[turbofan] Implement OSR for outer loops.

src/compiler/x64/code-generator-x64.cc

 // Copyright 2013 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/code-generator.h"
 
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties-inl.h"
+#include "src/compiler/osr.h"
 #include "src/scopes.h"
 #include "src/x64/assembler-x64.h"
 #include "src/x64/macro-assembler-x64.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 #define __ masm()->
 
@@ skipping 1196 matching lines @@
   } else if (descriptor->IsJSFunctionCall()) {
     CompilationInfo* info = this->info();
     __ Prologue(info->IsCodePreAgingActive());
     frame()->SetRegisterSaveAreaSize(
         StandardFrameConstants::kFixedFrameSizeFromFp);
   } else {
     __ StubPrologue();
     frame()->SetRegisterSaveAreaSize(
         StandardFrameConstants::kFixedFrameSizeFromFp);
   }
+
+  if (info()->is_osr()) {
+    // TurboFan OSR-compiled functions cannot be entered directly.
+    __ int3();
+
+    // Unoptimized code jumps directly to this entrypoint while the unoptimized
+    // frame is still on the stack. Optimized code uses OSR values directly from
+    // the unoptimized frame. Thus, all that needs to be done is to allocate the
+    // remaining stack slots.
+    if (FLAG_code_comments) __ RecordComment("-- OSR entrypoint --");
+    osr_pc_offset_ = __ pc_offset();
+    size_t unoptimized_slots = OsrHelper(info()).UnoptimizedFrameSlots();
+    DCHECK(stack_slots >= static_cast<int>(unoptimized_slots));
+    stack_slots -= unoptimized_slots;
+  }
+
   if (stack_slots > 0) {
     __ subq(rsp, Immediate(stack_slots * kPointerSize));
   }
 }
 
 
 void CodeGenerator::AssembleReturn() {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
   if (descriptor->kind() == CallDescriptor::kCallAddress) {
     if (frame()->GetRegisterSaveAreaSize() > 0) {
@@ skipping 200 matching lines @@
     }
   }
   MarkLazyDeoptSite();
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace compiler
 }  // namespace v8