diff options
Diffstat (limited to '0105-aarch64-Avoid-a-use-of-callee_offset.patch')
| -rw-r--r-- | 0105-aarch64-Avoid-a-use-of-callee_offset.patch | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/0105-aarch64-Avoid-a-use-of-callee_offset.patch b/0105-aarch64-Avoid-a-use-of-callee_offset.patch new file mode 100644 index 0000000..9b6d88c --- /dev/null +++ b/0105-aarch64-Avoid-a-use-of-callee_offset.patch @@ -0,0 +1,72 @@ +From 901269e14884a86c532b99fb41d5f46b519344f0 Mon Sep 17 00:00:00 2001 +From: Richard Sandiford <richard.sandiford@arm.com> +Date: Tue, 27 Jun 2023 11:12:21 +0100 +Subject: [PATCH] aarch64: Avoid a use of callee_offset + +When we emit the frame chain, i.e. when we reach Here in this statement +of aarch64_expand_prologue: + + if (emit_frame_chain) + { + // Here + ... + } + +the stack is in one of two states: + +- We've allocated up to the frame chain, but no more. + +- We've allocated the whole frame, and the frame chain is within easy + reach of the new SP. + +The offset of the frame chain from the current SP is available +in aarch64_frame as callee_offset. It is also available as the +chain_offset local variable, where the latter is calculated from other +data. (However, chain_offset is not always equal to callee_offset when +!emit_frame_chain, so chain_offset isn't redundant.) + +In c600df9a4060da3c6121ff4d0b93f179eafd69d1 I switched to using +chain_offset for the initialisation of the hard frame pointer: + + aarch64_add_offset (Pmode, hard_frame_pointer_rtx, +- stack_pointer_rtx, callee_offset, ++ stack_pointer_rtx, chain_offset, + tmp1_rtx, tmp0_rtx, frame_pointer_needed); + +But the later REG_CFA_ADJUST_CFA handling still used callee_offset. + +I think the difference is harmless, but it's more logical for the +CFA note to be in sync, and it's more convenient for later patches +if it uses chain_offset. + +gcc/ + * config/aarch64/aarch64.c (aarch64_expand_prologue): Use + chain_offset rather than callee_offset. +--- + gcc/config/aarch64/aarch64.c | 4 +--- + 1 file changed, 1 insertion(+), 3 deletions(-) + +diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c +index 368bb394105..2aaf187bcc3 100644 +--- a/gcc/config/aarch64/aarch64.c ++++ b/gcc/config/aarch64/aarch64.c +@@ -8299,7 +8299,6 @@ aarch64_expand_prologue (void) + poly_int64 initial_adjust = frame.initial_adjust; + HOST_WIDE_INT callee_adjust = frame.callee_adjust; + poly_int64 final_adjust = frame.final_adjust; +- poly_int64 callee_offset = frame.callee_offset; + poly_int64 sve_callee_adjust = frame.sve_callee_adjust; + poly_int64 below_hard_fp_saved_regs_size + = frame.below_hard_fp_saved_regs_size; +@@ -8408,8 +8407,7 @@ aarch64_expand_prologue (void) + implicit. */ + if (!find_reg_note (insn, REG_CFA_ADJUST_CFA, NULL_RTX)) + { +- rtx src = plus_constant (Pmode, stack_pointer_rtx, +- callee_offset); ++ rtx src = plus_constant (Pmode, stack_pointer_rtx, chain_offset); + add_reg_note (insn, REG_CFA_ADJUST_CFA, + gen_rtx_SET (hard_frame_pointer_rtx, src)); + } +-- +2.39.3 |