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[RFA] dwarf2out.c: Don't emit DW_OP_regx for register -1
- From: Kevin Buettner <kevinb at redhat dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: kevinb at redhat dot com
- Date: Thu, 6 Mar 2003 14:35:04 -0700
- Subject: [RFA] dwarf2out.c: Don't emit DW_OP_regx for register -1
On a mips64 target (and probably just mips too), when compiling at a
sufficiently high optimization level, it's possible to see DW_OP_regx
for register -1 in the DWARF 2 output. E.g,
<2><156dc>: Abbrev Number: 46 (DW_TAG_variable)
DW_AT_name : (indirect string, offset: 0x2778): addr
DW_AT_decl_file : 1
DW_AT_decl_line : 157
DW_AT_type : <13912>
<2><15a3b>: Abbrev Number: 53 (DW_TAG_variable)
DW_AT_abstract_origin: <156dc>
DW_AT_location : 6 byte block: 90 ff ff ff ff f (DW_OP_regx: 4294967295; )
The patch below prevents the above from happening when there's no
suitable mapping from internal gcc register numbers to dwarf register
numbers.
I've boostrapped and tested for regressions on i386 GNU/Linux. No
problems found.
Okay to commit?
* dwarf2out.c (reg_loc_descriptor): Don't generate DW_OP_regx
in a location expression when reg_number() is unable to provide
a suitable mapping.
Index: gcc/dwarf2out.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/dwarf2out.c,v
retrieving revision 1.406
diff -u -p -r1.406 dwarf2out.c
--- gcc/dwarf2out.c 6 Mar 2003 10:23:46 -0000 1.406
+++ gcc/dwarf2out.c 6 Mar 2003 21:02:29 -0000
@@ -8175,7 +8201,14 @@ reg_loc_descriptor (rtl)
reg = reg_number (rtl);
regs = (*targetm.dwarf_register_span) (rtl);
- if (HARD_REGNO_NREGS (reg, GET_MODE (rtl)) > 1
+ if (reg == (unsigned int) -1)
+ {
+ /* Some implementations of DBX_REGISTER_NUMBER (which is called
+ from reg_number()) use -1 to indicate that there is no mapping
+ for a given register. */
+ return 0;
+ }
+ else if (HARD_REGNO_NREGS (reg, GET_MODE (rtl)) > 1
|| regs)
return multiple_reg_loc_descriptor (rtl, regs);
else