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 "qemu/osdep.h"
  21 #include "disas/dis-asm.h"
  22
  23 #include "vixl/a64/disasm-a64.h"
  24
  25 using namespace vixl;
  26
  27 static Decoder *vixl_decoder = NULL;
  28 static Disassembler *vixl_disasm = NULL;
  29
  30 /* We don't use libvixl's PrintDisassembler because its output
  31  * is a little unhelpful (trailing newlines, for example).
  32  * Instead we use our own very similar variant so we have
  33  * control over the format.
  34  */
  35 class QEMUDisassembler : public Disassembler {
  36 public:
  37     QEMUDisassembler() : printf_(NULL), stream_(NULL) { }
  38     ~QEMUDisassembler() { }
  39
  40     void SetStream(FILE *stream) {
  41         stream_ = stream;
  42     }
  43
  44     void SetPrintf(fprintf_function printf_fn) {
  45         printf_ = printf_fn;
  46     }
  47
  48 protected:
  49     virtual void ProcessOutput(const Instruction *instr) {
  50         printf_(stream_, "%08" PRIx32 "      %s",
  51                 instr->InstructionBits(), GetOutput());
  52     }
  53
  54 private:
  55     fprintf_function printf_;
  56     FILE *stream_;
  57 };
  58
  59 static int vixl_is_initialized(void)
  60 {
  61     return vixl_decoder != NULL;
  62 }
  63
  64 static void vixl_init() {
  65     vixl_decoder = new Decoder();
  66     vixl_disasm = new QEMUDisassembler();
  67     vixl_decoder->AppendVisitor(vixl_disasm);
  68 }
  69
  70 #define INSN_SIZE 4
  71
  72 /* Disassemble ARM A64 instruction. This is our only entry
  73  * point from QEMU's C code.
  74  */
  75 int print_insn_arm_a64(uint64_t addr, disassemble_info *info)
  76 {
  77     uint8_t bytes[INSN_SIZE];
  78     uint32_t instrval;
  79     const Instruction *instr;
  80     int status;
  81
  82     status = info->read_memory_func(addr, bytes, INSN_SIZE, info);
  83     if (status != 0) {
  84         info->memory_error_func(status, addr, info);
  85         return -1;
  86     }
  87
  88     if (!vixl_is_initialized()) {
  89         vixl_init();
  90     }
  91
  92     ((QEMUDisassembler *)vixl_disasm)->SetPrintf(info->fprintf_func);
  93     ((QEMUDisassembler *)vixl_disasm)->SetStream(info->stream);
  94
  95     instrval = bytes[0] | bytes[1] << 8 | bytes[2] << 16 | bytes[3] << 24;
  96     instr = reinterpret_cast<const Instruction *>(&instrval);
  97     vixl_disasm->MapCodeAddress(addr, instr);
  98     vixl_decoder->Decode(instr);
  99
 100     return INSN_SIZE;
 101 }