gcc/aarch64-Rename-hard_fp_offset-to-bytes_above_hard_fp.patch

From da0132a4cd2eb26ecaff20578bf2753b20014223 Mon Sep 17 00:00:00 2001
From: Richard Sandiford <richard.sandiford@arm.com>
Date: Tue, 27 Jun 2023 11:28:11 +0100
Subject: [PATCH] aarch64: Rename hard_fp_offset to bytes_above_hard_fp
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Similarly to the previous locals_offset patch, hard_fp_offset
was described as:

  /* Offset from the base of the frame (incomming SP) to the
     hard_frame_pointer.  This value is always a multiple of
     STACK_BOUNDARY.  */
  poly_int64 hard_fp_offset;

which again took an “upside-down” view: higher offsets meant lower
addresses.  This patch renames the field to bytes_above_hard_fp instead.

gcc/
	* config/aarch64/aarch64.h (aarch64_frame::hard_fp_offset): Rename
	to...
	(aarch64_frame::bytes_above_hard_fp): ...this.
	* config/aarch64/aarch64.c (aarch64_layout_frame)
	(aarch64_expand_prologue): Update accordingly.
	(aarch64_initial_elimination_offset): Likewise.
---
 gcc/config/aarch64/aarch64.c | 29 ++++++++++++++++-------------
 gcc/config/aarch64/aarch64.h |  6 +++---
 2 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 27dd3b7a62b..e3c36abb1e3 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -2881,12 +2881,12 @@ aarch64_layout_frame (void)
   HOST_WIDE_INT varargs_and_saved_regs_size
     = offset + cfun->machine->frame.saved_varargs_size;
 
-  cfun->machine->frame.hard_fp_offset
+  cfun->machine->frame.bytes_above_hard_fp
     = ROUND_UP (varargs_and_saved_regs_size + get_frame_size (),
 		STACK_BOUNDARY / BITS_PER_UNIT);
 
   cfun->machine->frame.frame_size
-    = ROUND_UP (cfun->machine->frame.hard_fp_offset
+    = ROUND_UP (cfun->machine->frame.bytes_above_hard_fp
 		+ cfun->machine->frame.bytes_below_hard_fp,
 		STACK_BOUNDARY / BITS_PER_UNIT);
 
@@ -2917,7 +2917,7 @@ aarch64_layout_frame (void)
   else if ((cfun->machine->frame.bytes_below_hard_fp
 	    + cfun->machine->frame.saved_regs_size < 512)
 	   && !(cfun->calls_alloca
-		&& cfun->machine->frame.hard_fp_offset < max_push_offset))
+		&& cfun->machine->frame.bytes_above_hard_fp < max_push_offset))
     {
       /* Frame with small area below the saved registers:
 	 sub sp, sp, frame_size
@@ -2925,16 +2925,17 @@ aarch64_layout_frame (void)
 	 stp reg3, reg4, [sp, bytes_below_hard_fp + 16]  */
       cfun->machine->frame.initial_adjust = cfun->machine->frame.frame_size;
       cfun->machine->frame.callee_offset
-	= cfun->machine->frame.frame_size - cfun->machine->frame.hard_fp_offset;
+	= cfun->machine->frame.frame_size - cfun->machine->frame.bytes_above_hard_fp;
     }
-  else if (cfun->machine->frame.hard_fp_offset < max_push_offset)
+  else if (cfun->machine->frame.bytes_above_hard_fp < max_push_offset)
     {
       /* Frame with large area below the saved registers, but with a
 	 small area above:
-	 stp reg1, reg2, [sp, -hard_fp_offset]!
+	 stp reg1, reg2, [sp, -bytes_above_hard_fp]!
 	 stp reg3, reg4, [sp, 16]
 	 sub sp, sp, bytes_below_hard_fp  */
-      cfun->machine->frame.callee_adjust = cfun->machine->frame.hard_fp_offset;
+      cfun->machine->frame.callee_adjust
+	= cfun->machine->frame.bytes_above_hard_fp;
       cfun->machine->frame.final_adjust
 	= cfun->machine->frame.frame_size - cfun->machine->frame.callee_adjust;
     }
@@ -2951,19 +2952,21 @@ aarch64_layout_frame (void)
 	= cfun->machine->frame.frame_size - cfun->machine->frame.callee_adjust;
       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.bytes_above_hard_fp
+	= cfun->machine->frame.callee_adjust;
       cfun->machine->frame.bytes_above_locals
-	= cfun->machine->frame.hard_fp_offset;
+	= cfun->machine->frame.bytes_above_hard_fp;
     }
   else
     {
       /* General case:
-	 sub sp, sp, hard_fp_offset
+	 sub sp, sp, bytes_above_hard_fp
 	 stp x29, x30, [sp, 0]
 	 add x29, sp, 0
 	 stp reg3, reg4, [sp, 16]
 	 sub sp, sp, bytes_below_hard_fp  */
-      cfun->machine->frame.initial_adjust = cfun->machine->frame.hard_fp_offset;
+      cfun->machine->frame.initial_adjust
+	= cfun->machine->frame.bytes_above_hard_fp;
       cfun->machine->frame.final_adjust
 	= cfun->machine->frame.frame_size - cfun->machine->frame.initial_adjust;
     }
@@ -5651,10 +5654,10 @@ aarch64_initial_elimination_offset (unsigned from, unsigned to)
   if (to == HARD_FRAME_POINTER_REGNUM)
     {
       if (from == ARG_POINTER_REGNUM)
-	return cfun->machine->frame.hard_fp_offset;
+	return cfun->machine->frame.bytes_above_hard_fp;
 
       if (from == FRAME_POINTER_REGNUM)
-	return cfun->machine->frame.hard_fp_offset
+	return cfun->machine->frame.bytes_above_hard_fp
 	       - cfun->machine->frame.bytes_above_locals;
     }
 
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index 79af237ada6..35ba9681e03 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -570,10 +570,10 @@ struct GTY (()) aarch64_frame
      STACK_BOUNDARY.  */
   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
+  /* The number of bytes between the hard_frame_pointer and the top of
+     the frame (the incomming SP).  This value is always a multiple of
      STACK_BOUNDARY.  */
-  HOST_WIDE_INT hard_fp_offset;
+  HOST_WIDE_INT bytes_above_hard_fp;
 
   /* The size of the frame.  This value is the offset from base of the
    * frame (incomming SP) to the stack_pointer.  This value is always
-- 
2.39.3