/* Pattern and suffix rule internals for GNU Make.

Copyright (C) 1988-2016 Free Software Foundation, Inc.

This file is part of GNU Make.

GNU Make is free software; you can redistribute it and/or modify it under the

terms of the GNU General Public License as published by the Free Software

Foundation; either version 3 of the License, or (at your option) any later

version.

GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY

WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR

A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with

this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "makeint.h"

#include <assert.h>

#include "filedef.h"

#include "dep.h"

#include "job.h"

#include "commands.h"

#include "variable.h"

#include "rule.h"

static void freerule (struct rule *rule, struct rule *lastrule);

/* Chain of all pattern rules.  */

struct rule *pattern_rules;

/* Pointer to last rule in the chain, so we can add onto the end.  */

struct rule *last_pattern_rule;

/* Number of rules in the chain.  */

unsigned int num_pattern_rules;

/* Maximum number of target patterns of any pattern rule.  */

unsigned int max_pattern_targets;

/* Maximum number of dependencies of any pattern rule.  */

unsigned int max_pattern_deps;

/* Maximum length of the name of a dependencies of any pattern rule.  */

unsigned int max_pattern_dep_length;

/* Pointer to structure for the file .SUFFIXES

   whose dependencies are the suffixes to be searched.  */

struct file *suffix_file;

/* Maximum length of a suffix.  */

unsigned int maxsuffix;

/* Compute the maximum dependency length and maximum number of

   dependencies of all implicit rules.  Also sets the subdir

   flag for a rule when appropriate, possibly removing the rule

   completely when appropriate.  */

void

count_implicit_rule_limits (void)

{

  char *name;

  int namelen;

  struct rule *rule;

  num_pattern_rules = max_pattern_targets = max_pattern_deps = 0;

  max_pattern_dep_length = 0;

  name = 0;

  namelen = 0;

  rule = pattern_rules;

  while (rule != 0)

    {

      unsigned int ndeps = 0;

      struct dep *dep;

      struct rule *next = rule->next;

      ++num_pattern_rules;

      if (rule->num > max_pattern_targets)

        max_pattern_targets = rule->num;

      for (dep = rule->deps; dep != 0; dep = dep->next)

        {

          const char *dname = dep_name (dep);

          unsigned int len = strlen (dname);

#ifdef VMS

          const char *p = strrchr (dname, ']');

          const char *p2;

          if (p == 0)

            p = strrchr (dname, ':');

          p2 = p != 0 ? strchr (dname, '%') : 0;

#else

          const char *p = strrchr (dname, '/');

          const char *p2 = p != 0 ? strchr (dname, '%') : 0;

#endif

          ndeps++;

          if (len > max_pattern_dep_length)

            max_pattern_dep_length = len;

          if (p != 0 && p2 > p)

            {

              /* There is a slash before the % in the dep name.

                 Extract the directory name.  */

              if (p == dname)

                ++p;

              if (p - dname > namelen)

                {

                  namelen = p - dname;

                  name = xrealloc (name, namelen + 1);

                }

              memcpy (name, dname, p - dname);

              name[p - dname] = '\0';

              /* In the deps of an implicit rule the 'changed' flag

                 actually indicates that the dependency is in a

                 nonexistent subdirectory.  */

              dep->changed = !dir_file_exists_p (name, "");

            }

          else

            /* This dependency does not reside in a subdirectory.  */

            dep->changed = 0;

        }

      if (ndeps > max_pattern_deps)

        max_pattern_deps = ndeps;

      rule = next;

    }

  free (name);

}

/* Create a pattern rule from a suffix rule.

   TARGET is the target suffix; SOURCE is the source suffix.

   CMDS are the commands.

   If TARGET is nil, it means the target pattern should be '(%.o)'.

   If SOURCE is nil, it means there should be no deps.  */

static void

convert_suffix_rule (const char *target, const char *source,

                     struct commands *cmds)

{

  const char **names, **percents;

  struct dep *deps;

  names = xmalloc (sizeof (const char *));

  percents = xmalloc (sizeof (const char *));

  if (target == 0)

    {

      /* Special case: TARGET being nil means we are defining a '.X.a' suffix

         rule; the target pattern is always '(%.o)'.  */

#ifdef VMS

      *names = strcache_add_len ("(%.obj)", 7);

#else

      *names = strcache_add_len ("(%.o)", 5);

#endif

      *percents = *names + 1;

    }

  else

    {

      /* Construct the target name.  */

      unsigned int len = strlen (target);

      char *p = alloca (1 + len + 1);

      p[0] = '%';

      memcpy (p + 1, target, len + 1);

      *names = strcache_add_len (p, len + 1);

      *percents = *names;

    }

  if (source == 0)

    deps = 0;

  else

    {

      /* Construct the dependency name.  */

      unsigned int len = strlen (source);

      char *p = alloca (1 + len + 1);

      p[0] = '%';

      memcpy (p + 1, source, len + 1);

      deps = alloc_dep ();

      deps->name = strcache_add_len (p, len + 1);

    }

  create_pattern_rule (names, percents, 1, 0, deps, cmds, 0);

}

/* Convert old-style suffix rules to pattern rules.

   All rules for the suffixes on the .SUFFIXES list are converted and added to

   the chain of pattern rules.  */

void

convert_to_pattern (void)

{

  struct dep *d, *d2;

  char *rulename;

  /* We will compute every potential suffix rule (.x.y) from the list of

     suffixes in the .SUFFIXES target's dependencies and see if it exists.

     First find the longest of the suffixes.  */

  maxsuffix = 0;

  for (d = suffix_file->deps; d != 0; d = d->next)

    {

      unsigned int l = strlen (dep_name (d));

      if (l > maxsuffix)

        maxsuffix = l;

    }

  /* Space to construct the suffix rule target name.  */

  rulename = alloca ((maxsuffix * 2) + 1);

  for (d = suffix_file->deps; d != 0; d = d->next)

    {

      unsigned int slen;

      /* Make a rule that is just the suffix, with no deps or commands.

         This rule exists solely to disqualify match-anything rules.  */

      convert_suffix_rule (dep_name (d), 0, 0);

      if (d->file->cmds != 0)

        /* Record a pattern for this suffix's null-suffix rule.  */

        convert_suffix_rule ("", dep_name (d), d->file->cmds);

      /* Add every other suffix to this one and see if it exists as a

         two-suffix rule.  */

      slen = strlen (dep_name (d));

      memcpy (rulename, dep_name (d), slen);

      for (d2 = suffix_file->deps; d2 != 0; d2 = d2->next)

        {

          struct file *f;

          unsigned int s2len;

          s2len = strlen (dep_name (d2));

          /* Can't build something from itself.  */

          if (slen == s2len && streq (dep_name (d), dep_name (d2)))

            continue;

          memcpy (rulename + slen, dep_name (d2), s2len + 1);

          f = lookup_file (rulename);

          if (f == 0 || f->cmds == 0)

            continue;

          if (s2len == 2 && rulename[slen] == '.' && rulename[slen + 1] == 'a')

            /* A suffix rule '.X.a:' generates the pattern rule '(%.o): %.X'.

               It also generates a normal '%.a: %.X' rule below.  */

            convert_suffix_rule (NULL, /* Indicates '(%.o)'.  */

                                 dep_name (d),

                                 f->cmds);

          /* The suffix rule '.X.Y:' is converted

             to the pattern rule '%.Y: %.X'.  */

          convert_suffix_rule (dep_name (d2), dep_name (d), f->cmds);

        }

    }

}

/* Install the pattern rule RULE (whose fields have been filled in) at the end

   of the list (so that any rules previously defined will take precedence).

   If this rule duplicates a previous one (identical target and dependencies),

   the old one is replaced if OVERRIDE is nonzero, otherwise this new one is

   thrown out.  When an old rule is replaced, the new one is put at the end of

   the list.  Return nonzero if RULE is used; zero if not.  */

static int

new_pattern_rule (struct rule *rule, int override)

{

  struct rule *r, *lastrule;

  unsigned int i, j;

  rule->in_use = 0;

  rule->terminal = 0;

  rule->next = 0;

  /* Search for an identical rule.  */

  lastrule = 0;

  for (r = pattern_rules; r != 0; lastrule = r, r = r->next)

    for (i = 0; i < rule->num; ++i)

      {

        for (j = 0; j < r->num; ++j)

          if (!streq (rule->targets[i], r->targets[j]))

            break;

        /* If all the targets matched...  */

        if (j == r->num)

          {

            struct dep *d, *d2;

            for (d = rule->deps, d2 = r->deps;

                 d != 0 && d2 != 0; d = d->next, d2 = d2->next)

              if (!streq (dep_name (d), dep_name (d2)))

                break;

            if (d == 0 && d2 == 0)

              {

                /* All the dependencies matched.  */

                if (override)

                  {

                    /* Remove the old rule.  */

                    freerule (r, lastrule);

                    /* Install the new one.  */

                    if (pattern_rules == 0)

                      pattern_rules = rule;

                    else

                      last_pattern_rule->next = rule;

                    last_pattern_rule = rule;

                    /* We got one.  Stop looking.  */

                    goto matched;

                  }

                else

                  {

                    /* The old rule stays intact.  Destroy the new one.  */

                    freerule (rule, (struct rule *) 0);

                    return 0;

                  }

              }

          }

      }

 matched:;

  if (r == 0)

    {

      /* There was no rule to replace.  */

      if (pattern_rules == 0)

        pattern_rules = rule;

      else

        last_pattern_rule->next = rule;

      last_pattern_rule = rule;

    }

  return 1;

}

/* Install an implicit pattern rule based on the three text strings

   in the structure P points to.  These strings come from one of

   the arrays of default implicit pattern rules.

   TERMINAL specifies what the 'terminal' field of the rule should be.  */

void

install_pattern_rule (struct pspec *p, int terminal)

{

  struct rule *r;

  const char *ptr;

  r = xmalloc (sizeof (struct rule));

  r->num = 1;

  r->targets = xmalloc (sizeof (const char *));

  r->suffixes = xmalloc (sizeof (const char *));

  r->lens = xmalloc (sizeof (unsigned int));

  r->lens[0] = strlen (p->target);

  r->targets[0] = p->target;

  r->suffixes[0] = find_percent_cached (&r->targets[0]);

  assert (r->suffixes[0] != NULL);

  ++r->suffixes[0];

  ptr = p->dep;

  r->deps = PARSE_SIMPLE_SEQ ((char **)&ptr, struct dep);

  if (new_pattern_rule (r, 0))

    {

      r->terminal = terminal;

      r->cmds = xmalloc (sizeof (struct commands));

      r->cmds->fileinfo.filenm = 0;

      r->cmds->fileinfo.lineno = 0;

      r->cmds->fileinfo.offset = 0;

      /* These will all be string literals, but we malloc space for them

         anyway because somebody might want to free them later.  */

      r->cmds->commands = xstrdup (p->commands);

      r->cmds->command_lines = 0;

      r->cmds->recipe_prefix = RECIPEPREFIX_DEFAULT;

    }

}

/* Free all the storage used in RULE and take it out of the

   pattern_rules chain.  LASTRULE is the rule whose next pointer

   points to RULE.  */

static void

freerule (struct rule *rule, struct rule *lastrule)

{

  struct rule *next = rule->next;

  free_dep_chain (rule->deps);

  /* MSVC erroneously warns without a cast here.  */

  free ((void *)rule->targets);

  free ((void *)rule->suffixes);

  free (rule->lens);

  /* We can't free the storage for the commands because there

     are ways that they could be in more than one place:

       * If the commands came from a suffix rule, they could also be in

       the 'struct file's for other suffix rules or plain targets given

       on the same makefile line.

       * If two suffixes that together make a two-suffix rule were each

       given twice in the .SUFFIXES list, and in the proper order, two

       identical pattern rules would be created and the second one would

       be discarded here, but both would contain the same 'struct commands'

       pointer from the 'struct file' for the suffix rule.  */

  free (rule);

  if (pattern_rules == rule)

    if (lastrule != 0)

      abort ();

    else

      pattern_rules = next;

  else if (lastrule != 0)

    lastrule->next = next;

  if (last_pattern_rule == rule)

    last_pattern_rule = lastrule;

}

/* Create a new pattern rule with the targets in the nil-terminated array

   TARGETS.  TARGET_PERCENTS is an array of pointers to the % in each element

   of TARGETS.  N is the number of items in the array (not counting the nil

   element).  The new rule has dependencies DEPS and commands from COMMANDS.

   It is a terminal rule if TERMINAL is nonzero.  This rule overrides

   identical rules with different commands if OVERRIDE is nonzero.

   The storage for TARGETS and its elements and TARGET_PERCENTS is used and

   must not be freed until the rule is destroyed.  */

void

create_pattern_rule (const char **targets, const char **target_percents,

                     unsigned int n, int terminal, struct dep *deps,

                     struct commands *commands, int override)

{

  unsigned int i;

  struct rule *r = xmalloc (sizeof (struct rule));

  r->num = n;

  r->cmds = commands;

  r->deps = deps;

  r->targets = targets;

  r->suffixes = target_percents;

  r->lens = xmalloc (n * sizeof (unsigned int));

  for (i = 0; i < n; ++i)

    {

      r->lens[i] = strlen (targets[i]);

      assert (r->suffixes[i] != NULL);

      ++r->suffixes[i];

    }

  if (new_pattern_rule (r, override))

    r->terminal = terminal;

}

/* Print the data base of rules.  */

static void                     /* Useful to call from gdb.  */

print_rule (struct rule *r)

{

  unsigned int i;

  for (i = 0; i < r->num; ++i)

    {

      fputs (r->targets[i], stdout);

      putchar ((i + 1 == r->num) ? ':' : ' ');

    }

  if (r->terminal)

    putchar (':');

  print_prereqs (r->deps);

  if (r->cmds != 0)

    print_commands (r->cmds);

}

void

print_rule_data_base (void)

{

  unsigned int rules, terminal;

  struct rule *r;

  puts (_("\n# Implicit Rules"));

  rules = terminal = 0;

  for (r = pattern_rules; r != 0; r = r->next)

    {

      ++rules;

      putchar ('\n');

      print_rule (r);

      if (r->terminal)

        ++terminal;

    }

  if (rules == 0)

    puts (_("\n# No implicit rules."));

  else

    {

      printf (_("\n# %u implicit rules, %u"), rules, terminal);

#ifndef NO_FLOAT

      printf (" (%.1f%%)", (double) terminal / (double) rules * 100.0);

#else

      {

        int f = (terminal * 1000 + 5) / rules;

        printf (" (%d.%d%%)", f/10, f%10);

      }

#endif

      puts (_(" terminal."));

    }

  if (num_pattern_rules != rules)

    {

      /* This can happen if a fatal error was detected while reading the

         makefiles and thus count_implicit_rule_limits wasn't called yet.  */

      if (num_pattern_rules != 0)

        ONN (fatal, NILF, _("BUG: num_pattern_rules is wrong!  %u != %u"),

             num_pattern_rules, rules);

    }

}