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Re: [PATCH 1/3][GCC] Add new target hook asm_post_cfi_startproc

On 11/5/18 5:18 AM, Sam Tebbs wrote:

On 11/05/2018 07:54 AM, Richard Biener wrote:
On Fri, 2 Nov 2018, Sam Tebbs wrote:

On 11/02/2018 05:28 PM, Sam Tebbs wrote:

Hi all,

This patch adds a new target hook called "asm_post_cfi_startproc". This hook is
intended to be used by the aarch64 backend to emit a directive that enables
support for unwinding frames signed with the pointer authentication B-key. This
hook is triggered after the ".cfi_startproc" directive is emitted in

Bootstrapped on aarch64-none-linux-gnu and tested on aarch64-none-elf with no regressions.

Ok for trunk?
Can you explain why existing prologue/cfi emission points are not

I couldn't find any target hooks that were triggered at the
assembly-printing level at the correct point in time (after
.cfi_startproc is emitted), please do point me to one if that is not the

An alternative could have been to implement a new reg_note but that
would have meant adding target-specific code to target-agnostic files
and wouldn't have been as flexible.

And this seems consistent with the other stuff in dwarf2out_do_cfi_startproc. You might amend the documentation to mention that the expected use is to add more .cfi_* directives. OK with that change.


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