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binutils-gdb/gdb/mips-mdebug-tdep.c

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/* Target-dependent code for the MDEBUG MIPS architecture, for GDB,
the GNU Debugger.
Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software
Foundation, Inc.
This file is part of GDB.
This program 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 of the License, or
(at your option) any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "defs.h"
#include "frame.h"
#include "mips-tdep.h"
#include "trad-frame.h"
#include "block.h"
#include "symtab.h"
#include "objfiles.h"
#include "elf/mips.h"
#include "elf-bfd.h"
#include "gdb_assert.h"
#include "frame-unwind.h"
#include "frame-base.h"
#include "mips-mdebug-tdep.h"
#define PROC_LOW_ADDR(proc) ((proc)->pdr.adr) /* least address */
#define PROC_HIGH_ADDR(proc) ((proc)->high_addr) /* upper address bound */
#define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset)
#define PROC_FRAME_REG(proc) ((proc)->pdr.framereg)
#define PROC_FRAME_ADJUST(proc) ((proc)->frame_adjust)
#define PROC_REG_MASK(proc) ((proc)->pdr.regmask)
#define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask)
#define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset)
#define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset)
#define PROC_PC_REG(proc) ((proc)->pdr.pcreg)
/* FIXME drow/2002-06-10: If a pointer on the host is bigger than a long,
this will corrupt pdr.iline. Fortunately we don't use it. */
#define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->pdr.isym)
#define _PROC_MAGIC_ 0x0F0F0F0F
struct mips_objfile_private
{
bfd_size_type size;
char *contents;
};
/* Global used to communicate between non_heuristic_proc_desc and
compare_pdr_entries within qsort (). */
static bfd *the_bfd;
static int
compare_pdr_entries (const void *a, const void *b)
{
CORE_ADDR lhs = bfd_get_32 (the_bfd, (bfd_byte *) a);
CORE_ADDR rhs = bfd_get_32 (the_bfd, (bfd_byte *) b);
if (lhs < rhs)
return -1;
else if (lhs == rhs)
return 0;
else
return 1;
}
static const struct objfile_data *mips_pdr_data;
static mips_extra_func_info_t
non_heuristic_proc_desc (CORE_ADDR pc, CORE_ADDR *addrptr)
{
CORE_ADDR startaddr;
mips_extra_func_info_t proc_desc;
struct block *b = block_for_pc (pc);
struct symbol *sym;
struct obj_section *sec;
struct mips_objfile_private *priv;
find_pc_partial_function (pc, NULL, &startaddr, NULL);
if (addrptr)
*addrptr = startaddr;
priv = NULL;
sec = find_pc_section (pc);
if (sec != NULL)
{
priv = (struct mips_objfile_private *) objfile_data (sec->objfile, mips_pdr_data);
/* Search the ".pdr" section generated by GAS. This includes most of
the information normally found in ECOFF PDRs. */
the_bfd = sec->objfile->obfd;
if (priv == NULL
&& (the_bfd->format == bfd_object
&& bfd_get_flavour (the_bfd) == bfd_target_elf_flavour
&& elf_elfheader (the_bfd)->e_ident[EI_CLASS] == ELFCLASS64))
{
/* Right now GAS only outputs the address as a four-byte sequence.
This means that we should not bother with this method on 64-bit
targets (until that is fixed). */
priv = obstack_alloc (&sec->objfile->objfile_obstack,
sizeof (struct mips_objfile_private));
priv->size = 0;
set_objfile_data (sec->objfile, mips_pdr_data, priv);
}
else if (priv == NULL)
{
asection *bfdsec;
priv = obstack_alloc (&sec->objfile->objfile_obstack,
sizeof (struct mips_objfile_private));
bfdsec = bfd_get_section_by_name (sec->objfile->obfd, ".pdr");
if (bfdsec != NULL)
{
priv->size = bfd_section_size (sec->objfile->obfd, bfdsec);
priv->contents = obstack_alloc (&sec->objfile->objfile_obstack,
priv->size);
bfd_get_section_contents (sec->objfile->obfd, bfdsec,
priv->contents, 0, priv->size);
/* In general, the .pdr section is sorted. However, in the
presence of multiple code sections (and other corner cases)
it can become unsorted. Sort it so that we can use a faster
binary search. */
qsort (priv->contents, priv->size / 32, 32,
compare_pdr_entries);
}
else
priv->size = 0;
set_objfile_data (sec->objfile, mips_pdr_data, priv);
}
the_bfd = NULL;
if (priv->size != 0)
{
int low, mid, high;
char *ptr;
CORE_ADDR pdr_pc;
low = 0;
high = priv->size / 32;
/* We've found a .pdr section describing this objfile. We want to
find the entry which describes this code address. The .pdr
information is not very descriptive; we have only a function
start address. We have to look for the closest entry, because
the local symbol at the beginning of this function may have
been stripped - so if we ask the symbol table for the start
address we may get a preceding global function. */
/* First, find the last .pdr entry starting at or before PC. */
do
{
mid = (low + high) / 2;
ptr = priv->contents + mid * 32;
pdr_pc = bfd_get_signed_32 (sec->objfile->obfd, ptr);
pdr_pc += ANOFFSET (sec->objfile->section_offsets,
SECT_OFF_TEXT (sec->objfile));
if (pdr_pc > pc)
high = mid;
else
low = mid + 1;
}
while (low != high);
/* Both low and high point one past the PDR of interest. If
both are zero, that means this PC is before any region
covered by a PDR, i.e. pdr_pc for the first PDR entry is
greater than PC. */
if (low > 0)
{
ptr = priv->contents + (low - 1) * 32;
pdr_pc = bfd_get_signed_32 (sec->objfile->obfd, ptr);
pdr_pc += ANOFFSET (sec->objfile->section_offsets,
SECT_OFF_TEXT (sec->objfile));
}
/* We don't have a range, so we have no way to know for sure
whether we're in the correct PDR or a PDR for a preceding
function and the current function was a stripped local
symbol. But if the PDR's PC is at least as great as the
best guess from the symbol table, assume that it does cover
the right area; if a .pdr section is present at all then
nearly every function will have an entry. The biggest exception
will be the dynamic linker stubs; conveniently these are
placed before .text instead of after. */
if (pc >= pdr_pc && pdr_pc >= startaddr)
{
struct symbol *sym = find_pc_function (pc);
if (addrptr)
*addrptr = pdr_pc;
/* Fill in what we need of the proc_desc. */
proc_desc = (mips_extra_func_info_t)
obstack_alloc (&sec->objfile->objfile_obstack,
sizeof (struct mips_extra_func_info));
PROC_LOW_ADDR (proc_desc) = pdr_pc;
/* Only used for dummy frames. */
PROC_HIGH_ADDR (proc_desc) = 0;
PROC_FRAME_OFFSET (proc_desc)
= bfd_get_32 (sec->objfile->obfd, ptr + 20);
PROC_FRAME_REG (proc_desc) = bfd_get_32 (sec->objfile->obfd,
ptr + 24);
PROC_FRAME_ADJUST (proc_desc) = 0;
PROC_REG_MASK (proc_desc) = bfd_get_32 (sec->objfile->obfd,
ptr + 4);
PROC_FREG_MASK (proc_desc) = bfd_get_32 (sec->objfile->obfd,
ptr + 12);
PROC_REG_OFFSET (proc_desc) = bfd_get_32 (sec->objfile->obfd,
ptr + 8);
PROC_FREG_OFFSET (proc_desc)
= bfd_get_32 (sec->objfile->obfd, ptr + 16);
PROC_PC_REG (proc_desc) = bfd_get_32 (sec->objfile->obfd,
ptr + 28);
proc_desc->pdr.isym = (long) sym;
return proc_desc;
}
}
}
if (b == NULL)
return NULL;
if (startaddr > BLOCK_START (b))
{
/* This is the "pathological" case referred to in a comment in
print_frame_info. It might be better to move this check into
symbol reading. */
return NULL;
}
sym = lookup_symbol (MIPS_EFI_SYMBOL_NAME, b, LABEL_DOMAIN, 0, NULL);
/* If we never found a PDR for this function in symbol reading, then
examine prologues to find the information. */
if (sym)
{
proc_desc = (mips_extra_func_info_t) SYMBOL_VALUE (sym);
if (PROC_FRAME_REG (proc_desc) == -1)
return NULL;
else
return proc_desc;
}
else
return NULL;
}
struct mips_frame_cache
{
CORE_ADDR base;
struct trad_frame_saved_reg *saved_regs;
};
static struct mips_frame_cache *
mips_mdebug_frame_cache (struct frame_info *next_frame, void **this_cache)
{
CORE_ADDR startaddr = 0;
mips_extra_func_info_t proc_desc;
struct mips_frame_cache *cache;
struct gdbarch *gdbarch = get_frame_arch (next_frame);
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
/* r0 bit means kernel trap */
int kernel_trap;
/* What registers have been saved? Bitmasks. */
unsigned long gen_mask, float_mask;
if ((*this_cache) != NULL)
return (*this_cache);
cache = FRAME_OBSTACK_ZALLOC (struct mips_frame_cache);
(*this_cache) = cache;
cache->saved_regs = trad_frame_alloc_saved_regs (next_frame);
/* Get the mdebug proc descriptor. */
proc_desc = non_heuristic_proc_desc (frame_pc_unwind (next_frame),
&startaddr);
/* Must be true. This is only called when the sniffer detected a
proc descriptor. */
gdb_assert (proc_desc != NULL);
/* Extract the frame's base. */
cache->base = (frame_unwind_register_signed (next_frame, NUM_REGS + PROC_FRAME_REG (proc_desc))
+ PROC_FRAME_OFFSET (proc_desc) - PROC_FRAME_ADJUST (proc_desc));
kernel_trap = PROC_REG_MASK (proc_desc) & 1;
gen_mask = kernel_trap ? 0xFFFFFFFF : PROC_REG_MASK (proc_desc);
float_mask = kernel_trap ? 0xFFFFFFFF : PROC_FREG_MASK (proc_desc);
/* Must be true. The in_prologue case is left for the heuristic
unwinder. This is always used on kernel traps. */
gdb_assert (!in_prologue (frame_pc_unwind (next_frame), PROC_LOW_ADDR (proc_desc))
|| kernel_trap);
/* Fill in the offsets for the registers which gen_mask says were
saved. */
{
CORE_ADDR reg_position = (cache->base + PROC_REG_OFFSET (proc_desc));
int ireg;
for (ireg = MIPS_NUMREGS - 1; gen_mask; --ireg, gen_mask <<= 1)
if (gen_mask & 0x80000000)
{
cache->saved_regs[NUM_REGS + ireg].addr = reg_position;
reg_position -= mips_abi_regsize (gdbarch);
}
}
/* Fill in the offsets for the registers which float_mask says were
saved. */
{
CORE_ADDR reg_position = (cache->base
+ PROC_FREG_OFFSET (proc_desc));
int ireg;
/* Fill in the offsets for the float registers which float_mask
says were saved. */
for (ireg = MIPS_NUMREGS - 1; float_mask; --ireg, float_mask <<= 1)
if (float_mask & 0x80000000)
{
if (mips_abi_regsize (gdbarch) == 4
&& TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
{
/* On a big endian 32 bit ABI, floating point registers
are paired to form doubles such that the most
significant part is in $f[N+1] and the least
significant in $f[N] vis: $f[N+1] ||| $f[N]. The
registers are also spilled as a pair and stored as a
double.
When little-endian the least significant part is
stored first leading to the memory order $f[N] and
then $f[N+1].
Unfortunately, when big-endian the most significant
part of the double is stored first, and the least
significant is stored second. This leads to the
registers being ordered in memory as firt $f[N+1] and
then $f[N].
For the big-endian case make certain that the
addresses point at the correct (swapped) locations
$f[N] and $f[N+1] pair (keep in mind that
reg_position is decremented each time through the
loop). */
if ((ireg & 1))
cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->fp0 + ireg]
.addr = reg_position - mips_abi_regsize (gdbarch);
else
cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->fp0 + ireg]
.addr = reg_position + mips_abi_regsize (gdbarch);
}
else
cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->fp0 + ireg]
.addr = reg_position;
reg_position -= mips_abi_regsize (gdbarch);
}
cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->pc]
= cache->saved_regs[NUM_REGS + MIPS_RA_REGNUM];
}
/* SP_REGNUM, contains the value and not the address. */
trad_frame_set_value (cache->saved_regs, NUM_REGS + MIPS_SP_REGNUM, cache->base);
return (*this_cache);
}
static void
mips_mdebug_frame_this_id (struct frame_info *next_frame, void **this_cache,
struct frame_id *this_id)
{
struct mips_frame_cache *info = mips_mdebug_frame_cache (next_frame,
this_cache);
(*this_id) = frame_id_build (info->base, frame_func_unwind (next_frame));
}
static void
mips_mdebug_frame_prev_register (struct frame_info *next_frame,
void **this_cache,
int regnum, int *optimizedp,
enum lval_type *lvalp, CORE_ADDR *addrp,
int *realnump, void *valuep)
{
struct mips_frame_cache *info = mips_mdebug_frame_cache (next_frame,
this_cache);
trad_frame_get_prev_register (next_frame, info->saved_regs, regnum,
optimizedp, lvalp, addrp, realnump, valuep);
}
static const struct frame_unwind mips_mdebug_frame_unwind =
{
NORMAL_FRAME,
mips_mdebug_frame_this_id,
mips_mdebug_frame_prev_register
};
static const struct frame_unwind *
mips_mdebug_frame_sniffer (struct frame_info *next_frame)
{
CORE_ADDR pc = frame_pc_unwind (next_frame);
CORE_ADDR startaddr = 0;
mips_extra_func_info_t proc_desc;
int kernel_trap;
/* Don't use this on MIPS16. */
if (mips_pc_is_mips16 (pc))
return NULL;
/* Only use the mdebug frame unwinder on mdebug frames where all the
registers have been saved. Leave hard cases such as no mdebug or
in prologue for the heuristic unwinders. */
proc_desc = non_heuristic_proc_desc (pc, &startaddr);
if (proc_desc == NULL)
return NULL;
/* Not sure exactly what kernel_trap means, but if it means the
kernel saves the registers without a prologue doing it, we better
not examine the prologue to see whether registers have been saved
yet. */
kernel_trap = PROC_REG_MASK (proc_desc) & 1;
if (kernel_trap)
return &mips_mdebug_frame_unwind;
/* In any frame other than the innermost or a frame interrupted by a
signal, we assume that all registers have been saved. This
assumes that all register saves in a function happen before the
first function call. */
if (!in_prologue (pc, PROC_LOW_ADDR (proc_desc)))
return &mips_mdebug_frame_unwind;
return NULL;
}
static CORE_ADDR
mips_mdebug_frame_base_address (struct frame_info *next_frame,
void **this_cache)
{
struct mips_frame_cache *info = mips_mdebug_frame_cache (next_frame,
this_cache);
return info->base;
}
static const struct frame_base mips_mdebug_frame_base = {
&mips_mdebug_frame_unwind,
mips_mdebug_frame_base_address,
mips_mdebug_frame_base_address,
mips_mdebug_frame_base_address
};
static const struct frame_base *
mips_mdebug_frame_base_sniffer (struct frame_info *next_frame)
{
if (mips_mdebug_frame_sniffer (next_frame) != NULL)
return &mips_mdebug_frame_base;
else
return NULL;
}
void
mips_mdebug_append_sniffers (struct gdbarch *gdbarch)
{
frame_unwind_append_sniffer (gdbarch, mips_mdebug_frame_sniffer);
frame_base_append_sniffer (gdbarch, mips_mdebug_frame_base_sniffer);
}
extern void _initialize_mips_mdebug_tdep (void);
void
_initialize_mips_mdebug_tdep (void)
{
mips_pdr_data = register_objfile_data ();
}
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