/**
* mds — A micro-display server
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This program 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.
*
* This program 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 "eliminate-dead-code.h"
#include <stdlib.h>
#include <errno.h>
/**
* Tree type constant shortener
*/
#define C(TYPE) MDS_KBDC_TREE_TYPE_##TYPE
/**
* Add an error to the error list
*
* @param NODE:const mds_kbdc_tree_t* The node the triggered the error
* @param SEVERITY:identifier * in `MDS_KBDC_PARSE_ERROR_*` to indicate severity
* @param ...:const char*, ... Error description format string and arguments
* @scope error:mds_kbdc_parse_error_t* Variable where the new error will be stored
*/
#define NEW_ERROR(NODE, SEVERITY, ...) \
NEW_ERROR_(result, SEVERITY, 1, (NODE)->loc_line, \
(NODE)->loc_start, (NODE)->loc_end, 1, __VA_ARGS__)
/**
* Add “included from here”-notes
*
* @param PTR:size_t The number of “included from here”-notes
*/
#define DUMP_INCLUDE_STACK(PTR) \
fail_if (dump_include_stack(PTR))
/**
* Add an error with “included from here”-notes to the error list
*
* @param NODE:const mds_kbdc_tree_t* The node the triggered the error
* @param PTR:size_t The number of “included from here”-notes
* @param SEVERITY:identifier * in `MDS_KBDC_PARSE_ERROR_*` to indicate severity
* @param ...:const char*, ... Error description format string and arguments
* @scope error:mds_kbdc_parse_error_t* Variable where the new error will be stored
*/
#define NEW_ERROR_WITH_INCLUDES(NODE, PTR, SEVERITY, ...) \
do \
{ \
NEW_ERROR(NODE, SEVERITY, __VA_ARGS__); \
DUMP_INCLUDE_STACK(PTR); \
} \
while (0)
/**
* Variable whether the latest created error is stored
*/
static mds_kbdc_parse_error_t* error;
/**
* The parameter of `eliminate_dead_code`
*/
static mds_kbdc_parsed_t* restrict result;
/**
* The original value of `result->pathname`
*/
static char* original_pathname;
/**
* The original value of `result->source_code`
*/
static mds_kbdc_source_code_t* original_source_code;
/**
* Stack of visited include-statements
*/
static mds_kbdc_tree_include_t** restrict includes = NULL;
/**
* The number elements allocated for `includes`
*/
static size_t includes_size = 0;
/**
* The number elements stored in `includes`
*/
static size_t includes_ptr = 0;
/**
* Validate that a part of the structure of the compilation unit
*
* @param tree The tree to validate
* @return Zero on success, -1 on error
*/
static int eliminate_subtree(mds_kbdc_tree_t* restrict tree);
/**
* Add “included from here”-notes
*
* @param ptr The number of “included from here”-notes
* @return Zero on success, -1 on error
*/
static int dump_include_stack(size_t ptr)
{
char* old_pathname = result->pathname;
mds_kbdc_source_code_t* old_source_code = result->source_code;
while (ptr--)
{
result->pathname = ptr ? includes[ptr - 1]->filename : original_pathname;
result->source_code = ptr ? includes[ptr - 1]->source_code : original_source_code;
NEW_ERROR(includes[ptr], NOTE, "included from here");
}
result->pathname = old_pathname;
result->source_code = old_source_code;
return 0;
pfail:
result->pathname = old_pathname;
result->source_code = old_source_code;
return -1;
}
/**
* Eliminate dead code in an include-statement
*
* @param tree The tree to reduce
* @return Zero on success, -1 on error
*/
static int eliminate_include(mds_kbdc_tree_include_t* restrict tree)
{
mds_kbdc_tree_include_t** old;
char* pathname = result->pathname;
mds_kbdc_source_code_t* source_code = result->source_code;
int r, saved_errno;
if (includes_ptr == includes_size)
if (xxrealloc(old, includes, includes_size += 4, mds_kbdc_tree_include_t*))
return saved_errno = errno, free(old), errno = saved_errno, -1;
includes[includes_ptr++] = tree;
result->pathname = tree->filename;
result->source_code = tree->source_code;
r = eliminate_subtree(tree->inner);
result->pathname = pathname;
result->source_code = source_code;
return includes_ptr--, r;
}
/**
* Eliminate dead code in a subtree
*
* @param tree The tree to reduce
* @return Zero on success, -1 on error
*/
static int eliminate_subtree(mds_kbdc_tree_t* restrict tree)
{
#define e(type) if ((r = eliminate_##type(&(tree->type)))) return r
#define E(type) if ((r = eliminate_##type(&(tree->type##_)))) return r
int r;
again:
if (tree == NULL)
return 0;
switch (tree->type)
{
case C(INCLUDE): e(include); break;
default:
break;
}
tree = tree->next;
goto again;
#undef E
#undef e
}
/**
* Eliminate and warn about dead code
*
* @param result_ `result` from `validate_tree`, will be updated
* @return -1 if an error occursed that cannot be stored in `result`, zero otherwise
*/
int eliminate_dead_code(mds_kbdc_parsed_t* restrict result_)
{
int r, saved_errno;
result = result_;
original_pathname = result_->pathname;
original_source_code = result_->source_code;
r = eliminate_subtree(result_->tree);
saved_errno = errno;
result_->pathname = original_pathname;
result_->source_code = original_source_code;
free(includes), includes = NULL;
includes_size = includes_ptr = 0;
return errno = saved_errno, r;
}
#undef NEW_ERROR_WITH_INCLUDES
#undef DUMP_INCLUDE_STACK
#undef NEW_ERROR
#undef C
