src/src/ldscript.y

%{
/* Parser for linker scripts.
   Copyright (C) 2001-2011 Red Hat, Inc.
   This file is part of Red Hat elfutils.
   Written by Ulrich Drepper <drepper@redhat.com>, 2001.

   Red Hat elfutils 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; version 2 of the License.

   Red Hat elfutils 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 Red Hat elfutils; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.

   Red Hat elfutils is an included package of the Open Invention Network.
   An included package of the Open Invention Network is a package for which
   Open Invention Network licensees cross-license their patents.  No patent
   license is granted, either expressly or impliedly, by designation as an
   included package.  Should you wish to participate in the Open Invention
   Network licensing program, please visit www.openinventionnetwork.com
   <http://www.openinventionnetwork.com>.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <assert.h>
#include <error.h>
#include <libintl.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <system.h>
#include <ld.h>

/* The error handler.  */
static void yyerror (const char *s);

/* Some helper functions we need to construct the data structures
   describing information from the file.  */
static struct expression *new_expr (int tag);
static struct input_section_name *new_input_section_name (const char *name,
							  bool sort_flag);
static struct input_rule *new_input_rule (int tag);
static struct output_rule *new_output_rule (int tag);
static struct assignment *new_assignment (const char *variable,
					  struct expression *expression,
					  bool provide_flag);
static void new_segment (int mode, struct output_rule *output_rule);
static struct filename_list *new_filename_listelem (const char *string);
static void add_inputfiles (struct filename_list *fnames);
static struct id_list *new_id_listelem (const char *str);
 static struct filename_list *mark_as_needed (struct filename_list *listp);
static struct version *new_version (struct id_list *local,
				    struct id_list *global);
static struct version *merge_versions (struct version *one,
				       struct version *two);
static void add_versions (struct version *versions);

extern int yylex (void);
%}

%union {
  uintmax_t num;
  enum expression_tag op;
  char *str;
  struct expression *expr;
  struct input_section_name *sectionname;
  struct filemask_section_name *filemask_section_name;
  struct input_rule *input_rule;
  struct output_rule *output_rule;
  struct assignment *assignment;
  struct filename_list *filename_list;
  struct version *version;
  struct id_list *id_list;
}

%token kADD_OP
%token kALIGN
%token kAS_NEEDED
%token kENTRY
%token kEXCLUDE_FILE
%token <str> kFILENAME
%token kGLOBAL
%token kGROUP
%token <str> kID
%token kINPUT
%token kINTERP
%token kKEEP
%token kLOCAL
%token <num> kMODE
%token kMUL_OP
%token <num> kNUM
%token kOUTPUT_FORMAT
%token kPAGESIZE
%token kPROVIDE
%token kSEARCH_DIR
%token kSEGMENT
%token kSIZEOF_HEADERS
%token kSORT
%token kVERSION
%token kVERSION_SCRIPT

%left '|'
%left '&'
%left ADD_OP
%left MUL_OP '*'

%type <op> kADD_OP
%type <op> kMUL_OP
%type <str> filename_id
%type <str> filename_id_star
%type <str> exclude_opt
%type <expr> expr
%type <sectionname> sort_opt_name
%type <filemask_section_name> sectionname
%type <input_rule> inputsection
%type <input_rule> inputsections
%type <output_rule> outputsection
%type <output_rule> outputsections
%type <assignment> assignment
%type <filename_list> filename_id_list
%type <filename_list> filename_id_listelem
%type <version> versionlist
%type <version> version
%type <version> version_stmt_list
%type <version> version_stmt
%type <id_list> filename_id_star_list

%expect 16

%%

script_or_version:
		  file
		| kVERSION_SCRIPT versionlist
		    { add_versions ($2); }
		;

file:		  file content
		| content
		;

content:	  kENTRY '(' kID ')' ';'
		    {
		      if (likely (ld_state.entry == NULL))
			ld_state.entry = $3;
		    }
		| kSEARCH_DIR '(' filename_id ')' ';'
		    {
		      ld_new_searchdir ($3);
		    }
		| kPAGESIZE '(' kNUM ')' ';'
		    {
		      if (likely (ld_state.pagesize == 0))
			ld_state.pagesize = $3;
		    }
		| kINTERP '(' filename_id ')' ';'
		    {
		      if (likely (ld_state.interp == NULL)
			  && ld_state.file_type != dso_file_type)
			ld_state.interp = $3;
		    }
		| kSEGMENT kMODE '{' outputsections '}'
		    {
		      new_segment ($2, $4);
		    }
		| kSEGMENT error '{' outputsections '}'
		    {
		      fputs_unlocked (gettext ("mode for segment invalid\n"),
				      stderr);
		      new_segment (0, $4);
		    }
		| kGROUP '(' filename_id_list ')'
		    {
		      /* First little optimization.  If there is only one
			 file in the group don't do anything.  */
		      if ($3 != $3->next)
			{
			  $3->next->group_start = 1;
			  $3->group_end = 1;
			}
		      add_inputfiles ($3);
		    }
		| kINPUT '(' filename_id_list ')'
		    { add_inputfiles ($3); }
		| kAS_NEEDED '(' filename_id_list ')'
		    { add_inputfiles (mark_as_needed ($3)); }
		| kVERSION '{' versionlist '}'
		    { add_versions ($3); }
		| kOUTPUT_FORMAT '(' filename_id ')'
		    { /* XXX TODO */ }
		;

outputsections:	  outputsections outputsection
		    {
		      $2->next = $1->next;
		      $$ = $1->next = $2;
		    }
		| outputsection
		    { $$ = $1; }
		;

outputsection:	  assignment ';'
		    {
		      $$ = new_output_rule (output_assignment);
		      $$->val.assignment = $1;
		    }
		| kID '{' inputsections '}'
		    {
		      $$ = new_output_rule (output_section);
		      $$->val.section.name = $1;
		      $$->val.section.input = $3->next;
		      if (ld_state.strip == strip_debug
			  && ebl_debugscn_p (ld_state.ebl, $1))
			$$->val.section.ignored = true;
		      else
			$$->val.section.ignored = false;
		      $3->next = NULL;
		    }
		| kID ';'
		    {
		      /* This is a short cut for "ID { *(ID) }".  */
		      $$ = new_output_rule (output_section);
		      $$->val.section.name = $1;
		      $$->val.section.input = new_input_rule (input_section);
		      $$->val.section.input->next = NULL;
		      $$->val.section.input->val.section =
			(struct filemask_section_name *)
			  obstack_alloc (&ld_state.smem,
					 sizeof (struct filemask_section_name));
		      $$->val.section.input->val.section->filemask = NULL;
		      $$->val.section.input->val.section->excludemask = NULL;
		      $$->val.section.input->val.section->section_name =
			new_input_section_name ($1, false);
		      $$->val.section.input->val.section->keep_flag = false;
		      if (ld_state.strip == strip_debug
			  && ebl_debugscn_p (ld_state.ebl, $1))
			$$->val.section.ignored = true;
		      else
			$$->val.section.ignored = false;
		    }
		;

assignment:	  kID '=' expr
		    { $$ = new_assignment ($1, $3, false); }
		| kPROVIDE '(' kID '=' expr ')'
		    { $$ = new_assignment ($3, $5, true); }
		;

inputsections:	  inputsections inputsection
		    {
		      $2->next = $1->next;
		      $$ = $1->next = $2;
		    }
		| inputsection
		    { $$ = $1; }
		;

inputsection:	  sectionname
		    {
		      $$ = new_input_rule (input_section);
		      $$->val.section = $1;
		    }
		| kKEEP '(' sectionname ')'
		    {
		      $3->keep_flag = true;

		      $$ = new_input_rule (input_section);
		      $$->val.section = $3;
		    }
		| assignment ';'
		    {
		      $$ = new_input_rule (input_assignment);
		      $$->val.assignment = $1;
		    }
		;

sectionname:	  filename_id_star '(' exclude_opt sort_opt_name ')'
		    {
		      $$ = (struct filemask_section_name *)
			obstack_alloc (&ld_state.smem, sizeof (*$$));
		      $$->filemask = $1;
		      $$->excludemask = $3;
		      $$->section_name = $4;
		      $$->keep_flag = false;
		    }
		;

sort_opt_name:	  kID
		    { $$ = new_input_section_name ($1, false); }
		| kSORT '(' kID ')'
		    { $$ = new_input_section_name ($3, true); }
		;

exclude_opt:	  kEXCLUDE_FILE '(' filename_id ')'
		    { $$ = $3; }
		|
		    { $$ = NULL; }
		;

expr:		  kALIGN '(' expr ')'
		    {
		      $$ = new_expr (exp_align);
		      $$->val.child = $3;
		    }
		| '(' expr ')'
		    { $$ = $2; }
		| expr '*' expr
		    {
		      $$ = new_expr (exp_mult);
		      $$->val.binary.left = $1;
		      $$->val.binary.right = $3;
		    }
		| expr kMUL_OP expr
		    {
		      $$ = new_expr ($2);
		      $$->val.binary.left = $1;
		      $$->val.binary.right = $3;
		    }
		| expr kADD_OP expr
		    {
		      $$ = new_expr ($2);
		      $$->val.binary.left = $1;
		      $$->val.binary.right = $3;
		    }
		| expr '&' expr
		    {
		      $$ = new_expr (exp_and);
		      $$->val.binary.left = $1;
		      $$->val.binary.right = $3;
		    }
		| expr '|' expr
		    {
		      $$ = new_expr (exp_or);
		      $$->val.binary.left = $1;
		      $$->val.binary.right = $3;
		    }
		| kNUM
		    {
		      $$ = new_expr (exp_num);
		      $$->val.num = $1;
		    }
		| kID
		    {
		      $$ = new_expr (exp_id);
		      $$->val.str = $1;
		    }
		| kSIZEOF_HEADERS
		    { $$ = new_expr (exp_sizeof_headers); }
		| kPAGESIZE
		    { $$ = new_expr (exp_pagesize); }
		;

filename_id_list: filename_id_list comma_opt filename_id_listelem
		    {
		      $3->next = $1->next;
		      $$ = $1->next = $3;
		    }
		| filename_id_listelem
		    { $$ = $1; }
		;

comma_opt:	  ','
		|
		;

filename_id_listelem: kGROUP '(' filename_id_list ')'
		    {
		      /* First little optimization.  If there is only one
			 file in the group don't do anything.  */
		      if ($3 != $3->next)
			{
			  $3->next->group_start = 1;
			  $3->group_end = 1;
			}
		      $$ = $3;
		    }
		| kAS_NEEDED '(' filename_id_list ')'
		    { $$ = mark_as_needed ($3); }
		| filename_id
		    { $$ = new_filename_listelem ($1); }
		;


versionlist:	  versionlist version
		    {
		      $2->next = $1->next;
		      $$ = $1->next = $2;
		    }
		| version
		    { $$ = $1; }
		;

version:	  '{' version_stmt_list '}' ';'
		    {
		      $2->versionname = "";
		      $2->parentname = NULL;
		      $$ = $2;
		    }
		| filename_id '{' version_stmt_list '}' ';'
		    {
		      $3->versionname = $1;
		      $3->parentname = NULL;
		      $$ = $3;
		    }
		| filename_id '{' version_stmt_list '}' filename_id ';'
		    {
		      $3->versionname = $1;
		      $3->parentname = $5;
		      $$ = $3;
		    }
		;

version_stmt_list:
		  version_stmt_list version_stmt
		    { $$ = merge_versions ($1, $2); }
		| version_stmt
		    { $$ = $1; }
		;

version_stmt:	  kGLOBAL filename_id_star_list
		    { $$ = new_version (NULL, $2); }
		| kLOCAL filename_id_star_list
		    { $$ = new_version ($2, NULL); }
		;

filename_id_star_list:
		  filename_id_star_list filename_id_star ';'
		    {
		      struct id_list *newp = new_id_listelem ($2);
		      newp->next = $1->next;
		      $$ = $1->next = newp;
		    }
		| filename_id_star ';'
		    { $$ = new_id_listelem ($1); }
		;

filename_id:	  kFILENAME
		    { $$ = $1; }
		| kID
		    { $$ = $1; }
		;

filename_id_star: filename_id
		    { $$ = $1; }
		| '*'
		    { $$ = NULL; }
		;

%%

static void
yyerror (const char *s)
{
  error (0, 0, (ld_scan_version_script
		? gettext ("while reading version script '%s': %s at line %d")
		: gettext ("while reading linker script '%s': %s at line %d")),
	 ldin_fname, gettext (s), ldlineno);
}


static struct expression *
new_expr (int tag)
{
  struct expression *newp = (struct expression *)
    obstack_alloc (&ld_state.smem, sizeof (*newp));

  newp->tag = tag;
  return newp;
}


static struct input_section_name *
new_input_section_name (const char *name, bool sort_flag)
{
  struct input_section_name *newp = (struct input_section_name *)
    obstack_alloc (&ld_state.smem, sizeof (*newp));

  newp->name = name;
  newp->sort_flag = sort_flag;
  return newp;
}


static struct input_rule *
new_input_rule (int tag)
{
  struct input_rule *newp = (struct input_rule *)
    obstack_alloc (&ld_state.smem, sizeof (*newp));

  newp->tag = tag;
  newp->next = newp;
  return newp;
}


static struct output_rule *
new_output_rule (int tag)
{
  struct output_rule *newp = (struct output_rule *)
    memset (obstack_alloc (&ld_state.smem, sizeof (*newp)),
	    '\0', sizeof (*newp));

  newp->tag = tag;
  newp->next = newp;
  return newp;
}


static struct assignment *
new_assignment (const char *variable, struct expression *expression,
		bool provide_flag)
{
  struct assignment *newp = (struct assignment *)
    obstack_alloc (&ld_state.smem, sizeof (*newp));

  newp->variable = variable;
  newp->expression = expression;
  newp->sym = NULL;
  newp->provide_flag = provide_flag;

  /* Insert the symbol into a hash table.  We will later have to matc*/
  return newp;
}


static void
new_segment (int mode, struct output_rule *output_rule)
{
  struct output_segment *newp;

  newp
    = (struct output_segment *) obstack_alloc (&ld_state.smem, sizeof (*newp));
  newp->mode = mode;
  newp->next = newp;

  newp->output_rules = output_rule->next;
  output_rule->next = NULL;

  /* Enqueue the output segment description.  */
  if (ld_state.output_segments == NULL)
    ld_state.output_segments = newp;
  else
    {
      newp->next = ld_state.output_segments->next;
      ld_state.output_segments = ld_state.output_segments->next = newp;
    }

  /* If the output file should be stripped of all symbol set the flag
     in the structures of all output sections.  */
  if (mode == 0 && ld_state.strip == strip_all)
    {
      struct output_rule *runp;

      for (runp = newp->output_rules; runp != NULL; runp = runp->next)
	if (runp->tag == output_section)
	  runp->val.section.ignored = true;
    }
}


static struct filename_list *
new_filename_listelem (const char *string)
{
  struct filename_list *newp;

  /* We use calloc and not the obstack since this object can be freed soon.  */
  newp = (struct filename_list *) xcalloc (1, sizeof (*newp));
  newp->name = string;
  newp->next = newp;
  return newp;
}


static struct filename_list *
mark_as_needed (struct filename_list *listp)
{
  struct filename_list *runp = listp;
  do
    {
      runp->as_needed = true;
      runp = runp->next;
    }
  while (runp != listp);

  return listp;
}


static void
add_inputfiles (struct filename_list *fnames)
{
  assert (fnames != NULL);

  if (ld_state.srcfiles == NULL)
    ld_state.srcfiles = fnames;
  else
    {
      struct filename_list *first = ld_state.srcfiles->next;

      ld_state.srcfiles->next = fnames->next;
      fnames->next = first;
      ld_state.srcfiles->next = fnames;
    }
}


static _Bool
special_char_p (const char *str)
{
  while (*str != '\0')
    {
      if (__builtin_expect (*str == '*', 0)
	  || __builtin_expect (*str == '?', 0)
	  || __builtin_expect (*str == '[', 0))
	return true;

      ++str;
    }

  return false;
}


static struct id_list *
new_id_listelem (const char *str)
{
  struct id_list *newp;

  newp = (struct id_list *) obstack_alloc (&ld_state.smem, sizeof (*newp));
  if (str == NULL)
    newp->u.id_type = id_all;
  else if (__builtin_expect (special_char_p (str), false))
    newp->u.id_type = id_wild;
  else
    newp->u.id_type = id_str;
  newp->id = str;
  newp->next = newp;

  return newp;
}


static struct version *
new_version (struct id_list *local, struct id_list *global)
{
  struct version *newp;

  newp = (struct version *) obstack_alloc (&ld_state.smem, sizeof (*newp));
  newp->next = newp;
  newp->local_names = local;
  newp->global_names = global;
  newp->versionname = NULL;
  newp->parentname = NULL;

  return newp;
}


static struct version *
merge_versions (struct version *one, struct version *two)
{
  assert (two->local_names == NULL || two->global_names == NULL);

  if (two->local_names != NULL)
    {
      if (one->local_names == NULL)
	one->local_names = two->local_names;
      else
	{
	  two->local_names->next = one->local_names->next;
	  one->local_names = one->local_names->next = two->local_names;
	}
    }
  else
    {
      if (one->global_names == NULL)
	one->global_names = two->global_names;
      else
	{
	  two->global_names->next = one->global_names->next;
	  one->global_names = one->global_names->next = two->global_names;
	}
    }

  return one;
}


static void
add_id_list (const char *versionname, struct id_list *runp, _Bool local)
{
  struct id_list *lastp = runp;

  if (runp == NULL)
    /* Nothing to do.  */
    return;

  /* Convert into a simple single-linked list.  */
  runp = runp->next;
  assert (runp != NULL);
  lastp->next = NULL;

  do
    if (runp->u.id_type == id_str)
      {
	struct id_list *curp;
	struct id_list *defp;
	unsigned long int hval = elf_hash (runp->id);

	curp = runp;
	runp = runp->next;

	defp = ld_version_str_tab_find (&ld_state.version_str_tab, hval, curp);
	if (defp != NULL)
	  {
	    /* There is already a version definition for this symbol.  */
	    while (strcmp (defp->u.s.versionname, versionname) != 0)
	      {
		if (defp->next == NULL)
		  {
		    /* No version like this so far.  */
		    defp->next = curp;
		    curp->u.s.local = local;
		    curp->u.s.versionname = versionname;
		    curp->next = NULL;
		    defp = NULL;
		    break;
		  }

		defp = defp->next;
	      }

	    if (defp != NULL && defp->u.s.local != local)
	      error (EXIT_FAILURE, 0, versionname[0] == '\0'
		     ? gettext ("\
symbol '%s' is declared both local and global for unnamed version")
		     : gettext ("\
symbol '%s' is declared both local and global for version '%s'"),
		     runp->id, versionname);
	  }
	else
	  {
	    /* This is the first version definition for this symbol.  */
	    ld_version_str_tab_insert (&ld_state.version_str_tab, hval, curp);

	    curp->u.s.local = local;
	    curp->u.s.versionname = versionname;
	    curp->next = NULL;
	  }
      }
    else if (runp->u.id_type == id_all)
      {
	if (local)
	  {
	    if (ld_state.default_bind_global)
	      error (EXIT_FAILURE, 0,
		     gettext ("default visibility set as local and global"));
	    ld_state.default_bind_local = true;
	  }
	else
	  {
	    if (ld_state.default_bind_local)
	      error (EXIT_FAILURE, 0,
		     gettext ("default visibility set as local and global"));
	    ld_state.default_bind_global = true;
	  }

	runp = runp->next;
      }
    else
      {
	assert (runp->u.id_type == id_wild);
	/* XXX TBI */
	abort ();
      }
  while (runp != NULL);
}


static void
add_versions (struct version *versions)
{
  struct version *lastp = versions;

  if (versions == NULL)
    return;

  /* Convert into a simple single-linked list.  */
  versions = versions->next;
  assert (versions != NULL);
  lastp->next = NULL;

  do
    {
      add_id_list (versions->versionname, versions->local_names, true);
      add_id_list (versions->versionname, versions->global_names, false);

      versions = versions->next;
    }
  while (versions != NULL);
}