diff options
author | kaiw <kaiw@FreeBSD.org> | 2014-01-19 13:48:02 +0000 |
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committer | kaiw <kaiw@FreeBSD.org> | 2014-01-19 13:48:02 +0000 |
commit | 9ccc946cdb76c29bc6ec126ee139bdc025baf0a3 (patch) | |
tree | a52e3f68b3751aacd8ba14d9113bf65e89b21422 /cddl | |
parent | f87e56cfe029ecf7ccb27686adc00c8182494e76 (diff) | |
download | FreeBSD-src-9ccc946cdb76c29bc6ec126ee139bdc025baf0a3.zip FreeBSD-src-9ccc946cdb76c29bc6ec126ee139bdc025baf0a3.tar.gz |
* 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].
Diffstat (limited to 'cddl')
-rw-r--r-- | cddl/contrib/opensolaris/tools/ctf/cvt/dwarf.c | 66 |
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 201a81a..8725f15 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); |