https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93115
Bug ID: 93115
Summary: gcc fails to emit inline function on llvm-roc project:
-O1 -fPIC -fdevirtualize -fdevirtualize-speculatively
-fipa-cp -fipa-cp-clone -fvisibility-inlines-hidden
Product: gcc
Version: 9.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ipa
Assignee: unassigned at gcc dot gnu.org
Reporter: slyfox at inbox dot ru
CC: marxin at gcc dot gnu.org
Target Milestone: ---
Created attachment 47577
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47577&action=edit
bug.cpp
Original build failure found and diagnosed by Jan Ziak in
https://bugs.gentoo.org/704252. There gcc-9.2.0 fails to link an LLVM library
due to missing inline function definition.
It looks like two main triggers are -fdevirtualize-speculatively and
-fipa-cp-clone trick gcc into not emitting inline function body. And only
presence of -fvisibility-inlines-hidden makes it noticeable.
I've managed to reproduce it on gcc-master and on gcc-9.2.0:
This works:
$ g++-9.2.0 -fPIC -O1 -fdevirtualize -fdevirtualize-speculatively -fipa-cp
-fipa-cp-clone -fPIC -shared -o libbug.so bug.cpp -DLIB_FILE
$ g++-9.2.0 -fPIC -O1 -fdevirtualize -fdevirtualize-speculatively -fipa-cp
-fipa-cp-clone -o main bug.cpp -DMAIN_FILE -L. -lbug
This fails:
g++-9.2.0 -fPIC -O1 -fdevirtualize -fdevirtualize-speculatively -fipa-cp
-fipa-cp-clone -fvisibility-inlines-hidden -fPIC -shared -o libbug.so bug.cpp
-DLIB_FILE
g++-9.2.0 -fPIC -O1 -fdevirtualize -fdevirtualize-speculatively -fipa-cp
-fipa-cp-clone -fvisibility-inlines-hidden -o main bug.cpp
-DMAIN_FILE -L. -lbug
/usr/bin/ld: /tmp/ccQYknNI.o: in function `p()':
bug.cpp:(.text+0x25): undefined reference to `m::av() const'
/usr/bin/ld: bug.cpp:(.text+0x4e): undefined reference to `m::av() const'
collect2: error: ld returned 1 exit status
Note: we build both library libbug.so and main executables to observe that main
lacks definition of inlinable 'm::av()'.
