Quick top post reporting that the fix for the post-amble code is in place in 
llvm -r282174 :

> Begin forwarded message:
> 
> From: bugzilla-daemon[ at ]llvm.org
> Subject: [Bug 26519] Clang 3.8.0's "Target: powerpc-unknown-freebsd11.0" code 
> generation is violating the SVR4 ABI (SEGV can result)
> Date: September 22, 2016 at 10:23:21 AM PDT
> To: <markmi[ at ]dsl-only.net>
> 
> Krzysztof Parzyszek changed bug 26519 
> What  Removed Added
> Status        REOPENED        RESOLVED
> Resolution    ---     FIXED
> 
> Comment # 11 on bug 26519 from Krzysztof Parzyszek
> Committed in r282174.
> 
> You are receiving this mail because:
>       • You reported the bug.


===
Mark Millard
markmi at dsl-only.net

On 2016-Sep-12, at 6:40 PM, Mark Millard <markmi at dsl-only.net> wrote:

> On 2016-Sep-10, at 6:56 PM, Mark Millard <markmi at dsl-only.net> wrote:
> 
>> Quick top post: Krzysztof has re-opened llvm bugzilla 26519 because the 
>> post-amble side of things has not been fixed yet. . .
>> 
>> 
>> 
>> Krzysztof Parzyszek changed bug 26519 
>> What Removed Added
>> Status       RESOLVED        REOPENED
>> Resolution   FIXED   ---
>> Comment # 9 on bug 26519 from Krzysztof Parzyszek
>> The post-amble has not been fixed.
>> 
>> You are receiving this mail because:
>>      • You reported the bug.
>> 
>> ===
>> Mark Millard
>> markmi at dsl-only.net
> 
> There is now a code review active for this now, quoting the notice:
> 
>> Comment # 10 on bug 26519 from Krzysztof Parzyszek
>> The epilogue part of the fix: https://reviews.llvm.org/D24466
>> 
>> 
>> Hopefully there is nothing else missing.
>> 
>> You are receiving this mail because:
>>      • You reported the bug.
> 
> ===
> Mark Millard
> markmi at dsl-only.net
> 
> On 2016-Sep-10, at 6:23 PM, Mark Millard <markmi at dsl-only.net> wrote:
>> 
>> On 2016-Sep-10, at 10:18 AM, Dimitry Andric <dim at FreeBSD.org> wrote:
>> 
>>> On 06 Sep 2016, at 15:04, Mark Millard <markmi at dsl-only.net> wrote:
>>>> 
>>>> llvm's bugzilla reports that the stack-handling SVR4 ABI violation for 
>>>> TARGET_ARCH=powerpc has been fixed r280705 (likely on trunk)!
>>> 
>>> I merged the upstream fix to projects/clang390-import:
>>> 
>>> https://svnweb.freebsd.org/changeset/base/305686
>>> 
>>> -Dimitry
>> 
>> Looking at things for this again I've submitted a question to 
>> https://llvm.org/bugs/show_bug.cgi?id=26519 asking if the post-amble code's 
>> side if things was also adjusted (instead of just the pre-amble/"claim" code 
>> side of things).
>> 
>> [I'm not clang/llvm literate so I may have missed interpreted something when 
>> I looked.]
>> 
>> My original submittal also noted the stack pointer adjustment-timing problem 
>> existed on the post-amble side in 3.8.0's code generation (when removing the 
>> frame from the stack):
>> 
>>> 0x1801b8c <Buf_AddBytes+104>:       lwz     r30,24(r31)
>>> 0x1801b90 <Buf_AddBytes+108>:       lwz     r29,20(r31)
>>> 0x1801b94 <Buf_AddBytes+112>:       lwz     r28,16(r31)
>>> 0x1801b98 <Buf_AddBytes+116>:       lwz     r27,12(r31)
>>> 0x1801b9c <Buf_AddBytes+120>:       lwz     r26,8(r31)
>>> 0x1801ba0 <Buf_AddBytes+124>:       addi    r1,r1,32   # Stack pointer 
>>> adjusted first
>>> 0x1801ba4 <Buf_AddBytes+128>:       lwz     r0,4(r1)
>>> 0x1801ba8 <Buf_AddBytes+132>:       lwz     r31,-4(r1) # Then Frame Pointer 
>>> load happens
>>>                                                 # "outside" the new stack 
>>> range.
>>> 0x1801bac <Buf_AddBytes+136>:       mtlr    r0
>>> 0x1801bb0 <Buf_AddBytes+140>:       blr
>> 
>> If such code can still be generated there would still be a time frame 
>> needing a red-zone to protect stack the contents from signals.
>> 
>> Hopefully I'm just wrong and this was fixed too.
>> 
>> 
>> 
>> ===
>> Mark Millard
>> markmi at dsl-only.net
>> 
>> 
> 

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