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[027/nnn] poly_int: DWARF CFA offsets
- From: Richard Sandiford <richard dot sandiford at linaro dot org>
- To: gcc-patches at gcc dot gnu dot org
- Date: Mon, 23 Oct 2017 18:10:58 +0100
- Subject: [027/nnn] poly_int: DWARF CFA offsets
- Authentication-results: sourceware.org; auth=none
- References: <871sltvm7r.fsf@linaro.org>
This patch makes the DWARF code use poly_int64 rather than
HOST_WIDE_INT for CFA offsets. The main changes are:
- to make reg_save use a DW_CFA_expression representation when
the offset isn't constant and
- to record the CFA information alongside a def_cfa_expression
if either offset is polynomial, since it's quite difficult
to reconstruct the CFA information otherwise.
2017-10-23 Richard Sandiford <richard.sandiford@linaro.org>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>
gcc/
* gengtype.c (main): Handle poly_int64_pod.
* dwarf2out.h (dw_cfi_oprnd_cfa_loc): New dw_cfi_oprnd_type.
(dw_cfi_oprnd::dw_cfi_cfa_loc): New field.
(dw_cfa_location::offset, dw_cfa_location::base_offset): Change
from HOST_WIDE_INT to poly_int64_pod.
* dwarf2cfi.c (queued_reg_save::cfa_offset): Likewise.
(copy_cfa): New function.
(lookup_cfa_1): Use the cached dw_cfi_cfa_loc, if it exists.
(cfi_oprnd_equal_p): Handle dw_cfi_oprnd_cfa_loc.
(cfa_equal_p, dwarf2out_frame_debug_adjust_cfa)
(dwarf2out_frame_debug_cfa_offset, dwarf2out_frame_debug_expr)
(initial_return_save): Treat offsets as poly_ints.
(def_cfa_0): Likewise. Cache the CFA in dw_cfi_cfa_loc if either
offset is nonconstant.
(reg_save): Take the offset as a poly_int64. Fall back to
DW_CFA_expression for nonconstant offsets.
(queue_reg_save): Take the offset as a poly_int64.
* dwarf2out.c (dw_cfi_oprnd2_desc): Handle DW_CFA_def_cfa_expression.
Index: gcc/gengtype.c
===================================================================
--- gcc/gengtype.c 2017-10-23 17:16:50.367528682 +0100
+++ gcc/gengtype.c 2017-10-23 17:16:57.211604434 +0100
@@ -5192,6 +5192,7 @@ #define POS_HERE(Call) do { pos.file = t
POS_HERE (do_scalar_typedef ("REAL_VALUE_TYPE", &pos));
POS_HERE (do_scalar_typedef ("FIXED_VALUE_TYPE", &pos));
POS_HERE (do_scalar_typedef ("double_int", &pos));
+ POS_HERE (do_scalar_typedef ("poly_int64_pod", &pos));
POS_HERE (do_scalar_typedef ("offset_int", &pos));
POS_HERE (do_scalar_typedef ("widest_int", &pos));
POS_HERE (do_scalar_typedef ("int64_t", &pos));
Index: gcc/dwarf2out.h
===================================================================
--- gcc/dwarf2out.h 2017-10-23 17:11:40.311071579 +0100
+++ gcc/dwarf2out.h 2017-10-23 17:16:57.210604569 +0100
@@ -43,7 +43,8 @@ enum dw_cfi_oprnd_type {
dw_cfi_oprnd_reg_num,
dw_cfi_oprnd_offset,
dw_cfi_oprnd_addr,
- dw_cfi_oprnd_loc
+ dw_cfi_oprnd_loc,
+ dw_cfi_oprnd_cfa_loc
};
typedef union GTY(()) {
@@ -51,6 +52,8 @@ typedef union GTY(()) {
HOST_WIDE_INT GTY ((tag ("dw_cfi_oprnd_offset"))) dw_cfi_offset;
const char * GTY ((tag ("dw_cfi_oprnd_addr"))) dw_cfi_addr;
struct dw_loc_descr_node * GTY ((tag ("dw_cfi_oprnd_loc"))) dw_cfi_loc;
+ struct dw_cfa_location * GTY ((tag ("dw_cfi_oprnd_cfa_loc")))
+ dw_cfi_cfa_loc;
} dw_cfi_oprnd;
struct GTY(()) dw_cfi_node {
@@ -114,8 +117,8 @@ struct GTY(()) dw_fde_node {
Instead of passing around REG and OFFSET, we pass a copy
of this structure. */
struct GTY(()) dw_cfa_location {
- HOST_WIDE_INT offset;
- HOST_WIDE_INT base_offset;
+ poly_int64_pod offset;
+ poly_int64_pod base_offset;
/* REG is in DWARF_FRAME_REGNUM space, *not* normal REGNO space. */
unsigned int reg;
BOOL_BITFIELD indirect : 1; /* 1 if CFA is accessed via a dereference. */
Index: gcc/dwarf2cfi.c
===================================================================
--- gcc/dwarf2cfi.c 2017-10-23 17:07:41.013611927 +0100
+++ gcc/dwarf2cfi.c 2017-10-23 17:16:57.208604839 +0100
@@ -206,7 +206,7 @@ static GTY(()) unsigned long dwarf2out_c
struct queued_reg_save {
rtx reg;
rtx saved_reg;
- HOST_WIDE_INT cfa_offset;
+ poly_int64_pod cfa_offset;
};
@@ -434,6 +434,16 @@ copy_cfi_row (dw_cfi_row *src)
return dst;
}
+/* Return a copy of an existing CFA location. */
+
+static dw_cfa_location *
+copy_cfa (dw_cfa_location *src)
+{
+ dw_cfa_location *dst = ggc_alloc<dw_cfa_location> ();
+ *dst = *src;
+ return dst;
+}
+
/* Generate a new label for the CFI info to refer to. */
static char *
@@ -629,7 +639,10 @@ lookup_cfa_1 (dw_cfi_ref cfi, dw_cfa_loc
loc->offset = cfi->dw_cfi_oprnd2.dw_cfi_offset;
break;
case DW_CFA_def_cfa_expression:
- get_cfa_from_loc_descr (loc, cfi->dw_cfi_oprnd1.dw_cfi_loc);
+ if (cfi->dw_cfi_oprnd2.dw_cfi_cfa_loc)
+ *loc = *cfi->dw_cfi_oprnd2.dw_cfi_cfa_loc;
+ else
+ get_cfa_from_loc_descr (loc, cfi->dw_cfi_oprnd1.dw_cfi_loc);
break;
case DW_CFA_remember_state:
@@ -654,10 +667,10 @@ lookup_cfa_1 (dw_cfi_ref cfi, dw_cfa_loc
cfa_equal_p (const dw_cfa_location *loc1, const dw_cfa_location *loc2)
{
return (loc1->reg == loc2->reg
- && loc1->offset == loc2->offset
+ && must_eq (loc1->offset, loc2->offset)
&& loc1->indirect == loc2->indirect
&& (loc1->indirect == 0
- || loc1->base_offset == loc2->base_offset));
+ || must_eq (loc1->base_offset, loc2->base_offset)));
}
/* Determine if two CFI operands are identical. */
@@ -678,6 +691,8 @@ cfi_oprnd_equal_p (enum dw_cfi_oprnd_typ
|| strcmp (a->dw_cfi_addr, b->dw_cfi_addr) == 0);
case dw_cfi_oprnd_loc:
return loc_descr_equal_p (a->dw_cfi_loc, b->dw_cfi_loc);
+ case dw_cfi_oprnd_cfa_loc:
+ return cfa_equal_p (a->dw_cfi_cfa_loc, b->dw_cfi_cfa_loc);
}
gcc_unreachable ();
}
@@ -758,19 +773,23 @@ def_cfa_0 (dw_cfa_location *old_cfa, dw_
cfi = new_cfi ();
- if (new_cfa->reg == old_cfa->reg && !new_cfa->indirect && !old_cfa->indirect)
+ HOST_WIDE_INT const_offset;
+ if (new_cfa->reg == old_cfa->reg
+ && !new_cfa->indirect
+ && !old_cfa->indirect
+ && new_cfa->offset.is_constant (&const_offset))
{
/* Construct a "DW_CFA_def_cfa_offset <offset>" instruction, indicating
the CFA register did not change but the offset did. The data
factoring for DW_CFA_def_cfa_offset_sf happens in output_cfi, or
in the assembler via the .cfi_def_cfa_offset directive. */
- if (new_cfa->offset < 0)
+ if (const_offset < 0)
cfi->dw_cfi_opc = DW_CFA_def_cfa_offset_sf;
else
cfi->dw_cfi_opc = DW_CFA_def_cfa_offset;
- cfi->dw_cfi_oprnd1.dw_cfi_offset = new_cfa->offset;
+ cfi->dw_cfi_oprnd1.dw_cfi_offset = const_offset;
}
- else if (new_cfa->offset == old_cfa->offset
+ else if (must_eq (new_cfa->offset, old_cfa->offset)
&& old_cfa->reg != INVALID_REGNUM
&& !new_cfa->indirect
&& !old_cfa->indirect)
@@ -781,19 +800,20 @@ def_cfa_0 (dw_cfa_location *old_cfa, dw_
cfi->dw_cfi_opc = DW_CFA_def_cfa_register;
cfi->dw_cfi_oprnd1.dw_cfi_reg_num = new_cfa->reg;
}
- else if (new_cfa->indirect == 0)
+ else if (new_cfa->indirect == 0
+ && new_cfa->offset.is_constant (&const_offset))
{
/* Construct a "DW_CFA_def_cfa <register> <offset>" instruction,
indicating the CFA register has changed to <register> with
the specified offset. The data factoring for DW_CFA_def_cfa_sf
happens in output_cfi, or in the assembler via the .cfi_def_cfa
directive. */
- if (new_cfa->offset < 0)
+ if (const_offset < 0)
cfi->dw_cfi_opc = DW_CFA_def_cfa_sf;
else
cfi->dw_cfi_opc = DW_CFA_def_cfa;
cfi->dw_cfi_oprnd1.dw_cfi_reg_num = new_cfa->reg;
- cfi->dw_cfi_oprnd2.dw_cfi_offset = new_cfa->offset;
+ cfi->dw_cfi_oprnd2.dw_cfi_offset = const_offset;
}
else
{
@@ -805,6 +825,13 @@ def_cfa_0 (dw_cfa_location *old_cfa, dw_
cfi->dw_cfi_opc = DW_CFA_def_cfa_expression;
loc_list = build_cfa_loc (new_cfa, 0);
cfi->dw_cfi_oprnd1.dw_cfi_loc = loc_list;
+ if (!new_cfa->offset.is_constant ()
+ || !new_cfa->base_offset.is_constant ())
+ /* It's hard to reconstruct the CFA location for a polynomial
+ expression, so just cache it instead. */
+ cfi->dw_cfi_oprnd2.dw_cfi_cfa_loc = copy_cfa (new_cfa);
+ else
+ cfi->dw_cfi_oprnd2.dw_cfi_cfa_loc = NULL;
}
return cfi;
@@ -836,33 +863,42 @@ def_cfa_1 (dw_cfa_location *new_cfa)
otherwise it is saved in SREG. */
static void
-reg_save (unsigned int reg, unsigned int sreg, HOST_WIDE_INT offset)
+reg_save (unsigned int reg, unsigned int sreg, poly_int64 offset)
{
dw_fde_ref fde = cfun ? cfun->fde : NULL;
dw_cfi_ref cfi = new_cfi ();
cfi->dw_cfi_oprnd1.dw_cfi_reg_num = reg;
- /* When stack is aligned, store REG using DW_CFA_expression with FP. */
- if (fde
- && fde->stack_realign
- && sreg == INVALID_REGNUM)
- {
- cfi->dw_cfi_opc = DW_CFA_expression;
- cfi->dw_cfi_oprnd1.dw_cfi_reg_num = reg;
- cfi->dw_cfi_oprnd2.dw_cfi_loc
- = build_cfa_aligned_loc (&cur_row->cfa, offset,
- fde->stack_realignment);
- }
- else if (sreg == INVALID_REGNUM)
- {
- if (need_data_align_sf_opcode (offset))
- cfi->dw_cfi_opc = DW_CFA_offset_extended_sf;
- else if (reg & ~0x3f)
- cfi->dw_cfi_opc = DW_CFA_offset_extended;
+ if (sreg == INVALID_REGNUM)
+ {
+ HOST_WIDE_INT const_offset;
+ /* When stack is aligned, store REG using DW_CFA_expression with FP. */
+ if (fde && fde->stack_realign)
+ {
+ cfi->dw_cfi_opc = DW_CFA_expression;
+ cfi->dw_cfi_oprnd1.dw_cfi_reg_num = reg;
+ cfi->dw_cfi_oprnd2.dw_cfi_loc
+ = build_cfa_aligned_loc (&cur_row->cfa, offset,
+ fde->stack_realignment);
+ }
+ else if (offset.is_constant (&const_offset))
+ {
+ if (need_data_align_sf_opcode (const_offset))
+ cfi->dw_cfi_opc = DW_CFA_offset_extended_sf;
+ else if (reg & ~0x3f)
+ cfi->dw_cfi_opc = DW_CFA_offset_extended;
+ else
+ cfi->dw_cfi_opc = DW_CFA_offset;
+ cfi->dw_cfi_oprnd2.dw_cfi_offset = const_offset;
+ }
else
- cfi->dw_cfi_opc = DW_CFA_offset;
- cfi->dw_cfi_oprnd2.dw_cfi_offset = offset;
+ {
+ cfi->dw_cfi_opc = DW_CFA_expression;
+ cfi->dw_cfi_oprnd1.dw_cfi_reg_num = reg;
+ cfi->dw_cfi_oprnd2.dw_cfi_loc
+ = build_cfa_loc (&cur_row->cfa, offset);
+ }
}
else if (sreg == reg)
{
@@ -995,7 +1031,7 @@ record_reg_saved_in_reg (rtx dest, rtx s
SREG, or if SREG is NULL then it is saved at OFFSET to the CFA. */
static void
-queue_reg_save (rtx reg, rtx sreg, HOST_WIDE_INT offset)
+queue_reg_save (rtx reg, rtx sreg, poly_int64 offset)
{
queued_reg_save *q;
queued_reg_save e = {reg, sreg, offset};
@@ -1097,20 +1133,11 @@ dwarf2out_frame_debug_def_cfa (rtx pat)
{
memset (cur_cfa, 0, sizeof (*cur_cfa));
- if (GET_CODE (pat) == PLUS)
- {
- cur_cfa->offset = INTVAL (XEXP (pat, 1));
- pat = XEXP (pat, 0);
- }
+ pat = strip_offset (pat, &cur_cfa->offset);
if (MEM_P (pat))
{
cur_cfa->indirect = 1;
- pat = XEXP (pat, 0);
- if (GET_CODE (pat) == PLUS)
- {
- cur_cfa->base_offset = INTVAL (XEXP (pat, 1));
- pat = XEXP (pat, 0);
- }
+ pat = strip_offset (XEXP (pat, 0), &cur_cfa->base_offset);
}
/* ??? If this fails, we could be calling into the _loc functions to
define a full expression. So far no port does that. */
@@ -1133,7 +1160,7 @@ dwarf2out_frame_debug_adjust_cfa (rtx pa
{
case PLUS:
gcc_assert (dwf_regno (XEXP (src, 0)) == cur_cfa->reg);
- cur_cfa->offset -= INTVAL (XEXP (src, 1));
+ cur_cfa->offset -= rtx_to_poly_int64 (XEXP (src, 1));
break;
case REG:
@@ -1152,7 +1179,7 @@ dwarf2out_frame_debug_adjust_cfa (rtx pa
static void
dwarf2out_frame_debug_cfa_offset (rtx set)
{
- HOST_WIDE_INT offset;
+ poly_int64 offset;
rtx src, addr, span;
unsigned int sregno;
@@ -1170,7 +1197,7 @@ dwarf2out_frame_debug_cfa_offset (rtx se
break;
case PLUS:
gcc_assert (dwf_regno (XEXP (addr, 0)) == cur_cfa->reg);
- offset = INTVAL (XEXP (addr, 1)) - cur_cfa->offset;
+ offset = rtx_to_poly_int64 (XEXP (addr, 1)) - cur_cfa->offset;
break;
default:
gcc_unreachable ();
@@ -1195,7 +1222,7 @@ dwarf2out_frame_debug_cfa_offset (rtx se
{
/* We have a PARALLEL describing where the contents of SRC live.
Adjust the offset for each piece of the PARALLEL. */
- HOST_WIDE_INT span_offset = offset;
+ poly_int64 span_offset = offset;
gcc_assert (GET_CODE (span) == PARALLEL);
@@ -1535,7 +1562,7 @@ dwarf2out_frame_debug_cfa_window_save (v
dwarf2out_frame_debug_expr (rtx expr)
{
rtx src, dest, span;
- HOST_WIDE_INT offset;
+ poly_int64 offset;
dw_fde_ref fde;
/* If RTX_FRAME_RELATED_P is set on a PARALLEL, process each member of
@@ -1639,19 +1666,14 @@ dwarf2out_frame_debug_expr (rtx expr)
{
/* Rule 2 */
/* Adjusting SP. */
- switch (GET_CODE (XEXP (src, 1)))
+ if (REG_P (XEXP (src, 1)))
{
- case CONST_INT:
- offset = INTVAL (XEXP (src, 1));
- break;
- case REG:
gcc_assert (dwf_regno (XEXP (src, 1))
== cur_trace->cfa_temp.reg);
offset = cur_trace->cfa_temp.offset;
- break;
- default:
- gcc_unreachable ();
}
+ else if (!poly_int_rtx_p (XEXP (src, 1), &offset))
+ gcc_unreachable ();
if (XEXP (src, 0) == hard_frame_pointer_rtx)
{
@@ -1680,9 +1702,8 @@ dwarf2out_frame_debug_expr (rtx expr)
gcc_assert (frame_pointer_needed);
gcc_assert (REG_P (XEXP (src, 0))
- && dwf_regno (XEXP (src, 0)) == cur_cfa->reg
- && CONST_INT_P (XEXP (src, 1)));
- offset = INTVAL (XEXP (src, 1));
+ && dwf_regno (XEXP (src, 0)) == cur_cfa->reg);
+ offset = rtx_to_poly_int64 (XEXP (src, 1));
if (GET_CODE (src) != MINUS)
offset = -offset;
cur_cfa->offset += offset;
@@ -1695,11 +1716,11 @@ dwarf2out_frame_debug_expr (rtx expr)
/* Rule 4 */
if (REG_P (XEXP (src, 0))
&& dwf_regno (XEXP (src, 0)) == cur_cfa->reg
- && CONST_INT_P (XEXP (src, 1)))
+ && poly_int_rtx_p (XEXP (src, 1), &offset))
{
/* Setting a temporary CFA register that will be copied
into the FP later on. */
- offset = - INTVAL (XEXP (src, 1));
+ offset = -offset;
cur_cfa->offset += offset;
cur_cfa->reg = dwf_regno (dest);
/* Or used to save regs to the stack. */
@@ -1722,11 +1743,9 @@ dwarf2out_frame_debug_expr (rtx expr)
/* Rule 9 */
else if (GET_CODE (src) == LO_SUM
- && CONST_INT_P (XEXP (src, 1)))
- {
- cur_trace->cfa_temp.reg = dwf_regno (dest);
- cur_trace->cfa_temp.offset = INTVAL (XEXP (src, 1));
- }
+ && poly_int_rtx_p (XEXP (src, 1),
+ &cur_trace->cfa_temp.offset))
+ cur_trace->cfa_temp.reg = dwf_regno (dest);
else
gcc_unreachable ();
}
@@ -1734,8 +1753,9 @@ dwarf2out_frame_debug_expr (rtx expr)
/* Rule 6 */
case CONST_INT:
+ case POLY_INT_CST:
cur_trace->cfa_temp.reg = dwf_regno (dest);
- cur_trace->cfa_temp.offset = INTVAL (src);
+ cur_trace->cfa_temp.offset = rtx_to_poly_int64 (src);
break;
/* Rule 7 */
@@ -1745,7 +1765,11 @@ dwarf2out_frame_debug_expr (rtx expr)
&& CONST_INT_P (XEXP (src, 1)));
cur_trace->cfa_temp.reg = dwf_regno (dest);
- cur_trace->cfa_temp.offset |= INTVAL (XEXP (src, 1));
+ if (!can_ior_p (cur_trace->cfa_temp.offset, INTVAL (XEXP (src, 1)),
+ &cur_trace->cfa_temp.offset))
+ /* The target shouldn't generate this kind of CFI note if we
+ can't represent it. */
+ gcc_unreachable ();
break;
/* Skip over HIGH, assuming it will be followed by a LO_SUM,
@@ -1800,9 +1824,7 @@ dwarf2out_frame_debug_expr (rtx expr)
case PRE_MODIFY:
case POST_MODIFY:
/* We can't handle variable size modifications. */
- gcc_assert (GET_CODE (XEXP (XEXP (XEXP (dest, 0), 1), 1))
- == CONST_INT);
- offset = -INTVAL (XEXP (XEXP (XEXP (dest, 0), 1), 1));
+ offset = -rtx_to_poly_int64 (XEXP (XEXP (XEXP (dest, 0), 1), 1));
gcc_assert (REGNO (XEXP (XEXP (dest, 0), 0)) == STACK_POINTER_REGNUM
&& cur_trace->cfa_store.reg == dw_stack_pointer_regnum);
@@ -1860,9 +1882,8 @@ dwarf2out_frame_debug_expr (rtx expr)
{
unsigned int regno;
- gcc_assert (CONST_INT_P (XEXP (XEXP (dest, 0), 1))
- && REG_P (XEXP (XEXP (dest, 0), 0)));
- offset = INTVAL (XEXP (XEXP (dest, 0), 1));
+ gcc_assert (REG_P (XEXP (XEXP (dest, 0), 0)));
+ offset = rtx_to_poly_int64 (XEXP (XEXP (dest, 0), 1));
if (GET_CODE (XEXP (dest, 0)) == MINUS)
offset = -offset;
@@ -1923,7 +1944,7 @@ dwarf2out_frame_debug_expr (rtx expr)
{
/* We're storing the current CFA reg into the stack. */
- if (cur_cfa->offset == 0)
+ if (known_zero (cur_cfa->offset))
{
/* Rule 19 */
/* If stack is aligned, putting CFA reg into stack means
@@ -1981,7 +2002,7 @@ dwarf2out_frame_debug_expr (rtx expr)
{
/* We have a PARALLEL describing where the contents of SRC live.
Queue register saves for each piece of the PARALLEL. */
- HOST_WIDE_INT span_offset = offset;
+ poly_int64 span_offset = offset;
gcc_assert (GET_CODE (span) == PARALLEL);
@@ -2884,7 +2905,7 @@ create_pseudo_cfg (void)
initial_return_save (rtx rtl)
{
unsigned int reg = INVALID_REGNUM;
- HOST_WIDE_INT offset = 0;
+ poly_int64 offset = 0;
switch (GET_CODE (rtl))
{
@@ -2905,12 +2926,12 @@ initial_return_save (rtx rtl)
case PLUS:
gcc_assert (REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM);
- offset = INTVAL (XEXP (rtl, 1));
+ offset = rtx_to_poly_int64 (XEXP (rtl, 1));
break;
case MINUS:
gcc_assert (REGNO (XEXP (rtl, 0)) == STACK_POINTER_REGNUM);
- offset = -INTVAL (XEXP (rtl, 1));
+ offset = -rtx_to_poly_int64 (XEXP (rtl, 1));
break;
default:
Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c 2017-10-23 17:16:50.362529357 +0100
+++ gcc/dwarf2out.c 2017-10-23 17:16:57.210604569 +0100
@@ -570,6 +570,9 @@ dw_cfi_oprnd2_desc (enum dwarf_call_fram
case DW_CFA_val_expression:
return dw_cfi_oprnd_loc;
+ case DW_CFA_def_cfa_expression:
+ return dw_cfi_oprnd_cfa_loc;
+
default:
return dw_cfi_oprnd_unused;
}