gdb/disasm-selftests.c

   1 /* Self tests for disassembler for GDB, the GNU debugger.
   2
   3    Copyright (C) 2017-2024 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "disasm.h"
  21 #include "gdbsupport/selftest.h"
  22 #include "selftest-arch.h"
  23 #include "gdbarch.h"
  24
  25 namespace selftests {
  26
  27 /* Return a pointer to a buffer containing an instruction that can be
  28    disassembled for architecture GDBARCH.  *LEN will be set to the length
  29    of the returned buffer.
  30
  31    If there's no known instruction to disassemble for GDBARCH (because we
  32    haven't figured on out, not because no instructions exist) then nullptr
  33    is returned, and *LEN is set to 0.  */
  34
  35 static const gdb_byte *
  36 get_test_insn (struct gdbarch *gdbarch, size_t *len)
  37 {
  38   *len = 0;
  39   const gdb_byte *insn = nullptr;
  40
  41   switch (gdbarch_bfd_arch_info (gdbarch)->arch)
  42     {
  43     case bfd_arch_bfin:
  44       /* M3.L = 0xe117 */
  45       static const gdb_byte bfin_insn[] = {0x17, 0xe1, 0xff, 0xff};
  46
  47       insn = bfin_insn;
  48       *len = sizeof (bfin_insn);
  49       break;
  50     case bfd_arch_arm:
  51       /* mov     r0, #0 */
  52       static const gdb_byte arm_insn[] = {0x0, 0x0, 0xa0, 0xe3};
  53
  54       insn = arm_insn;
  55       *len = sizeof (arm_insn);
  56       break;
  57     case bfd_arch_ia64:
  58       /* We get:
  59          internal-error: gdbarch_sw_breakpoint_from_kind:
  60          Assertion `gdbarch->sw_breakpoint_from_kind != NULL' failed.  */
  61       return insn;
  62     case bfd_arch_mep:
  63       /* Disassembles as '*unknown*' insn, then len self-check fails.  */
  64       return insn;
  65     case bfd_arch_mips:
  66       if (gdbarch_bfd_arch_info (gdbarch)->mach == bfd_mach_mips16)
  67         /* Disassembles insn, but len self-check fails.  */
  68         return insn;
  69       goto generic_case;
  70     case bfd_arch_tic6x:
  71       /* Disassembles as '<undefined instruction 0x56454314>' insn, but len
  72          self-check passes, so let's allow it.  */
  73       goto generic_case;
  74     case bfd_arch_xtensa:
  75       /* Disassembles insn, but len self-check fails.  */
  76       return insn;
  77     case bfd_arch_or1k:
  78       /* Disassembles as '*unknown*' insn, but len self-check passes, so let's
  79          allow it.  */
  80       goto generic_case;
  81     case bfd_arch_s390:
  82       /* nopr %r7 */
  83       static const gdb_byte s390_insn[] = {0x07, 0x07};
  84
  85       insn = s390_insn;
  86       *len = sizeof (s390_insn);
  87       break;
  88     case bfd_arch_xstormy16:
  89       /* nop */
  90       static const gdb_byte xstormy16_insn[] = {0x0, 0x0};
  91
  92       insn = xstormy16_insn;
  93       *len = sizeof (xstormy16_insn);
  94       break;
  95     case bfd_arch_nios2:
  96     case bfd_arch_score:
  97     case bfd_arch_riscv:
  98       /* nios2, riscv, and score need to know the current instruction
  99          to select breakpoint instruction.  Give the breakpoint
 100          instruction kind explicitly.  */
 101       {
 102         int bplen;
 103         insn = gdbarch_sw_breakpoint_from_kind (gdbarch, 4, &bplen);
 104         *len = bplen;
 105       }
 106       break;
 107     case bfd_arch_arc:
 108       /* PR 21003 */
 109       if (gdbarch_bfd_arch_info (gdbarch)->mach == bfd_mach_arc_arc601)
 110         return insn;
 111       goto generic_case;
 112     case bfd_arch_z80:
 113       {
 114         int bplen;
 115         insn = gdbarch_sw_breakpoint_from_kind (gdbarch, 0x0008, &bplen);
 116         *len = bplen;
 117       }
 118       break;
 119     case bfd_arch_i386:
 120       {
 121         const struct bfd_arch_info *info = gdbarch_bfd_arch_info (gdbarch);
 122         /* The disassembly tests will fail on x86-linux because
 123            opcodes rejects an attempt to disassemble for an arch with
 124            a 64-bit address size when bfd_vma is 32-bit.  */
 125         if (info->bits_per_address > sizeof (bfd_vma) * CHAR_BIT)
 126           return insn;
 127       }
 128       [[fallthrough]];
 129     default:
 130     generic_case:
 131       {
 132         /* Test disassemble breakpoint instruction.  */
 133         CORE_ADDR pc = 0;
 134         int kind;
 135         int bplen;
 136
 137         struct gdbarch_info info;
 138         info.bfd_arch_info = gdbarch_bfd_arch_info (gdbarch);
 139
 140         enum gdb_osabi it;
 141         bool found = false;
 142         for (it = GDB_OSABI_UNKNOWN; it != GDB_OSABI_INVALID;
 143              it = static_cast<enum gdb_osabi>(static_cast<int>(it) + 1))
 144           {
 145             if (it == GDB_OSABI_UNKNOWN)
 146               continue;
 147
 148             info.osabi = it;
 149
 150             if (it != GDB_OSABI_NONE)
 151               {
 152                 if (!has_gdb_osabi_handler (info))
 153                   /* Unsupported.  Skip to prevent warnings like:
 154                      A handler for the OS ABI <x> is not built into this
 155                      configuration of GDB.  Attempting to continue with the
 156                      default <y> settings.  */
 157                   continue;
 158               }
 159
 160             gdbarch = gdbarch_find_by_info (info);
 161             SELF_CHECK (gdbarch != NULL);
 162
 163             try
 164               {
 165                 kind = gdbarch_breakpoint_kind_from_pc (gdbarch, &pc);
 166                 insn = gdbarch_sw_breakpoint_from_kind (gdbarch, kind, &bplen);
 167               }
 168             catch (const gdb_exception_error &)
 169               {
 170                 continue;
 171               }
 172             found = true;
 173             break;
 174           }
 175
 176         /* Assert that we have found an instruction to disassemble.  */
 177         SELF_CHECK (found);
 178
 179         *len = bplen;
 180         break;
 181       }
 182     }
 183   SELF_CHECK (*len > 0);
 184
 185   return insn;
 186 }
 187
 188 /* Test disassembly of one instruction.  */
 189
 190 static void
 191 print_one_insn_test (struct gdbarch *gdbarch)
 192 {
 193   size_t len;
 194   const gdb_byte *insn = get_test_insn (gdbarch, &len);
 195
 196   if (insn == nullptr)
 197     return;
 198
 199   /* Test gdb_disassembler for a given gdbarch by reading data from a
 200      pre-allocated buffer.  If you want to see the disassembled
 201      instruction printed to gdb_stdout, use maint selftest -verbose.  */
 202
 203   class gdb_disassembler_test : public gdb_disassembler
 204   {
 205   public:
 206
 207     explicit gdb_disassembler_test (struct gdbarch *gdbarch,
 208                                     const gdb_byte *insn,
 209                                     size_t len)
 210       : gdb_disassembler (gdbarch,
 211                           (run_verbose () ? gdb_stdlog : &null_stream),
 212                           gdb_disassembler_test::read_memory),
 213         m_insn (insn), m_len (len)
 214     {
 215     }
 216
 217     int
 218     print_insn (CORE_ADDR memaddr)
 219     {
 220       int len = gdb_disassembler::print_insn (memaddr);
 221
 222       if (run_verbose ())
 223         debug_printf ("\n");
 224
 225       return len;
 226     }
 227
 228   private:
 229     /* A buffer contain one instruction.  */
 230     const gdb_byte *m_insn;
 231
 232     /* Length of the buffer.  */
 233     size_t m_len;
 234
 235     static int read_memory (bfd_vma memaddr, gdb_byte *myaddr,
 236                             unsigned int len,
 237                             struct disassemble_info *info) noexcept
 238     {
 239       gdb_disassembler_test *self
 240         = static_cast<gdb_disassembler_test *>(info->application_data);
 241
 242       /* The disassembler in opcodes may read more data than one
 243          instruction.  Supply infinite consecutive copies
 244          of the same instruction.  */
 245       for (size_t i = 0; i < len; i++)
 246         myaddr[i] = self->m_insn[(memaddr + i) % self->m_len];
 247
 248       return 0;
 249     }
 250   };
 251
 252   gdb_disassembler_test di (gdbarch, insn, len);
 253
 254   SELF_CHECK (di.print_insn (0) == len);
 255 }
 256
 257 /* Test the gdb_buffered_insn_length function.  */
 258
 259 static void
 260 buffered_insn_length_test (struct gdbarch *gdbarch)
 261 {
 262   size_t buf_len;
 263   const gdb_byte *insn = get_test_insn (gdbarch, &buf_len);
 264
 265   if (insn == nullptr)
 266     return;
 267
 268   /* The tic6x architecture is VLIW.  Disassembling requires that the
 269      entire instruction bundle be available.  However, the buffer we got
 270      back from get_test_insn only contains a single instruction, which is
 271      just part of an instruction bundle.  As a result, the disassemble will
 272      fail.  To avoid this, skip tic6x tests now.  */
 273   if (gdbarch_bfd_arch_info (gdbarch)->arch == bfd_arch_tic6x)
 274     return;
 275
 276   CORE_ADDR insn_address = 0;
 277   int calculated_len = gdb_buffered_insn_length (gdbarch, insn, buf_len,
 278                                                  insn_address);
 279
 280   SELF_CHECK (calculated_len == buf_len);
 281 }
 282
 283 /* Test disassembly on memory error.  */
 284
 285 static void
 286 memory_error_test (struct gdbarch *gdbarch)
 287 {
 288   class gdb_disassembler_test : public gdb_disassembler
 289   {
 290   public:
 291     gdb_disassembler_test (struct gdbarch *gdbarch)
 292       : gdb_disassembler (gdbarch, &null_stream,
 293                           gdb_disassembler_test::read_memory)
 294     {
 295     }
 296
 297     static int read_memory (bfd_vma memaddr, gdb_byte *myaddr,
 298                             unsigned int len,
 299                             struct disassemble_info *info) noexcept
 300     {
 301       /* Always return an error.  */
 302       return -1;
 303     }
 304   };
 305
 306   if (gdbarch_bfd_arch_info (gdbarch)->arch == bfd_arch_i386)
 307     {
 308       const struct bfd_arch_info *info = gdbarch_bfd_arch_info (gdbarch);
 309       /* This test will fail on x86-linux because opcodes rejects an
 310          attempt to disassemble for an arch with a 64-bit address size
 311          when bfd_vma is 32-bit.  */
 312       if (info->bits_per_address > sizeof (bfd_vma) * CHAR_BIT)
 313         return;
 314     }
 315
 316   gdb_disassembler_test di (gdbarch);
 317   bool saw_memory_error = false;
 318
 319   try
 320     {
 321       di.print_insn (0);
 322     }
 323   catch (const gdb_exception_error &ex)
 324     {
 325       if (ex.error == MEMORY_ERROR)
 326         saw_memory_error = true;
 327     }
 328
 329   /* Expect MEMORY_ERROR.  */
 330   SELF_CHECK (saw_memory_error);
 331 }
 332
 333 } // namespace selftests
 334
 335 void _initialize_disasm_selftests ();
 336 void
 337 _initialize_disasm_selftests ()
 338 {
 339   selftests::register_test_foreach_arch ("print_one_insn",
 340                                          selftests::print_one_insn_test);
 341   selftests::register_test_foreach_arch ("memory_error",
 342                                          selftests::memory_error_test);
 343   selftests::register_test_foreach_arch ("buffered_insn_length",
 344                                          selftests::buffered_insn_length_test);
 345 }