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* [Bug c++/47634] New: Incorrect checking of attribute format printf on constructor of derived class with virtual base
@ 2011-02-07 14:50 dan at randomdan dot homeip.net
2021-08-09 18:26 ` [Bug c++/47634] " pinskia at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: dan at randomdan dot homeip.net @ 2011-02-07 14:50 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47634
Summary: Incorrect checking of attribute format printf on
constructor of derived class with virtual base
Product: gcc
Version: 4.4.5
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: dan@randomdan.homeip.net
Given the below code, gcc produces the following warnings:
exception.cpp: In function 'int main(int, char**)':
exception.cpp:28: warning: format not a string literal and no format arguments
Changing the __attribute__ on VDerived's constructor to be the same as Derived
produces the following error:
exception.cpp:9: error: format string argument not a string type
Compiled simply with:
g++ exception.cpp
class Base {
public:
Base() {
}
};
class VDerived : public virtual Base {
public:
VDerived(int x, const char * f, ...) __attribute__((format(printf, 5,
6)));
};
class Derived : public Base {
public:
Derived(int x, const char * f, ...) __attribute__((format(printf, 3,
4)));
};
VDerived::VDerived(int x, const char * f, ...)
{
}
Derived::Derived(int x, const char * f, ...)
{
}
int
main(int, char **)
{
throw VDerived(1, "%s %d", "foo", 1);
throw Derived(1, "%s %d", "bar", 1);
}
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/47634] Incorrect checking of attribute format printf on constructor of derived class with virtual base
2011-02-07 14:50 [Bug c++/47634] New: Incorrect checking of attribute format printf on constructor of derived class with virtual base dan at randomdan dot homeip.net
@ 2021-08-09 18:26 ` pinskia at gcc dot gnu.org
2022-03-31 22:37 ` mpolacek at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-09 18:26 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47634
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=101833
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I have not exactly looked into this bug but I did find an ICE dealing with the
code: PR 101833.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/47634] Incorrect checking of attribute format printf on constructor of derived class with virtual base
2011-02-07 14:50 [Bug c++/47634] New: Incorrect checking of attribute format printf on constructor of derived class with virtual base dan at randomdan dot homeip.net
2021-08-09 18:26 ` [Bug c++/47634] " pinskia at gcc dot gnu.org
@ 2022-03-31 22:37 ` mpolacek at gcc dot gnu.org
2022-05-07 14:44 ` cvs-commit at gcc dot gnu.org
2022-05-07 14:59 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2022-03-31 22:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47634
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |mpolacek at gcc dot gnu.org
Ever confirmed|0 |1
Assignee|unassigned at gcc dot gnu.org |mpolacek at gcc dot gnu.org
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2022-03-31
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/47634] Incorrect checking of attribute format printf on constructor of derived class with virtual base
2011-02-07 14:50 [Bug c++/47634] New: Incorrect checking of attribute format printf on constructor of derived class with virtual base dan at randomdan dot homeip.net
2021-08-09 18:26 ` [Bug c++/47634] " pinskia at gcc dot gnu.org
2022-03-31 22:37 ` mpolacek at gcc dot gnu.org
@ 2022-05-07 14:44 ` cvs-commit at gcc dot gnu.org
2022-05-07 14:59 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-05-07 14:44 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47634
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:
https://gcc.gnu.org/g:0c723bb4be2a67657828b692997855afcdc5d286
commit r13-167-g0c723bb4be2a67657828b692997855afcdc5d286
Author: Marek Polacek <polacek@redhat.com>
Date: Thu Mar 31 18:31:39 2022 -0400
c, c++: attribute format on a ctor with a vbase [PR101833, PR47634]
Attribute format takes three arguments: archetype, string-index, and
first-to-check. The last two specify the position in the function
parameter list. r63030 clarified that "Since non-static C++ methods have
an implicit this argument, the arguments of such methods should be counted
from two, not one, when giving values for string-index and first-to-check."
Therefore one has to write
struct D {
D(const char *, ...) __attribute__((format(printf, 2, 3)));
};
However -- and this is the problem in this PR -- ctors with virtual
bases also get two additional parameters: the in-charge parameter and
the VTT parameter (added in maybe_retrofit_in_chrg). In fact we'll end up
with two clones of the ctor: an in-charge and a not-in-charge version (see
build_cdtor_clones). That means that the argument position the user
specified in the attribute argument will refer to different arguments,
depending on which constructor we're currently dealing with. This can
cause a range of problems: wrong errors, confusing warnings, or crashes.
This patch corrects that; for C we don't have to do anything, and in C++
we can use num_artificial_parms_for. It would be wrong to rewrite the
attributes the user supplied, so I've changed POS to be passed by
reference so that we don't have to change all the call sites of
positional_argument and we still get the default_conversion adjustment.
Attribute format_arg is not affected, because it requires that the
function returns "const char *" which will never be the case for cdtors.
PR c++/101833
PR c++/47634
gcc/c-family/ChangeLog:
* c-attribs.cc (positional_argument): Pass POS by reference. Deal
with FN being either a function declaration or function type. Use
maybe_adjust_arg_pos_for_attribute.
* c-common.cc (check_function_arguments): Maybe pass FNDECL down to
check_function_format.
* c-common.h (maybe_adjust_arg_pos_for_attribute): Declare.
(positional_argument): Adjust.
* c-format.cc (get_constant): Rename to ...
(validate_constant): ... this. Take EXPR by reference. Return
bool
instead of tree.
(handle_format_arg_attribute): Don't overwrite FORMAT_NUM_EXPR by
the
return value of validate_constant.
(decode_format_attr): Don't overwrite FORMAT_NUM_EXPR and
FIRST_ARG_NUM_EXPR by the return value of validate_constant.
(check_function_format): Adjust a parameter name.
(handle_format_attribute): Maybe pass FNDECL down to
decode_format_attr.
gcc/c/ChangeLog:
* c-objc-common.cc (maybe_adjust_arg_pos_for_attribute): New.
gcc/cp/ChangeLog:
* tree.cc (maybe_adjust_arg_pos_for_attribute): New.
gcc/ChangeLog:
* tree-core.h (struct attribute_spec): Update comment for HANDLER.
gcc/testsuite/ChangeLog:
* g++.dg/ext/attr-format-arg1.C: New test.
* g++.dg/ext/attr-format1.C: New test.
* g++.dg/ext/attr-format2.C: New test.
* g++.dg/ext/attr-format3.C: New test.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/47634] Incorrect checking of attribute format printf on constructor of derived class with virtual base
2011-02-07 14:50 [Bug c++/47634] New: Incorrect checking of attribute format printf on constructor of derived class with virtual base dan at randomdan dot homeip.net
` (2 preceding siblings ...)
2022-05-07 14:44 ` cvs-commit at gcc dot gnu.org
@ 2022-05-07 14:59 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2022-05-07 14:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47634
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|ASSIGNED |RESOLVED
--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed for GCC 13.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2011-02-07 14:50 [Bug c++/47634] New: Incorrect checking of attribute format printf on constructor of derived class with virtual base dan at randomdan dot homeip.net
2021-08-09 18:26 ` [Bug c++/47634] " pinskia at gcc dot gnu.org
2022-03-31 22:37 ` mpolacek at gcc dot gnu.org
2022-05-07 14:44 ` cvs-commit at gcc dot gnu.org
2022-05-07 14:59 ` mpolacek at gcc dot gnu.org
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