[turbofan] Implement OSR for outer loops.

src/compiler/ia32/code-generator-ia32.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/ia32/assembler-ia32.h"
 #include "src/ia32/macro-assembler-ia32.h"
 #include "src/scopes.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 #define __ masm()->
 
@@ skipping 995 matching lines @@
     if (saves != 0) {  // Save callee-saved registers.
       int register_save_area_size = 0;
       for (int i = Register::kNumRegisters - 1; i >= 0; i--) {
         if (!((1 << i) & saves)) continue;
         __ push(Register::from_code(i));
         register_save_area_size += kPointerSize;
       }
       frame->SetRegisterSaveAreaSize(register_save_area_size);
     }
   } else if (descriptor->IsJSFunctionCall()) {
+    // TODO(turbofan): this prologue is redundant with OSR, but needed for
+    // code aging.
     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.
+    __ 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) {
+    // Allocate the stack slots used by this frame.
     __ sub(esp, Immediate(stack_slots * kPointerSize));
   }
 }
 
 
 void CodeGenerator::AssembleReturn() {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
   if (descriptor->kind() == CallDescriptor::kCallAddress) {
     const RegList saves = descriptor->CalleeSavedRegisters();
     if (frame()->GetRegisterSaveAreaSize() > 0) {
@@ skipping 199 matching lines @@
     }
   }
   MarkLazyDeoptSite();
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8