[es6] Tail calls support.

src/x64/macro-assembler-x64.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 4009 matching lines @@
 void MacroAssembler::DebugBreak() {
   Set(rax, 0);  // No arguments.
   LoadAddress(rbx,
               ExternalReference(Runtime::kHandleDebuggerStatement, isolate()));
   CEntryStub ces(isolate(), 1);
   DCHECK(AllowThisStubCall(&ces));
   Call(ces.GetCode(), RelocInfo::DEBUGGER_STATEMENT);
 }
 
 
+//
+// Stack structure for the function g() tail calling f():
+//
+// ------- Caller frame: -------
+// |  ...
+// |  g()'s arg M
+// |  ...
+// |  g()'s arg 1
+// |  g()'s receiver arg
+// |  g()'s caller pc
+// ------- g()'s frame: -------
+// |  g()'s caller fp      <- fp
+// |  g()'s context
+// |  function pointer: g
+// |  -------------------------
+// |  ...
+// |  ...
+// |  f()'s arg N
+// |  ...
+// |  f()'s arg 1
+// |  f()'s receiver arg
+// |  f()'s caller pc      <- sp
+// ----------------------
+//
+void MacroAssembler::DropCurrentJSFrame(Register args_reg, Register scratch1,
+                                        Register scratch2, Register scratch3) {
+  DCHECK(!AreAliased(args_reg, scratch1, scratch2, scratch3));
+
+  Label no_arguments_adaptor, formal_parameter_count_loaded;
+  // TODO(ishell): check for arguments adaptor frame presence
+  movp(scratch2, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
+  Cmp(Operand(scratch2, StandardFrameConstants::kContextOffset),
+      Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
+  j(not_equal, &no_arguments_adaptor, Label::kNear);
+
+  // Drop arguments adaptor frame and load arguments count.
+  movp(rbp, scratch2);
+  SmiToInteger32(scratch1,
+                 Operand(rbp, ArgumentsAdaptorFrameConstants::kLengthOffset));
+  jmp(&formal_parameter_count_loaded, Label::kNear);
+
+  bind(&no_arguments_adaptor);
+  // Load caller's formal parameter count
+  movp(scratch1, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
+  movp(scratch1, FieldOperand(scratch1, JSFunction::kSharedFunctionInfoOffset));
+  LoadSharedFunctionInfoSpecialField(
+      scratch1, scratch1, SharedFunctionInfo::kFormalParameterCountOffset);
+
+  bind(&formal_parameter_count_loaded);
+
+  // Calculate the destination address where we will put the return address
+  // after we drop current frame.
+  Register new_sp_reg = scratch2;
+  subp(scratch1, args_reg);
+  leap(new_sp_reg, Operand(rbp, scratch1, times_pointer_size,
+                           StandardFrameConstants::kCallerPCOffset));
+
+  if (emit_debug_code()) {
+    cmpp(rsp, new_sp_reg);
+    Check(below, kStackAccessBelowStackPointer);
+  }
+
+  // Copy receiver and return address as well.
+  Register count_reg = scratch1;
+  leap(count_reg, Operand(args_reg, 2));
+
+  // Copy return address from caller's frame to current frame's return address
+  // to avoid its trashing and let the following loop copy it to the right
+  // place.
+  Register tmp_reg = scratch3;
+  movp(tmp_reg, Operand(rbp, StandardFrameConstants::kCallerPCOffset));
+  movp(Operand(rsp, 0), tmp_reg);
+
+  // Restore caller's frame pointer now as it could be overwritten by
+  // the copying loop.
+  movp(rbp, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
+
+  Operand src(rsp, count_reg, times_pointer_size, 0);
+  Operand dst(new_sp_reg, count_reg, times_pointer_size, 0);
+
+  // Now copy callee arguments to the caller frame going backwards to avoid
+  // callee arguments corruption (source and destination areas could overlap).
+  Label loop, entry;
+  jmp(&entry, Label::kNear);
+  bind(&loop);
+  decp(count_reg);
+  movp(tmp_reg, src);
+  movp(dst, tmp_reg);
+  bind(&entry);
+  cmpp(count_reg, Immediate(0));
+  j(not_equal, &loop, Label::kNear);
+
+  // Leave current frame.
+  movp(rsp, new_sp_reg);
+}
+
+
 void MacroAssembler::InvokeFunction(Register function,
                                     Register new_target,
                                     const ParameterCount& actual,
                                     InvokeFlag flag,
                                     const CallWrapper& call_wrapper) {
   movp(rbx, FieldOperand(function, JSFunction::kSharedFunctionInfoOffset));
   LoadSharedFunctionInfoSpecialField(
       rbx, rbx, SharedFunctionInfo::kFormalParameterCountOffset);
 
   ParameterCount expected(rbx);
@@ skipping 1036 matching lines @@
   }
 
   bind(&done);
 }
 
 
 void MacroAssembler::InitializeFieldsWithFiller(Register current_address,
                                                 Register end_address,
                                                 Register filler) {
   Label loop, entry;
-  jmp(&entry);
+  jmp(&entry, Label::kNear);
   bind(&loop);
   movp(Operand(current_address, 0), filler);
   addp(current_address, Immediate(kPointerSize));
   bind(&entry);
   cmpp(current_address, end_address);
-  j(below, &loop);
+  j(below, &loop, Label::kNear);
 }
 
 
 void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
   if (context_chain_length > 0) {
     // Move up the chain of contexts to the context containing the slot.
     movp(dst, Operand(rsi, Context::SlotOffset(Context::PREVIOUS_INDEX)));
     for (int i = 1; i < context_chain_length; i++) {
       movp(dst, Operand(dst, Context::SlotOffset(Context::PREVIOUS_INDEX)));
     }
@@ skipping 407 matching lines @@
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64