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authorKai Wang <kaiw@FreeBSD.org>2014-01-19 13:48:02 +0000
committerKai Wang <kaiw@FreeBSD.org>2014-01-19 13:48:02 +0000
commite3fa6e64ee1ed08584667538818259a36147041f (patch)
treea52e3f68b3751aacd8ba14d9113bf65e89b21422 /cddl/contrib/opensolaris/tools
parentbc5fce8d8f854b49cfc338425fc1eb948486727b (diff)
downloadsrc-e3fa6e64ee1ed08584667538818259a36147041f.tar.gz
src-e3fa6e64ee1ed08584667538818259a36147041f.zip
* Make die_mem_offset() be able to handle DW_AT_data_member_location
attributes generated by Clang 3.4. * Document how different compilers generate DW_AT_data_member_location attributes differently. * Document the quirks about DW_FORM_data[48].
Notes
Notes: svn path=/projects/elftoolchain/; revision=260880
Diffstat (limited to 'cddl/contrib/opensolaris/tools')
-rw-r--r--cddl/contrib/opensolaris/tools/ctf/cvt/dwarf.c66
1 files changed, 57 insertions, 9 deletions
diff --git a/cddl/contrib/opensolaris/tools/ctf/cvt/dwarf.c b/cddl/contrib/opensolaris/tools/ctf/cvt/dwarf.c
index 201a81ae94ff..8725f15631df 100644
--- a/cddl/contrib/opensolaris/tools/ctf/cvt/dwarf.c
+++ b/cddl/contrib/opensolaris/tools/ctf/cvt/dwarf.c
@@ -492,23 +492,71 @@ die_mem_offset(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name,
Dwarf_Locdesc *loc = NULL;
Dwarf_Signed locnum = 0;
Dwarf_Attribute at;
+ Dwarf_Half form;
+
+ if (name != DW_AT_data_member_location)
+ terminate("die %llu: can only process attribute "
+ "DW_AT_data_member_location\n", die_off(dw, die));
if ((at = die_attr(dw, die, name, 0)) == NULL)
return (0);
- if (dwarf_loclist(at, &loc, &locnum, &dw->dw_err) != DW_DLV_OK)
+ if (dwarf_whatform(at, &form, &dw->dw_err) != DW_DLV_OK)
return (0);
- if (locnum != 1 || loc->ld_s->lr_atom != DW_OP_plus_uconst) {
- terminate("die %llu: cannot parse member offset\n",
- die_off(dw, die));
- }
+ switch (form) {
+ case DW_FORM_sec_offset:
+ case DW_FORM_block:
+ case DW_FORM_block1:
+ case DW_FORM_block2:
+ case DW_FORM_block4:
+ /*
+ * GCC in base and Clang (3.3 or below) generates
+ * DW_AT_data_member_location attribute with DW_FORM_block*
+ * form. The attribute contains one DW_OP_plus_uconst
+ * operator. The member offset stores in the operand.
+ */
+ if (dwarf_loclist(at, &loc, &locnum, &dw->dw_err) != DW_DLV_OK)
+ return (0);
+ if (locnum != 1 || loc->ld_s->lr_atom != DW_OP_plus_uconst) {
+ terminate("die %llu: cannot parse member offset with "
+ "operator other than DW_OP_plus_uconst\n",
+ die_off(dw, die));
+ }
+ *valp = loc->ld_s->lr_number;
+ if (loc != NULL) {
+ dwarf_dealloc(dw->dw_dw, loc->ld_s, DW_DLA_LOC_BLOCK);
+ dwarf_dealloc(dw->dw_dw, loc, DW_DLA_LOCDESC);
+ }
+ break;
- *valp = loc->ld_s->lr_number;
+ case DW_FORM_data1:
+ case DW_FORM_data2:
+ case DW_FORM_data4:
+ case DW_FORM_data8:
+ case DW_FORM_udata:
+ /*
+ * Clang 3.4 generates DW_AT_data_member_location attribute
+ * with DW_FORM_data* form (constant class). The attribute
+ * stores a contant value which is the member offset.
+ *
+ * However, note that DW_FORM_data[48] in DWARF version 2 or 3
+ * could be used as a section offset (offset into .debug_loc in
+ * this case). Here we assume the attribute always stores a
+ * constant because we know Clang 3.4 does this and GCC in
+ * base won't emit DW_FORM_data[48] for this attribute. This
+ * code will remain correct if future vesrions of Clang and
+ * GCC conform to DWARF4 standard and only use the form
+ * DW_FORM_sec_offset for section offset.
+ */
+ if (dwarf_attrval_unsigned(die, name, valp, &dw->dw_err) !=
+ DW_DLV_OK)
+ return (0);
+ break;
- if (loc != NULL) {
- dwarf_dealloc(dw->dw_dw, loc->ld_s, DW_DLA_LOC_BLOCK);
- dwarf_dealloc(dw->dw_dw, loc, DW_DLA_LOCDESC);
+ default:
+ terminate("die %llu: cannot parse member offset with form "
+ "%u\n", die_off(dw, die), form);
}
return (1);