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Diffstat (limited to 'src/mds-kbdc/eliminate-dead-code.c')
| -rw-r--r-- | src/mds-kbdc/eliminate-dead-code.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/src/mds-kbdc/eliminate-dead-code.c b/src/mds-kbdc/eliminate-dead-code.c new file mode 100644 index 0000000..495cbb5 --- /dev/null +++ b/src/mds-kbdc/eliminate-dead-code.c @@ -0,0 +1,224 @@ +/** + * 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 + + |