Bug Summary

File:build/libcpp/mkdeps.c
Warning:line 439, column 4
Value stored to 'column' is never read

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-unknown-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name mkdeps.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -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 -analyzer-config-compatibility-mode=true -mrelocation-model static -mframe-pointer=none -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -fno-split-dwarf-inlining -debugger-tuning=gdb -resource-dir /usr/lib64/clang/11.0.0 -I /home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/build/libcpp -I . -I /home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/build/libcpp/../include -I /home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/build/libcpp/include -I /home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/build/libcpp -I . -I /home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/build/libcpp/../include -I /home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/build/libcpp/include -internal-isystem /usr/bin/../lib64/gcc/x86_64-suse-linux/10/../../../../include/c++/10 -internal-isystem /usr/bin/../lib64/gcc/x86_64-suse-linux/10/../../../../include/c++/10/x86_64-suse-linux -internal-isystem /usr/bin/../lib64/gcc/x86_64-suse-linux/10/../../../../include/c++/10/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib64/clang/11.0.0/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-narrowing -Wwrite-strings -Wno-long-long -fdeprecated-macro -fdebug-compilation-dir /home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/objdir/build-x86_64-pc-linux-gnu/libcpp -ferror-limit 19 -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=plist-html -analyzer-config silence-checkers=core.NullDereference -faddrsig -o /home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/objdir/clang-static-analyzer/2021-01-16-135054-17580-1/report-rqlr7v.plist -x c++ /home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/build/libcpp/mkdeps.c
1/* Dependency generator for Makefile fragments.
2 Copyright (C) 2000-2021 Free Software Foundation, Inc.
3 Contributed by Zack Weinberg, Mar 2000
4
5This program is free software; you can redistribute it and/or modify it
6under the terms of the GNU General Public License as published by the
7Free Software Foundation; either version 3, or (at your option) any
8later version.
9
10This program is distributed in the hope that it will be useful,
11but WITHOUT ANY WARRANTY; without even the implied warranty of
12MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13GNU General Public License for more details.
14
15You should have received a copy of the GNU General Public License
16along with this program; see the file COPYING3. If not see
17<http://www.gnu.org/licenses/>.
18
19 In other words, you are welcome to use, share and improve this program.
20 You are forbidden to forbid anyone else to use, share and improve
21 what you give them. Help stamp out software-hoarding! */
22
23#include "config.h"
24#include "system.h"
25#include "mkdeps.h"
26#include "internal.h"
27
28/* Not set up to just include std::vector et al, here's a simple
29 implementation. */
30
31/* Keep this structure local to this file, so clients don't find it
32 easy to start making assumptions. */
33class mkdeps
34{
35public:
36 /* T has trivial cctor & dtor. */
37 template <typename T>
38 class vec
39 {
40 private:
41 T *ary;
42 unsigned num;
43 unsigned alloc;
44
45 public:
46 vec ()
47 : ary (NULL__null), num (0), alloc (0)
48 {}
49 ~vec ()
50 {
51 XDELETEVEC (ary)free ((void*) (ary));
52 }
53
54 public:
55 unsigned size () const
56 {
57 return num;
58 }
59 const T &operator[] (unsigned ix) const
60 {
61 return ary[ix];
62 }
63 T &operator[] (unsigned ix)
64 {
65 return ary[ix];
66 }
67 void push (const T &elt)
68 {
69 if (num == alloc)
70 {
71 alloc = alloc ? alloc * 2 : 16;
72 ary = XRESIZEVEC (T, ary, alloc)((T *) xrealloc ((void *) (ary), sizeof (T) * (alloc)));
73 }
74 ary[num++] = elt;
75 }
76 };
77 struct velt
78 {
79 const char *str;
80 size_t len;
81 };
82
83 mkdeps ()
84 : module_name (NULL__null), cmi_name (NULL__null), is_header_unit (false), quote_lwm (0)
85 {
86 }
87 ~mkdeps ()
88 {
89 unsigned int i;
90
91 for (i = targets.size (); i--;)
92 free (const_cast <char *> (targets[i]));
93 for (i = deps.size (); i--;)
94 free (const_cast <char *> (deps[i]));
95 for (i = vpath.size (); i--;)
96 XDELETEVEC (vpath[i].str)free ((void*) (vpath[i].str));
97 for (i = modules.size (); i--;)
98 XDELETEVEC (modules[i])free ((void*) (modules[i]));
99 XDELETEVEC (module_name)free ((void*) (module_name));
100 free (const_cast <char *> (cmi_name));
101 }
102
103public:
104 vec<const char *> targets;
105 vec<const char *> deps;
106 vec<velt> vpath;
107 vec<const char *> modules;
108
109public:
110 const char *module_name;
111 const char *cmi_name;
112 bool is_header_unit;
113 unsigned short quote_lwm;
114};
115
116/* Apply Make quoting to STR, TRAIL. Note that it's not possible to
117 quote all such characters - e.g. \n, %, *, ?, [, \ (in some
118 contexts), and ~ are not properly handled. It isn't possible to
119 get this right in any current version of Make. (??? Still true?
120 Old comment referred to 3.76.1.) */
121
122static const char *
123munge (const char *str, const char *trail = nullptr)
124{
125 static unsigned alloc;
126 static char *buf;
127 unsigned dst = 0;
128
129 for (; str; str = trail, trail = nullptr)
130 {
131 unsigned slashes = 0;
132 char c;
133 for (const char *probe = str; (c = *probe++);)
134 {
135 if (alloc < dst + 4 + slashes)
136 {
137 alloc = alloc * 2 + 32;
138 buf = XRESIZEVEC (char, buf, alloc)((char *) xrealloc ((void *) (buf), sizeof (char) * (alloc)));
139 }
140
141 switch (c)
142 {
143 case '\\':
144 slashes++;
145 break;
146
147 case '$':
148 buf[dst++] = '$';
149 goto def;
150
151 case ' ':
152 case '\t':
153 /* GNU make uses a weird quoting scheme for white space.
154 A space or tab preceded by 2N+1 backslashes
155 represents N backslashes followed by space; a space
156 or tab preceded by 2N backslashes represents N
157 backslashes at the end of a file name; and
158 backslashes in other contexts should not be
159 doubled. */
160 while (slashes--)
161 buf[dst++] = '\\';
162 /* FALLTHROUGH */
163
164 case '#':
165 buf[dst++] = '\\';
166 /* FALLTHROUGH */
167
168 default:
169 def:
170 slashes = 0;
171 break;
172 }
173
174 buf[dst++] = c;
175 }
176 }
177
178 buf[dst] = 0;
179 return buf;
180}
181
182/* If T begins with any of the partial pathnames listed in d->vpathv,
183 then advance T to point beyond that pathname. */
184static const char *
185apply_vpath (class mkdeps *d, const char *t)
186{
187 if (unsigned len = d->vpath.size ())
188 for (unsigned i = len; i--;)
189 {
190 if (!filename_ncmp (d->vpath[i].str, t, d->vpath[i].len))
191 {
192 const char *p = t + d->vpath[i].len;
193 if (!IS_DIR_SEPARATOR (*p)(((*p) == '/') || (((*p) == '\\') && (0))))
194 goto not_this_one;
195
196 /* Do not simplify $(vpath)/../whatever. ??? Might not
197 be necessary. */
198 if (p[1] == '.' && p[2] == '.' && IS_DIR_SEPARATOR (p[3])(((p[3]) == '/') || (((p[3]) == '\\') && (0))))
199 goto not_this_one;
200
201 /* found a match */
202 t = t + d->vpath[i].len + 1;
203 break;
204 }
205 not_this_one:;
206 }
207
208 /* Remove leading ./ in any case. */
209 while (t[0] == '.' && IS_DIR_SEPARATOR (t[1])(((t[1]) == '/') || (((t[1]) == '\\') && (0))))
210 {
211 t += 2;
212 /* If we removed a leading ./, then also remove any /s after the
213 first. */
214 while (IS_DIR_SEPARATOR (t[0])(((t[0]) == '/') || (((t[0]) == '\\') && (0))))
215 ++t;
216 }
217
218 return t;
219}
220
221/* Public routines. */
222
223class mkdeps *
224deps_init (void)
225{
226 return new mkdeps ();
227}
228
229void
230deps_free (class mkdeps *d)
231{
232 delete d;
233}
234
235/* Adds a target T. We make a copy, so it need not be a permanent
236 string. QUOTE is true if the string should be quoted. */
237void
238deps_add_target (class mkdeps *d, const char *t, int quote)
239{
240 t = xstrdup (apply_vpath (d, t));
241
242 if (!quote)
243 {
244 /* Sometimes unquoted items are added after quoted ones.
245 Swap out the lowest quoted. */
246 if (d->quote_lwm != d->targets.size ())
247 {
248 const char *lowest = d->targets[d->quote_lwm];
249 d->targets[d->quote_lwm] = t;
250 t = lowest;
251 }
252 d->quote_lwm++;
253 }
254
255 d->targets.push (t);
256}
257
258/* Sets the default target if none has been given already. An empty
259 string as the default target in interpreted as stdin. The string
260 is quoted for MAKE. */
261void
262deps_add_default_target (class mkdeps *d, const char *tgt)
263{
264 /* Only if we have no targets. */
265 if (d->targets.size ())
266 return;
267
268 if (tgt[0] == '\0')
269 d->targets.push (xstrdup ("-"));
270 else
271 {
272#ifndef TARGET_OBJECT_SUFFIX".o"
273# define TARGET_OBJECT_SUFFIX".o" ".o"
274#endif
275 const char *start = lbasename (tgt);
276 char *o = (char *) alloca (strlen (start)__builtin_alloca(strlen (start) + strlen (".o") + 1)
277 + strlen (TARGET_OBJECT_SUFFIX) + 1)__builtin_alloca(strlen (start) + strlen (".o") + 1);
278 char *suffix;
279
280 strcpy (o, start);
281
282 suffix = strrchr (o, '.');
283 if (!suffix)
284 suffix = o + strlen (o);
285 strcpy (suffix, TARGET_OBJECT_SUFFIX".o");
286
287 deps_add_target (d, o, 1);
288 }
289}
290
291void
292deps_add_dep (class mkdeps *d, const char *t)
293{
294 gcc_assert (*t)((void)(!(*t) ? fancy_abort ("/home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/build/libcpp/mkdeps.c"
, 294, __FUNCTION__), 0 : 0))
;
295
296 t = apply_vpath (d, t);
297
298 d->deps.push (xstrdup (t));
299}
300
301void
302deps_add_vpath (class mkdeps *d, const char *vpath)
303{
304 const char *elem, *p;
305
306 for (elem = vpath; *elem; elem = p)
307 {
308 for (p = elem; *p && *p != ':'; p++)
309 continue;
310 mkdeps::velt elt;
311 elt.len = p - elem;
312 char *str = XNEWVEC (char, elt.len + 1)((char *) xmalloc (sizeof (char) * (elt.len + 1)));
313 elt.str = str;
314 memcpy (str, elem, elt.len);
315 str[elt.len] = '\0';
316 if (*p == ':')
317 p++;
318
319 d->vpath.push (elt);
320 }
321}
322
323/* Add a new module target (there can only be one). M is the module
324 name. */
325
326void
327deps_add_module_target (struct mkdeps *d, const char *m,
328 const char *cmi, bool is_header_unit)
329{
330 gcc_assert (!d->module_name)((void)(!(!d->module_name) ? fancy_abort ("/home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-clang-static-analyzer/build/libcpp/mkdeps.c"
, 330, __FUNCTION__), 0 : 0))
;
331
332 d->module_name = xstrdup (m);
333 d->is_header_unit = is_header_unit;
334 d->cmi_name = xstrdup (cmi);
335}
336
337/* Add a new module dependency. M is the module name. */
338
339void
340deps_add_module_dep (struct mkdeps *d, const char *m)
341{
342 d->modules.push (xstrdup (m));
343}
344
345/* Write NAME, with a leading space to FP, a Makefile. Advance COL as
346 appropriate, wrap at COLMAX, returning new column number. Iff
347 QUOTE apply quoting. Append TRAIL. */
348
349static unsigned
350make_write_name (const char *name, FILE *fp, unsigned col, unsigned colmax,
351 bool quote = true, const char *trail = NULL__null)
352{
353 if (quote)
354 name = munge (name, trail);
355 unsigned size = strlen (name);
356
357 if (col)
358 {
359 if (colmax && col + size> colmax)
360 {
361 fputs (" \\\n", fp)fputs_unlocked (" \\\n", fp);
362 col = 0;
363 }
364 col++;
365 fputs (" ", fp)fputs_unlocked (" ", fp);
366 }
367
368 col += size;
369 fputs (name, fp)fputs_unlocked (name, fp);
370
371 return col;
372}
373
374/* Write all the names in VEC via make_write_name. */
375
376static unsigned
377make_write_vec (const mkdeps::vec<const char *> &vec, FILE *fp,
378 unsigned col, unsigned colmax, unsigned quote_lwm = 0,
379 const char *trail = NULL__null)
380{
381 for (unsigned ix = 0; ix != vec.size (); ix++)
382 col = make_write_name (vec[ix], fp, col, colmax, ix >= quote_lwm, trail);
383 return col;
384}
385
386/* Write the dependencies to a Makefile. If PHONY is true, add
387 .PHONY targets for all the dependencies too. */
388
389static void
390make_write (const cpp_reader *pfile, FILE *fp, unsigned int colmax)
391{
392 const mkdeps *d = pfile->deps;
393
394 unsigned column = 0;
395 if (colmax && colmax < 34)
396 colmax = 34;
397
398 if (d->deps.size ())
399 {
400 column = make_write_vec (d->targets, fp, 0, colmax, d->quote_lwm);
401 if (CPP_OPTION (pfile, deps.modules)((pfile)->opts.deps.modules) && d->cmi_name)
402 column = make_write_name (d->cmi_name, fp, column, colmax);
403 fputs (":", fp)fputs_unlocked (":", fp);
404 column++;
405 make_write_vec (d->deps, fp, column, colmax);
406 fputs ("\n", fp)fputs_unlocked ("\n", fp);
407 if (CPP_OPTION (pfile, deps.phony_targets)((pfile)->opts.deps.phony_targets))
408 for (unsigned i = 1; i < d->deps.size (); i++)
409 fprintf (fp, "%s:\n", munge (d->deps[i]));
410 }
411
412 if (!CPP_OPTION (pfile, deps.modules)((pfile)->opts.deps.modules))
413 return;
414
415 if (d->modules.size ())
416 {
417 column = make_write_vec (d->targets, fp, 0, colmax, d->quote_lwm);
418 if (d->cmi_name)
419 column = make_write_name (d->cmi_name, fp, column, colmax);
420 fputs (":", fp)fputs_unlocked (":", fp);
421 column++;
422 column = make_write_vec (d->modules, fp, column, colmax, 0, ".c++m");
423 fputs ("\n", fp)fputs_unlocked ("\n", fp);
424 }
425
426 if (d->module_name)
427 {
428 if (d->cmi_name)
429 {
430 /* module-name : cmi-name */
431 column = make_write_name (d->module_name, fp, 0, colmax,
432 true, ".c++m");
433 fputs (":", fp)fputs_unlocked (":", fp);
434 column++;
435 column = make_write_name (d->cmi_name, fp, column, colmax);
436 fputs ("\n", fp)fputs_unlocked ("\n", fp);
437
438 column = fprintf (fp, ".PHONY:");
439 column = make_write_name (d->module_name, fp, column, colmax,
Value stored to 'column' is never read
440 true, ".c++m");
441 fputs ("\n", fp)fputs_unlocked ("\n", fp);
442 }
443
444 if (d->cmi_name && !d->is_header_unit)
445 {
446 /* An order-only dependency.
447 cmi-name :| first-target
448 We can probably drop this this in favour of Make-4.3's grouped
449 targets '&:' */
450 column = make_write_name (d->cmi_name, fp, 0, colmax);
451 fputs (":|", fp)fputs_unlocked (":|", fp);
452 column++;
453 column = make_write_name (d->targets[0], fp, column, colmax);
454 fputs ("\n", fp)fputs_unlocked ("\n", fp);
455 }
456 }
457
458 if (d->modules.size ())
459 {
460 column = fprintf (fp, "CXX_IMPORTS +=");
461 make_write_vec (d->modules, fp, column, colmax, 0, ".c++m");
462 fputs ("\n", fp)fputs_unlocked ("\n", fp);
463 }
464}
465
466/* Write out dependencies according to the selected format (which is
467 only Make at the moment). */
468/* Really we should be opening fp here. */
469
470void
471deps_write (const cpp_reader *pfile, FILE *fp, unsigned int colmax)
472{
473 make_write (pfile, fp, colmax);
474}
475
476/* Write out a deps buffer to a file, in a form that can be read back
477 with deps_restore. Returns nonzero on error, in which case the
478 error number will be in errno. */
479
480int
481deps_save (class mkdeps *deps, FILE *f)
482{
483 unsigned int i;
484 size_t size;
485
486 /* The cppreader structure contains makefile dependences. Write out this
487 structure. */
488
489 /* The number of dependences. */
490 size = deps->deps.size ();
491 if (fwrite (&size, sizeof (size), 1, f)fwrite_unlocked (&size, sizeof (size), 1, f) != 1)
492 return -1;
493
494 /* The length of each dependence followed by the string. */
495 for (i = 0; i < deps->deps.size (); i++)
496 {
497 size = strlen (deps->deps[i]);
498 if (fwrite (&size, sizeof (size), 1, f)fwrite_unlocked (&size, sizeof (size), 1, f) != 1)
499 return -1;
500 if (fwrite (deps->deps[i], size, 1, f)fwrite_unlocked (deps->deps[i], size, 1, f) != 1)
501 return -1;
502 }
503
504 return 0;
505}
506
507/* Read back dependency information written with deps_save into
508 the deps sizefer. The third argument may be NULL, in which case
509 the dependency information is just skipped, or it may be a filename,
510 in which case that filename is skipped. */
511
512int
513deps_restore (class mkdeps *deps, FILE *fd, const char *self)
514{
515 size_t size;
516 char *buf = NULL__null;
517 size_t buf_size = 0;
518
519 /* Number of dependences. */
520 if (fread (&size, sizeof (size), 1, fd)fread_unlocked (&size, sizeof (size), 1, fd) != 1)
521 return -1;
522
523 /* The length of each dependence string, followed by the string. */
524 for (unsigned i = size; i--;)
525 {
526 /* Read in # bytes in string. */
527 if (fread (&size, sizeof (size), 1, fd)fread_unlocked (&size, sizeof (size), 1, fd) != 1)
528 return -1;
529
530 if (size >= buf_size)
531 {
532 buf_size = size + 512;
533 buf = XRESIZEVEC (char, buf, buf_size)((char *) xrealloc ((void *) (buf), sizeof (char) * (buf_size
)))
;
534 }
535 if (fread (buf, 1, size, fd)fread_unlocked (buf, 1, size, fd) != size)
536 {
537 XDELETEVEC (buf)free ((void*) (buf));
538 return -1;
539 }
540 buf[size] = 0;
541
542 /* Generate makefile dependencies from .pch if -nopch-deps. */
543 if (self != NULL__null && filename_cmp (buf, self) != 0)
544 deps_add_dep (deps, buf);
545 }
546
547 XDELETEVEC (buf)free ((void*) (buf));
548 return 0;
549}