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dwarf2cfi: Handle return column save from CIE. 

When we record a save of the return column in the CIE, remember
that while processing the FDE.  This requires propagating the
handling of PC_RTX as a representative of the return column to
more locations.

MIPS had been handling this case by hand, and is no longer required.

        * dwarf2cfi.c (cie_return_save): New.
        (queue_reg_save): Use compare_reg_or_pc.
        (dwarf2out_flush_queued_reg_saves): Handle pc_rtx as return column.
        (dwarf2out_frame_debug_expr): Likewise.
        (dwarf2out_frame_debug_cfa_register): Record saved reg for pc too.
        (initial_return_save): Likewise.
        (execute_dwarf2_frame): Save and restore initial return save from
        the cie to the fde.
        * config/mips/mips.c (mips_frame_set): Remove special case for
        DWARF_FRAME_RETURN_COLUMN.

From-SVN: r176099
This commit is contained in:
Richard Henderson 2011-07-09 13:39:00 -07:00 committed by Richard Henderson
parent 4a8ee12241
commit a8e5c0e77e
3 changed files with 139 additions and 103 deletions
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13
gcc/ChangeLog
View File

@ -1,3 +1,16 @@
2011-07-09 Richard Henderson <rth@redhat.com>
* dwarf2cfi.c (cie_return_save): New.
(queue_reg_save): Use compare_reg_or_pc.
(dwarf2out_flush_queued_reg_saves): Handle pc_rtx as return column.
(dwarf2out_frame_debug_expr): Likewise.
(dwarf2out_frame_debug_cfa_register): Record saved reg for pc too.
(initial_return_save): Likewise.
(execute_dwarf2_frame): Save and restore initial return save from
the cie to the fde.
* config/mips/mips.c (mips_frame_set): Remove special case for
DWARF_FRAME_RETURN_COLUMN.
2011-07-09 Richard Henderson <rth@redhat.com>
* dwarf2cfi.c (lookup_cfa): Remove.

7
gcc/config/mips/mips.c
View File

@ -8203,13 +8203,6 @@ mips_frame_set (rtx mem, rtx reg)
{
rtx set;
/* If we're saving the return address register and the DWARF return
address column differs from the hard register number, adjust the
note reg to refer to the former. */
if (REGNO (reg) == RETURN_ADDR_REGNUM
&& DWARF_FRAME_RETURN_COLUMN != RETURN_ADDR_REGNUM)
reg = gen_rtx_REG (GET_MODE (reg), DWARF_FRAME_RETURN_COLUMN);
set = gen_rtx_SET (VOIDmode, mem, reg);
RTX_FRAME_RELATED_P (set) = 1;

222
gcc/dwarf2cfi.c
View File

@ -603,64 +603,6 @@ reg_save (unsigned int reg, unsigned int sreg, HOST_WIDE_INT offset)
add_cfi (cfi);
}
/* Record the initial position of the return address. RTL is
INCOMING_RETURN_ADDR_RTX. */
static void
initial_return_save (rtx rtl)
{
unsigned int reg = INVALID_REGNUM;
HOST_WIDE_INT offset = 0;
switch (GET_CODE (rtl))
{
case REG:
/* RA is in a register. */
reg = DWARF_FRAME_REGNUM (REGNO (rtl));
break;
case MEM:
/* RA is on the stack. */
rtl = XEXP (rtl, 0);
switch (GET_CODE (rtl))
{
case REG:
gcc_assert (REGNO (rtl) == STACK_POINTER_REGNUM);
offset = 0;
break;
case PLUS:
gcc_assert (REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM);
offset = INTVAL (XEXP (rtl, 1));
break;
case MINUS:
gcc_assert (REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM);
offset = -INTVAL (XEXP (rtl, 1));
break;
default:
gcc_unreachable ();
}
break;
case PLUS:
/* The return address is at some offset from any value we can
actually load. For instance, on the SPARC it is in %i7+8. Just
ignore the offset for now; it doesn't matter for unwinding frames. */
gcc_assert (CONST_INT_P (XEXP (rtl, 1)));
initial_return_save (XEXP (rtl, 0));
return;
default:
gcc_unreachable ();
}
if (reg != DWARF_FRAME_RETURN_COLUMN)
reg_save (DWARF_FRAME_RETURN_COLUMN, reg, offset - cfa.offset);
}
/* Given a SET, calculate the amount of stack adjustment it
contains. */
@ -1088,6 +1030,8 @@ DEF_VEC_ALLOC_O (reg_saved_in_data, gc);
5 entries. */
static GTY(()) VEC(reg_saved_in_data, gc) *regs_saved_in_regs;
static GTY(()) reg_saved_in_data *cie_return_save;
/* Compare X and Y for equivalence. The inputs may be REGs or PC_RTX. */
static bool
@ -1134,10 +1078,9 @@ queue_reg_save (rtx reg, rtx sreg, HOST_WIDE_INT offset)
struct queued_reg_save *q;
/* Duplicates waste space, but it's also necessary to remove them
for correctness, since the queue gets output in reverse
order. */
for correctness, since the queue gets output in reverse order. */
for (q = queued_reg_saves; q != NULL; q = q->next)
if (REGNO (q->reg) == REGNO (reg))
if (compare_reg_or_pc (q->reg, reg))
break;
if (q == NULL)
@ -1165,7 +1108,10 @@ dwarf2out_flush_queued_reg_saves (void)
record_reg_saved_in_reg (q->saved_reg, q->reg);
reg = DWARF_FRAME_REGNUM (REGNO (q->reg));
if (q->reg == pc_rtx)
reg = DWARF_FRAME_RETURN_COLUMN;
else
reg = DWARF_FRAME_REGNUM (REGNO (q->reg));
if (q->saved_reg)
sreg = DWARF_FRAME_REGNUM (REGNO (q->saved_reg));
else
@ -1375,13 +1321,11 @@ dwarf2out_frame_debug_cfa_register (rtx set)
src = XEXP (set, 1);
dest = XEXP (set, 0);
record_reg_saved_in_reg (dest, src);
if (src == pc_rtx)
sregno = DWARF_FRAME_RETURN_COLUMN;
else
{
record_reg_saved_in_reg (dest, src);
sregno = DWARF_FRAME_REGNUM (REGNO (src));
}
sregno = DWARF_FRAME_REGNUM (REGNO (src));
dregno = DWARF_FRAME_REGNUM (REGNO (dest));
@ -2031,14 +1975,14 @@ dwarf2out_frame_debug_expr (rtx expr)
gcc_unreachable ();
}
/* Rule 17 */
/* If the source operand of this MEM operation is not a
register, basically the source is return address. Here
we only care how much stack grew and we don't save it. */
if (!REG_P (src))
/* Rule 17 */
/* If the source operand of this MEM operation is a memory,
we only care how much stack grew. */
if (MEM_P (src))
break;
if (REGNO (src) != STACK_POINTER_REGNUM
if (REG_P (src)
&& REGNO (src) != STACK_POINTER_REGNUM
&& REGNO (src) != HARD_FRAME_POINTER_REGNUM
&& (unsigned) REGNO (src) == cfa.reg)
{
@ -2098,32 +2042,30 @@ dwarf2out_frame_debug_expr (rtx expr)
}
def_cfa_1 (&cfa);
{
span = NULL;
if (REG_P (src))
span = targetm.dwarf_register_span (src);
if (!span)
queue_reg_save (src, NULL_RTX, offset);
else
{
/* We have a PARALLEL describing where the contents of SRC live.
Queue register saves for each piece of the PARALLEL. */
int par_index;
int limit;
HOST_WIDE_INT span_offset = offset;
if (!span)
queue_reg_save (src, NULL_RTX, offset);
else
{
/* We have a PARALLEL describing where the contents of SRC
live. Queue register saves for each piece of the
PARALLEL. */
int par_index;
int limit;
HOST_WIDE_INT span_offset = offset;
gcc_assert (GET_CODE (span) == PARALLEL);
gcc_assert (GET_CODE (span) == PARALLEL);
limit = XVECLEN (span, 0);
for (par_index = 0; par_index < limit; par_index++)
{
rtx elem = XVECEXP (span, 0, par_index);
queue_reg_save (elem, NULL_RTX, span_offset);
span_offset += GET_MODE_SIZE (GET_MODE (elem));
}
}
}
limit = XVECLEN (span, 0);
for (par_index = 0; par_index < limit; par_index++)
{
rtx elem = XVECEXP (span, 0, par_index);
queue_reg_save (elem, NULL_RTX, span_offset);
span_offset += GET_MODE_SIZE (GET_MODE (elem));
}
}
break;
default:
@ -2543,6 +2485,67 @@ dwarf2out_frame_debug_restore_state (void)
cfa_remember.in_use = 0;
}
/* Record the initial position of the return address. RTL is
INCOMING_RETURN_ADDR_RTX. */
static void
initial_return_save (rtx rtl)
{
unsigned int reg = INVALID_REGNUM;
HOST_WIDE_INT offset = 0;
switch (GET_CODE (rtl))
{
case REG:
/* RA is in a register. */
reg = DWARF_FRAME_REGNUM (REGNO (rtl));
break;
case MEM:
/* RA is on the stack. */
rtl = XEXP (rtl, 0);
switch (GET_CODE (rtl))
{
case REG:
gcc_assert (REGNO (rtl) == STACK_POINTER_REGNUM);
offset = 0;
break;
case PLUS:
gcc_assert (REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM);
offset = INTVAL (XEXP (rtl, 1));
break;
case MINUS:
gcc_assert (REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM);
offset = -INTVAL (XEXP (rtl, 1));
break;
default:
gcc_unreachable ();
}
break;
case PLUS:
/* The return address is at some offset from any value we can
actually load. For instance, on the SPARC it is in %i7+8. Just
ignore the offset for now; it doesn't matter for unwinding frames. */
gcc_assert (CONST_INT_P (XEXP (rtl, 1)));
initial_return_save (XEXP (rtl, 0));
return;
default:
gcc_unreachable ();
}
if (reg != DWARF_FRAME_RETURN_COLUMN)
{
if (reg != INVALID_REGNUM)
record_reg_saved_in_reg (rtl, pc_rtx);
reg_save (DWARF_FRAME_RETURN_COLUMN, reg, offset - cfa.offset);
}
}
/* Annotate the function with NOTE_INSN_CFI notes to record the CFI
state at each location within the function. These notes will be
@ -2569,7 +2572,31 @@ execute_dwarf2_frame (void)
if (targetm.debug_unwind_info () == UI_DWARF2
|| targetm_common.except_unwind_info (&global_options) == UI_DWARF2)
initial_return_save (INCOMING_RETURN_ADDR_RTX);
{
initial_return_save (INCOMING_RETURN_ADDR_RTX);
/* For a few targets, we have the return address incoming into a
register, but choose a different return column. This will result
in a DW_CFA_register for the return, and an entry in
regs_saved_in_regs to match. If the target later stores that
return address register to the stack, we want to be able to emit
the DW_CFA_offset against the return column, not the intermediate
save register. Save the contents of regs_saved_in_regs so that
we can re-initialize it at the start of each function. */
switch (VEC_length (reg_saved_in_data, regs_saved_in_regs))
{
case 0:
break;
case 1:
cie_return_save = ggc_alloc_reg_saved_in_data ();
*cie_return_save = *VEC_index (reg_saved_in_data,
regs_saved_in_regs, 0);
regs_saved_in_regs = NULL;
break;
default:
gcc_unreachable ();
}
}
add_cfi_vec = NULL;
}
@ -2588,6 +2615,9 @@ execute_dwarf2_frame (void)
memset (&cfa_temp, 0, sizeof(cfa_temp));
cfa_temp.reg = INVALID_REGNUM;
if (cie_return_save)
VEC_safe_push (reg_saved_in_data, gc, regs_saved_in_regs, cie_return_save);
dwarf2out_alloc_current_fde ();
/* Do the work. */