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From 82fb69e75c21010f7afc72bb842751164fe8fc72 Mon Sep 17 00:00:00 2001
From: Richard Sandiford <richard.sandiford@arm.com>
Date: Tue, 12 Sep 2023 16:19:46 +0100
Subject: [PATCH 18/29] 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.c (aarch64_layout_frame)
(aarch64_initial_elimination_offset): Update accordingly.
---
gcc/config/aarch64/aarch64.c | 6 +++---
gcc/config/aarch64/aarch64.h | 6 +++---
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index cf5244b7ec08..d54f7a89306f 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -7596,7 +7596,7 @@ 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;
@@ -11758,13 +11758,13 @@ 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 57e672177456..3c5e3dd429dc 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -851,10 +851,10 @@ 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
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