| Message ID | 20180204203902.GA10037@host1.jankratochvil.net |
|---|---|
| State | New |
| Headers | show |
On Sun, 4 Feb 2018 21:39:23 +0100 Jan Kratochvil <jan.kratochvil@redhat.com> wrote: > 2018-02-04 Jan Kratochvil <jan.kratochvil@redhat.com> > > * rs6000-tdep.c (skip_prologue): Fix stwux encoding. > Okay.
On Mon, 05 Feb 2018 19:46:21 +0100, Kevin Buettner wrote: > On Sun, 4 Feb 2018 21:39:23 +0100 Jan Kratochvil <jan.kratochvil@redhat.com> wrote: > > 2018-02-04 Jan Kratochvil <jan.kratochvil@redhat.com> > > > > * rs6000-tdep.c (skip_prologue): Fix stwux encoding. > > > > Okay. Checked in: 72dd27306224497c8ba97f391d30b774d4d973fb Jan
Thank you for this patch! The mask was still too permissive (see PR gdb/18295), so I submitted another patch fixing that. Sorry I didn't see this before! Previously the stdux mask also allowed stwux (and more), and the if body was the same, so it was accidentally working for stwux, despite the tautological compare.
--- a/gdb/rs6000-tdep.c +++ b/gdb/rs6000-tdep.c @@ -1857,7 +1857,7 @@ skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc, CORE_ADDR lim_pc, offset = fdata->offset; continue; } - else if ((op & 0xfc1f016a) == 0x7c01016e) + else if ((op & 0xfc1f016e) == 0x7c01016e) { /* stwux rX,r1,rY */ /* No way to figure out what r1 is going to be. */ fdata->frameless = 0;
Hi, with gcc-8.0.1-0.9.fc28.x86_64 I get: ../../gdb/rs6000-tdep.c: In function 'CORE_ADDR skip_prologue(gdbarch*, CORE_ADDR, CORE_ADDR, rs6000_framedata*)': ../../gdb/rs6000-tdep.c:1911:34: error: bitwise comparison always evaluates to false [-Werror=tautological-compare] else if ((op & 0xfc1f016a) == 0x7c01016e) ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~ The code is there since: commit 98f08d3d9b69b344bb8b0cd2a4bda1cf4d966e20 Author: Kevin Buettner <kevinb@redhat.com> Date: Thu May 29 19:47:14 2003 +0000 From Jimi X <jimix@watson.ibm.com>: * rs6000-tdep.c (skip_prologue): Improve support for 64-bit code. So I do not think we can find the original author. https://www.ibm.com/support/knowledgecenter/en/ssw_aix_72/com.ibm.aix.alangref/idalangref_stwux_stux_instrs.htm says bit 21 - 30 = 183 Those are bits 1..10 in normal bit order: 183<<1 = 0x16e OK for check-in? Jan gdb/ChangeLog 2018-02-04 Jan Kratochvil <jan.kratochvil@redhat.com> * rs6000-tdep.c (skip_prologue): Fix stwux encoding.