tlink.c

/* Scan linker error messages for missing template instantiations and provide
   them.

   Copyright (C) 1995, 1998, 1999 Free Software Foundation, Inc.
   Contributed by Jason Merrill (jason@cygnus.com).

This file is part of GNU CC.

GNU CC 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 CC 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 CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include "config.h"
#include "system.h"
#include "hash.h"
#include "demangle.h"
#include "collect2.h"

#define MAX_ITERATIONS 17

/* Obstack allocation and deallocation routines.  */
#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free

/* Defined in the automatically-generated underscore.c.  */
extern int prepends_underscore;

static int tlink_verbose;

/* Hash table boilerplate for working with hash.[ch].  We have hash tables
   for symbol names, file names, and demangled symbols.  */

typedef struct symbol_hash_entry
{
  struct hash_entry root;
  struct file_hash_entry *file;
  int chosen;
  int tweaking;
  int tweaked;
} symbol;

typedef struct file_hash_entry
{
  struct hash_entry root;
  const char *args;
  const char *dir;
  const char *main;
  int tweaking;
} file;

typedef struct demangled_hash_entry
{
  struct hash_entry root;
  const char *mangled;
} demangled;

static struct hash_table symbol_table;

static struct hash_entry * symbol_hash_newfunc PARAMS ((struct hash_entry *,
							struct hash_table *,
							hash_table_key));
static struct symbol_hash_entry * symbol_hash_lookup PARAMS ((const char *,
							      boolean));
static struct hash_entry * file_hash_newfunc PARAMS ((struct hash_entry *,
						      struct hash_table *,
						      hash_table_key));
static struct file_hash_entry * file_hash_lookup PARAMS ((const char *));
static struct hash_entry * demangled_hash_newfunc PARAMS ((struct hash_entry *,
							   struct hash_table *,
							   hash_table_key));
static struct demangled_hash_entry *
  demangled_hash_lookup PARAMS ((const char *, boolean));
static void symbol_push PARAMS ((symbol *));
static symbol * symbol_pop PARAMS ((void));
static void file_push PARAMS ((file *));
static file * file_pop PARAMS ((void));
static void tlink_init PARAMS ((void));
static int tlink_execute PARAMS ((const char *, char **, const char *));
static char * frob_extension PARAMS ((const char *, const char *));
static char * obstack_fgets PARAMS ((FILE *, struct obstack *));
static char * tfgets PARAMS ((FILE *));
static char * pfgets PARAMS ((FILE *));
static void freadsym PARAMS ((FILE *, file *, int));
static void read_repo_file PARAMS ((file *));
static void maybe_tweak PARAMS ((char *, file *));
static int recompile_files PARAMS ((void));
static int read_repo_files PARAMS ((char **));
static void demangle_new_symbols PARAMS ((void));
static int scan_linker_output PARAMS ((const char *));

/* Create a new entry for the symbol hash table.
   Passed to hash_table_init.  */

static struct hash_entry *
symbol_hash_newfunc (entry, table, string)
     struct hash_entry *entry;
     struct hash_table *table;
     hash_table_key string ATTRIBUTE_UNUSED;
{
  struct symbol_hash_entry *ret = (struct symbol_hash_entry *) entry;
  if (ret == NULL)
    {
      ret = ((struct symbol_hash_entry *)
	     hash_allocate (table, sizeof (struct symbol_hash_entry)));
      if (ret == NULL)
	return NULL;
    }
  ret->file = NULL;
  ret->chosen = 0;
  ret->tweaking = 0;
  ret->tweaked = 0;
  return (struct hash_entry *) ret;
}

/* Look up an entry in the symbol hash table.  */

static struct symbol_hash_entry *
symbol_hash_lookup (string, create)
     const char *string;
     boolean create;
{
  return ((struct symbol_hash_entry *)
	  hash_lookup (&symbol_table, (const hash_table_key) string, 
		       create, string_copy));
}

static struct hash_table file_table;

/* Create a new entry for the file hash table.
   Passed to hash_table_init.  */

static struct hash_entry *
file_hash_newfunc (entry, table, string)
     struct hash_entry *entry;
     struct hash_table *table;
     hash_table_key string ATTRIBUTE_UNUSED;
{
   struct file_hash_entry *ret = (struct file_hash_entry *) entry;
  if (ret == NULL)
    {
      ret = ((struct file_hash_entry *)
	     hash_allocate (table, sizeof (struct file_hash_entry)));
      if (ret == NULL)
	return NULL;
    }
  ret->args = NULL;
  ret->dir = NULL;
  ret->main = NULL;
  ret->tweaking = 0;
  return (struct hash_entry *) ret;
}

/* Look up an entry in the file hash table.  */

static struct file_hash_entry *
file_hash_lookup (string)
     const char *string;
{
  return ((struct file_hash_entry *)
	  hash_lookup (&file_table, (const hash_table_key) string, true, 
		       string_copy));
}

static struct hash_table demangled_table;

/* Create a new entry for the demangled name hash table.
   Passed to hash_table_init.  */

static struct hash_entry *
demangled_hash_newfunc (entry, table, string)
     struct hash_entry *entry;
     struct hash_table *table;
     hash_table_key string ATTRIBUTE_UNUSED;
{
  struct demangled_hash_entry *ret = (struct demangled_hash_entry *) entry;
  if (ret == NULL)
    {
      ret = ((struct demangled_hash_entry *)
	     hash_allocate (table, sizeof (struct demangled_hash_entry)));
      if (ret == NULL)
	return NULL;
    }
  ret->mangled = NULL;
  return (struct hash_entry *) ret;
}

/* Look up an entry in the demangled name hash table.  */

static struct demangled_hash_entry *
demangled_hash_lookup (string, create)
     const char *string;
     boolean create;
{
  return ((struct demangled_hash_entry *)
	  hash_lookup (&demangled_table, (const hash_table_key) string, 
		       create, string_copy));
}

/* Stack code.  */

struct symbol_stack_entry
{
  symbol *value;
  struct symbol_stack_entry *next;
};
struct obstack symbol_stack_obstack;
struct symbol_stack_entry *symbol_stack;

struct file_stack_entry
{
  file *value;
  struct file_stack_entry *next;
};
struct obstack file_stack_obstack;
struct file_stack_entry *file_stack;

static void
symbol_push (p)
     symbol *p;
{
  struct symbol_stack_entry *ep = (struct symbol_stack_entry *) obstack_alloc
    (&symbol_stack_obstack, sizeof (struct symbol_stack_entry));
  ep->value = p;
  ep->next = symbol_stack;
  symbol_stack = ep;
}

static symbol *
symbol_pop ()
{
  struct symbol_stack_entry *ep = symbol_stack;
  symbol *p;
  if (ep == NULL)
    return NULL;
  p = ep->value;
  symbol_stack = ep->next;
  obstack_free (&symbol_stack_obstack, ep);
  return p;
}

static void
file_push (p)
     file *p;
{
  struct file_stack_entry *ep;

  if (p->tweaking)
    return;

  ep = (struct file_stack_entry *) obstack_alloc
    (&file_stack_obstack, sizeof (struct file_stack_entry));
  ep->value = p;
  ep->next = file_stack;
  file_stack = ep;
  p->tweaking = 1;
}

static file *
file_pop ()
{
  struct file_stack_entry *ep = file_stack;
  file *p;
  if (ep == NULL)
    return NULL;
  p = ep->value;
  file_stack = ep->next;
  obstack_free (&file_stack_obstack, ep);
  p->tweaking = 0;
  return p;
}

/* Other machinery.  */

/* Initialize the tlink machinery.  Called from do_tlink.  */

static void
tlink_init ()
{
  const char *p;

  hash_table_init (&symbol_table, symbol_hash_newfunc, string_hash,
		   string_compare);
  hash_table_init (&file_table, file_hash_newfunc, string_hash, 
		   string_compare);
  hash_table_init (&demangled_table, demangled_hash_newfunc,
		   string_hash, string_compare);
  obstack_begin (&symbol_stack_obstack, 0);
  obstack_begin (&file_stack_obstack, 0);

  p = getenv ("TLINK_VERBOSE");
  if (p)
    tlink_verbose = atoi (p);
  else
    {
      tlink_verbose = 1;
      if (vflag)
	tlink_verbose = 2;
      if (debug)
	tlink_verbose = 3;
    }
}

static int
tlink_execute (prog, argv, redir)
     const char *prog;
     char **argv;
     const char *redir;
{
  collect_execute (prog, argv, redir);
  return collect_wait (prog);
} 

static char *
frob_extension (s, ext)
     const char *s;
     const char *ext;
{
  const char *p = rindex (s, '/');
  if (! p)
    p = s;
  p = rindex (p, '.');
  if (! p)
    p = s + strlen (s);

  obstack_grow (&temporary_obstack, s, p - s);
  return obstack_copy0 (&temporary_obstack, ext, strlen (ext));
}

static char *
obstack_fgets (stream, ob)
     FILE *stream;
     struct obstack *ob;
{
  int c;
  while ((c = getc (stream)) != EOF && c != '\n')
    obstack_1grow (ob, c);
  if (obstack_object_size (ob) == 0)
    return NULL;
  obstack_1grow (ob, '\0');
  return obstack_finish (ob);
}

static char *
tfgets (stream)
     FILE *stream;
{
  return obstack_fgets (stream, &temporary_obstack);
}

static char *
pfgets (stream)
     FILE *stream;
{
  return obstack_fgets (stream, &permanent_obstack);
}

/* Real tlink code.  */

/* Subroutine of read_repo_file.  We are reading the repo file for file F,
   which is coming in on STREAM, and the symbol that comes next in STREAM
   is offerred, chosen or provided if CHOSEN is 0, 1 or 2, respectively.

   XXX "provided" is unimplemented, both here and in the compiler.  */

static void
freadsym (stream, f, chosen)
     FILE *stream;
     file *f;
     int chosen;
{
  symbol *sym;

  {
    const char *name = tfgets (stream);
    sym = symbol_hash_lookup (name, true);
  }

  if (sym->file == NULL)
    {
      /* We didn't have this symbol already, so we choose this file.  */

      symbol_push (sym);
      sym->file = f;
      sym->chosen = chosen;
    }
  else if (chosen)
    {
      /* We want this file; cast aside any pretender.  */

      if (sym->chosen && sym->file != f)
	{
	  if (sym->chosen == 1)
	    file_push (sym->file);
	  else
	    {
	      file_push (f);
	      f = sym->file;
	      chosen = sym->chosen;
	    }
	}
      sym->file = f;
      sym->chosen = chosen;
    }
}

/* Read in the repo file denoted by F, and record all its information.  */

static void
read_repo_file (f)
     file *f;
{
  char c;
  FILE *stream = fopen ((char*) f->root.key, "r");

  if (tlink_verbose >= 2)
    fprintf (stderr, "collect: reading %s\n", 
	     (char*) f->root.key);

  while (fscanf (stream, "%c ", &c) == 1)
    {
      switch (c)
	{
	case 'A':
	  f->args = pfgets (stream);
	  break;
	case 'D':
	  f->dir = pfgets (stream);
	  break;
	case 'M':
	  f->main = pfgets (stream);
	  break;
	case 'P':
	  freadsym (stream, f, 2);
	  break;
	case 'C':
	  freadsym (stream, f, 1);
	  break;
	case 'O':
	  freadsym (stream, f, 0);
	  break;
	}
      obstack_free (&temporary_obstack, temporary_firstobj);
    }
  fclose (stream);
  if (f->args == NULL)
    f->args = getenv ("COLLECT_GCC_OPTIONS");
  if (f->dir == NULL)
    f->dir = ".";
}

/* We might want to modify LINE, which is a symbol line from file F.  We do
   this if either we saw an error message referring to the symbol in
   question, or we have already allocated the symbol to another file and
   this one wants to emit it as well.  */

static void
maybe_tweak (line, f)
     char *line;
     file *f;
{
  symbol *sym = symbol_hash_lookup (line + 2, false);

  if ((sym->file == f && sym->tweaking)
      || (sym->file != f && line[0] == 'C'))
    {
      sym->tweaking = 0;
      sym->tweaked = 1;

      if (line[0] == 'O')
	line[0] = 'C';
      else
	line[0] = 'O';
    }
}

/* Update the repo files for each of the object files we have adjusted and
   recompile.

   XXX Should this use collect_execute instead of system?  */

static int
recompile_files ()
{
  file *f;

  while ((f = file_pop ()) != NULL)
    {
      char *line, *command;
      FILE *stream = fopen ((char*) f->root.key, "r");
      const char *outname = frob_extension ((char*) f->root.key, ".rnw");
      FILE *output = fopen (outname, "w");

      while ((line = tfgets (stream)) != NULL)
	{
	  switch (line[0])
	    {
	    case 'C':
	    case 'O':
	      maybe_tweak (line, f);
	    }
	  fprintf (output, "%s\n", line);
	}
      fclose (stream);
      fclose (output);
      rename (outname, (char*) f->root.key);

      obstack_grow (&temporary_obstack, "cd ", 3);
      obstack_grow (&temporary_obstack, f->dir, strlen (f->dir));
      obstack_grow (&temporary_obstack, "; ", 2);
      obstack_grow (&temporary_obstack, c_file_name, strlen (c_file_name));
      obstack_1grow (&temporary_obstack, ' ');
      obstack_grow (&temporary_obstack, f->args, strlen (f->args));
      obstack_1grow (&temporary_obstack, ' ');
      command = obstack_copy0 (&temporary_obstack, f->main, strlen (f->main));

      if (tlink_verbose)
	fprintf (stderr, "collect: recompiling %s\n", f->main);
      if (tlink_verbose >= 3)
	fprintf (stderr, "%s\n", command);

      if (system (command) != 0)
	return 0;

      read_repo_file (f);

      obstack_free (&temporary_obstack, temporary_firstobj);
    }
  return 1;
}

/* The first phase of processing: determine which object files have
   .rpo files associated with them, and read in the information.  */

static int
read_repo_files (object_lst)
     char **object_lst;
{
  char **object = object_lst;

  for (; *object; object++)
    {
      const char *p = frob_extension (*object, ".rpo");
      file *f;

      if (! file_exists (p))
	continue;

      f = file_hash_lookup (p);

      read_repo_file (f);
    }

  if (file_stack != NULL && ! recompile_files ())
    return 0;

  return (symbol_stack != NULL);
}

/* Add the demangled forms of any new symbols to the hash table.  */

static void
demangle_new_symbols ()
{
  symbol *sym;

  while ((sym = symbol_pop ()) != NULL)
    {
      demangled *dem;
      const char *p = cplus_demangle ((char*) sym->root.key, 
				DMGL_PARAMS | DMGL_ANSI);

      if (! p)
	continue;

      dem = demangled_hash_lookup (p, true);
      dem->mangled = (char*) sym->root.key;
    }
}

/* Step through the output of the linker, in the file named FNAME, and
   adjust the settings for each symbol encountered.  */

static int
scan_linker_output (fname)
     const char *fname;
{
  FILE *stream = fopen (fname, "r");
  char *line;

  while ((line = tfgets (stream)) != NULL)
    {
      char *p = line, *q;
      symbol *sym;
      int end;
      
      while (*p && ISSPACE ((unsigned char)*p))
	++p;

      if (! *p)
	continue;

      for (q = p; *q && ! ISSPACE ((unsigned char)*q); ++q)
	;

      /* Try the first word on the line.  */
      if (*p == '.')
	++p;
      if (*p == '_' && prepends_underscore)
	++p;

      end = ! *q;
      *q = 0;
      sym = symbol_hash_lookup (p, false);

      if (! sym && ! end)
	/* Try a mangled name in quotes.  */
	{
	  const char *oldq = q+1;
	  demangled *dem = 0;
	  q = 0;

	  /* First try `GNU style'.  */
	  p = index (oldq, '`');
	  if (p)
	    p++, q = index (p, '\'');
	  /* Then try "double quotes".  */
	  else if (p = index (oldq, '"'), p)
	    p++, q = index (p, '"');

	  /* We need to check for certain error keywords here, or we would
	     mistakenly use GNU ld's "In function `foo':" message.  */
	  if (q && (strstr (oldq, "ndefined")
		    || strstr (oldq, "nresolved")
		    || strstr (oldq, "ultiple")))
	    {
	      *q = 0;
	      dem = demangled_hash_lookup (p, false);
	      if (dem)
		sym = symbol_hash_lookup (dem->mangled, false);
	      else
	        {
	          if (*p == '_' && prepends_underscore)
		    ++p;
		  sym = symbol_hash_lookup (p, false);
		}
	    }
	}

      if (sym && sym->tweaked)
	{
	  fclose (stream);
	  return 0;
	}
      if (sym && !sym->tweaking)
	{
	  if (tlink_verbose >= 2)
	    fprintf (stderr, "collect: tweaking %s in %s\n",
		     (char*) sym->root.key, (char*) sym->file->root.key);
	  sym->tweaking = 1;
	  file_push (sym->file);
	}
	
      obstack_free (&temporary_obstack, temporary_firstobj);
    }

  fclose (stream);
  return (file_stack != NULL);
}

/* Entry point for tlink.  Called from main in collect2.c.

   Iteratively try to provide definitions for all the unresolved symbols
   mentioned in the linker error messages.

   LD_ARGV is an array of arguments for the linker.
   OBJECT_LST is an array of object files that we may be able to recompile
     to provide missing definitions.  Currently ignored.  */

void
do_tlink (ld_argv, object_lst)
     char **ld_argv, **object_lst ATTRIBUTE_UNUSED;
{
  int exit = tlink_execute ("ld", ld_argv, ldout);

  tlink_init ();

  if (exit)
    {
      int i = 0;

      /* Until collect does a better job of figuring out which are object
	 files, assume that everything on the command line could be.  */
      if (read_repo_files (ld_argv))
	while (exit && i++ < MAX_ITERATIONS)
	  {
	    if (tlink_verbose >= 3)
	      dump_file (ldout);
	    demangle_new_symbols ();
	    if (! scan_linker_output (ldout))
	      break;
	    if (! recompile_files ())
	      break;
	    if (tlink_verbose)
	      fprintf (stderr, "collect: relinking\n");
	    exit = tlink_execute ("ld", ld_argv, ldout);
	  }
    }

  dump_file (ldout);
  unlink (ldout);
  if (exit)
    {
      error ("ld returned %d exit status", exit);
      collect_exit (exit);
    }
}