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Makefile.in (cppexp.o): Depend on cpphash.h.

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* Makefile.in (cppexp.o): Depend on cpphash.h.
	* cppexp.c (cpp_lex): Handle `defined (xxx)' for poisoned xxx.
	Include cpphash.h.
	* cpphash.c (special_symbol): Handle plain `xxx' for poisoned xxx.
	* cpplib.c (do_define): Generalise to handle poisoned definitions,
	redefining poisoned identifiers, etc.
	(do_undef): Don't allow poisoned identifiers to be undefined.
	(do_pragma): Add #pragma poison.
	(do_xifdef): Handle `#ifdef xxx' for poisoned xxx.

	* cccp.c: Add T_POISON node type.
	(special_symbol): Handle `defined(xxx)' and plain `xxx' for
	poisoned xxx.
	(do_define): Generalise to handle poisoned definitions,
	redefining poisoned identifiers, etc.
	(do_undef): Don't allow poisoned identifiers to be undefined.
	(do_pragma): Add #pragma poison.
	(do_xifdef): Handle `#ifdef xxx' for poisoned xxx.

	* c-pragma.c (handle_pragma_token): Ignore #pragma poison.
	* c-pragma.h: Add ps_poison state.  We now always have generic
	pragmas.

From-SVN: r29224
This commit is contained in:
Geoff Keating 1999-09-09 04:00:37 +00:00 committed by Geoffrey Keating
parent d60f72aec5
commit fc009f966c
13 changed files with 304 additions and 50 deletions
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25
gcc/ChangeLog
View File

@ -1,3 +1,28 @@
Thu Sep 9 13:46:06 1999 Geoffrey Keating <geoffk@cygnus.com>
* Makefile.in (cppexp.o): Depend on cpphash.h.
* cppexp.c (cpp_lex): Handle `defined (xxx)' for poisoned xxx.
Include cpphash.h.
* cpphash.c (special_symbol): Handle plain `xxx' for poisoned xxx.
* cpplib.c (do_define): Generalise to handle poisoned definitions,
redefining poisoned identifiers, etc.
(do_undef): Don't allow poisoned identifiers to be undefined.
(do_pragma): Add #pragma poison.
(do_xifdef): Handle `#ifdef xxx' for poisoned xxx.
* cccp.c: Add T_POISON node type.
(special_symbol): Handle `defined(xxx)' and plain `xxx' for
poisoned xxx.
(do_define): Generalise to handle poisoned definitions,
redefining poisoned identifiers, etc.
(do_undef): Don't allow poisoned identifiers to be undefined.
(do_pragma): Add #pragma poison.
(do_xifdef): Handle `#ifdef xxx' for poisoned xxx.
* c-pragma.c (handle_pragma_token): Ignore #pragma poison.
* c-pragma.h: Add ps_poison state. We now always have generic
pragmas.
Wed Sep 8 20:30:42 1999 Mark Mitchell <mark@codesourcery.com>
* ggc.h (ggc_alloc): New function.

2
gcc/Makefile.in
View File

@ -2019,7 +2019,7 @@ cpplib.o: cpplib.c $(CONFIG_H) cpplib.h intl.h system.h cpphash.h
cpphash.o: cpphash.c $(CONFIG_H) cpplib.h intl.h system.h cpphash.h
cppalloc.o: cppalloc.c $(CONFIG_H) cpplib.h intl.h system.h
cpperror.o: cpperror.c $(CONFIG_H) cpplib.h intl.h system.h
cppexp.o: cppexp.c $(CONFIG_H) cpplib.h intl.h system.h
cppexp.o: cppexp.c $(CONFIG_H) cpplib.h intl.h system.h cpphash.h
cppfiles.o: cppfiles.c $(CONFIG_H) cpplib.h intl.h system.h
cppinit.o: cppinit.c $(CONFIG_H) cpplib.h intl.h system.h \

11
gcc/c-pragma.c
View File

@ -300,6 +300,10 @@ handle_pragma_token (string, token)
ret_val = 1; /* Ignore the pragma. */
break;
#endif /* HANDLE_PRAGMA_WEAK */
case ps_poison:
ret_val = 1;
break;
}
type = state = ps_start;
@ -339,6 +343,8 @@ handle_pragma_token (string, token)
if (strcmp (string, "weak") == 0)
type = state = ps_weak;
#endif
if (strcmp (string, "poison") == 0)
type = state = ps_poison;
break;
#ifdef HANDLE_PRAGMA_WEAK
@ -486,6 +492,11 @@ handle_pragma_token (string, token)
break;
#endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
case ps_poison:
if (token && TREE_CODE (token) != IDENTIFIER_NODE)
state = ps_bad;
break;
case ps_bad:
case ps_done:
break;

6
gcc/c-pragma.h
View File

@ -61,13 +61,12 @@ extern int add_weak PROTO((char *, char *));
#endif /* HANDLE_PRAGMA_WEAK */
#if defined HANDLE_PRAGMA_PACK || defined HANDLE_PRAGMA_WEAK
/* Define HANDLE_GENERIC_PRAGMAS if any kind of front-end pragma
parsing is to be done. The code in GCC's generic C source files
will only look for the definition of this constant. They will
ignore definitions of HANDLE_PRAGMA_PACK and so on. */
ignore definitions of HANDLE_PRAGMA_PACK and so on.
With #pragma poison, this is always set. */
#define HANDLE_GENERIC_PRAGMAS 1
#endif
#ifdef HANDLE_GENERIC_PRAGMAS
@ -91,6 +90,7 @@ enum pragma_state
ps_push, ps_pushcomma, ps_pushid, ps_pushcomma2,
ps_pop, ps_popcomma,
#endif
ps_poison,
ps_bad
};

72
gcc/cccp.c
View File

@ -640,6 +640,7 @@ enum node_type {
T_DISABLED, /* macro temporarily turned off for rescan */
T_SPEC_DEFINED, /* special `defined' macro for use in #if statements */
T_PCSTRING, /* precompiled string (hashval is KEYDEF *) */
T_POISON, /* defined with `#pragma poison' */
T_UNUSED /* Used for something not defined. */
};
@ -4281,8 +4282,13 @@ special_symbol (hp, op)
|| (hp->type == T_MACRO && hp->value.defn->predefined)))
/* Output a precondition for this macro use. */
fprintf (pcp_outfile, "#define %s\n", hp->name);
if (hp->type == T_POISON) {
error("attempt to use poisoned `%s'.", hp->name);
buf = " 0 ";
} else {
buf = " 1 ";
}
}
else
if (pcp_outfile && pcp_inside_if) {
/* Output a precondition for this macro use */
@ -4302,6 +4308,11 @@ special_symbol (hp, op)
}
break;
case T_POISON:
error("attempt to use poisoned `%s'.", hp->name);
buf = " 0 "; /* Consider poisoned symbol to not be defined */
break;
oops:
error ("`defined' without an identifier");
@ -5926,6 +5937,7 @@ do_define (buf, limit, op, keyword)
{
int hashcode;
MACRODEF mdef;
enum node_type newtype = keyword->type == T_DEFINE ? T_MACRO : T_POISON;
/* If this is a precompiler run (with -pcp) pass thru #define directives. */
if (pcp_outfile && op)
@ -5944,19 +5956,31 @@ do_define (buf, limit, op, keyword)
/* Redefining a precompiled key is ok. */
if (hp->type == T_PCSTRING)
ok = 1;
/* Redefining a poisoned identifier is even worse than `not ok'. */
else if (hp->type == T_POISON)
ok = -1;
/* Poisoning anything else is not ok.
The poison should always come first. */
else if (newtype == T_POISON)
ok = 0;
/* Redefining a macro is ok if the definitions are the same. */
else if (hp->type == T_MACRO)
ok = ! compare_defs (mdef.defn, hp->value.defn);
/* Redefining a constant is ok with -D. */
else if (hp->type == T_CONST)
ok = ! done_initializing;
/* Print the warning if it's not ok. */
if (!ok) {
/* Print the warning or error if it's not ok. */
if (ok <= 0)
{
/* If we are passing through #define and #undef directives, do
that for this re-definition now. */
if (debug_output && op)
pass_thru_directive (buf, limit, op, keyword);
if (hp->type == T_POISON)
error ("redefining poisoned `%.*s'", mdef.symlen, mdef.symnam);
else
pedwarn ("`%.*s' redefined", mdef.symlen, mdef.symnam);
if (hp->type == T_MACRO)
pedwarn_with_file_and_line (hp->value.defn->file,
@ -5964,15 +5988,18 @@ do_define (buf, limit, op, keyword)
hp->value.defn->line,
"this is the location of the previous definition");
}
if (hp->type != T_POISON)
{
/* Replace the old definition. */
hp->type = T_MACRO;
hp->type = newtype;
hp->value.defn = mdef.defn;
}
} else {
/* If we are passing through #define and #undef directives, do
that for this new definition now. */
if (debug_output && op)
pass_thru_directive (buf, limit, op, keyword);
install (mdef.symnam, mdef.symlen, T_MACRO,
install (mdef.symnam, mdef.symlen, newtype,
(char *) mdef.defn, hashcode);
}
}
@ -6990,10 +7017,14 @@ do_undef (buf, limit, op, keyword)
need to pass through all effective #undef directives. */
if (debug_output && op)
pass_thru_directive (orig_buf, limit, op, keyword);
if (hp->type == T_POISON)
error ("cannot undefine poisoned `%s'", hp->name);
else {
if (hp->type != T_MACRO)
warning ("undefining `%s'", hp->name);
delete_macro (hp);
}
}
if (pedantic) {
buf += sym_length;
@ -7087,9 +7118,9 @@ do_ident (buf, limit, op, keyword)
static int
do_pragma (buf, limit, op, keyword)
U_CHAR *buf, *limit ATTRIBUTE_UNUSED;
FILE_BUF *op ATTRIBUTE_UNUSED;
struct directive *keyword ATTRIBUTE_UNUSED;
U_CHAR *buf, *limit;
FILE_BUF *op;
struct directive *keyword;
{
SKIP_WHITE_SPACE (buf);
if (!strncmp ((char *) buf, "once", 4)) {
@ -7100,6 +7131,29 @@ do_pragma (buf, limit, op, keyword)
do_once ();
}
if (!strncmp (buf, "poison", 6)) {
/* Poison these symbols so that all subsequent usage produces an
error message. */
U_CHAR *p = buf + 6;
SKIP_WHITE_SPACE (p);
while (p < limit)
{
U_CHAR *end = p;
while (end < limit && is_idchar[*end])
end++;
if (end < limit && !is_space[*end])
{
error ("invalid #pragma poison");
return 0;
}
do_define(p, end, op, keyword);
p = end;
SKIP_WHITE_SPACE (p);
}
}
if (!strncmp ((char *) buf, "implementation", 14)) {
/* Be quiet about `#pragma implementation' for a file only if it hasn't
been included yet. */
@ -7351,6 +7405,10 @@ do_xifdef (buf, limit, op, keyword)
}
}
if ((hp != NULL) && (hp->type == T_POISON)) {
error("attempt to use poisoned `%s'.", hp->name);
hp = NULL;
}
skip = (hp == NULL) ^ (keyword->type == T_IFNDEF);
if (start_of_file && !skip) {
control_macro = (U_CHAR *) xmalloc (end - buf + 1);

26
gcc/cpp.texi
View File

@ -551,6 +551,7 @@ in the C preprocessor.
* Concatenation:: Building tokens from parts taken from macro arguments.
* Undefining:: Cancelling a macro's definition.
* Redefining:: Changing a macro's definition.
* Poisoning:: Ensuring a macro is never defined or used.
* Macro Pitfalls:: Macros can confuse the unwary. Here we explain
several common problems and strange features.
@end menu
@ -1370,7 +1371,7 @@ The same form of @samp{#undef} directive will cancel definitions with
arguments or definitions that don't expect arguments. The @samp{#undef}
directive has no effect when used on a name not currently defined as a macro.
@node Redefining, Macro Pitfalls, Undefining, Macros
@node Redefining, Poisoning, Undefining, Macros
@subsection Redefining Macros
@cindex redefining macros
@ -1404,7 +1405,28 @@ where there was no whitespace at all.
Recall that a comment counts as whitespace.
@node Macro Pitfalls,, Redefining, Macros
@node Poisoning, Macro Pitfalls, Redefining, Macros
@subsection Poisoning Macros
@cindex poisoning macros
Sometimes, there is an identifier that you want to remove completely
from your program, and make sure that it never creeps back in. To
enforce this, the @samp{#pragma poison} directive can be used.
@samp{#pragma poison} is followed by a list of identifiers to poison,
and takes effect for the rest of the source. You cannot @samp{#undef} a
poisoned identifier or test to see if it's defined with @samp{#ifdef}.
For example,
@example
#pragma poison printf sprintf fprintf
sprintf(some_string, "hello");
@end example
@noindent
will produce an error.
@node Macro Pitfalls,, Poisoning, Macros
@subsection Pitfalls and Subtleties of Macros
@cindex problems with macros
@cindex pitfalls of macros

11
gcc/cppexp.c
View File

@ -27,6 +27,7 @@ Written by Per Bothner 1994. */
#include "config.h"
#include "system.h"
#include "cpplib.h"
#include "cpphash.h"
#ifdef MULTIBYTE_CHARS
#include <locale.h>
@ -445,6 +446,7 @@ cpp_lex (pfile, skip_evaluation)
int paren = 0, len;
cpp_buffer *ip = CPP_BUFFER (pfile);
U_CHAR *tok;
HASHNODE *hp;
cpp_skip_hspace (pfile);
if (*ip->cur == '(')
@ -469,9 +471,14 @@ cpp_lex (pfile, skip_evaluation)
goto oops;
++ip->cur;
}
if (cpp_lookup (pfile, tok, len, -1))
hp = cpp_lookup (pfile, tok, len, -1);
if (hp != NULL)
{
if (hp->type == T_POISON)
cpp_error (pfile, "attempt to use poisoned `%s'", hp->name);
else
op.value = 1;
}
}
return op;

7
gcc/cpphash.c
View File

@ -1020,6 +1020,13 @@ special_symbol (hp, pfile)
return;
}
case T_POISON:
cpp_error (pfile, "attempt to use poisoned `%s'.", hp->name);
CPP_RESERVE (pfile, 1);
CPP_PUTC_Q (pfile, '0');
CPP_NUL_TERMINATE_Q (pfile);
break;
default:
cpp_fatal (pfile, "cpplib internal error: invalid special hash type");
return;

100
gcc/cpplib.c
View File

@ -625,8 +625,9 @@ check_macro_name (pfile, symname, assertion)
}
/* Process a #define command.
KEYWORD is the keyword-table entry for #define,
or NULL for a "predefined" macro. */
KEYWORD is the keyword-table entry for #define,
or NULL for a "predefined" macro,
or the keyword-table entry for #pragma in the case of a #pragma poison. */
static int
do_define (pfile, keyword)
@ -638,10 +639,16 @@ do_define (pfile, keyword)
HASHNODE *hp;
long here;
U_CHAR *macro, *buf, *end;
enum node_type new_type;
here = CPP_WRITTEN (pfile);
copy_rest_of_line (pfile);
if (keyword == NULL || keyword->type == T_DEFINE)
new_type = T_MACRO;
else
new_type = T_POISON;
/* Copy out the line so we can pop the token buffer. */
buf = pfile->token_buffer + here;
end = CPP_PWRITTEN (pfile);
@ -663,30 +670,40 @@ do_define (pfile, keyword)
/* Redefining a precompiled key is ok. */
if (hp->type == T_PCSTRING)
ok = 1;
/* Redefining a poisoned identifier is even worse than `not ok'. */
else if (hp->type == T_POISON)
ok = -1;
/* Redefining a macro is ok if the definitions are the same. */
else if (hp->type == T_MACRO)
ok = ! compare_defs (pfile, mdef.defn, hp->value.defn);
/* Redefining a constant is ok with -D. */
else if (hp->type == T_CONST || hp->type == T_STDC)
ok = ! CPP_OPTIONS (pfile)->done_initializing;
/* Print the warning if it's not ok. */
if (!ok)
/* Print the warning or error if it's not ok. */
if (ok <= 0)
{
if (hp->type == T_POISON)
cpp_error (pfile, "redefining poisoned `%.*s'",
mdef.symlen, mdef.symnam);
else
cpp_pedwarn (pfile, "`%.*s' redefined", mdef.symlen, mdef.symnam);
if (hp->type == T_MACRO)
cpp_pedwarn_with_file_and_line (pfile, hp->value.defn->file,
hp->value.defn->line,
"this is the location of the previous definition");
}
if (hp->type != T_POISON)
{
/* Replace the old definition. */
hp->type = T_MACRO;
hp->type = new_type;
hp->value.defn = mdef.defn;
}
}
else
cpp_install (pfile, mdef.symnam, mdef.symlen, T_MACRO,
cpp_install (pfile, mdef.symnam, mdef.symlen, new_type,
(char *) mdef.defn, hashcode);
if (keyword)
if (keyword != NULL && keyword->type == T_DEFINE)
{
if (CPP_OPTIONS (pfile)->debug_output
|| CPP_OPTIONS (pfile)->dump_macros == dump_definitions)
@ -1425,10 +1442,15 @@ do_undef (pfile, keyword)
need to pass through all effective #undef commands. */
if (CPP_OPTIONS (pfile)->debug_output && keyword)
pass_thru_directive (name, sym_length, pfile, keyword);
if (hp->type == T_POISON)
cpp_error (pfile, "cannot undefine poisoned `%s'", hp->name);
else
{
if (hp->type != T_MACRO)
cpp_warning (pfile, "undefining `%s'", hp->name);
delete_macro (hp);
}
}
return 0;
}
@ -1579,6 +1601,65 @@ do_pragma (pfile, keyword)
"`#pragma implementation' for `%s' appears after file is included",
fcopy);
}
else if (!strncmp (buf, "poison", 6))
{
/* Poison these symbols so that all subsequent usage produces an
error message. */
U_CHAR *p = buf + 6;
size_t plen;
U_CHAR *syms;
int writeit;
SKIP_WHITE_SPACE (p);
plen = strlen(p) + 1;
syms = (U_CHAR *) alloca (plen);
memcpy (syms, p, plen);
/* As a rule, don't include #pragma poison commands in output,
unless the user asks for them. */
writeit = (CPP_OPTIONS (pfile)->debug_output
|| CPP_OPTIONS (pfile)->dump_macros == dump_definitions
|| CPP_OPTIONS (pfile)->dump_macros == dump_names);
if (writeit)
CPP_SET_WRITTEN (pfile, here);
else
CPP_SET_WRITTEN (pfile, here-8);
if (writeit)
{
CPP_RESERVE (pfile, plen + 7);
CPP_PUTS_Q (pfile, "poison", 7);
}
while (*syms != '\0')
{
U_CHAR *end = syms;
while (is_idchar[*end])
end++;
if (!is_hor_space[*end] && *end != '\0')
{
cpp_error (pfile, "invalid #pragma poison directive");
return 1;
}
if (cpp_push_buffer (pfile, syms, end - syms) != NULL)
{
do_define (pfile, keyword);
cpp_pop_buffer (pfile);
}
if (writeit)
{
CPP_PUTC_Q (pfile, ' ');
CPP_PUTS_Q (pfile, syms, end - syms);
}
syms = end;
SKIP_WHITE_SPACE (syms);
}
}
return 0;
}
@ -1807,6 +1888,11 @@ do_xifdef (pfile, keyword)
control_macro = (U_CHAR *) xmalloc (ident_length + 1);
bcopy (ident, control_macro, ident_length + 1);
}
if (hp != NULL && hp->type == T_POISON)
{
cpp_error (pfile, "attempt to use poisoned `%s'", hp->name);
skip = !skip;
}
}
else
{

1
gcc/cpplib.h
View File

@ -600,6 +600,7 @@ enum node_type {
T_MACRO, /* macro defined by `#define' */
T_DISABLED, /* macro temporarily turned off for rescan */
T_PCSTRING, /* precompiled string (hashval is KEYDEF *) */
T_POISON, /* defined with `#pragma poison' */
T_UNUSED /* Used for something not defined. */
};

5
gcc/testsuite/gcc.c-torture/ChangeLog
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@ -1,3 +1,8 @@
1999-09-08 Geoffrey Keating <geoffk@cygnus.com>
* noncompile/noncompile.exp: Add poison-1.c.
* noncompile/poison-1.c: New file.
1999-09-06 Franz Sirl <Franz.Sirl-kernel@lauterbach.com>
* execute/va-arg-9.c: New test.

10
gcc/testsuite/gcc.c-torture/noncompile/noncompile.exp
View File

@ -323,3 +323,13 @@ set compiler_output ".*:6:"
set groups {passed gcc-noncompile}
postbase_with_opts $src_code $run $groups
# Test poison-1.c
prebase
set src_code poison-1.c
set compiler_output ".*c:2:.*c:4:.*c:5:.*c:7:.*c:8:.*c:9:.*c:11:.*c:12:.*c:13:.*c:14:.*c:17:.*c:20:"
set groups {passed gcc-noncompile}
postbase $src_code $run $groups

22
gcc/testsuite/gcc.c-torture/noncompile/poison-1.c Normal file
View File

@ -0,0 +1,22 @@
#pragma poison foo
foo
#pragma poison foo2 foo3
foo2
foo3
#pragma poison foo4 foo5
foo4
foo5
#pragma poison +++
#define foo6 123
#pragma poison foo6
#define foo6 345
#define foo6 456
#ifdef foo6
#error hey! foo6 poisoned!
#endif
#if defined(foo6)
#error no, foo6 still poisoned!
#else
foo6
#endif
#pragma poison