libcpp/mkdeps.c

   1 /* Dependency generator for Makefile fragments.
   2    Copyright (C) 2000-2020 Free Software Foundation, Inc.
   3    Contributed by Zack Weinberg, Mar 2000
   4
   5 This program is free software; you can redistribute it and/or modify it
   6 under the terms of the GNU General Public License as published by the
   7 Free Software Foundation; either version 3, or (at your option) any
   8 later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along 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
  27 /* Not set up to just include std::vector et al, here's a simple
  28    implementation.  */
  29
  30 /* Keep this structure local to this file, so clients don't find it
  31    easy to start making assumptions.  */
  32 class mkdeps
  33 {
  34 public:
  35   /* T has trivial cctor & dtor.  */
  36   template <typename T>
  37   class vec
  38   {
  39   private:
  40     T *ary;
  41     unsigned num;
  42     unsigned alloc;
  43
  44   public:
  45     vec ()
  46       : ary (NULL), num (0), alloc (0)
  47       {}
  48     ~vec ()
  49       {
  50         XDELETEVEC (ary);
  51       }
  52
  53   public:
  54     unsigned size () const
  55     {
  56       return num;
  57     }
  58     const T &operator[] (unsigned ix) const
  59     {
  60       return ary[ix];
  61     }
  62     T &operator[] (unsigned ix)
  63     {
  64       return ary[ix];
  65     }
  66     void push (const T &elt)
  67     {
  68       if (num == alloc)
  69         {
  70           alloc = alloc ? alloc * 2 : 16;
  71           ary = XRESIZEVEC (T, ary, alloc);
  72         }
  73       ary[num++] = elt;
  74     }
  75   };
  76   struct velt
  77   {
  78     const char *str;
  79     size_t len;
  80   };
  81
  82   mkdeps ()
  83     : quote_lwm (0)
  84   {
  85   }
  86   ~mkdeps ()
  87   {
  88     unsigned int i;
  89
  90     for (i = targets.size (); i--;)
  91       free (const_cast <char *> (targets[i]));
  92     for (i = deps.size (); i--;)
  93       free (const_cast <char *> (deps[i]));
  94     for (i = vpath.size (); i--;)
  95       XDELETEVEC (vpath[i].str);
  96   }
  97
  98 public:
  99   vec<const char *> targets;
 100   vec<const char *> deps;
 101   vec<velt> vpath;
 102
 103 public:
 104   unsigned short quote_lwm;
 105 };
 106
 107 /* Apply Make quoting to STR, TRAIL etc.  Note that it's not possible
 108    to quote all such characters - e.g. \n, %, *, ?, [, \ (in some
 109    contexts), and ~ are not properly handled.  It isn't possible to
 110    get this right in any current version of Make.  (??? Still true?
 111    Old comment referred to 3.76.1.)  */
 112
 113 static const char *
 114 munge (const char *str, const char *trail = NULL, ...)
 115 {
 116   static unsigned alloc;
 117   static char *buf;
 118   unsigned dst = 0;
 119   va_list args;
 120   if (trail)
 121     va_start (args, trail);
 122
 123   for (bool first = true; str; first = false)
 124     {
 125       unsigned slashes = 0;
 126       char c;
 127       for (const char *probe = str; (c = *probe++);)
 128         {
 129           if (alloc < dst + 4 + slashes)
 130             {
 131               alloc = alloc * 2 + 32;
 132               buf = XRESIZEVEC (char, buf, alloc);
 133             }
 134
 135           switch (c)
 136             {
 137             case '\\':
 138               slashes++;
 139               break;
 140
 141             case '$':
 142               buf[dst++] = '$';
 143               goto def;
 144
 145             case ' ':
 146             case '\t':
 147               /* GNU make uses a weird quoting scheme for white space.
 148                  A space or tab preceded by 2N+1 backslashes
 149                  represents N backslashes followed by space; a space
 150                  or tab preceded by 2N backslashes represents N
 151                  backslashes at the end of a file name; and
 152                  backslashes in other contexts should not be
 153                  doubled.  */
 154               while (slashes--)
 155                 buf[dst++] = '\\';
 156               /* FALLTHROUGH  */
 157
 158             case '#':
 159             case ':':
 160               buf[dst++] = '\\';
 161               /* FALLTHROUGH  */
 162
 163             default:
 164             def:
 165               slashes = 0;
 166               break;
 167             }
 168
 169           buf[dst++] = c;
 170         }
 171
 172       if (first)
 173         str = trail;
 174       else
 175         str = va_arg (args, const char *);
 176     }
 177   if (trail)
 178     va_end (args);
 179
 180   buf[dst] = 0;
 181   return buf;
 182 }
 183
 184 /* If T begins with any of the partial pathnames listed in d->vpathv,
 185    then advance T to point beyond that pathname.  */
 186 static const char *
 187 apply_vpath (class mkdeps *d, const char *t)
 188 {
 189   if (unsigned len = d->vpath.size ())
 190     for (unsigned i = len; i--;)
 191       {
 192         if (!filename_ncmp (d->vpath[i].str, t, d->vpath[i].len))
 193           {
 194             const char *p = t + d->vpath[i].len;
 195             if (!IS_DIR_SEPARATOR (*p))
 196               goto not_this_one;
 197
 198             /* Do not simplify $(vpath)/../whatever.  ??? Might not
 199                be necessary. */
 200             if (p[1] == '.' && p[2] == '.' && IS_DIR_SEPARATOR (p[3]))
 201               goto not_this_one;
 202
 203             /* found a match */
 204             t = t + d->vpath[i].len + 1;
 205             break;
 206           }
 207       not_this_one:;
 208       }
 209
 210   /* Remove leading ./ in any case.  */
 211   while (t[0] == '.' && IS_DIR_SEPARATOR (t[1]))
 212     {
 213       t += 2;
 214       /* If we removed a leading ./, then also remove any /s after the
 215          first.  */
 216       while (IS_DIR_SEPARATOR (t[0]))
 217         ++t;
 218     }
 219
 220   return t;
 221 }
 222
 223 /* Public routines.  */
 224
 225 class mkdeps *
 226 deps_init (void)
 227 {
 228   return new mkdeps ();
 229 }
 230
 231 void
 232 deps_free (class mkdeps *d)
 233 {
 234   delete d;
 235 }
 236
 237 /* Adds a target T.  We make a copy, so it need not be a permanent
 238    string.  QUOTE is true if the string should be quoted.  */
 239 void
 240 deps_add_target (class mkdeps *d, const char *t, int quote)
 241 {
 242   t = xstrdup (apply_vpath (d, t));
 243
 244   if (!quote)
 245     {
 246       /* Sometimes unquoted items are added after quoted ones.
 247          Swap out the lowest quoted.  */
 248       if (d->quote_lwm != d->targets.size ())
 249         {
 250           const char *lowest = d->targets[d->quote_lwm];
 251           d->targets[d->quote_lwm] = t;
 252           t = lowest;
 253         }
 254       d->quote_lwm++;
 255     }
 256
 257   d->targets.push (t);
 258 }
 259
 260 /* Sets the default target if none has been given already.  An empty
 261    string as the default target in interpreted as stdin.  The string
 262    is quoted for MAKE.  */
 263 void
 264 deps_add_default_target (class mkdeps *d, const char *tgt)
 265 {
 266   /* Only if we have no targets.  */
 267   if (d->targets.size ())
 268     return;
 269
 270   if (tgt[0] == '\0')
 271     deps_add_target (d, "-", 1);
 272   else
 273     {
 274 #ifndef TARGET_OBJECT_SUFFIX
 275 # define TARGET_OBJECT_SUFFIX ".o"
 276 #endif
 277       const char *start = lbasename (tgt);
 278       char *o = (char *) alloca (strlen (start)
 279                                  + strlen (TARGET_OBJECT_SUFFIX) + 1);
 280       char *suffix;
 281
 282       strcpy (o, start);
 283
 284       suffix = strrchr (o, '.');
 285       if (!suffix)
 286         suffix = o + strlen (o);
 287       strcpy (suffix, TARGET_OBJECT_SUFFIX);
 288
 289       deps_add_target (d, o, 1);
 290     }
 291 }
 292
 293 void
 294 deps_add_dep (class mkdeps *d, const char *t)
 295 {
 296   gcc_assert (*t);
 297
 298   t = apply_vpath (d, t);
 299
 300   d->deps.push (xstrdup (t));
 301 }
 302
 303 void
 304 deps_add_vpath (class mkdeps *d, const char *vpath)
 305 {
 306   const char *elem, *p;
 307
 308   for (elem = vpath; *elem; elem = p)
 309     {
 310       for (p = elem; *p && *p != ':'; p++)
 311         continue;
 312       mkdeps::velt elt;
 313       elt.len = p - elem;
 314       char *str = XNEWVEC (char, elt.len + 1);
 315       elt.str = str;
 316       memcpy (str, elem, elt.len);
 317       str[elt.len] = '\0';
 318       if (*p == ':')
 319         p++;
 320
 321       d->vpath.push (elt);
 322     }
 323 }
 324
 325 /* Write NAME, with a leading space to FP, a Makefile.  Advance COL as
 326    appropriate, wrap at COLMAX, returning new column number.  Iff
 327    QUOTE apply quoting.  Append TRAIL.  */
 328
 329 static unsigned
 330 make_write_name (const char *name, FILE *fp, unsigned col, unsigned colmax,
 331                  bool quote = true, const char *trail = NULL)
 332 {
 333   if (quote)
 334     name = munge (name, trail, NULL);
 335   unsigned size = strlen (name);
 336
 337   if (col)
 338     {
 339       if (colmax && col + size> colmax)
 340         {
 341           fputs (" \\\n", fp);
 342           col = 0;
 343         }
 344       col++;
 345       fputs (" ", fp);
 346     }
 347
 348   col += size;
 349   fputs (name, fp);
 350
 351   return col;
 352 }
 353
 354 /* Write all the names in VEC via make_write_name.  */
 355
 356 static unsigned
 357 make_write_vec (const mkdeps::vec<const char *> &vec, FILE *fp,
 358                 unsigned col, unsigned colmax, unsigned quote_lwm = 0,
 359                 const char *trail = NULL)
 360 {
 361   for (unsigned ix = 0; ix != vec.size (); ix++)
 362     col = make_write_name (vec[ix], fp, col, colmax, ix >= quote_lwm, trail);
 363   return col;
 364 }
 365
 366 /* Write the dependencies to a Makefile.  If PHONY is true, add
 367    .PHONY targets for all the dependencies too.  */
 368
 369 static void
 370 make_write (const class mkdeps *d, FILE *fp, bool phony, unsigned int colmax)
 371 {
 372   unsigned column = 0;
 373   if (colmax && colmax < 34)
 374     colmax = 34;
 375
 376   if (d->deps.size ())
 377     {
 378       column = make_write_vec (d->targets, fp, 0, colmax, d->quote_lwm);
 379       fputs (":", fp);
 380       column++;
 381       make_write_vec (d->deps, fp, column, colmax);
 382       fputs ("\n", fp);
 383       if (phony)
 384         for (unsigned i = 1; i < d->deps.size (); i++)
 385           fprintf (fp, "%s:\n", munge (d->deps[i]));
 386     }
 387 }
 388
 389 /* Write out dependencies according to the selected format (which is
 390    only Make at the moment).  */
 391
 392 void
 393 deps_write (const class mkdeps *d, FILE *fp, bool phony, unsigned int colmax)
 394 {
 395   make_write (d, fp, phony, colmax);
 396 }
 397
 398 /* Write out a deps buffer to a file, in a form that can be read back
 399    with deps_restore.  Returns nonzero on error, in which case the
 400    error number will be in errno.  */
 401
 402 int
 403 deps_save (class mkdeps *deps, FILE *f)
 404 {
 405   unsigned int i;
 406   size_t size;
 407
 408   /* The cppreader structure contains makefile dependences.  Write out this
 409      structure.  */
 410
 411   /* The number of dependences.  */
 412   size = deps->deps.size ();
 413   if (fwrite (&size, sizeof (size), 1, f) != 1)
 414     return -1;
 415
 416   /* The length of each dependence followed by the string.  */
 417   for (i = 0; i < deps->deps.size (); i++)
 418     {
 419       size = strlen (deps->deps[i]);
 420       if (fwrite (&size, sizeof (size), 1, f) != 1)
 421         return -1;
 422       if (fwrite (deps->deps[i], size, 1, f) != 1)
 423         return -1;
 424     }
 425
 426   return 0;
 427 }
 428
 429 /* Read back dependency information written with deps_save into
 430    the deps sizefer.  The third argument may be NULL, in which case
 431    the dependency information is just skipped, or it may be a filename,
 432    in which case that filename is skipped.  */
 433
 434 int
 435 deps_restore (class mkdeps *deps, FILE *fd, const char *self)
 436 {
 437   size_t size;
 438   char *buf = NULL;
 439   size_t buf_size = 0;
 440
 441   /* Number of dependences.  */
 442   if (fread (&size, sizeof (size), 1, fd) != 1)
 443     return -1;
 444
 445   /* The length of each dependence string, followed by the string.  */
 446   for (unsigned i = size; i--;)
 447     {
 448       /* Read in # bytes in string.  */
 449       if (fread (&size, sizeof (size), 1, fd) != 1)
 450         return -1;
 451
 452       if (size >= buf_size)
 453         {
 454           buf_size = size + 512;
 455           buf = XRESIZEVEC (char, buf, buf_size);
 456         }
 457       if (fread (buf, 1, size, fd) != size)
 458         {
 459           XDELETEVEC (buf);
 460           return -1;
 461         }
 462       buf[size] = 0;
 463
 464       /* Generate makefile dependencies from .pch if -nopch-deps.  */
 465       if (self != NULL && filename_cmp (buf, self) != 0)
 466         deps_add_dep (deps, buf);
 467     }
 468
 469   XDELETEVEC (buf);
 470   return 0;
 471 }