/*
|
* Copyright (C) 2016 The Android Open Source Project
|
*
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
* you may not use this file except in compliance with the License.
|
* You may obtain a copy of the License at
|
*
|
* http://www.apache.org/licenses/LICENSE-2.0
|
*
|
* Unless required by applicable law or agreed to in writing, software
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
* See the License for the specific language governing permissions and
|
* limitations under the License.
|
*/
|
|
#ifndef ART_LIBELFFILE_DWARF_EXPRESSION_H_
|
#define ART_LIBELFFILE_DWARF_EXPRESSION_H_
|
|
#include <cstddef>
|
#include <cstdint>
|
|
#include "dwarf/dwarf_constants.h"
|
#include "dwarf/writer.h"
|
|
namespace art {
|
namespace dwarf {
|
|
// Writer for DWARF expressions which are used in .debug_info and .debug_loc sections.
|
// See the DWARF specification for the precise meaning of the opcodes.
|
// If multiple equivalent encodings are possible, it will choose the most compact one.
|
// The writer is not exhaustive - it only implements opcodes we have needed so far.
|
class Expression : private Writer<> {
|
public:
|
using Writer<>::data;
|
using Writer<>::size;
|
|
// Push signed integer on the stack.
|
void WriteOpConsts(int32_t value) {
|
if (0 <= value && value < 32) {
|
PushUint8(DW_OP_lit0 + value);
|
} else {
|
PushUint8(DW_OP_consts);
|
PushSleb128(value);
|
}
|
}
|
|
// Push unsigned integer on the stack.
|
void WriteOpConstu(uint32_t value) {
|
if (value < 32) {
|
PushUint8(DW_OP_lit0 + value);
|
} else {
|
PushUint8(DW_OP_constu);
|
PushUleb128(value);
|
}
|
}
|
|
// Variable is stored in given register.
|
void WriteOpReg(uint32_t dwarf_reg_num) {
|
if (dwarf_reg_num < 32) {
|
PushUint8(DW_OP_reg0 + dwarf_reg_num);
|
} else {
|
PushUint8(DW_OP_regx);
|
PushUleb128(dwarf_reg_num);
|
}
|
}
|
|
// Variable is stored on stack. Also see DW_AT_frame_base.
|
void WriteOpFbreg(int32_t stack_offset) {
|
PushUint8(DW_OP_fbreg);
|
PushSleb128(stack_offset);
|
}
|
|
// The variable is stored in multiple locations (pieces).
|
void WriteOpPiece(uint32_t num_bytes) {
|
PushUint8(DW_OP_piece);
|
PushUleb128(num_bytes);
|
}
|
|
// Loads 32-bit or 64-bit value depending on architecture.
|
void WriteOpDeref() { PushUint8(DW_OP_deref); }
|
|
// Loads value of given byte size.
|
void WriteOpDerefSize(uint8_t num_bytes) {
|
PushUint8(DW_OP_deref_size);
|
PushUint8(num_bytes);
|
}
|
|
// Pop two values and push their sum.
|
void WriteOpPlus() { PushUint8(DW_OP_plus); }
|
|
// Add constant value to value on top of stack.
|
void WriteOpPlusUconst(uint32_t offset) {
|
PushUint8(DW_OP_plus_uconst);
|
PushUleb128(offset);
|
}
|
|
// Negate top of stack.
|
void WriteOpNeg() { PushUint8(DW_OP_neg); }
|
|
// Pop two values and push their bitwise-AND.
|
void WriteOpAnd() { PushUint8(DW_OP_and); }
|
|
// Push stack base pointer as determined from .debug_frame.
|
void WriteOpCallFrameCfa() { PushUint8(DW_OP_call_frame_cfa); }
|
|
// Push address of the variable we are working with.
|
void WriteOpPushObjectAddress() { PushUint8(DW_OP_push_object_address); }
|
|
// Return the top stack as the value of the variable.
|
// Otherwise, the top of stack is the variable's location.
|
void WriteOpStackValue() { PushUint8(DW_OP_stack_value); }
|
|
explicit Expression(std::vector<uint8_t>* buffer) : Writer<>(buffer) {
|
buffer->clear();
|
}
|
};
|
} // namespace dwarf
|
} // namespace art
|
|
#endif // ART_LIBELFFILE_DWARF_EXPRESSION_H_
|
