Exception handling on the Blackfin was broken by the dataflow merge.
Inspecting the differences in the generated code, it appears that when
compiling functions like _Unwind_Resume in unwind-dw2.c, the dse pass
deletes necessary instructions.
Before:
(insn 56 55 57 7 (set (reg/v:SI 56 [ offset ])
(reg:SI 0 R0)) 14 {*movsi_insn} (expr_list:REG_DEAD (reg:SI 0 R0)
(nil)))
(insn 57 56 67 7 (set (reg/v/f:SI 55 [ handler ])
(mem/s/f/c:SI (plus:SI (reg/f:SI 15 FP)
(const_int -376 [0xfffffe88])) [12 cur_context.ra+0 S4
A32])) 14 {*movsi_insn} (nil))
(insn 67 57 68 7 (set (reg:SI 10 P2 [ offset ])
(reg/v:SI 56 [ offset ])) 14 {*movsi_insn} (expr_list:REG_DEAD
(reg/v:SI 56 [ offset ])
(nil)))
(insn 68 67 69 7 (set (mem:SI (plus:SI (reg/f:SI 15 FP)
(const_int 4 [0x4])) [0 S4 A32])
(reg/v/f:SI 55 [ handler ])) 14 {*movsi_insn}
(expr_list:REG_DEAD (reg/v/f:SI 55 [ handler ])
(nil)))
(jump_insn 69 68 0 7 (set (pc)
(unspec_volatile [
(reg:SI 10 P2)
] 0)) 126 {eh_return_internal} (expr_list:REG_DEAD (reg:SI
10 P2)
(expr_list:REG_EQUAL (unspec_volatile [
(reg:SI 10 P2)
] 0)
(nil))))
After:
(insn 56 55 67 7 (set (reg/v:SI 56 [ offset ])
(reg:SI 0 R0)) 14 {*movsi_insn} (expr_list:REG_DEAD (reg:SI 0 R0)
(nil)))
(insn 67 56 69 7 (set (reg:SI 10 P2 [ offset ])
(reg/v:SI 56 [ offset ])) 14 {*movsi_insn} (expr_list:REG_DEAD
(reg/v:SI 56 [ offset ])
(nil)))
(jump_insn 69 67 0 7 (set (pc)
(unspec_volatile [
(reg:SI 10 P2)
] 0)) 126 {eh_return_internal} (expr_list:REG_DEAD (reg:SI
10 P2)
(expr_list:REG_EQUAL (unspec_volatile [
(reg:SI 10 P2)
] 0)
(nil))))
[FP + 4] is part of the register save area. Insn 68, which stores a
value into it, gets deleted.
There is a reference to current_function_uses_eh_return in dse.c, but
it's not clear to me what it's trying to achieve. Anyway, turning the
store into an unspec_volatile solves the problem. I've committed the
following.
Bernd
--
This footer brought to you by insane German lawmakers.
Analog Devices GmbH Wilhelm-Wagenfeld-Str. 6 80807 Muenchen
Sitz der Gesellschaft Muenchen, Registergericht Muenchen HRB 40368
Geschaeftsfuehrer Thomas Wessel, William A. Martin, Margaret Seif
Index: ChangeLog
===================================================================
--- ChangeLog (revision 125680)
+++ ChangeLog (working copy)
@@ -1,3 +1,10 @@
+2007-06-13 Bernd Schmidt <[EMAIL PROTECTED]>
+
+ * config/bfin/bfin.h (EH_RETURN_HANDLER_RTX): Use gen_frame_mem.
+ * config/bfin/bfin.md (UNSPEC_VOLATILE_STORE_EH_HANDLER): New constant.
+ (eh_store_handler): New pattern.
+ (eh_return): Emit it instead of a plain move.
+
2007-06-13 Uros Bizjak <[EMAIL PROTECTED]>
* config/i386/i386.c (ix86_init_mmx_sse_builtins)
Index: config/bfin/bfin.h
===================================================================
--- config/bfin/bfin.h (revision 125641)
+++ config/bfin/bfin.h (working copy)
@@ -813,7 +813,7 @@ typedef struct {
#define EH_RETURN_DATA_REGNO(N) ((N) < 2 ? (N) : INVALID_REGNUM)
#define EH_RETURN_STACKADJ_RTX gen_rtx_REG (Pmode, REG_P2)
#define EH_RETURN_HANDLER_RTX \
- gen_rtx_MEM (Pmode, plus_constant (frame_pointer_rtx, UNITS_PER_WORD))
+ gen_frame_mem (Pmode, plus_constant (frame_pointer_rtx, UNITS_PER_WORD))
/* Addressing Modes */
Index: config/bfin/bfin.md
===================================================================
--- config/bfin/bfin.md (revision 125648)
+++ config/bfin/bfin.md (working copy)
@@ -144,7 +144,8 @@ (define_constants
[(UNSPEC_VOLATILE_EH_RETURN 0)
(UNSPEC_VOLATILE_CSYNC 1)
(UNSPEC_VOLATILE_SSYNC 2)
- (UNSPEC_VOLATILE_LOAD_FUNCDESC 3)])
+ (UNSPEC_VOLATILE_LOAD_FUNCDESC 3)
+ (UNSPEC_VOLATILE_STORE_EH_HANDLER 4)])
(define_constants
[(MACFLAG_NONE 0)
@@ -2687,12 +2688,20 @@ (define_expand "eh_return"
UNSPEC_VOLATILE_EH_RETURN)]
""
{
- emit_move_insn (EH_RETURN_HANDLER_RTX, operands[0]);
+ emit_insn (gen_eh_store_handler (EH_RETURN_HANDLER_RTX, operands[0]));
emit_jump_insn (gen_eh_return_internal ());
emit_barrier ();
DONE;
})
+(define_insn "eh_store_handler"
+ [(unspec_volatile [(match_operand:SI 1 "register_operand" "da")]
+ UNSPEC_VOLATILE_STORE_EH_HANDLER)
+ (clobber (match_operand:SI 0 "memory_operand" "=m"))]
+ ""
+ "%0 = %1%!"
+ [(set_attr "type" "mcst")])
+
(define_insn_and_split "eh_return_internal"
[(set (pc)
(unspec_volatile [(reg:SI REG_P2)] UNSPEC_VOLATILE_EH_RETURN))]
