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Re: [PATCH][AArch64] Add more cfi annotations to tlsdesc entry points

On 12/13/2016 07:05 AM, Florian Weimer wrote:

On 12/09/2016 06:38 PM, Richard Henderson wrote:

On 12/09/2016 05:23 AM, Szabolcs Nagy wrote:

     stp    x1,  x2, [sp, #32+16*0]
+    cfi_rel_offset (x1, 32)
+    cfi_rel_offset (x2, 32+8)
     stp    x3,  x4, [sp, #32+16*1]
+    cfi_rel_offset (x3, 32+16)
+    cfi_rel_offset (x4, 32+24)


FWIW, you'll produce equivalent, but smaller unwind info if you put all of the
cfi_rel_offsets together (constrained by the assembly for when the original
register values change.  So

    stp    x1, x2, [sp, #32+16*0]
    stp    x3, x4, [sp, #32+16*1]
    cfi_rel_offset (x1, 32)
    cfi_rel_offset (x2, 32+8)
    cfi_rel_offset (x3, 32+16)
    cfi_rel_offset (x4, 32+24)


Will this cause problems with async cancellation?
No, because the registers have not been modified. All this does is eliminate extra "advance" opcodes. 

r~
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