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[[!tag open_issue_llvm]]

Here's what's to be done for maintaining [[/LLVM]].

Apart from the target-specific configuration machinery, there shouldn't be any
major differences within LLVM between the GNU/Hurd and GNU/Linux ports, for
example.  Especially all the compiler magic is all the same.

[[!toc levels=2]]


# [[General information|/llvm]]


## Rebuild of the Debian archive with clang

From [[!message-id "20120305195308.GA1904@zouish.org"]]:
<http://sylvestre.ledru.info/blog/sylvestre/2012/02/29/rebuild_of_the_debian_archive_with_clang>,
<http://clang.debian.net/>.


# [[Sources|source_repositories/llvm]]


# Configuration

<!--

For all of llvm, clang, compiler-rt, test-suite:

git checkout reviewed
git log --reverse --topo-order --pretty=fuller --stat=$COLUMNS,$COLUMNS -w -p -C --cc ..upstream/master
-i
/^commit |^merge:|^---$|hurd|gnu|linux|nacl|nptl|glibc|[^e]gs:|/proc

-->

Last reviewed up to the [[Git mirror's sources|source_repositories/llvm]]: llvm
6f7becfe23f38e8c28e9422d883263974058aeed (2013-03-24), clang
495cfa46300979642acde8d93a1f21c9291dac98 (2013-03-23), compiler-rt
a06fe9183fbffb78798a444da9bc3040fdd444aa (2013-03-23), test-suite
5a05572d268568fb15b48f374f9fc9f882adecd2 (2013-03-23).

  * <http://anonscm.debian.org/viewvc/pkg-llvm/llvm/trunk/debian/patches/>.

  * [low] Some more `PATH_MAX`/`MAXPATHLEN` things.

  * `gs:` usage

      * `lib/Target/X86/`, `test/CodeGen/X86/`, `test/MC/X86/`.

      * `tools/clang/`

            tools/clang/docs/LanguageExtensions.rst:          movl    %gs:(%eax), %eax
            tools/clang/test/Sema/asm.c:  asm volatile ("movb %%gs:%P2,%b0" : "=q"(b) : "0"(0), "i"(5L));

      * `compiler-rt` and `test-suite` not yet examined.

  * [low] Linuxisms

      * In some CMake files (`CMakeLists.txt`, for example).

      * `test/`, `unittests`, `tools/clang/test/`, `tools/clang/unittests/` not
        yet examined.

          * In clang's `test/Driver/` a lot of testing can be generalized from
            *Linux* to *GNU environment*, adding GNU/Hurd testing, too.

      * LLVM commit 98fbe27ac8f0766ea94b89b8c03418131b72bea4 `Support for
        HiPE-compatible code emission`

        Only relevant for `CallingConv::HiPE`.

            +  assert(ST->isTargetLinux() &&
            +         "HiPE prologue is only supported on Linux operating systems.");

      * `compiler-rt` and `test-suite` not yet examined.

  * `/proc` usage

      * `compiler-rt` and `test-suite` not yet examined.

  * `libc++` (not currently using)

    Some Hurd-porting work is said to have been done as Google Summer of Code
    2012 Debian project,
    <http://wiki.debian.org/SummerOfCode2012/StudentApplications/AndrejBelym>.

  * [[sanitizers|_san]]

    A lot of Linux-specific things.

  * IRC, OFTC, #debian-hurd, 2013-09-05:

        <gg0> how can this fix it on {kf,hurd}-i386?
          http://anonscm.debian.org/viewvc/pkg-llvm/llvm-toolchain/branches/3.3/debian/patches/libstdc%2B%2B-header-i386.diff?view=markup&sortby=date&pathrev=830
        <pinotree> what makes you think it does?
        <pinotree> it fixes #714890, which has nothing to do with hurd or
          kfreebsd
        <gg0> i simple wouldn't add a patch that fixes it on one i386 arch
          only, being aware there are others
        <pinotree> meet sylvestre

  * IRC, freenode, #hurd, 2013-09-05:

        <pinotree> tschwinge: iirc you were working on llvm/clang, weren't you?
        <tschwinge> pinotree: That's right.  I have patches to
          follow-up/rework.  Stalled at the moment, as you probably already
          guessed...  %-)
        <pinotree> tschwinge: <Sylvestre> by the way, pinotree if you have time
          for hurd stuff, I would be glad to have your help to port
          llvm-toolchain-3.3 to hurd. I am having some issues with threading
          aspects https://paste.debian.net/35466/
        <pinotree> he's the debian packager of llvm
        <tschwinge> That paste is for LLDB -- which I'd not assume to be in a
          shape usable for Hurd.
        <tschwinge> (I didn't look at it at all.)
        <pinotree> tschwinge: if you look at the latest llvm-toolchain-3.3
          debian source, there's a lldb-hurd.diff patch, which starts some
          include header dance


# Build

Here's a log of a LLVM build run; this is from our [[Git repository's
sources|source_repositories/llvm]], llvm
dc218fb6ae3241f4b66e9bf2c9d6352efecc0a14 (2013-03-24), clang
744290b5ecd48bddb4a6cf96d68cdc4a57e24e36 (2013-03-24), compiler-rt
a06fe9183fbffb78798a444da9bc3040fdd444aa (2013-03-23), test-suite
1821ab0ef1c73430705356fdfde3769460092382 (2013-03-24), run on
kepler.SCHWINGE and coulomb.SCHWINGE.

    $ export LC_ALL=C
    $ (cd ../Horace_Silver/ && ln -sfn ../../../clang/tschwinge/Hank_Mobley tools/clang)
    $ (cd ../Horace_Silver/ && ln -sfn ../../../compiler-rt/tschwinge/Doug_Watkins projects/compiler-rt)
    $ (cd ../Horace_Silver/ && ln -sfn ../../../test-suite/tschwinge/Art_Blakey projects/test-suite)
    $ ../Horace_Silver/configure --prefix="$PWD".install --enable-optimized SHELL=/bin/dash CC=gcc-4.7 CXX=g++-4.7 2>&1 | tee log_build
    $ make VERBOSE=1 2>&1 | tee log_build_

Different hosts may default to different shells and compiler versions; thus
harmonized.

Passing `--enable-debug-symbols`, the GNU/Hurd build on coulomb.SCHWINGE
terminates with a SIGBUS
when linking `Release+Debug+Asserts/bin/clang` (which is bigger than 500 MiB
for the corresponding GNU/Linux build).  Using `--enable-debug-symbols
--enable-shared`, the GNU/Hurd build hang after `make[1]: Leaving directory
[...]/tools/llvm-shlib`, after (successfully) linking
`Release+Debug+Asserts/lib/libLLVM-3.3svn.so` (which is bigger than 250 MiB for
the corresponding GNU/Linux build).  Also there is a separate
`--enable-debug-runtime`.

This takes up around 3.2 GiB, and needs roughly 1.5 h on kepler.SCHWINGE and
5.25 h on coulomb.SCHWINGE.

Configuring without `--enable-optimized` even crashes mighty darnassus,
probably because of too-big files when linking.  Configuring with
`--enable-optimized --enable-expensive-checks --disable-threads
--enable-debug-symbols --enable-debug-runtime` is fine.

<!--

    $ (make VERBOSE=1 && touch .go-install) 2>&1 | tee log_build_ && test -f .go-install && (make VERBOSE=1 install && touch .go-test) 2>&1 | tee log_install && test -f .go-test && { make -k VERBOSE=1 LIT_ARGS='-v --threads=1' check-all 2>&1 | tee log_test_check-all; make -k -C projects/test-suite/ 2>&1 | tee log_test_test-suite; }

    $ (PATH=$HOME/tmp/source/autoconf/AUTOCONF-2.60.build.install/bin:$HOME/tmp/source/automake/automake-1.9.6.build.install/bin:$HOME/tmp/source/libtool/release-1-5-22.build.install/bin:$PATH; ./AutoRegen.sh)

-->


## Analysis

    $ toolchain/logs/process llvm build

        -checking for mmap of files... yes
        +checking for mmap of files... no
         checking if /dev/zero is needed for mmap... no
        +configure: WARNING: mmap() of files required but not found

   Due to [[mmap_write-only]].

        +In file included from [...]/lib/Support/Process.cpp:85:0:
        +[...]/lib/Support/Unix/Process.inc: In function 'unsigned int getColumns(int)':
        +[...]/lib/Support/Unix/Process.inc:227:21: warning: enumeral and non-enumeral type in conditional expression [enabled by default]

           225    // Try to determine the width of the terminal.
           226    struct winsize ws;
           227    if (ioctl(FileID, TIOCGWINSZ, &ws) == 0)

        include/llvm/Config/*
        Makefile.config

TODO


# Install

    $ make VERBOSE=1 install 2>&1 | tee log_install

This takes up around 400 MiB, and needs roughly 1 min on kepler.SCHWINGE and 12
min on coulomb.SCHWINGE.


## Analysis

    $ toolchain/logs/process llvm install

TODO


# Testsuite

    $ make -k VERBOSE=1 LIT_ARGS='-v --threads=1' check-all 2>&1 | tee log_test_check-all
    $ make -k -C projects/test-suite/ 2>&1 | tee log_test_test-suite

`LIT_ARGS=-v` is default for `VERBOSE=1`, but we want only one worker thread,
for stable order and usable test output log.

This needs roughly 10 min (`check-all`) + 150 min (test-suite) = 160 min on
kepler.SCHWINGE and 45 min (`check-all`) + 165 min (test-suite) = 210 min on
coulomb.SCHWINGE.


## Analysis

    $ toolchain/logs/process llvm test

  * `LLVM :: CodeGen/X86/mult-alt-generic-i686.ll`

    This one, as well as a really large set of test from the test-suite fail on
    coulomb.SCHWINGE no matter whether a GNU/Hurd or GNU/Linux system is booted
    -- so all these are specific to the Athlon XP processor, hopefully.

  * `Clang :: Index/crash-recovery-modules.m`

    Also fails on GNU/Linux.  Tested `--enable-optimized
    --enable-expensive-checks --disable-threads --enable-debug-symbols
    --enable-debug-runtime`.  [[!LLVM_bug 11974]].

  * `Clang :: Misc/dev-fd-fs.c`

        $ cat < [...]/test/Misc/dev-fd-fs.c | Release+Debug+Asserts+Checks/bin/clang -x c /dev/fd/0 -E
        clang: error: no such file or directory: '/dev/fd/0'
        clang: error: no input files

    Compare to:

        $ cat < [...]/test/Misc/dev-fd-fs.c | gcc -x c /dev/fd/0 -E
        gcc: error: /dev/fd/0: (ipc/mig) bad request message ID
        gcc: warning: '-x c' after last input file has no effect
        gcc: fatal error: no input files
        compilation terminated.

    These work:

        $ Release+Debug+Asserts+Checks/bin/clang -x c /dev/fd/0 -E < [...]/test/Misc/dev-fd-fs.c
        [...]
        int x;
        $ gcc -x c /dev/fd/0 -E < [...]/test/Misc/dev-fd-fs.c
        [...]
        int x;

        #include <stdio.h>
        #include <unistd.h>
        
        int main(int argc, char *argv[])
        {   
          while (argc > 0)
            {
              int err;
              char *f = argv[argc -1];
        
              err = access(f, F_OK);
              if (err < 0)
                printf("%s: %m\n", f);
        
              argc--;
            }
        
          return 0;
        }

        $ ./a.out /dev/fd/0 < /dev/null
        $ cat < /dev/null | ./a.out /dev/fd/0
        /dev/fd/0: (ipc/mig) bad request message ID

    `file_check_access` fails with `MIG_BAD_ID`, meaning this RPC is not
    implemented.

    The difference is that the former directly refers to the `/dev/null`
    instance, whereas the latter goes through an intermediate pflocal instance.

    Similarly:

        $ stat /dev/fd/0 < /dev/null
          File: `/dev/fd/0'
          Size: 0               Blocks: 0          IO Block: 1048576 character special file
        Device: 17h/23d Inode: 342820      Links: 1     Device type: 0,0
        Access: (0666/crw-rw-rw-)  Uid: (    0/    root)   Gid: (    0/    root)
        Access: 2012-11-27 16:03:19.000000000 +0100
        Modify: 2012-11-27 16:03:19.000000000 +0100
        Change: 2012-11-27 16:03:19.000000000 +0100
         Birth: -
        $ cat < /dev/null | stat /dev/fd/0
          File: `/dev/fd/0'
          Size: 0               Blocks: 0          IO Block: 65536  fifo
        Device: 9h/9d   Inode: 0           Links: 0
        Access: (0000/p---------)  Uid: (    0/    root)   Gid: (    0/    root)
        Access: 1970-01-01 01:00:00.000000000 +0100
        Modify: 1970-01-01 01:00:00.000000000 +0100
        Change: 1970-01-01 01:00:00.000000000 +0100
         Birth: -

    `io_stat_request` fills in these values.    

  * `Clang :: Tooling/clang-check-builtin-headers.cpp`

    Fails: `fatal error: 'stddef.h' file not found`; succeeds when ran
    manually.

  * With `--enable-optimized --enable-expensive-checks --disable-threads
    --enable-debug-symbols --enable-debug-runtime`, there are a few new FAILs
    for both GNU/Linux and GNU/Hurd:

      * `Clang :: Tooling/auto-detect-from-source-parent-of-cwd.cpp`

      * `Clang :: Tooling/auto-detect-from-source-parent.cpp`

      * `Clang :: Tooling/clang-check-autodetect-dir.cpp`

    For all three, the `clang-check` invocation fails.  [[!LLVM_bug 15194]].

  * Several tests are not considered on GNU/Hurd.

        -PASS: Clang-Unit :: ASTMatchers/[...]/tschwinge/Horace_Silver.build/tools/clang/unittests/ASTMatchers/Release+Asserts/ASTMatchersTests/HasNameDeathTest.DiesOnEmptyName
        -PASS: Clang-Unit :: ASTMatchers/[...]/tschwinge/Horace_Silver.build/tools/clang/unittests/ASTMatchers/Release+Asserts/ASTMatchersTests/HasNameDeathTest.DiesOnEmptyPattern
        -PASS: Clang-Unit :: ASTMatchers/[...]/tschwinge/Horace_Silver.build/tools/clang/unittests/ASTMatchers/Release+Asserts/ASTMatchersTests/IsDerivedFromDeathTest.DiesOnEmptyBaseName
        -PASS: LLVM-Unit :: ADT/[...]/tschwinge/Horace_Silver.build/unittests/ADT/Release+Asserts/ADTTests/APFloatTest.SemanticsDeath
        -PASS: LLVM-Unit :: ADT/[...]/tschwinge/Horace_Silver.build/unittests/ADT/Release+Asserts/ADTTests/APFloatTest.StringDecimalDeath
        -PASS: LLVM-Unit :: ADT/[...]/tschwinge/Horace_Silver.build/unittests/ADT/Release+Asserts/ADTTests/APFloatTest.StringDecimalExponentDeath
        -PASS: LLVM-Unit :: ADT/[...]/tschwinge/Horace_Silver.build/unittests/ADT/Release+Asserts/ADTTests/APFloatTest.StringDecimalSignificandDeath
        -PASS: LLVM-Unit :: ADT/[...]/tschwinge/Horace_Silver.build/unittests/ADT/Release+Asserts/ADTTests/APFloatTest.StringHexadecimalDeath
        -PASS: LLVM-Unit :: ADT/[...]/tschwinge/Horace_Silver.build/unittests/ADT/Release+Asserts/ADTTests/APFloatTest.StringHexadecimalExponentDeath
        -PASS: LLVM-Unit :: ADT/[...]/tschwinge/Horace_Silver.build/unittests/ADT/Release+Asserts/ADTTests/APFloatTest.StringHexadecimalSignificandDeath
        -PASS: LLVM-Unit :: ADT/[...]/tschwinge/Horace_Silver.build/unittests/ADT/Release+Asserts/ADTTests/APIntTest.StringDeath
        -PASS: LLVM-Unit :: Support/[...]/tschwinge/Horace_Silver.build/unittests/Support/Release+Asserts/SupportTests/LeakDetector.Death1
        -PASS: LLVM-Unit :: Support/[...]/tschwinge/Horace_Silver.build/unittests/Support/Release+Asserts/SupportTests/ValueHandle.AssertingVH_Asserts

        GTEST_HAS_DEATH_TEST utils/unittest/googletest/include/gtest/internal/gtest-port.h

        -PASS: LLVM-Unit :: ADT/[...]/tschwinge/Horace_Silver.build/unittests/ADT/Release+Asserts/ADTTests/PackedVectorTest.SignedValues
        -PASS: LLVM-Unit :: ADT/[...]/tschwinge/Horace_Silver.build/unittests/ADT/Release+Asserts/ADTTests/PackedVectorTest.UnsignedValues

        EXPECT_DEBUG_DEATH utils/unittest/googletest/include/gtest/gtest-death-test.h

  * Differences in test-suite, that are not evidently floating-point issues,
    GNU/Linux vs. GNU/Hurd on coulomb.SCHWINGE:

         gcc-4.6 -I/media/erich/home/thomas/tmp/llvm/tschwinge/Horace_Silver.build/projects/test-suite/SingleSource/UnitTests -I/media/erich/home/thomas/tmp/llvm/test-suite/tschwinge/Art_Blakey/SingleSource/UnitTests -I/home/thomas/tmp/llvm/tschwinge/Horace_Silver.build/projects/test-suite/../../../Horace_Silver/projects/test-suite/include -I../../include -I/home/thomas/tmp/llvm/tschwinge/Horace_Silver.build/include -I/home/thomas/tmp/llvm/tschwinge/Horace_Silver/include -D_GNU_SOURCE -D__STDC_LIMIT_MACROS -DNDEBUG  -O3  /media/erich/home/thomas/tmp/llvm/test-suite/tschwinge/Art_Blakey/SingleSource/UnitTests/2007-04-25-weak.c -lm -o Output/2007-04-25-weak.native  -lstdc++ 
        +/media/erich/home/thomas/tmp/llvm/test-suite/tschwinge/Art_Blakey/SingleSource/UnitTests/2007-04-25-weak.c:3:1: warning: 'weak_import' attribute directive ignored [-Wattributes]
        +/tmp/ccWGwKvo.o: In function `main':
        +2007-04-25-weak.c:(.text.startup+0x7): undefined reference to `test_weak'
        +collect2: ld returned 1 exit status
        +make[2]: [Output/2007-04-25-weak.native] Error 1 (ignored)

    On GNU/Linux, the clamav tests are compiled with `-DC_LINUX`.

        +/media/erich/home/thomas/tmp/llvm/test-suite/tschwinge/Art_Blakey/MultiSource/Applications/lambda-0.1.3/lambda.cc:63:12: error: use of undeclared identifier 'MAXPATHLEN'
        +                char buf[MAXPATHLEN+1];

    ..., with follow-up failures.

    `projects/test-suite/MultiSource/Applications/obsequi` is not at all
    considered for GNU/Hurd.

        +/media/erich/home/thomas/tmp/llvm/test-suite/tschwinge/Art_Blakey/MultiSource/Benchmarks/Olden/voronoi/newvor.c:178:25: warning: implicit declaration of function 'memalign' is invalid in C99 [-Wimplicit-function-declaration]
        +    char* base = (char*)memalign(align_size, alloc_size);
        +                        ^
        +1 warning generated.

        +/media/erich/home/thomas/tmp/llvm/test-suite/tschwinge/Art_Blakey/MultiSource/Benchmarks/Prolangs-C/archie-client/get_vdir.c:213:20: error: use of undeclared identifier 'MAXPATHLEN'
        +                    char        l_name[MAX_DIR_LINESIZE];
        +                                       ^
        +/media/erich/home/thomas/tmp/llvm/test-suite/tschwinge/Art_Blakey/MultiSource/Benchmarks/Prolangs-C/archie-client/pprot.h:39:37: note: expanded from macro 'MAX_DIR_LINESIZE'
        +#define        MAX_DIR_LINESIZE 160+MAXPATHLEN /* Max linesize in directory */
        +                                    ^

    ..., and several more.