I came across a "gotcha" whilst trying to test the static
implementation of libgfortran on PPC64-apple-darwin8.
Thanks to Tobias B for pointing me at 99% of the solution.
Probably the number of affected systems is small ;) - but, FWIW,
here's HOWTO and a fix.
-----
If you host on {powerpc, i686}-apple-darwin8 and you want to static
link (or check libgfortran) -m64 for PPC64 then this applies to you.
There is an incompatibility [presumably in ld64] between the default
debug symbol generation (stabs) and what's required
for linking/checking PPC64 on darwin8 ... this incompatibility "is
not going to be fixed".
The specific crunch is that every -O3 torture test is compiled with -g
=> in gfortran this causes every -O3 torture test to fail when
checking -m64.
----
The solution is to build the required code with -gdwarf-2,
unfortunately the "-g" flag is hard-coded in a couple of relevant
places:
(a) in "fortran-torture.exp" and in "gcc-dg.exp" (which is included
in gfortran-dg.exp)
[ the change to gcc-dg.exp makes this non-local to gfortran ]
(b) in the top level configure (as a default C/CXX/FLAGS_FOR_TARGET).
The minimum change work-around is this:
1/ configure/make gcc with CFLAGS_FOR_TARGET = "-02 -gdwarf-2 -
pipe" (and CXXFLAGS_FOR_TARGET the same)
2/ apply the following :
Index: gcc/testsuite/lib/gcc-dg.exp
===================================================================
--- gcc/testsuite/lib/gcc-dg.exp (revision 136861)
+++ gcc/testsuite/lib/gcc-dg.exp (working copy)
@@ -48,9 +48,15 @@
{ -O2 } \
{ -O3 -fomit-frame-pointer } \
{ -O3 -fomit-frame-pointer -funroll-loops } \
- { -O3 -fomit-frame-pointer -funroll-all-loops -finline-
functions } \
- { -O3 -g } \
- { -Os } ]
+ { -O3 -fomit-frame-pointer -funroll-all-loops -finline-
functions } ]
+
+ if { [istarget "*-*-darwin8"] } {
+ lappend DG_TORTURE_OPTIONS { -O3 -gdwarf-2 }
+ } else {
+ lappend DG_TORTURE_OPTIONS { -O3 -g }
+ }
+
+ lappend DG_TORTURE_OPTIONS { -Os }
}
global GCC_UNDER_TEST
Index: gcc/testsuite/lib/fortran-torture.exp
===================================================================
--- gcc/testsuite/lib/fortran-torture.exp (revision 136861)
+++ gcc/testsuite/lib/fortran-torture.exp (working copy)
@@ -73,9 +73,16 @@
{ -O2 } \
{ -O2 -fomit-frame-pointer -finline-functions } \
{ -O2 -fomit-frame-pointer -finline-functions -funroll-
loops } \
- { -O2 -fbounds-check } \
- { -O3 -g } \
- { -Os }
+ { -O2 -fbounds-check }
+
+ if { [istarget "*-*-darwin8"] } {
+ lappend options { -O3 -gdwarf-2 }
+ } else {
+ lappend options { -O3 -g }
+ }
+
+ lappend options { -Os }
+
if { $test_tree_vectorize } {
lappend options $vectorizer_options
}
*************************************
COMPARISONs of make check-host with and without the changes
This is on darwin 8.11.0
*************************************
make check-host (default, m32)
one extra pass, no regressions
*************************************
g++
-----
no change
gcc
-----
one extra pass from using dwarf-2
FAIL: gcc.dg/pch/save-temps-1.c -O3 -g assembly comparison
PASS: gcc.dg/pch/save-temps-1.c -O3 -gdwarf-2 assembly comparison
gfortran
----------
no change
obj-c++
----------
no change
obj-c
------
no change
*************************************
make check-host (m64) RUNTESTFLAGS="--target_board=unix/-m64"
69 extra passes, no regressions
*************************************
g++
------
one extra pass from using dwarf-2
FAIL: g++.old-deja/g++.eh/badalloc1.C execution test (-g)
PASS: g++.old-deja/g++.eh/badalloc1.C execution test (-gdwarf-2)
gcc
-----
one extra pass from using dwarf-2
FAIL: gcc.dg/pch/save-temps-1.c -O3 -g assembly comparison
PASS: gcc.dg/pch/save-temps-1.c -O3 -gdwarf-2 assembly comparison
gfortran (every test with -O3 -g fails )
----------
67 extra passes using -gdwarf-2
=== gfortran Summary (-g) ===
# of expected passes 26196
# of unexpected failures 85
# of expected failures 46
# of unsupported tests 59
/Volumes/SwapScratch/OS-source/gcc-44-build/n2n/gcc/testsuite/
gfortran/../../gfortran version 4.4.0 20080612 (experimental) (GCC)
=== gfortran Summary (-gdwarf-2) ===
# of expected passes 26263
# of unexpected failures 18
# of expected failures 46
# of unsupported tests 59
/Volumes/SwapScratch/OS-source/gcc-44-build/n2n/gcc/testsuite/
gfortran/../../gfortran version 4.4.0 20080612 (experimental) (GCC)
obj-c++
----------
no change
obj-c
------
no change
----
I guess, there's one residual puzzle to me; from the doc. I'd
understand that the -O3 optimizations are in the back end and therefore
common to all the tools. However, this problem only really shows up
to any significant extent with gfortran.
ttfn,
Iain
