https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94150
Bug ID: 94150
Summary: Improve LTO diagnosis for LTO triggered
warnings/error: print source.o or source.a(lib.o) when
printing location
Product: gcc
Version: lto
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: lto
Assignee: unassigned at gcc dot gnu.org
Reporter: romain.geissler at amadeus dot com
CC: marxin at gcc dot gnu.org
Target Milestone: ---
Hi,
When LTO warnings/error are reported and print a given location, it would be
nice to not only print the C/C++ file name, but also from which .o or .a
library it comes from.
Example of -Werror=lto-type-mistmatch I just got because I was mixing
incompatible .o built against different version of the same header file
"toolbox/UTF8Utils.h":
/remote/intdeliv/components/mdw/Toolbox/18-0-0-56/include/toolbox/UTF8Utils.h:106:
error: type of ‘operator[]’ does not match original declaration
[-Werror=lto-type-mismatch]
char operator[] (size_t x);
src/UTF8Utils.cpp:148: note: implicit this pointer type mismatch
include/toolbox/UTF8Utils.h:23: note: type ‘struct UTF8Char’ itself violates
the C++ One Definition Rule
/remote/tmp/rnd-aqg/software_factory/bms_replication/mdw/Toolbox/18-0-0-48/include/toolbox/UTF8Utils.h:22:
note: the incompatible type is defined here
class TOOLBOX_EXPORT UTF8Char
src/UTF8Utils.cpp:148: note: ‘operator[]’ was previously declared here
src/UTF8Utils.cpp:148: note: code may be misoptimized unless
-fno-strict-aliasing is used
The problem here is that I mixed our own version of a library named "Toolbox"
from version 18-0-0-56 and 18-0-0-48 which are incompatible. I need to rebuild
the .o which is using version 18-0-0-48 as given in the error, however I have
no idea which libraries is that, and I have hundreds of them, which
unfortunately I can't rebuild massively easily.
So if the location in LTO mode could print something like:
/path/to/wrong/lib.a(name_of_o_file.o):/remote/tmp/rnd-aqg/software_factory/bms_replication/mdw/Toolbox/18-0-0-48/include/toolbox/UTF8Utils.h:22:
note: the incompatible type is defined here
class TOOLBOX_EXPORT UTF8Char
that would help identifying which files need rebuilding.
Cheers,
Romain
