https://sourceware.org/bugzilla/show_bug.cgi?id=28294
Bug ID: 28294 Summary: dwarf_aggregate_size fails on some array types Product: elfutils Version: unspecified Status: UNCONFIRMED Severity: normal Priority: P2 Component: libdw Assignee: unassigned at sourceware dot org Reporter: egb.atos at gmail dot com CC: elfutils-devel at sourceware dot org Target Milestone: --- In dwarf_aggregate_size.c, the helper function array_size unconditionally uses dwarf_formsdata to obtain the value of the DW_AT_upper_bound attribute for array types. In many cases, this will return a negative value for C arrays that have positive upper bounds, causing the function to return a failure value, which propagates up through dwarf_aggregate_size. This is an exemplary type (via readelf -w): <1><90e>: Abbrev Number: 37 (DW_TAG_array_type) <90f> DW_AT_type : <0x118> <2><913>: Abbrev Number: 11 (DW_TAG_subrange_type) <914> DW_AT_type : <0x2c> <918> DW_AT_upper_bound : 249 And the same type, via eu-readelf --debug-dump=info: [ 90e] array_type abbrev: 37 type (ref4) [ 118] [ 913] subrange_type abbrev: 11 type (ref4) [ 2c] upper_bound (data1) 249 If dwarf_aggregate_size is called on this type, when it gets the upper_bound attribute, it will get a value of -7, and fail. For other array sizes, this will work. Looking around a bit, the closest discussion I could find on the topic was this one about signed vs unsigned interpretation of array bounds back in 2005: http://www.dwarfstd.org/ShowIssue.php?issue=020702.1 I exchanged emails with Mark Wielaard on this, and he indicated that this did appear to be a bug, but he wasn't sure yet where the correct fix would be. I've tried this with a RISCV compiler (version 8.3.0), an ARM compiler (version 7.3.1) and an x86 gcc (version 7.5.0). I've not tried it with later versions. Here's the sample code I compiled to get the output above. The output in the report is from the ARM compiler. #include <string.h> int foofunc(int v, char *s) { char buff[250]; strcpy(buff, s); return buff[v]; } int main() { return foofunc(4, "fdjkfd"); } -- You are receiving this mail because: You are on the CC list for the bug.