Ping - can I get this reviewed before stage 1 ends?
On 21 October 2012 22:25, Dodji Seketeli <do...@seketeli.org> wrote:
> The C++ bits look good to my casual non-maintainer eyes. Let's CC
> Jason.
>
> Thanks.
>
> Jonathan Wakely <jwakely....@gmail.com> a écrit:
>
>> This adds a warning switch for the existing "returning address of
>> local variable" warnings in the C and C++ FEs which are enabled by
>> default but have no switch controlling them. Adding a switch allows it
>> to be turned into an error with -Werror=return-local-addr. I've added
>> two tests checking the -Werror form works.
>>
>> gcc/c-family:
>> PR c++/54930
>> * c.opt (Wreturn_local_addr): Define new option.
>>
>> gcc/c:
>> PR c++/54930
>> * c-typeck.c (c_finish_return): Use OPT_Wreturn_local_addr.
>>
>> gcc/cp:
>> PR c++/54930
>> * typeck.c (maybe_warn_about_returning_address_of_local): Use
>> OPT_Wreturn_local_addr.
>>
>> gcc:
>> PR c++/54930
>> * doc/invoke.texi (Warning Options): Document -Wno-return-local-addr.
>>
>> gcc/testsuite:
>> PR c++/54930
>> * gcc.dg/Wreturn-local-addr.c: New.
>> * g++.dg/warn/Wno-return-local-addr.C: New.
>> * g++.dg/warn/Wreturn-local-addr.C: New.
>>
>> Tested x86_64-linux, OK for trunk?
>>
>> commit 77abe727e837e052680be8020fa2990cce4d1e9a
>> Author: Jonathan Wakely <jwakely....@gmail.com>
>> Date: Wed Oct 17 19:32:10 2012 +0100
>>
>> gcc/c-family:
>> PR c++/54930
>> * c.opt (Wreturn_local_addr): Define new option.
>>
>> gcc/c:
>> PR c++/54930
>> * c-typeck.c (c_finish_return): Use OPT_Wreturn_local_addr.
>>
>> gcc/cp:
>> PR c++/54930
>> * typeck.c (maybe_warn_about_returning_address_of_local): Use
>> OPT_Wreturn_local_addr.
>>
>> gcc:
>> PR c++/54930
>> * doc/invoke.texi (Warning Options): Document -Wno-return-local-addr.
>>
>> gcc/testsuite:
>> PR c++/54930
>> * gcc.dg/Wreturn-local-addr.c: New.
>> * g++.dg/warn/Wno-return-local-addr.C: New.
>> * g++.dg/warn/Wreturn-local-addr.C: New.
>>
>> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
>> index 3166984..f75b58c 100644
>> --- a/gcc/c-family/c.opt
>> +++ b/gcc/c-family/c.opt
>> @@ -601,6 +601,10 @@ Wreorder
>> C++ ObjC++ Var(warn_reorder) Warning LangEnabledBy(C++ ObjC++,Wall)
>> Warn when the compiler reorders code
>>
>> +Wreturn-local-addr
>> +C ObjC C++ ObjC++ Var(warn_return_local_addr) Init(1) Warning
>> +Warn about returning a pointer/reference to a local or temporary variable.
>> +
>> Wreturn-type
>> C ObjC C++ ObjC++ Var(warn_return_type) Warning
>> Warn whenever a function's return type defaults to \"int\" (C), or about
>> inconsistent return types (C++)
>> diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
>> index 4855933..cf63355 100644
>> --- a/gcc/c/c-typeck.c
>> +++ b/gcc/c/c-typeck.c
>> @@ -8742,7 +8742,8 @@ c_finish_return (location_t loc, tree retval, tree
>> origtype)
>> && !TREE_STATIC (inner)
>> && DECL_CONTEXT (inner) == current_function_decl)
>> warning_at (loc,
>> - 0, "function returns address of local variable");
>> + OPT_Wreturn_local_addr, "function returns address "
>> + "of local variable");
>> break;
>>
>> default:
>> diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
>> index eaa0935..d2944d3 100644
>> --- a/gcc/cp/typeck.c
>> +++ b/gcc/cp/typeck.c
>> @@ -8019,14 +8019,14 @@ maybe_warn_about_returning_address_of_local (tree
>> retval)
>> if (TREE_CODE (whats_returned) == AGGR_INIT_EXPR
>> || TREE_CODE (whats_returned) == TARGET_EXPR)
>> {
>> - warning (0, "returning reference to temporary");
>> + warning (OPT_Wreturn_local_addr, "returning reference to temporary");
>> return;
>> }
>> if (TREE_CODE (whats_returned) == VAR_DECL
>> && DECL_NAME (whats_returned)
>> && TEMP_NAME_P (DECL_NAME (whats_returned)))
>> {
>> - warning (0, "reference to non-lvalue returned");
>> + warning (OPT_Wreturn_local_addr, "reference to non-lvalue returned");
>> return;
>> }
>> }
>> @@ -8042,10 +8042,10 @@ maybe_warn_about_returning_address_of_local (tree
>> retval)
>> || TREE_PUBLIC (whats_returned)))
>> {
>> if (TREE_CODE (valtype) == REFERENCE_TYPE)
>> - warning (0, "reference to local variable %q+D returned",
>> + warning (OPT_Wreturn_local_addr, "reference to local variable %q+D
>> returned",
>> whats_returned);
>> else
>> - warning (0, "address of local variable %q+D returned",
>> + warning (OPT_Wreturn_local_addr, "address of local variable %q+D
>> returned",
>> whats_returned);
>> return;
>> }
>> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
>> index f8c9230..2e36de1 100644
>> --- a/gcc/doc/invoke.texi
>> +++ b/gcc/doc/invoke.texi
>> @@ -261,7 +261,7 @@ Objective-C and Objective-C++ Dialects}.
>> -Woverlength-strings -Wpacked -Wpacked-bitfield-compat -Wpadded @gol
>> -Wparentheses -Wpedantic-ms-format -Wno-pedantic-ms-format @gol
>> -Wpointer-arith -Wno-pointer-to-int-cast @gol
>> --Wredundant-decls @gol
>> +-Wredundant-decls -Wno-return-local-addr @gol
>> -Wreturn-type -Wsequence-point -Wshadow @gol
>> -Wsign-compare -Wsign-conversion -Wsizeof-pointer-memaccess @gol
>> -Wstack-protector -Wstack-usage=@var{len} -Wstrict-aliasing @gol
>> @@ -3526,6 +3526,12 @@ definitions, may be found on the GCC readings page, at
>>
>> This warning is enabled by @option{-Wall} for C and C++.
>>
>> +@item -Wno-return-local-addr
>> +@opindex Wno-return-local-addr
>> +@opindex Wreturn-local-addr
>> +Do not warn about returning a pointer (or in C++, a reference) to a
>> +variable that goes out of scope after the function returns.
>> +
>> @item -Wreturn-type
>> @opindex Wreturn-type
>> @opindex Wno-return-type
>> diff --git a/gcc/testsuite/g++.dg/warn/Wno-return-local-addr.C
>> b/gcc/testsuite/g++.dg/warn/Wno-return-local-addr.C
>> new file mode 100644
>> index 0000000..e15bfa2
>> --- /dev/null
>> +++ b/gcc/testsuite/g++.dg/warn/Wno-return-local-addr.C
>> @@ -0,0 +1,26 @@
>> +// { dg-do assemble }
>> +// { dg-options "-Wno-return-local-addr" }
>> +
>> +int& bad1()
>> +{
>> + int x = 0;
>> + return x;
>> +}
>> +
>> +int* bad2()
>> +{
>> + int x = 0;
>> + return &x;
>> +}
>> +
>> +int f();
>> +
>> +const int& bad3()
>> +{
>> + return f();
>> +}
>> +
>> +const int& bad4()
>> +{
>> + return int();
>> +}
>> diff --git a/gcc/testsuite/g++.dg/warn/Wreturn-local-addr.C
>> b/gcc/testsuite/g++.dg/warn/Wreturn-local-addr.C
>> new file mode 100644
>> index 0000000..faa3a34
>> --- /dev/null
>> +++ b/gcc/testsuite/g++.dg/warn/Wreturn-local-addr.C
>> @@ -0,0 +1,20 @@
>> +// { dg-do assemble }
>> +// { dg-options "-Werror=return-local-addr" }
>> +// { dg-message "some warnings being treated as errors" "" {target "*-*-*"}
>> 0 }
>> +
>> +int& bad1()
>> +{
>> + int x = 0; // { dg-error "reference to local variable" }
>> + return x;
>> +}
>> +
>> +int* bad2()
>> +{
>> + int x = 0; // { dg-error "address of local variable" }
>> + return &x;
>> +}
>> +
>> +const int& bad4()
>> +{
>> + return int(); // { dg-error "returning reference to
>> temporary" }
>> +}
>> diff --git a/gcc/testsuite/gcc.dg/Wreturn-local-addr.c
>> b/gcc/testsuite/gcc.dg/Wreturn-local-addr.c
>> new file mode 100644
>> index 0000000..d496d20
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.dg/Wreturn-local-addr.c
>> @@ -0,0 +1,9 @@
>> +/* { dg-do assemble } */
>> +/* { dg-options "-Werror=return-local-addr" } */
>> +/* { dg-message "some warnings being treated as errors" "" {target "*-*-*"}
>> 0 } */
>> +
>> +int* bad()
>> +{
>> + int x = 0;
>> + return &x; /* { dg-error "address of local variable" } */
>> +}
>
> --
> Dodji
