[turbofan] Implement OSR for outer loops.

src/compiler/linkage-impl.h

 // 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.
 
 #ifndef V8_COMPILER_LINKAGE_IMPL_H_
 #define V8_COMPILER_LINKAGE_IMPL_H_
 
 #include "src/code-stubs.h"
+#include "src/compiler/osr.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 // TODO(titzer): replace uses of int with size_t in LinkageHelper.
 template <typename LinkageTraits>
 class LinkageHelper {
  public:
   static const RegList kNoCalleeSaved = 0;
@@ skipping 200 matching lines @@
 
   static LinkageLocation regloc(Register reg) {
     return LinkageLocation(Register::ToAllocationIndex(reg));
   }
 
   static LinkageLocation stackloc(int i) {
     DCHECK_LT(i, 0);
     return LinkageLocation(i);
   }
 };
+
+
+LinkageLocation Linkage::GetOsrValueLocation(int index) const {
+  CHECK(incoming_->IsJSFunctionCall());
+  int parameter_count = static_cast<int>(incoming_->JSParameterCount() - 1);
+  int first_stack_slot = OsrHelper::FirstStackSlotIndex(parameter_count);
+
+  if (index >= first_stack_slot) {
+    // Local variable stored in this (callee) stack.
+    int spill_index =
+        LinkageLocation::ANY_REGISTER + 1 + index - first_stack_slot;
+    // TODO(titzer): bailout instead of crashing here.
+    CHECK(spill_index <= LinkageLocation::MAX_STACK_SLOT);
+    return LinkageLocation(spill_index);
+  } else {
+    // Parameter. Use the assigned location from the incoming call descriptor.
+    int parameter_index = 1 + index;  // skip index 0, which is the target.
+    return incoming_->GetInputLocation(parameter_index);
+  }
+}
+
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_LINKAGE_IMPL_H_