On 22/12/13 17:42, Eric Botcazou wrote:
> Hi,
>
> this is the last issue with nested APCS frames according to our testing.
> When
> the IP register needs to be preserved on entry and r3 isn't free and there are
> no arguments to push, the prologue creates a slot above the frame, so various
> internal offsets need to be adjusted. One has been missed, leading to:
>
> sub ip, fp, #20
> fldmfdd ip!, {d8}
> sub sp, fp, #16
> ldmfd sp, {r3, fp, sp, pc}
>
> in the epilogue of the nested frame. That's wrong because the difference
> between the 2 immediates must be equal to the size of the saved FP registers.
>
> Tested on ARM/VxWorks (where it fixes several ACATS tests at -O2) and
> ARM/EABI, OK for the mainline?
>
>
> 2013-12-22 Eric Botcazou <ebotca...@adacore.com>
>
> * config/arm/arm.c (arm_get_frame_offsets): Revamp long lines.
> (arm_expand_epilogue_apcs_frame): Take into account the number of bytes
> used to save the static chain register in the computation of the offset
> from which the FP registers need to be restored.
>
>
> 2013-12-22 Eric Botcazou <ebotca...@adacore.com>
>
> * gcc.target/arm/neon-nested-apcs.c: New test.
>
>
OK, modulo the 2 nits below.
> /* In Thumb mode this is incorrect, but never used. */
> - offsets->frame = offsets->saved_args + (frame_pointer_needed ? 4 : 0) +
> - arm_compute_static_chain_stack_bytes();
> + offsets->frame
> + = offsets->saved_args
> + + arm_compute_static_chain_stack_bytes ()
> + + (frame_pointer_needed ? 4 : 0);
There should be brackets around the entire expression when split across
mulitple lines, so that auto-indentation is correctly preserved: ie
offsets->frame
= (expression_in_backets_when
- over_mulitple_lines);
> /* Find the offset of the floating-point save area in the frame. */
> - floats_from_frame = offsets->saved_args - offsets->frame;
> + floats_from_frame
> + = offsets->saved_args
> + + arm_compute_static_chain_stack_bytes ()
> + - offsets->frame;
>
Same here.
R.
