( https://gcc.gnu.org/ml/gcc-patches/2014-06/msg01692.html )
On Sun, 22 Jun 2014, Marc Glisse wrote:
Hello,
I followed the advice in this discussion:
https://gcc.gnu.org/ml/gcc-patches/2014-04/msg00269.html
and here is a new patch. I made an effort to isolate a path in at least one
subcase so it doesn't look too strange that the warning is in this file.
Computing the dominance info just to tweak the warning message may be a bit
excessive. I kept the same option as the front-ends, I don't know if we want
a different one, or maybe a Wmaybe-... version. There will be cases where we
get a duplicate warning from -Wtarget-lifetime in fortran, but none in the
testsuite, and I would rather have 2 warnings than miss such broken code. The
uninit-G testcase is about initialization, not returning, so I am changing
that, even if it is unnecessary with the current version of the patch (only
activated at -O2).
Bootstrap+testsuite (--enable-languages=all,obj-c++,ada,go) on
x86_64-unknown-linux-gnu.
(by the way, contrib/compare_tests is confused when I use all languages, it
prints "comm: file 1 is not in sorted order" and tons of spurious
differences)
2014-06-23 Marc Glisse <marc.gli...@inria.fr>
PR c++/60517
gcc/c/
* c-typeck.c (c_finish_return): Return 0 instead of the address of
a local variable.
gcc/cp/
* typeck.c (maybe_warn_about_returning_address_of_local): Return
whether it is returning the address of a local variable.
(check_return_expr): Return 0 instead of the address of a local
variable.
gcc/c-family/
* c.opt (-Wreturn-local-addr): Move to common.opt.
gcc/
* common.opt (-Wreturn-local-addr): Moved from c.opt.
* gimple-ssa-isolate-paths.c: Include diagnostic-core.h.
(isolate_path): New argument to avoid inserting a trap.
(find_implicit_erroneous_behaviour): Handle returning the address
of a local variable.
(find_explicit_erroneous_behaviour): Likewise.
(gimple_ssa_isolate_erroneous_paths): Calculate dominance info.
gcc/testsuite/
* c-c++-common/addrtmp.c: New file.
* c-c++-common/uninit-G.c: Adapt.
After looking at PR 61597, I updated the 2 conditions to:
+ if ((TREE_CODE (valbase) == VAR_DECL
+ && !is_global_var (valbase))
+ || TREE_CODE (valbase) == PARM_DECL)
a PARM_DECL is a local variable and returning its address is wrong, isn't
it?
(also passes bootstrap+testsuite)
--
Marc Glisse
