[src/trunk]: src/lib/libc/arch/alpha/sys Use the DWARF pseudo-register for th...

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/79f47bf3ee89
branches:  trunk
changeset: 1026382:79f47bf3ee89
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sat Nov 20 19:26:20 2021 +0000

description:
Use the DWARF pseudo-register for the signal trampoline return address.

diffstat:

 lib/libc/arch/alpha/sys/__sigtramp2.S |  20 ++++++++++++++++----
 1 files changed, 16 insertions(+), 4 deletions(-)

diffs (47 lines):

diff -r 909270bc9444 -r 79f47bf3ee89 lib/libc/arch/alpha/sys/__sigtramp2.S
--- a/lib/libc/arch/alpha/sys/__sigtramp2.S     Sat Nov 20 19:06:21 2021 +0000
+++ b/lib/libc/arch/alpha/sys/__sigtramp2.S     Sat Nov 20 19:26:20 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: __sigtramp2.S,v 1.7 2021/11/03 04:52:51 thorpej Exp $  */
+/*     $NetBSD: __sigtramp2.S,v 1.8 2021/11/20 19:26:20 thorpej Exp $  */
 
 /*
  * Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
@@ -38,10 +38,20 @@
  *
  *             ucontext structure      [128] == sp + sizeof(siginfo_t)]
  *     sp->    siginfo structure       [0]
+ *
+ * The DWARF register numbers for the general purpose registers are the
+ * same as the architected register numbers.  For Alpha, there is a DWARF
+ * pseudo-register for signal handler return addresses.
  */
 
-#define        CFI_OFFSET_REG(n, r)    .cfi_offset n, r*8
-#define        CFI_OFFSET(r)           CFI_OFFSET_REG(r, r)
+#if defined(__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__)
+#define        DWARF_SIGRETURN_REG             __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__
+#else
+#define        DWARF_SIGRETURN_REG             64
+#endif
+
+#define        CFI_OFFSET_DWARF_REG(d, r)      .cfi_offset d, r*8
+#define        CFI_OFFSET(r)                   CFI_OFFSET_DWARF_REG(r, r)
 
        .cfi_startproc simple
        .cfi_signal_frame
@@ -72,11 +82,13 @@
        CFI_OFFSET(_REG_T9)
        CFI_OFFSET(_REG_T10)
        CFI_OFFSET(_REG_T11)
-       CFI_OFFSET_REG(_REG_RA, _REG_PC)
+       CFI_OFFSET(_REG_RA)
        CFI_OFFSET(_REG_T12)    /* a.k.a. _REG_PV */
        CFI_OFFSET(_REG_AT)
        CFI_OFFSET(_REG_GP)
        CFI_OFFSET(_REG_SP)
+       .cfi_return_column DWARF_SIGRETURN_REG
+       CFI_OFFSET_DWARF_REG(DWARF_SIGRETURN_REG, _REG_PC)
 
 /*
  * The unwind entry includes one instruction slot prior to the trampoline