From 6c633d454a09f6fd5f85f54d46f57a733967c667 Mon Sep 17 00:00:00 2001
From: Bob Wilson <bob.wilson@acm.org>
Date: Fri, 18 Jan 2008 01:37:53 +0000
Subject: [PATCH] unwind-dw2-xtensa.h (_Unwind_FrameState): Remove pc field and
add signal_ra.
* config/xtensa/unwind-dw2-xtensa.h (_Unwind_FrameState): Remove pc
field and add signal_ra.
* config/xtensa/unwind-dw2-xtensa.c (uw_frame_state_for): Remove
assignments to frame state pc. Move end of stack check after
MD_FALLBACK_FRAME_STATE_FOR.
(uw_update_context_1): Use frame state signal_regs if set, instead
of checking signal_frame flag.
(uw_update_context): Use frame state signal_ra if set.
* config/xtensa/linux.h (MD_UNWIND_SUPPORT): Define.
* config/xtensa/linux-unwind.h: New file.
From-SVN: r131622
---
gcc/ChangeLog | 13 ++++
gcc/config/xtensa/linux-unwind.h | 101 ++++++++++++++++++++++++++
gcc/config/xtensa/linux.h | 6 +-
gcc/config/xtensa/unwind-dw2-xtensa.c | 29 +++++---
gcc/config/xtensa/unwind-dw2-xtensa.h | 6 +-
5 files changed, 138 insertions(+), 17 deletions(-)
create mode 100644 gcc/config/xtensa/linux-unwind.h
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2b1662a25967..987a47bf6b8c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
+2007-01-17 Bob Wilson <bob.wilson@acm.org>
+
+ * config/xtensa/unwind-dw2-xtensa.h (_Unwind_FrameState): Remove pc
+ field and add signal_ra.
+ * config/xtensa/unwind-dw2-xtensa.c (uw_frame_state_for): Remove
+ assignments to frame state pc. Move end of stack check after
+ MD_FALLBACK_FRAME_STATE_FOR.
+ (uw_update_context_1): Use frame state signal_regs if set, instead
+ of checking signal_frame flag.
+ (uw_update_context): Use frame state signal_ra if set.
+ * config/xtensa/linux.h (MD_UNWIND_SUPPORT): Define.
+ * config/xtensa/linux-unwind.h: New file.
+
2007-01-18 Bernhard Fischer <aldot@gcc.gnu.org>
* modulo-sched.c (get_sched_window): Fix comment typo.
diff --git a/gcc/config/xtensa/linux-unwind.h b/gcc/config/xtensa/linux-unwind.h
new file mode 100644
index 000000000000..18daff2d133c
--- /dev/null
+++ b/gcc/config/xtensa/linux-unwind.h
@@ -0,0 +1,101 @@
+/* DWARF2 EH unwinding support for Xtensa.
+ Copyright (C) 2008 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+In addition to the permissions in the GNU General Public License, the
+Free Software Foundation gives you unlimited permission to link the
+compiled version of this file with other programs, and to distribute
+those programs without any restriction coming from the use of this
+file. (The General Public License restrictions do apply in other
+respects; for example, they cover modification of the file, and
+distribution when not linked into another program.)
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING. If not, write to
+the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA. */
+
+/* Do code reading to identify a signal frame, and set the frame
+ state data appropriately. See unwind-dw2-xtensa.c for the structs.
+ Don't use this at all if inhibit_libc is used. */
+
+#ifndef inhibit_libc
+
+#include <signal.h>
+#include <sys/ucontext.h>
+
+/* Encoded bytes for Xtensa instructions:
+ movi a2, __NR_rt_sigreturn
+ syscall
+ entry (first byte only)
+ Some of the bytes are endian-dependent. */
+
+#define MOVI_BYTE0 0x22
+#define MOVI_BYTE2 225 /* __NR_rt_sigreturn */
+#define SYSC_BYTE0 0
+#define SYSC_BYTE2 0
+
+#ifdef __XTENSA_EB__
+#define MOVI_BYTE1 0x0a
+#define SYSC_BYTE1 0x05
+#define ENTRY_BYTE 0x6c
+#else
+#define MOVI_BYTE1 0xa0
+#define SYSC_BYTE1 0x50
+#define ENTRY_BYTE 0x36
+#endif
+
+#define MD_FALLBACK_FRAME_STATE_FOR xtensa_fallback_frame_state
+
+static _Unwind_Reason_Code
+xtensa_fallback_frame_state (struct _Unwind_Context *context,
+ _Unwind_FrameState *fs)
+{
+ unsigned char *pc = context->ra;
+ struct sigcontext *sc;
+
+ struct rt_sigframe {
+ struct siginfo info;
+ struct ucontext uc;
+ } *rt_;
+
+ /* movi a2, __NR_rt_sigreturn; syscall */
+ if (pc[0] != MOVI_BYTE0
+ || pc[1] != MOVI_BYTE1
+ || pc[2] != MOVI_BYTE2
+ || pc[3] != SYSC_BYTE0
+ || pc[4] != SYSC_BYTE1
+ || pc[5] != SYSC_BYTE2)
+ return _URC_END_OF_STACK;
+
+ rt_ = context->sp;
+ sc = &rt_->uc.uc_mcontext;
+ fs->signal_regs = (_Unwind_Word *) sc->sc_a;
+
+ /* If the signal arrived just before an ENTRY instruction, find the return
+ address and pretend the signal arrived before executing the CALL. */
+ if (*(unsigned char *) sc->sc_pc == ENTRY_BYTE)
+ {
+ unsigned callinc = (sc->sc_ps >> 16) & 3;
+ fs->signal_ra = ((sc->sc_a[callinc << 2] & XTENSA_RA_FIELD_MASK)
+ | context->ra_high_bits) - 3;
+ }
+ else
+ fs->signal_ra = sc->sc_pc;
+
+ fs->signal_frame = 1;
+ return _URC_NO_REASON;
+}
+
+#endif /* ifdef inhibit_libc */
diff --git a/gcc/config/xtensa/linux.h b/gcc/config/xtensa/linux.h
index 6a2c81a1d5dc..69ab626b2011 100644
--- a/gcc/config/xtensa/linux.h
+++ b/gcc/config/xtensa/linux.h
@@ -1,6 +1,7 @@
/* Xtensa Linux configuration.
Derived from the configuration for GCC for Intel i386 running Linux.
- Copyright (C) 2001, 2002, 2003, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2002, 2003, 2006, 2007, 2008
+ Free Software Foundation, Inc.
This file is part of GCC.
@@ -59,3 +60,6 @@ along with GCC; see the file COPYING3. If not see
/* Always enable "-fpic" for Xtensa Linux. */
#define XTENSA_ALWAYS_PIC 1
+
+#define MD_UNWIND_SUPPORT "config/xtensa/linux-unwind.h"
+
diff --git a/gcc/config/xtensa/unwind-dw2-xtensa.c b/gcc/config/xtensa/unwind-dw2-xtensa.c
index 1dd4f9dee3f1..22b492f9eadf 100644
--- a/gcc/config/xtensa/unwind-dw2-xtensa.c
+++ b/gcc/config/xtensa/unwind-dw2-xtensa.c
@@ -1,6 +1,6 @@
/* DWARF2 exception handling and frame unwinding for Xtensa.
Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
- 2007
+ 2007, 2008
Free Software Foundation, Inc.
This file is part of GCC.
@@ -325,10 +325,6 @@ uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs)
memset (fs, 0, sizeof (*fs));
context->lsda = 0;
- ra_ptr = context->reg[0];
- if (ra_ptr && *ra_ptr == 0)
- return _URC_END_OF_STACK;
-
fde = _Unwind_Find_FDE (context->ra + _Unwind_IsSignalFrame (context) - 1,
&context->bases);
if (fde == NULL)
@@ -341,16 +337,13 @@ uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs)
reason = MD_FALLBACK_FRAME_STATE_FOR (context, fs);
if (reason != _URC_END_OF_STACK)
return reason;
+#endif
/* The frame was not recognized and handled by the fallback function,
but it is not really the end of the stack. Fall through here and
unwind it anyway. */
-#endif
- fs->pc = context->ra;
}
else
{
- fs->pc = context->bases.func;
-
cie = get_cie (fde);
if (extract_cie_info (cie, context, fs) == NULL)
/* CIE contained unknown augmentation. */
@@ -373,6 +366,15 @@ uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs)
}
}
+ /* Check for the end of the stack. This needs to be checked after
+ the MD_FALLBACK_FRAME_STATE_FOR check for signal frames because
+ the contents of context->reg[0] are undefined at a signal frame,
+ and register a0 may appear to be zero. (The return address in
+ context->ra comes from register a4 or a8). */
+ ra_ptr = context->reg[0];
+ if (ra_ptr && *ra_ptr == 0)
+ return _URC_END_OF_STACK;
+
/* Find the window size from the high bits of the return address. */
if (ra_ptr)
window_size = (*ra_ptr >> 30) * 4;
@@ -391,7 +393,7 @@ uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
_Unwind_Word *sp, *cfa, *next_cfa;
int i;
- if (fs->signal_frame)
+ if (fs->signal_regs)
{
cfa = (_Unwind_Word *) fs->signal_regs[1];
next_cfa = (_Unwind_Word *) cfa[-3];
@@ -437,8 +439,11 @@ uw_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
/* Compute the return address now, since the return address column
can change from frame to frame. */
- context->ra = (void *) ((_Unwind_GetGR (context, fs->retaddr_column)
- & XTENSA_RA_FIELD_MASK) | context->ra_high_bits);
+ if (fs->signal_ra != 0)
+ context->ra = (void *) fs->signal_ra;
+ else
+ context->ra = (void *) ((_Unwind_GetGR (context, fs->retaddr_column)
+ & XTENSA_RA_FIELD_MASK) | context->ra_high_bits);
}
static void
diff --git a/gcc/config/xtensa/unwind-dw2-xtensa.h b/gcc/config/xtensa/unwind-dw2-xtensa.h
index 99341172eac4..f88f7f3a84ab 100644
--- a/gcc/config/xtensa/unwind-dw2-xtensa.h
+++ b/gcc/config/xtensa/unwind-dw2-xtensa.h
@@ -1,5 +1,5 @@
/* DWARF2 frame unwind data structure for Xtensa.
- Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2007
+ Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2007, 2008
Free Software Foundation, Inc.
This file is part of GCC.
@@ -39,9 +39,6 @@
_Unwind_FrameState. */
typedef struct
{
- /* The PC described by the current frame state. */
- void *pc;
-
/* The information we care about from the CIE/FDE. */
_Unwind_Personality_Fn personality;
_Unwind_Word retaddr_column;
@@ -53,5 +50,6 @@ typedef struct
/* Saved registers for a signal frame. */
_Unwind_Word *signal_regs;
+ _Unwind_Word signal_ra;
} _Unwind_FrameState;
--
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