From d3f6ceecc8a7f128a9e6cb7d8aecf0de81ed9705 Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Tue, 12 Sep 2023 16:19:45 +0100 Subject: [PATCH 15/29] aarch64: Add bytes_below_hard_fp to frame info Following on from the previous bytes_below_saved_regs patch, this one records the number of bytes that are below the hard frame pointer. This eventually replaces below_hard_fp_saved_regs_size. If a frame pointer is not needed, the epilogue adds final_adjust to the stack pointer before restoring registers: aarch64_add_sp (tmp1_rtx, tmp0_rtx, final_adjust, true); Therefore, if the epilogue needs to restore the stack pointer from the hard frame pointer, the directly corresponding offset is: -bytes_below_hard_fp + final_adjust i.e. go from the hard frame pointer to the bottom of the frame, then add the same amount as if we were using the stack pointer from the outset. gcc/ * config/aarch64/aarch64.h (aarch64_frame::bytes_below_hard_fp): New field. * config/aarch64/aarch64.c (aarch64_layout_frame): Initialize it. (aarch64_expand_epilogue): Use it instead of below_hard_fp_saved_regs_size. --- gcc/config/aarch64/aarch64.c | 6 +++--- gcc/config/aarch64/aarch64.h | 5 +++++ 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c index 8fa5a0b25455..e03adf57226f 100644 --- a/gcc/config/aarch64/aarch64.c +++ b/gcc/config/aarch64/aarch64.c @@ -7528,6 +7528,7 @@ aarch64_layout_frame (void) of the callee save area. */ bool saves_below_hard_fp_p = maybe_ne (offset, 0); frame.below_hard_fp_saved_regs_size = offset; + frame.bytes_below_hard_fp = offset + frame.bytes_below_saved_regs; if (frame.emit_frame_chain) { /* FP and LR are placed in the linkage record. */ @@ -9083,8 +9084,7 @@ aarch64_expand_epilogue (bool for_sibcall) 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; + poly_int64 bytes_below_hard_fp = frame.bytes_below_hard_fp; unsigned reg1 = frame.wb_candidate1; unsigned reg2 = frame.wb_candidate2; rtx cfi_ops = NULL; @@ -9140,7 +9140,7 @@ aarch64_expand_epilogue (bool for_sibcall) is restored on the instruction doing the writeback. */ aarch64_add_offset (Pmode, stack_pointer_rtx, hard_frame_pointer_rtx, - -callee_offset - below_hard_fp_saved_regs_size, + -bytes_below_hard_fp + final_adjust, tmp1_rtx, tmp0_rtx, callee_adjust == 0); else /* The case where we need to re-use the register here is very rare, so diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h index 6f0b8c7107e7..21ac920a3fe1 100644 --- a/gcc/config/aarch64/aarch64.h +++ b/gcc/config/aarch64/aarch64.h @@ -846,6 +846,11 @@ struct GTY (()) aarch64_frame are saved below the hard frame pointer. */ poly_int64 below_hard_fp_saved_regs_size; + /* The number of bytes between the bottom of the static frame (the bottom + of the outgoing arguments) and the hard frame pointer. This value is + always a multiple of STACK_BOUNDARY. */ + poly_int64 bytes_below_hard_fp; + /* Offset from the base of the frame (incomming SP) to the top of the locals area. This value is always a multiple of STACK_BOUNDARY. */ -- 2.42.0