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From: "i at maskray dot me" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/99888] Add powerpc ELFv2 support for
 -fpatchable-function-entry*
Date: Thu, 11 Aug 2022 06:59:55 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99888

Fangrui Song <i at maskray dot me> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |i at maskray dot me

--- Comment #5 from Fangrui Song <i at maskray dot me> ---
* There is a restriction on the number of instructions between the function
label and the .localentry directive.
* For -fpatchable-function-entry=3DN[,M], M nops must precede the function =
label.

On aarch64/x86/etc, these nops are consecutive. Personally I think this
condition can be lifted for PowerPC ELFv2. The runtime library will need to
check st_other or do some instruction inspection, which may be fine.


        nop
        nop
        nop
foo:
.LCF0:
        .cfi_startproc
        addis 2,12,.TOC.-.LCF0@ha
        addi 2,2,.TOC.-.LCF0@l
        .localentry     foo,.-foo
        nop
        nop=