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// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/globals.h"
#if defined(TARGET_ARCH_X64)
#include "vm/debugger.h"
#include "vm/cpu.h"
#include "vm/stub_code.h"
namespace dart {
// TODO(hausner): Handle captured variables.
RawInstance* ActivationFrame::GetLocalVarValue(intptr_t slot_index) {
uword var_address = fp() + slot_index * kWordSize;
return reinterpret_cast<RawInstance*>(
*reinterpret_cast<uword*>(var_address));
}
RawInstance* ActivationFrame::GetInstanceCallReceiver(
intptr_t num_actual_args) {
ASSERT(num_actual_args > 0); // At minimum we have a receiver on the stack.
// Stack pointer points to last argument that was pushed on the stack.
uword receiver_addr = sp() + ((num_actual_args - 1) * kWordSize);
return reinterpret_cast<RawInstance*>(
*reinterpret_cast<uword*>(receiver_addr));
}
void CodeBreakpoint::PatchFunctionReturn() {
uint8_t* code = reinterpret_cast<uint8_t*>(pc_ - 13);
// movq %rbp,%rsp
ASSERT((code[0] == 0x48) && (code[1] == 0x89) && (code[2] == 0xec));
ASSERT(code[3] == 0x5d); // popq %rbp
ASSERT(code[4] == 0xc3); // ret
// Next 8 bytes are nop instructions
ASSERT((code[5] == 0x90) && (code[6] == 0x90) &&
(code[7] == 0x90) && (code[8] == 0x90) &&
(code[9] == 0x90) && (code[10] == 0x90) &&
(code[11] == 0x90) && (code[12] == 0x90));
// Smash code with call instruction and relative target address.
uword stub_addr = StubCode::BreakpointReturnEntryPoint();
code[0] = 0x49;
code[1] = 0xbb;
*reinterpret_cast<uword*>(&code[2]) = stub_addr;
code[10] = 0x41;
code[11] = 0xff;
code[12] = 0xd3;
CPU::FlushICache(pc_ - 13, 13);
}
void CodeBreakpoint::RestoreFunctionReturn() {
uint8_t* code = reinterpret_cast<uint8_t*>(pc_ - 13);
ASSERT((code[0] == 0x49) && (code[1] == 0xbb));
code[0] = 0x48; // movq %rbp,%rsp
code[1] = 0x89;
code[2] = 0xec;
code[3] = 0x5d; // popq %rbp
code[4] = 0xc3; // ret
code[5] = 0x90; // nop
code[6] = 0x90; // nop
code[7] = 0x90; // nop
code[8] = 0x90; // nop
code[9] = 0x90; // nop
code[10] = 0x90; // nop
code[11] = 0x90; // nop
code[12] = 0x90; // nop
CPU::FlushICache(pc_ - 13, 13);
}
} // namespace dart
#endif // defined TARGET_ARCH_X64