libcpp: Handle extended characters in user-defined literal suffix [PR103902]

The PR complains that we do not handle UTF-8 in the suffix for a user-defined
literal, such as:

bool operator ""_π (unsigned long long);

In fact we don't handle any extended identifier characters there, whether
UTF-8, UCNs, or the $ sign. We do handle it fine if the optional space after
the "" tokens is included, since then the identifier is lexed in the
"normal" way as its own token. But when it is lexed as part of the string
token, this is handled in lex_string() with a one-off loop that is not aware
of extended characters.

This patch fixes it by adding a new function scan_cur_identifier() that can
be used to lex an identifier while in the middle of lexing another token.

BTW, the other place that has been mis-lexing identifiers is
lex_identifier_intern(), which is used to implement #pragma push_macro
and #pragma pop_macro. This does not support extended characters either.
I will add that in a subsequent patch, because it can't directly reuse the
new function, but rather needs to lex from a string instead of a cpp_buffer.

With scan_cur_identifier(), we do also correctly warn about bidi and
normalization issues in the extended identifiers comprising the suffix.

libcpp/ChangeLog:

	PR preprocessor/103902
	* lex.cc (identifier_diagnostics_on_lex): New function refactoring
	some common code.
	(lex_identifier_intern): Use the new function.
	(lex_identifier): Don't run identifier diagnostics here, rather let
	the call site do it when needed.
	(_cpp_lex_direct): Adjust the call sites of lex_identifier ()
	acccordingly.
	(struct scan_id_result): New struct.
	(scan_cur_identifier): New function.
	(create_literal2): New function.
	(lit_accum::create_literal2): New function.
	(is_macro): Folded into new function...
	(maybe_ignore_udl_macro_suffix): ...here.
	(is_macro_not_literal_suffix): Folded likewise.
	(lex_raw_string): Handle UTF-8 in UDL suffix via
	scan_cur_identifier ().
	(lex_string): Likewise.

gcc/testsuite/ChangeLog:

	PR preprocessor/103902
	* g++.dg/cpp0x/udlit-extended-id-1.C: New test.
	* g++.dg/cpp0x/udlit-extended-id-2.C: New test.
	* g++.dg/cpp0x/udlit-extended-id-3.C: New test.
	* g++.dg/cpp0x/udlit-extended-id-4.C: New test.
This commit is contained in:
Lewis Hyatt 2023-07-18 17:16:08 -04:00
parent 9a19fa8b61
commit 1d3e4f4e2d
5 changed files with 321 additions and 167 deletions

View file

@ -0,0 +1,71 @@
// { dg-do run { target c++11 } }
// { dg-additional-options "-Wno-error=normalized" }
#include <cstring>
using namespace std;
constexpr unsigned long long operator "" (unsigned long long x)
{
return 3 * x;
}
/* Historically we didn't parse properly as part of the "" token, so check that
as well. */
constexpr unsigned long long operator ""_Π2 (unsigned long long x)
{
return 4 * x;
}
char x1[1];
char x2[2_Π2];
static_assert (sizeof x1 == 3, "test1");
static_assert (sizeof x2 == 8, "test2");
const char * operator "" _1σ (const char *s, unsigned long)
{
return s + 1;
}
const char * operator ""_Σ2 (const char *s, unsigned long)
{
return s + 2;
}
const char * operator "" _\U000000e61 (const char *s, unsigned long)
{
return "ae";
}
const char* operator ""_\u01532 (const char *s, unsigned long)
{
return "oe";
}
bool operator "" _\u0BC7\u0BBE (unsigned long long); // { dg-warning "not in NFC" }
bool operator ""_\u0B47\U00000B3E (unsigned long long); // { dg-warning "not in NFC" }
#define xτy
const char * str = ""xτy; // { dg-warning "invalid suffix on literal" }
int main()
{
if (3 != 9)
__builtin_abort ();
if (4_Π2 != 16)
__builtin_abort ();
if (strcmp ("abc"_1σ, "bc"))
__builtin_abort ();
if (strcmp ("abcd"_Σ2, "cd"))
__builtin_abort ();
if (strcmp (R"(abcdef)"_1σ, "bcdef"))
__builtin_abort ();
if (strcmp (R"(abc
def)"_1σ, "bc\ndef"))
__builtin_abort ();
if (strcmp (R"(abcdef)"_Σ2, "cdef"))
__builtin_abort ();
if (strcmp ("xyz"_æ1, "ae"))
__builtin_abort ();
if (strcmp ("xyz"_œ2, "oe"))
__builtin_abort ();
}

View file

@ -0,0 +1,6 @@
// { dg-do compile { target c++11 } }
// { dg-additional-options "-Wbidi-chars=any,ucn" }
bool operator ""_d\u202ae\u202cf (unsigned long long); // { dg-line line1 }
// { dg-error "universal character \\\\u202a is not valid in an identifier" "test1" { target *-*-* } line1 }
// { dg-error "universal character \\\\u202c is not valid in an identifier" "test2" { target *-*-* } line1 }
// { dg-warning "found problematic Unicode character" "test3" { target *-*-* } line1 }

View file

@ -0,0 +1,15 @@
// { dg-do compile { target c++11 } }
// Check that we do not look for poisoned identifier when it is a suffix.
int ;
#pragma GCC poison _ħ
const char * operator "" (const char *, unsigned long); // { dg-bogus "poisoned" }
bool operator "" (unsigned long long x); // { dg-bogus "poisoned" }
bool b = 1; // { dg-bogus "poisoned" }
const char *x = "hbar"; // { dg-bogus "poisoned" }
/* Ideally, we should not warn here either, but this is not implemented yet. This
syntax has been deprecated for C++23. */
#pragma GCC poison _ħ2
const char * operator "" _ħ2 (const char *, unsigned long); // { dg-bogus "poisoned" "" { xfail *-*-*} }
const char *x2 = "hbar2"_ħ2; // { dg-bogus "poisoned" }

View file

@ -0,0 +1,14 @@
// { dg-options "-std=c++98 -Wc++11-compat" }
#define END ;
#define εND ;
#define EηD ;
#define EN\u0394 ;
const char *s1 = "s1"END // { dg-warning "requires a space between string literal and macro" }
const char *s2 = "s2"εND // { dg-warning "requires a space between string literal and macro" }
const char *s3 = "s3"EηD // { dg-warning "requires a space between string literal and macro" }
const char *s4 = "s4"ENΔ // { dg-warning "requires a space between string literal and macro" }
/* Make sure we did not skip the token also in the case that it wasn't found to
be a macro; compilation should fail here. */
const char *s5 = "s5"NØT_A_MACRO; // { dg-error "expected ',' or ';' before" }

View file

@ -2057,8 +2057,11 @@ warn_about_normalization (cpp_reader *pfile,
}
}
/* Returns TRUE if the sequence starting at buffer->cur is valid in
an identifier. FIRST is TRUE if this starts an identifier. */
/* Returns TRUE if the byte sequence starting at buffer->cur is a valid
extended character in an identifier. If FIRST is TRUE, then the character
must be valid at the beginning of an identifier as well. If the return
value is TRUE, then pfile->buffer->cur has been moved to point to the next
byte after the extended character. */
static bool
forms_identifier_p (cpp_reader *pfile, int first,
@ -2154,6 +2157,47 @@ maybe_va_opt_error (cpp_reader *pfile)
}
}
/* Helper function to perform diagnostics that are needed (rarely)
when an identifier is lexed. */
static void
identifier_diagnostics_on_lex (cpp_reader *pfile, cpp_hashnode *node)
{
if (__builtin_expect (!(node->flags & NODE_DIAGNOSTIC)
|| pfile->state.skipping, 1))
return;
/* It is allowed to poison the same identifier twice. */
if ((node->flags & NODE_POISONED) && !pfile->state.poisoned_ok)
cpp_error (pfile, CPP_DL_ERROR, "attempt to use poisoned \"%s\"",
NODE_NAME (node));
/* Constraint 6.10.3.5: __VA_ARGS__ should only appear in the
replacement list of a variadic macro. */
if (node == pfile->spec_nodes.n__VA_ARGS__
&& !pfile->state.va_args_ok)
{
if (CPP_OPTION (pfile, cplusplus))
cpp_error (pfile, CPP_DL_PEDWARN,
"__VA_ARGS__ can only appear in the expansion"
" of a C++11 variadic macro");
else
cpp_error (pfile, CPP_DL_PEDWARN,
"__VA_ARGS__ can only appear in the expansion"
" of a C99 variadic macro");
}
/* __VA_OPT__ should only appear in the replacement list of a
variadic macro. */
if (node == pfile->spec_nodes.n__VA_OPT__)
maybe_va_opt_error (pfile);
/* For -Wc++-compat, warn about use of C++ named operators. */
if (node->flags & NODE_WARN_OPERATOR)
cpp_warning (pfile, CPP_W_CXX_OPERATOR_NAMES,
"identifier \"%s\" is a special operator name in C++",
NODE_NAME (node));
}
/* Helper function to get the cpp_hashnode of the identifier BASE. */
static cpp_hashnode *
lex_identifier_intern (cpp_reader *pfile, const uchar *base)
@ -2173,41 +2217,7 @@ lex_identifier_intern (cpp_reader *pfile, const uchar *base)
hash = HT_HASHFINISH (hash, len);
result = CPP_HASHNODE (ht_lookup_with_hash (pfile->hash_table,
base, len, hash, HT_ALLOC));
/* Rarely, identifiers require diagnostics when lexed. */
if (__builtin_expect ((result->flags & NODE_DIAGNOSTIC)
&& !pfile->state.skipping, 0))
{
/* It is allowed to poison the same identifier twice. */
if ((result->flags & NODE_POISONED) && !pfile->state.poisoned_ok)
cpp_error (pfile, CPP_DL_ERROR, "attempt to use poisoned \"%s\"",
NODE_NAME (result));
/* Constraint 6.10.3.5: __VA_ARGS__ should only appear in the
replacement list of a variadic macro. */
if (result == pfile->spec_nodes.n__VA_ARGS__
&& !pfile->state.va_args_ok)
{
if (CPP_OPTION (pfile, cplusplus))
cpp_error (pfile, CPP_DL_PEDWARN,
"__VA_ARGS__ can only appear in the expansion"
" of a C++11 variadic macro");
else
cpp_error (pfile, CPP_DL_PEDWARN,
"__VA_ARGS__ can only appear in the expansion"
" of a C99 variadic macro");
}
if (result == pfile->spec_nodes.n__VA_OPT__)
maybe_va_opt_error (pfile);
/* For -Wc++-compat, warn about use of C++ named operators. */
if (result->flags & NODE_WARN_OPERATOR)
cpp_warning (pfile, CPP_W_CXX_OPERATOR_NAMES,
"identifier \"%s\" is a special operator name in C++",
NODE_NAME (result));
}
identifier_diagnostics_on_lex (pfile, result);
return result;
}
@ -2221,7 +2231,9 @@ _cpp_lex_identifier (cpp_reader *pfile, const char *name)
return result;
}
/* Lex an identifier starting at BUFFER->CUR - 1. */
/* Lex an identifier starting at BASE. BUFFER->CUR is expected to point
one past the first character at BASE, which may be a (possibly multi-byte)
character if STARTS_UCN is true. */
static cpp_hashnode *
lex_identifier (cpp_reader *pfile, const uchar *base, bool starts_ucn,
struct normalize_state *nst, cpp_hashnode **spelling)
@ -2270,42 +2282,51 @@ lex_identifier (cpp_reader *pfile, const uchar *base, bool starts_ucn,
*spelling = result;
}
/* Rarely, identifiers require diagnostics when lexed. */
if (__builtin_expect ((result->flags & NODE_DIAGNOSTIC)
&& !pfile->state.skipping, 0))
return result;
}
/* Struct to hold the return value of the scan_cur_identifier () helper
function below. */
struct scan_id_result
{
cpp_hashnode *node;
normalize_state nst;
scan_id_result ()
: node (nullptr)
{
nst = INITIAL_NORMALIZE_STATE;
}
explicit operator bool () const { return node; }
};
/* Helper function to scan an entire identifier beginning at
pfile->buffer->cur, and possibly containing extended characters (UCNs
and/or UTF-8). Returns the cpp_hashnode for the identifier on success, or
else nullptr, as well as a normalize_state so that normalization warnings
may be issued once the token lexing is complete. */
static scan_id_result
scan_cur_identifier (cpp_reader *pfile)
{
const auto buffer = pfile->buffer;
const auto begin = buffer->cur;
scan_id_result result;
if (ISIDST (*buffer->cur))
{
/* It is allowed to poison the same identifier twice. */
if ((result->flags & NODE_POISONED) && !pfile->state.poisoned_ok)
cpp_error (pfile, CPP_DL_ERROR, "attempt to use poisoned \"%s\"",
NODE_NAME (result));
/* Constraint 6.10.3.5: __VA_ARGS__ should only appear in the
replacement list of a variadic macro. */
if (result == pfile->spec_nodes.n__VA_ARGS__
&& !pfile->state.va_args_ok)
{
if (CPP_OPTION (pfile, cplusplus))
cpp_error (pfile, CPP_DL_PEDWARN,
"__VA_ARGS__ can only appear in the expansion"
" of a C++11 variadic macro");
else
cpp_error (pfile, CPP_DL_PEDWARN,
"__VA_ARGS__ can only appear in the expansion"
" of a C99 variadic macro");
}
/* __VA_OPT__ should only appear in the replacement list of a
variadic macro. */
if (result == pfile->spec_nodes.n__VA_OPT__)
maybe_va_opt_error (pfile);
/* For -Wc++-compat, warn about use of C++ named operators. */
if (result->flags & NODE_WARN_OPERATOR)
cpp_warning (pfile, CPP_W_CXX_OPERATOR_NAMES,
"identifier \"%s\" is a special operator name in C++",
NODE_NAME (result));
++buffer->cur;
cpp_hashnode *ignore;
result.node = lex_identifier (pfile, begin, false, &result.nst, &ignore);
}
else if (forms_identifier_p (pfile, true, &result.nst))
{
/* buffer->cur has been moved already by the call
to forms_identifier_p. */
cpp_hashnode *ignore;
result.node = lex_identifier (pfile, begin, true, &result.nst, &ignore);
}
return result;
}
@ -2365,6 +2386,24 @@ create_literal (cpp_reader *pfile, cpp_token *token, const uchar *base,
token->val.str.text = cpp_alloc_token_string (pfile, base, len);
}
/* Like create_literal(), but construct it from two separate strings
which are concatenated. LEN2 may be 0 if no second string is
required. */
static void
create_literal2 (cpp_reader *pfile, cpp_token *token, const uchar *base1,
unsigned int len1, const uchar *base2, unsigned int len2,
enum cpp_ttype type)
{
token->type = type;
token->val.str.len = len1 + len2;
uchar *const dest = _cpp_unaligned_alloc (pfile, len1 + len2 + 1);
memcpy (dest, base1, len1);
if (len2)
memcpy (dest+len1, base2, len2);
dest[len1 + len2] = 0;
token->val.str.text = dest;
}
const uchar *
cpp_alloc_token_string (cpp_reader *pfile,
const unsigned char *ptr, unsigned len)
@ -2403,6 +2442,11 @@ struct lit_accum {
rpos = NULL;
return c;
}
void create_literal2 (cpp_reader *pfile, cpp_token *token,
const uchar *base1, unsigned int len1,
const uchar *base2, unsigned int len2,
enum cpp_ttype type);
};
/* Subroutine of lex_raw_string: Append LEN chars from BASE to the buffer
@ -2445,45 +2489,59 @@ lit_accum::read_begin (cpp_reader *pfile)
rpos = BUFF_FRONT (last);
}
/* Returns true if a macro has been defined.
This might not work if compile with -save-temps,
or preprocess separately from compilation. */
/* Helper function to check if a string format macro, say from inttypes.h, is
placed touching a string literal, in which case it could be parsed as a C++11
user-defined string literal thus breaking the program. Return TRUE if the
UDL should be ignored for now and preserved for potential macro
expansion. */
static bool
is_macro(cpp_reader *pfile, const uchar *base)
{
const uchar *cur = base;
if (! ISIDST (*cur))
return false;
unsigned int hash = HT_HASHSTEP (0, *cur);
++cur;
while (ISIDNUM (*cur))
{
hash = HT_HASHSTEP (hash, *cur);
++cur;
}
hash = HT_HASHFINISH (hash, cur - base);
cpp_hashnode *result = CPP_HASHNODE (ht_lookup_with_hash (pfile->hash_table,
base, cur - base, hash, HT_NO_INSERT));
return result && cpp_macro_p (result);
}
/* Returns true if a literal suffix does not have the expected form
and is defined as a macro. */
static bool
is_macro_not_literal_suffix(cpp_reader *pfile, const uchar *base)
maybe_ignore_udl_macro_suffix (cpp_reader *pfile, location_t src_loc,
const uchar *suffix_begin, cpp_hashnode *node)
{
/* User-defined literals outside of namespace std must start with a single
underscore, so assume anything of that form really is a UDL suffix.
We don't need to worry about UDLs defined inside namespace std because
their names are reserved, so cannot be used as macro names in valid
programs. */
if (base[0] == '_' && base[1] != '_')
if ((suffix_begin[0] == '_' && suffix_begin[1] != '_')
|| !cpp_macro_p (node))
return false;
return is_macro (pfile, base);
/* Maybe raise a warning here; caller should arrange not to consume
the tokens. */
if (CPP_OPTION (pfile, warn_literal_suffix) && !pfile->state.skipping)
cpp_warning_with_line (pfile, CPP_W_LITERAL_SUFFIX, src_loc, 0,
"invalid suffix on literal; C++11 requires a space "
"between literal and string macro");
return true;
}
/* Like create_literal2(), but also prepend all the accumulated data from
the lit_accum struct. */
void
lit_accum::create_literal2 (cpp_reader *pfile, cpp_token *token,
const uchar *base1, unsigned int len1,
const uchar *base2, unsigned int len2,
enum cpp_ttype type)
{
const unsigned int tot_len = accum + len1 + len2;
uchar *dest = _cpp_unaligned_alloc (pfile, tot_len + 1);
token->type = type;
token->val.str.len = tot_len;
token->val.str.text = dest;
for (_cpp_buff *buf = first; buf; buf = buf->next)
{
size_t len = BUFF_FRONT (buf) - buf->base;
memcpy (dest, buf->base, len);
dest += len;
}
memcpy (dest, base1, len1);
dest += len1;
if (len2)
memcpy (dest, base2, len2);
dest += len2;
*dest = '\0';
}
/* Lexes a raw string. The stored string contains the spelling,
@ -2758,26 +2816,25 @@ lex_raw_string (cpp_reader *pfile, cpp_token *token, const uchar *base)
if (CPP_OPTION (pfile, user_literals))
{
/* If a string format macro, say from inttypes.h, is placed touching
a string literal it could be parsed as a C++11 user-defined string
literal thus breaking the program. */
if (is_macro_not_literal_suffix (pfile, pos))
{
/* Raise a warning, but do not consume subsequent tokens. */
if (CPP_OPTION (pfile, warn_literal_suffix) && !pfile->state.skipping)
cpp_warning_with_line (pfile, CPP_W_LITERAL_SUFFIX,
token->src_loc, 0,
"invalid suffix on literal; C++11 requires "
"a space between literal and string macro");
}
/* Grab user defined literal suffix. */
else if (ISIDST (*pos))
{
type = cpp_userdef_string_add_type (type);
++pos;
const uchar *const suffix_begin = pos;
pfile->buffer->cur = pos;
while (ISIDNUM (*pos))
++pos;
if (const auto sr = scan_cur_identifier (pfile))
{
if (maybe_ignore_udl_macro_suffix (pfile, token->src_loc,
suffix_begin, sr.node))
pfile->buffer->cur = suffix_begin;
else
{
type = cpp_userdef_string_add_type (type);
accum.create_literal2 (pfile, token, base, suffix_begin - base,
NODE_NAME (sr.node), NODE_LEN (sr.node),
type);
if (accum.first)
_cpp_release_buff (pfile, accum.first);
warn_about_normalization (pfile, token, &sr.nst, true);
return;
}
}
}
@ -2787,21 +2844,8 @@ lex_raw_string (cpp_reader *pfile, cpp_token *token, const uchar *base)
create_literal (pfile, token, base, pos - base, type);
else
{
size_t extra_len = pos - base;
uchar *dest = _cpp_unaligned_alloc (pfile, accum.accum + extra_len + 1);
token->type = type;
token->val.str.len = accum.accum + extra_len;
token->val.str.text = dest;
for (_cpp_buff *buf = accum.first; buf; buf = buf->next)
{
size_t len = BUFF_FRONT (buf) - buf->base;
memcpy (dest, buf->base, len);
dest += len;
}
accum.create_literal2 (pfile, token, base, pos - base, nullptr, 0, type);
_cpp_release_buff (pfile, accum.first);
memcpy (dest, base, extra_len);
dest[extra_len] = '\0';
}
}
@ -2908,39 +2952,40 @@ lex_string (cpp_reader *pfile, cpp_token *token, const uchar *base)
cpp_error (pfile, CPP_DL_PEDWARN, "missing terminating %c character",
(int) terminator);
pfile->buffer->cur = cur;
const uchar *const suffix_begin = cur;
if (CPP_OPTION (pfile, user_literals))
{
/* If a string format macro, say from inttypes.h, is placed touching
a string literal it could be parsed as a C++11 user-defined string
literal thus breaking the program. */
if (is_macro_not_literal_suffix (pfile, cur))
if (const auto sr = scan_cur_identifier (pfile))
{
/* Raise a warning, but do not consume subsequent tokens. */
if (CPP_OPTION (pfile, warn_literal_suffix) && !pfile->state.skipping)
cpp_warning_with_line (pfile, CPP_W_LITERAL_SUFFIX,
token->src_loc, 0,
"invalid suffix on literal; C++11 requires "
"a space between literal and string macro");
}
/* Grab user defined literal suffix. */
else if (ISIDST (*cur))
{
type = cpp_userdef_char_add_type (type);
type = cpp_userdef_string_add_type (type);
++cur;
while (ISIDNUM (*cur))
++cur;
if (maybe_ignore_udl_macro_suffix (pfile, token->src_loc,
suffix_begin, sr.node))
pfile->buffer->cur = suffix_begin;
else
{
/* Grab user defined literal suffix. */
type = cpp_userdef_char_add_type (type);
type = cpp_userdef_string_add_type (type);
create_literal2 (pfile, token, base, suffix_begin - base,
NODE_NAME (sr.node), NODE_LEN (sr.node), type);
warn_about_normalization (pfile, token, &sr.nst, true);
return;
}
}
}
else if (CPP_OPTION (pfile, cpp_warn_cxx11_compat)
&& is_macro (pfile, cur)
&& !pfile->state.skipping)
cpp_warning_with_line (pfile, CPP_W_CXX11_COMPAT,
token->src_loc, 0, "C++11 requires a space "
"between string literal and macro");
{
const auto sr = scan_cur_identifier (pfile);
/* Maybe raise a warning, but do not consume the tokens. */
pfile->buffer->cur = suffix_begin;
if (sr && cpp_macro_p (sr.node))
cpp_warning_with_line (pfile, CPP_W_CXX11_COMPAT,
token->src_loc, 0, "C++11 requires a space "
"between string literal and macro");
}
pfile->buffer->cur = cur;
create_literal (pfile, token, base, cur - base, type);
}
@ -3915,9 +3960,10 @@ _cpp_lex_direct (cpp_reader *pfile)
result->type = CPP_NAME;
{
struct normalize_state nst = INITIAL_NORMALIZE_STATE;
result->val.node.node = lex_identifier (pfile, buffer->cur - 1, false,
&nst,
&result->val.node.spelling);
const auto node = lex_identifier (pfile, buffer->cur - 1, false, &nst,
&result->val.node.spelling);
result->val.node.node = node;
identifier_diagnostics_on_lex (pfile, node);
warn_about_normalization (pfile, result, &nst, true);
}
@ -4220,8 +4266,10 @@ _cpp_lex_direct (cpp_reader *pfile)
if (forms_identifier_p (pfile, true, &nst))
{
result->type = CPP_NAME;
result->val.node.node = lex_identifier (pfile, base, true, &nst,
&result->val.node.spelling);
const auto node = lex_identifier (pfile, base, true, &nst,
&result->val.node.spelling);
result->val.node.node = node;
identifier_diagnostics_on_lex (pfile, node);
warn_about_normalization (pfile, result, &nst, true);
break;
}
@ -4353,7 +4401,7 @@ cpp_digraph2name (enum cpp_ttype type)
}
/* Write the spelling of an identifier IDENT, using UCNs, to BUFFER.
The buffer must already contain the enough space to hold the
The buffer must already contain enough space to hold the
token's spelling. Returns a pointer to the character after the
last character written. */
unsigned char *
@ -4375,7 +4423,7 @@ _cpp_spell_ident_ucns (unsigned char *buffer, cpp_hashnode *ident)
}
/* Write the spelling of a token TOKEN to BUFFER. The buffer must
already contain the enough space to hold the token's spelling.
already contain enough space to hold the token's spelling.
Returns a pointer to the character after the last character written.
FORSTRING is true if this is to be the spelling after translation
phase 1 (with the original spelling of extended identifiers), false