From 375794feb614cee1f41b710b9cc1b6f25da6c1cb Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Tue, 12 Sep 2023 16:07:15 +0100 Subject: [PATCH 21/32] aarch64: Rename locals_offset to bytes_above_locals MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit locals_offset was described as: /* 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. */ This is implicitly an “upside down” view of the frame: the incoming SP is at offset 0, and anything N bytes below the incoming SP is at offset N (rather than -N). However, reg_offset instead uses a “right way up” view; that is, it views offsets in address terms. Something above X is at a positive offset from X and something below X is at a negative offset from X. Also, even on FRAME_GROWS_DOWNWARD targets like AArch64, target-independent code views offsets in address terms too: locals are allocated at negative offsets to virtual_stack_vars. It seems confusing to have *_offset fields of the same structure using different polarities like this. This patch tries to avoid that by renaming locals_offset to bytes_above_locals. gcc/ * config/aarch64/aarch64.h (aarch64_frame::locals_offset): Rename to... (aarch64_frame::bytes_above_locals): ...this. * config/aarch64/aarch64.cc (aarch64_layout_frame) (aarch64_initial_elimination_offset): Update accordingly. --- gcc/config/aarch64/aarch64.cc | 6 +++--- gcc/config/aarch64/aarch64.h | 6 +++--- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc index 0e9b9717c085..0a22f91520e5 100644 --- a/gcc/config/aarch64/aarch64.cc +++ b/gcc/config/aarch64/aarch64.cc @@ -8598,7 +8598,7 @@ aarch64_layout_frame (void) STACK_BOUNDARY / BITS_PER_UNIT)); frame.frame_size = saved_regs_and_above + frame.bytes_below_saved_regs; - frame.locals_offset = frame.saved_varargs_size; + frame.bytes_above_locals = frame.saved_varargs_size; frame.initial_adjust = 0; frame.final_adjust = 0; @@ -12754,13 +12754,13 @@ aarch64_initial_elimination_offset (unsigned from, unsigned to) return frame.hard_fp_offset; if (from == FRAME_POINTER_REGNUM) - return frame.hard_fp_offset - frame.locals_offset; + return frame.hard_fp_offset - frame.bytes_above_locals; } if (to == STACK_POINTER_REGNUM) { if (from == FRAME_POINTER_REGNUM) - return frame.frame_size - frame.locals_offset; + return frame.frame_size - frame.bytes_above_locals; } return frame.frame_size; diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h index fd820b1be4eb..7ae12d13e2b4 100644 --- a/gcc/config/aarch64/aarch64.h +++ b/gcc/config/aarch64/aarch64.h @@ -791,10 +791,10 @@ struct GTY (()) aarch64_frame 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 + /* The number of bytes between the top of the locals area and the top + of the frame (the incomming SP). This value is always a multiple of STACK_BOUNDARY. */ - poly_int64 locals_offset; + poly_int64 bytes_above_locals; /* Offset from the base of the frame (incomming SP) to the hard_frame_pointer. This value is always a multiple of -- 2.42.0