Revision 0ee931c4e31a5efb134c76440405e9219f896e33 authored by Michal Hocko on 13 September 2017, 23:28:29 UTC, committed by Linus Torvalds on 14 September 2017, 01:53:16 UTC
GFP_TEMPORARY was introduced by commit e12ba74d8ff3 ("Group short-lived and reclaimable kernel allocations") along with __GFP_RECLAIMABLE. It's primary motivation was to allow users to tell that an allocation is short lived and so the allocator can try to place such allocations close together and prevent long term fragmentation. As much as this sounds like a reasonable semantic it becomes much less clear when to use the highlevel GFP_TEMPORARY allocation flag. How long is temporary? Can the context holding that memory sleep? Can it take locks? It seems there is no good answer for those questions. The current implementation of GFP_TEMPORARY is basically GFP_KERNEL | __GFP_RECLAIMABLE which in itself is tricky because basically none of the existing caller provide a way to reclaim the allocated memory. So this is rather misleading and hard to evaluate for any benefits. I have checked some random users and none of them has added the flag with a specific justification. I suspect most of them just copied from other existing users and others just thought it might be a good idea to use without any measuring. This suggests that GFP_TEMPORARY just motivates for cargo cult usage without any reasoning. I believe that our gfp flags are quite complex already and especially those with highlevel semantic should be clearly defined to prevent from confusion and abuse. Therefore I propose dropping GFP_TEMPORARY and replace all existing users to simply use GFP_KERNEL. Please note that SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and so they will be placed properly for memory fragmentation prevention. I can see reasons we might want some gfp flag to reflect shorterm allocations but I propose starting from a clear semantic definition and only then add users with proper justification. This was been brought up before LSF this year by Matthew [1] and it turned out that GFP_TEMPORARY really doesn't have a clear semantic. It seems to be a heuristic without any measured advantage for most (if not all) its current users. The follow up discussion has revealed that opinions on what might be temporary allocation differ a lot between developers. So rather than trying to tweak existing users into a semantic which they haven't expected I propose to simply remove the flag and start from scratch if we really need a semantic for short term allocations. [1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org [akpm@linux-foundation.org: fix typo] [akpm@linux-foundation.org: coding-style fixes] [sfr@canb.auug.org.au: drm/i915: fix up] Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Neil Brown <neilb@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent d0dbf77
unifdef.c
/*
* Copyright (c) 2002 - 2011 Tony Finch <dot@dotat.at>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* unifdef - remove ifdef'ed lines
*
* This code was derived from software contributed to Berkeley by Dave Yost.
* It was rewritten to support ANSI C by Tony Finch. The original version
* of unifdef carried the 4-clause BSD copyright licence. None of its code
* remains in this version (though some of the names remain) so it now
* carries a more liberal licence.
*
* Wishlist:
* provide an option which will append the name of the
* appropriate symbol after #else's and #endif's
* provide an option which will check symbols after
* #else's and #endif's to see that they match their
* corresponding #ifdef or #ifndef
*
* These require better buffer handling, which would also make
* it possible to handle all "dodgy" directives correctly.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
const char copyright[] =
"@(#) $Version: unifdef-2.5 $\n"
"@(#) $Author: Tony Finch (dot@dotat.at) $\n"
"@(#) $URL: http://dotat.at/prog/unifdef $\n"
;
/* types of input lines: */
typedef enum {
LT_TRUEI, /* a true #if with ignore flag */
LT_FALSEI, /* a false #if with ignore flag */
LT_IF, /* an unknown #if */
LT_TRUE, /* a true #if */
LT_FALSE, /* a false #if */
LT_ELIF, /* an unknown #elif */
LT_ELTRUE, /* a true #elif */
LT_ELFALSE, /* a false #elif */
LT_ELSE, /* #else */
LT_ENDIF, /* #endif */
LT_DODGY, /* flag: directive is not on one line */
LT_DODGY_LAST = LT_DODGY + LT_ENDIF,
LT_PLAIN, /* ordinary line */
LT_EOF, /* end of file */
LT_ERROR, /* unevaluable #if */
LT_COUNT
} Linetype;
static char const * const linetype_name[] = {
"TRUEI", "FALSEI", "IF", "TRUE", "FALSE",
"ELIF", "ELTRUE", "ELFALSE", "ELSE", "ENDIF",
"DODGY TRUEI", "DODGY FALSEI",
"DODGY IF", "DODGY TRUE", "DODGY FALSE",
"DODGY ELIF", "DODGY ELTRUE", "DODGY ELFALSE",
"DODGY ELSE", "DODGY ENDIF",
"PLAIN", "EOF", "ERROR"
};
/* state of #if processing */
typedef enum {
IS_OUTSIDE,
IS_FALSE_PREFIX, /* false #if followed by false #elifs */
IS_TRUE_PREFIX, /* first non-false #(el)if is true */
IS_PASS_MIDDLE, /* first non-false #(el)if is unknown */
IS_FALSE_MIDDLE, /* a false #elif after a pass state */
IS_TRUE_MIDDLE, /* a true #elif after a pass state */
IS_PASS_ELSE, /* an else after a pass state */
IS_FALSE_ELSE, /* an else after a true state */
IS_TRUE_ELSE, /* an else after only false states */
IS_FALSE_TRAILER, /* #elifs after a true are false */
IS_COUNT
} Ifstate;
static char const * const ifstate_name[] = {
"OUTSIDE", "FALSE_PREFIX", "TRUE_PREFIX",
"PASS_MIDDLE", "FALSE_MIDDLE", "TRUE_MIDDLE",
"PASS_ELSE", "FALSE_ELSE", "TRUE_ELSE",
"FALSE_TRAILER"
};
/* state of comment parser */
typedef enum {
NO_COMMENT = false, /* outside a comment */
C_COMMENT, /* in a comment like this one */
CXX_COMMENT, /* between // and end of line */
STARTING_COMMENT, /* just after slash-backslash-newline */
FINISHING_COMMENT, /* star-backslash-newline in a C comment */
CHAR_LITERAL, /* inside '' */
STRING_LITERAL /* inside "" */
} Comment_state;
static char const * const comment_name[] = {
"NO", "C", "CXX", "STARTING", "FINISHING", "CHAR", "STRING"
};
/* state of preprocessor line parser */
typedef enum {
LS_START, /* only space and comments on this line */
LS_HASH, /* only space, comments, and a hash */
LS_DIRTY /* this line can't be a preprocessor line */
} Line_state;
static char const * const linestate_name[] = {
"START", "HASH", "DIRTY"
};
/*
* Minimum translation limits from ISO/IEC 9899:1999 5.2.4.1
*/
#define MAXDEPTH 64 /* maximum #if nesting */
#define MAXLINE 4096 /* maximum length of line */
#define MAXSYMS 4096 /* maximum number of symbols */
/*
* Sometimes when editing a keyword the replacement text is longer, so
* we leave some space at the end of the tline buffer to accommodate this.
*/
#define EDITSLOP 10
/*
* For temporary filenames
*/
#define TEMPLATE "unifdef.XXXXXX"
/*
* Globals.
*/
static bool compblank; /* -B: compress blank lines */
static bool lnblank; /* -b: blank deleted lines */
static bool complement; /* -c: do the complement */
static bool debugging; /* -d: debugging reports */
static bool iocccok; /* -e: fewer IOCCC errors */
static bool strictlogic; /* -K: keep ambiguous #ifs */
static bool killconsts; /* -k: eval constant #ifs */
static bool lnnum; /* -n: add #line directives */
static bool symlist; /* -s: output symbol list */
static bool symdepth; /* -S: output symbol depth */
static bool text; /* -t: this is a text file */
static const char *symname[MAXSYMS]; /* symbol name */
static const char *value[MAXSYMS]; /* -Dsym=value */
static bool ignore[MAXSYMS]; /* -iDsym or -iUsym */
static int nsyms; /* number of symbols */
static FILE *input; /* input file pointer */
static const char *filename; /* input file name */
static int linenum; /* current line number */
static FILE *output; /* output file pointer */
static const char *ofilename; /* output file name */
static bool overwriting; /* output overwrites input */
static char tempname[FILENAME_MAX]; /* used when overwriting */
static char tline[MAXLINE+EDITSLOP];/* input buffer plus space */
static char *keyword; /* used for editing #elif's */
static const char *newline; /* input file format */
static const char newline_unix[] = "\n";
static const char newline_crlf[] = "\r\n";
static Comment_state incomment; /* comment parser state */
static Line_state linestate; /* #if line parser state */
static Ifstate ifstate[MAXDEPTH]; /* #if processor state */
static bool ignoring[MAXDEPTH]; /* ignore comments state */
static int stifline[MAXDEPTH]; /* start of current #if */
static int depth; /* current #if nesting */
static int delcount; /* count of deleted lines */
static unsigned blankcount; /* count of blank lines */
static unsigned blankmax; /* maximum recent blankcount */
static bool constexpr; /* constant #if expression */
static bool zerosyms = true; /* to format symdepth output */
static bool firstsym; /* ditto */
static int exitstat; /* program exit status */
static void addsym(bool, bool, char *);
static void closeout(void);
static void debug(const char *, ...);
static void done(void);
static void error(const char *);
static int findsym(const char *);
static void flushline(bool);
static Linetype parseline(void);
static Linetype ifeval(const char **);
static void ignoreoff(void);
static void ignoreon(void);
static void keywordedit(const char *);
static void nest(void);
static void process(void);
static const char *skipargs(const char *);
static const char *skipcomment(const char *);
static const char *skipsym(const char *);
static void state(Ifstate);
static int strlcmp(const char *, const char *, size_t);
static void unnest(void);
static void usage(void);
static void version(void);
#define endsym(c) (!isalnum((unsigned char)c) && c != '_')
/*
* The main program.
*/
int
main(int argc, char *argv[])
{
int opt;
while ((opt = getopt(argc, argv, "i:D:U:I:o:bBcdeKklnsStV")) != -1)
switch (opt) {
case 'i': /* treat stuff controlled by these symbols as text */
/*
* For strict backwards-compatibility the U or D
* should be immediately after the -i but it doesn't
* matter much if we relax that requirement.
*/
opt = *optarg++;
if (opt == 'D')
addsym(true, true, optarg);
else if (opt == 'U')
addsym(true, false, optarg);
else
usage();
break;
case 'D': /* define a symbol */
addsym(false, true, optarg);
break;
case 'U': /* undef a symbol */
addsym(false, false, optarg);
break;
case 'I': /* no-op for compatibility with cpp */
break;
case 'b': /* blank deleted lines instead of omitting them */
case 'l': /* backwards compatibility */
lnblank = true;
break;
case 'B': /* compress blank lines around removed section */
compblank = true;
break;
case 'c': /* treat -D as -U and vice versa */
complement = true;
break;
case 'd':
debugging = true;
break;
case 'e': /* fewer errors from dodgy lines */
iocccok = true;
break;
case 'K': /* keep ambiguous #ifs */
strictlogic = true;
break;
case 'k': /* process constant #ifs */
killconsts = true;
break;
case 'n': /* add #line directive after deleted lines */
lnnum = true;
break;
case 'o': /* output to a file */
ofilename = optarg;
break;
case 's': /* only output list of symbols that control #ifs */
symlist = true;
break;
case 'S': /* list symbols with their nesting depth */
symlist = symdepth = true;
break;
case 't': /* don't parse C comments */
text = true;
break;
case 'V': /* print version */
version();
default:
usage();
}
argc -= optind;
argv += optind;
if (compblank && lnblank)
errx(2, "-B and -b are mutually exclusive");
if (argc > 1) {
errx(2, "can only do one file");
} else if (argc == 1 && strcmp(*argv, "-") != 0) {
filename = *argv;
input = fopen(filename, "rb");
if (input == NULL)
err(2, "can't open %s", filename);
} else {
filename = "[stdin]";
input = stdin;
}
if (ofilename == NULL) {
ofilename = "[stdout]";
output = stdout;
} else {
struct stat ist, ost;
if (stat(ofilename, &ost) == 0 &&
fstat(fileno(input), &ist) == 0)
overwriting = (ist.st_dev == ost.st_dev
&& ist.st_ino == ost.st_ino);
if (overwriting) {
const char *dirsep;
int ofd;
dirsep = strrchr(ofilename, '/');
if (dirsep != NULL)
snprintf(tempname, sizeof(tempname),
"%.*s/" TEMPLATE,
(int)(dirsep - ofilename), ofilename);
else
snprintf(tempname, sizeof(tempname),
TEMPLATE);
ofd = mkstemp(tempname);
if (ofd != -1)
output = fdopen(ofd, "wb+");
if (output == NULL)
err(2, "can't create temporary file");
fchmod(ofd, ist.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO));
} else {
output = fopen(ofilename, "wb");
if (output == NULL)
err(2, "can't open %s", ofilename);
}
}
process();
abort(); /* bug */
}
static void
version(void)
{
const char *c = copyright;
for (;;) {
while (*++c != '$')
if (*c == '\0')
exit(0);
while (*++c != '$')
putc(*c, stderr);
putc('\n', stderr);
}
}
static void
usage(void)
{
fprintf(stderr, "usage: unifdef [-bBcdeKknsStV] [-Ipath]"
" [-Dsym[=val]] [-Usym] [-iDsym[=val]] [-iUsym] ... [file]\n");
exit(2);
}
/*
* A state transition function alters the global #if processing state
* in a particular way. The table below is indexed by the current
* processing state and the type of the current line.
*
* Nesting is handled by keeping a stack of states; some transition
* functions increase or decrease the depth. They also maintain the
* ignore state on a stack. In some complicated cases they have to
* alter the preprocessor directive, as follows.
*
* When we have processed a group that starts off with a known-false
* #if/#elif sequence (which has therefore been deleted) followed by a
* #elif that we don't understand and therefore must keep, we edit the
* latter into a #if to keep the nesting correct. We use strncpy() to
* overwrite the 4 byte token "elif" with "if " without a '\0' byte.
*
* When we find a true #elif in a group, the following block will
* always be kept and the rest of the sequence after the next #elif or
* #else will be discarded. We edit the #elif into a #else and the
* following directive to #endif since this has the desired behaviour.
*
* "Dodgy" directives are split across multiple lines, the most common
* example being a multi-line comment hanging off the right of the
* directive. We can handle them correctly only if there is no change
* from printing to dropping (or vice versa) caused by that directive.
* If the directive is the first of a group we have a choice between
* failing with an error, or passing it through unchanged instead of
* evaluating it. The latter is not the default to avoid questions from
* users about unifdef unexpectedly leaving behind preprocessor directives.
*/
typedef void state_fn(void);
/* report an error */
static void Eelif (void) { error("Inappropriate #elif"); }
static void Eelse (void) { error("Inappropriate #else"); }
static void Eendif(void) { error("Inappropriate #endif"); }
static void Eeof (void) { error("Premature EOF"); }
static void Eioccc(void) { error("Obfuscated preprocessor control line"); }
/* plain line handling */
static void print (void) { flushline(true); }
static void drop (void) { flushline(false); }
/* output lacks group's start line */
static void Strue (void) { drop(); ignoreoff(); state(IS_TRUE_PREFIX); }
static void Sfalse(void) { drop(); ignoreoff(); state(IS_FALSE_PREFIX); }
static void Selse (void) { drop(); state(IS_TRUE_ELSE); }
/* print/pass this block */
static void Pelif (void) { print(); ignoreoff(); state(IS_PASS_MIDDLE); }
static void Pelse (void) { print(); state(IS_PASS_ELSE); }
static void Pendif(void) { print(); unnest(); }
/* discard this block */
static void Dfalse(void) { drop(); ignoreoff(); state(IS_FALSE_TRAILER); }
static void Delif (void) { drop(); ignoreoff(); state(IS_FALSE_MIDDLE); }
static void Delse (void) { drop(); state(IS_FALSE_ELSE); }
static void Dendif(void) { drop(); unnest(); }
/* first line of group */
static void Fdrop (void) { nest(); Dfalse(); }
static void Fpass (void) { nest(); Pelif(); }
static void Ftrue (void) { nest(); Strue(); }
static void Ffalse(void) { nest(); Sfalse(); }
/* variable pedantry for obfuscated lines */
static void Oiffy (void) { if (!iocccok) Eioccc(); Fpass(); ignoreon(); }
static void Oif (void) { if (!iocccok) Eioccc(); Fpass(); }
static void Oelif (void) { if (!iocccok) Eioccc(); Pelif(); }
/* ignore comments in this block */
static void Idrop (void) { Fdrop(); ignoreon(); }
static void Itrue (void) { Ftrue(); ignoreon(); }
static void Ifalse(void) { Ffalse(); ignoreon(); }
/* modify this line */
static void Mpass (void) { strncpy(keyword, "if ", 4); Pelif(); }
static void Mtrue (void) { keywordedit("else"); state(IS_TRUE_MIDDLE); }
static void Melif (void) { keywordedit("endif"); state(IS_FALSE_TRAILER); }
static void Melse (void) { keywordedit("endif"); state(IS_FALSE_ELSE); }
static state_fn * const trans_table[IS_COUNT][LT_COUNT] = {
/* IS_OUTSIDE */
{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Eendif,
Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eendif,
print, done, abort },
/* IS_FALSE_PREFIX */
{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Strue, Sfalse,Selse, Dendif,
Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Eioccc,Eioccc,Eioccc,Eioccc,
drop, Eeof, abort },
/* IS_TRUE_PREFIX */
{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Dfalse,Dfalse,Dfalse,Delse, Dendif,
Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc,
print, Eeof, abort },
/* IS_PASS_MIDDLE */
{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Pelif, Mtrue, Delif, Pelse, Pendif,
Oiffy, Oiffy, Fpass, Oif, Oif, Pelif, Oelif, Oelif, Pelse, Pendif,
print, Eeof, abort },
/* IS_FALSE_MIDDLE */
{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Pelif, Mtrue, Delif, Pelse, Pendif,
Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc,
drop, Eeof, abort },
/* IS_TRUE_MIDDLE */
{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Melif, Melif, Melif, Melse, Pendif,
Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Pendif,
print, Eeof, abort },
/* IS_PASS_ELSE */
{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Pendif,
Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Pendif,
print, Eeof, abort },
/* IS_FALSE_ELSE */
{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Dendif,
Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Eioccc,
drop, Eeof, abort },
/* IS_TRUE_ELSE */
{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Dendif,
Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eioccc,
print, Eeof, abort },
/* IS_FALSE_TRAILER */
{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Dendif,
Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Eioccc,
drop, Eeof, abort }
/*TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF
TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF (DODGY)
PLAIN EOF ERROR */
};
/*
* State machine utility functions
*/
static void
ignoreoff(void)
{
if (depth == 0)
abort(); /* bug */
ignoring[depth] = ignoring[depth-1];
}
static void
ignoreon(void)
{
ignoring[depth] = true;
}
static void
keywordedit(const char *replacement)
{
snprintf(keyword, tline + sizeof(tline) - keyword,
"%s%s", replacement, newline);
print();
}
static void
nest(void)
{
if (depth > MAXDEPTH-1)
abort(); /* bug */
if (depth == MAXDEPTH-1)
error("Too many levels of nesting");
depth += 1;
stifline[depth] = linenum;
}
static void
unnest(void)
{
if (depth == 0)
abort(); /* bug */
depth -= 1;
}
static void
state(Ifstate is)
{
ifstate[depth] = is;
}
/*
* Write a line to the output or not, according to command line options.
*/
static void
flushline(bool keep)
{
if (symlist)
return;
if (keep ^ complement) {
bool blankline = tline[strspn(tline, " \t\r\n")] == '\0';
if (blankline && compblank && blankcount != blankmax) {
delcount += 1;
blankcount += 1;
} else {
if (lnnum && delcount > 0)
printf("#line %d%s", linenum, newline);
fputs(tline, output);
delcount = 0;
blankmax = blankcount = blankline ? blankcount + 1 : 0;
}
} else {
if (lnblank)
fputs(newline, output);
exitstat = 1;
delcount += 1;
blankcount = 0;
}
if (debugging)
fflush(output);
}
/*
* The driver for the state machine.
*/
static void
process(void)
{
/* When compressing blank lines, act as if the file
is preceded by a large number of blank lines. */
blankmax = blankcount = 1000;
for (;;) {
Linetype lineval = parseline();
trans_table[ifstate[depth]][lineval]();
debug("process line %d %s -> %s depth %d",
linenum, linetype_name[lineval],
ifstate_name[ifstate[depth]], depth);
}
}
/*
* Flush the output and handle errors.
*/
static void
closeout(void)
{
if (symdepth && !zerosyms)
printf("\n");
if (fclose(output) == EOF) {
warn("couldn't write to %s", ofilename);
if (overwriting) {
unlink(tempname);
errx(2, "%s unchanged", filename);
} else {
exit(2);
}
}
}
/*
* Clean up and exit.
*/
static void
done(void)
{
if (incomment)
error("EOF in comment");
closeout();
if (overwriting && rename(tempname, ofilename) == -1) {
warn("couldn't rename temporary file");
unlink(tempname);
errx(2, "%s unchanged", ofilename);
}
exit(exitstat);
}
/*
* Parse a line and determine its type. We keep the preprocessor line
* parser state between calls in the global variable linestate, with
* help from skipcomment().
*/
static Linetype
parseline(void)
{
const char *cp;
int cursym;
int kwlen;
Linetype retval;
Comment_state wascomment;
linenum++;
if (fgets(tline, MAXLINE, input) == NULL)
return (LT_EOF);
if (newline == NULL) {
if (strrchr(tline, '\n') == strrchr(tline, '\r') + 1)
newline = newline_crlf;
else
newline = newline_unix;
}
retval = LT_PLAIN;
wascomment = incomment;
cp = skipcomment(tline);
if (linestate == LS_START) {
if (*cp == '#') {
linestate = LS_HASH;
firstsym = true;
cp = skipcomment(cp + 1);
} else if (*cp != '\0')
linestate = LS_DIRTY;
}
if (!incomment && linestate == LS_HASH) {
keyword = tline + (cp - tline);
cp = skipsym(cp);
kwlen = cp - keyword;
/* no way can we deal with a continuation inside a keyword */
if (strncmp(cp, "\\\r\n", 3) == 0 ||
strncmp(cp, "\\\n", 2) == 0)
Eioccc();
if (strlcmp("ifdef", keyword, kwlen) == 0 ||
strlcmp("ifndef", keyword, kwlen) == 0) {
cp = skipcomment(cp);
if ((cursym = findsym(cp)) < 0)
retval = LT_IF;
else {
retval = (keyword[2] == 'n')
? LT_FALSE : LT_TRUE;
if (value[cursym] == NULL)
retval = (retval == LT_TRUE)
? LT_FALSE : LT_TRUE;
if (ignore[cursym])
retval = (retval == LT_TRUE)
? LT_TRUEI : LT_FALSEI;
}
cp = skipsym(cp);
} else if (strlcmp("if", keyword, kwlen) == 0)
retval = ifeval(&cp);
else if (strlcmp("elif", keyword, kwlen) == 0)
retval = ifeval(&cp) - LT_IF + LT_ELIF;
else if (strlcmp("else", keyword, kwlen) == 0)
retval = LT_ELSE;
else if (strlcmp("endif", keyword, kwlen) == 0)
retval = LT_ENDIF;
else {
linestate = LS_DIRTY;
retval = LT_PLAIN;
}
cp = skipcomment(cp);
if (*cp != '\0') {
linestate = LS_DIRTY;
if (retval == LT_TRUE || retval == LT_FALSE ||
retval == LT_TRUEI || retval == LT_FALSEI)
retval = LT_IF;
if (retval == LT_ELTRUE || retval == LT_ELFALSE)
retval = LT_ELIF;
}
if (retval != LT_PLAIN && (wascomment || incomment)) {
retval += LT_DODGY;
if (incomment)
linestate = LS_DIRTY;
}
/* skipcomment normally changes the state, except
if the last line of the file lacks a newline, or
if there is too much whitespace in a directive */
if (linestate == LS_HASH) {
size_t len = cp - tline;
if (fgets(tline + len, MAXLINE - len, input) == NULL) {
/* append the missing newline */
strcpy(tline + len, newline);
cp += strlen(newline);
linestate = LS_START;
} else {
linestate = LS_DIRTY;
}
}
}
if (linestate == LS_DIRTY) {
while (*cp != '\0')
cp = skipcomment(cp + 1);
}
debug("parser line %d state %s comment %s line", linenum,
comment_name[incomment], linestate_name[linestate]);
return (retval);
}
/*
* These are the binary operators that are supported by the expression
* evaluator.
*/
static Linetype op_strict(int *p, int v, Linetype at, Linetype bt) {
if(at == LT_IF || bt == LT_IF) return (LT_IF);
return (*p = v, v ? LT_TRUE : LT_FALSE);
}
static Linetype op_lt(int *p, Linetype at, int a, Linetype bt, int b) {
return op_strict(p, a < b, at, bt);
}
static Linetype op_gt(int *p, Linetype at, int a, Linetype bt, int b) {
return op_strict(p, a > b, at, bt);
}
static Linetype op_le(int *p, Linetype at, int a, Linetype bt, int b) {
return op_strict(p, a <= b, at, bt);
}
static Linetype op_ge(int *p, Linetype at, int a, Linetype bt, int b) {
return op_strict(p, a >= b, at, bt);
}
static Linetype op_eq(int *p, Linetype at, int a, Linetype bt, int b) {
return op_strict(p, a == b, at, bt);
}
static Linetype op_ne(int *p, Linetype at, int a, Linetype bt, int b) {
return op_strict(p, a != b, at, bt);
}
static Linetype op_or(int *p, Linetype at, int a, Linetype bt, int b) {
if (!strictlogic && (at == LT_TRUE || bt == LT_TRUE))
return (*p = 1, LT_TRUE);
return op_strict(p, a || b, at, bt);
}
static Linetype op_and(int *p, Linetype at, int a, Linetype bt, int b) {
if (!strictlogic && (at == LT_FALSE || bt == LT_FALSE))
return (*p = 0, LT_FALSE);
return op_strict(p, a && b, at, bt);
}
/*
* An evaluation function takes three arguments, as follows: (1) a pointer to
* an element of the precedence table which lists the operators at the current
* level of precedence; (2) a pointer to an integer which will receive the
* value of the expression; and (3) a pointer to a char* that points to the
* expression to be evaluated and that is updated to the end of the expression
* when evaluation is complete. The function returns LT_FALSE if the value of
* the expression is zero, LT_TRUE if it is non-zero, LT_IF if the expression
* depends on an unknown symbol, or LT_ERROR if there is a parse failure.
*/
struct ops;
typedef Linetype eval_fn(const struct ops *, int *, const char **);
static eval_fn eval_table, eval_unary;
/*
* The precedence table. Expressions involving binary operators are evaluated
* in a table-driven way by eval_table. When it evaluates a subexpression it
* calls the inner function with its first argument pointing to the next
* element of the table. Innermost expressions have special non-table-driven
* handling.
*/
static const struct ops {
eval_fn *inner;
struct op {
const char *str;
Linetype (*fn)(int *, Linetype, int, Linetype, int);
} op[5];
} eval_ops[] = {
{ eval_table, { { "||", op_or } } },
{ eval_table, { { "&&", op_and } } },
{ eval_table, { { "==", op_eq },
{ "!=", op_ne } } },
{ eval_unary, { { "<=", op_le },
{ ">=", op_ge },
{ "<", op_lt },
{ ">", op_gt } } }
};
/*
* Function for evaluating the innermost parts of expressions,
* viz. !expr (expr) number defined(symbol) symbol
* We reset the constexpr flag in the last two cases.
*/
static Linetype
eval_unary(const struct ops *ops, int *valp, const char **cpp)
{
const char *cp;
char *ep;
int sym;
bool defparen;
Linetype lt;
cp = skipcomment(*cpp);
if (*cp == '!') {
debug("eval%d !", ops - eval_ops);
cp++;
lt = eval_unary(ops, valp, &cp);
if (lt == LT_ERROR)
return (LT_ERROR);
if (lt != LT_IF) {
*valp = !*valp;
lt = *valp ? LT_TRUE : LT_FALSE;
}
} else if (*cp == '(') {
cp++;
debug("eval%d (", ops - eval_ops);
lt = eval_table(eval_ops, valp, &cp);
if (lt == LT_ERROR)
return (LT_ERROR);
cp = skipcomment(cp);
if (*cp++ != ')')
return (LT_ERROR);
} else if (isdigit((unsigned char)*cp)) {
debug("eval%d number", ops - eval_ops);
*valp = strtol(cp, &ep, 0);
if (ep == cp)
return (LT_ERROR);
lt = *valp ? LT_TRUE : LT_FALSE;
cp = skipsym(cp);
} else if (strncmp(cp, "defined", 7) == 0 && endsym(cp[7])) {
cp = skipcomment(cp+7);
debug("eval%d defined", ops - eval_ops);
if (*cp == '(') {
cp = skipcomment(cp+1);
defparen = true;
} else {
defparen = false;
}
sym = findsym(cp);
if (sym < 0) {
lt = LT_IF;
} else {
*valp = (value[sym] != NULL);
lt = *valp ? LT_TRUE : LT_FALSE;
}
cp = skipsym(cp);
cp = skipcomment(cp);
if (defparen && *cp++ != ')')
return (LT_ERROR);
constexpr = false;
} else if (!endsym(*cp)) {
debug("eval%d symbol", ops - eval_ops);
sym = findsym(cp);
cp = skipsym(cp);
if (sym < 0) {
lt = LT_IF;
cp = skipargs(cp);
} else if (value[sym] == NULL) {
*valp = 0;
lt = LT_FALSE;
} else {
*valp = strtol(value[sym], &ep, 0);
if (*ep != '\0' || ep == value[sym])
return (LT_ERROR);
lt = *valp ? LT_TRUE : LT_FALSE;
cp = skipargs(cp);
}
constexpr = false;
} else {
debug("eval%d bad expr", ops - eval_ops);
return (LT_ERROR);
}
*cpp = cp;
debug("eval%d = %d", ops - eval_ops, *valp);
return (lt);
}
/*
* Table-driven evaluation of binary operators.
*/
static Linetype
eval_table(const struct ops *ops, int *valp, const char **cpp)
{
const struct op *op;
const char *cp;
int val;
Linetype lt, rt;
debug("eval%d", ops - eval_ops);
cp = *cpp;
lt = ops->inner(ops+1, valp, &cp);
if (lt == LT_ERROR)
return (LT_ERROR);
for (;;) {
cp = skipcomment(cp);
for (op = ops->op; op->str != NULL; op++)
if (strncmp(cp, op->str, strlen(op->str)) == 0)
break;
if (op->str == NULL)
break;
cp += strlen(op->str);
debug("eval%d %s", ops - eval_ops, op->str);
rt = ops->inner(ops+1, &val, &cp);
if (rt == LT_ERROR)
return (LT_ERROR);
lt = op->fn(valp, lt, *valp, rt, val);
}
*cpp = cp;
debug("eval%d = %d", ops - eval_ops, *valp);
debug("eval%d lt = %s", ops - eval_ops, linetype_name[lt]);
return (lt);
}
/*
* Evaluate the expression on a #if or #elif line. If we can work out
* the result we return LT_TRUE or LT_FALSE accordingly, otherwise we
* return just a generic LT_IF.
*/
static Linetype
ifeval(const char **cpp)
{
int ret;
int val = 0;
debug("eval %s", *cpp);
constexpr = killconsts ? false : true;
ret = eval_table(eval_ops, &val, cpp);
debug("eval = %d", val);
return (constexpr ? LT_IF : ret == LT_ERROR ? LT_IF : ret);
}
/*
* Skip over comments, strings, and character literals and stop at the
* next character position that is not whitespace. Between calls we keep
* the comment state in the global variable incomment, and we also adjust
* the global variable linestate when we see a newline.
* XXX: doesn't cope with the buffer splitting inside a state transition.
*/
static const char *
skipcomment(const char *cp)
{
if (text || ignoring[depth]) {
for (; isspace((unsigned char)*cp); cp++)
if (*cp == '\n')
linestate = LS_START;
return (cp);
}
while (*cp != '\0')
/* don't reset to LS_START after a line continuation */
if (strncmp(cp, "\\\r\n", 3) == 0)
cp += 3;
else if (strncmp(cp, "\\\n", 2) == 0)
cp += 2;
else switch (incomment) {
case NO_COMMENT:
if (strncmp(cp, "/\\\r\n", 4) == 0) {
incomment = STARTING_COMMENT;
cp += 4;
} else if (strncmp(cp, "/\\\n", 3) == 0) {
incomment = STARTING_COMMENT;
cp += 3;
} else if (strncmp(cp, "/*", 2) == 0) {
incomment = C_COMMENT;
cp += 2;
} else if (strncmp(cp, "//", 2) == 0) {
incomment = CXX_COMMENT;
cp += 2;
} else if (strncmp(cp, "\'", 1) == 0) {
incomment = CHAR_LITERAL;
linestate = LS_DIRTY;
cp += 1;
} else if (strncmp(cp, "\"", 1) == 0) {
incomment = STRING_LITERAL;
linestate = LS_DIRTY;
cp += 1;
} else if (strncmp(cp, "\n", 1) == 0) {
linestate = LS_START;
cp += 1;
} else if (strchr(" \r\t", *cp) != NULL) {
cp += 1;
} else
return (cp);
continue;
case CXX_COMMENT:
if (strncmp(cp, "\n", 1) == 0) {
incomment = NO_COMMENT;
linestate = LS_START;
}
cp += 1;
continue;
case CHAR_LITERAL:
case STRING_LITERAL:
if ((incomment == CHAR_LITERAL && cp[0] == '\'') ||
(incomment == STRING_LITERAL && cp[0] == '\"')) {
incomment = NO_COMMENT;
cp += 1;
} else if (cp[0] == '\\') {
if (cp[1] == '\0')
cp += 1;
else
cp += 2;
} else if (strncmp(cp, "\n", 1) == 0) {
if (incomment == CHAR_LITERAL)
error("unterminated char literal");
else
error("unterminated string literal");
} else
cp += 1;
continue;
case C_COMMENT:
if (strncmp(cp, "*\\\r\n", 4) == 0) {
incomment = FINISHING_COMMENT;
cp += 4;
} else if (strncmp(cp, "*\\\n", 3) == 0) {
incomment = FINISHING_COMMENT;
cp += 3;
} else if (strncmp(cp, "*/", 2) == 0) {
incomment = NO_COMMENT;
cp += 2;
} else
cp += 1;
continue;
case STARTING_COMMENT:
if (*cp == '*') {
incomment = C_COMMENT;
cp += 1;
} else if (*cp == '/') {
incomment = CXX_COMMENT;
cp += 1;
} else {
incomment = NO_COMMENT;
linestate = LS_DIRTY;
}
continue;
case FINISHING_COMMENT:
if (*cp == '/') {
incomment = NO_COMMENT;
cp += 1;
} else
incomment = C_COMMENT;
continue;
default:
abort(); /* bug */
}
return (cp);
}
/*
* Skip macro arguments.
*/
static const char *
skipargs(const char *cp)
{
const char *ocp = cp;
int level = 0;
cp = skipcomment(cp);
if (*cp != '(')
return (cp);
do {
if (*cp == '(')
level++;
if (*cp == ')')
level--;
cp = skipcomment(cp+1);
} while (level != 0 && *cp != '\0');
if (level == 0)
return (cp);
else
/* Rewind and re-detect the syntax error later. */
return (ocp);
}
/*
* Skip over an identifier.
*/
static const char *
skipsym(const char *cp)
{
while (!endsym(*cp))
++cp;
return (cp);
}
/*
* Look for the symbol in the symbol table. If it is found, we return
* the symbol table index, else we return -1.
*/
static int
findsym(const char *str)
{
const char *cp;
int symind;
cp = skipsym(str);
if (cp == str)
return (-1);
if (symlist) {
if (symdepth && firstsym)
printf("%s%3d", zerosyms ? "" : "\n", depth);
firstsym = zerosyms = false;
printf("%s%.*s%s",
symdepth ? " " : "",
(int)(cp-str), str,
symdepth ? "" : "\n");
/* we don't care about the value of the symbol */
return (0);
}
for (symind = 0; symind < nsyms; ++symind) {
if (strlcmp(symname[symind], str, cp-str) == 0) {
debug("findsym %s %s", symname[symind],
value[symind] ? value[symind] : "");
return (symind);
}
}
return (-1);
}
/*
* Add a symbol to the symbol table.
*/
static void
addsym(bool ignorethis, bool definethis, char *sym)
{
int symind;
char *val;
symind = findsym(sym);
if (symind < 0) {
if (nsyms >= MAXSYMS)
errx(2, "too many symbols");
symind = nsyms++;
}
symname[symind] = sym;
ignore[symind] = ignorethis;
val = sym + (skipsym(sym) - sym);
if (definethis) {
if (*val == '=') {
value[symind] = val+1;
*val = '\0';
} else if (*val == '\0')
value[symind] = "1";
else
usage();
} else {
if (*val != '\0')
usage();
value[symind] = NULL;
}
debug("addsym %s=%s", symname[symind],
value[symind] ? value[symind] : "undef");
}
/*
* Compare s with n characters of t.
* The same as strncmp() except that it checks that s[n] == '\0'.
*/
static int
strlcmp(const char *s, const char *t, size_t n)
{
while (n-- && *t != '\0')
if (*s != *t)
return ((unsigned char)*s - (unsigned char)*t);
else
++s, ++t;
return ((unsigned char)*s);
}
/*
* Diagnostics.
*/
static void
debug(const char *msg, ...)
{
va_list ap;
if (debugging) {
va_start(ap, msg);
vwarnx(msg, ap);
va_end(ap);
}
}
static void
error(const char *msg)
{
if (depth == 0)
warnx("%s: %d: %s", filename, linenum, msg);
else
warnx("%s: %d: %s (#if line %d depth %d)",
filename, linenum, msg, stifline[depth], depth);
closeout();
errx(2, "output may be truncated");
}
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