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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COURGETTE_DISASSEMBLER_ELF_32_ARM_H_
#define COURGETTE_DISASSEMBLER_ELF_32_ARM_H_
#include <stddef.h>
#include <stdint.h>
#include <map>
#include "base/macros.h"
#include "courgette/disassembler_elf_32.h"
#include "courgette/types_elf.h"
namespace courgette {
class InstructionReceptor;
enum ARM_RVA {
ARM_OFF8,
ARM_OFF11,
ARM_OFF24,
ARM_OFF25,
ARM_OFF21,
};
class DisassemblerElf32ARM : public DisassemblerElf32 {
public:
// Returns true if a valid executable is detected using only quick checks.
static bool QuickDetect(const uint8_t* start, size_t length) {
return DisassemblerElf32::QuickDetect(start, length, EM_ARM);
}
class TypedRVAARM : public TypedRVA {
public:
TypedRVAARM(ARM_RVA type, RVA rva) : TypedRVA(rva), type_(type) { }
~TypedRVAARM() override { }
// TypedRVA interfaces.
CheckBool ComputeRelativeTarget(const uint8_t* op_pointer) override;
CheckBool EmitInstruction(Label* label,
InstructionReceptor* receptor) override;
uint16_t op_size() const override;
uint16_t c_op() const { return c_op_; }
private:
ARM_RVA type_;
uint16_t c_op_; // Set by ComputeRelativeTarget().
const uint8_t* arm_op_;
};
DisassemblerElf32ARM(const uint8_t* start, size_t length);
~DisassemblerElf32ARM() override { }
// DisassemblerElf32 interfaces.
ExecutableType kind() const override { return EXE_ELF_32_ARM; }
e_machine_values ElfEM() const override { return EM_ARM; }
// Takes an ARM or thumb opcode |arm_op| of specified |type| and located at
// |rva|, extracts the instruction-relative target RVA into |*addr| and
// encodes the corresponding Courgette opcode as |*c_op|.
//
// Details on ARM opcodes, and target RVA extraction are taken from
// "ARM Architecture Reference Manual", section A4.1.5 and
// "Thumb-2 supplement", section 4.6.12.
// ARM_OFF24 is for the ARM opcode. The rest are for thumb opcodes.
static CheckBool Compress(ARM_RVA type,
uint32_t arm_op,
RVA rva,
uint16_t* c_op /* out */,
uint32_t* addr /* out */);
// Inverse for Compress(). Takes Courgette op |c_op| and relative address
// |addr| to reconstruct the original ARM or thumb op |*arm_op|.
static CheckBool Decompress(ARM_RVA type,
uint16_t c_op,
uint32_t addr,
uint32_t* arm_op /* out */);
protected:
// DisassemblerElf32 interfaces.
CheckBool RelToRVA(Elf32_Rel rel,
RVA* result) const override WARN_UNUSED_RESULT;
CheckBool ParseRelocationSection(const Elf32_Shdr* section_header,
InstructionReceptor* receptor) const override
WARN_UNUSED_RESULT;
CheckBool ParseRel32RelocsFromSection(const Elf32_Shdr* section)
override WARN_UNUSED_RESULT;
#if COURGETTE_HISTOGRAM_TARGETS
std::map<RVA, int> rel32_target_rvas_;
#endif
private:
DISALLOW_COPY_AND_ASSIGN(DisassemblerElf32ARM);
};
} // namespace courgette
#endif // COURGETTE_DISASSEMBLER_ELF_32_ARM_H_