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tru64 ldgp linker bug workaround
- To: gcc-patches at gcc dot gnu dot org
- Subject: tru64 ldgp linker bug workaround
- From: Richard Henderson <rth at redhat dot com>
- Date: Mon, 11 Jun 2001 09:32:36 -0700
Instead of using ldgp in the exception_receiver, save it away
in a pseudo at the beginning of the function and restore it in
the receiver.
r~
* config/alpha/osf5.h (TARGET_LD_BUGGY_LDGP): New.
* config/alpha/alpha.h (TARGET_LD_BUGGY_LDGP): Default.
(struct machine_function): Add gp_save_rtx.
* config/alpha/alpha.c (alpha_mark_machine_status): Mark it.
(alpha_gp_save_rtx): New.
* config/alpha/alpha-protos.h: Declare it.
* config/alpha/alpha.md (exception_receiver): Make an expander.
Use alpha_gp_save_rtx if TARGET_LD_BUGGY_LDGP.
Index: alpha-protos.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/alpha/alpha-protos.h,v
retrieving revision 1.14
diff -c -p -d -r1.14 alpha-protos.h
*** alpha-protos.h 2000/11/22 00:59:11 1.14
--- alpha-protos.h 2001/06/11 16:04:39
*************** extern int alpha_expand_block_move PARAM
*** 100,105 ****
--- 100,106 ----
extern int alpha_expand_block_clear PARAMS ((rtx []));
extern int alpha_adjust_cost PARAMS ((rtx, rtx, rtx, int));
extern rtx alpha_return_addr PARAMS ((int, rtx));
+ extern rtx alpha_gp_save_rtx PARAMS ((void));
extern void print_operand PARAMS ((FILE *, rtx, int));
extern void print_operand_address PARAMS ((FILE *, rtx));
extern void alpha_initialize_trampoline PARAMS ((rtx, rtx, rtx, int, int, int));
Index: alpha.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/alpha/alpha.c,v
retrieving revision 1.155.4.4
diff -c -p -d -r1.155.4.4 alpha.c
*** alpha.c 2001/06/10 23:09:49 1.155.4.4
--- alpha.c 2001/06/11 16:04:39
*************** alpha_mark_machine_status (p)
*** 3678,3683 ****
--- 3678,3684 ----
if (machine)
{
ggc_mark_rtx (machine->ra_rtx);
+ ggc_mark_rtx (machine->gp_save_rtx);
}
}
*************** alpha_return_addr (count, frame)
*** 3711,3716 ****
--- 3712,3740 ----
init = gen_rtx_SET (VOIDmode, reg, gen_rtx_REG (Pmode, REG_RA));
/* Emit the insn to the prologue with the other argument copies. */
+ push_topmost_sequence ();
+ emit_insn_after (init, get_insns ());
+ pop_topmost_sequence ();
+ }
+
+ return reg;
+ }
+
+ /* Return or create a pseudo containing the gp value for the current
+ function. Needed only if TARGET_LD_BUGGY_LDGP. */
+
+ rtx
+ alpha_gp_save_rtx ()
+ {
+ rtx init, reg;
+
+ reg = cfun->machine->gp_save_rtx;
+ if (reg == NULL)
+ {
+ reg = gen_reg_rtx (DImode);
+ cfun->machine->gp_save_rtx = reg;
+ init = gen_rtx_SET (VOIDmode, reg, gen_rtx_REG (DImode, 29));
+
push_topmost_sequence ();
emit_insn_after (init, get_insns ());
pop_topmost_sequence ();
Index: alpha.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/alpha/alpha.h,v
retrieving revision 1.113.4.3
diff -c -p -d -r1.113.4.3 alpha.h
*** alpha.h 2001/06/10 23:09:49 1.113.4.3
--- alpha.h 2001/06/11 16:04:39
*************** extern enum alpha_fp_trap_mode alpha_fpt
*** 186,191 ****
--- 186,194 ----
#ifndef TARGET_PROFILING_NEEDS_GP
#define TARGET_PROFILING_NEEDS_GP 0
#endif
+ #ifndef TARGET_LD_BUGGY_LDGP
+ #define TARGET_LD_BUGGY_LDGP 0
+ #endif
/* Macro to define tables used to set the flags.
This is a list in braces of pairs in braces,
*************** struct machine_function
*** 1199,1204 ****
--- 1202,1210 ----
{
/* If non-null, this rtx holds the return address for the function. */
struct rtx_def *ra_rtx;
+
+ /* If non-null, this rtx holds a saved copy of the GP for the function. */
+ struct rtx_def *gp_save_rtx;
};
/* Make (or fake) .linkage entry for function call.
Index: alpha.md
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/alpha/alpha.md,v
retrieving revision 1.136.4.4
diff -c -p -d -r1.136.4.4 alpha.md
*** alpha.md 2001/05/25 20:05:32 1.136.4.4
--- alpha.md 2001/06/11 16:04:39
***************
*** 5959,5970 ****
[(set_attr "length" "12")
(set_attr "type" "multi")])
! (define_insn "exception_receiver"
! [(unspec_volatile [(const_int 0)] 7)]
"! TARGET_OPEN_VMS && ! TARGET_WINDOWS_NT"
"ldgp $29,0($26)"
[(set_attr "length" "8")
(set_attr "type" "multi")])
(define_expand "nonlocal_goto_receiver"
[(unspec_volatile [(const_int 0)] 1)
--- 5959,5993 ----
[(set_attr "length" "12")
(set_attr "type" "multi")])
! (define_expand "exception_receiver"
! [(unspec_volatile [(match_dup 0)] 7)]
"! TARGET_OPEN_VMS && ! TARGET_WINDOWS_NT"
+ "
+ {
+ if (TARGET_LD_BUGGY_LDGP)
+ operands[0] = alpha_gp_save_rtx ();
+ else
+ operands[0] = const0_rtx;
+ }")
+
+ (define_insn "*exception_receiver_1"
+ [(unspec_volatile [(const_int 0)] 7)]
+ "! TARGET_LD_BUGGY_LDGP"
"ldgp $29,0($26)"
[(set_attr "length" "8")
(set_attr "type" "multi")])
+
+ ;; ??? We don't represent the usage of $29 properly in address loads
+ ;; and function calls. This leads to the following move being deleted
+ ;; as dead code unless it is represented as a volatile unspec.
+
+ (define_insn "*exception_receiver_2"
+ [(unspec_volatile [(match_operand:DI 0 "nonimmediate_operand" "r,m")] 7)]
+ "TARGET_LD_BUGGY_LDGP"
+ "@
+ mov %0,$29
+ ldq $29,%0"
+ [(set_attr "type" "ilog,ild")])
(define_expand "nonlocal_goto_receiver"
[(unspec_volatile [(const_int 0)] 1)
Index: osf5.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/alpha/osf5.h,v
retrieving revision 1.1.12.2
diff -c -p -d -r1.1.12.2 osf5.h
*** osf5.h 2001/06/11 02:30:40 1.1.12.2
--- osf5.h 2001/06/11 16:04:39
***************
*** 46,48 ****
--- 46,54 ----
#undef ASM_OLDAS_SPEC
#define ASM_OLDAS_SPEC "-oldas -c"
+
+ /* The linker appears to perform invalid code optimizations that result
+ in the ldgp emitted for the exception_receiver pattern being incorrctly
+ linked. */
+ #undef TARGET_LD_BUGGY_LDGP
+ #define TARGET_LD_BUGGY_LDGP 1