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Diffstat (limited to 'gdb/macroexp.c')
| -rw-r--r-- | gdb/macroexp.c | 1169 |
1 files changed, 1169 insertions, 0 deletions
diff --git a/gdb/macroexp.c b/gdb/macroexp.c new file mode 100644 index 0000000..cb97f42 --- /dev/null +++ b/gdb/macroexp.c @@ -0,0 +1,1169 @@ +/* C preprocessor macro expansion for GDB. + Copyright 2002 Free Software Foundation, Inc. + Contributed by Red Hat, Inc. + + This file is part of GDB. + + 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 2 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, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include "defs.h" +#include "obstack.h" +#include "bcache.h" +#include "macrotab.h" +#include "macroexp.h" +#include "gdb_assert.h" + + + +/* A resizeable, substringable string type. */ + + +/* A string type that we can resize, quickly append to, and use to + refer to substrings of other strings. */ +struct macro_buffer +{ + /* An array of characters. The first LEN bytes are the real text, + but there are SIZE bytes allocated to the array. If SIZE is + zero, then this doesn't point to a malloc'ed block. If SHARED is + non-zero, then this buffer is actually a pointer into some larger + string, and we shouldn't append characters to it, etc. Because + of sharing, we can't assume in general that the text is + null-terminated. */ + char *text; + + /* The number of characters in the string. */ + int len; + + /* The number of characters allocated to the string. If SHARED is + non-zero, this is meaningless; in this case, we set it to zero so + that any "do we have room to append something?" tests will fail, + so we don't always have to check SHARED before using this field. */ + int size; + + /* Zero if TEXT can be safely realloc'ed (i.e., it's its own malloc + block). Non-zero if TEXT is actually pointing into the middle of + some other block, and we shouldn't reallocate it. */ + int shared; + + /* For detecting token splicing. + + This is the index in TEXT of the first character of the token + that abuts the end of TEXT. If TEXT contains no tokens, then we + set this equal to LEN. If TEXT ends in whitespace, then there is + no token abutting the end of TEXT (it's just whitespace), and + again, we set this equal to LEN. We set this to -1 if we don't + know the nature of TEXT. */ + int last_token; + + /* If this buffer is holding the result from get_token, then this + is non-zero if it is an identifier token, zero otherwise. */ + int is_identifier; +}; + + +/* Set the macro buffer *B to the empty string, guessing that its + final contents will fit in N bytes. (It'll get resized if it + doesn't, so the guess doesn't have to be right.) Allocate the + initial storage with xmalloc. */ +static void +init_buffer (struct macro_buffer *b, int n) +{ + /* Small value for initial testing. */ + n = 1; + + b->size = n; + if (n > 0) + b->text = (char *) xmalloc (n); + else + b->text = 0; + b->len = 0; + b->shared = 0; + b->last_token = -1; +} + + +/* Set the macro buffer *BUF to refer to the LEN bytes at ADDR, as a + shared substring. */ +static void +init_shared_buffer (struct macro_buffer *buf, char *addr, int len) +{ + buf->text = addr; + buf->len = len; + buf->shared = 1; + buf->size = 0; + buf->last_token = -1; +} + + +/* Free the text of the buffer B. Raise an error if B is shared. */ +static void +free_buffer (struct macro_buffer *b) +{ + gdb_assert (! b->shared); + if (b->size) + xfree (b->text); +} + + +/* A cleanup function for macro buffers. */ +static void +cleanup_macro_buffer (void *untyped_buf) +{ + free_buffer ((struct macro_buffer *) untyped_buf); +} + + +/* Resize the buffer B to be at least N bytes long. Raise an error if + B shouldn't be resized. */ +static void +resize_buffer (struct macro_buffer *b, int n) +{ + /* We shouldn't be trying to resize shared strings. */ + gdb_assert (! b->shared); + + if (b->size == 0) + b->size = n; + else + while (b->size <= n) + b->size *= 2; + + b->text = xrealloc (b->text, b->size); +} + + +/* Append the character C to the buffer B. */ +static inline void +appendc (struct macro_buffer *b, int c) +{ + int new_len = b->len + 1; + + if (new_len > b->size) + resize_buffer (b, new_len); + + b->text[b->len] = c; + b->len = new_len; +} + + +/* Append the LEN bytes at ADDR to the buffer B. */ +static inline void +appendmem (struct macro_buffer *b, char *addr, int len) +{ + int new_len = b->len + len; + + if (new_len > b->size) + resize_buffer (b, new_len); + + memcpy (b->text + b->len, addr, len); + b->len = new_len; +} + + + +/* Recognizing preprocessor tokens. */ + + +static int +is_whitespace (int c) +{ + return (c == ' ' + || c == '\t' + || c == '\n' + || c == '\v' + || c == '\f'); +} + + +static int +is_digit (int c) +{ + return ('0' <= c && c <= '9'); +} + + +static int +is_identifier_nondigit (int c) +{ + return (c == '_' + || ('a' <= c && c <= 'z') + || ('A' <= c && c <= 'Z')); +} + + +static void +set_token (struct macro_buffer *tok, char *start, char *end) +{ + init_shared_buffer (tok, start, end - start); + tok->last_token = 0; + + /* Presumed; get_identifier may overwrite this. */ + tok->is_identifier = 0; +} + + +static int +get_comment (struct macro_buffer *tok, char *p, char *end) +{ + if (p + 2 > end) + return 0; + else if (p[0] == '/' + && p[1] == '*') + { + char *tok_start = p; + + p += 2; + + for (; p < end; p++) + if (p + 2 <= end + && p[0] == '*' + && p[1] == '/') + { + p += 2; + set_token (tok, tok_start, p); + return 1; + } + + error ("Unterminated comment in macro expansion."); + } + else if (p[0] == '/' + && p[1] == '/') + { + char *tok_start = p; + + p += 2; + for (; p < end; p++) + if (*p == '\n') + break; + + set_token (tok, tok_start, p); + return 1; + } + else + return 0; +} + + +static int +get_identifier (struct macro_buffer *tok, char *p, char *end) +{ + if (p < end + && is_identifier_nondigit (*p)) + { + char *tok_start = p; + + while (p < end + && (is_identifier_nondigit (*p) + || is_digit (*p))) + p++; + + set_token (tok, tok_start, p); + tok->is_identifier = 1; + return 1; + } + else + return 0; +} + + +static int +get_pp_number (struct macro_buffer *tok, char *p, char *end) +{ + if (p < end + && (is_digit (*p) + || *p == '.')) + { + char *tok_start = p; + + while (p < end) + { + if (is_digit (*p) + || is_identifier_nondigit (*p) + || *p == '.') + p++; + else if (p + 2 <= end + && strchr ("eEpP.", *p) + && (p[1] == '+' || p[1] == '-')) + p += 2; + else + break; + } + + set_token (tok, tok_start, p); + return 1; + } + else + return 0; +} + + + +/* If the text starting at P going up to (but not including) END + starts with a character constant, set *TOK to point to that + character constant, and return 1. Otherwise, return zero. + Signal an error if it contains a malformed or incomplete character + constant. */ +static int +get_character_constant (struct macro_buffer *tok, char *p, char *end) +{ + /* ISO/IEC 9899:1999 (E) Section 6.4.4.4 paragraph 1 + But of course, what really matters is that we handle it the same + way GDB's C/C++ lexer does. So we call parse_escape in utils.c + to handle escape sequences. */ + if ((p + 1 <= end && *p == '\'') + || (p + 2 <= end && p[0] == 'L' && p[1] == '\'')) + { + char *tok_start = p; + char *body_start; + + if (*p == '\'') + p++; + else if (*p == 'L') + p += 2; + else + gdb_assert (0); + + body_start = p; + for (;;) + { + if (p >= end) + error ("Unmatched single quote."); + else if (*p == '\'') + { + if (p == body_start) + error ("A character constant must contain at least one " + "character."); + p++; + break; + } + else if (*p == '\\') + { + p++; + parse_escape (&p); + } + else + p++; + } + + set_token (tok, tok_start, p); + return 1; + } + else + return 0; +} + + +/* If the text starting at P going up to (but not including) END + starts with a string literal, set *TOK to point to that string + literal, and return 1. Otherwise, return zero. Signal an error if + it contains a malformed or incomplete string literal. */ +static int +get_string_literal (struct macro_buffer *tok, char *p, char *end) +{ + if ((p + 1 <= end + && *p == '\"') + || (p + 2 <= end + && p[0] == 'L' + && p[1] == '\"')) + { + char *tok_start = p; + + if (*p == '\"') + p++; + else if (*p == 'L') + p += 2; + else + gdb_assert (0); + + for (;;) + { + if (p >= end) + error ("Unterminated string in expression."); + else if (*p == '\"') + { + p++; + break; + } + else if (*p == '\n') + error ("Newline characters may not appear in string " + "constants."); + else if (*p == '\\') + { + p++; + parse_escape (&p); + } + else + p++; + } + + set_token (tok, tok_start, p); + return 1; + } + else + return 0; +} + + +static int +get_punctuator (struct macro_buffer *tok, char *p, char *end) +{ + /* Here, speed is much less important than correctness and clarity. */ + + /* ISO/IEC 9899:1999 (E) Section 6.4.6 Paragraph 1 */ + static const char * const punctuators[] = { + "[", "]", "(", ")", "{", "}", ".", "->", + "++", "--", "&", "*", "+", "-", "~", "!", + "/", "%", "<<", ">>", "<", ">", "<=", ">=", "==", "!=", + "^", "|", "&&", "||", + "?", ":", ";", "...", + "=", "*=", "/=", "%=", "+=", "-=", "<<=", ">>=", "&=", "^=", "|=", + ",", "#", "##", + "<:", ":>", "<%", "%>", "%:", "%:%:", + 0 + }; + + int i; + + if (p + 1 <= end) + { + for (i = 0; punctuators[i]; i++) + { + const char *punctuator = punctuators[i]; + + if (p[0] == punctuator[0]) + { + int len = strlen (punctuator); + + if (p + len <= end + && ! memcmp (p, punctuator, len)) + { + set_token (tok, p, p + len); + return 1; + } + } + } + } + + return 0; +} + + +/* Peel the next preprocessor token off of SRC, and put it in TOK. + Mutate TOK to refer to the first token in SRC, and mutate SRC to + refer to the text after that token. SRC must be a shared buffer; + the resulting TOK will be shared, pointing into the same string SRC + does. Initialize TOK's last_token field. Return non-zero if we + succeed, or 0 if we didn't find any more tokens in SRC. */ +static int +get_token (struct macro_buffer *tok, + struct macro_buffer *src) +{ + char *p = src->text; + char *end = p + src->len; + + gdb_assert (src->shared); + + /* From the ISO C standard, ISO/IEC 9899:1999 (E), section 6.4: + + preprocessing-token: + header-name + identifier + pp-number + character-constant + string-literal + punctuator + each non-white-space character that cannot be one of the above + + We don't have to deal with header-name tokens, since those can + only occur after a #include, which we will never see. */ + + while (p < end) + if (is_whitespace (*p)) + p++; + else if (get_comment (tok, p, end)) + p += tok->len; + else if (get_pp_number (tok, p, end) + || get_character_constant (tok, p, end) + || get_string_literal (tok, p, end) + /* Note: the grammar in the standard seems to be + ambiguous: L'x' can be either a wide character + constant, or an identifier followed by a normal + character constant. By trying `get_identifier' after + we try get_character_constant and get_string_literal, + we give the wide character syntax precedence. Now, + since GDB doesn't handle wide character constants + anyway, is this the right thing to do? */ + || get_identifier (tok, p, end) + || get_punctuator (tok, p, end)) + { + /* How many characters did we consume, including whitespace? */ + int consumed = p - src->text + tok->len; + src->text += consumed; + src->len -= consumed; + return 1; + } + else + { + /* We have found a "non-whitespace character that cannot be + one of the above." Make a token out of it. */ + int consumed; + + set_token (tok, p, p + 1); + consumed = p - src->text + tok->len; + src->text += consumed; + src->len -= consumed; + return 1; + } + + return 0; +} + + + +/* Appending token strings, with and without splicing */ + + +/* Append the macro buffer SRC to the end of DEST, and ensure that + doing so doesn't splice the token at the end of SRC with the token + at the beginning of DEST. SRC and DEST must have their last_token + fields set. Upon return, DEST's last_token field is set correctly. + + For example: + + If DEST is "(" and SRC is "y", then we can return with + DEST set to "(y" --- we've simply appended the two buffers. + + However, if DEST is "x" and SRC is "y", then we must not return + with DEST set to "xy" --- that would splice the two tokens "x" and + "y" together to make a single token "xy". However, it would be + fine to return with DEST set to "x y". Similarly, "<" and "<" must + yield "< <", not "<<", etc. */ +static void +append_tokens_without_splicing (struct macro_buffer *dest, + struct macro_buffer *src) +{ + int original_dest_len = dest->len; + struct macro_buffer dest_tail, new_token; + + gdb_assert (src->last_token != -1); + gdb_assert (dest->last_token != -1); + + /* First, just try appending the two, and call get_token to see if + we got a splice. */ + appendmem (dest, src->text, src->len); + + /* If DEST originally had no token abutting its end, then we can't + have spliced anything, so we're done. */ + if (dest->last_token == original_dest_len) + { + dest->last_token = original_dest_len + src->last_token; + return; + } + + /* Set DEST_TAIL to point to the last token in DEST, followed by + all the stuff we just appended. */ + init_shared_buffer (&dest_tail, + dest->text + dest->last_token, + dest->len - dest->last_token); + + /* Re-parse DEST's last token. We know that DEST used to contain + at least one token, so if it doesn't contain any after the + append, then we must have spliced "/" and "*" or "/" and "/" to + make a comment start. (Just for the record, I got this right + the first time. This is not a bug fix.) */ + if (get_token (&new_token, &dest_tail) + && (new_token.text + new_token.len + == dest->text + original_dest_len)) + { + /* No splice, so we're done. */ + dest->last_token = original_dest_len + src->last_token; + return; + } + + /* Okay, a simple append caused a splice. Let's chop dest back to + its original length and try again, but separate the texts with a + space. */ + dest->len = original_dest_len; + appendc (dest, ' '); + appendmem (dest, src->text, src->len); + + init_shared_buffer (&dest_tail, + dest->text + dest->last_token, + dest->len - dest->last_token); + + /* Try to re-parse DEST's last token, as above. */ + if (get_token (&new_token, &dest_tail) + && (new_token.text + new_token.len + == dest->text + original_dest_len)) + { + /* No splice, so we're done. */ + dest->last_token = original_dest_len + 1 + src->last_token; + return; + } + + /* As far as I know, there's no case where inserting a space isn't + enough to prevent a splice. */ + internal_error (__FILE__, __LINE__, + "unable to avoid splicing tokens during macro expansion"); +} + + + +/* Expanding macros! */ + + +/* A singly-linked list of the names of the macros we are currently + expanding --- for detecting expansion loops. */ +struct macro_name_list { + const char *name; + struct macro_name_list *next; +}; + + +/* Return non-zero if we are currently expanding the macro named NAME, + according to LIST; otherwise, return zero. + + You know, it would be possible to get rid of all the NO_LOOP + arguments to these functions by simply generating a new lookup + function and baton which refuses to find the definition for a + particular macro, and otherwise delegates the decision to another + function/baton pair. But that makes the linked list of excluded + macros chained through untyped baton pointers, which will make it + harder to debug. :( */ +static int +currently_rescanning (struct macro_name_list *list, const char *name) +{ + for (; list; list = list->next) + if (! strcmp (name, list->name)) + return 1; + + return 0; +} + + +/* Gather the arguments to a macro expansion. + + NAME is the name of the macro being invoked. (It's only used for + printing error messages.) + + Assume that SRC is the text of the macro invocation immediately + following the macro name. For example, if we're processing the + text foo(bar, baz), then NAME would be foo and SRC will be (bar, + baz). + + If SRC doesn't start with an open paren ( token at all, return + zero, leave SRC unchanged, and don't set *ARGC_P to anything. + + If SRC doesn't contain a properly terminated argument list, then + raise an error. + + Otherwise, return a pointer to the first element of an array of + macro buffers referring to the argument texts, and set *ARGC_P to + the number of arguments we found --- the number of elements in the + array. The macro buffers share their text with SRC, and their + last_token fields are initialized. The array is allocated with + xmalloc, and the caller is responsible for freeing it. + + NOTE WELL: if SRC starts with a open paren ( token followed + immediately by a close paren ) token (e.g., the invocation looks + like "foo()"), we treat that as one argument, which happens to be + the empty list of tokens. The caller should keep in mind that such + a sequence of tokens is a valid way to invoke one-parameter + function-like macros, but also a valid way to invoke zero-parameter + function-like macros. Eeew. + + Consume the tokens from SRC; after this call, SRC contains the text + following the invocation. */ + +static struct macro_buffer * +gather_arguments (const char *name, struct macro_buffer *src, int *argc_p) +{ + struct macro_buffer tok; + int args_len, args_size; + struct macro_buffer *args = 0; + struct cleanup *back_to = make_cleanup (free_current_contents, &args); + + /* Does SRC start with an opening paren token? Read from a copy of + SRC, so SRC itself is unaffected if we don't find an opening + paren. */ + { + struct macro_buffer temp; + init_shared_buffer (&temp, src->text, src->len); + + if (! get_token (&tok, &temp) + || tok.len != 1 + || tok.text[0] != '(') + { + discard_cleanups (back_to); + return 0; + } + } + + /* Consume SRC's opening paren. */ + get_token (&tok, src); + + args_len = 0; + args_size = 1; /* small for initial testing */ + args = (struct macro_buffer *) xmalloc (sizeof (*args) * args_size); + + for (;;) + { + struct macro_buffer *arg; + int depth; + + /* Make sure we have room for the next argument. */ + if (args_len >= args_size) + { + args_size *= 2; + args = xrealloc (args, sizeof (*args) * args_size); + } + + /* Initialize the next argument. */ + arg = &args[args_len++]; + set_token (arg, src->text, src->text); + + /* Gather the argument's tokens. */ + depth = 0; + for (;;) + { + char *start = src->text; + + if (! get_token (&tok, src)) + error ("Malformed argument list for macro `%s'.", name); + + /* Is tok an opening paren? */ + if (tok.len == 1 && tok.text[0] == '(') + depth++; + + /* Is tok is a closing paren? */ + else if (tok.len == 1 && tok.text[0] == ')') + { + /* If it's a closing paren at the top level, then that's + the end of the argument list. */ + if (depth == 0) + { + discard_cleanups (back_to); + *argc_p = args_len; + return args; + } + + depth--; + } + + /* If tok is a comma at top level, then that's the end of + the current argument. */ + else if (tok.len == 1 && tok.text[0] == ',' && depth == 0) + break; + + /* Extend the current argument to enclose this token. If + this is the current argument's first token, leave out any + leading whitespace, just for aesthetics. */ + if (arg->len == 0) + { + arg->text = tok.text; + arg->len = tok.len; + arg->last_token = 0; + } + else + { + arg->len = (tok.text + tok.len) - arg->text; + arg->last_token = tok.text - arg->text; + } + } + } +} + + +/* The `expand' and `substitute_args' functions both invoke `scan' + recursively, so we need a forward declaration somewhere. */ +static void scan (struct macro_buffer *dest, + struct macro_buffer *src, + struct macro_name_list *no_loop, + macro_lookup_ftype *lookup_func, + void *lookup_baton); + + +/* Given the macro definition DEF, being invoked with the actual + arguments given by ARGC and ARGV, substitute the arguments into the + replacement list, and store the result in DEST. + + If it is necessary to expand macro invocations in one of the + arguments, use LOOKUP_FUNC and LOOKUP_BATON to find the macro + definitions, and don't expand invocations of the macros listed in + NO_LOOP. */ +static void +substitute_args (struct macro_buffer *dest, + struct macro_definition *def, + int argc, struct macro_buffer *argv, + struct macro_name_list *no_loop, + macro_lookup_ftype *lookup_func, + void *lookup_baton) +{ + /* A macro buffer for the macro's replacement list. */ + struct macro_buffer replacement_list; + + init_shared_buffer (&replacement_list, (char *) def->replacement, + strlen (def->replacement)); + + gdb_assert (dest->len == 0); + dest->last_token = 0; + + for (;;) + { + struct macro_buffer tok; + char *original_rl_start = replacement_list.text; + int substituted = 0; + + /* Find the next token in the replacement list. */ + if (! get_token (&tok, &replacement_list)) + break; + + /* Just for aesthetics. If we skipped some whitespace, copy + that to DEST. */ + if (tok.text > original_rl_start) + { + appendmem (dest, original_rl_start, tok.text - original_rl_start); + dest->last_token = dest->len; + } + + /* Is this token the stringification operator? */ + if (tok.len == 1 + && tok.text[0] == '#') + error ("Stringification is not implemented yet."); + + /* Is this token the splicing operator? */ + if (tok.len == 2 + && tok.text[0] == '#' + && tok.text[1] == '#') + error ("Token splicing is not implemented yet."); + + /* Is this token an identifier? */ + if (tok.is_identifier) + { + int i; + + /* Is it the magic varargs parameter? */ + if (tok.len == 11 + && ! memcmp (tok.text, "__VA_ARGS__", 11)) + error ("Variable-arity macros not implemented yet."); + + /* Is it one of the parameters? */ + for (i = 0; i < def->argc; i++) + if (tok.len == strlen (def->argv[i]) + && ! memcmp (tok.text, def->argv[i], tok.len)) + { + struct macro_buffer arg_src; + + /* Expand any macro invocations in the argument text, + and append the result to dest. Remember that scan + mutates its source, so we need to scan a new buffer + referring to the argument's text, not the argument + itself. */ + init_shared_buffer (&arg_src, argv[i].text, argv[i].len); + scan (dest, &arg_src, no_loop, lookup_func, lookup_baton); + substituted = 1; + break; + } + } + + /* If it wasn't a parameter, then just copy it across. */ + if (! substituted) + append_tokens_without_splicing (dest, &tok); + } +} + + +/* Expand a call to a macro named ID, whose definition is DEF. Append + its expansion to DEST. SRC is the input text following the ID + token. We are currently rescanning the expansions of the macros + named in NO_LOOP; don't re-expand them. Use LOOKUP_FUNC and + LOOKUP_BATON to find definitions for any nested macro references. + + Return 1 if we decided to expand it, zero otherwise. (If it's a + function-like macro name that isn't followed by an argument list, + we don't expand it.) If we return zero, leave SRC unchanged. */ +static int +expand (const char *id, + struct macro_definition *def, + struct macro_buffer *dest, + struct macro_buffer *src, + struct macro_name_list *no_loop, + macro_lookup_ftype *lookup_func, + void *lookup_baton) +{ + struct macro_name_list new_no_loop; + + /* Create a new node to be added to the front of the no-expand list. + This list is appropriate for re-scanning replacement lists, but + it is *not* appropriate for scanning macro arguments; invocations + of the macro whose arguments we are gathering *do* get expanded + there. */ + new_no_loop.name = id; + new_no_loop.next = no_loop; + + /* What kind of macro are we expanding? */ + if (def->kind == macro_object_like) + { + struct macro_buffer replacement_list; + + init_shared_buffer (&replacement_list, (char *) def->replacement, + strlen (def->replacement)); + + scan (dest, &replacement_list, &new_no_loop, lookup_func, lookup_baton); + return 1; + } + else if (def->kind == macro_function_like) + { + struct cleanup *back_to = make_cleanup (null_cleanup, 0); + int argc; + struct macro_buffer *argv = 0; + struct macro_buffer substituted; + struct macro_buffer substituted_src; + + if (def->argc >= 1 + && ! strcmp (def->argv[def->argc - 1], "...")) + error ("Varargs macros not implemented yet."); + + make_cleanup (free_current_contents, &argv); + argv = gather_arguments (id, src, &argc); + + /* If we couldn't find any argument list, then we don't expand + this macro. */ + if (! argv) + { + do_cleanups (back_to); + return 0; + } + + /* Check that we're passing an acceptable number of arguments for + this macro. */ + if (argc != def->argc) + { + /* Remember that a sequence of tokens like "foo()" is a + valid invocation of a macro expecting either zero or one + arguments. */ + if (! (argc == 1 + && argv[0].len == 0 + && def->argc == 0)) + error ("Wrong number of arguments to macro `%s' " + "(expected %d, got %d).", + id, def->argc, argc); + } + + /* Note that we don't expand macro invocations in the arguments + yet --- we let subst_args take care of that. Parameters that + appear as operands of the stringifying operator "#" or the + splicing operator "##" don't get macro references expanded, + so we can't really tell whether it's appropriate to macro- + expand an argument until we see how it's being used. */ + init_buffer (&substituted, 0); + make_cleanup (cleanup_macro_buffer, &substituted); + substitute_args (&substituted, def, argc, argv, no_loop, + lookup_func, lookup_baton); + + /* Now `substituted' is the macro's replacement list, with all + argument values substituted into it properly. Re-scan it for + macro references, but don't expand invocations of this macro. + + We create a new buffer, `substituted_src', which points into + `substituted', and scan that. We can't scan `substituted' + itself, since the tokenization process moves the buffer's + text pointer around, and we still need to be able to find + `substituted's original text buffer after scanning it so we + can free it. */ + init_shared_buffer (&substituted_src, substituted.text, substituted.len); + scan (dest, &substituted_src, &new_no_loop, lookup_func, lookup_baton); + + do_cleanups (back_to); + + return 1; + } + else + internal_error (__FILE__, __LINE__, "bad macro definition kind"); +} + + +/* If the single token in SRC_FIRST followed by the tokens in SRC_REST + constitute a macro invokation not forbidden in NO_LOOP, append its + expansion to DEST and return non-zero. Otherwise, return zero, and + leave DEST unchanged. + + SRC_FIRST and SRC_REST must be shared buffers; DEST must not be one. + SRC_FIRST must be a string built by get_token. */ +static int +maybe_expand (struct macro_buffer *dest, + struct macro_buffer *src_first, + struct macro_buffer *src_rest, + struct macro_name_list *no_loop, + macro_lookup_ftype *lookup_func, + void *lookup_baton) +{ + gdb_assert (src_first->shared); + gdb_assert (src_rest->shared); + gdb_assert (! dest->shared); + + /* Is this token an identifier? */ + if (src_first->is_identifier) + { + /* Make a null-terminated copy of it, since that's what our + lookup function expects. */ + char *id = xmalloc (src_first->len + 1); + struct cleanup *back_to = make_cleanup (xfree, id); + memcpy (id, src_first->text, src_first->len); + id[src_first->len] = 0; + + /* If we're currently re-scanning the result of expanding + this macro, don't expand it again. */ + if (! currently_rescanning (no_loop, id)) + { + /* Does this identifier have a macro definition in scope? */ + struct macro_definition *def = lookup_func (id, lookup_baton); + + if (def && expand (id, def, dest, src_rest, no_loop, + lookup_func, lookup_baton)) + { + do_cleanups (back_to); + return 1; + } + } + + do_cleanups (back_to); + } + + return 0; +} + + +/* Expand macro references in SRC, appending the results to DEST. + Assume we are re-scanning the result of expanding the macros named + in NO_LOOP, and don't try to re-expand references to them. + + SRC must be a shared buffer; DEST must not be one. */ +static void +scan (struct macro_buffer *dest, + struct macro_buffer *src, + struct macro_name_list *no_loop, + macro_lookup_ftype *lookup_func, + void *lookup_baton) +{ + gdb_assert (src->shared); + gdb_assert (! dest->shared); + + for (;;) + { + struct macro_buffer tok; + char *original_src_start = src->text; + + /* Find the next token in SRC. */ + if (! get_token (&tok, src)) + break; + + /* Just for aesthetics. If we skipped some whitespace, copy + that to DEST. */ + if (tok.text > original_src_start) + { + appendmem (dest, original_src_start, tok.text - original_src_start); + dest->last_token = dest->len; + } + + if (! maybe_expand (dest, &tok, src, no_loop, lookup_func, lookup_baton)) + /* We didn't end up expanding tok as a macro reference, so + simply append it to dest. */ + append_tokens_without_splicing (dest, &tok); + } + + /* Just for aesthetics. If there was any trailing whitespace in + src, copy it to dest. */ + if (src->len) + { + appendmem (dest, src->text, src->len); + dest->last_token = dest->len; + } +} + + +char * +macro_expand (const char *source, + macro_lookup_ftype *lookup_func, + void *lookup_func_baton) +{ + struct macro_buffer src, dest; + struct cleanup *back_to; + + init_shared_buffer (&src, (char *) source, strlen (source)); + + init_buffer (&dest, 0); + dest.last_token = 0; + back_to = make_cleanup (cleanup_macro_buffer, &dest); + + scan (&dest, &src, 0, lookup_func, lookup_func_baton); + + appendc (&dest, '\0'); + + discard_cleanups (back_to); + return dest.text; +} + + +char * +macro_expand_once (const char *source, + macro_lookup_ftype *lookup_func, + void *lookup_func_baton) +{ + error ("Expand-once not implemented yet."); +} + + +char * +macro_expand_next (char **lexptr, + macro_lookup_ftype *lookup_func, + void *lookup_baton) +{ + struct macro_buffer src, dest, tok; + struct cleanup *back_to; + + /* Set up SRC to refer to the input text, pointed to by *lexptr. */ + init_shared_buffer (&src, *lexptr, strlen (*lexptr)); + + /* Set up DEST to receive the expansion, if there is one. */ + init_buffer (&dest, 0); + dest.last_token = 0; + back_to = make_cleanup (cleanup_macro_buffer, &dest); + + /* Get the text's first preprocessing token. */ + if (! get_token (&tok, &src)) + { + do_cleanups (back_to); + return 0; + } + + /* If it's a macro invocation, expand it. */ + if (maybe_expand (&dest, &tok, &src, 0, lookup_func, lookup_baton)) + { + /* It was a macro invocation! Package up the expansion as a + null-terminated string and return it. Set *lexptr to the + start of the next token in the input. */ + appendc (&dest, '\0'); + discard_cleanups (back_to); + *lexptr = src.text; + return dest.text; + } + else + { + /* It wasn't a macro invocation. */ + do_cleanups (back_to); + return 0; + } +} |