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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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 \

17
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;
@ -338,9 +342,11 @@ handle_pragma_token (string, token)
#ifdef HANDLE_PRAGMA_WEAK
if (strcmp (string, "weak") == 0)
type = state = ps_weak;
#endif
#endif
if (strcmp (string, "poison") == 0)
type = state = ps_poison;
break;
#ifdef HANDLE_PRAGMA_WEAK
case ps_weak:
name = permalloc (strlen (string) + 1);
@ -485,7 +491,12 @@ handle_pragma_token (string, token)
state = ps_bad;
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
};

108
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. */
};
@ -4281,7 +4282,12 @@ 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);
buf = " 1 ";
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) {
@ -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)
@ -5944,35 +5956,50 @@ 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) {
/* 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);
pedwarn ("`%.*s' redefined", mdef.symlen, mdef.symnam);
if (hp->type == T_MACRO)
pedwarn_with_file_and_line (hp->value.defn->file,
hp->value.defn->file_len,
hp->value.defn->line,
"this is the location of the previous definition");
}
/* Replace the old definition. */
hp->type = T_MACRO;
hp->value.defn = mdef.defn;
/* 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,
hp->value.defn->file_len,
hp->value.defn->line,
"this is the location of the previous definition");
}
if (hp->type != T_POISON)
{
/* Replace the old definition. */
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);
}
}
@ -6990,9 +7017,13 @@ 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_MACRO)
warning ("undefining `%s'", hp->name);
delete_macro (hp);
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) {
@ -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

13
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))
op.value = 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;

112
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)
{
cpp_pedwarn (pfile, "`%.*s' redefined", mdef.symlen, mdef.symnam);
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");
}
/* Replace the old definition. */
hp->type = T_MACRO;
hp->value.defn = mdef.defn;
if (hp->type != T_POISON)
{
/* Replace the old definition. */
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)
@ -1425,9 +1442,14 @@ 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_MACRO)
cpp_warning (pfile, "undefining `%s'", hp->name);
delete_macro (hp);
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
View File

@ -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