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 extern "C" {
  21 #include "qemu/osdep.h"
  22 #include "disas/dis-asm.h"
  23 }
  24
  25 #include "vixl/a64/disasm-a64.h"
  26
  27 using namespace vixl;
  28
  29 static Decoder *vixl_decoder = NULL;
  30 static Disassembler *vixl_disasm = NULL;
  31
  32 /* We don't use libvixl's PrintDisassembler because its output
  33  * is a little unhelpful (trailing newlines, for example).
  34  * Instead we use our own very similar variant so we have
  35  * control over the format.
  36  */
  37 class QEMUDisassembler : public Disassembler {
  38 public:
  39     QEMUDisassembler() : printf_(NULL), stream_(NULL) { }
  40     ~QEMUDisassembler() { }
  41
  42     void SetStream(FILE *stream) {
  43         stream_ = stream;
  44     }
  45
  46     void SetPrintf(fprintf_function printf_fn) {
  47         printf_ = printf_fn;
  48     }
  49
  50 protected:
  51     virtual void ProcessOutput(const Instruction *instr) {
  52         printf_(stream_, "%08" PRIx32 "      %s",
  53                 instr->InstructionBits(), GetOutput());
  54     }
  55
  56 private:
  57     fprintf_function printf_;
  58     FILE *stream_;
  59 };
  60
  61 static int vixl_is_initialized(void)
  62 {
  63     return vixl_decoder != NULL;
  64 }
  65
  66 static void vixl_init() {
  67     vixl_decoder = new Decoder();
  68     vixl_disasm = new QEMUDisassembler();
  69     vixl_decoder->AppendVisitor(vixl_disasm);
  70 }
  71
  72 #define INSN_SIZE 4
  73
  74 /* Disassemble ARM A64 instruction. This is our only entry
  75  * point from QEMU's C code.
  76  */
  77 int print_insn_arm_a64(uint64_t addr, disassemble_info *info)
  78 {
  79     uint8_t bytes[INSN_SIZE];
  80     uint32_t instrval;
  81     const Instruction *instr;
  82     int status;
  83
  84     status = info->read_memory_func(addr, bytes, INSN_SIZE, info);
  85     if (status != 0) {
  86         info->memory_error_func(status, addr, info);
  87         return -1;
  88     }
  89
  90     if (!vixl_is_initialized()) {
  91         vixl_init();
  92     }
  93
  94     ((QEMUDisassembler *)vixl_disasm)->SetPrintf(info->fprintf_func);
  95     ((QEMUDisassembler *)vixl_disasm)->SetStream(info->stream);
  96
  97     instrval = bytes[0] | bytes[1] << 8 | bytes[2] << 16 | bytes[3] << 24;
  98     instr = reinterpret_cast<const Instruction *>(&instrval);
  99     vixl_disasm->MapCodeAddress(addr, instr);
 100     vixl_decoder->Decode(instr);
 101
 102     return INSN_SIZE;
 103 }