disas/arm-a64.cc

   1 /*
   2  * ARM A64 disassembly output wrapper to libvixl
   3  * Copyright (c) 2013 Linaro Limited
   4  * Written by Claudio Fontana
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "a64/disasm-a64.h"
  21
  22 extern "C" {
  23 #include "disas/bfd.h"
  24 }
  25
  26 using namespace vixl;
  27
  28 static Decoder *vixl_decoder = NULL;
  29 static Disassembler *vixl_disasm = NULL;
  30
  31 /* We don't use libvixl's PrintDisassembler because its output
  32  * is a little unhelpful (trailing newlines, for example).
  33  * Instead we use our own very similar variant so we have
  34  * control over the format.
  35  */
  36 class QEMUDisassembler : public Disassembler {
  37 public:
  38     QEMUDisassembler() : printf_(NULL), stream_(NULL) { }
  39     ~QEMUDisassembler() { }
  40
  41     void SetStream(FILE *stream) {
  42         stream_ = stream;
  43     }
  44
  45     void SetPrintf(fprintf_function printf_fn) {
  46         printf_ = printf_fn;
  47     }
  48
  49 protected:
  50     virtual void ProcessOutput(const Instruction *instr) {
  51         printf_(stream_, "%08" PRIx32 "      %s",
  52                 instr->InstructionBits(), GetOutput());
  53     }
  54
  55 private:
  56     fprintf_function printf_;
  57     FILE *stream_;
  58 };
  59
  60 static int vixl_is_initialized(void)
  61 {
  62     return vixl_decoder != NULL;
  63 }
  64
  65 static void vixl_init() {
  66     vixl_decoder = new Decoder();
  67     vixl_disasm = new QEMUDisassembler();
  68     vixl_decoder->AppendVisitor(vixl_disasm);
  69 }
  70
  71 #define INSN_SIZE 4
  72
  73 /* Disassemble ARM A64 instruction. This is our only entry
  74  * point from QEMU's C code.
  75  */
  76 int print_insn_arm_a64(uint64_t addr, disassemble_info *info)
  77 {
  78     uint8_t bytes[INSN_SIZE];
  79     uint32_t instrval;
  80     const Instruction *instr;
  81     int status;
  82
  83     status = info->read_memory_func(addr, bytes, INSN_SIZE, info);
  84     if (status != 0) {
  85         info->memory_error_func(status, addr, info);
  86         return -1;
  87     }
  88
  89     if (!vixl_is_initialized()) {
  90         vixl_init();
  91     }
  92
  93     ((QEMUDisassembler *)vixl_disasm)->SetPrintf(info->fprintf_func);
  94     ((QEMUDisassembler *)vixl_disasm)->SetStream(info->stream);
  95
  96     instrval = bytes[0] | bytes[1] << 8 | bytes[2] << 16 | bytes[3] << 24;
  97     instr = reinterpret_cast<const Instruction *>(&instrval);
  98     vixl_disasm->MapCodeAddress(addr, instr);
  99     vixl_decoder->Decode(instr);
 100
 101     return INSN_SIZE;
 102 }