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* [gcc(refs/vendors/ARM/heads/CVE-2023-4039/gcc-7)] aarch64: Rename locals_offset to bytes_above_locals
@ 2023-09-12 15:23 Richard Sandiford
0 siblings, 0 replies; only message in thread
From: Richard Sandiford @ 2023-09-12 15:23 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:e628f34ef3a7db3a75aa146b3e75099a9c431d20
commit e628f34ef3a7db3a75aa146b3e75099a9c431d20
Author: Richard Sandiford <richard.sandiford@arm.com>
Date: Tue Jun 27 11:25:40 2023 +0100
aarch64: Rename locals_offset to bytes_above_locals
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.
Diff:
---
gcc/config/aarch64/aarch64.c | 12 +++++++-----
gcc/config/aarch64/aarch64.h | 6 +++---
2 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 12df8bb783c7..27dd3b7a62b3 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -2890,7 +2890,8 @@ aarch64_layout_frame (void)
+ cfun->machine->frame.bytes_below_hard_fp,
STACK_BOUNDARY / BITS_PER_UNIT);
- cfun->machine->frame.locals_offset = cfun->machine->frame.saved_varargs_size;
+ cfun->machine->frame.bytes_above_locals
+ = cfun->machine->frame.saved_varargs_size;
cfun->machine->frame.initial_adjust = 0;
cfun->machine->frame.final_adjust = 0;
@@ -2951,7 +2952,8 @@ aarch64_layout_frame (void)
cfun->machine->frame.bytes_below_hard_fp
= cfun->machine->frame.final_adjust;
cfun->machine->frame.hard_fp_offset = cfun->machine->frame.callee_adjust;
- cfun->machine->frame.locals_offset = cfun->machine->frame.hard_fp_offset;
+ cfun->machine->frame.bytes_above_locals
+ = cfun->machine->frame.hard_fp_offset;
}
else
{
@@ -5653,14 +5655,14 @@ aarch64_initial_elimination_offset (unsigned from, unsigned to)
if (from == FRAME_POINTER_REGNUM)
return cfun->machine->frame.hard_fp_offset
- - cfun->machine->frame.locals_offset;
+ - cfun->machine->frame.bytes_above_locals;
}
if (to == STACK_POINTER_REGNUM)
{
if (from == FRAME_POINTER_REGNUM)
- return cfun->machine->frame.frame_size
- - cfun->machine->frame.locals_offset;
+ return cfun->machine->frame.frame_size
+ - cfun->machine->frame.bytes_above_locals;
}
return cfun->machine->frame.frame_size;
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index 6dc6ef2b989b..79af237ada67 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -565,10 +565,10 @@ struct GTY (()) aarch64_frame
always a multiple of STACK_BOUNDARY. */
HOST_WIDE_INT 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. */
- HOST_WIDE_INT locals_offset;
+ HOST_WIDE_INT bytes_above_locals;
/* Offset from the base of the frame (incomming SP) to the
hard_frame_pointer. This value is always a multiple of
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