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/tmp/gdb-7.10/gdb/inline-frame.c
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1 /* Inline frame unwinder for GDB.
2 
3  Copyright (C) 2008-2015 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 "defs.h"
21 #include "inline-frame.h"
22 #include "addrmap.h"
23 #include "block.h"
24 #include "frame-unwind.h"
25 #include "inferior.h"
26 #include "regcache.h"
27 #include "symtab.h"
28 #include "vec.h"
29 #include "frame.h"
30 
31 /* We need to save a few variables for every thread stopped at the
32  virtual call site of an inlined function. If there was always a
33  "struct thread_info", we could hang it off that; in the mean time,
34  keep our own list. */
36 {
37  /* The thread this data relates to. It should be a currently
38  stopped thread; we assume thread IDs never change while the
39  thread is stopped. */
41 
42  /* The number of inlined functions we are skipping. Each of these
43  functions can be stepped in to. */
45 
46  /* Only valid if SKIPPED_FRAMES is non-zero. This is the PC used
47  when calculating SKIPPED_FRAMES; used to check whether we have
48  moved to a new location by user request. If so, we invalidate
49  any skipped frames. */
51 
52  /* Only valid if SKIPPED_FRAMES is non-zero. This is the symbol
53  of the outermost skipped inline function. It's used to find the
54  call site of the current frame. */
56 };
57 
60 
61 static VEC(inline_state_s) *inline_states;
62 
63 /* Locate saved inlined frame state for PTID, if it exists
64  and is valid. */
65 
66 static struct inline_state *
67 find_inline_frame_state (ptid_t ptid)
68 {
69  struct inline_state *state;
70  int ix;
71 
72  for (ix = 0; VEC_iterate (inline_state_s, inline_states, ix, state); ix++)
73  {
74  if (ptid_equal (state->ptid, ptid))
75  {
76  struct regcache *regcache = get_thread_regcache (ptid);
77  CORE_ADDR current_pc = regcache_read_pc (regcache);
78 
79  if (current_pc != state->saved_pc)
80  {
81  /* PC has changed - this context is invalid. Use the
82  default behavior. */
83  VEC_unordered_remove (inline_state_s, inline_states, ix);
84  return NULL;
85  }
86  else
87  return state;
88  }
89  }
90 
91  return NULL;
92 }
93 
94 /* Allocate saved inlined frame state for PTID. */
95 
96 static struct inline_state *
98 {
99  struct inline_state *state;
100 
101  state = VEC_safe_push (inline_state_s, inline_states, NULL);
102  memset (state, 0, sizeof (*state));
103  state->ptid = ptid;
104 
105  return state;
106 }
107 
108 /* Forget about any hidden inlined functions in PTID, which is new or
109  about to be resumed. PTID may be minus_one_ptid (all processes)
110  or a PID (all threads in this process). */
111 
112 void
114 {
115  struct inline_state *state;
116  int ix;
117 
118  if (ptid_equal (ptid, minus_one_ptid))
119  {
120  VEC_free (inline_state_s, inline_states);
121  return;
122  }
123 
124  if (ptid_is_pid (ptid))
125  {
126  VEC (inline_state_s) *new_states = NULL;
127  int pid = ptid_get_pid (ptid);
128 
129  for (ix = 0;
130  VEC_iterate (inline_state_s, inline_states, ix, state);
131  ix++)
132  if (pid != ptid_get_pid (state->ptid))
133  VEC_safe_push (inline_state_s, new_states, state);
134  VEC_free (inline_state_s, inline_states);
135  inline_states = new_states;
136  return;
137  }
138 
139  for (ix = 0; VEC_iterate (inline_state_s, inline_states, ix, state); ix++)
140  if (ptid_equal (state->ptid, ptid))
141  {
142  VEC_unordered_remove (inline_state_s, inline_states, ix);
143  return;
144  }
145 }
146 
147 static void
148 inline_frame_this_id (struct frame_info *this_frame,
149  void **this_cache,
150  struct frame_id *this_id)
151 {
152  struct symbol *func;
153 
154  /* In order to have a stable frame ID for a given inline function,
155  we must get the stack / special addresses from the underlying
156  real frame's this_id method. So we must call
157  get_prev_frame_always. Because we are inlined into some
158  function, there must be previous frames, so this is safe - as
159  long as we're careful not to create any cycles. */
160  *this_id = get_frame_id (get_prev_frame_always (this_frame));
161 
162  /* We need a valid frame ID, so we need to be based on a valid
163  frame. FSF submission NOTE: this would be a good assertion to
164  apply to all frames, all the time. That would fix the ambiguity
165  of null_frame_id (between "no/any frame" and "the outermost
166  frame"). This will take work. */
167  gdb_assert (frame_id_p (*this_id));
168 
169  /* For now, require we don't match outer_frame_id either (see
170  comment above). */
171  gdb_assert (!frame_id_eq (*this_id, outer_frame_id));
172 
173  /* Future work NOTE: Alexandre Oliva applied a patch to GCC 4.3
174  which generates DW_AT_entry_pc for inlined functions when
175  possible. If this attribute is available, we should use it
176  in the frame ID (and eventually, to set breakpoints). */
177  func = get_frame_function (this_frame);
178  gdb_assert (func != NULL);
179  (*this_id).code_addr = BLOCK_START (SYMBOL_BLOCK_VALUE (func));
180  (*this_id).artificial_depth++;
181 }
182 
183 static struct value *
184 inline_frame_prev_register (struct frame_info *this_frame, void **this_cache,
185  int regnum)
186 {
187  /* Use get_frame_register_value instead of
188  frame_unwind_got_register, to avoid requiring this frame's ID.
189  This frame's ID depends on the previous frame's ID (unusual), and
190  the previous frame's ID depends on this frame's unwound
191  registers. If unwinding registers from this frame called
192  get_frame_id, there would be a loop.
193 
194  Do not copy this code into any other unwinder! Inlined functions
195  are special; other unwinders must not have a dependency on the
196  previous frame's ID, and therefore can and should use
197  frame_unwind_got_register instead. */
198  return get_frame_register_value (this_frame, regnum);
199 }
200 
201 /* Check whether we are at an inlining site that does not already
202  have an associated frame. */
203 
204 static int
205 inline_frame_sniffer (const struct frame_unwind *self,
206  struct frame_info *this_frame,
207  void **this_cache)
208 {
209  CORE_ADDR this_pc;
210  const struct block *frame_block, *cur_block;
211  int depth;
212  struct frame_info *next_frame;
213  struct inline_state *state = find_inline_frame_state (inferior_ptid);
214 
215  this_pc = get_frame_address_in_block (this_frame);
216  frame_block = block_for_pc (this_pc);
217  if (frame_block == NULL)
218  return 0;
219 
220  /* Calculate DEPTH, the number of inlined functions at this
221  location. */
222  depth = 0;
223  cur_block = frame_block;
224  while (BLOCK_SUPERBLOCK (cur_block))
225  {
226  if (block_inlined_p (cur_block))
227  depth++;
228  else if (BLOCK_FUNCTION (cur_block) != NULL)
229  break;
230 
231  cur_block = BLOCK_SUPERBLOCK (cur_block);
232  }
233 
234  /* Check how many inlined functions already have frames. */
235  for (next_frame = get_next_frame (this_frame);
236  next_frame && get_frame_type (next_frame) == INLINE_FRAME;
237  next_frame = get_next_frame (next_frame))
238  {
239  gdb_assert (depth > 0);
240  depth--;
241  }
242 
243  /* If this is the topmost frame, or all frames above us are inlined,
244  then check whether we were requested to skip some frames (so they
245  can be stepped into later). */
246  if (state != NULL && state->skipped_frames > 0 && next_frame == NULL)
247  {
248  gdb_assert (depth >= state->skipped_frames);
249  depth -= state->skipped_frames;
250  }
251 
252  /* If all the inlined functions here already have frames, then pass
253  to the normal unwinder for this PC. */
254  if (depth == 0)
255  return 0;
256 
257  /* If the next frame is an inlined function, but not the outermost, then
258  we are the next outer. If it is not an inlined function, then we
259  are the innermost inlined function of a different real frame. */
260  return 1;
261 }
262 
263 const struct frame_unwind inline_frame_unwind = {
264  INLINE_FRAME,
268  NULL,
270 };
271 
272 /* Return non-zero if BLOCK, an inlined function block containing PC,
273  has a group of contiguous instructions starting at PC (but not
274  before it). */
275 
276 static int
278 {
279  const struct blockvector *bv;
280  struct block *new_block;
281 
282  bv = blockvector_for_pc (pc, NULL);
283  if (BLOCKVECTOR_MAP (bv) == NULL)
284  return 0;
285 
286  new_block = addrmap_find (BLOCKVECTOR_MAP (bv), pc - 1);
287  if (new_block == NULL)
288  return 1;
289 
290  if (new_block == block || contained_in (new_block, block))
291  return 0;
292 
293  /* The immediately preceding address belongs to a different block,
294  which is not a child of this one. Treat this as an entrance into
295  BLOCK. */
296  return 1;
297 }
298 
299 /* Skip all inlined functions whose call sites are at the current PC.
300  Frames for the hidden functions will not appear in the backtrace until the
301  user steps into them. */
302 
303 void
305 {
306  CORE_ADDR this_pc;
307  const struct block *frame_block, *cur_block;
308  struct symbol *last_sym = NULL;
309  int skip_count = 0;
310  struct inline_state *state;
311 
312  /* This function is called right after reinitializing the frame
313  cache. We try not to do more unwinding than absolutely
314  necessary, for performance. */
315  this_pc = get_frame_pc (get_current_frame ());
316  frame_block = block_for_pc (this_pc);
317 
318  if (frame_block != NULL)
319  {
320  cur_block = frame_block;
321  while (BLOCK_SUPERBLOCK (cur_block))
322  {
323  if (block_inlined_p (cur_block))
324  {
325  /* See comments in inline_frame_this_id about this use
326  of BLOCK_START. */
327  if (BLOCK_START (cur_block) == this_pc
328  || block_starting_point_at (this_pc, cur_block))
329  {
330  skip_count++;
331  last_sym = BLOCK_FUNCTION (cur_block);
332  }
333  else
334  break;
335  }
336  else if (BLOCK_FUNCTION (cur_block) != NULL)
337  break;
338 
339  cur_block = BLOCK_SUPERBLOCK (cur_block);
340  }
341  }
342 
343  gdb_assert (find_inline_frame_state (ptid) == NULL);
344  state = allocate_inline_frame_state (ptid);
345  state->skipped_frames = skip_count;
346  state->saved_pc = this_pc;
347  state->skipped_symbol = last_sym;
348 
349  if (skip_count != 0)
351 }
352 
353 /* Step into an inlined function by unhiding it. */
354 
355 void
357 {
358  struct inline_state *state = find_inline_frame_state (ptid);
359 
360  gdb_assert (state != NULL && state->skipped_frames > 0);
361  state->skipped_frames--;
363 }
364 
365 /* Return the number of hidden functions inlined into the current
366  frame. */
367 
368 int
370 {
371  struct inline_state *state = find_inline_frame_state (ptid);
372 
373  if (state == NULL)
374  return 0;
375  else
376  return state->skipped_frames;
377 }
378 
379 /* If one or more inlined functions are hidden, return the symbol for
380  the function inlined into the current frame. */
381 
382 struct symbol *
384 {
385  struct inline_state *state = find_inline_frame_state (ptid);
386 
387  gdb_assert (state != NULL);
388  return state->skipped_symbol;
389 }
390 
391 /* Return the number of functions inlined into THIS_FRAME. Some of
392  the callees may not have associated frames (see
393  skip_inline_frames). */
394 
395 int
396 frame_inlined_callees (struct frame_info *this_frame)
397 {
398  struct frame_info *next_frame;
399  int inline_count = 0;
400 
401  /* First count how many inlined functions at this PC have frames
402  above FRAME (are inlined into FRAME). */
403  for (next_frame = get_next_frame (this_frame);
404  next_frame && get_frame_type (next_frame) == INLINE_FRAME;
405  next_frame = get_next_frame (next_frame))
406  inline_count++;
407 
408  /* Simulate some most-inner inlined frames which were suppressed, so
409  they can be stepped into later. If we are unwinding already
410  outer frames from some non-inlined frame this does not apply. */
411  if (next_frame == NULL)
412  inline_count += inline_skipped_frames (inferior_ptid);
413 
414  return inline_count;
415 }
int frame_id_p(struct frame_id l)
Definition: frame.c:576
static int block_starting_point_at(CORE_ADDR pc, const struct block *block)
Definition: inline-frame.c:277
CORE_ADDR get_frame_address_in_block(struct frame_info *this_frame)
Definition: frame.c:2248
CORE_ADDR get_frame_pc(struct frame_info *frame)
Definition: frame.c:2217
int ptid_is_pid(ptid_t ptid)
Definition: ptid.c:86
struct frame_info * get_current_frame(void)
Definition: frame.c:1461
void clear_inline_frame_state(ptid_t ptid)
Definition: inline-frame.c:113
int ptid_equal(ptid_t ptid1, ptid_t ptid2)
Definition: ptid.c:76
bfd_vma CORE_ADDR
Definition: common-types.h:41
struct regcache * get_thread_regcache(ptid_t ptid)
Definition: regcache.c:529
void(* func)(char *)
#define VEC_unordered_remove(T, V, I)
Definition: vec.h:351
#define VEC_safe_push(T, V, O)
Definition: vec.h:260
CORE_ADDR saved_pc
Definition: inline-frame.c:50
#define BLOCK_START(bl)
Definition: block.h:116
const struct block * block_for_pc(CORE_ADDR pc)
Definition: block.c:282
Definition: ptid.h:35
#define BLOCK_FUNCTION(bl)
Definition: block.h:118
int frame_id_eq(struct frame_id l, struct frame_id r)
Definition: frame.c:604
enum frame_type get_frame_type(struct frame_info *frame)
Definition: frame.c:2463
#define VEC_iterate(T, V, I, P)
Definition: vec.h:165
struct value * get_frame_register_value(struct frame_info *frame, int regnum)
Definition: frame.c:1158
struct frame_id get_frame_id(struct frame_info *fi)
Definition: frame.c:473
static struct inline_state * allocate_inline_frame_state(ptid_t ptid)
Definition: inline-frame.c:97
int contained_in(const struct block *a, const struct block *b)
Definition: block.c:73
struct symbol * inline_skipped_symbol(ptid_t ptid)
Definition: inline-frame.c:383
int inline_skipped_frames(ptid_t ptid)
Definition: inline-frame.c:369
struct symbol * get_frame_function(struct frame_info *frame)
Definition: blockframe.c:118
#define BLOCK_SUPERBLOCK(bl)
Definition: block.h:119
struct frame_info * get_prev_frame_always(struct frame_info *this_frame)
Definition: frame.c:1965
static int inline_frame_sniffer(const struct frame_unwind *self, struct frame_info *this_frame, void **this_cache)
Definition: inline-frame.c:205
#define gdb_assert(expr)
Definition: gdb_assert.h:33
static void inline_frame_this_id(struct frame_info *this_frame, void **this_cache, struct frame_id *this_id)
Definition: inline-frame.c:148
int regnum
Definition: aarch64-tdep.c:69
void skip_inline_frames(ptid_t ptid)
Definition: inline-frame.c:304
Definition: block.h:60
Definition: value.c:172
int ptid_get_pid(ptid_t ptid)
Definition: ptid.c:52
static VEC(inline_state_s)
Definition: inline-frame.c:61
int frame_inlined_callees(struct frame_info *this_frame)
Definition: inline-frame.c:396
DEF_VEC_O(inline_state_s)
struct frame_info * get_next_frame(struct frame_info *this_frame)
Definition: frame.c:1668
int block_inlined_p(const struct block *bl)
Definition: block.c:126
#define SYMBOL_BLOCK_VALUE(symbol)
Definition: symtab.h:185
CORE_ADDR regcache_read_pc(struct regcache *regcache)
Definition: regcache.c:1174
ptid_t inferior_ptid
Definition: infcmd.c:124
struct symbol * skipped_symbol
Definition: inline-frame.c:55
#define VEC_free(T, V)
Definition: vec.h:180
int skipped_frames
Definition: inline-frame.c:44
enum unwind_stop_reason default_frame_unwind_stop_reason(struct frame_info *this_frame, void **this_cache)
Definition: frame-unwind.c:180
const struct frame_id outer_frame_id
Definition: frame.c:507
static struct value * inline_frame_prev_register(struct frame_info *this_frame, void **this_cache, int regnum)
Definition: inline-frame.c:184
Definition: symtab.h:703
void * addrmap_find(struct addrmap *map, CORE_ADDR addr)
Definition: addrmap.c:59
#define BLOCKVECTOR_MAP(blocklist)
Definition: block.h:137
void reinit_frame_cache(void)
Definition: frame.c:1687
const struct blockvector * blockvector_for_pc(CORE_ADDR pc, const struct block **pblock)
Definition: block.c:257
ptid_t minus_one_ptid
Definition: ptid.c:26
mach_port_t mach_port_t name mach_port_t mach_port_t name error_t int int rusage_t pid_t pid
Definition: gnu-nat.c:1818
static struct block * new_block(enum block_type)
Definition: mdebugread.c:4833
void step_into_inline_frame(ptid_t ptid)
Definition: inline-frame.c:356