Starzinger, 2015/03/06 14:06:39]

nit: I think we can now inline this into CreateGraphBody. WDYT?

[Benedikt Meurer, 2015/03/09 05:01:45]

Indeed.

 }
 
 
 bool AstGraphBuilder::CheckOsrEntry(IterationStatement* stmt) {
   if (info()->osr_ast_id() == stmt->OsrEntryId()) {
     info()->set_osr_expr_stack_height(std::max(
         environment()->stack_height(), info()->osr_expr_stack_height()));
     return true;
   }
   return false;
@@ skipping 292 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