ROOT does not compile with link-time optimizations (LTO) enabled

[amadio]

Full bug report is at https://bugs.gentoo.org/879323.

Important part of the build log is below.

/usr/bin/cmake -E copy_if_different /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/tutorials/tree/jets.C /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08_build/tutorials/tree/jets.C
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/zebra.f:767:72: error: type of <E2><80>-Werror=lto-type-mismatch][]]
  767 |      + ISTAT)
      |                                                                        ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/cernlib.c:107:6: note: ‘cfget_’ was previously declared here
  107 | void cfget_(int *lundes, int *medium, int *nwrec, int *nwtak, char *mbuf,
      |      ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/cernlib.c:107:6: note: code may be misoptimized unless ‘-fno-strict-aliasing’ is used
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/kernlib.f:398:72: error: type of <E2><80>-Werror=lto-type-mismatch][]]
  398 |       CFSTAT = CFSTATI (NAME, INFO, LGN)
      |                                                                        ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/cernlib.c:171:5: note: type mismatch in parameter 4
  171 | int cfstati_(char *fname, int *info, int *lgname)
      |     ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/cernlib.c:171:5: note: type ‘void’ should match type ‘long int’
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/cernlib.c:171:5: note: ‘cfstati_’ was previously declared here
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/kernlib.f:386:72: error: type of <E2><80>-Werror=lto-type-mismatch][]]
  386 |       CALL CFOPEI (LUNDES,MEDIUM,NWREC,NVMODE,NBUF,NAME,ISTAT,LGN)
      |                                                                        ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/cernlib.c:225:6: note: type mismatch in parameter 9
  225 | void cfopei_(int *lundes, int *medium, int *nwrec, int *mode, int *nbuf,
      |      ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/cernlib.c:225:6: note: type ‘void’ should match type ‘long int’
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/cernlib.c:225:6: note: ‘cfopei_’ was previously declared here
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/hbook.f:542:72: error: type of <E2><80>-Werror=lto-type-mismatch][]]
  542 |                CALL UCOPY2(IQ(LCID+ITAG1),IQ(LCID+32),NW)
      |                                                                        ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/kernlib.f:403:23: note: ‘ucopy2’ was previously declared here
  403 |       SUBROUTINE UCOPY2 (A,B,N)
      |                       ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/kernlib.f:403:23: note: code may be misoptimized unless ‘-fno-strict-aliasing’ is used
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/main/src/g2root.f:1581:72: error: type of <E2><80>-Werror=lto-type-mismatch][]]
 1581 |       CALL VZERO(JNAMES,20)
      |                                                                        ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/hbook.f:2184:72: error: type of <E2><80>-Werror=lto-type-mismatch][]]
 2184 |       CALL VZERO(I1,37)
      |                                                                        ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/kernlib.f:105:22: note: ‘vzero’ was previously declared here
  105 |       SUBROUTINE VZERO (A,N)
      |                      ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/kernlib.f:105:22: note: code may be misoptimized unless ‘-fno-strict-aliasing’ is used
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/hbook.f:1959:18: error: type of <E2><80>-Werror=lto-type-mismatch][]]
 1959 |       COMMON/PAWC/NWPAW,IXPAWC,IHDIV,IXHIGZ,IXKU,FENC(5),LMAIN,
      |                  ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/zebra.f:205:19: error: type of <E2><80>-Werror=lto-type-mismatch][]]
  205 |       COMMON /PAWC/  NWPAW,IXPAWC,IHBOOK,IXHIGZ,IXKU,IFENCE(5)
      |                   ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/main/src/g2root.f:278:18: note: ‘pawc’ was previously declared here
  278 |       common/pawc/paw(nwpaw)
      |                  ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/main/src/g2root.f:278:18: note: code may be misoptimized unless ‘-fno-strict-aliasing’ is used
[ 56%] Copying /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/tutorials/tree/ntuple1.C
/usr/bin/cmake -E copy_if_different /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/tutorials/tree/ntuple1.C /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08_build/tutorials/tree/ntuple1.C
[ 56%] Copying /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/tutorials/tree/parallelcoord.C
/usr/bin/cmake -E copy_if_different /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/tutorials/tree/parallelcoord.C /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08_build/tutorials/tree/parallelcoord.C
[ 56%] Copying /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/tutorials/tree/parallelcoordtrans.C
/usr/bin/cmake -E copy_if_different /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/tutorials/tree/parallelcoordtrans.C /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08_build/tutorials/tree/parallelcoordtrans.C
[ 56%] Copying /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/tutorials/tree/printSizes.C
/usr/bin/cmake -E copy_if_different /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/tutorials/tree/printSizes.C /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08_build/tutorials/tree/printSizes.C
lto1: some warnings being treated as errors
lto-wrapper: fatal error: /usr/bin/x86_64-pc-linux-gnu-gfortran returned 1 exit status
compilation terminated.
/usr/lib/gcc/x86_64-pc-linux-gnu/12/../../../../x86_64-pc-linux-gnu/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status

[couet]

I looked at the first error.

/usr/bin/cmake -E copy_if_different /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/tutorials/tree/jets.C /var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08_build/tutorials/tree/jets.C
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/zebra.f:767:72: error: type of <E2><80>-Werror=lto-type-mismatch][]]
  767 |      + ISTAT)
      |                                                                        ^
/var/tmp/portage/sci-physics/root-6.26.08/work/root-6.26.08/misc/minicern/src/cernlib.c:107:6: note: ‘cfget_’ was previously declared here
  107 | void cfget_(int *lundes, int *medium, int *nwrec, int *nwtak, char *mbuf,
      |      ^

I checked the code. Seems to me it is correct. In the c part, istat is declared as int *istat. which is normal because FORTRAN always passes by address. and in the FORTRAN part, we have ISTAT which is an integer as it starts with I.

[amadio]

I think the problem might actually be due to the char *mbuf that comes before. That looks like it's treated as int by Fortran too, no? The type that is mismatched is the type of the function, if I understood the error correctly.

[eguiraud]

Note that there is also a problem with LLVM and LTO: #11135

[ferdymercury]

asan also reports some errors in these files, but on other lines: #18234 (comment)

[bellenot]

Closing since building with LTO is not supported, as mentioned here: #11135