gdb/tui/tui-disasm.c

   1 /* Disassembly display.
   2
   3    Copyright (C) 1998-2019 Free Software Foundation, Inc.
   4
   5    Contributed by Hewlett-Packard Company.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "arch-utils.h"
  24 #include "symtab.h"
  25 #include "breakpoint.h"
  26 #include "frame.h"
  27 #include "value.h"
  28 #include "source.h"
  29 #include "disasm.h"
  30 #include "tui/tui.h"
  31 #include "tui/tui-data.h"
  32 #include "tui/tui-win.h"
  33 #include "tui/tui-layout.h"
  34 #include "tui/tui-winsource.h"
  35 #include "tui/tui-stack.h"
  36 #include "tui/tui-file.h"
  37 #include "tui/tui-disasm.h"
  38 #include "tui/tui-source.h"
  39 #include "progspace.h"
  40 #include "objfiles.h"
  41
  42 #include "gdb_curses.h"
  43
  44 struct tui_asm_line
  45 {
  46   CORE_ADDR addr;
  47   char *addr_string;
  48   char *insn;
  49 };
  50
  51 /* Function to set the disassembly window's content.
  52    Disassemble count lines starting at pc.
  53    Return address of the count'th instruction after pc.  */
  54 static CORE_ADDR
  55 tui_disassemble (struct gdbarch *gdbarch, struct tui_asm_line *asm_lines,
  56                  CORE_ADDR pc, int count)
  57 {
  58   string_file gdb_dis_out;
  59
  60   /* Now construct each line.  */
  61   for (; count > 0; count--, asm_lines++)
  62     {
  63       xfree (asm_lines->addr_string);
  64       xfree (asm_lines->insn);
  65
  66       print_address (gdbarch, pc, &gdb_dis_out);
  67       asm_lines->addr = pc;
  68       asm_lines->addr_string = xstrdup (gdb_dis_out.c_str ());
  69
  70       gdb_dis_out.clear ();
  71
  72       pc = pc + gdb_print_insn (gdbarch, pc, &gdb_dis_out, NULL);
  73
  74       asm_lines->insn = xstrdup (gdb_dis_out.c_str ());
  75
  76       /* Reset the buffer to empty.  */
  77       gdb_dis_out.clear ();
  78     }
  79   return pc;
  80 }
  81
  82 /* Find the disassembly address that corresponds to FROM lines above
  83    or below the PC.  Variable sized instructions are taken into
  84    account by the algorithm.  */
  85 static CORE_ADDR
  86 tui_find_disassembly_address (struct gdbarch *gdbarch, CORE_ADDR pc, int from)
  87 {
  88   CORE_ADDR new_low;
  89   int max_lines;
  90   int i;
  91   struct tui_asm_line *asm_lines;
  92
  93   max_lines = (from > 0) ? from : - from;
  94   if (max_lines <= 1)
  95      return pc;
  96
  97   asm_lines = XALLOCAVEC (struct tui_asm_line, max_lines);
  98   memset (asm_lines, 0, sizeof (struct tui_asm_line) * max_lines);
  99
 100   new_low = pc;
 101   if (from > 0)
 102     {
 103       tui_disassemble (gdbarch, asm_lines, pc, max_lines);
 104       new_low = asm_lines[max_lines - 1].addr;
 105     }
 106   else
 107     {
 108       CORE_ADDR last_addr;
 109       int pos;
 110       struct bound_minimal_symbol msymbol;
 111
 112       /* Find backward an address which is a symbol and for which
 113          disassembling from that address will fill completely the
 114          window.  */
 115       pos = max_lines - 1;
 116       do {
 117          new_low -= 1 * max_lines;
 118          msymbol = lookup_minimal_symbol_by_pc_section (new_low, 0);
 119
 120          if (msymbol.minsym)
 121             new_low = BMSYMBOL_VALUE_ADDRESS (msymbol);
 122          else
 123             new_low += 1 * max_lines;
 124
 125          tui_disassemble (gdbarch, asm_lines, new_low, max_lines);
 126          last_addr = asm_lines[pos].addr;
 127       } while (last_addr > pc && msymbol.minsym);
 128
 129       /* Scan forward disassembling one instruction at a time until
 130          the last visible instruction of the window matches the pc.
 131          We keep the disassembled instructions in the 'lines' window
 132          and shift it downward (increasing its addresses).  */
 133       if (last_addr < pc)
 134         do
 135           {
 136             CORE_ADDR next_addr;
 137
 138             pos++;
 139             if (pos >= max_lines)
 140               pos = 0;
 141
 142             next_addr = tui_disassemble (gdbarch, &asm_lines[pos],
 143                                          last_addr, 1);
 144
 145             /* If there are some problems while disassembling exit.  */
 146             if (next_addr <= last_addr)
 147               break;
 148             last_addr = next_addr;
 149           } while (last_addr <= pc);
 150       pos++;
 151       if (pos >= max_lines)
 152          pos = 0;
 153       new_low = asm_lines[pos].addr;
 154     }
 155   for (i = 0; i < max_lines; i++)
 156     {
 157       xfree (asm_lines[i].addr_string);
 158       xfree (asm_lines[i].insn);
 159     }
 160   return new_low;
 161 }
 162
 163 /* Function to set the disassembly window's content.  */
 164 enum tui_status
 165 tui_set_disassem_content (tui_source_window_base *win_info,
 166                           struct gdbarch *gdbarch, CORE_ADDR pc)
 167 {
 168   int i;
 169   int offset = win_info->horizontal_offset;
 170   int max_lines, line_width;
 171   CORE_ADDR cur_pc;
 172   struct tui_locator_window *locator = tui_locator_win_info_ptr ();
 173   int tab_len = tui_tab_width;
 174   struct tui_asm_line *asm_lines;
 175   int insn_pos;
 176   int addr_size, insn_size;
 177   char *line;
 178
 179   if (pc == 0)
 180     return TUI_FAILURE;
 181
 182   win_info->gdbarch = gdbarch;
 183   win_info->start_line_or_addr.loa = LOA_ADDRESS;
 184   win_info->start_line_or_addr.u.addr = pc;
 185   cur_pc = locator->addr;
 186
 187   /* Window size, excluding highlight box.  */
 188   max_lines = win_info->height - 2;
 189   line_width = win_info->width - 2;
 190
 191   /* Get temporary table that will hold all strings (addr & insn).  */
 192   asm_lines = XALLOCAVEC (struct tui_asm_line, max_lines);
 193   memset (asm_lines, 0, sizeof (struct tui_asm_line) * max_lines);
 194
 195   tui_disassemble (gdbarch, asm_lines, pc, max_lines);
 196
 197   /* Determine maximum address- and instruction lengths.  */
 198   addr_size = 0;
 199   insn_size = 0;
 200   for (i = 0; i < max_lines; i++)
 201     {
 202       size_t len = strlen (asm_lines[i].addr_string);
 203
 204       if (len > addr_size)
 205         addr_size = len;
 206
 207       len = strlen (asm_lines[i].insn);
 208       if (len > insn_size)
 209         insn_size = len;
 210     }
 211
 212   /* Align instructions to the same column.  */
 213   insn_pos = (1 + (addr_size / tab_len)) * tab_len;
 214
 215   /* Allocate memory to create each line.  */
 216   line = (char*) alloca (insn_pos + insn_size + 1);
 217
 218   /* Now construct each line.  */
 219   win_info->content.resize (max_lines);
 220   for (i = 0; i < max_lines; i++)
 221     {
 222       int cur_len;
 223
 224       tui_source_element *src = &win_info->content[i];
 225       strcpy (line, asm_lines[i].addr_string);
 226       cur_len = strlen (line);
 227       memset (line + cur_len, ' ', insn_pos - cur_len);
 228       strcpy (line + insn_pos, asm_lines[i].insn);
 229
 230       /* Now copy the line taking the offset into account.  */
 231       xfree (src->line);
 232       if (strlen (line) > offset)
 233         src->line = xstrndup (&line[offset], line_width);
 234       else
 235         src->line = xstrdup ("");
 236
 237       src->line_or_addr.loa = LOA_ADDRESS;
 238       src->line_or_addr.u.addr = asm_lines[i].addr;
 239       src->is_exec_point = asm_lines[i].addr == cur_pc;
 240
 241       xfree (asm_lines[i].addr_string);
 242       xfree (asm_lines[i].insn);
 243     }
 244   return TUI_SUCCESS;
 245 }
 246
 247
 248 /* Function to display the disassembly window with disassembled code.  */
 249 void
 250 tui_show_disassem (struct gdbarch *gdbarch, CORE_ADDR start_addr)
 251 {
 252   struct symtab *s = find_pc_line_symtab (start_addr);
 253   struct tui_win_info *win_with_focus = tui_win_with_focus ();
 254   struct tui_line_or_address val;
 255
 256   gdb_assert (TUI_DISASM_WIN != nullptr && TUI_DISASM_WIN->is_visible ());
 257
 258   val.loa = LOA_ADDRESS;
 259   val.u.addr = start_addr;
 260   tui_update_source_window (TUI_DISASM_WIN, gdbarch, s, val);
 261
 262   /* If the focus was in the src win, put it in the asm win, if the
 263      source view isn't split.  */
 264   if (tui_current_layout () != SRC_DISASSEM_COMMAND
 265       && win_with_focus == TUI_SRC_WIN)
 266     tui_set_win_focus_to (TUI_DISASM_WIN);
 267 }
 268
 269
 270 /* Function to display the disassembly window.  */
 271 void
 272 tui_show_disassem_and_update_source (struct gdbarch *gdbarch,
 273                                      CORE_ADDR start_addr)
 274 {
 275   struct symtab_and_line sal;
 276
 277   tui_show_disassem (gdbarch, start_addr);
 278   if (tui_current_layout () == SRC_DISASSEM_COMMAND)
 279     {
 280       struct tui_line_or_address val;
 281
 282       /* Update what is in the source window if it is displayed too,
 283          note that it follows what is in the disassembly window and
 284          visa-versa.  */
 285       sal = find_pc_line (start_addr, 0);
 286       val.loa = LOA_LINE;
 287       val.u.line_no = sal.line;
 288       tui_update_source_window (TUI_SRC_WIN, gdbarch, sal.symtab, val);
 289       if (sal.symtab)
 290         {
 291           set_current_source_symtab_and_line (sal);
 292           tui_update_locator_fullname (symtab_to_fullname (sal.symtab));
 293         }
 294       else
 295         tui_update_locator_fullname ("?");
 296     }
 297 }
 298
 299 void
 300 tui_get_begin_asm_address (struct gdbarch **gdbarch_p, CORE_ADDR *addr_p)
 301 {
 302   struct tui_locator_window *locator;
 303   struct gdbarch *gdbarch = get_current_arch ();
 304   CORE_ADDR addr;
 305
 306   locator = tui_locator_win_info_ptr ();
 307
 308   if (locator->addr == 0)
 309     {
 310       struct bound_minimal_symbol main_symbol;
 311
 312       /* Find address of the start of program.
 313          Note: this should be language specific.  */
 314       main_symbol = lookup_minimal_symbol ("main", NULL, NULL);
 315       if (main_symbol.minsym == 0)
 316         main_symbol = lookup_minimal_symbol ("MAIN", NULL, NULL);
 317       if (main_symbol.minsym == 0)
 318         main_symbol = lookup_minimal_symbol ("_start", NULL, NULL);
 319       if (main_symbol.minsym)
 320         addr = BMSYMBOL_VALUE_ADDRESS (main_symbol);
 321       else
 322         addr = 0;
 323     }
 324   else                          /* The target is executing.  */
 325     {
 326       gdbarch = locator->gdbarch;
 327       addr = locator->addr;
 328     }
 329
 330   *gdbarch_p = gdbarch;
 331   *addr_p = addr;
 332 }
 333
 334 /* Determine what the low address will be to display in the TUI's
 335    disassembly window.  This may or may not be the same as the low
 336    address input.  */
 337 CORE_ADDR
 338 tui_get_low_disassembly_address (struct gdbarch *gdbarch,
 339                                  CORE_ADDR low, CORE_ADDR pc)
 340 {
 341   int pos;
 342
 343   /* Determine where to start the disassembly so that the pc is about
 344      in the middle of the viewport.  */
 345   pos = tui_default_win_viewport_height (DISASSEM_WIN, DISASSEM_COMMAND) / 2;
 346   pc = tui_find_disassembly_address (gdbarch, pc, -pos);
 347
 348   if (pc < low)
 349     pc = low;
 350   return pc;
 351 }
 352
 353 /* Scroll the disassembly forward or backward vertically.  */
 354 void
 355 tui_disasm_window::do_scroll_vertical (int num_to_scroll)
 356 {
 357   if (!content.empty ())
 358     {
 359       CORE_ADDR pc;
 360       struct tui_line_or_address val;
 361
 362       pc = content[0].line_or_addr.u.addr;
 363       if (num_to_scroll >= 0)
 364         num_to_scroll++;
 365       else
 366         --num_to_scroll;
 367
 368       val.loa = LOA_ADDRESS;
 369       val.u.addr = tui_find_disassembly_address (gdbarch, pc, num_to_scroll);
 370       update_source_window_as_is (gdbarch, NULL, val);
 371     }
 372 }
 373
 374 bool
 375 tui_disasm_window::location_matches_p (struct bp_location *loc, int line_no)
 376 {
 377   return (content[line_no].line_or_addr.loa == LOA_ADDRESS
 378           && content[line_no].line_or_addr.u.addr == loc->address);
 379 }
 380
 381 bool
 382 tui_disasm_window::addr_is_displayed (CORE_ADDR addr) const
 383 {
 384   bool is_displayed = false;
 385   int threshold = SCROLL_THRESHOLD;
 386
 387   int i = 0;
 388   while (i < content.size () - threshold && !is_displayed)
 389     {
 390       is_displayed
 391         = (content[i].line_or_addr.loa == LOA_ADDRESS
 392            && content[i].line_or_addr.u.addr == addr);
 393       i++;
 394     }
 395
 396   return is_displayed;
 397 }
 398
 399 void
 400 tui_disasm_window::maybe_update (struct frame_info *fi, symtab_and_line sal,
 401                                  int line_no, CORE_ADDR addr)
 402 {
 403   CORE_ADDR low;
 404
 405   if (find_pc_partial_function (get_frame_pc (fi),
 406                                 NULL, &low, NULL) == 0)
 407     {
 408       /* There is no symbol available for current PC.  There is no
 409          safe way how to "disassemble backwards".  */
 410       low = get_frame_pc (fi);
 411     }
 412   else
 413     low = tui_get_low_disassembly_address (get_frame_arch (fi),
 414                                            low, get_frame_pc (fi));
 415
 416   struct tui_line_or_address a;
 417
 418   a.loa = LOA_ADDRESS;
 419   a.u.addr = low;
 420   if (!addr_is_displayed (addr))
 421     tui_update_source_window (this, get_frame_arch (fi),
 422                               sal.symtab, a);
 423   else
 424     {
 425       a.u.addr = addr;
 426       set_is_exec_point_at (a);
 427     }
 428 }