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[make.git] / variable.c

/* Internals of variables for GNU Make.
Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993 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 2, 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 GNU Make; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "make.h"
#include "commands.h"
#include "variable.h"
#include "dep.h"
#include "file.h"

/* Hash table of all global variable definitions.  */

#ifndef VARIABLE_BUCKETS
#define VARIABLE_BUCKETS                523
#endif
#ifndef PERFILE_VARIABLE_BUCKETS
#define PERFILE_VARIABLE_BUCKETS        23
#endif
#ifndef SMALL_SCOPE_VARIABLE_BUCKETS
#define SMALL_SCOPE_VARIABLE_BUCKETS    13
#endif
static struct variable *variable_table[VARIABLE_BUCKETS];
static struct variable_set global_variable_set
  = { variable_table, VARIABLE_BUCKETS };
static struct variable_set_list global_setlist
  = { 0, &global_variable_set };
struct variable_set_list *current_variable_set_list = &global_setlist;
\f
/* Implement variables.  */

/* Define variable named NAME with value VALUE in SET.  VALUE is copied.
   LENGTH is the length of NAME, which does not need to be null-terminated.
   ORIGIN specifies the origin of the variable (makefile, command line
   or environment).
   If RECURSIVE is nonzero a flag is set in the variable saying
   that it should be recursively re-expanded.  */

static struct variable *
define_variable_in_set (name, length, value, origin, recursive, set)
     char *name;
     unsigned int length;
     char *value;
     enum variable_origin origin;
     int recursive;
     struct variable_set *set;
{
  register unsigned int i;
  register unsigned int hashval;
  register struct variable *v;

  hashval = 0;
  for (i = 0; i < length; ++i)
    HASH (hashval, name[i]);
  hashval %= set->buckets;

  for (v = set->table[hashval]; v != 0; v = v->next)
    if (*v->name == *name
        && !strncmp (v->name + 1, name + 1, length - 1)
        && v->name[length] == '\0')
      break;

  if (env_overrides && origin == o_env)
    origin = o_env_override;

  if (v != 0)
    {
      if (env_overrides && v->origin == o_env)
        /* V came from in the environment.  Since it was defined
           before the switches were parsed, it wasn't affected by -e.  */
        v->origin = o_env_override;

      /* A variable of this name is already defined.
         If the old definition is from a stronger source
         than this one, don't redefine it.  */
      if ((int) origin >= (int) v->origin)
        {
          if (v->value != 0)
            free (v->value);
          v->value = savestring (value, strlen (value));
          v->origin = origin;
          v->recursive = recursive;
        }
      return v;
    }

  /* Create a new variable definition and add it to the hash table.  */

  v = (struct variable *) xmalloc (sizeof (struct variable));
  v->name = savestring (name, length);
  v->value = savestring (value, strlen (value));
  v->origin = origin;
  v->recursive = recursive;
  v->expanding = 0;
  v->export = v_default;
  v->next = set->table[hashval];
  set->table[hashval] = v;
  return v;
}

/* Define a variable in the current variable set.  */

struct variable *
define_variable (name, length, value, origin, recursive)
     char *name;
     unsigned int length;
     char *value;
     enum variable_origin origin;
     int recursive;
{
  return define_variable_in_set (name, length, value, origin, recursive,
                                 current_variable_set_list->set);
}

/* Define a variable in FILE's variable set.  */

struct variable *
define_variable_for_file (name, length, value, origin, recursive, file)
     char *name;
     unsigned int length;
     char *value;
     enum variable_origin origin;
     int recursive;
     struct file *file;
{
  return define_variable_in_set (name, length, value, origin, recursive,
                                 file->variables->set);
}
\f
/* Lookup a variable whose name is a string starting at NAME
   and with LENGTH chars.  NAME need not be null-terminated.
   Returns address of the `struct variable' containing all info
   on the variable, or nil if no such variable is defined.  */

struct variable *
lookup_variable (name, length)
     char *name;
     unsigned int length;
{
  register struct variable_set_list *setlist;

  register unsigned int i;
  register unsigned int rawhash = 0;

  for (i = 0; i < length; ++i)
    HASH (rawhash, name[i]);

  for (setlist = current_variable_set_list;
       setlist != 0; setlist = setlist->next)
    {
      register struct variable_set *set = setlist->set;
      register unsigned int hashval = rawhash % set->buckets;
      register struct variable *v;

      for (v = set->table[hashval]; v != 0; v = v->next)
        if (*v->name == *name
            && !strncmp (v->name + 1, name + 1, length - 1)
            && v->name[length] == 0)
          return v;
    }

  return 0;
}
\f
/* Initialize FILE's variable set list.  If FILE already has a variable set
   list, the topmost variable set is left intact, but the the rest of the
   chain is replaced with FILE->parent's setlist.  */

void
initialize_file_variables (file)
     struct file *file;
{
  register struct variable_set_list *l = file->variables;
  if (l == 0)
    {
      l = (struct variable_set_list *)
        xmalloc (sizeof (struct variable_set_list));
      l->set = (struct variable_set *) xmalloc (sizeof (struct variable_set));
      l->set->buckets = PERFILE_VARIABLE_BUCKETS;
      l->set->table = (struct variable **)
        xmalloc (l->set->buckets * sizeof (struct variable *));
      bzero ((char *) l->set->table,
             l->set->buckets * sizeof (struct variable *));
      file->variables = l;
    }

  if (file->parent == 0)
    l->next = &global_setlist;
  else
    {
      if (file->parent->variables == 0)
        initialize_file_variables (file->parent);
      l->next = file->parent->variables;
    }
}
\f
/* Pop the top set off the current variable set list,
   and free all its storage.  */

void
pop_variable_scope ()
{
  register struct variable_set_list *setlist = current_variable_set_list;
  register struct variable_set *set = setlist->set;
  register unsigned int i;

  current_variable_set_list = setlist->next;
  free ((char *) setlist);

  for (i = 0; i < set->buckets; ++i)
    {
      register struct variable *next = set->table[i];
      while (next != 0)
        {
          register struct variable *v = next;
          next = v->next;

          free (v->name);
          free ((char *) v);
        }
    }
  free ((char *) set->table);
  free ((char *) set);
}

/* Create a new variable set and push it on the current setlist.  */

void
push_new_variable_scope ()
{
  register struct variable_set_list *setlist;
  register struct variable_set *set;

  set = (struct variable_set *) xmalloc (sizeof (struct variable_set));
  set->buckets = SMALL_SCOPE_VARIABLE_BUCKETS;
  set->table = (struct variable **)
    xmalloc (set->buckets * sizeof (struct variable *));
  bzero ((char *) set->table, set->buckets * sizeof (struct variable *));

  setlist = (struct variable_set_list *)
    xmalloc (sizeof (struct variable_set_list));
  setlist->set = set;
  setlist->next = current_variable_set_list;
  current_variable_set_list = setlist;
}
\f
/* Merge SET1 into SET0, freeing unused storage in SET1.  */

static void
merge_variable_sets (set0, set1)
     struct variable_set *set0, *set1;
{
  register unsigned int bucket1;

  for (bucket1 = 0; bucket1 < set1->buckets; ++bucket1)
    {
      register struct variable *v1 = set1->table[bucket1];
      while (v1 != 0)
        {
          struct variable *next = v1->next;
          unsigned int bucket0;
          register struct variable *v0;

          if (set1->buckets >= set0->buckets)
            bucket0 = bucket1;
          else
            {
              register char *n;
              bucket0 = 0;
              for (n = v1->name; *n != '\0'; ++n)
                HASH (bucket0, *n);
            }
          bucket0 %= set0->buckets;

          for (v0 = set0->table[bucket0]; v0 != 0; v0 = v0->next)
            if (streq (v0->name, v1->name))
              break;

          if (v0 == 0)
            {
              /* There is no variable in SET0 with the same name.  */
              v1->next = set0->table[bucket0];
              set0->table[bucket0] = v1;
            }
          else
            {
              /* The same variable exists in both sets.
                 SET0 takes precedence.  */
              free (v1->value);
              free ((char *) v1);
            }

          v1 = next;
        }
    }
}

/* Merge SETLIST1 into SETLIST0, freeing unused storage in SETLIST1.  */

void
merge_variable_set_lists (setlist0, setlist1)
     struct variable_set_list **setlist0, *setlist1;
{
  register struct variable_set_list *list0 = *setlist0;
  struct variable_set_list *last0 = 0;

  while (setlist1 != 0 && list0 != 0)
    {
      struct variable_set_list *next = setlist1;
      setlist1 = setlist1->next;

      merge_variable_sets (list0->set, next->set);

      free ((char *) next);

      last0 = list0;
      list0 = list0->next;
    }

  if (setlist1 != 0)
    {
      if (last0 == 0)
        *setlist0 = setlist1;
      else
        last0->next = setlist1;
    }
}
\f
/* Define the automatic variables, and record the addresses
   of their structures so we can change their values quickly.  */

void
define_automatic_variables ()
{
  extern char default_shell[];
  register struct variable *v;
  char buf[100];

  sprintf (buf, "%u", makelevel);
  (void) define_variable ("MAKELEVEL", 9, buf, o_env, 0);

  /* This won't override any definition, but it
     will provide one if there isn't one there.  */
  v = define_variable ("SHELL", 5, default_shell, o_default, 0);
  v->export = v_export;         /* Always export SHELL.  */

  /* Don't let SHELL come from the environment.  */
  if (*v->value == '\0' || v->origin == o_env || v->origin == o_env_override)
    {
      free (v->value);
      v->origin = o_file;
      v->value = savestring (default_shell, strlen (default_shell));
    }

  /* Make sure MAKEFILES gets exported if it is set.  */
  v = define_variable ("MAKEFILES", 9, "", o_default, 0);
  v->export = v_ifset;

  /* Define the magic D and F variables in terms of
     the automatic variables they are variations of.  */

  define_variable ("@D", 2, "$(dir $@)", o_automatic, 1);
  define_variable ("%D", 2, "$(dir $%)", o_automatic, 1);
  define_variable ("*D", 2, "$(dir $*)", o_automatic, 1);
  define_variable ("<D", 2, "$(dir $<)", o_automatic, 1);
  define_variable ("?D", 2, "$(dir $?)", o_automatic, 1);
  define_variable ("^D", 2, "$(dir $^)", o_automatic, 1);
  define_variable ("@F", 2, "$(notdir $@)", o_automatic, 1);
  define_variable ("%F", 2, "$(notdir $%)", o_automatic, 1);
  define_variable ("*F", 2, "$(notdir $*)", o_automatic, 1);
  define_variable ("<F", 2, "$(notdir $<)", o_automatic, 1);
  define_variable ("?F", 2, "$(notdir $?)", o_automatic, 1);
  define_variable ("^F", 2, "$(notdir $^)", o_automatic, 1);
}
\f
int export_all_variables;

/* Create a new environment for FILE's commands.
   If FILE is nil, this is for the `shell' function.
   The child's MAKELEVEL variable is incremented.  */

char **
target_environment (file)
     struct file *file;
{
  struct variable_set_list *set_list;
  register struct variable_set_list *s;
  struct variable_bucket
    {
      struct variable_bucket *next;
      struct variable *variable;
    };
  struct variable_bucket **table;
  unsigned int buckets;
  register unsigned int i;
  register unsigned nvariables;
  char **result;
  unsigned int mklev_hash;

  if (file == 0)
    set_list = current_variable_set_list;
  else
    set_list = file->variables;

  /* Find the lowest number of buckets in any set in the list.  */
  s = set_list;
  buckets = s->set->buckets;
  for (s = s->next; s != 0; s = s->next)
    if (s->set->buckets < buckets)
      buckets = s->set->buckets;

  /* Find the hash value of the bucket `MAKELEVEL' will fall into.  */
  {
    char *p = "MAKELEVEL";
    mklev_hash = 0;
    while (*p != '\0')
      HASH (mklev_hash, *p++);
  }

  /* Temporarily allocate a table with that many buckets.  */
  table = (struct variable_bucket **)
    alloca (buckets * sizeof (struct variable_bucket *));
  bzero ((char *) table, buckets * sizeof (struct variable_bucket *));

  /* Run through all the variable sets in the list,
     accumulating variables in TABLE.  */
  nvariables = 0;
  for (s = set_list; s != 0; s = s->next)
    {
      register struct variable_set *set = s->set;
      for (i = 0; i < set->buckets; ++i)
        {
          register struct variable *v;
          for (v = set->table[i]; v != 0; v = v->next)
            {
              unsigned int j = i % buckets;
              register struct variable_bucket *ov;
              register char *p = v->name;

              if (i == mklev_hash % set->buckets
                  && streq (v->name, "MAKELEVEL"))
                /* Don't include MAKELEVEL because it will be
                   added specially at the end.  */
                continue;

              switch (v->export)
                {
                case v_default:
                  if (v->origin == o_default || v->origin == o_automatic)
                    /* Only export default variables by explicit request.  */
                    continue;

                  if (! export_all_variables
                      && v->origin != o_command
                      && v->origin != o_env && v->origin != o_env_override)
                    continue;

                  if (*p != '_' && (*p < 'A' || *p > 'Z')
                      && (*p < 'a' || *p > 'z'))
                    continue;
                  for (++p; *p != '\0'; ++p)
                    if (*p != '_' && (*p < 'a' || *p > 'z')
                        && (*p < 'A' || *p > 'Z') && (*p < '0' || *p > '9'))
                      break;
                  if (*p != '\0')
                    continue;

                case v_export:
                  break;

                case v_noexport:
                  continue;

                case v_ifset:
                  if (v->origin == o_default)
                    continue;
                  break;
                }

              for (ov = table[j]; ov != 0; ov = ov->next)
                if (streq (v->name, ov->variable->name))
                  break;
              if (ov == 0)
                {
                  register struct variable_bucket *entry;
                  entry = (struct variable_bucket *)
                    alloca (sizeof (struct variable_bucket));
                  entry->next = table[j];
                  entry->variable = v;
                  table[j] = entry;
                  ++nvariables;
                }
            }
        }
    }

  result = (char **) xmalloc ((nvariables + 2) * sizeof (char *));
  nvariables = 0;
  for (i = 0; i < buckets; ++i)
    {
      register struct variable_bucket *b;
      for (b = table[i]; b != 0; b = b->next)
        {
          register struct variable *v = b->variable;
          /* If V is recursively expanded and didn't come from the environment,
             expand its value.  If it came from the environment, it should
             go back into the environment unchanged.  */
          if (v->recursive
              && v->origin != o_env && v->origin != o_env_override)
            {
              char *value = recursively_expand (v);
              result[nvariables++] = concat (v->name, "=", value);
              free (value);
            }
          else
            result[nvariables++] = concat (v->name, "=", v->value);
        }
    }
  result[nvariables] = (char *) xmalloc (100);
  (void) sprintf (result[nvariables], "MAKELEVEL=%u", makelevel + 1);
  result[++nvariables] = 0;

  return result;
}
\f
/* Try to interpret LINE (a null-terminated string) as a variable definition.

   ORIGIN may be o_file, o_override, o_env, o_env_override,
   or o_command specifying that the variable definition comes
   from a makefile, an override directive, the environment with
   or without the -e switch, or the command line.

   A variable definition has the form "name = value" or "name := value".
   Any whitespace around the "=" or ":=" is removed.  The first form
   defines a variable that is recursively re-evaluated.  The second form
   defines a variable whose value is variable-expanded at the time of
   definition and then is evaluated only once at the time of expansion.

   If a variable was defined, a pointer to its `struct variable' is returned.
   If not, NULL is returned.  */

struct variable *
try_variable_definition (filename, lineno, line, origin)
     char *filename;
     unsigned int lineno;
     char *line;
     enum variable_origin origin;
{
  register int c;
  register char *p = line;
  register char *beg;
  register char *end;
  enum { bogus, simple, recursive, append } flavor = bogus;
  char *name, *expanded_name, *value;
  struct variable *v;

  while (1)
    {
      c = *p++;
      if (c == '\0' || c == '#')
        return 0;
      if (c == '=')
        {
          end = p - 1;
          flavor = recursive;
          break;
        }
      else if (c == ':')
        if (*p == '=')
          {
            end = p++ - 1;
            flavor = simple;
            break;
          }
        else
          /* A colon other than := is a rule line, not a variable defn.  */
          return 0;
      else if (c == '+' && *p == '=')
        {
          end = p++ - 1;
          flavor = append;
          break;
        }
    }

  while (isblank (end[-1]))
    --end;
  beg = next_token (line);
  p = next_token (p);

  /* Expand the name, so "$(foo)bar = baz" works.  */
  name = (char *) alloca (end - beg + 1);
  bcopy (beg, name, end - beg);
  name[end - beg] = '\0';
  expanded_name = allocated_variable_expand (name);

  if (expanded_name[0] == '\0')
    {
      if (filename == 0)
        fatal ("empty variable name");
      else
        makefile_fatal (filename, lineno, "empty variable name");
    }

  /* Calculate the variable's new value in VALUE.  */

  switch (flavor)
    {
    case bogus:
      /* Should not be possible.  */
      abort ();
      break;
    case simple:
      /* A simple variable definition "var := value".  Expand the value.  */
      value = variable_expand (p);
      break;
    case recursive:
      /* A recursive variable definition "var = value".
         The value is used verbatim.  */
      value = p;
      break;
    case append:
      /* An appending variable definition "var += value".
         Extract the old value and append the new one.  */
      v = lookup_variable (expanded_name, strlen (expanded_name));
      if (v == 0)
        {
          /* There was no old value.
             This becomes a normal recursive definition.  */
          value = p;
          flavor = recursive;
        }
      else
        {
          /* Paste the old and new values together in VALUE.  */

          unsigned int oldlen, newlen;

          if (v->recursive)
            /* The previous definition of the variable was recursive.
               The new value comes from the unexpanded old and new values.  */
            flavor = recursive;
          else
            /* The previous definition of the variable was simple.
               The new value comes from the old value, which was expanded
               when it was set; and from the expanded new value.  */
            p = variable_expand (p);

          oldlen = strlen (v->value);
          newlen = strlen (p);
          value = (char *) alloca (oldlen + 1 + newlen + 1);
          bcopy (v->value, value, oldlen);
          value[oldlen] = ' ';
          bcopy (p, &value[oldlen + 1], newlen + 1);
        }
    }

  v = define_variable (expanded_name, strlen (expanded_name),
                       value, origin, flavor == recursive);

  free (expanded_name);

  return v;
}
\f
/* Print information for variable V, prefixing it with PREFIX.  */

static void
print_variable (v, prefix)
     register struct variable *v;
     char *prefix;
{
  char *origin;

  switch (v->origin)
    {
    case o_default:
      origin = "default";
      break;
    case o_env:
      origin = "environment";
      break;
    case o_file:
      origin = "makefile";
      break;
    case o_env_override:
      origin = "environment under -e";
      break;
    case o_command:
      origin = "command line";
      break;
    case o_override:
      origin = "`override' directive";
      break;
    case o_automatic:
      origin = "automatic";
      break;
    case o_invalid:
    default:
      abort ();
      break;
    }
  printf ("# %s\n", origin);

  fputs (prefix, stdout);

  /* Is this a `define'?  */
  if (v->recursive && index (v->value, '\n') != 0)
    printf ("define %s\n%s\nendef\n", v->name, v->value);
  else
    {
      register char *p;

      printf ("%s %s= ", v->name, v->recursive ? "" : ":");

      /* Check if the value is just whitespace.  */
      p = next_token (v->value);
      if (p != v->value && *p == '\0')
        /* All whitespace.  */
        printf ("$(subst ,,%s)", v->value);
      else if (v->recursive)
        fputs (v->value, stdout);
      else
        /* Double up dollar signs.  */
        for (p = v->value; *p != '\0'; ++p)
          {
            if (*p == '$')
              putchar ('$');
            putchar (*p);
          }
      putchar ('\n');
    }
}


/* Print all the variables in SET.  PREFIX is printed before
   the actual variable definitions (everything else is comments).  */

static void
print_variable_set (set, prefix)
     register struct variable_set *set;
     char *prefix;
{
  register unsigned int i, nvariables, per_bucket;
  register struct variable *v;

  per_bucket = nvariables = 0;
  for (i = 0; i < set->buckets; ++i)
    {
      register unsigned int this_bucket = 0;

      for (v = set->table[i]; v != 0; v = v->next)
        {
          ++this_bucket;
          print_variable (v, prefix);
        }

      nvariables += this_bucket;
      if (this_bucket > per_bucket)
        per_bucket = this_bucket;
    }

  if (nvariables == 0)
    puts ("# No variables.");
  else
    {
      printf ("# %u variables in %u hash buckets.\n",
              nvariables, set->buckets);
#ifndef NO_FLOAT
      printf ("# average of %.1f variables per bucket, \
max %u in one bucket.\n",
              (double) nvariables / (double) set->buckets,
              per_bucket);
#endif
    }
}


/* Print the data base of variables.  */

void
print_variable_data_base ()
{
  puts ("\n# Variables\n");

  print_variable_set (&global_variable_set, "");
}


/* Print all the local variables of FILE.  */

void
print_file_variables (file)
     struct file *file;
{
  if (file->variables != 0)
    print_variable_set (file->variables->set, "# ");
}