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Re: PING^4 Re: [PATCH] Add -fno-instrument-function v2


Andi Kleen <andi@firstfloor.org> writes:

PING^4 if it isn't already too late for 4.9.

> Andi Kleen <andi@firstfloor.org> writes:
>
>
> PING^3
>
> Since it doesn't look like a generic solution for the
> LTO options problem will appear this development cycle,
> I would still like to pursue this option for 4.9.
> This would help fixing parts of the linux kernel LTO
> build.
>
> Can someone please review the patch?
>
> Thanks
>
>> Andi Kleen <andi@firstfloor.org> writes:
>>
>> PING^2
>>
>>> Andi Kleen <andi@firstfloor.org> writes:
>>>
>>>> From: Andi Kleen <ak@linux.intel.com>
>>>>
>>>> [I posted this originally quite some time ago.
>>>> This version fixes all review problems, particularly
>>>> it works for C++ too and the test case really works.]
>>>
>>> Ping!
>>>
>>> Could someone please review it.
>>>
>>> Note this might be obsolete with Honza's LTO option work, but if it's
>>> not covered in his first iteration I would still have it earlier for the
>>> Linux kernel LTO build (fixed ftrace)
>>>
>>> -Andi
>>>
>>>> This adds a new C/C++ option to force
>>>> __attribute__((no_instrument_function)) on every function compiled.
>>>>
>>>> This is useful together with LTO. You may want to have the whole
>>>> program compiled with -pg and have to specify that in the LTO
>>>> link, but want to disable it for some specific files. As the
>>>> option works on the frontend level it is already passed through
>>>> properly by LTO.
>>>>
>>>> Without LTO it is equivalent to not specifing -pg or -mfentry.
>>>>
>>>> This fixes some missing functionality in the Linux kernel LTO port.
>>>>
>>>> Passed bootstrap and test suite on x86_64-linux. Ok?
>>>>
>>>> gcc/:
>>>>
>>>> 2013-08-10  Andi Kleen <ak@linux.intel.com>
>>>>
>>>> 	* c.opt (fno-instrument-function): Document.
>>>>
>>>> gcc/c:
>>>>
>>>> 2013-08-10  Andi Kleen <ak@linux.intel.com>
>>>>
>>>> 	* c-decl.c (start_function): Handle force_no_instrument_function
>>>>
>>>> gcc/cp:
>>>>
>>>> 2013-08-10  Andi Kleen <ak@linux.intel.com>
>>>>
>>>> 	* decl.c (start_preparsed_function): Handle
>>>>   	force_no_instrument_function
>>>>
>>>> gcc/testsuite:
>>>>
>>>> 2013-08-10  Andi Kleen <ak@linux.intel.com>
>>>>
>>>> 	* g++.dg/fno-instrument-function.C: Add.
>>>> 	* gcc.dg/fno-instrument-function.c: Add.
>>>> ---
>>>>  gcc/c-family/c.opt                             |  4 ++++
>>>>  gcc/c/c-decl.c                                 |  3 +++
>>>>  gcc/cp/decl.c                                  |  3 +++
>>>>  gcc/doc/invoke.texi                            |  8 +++++++-
>>>>  gcc/testsuite/g++.dg/fno-instrument-function.C | 18 ++++++++++++++++++
>>>>  gcc/testsuite/gcc.dg/fno-instrument-function.c | 24 ++++++++++++++++++++++++
>>>>  6 files changed, 59 insertions(+), 1 deletion(-)
>>>>  create mode 100644 gcc/testsuite/g++.dg/fno-instrument-function.C
>>>>  create mode 100644 gcc/testsuite/gcc.dg/fno-instrument-function.c
>>>>
>>>> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
>>>> index 10ae84d..2159f89 100644
>>>> --- a/gcc/c-family/c.opt
>>>> +++ b/gcc/c-family/c.opt
>>>> @@ -1014,6 +1014,10 @@ fnil-receivers
>>>>  ObjC ObjC++ Var(flag_nil_receivers) Init(1)
>>>>  Assume that receivers of Objective-C messages may be nil
>>>>  
>>>> +fno-instrument-function
>>>> +C C++ ObjC ObjC++ RejectNegative Report Var(force_no_instrument_function)
>>>> +Force __attribute__((no_instrument_function)) for all functions in translation unit.
>>>> +
>>>>  fnonansi-builtins
>>>>  C++ ObjC++ Var(flag_no_nonansi_builtin, 0)
>>>>  
>>>> diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
>>>> index d9bbf5c..15717a9 100644
>>>> --- a/gcc/c/c-decl.c
>>>> +++ b/gcc/c/c-decl.c
>>>> @@ -7876,6 +7876,9 @@ start_function (struct c_declspecs *declspecs, struct c_declarator *declarator,
>>>>    if (current_scope == file_scope)
>>>>      maybe_apply_pragma_weak (decl1);
>>>>  
>>>> +  if (force_no_instrument_function)
>>>> +    DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl1) = 1;  
>>>> +
>>>>    /* Warn for unlikely, improbable, or stupid declarations of `main'.  */
>>>>    if (warn_main && MAIN_NAME_P (DECL_NAME (decl1)))
>>>>      {
>>>> diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
>>>> index 01804d2..103188b 100644
>>>> --- a/gcc/cp/decl.c
>>>> +++ b/gcc/cp/decl.c
>>>> @@ -13023,6 +13023,9 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
>>>>        && lookup_attribute ("noinline", attrs))
>>>>      warning (0, "inline function %q+D given attribute noinline", decl1);
>>>>  
>>>> +  if (force_no_instrument_function)
>>>> +    DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl1) = 1;
>>>> +
>>>>    /* Handle gnu_inline attribute.  */
>>>>    if (GNU_INLINE_P (decl1))
>>>>      {
>>>> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
>>>> index 782b569..bc20a77 100644
>>>> --- a/gcc/doc/invoke.texi
>>>> +++ b/gcc/doc/invoke.texi
>>>> @@ -169,7 +169,7 @@ in the following sections.
>>>>  -aux-info @var{filename} -fallow-parameterless-variadic-functions @gol
>>>>  -fno-asm  -fno-builtin  -fno-builtin-@var{function} @gol
>>>>  -fhosted  -ffreestanding -fopenmp -fms-extensions -fplan9-extensions @gol
>>>> --trigraphs  -traditional  -traditional-cpp @gol
>>>> +-trigraphs  -traditional  -traditional-cpp -fno-instrument-function @gol
>>>>  -fallow-single-precision  -fcond-mismatch -flax-vector-conversions @gol
>>>>  -fsigned-bitfields  -fsigned-char @gol
>>>>  -funsigned-bitfields  -funsigned-char}
>>>> @@ -1868,6 +1868,12 @@ Allow implicit conversions between vectors with differing numbers of
>>>>  elements and/or incompatible element types.  This option should not be
>>>>  used for new code.
>>>>  
>>>> +@item -fno-instrument-function
>>>> +@opindex fno-instrument-function
>>>> +Override @option{-pg} for this translation unit. This is useful with
>>>> +Link Time Optimization (LTO) to override the effects of -pg for a 
>>>> +specific source file.
>>>> +
>>>>  @item -funsigned-char
>>>>  @opindex funsigned-char
>>>>  Let the type @code{char} be unsigned, like @code{unsigned char}.
>>>> diff --git a/gcc/testsuite/g++.dg/fno-instrument-function.C b/gcc/testsuite/g++.dg/fno-instrument-function.C
>>>> new file mode 100644
>>>> index 0000000..e2f6518
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/g++.dg/fno-instrument-function.C
>>>> @@ -0,0 +1,18 @@
>>>> +/* Test -fno-instrument-function */
>>>> +/* { dg-do compile } */
>>>> +/* { dg-options "-pg -fno-instrument-function" } */
>>>> +/* { dg-final { scan-assembler-not "mcount" } } */
>>>> +/* Origin: Andi Kleen */
>>>> +extern void foobar(const char *);
>>>> +
>>>> +void func(void)
>>>> +{
>>>> +  foobar ("Hello world\n");
>>>> +}
>>>> +
>>>> +void func2(void)
>>>> +{
>>>> +  int i;
>>>> +  for (i = 0; i < 10; i++)
>>>> +    foobar ("Hello world");
>>>> +}
>>>> diff --git a/gcc/testsuite/gcc.dg/fno-instrument-function.c b/gcc/testsuite/gcc.dg/fno-instrument-function.c
>>>> new file mode 100644
>>>> index 0000000..9c68fa8
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.dg/fno-instrument-function.c
>>>> @@ -0,0 +1,24 @@
>>>> +/* Test -fno-instrument-function */
>>>> +/* { dg-do compile } */
>>>> +/* { dg-options "-pg -fno-instrument-function" } */
>>>> +/* { dg-final { scan-assembler-not "mcount" } } */
>>>> +/* Origin: Andi Kleen */
>>>> +extern void foobar(char *);
>>>> +
>>>> +void func(void)
>>>> +{
>>>> +  foobar ("Hello world\n");
>>>> +}
>>>> +
>>>> +void func2(void)
>>>> +{
>>>> +  int i;
>>>> +  for (i = 0; i < 10; i++)
>>>> +    foobar ("Hello world");
>>>> +}
>>>> +
>>>> +void func3(a)
>>>> +char *a;
>>>> +{
>>>> +  foobar("Hello world");
>>>> +}

-- 
ak@linux.intel.com -- Speaking for myself only


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