Debugger: move implementation to a separate folder.

src/arm64/debug-arm64.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/v8.h"
-
-#if V8_TARGET_ARCH_ARM64
-
-#include "src/codegen.h"
-#include "src/debug.h"
-
-namespace v8 {
-namespace internal {
-
-#define __ ACCESS_MASM(masm)
-
-
-void EmitDebugBreakSlot(Assembler* masm) {
-  Label check_size;
-  __ bind(&check_size);
-  for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
-    __ nop(Assembler::DEBUG_BREAK_NOP);
-  }
-  DCHECK_EQ(Assembler::kDebugBreakSlotInstructions,
-            static_cast<int>(masm->InstructionsGeneratedSince(&check_size)));
-}
-
-
-void DebugCodegen::GenerateSlot(MacroAssembler* masm, RelocInfo::Mode mode,
-                                int call_argc) {
-  // Generate enough nop's to make space for a call instruction. Avoid emitting
-  // the constant pool in the debug break slot code.
-  InstructionAccurateScope scope(masm, Assembler::kDebugBreakSlotInstructions);
-  masm->RecordDebugBreakSlot(mode, call_argc);
-  EmitDebugBreakSlot(masm);
-}
-
-
-void DebugCodegen::ClearDebugBreakSlot(Address pc) {
-  PatchingAssembler patcher(reinterpret_cast<Instruction*>(pc),
-                            Assembler::kDebugBreakSlotInstructions);
-  EmitDebugBreakSlot(&patcher);
-}
-
-
-void DebugCodegen::PatchDebugBreakSlot(Address pc, Handle<Code> code) {
-  DCHECK_EQ(Code::BUILTIN, code->kind());
-  PatchingAssembler patcher(reinterpret_cast<Instruction*>(pc),
-                            Assembler::kDebugBreakSlotInstructions);
-  // Patch the code emitted by DebugCodegen::GenerateSlots, changing the debug
-  // break slot code from
-  //   mov x0, x0    @ nop DEBUG_BREAK_NOP
-  //   mov x0, x0    @ nop DEBUG_BREAK_NOP
-  //   mov x0, x0    @ nop DEBUG_BREAK_NOP
-  //   mov x0, x0    @ nop DEBUG_BREAK_NOP
-  //   mov x0, x0    @ nop DEBUG_BREAK_NOP
-  // to a call to the debug slot code.
-  //   ldr ip0, [pc, #(2 * kInstructionSize)]
-  //   blr ip0
-  //   b skip
-  //   <debug break slot code entry point address (64 bits)>
-  //   skip:
-
-  Label skip_constant;
-  // The first instruction of a patched debug break slot must be a load literal
-  // loading the address of the debug break slot code.
-  patcher.ldr_pcrel(ip0, (2 * kInstructionSize) >> kLoadLiteralScaleLog2);
-  patcher.b(&skip_constant);
-  patcher.dc64(reinterpret_cast<int64_t>(code->entry()));
-  patcher.bind(&skip_constant);
-  // TODO(all): check the following is correct.
-  // The debug break slot code will push a frame and call statically compiled
-  // code. By using blr,  this call site will be registered in the frame.
-  // The debugger can now iterate on the frames to find this call.
-  patcher.blr(ip0);
-}
-
-
-void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
-                                          DebugBreakCallHelperMode mode) {
-  __ RecordComment("Debug break");
-  Register scratch = x10;
-  {
-    FrameScope scope(masm, StackFrame::INTERNAL);
-
-    // Load padding words on stack.
-    __ Mov(scratch, Smi::FromInt(LiveEdit::kFramePaddingValue));
-    __ PushMultipleTimes(scratch, LiveEdit::kFramePaddingInitialSize);
-    __ Mov(scratch, Smi::FromInt(LiveEdit::kFramePaddingInitialSize));
-    __ Push(scratch);
-
-    if (mode == SAVE_RESULT_REGISTER) __ Push(x0);
-
-    __ Mov(x0, 0);  // No arguments.
-    __ Mov(x1, ExternalReference(Runtime::FunctionForId(Runtime::kDebugBreak),
-                                 masm->isolate()));
-
-    CEntryStub stub(masm->isolate(), 1);
-    __ CallStub(&stub);
-
-    if (FLAG_debug_code) {
-      for (int i = 0; i < kNumJSCallerSaved; i++) {
-        Register reg = Register::XRegFromCode(JSCallerSavedCode(i));
-        __ Mov(reg, Operand(kDebugZapValue));
-      }
-    }
-
-    // Restore the register values from the expression stack.
-    if (mode == SAVE_RESULT_REGISTER) __ Pop(x0);
-
-    // Don't bother removing padding bytes pushed on the stack
-    // as the frame is going to be restored right away.
-
-    // Leave the internal frame.
-  }
-
-  // Now that the break point has been handled, resume normal execution by
-  // jumping to the target address intended by the caller and that was
-  // overwritten by the address of DebugBreakXXX.
-  ExternalReference after_break_target =
-      ExternalReference::debug_after_break_target_address(masm->isolate());
-  __ Mov(scratch, after_break_target);
-  __ Ldr(scratch, MemOperand(scratch));
-  __ Br(scratch);
-}
-
-
-void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
-  __ Ret();
-}
-
-
-void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
-  ExternalReference restarter_frame_function_slot =
-      ExternalReference::debug_restarter_frame_function_pointer_address(
-          masm->isolate());
-  UseScratchRegisterScope temps(masm);
-  Register scratch = temps.AcquireX();
-
-  __ Mov(scratch, restarter_frame_function_slot);
-  __ Str(xzr, MemOperand(scratch));
-
-  // We do not know our frame height, but set sp based on fp.
-  __ Sub(masm->StackPointer(), fp, kPointerSize);
-  __ AssertStackConsistency();
-
-  __ Pop(x1, fp, lr);  // Function, Frame, Return address.
-
-  // Load context from the function.
-  __ Ldr(cp, FieldMemOperand(x1, JSFunction::kContextOffset));
-
-  // Get function code.
-  __ Ldr(scratch, FieldMemOperand(x1, JSFunction::kSharedFunctionInfoOffset));
-  __ Ldr(scratch, FieldMemOperand(scratch, SharedFunctionInfo::kCodeOffset));
-  __ Add(scratch, scratch, Code::kHeaderSize - kHeapObjectTag);
-
-  // Re-run JSFunction, x1 is function, cp is context.
-  __ Br(scratch);
-}
-
-
-const bool LiveEdit::kFrameDropperSupported = true;
-
-}  // namespace internal
-}  // namespace v8
-
-#endif  // V8_TARGET_ARCH_ARM64