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cpplex.c (parse_identifier): Fast-path optimize.

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* cpplex.c (parse_identifier): Fast-path optimize.  Avoid
	copying identifier when we're just going to throw it away.
	(parse_identifier_slow): New routine to handle abnormal cases.
	(_cpp_lex_token): Update call site.

	* hashtable.c (ht_lookup): Don't assume that the string we've
	been given is NUL-terminated.
	* system.h: #define __builtin_expect(a, b) to (a) if not
	GCC >=3.0.

From-SVN: r45529
This commit is contained in:
Zack Weinberg 2001-09-10 22:34:03 +00:00
parent b210ec460e
commit 2c3fcba6dc
4 changed files with 113 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
gcc/ChangeLog
View File

@ -1,3 +1,15 @@
2001-09-10 Zack Weinberg <zackw@panix.com>
* cpplex.c (parse_identifier): Fast-path optimize. Avoid
copying identifier when we're just going to throw it away.
(parse_identifier_slow): New routine to handle abnormal cases.
(_cpp_lex_token): Update call site.
* hashtable.c (ht_lookup): Don't assume that the string we've
been given is NUL-terminated.
* system.h: #define __builtin_expect(a, b) to (a) if not
GCC >=3.0.
2001-09-10 Michael Meissner <meissner@redhat.com>
* config.gcc (sparc64-*-solaris2): Add alias to be compatible with
@ -16,7 +28,7 @@ Mon Sep 10 16:26:44 2001 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
* dwarf2out.c (incomplete_types, decl_scope_table): Make them
into varray's and register them as roots with the garbage
collector so they are not collected too soon.
collector so they are not collected too soon.
Mon Sep 10 14:21:26 CEST 2001 Jan Hubicka <jh@suse.cz>
@ -31,7 +43,7 @@ Mon Sep 10 14:21:26 CEST 2001 Jan Hubicka <jh@suse.cz>
(basic_block_for_insn, label_value_list): Move from flow.c; make global.
(n_basic_blocks, n_edges, basic_block_info, entry_exit_blocks,
init_flow, clear_edges, can_delete_note_p, can_delete_label_p,
flow_delete_insn, flow_delete_insn_chain, create_basic_block,
flow_delete_insn, flow_delete_insn_chain, create_basic_block,
expunge_block, flow_delete_block, compute_bb_for_insn,
update_bb_for_insn, set_block_for_insn, set_block_for_new_insns,
make_edge, remove_edge, redirect_edge_succ, redirect_edge_succ_nodup,
@ -40,7 +52,7 @@ Mon Sep 10 14:21:26 CEST 2001 Jan Hubicka <jh@suse.cz>
redirect_edge_and_branch, redirect_edge_and_branch_force,
tidy_fallthru_edge, tidy_fallthru_edges, back_edge_of_syntactic_loop_p,
split_edge, insert_insn_on_edge, commit_one_edge_insertion,
commit_edge_insertions, dump_flow_info, debug_flow_info,
commit_edge_insertions, dump_flow_info, debug_flow_info,
dump_edge_info, dump_bb, debug_bb, debug_bb_n, print_rtl_with_bb,
verify_flow_info, purge_dead_edges, purge_all_dead_edges):
Move here from flow.c

132
gcc/cpplex.c
View File

@ -88,7 +88,9 @@ static int skip_block_comment PARAMS ((cpp_reader *));
static int skip_line_comment PARAMS ((cpp_reader *));
static void adjust_column PARAMS ((cpp_reader *));
static void skip_whitespace PARAMS ((cpp_reader *, cppchar_t));
static cpp_hashnode *parse_identifier PARAMS ((cpp_reader *, cppchar_t));
static cpp_hashnode *parse_identifier PARAMS ((cpp_reader *));
static cpp_hashnode *parse_identifier_slow PARAMS ((cpp_reader *,
const U_CHAR *));
static void parse_number PARAMS ((cpp_reader *, cpp_string *, cppchar_t, int));
static int unescaped_terminator_p PARAMS ((cpp_reader *, const U_CHAR *));
static void parse_string PARAMS ((cpp_reader *, cpp_token *, cppchar_t));
@ -470,40 +472,101 @@ name_p (pfile, string)
return 1;
}
/* Parse an identifier, skipping embedded backslash-newlines.
Calculate the hash value of the token while parsing, for improved
performance. The hashing algorithm *must* match cpp_lookup(). */
/* Parse an identifier, skipping embedded backslash-newlines. This is
a critical inner loop. The common case is an identifier which has
not been split by backslash-newline, does not contain a dollar
sign, and has already been scanned (roughly 10:1 ratio of
seen:unseen identifiers in normal code; the distribution is
Poisson-like). Second most common case is a new identifier, not
split and no dollar sign. The other possibilities are rare and
have been relegated to parse_identifier_slow. */
static cpp_hashnode *
parse_identifier (pfile, c)
parse_identifier (pfile)
cpp_reader *pfile;
cppchar_t c;
{
cpp_hashnode *result;
cpp_buffer *buffer = pfile->buffer;
unsigned int saw_dollar = 0, len;
struct obstack *stack = &pfile->hash_table->stack;
const U_CHAR *cur, *rlimit;
/* Fast-path loop. Skim over a normal identifier.
N.B. ISIDNUM does not include $. */
cur = pfile->buffer->cur - 1;
rlimit = pfile->buffer->rlimit;
do
cur++;
while (cur < rlimit && ISIDNUM (*cur));
/* Check for slow-path cases. */
if (cur < rlimit && (*cur == '?' || *cur == '\\' || *cur == '$'))
result = parse_identifier_slow (pfile, cur);
else
{
const U_CHAR *base = pfile->buffer->cur - 1;
result = (cpp_hashnode *)
ht_lookup (pfile->hash_table, base, cur - base, HT_ALLOC);
pfile->buffer->cur = cur;
}
/* Rarely, identifiers require diagnostics when lexed.
XXX Has to be forced out of the fast path. */
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, "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)
cpp_pedwarn (pfile,
"__VA_ARGS__ can only appear in the expansion of a C99 variadic macro");
}
return result;
}
/* Slow path. This handles identifiers which have been split, and
identifiers which contain dollar signs. The part of the identifier
from PFILE->buffer->cur-1 to CUR has already been scanned. */
static cpp_hashnode *
parse_identifier_slow (pfile, cur)
cpp_reader *pfile;
const U_CHAR *cur;
{
cpp_buffer *buffer = pfile->buffer;
const U_CHAR *base = buffer->cur - 1;
struct obstack *stack = &pfile->hash_table->stack;
unsigned int c, saw_dollar = 0, len;
/* Copy the part of the token which is known to be okay. */
obstack_grow (stack, base, cur - base);
/* Now process the part which isn't. We are looking at one of
'$', '\\', or '?' on entry to this loop. */
c = *cur++;
buffer->cur = cur;
do
{
do
{
obstack_1grow (stack, c);
while (is_idchar (c))
{
obstack_1grow (stack, c);
if (c == '$')
saw_dollar++;
if (c == '$')
saw_dollar++;
c = EOF;
if (buffer->cur == buffer->rlimit)
break;
c = EOF;
if (buffer->cur == buffer->rlimit)
break;
c = *buffer->cur++;
}
while (is_idchar (c));
c = *buffer->cur++;
}
/* Potential escaped newline? */
if (c != '?' && c != '\\')
break;
break;
c = skip_escaped_newlines (pfile, c);
}
while (is_idchar (c));
@ -521,26 +584,8 @@ parse_identifier (pfile, c)
len = obstack_object_size (stack);
obstack_1grow (stack, '\0');
/* This routine commits the memory if necessary. */
result = (cpp_hashnode *)
return (cpp_hashnode *)
ht_lookup (pfile->hash_table, obstack_finish (stack), len, HT_ALLOCED);
/* Some identifiers require diagnostics when lexed. */
if (result->flags & NODE_DIAGNOSTIC && !pfile->state.skipping)
{
/* It is allowed to poison the same identifier twice. */
if ((result->flags & NODE_POISONED) && !pfile->state.poisoned_ok)
cpp_error (pfile, "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)
cpp_pedwarn (pfile, "__VA_ARGS__ can only appear in the expansion of a C99 variadic macro");
}
return result;
}
/* Parse a number, skipping embedded backslash-newlines. */
@ -1003,14 +1048,17 @@ _cpp_lex_token (pfile, result)
case 'S': case 'T': case 'U': case 'V': case 'W': case 'X':
case 'Y': case 'Z':
result->type = CPP_NAME;
result->val.node = parse_identifier (pfile, c);
result->val.node = parse_identifier (pfile);
/* 'L' may introduce wide characters or strings. */
if (result->val.node == pfile->spec_nodes.n_L)
{
c = buffer->read_ahead; /* For make_string. */
c = buffer->read_ahead;
if (c == EOF && buffer->cur < buffer->rlimit)
c = *buffer->cur;
if (c == '\'' || c == '"')
{
buffer->cur++;
ACCEPT_CHAR (c == '"' ? CPP_WSTRING: CPP_WCHAR);
goto make_string;
}

2
gcc/hashtable.c
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@ -162,7 +162,7 @@ ht_lookup (table, str, len, insert)
HT_LEN (node) = len;
if (insert == HT_ALLOC)
HT_STR (node) = obstack_copy (&table->stack, str, len + 1);
HT_STR (node) = obstack_copy0 (&table->stack, str, len);
else
HT_STR (node) = str;

7
gcc/system.h
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@ -490,6 +490,13 @@ extern void abort PARAMS ((void));
#endif /* ! __FUNCTION__ */
#endif
/* __builtin_expect(A, B) evaluates to A, but notifies the compiler that
the most likely value of A is B. This feature was added at some point
between 2.95 and 3.0. Let's use 3.0 as the lower bound for now. */
#if (GCC_VERSION < 3000)
#define __builtin_expect(a, b) (a)
#endif
/* Provide some sort of boolean type. We use stdbool.h if it's
available. This must be after all inclusion of system headers,
as some of them will mess us up. */