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- /* C preprocessor macro expansion for GDB.
- Copyright (C) 2002-2022 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 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 "defs.h"
- #include "gdbsupport/gdb_obstack.h"
- #include "macrotab.h"
- #include "macroexp.h"
- #include "macroscope.h"
- #include "c-lang.h"
- /* A string type that we can use to refer to substrings of other
- strings. */
- struct shared_macro_buffer
- {
- /* An array of characters. This buffer is a pointer into some
- larger string and thus we can't assume in that the text is
- null-terminated. */
- const char *text;
- /* The number of characters in the string. */
- int len;
- /* 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 = -1;
- /* 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 = 0;
- shared_macro_buffer ()
- : text (NULL),
- len (0)
- {
- }
- /* Set the macro buffer to refer to the LEN bytes at ADDR, as a
- shared substring. */
- shared_macro_buffer (const char *addr, int len)
- {
- set_shared (addr, len);
- }
- /* Set the macro buffer to refer to the LEN bytes at ADDR, as a
- shared substring. */
- void set_shared (const char *addr, int len_)
- {
- text = addr;
- len = len_;
- }
- };
- /* A string type that we can resize and quickly append to. */
- struct growable_macro_buffer
- {
- /* An array of characters. The first LEN bytes are the real text,
- but there are SIZE bytes allocated to the array. */
- char *text;
- /* The number of characters in the string. */
- int len;
- /* The number of characters allocated to the string. */
- int size;
- /* 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 = -1;
- /* Set the macro buffer 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. */
- explicit growable_macro_buffer (int n)
- : len (0),
- size (n)
- {
- if (n > 0)
- text = (char *) xmalloc (n);
- else
- text = NULL;
- }
- DISABLE_COPY_AND_ASSIGN (growable_macro_buffer);
- ~growable_macro_buffer ()
- {
- xfree (text);
- }
- /* Release the text of the buffer to the caller. */
- gdb::unique_xmalloc_ptr<char> release ()
- {
- gdb_assert (size);
- char *result = text;
- text = NULL;
- return gdb::unique_xmalloc_ptr<char> (result);
- }
- /* Resize the buffer to be at least N bytes long. */
- void resize_buffer (int n)
- {
- if (size == 0)
- size = n;
- else
- while (size <= n)
- size *= 2;
- text = (char *) xrealloc (text, size);
- }
- /* Append the character C to the buffer. */
- void appendc (int c)
- {
- int new_len = len + 1;
- if (new_len > size)
- resize_buffer (new_len);
- text[len] = c;
- len = new_len;
- }
- /* Append the COUNT bytes at ADDR to the buffer. */
- void appendmem (const char *addr, int count)
- {
- int new_len = len + count;
- if (new_len > size)
- resize_buffer (new_len);
- memcpy (text + len, addr, count);
- len = new_len;
- }
- };
- /* Recognizing preprocessor tokens. */
- int
- macro_is_whitespace (int c)
- {
- return (c == ' '
- || c == '\t'
- || c == '\n'
- || c == '\v'
- || c == '\f');
- }
- int
- macro_is_digit (int c)
- {
- return ('0' <= c && c <= '9');
- }
- int
- macro_is_identifier_nondigit (int c)
- {
- return (c == '_'
- || ('a' <= c && c <= 'z')
- || ('A' <= c && c <= 'Z'));
- }
- static void
- set_token (shared_macro_buffer *tok, const char *start, const char *end)
- {
- tok->set_shared (start, end - start);
- tok->last_token = 0;
- /* Presumed; get_identifier may overwrite this. */
- tok->is_identifier = 0;
- }
- static int
- get_comment (shared_macro_buffer *tok, const char *p, const char *end)
- {
- if (p + 2 > end)
- return 0;
- else if (p[0] == '/'
- && p[1] == '*')
- {
- const 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] == '/')
- {
- const 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 (shared_macro_buffer *tok, const char *p, const char *end)
- {
- if (p < end
- && macro_is_identifier_nondigit (*p))
- {
- const char *tok_start = p;
- while (p < end
- && (macro_is_identifier_nondigit (*p)
- || macro_is_digit (*p)))
- p++;
- set_token (tok, tok_start, p);
- tok->is_identifier = 1;
- return 1;
- }
- else
- return 0;
- }
- static int
- get_pp_number (shared_macro_buffer *tok, const char *p, const char *end)
- {
- if (p < end
- && (macro_is_digit (*p)
- || (*p == '.'
- && p + 2 <= end
- && macro_is_digit (p[1]))))
- {
- const char *tok_start = p;
- while (p < end)
- {
- if (p + 2 <= end
- && strchr ("eEpP", *p)
- && (p[1] == '+' || p[1] == '-'))
- p += 2;
- else if (macro_is_digit (*p)
- || macro_is_identifier_nondigit (*p)
- || *p == '.')
- p++;
- 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 (shared_macro_buffer *tok,
- const char *p, const 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[0] == 'u' || p[0] == 'U')
- && p[1] == '\''))
- {
- const char *tok_start = p;
- int char_count = 0;
- if (*p == '\'')
- p++;
- else if (*p == 'L' || *p == 'u' || *p == 'U')
- p += 2;
- else
- gdb_assert_not_reached ("unexpected character constant");
- for (;;)
- {
- if (p >= end)
- error (_("Unmatched single quote."));
- else if (*p == '\'')
- {
- if (!char_count)
- error (_("A character constant must contain at least one "
- "character."));
- p++;
- break;
- }
- else if (*p == '\\')
- {
- const char *s, *o;
- s = o = ++p;
- char_count += c_parse_escape (&s, NULL);
- p += s - o;
- }
- else
- {
- p++;
- char_count++;
- }
- }
- 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 (shared_macro_buffer *tok, const char *p, const char *end)
- {
- if ((p + 1 <= end
- && *p == '"')
- || (p + 2 <= end
- && (p[0] == 'L' || p[0] == 'u' || p[0] == 'U')
- && p[1] == '"'))
- {
- const char *tok_start = p;
- if (*p == '"')
- p++;
- else if (*p == 'L' || *p == 'u' || *p == 'U')
- p += 2;
- else
- gdb_assert_not_reached ("unexpected string literal");
- 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 == '\\')
- {
- const char *s, *o;
- s = o = ++p;
- c_parse_escape (&s, NULL);
- p += s - o;
- }
- else
- p++;
- }
- set_token (tok, tok_start, p);
- return 1;
- }
- else
- return 0;
- }
- static int
- get_punctuator (shared_macro_buffer *tok, const char *p, const char *end)
- {
- /* Here, speed is much less important than correctness and clarity. */
- /* ISO/IEC 9899:1999 (E) Section 6.4.6 Paragraph 1.
- Note that this table is ordered in a special way. A punctuator
- which is a prefix of another punctuator must appear after its
- "extension". Otherwise, the wrong token will be returned. */
- 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. The resulting TOK will point
- 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 (shared_macro_buffer *tok, shared_macro_buffer *src)
- {
- const char *p = src->text;
- const char *end = p + src->len;
- /* 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 (macro_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 (growable_macro_buffer *dest,
- shared_macro_buffer *src)
- {
- int original_dest_len = dest->len;
- shared_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. */
- dest->appendmem (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. */
- dest_tail.set_shared (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;
- dest->appendc (' ');
- dest->appendmem (src->text, src->len);
- dest_tail.set_shared (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"));
- }
- /* Stringify an argument, and insert it into DEST. ARG is the text to
- stringify; it is LEN bytes long. */
- static void
- stringify (growable_macro_buffer *dest, const char *arg, int len)
- {
- /* Trim initial whitespace from ARG. */
- while (len > 0 && macro_is_whitespace (*arg))
- {
- ++arg;
- --len;
- }
- /* Trim trailing whitespace from ARG. */
- while (len > 0 && macro_is_whitespace (arg[len - 1]))
- --len;
- /* Insert the string. */
- dest->appendc ('"');
- while (len > 0)
- {
- /* We could try to handle strange cases here, like control
- characters, but there doesn't seem to be much point. */
- if (macro_is_whitespace (*arg))
- {
- /* Replace a sequence of whitespace with a single space. */
- dest->appendc (' ');
- while (len > 1 && macro_is_whitespace (arg[1]))
- {
- ++arg;
- --len;
- }
- }
- else if (*arg == '\\' || *arg == '"')
- {
- dest->appendc ('\\');
- dest->appendc (*arg);
- }
- else
- dest->appendc (*arg);
- ++arg;
- --len;
- }
- dest->appendc ('"');
- dest->last_token = dest->len;
- }
- /* See macroexp.h. */
- gdb::unique_xmalloc_ptr<char>
- macro_stringify (const char *str)
- {
- int len = strlen (str);
- growable_macro_buffer buffer (len);
- stringify (&buffer, str, len);
- buffer.appendc ('\0');
- return buffer.release ();
- }
- /* 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) == 0)
- 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
- false, leave SRC unchanged, and don't set *ARGS_PTR to anything.
- If SRC doesn't contain a properly terminated argument list, then
- raise an error.
- For a variadic macro, NARGS holds the number of formal arguments to
- the macro. For a GNU-style variadic macro, this should be the
- number of named arguments. For a non-variadic macro, NARGS should
- be -1.
- Otherwise, return true and set *ARGS_PTR to a vector of macro
- buffers referring to the argument texts. The macro buffers share
- their text with SRC, and their last_token fields are initialized.
- 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 bool
- gather_arguments (const char *name, shared_macro_buffer *src, int nargs,
- std::vector<shared_macro_buffer> *args_ptr)
- {
- shared_macro_buffer tok;
- std::vector<shared_macro_buffer> 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. */
- {
- shared_macro_buffer temp (src->text, src->len);
- if (! get_token (&tok, &temp)
- || tok.len != 1
- || tok.text[0] != '(')
- return false;
- }
- /* Consume SRC's opening paren. */
- get_token (&tok, src);
- for (;;)
- {
- shared_macro_buffer *arg;
- int depth;
- /* Initialize the next argument. */
- args.emplace_back ();
- arg = &args.back ();
- set_token (arg, src->text, src->text);
- /* Gather the argument's tokens. */
- depth = 0;
- for (;;)
- {
- 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)
- {
- /* In the varargs case, the last argument may be
- missing. Add an empty argument in this case. */
- if (nargs != -1 && args.size () == nargs - 1)
- {
- args.emplace_back ();
- arg = &args.back ();
- set_token (arg, src->text, src->text);
- }
- *args_ptr = std::move (args);
- return true;
- }
- depth--;
- }
- /* If tok is a comma at top level, then that's the end of
- the current argument. However, if we are handling a
- variadic macro and we are computing the last argument, we
- want to include the comma and remaining tokens. */
- else if (tok.len == 1 && tok.text[0] == ',' && depth == 0
- && (nargs == -1 || args.size () < nargs))
- 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 (growable_macro_buffer *dest,
- shared_macro_buffer *src,
- struct macro_name_list *no_loop,
- const macro_scope &scope);
- /* A helper function for substitute_args.
-
- ARGV is a vector of all the arguments; ARGC is the number of
- arguments. IS_VARARGS is true if the macro being substituted is a
- varargs macro; in this case VA_ARG_NAME is the name of the
- "variable" argument. VA_ARG_NAME is ignored if IS_VARARGS is
- false.
- If the token TOK is the name of a parameter, return the parameter's
- index. If TOK is not an argument, return -1. */
- static int
- find_parameter (const shared_macro_buffer *tok,
- int is_varargs, const shared_macro_buffer *va_arg_name,
- int argc, const char * const *argv)
- {
- int i;
- if (! tok->is_identifier)
- return -1;
- for (i = 0; i < argc; ++i)
- if (tok->len == strlen (argv[i])
- && !memcmp (tok->text, argv[i], tok->len))
- return i;
- if (is_varargs && tok->len == va_arg_name->len
- && ! memcmp (tok->text, va_arg_name->text, tok->len))
- return argc - 1;
- return -1;
- }
-
- /* Helper function for substitute_args that gets the next token and
- updates the passed-in state variables. */
- static void
- get_next_token_for_substitution (shared_macro_buffer *replacement_list,
- shared_macro_buffer *token,
- const char **start,
- shared_macro_buffer *lookahead,
- const char **lookahead_start,
- int *lookahead_valid,
- bool *keep_going)
- {
- if (!*lookahead_valid)
- *keep_going = false;
- else
- {
- *keep_going = true;
- *token = *lookahead;
- *start = *lookahead_start;
- *lookahead_start = replacement_list->text;
- *lookahead_valid = get_token (lookahead, replacement_list);
- }
- }
- /* Given the macro definition DEF, being invoked with the actual
- arguments given by ARGV, substitute the arguments into the
- replacement list, and store the result in DEST.
- IS_VARARGS should be true if DEF is a varargs macro. In this case,
- VA_ARG_NAME should be the name of the "variable" argument -- either
- __VA_ARGS__ for c99-style varargs, or the final argument name, for
- GNU-style varargs. If IS_VARARGS is false, this parameter is
- ignored.
- 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 (growable_macro_buffer *dest,
- struct macro_definition *def,
- int is_varargs, const shared_macro_buffer *va_arg_name,
- const std::vector<shared_macro_buffer> &argv,
- struct macro_name_list *no_loop,
- const macro_scope &scope)
- {
- /* The token we are currently considering. */
- shared_macro_buffer tok;
- /* The replacement list's pointer from just before TOK was lexed. */
- const char *original_rl_start;
- /* We have a single lookahead token to handle token splicing. */
- shared_macro_buffer lookahead;
- /* The lookahead token might not be valid. */
- int lookahead_valid;
- /* The replacement list's pointer from just before LOOKAHEAD was
- lexed. */
- const char *lookahead_rl_start;
- /* A macro buffer for the macro's replacement list. */
- shared_macro_buffer replacement_list (def->replacement,
- strlen (def->replacement));
- gdb_assert (dest->len == 0);
- dest->last_token = 0;
- original_rl_start = replacement_list.text;
- if (! get_token (&tok, &replacement_list))
- return;
- lookahead_rl_start = replacement_list.text;
- lookahead_valid = get_token (&lookahead, &replacement_list);
- /* __VA_OPT__ state variable. The states are:
- 0 - nothing happening
- 1 - saw __VA_OPT__
- >= 2 in __VA_OPT__, the value encodes the parenthesis depth. */
- unsigned vaopt_state = 0;
- for (bool keep_going = true;
- keep_going;
- get_next_token_for_substitution (&replacement_list,
- &tok,
- &original_rl_start,
- &lookahead,
- &lookahead_rl_start,
- &lookahead_valid,
- &keep_going))
- {
- bool token_is_vaopt = (tok.len == 10
- && startswith (tok.text, "__VA_OPT__"));
- if (vaopt_state > 0)
- {
- if (token_is_vaopt)
- error (_("__VA_OPT__ cannot appear inside __VA_OPT__"));
- else if (tok.len == 1 && tok.text[0] == '(')
- {
- ++vaopt_state;
- /* We just entered __VA_OPT__, so don't emit this
- token. */
- continue;
- }
- else if (vaopt_state == 1)
- error (_("__VA_OPT__ must be followed by an open parenthesis"));
- else if (tok.len == 1 && tok.text[0] == ')')
- {
- --vaopt_state;
- if (vaopt_state == 1)
- {
- /* Done with __VA_OPT__. */
- vaopt_state = 0;
- /* Don't emit. */
- continue;
- }
- }
- /* If __VA_ARGS__ is empty, then drop the contents of
- __VA_OPT__. */
- if (argv.back ().len == 0)
- continue;
- }
- else if (token_is_vaopt)
- {
- if (!is_varargs)
- error (_("__VA_OPT__ is only valid in a variadic macro"));
- vaopt_state = 1;
- /* Don't emit this token. */
- continue;
- }
- /* Just for aesthetics. If we skipped some whitespace, copy
- that to DEST. */
- if (tok.text > original_rl_start)
- {
- dest->appendmem (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] == '#')
- {
- int arg;
- if (!lookahead_valid)
- error (_("Stringification operator requires an argument."));
- arg = find_parameter (&lookahead, is_varargs, va_arg_name,
- def->argc, def->argv);
- if (arg == -1)
- error (_("Argument to stringification operator must name "
- "a macro parameter."));
- stringify (dest, argv[arg].text, argv[arg].len);
- /* Read one token and let the loop iteration code handle the
- rest. */
- lookahead_rl_start = replacement_list.text;
- lookahead_valid = get_token (&lookahead, &replacement_list);
- }
- /* Is this token the splicing operator? */
- else if (tok.len == 2
- && tok.text[0] == '#'
- && tok.text[1] == '#')
- error (_("Stray splicing operator"));
- /* Is the next token the splicing operator? */
- else if (lookahead_valid
- && lookahead.len == 2
- && lookahead.text[0] == '#'
- && lookahead.text[1] == '#')
- {
- int finished = 0;
- int prev_was_comma = 0;
- /* Note that GCC warns if the result of splicing is not a
- token. In the debugger there doesn't seem to be much
- benefit from doing this. */
- /* Insert the first token. */
- if (tok.len == 1 && tok.text[0] == ',')
- prev_was_comma = 1;
- else
- {
- int arg = find_parameter (&tok, is_varargs, va_arg_name,
- def->argc, def->argv);
- if (arg != -1)
- dest->appendmem (argv[arg].text, argv[arg].len);
- else
- dest->appendmem (tok.text, tok.len);
- }
- /* Apply a possible sequence of ## operators. */
- for (;;)
- {
- if (! get_token (&tok, &replacement_list))
- error (_("Splicing operator at end of macro"));
- /* Handle a comma before a ##. If we are handling
- varargs, and the token on the right hand side is the
- varargs marker, and the final argument is empty or
- missing, then drop the comma. This is a GNU
- extension. There is one ambiguous case here,
- involving pedantic behavior with an empty argument,
- but we settle that in favor of GNU-style (GCC uses an
- option). If we aren't dealing with varargs, we
- simply insert the comma. */
- if (prev_was_comma)
- {
- if (! (is_varargs
- && tok.len == va_arg_name->len
- && !memcmp (tok.text, va_arg_name->text, tok.len)
- && argv.back ().len == 0))
- dest->appendmem (",", 1);
- prev_was_comma = 0;
- }
- /* Insert the token. If it is a parameter, insert the
- argument. If it is a comma, treat it specially. */
- if (tok.len == 1 && tok.text[0] == ',')
- prev_was_comma = 1;
- else
- {
- int arg = find_parameter (&tok, is_varargs, va_arg_name,
- def->argc, def->argv);
- if (arg != -1)
- dest->appendmem (argv[arg].text, argv[arg].len);
- else
- dest->appendmem (tok.text, tok.len);
- }
- /* Now read another token. If it is another splice, we
- loop. */
- original_rl_start = replacement_list.text;
- if (! get_token (&tok, &replacement_list))
- {
- finished = 1;
- break;
- }
- if (! (tok.len == 2
- && tok.text[0] == '#'
- && tok.text[1] == '#'))
- break;
- }
- if (prev_was_comma)
- {
- /* We saw a comma. Insert it now. */
- dest->appendmem (",", 1);
- }
- dest->last_token = dest->len;
- if (finished)
- lookahead_valid = 0;
- else
- {
- /* Set up for the loop iterator. */
- lookahead = tok;
- lookahead_rl_start = original_rl_start;
- lookahead_valid = 1;
- }
- }
- else
- {
- /* Is this token an identifier? */
- int substituted = 0;
- int arg = find_parameter (&tok, is_varargs, va_arg_name,
- def->argc, def->argv);
- if (arg != -1)
- {
- /* 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. */
- shared_macro_buffer arg_src (argv[arg].text, argv[arg].len);
- scan (dest, &arg_src, no_loop, scope);
- substituted = 1;
- }
- /* If it wasn't a parameter, then just copy it across. */
- if (! substituted)
- append_tokens_without_splicing (dest, &tok);
- }
- }
- if (vaopt_state > 0)
- error (_("Unterminated __VA_OPT__"));
- }
- /* 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,
- growable_macro_buffer *dest,
- shared_macro_buffer *src,
- struct macro_name_list *no_loop,
- const macro_scope &scope)
- {
- 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)
- {
- shared_macro_buffer replacement_list (def->replacement,
- strlen (def->replacement));
- scan (dest, &replacement_list, &new_no_loop, scope);
- return 1;
- }
- else if (def->kind == macro_function_like)
- {
- shared_macro_buffer va_arg_name;
- int is_varargs = 0;
- if (def->argc >= 1)
- {
- if (strcmp (def->argv[def->argc - 1], "...") == 0)
- {
- /* In C99-style varargs, substitution is done using
- __VA_ARGS__. */
- va_arg_name.set_shared ("__VA_ARGS__", strlen ("__VA_ARGS__"));
- is_varargs = 1;
- }
- else
- {
- int len = strlen (def->argv[def->argc - 1]);
- if (len > 3
- && strcmp (def->argv[def->argc - 1] + len - 3, "...") == 0)
- {
- /* In GNU-style varargs, the name of the
- substitution parameter is the name of the formal
- argument without the "...". */
- va_arg_name.set_shared (def->argv[def->argc - 1], len - 3);
- is_varargs = 1;
- }
- }
- }
- std::vector<shared_macro_buffer> argv;
- /* If we couldn't find any argument list, then we don't expand
- this macro. */
- if (!gather_arguments (id, src, is_varargs ? def->argc : -1,
- &argv))
- return 0;
- /* Check that we're passing an acceptable number of arguments for
- this macro. */
- if (argv.size () != def->argc)
- {
- if (is_varargs && argv.size () >= def->argc - 1)
- {
- /* Ok. */
- }
- /* Remember that a sequence of tokens like "foo()" is a
- valid invocation of a macro expecting either zero or one
- arguments. */
- else if (! (argv.size () == 1
- && argv[0].len == 0
- && def->argc == 0))
- error (_("Wrong number of arguments to macro `%s' "
- "(expected %d, got %d)."),
- id, def->argc, int (argv.size ()));
- }
- /* 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. */
- growable_macro_buffer substituted (0);
- substitute_args (&substituted, def, is_varargs, &va_arg_name,
- argv, no_loop, scope);
- /* 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. */
- shared_macro_buffer substituted_src (substituted.text, substituted.len);
- scan (dest, &substituted_src, &new_no_loop, scope);
- 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 invocation not forbidden in NO_LOOP, append its
- expansion to DEST and return non-zero. Otherwise, return zero, and
- leave DEST unchanged.
- SRC_FIRST must be a string built by get_token. */
- static int
- maybe_expand (growable_macro_buffer *dest,
- shared_macro_buffer *src_first,
- shared_macro_buffer *src_rest,
- struct macro_name_list *no_loop,
- const macro_scope &scope)
- {
- /* 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. */
- std::string id (src_first->text, src_first->len);
- /* If we're currently re-scanning the result of expanding
- this macro, don't expand it again. */
- if (! currently_rescanning (no_loop, id.c_str ()))
- {
- /* Does this identifier have a macro definition in scope? */
- macro_definition *def = standard_macro_lookup (id.c_str (), scope);
- if (def && expand (id.c_str (), def, dest, src_rest, no_loop, scope))
- return 1;
- }
- }
- 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. */
- static void
- scan (growable_macro_buffer *dest,
- shared_macro_buffer *src,
- struct macro_name_list *no_loop,
- const macro_scope &scope)
- {
- for (;;)
- {
- shared_macro_buffer tok;
- const 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)
- {
- dest->appendmem (original_src_start, tok.text - original_src_start);
- dest->last_token = dest->len;
- }
- if (! maybe_expand (dest, &tok, src, no_loop, scope))
- /* 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)
- {
- dest->appendmem (src->text, src->len);
- dest->last_token = dest->len;
- }
- }
- gdb::unique_xmalloc_ptr<char>
- macro_expand (const char *source, const macro_scope &scope)
- {
- shared_macro_buffer src (source, strlen (source));
- growable_macro_buffer dest (0);
- dest.last_token = 0;
- scan (&dest, &src, 0, scope);
- dest.appendc ('\0');
- return dest.release ();
- }
- gdb::unique_xmalloc_ptr<char>
- macro_expand_once (const char *source, const macro_scope &scope)
- {
- error (_("Expand-once not implemented yet."));
- }
- gdb::unique_xmalloc_ptr<char>
- macro_expand_next (const char **lexptr, const macro_scope &scope)
- {
- shared_macro_buffer tok;
- /* Set up SRC to refer to the input text, pointed to by *lexptr. */
- shared_macro_buffer src (*lexptr, strlen (*lexptr));
- /* Set up DEST to receive the expansion, if there is one. */
- growable_macro_buffer dest (0);
- dest.last_token = 0;
- /* Get the text's first preprocessing token. */
- if (! get_token (&tok, &src))
- return nullptr;
- /* If it's a macro invocation, expand it. */
- if (maybe_expand (&dest, &tok, &src, 0, scope))
- {
- /* 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. */
- dest.appendc ('\0');
- *lexptr = src.text;
- return dest.release ();
- }
- else
- {
- /* It wasn't a macro invocation. */
- return nullptr;
- }
- }
|