libcpp/mkdeps.cc

   1 /* Dependency generator for Makefile fragments.
   2    Copyright (C) 2000-2022 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 #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.  */
  33 class mkdeps
  34 {
  35 public:
  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), num (0), alloc (0)
  48       {}
  49     ~vec ()
  50       {
  51         XDELETEVEC (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);
  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), cmi_name (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);
  97     for (i = modules.size (); i--;)
  98       XDELETEVEC (modules[i]);
  99     XDELETEVEC (module_name);
 100     free (const_cast <char *> (cmi_name));
 101   }
 102
 103 public:
 104   vec<const char *> targets;
 105   vec<const char *> deps;
 106   vec<velt> vpath;
 107   vec<const char *> modules;
 108
 109 public:
 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
 122 static const char *
 123 munge (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);
 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.  */
 184 static const char *
 185 apply_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))
 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]))
 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]))
 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]))
 215         ++t;
 216     }
 217
 218   return t;
 219 }
 220
 221 /* Public routines.  */
 222
 223 class mkdeps *
 224 deps_init (void)
 225 {
 226   return new mkdeps ();
 227 }
 228
 229 void
 230 deps_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.  */
 237 void
 238 deps_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.  */
 261 void
 262 deps_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
 273 # define TARGET_OBJECT_SUFFIX ".o"
 274 #endif
 275       const char *start = lbasename (tgt);
 276       char *o = (char *) alloca (strlen (start)
 277                                  + strlen (TARGET_OBJECT_SUFFIX) + 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);
 286
 287       deps_add_target (d, o, 1);
 288     }
 289 }
 290
 291 void
 292 deps_add_dep (class mkdeps *d, const char *t)
 293 {
 294   gcc_assert (*t);
 295
 296   t = apply_vpath (d, t);
 297
 298   d->deps.push (xstrdup (t));
 299 }
 300
 301 void
 302 deps_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);
 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
 326 void
 327 deps_add_module_target (struct mkdeps *d, const char *m,
 328                         const char *cmi, bool is_header_unit)
 329 {
 330   gcc_assert (!d->module_name);
 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
 339 void
 340 deps_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
 349 static unsigned
 350 make_write_name (const char *name, FILE *fp, unsigned col, unsigned colmax,
 351                  bool quote = true, const char *trail = 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);
 362           col = 0;
 363         }
 364       col++;
 365       fputs (" ", fp);
 366     }
 367
 368   col += size;
 369   fputs (name, fp);
 370
 371   return col;
 372 }
 373
 374 /* Write all the names in VEC via make_write_name.  */
 375
 376 static unsigned
 377 make_write_vec (const mkdeps::vec<const char *> &vec, FILE *fp,
 378                 unsigned col, unsigned colmax, unsigned quote_lwm = 0,
 379                 const char *trail = 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
 389 static void
 390 make_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) && d->cmi_name)
 402         column = make_write_name (d->cmi_name, fp, column, colmax);
 403       fputs (":", fp);
 404       column++;
 405       make_write_vec (d->deps, fp, column, colmax);
 406       fputs ("\n", fp);
 407       if (CPP_OPTION (pfile, 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))
 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);
 421       column++;
 422       column = make_write_vec (d->modules, fp, column, colmax, 0, ".c++m");
 423       fputs ("\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);
 434           column++;
 435           column = make_write_name (d->cmi_name, fp, column, colmax);
 436           fputs ("\n", fp);
 437
 438           column = fprintf (fp, ".PHONY:");
 439           column = make_write_name (d->module_name, fp, column, colmax,
 440                                     true, ".c++m");
 441           fputs ("\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);
 452           column++;
 453           column = make_write_name (d->targets[0], fp, column, colmax);
 454           fputs ("\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);
 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
 470 void
 471 deps_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
 480 int
 481 deps_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) != 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) != 1)
 499         return -1;
 500       if (fwrite (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
 512 int
 513 deps_restore (class mkdeps *deps, FILE *fd, const char *self)
 514 {
 515   size_t size;
 516   char *buf = NULL;
 517   size_t buf_size = 0;
 518
 519   /* Number of dependences.  */
 520   if (fread (&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) != 1)
 528         return -1;
 529
 530       if (size >= buf_size)
 531         {
 532           buf_size = size + 512;
 533           buf = XRESIZEVEC (char, buf, buf_size);
 534         }
 535       if (fread (buf, 1, size, fd) != size)
 536         {
 537           XDELETEVEC (buf);
 538           return -1;
 539         }
 540       buf[size] = 0;
 541
 542       /* Generate makefile dependencies from .pch if -nopch-deps.  */
 543       if (self != NULL && filename_cmp (buf, self) != 0)
 544         deps_add_dep (deps, buf);
 545     }
 546
 547   XDELETEVEC (buf);
 548   return 0;
 549 }