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Date: Tue, 15 Sep 2015 09:36:17 +0800
From: "Wangnan (F)" <wangnan0@huawei.com>
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To: Arnaldo Carvalho de Melo <acme@redhat.com>
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Subject: Re: [PATCH 19/27] perf tools: Introduce regs_query_register_offset()
 for x86
References: <1441523623-152703-1-git-send-email-wangnan0@huawei.com> <1441523623-152703-20-git-send-email-wangnan0@huawei.com> <20150914213753.GA2834@redhat.com>
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On 2015/9/15 5:37, Arnaldo Carvalho de Melo wrote:
> Em Sun, Sep 06, 2015 at 07:13:35AM +0000, Wang Nan escreveu:
>> regs_query_register_offset() is a helper function which converts
>> register name like "%rax" to offset of a register in 'struct pt_regs',
>> which is required by BPF prologue generator. Since the function is
>> identical, try to reuse the code in arch/x86/kernel/ptrace.c.
>>
>> Comment inside dwarf-regs.c list the differences between this
>> implementation and kernel code.
>>
>> get_arch_regstr() switches to regoffset_table and the old string table
>> is dropped.
> Trying to cherry pick this one, but found this problem, trying to fix by
> adding the prototype somewhere...
>
>
> [acme@zoo linux]$ m
> make: Entering directory '/home/git/linux/tools/perf'
>    BUILD:   Doing 'make -j4' parallel build
>    CC       /tmp/build/perf/arch/x86/util/dwarf-regs.o
>    CC       /tmp/build/perf/arch/x86/util/intel-pt.o
> arch/x86/util/dwarf-regs.c:122:5: error: no previous prototype for
> ‘regs_query_register_offset’ [-Werror=missing-prototypes]
>   int regs_query_register_offset(const char *name)
>       ^
> cc1: all warnings being treated as errors
> /home/git/linux/tools/build/Makefile.build:70: recipe for target
> '/tmp/build/perf/arch/x86/util/dwarf-regs.o' failed
> make[5]: *** [/tmp/build/perf/arch/x86/util/dwarf-regs.o] Error 1

This patch depends on patch 18/27: "perf tools: Add BPF_PROLOGUE
config options for further patches" because I wanted to first create
the infrastructure then add regs_qurey_register_offset() arch by arch.

I think split 18/27 into two patch should be better. First one adds
HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET, let the second one consider bpf 
prologue.

Thanks.