Date: Wed, 7 Aug 2019 15:27:33 -0700 From: Mark Millard <marklmi@yahoo.com> To: Brooks Davis <brooks@freebsd.org> Cc: freebsd-toolchain@freebsd.org, freebsd-ports@freebsd.org, freebsd-ppc@freebsd.org Subject: Re: devel/llvm90 requires math/z3 first; building math/z3 requires a c++ toolchain be in place Message-ID: <B77A3A6D-FECE-441C-A0B3-88F427DA4B84@yahoo.com> In-Reply-To: <EEF22C3D-A4C0-4199-BABE-61982C80A283@yahoo.com> References: <20190806165525.GC94703@spindle.one-eyed-alien.net> <2A88AADC-8ED0-4FFD-85A8-34C0186D5D4F@yahoo.com> <20190807020826.GH94703@spindle.one-eyed-alien.net> <602EEB6C-D0B0-4EFB-AB0E-BE98FF1C4D90@yahoo.com> <086C99B8-1289-4D81-AAF5-85FB0AE70B7C@yahoo.com> <20190807171714.GI94703@spindle.one-eyed-alien.net> <20190807180244.GJ94703@spindle.one-eyed-alien.net> <4FF9540B-E1FE-4947-8E45-8D4FB57A7E34@yahoo.com> <20190807195613.GK94703@spindle.one-eyed-alien.net> <68CDAEA5-73D8-40FB-A22F-CC3B357FA992@yahoo.com> <20190807205846.GM94703@spindle.one-eyed-alien.net> <EEF22C3D-A4C0-4199-BABE-61982C80A283@yahoo.com>
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[I found that the vintage of cmake matters: 3.12 and
earlier work differently. Details later.]
On 2019-Aug-7, at 14:37, Mark Millard <marklm at yahoo.com> wrote:
> On 2019-Aug-7, at 13:58, Brooks Davis <brooks at freebsd.org> wrote:
>=20
>> On Wed, Aug 07, 2019 at 01:42:26PM -0700, Mark Millard wrote:
>>>=20
>>>=20
>>> On 2019-Aug-7, at 12:56, Brooks Davis <brooks at freebsd.org> wrote:
>>>=20
>>>> On Wed, Aug 07, 2019 at 11:55:04AM -0700, Mark Millard wrote:
>>>>>=20
>>>>>=20
>>>>> On 2019-Aug-7, at 11:02, Brooks Davis <brooks at freebsd.org> =
wrote:
>>>>>=20
>>>>>> On Wed, Aug 07, 2019 at 05:17:14PM +0000, Brooks Davis wrote:
>>>>>>> On Tue, Aug 06, 2019 at 09:22:52PM -0700, Mark Millard wrote:
>>>>>>>> [I found something known to be missing in the
>>>>>>>> in at least some versions of
>>>>>>>> llvm/cmake/modules/CrossCompile.cmake that messes
>>>>>>>> up the overall handling of LLVM_ENABLE_Z3_SOLVER .]
>>>>>>>>=20
>>>>>>>> On 2019-Aug-6, at 20:23, Mark Millard <marklmi at yahoo.com> =
wrote:
>>>>>>>>=20
>>>>>>>>=20
>>>>>>>>=20
>>>>>>>>> On 2019-Aug-6, at 19:08, Brooks Davis <brooks at freebsd.org> =
wrote:
>>>>>>>>>=20
>>>>>>>>>> On Tue, Aug 06, 2019 at 05:59:21PM -0700, Mark Millard wrote:
>>>>>>>>>>>=20
>>>>>>>>>>>=20
>>>>>>>>>>> On 2019-Aug-6, at 09:55, Brooks Davis <brooks at =
freebsd.org> wrote:
>>>>>>>>>>>=20
>>>>>>>>>>>> I'd prefer to disable this dependency. There's a knob that =
worked in
>>>>>>>>>>>> the 8.0 timeframe, but the lit build now autodetects z3 =
when it is
>>>>>>>>>>>> present and I've failed to find a knob to disable it. For =
now, the easy
>>>>>>>>>>>> workaround is probably to disable options LIT. We could =
make that the
>>>>>>>>>>>> default on non-LLVM platforms is that makes sense.
>>>>>>>>>>>>=20
>>>>>>>>>>>> -- Brooks
>>>>>>>>>>>=20
>>>>>>>>>>> Okay.
>>>>>>>>>>>=20
>>>>>>>>>>> poudriere-devel automatically built math/z3 because
>>>>>>>>>>> I'd indicated to build devel/llvm90 . math/z3 was not
>>>>>>>>>>> previously built: I've never had other use of it. So
>>>>>>>>>>> my context was not one of an implicit autodetect.
>>>>>>>>>>=20
>>>>>>>>>> The dependency is there because if z3 is installed then the =
package
>>>>>>>>>> that is built depends on z3. Thus I had not choice but to =
add a z3
>>>>>>>>>> dependency until I find a way to turn it off. You can either =
help find
>>>>>>>>>> a way to disable z3 detection in the cmake infrastructure or =
turn off
>>>>>>>>>> LIT. I don't have any use for reports on the effects of =
commenting out
>>>>>>>>>> the DEPENDS line. I know what that does.
>>>>>>>>>=20
>>>>>>>>>=20
>>>>>>>>> I hope this helps. (I'm not a cmake expert.)
>>>>>>>>>=20
>>>>>>>>> llvm-9.0.0rc1.src/lib/Support/Z3Solver.cpp does:
>>>>>>>>>=20
>>>>>>>>> #if LLVM_WITH_Z3
>>>>>>>>>=20
>>>>>>>>> #include <z3.h>
>>>>>>>>>=20
>>>>>>>>> namespace {
>>>>>>>>> . . .
>>>>>>>>> } // end anonymous namespace
>>>>>>>>>=20
>>>>>>>>> #endif
>>>>>>>>>=20
>>>>>>>>> llvm::SMTSolverRef llvm::CreateZ3Solver() {
>>>>>>>>> #if LLVM_WITH_Z3
>>>>>>>>> return llvm::make_unique<Z3Solver>();
>>>>>>>>> #else
>>>>>>>>> llvm::report_fatal_error("LLVM was not compiled with Z3 =
support, rebuild "
>>>>>>>>> "with -DLLVM_ENABLE_Z3_SOLVER=3DON",
>>>>>>>>> false);
>>>>>>>>> return nullptr;
>>>>>>>>> #endif
>>>>>>>>> }
>>>>>>>>>=20
>>>>>>>>> (There are other places LLVM_WITH_Z3 is used but the
>>>>>>>>> above is suggestive.)
>>>>>>>>>=20
>>>>>>>>> Working backwards finds that:
>>>>>>>>>=20
>>>>>>>>> =
/wrkdirs/usr/ports/devel/llvm90/work/llvm-9.0.0rc1.src/CMakeLists.txt
>>>>>>>>>=20
>>>>>>>>> shows LLVM_WITH_Z3 being conditionally set to 1 via . . .
>>>>>>>>>=20
>>>>>>>>> set(LLVM_Z3_INSTALL_DIR "" CACHE STRING "Install directory of =
the Z3 solver.")
>>>>>>>>>=20
>>>>>>>>> find_package(Z3 4.7.1)
>>>>>>>>>=20
>>>>>>>>> if (LLVM_Z3_INSTALL_DIR)
>>>>>>>>> if (NOT Z3_FOUND)
>>>>>>>>> message(FATAL_ERROR "Z3 >=3D 4.7.1 has not been found in =
LLVM_Z3_INSTALL_DIR: ${LLVM_Z3_INSTALL_DIR}.")
>>>>>>>>> endif()
>>>>>>>>> endif()
>>>>>>>>>=20
>>>>>>>>> set(LLVM_ENABLE_Z3_SOLVER_DEFAULT "${Z3_FOUND}")
>>>>>>>>>=20
>>>>>>>>> option(LLVM_ENABLE_Z3_SOLVER
>>>>>>>>> "Enable Support for the Z3 constraint solver in LLVM."
>>>>>>>>> ${LLVM_ENABLE_Z3_SOLVER_DEFAULT}
>>>>>>>>> )
>>>>>>>>>=20
>>>>>>>>> if (LLVM_ENABLE_Z3_SOLVER)
>>>>>>>>> if (NOT Z3_FOUND)
>>>>>>>>> message(FATAL_ERROR "LLVM_ENABLE_Z3_SOLVER cannot be enabled =
when Z3 is not available.")
>>>>>>>>> endif()
>>>>>>>>>=20
>>>>>>>>> set(LLVM_WITH_Z3 1)
>>>>>>>>> endif()
>>>>>>>>>=20
>>>>>>>>> if( LLVM_TARGETS_TO_BUILD STREQUAL "all" )
>>>>>>>>> set( LLVM_TARGETS_TO_BUILD ${LLVM_ALL_TARGETS} )
>>>>>>>>> endif()
>>>>>>>>>=20
>>>>>>>>>=20
>>>>>>>>> If I read that correctly, LLVM_ENABLE_Z3_SOLVER set directly
>>>>>>>>> appears to override the default (that tracks if z3 was found).
>>>>>>>>=20
>>>>>>>> I saw a reference to:
>>>>>>>>=20
>>>>>>>> diff --git a/llvm/cmake/modules/CrossCompile.cmake =
b/llvm/cmake/modules/CrossCompile.cmake
>>>>>>>> index bc3b210f018..0c30b88f80f 100644
>>>>>>>> --- a/llvm/cmake/modules/CrossCompile.cmake
>>>>>>>> +++ b/llvm/cmake/modules/CrossCompile.cmake
>>>>>>>> @@ -53,6 +53,7 @@ function(llvm_create_cross_target_internal =
target_name toolchain buildtype)
>>>>>>>> -DLLVM_DEFAULT_TARGET_TRIPLE=3D"${TARGET_TRIPLE}"
>>>>>>>> -DLLVM_TARGET_ARCH=3D"${LLVM_TARGET_ARCH}"
>>>>>>>> =
-DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=3D"${LLVM_TEMPORARILY_ALLOW_OLD_TOO=
LCHAIN}"
>>>>>>>> + -DLLVM_ENABLE_Z3_SOLVER=3D"${LLVM_ENABLE_Z3_SOLVER}"
>>>>>>>> ${build_type_flags} ${linker_flag} ${external_clang_dir}
>>>>>>>> WORKING_DIRECTORY ${LLVM_${target_name}_BUILD}
>>>>>>>> DEPENDS CREATE_LLVM_${target_name}
>>>>>>>>=20
>>>>>>>> in https://reviews.llvm.org/D54978 on Feb 12 2019, 5:41 PM
>>>>>>>> and it had the comment:
>>>>>>>>=20
>>>>>>>> QUOTE
>>>>>>>> Independent of the rest of the discussion, this patch should be =
part of the reland, to make sure that explicitly turning off Z3 works =
reliably. Thanks for coming up with that, and thanks everyone for the =
good discussion here :)
>>>>>>>> END QUOTE
>>>>>>>>=20
>>>>>>>> This apparently fixes a sub-cmake not respecting the
>>>>>>>> LLVM_ENABLE_Z3_SOLVER setting in the parent cmake.
>>>>>>>> (The overall review earlier describes the sub-cmake
>>>>>>>> not doing the right thing.)
>>>>>>>=20
>>>>>>> Thanks for digging this up. Unfortunately, this doesn't seem to =
have
>>>>>>> solved the problem. With this patch applied I still get this if =
I have
>>>>>>> z3 installed on the system and no LIB_DEPENDS line:
>>>>>>>=20
>>>>>>> Error: /usr/local/bin/FileCheck90 is linked to =
/usr/local/lib/libz3.so.0
>>>>>>> from math/z3 but it is not declared as a dependency
>>>>>>> Warning: you need LIB_DEPENDS+=3Dlibz3.so:math/z3
>>>>>>>=20
>>>>>>> I've generally observed that the portions of the system that =
cover lit
>>>>>>> (which includes FileCheck) aren't very well behaved.
>>>>>>=20
>>>>>> I've filed https://bugs.llvm.org/show_bug.cgi?id=3D42921 =
upstream,
>>>>>> hopefully someone who understand this part of the cmake system =
will help
>>>>>> us out.
>>>>>=20
>>>>> You mentioned applying the patch but not also
>>>>> setting:
>>>>>=20
>>>>> LLVM_ENABLE_Z3_SOLVER:BOOL=3DOFF
>>>>>=20
>>>>> with either:
>>>>>=20
>>>>> -D LLVM_ENABLE_Z3_SOLVER:BOOL=3DOFF
>>>>>=20
>>>>> on the command line or some line early in CMakeCache.txt .
>>>>> (Actually, I had to look around to know to say those
>>>>> specifics of what it means to have already initialized
>>>>> LLVM_ENABLE_Z3_SOLVER .)
>>>>>=20
>>>>> =46rom what I see, taking the initial assignment via =
CMakeCache.txt
>>>>> after it is initialized seems to be a common technique of =
controlling
>>>>> the configuration.
>>>>>=20
>>>>> Taking from an example from web of a CMakeCache.txt . . .
>>>>>=20
>>>>>=20
>>>>> # This is the CMakeCache file.
>>>>> # For build in directory: [edited out]
>>>>> # It was generated by CMake: =
/Applications/CMake.app/Contents/bin/cmake
>>>>> # You can edit this file to change values found and used by cmake.
>>>>> # If you do not want to change any of the values, simply exit the =
editor.
>>>>> # If you do want to change a value, simply edit, save, and exit =
the editor.
>>>>> # The syntax for the file is as follows:
>>>>> # KEY:TYPE=3DVALUE
>>>>> # KEY is the name of a variable in the cache.
>>>>> # TYPE is a hint to GUIs for the type of VALUE, DO NOT EDIT TYPE!.
>>>>> # VALUE is the current value for the KEY.
>>>>>=20
>>>>> ########################
>>>>> # EXTERNAL cache entries
>>>>> ########################
>>>>>=20
>>>>> //Build a 32 bit version of the library.
>>>>> BENCHMARK_BUILD_32_BITS:BOOL=3DOFF
>>>>>=20
>>>>> . . . (lots omitted) . . .
>>>>>=20
>>>>>=20
>>>>> //Fail and stop if a warning is triggered.
>>>>> LLVM_ENABLE_WERROR:BOOL=3DOFF
>>>>>=20
>>>>> //Enable Support for the Z3 constraint solver in LLVM.
>>>>> LLVM_ENABLE_Z3_SOLVER:BOOL=3DOFF
>>>>>=20
>>>>> //Use zlib for compression/decompression if available.
>>>>> LLVM_ENABLE_ZLIB:BOOL=3DON
>>>>>=20
>>>>> . . . (lots more omitted) . . .
>>>>>=20
>>>>>=20
>>>>> The example already had the "LLVM_ENABLE_Z3_SOLVER:BOOL=3DOFF"
>>>>> line, I did not adjust it.
>>>>=20
>>>> Upstream spotted this error as well. I've hopefully committed a =
fix (of
>>>> course just as I committed I discovered I'd had the patch applied =
and it
>>>> shouldn't be needed so I'm now rebuilding again and will add the =
patch
>>>> if needed.)
>>>=20
>>> Just for my curiosity: which way are you
>>> initializing LLVM_ENABLE_Z3_SOLVER to OFF ?:
>>>=20
>>> A) Having -D LLVM_ENABLE_Z3_SOLVER:BOOL=3DOFF on the cmake command =
line?
>>> B) Having LLVM_ENABLE_Z3_SOLVER:BOOL=3DOFF in the CMakeCache.txt =
file?
>>> C) Something else (that I missed as a technique)?
>>=20
>> (A) via:
>>=20
>> CMAKE_ARGS+=3D -DLLVM_ENABLE_Z3_SOLVER=3DOFF
>=20
> Thanks.
>=20
> =46rom what I've seen the :BOOL part of the syntax should be used:
>=20
> CMAKE_ARGS+=3D -DLLVM_ENABLE_Z3_SOLVER:BOOL=3DOFF
>=20
> It is not a textual definition from what I gather and
> the intended type should be specified as well. (But
> I'm learning things as I go.)
I ran into the following issue for CMake 3.12 and earlier
(before 01 Dec 2018 07:37:57 according to freshports) . . .
QUOTE
option() honors normal variables.
The option() command is typically used to create a cache entry to allow =
users to set the option. However, there are cases in which a normal =
(non-cached) variable of the same name as the option may be defined by =
the project prior to calling the option() command. For example, a =
project that embeds another project as a subdirectory may want to =
hard-code options of the subproject to build the way it needs.
For historical reasons in CMake 3.12 and below the option() command =
removes a normal (non-cached) variable of the same name when:
=E2=80=A2 a cache entry of the specified name does not exist at =
all, or
=E2=80=A2 a cache entry of the specified name exists but has not =
been given a type (e.g. via -D<name>=3DON on the command line).
END QUOTE
So the setting of LLVM_ENABLE_Z3_SOLVER:BOOL=3DOFF will not work
for CMake 3.12 and before.
=3D=3D=3D
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)
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