976 lines
31 KiB
C
976 lines
31 KiB
C
/* Target-dependent code for the MIPS architecture, for GDB, the GNU Debugger.
|
||
Copyright 1988, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
|
||
Contributed by Alessandro Forin(af@cs.cmu.edu) at CMU
|
||
and by Per Bothner(bothner@cs.wisc.edu) at U.Wisconsin.
|
||
|
||
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., 675 Mass Ave, Cambridge, MA 02139, USA. */
|
||
|
||
#include "defs.h"
|
||
#include "frame.h"
|
||
#include "inferior.h"
|
||
#include "symtab.h"
|
||
#include "value.h"
|
||
#include "gdbcmd.h"
|
||
#include "language.h"
|
||
#include "gdbcore.h"
|
||
#include "symfile.h"
|
||
#include "objfiles.h"
|
||
|
||
#include "opcode/mips.h"
|
||
|
||
#define VM_MIN_ADDRESS (unsigned)0x400000
|
||
|
||
static int mips_in_lenient_prologue PARAMS ((CORE_ADDR, CORE_ADDR));
|
||
|
||
/* Some MIPS boards don't support floating point, so we permit the
|
||
user to turn it off. */
|
||
int mips_fpu = 1;
|
||
|
||
/* Heuristic_proc_start may hunt through the text section for a long
|
||
time across a 2400 baud serial line. Allows the user to limit this
|
||
search. */
|
||
static unsigned int heuristic_fence_post = 0;
|
||
|
||
#define PROC_LOW_ADDR(proc) ((proc)->pdr.adr) /* least address */
|
||
#define PROC_HIGH_ADDR(proc) ((proc)->pdr.iline) /* upper address bound */
|
||
#define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset)
|
||
#define PROC_FRAME_REG(proc) ((proc)->pdr.framereg)
|
||
#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)
|
||
#define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->pdr.isym)
|
||
#define _PROC_MAGIC_ 0x0F0F0F0F
|
||
#define PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym == _PROC_MAGIC_)
|
||
#define SET_PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym = _PROC_MAGIC_)
|
||
|
||
struct linked_proc_info
|
||
{
|
||
struct mips_extra_func_info info;
|
||
struct linked_proc_info *next;
|
||
} *linked_proc_desc_table = NULL;
|
||
|
||
|
||
#define READ_FRAME_REG(fi, regno) read_next_frame_reg((fi)->next, regno)
|
||
|
||
static int
|
||
read_next_frame_reg(fi, regno)
|
||
FRAME fi;
|
||
int regno;
|
||
{
|
||
/* If it is the frame for sigtramp we have a complete sigcontext
|
||
immediately below the frame and we get the saved registers from there.
|
||
If the stack layout for sigtramp changes we might have to change these
|
||
constants and the companion fixup_sigtramp in mipsread.c */
|
||
#ifndef SIGFRAME_BASE
|
||
#define SIGFRAME_BASE 0x12c /* sizeof(sigcontext) */
|
||
#define SIGFRAME_PC_OFF (-SIGFRAME_BASE + 2 * 4)
|
||
#define SIGFRAME_REGSAVE_OFF (-SIGFRAME_BASE + 3 * 4)
|
||
#endif
|
||
for (; fi; fi = fi->next)
|
||
if (in_sigtramp(fi->pc, 0)) {
|
||
int offset;
|
||
if (regno == PC_REGNUM) offset = SIGFRAME_PC_OFF;
|
||
else if (regno < 32) offset = SIGFRAME_REGSAVE_OFF + regno * 4;
|
||
else return 0;
|
||
return read_memory_integer(fi->frame + offset, 4);
|
||
}
|
||
else if (regno == SP_REGNUM) return fi->frame;
|
||
else if (fi->saved_regs->regs[regno])
|
||
return read_memory_integer(fi->saved_regs->regs[regno], 4);
|
||
return read_register(regno);
|
||
}
|
||
|
||
int
|
||
mips_frame_saved_pc(frame)
|
||
FRAME frame;
|
||
{
|
||
mips_extra_func_info_t proc_desc = frame->proc_desc;
|
||
int pcreg = proc_desc ? PROC_PC_REG(proc_desc) : RA_REGNUM;
|
||
|
||
if (proc_desc && PROC_DESC_IS_DUMMY(proc_desc))
|
||
return read_memory_integer(frame->frame - 4, 4);
|
||
|
||
return read_next_frame_reg(frame, pcreg);
|
||
}
|
||
|
||
static struct mips_extra_func_info temp_proc_desc;
|
||
static struct frame_saved_regs temp_saved_regs;
|
||
|
||
/* This fencepost looks highly suspicious to me. Removing it also
|
||
seems suspicious as it could affect remote debugging across serial
|
||
lines. */
|
||
|
||
static CORE_ADDR
|
||
heuristic_proc_start(pc)
|
||
CORE_ADDR pc;
|
||
{
|
||
CORE_ADDR start_pc = pc;
|
||
CORE_ADDR fence = start_pc - heuristic_fence_post;
|
||
|
||
if (start_pc == 0) return 0;
|
||
|
||
if (heuristic_fence_post == UINT_MAX
|
||
|| fence < VM_MIN_ADDRESS)
|
||
fence = VM_MIN_ADDRESS;
|
||
|
||
/* search back for previous return */
|
||
for (start_pc -= 4; ; start_pc -= 4)
|
||
if (start_pc < fence)
|
||
{
|
||
/* It's not clear to me why we reach this point when
|
||
stop_soon_quietly, but with this test, at least we
|
||
don't print out warnings for every child forked (eg, on
|
||
decstation). 22apr93 rich@cygnus.com. */
|
||
if (!stop_soon_quietly)
|
||
{
|
||
static int blurb_printed = 0;
|
||
|
||
if (fence == VM_MIN_ADDRESS)
|
||
warning("Hit beginning of text section without finding");
|
||
else
|
||
warning("Hit heuristic-fence-post without finding");
|
||
|
||
warning("enclosing function for address 0x%x", pc);
|
||
if (!blurb_printed)
|
||
{
|
||
printf_filtered ("\
|
||
This warning occurs if you are debugging a function without any symbols\n\
|
||
(for example, in a stripped executable). In that case, you may wish to\n\
|
||
increase the size of the search with the `set heuristic-fence-post' command.\n\
|
||
\n\
|
||
Otherwise, you told GDB there was a function where there isn't one, or\n\
|
||
(more likely) you have encountered a bug in GDB.\n");
|
||
blurb_printed = 1;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
else if (ABOUT_TO_RETURN(start_pc))
|
||
break;
|
||
|
||
start_pc += 8; /* skip return, and its delay slot */
|
||
#if 0
|
||
/* skip nops (usually 1) 0 - is this */
|
||
while (start_pc < pc && read_memory_integer (start_pc, 4) == 0)
|
||
start_pc += 4;
|
||
#endif
|
||
return start_pc;
|
||
}
|
||
|
||
static mips_extra_func_info_t
|
||
heuristic_proc_desc(start_pc, limit_pc, next_frame)
|
||
CORE_ADDR start_pc, limit_pc;
|
||
FRAME next_frame;
|
||
{
|
||
CORE_ADDR sp = next_frame ? next_frame->frame : read_register (SP_REGNUM);
|
||
CORE_ADDR cur_pc;
|
||
int frame_size;
|
||
int has_frame_reg = 0;
|
||
int reg30; /* Value of $r30. Used by gcc for frame-pointer */
|
||
unsigned long reg_mask = 0;
|
||
|
||
if (start_pc == 0) return NULL;
|
||
memset(&temp_proc_desc, '\0', sizeof(temp_proc_desc));
|
||
memset(&temp_saved_regs, '\0', sizeof(struct frame_saved_regs));
|
||
PROC_LOW_ADDR(&temp_proc_desc) = start_pc;
|
||
|
||
if (start_pc + 200 < limit_pc) limit_pc = start_pc + 200;
|
||
restart:
|
||
frame_size = 0;
|
||
for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += 4) {
|
||
char buf[4];
|
||
unsigned long word;
|
||
int status;
|
||
|
||
status = read_memory_nobpt (cur_pc, buf, 4);
|
||
if (status) memory_error (status, cur_pc);
|
||
word = extract_unsigned_integer (buf, 4);
|
||
|
||
if ((word & 0xFFFF0000) == 0x27bd0000) /* addiu $sp,$sp,-i */
|
||
frame_size += (-word) & 0xFFFF;
|
||
else if ((word & 0xFFFF0000) == 0x23bd0000) /* addu $sp,$sp,-i */
|
||
frame_size += (-word) & 0xFFFF;
|
||
else if ((word & 0xFFE00000) == 0xafa00000) { /* sw reg,offset($sp) */
|
||
int reg = (word & 0x001F0000) >> 16;
|
||
reg_mask |= 1 << reg;
|
||
temp_saved_regs.regs[reg] = sp + (short)word;
|
||
}
|
||
else if ((word & 0xFFFF0000) == 0x27be0000) { /* addiu $30,$sp,size */
|
||
if ((unsigned short)word != frame_size)
|
||
reg30 = sp + (unsigned short)word;
|
||
else if (!has_frame_reg) {
|
||
int alloca_adjust;
|
||
has_frame_reg = 1;
|
||
reg30 = read_next_frame_reg(next_frame, 30);
|
||
alloca_adjust = reg30 - (sp + (unsigned short)word);
|
||
if (alloca_adjust > 0) {
|
||
/* FP > SP + frame_size. This may be because
|
||
/* of an alloca or somethings similar.
|
||
* Fix sp to "pre-alloca" value, and try again.
|
||
*/
|
||
sp += alloca_adjust;
|
||
goto restart;
|
||
}
|
||
}
|
||
}
|
||
else if ((word & 0xFFE00000) == 0xafc00000) { /* sw reg,offset($30) */
|
||
int reg = (word & 0x001F0000) >> 16;
|
||
reg_mask |= 1 << reg;
|
||
temp_saved_regs.regs[reg] = reg30 + (short)word;
|
||
}
|
||
}
|
||
if (has_frame_reg) {
|
||
PROC_FRAME_REG(&temp_proc_desc) = 30;
|
||
PROC_FRAME_OFFSET(&temp_proc_desc) = 0;
|
||
}
|
||
else {
|
||
PROC_FRAME_REG(&temp_proc_desc) = SP_REGNUM;
|
||
PROC_FRAME_OFFSET(&temp_proc_desc) = frame_size;
|
||
}
|
||
PROC_REG_MASK(&temp_proc_desc) = reg_mask;
|
||
PROC_PC_REG(&temp_proc_desc) = RA_REGNUM;
|
||
return &temp_proc_desc;
|
||
}
|
||
|
||
static mips_extra_func_info_t
|
||
find_proc_desc(pc, next_frame)
|
||
CORE_ADDR pc;
|
||
FRAME next_frame;
|
||
{
|
||
mips_extra_func_info_t proc_desc;
|
||
struct block *b = block_for_pc(pc);
|
||
struct symbol *sym;
|
||
CORE_ADDR startaddr;
|
||
|
||
find_pc_partial_function (pc, NULL, &startaddr, NULL);
|
||
if (b == NULL)
|
||
sym = NULL;
|
||
else
|
||
{
|
||
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. */
|
||
sym = NULL;
|
||
else
|
||
sym = lookup_symbol (MIPS_EFI_SYMBOL_NAME, b, LABEL_NAMESPACE,
|
||
0, NULL);
|
||
}
|
||
|
||
if (sym)
|
||
{
|
||
/* IF this is the topmost frame AND
|
||
* (this proc does not have debugging information OR
|
||
* the PC is in the procedure prologue)
|
||
* THEN create a "heuristic" proc_desc (by analyzing
|
||
* the actual code) to replace the "official" proc_desc.
|
||
*/
|
||
proc_desc = (mips_extra_func_info_t)SYMBOL_VALUE(sym);
|
||
if (next_frame == NULL) {
|
||
struct symtab_and_line val;
|
||
struct symbol *proc_symbol =
|
||
PROC_DESC_IS_DUMMY(proc_desc) ? 0 : PROC_SYMBOL(proc_desc);
|
||
|
||
if (proc_symbol) {
|
||
val = find_pc_line (BLOCK_START
|
||
(SYMBOL_BLOCK_VALUE(proc_symbol)),
|
||
0);
|
||
val.pc = val.end ? val.end : pc;
|
||
}
|
||
if (!proc_symbol || pc < val.pc) {
|
||
mips_extra_func_info_t found_heuristic =
|
||
heuristic_proc_desc(PROC_LOW_ADDR(proc_desc),
|
||
pc, next_frame);
|
||
if (found_heuristic) proc_desc = found_heuristic;
|
||
}
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* Is linked_proc_desc_table really necessary? It only seems to be used
|
||
by procedure call dummys. However, the procedures being called ought
|
||
to have their own proc_descs, and even if they don't,
|
||
heuristic_proc_desc knows how to create them! */
|
||
|
||
register struct linked_proc_info *link;
|
||
for (link = linked_proc_desc_table; link; link = link->next)
|
||
if (PROC_LOW_ADDR(&link->info) <= pc
|
||
&& PROC_HIGH_ADDR(&link->info) > pc)
|
||
return &link->info;
|
||
|
||
if (startaddr == 0)
|
||
startaddr = heuristic_proc_start (pc);
|
||
|
||
proc_desc =
|
||
heuristic_proc_desc (startaddr, pc, next_frame);
|
||
}
|
||
return proc_desc;
|
||
}
|
||
|
||
mips_extra_func_info_t cached_proc_desc;
|
||
|
||
FRAME_ADDR
|
||
mips_frame_chain(frame)
|
||
FRAME frame;
|
||
{
|
||
mips_extra_func_info_t proc_desc;
|
||
CORE_ADDR saved_pc = FRAME_SAVED_PC(frame);
|
||
|
||
if (saved_pc == 0 || inside_entry_file (saved_pc))
|
||
return 0;
|
||
|
||
proc_desc = find_proc_desc(saved_pc, frame);
|
||
if (!proc_desc)
|
||
return 0;
|
||
|
||
cached_proc_desc = proc_desc;
|
||
|
||
/* If no frame pointer and frame size is zero, we must be at end
|
||
of stack (or otherwise hosed). If we don't check frame size,
|
||
we loop forever if we see a zero size frame. */
|
||
if (PROC_FRAME_REG (proc_desc) == SP_REGNUM
|
||
&& PROC_FRAME_OFFSET (proc_desc) == 0
|
||
/* Frameless functions, which can happen on the innermost frame
|
||
or a frame which was innermost when a signal happened, can
|
||
have frame size zero. No need to check for non-frameless
|
||
functions in these situations, though (I don't think). */
|
||
&& frame->next != NULL
|
||
&& !frame->next->signal_handler_caller)
|
||
return 0;
|
||
else
|
||
return read_next_frame_reg(frame, PROC_FRAME_REG(proc_desc))
|
||
+ PROC_FRAME_OFFSET(proc_desc);
|
||
}
|
||
|
||
void
|
||
init_extra_frame_info(fci)
|
||
struct frame_info *fci;
|
||
{
|
||
extern struct obstack frame_cache_obstack;
|
||
/* Use proc_desc calculated in frame_chain */
|
||
mips_extra_func_info_t proc_desc =
|
||
fci->next ? cached_proc_desc : find_proc_desc(fci->pc, fci->next);
|
||
|
||
fci->saved_regs = (struct frame_saved_regs*)
|
||
obstack_alloc (&frame_cache_obstack, sizeof(struct frame_saved_regs));
|
||
memset (fci->saved_regs, 0, sizeof (struct frame_saved_regs));
|
||
fci->proc_desc =
|
||
proc_desc == &temp_proc_desc ? 0 : proc_desc;
|
||
if (proc_desc)
|
||
{
|
||
int ireg;
|
||
CORE_ADDR reg_position;
|
||
unsigned long mask;
|
||
/* r0 bit means kernel trap */
|
||
int kernel_trap = PROC_REG_MASK(proc_desc) & 1;
|
||
|
||
/* Fixup frame-pointer - only needed for top frame */
|
||
/* This may not be quite right, if proc has a real frame register */
|
||
if (fci->pc == PROC_LOW_ADDR(proc_desc) && !PROC_DESC_IS_DUMMY(proc_desc))
|
||
fci->frame = read_register (SP_REGNUM);
|
||
else
|
||
fci->frame = READ_FRAME_REG(fci, PROC_FRAME_REG(proc_desc))
|
||
+ PROC_FRAME_OFFSET(proc_desc);
|
||
|
||
/* If this is the innermost frame, and we are still in the
|
||
prologue (loosely defined), then the registers may not have
|
||
been saved yet. */
|
||
if (fci->next == NULL
|
||
&& !PROC_DESC_IS_DUMMY(proc_desc)
|
||
&& mips_in_lenient_prologue (PROC_LOW_ADDR (proc_desc), fci->pc))
|
||
{
|
||
/* Can't just say that the registers are not saved, because they
|
||
might get clobbered halfway through the prologue.
|
||
heuristic_proc_desc already has the right code to figure out
|
||
exactly what has been saved, so use it. As far as I know we
|
||
could be doing this (as we do on the 68k, for example)
|
||
regardless of whether we are in the prologue; I'm leaving in
|
||
the check for being in the prologue only out of conservatism
|
||
(I'm not sure whether heuristic_proc_desc handles all cases,
|
||
for example).
|
||
|
||
This stuff is ugly (and getting uglier by the minute). Probably
|
||
the best way to clean it up is to ignore the proc_desc's from
|
||
the symbols altogher, and get all the information we need by
|
||
examining the prologue (provided we can make the prologue
|
||
examining code good enough to get all the cases...). */
|
||
proc_desc =
|
||
heuristic_proc_desc (PROC_LOW_ADDR (proc_desc),
|
||
fci->pc,
|
||
fci->next);
|
||
}
|
||
|
||
if (proc_desc == &temp_proc_desc)
|
||
*fci->saved_regs = temp_saved_regs;
|
||
else
|
||
{
|
||
/* find which general-purpose registers were saved */
|
||
reg_position = fci->frame + PROC_REG_OFFSET(proc_desc);
|
||
mask = kernel_trap ? 0xFFFFFFFF : PROC_REG_MASK(proc_desc);
|
||
for (ireg= 31; mask; --ireg, mask <<= 1)
|
||
if (mask & 0x80000000)
|
||
{
|
||
fci->saved_regs->regs[ireg] = reg_position;
|
||
reg_position -= 4;
|
||
}
|
||
/* find which floating-point registers were saved */
|
||
reg_position = fci->frame + PROC_FREG_OFFSET(proc_desc);
|
||
|
||
/* The freg_offset points to where the first *double* register
|
||
is saved. So skip to the high-order word. */
|
||
reg_position += 4;
|
||
mask = kernel_trap ? 0xFFFFFFFF : PROC_FREG_MASK(proc_desc);
|
||
for (ireg = 31; mask; --ireg, mask <<= 1)
|
||
if (mask & 0x80000000)
|
||
{
|
||
fci->saved_regs->regs[FP0_REGNUM+ireg] = reg_position;
|
||
reg_position -= 4;
|
||
}
|
||
}
|
||
|
||
/* hack: if argument regs are saved, guess these contain args */
|
||
if ((PROC_REG_MASK(proc_desc) & 0xF0) == 0) fci->num_args = -1;
|
||
else if ((PROC_REG_MASK(proc_desc) & 0x80) == 0) fci->num_args = 4;
|
||
else if ((PROC_REG_MASK(proc_desc) & 0x40) == 0) fci->num_args = 3;
|
||
else if ((PROC_REG_MASK(proc_desc) & 0x20) == 0) fci->num_args = 2;
|
||
else if ((PROC_REG_MASK(proc_desc) & 0x10) == 0) fci->num_args = 1;
|
||
|
||
fci->saved_regs->regs[PC_REGNUM] = fci->saved_regs->regs[RA_REGNUM];
|
||
}
|
||
}
|
||
|
||
/* MIPS stack frames are almost impenetrable. When execution stops,
|
||
we basically have to look at symbol information for the function
|
||
that we stopped in, which tells us *which* register (if any) is
|
||
the base of the frame pointer, and what offset from that register
|
||
the frame itself is at.
|
||
|
||
This presents a problem when trying to examine a stack in memory
|
||
(that isn't executing at the moment), using the "frame" command. We
|
||
don't have a PC, nor do we have any registers except SP.
|
||
|
||
This routine takes two arguments, SP and PC, and tries to make the
|
||
cached frames look as if these two arguments defined a frame on the
|
||
cache. This allows the rest of info frame to extract the important
|
||
arguments without difficulty. */
|
||
|
||
FRAME
|
||
setup_arbitrary_frame (argc, argv)
|
||
int argc;
|
||
FRAME_ADDR *argv;
|
||
{
|
||
if (argc != 2)
|
||
error ("MIPS frame specifications require two arguments: sp and pc");
|
||
|
||
return create_new_frame (argv[0], argv[1]);
|
||
}
|
||
|
||
|
||
CORE_ADDR
|
||
mips_push_arguments(nargs, args, sp, struct_return, struct_addr)
|
||
int nargs;
|
||
value *args;
|
||
CORE_ADDR sp;
|
||
int struct_return;
|
||
CORE_ADDR struct_addr;
|
||
{
|
||
CORE_ADDR buf;
|
||
register i;
|
||
int accumulate_size = struct_return ? 4 : 0;
|
||
struct mips_arg { char *contents; int len; int offset; };
|
||
struct mips_arg *mips_args =
|
||
(struct mips_arg*)alloca(nargs * sizeof(struct mips_arg));
|
||
register struct mips_arg *m_arg;
|
||
for (i = 0, m_arg = mips_args; i < nargs; i++, m_arg++) {
|
||
extern value value_arg_coerce();
|
||
value arg = value_arg_coerce (args[i]);
|
||
m_arg->len = TYPE_LENGTH (VALUE_TYPE (arg));
|
||
/* This entire mips-specific routine is because doubles must be aligned
|
||
* on 8-byte boundaries. It still isn't quite right, because MIPS decided
|
||
* to align 'struct {int a, b}' on 4-byte boundaries (even though this
|
||
* breaks their varargs implementation...). A correct solution
|
||
* requires an simulation of gcc's 'alignof' (and use of 'alignof'
|
||
* in stdarg.h/varargs.h).
|
||
*/
|
||
if (m_arg->len > 4) accumulate_size = (accumulate_size + 7) & -8;
|
||
m_arg->offset = accumulate_size;
|
||
accumulate_size = (accumulate_size + m_arg->len + 3) & -4;
|
||
m_arg->contents = VALUE_CONTENTS(arg);
|
||
}
|
||
accumulate_size = (accumulate_size + 7) & (-8);
|
||
if (accumulate_size < 16) accumulate_size = 16;
|
||
sp -= accumulate_size;
|
||
for (i = nargs; m_arg--, --i >= 0; )
|
||
write_memory(sp + m_arg->offset, m_arg->contents, m_arg->len);
|
||
if (struct_return) {
|
||
buf = struct_addr;
|
||
write_memory(sp, (char *)&buf, sizeof(CORE_ADDR));
|
||
}
|
||
return sp;
|
||
}
|
||
|
||
/* MASK(i,j) == (1<<i) + (1<<(i+1)) + ... + (1<<j)). Assume i<=j<31. */
|
||
#define MASK(i,j) ((1 << (j)+1)-1 ^ (1 << (i))-1)
|
||
|
||
void
|
||
mips_push_dummy_frame()
|
||
{
|
||
int ireg;
|
||
struct linked_proc_info *link = (struct linked_proc_info*)
|
||
xmalloc(sizeof(struct linked_proc_info));
|
||
mips_extra_func_info_t proc_desc = &link->info;
|
||
CORE_ADDR sp = read_register (SP_REGNUM);
|
||
CORE_ADDR save_address;
|
||
REGISTER_TYPE buffer;
|
||
link->next = linked_proc_desc_table;
|
||
linked_proc_desc_table = link;
|
||
#define PUSH_FP_REGNUM 16 /* must be a register preserved across calls */
|
||
#define GEN_REG_SAVE_MASK MASK(1,16)|MASK(24,28)|(1<<31)
|
||
#define GEN_REG_SAVE_COUNT 22
|
||
#define FLOAT_REG_SAVE_MASK MASK(0,19)
|
||
#define FLOAT_REG_SAVE_COUNT 20
|
||
#define SPECIAL_REG_SAVE_COUNT 4
|
||
/*
|
||
* The registers we must save are all those not preserved across
|
||
* procedure calls. Dest_Reg (see tm-mips.h) must also be saved.
|
||
* In addition, we must save the PC, and PUSH_FP_REGNUM.
|
||
* (Ideally, we should also save MDLO/-HI and FP Control/Status reg.)
|
||
*
|
||
* Dummy frame layout:
|
||
* (high memory)
|
||
* Saved PC
|
||
* Saved MMHI, MMLO, FPC_CSR
|
||
* Saved R31
|
||
* Saved R28
|
||
* ...
|
||
* Saved R1
|
||
* Saved D18 (i.e. F19, F18)
|
||
* ...
|
||
* Saved D0 (i.e. F1, F0)
|
||
* CALL_DUMMY (subroutine stub; see tm-mips.h)
|
||
* Parameter build area (not yet implemented)
|
||
* (low memory)
|
||
*/
|
||
PROC_REG_MASK(proc_desc) = GEN_REG_SAVE_MASK;
|
||
PROC_FREG_MASK(proc_desc) = mips_fpu ? FLOAT_REG_SAVE_MASK : 0;
|
||
PROC_REG_OFFSET(proc_desc) = /* offset of (Saved R31) from FP */
|
||
-sizeof(long) - 4 * SPECIAL_REG_SAVE_COUNT;
|
||
PROC_FREG_OFFSET(proc_desc) = /* offset of (Saved D18) from FP */
|
||
-sizeof(double) - 4 * (SPECIAL_REG_SAVE_COUNT + GEN_REG_SAVE_COUNT);
|
||
/* save general registers */
|
||
save_address = sp + PROC_REG_OFFSET(proc_desc);
|
||
for (ireg = 32; --ireg >= 0; )
|
||
if (PROC_REG_MASK(proc_desc) & (1 << ireg))
|
||
{
|
||
buffer = read_register (ireg);
|
||
write_memory (save_address, (char *)&buffer, sizeof(REGISTER_TYPE));
|
||
save_address -= 4;
|
||
}
|
||
/* save floating-points registers starting with high order word */
|
||
save_address = sp + PROC_FREG_OFFSET(proc_desc) + 4;
|
||
for (ireg = 32; --ireg >= 0; )
|
||
if (PROC_FREG_MASK(proc_desc) & (1 << ireg))
|
||
{
|
||
buffer = read_register (ireg + FP0_REGNUM);
|
||
write_memory (save_address, (char *)&buffer, 4);
|
||
save_address -= 4;
|
||
}
|
||
write_register (PUSH_FP_REGNUM, sp);
|
||
PROC_FRAME_REG(proc_desc) = PUSH_FP_REGNUM;
|
||
PROC_FRAME_OFFSET(proc_desc) = 0;
|
||
buffer = read_register (PC_REGNUM);
|
||
write_memory (sp - 4, (char *)&buffer, sizeof(REGISTER_TYPE));
|
||
buffer = read_register (HI_REGNUM);
|
||
write_memory (sp - 8, (char *)&buffer, sizeof(REGISTER_TYPE));
|
||
buffer = read_register (LO_REGNUM);
|
||
write_memory (sp - 12, (char *)&buffer, sizeof(REGISTER_TYPE));
|
||
buffer = read_register (mips_fpu ? FCRCS_REGNUM : ZERO_REGNUM);
|
||
write_memory (sp - 16, (char *)&buffer, sizeof(REGISTER_TYPE));
|
||
sp -= 4 * (GEN_REG_SAVE_COUNT
|
||
+ (mips_fpu ? FLOAT_REG_SAVE_COUNT : 0)
|
||
+ SPECIAL_REG_SAVE_COUNT);
|
||
write_register (SP_REGNUM, sp);
|
||
PROC_LOW_ADDR(proc_desc) = sp - CALL_DUMMY_SIZE + CALL_DUMMY_START_OFFSET;
|
||
PROC_HIGH_ADDR(proc_desc) = sp;
|
||
SET_PROC_DESC_IS_DUMMY(proc_desc);
|
||
PROC_PC_REG(proc_desc) = RA_REGNUM;
|
||
}
|
||
|
||
void
|
||
mips_pop_frame()
|
||
{
|
||
register int regnum;
|
||
FRAME frame = get_current_frame ();
|
||
CORE_ADDR new_sp = frame->frame;
|
||
|
||
mips_extra_func_info_t proc_desc = frame->proc_desc;
|
||
|
||
write_register (PC_REGNUM, FRAME_SAVED_PC(frame));
|
||
if (proc_desc)
|
||
{
|
||
for (regnum = 32; --regnum >= 0; )
|
||
if (PROC_REG_MASK(proc_desc) & (1 << regnum))
|
||
write_register (regnum,
|
||
read_memory_integer (frame->saved_regs->regs[regnum],
|
||
4));
|
||
for (regnum = 32; --regnum >= 0; )
|
||
if (PROC_FREG_MASK(proc_desc) & (1 << regnum))
|
||
write_register (regnum + FP0_REGNUM,
|
||
read_memory_integer (frame->saved_regs->regs[regnum + FP0_REGNUM], 4));
|
||
}
|
||
write_register (SP_REGNUM, new_sp);
|
||
flush_cached_frames ();
|
||
/* We let mips_init_extra_frame_info figure out the frame pointer */
|
||
set_current_frame (create_new_frame (0, read_pc ()));
|
||
|
||
if (PROC_DESC_IS_DUMMY(proc_desc))
|
||
{
|
||
struct linked_proc_info *pi_ptr, *prev_ptr;
|
||
|
||
for (pi_ptr = linked_proc_desc_table, prev_ptr = NULL;
|
||
pi_ptr != NULL;
|
||
prev_ptr = pi_ptr, pi_ptr = pi_ptr->next)
|
||
{
|
||
if (&pi_ptr->info == proc_desc)
|
||
break;
|
||
}
|
||
|
||
if (pi_ptr == NULL)
|
||
error ("Can't locate dummy extra frame info\n");
|
||
|
||
if (prev_ptr != NULL)
|
||
prev_ptr->next = pi_ptr->next;
|
||
else
|
||
linked_proc_desc_table = pi_ptr->next;
|
||
|
||
free (pi_ptr);
|
||
|
||
write_register (HI_REGNUM, read_memory_integer(new_sp - 8, 4));
|
||
write_register (LO_REGNUM, read_memory_integer(new_sp - 12, 4));
|
||
if (mips_fpu)
|
||
write_register (FCRCS_REGNUM, read_memory_integer(new_sp - 16, 4));
|
||
}
|
||
}
|
||
|
||
static void
|
||
mips_print_register (regnum, all)
|
||
int regnum, all;
|
||
{
|
||
unsigned char raw_buffer[MAX_REGISTER_RAW_SIZE];
|
||
REGISTER_TYPE val;
|
||
|
||
/* Get the data in raw format. */
|
||
if (read_relative_register_raw_bytes (regnum, raw_buffer))
|
||
{
|
||
printf_filtered ("%s: [Invalid]", reg_names[regnum]);
|
||
return;
|
||
}
|
||
|
||
/* If an even floating pointer register, also print as double. */
|
||
if (regnum >= FP0_REGNUM && regnum < FP0_REGNUM+32
|
||
&& !((regnum-FP0_REGNUM) & 1)) {
|
||
char dbuffer[MAX_REGISTER_RAW_SIZE];
|
||
|
||
read_relative_register_raw_bytes (regnum, dbuffer);
|
||
read_relative_register_raw_bytes (regnum+1, dbuffer+4);
|
||
#ifdef REGISTER_CONVERT_TO_TYPE
|
||
REGISTER_CONVERT_TO_TYPE(regnum, builtin_type_double, dbuffer);
|
||
#endif
|
||
printf_filtered ("(d%d: ", regnum-FP0_REGNUM);
|
||
val_print (builtin_type_double, dbuffer, 0,
|
||
stdout, 0, 1, 0, Val_pretty_default);
|
||
printf_filtered ("); ");
|
||
}
|
||
fputs_filtered (reg_names[regnum], stdout);
|
||
|
||
/* The problem with printing numeric register names (r26, etc.) is that
|
||
the user can't use them on input. Probably the best solution is to
|
||
fix it so that either the numeric or the funky (a2, etc.) names
|
||
are accepted on input. */
|
||
if (regnum < 32)
|
||
printf_filtered ("(r%d): ", regnum);
|
||
else
|
||
printf_filtered (": ");
|
||
|
||
/* If virtual format is floating, print it that way. */
|
||
if (TYPE_CODE (REGISTER_VIRTUAL_TYPE (regnum)) == TYPE_CODE_FLT
|
||
&& ! INVALID_FLOAT (raw_buffer, REGISTER_VIRTUAL_SIZE(regnum))) {
|
||
val_print (REGISTER_VIRTUAL_TYPE (regnum), raw_buffer, 0,
|
||
stdout, 0, 1, 0, Val_pretty_default);
|
||
}
|
||
/* Else print as integer in hex. */
|
||
else
|
||
{
|
||
long val;
|
||
|
||
val = extract_signed_integer (raw_buffer,
|
||
REGISTER_RAW_SIZE (regnum));
|
||
|
||
if (val == 0)
|
||
printf_filtered ("0");
|
||
else if (all)
|
||
/* FIXME: We should be printing this in a fixed field width, so that
|
||
registers line up. */
|
||
printf_filtered (local_hex_format(), val);
|
||
else
|
||
printf_filtered ("%s=%d", local_hex_string(val), val);
|
||
}
|
||
}
|
||
|
||
/* Replacement for generic do_registers_info. */
|
||
void
|
||
mips_do_registers_info (regnum, fpregs)
|
||
int regnum;
|
||
int fpregs;
|
||
{
|
||
if (regnum != -1) {
|
||
mips_print_register (regnum, 0);
|
||
printf_filtered ("\n");
|
||
}
|
||
else {
|
||
for (regnum = 0; regnum < NUM_REGS; ) {
|
||
if ((!fpregs) && regnum >= FP0_REGNUM && regnum <= FCRIR_REGNUM) {
|
||
regnum++;
|
||
continue;
|
||
}
|
||
mips_print_register (regnum, 1);
|
||
regnum++;
|
||
if ((regnum & 3) == 0 || regnum == NUM_REGS)
|
||
printf_filtered (";\n");
|
||
else
|
||
printf_filtered ("; ");
|
||
}
|
||
}
|
||
}
|
||
/* Return number of args passed to a frame. described by FIP.
|
||
Can return -1, meaning no way to tell. */
|
||
|
||
int
|
||
mips_frame_num_args(fip)
|
||
FRAME fip;
|
||
{
|
||
#if 0
|
||
struct chain_info_t *p;
|
||
|
||
p = mips_find_cached_frame(FRAME_FP(fip));
|
||
if (p->valid)
|
||
return p->the_info.numargs;
|
||
#endif
|
||
return -1;
|
||
}
|
||
|
||
/* Is this a branch with a delay slot? */
|
||
static int
|
||
is_delayed (insn)
|
||
unsigned long insn;
|
||
{
|
||
int i;
|
||
for (i = 0; i < NUMOPCODES; ++i)
|
||
if (mips_opcodes[i].pinfo != INSN_MACRO
|
||
&& (insn & mips_opcodes[i].mask) == mips_opcodes[i].match)
|
||
break;
|
||
return (i < NUMOPCODES
|
||
&& (mips_opcodes[i].pinfo & (INSN_UNCOND_BRANCH_DELAY
|
||
| INSN_COND_BRANCH_DELAY
|
||
| INSN_COND_BRANCH_LIKELY)));
|
||
}
|
||
|
||
/* To skip prologues, I use this predicate. Returns either PC itself
|
||
if the code at PC does not look like a function prologue; otherwise
|
||
returns an address that (if we're lucky) follows the prologue. If
|
||
LENIENT, then we must skip everything which is involved in setting
|
||
up the frame (it's OK to skip more, just so long as we don't skip
|
||
anything which might clobber the registers which are being saved.
|
||
We must skip more in the case where part of the prologue is in the
|
||
delay slot of a non-prologue instruction). */
|
||
|
||
CORE_ADDR
|
||
mips_skip_prologue (pc, lenient)
|
||
CORE_ADDR pc;
|
||
int lenient;
|
||
{
|
||
struct symbol *f;
|
||
struct block *b;
|
||
unsigned long inst;
|
||
int offset;
|
||
int seen_sp_adjust = 0;
|
||
|
||
/* Skip the typical prologue instructions. These are the stack adjustment
|
||
instruction and the instructions that save registers on the stack
|
||
or in the gcc frame. */
|
||
for (offset = 0; offset < 100; offset += 4)
|
||
{
|
||
char buf[4];
|
||
int status;
|
||
|
||
status = read_memory_nobpt (pc + offset, buf, 4);
|
||
if (status)
|
||
memory_error (status, pc + offset);
|
||
inst = extract_unsigned_integer (buf, 4);
|
||
|
||
if (lenient && is_delayed (inst))
|
||
continue;
|
||
|
||
if ((inst & 0xffff0000) == 0x27bd0000) /* addiu $sp,$sp,offset */
|
||
seen_sp_adjust = 1;
|
||
else if ((inst & 0xFFE00000) == 0xAFA00000 && (inst & 0x001F0000))
|
||
continue; /* sw reg,n($sp) */
|
||
/* reg != $zero */
|
||
else if ((inst & 0xFFE00000) == 0xE7A00000) /* swc1 freg,n($sp) */
|
||
continue;
|
||
else if ((inst & 0xF3E00000) == 0xA3C00000 && (inst & 0x001F0000))
|
||
/* sx reg,n($s8) */
|
||
continue; /* reg != $zero */
|
||
else if (inst == 0x03A0F021) /* move $s8,$sp */
|
||
continue;
|
||
else if ((inst & 0xFF9F07FF) == 0x00800021) /* move reg,$a0-$a3 */
|
||
continue;
|
||
else
|
||
break;
|
||
}
|
||
return pc + offset;
|
||
|
||
/* FIXME schauer. The following code seems no longer necessary if we
|
||
always skip the typical prologue instructions. */
|
||
|
||
#if 0
|
||
if (seen_sp_adjust)
|
||
return pc + offset;
|
||
|
||
/* Well, it looks like a frameless. Let's make sure.
|
||
Note that we are not called on the current PC,
|
||
but on the function`s start PC, and I have definitely
|
||
seen optimized code that adjusts the SP quite later */
|
||
b = block_for_pc(pc);
|
||
if (!b) return pc;
|
||
|
||
f = lookup_symbol(MIPS_EFI_SYMBOL_NAME, b, LABEL_NAMESPACE, 0, NULL);
|
||
if (!f) return pc;
|
||
/* Ideally, I would like to use the adjusted info
|
||
from mips_frame_info(), but for all practical
|
||
purposes it will not matter (and it would require
|
||
a different definition of SKIP_PROLOGUE())
|
||
|
||
Actually, it would not hurt to skip the storing
|
||
of arguments on the stack as well. */
|
||
if (((mips_extra_func_info_t)SYMBOL_VALUE(f))->pdr.frameoffset)
|
||
return pc + 4;
|
||
|
||
return pc;
|
||
#endif
|
||
}
|
||
|
||
/* Is address PC in the prologue (loosely defined) for function at
|
||
STARTADDR? */
|
||
|
||
static int
|
||
mips_in_lenient_prologue (startaddr, pc)
|
||
CORE_ADDR startaddr;
|
||
CORE_ADDR pc;
|
||
{
|
||
CORE_ADDR end_prologue = mips_skip_prologue (startaddr, 1);
|
||
return pc >= startaddr && pc < end_prologue;
|
||
}
|
||
|
||
/* Given a return value in `regbuf' with a type `valtype',
|
||
extract and copy its value into `valbuf'. */
|
||
void
|
||
mips_extract_return_value (valtype, regbuf, valbuf)
|
||
struct type *valtype;
|
||
char regbuf[REGISTER_BYTES];
|
||
char *valbuf;
|
||
{
|
||
int regnum;
|
||
|
||
regnum = TYPE_CODE (valtype) == TYPE_CODE_FLT && mips_fpu ? FP0_REGNUM : 2;
|
||
|
||
memcpy (valbuf, regbuf + REGISTER_BYTE (regnum), TYPE_LENGTH (valtype));
|
||
#ifdef REGISTER_CONVERT_TO_TYPE
|
||
REGISTER_CONVERT_TO_TYPE(regnum, valtype, valbuf);
|
||
#endif
|
||
}
|
||
|
||
/* Given a return value in `regbuf' with a type `valtype',
|
||
write it's value into the appropriate register. */
|
||
void
|
||
mips_store_return_value (valtype, valbuf)
|
||
struct type *valtype;
|
||
char *valbuf;
|
||
{
|
||
int regnum;
|
||
char raw_buffer[MAX_REGISTER_RAW_SIZE];
|
||
|
||
regnum = TYPE_CODE (valtype) == TYPE_CODE_FLT && mips_fpu ? FP0_REGNUM : 2;
|
||
memcpy(raw_buffer, valbuf, TYPE_LENGTH (valtype));
|
||
|
||
#ifdef REGISTER_CONVERT_FROM_TYPE
|
||
REGISTER_CONVERT_FROM_TYPE(regnum, valtype, raw_buffer);
|
||
#endif
|
||
|
||
write_register_bytes(REGISTER_BYTE (regnum), raw_buffer, TYPE_LENGTH (valtype));
|
||
}
|
||
|
||
static void reinit_frame_cache_sfunc PARAMS ((char *, int,
|
||
struct cmd_list_element *));
|
||
|
||
/* Just like reinit_frame_cache, but with the right arguments to be
|
||
callable as an sfunc. */
|
||
static void
|
||
reinit_frame_cache_sfunc (args, from_tty, c)
|
||
char *args;
|
||
int from_tty;
|
||
struct cmd_list_element *c;
|
||
{
|
||
reinit_frame_cache ();
|
||
}
|
||
|
||
void
|
||
_initialize_mips_tdep ()
|
||
{
|
||
struct cmd_list_element *c;
|
||
|
||
/* Let the user turn off floating point and set the fence post for
|
||
heuristic_proc_start. */
|
||
|
||
add_show_from_set
|
||
(add_set_cmd ("mipsfpu", class_support, var_boolean,
|
||
(char *) &mips_fpu,
|
||
"Set use of floating point coprocessor.\n\
|
||
Turn off to avoid using floating point instructions when calling functions\n\
|
||
or dealing with return values.", &setlist),
|
||
&showlist);
|
||
|
||
/* We really would like to have both "0" and "unlimited" work, but
|
||
command.c doesn't deal with that. So make it a var_zinteger
|
||
because the user can always use "999999" or some such for unlimited. */
|
||
c = add_set_cmd ("heuristic-fence-post", class_support, var_zinteger,
|
||
(char *) &heuristic_fence_post,
|
||
"\
|
||
Set the distance searched for the start of a function.\n\
|
||
If you are debugging a stripped executable, GDB needs to search through the\n\
|
||
program for the start of a function. This command sets the distance of the\n\
|
||
search. The only need to set it is when debugging a stripped executable.",
|
||
&setlist);
|
||
/* We need to throw away the frame cache when we set this, since it
|
||
might change our ability to get backtraces. */
|
||
c->function.sfunc = reinit_frame_cache_sfunc;
|
||
add_show_from_set (c, &showlist);
|
||
}
|