ld: change DWARF output for structs

The debug/dwarf package cannot parse the format generated here,
but the format can be changed so it does.
After this edit, tweaking the expression defining the offset
of a struct field, the dwarf package can parse the tables (again?).

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/105710043

diff --git a/src/cmd/ld/dwarf.c b/src/cmd/ld/dwarf.c
index a9f93299322b3d259f27a74bf6acf9068fc75dcc..90c6725bc729bad2655b646311b66831b413fec0 100644 (file)
--- a/src/cmd/ld/dwarf.c
+++ b/src/cmd/ld/dwarf.c
@@ -835,11 +835,8 @@ newmemberoffsetattr(DWDie *die, int32 offs)
        int i;
 
        i = 0;
-       if (offs != 0) {
-               block[i++] = DW_OP_consts;
-               i += sleb128enc(offs, block+i);
-               block[i++] = DW_OP_plus;
-       }
+       block[i++] = DW_OP_plus_uconst;
+       i += uleb128enc(offs, block+i);
        newattr(die, DW_AT_data_member_location, DW_CLS_BLOCK, i, mal(i));
        memmove(die->attr->data, block, i);
 }