Bug Summary

File:src/gnu/usr.bin/binutils-2.17/gas/frags.c
Warning:line 74, column 3
Null pointer passed as 1st argument to memory set function

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name frags.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/binutils-2.17/obj/gas -resource-dir /usr/local/lib/clang/13.0.0 -D HAVE_CONFIG_H -I . -I /usr/src/gnu/usr.bin/binutils-2.17/gas -I . -D _GNU_SOURCE -I . -I /usr/src/gnu/usr.bin/binutils-2.17/gas -I ../bfd -I /usr/src/gnu/usr.bin/binutils-2.17/gas/config -I /usr/src/gnu/usr.bin/binutils-2.17/gas/../include -I /usr/src/gnu/usr.bin/binutils-2.17/gas/.. -I /usr/src/gnu/usr.bin/binutils-2.17/gas/../bfd -I /usr/src/gnu/usr.bin/binutils-2.17/gas/../intl -I ../intl -D LOCALEDIR="/usr/share/locale" -D PIE_DEFAULT=1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-null-pointer-arithmetic -fdebug-compilation-dir=/usr/src/gnu/usr.bin/binutils-2.17/obj/gas -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/gnu/usr.bin/binutils-2.17/gas/frags.c
1/* frags.c - manage frags -
2 Copyright 1987, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2003, 2004, 2005, 2006
4 Free Software Foundation, Inc.
5
6 This file is part of GAS, the GNU Assembler.
7
8 GAS is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
11 any later version.
12
13 GAS is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with GAS; see the file COPYING. If not, write to the Free
20 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
21 02110-1301, USA. */
22
23#include "as.h"
24#include "subsegs.h"
25#include "obstack.h"
26
27extern fragS zero_address_frag;
28extern fragS bss_address_frag;
29
30/* Initialization for frag routines. */
31
32void
33frag_init (void)
34{
35 zero_address_frag.fr_type = rs_fill;
36 bss_address_frag.fr_type = rs_fill;
37}
38
39/* Check that we're not trying to assemble into a section that can't
40 allocate frags (currently, this is only possible in the absolute
41 section), or into an mri common. */
42
43static void
44frag_alloc_check (const struct obstack *ob)
45{
46 if (ob->chunk_size == 0)
47 {
48 as_bad (_("attempt to allocate data in absolute section")("attempt to allocate data in absolute section"));
49 subseg_set (text_section, 0);
50 }
51
52 if (mri_common_symbol != NULL((void*)0))
53 {
54 as_bad (_("attempt to allocate data in common section")("attempt to allocate data in common section"));
55 mri_common_symbol = NULL((void*)0);
56 }
57}
58
59/* Allocate a frag on the specified obstack.
60 Call this routine from everywhere else, so that all the weird alignment
61 hackery can be done in just one place. */
62
63fragS *
64frag_alloc (struct obstack *ob)
65{
66 fragS *ptr;
67 int oalign;
68
69 (void) obstack_alloc (ob, 0)__extension__ ({ struct obstack *__h = (ob); __extension__ ({
struct obstack *__o = (__h); int __len = ((0)); if (__o->
chunk_limit - __o->next_free < __len) _obstack_newchunk
(__o, __len); ((__o)->next_free += (__len)); (void) 0; })
; __extension__ ({ struct obstack *__o1 = (__h); void *value;
value = (void *) __o1->object_base; if (__o1->next_free
== value) __o1->maybe_empty_object = 1; __o1->next_free
= (((((__o1->next_free) - (char *) 0)+__o1->alignment_mask
) & ~ (__o1->alignment_mask)) + (char *) 0); if (__o1->
next_free - (char *)__o1->chunk > __o1->chunk_limit -
(char *)__o1->chunk) __o1->next_free = __o1->chunk_limit
; __o1->object_base = __o1->next_free; value; }); });
17
←
Assuming the condition is true
→
18
←
Taking true branch
→
19
←
Assuming 'value' is not equal to field 'next_free'
→
20
←
Taking false branch
→
21
←
Assuming the condition is false
→
22
←
Taking false branch
→
70 oalign = obstack_alignment_mask (ob)((ob)->alignment_mask);
71 obstack_alignment_mask (ob)((ob)->alignment_mask) = 0;
72 ptr = (fragS *) obstack_alloc (ob, SIZEOF_STRUCT_FRAG)__extension__ ({ struct obstack *__h = (ob); __extension__ ({
struct obstack *__o = (__h); int __len = ((((char *) zero_address_frag
.fr_literal - (char *) &zero_address_frag))); if (__o->
chunk_limit - __o->next_free < __len) _obstack_newchunk
(__o, __len); ((__o)->next_free += (__len)); (void) 0; })
; __extension__ ({ struct obstack *__o1 = (__h); void *value;
value = (void *) __o1->object_base; if (__o1->next_free
== value) __o1->maybe_empty_object = 1; __o1->next_free
= (((((__o1->next_free) - (char *) 0)+__o1->alignment_mask
) & ~ (__o1->alignment_mask)) + (char *) 0); if (__o1->
next_free - (char *)__o1->chunk > __o1->chunk_limit -
(char *)__o1->chunk) __o1->next_free = __o1->chunk_limit
; __o1->object_base = __o1->next_free; value; }); });
23
←
Assuming the condition is false
→
24
←
Taking false branch
→
25
←
Taking true branch
→
26
←
Assuming the condition is false
→
27
←
Taking false branch
→
28
←
Null pointer value stored to 'ptr'
→
73 obstack_alignment_mask (ob)((ob)->alignment_mask) = oalign;
74 memset (ptr, 0, SIZEOF_STRUCT_FRAG((char *) zero_address_frag.fr_literal - (char *) &zero_address_frag
));
29
←
Null pointer passed as 1st argument to memory set function
75 return ptr;
76}
77
78/* Try to augment current frag by nchars chars.
79 If there is no room, close of the current frag with a ".fill 0"
80 and begin a new frag. Unless the new frag has nchars chars available
81 do not return. Do not set up any fields of *now_frag. */
82
83void
84frag_grow (unsigned int nchars)
85{
86 if (obstack_room (&frchain_now->frch_obstack)__extension__ ({ struct obstack *__o = (&frchain_now->
frch_obstack); (unsigned) (__o->chunk_limit - __o->next_free
); }) < nchars)
87 {
88 unsigned int n;
89 long oldc;
90
91 frag_wane (frag_now);
92 frag_new (0);
93 oldc = frchain_now->frch_obstack.chunk_size;
94 /* Try to allocate a bit more than needed right now. But don't do
95 this if we would waste too much memory. Especially necessary
96 for extremely big (like 2GB initialized) frags. */
97 if (nchars < 0x10000)
98 frchain_now->frch_obstack.chunk_size = 2 * nchars;
99 else
100 frchain_now->frch_obstack.chunk_size = nchars + 0x10000;
101 frchain_now->frch_obstack.chunk_size += SIZEOF_STRUCT_FRAG((char *) zero_address_frag.fr_literal - (char *) &zero_address_frag
);
102 if (frchain_now->frch_obstack.chunk_size > 0)
103 while ((n = obstack_room (&frchain_now->frch_obstack)__extension__ ({ struct obstack *__o = (&frchain_now->
frch_obstack); (unsigned) (__o->chunk_limit - __o->next_free
); })) < nchars
104 && (unsigned long) frchain_now->frch_obstack.chunk_size > nchars)
105 {
106 frag_wane (frag_now);
107 frag_new (0);
108 }
109 frchain_now->frch_obstack.chunk_size = oldc;
110 }
111 if (obstack_room (&frchain_now->frch_obstack)__extension__ ({ struct obstack *__o = (&frchain_now->
frch_obstack); (unsigned) (__o->chunk_limit - __o->next_free
); }) < nchars)
112 as_fatal (_("can't extend frag %u chars")("can't extend frag %u chars"), nchars);
113}
114
115/* Call this to close off a completed frag, and start up a new (empty)
116 frag, in the same subsegment as the old frag.
117 [frchain_now remains the same but frag_now is updated.]
118 Because this calculates the correct value of fr_fix by
119 looking at the obstack 'frags', it needs to know how many
120 characters at the end of the old frag belong to the maximal
121 variable part; The rest must belong to fr_fix.
122 It doesn't actually set up the old frag's fr_var. You may have
123 set fr_var == 1, but allocated 10 chars to the end of the frag;
124 In this case you pass old_frags_var_max_size == 10.
125 In fact, you may use fr_var for something totally unrelated to the
126 size of the variable part of the frag; None of the generic frag
127 handling code makes use of fr_var.
128
129 Make a new frag, initialising some components. Link new frag at end
130 of frchain_now. */
131
132void
133frag_new (int old_frags_var_max_size
134 /* Number of chars (already allocated on obstack frags) in
135 variable_length part of frag. */)
136{
137 fragS *former_last_fragP;
138 frchainS *frchP;
139
140 assert (frchain_now->frch_last == frag_now)((void) ((frchain_now->frch_last == frag_now) ? 0 : (as_assert
("/usr/src/gnu/usr.bin/binutils-2.17/gas/frags.c", 140, __PRETTY_FUNCTION__
), 0)));
4
←
Assuming 'frag_now' is not equal to field 'frch_last'
→
5
←
'?' condition is false
→
141
142 /* Fix up old frag's fr_fix. */
143 frag_now->fr_fix = frag_now_fix_octets () - old_frags_var_max_size;
144 /* Make sure its type is valid. */
145 assert (frag_now->fr_type != 0)((void) ((frag_now->fr_type != 0) ? 0 : (as_assert ("/usr/src/gnu/usr.bin/binutils-2.17/gas/frags.c"
, 145, __PRETTY_FUNCTION__), 0)));
6
←
Assuming field 'fr_type' is not equal to 0
→
7
←
'?' condition is true
→
146
147 /* This will align the obstack so the next struct we allocate on it
148 will begin at a correct boundary. */
149 obstack_finish (&frchain_now->frch_obstack)__extension__ ({ struct obstack *__o1 = (&frchain_now->
frch_obstack); void *value; value = (void *) __o1->object_base
; if (__o1->next_free == value) __o1->maybe_empty_object
= 1; __o1->next_free = (((((__o1->next_free) - (char *
) 0)+__o1->alignment_mask) & ~ (__o1->alignment_mask
)) + (char *) 0); if (__o1->next_free - (char *)__o1->chunk
> __o1->chunk_limit - (char *)__o1->chunk) __o1->
next_free = __o1->chunk_limit; __o1->object_base = __o1
->next_free; value; });
8
←
Assuming 'value' is not equal to field 'next_free'
→
9
←
Taking false branch
→
10
←
Assuming the condition is false
→
11
←
Taking false branch
→
150 frchP = frchain_now;
151 know (frchP);
152 former_last_fragP = frchP->frch_last;
153 assert (former_last_fragP != 0)((void) ((former_last_fragP != 0) ? 0 : (as_assert ("/usr/src/gnu/usr.bin/binutils-2.17/gas/frags.c"
, 153, __PRETTY_FUNCTION__), 0)));
12
←
Assuming 'former_last_fragP' is not equal to null
→
13
←
'?' condition is true
→
154 assert (former_last_fragP == frag_now)((void) ((former_last_fragP == frag_now) ? 0 : (as_assert ("/usr/src/gnu/usr.bin/binutils-2.17/gas/frags.c"
, 154, __PRETTY_FUNCTION__), 0)));
14
←
Assuming 'former_last_fragP' is equal to 'frag_now'
→
15
←
'?' condition is true
→
155 frag_now = frag_alloc (&frchP->frch_obstack);
16
←
Calling 'frag_alloc'
→
156
157 as_where (&frag_now->fr_file, &frag_now->fr_line);
158
159 /* Generally, frag_now->points to an address rounded up to next
160 alignment. However, characters will add to obstack frags
161 IMMEDIATELY after the struct frag, even if they are not starting
162 at an alignment address. */
163 former_last_fragP->fr_next = frag_now;
164 frchP->frch_last = frag_now;
165
166#ifndef NO_LISTING
167 {
168 extern struct list_info_struct *listing_tail;
169 frag_now->line = listing_tail;
170 }
171#endif
172
173 assert (frchain_now->frch_last == frag_now)((void) ((frchain_now->frch_last == frag_now) ? 0 : (as_assert
("/usr/src/gnu/usr.bin/binutils-2.17/gas/frags.c", 173, __PRETTY_FUNCTION__
), 0)));
174
175 frag_now->fr_next = NULL((void*)0);
176}
177
178/* Start a new frag unless we have n more chars of room in the current frag.
179 Close off the old frag with a .fill 0.
180
181 Return the address of the 1st char to write into. Advance
182 frag_now_growth past the new chars. */
183
184char *
185frag_more (int nchars)
186{
187 register char *retval;
188
189 frag_alloc_check (&frchain_now->frch_obstack);
190 frag_grow (nchars);
191 retval = obstack_next_free (&frchain_now->frch_obstack)((&frchain_now->frch_obstack)->next_free);
192 obstack_blank_fast (&frchain_now->frch_obstack, nchars)((&frchain_now->frch_obstack)->next_free += (nchars
));
193 return (retval);
194}
195
196/* Start a new frag unless we have max_chars more chars of room in the
197 current frag. Close off the old frag with a .fill 0.
198
199 Set up a machine_dependent relaxable frag, then start a new frag.
200 Return the address of the 1st char of the var part of the old frag
201 to write into. */
202
203char *
204frag_var (relax_stateT type, int max_chars, int var, relax_substateT subtype,
205 symbolS *symbol, offsetT offset, char *opcode)
206{
207 register char *retval;
208
209 frag_grow (max_chars);
210 retval = obstack_next_free (&frchain_now->frch_obstack)((&frchain_now->frch_obstack)->next_free);
211 obstack_blank_fast (&frchain_now->frch_obstack, max_chars)((&frchain_now->frch_obstack)->next_free += (max_chars
));
212 frag_now->fr_var = var;
213 frag_now->fr_type = type;
214 frag_now->fr_subtype = subtype;
215 frag_now->fr_symbol = symbol;
216 frag_now->fr_offset = offset;
217 frag_now->fr_opcode = opcode;
218#ifdef USING_CGEN
219 frag_now->fr_cgen.insn = 0;
220 frag_now->fr_cgen.opindex = 0;
221 frag_now->fr_cgen.opinfo = 0;
222#endif
223#ifdef TC_FRAG_INIT
224 TC_FRAG_INIT (frag_now);
225#endif
226 as_where (&frag_now->fr_file, &frag_now->fr_line);
227 frag_new (max_chars);
228 return (retval);
229}
230
231/* OVE: This variant of frag_var assumes that space for the tail has been
232 allocated by caller.
233 No call to frag_grow is done. */
234
235char *
236frag_variant (relax_stateT type, int max_chars, int var,
237 relax_substateT subtype, symbolS *symbol, offsetT offset,
238 char *opcode)
239{
240 register char *retval;
241
242 retval = obstack_next_free (&frchain_now->frch_obstack)((&frchain_now->frch_obstack)->next_free);
243 frag_now->fr_var = var;
244 frag_now->fr_type = type;
245 frag_now->fr_subtype = subtype;
246 frag_now->fr_symbol = symbol;
247 frag_now->fr_offset = offset;
248 frag_now->fr_opcode = opcode;
249#ifdef USING_CGEN
250 frag_now->fr_cgen.insn = 0;
251 frag_now->fr_cgen.opindex = 0;
252 frag_now->fr_cgen.opinfo = 0;
253#endif
254#ifdef TC_FRAG_INIT
255 TC_FRAG_INIT (frag_now);
256#endif
257 as_where (&frag_now->fr_file, &frag_now->fr_line);
258 frag_new (max_chars);
259 return (retval);
260}
261
262/* Reduce the variable end of a frag to a harmless state. */
263
264void
265frag_wane (register fragS *fragP)
266{
267 fragP->fr_type = rs_fill;
268 fragP->fr_offset = 0;
269 fragP->fr_var = 0;
270}
271
272/* Return the number of bytes by which the current frag can be grown. */
273
274int
275frag_room (void)
276{
277 return obstack_room (&frchain_now->frch_obstack)__extension__ ({ struct obstack *__o = (&frchain_now->
frch_obstack); (unsigned) (__o->chunk_limit - __o->next_free
); });
278}
279
280/* Make an alignment frag. The size of this frag will be adjusted to
281 force the next frag to have the appropriate alignment. ALIGNMENT
282 is the power of two to which to align. FILL_CHARACTER is the
283 character to use to fill in any bytes which are skipped. MAX is
284 the maximum number of characters to skip when doing the alignment,
285 or 0 if there is no maximum. */
286
287void
288frag_align (int alignment, int fill_character, int max)
289{
290 if (now_seg == absolute_section((asection *) &bfd_abs_section))
291 {
292 addressT new_off;
293 addressT mask;
294
295 mask = (~(addressT) 0) << alignment;
296 new_off = (abs_section_offset + ~mask) & mask;
297 if (max == 0 || new_off - abs_section_offset <= (addressT) max)
298 abs_section_offset = new_off;
299 }
300 else
301 {
302 char *p;
303
304 p = frag_var (rs_align, 1, 1, (relax_substateT) max,
305 (symbolS *) 0, (offsetT) alignment, (char *) 0);
306 *p = fill_character;
307 }
308}
309
310/* Make an alignment frag like frag_align, but fill with a repeating
311 pattern rather than a single byte. ALIGNMENT is the power of two
312 to which to align. FILL_PATTERN is the fill pattern to repeat in
313 the bytes which are skipped. N_FILL is the number of bytes in
314 FILL_PATTERN. MAX is the maximum number of characters to skip when
315 doing the alignment, or 0 if there is no maximum. */
316
317void
318frag_align_pattern (int alignment, const char *fill_pattern,
319 int n_fill, int max)
320{
321 char *p;
322
323 p = frag_var (rs_align, n_fill, n_fill, (relax_substateT) max,
324 (symbolS *) 0, (offsetT) alignment, (char *) 0);
325 memcpy (p, fill_pattern, n_fill);
326}
327
328/* The NOP_OPCODE is for the alignment fill value. Fill it with a nop
329 instruction so that the disassembler does not choke on it. */
330#ifndef NOP_OPCODE(char) 0x90
331#define NOP_OPCODE(char) 0x90 0x00
332#endif
333
334/* Use this to restrict the amount of memory allocated for representing
335 the alignment code. Needs to be large enough to hold any fixed sized
336 prologue plus the replicating portion. */
337#ifndef MAX_MEM_FOR_RS_ALIGN_CODE15
338 /* Assume that if HANDLE_ALIGN is not defined then no special action
339 is required to code fill, which means that we get just repeat the
340 one NOP_OPCODE byte. */
341# ifndef HANDLE_ALIGN
342# define MAX_MEM_FOR_RS_ALIGN_CODE15 1
343# else
344# define MAX_MEM_FOR_RS_ALIGN_CODE15 ((1 << alignment) - 1)
345# endif
346#endif
347
348void
349frag_align_code (int alignment, int max)
350{
351 char *p;
352
353 p = frag_var (rs_align_code, MAX_MEM_FOR_RS_ALIGN_CODE15, 1,
354 (relax_substateT) max, (symbolS *) 0,
355 (offsetT) alignment, (char *) 0);
356 *p = NOP_OPCODE(char) 0x90;
357}
358
359addressT
360frag_now_fix_octets (void)
361{
362 if (now_seg == absolute_section((asection *) &bfd_abs_section))
363 return abs_section_offset;
364
365 return ((char *) obstack_next_free (&frchain_now->frch_obstack)((&frchain_now->frch_obstack)->next_free)
366 - frag_now->fr_literal);
367}
368
369addressT
370frag_now_fix (void)
371{
372 return frag_now_fix_octets () / OCTETS_PER_BYTE(1<<0);
373}
374
375void
376frag_append_1_char (int datum)
377{
378 frag_alloc_check (&frchain_now->frch_obstack);
379 if (obstack_room (&frchain_now->frch_obstack)__extension__ ({ struct obstack *__o = (&frchain_now->
frch_obstack); (unsigned) (__o->chunk_limit - __o->next_free
); }) <= 1)
1
Assuming the condition is true
→
2
←
Taking true branch
→
380 {
381 frag_wane (frag_now);
382 frag_new (0);
3
←
Calling 'frag_new'
→
383 }
384 obstack_1grow (&frchain_now->frch_obstack, datum)__extension__ ({ struct obstack *__o = (&frchain_now->
frch_obstack); if (__o->next_free + 1 > __o->chunk_limit
) _obstack_newchunk (__o, 1); (*((__o)->next_free)++ = (datum
)); (void) 0; });
385}
386
387/* Return TRUE if FRAG1 and FRAG2 have a fixed relationship between
388 their start addresses. Set OFFSET to the difference in address
389 not already accounted for in the frag FR_ADDRESS. */
390
391bfd_boolean
392frag_offset_fixed_p (fragS *frag1, fragS *frag2, bfd_vma *offset)
393{
394 fragS *frag;
395 bfd_vma off;
396
397 /* Start with offset initialised to difference between the two frags.
398 Prior to assigning frag addresses this will be zero. */
399 off = frag1->fr_address - frag2->fr_address;
400 if (frag1 == frag2)
401 {
402 *offset = off;
403 return TRUE1;
404 }
405
406 /* Maybe frag2 is after frag1. */
407 frag = frag1;
408 while (frag->fr_type == rs_fill)
409 {
410 off += frag->fr_fix + frag->fr_offset * frag->fr_var;
411 frag = frag->fr_next;
412 if (frag == NULL((void*)0))
413 break;
414 if (frag == frag2)
415 {
416 *offset = off;
417 return TRUE1;
418 }
419 }
420
421 /* Maybe frag1 is after frag2. */
422 off = frag1->fr_address - frag2->fr_address;
423 frag = frag2;
424 while (frag->fr_type == rs_fill)
425 {
426 off -= frag->fr_fix + frag->fr_offset * frag->fr_var;
427 frag = frag->fr_next;
428 if (frag == NULL((void*)0))
429 break;
430 if (frag == frag1)
431 {
432 *offset = off;
433 return TRUE1;
434 }
435 }
436
437 return FALSE0;
438}