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* Make die_mem_offset() be able to handle DW_AT_data_member_location

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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].
This commit is contained in:
Kai Wang 2014-01-19 13:48:02 +00:00
parent bc5fce8d8f
commit e3fa6e64ee
1 changed files with 57 additions and 9 deletions
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66
cddl/contrib/opensolaris/tools/ctf/cvt/dwarf.c
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@ -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);