https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86690
Bug ID: 86690
Summary: [PATCH] Duplicate field in anonymous union causes
infinite loop
Product: gcc
Version: 8.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: harjoc at gmail dot com
Target Milestone: ---
Created attachment 44449
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44449&action=edit
Test file
If a struct contains an anonymous union and both have a field with the same
name, detect_field_duplicates_hash() will replace one of them with NULL. If
compilation doesn't stop immediately, it may later call lookup_field() on the
union, which falsely assumes the union's LANG_SPECIFIC array is sorted, and may
loop indefinitely because of this.
Attached testcase hangs without -save-temps, doesn't hang with -save-temps. It
only reproduces if there is an #include <some header> for some reason.
Reproduced on amd64 since gcc-5, on ubuntu-18.04 and gentoo.
Attached patch falls back to iterate via DECL_CHAIN if there was an error
earlier during compilation.
