char *
frag_var (relax_stateT type, int max_chars, int var, relax_substateT subtype,
symbolS *symbol, offsetT offset, char *opcode)
{
register char *retval;
frag_grow (max_chars);
retval = obstack_next_free (&frchain_now->frch_obstack);
obstack_blank_fast (&frchain_now->frch_obstack, max_chars);
frag_now->fr_var = var;
frag_now->fr_type = type;
frag_now->fr_subtype = subtype;
frag_now->fr_symbol = symbol;
frag_now->fr_offset = offset;
frag_now->fr_opcode = opcode;
#ifdef USING_CGEN
frag_now->fr_cgen.insn = 0;
frag_now->fr_cgen.opindex = 0;
frag_now->fr_cgen.opinfo = 0;
#endif
#ifdef TC_FRAG_INIT
TC_FRAG_INIT (frag_now);
#endif
as_where (&frag_now->fr_file, &frag_now->fr_line);
frag_new (max_chars);
return (retval);
}
char *
frag_more (int nchars)
{
register char *retval;
frag_alloc_check (&frchain_now->frch_obstack);
frag_grow (nchars);
retval = obstack_next_free (&frchain_now->frch_obstack);
obstack_blank_fast (&frchain_now->frch_obstack, nchars);
return (retval);
}
/*
* frag_more()
*
* Start a new frag unless we have n more chars of room in the current frag.
* Close off the old frag with a .fill 0.
*
* Return the address of the 1st char to write into. Advance
* frag_now_growth past the new chars.
*/
char *
frag_more(
int nchars)
{
register char *retval;
frag_grow (nchars);
retval = obstack_next_free (&frags);
obstack_blank_fast (&frags, nchars);
return (retval);
} /* frag_more() */
char *
frag_var (relax_stateT type, int max_chars, int var, relax_substateT subtype,
symbolS *symbol, offsetT offset, char *opcode)
{
register char *retval;
frag_grow (max_chars);
retval = obstack_next_free (&frchain_now->frch_obstack);
obstack_blank_fast (&frchain_now->frch_obstack, max_chars);
frag_var_init (type, max_chars, var, subtype, symbol, offset, opcode);
return retval;
}
/*
* frag_var()
*
* Start a new frag unless we have max_chars more chars of room in the current frag.
* Close off the old frag with a .fill 0.
*
* Set up a machine_dependent relaxable frag, then start a new frag.
* Return the address of the 1st char of the var part of the old frag
* to write into.
*/
char *
frag_var(
relax_stateT type,
int max_chars,
int var,
relax_substateT subtype,
symbolS *symbol,
long offset,
char *opcode)
{
register char *retval;
frag_grow (max_chars);
retval = obstack_next_free (&frags);
obstack_blank_fast (&frags, max_chars);
frag_now->fr_var = var;
frag_now->fr_type = type;
frag_now->fr_subtype = subtype;
frag_now->fr_symbol = symbol;
frag_now->fr_offset = offset;
frag_now->fr_opcode = opcode;
frag_new (max_chars);
return (retval);
} /* frag_var() */
int
check_eh_frame (expressionS *exp, unsigned int *pnbytes)
{
struct frame_data
{
enum frame_state state;
int cie_info_ok;
struct cie_info cie_info;
symbolS *size_end_sym;
fragS *loc4_frag;
int loc4_fix;
int aug_size;
int aug_shift;
};
static struct frame_data eh_frame_data;
static struct frame_data debug_frame_data;
struct frame_data *d;
/* Don't optimize. */
if (flag_traditional_format)
return 0;
#ifdef md_allow_eh_opt
if (! md_allow_eh_opt)
return 0;
#endif
/* Select the proper section data. */
if (strncmp (segment_name (now_seg), ".eh_frame", 9) == 0
&& segment_name (now_seg)[9] != '_')
d = &eh_frame_data;
else if (strncmp (segment_name (now_seg), ".debug_frame", 12) == 0)
d = &debug_frame_data;
else
return 0;
if (d->state >= state_saw_size && S_IS_DEFINED (d->size_end_sym))
{
/* We have come to the end of the CIE or FDE. See below where
we set saw_size. We must check this first because we may now
be looking at the next size. */
d->state = state_idle;
}
switch (d->state)
{
case state_idle:
if (*pnbytes == 4)
{
/* This might be the size of the CIE or FDE. We want to know
the size so that we don't accidentally optimize across an FDE
boundary. We recognize the size in one of two forms: a
symbol which will later be defined as a difference, or a
subtraction of two symbols. Either way, we can tell when we
are at the end of the FDE because the symbol becomes defined
(in the case of a subtraction, the end symbol, from which the
start symbol is being subtracted). Other ways of describing
the size will not be optimized. */
if ((exp->X_op == O_symbol || exp->X_op == O_subtract)
&& ! S_IS_DEFINED (exp->X_add_symbol))
{
d->state = state_saw_size;
d->size_end_sym = exp->X_add_symbol;
}
}
break;
case state_saw_size:
case state_saw_cie_offset:
/* Assume whatever form it appears in, it appears atomically. */
d->state = (enum frame_state) (d->state + 1);
break;
case state_saw_pc_begin:
/* Decide whether we should see an augmentation. */
if (! d->cie_info_ok
&& ! (d->cie_info_ok = get_cie_info (&d->cie_info)))
d->state = state_error;
else if (d->cie_info.z_augmentation)
{
d->state = state_seeing_aug_size;
d->aug_size = 0;
d->aug_shift = 0;
}
else
d->state = state_wait_loc4;
break;
case state_seeing_aug_size:
/* Bytes == -1 means this comes from an leb128 directive. */
if ((int)*pnbytes == -1 && exp->X_op == O_constant)
{
d->aug_size = exp->X_add_number;
d->state = state_skipping_aug;
}
else if (*pnbytes == 1 && exp->X_op == O_constant)
{
unsigned char byte = exp->X_add_number;
d->aug_size |= (byte & 0x7f) << d->aug_shift;
d->aug_shift += 7;
if ((byte & 0x80) == 0)
d->state = state_skipping_aug;
}
else
d->state = state_error;
if (d->state == state_skipping_aug && d->aug_size == 0)
d->state = state_wait_loc4;
break;
case state_skipping_aug:
if ((int)*pnbytes < 0)
d->state = state_error;
else
{
int left = (d->aug_size -= *pnbytes);
if (left == 0)
d->state = state_wait_loc4;
else if (left < 0)
d->state = state_error;
}
break;
case state_wait_loc4:
if (*pnbytes == 1
&& exp->X_op == O_constant
&& exp->X_add_number == DW_CFA_advance_loc4)
{
/* This might be a DW_CFA_advance_loc4. Record the frag and the
position within the frag, so that we can change it later. */
frag_grow (1);
d->state = state_saw_loc4;
d->loc4_frag = frag_now;
d->loc4_fix = frag_now_fix ();
}
break;
case state_saw_loc4:
d->state = state_wait_loc4;
if (*pnbytes != 4)
break;
if (exp->X_op == O_constant)
{
/* This is a case which we can optimize. The two symbols being
subtracted were in the same frag and the expression was
reduced to a constant. We can do the optimization entirely
in this function. */
if (exp->X_add_number < 0x40)
{
d->loc4_frag->fr_literal[d->loc4_fix]
= DW_CFA_advance_loc | exp->X_add_number;
/* No more bytes needed. */
return 1;
}
else if (exp->X_add_number < 0x100)
{
d->loc4_frag->fr_literal[d->loc4_fix] = DW_CFA_advance_loc1;
*pnbytes = 1;
}
else if (exp->X_add_number < 0x10000)
{
d->loc4_frag->fr_literal[d->loc4_fix] = DW_CFA_advance_loc2;
*pnbytes = 2;
}
}
else if (exp->X_op == O_subtract && d->cie_info.code_alignment == 1)
{
/* This is a case we can optimize. The expression was not
reduced, so we can not finish the optimization until the end
of the assembly. We set up a variant frag which we handle
later. */
frag_var (rs_cfa, 4, 0, 1 << 3, make_expr_symbol (exp),
d->loc4_fix, (char *) d->loc4_frag);
return 1;
}
else if ((exp->X_op == O_divide
|| exp->X_op == O_right_shift)
&& d->cie_info.code_alignment > 1)
{
if (symbol_symbolS (exp->X_add_symbol)
&& symbol_constant_p (exp->X_op_symbol)
&& S_GET_SEGMENT (exp->X_op_symbol) == absolute_section
&& ((exp->X_op == O_divide
? *symbol_X_add_number (exp->X_op_symbol)
: (offsetT) 1 << *symbol_X_add_number (exp->X_op_symbol))
== (offsetT) d->cie_info.code_alignment))
{
expressionS *symval;
symval = symbol_get_value_expression (exp->X_add_symbol);
if (symval->X_op == O_subtract)
{
/* This is a case we can optimize as well. The
expression was not reduced, so we can not finish
the optimization until the end of the assembly.
We set up a variant frag which we handle later. */
frag_var (rs_cfa, 4, 0, d->cie_info.code_alignment << 3,
make_expr_symbol (symval),
d->loc4_fix, (char *) d->loc4_frag);
return 1;
}
}
}
break;
case state_error:
/* Just skipping everything. */
break;
}
return 0;
}
