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Diffstat (limited to 'src/macro.c')
| -rw-r--r-- | src/macro.c | 391 |
1 files changed, 391 insertions, 0 deletions
diff --git a/src/macro.c b/src/macro.c new file mode 100644 index 0000000..0e76243 --- /dev/null +++ b/src/macro.c @@ -0,0 +1,391 @@ +/* GNU m4 -- A simple macro processor + + Copyright (C) 1989-1994, 2006-2007, 2009-2013 Free Software + Foundation, Inc. + + This file is part of GNU M4. + + GNU M4 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. + + GNU M4 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/>. +*/ + +/* This file contains the functions, that performs the basic argument + parsing and macro expansion. */ + +#include "m4.h" + +static void expand_macro (symbol *); +static void expand_token (struct obstack *, token_type, token_data *, int); + +/* Current recursion level in expand_macro (). */ +int expansion_level = 0; + +/* The number of the current call of expand_macro (). */ +static int macro_call_id = 0; + +/* The shared stack of collected arguments for macro calls; as each + argument is collected, it is finished and its location stored in + argv_stack. Normally, this stack can be used simultaneously by + multiple macro calls; the exception is when an outer macro has + generated some text, then calls a nested macro, in which case the + nested macro must use a local stack to leave the unfinished text + alone. Too bad obstack.h does not provide an easy way to reopen a + finished object for further growth, but in practice this does not + hurt us too much. */ +static struct obstack argc_stack; + +/* The shared stack of pointers to collected arguments for macro + calls. This object is never finished; we exploit the fact that + obstack_blank is documented to take a negative size to reduce the + size again. */ +static struct obstack argv_stack; + +/*----------------------------------------------------------------------. +| This function read all input, and expands each token, one at a time. | +`----------------------------------------------------------------------*/ + +void +expand_input (void) +{ + token_type t; + token_data td; + int line; + + obstack_init (&argc_stack); + obstack_init (&argv_stack); + + while ((t = next_token (&td, &line)) != TOKEN_EOF) + expand_token ((struct obstack *) NULL, t, &td, line); + + obstack_free (&argc_stack, NULL); + obstack_free (&argv_stack, NULL); +} + + +/*----------------------------------------------------------------. +| Expand one token, according to its type. Potential macro names | +| (TOKEN_WORD) are looked up in the symbol table, to see if they | +| have a macro definition. If they have, they are expanded as | +| macros, otherwise the text is just copied to the output. | +`----------------------------------------------------------------*/ + +static void +expand_token (struct obstack *obs, token_type t, token_data *td, int line) +{ + symbol *sym; + + switch (t) + { /* TOKSW */ + case TOKEN_EOF: + case TOKEN_MACDEF: + break; + + case TOKEN_OPEN: + case TOKEN_COMMA: + case TOKEN_CLOSE: + case TOKEN_SIMPLE: + case TOKEN_STRING: + shipout_text (obs, TOKEN_DATA_TEXT (td), strlen (TOKEN_DATA_TEXT (td)), + line); + break; + + case TOKEN_WORD: + sym = lookup_symbol (TOKEN_DATA_TEXT (td), SYMBOL_LOOKUP); + if (sym == NULL || SYMBOL_TYPE (sym) == TOKEN_VOID + || (SYMBOL_TYPE (sym) == TOKEN_FUNC + && SYMBOL_BLIND_NO_ARGS (sym) + && peek_token () != TOKEN_OPEN)) + { +#ifdef ENABLE_CHANGEWORD + shipout_text (obs, TOKEN_DATA_ORIG_TEXT (td), + strlen (TOKEN_DATA_ORIG_TEXT (td)), line); +#else + shipout_text (obs, TOKEN_DATA_TEXT (td), + strlen (TOKEN_DATA_TEXT (td)), line); +#endif + } + else + expand_macro (sym); + break; + + default: + M4ERROR ((warning_status, 0, + "INTERNAL ERROR: bad token type in expand_token ()")); + abort (); + } +} + + +/*-------------------------------------------------------------------. +| This function parses one argument to a macro call. It expects the | +| first left parenthesis, or the separating comma, to have been read | +| by the caller. It skips leading whitespace, and reads and expands | +| tokens, until it finds a comma or an right parenthesis at the same | +| level of parentheses. It returns a flag indicating whether the | +| argument read is the last for the active macro call. The argument | +| is built on the obstack OBS, indirectly through expand_token (). | +`-------------------------------------------------------------------*/ + +static bool +expand_argument (struct obstack *obs, token_data *argp) +{ + token_type t; + token_data td; + char *text; + int paren_level; + const char *file = current_file; + int line = current_line; + + TOKEN_DATA_TYPE (argp) = TOKEN_VOID; + + /* Skip leading white space. */ + do + { + t = next_token (&td, NULL); + } + while (t == TOKEN_SIMPLE && isspace (to_uchar (*TOKEN_DATA_TEXT (&td)))); + + paren_level = 0; + + while (1) + { + + switch (t) + { /* TOKSW */ + case TOKEN_COMMA: + case TOKEN_CLOSE: + if (paren_level == 0) + { + /* The argument MUST be finished, whether we want it or not. */ + obstack_1grow (obs, '\0'); + text = (char *) obstack_finish (obs); + + if (TOKEN_DATA_TYPE (argp) == TOKEN_VOID) + { + TOKEN_DATA_TYPE (argp) = TOKEN_TEXT; + TOKEN_DATA_TEXT (argp) = text; + } + return t == TOKEN_COMMA; + } + /* fallthru */ + case TOKEN_OPEN: + case TOKEN_SIMPLE: + text = TOKEN_DATA_TEXT (&td); + + if (*text == '(') + paren_level++; + else if (*text == ')') + paren_level--; + expand_token (obs, t, &td, line); + break; + + case TOKEN_EOF: + /* current_file changed to "" if we see TOKEN_EOF, use the + previous value we stored earlier. */ + M4ERROR_AT_LINE ((EXIT_FAILURE, 0, file, line, + "ERROR: end of file in argument list")); + break; + + case TOKEN_WORD: + case TOKEN_STRING: + expand_token (obs, t, &td, line); + break; + + case TOKEN_MACDEF: + if (obstack_object_size (obs) == 0) + { + TOKEN_DATA_TYPE (argp) = TOKEN_FUNC; + TOKEN_DATA_FUNC (argp) = TOKEN_DATA_FUNC (&td); + } + break; + + default: + M4ERROR ((warning_status, 0, + "INTERNAL ERROR: bad token type in expand_argument ()")); + abort (); + } + + t = next_token (&td, NULL); + } +} + +/*-------------------------------------------------------------. +| Collect all the arguments to a call of the macro SYM. The | +| arguments are stored on the obstack ARGUMENTS and a table of | +| pointers to the arguments on the obstack ARGPTR. | +`-------------------------------------------------------------*/ + +static void +collect_arguments (symbol *sym, struct obstack *argptr, + struct obstack *arguments) +{ + token_data td; + token_data *tdp; + bool more_args; + bool groks_macro_args = SYMBOL_MACRO_ARGS (sym); + + TOKEN_DATA_TYPE (&td) = TOKEN_TEXT; + TOKEN_DATA_TEXT (&td) = SYMBOL_NAME (sym); + tdp = (token_data *) obstack_copy (arguments, &td, sizeof td); + obstack_ptr_grow (argptr, tdp); + + if (peek_token () == TOKEN_OPEN) + { + next_token (&td, NULL); /* gobble parenthesis */ + do + { + more_args = expand_argument (arguments, &td); + + if (!groks_macro_args && TOKEN_DATA_TYPE (&td) == TOKEN_FUNC) + { + TOKEN_DATA_TYPE (&td) = TOKEN_TEXT; + TOKEN_DATA_TEXT (&td) = (char *) ""; + } + tdp = (token_data *) obstack_copy (arguments, &td, sizeof td); + obstack_ptr_grow (argptr, tdp); + } + while (more_args); + } +} + + +/*-------------------------------------------------------------------. +| The actual call of a macro is handled by call_macro (). | +| call_macro () is passed a symbol SYM, whose type is used to call | +| either a builtin function, or the user macro expansion function | +| expand_user_macro () (lives in builtin.c). There are ARGC | +| arguments to the call, stored in the ARGV table. The expansion is | +| left on the obstack EXPANSION. Macro tracing is also handled | +| here. | +`-------------------------------------------------------------------*/ + +void +call_macro (symbol *sym, int argc, token_data **argv, + struct obstack *expansion) +{ + switch (SYMBOL_TYPE (sym)) + { + case TOKEN_FUNC: + (*SYMBOL_FUNC (sym)) (expansion, argc, argv); + break; + + case TOKEN_TEXT: + expand_user_macro (expansion, sym, argc, argv); + break; + + case TOKEN_VOID: + default: + M4ERROR ((warning_status, 0, + "INTERNAL ERROR: bad symbol type in call_macro ()")); + abort (); + } +} + +/*-------------------------------------------------------------------. +| The macro expansion is handled by expand_macro (). It parses the | +| arguments, using collect_arguments (), and builds a table of | +| pointers to the arguments. The arguments themselves are stored on | +| a local obstack. Expand_macro () uses call_macro () to do the | +| call of the macro. | +| | +| Expand_macro () is potentially recursive, since it calls | +| expand_argument (), which might call expand_token (), which might | +| call expand_macro (). | +`-------------------------------------------------------------------*/ + +static void +expand_macro (symbol *sym) +{ + struct obstack arguments; /* Alternate obstack if argc_stack is busy. */ + unsigned argv_base; /* Size of argv_stack on entry. */ + bool use_argc_stack = true; /* Whether argc_stack is safe. */ + token_data **argv; + int argc; + struct obstack *expansion; + const char *expanded; + bool traced; + int my_call_id; + + /* Report errors at the location where the open parenthesis (if any) + was found, but after expansion, restore global state back to the + location of the close parenthesis. This is safe since we + guarantee that macro expansion does not alter the state of + current_file/current_line (dnl, include, and sinclude are special + cased in the input engine to ensure this fact). */ + const char *loc_open_file = current_file; + int loc_open_line = current_line; + const char *loc_close_file; + int loc_close_line; + + SYMBOL_PENDING_EXPANSIONS (sym)++; + expansion_level++; + if (nesting_limit > 0 && expansion_level > nesting_limit) + M4ERROR ((EXIT_FAILURE, 0, + "recursion limit of %d exceeded, use -L<N> to change it", + nesting_limit)); + + macro_call_id++; + my_call_id = macro_call_id; + + traced = (debug_level & DEBUG_TRACE_ALL) || SYMBOL_TRACED (sym); + + argv_base = obstack_object_size (&argv_stack); + if (obstack_object_size (&argc_stack) > 0) + { + /* We cannot use argc_stack if this is a nested invocation, and an + outer invocation has an unfinished argument being + collected. */ + obstack_init (&arguments); + use_argc_stack = false; + } + + if (traced && (debug_level & DEBUG_TRACE_CALL)) + trace_prepre (SYMBOL_NAME (sym), my_call_id); + + collect_arguments (sym, &argv_stack, + use_argc_stack ? &argc_stack : &arguments); + + argc = ((obstack_object_size (&argv_stack) - argv_base) + / sizeof (token_data *)); + argv = (token_data **) ((char *) obstack_base (&argv_stack) + argv_base); + + loc_close_file = current_file; + loc_close_line = current_line; + current_file = loc_open_file; + current_line = loc_open_line; + + if (traced) + trace_pre (SYMBOL_NAME (sym), my_call_id, argc, argv); + + expansion = push_string_init (); + call_macro (sym, argc, argv, expansion); + expanded = push_string_finish (); + + if (traced) + trace_post (SYMBOL_NAME (sym), my_call_id, argc, expanded); + + current_file = loc_close_file; + current_line = loc_close_line; + + --expansion_level; + --SYMBOL_PENDING_EXPANSIONS (sym); + + if (SYMBOL_DELETED (sym)) + free_symbol (sym); + + if (use_argc_stack) + obstack_free (&argc_stack, argv[0]); + else + obstack_free (&arguments, NULL); + obstack_blank (&argv_stack, -argc * sizeof (token_data *)); +} |