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<== Date ==> <== Thread ==>
Subject: AW: EPICS 7 and VxWorks 6.9 for PPC604?
From: "Zimoch Dirk \(PSI\) via Core-talk" <core-talk at aps.anl.gov>
To: Michael Davidsaver <mdavidsaver at gmail.com>
Cc: "core-talk at aps.anl.gov" <core-talk at aps.anl.gov>
Date: Fri, 5 Jun 2020 07:59:06 +0000 
I don't know it this option is a vxWorks special option.
The name has changed over time. It was -mno-implicit-fp for gcc2 and 3 and is -fno-implicit-fp from gcc 4 on.

The WindRiver gcc manual says:
-fno-implicit-fp
By default, the compiler is free to use floating-point registers for
temporary values and integer computations, even when a function does
not explicitly use floating-point types.  fno-implicit-fp
prevents this, only allowing floating-point registers to be used in
functions that explicitly use floating-point types.  This option also
prevents inlining of functions that use floating-point types into
functions that do not use floating-point types.

At a few locations, they recommend this option.


> -----Ursprüngliche Nachricht-----
> Von: Michael Davidsaver <mdavidsaver at gmail.com>
> Gesendet: Donnerstag, 4. Juni 2020 15:30
> An: Zimoch Dirk (PSI) <dirk.zimoch at psi.ch>
> Cc: core-talk at aps.anl.gov
> Betreff: Re: EPICS 7 and VxWorks 6.9 for PPC604?
> 
> On 6/4/20 6:10 AM, Zimoch Dirk (PSI) via Core-talk wrote:
> > The problem seems to be that -fno-implicit-fp forbids to inline floating point
> functions into non-floating point
> > functions. In case of expire, the function uses no float/double explicitly:
> 
> I had wondered about that option.  It doesn't appear in the gcc docs.
> I guess it is a vxworks patch?
> 
> https://gcc.gnu.org/onlinedocs/gcc-4.3.6/gcc/Option-Summary.html#Option-
> Summary
> 
> > epicsTimerNotify::expireStatus timerForOldFdmgr::expire ( const epicsTime & )
> > {
> >     (*this->pFunc) (this->pParam);
> >     return noRestart;
> > }
> >
> > But epicsTimerNotify::expireStatus is a class containing a double. As the error
> happens at the closing } it probably
> > inlining the implicit operator= of the return value.
> >
> >
> > What I did now to solve the problem is to remove -fno-implicit-fp from
> ARCH_DEP_CFLAGS (which is used for C and C++) and
> > to add it to CODE_CFLAGS, which is used for C but not for C++. This is under
> the assumption that interrupt handlers are
> > written in C, not C++. But this does not cover extern "C" ISRs in C++.
> >
> > Maybe using __attribute__((optimize ("-fno-implicit-fp"))) or #pragma GCC ("-
> fno-implicit-fp") would be a better choice
> > to treat ISRs, but unfortunately both are not understood by the VxWorks 6.9
> compiler. At least it warns: "'optimize'
> > attribute directive ignored".
> >
> >
> > On Thu, 2020-06-04 at 09:24 +0000, Zimoch Dirk (PSI) via Core-talk wrote:
> >> It was on TechTalk in 2014 already: https://epics.anl.gov/tech-
> talk/2014/msg01579.php
> >>
> >> On Thu, 2020-06-04 at 08:55 +0000, Zimoch Dirk (PSI) via Core-talk wrote:
> >>> I found that the option -fno-implicit-fp causes the problem. When adding it
> to the generic ppc32 configuration, I get
> >>> the same "unable to find a register to spill in class 'FLOAT_REGS'" error
> unless I add -fno-expensive-optimizations as
> >>> well.
> >>>
> >>> I had originally added this option when I ran into strange run-time errors
> because an interrupt handler of some driver
> >>> had used floating point registers without being asked to do so for moving
> "long long" values. As the floating point
> >>> registers are not saved when entering interrupt mode, bad things happened
> to the interrupted thread.
> >>>
> >>>
> >>> On Wed, 2020-06-03 at 17:51 +0000, Johnson, Andrew N. wrote:
> >>>> I suspect that the CPU-specific code in gcc for the ppc604 target is older
> than for the ppc32 target and can’t cope with newer constructs, we’ve had
> similar issues before. That’s why I really want to encourage you try the ppc32
> targets, I don’t think they will show these errors at all and switching will save
> you time investigating the problems.
> >>>>
> >>>> - Andrew
> >>>>
> >>>> On Jun 3, 2020, at 12:30 PM, Zimoch Dirk (PSI) via Core-talk <core-
> talk at aps.anl.gov> wrote:
> >>>>> 3 files have problems implementing the pure virtual function
> epicsTimerNotify::expire(): fdmgr.cc line 152, epicsTime.cpp line 62 and
> epicsTimerTest.cpp line 319. What helps is -O1 or -no-expensive-optimizations.
> >>>>>
> >>>>> As I expect problems with any code that implements expire() I have now
> added 'CXXFLAGS += -fno-expensive-optimizations' to the general options for
> that architecture, not only for the 3 failing files.
> >>>>>
> >>>>> This does not yet solve the problem with typeCast.h.
> >>>>>
> >>>>> More tests tomorrow.
> >>>>>
> >>>>>> -----Ursprüngliche Nachricht-----
> >>>>>> Von: Michael Davidsaver <mdavidsaver at gmail.com>
> >>>>>> Gesendet: Mittwoch, 3. Juni 2020 18:48
> >>>>>> An: Zimoch Dirk (PSI) <dirk.zimoch at psi.ch>; 'core-talk at aps.anl.gov'
> <core-
> >>>>>> talk at aps.anl.gov>
> >>>>>> Betreff: Re: AW: EPICS 7 and VxWorks 6.9 for PPC604?
> >>>>>>
> >>>>>> On 6/3/20 8:31 AM, Zimoch Dirk (PSI) wrote:
> >>>>>>> I will try the selective -fno-inline ...
> >>>>>>
> >>>>>>
> >>>>>> If vxworks 6.7 had gcc 4.1 then the threshold for using
> >>>>>> __attribute__((always_inline)) is now being crossed.
> >>>>>>
> >>>>>> https://github.com/epics-
> >>>>>>
> base/pvDataCPP/blob/0fa927afa7d92f490f92eb4906e27046080309e2/src/misc
> >>>>>> /pv/templateMeta.h#L15-L16
> >>>>>>
> >>>>>>>> -----Ursprüngliche Nachricht-----
> >>>>>>>> Von: Zimoch Dirk (PSI)
> >>>>>>>> Gesendet: Mittwoch, 3. Juni 2020 17:30
> >>>>>>>> An: 'Michael Davidsaver' <mdavidsaver at gmail.com>; 'core-
> >>>>>>
> >>>>>>  talk at aps.anl.gov'
> >>>>>>>> <core-talk at aps.anl.gov>
> >>>>>>>> Betreff: AW: EPICS 7 and VxWorks 6.9 for PPC604?
> >>>>>>>>
> >>>>>>>> It's gcc 4.3.3.
> >>>>>>>>
> >>>>>>>> Using -O0 (as used to fix bug 1702298) in helps for fdmgr.cpp but not
> for
> >>>>>>>> typeCast.h.
> >>>>>>>>
> >>>>>>>>> -----Ursprüngliche Nachricht-----
> >>>>>>>>> Von: Michael Davidsaver <mdavidsaver at gmail.com>
> >>>>>>>>> Gesendet: Mittwoch, 3. Juni 2020 17:13
> >>>>>>>>> An: Zimoch Dirk (PSI) <dirk.zimoch at psi.ch>; 'core-talk at aps.anl.gov'
> <core-
> >>>>>>>>> talk at aps.anl.gov>
> >>>>>>>>> Betreff: Re: EPICS 7 and VxWorks 6.9 for PPC604?
> >>>>>>>>>
> >>>>>>>>> For those of us who aren't so familiar with vxworks, which GCC
> version(s)
> >>>>>>
> >>>>>>  are
> >>>>>>>>> involved.
> >>>>>>>>>
> >>>>>>>>> You may remember https://bugs.launchpad.net/epics-
> base/+bug/1702298
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> On 6/3/20 8:04 AM, Zimoch Dirk (PSI) via Core-talk wrote:
> >>>>>>>>>> Has anyone already compiled EPICS 7 for VxWorks 6.9 for PPC604?
> >>>>>>>>>> I have problems:
> >>>>>>>>>>
> >>>>>>>>>> With -O2 it fails here:
> >>>>>>>>>>
> >>>>>>>>>> ../fdmgr/fdmgr.cpp: In member function 'virtual
> >>>>>>>>>
> >>>>>>>>>  epicsTimerNotify::expireStatus timerForOldFdmgr::expire(const
> >>>>>>
> >>>>>>  epicsTime&)':
> >>>>>>>>>> ../fdmgr/fdmgr.cpp:152: error: unable to find a register to spill in
> class
> >>>>>>>>>
> >>>>>>>>>  'FLOAT_REGS'
> >>>>>>>>>> ../fdmgr/fdmgr.cpp:152: error: this is the insn:
> >>>>>>>>>> (insn:HI 16 15 17 2 ../fdmgr/fdmgr.cpp:151 (set (reg:DF 126 [
> >>>>>>
> >>>>>>  D.11913.delay
> >>>>>>>> ])
> >>>>>>>>>>        (mem/s/j/c:DF (plus:SI (reg/f:SI 113 sfp)
> >>>>>>>>>>                (const_int 8 [0x8])) [0 D.11913.delay+0 S8 A64])) 336
> >>>>>>>>>
> >>>>>>>>>  {*movdf_hardfloat32} (expr_list:REG_EQUIV (mem/s/j/c:DF (plus:SI
> (reg/f:SI
> >>>>>>>>
> >>>>>>>>  113
> >>>>>>>>> sfp)
> >>>>>>>>>>                (const_int 8 [0x8])) [0 D.11913.delay+0 S8 A64])
> >>>>>>>>>>        (nil)))
> >>>>>>>>>> ../fdmgr/fdmgr.cpp:152: confused by earlier errors, bailing out
> >>>>>>>>>>
> >>>>>>>>>> With -O1 (or lower) it comliles the above but then fails here:
> >>>>>>>>>>
> >>>>>>>>>> ../../src/misc/pv/typeCast.h: In function
> >>>>>>>>
> >>>>>>>>  'void<unnamed>::castVTyped(size_t,
> >>>>>>>>> void*, const void*) [with TO = std::basic_string<char,
> std::char_traits<char>,
> >>>>>>>>> std::allocator<char> >, FROM = float]':
> >>>>>>>>>> ../../src/misc/pv/typeCast.h:195: sorry, unimplemented: inlining
> failed in
> >>>>>>
> >>>>>>  call
> >>>>>>>>> to 'TO epics::pvData::castUnsafe(const FROM&) [with TO =
> >>>>>>>>> std::basic_string<char, std::char_traits<char>, std::allocator<char>
> >, FROM
> >>>>>>
> >>>>>>  =
> >>>>>>>>> float]': recursive inlining
> >>>>>>>>>> ../../src/misc/typeCast.cpp:38: sorry, unimplemented: called from
> here
> >>>>>>>>>>
> >>>>>>>>>> At least the compiler is "sorry".  I feel much better.
> >>>>>>>>>>
> >>>>>>>>>> BTW: VxWorks 6.7 has no such problems.
> >>>>>>>>>>
> >>>>>>>>>> Dirk
> >>>>>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>
> >>>>>
> >>>>
> >>>> --
> >>>> Complexity comes for free, simplicity you have to work for.
> >>>>
References:
EPICS 7 and VxWorks 6.9 for PPC604? Zimoch Dirk (PSI) via Core-talk
Re: EPICS 7 and VxWorks 6.9 for PPC604? Michael Davidsaver via Core-talk
AW: EPICS 7 and VxWorks 6.9 for PPC604? Zimoch Dirk (PSI) via Core-talk
AW: EPICS 7 and VxWorks 6.9 for PPC604? Zimoch Dirk (PSI) via Core-talk
Re: AW: EPICS 7 and VxWorks 6.9 for PPC604? Michael Davidsaver via Core-talk
AW: AW: EPICS 7 and VxWorks 6.9 for PPC604? Zimoch Dirk (PSI) via Core-talk
Re: EPICS 7 and VxWorks 6.9 for PPC604? Johnson, Andrew N. via Core-talk
Re: EPICS 7 and VxWorks 6.9 for PPC604? Zimoch Dirk (PSI) via Core-talk
Re: EPICS 7 and VxWorks 6.9 for PPC604? Zimoch Dirk (PSI) via Core-talk
Re: EPICS 7 and VxWorks 6.9 for PPC604? Zimoch Dirk (PSI) via Core-talk
Re: EPICS 7 and VxWorks 6.9 for PPC604? Michael Davidsaver via Core-talk
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