1 /* Disassembly display.
3 Copyright (C) 1998-2022 Free Software Foundation, Inc.
5 Contributed by Hewlett-Packard Company.
7 This file is part of GDB.
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.
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.
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/>. */
23 #include "arch-utils.h"
25 #include "breakpoint.h"
31 #include "tui/tui-command.h"
32 #include "tui/tui-data.h"
33 #include "tui/tui-win.h"
34 #include "tui/tui-layout.h"
35 #include "tui/tui-winsource.h"
36 #include "tui/tui-stack.h"
37 #include "tui/tui-file.h"
38 #include "tui/tui-disasm.h"
39 #include "tui/tui-source.h"
40 #include "progspace.h"
42 #include "cli/cli-style.h"
43 #include "tui/tui-location.h"
45 #include "gdb_curses.h"
50 std::string addr_string
;
55 /* Helper function to find the number of characters in STR, skipping
56 any ANSI escape sequences. */
58 len_without_escapes (const std::string
&str
)
61 const char *ptr
= str
.c_str ();
64 while ((c
= *ptr
) != '\0')
70 if (style
.parse (ptr
, &n_read
))
74 /* Shouldn't happen, but just skip the ESC if it somehow
88 /* Function to disassemble up to COUNT instructions starting from address
89 PC into the ASM_LINES vector (which will be emptied of any previous
90 contents). Return the address of the COUNT'th instruction after pc.
91 When ADDR_SIZE is non-null then place the maximum size of an address and
92 label into the value pointed to by ADDR_SIZE, and set the addr_size
93 field on each item in ASM_LINES, otherwise the addr_size fields within
94 ASM_LINES are undefined.
96 It is worth noting that ASM_LINES might not have COUNT entries when this
97 function returns. If the disassembly is truncated for some other
98 reason, for example, we hit invalid memory, then ASM_LINES can have
99 fewer entries than requested. */
101 tui_disassemble (struct gdbarch
*gdbarch
,
102 std::vector
<tui_asm_line
> &asm_lines
,
103 CORE_ADDR pc
, int count
,
104 size_t *addr_size
= nullptr)
106 bool term_out
= source_styling
&& gdb_stdout
->can_emit_style_escape ();
107 string_file
gdb_dis_out (term_out
);
109 /* Must start with an empty list. */
112 /* Now construct each line. */
113 for (int i
= 0; i
< count
; ++i
)
116 CORE_ADDR orig_pc
= pc
;
120 pc
= pc
+ gdb_print_insn (gdbarch
, pc
, &gdb_dis_out
, NULL
);
122 catch (const gdb_exception_error
&except
)
124 /* If PC points to an invalid address then we'll catch a
125 MEMORY_ERROR here, this should stop the disassembly, but
126 otherwise is fine. */
127 if (except
.error
!= MEMORY_ERROR
)
132 /* Capture the disassembled instruction. */
133 tal
.insn
= gdb_dis_out
.release ();
135 /* And capture the address the instruction is at. */
137 print_address (gdbarch
, orig_pc
, &gdb_dis_out
);
138 tal
.addr_string
= gdb_dis_out
.release ();
140 if (addr_size
!= nullptr)
145 new_size
= len_without_escapes (tal
.addr_string
);
147 new_size
= tal
.addr_string
.size ();
148 *addr_size
= std::max (*addr_size
, new_size
);
149 tal
.addr_size
= new_size
;
152 asm_lines
.push_back (std::move (tal
));
157 /* Look backward from ADDR for an address from which we can start
158 disassembling, this needs to be something we can be reasonably
159 confident will fall on an instruction boundary. We use msymbol
160 addresses, or the start of a section. */
163 tui_find_backward_disassembly_start_address (CORE_ADDR addr
)
165 struct bound_minimal_symbol msym
, msym_prev
;
167 msym
= lookup_minimal_symbol_by_pc_section (addr
- 1, nullptr,
168 lookup_msym_prefer::TEXT
,
170 if (msym
.minsym
!= nullptr)
171 return BMSYMBOL_VALUE_ADDRESS (msym
);
172 else if (msym_prev
.minsym
!= nullptr)
173 return BMSYMBOL_VALUE_ADDRESS (msym_prev
);
175 /* Find the section that ADDR is in, and look for the start of the
177 struct obj_section
*section
= find_pc_section (addr
);
179 return section
->addr ();
184 /* Find the disassembly address that corresponds to FROM lines above
185 or below the PC. Variable sized instructions are taken into
186 account by the algorithm. */
188 tui_find_disassembly_address (struct gdbarch
*gdbarch
, CORE_ADDR pc
, int from
)
193 max_lines
= (from
> 0) ? from
: - from
;
197 std::vector
<tui_asm_line
> asm_lines
;
202 /* Always disassemble 1 extra instruction here, then if the last
203 instruction fails to disassemble we will take the address of the
204 previous instruction that did disassemble as the result. */
205 tui_disassemble (gdbarch
, asm_lines
, pc
, max_lines
+ 1);
206 new_low
= asm_lines
.back ().addr
;
210 /* In order to disassemble backwards we need to find a suitable
211 address to start disassembling from and then work forward until we
212 re-find the address we're currently at. We can then figure out
213 which address will be at the top of the TUI window after our
214 backward scroll. During our backward disassemble we need to be
215 able to distinguish between the case where the last address we
216 _can_ disassemble is ADDR, and the case where the disassembly
217 just happens to stop at ADDR, for this reason we increase
221 /* When we disassemble a series of instructions this will hold the
222 address of the last instruction disassembled. */
225 /* And this will hold the address of the next instruction that would
226 have been disassembled. */
229 /* As we search backward if we find an address that looks like a
230 promising starting point then we record it in this structure. If
231 the next address we try is not a suitable starting point then we
232 will fall back to the address held here. */
233 gdb::optional
<CORE_ADDR
> possible_new_low
;
235 /* The previous value of NEW_LOW so we know if the new value is
241 /* Find an address from which we can start disassembling. */
243 new_low
= tui_find_backward_disassembly_start_address (new_low
);
245 /* Disassemble forward. */
246 next_addr
= tui_disassemble (gdbarch
, asm_lines
, new_low
, max_lines
);
247 last_addr
= asm_lines
.back ().addr
;
249 /* If disassembling from the current value of NEW_LOW reached PC
250 (or went past it) then this would do as a starting point if we
251 can't find anything better, so remember it. */
252 if (last_addr
>= pc
&& new_low
!= prev_low
253 && asm_lines
.size () >= max_lines
)
254 possible_new_low
.emplace (new_low
);
256 /* Continue searching until we find a value of NEW_LOW from which
257 disassembling MAX_LINES instructions doesn't reach PC. We
258 know this means we can find the required number of previous
259 instructions then. */
261 while ((last_addr
> pc
262 || (last_addr
== pc
&& asm_lines
.size () < max_lines
))
263 && new_low
!= prev_low
);
265 /* If we failed to disassemble the required number of lines then the
266 following walk forward is not going to work, it assumes that
267 ASM_LINES contains exactly MAX_LINES entries. Instead we should
268 consider falling back to a previous possible start address in
270 if (asm_lines
.size () < max_lines
)
272 if (!possible_new_low
.has_value ())
275 /* Take the best possible match we have. */
276 new_low
= *possible_new_low
;
277 next_addr
= tui_disassemble (gdbarch
, asm_lines
, new_low
, max_lines
);
278 last_addr
= asm_lines
.back ().addr
;
279 gdb_assert (asm_lines
.size () >= max_lines
);
282 /* Scan forward disassembling one instruction at a time until
283 the last visible instruction of the window matches the pc.
284 We keep the disassembled instructions in the 'lines' window
285 and shift it downward (increasing its addresses). */
286 int pos
= max_lines
- 1;
291 if (pos
>= max_lines
)
294 CORE_ADDR old_next_addr
= next_addr
;
295 std::vector
<tui_asm_line
> single_asm_line
;
296 next_addr
= tui_disassemble (gdbarch
, single_asm_line
,
298 /* If there are some problems while disassembling exit. */
299 if (next_addr
<= old_next_addr
)
301 gdb_assert (single_asm_line
.size () == 1);
302 asm_lines
[pos
] = single_asm_line
[0];
303 } while (next_addr
<= pc
);
305 if (pos
>= max_lines
)
307 new_low
= asm_lines
[pos
].addr
;
309 /* When scrolling backward the addresses should move backward, or at
310 the very least stay the same if we are at the first address that
311 can be disassembled. */
312 gdb_assert (new_low
<= pc
);
317 /* Function to set the disassembly window's content. */
319 tui_disasm_window::set_contents (struct gdbarch
*arch
,
320 const struct symtab_and_line
&sal
)
325 int tab_len
= tui_tab_width
;
328 CORE_ADDR pc
= sal
.pc
;
333 m_start_line_or_addr
.loa
= LOA_ADDRESS
;
334 m_start_line_or_addr
.u
.addr
= pc
;
335 cur_pc
= tui_location
.addr ();
337 /* Window size, excluding highlight box. */
338 max_lines
= height
- 2;
340 /* Get temporary table that will hold all strings (addr & insn). */
341 std::vector
<tui_asm_line
> asm_lines
;
342 size_t addr_size
= 0;
343 tui_disassemble (m_gdbarch
, asm_lines
, pc
, max_lines
, &addr_size
);
345 /* Align instructions to the same column. */
346 insn_pos
= (1 + (addr_size
/ tab_len
)) * tab_len
;
348 /* Now construct each line. */
349 m_content
.resize (max_lines
);
351 for (i
= 0; i
< max_lines
; i
++)
353 tui_source_element
*src
= &m_content
[i
];
358 if (i
< asm_lines
.size ())
361 = (asm_lines
[i
].addr_string
362 + n_spaces (insn_pos
- asm_lines
[i
].addr_size
)
363 + asm_lines
[i
].insn
);
364 addr
= asm_lines
[i
].addr
;
372 const char *ptr
= line
.c_str ();
374 src
->line
= tui_copy_source_line (&ptr
, &line_len
);
375 m_max_length
= std::max (m_max_length
, line_len
);
377 src
->line_or_addr
.loa
= LOA_ADDRESS
;
378 src
->line_or_addr
.u
.addr
= addr
;
379 src
->is_exec_point
= (addr
== cur_pc
&& line
.size () > 0);
386 tui_get_begin_asm_address (struct gdbarch
**gdbarch_p
, CORE_ADDR
*addr_p
)
388 struct gdbarch
*gdbarch
= get_current_arch ();
391 if (tui_location
.addr () == 0)
393 if (have_full_symbols () || have_partial_symbols ())
395 set_default_source_symtab_and_line ();
396 struct symtab_and_line sal
= get_current_source_symtab_and_line ();
398 if (sal
.symtab
!= nullptr)
399 find_line_pc (sal
.symtab
, sal
.line
, &addr
);
404 struct bound_minimal_symbol main_symbol
405 = lookup_minimal_symbol (main_name (), nullptr, nullptr);
406 if (main_symbol
.minsym
!= nullptr)
407 addr
= BMSYMBOL_VALUE_ADDRESS (main_symbol
);
410 else /* The target is executing. */
412 gdbarch
= tui_location
.gdbarch ();
413 addr
= tui_location
.addr ();
416 *gdbarch_p
= gdbarch
;
420 /* Determine what the low address will be to display in the TUI's
421 disassembly window. This may or may not be the same as the low
424 tui_get_low_disassembly_address (struct gdbarch
*gdbarch
,
425 CORE_ADDR low
, CORE_ADDR pc
)
429 /* Determine where to start the disassembly so that the pc is about
430 in the middle of the viewport. */
431 if (TUI_DISASM_WIN
!= NULL
)
432 pos
= TUI_DISASM_WIN
->height
;
433 else if (TUI_CMD_WIN
== NULL
)
434 pos
= tui_term_height () / 2 - 2;
436 pos
= tui_term_height () - TUI_CMD_WIN
->height
- 2;
439 pc
= tui_find_disassembly_address (gdbarch
, pc
, -pos
);
446 /* Scroll the disassembly forward or backward vertically. */
448 tui_disasm_window::do_scroll_vertical (int num_to_scroll
)
450 if (!m_content
.empty ())
454 pc
= m_start_line_or_addr
.u
.addr
;
456 symtab_and_line sal
{};
457 sal
.pspace
= current_program_space
;
458 sal
.pc
= tui_find_disassembly_address (m_gdbarch
, pc
, num_to_scroll
);
459 update_source_window_as_is (m_gdbarch
, sal
);
464 tui_disasm_window::location_matches_p (struct bp_location
*loc
, int line_no
)
466 return (m_content
[line_no
].line_or_addr
.loa
== LOA_ADDRESS
467 && m_content
[line_no
].line_or_addr
.u
.addr
== loc
->address
);
471 tui_disasm_window::addr_is_displayed (CORE_ADDR addr
) const
473 if (m_content
.size () < SCROLL_THRESHOLD
)
476 for (size_t i
= 0; i
< m_content
.size () - SCROLL_THRESHOLD
; ++i
)
478 if (m_content
[i
].line_or_addr
.loa
== LOA_ADDRESS
479 && m_content
[i
].line_or_addr
.u
.addr
== addr
)
487 tui_disasm_window::maybe_update (struct frame_info
*fi
, symtab_and_line sal
)
491 struct gdbarch
*frame_arch
= get_frame_arch (fi
);
493 if (find_pc_partial_function (sal
.pc
, NULL
, &low
, NULL
) == 0)
495 /* There is no symbol available for current PC. There is no
496 safe way how to "disassemble backwards". */
500 low
= tui_get_low_disassembly_address (frame_arch
, low
, sal
.pc
);
502 struct tui_line_or_address a
;
506 if (!addr_is_displayed (sal
.pc
))
509 update_source_window (frame_arch
, sal
);
514 set_is_exec_point_at (a
);
519 tui_disasm_window::display_start_addr (struct gdbarch
**gdbarch_p
,
522 *gdbarch_p
= m_gdbarch
;
523 *addr_p
= m_start_line_or_addr
.u
.addr
;