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unwind-dw2-xtensa.c: New.

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* config/xtensa/unwind-dw2-xtensa.c: New.
	* config/xtensa/unwind-dw2-xtensa.h: New.
	* config/xtensa/xtensa.h (MUST_USE_SJLJ_EXCEPTIONS): Remove.
	(DWARF2_UNWIND_INFO): Remove.
	(DWARF_FRAME_REGISTERS): Define.
	(EH_RETURN_DATA_REGNO): Define.
	* config/xtensa/xtensa.md (UNSPECV_EH_RETURN): Define.
	(eh_return): New.
	* config/xtensa/t-xtensa (LIB2ADDEH): Define.

Co-Authored-By: Bob Wilson <bob.wilson@acm.org>

From-SVN: r130160
This commit is contained in:
Sterling Augustine 2007-11-13 22:41:50 +00:00 • committed by Bob Wilson
parent b423089ec2
commit 6eb065e62c
6 changed files with 646 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
gcc/ChangeLog
View file

@ -1,3 +1,16 @@
2007-11-13 Sterling Augustine <sterling@tensilica.com>
Bob Wilson <bob.wilson@acm.org>
* config/xtensa/unwind-dw2-xtensa.c: New.
* config/xtensa/unwind-dw2-xtensa.h: New.
* config/xtensa/xtensa.h (MUST_USE_SJLJ_EXCEPTIONS): Remove.
(DWARF2_UNWIND_INFO): Remove.
(DWARF_FRAME_REGISTERS): Define.
(EH_RETURN_DATA_REGNO): Define.
* config/xtensa/xtensa.md (UNSPECV_EH_RETURN): Define.
(eh_return): New.
* config/xtensa/t-xtensa (LIB2ADDEH): Define.
2007-11-13 Jakub Jelinek <jakub@redhat.com>
* doc/invoke.texi: Fix description of -fsched-stalled-insns=0,

2
gcc/config/xtensa/t-xtensa
View file

@ -11,6 +11,8 @@ LIB1ASMFUNCS = _mulsi3 _divsi3 _modsi3 _udivsi3 _umodsi3 \
_truncdfsf2 _extendsfdf2
LIB2FUNCS_EXTRA = $(srcdir)/config/xtensa/lib2funcs.S
LIB2ADDEH = $(srcdir)/config/xtensa/unwind-dw2-xtensa.c \
$(srcdir)/unwind-dw2-fde.c $(srcdir)/unwind-sjlj.c $(srcdir)/unwind-c.c
$(T)crti.o: $(srcdir)/config/xtensa/crti.asm $(GCC_PASSES)
$(GCC_FOR_TARGET) $(GCC_CFLAGS) $(MULTILIB_CFLAGS) $(INCLUDES) \

546
gcc/config/xtensa/unwind-dw2-xtensa.c Normal file
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@ -0,0 +1,546 @@
/* DWARF2 exception handling and frame unwinding for Xtensa.
Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
2007
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 into combinations with other programs,
and to distribute those combinations 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 a combined
executable.)
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. */
#include "tconfig.h"
#include "tsystem.h"
#include "coretypes.h"
#include "tm.h"
#include "dwarf2.h"
#include "unwind.h"
#ifdef __USING_SJLJ_EXCEPTIONS__
# define NO_SIZE_OF_ENCODED_VALUE
#endif
#include "unwind-pe.h"
#include "unwind-dw2-fde.h"
#include "unwind-dw2-xtensa.h"
#ifndef __USING_SJLJ_EXCEPTIONS__
/* The standard CIE and FDE structures work fine for Xtensa but the
variable-size register window save areas are not a good fit for the rest
of the standard DWARF unwinding mechanism. Nor is that mechanism
necessary, since the register save areas are always in fixed locations
in each stack frame. This file is a stripped down and customized version
of the standard DWARF unwinding code. It needs to be customized to have
builtin logic for finding the save areas and also to track the stack
pointer value (besides the CFA) while unwinding since the primary save
area is located below the stack pointer. It is stripped down to reduce
code size and ease the maintenance burden of tracking changes in the
standard version of the code. */
#ifndef DWARF_REG_TO_UNWIND_COLUMN
#define DWARF_REG_TO_UNWIND_COLUMN(REGNO) (REGNO)
#endif
#define XTENSA_RA_FIELD_MASK 0x3FFFFFFF
/* This is the register and unwind state for a particular frame. This
provides the information necessary to unwind up past a frame and return
to its caller. */
struct _Unwind_Context
{
/* Track register window save areas of 4 registers each, instead of
keeping separate addresses for the individual registers. */
_Unwind_Word *reg[4];
void *cfa;
void *sp;
void *ra;
/* Cache the 2 high bits to replace the window size in return addresses. */
_Unwind_Word ra_high_bits;
void *lsda;
struct dwarf_eh_bases bases;
/* Signal frame context. */
#define SIGNAL_FRAME_BIT ((~(_Unwind_Word) 0 >> 1) + 1)
_Unwind_Word flags;
/* 0 for now, can be increased when further fields are added to
struct _Unwind_Context. */
_Unwind_Word version;
};
/* Read unaligned data from the instruction buffer. */
union unaligned
{
void *p;
} __attribute__ ((packed));
static void uw_update_context (struct _Unwind_Context *, _Unwind_FrameState *);
static _Unwind_Reason_Code uw_frame_state_for (struct _Unwind_Context *,
_Unwind_FrameState *);
static inline void *
read_pointer (const void *p) { const union unaligned *up = p; return up->p; }
static inline _Unwind_Word
_Unwind_IsSignalFrame (struct _Unwind_Context *context)
{
return (context->flags & SIGNAL_FRAME_BIT) ? 1 : 0;
}
static inline void
_Unwind_SetSignalFrame (struct _Unwind_Context *context, int val)
{
if (val)
context->flags |= SIGNAL_FRAME_BIT;
else
context->flags &= ~SIGNAL_FRAME_BIT;
}
/* Get the value of register INDEX as saved in CONTEXT. */
inline _Unwind_Word
_Unwind_GetGR (struct _Unwind_Context *context, int index)
{
_Unwind_Word *ptr;
index = DWARF_REG_TO_UNWIND_COLUMN (index);
ptr = context->reg[index >> 2] + (index & 3);
return *ptr;
}
/* Get the value of the CFA as saved in CONTEXT. */
_Unwind_Word
_Unwind_GetCFA (struct _Unwind_Context *context)
{
return (_Unwind_Ptr) context->cfa;
}
/* Overwrite the saved value for register INDEX in CONTEXT with VAL. */
inline void
_Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val)
{
_Unwind_Word *ptr;
index = DWARF_REG_TO_UNWIND_COLUMN (index);
ptr = context->reg[index >> 2] + (index & 3);
*ptr = val;
}
/* Retrieve the return address for CONTEXT. */
inline _Unwind_Ptr
_Unwind_GetIP (struct _Unwind_Context *context)
{
return (_Unwind_Ptr) context->ra;
}
/* Retrieve the return address and flag whether that IP is before
or after first not yet fully executed instruction. */
inline _Unwind_Ptr
_Unwind_GetIPInfo (struct _Unwind_Context *context, int *ip_before_insn)
{
*ip_before_insn = _Unwind_IsSignalFrame (context);
return (_Unwind_Ptr) context->ra;
}
/* Overwrite the return address for CONTEXT with VAL. */
inline void
_Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val)
{
context->ra = (void *) val;
}
void *
_Unwind_GetLanguageSpecificData (struct _Unwind_Context *context)
{
return context->lsda;
}
_Unwind_Ptr
_Unwind_GetRegionStart (struct _Unwind_Context *context)
{
return (_Unwind_Ptr) context->bases.func;
}
void *
_Unwind_FindEnclosingFunction (void *pc)
{
struct dwarf_eh_bases bases;
const struct dwarf_fde *fde = _Unwind_Find_FDE (pc-1, &bases);
if (fde)
return bases.func;
else
return NULL;
}
_Unwind_Ptr
_Unwind_GetDataRelBase (struct _Unwind_Context *context)
{
return (_Unwind_Ptr) context->bases.dbase;
}
_Unwind_Ptr
_Unwind_GetTextRelBase (struct _Unwind_Context *context)
{
return (_Unwind_Ptr) context->bases.tbase;
}
#ifdef MD_UNWIND_SUPPORT
#include MD_UNWIND_SUPPORT
#endif
/* Extract any interesting information from the CIE for the translation
unit F belongs to. Return a pointer to the byte after the augmentation,
or NULL if we encountered an undecipherable augmentation. */
static const unsigned char *
extract_cie_info (const struct dwarf_cie *cie, struct _Unwind_Context *context,
_Unwind_FrameState *fs)
{
const unsigned char *aug = cie->augmentation;
const unsigned char *p = aug + strlen ((const char *)aug) + 1;
const unsigned char *ret = NULL;
_uleb128_t utmp;
_sleb128_t stmp;
/* g++ v2 "eh" has pointer immediately following augmentation string,
so it must be handled first. */
if (aug[0] == 'e' && aug[1] == 'h')
{
fs->eh_ptr = read_pointer (p);
p += sizeof (void *);
aug += 2;
}
/* Immediately following the augmentation are the code and
data alignment and return address column. */
p = read_uleb128 (p, &utmp);
p = read_sleb128 (p, &stmp);
if (cie->version == 1)
fs->retaddr_column = *p++;
else
{
p = read_uleb128 (p, &utmp);
fs->retaddr_column = (_Unwind_Word)utmp;
}
fs->lsda_encoding = DW_EH_PE_omit;
/* If the augmentation starts with 'z', then a uleb128 immediately
follows containing the length of the augmentation field following
the size. */
if (*aug == 'z')
{
p = read_uleb128 (p, &utmp);
ret = p + utmp;
fs->saw_z = 1;
++aug;
}
/* Iterate over recognized augmentation subsequences. */
while (*aug != '\0')
{
/* "L" indicates a byte showing how the LSDA pointer is encoded. */
if (aug[0] == 'L')
{
fs->lsda_encoding = *p++;
aug += 1;
}
/* "R" indicates a byte indicating how FDE addresses are encoded. */
else if (aug[0] == 'R')
{
fs->fde_encoding = *p++;
aug += 1;
}
/* "P" indicates a personality routine in the CIE augmentation. */
else if (aug[0] == 'P')
{
_Unwind_Ptr personality;
p = read_encoded_value (context, *p, p + 1, &personality);
fs->personality = (_Unwind_Personality_Fn) personality;
aug += 1;
}
/* "S" indicates a signal frame. */
else if (aug[0] == 'S')
{
fs->signal_frame = 1;
aug += 1;
}
/* Otherwise we have an unknown augmentation string.
Bail unless we saw a 'z' prefix. */
else
return ret;
}
return ret ? ret : p;
}
/* Given the _Unwind_Context CONTEXT for a stack frame, look up the FDE for
its caller and decode it into FS. This function also sets the
lsda member of CONTEXT, as it is really information
about the caller's frame. */
static _Unwind_Reason_Code
uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs)
{
const struct dwarf_fde *fde;
const struct dwarf_cie *cie;
const unsigned char *aug;
int window_size;
_Unwind_Word *ra_ptr;
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)
{
#ifdef MD_FALLBACK_FRAME_STATE_FOR
_Unwind_Reason_Code reason;
/* Couldn't find frame unwind info for this function. Try a
target-specific fallback mechanism. This will necessarily
not provide a personality routine or LSDA. */
reason = MD_FALLBACK_FRAME_STATE_FOR (context, fs);
if (reason != _URC_END_OF_STACK)
return reason;
/* 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. */
return _URC_FATAL_PHASE1_ERROR;
/* Locate augmentation for the fde. */
aug = (const unsigned char *) fde + sizeof (*fde);
aug += 2 * size_of_encoded_value (fs->fde_encoding);
if (fs->saw_z)
{
_uleb128_t i;
aug = read_uleb128 (aug, &i);
}
if (fs->lsda_encoding != DW_EH_PE_omit)
{
_Unwind_Ptr lsda;
aug = read_encoded_value (context, fs->lsda_encoding, aug, &lsda);
context->lsda = (void *) lsda;
}
}
/* Find the window size from the high bits of the return address. */
if (ra_ptr)
window_size = (*ra_ptr >> 30) * 4;
else
window_size = 8;
fs->retaddr_column = window_size;
return _URC_NO_REASON;
}
static void
uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
{
struct _Unwind_Context orig_context = *context;
_Unwind_Word *sp, *cfa, *next_cfa;
int i;
if (fs->signal_frame)
{
cfa = (_Unwind_Word *) fs->signal_regs[1];
next_cfa = (_Unwind_Word *) cfa[-3];
for (i = 0; i < 4; i++)
context->reg[i] = fs->signal_regs + (i << 2);
}
else
{
int window_size = fs->retaddr_column >> 2;
sp = (_Unwind_Word *) orig_context.sp;
cfa = (_Unwind_Word *) orig_context.cfa;
next_cfa = (_Unwind_Word *) cfa[-3];
/* Registers a0-a3 are in the save area below sp. */
context->reg[0] = sp - 4;
/* Find the extra save area below next_cfa. */
for (i = 1; i < window_size; i++)
context->reg[i] = next_cfa - 4 * (1 + window_size - i);
/* Remaining registers rotate from previous save areas. */
for (i = window_size; i < 4; i++)
context->reg[i] = orig_context.reg[i - window_size];
}
context->sp = cfa;
context->cfa = next_cfa;
_Unwind_SetSignalFrame (context, fs->signal_frame);
}
/* CONTEXT describes the unwind state for a frame, and FS describes the FDE
of its caller. Update CONTEXT to refer to the caller as well. Note
that the lsda member is not updated here, but later in
uw_frame_state_for. */
static void
uw_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
{
uw_update_context_1 (context, 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);
}
static void
uw_advance_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
{
uw_update_context (context, fs);
}
/* Fill in CONTEXT for top-of-stack. The only valid registers at this
level will be the return address and the CFA. */
#define uw_init_context(CONTEXT) \
do \
{ \
__builtin_unwind_init (); \
uw_init_context_1 (CONTEXT, __builtin_dwarf_cfa (), \
__builtin_return_address (0)); \
} \
while (0)
static void
uw_init_context_1 (struct _Unwind_Context *context, void *outer_cfa,
void *outer_ra)
{
void *ra = __builtin_return_address (0);
void *cfa = __builtin_dwarf_cfa ();
_Unwind_FrameState fs;
memset (context, 0, sizeof (struct _Unwind_Context));
context->ra = ra;
memset (&fs, 0, sizeof (fs));
fs.retaddr_column = 8;
context->sp = cfa;
context->cfa = outer_cfa;
context->ra_high_bits =
((_Unwind_Word) uw_init_context_1) & ~XTENSA_RA_FIELD_MASK;
uw_update_context_1 (context, &fs);
context->ra = outer_ra;
}
/* Install TARGET into CURRENT so that we can return to it. This is a
macro because __builtin_eh_return must be invoked in the context of
our caller. */
#define uw_install_context(CURRENT, TARGET) \
do \
{ \
long offset = uw_install_context_1 ((CURRENT), (TARGET)); \
void *handler = __builtin_frob_return_addr ((TARGET)->ra); \
__builtin_eh_return (offset, handler); \
} \
while (0)
static long
uw_install_context_1 (struct _Unwind_Context *current,
struct _Unwind_Context *target)
{
long i;
/* The eh_return insn assumes a window size of 8, so don't bother copying
the save areas for registers a8-a15 since they won't be reloaded. */
for (i = 0; i < 2; ++i)
{
void *c = current->reg[i];
void *t = target->reg[i];
if (t && c && t != c)
memcpy (c, t, 4 * sizeof (_Unwind_Word));
}
return 0;
}
static inline _Unwind_Ptr
uw_identify_context (struct _Unwind_Context *context)
{
return _Unwind_GetCFA (context);
}
#include "unwind.inc"
#if defined (USE_GAS_SYMVER) && defined (SHARED) && defined (USE_LIBUNWIND_EXCEPTIONS)
alias (_Unwind_Backtrace);
alias (_Unwind_DeleteException);
alias (_Unwind_FindEnclosingFunction);
alias (_Unwind_ForcedUnwind);
alias (_Unwind_GetDataRelBase);
alias (_Unwind_GetTextRelBase);
alias (_Unwind_GetCFA);
alias (_Unwind_GetGR);
alias (_Unwind_GetIP);
alias (_Unwind_GetLanguageSpecificData);
alias (_Unwind_GetRegionStart);
alias (_Unwind_RaiseException);
alias (_Unwind_Resume);
alias (_Unwind_Resume_or_Rethrow);
alias (_Unwind_SetGR);
alias (_Unwind_SetIP);
#endif
#endif /* !USING_SJLJ_EXCEPTIONS */

57
gcc/config/xtensa/unwind-dw2-xtensa.h Normal file
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@ -0,0 +1,57 @@
/* DWARF2 frame unwind data structure for Xtensa.
Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2007
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 into combinations with other programs,
and to distribute those combinations 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 a combined
executable.)
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. */
/* A target can override (perhaps for backward compatibility) how
many dwarf2 columns are unwound. */
#ifndef DWARF_FRAME_REGISTERS
#define DWARF_FRAME_REGISTERS FIRST_PSEUDO_REGISTER
#endif
/* Xtensa's variable-size register window save areas can be unwound without
any unwind info. This is a stripped down version of the standard DWARF
_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;
unsigned char fde_encoding;
unsigned char lsda_encoding;
unsigned char saw_z;
unsigned char signal_frame;
void *eh_ptr;
/* Saved registers for a signal frame. */
_Unwind_Word *signal_regs;
} _Unwind_FrameState;

11
gcc/config/xtensa/xtensa.h
View file

@ -1062,12 +1062,15 @@ typedef struct xtensa_args
/* How to start an assembler comment. */
#define ASM_COMMENT_START "#"
/* Generate DWARF2 unwind info to get the DW_AT_frame_base set correctly,
even though we don't yet use it for unwinding. */
#define MUST_USE_SJLJ_EXCEPTIONS 1
#define DWARF2_UNWIND_INFO 1
/* Exception handling. Xtensa uses much of the standard DWARF2 unwinding
machinery, but the variable size register window save areas are too
complicated to efficiently describe with CFI entries. The CFA must
still be specified in DWARF so that DW_AT_frame_base is set correctly
for debugging. */
#define INCOMING_RETURN_ADDR_RTX gen_rtx_REG (Pmode, 0)
#define DWARF_FRAME_RETURN_COLUMN DWARF_FRAME_REGNUM (0)
#define DWARF_FRAME_REGISTERS 16
#define EH_RETURN_DATA_REGNO(N) ((N) < 2 ? (N) + 2 : INVALID_REGNUM)
/* Xtensa constant pool breaks the devices in crtstuff.c to control
section in where code resides. We have to write it as asm code. Use

21
gcc/config/xtensa/xtensa.md
View file

@ -35,6 +35,7 @@
(UNSPECV_MEMW 3)
(UNSPECV_S32RI 4)
(UNSPECV_S32C1I 5)
(UNSPECV_EH_RETURN 6)
])
;; This code iterator allows signed and unsigned widening multiplications
@ -1600,6 +1601,26 @@
DONE;
})
;; Stuff an address into the return address register along with the window
;; size in the high bits. Because we don't have the window size of the
;; previous frame, assume the function called out with a CALL8 since that
;; is what compilers always use. Note: __builtin_frob_return_addr has
;; already been applied to the handler, but the generic version doesn't
;; allow us to frob it quite enough, so we just frob here.
(define_insn_and_split "eh_return"
[(set (reg:SI A0_REG)
(unspec_volatile:SI [(match_operand:SI 0 "register_operand" "r")]
UNSPECV_EH_RETURN))
(clobber (match_scratch:SI 1 "=r"))]
""
"#"
"reload_completed"
[(set (match_dup 1) (ashift:SI (match_dup 0) (const_int 2)))
(set (match_dup 1) (plus:SI (match_dup 1) (const_int 2)))
(set (reg:SI A0_REG) (rotatert:SI (match_dup 1) (const_int 2)))]
"")
;; Setting up a frame pointer is tricky for Xtensa because GCC doesn't
;; know if a frame pointer is required until the reload pass, and
;; because there may be an incoming argument value in the hard frame