[turbofan] Implement OSR for outer loops.

src/compiler/arm64/code-generator-arm64.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/code-generator.h"
 
 #include "src/arm64/macro-assembler-arm64.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"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 #define __ masm()->
 
 
 // Adds Arm64-specific methods to convert InstructionOperands.
@@ skipping 947 matching lines @@
     __ Prologue(info->IsCodePreAgingActive());
     frame()->SetRegisterSaveAreaSize(
         StandardFrameConstants::kFixedFrameSizeFromFp);
   } else {
     __ SetStackPointer(jssp);
     __ StubPrologue();
     frame()->SetRegisterSaveAreaSize(
         StandardFrameConstants::kFixedFrameSizeFromFp);
   }
   int stack_slots = frame()->GetSpillSlotCount();
+
+  if (info()->is_osr()) {
+    // TurboFan OSR-compiled functions cannot be entered directly.
+    __ Abort(kShouldNotDirectlyEnterOsrFunction);
+
+    // 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();
+    int unoptimized_slots =
+        static_cast<int>(OsrHelper(info()).UnoptimizedFrameSlots());
+    DCHECK(stack_slots >= unoptimized_slots);
+    stack_slots -= unoptimized_slots;
+  }
+
   if (stack_slots > 0) {
     Register sp = __ StackPointer();
     if (!sp.Is(csp)) {
       __ Sub(sp, sp, stack_slots * kPointerSize);
     }
     __ Sub(csp, csp, AlignedStackSlots(stack_slots) * kPointerSize);
   }
 }
 
 
@@ skipping 191 matching lines @@
     }
   }
   MarkLazyDeoptSite();
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8