gambit/gambit

Gambit is an efficient implementation of the Scheme programming language.

Ricardo G. Herdt

@r.herdt_gitlab

Hi there!
While porting my json-rpc to Gambit, I found a possible bug:

> (alist->hash-table '())
*** ERROR IN (stdin)@2.1 -- PAIR LIST expected
(srfi/69#alist->hash-table '())

Trying to convert an empty list into a hash-table sounds lame, but I'm using it as a set-filter for make-parameter, like this:

(define json-rpc-handler-table
  (make-parameter '() (lambda (alist) (alist->hash-table alist equal?))))

I'm using v4.9.4. BTW, I also noticed that gsi still shows v4.9.3

Ricardo G. Herdt

@r.herdt_gitlab

another bug: define-values seems not to work inside a lambda/function definition. According to R7RS define-values "is allowed wherever define is allowed":

> (define (f) (define-values (a b) 1 2) #t)     
*** ERROR IN (stdin)@2.13 -- Unknown expression parsing exception

Marc Feeley

@feeley

The bug with SRFI 69 is kind of embarassing… now fixed and I have added unit tests for this.
Concerning the problem with define-values, the correct implementation of this form and other R7RS forms depends on the new macro system we are working on… in the meantime you can use this definition:

(define-macro (define-values vars expr)
  (cond ((null? vars)
         (let ((temp (gensym)))
           `(##define ,temp
              (##call-with-values (##lambda () ,expr) ##list))))
        ((null? (cdr vars))
         `(##define ,(car vars) ,expr))
        (else
         (let ((temp (gensym)))
           `(##begin
              (##define ,temp
                (##call-with-values (##lambda () ,expr) ##list))
              ,@(map (lambda (var)
                       `(##define ,var
                          (##if (##pair? ,temp)
                                (##let ((val (##car ,temp)))
                                  (##set! ,temp (##cdr ,temp))
                                  val)
                                (##error "too few values"))))
                     vars))))))

Ricardo G. Herdt

@r.herdt_gitlab

Thanks Marc!

Mark Friedman

@mark-friedman

In the "try" IDE, I'd like to change the orientation of the console and editor panes from horizontal to vertical, i.e. have the console on top of the editor. I thought that maybe just changing UI.js:59 from:

  elem.classList.add('g-h-panes');

  elem.classList.add('g-v-panes');

might suffice, but no such luck. I end up just seeing the console. Most all of the class/style stuff seems to be nicely abstracted but I'm guessing that there is an assumption built somewhere in there (maybe the CSS) that is breaking it. Any guidance would be appreciated. My CSS-fu is not strong.

Thanks.

Mark Friedman

@mark-friedman

Another question about the web-based IDE in contrib/try: Do I really need to server all the files in the try\try\lib directory? I assume that some or all of it is to support a set of auto-loaded modules, some or all of which are needed by the demo code. Are any of them needed for core R7RS-small execution? Also, are all the various file types in a given subdirectory necessary? Typically I will see foo.scm, foo.js, foo#.scm, foo.o1, foo.o1.js, and foo.o1.js.gzfiles.

I'm fairly new to Gambit (though not to Scheme), so forgive my naiveté ;-)

Marc Feeley

@feeley

@mark-friedman Sorry but my CSS-fu is not that strong either. As I recall, CodeMirror causes a lot of headaches to do resizing correctly. I did notice however that the pane-splitter is actually dragable close to the top of the REPL and you can drag it down to reveal the console. I hope someone with a PhD in CSS can sort out this issue...

1 reply

tck42

@tck42

Is there any way to override the default CFLAGS etc that gsc issues at runtime during build without changing the flags that are used to compile? The bleeding edge Fedora build is using custom linker scripts that are fine for gambit itself but they reference a linker script that's only available on the build server. I'd like to open the bug with a suggested working build. I checked the build docs but it's not clear to me which options end up where.

Mark Friedman

@mark-friedman

Thanks, @feeley for your answer about the orientation of the console and editor panes in "try". Do you (or anybody else) have an answer for my subsequent "try"-related question relating to all the different files and files types?

Konstantin Astafurov

@konstantin-aa

Hello, I'm writing some scheme that involves parsing JSON, and am having a bit of trouble with using the json.scm from here

https://github.com/gambit/gambit/blob/master/contrib/GambitREPL/json.scm

Marc Feeley

@feeley

@mark-friedman None of the try/lib files are essential… they are there for dynamic loading of various standard modules… if you use the R7RS define-library then you will need try/lib/_define-library

8 replies

@konstantin-aa What troubles are you having?

Konstantin Astafurov

@konstantin-aa

I keep getting seg faults, which files should I be compiling?

Marc Feeley

@feeley

@tck42 You can set GAMBUILD_VERBOSE=yes or use gsc -verbose … to get a trace of the C compiler invocations. For example:

$ GAMBUILD_VERBOSE=yes gsc foo.scm
gcc-9  -O1    -bundle  -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -foptimize-sibling-calls -fomit-frame-pointer -fPIC -fno-common -mpc64    -D___SINGLE_HOST -D___DYNAMIC -I"/usr/local/Gambit/include" -o 'foo.o1'   'foo.c'
$ GAMBUILD_VERBOSE=yes gsc -exe foo.scm
gcc-9  -O1    -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -foptimize-sibling-calls -fomit-frame-pointer -fPIC -fno-common -mpc64   -D___SINGLE_HOST  -I"/usr/local/Gambit/include" -c -o 'foo.o'  'foo.c'
gcc-9  -O1    -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -foptimize-sibling-calls -fomit-frame-pointer -fPIC -fno-common -mpc64   -D___SINGLE_HOST  -I"/usr/local/Gambit/include" -c -o 'foo_.o'  'foo_.c'
gcc-9     -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -foptimize-sibling-calls -fomit-frame-pointer -fPIC -fno-common -mpc64    -D___SINGLE_HOST  -I"/usr/local/Gambit/include"  -o 'foo'   'foo_.o' 'foo.o' "/usr/local/Gambit/lib/libgambit.a”

After gsc has generated the C file(s) it will call the ~~bin/gambuild-Cscript as the last step of the compilation to invoke the C compiler and linker. When that script is called with no command line arguments it will dump all of the environment variable bindings it uses:

$ `gsc -e '(display (path-expand "~~bin/gambuild-C"))'`
C_COMPILER="gcc-9"
C_PREPROC="gcc-9 -E"
PKG_CONFIG="pkg-config"
FLAGS_OBJ=" -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -foptimize-sibling-calls -fomit-frame-pointer -fPIC -fno-common -mpc64 "
FLAGS_DYN=" -bundle -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -foptimize-sibling-calls -fomit-frame-pointer -fPIC -fno-common -mpc64 "
FLAGS_LIB=" -dynamiclib -install_name \$(libdir)/\$(LIBRARY)\$(LIB_VERSION_SUFFIX) "
FLAGS_EXE=" -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -foptimize-sibling-calls -fomit-frame-pointer -fPIC -fno-common -mpc64 "
FLAGS_OPT=" -O1"
FLAGS_OPT_RTS=" -O3"
DEFS_OBJ=" -D___SINGLE_HOST "
DEFS_DYN=" -D___SINGLE_HOST -D___DYNAMIC"
DEFS_LIB=" -D___SINGLE_HOST "
DEFS_EXE=" -D___SINGLE_HOST “
…

You can see for example that FLAGS_DYN are the flags used for compiling a dynamically loadable object file.
If you need additional command line parameters to be passed to the C compiler you can do it manually with the -cc-options XXX argument to gsc, or set CFLAGS.

tck42

@tck42

@feeley Thanks very much for this info!

Bradley Lucier

@gambiteer

There's also:

    -ld-options 'option ...'    Extra command line options for C linker
    -ld-options-prelude 'option ...'

from gsc --help.

Marc Feeley

@feeley

@konstantin-aa Here’s how you can compile the module, import it and call it:

$ cp contrib/GambitREPL/json*.scm .
$ gsc . json
$ gsi .
Gambit v4.9.4-39-g9a887b80

> (import json)
> (define x (call-with-input-string "{\"name\":\"John\", \"age\":30, \"car\":null}" json-read))
> (table-ref x "age")
30
> (table->list x)
(("name" . "John") ("car") ("age" . 30))

tck42

@tck42

@gambiteer thanks as well! I think it'll come down to simply removing the problematic flags via sed on gambuild-C before the rpm gets created.

Marc Feeley

@feeley

@tck42 Let me know what flag is a problem and if it is a serious problem I can add an option to the configure script to disable that flag.

Konstantin Astafurov

@konstantin-aa

thank you!

tck42

@tck42

@feeley This isn't actually with gambit per se; when building gambit from source for fedora, the fedora build process is adding (among a large # of other flags) a CFLAG telling the linker to use a custom script that adds a so-called "package note" to the output binaries that can be used for bug reports. That linker script is available at time of building gambit (it's generated as part of the build process), but when using gambit on a system that it wasn't built on, that linker script doesn't exist. So it's more about how gambit is generating the contents of gambuild-C I think. It's easy enough to remove inappropriate flags directly from the file as part of the package spec. Though I may be misunderstanding; I was also going to try to rebuilt Gambit with FLAGS_* explicitly set to see if it would take those instead of taking the various flags that were used to compile gambit.

I see a bunch of .in files that appear to be the source to that file, was going to have a look there and see if there's any way I can change how the package is being built to get the flags out of gambuild-C without any changes to gambit

Marc Feeley

@feeley

@tck42 I don’t think the configure script copies the current setting of CFLAGS into the makefiles and the gambuild-C script. So when a Scheme file is compiled by gsc it should only be using (implicitly) the setting of CFLAGS at that moment, i.e. there is no relationship with the build environment.

tck42

@tck42

On the 4.9.3 system I first noticed this on, those flags are indeed hardcoded into gambcomp-C (these are the packages supplied by Fedora); overriding with for instance "CFLAGS= gsc test.scm" also had no effect, though if I remove the single flag directly from gambcomp-C it did fix the issue. I'm guessing I can also override via gsc switch, but my goal is to get the package creating a gsc and gambuild-C that uses the flags as close to the rpm build system's set of flags (some hardening flags) but also removing anything that won't properly work on the build system itself (ie this flag that is referencing a linker script that does not get packaged into the rpm).

Same for the 4.9.4 I built myself - it seems to be setting those in the file from some combination of the CFLAGS, LDFLAGS and CPPFLAGS that are around when configure gets run (I think).

Bradley Lucier

@gambiteer

@tck42 I'm curious, what flag is it?

tck42

@tck42

let me get to the system where I'm using the fedora package, give me 2 seconds

-Wl,-dT,/builddir/build/BUILD/.package_note-gambit-c-4.9.3-7.fc36.x86_64.ld

that file exists on the system that created the package, but does not (and I believe should not) get installed with the package on an end user fedora system

even if it was, it wouldn't be appropriate to use that linker file for binaries output by gsc - if gsc was used to generate another package, that file should be generated for that package, and the argument should be added to the flags in that package's spec (I think)

Marc Feeley

@feeley

can you confirm that the script bin/gambuild-C contains that flag? and where...

tck42

@tck42

yep - so on the fedora system (it's 4.9.3 at thsi time, when I file this bug to them I'll suggest they update to 4.9.4 as well) if I look at /usr/lib64/gambit-c/bin/gambcomp-C I see that FLAGS_DYN, _LIB, and _EXE all have that package_note argument.

Marc Feeley

@feeley

and did you try with v4.9.4?

tck42

@tck42

Yep - same exact behavior, though the file name has changed from gambcomp-C to gambuild-C

Marc Feeley

@feeley

can you show the lines here?

tck42

@tck42

FLAGS_DYN="-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -Wl,--build-id=sha1 -Wl,-dT,/builddir/build/BUILD/.package_note-gambit-c-4.9.3-7.fc36.x86_64.ld -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64  -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection   -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -fmodulo-sched -freschedule-modulo-scheduled-loops -fomit-frame-pointer -fPIC -fno-common -mpc64   -rdynamic -shared"
FLAGS_LIB="-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -Wl,--build-id=sha1 -Wl,-dT,/builddir/build/BUILD/.package_note-gambit-c-4.9.3-7.fc36.x86_64.ld -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64  -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection    -rdynamic -shared"
FLAGS_EXE="-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -Wl,--build-id=sha1 -Wl,-dT,/builddir/build/BUILD/.package_note-gambit-c-4.9.3-7.fc36.x86_64.ld -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64  -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection   -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -fmodulo-sched -freschedule-modulo-scheduled-loops -fomit-frame-pointer -fPIC -fno-common -mpc64   -rdynamic"

Sorry - the above was 4.93, below is 4.9.4 (I think they're identical

FLAGS_DYN="-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -Wl,--build-id=sha1 -Wl,-dT,/home/tck42/rpmbuild/BUILD/gambit-4.9.4/.package_note-gambit-c-4.9.4-1.fc37.x86_64.ld -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64  -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection   -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -foptimize-sibling-calls -fmodulo-sched -freschedule-modulo-scheduled-loops -fomit-frame-pointer -fPIC -fno-common -mpc64   -rdynamic -shared"
FLAGS_LIB="-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -Wl,--build-id=sha1 -Wl,-dT,/home/tck42/rpmbuild/BUILD/gambit-4.9.4/.package_note-gambit-c-4.9.4-1.fc37.x86_64.ld -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64  -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection    -rdynamic -shared"
FLAGS_EXE="-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -Wl,--build-id=sha1 -Wl,-dT,/home/tck42/rpmbuild/BUILD/gambit-4.9.4/.package_note-gambit-c-4.9.4-1.fc37.x86_64.ld -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64  -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection   -Wno-unused -Wno-write-strings -Wdisabled-optimization -fwrapv -fno-strict-aliasing -fno-trapping-math -fno-math-errno -fschedule-insns2 -foptimize-sibling-calls -fmodulo-sched -freschedule-modulo-scheduled-loops -fomit-frame-pointer -fPIC -fno-common -mpc64   -rdynamic"

Marc Feeley

@feeley

I see the problem in configure.ac:

if test "$ENABLE_CPLUSPLUS" = yes; then
  CORCXXFLAGS="$CXXFLAGS"
else
  CORCXXFLAGS="$CFLAGS"
fi

FLAGS_OBJ="$CORCXXFLAGS $FLAGS_OBJ $FLAGS_OBJ_DYN $FLAGS_OBJ_DYN_LIB_EXE"
FLAGS_DYN="$LDFLAGS $CORCXXFLAGS $FLAGS_DYN $FLAGS_OBJ_DYN $FLAGS_OBJ_DYN_LIB_EXE $FLAGS_DYN_LIB"

so I was wrong and CFLAGS from the build environment is being captured in the generated gambuild-C script...

tck42

@tck42

Right - BUT - isn't that appropriate, at least for the gambuild-C file that's used for building gambit itself?

Marc Feeley

@feeley

however, I think this is probably the correct behavior because you want (in general) the same C compiler flags to be used to guarantee that the generated machine code is compatible

tck42

@tck42

right - it's just about removing that one flag, which is why I'm thinking the easiest and I guess most correct way is just to patch / sed it out of the gambuild-C that actually gets installed. That linker flag can be dropped I think, since it's just tagging the output binaries with metadata that aren't even appropriate for end user build binaries

(I'll just be proposing this in the bug, the actual packager may have other ideas on how to fix it in the spec file)

Marc Feeley

@feeley

I don’t think a solution that contains the word “patch” can ever be viewed as the correct solution...

tck42

@tck42

Hmm, that's true (I'm used to arch where those kinds of patches are common in their build scripts); though the existing fedora spec is alread patching configure presumably to work properly with buildroot or whatever they're using for the actual install. I don't know that a general solution is possible without somehow generating gambuild-C twice; once before building, and once just before packaging

Marc Feeley

@feeley

probably the better option would be to add a configure flag to override CFLAGS… for example ./configure --enable-cflags=“…” that way in circumstances where the build CFLAGS contains some unwanted information then it can be removed

another option would be to remove the reference to CFLAGS in the configure script, and cross our fingers that on all systems the build machine and target machines have compatible settings for CFLAGS

tck42

@tck42

Hmm - I'm personally too ignorant on the topic but the second method sounds like it could cause problems (ie where we know we need a particular flag on a particular architecture). Splitting into "flags we use to build gsc" and "flags gsc will later use" and then defaulting the packaged gsc's flags to the build flags does sound like the way to go.

I'm happy to take a shot at a pull request, been meaning to learn and understand autoconf and friends

tck42

@tck42

for what it's worth, fedora's build system is actually adding that flag to LDFLAGS, not CFLAGS or CXXFLAGS, though I think basically all three of those would be useful to have a configure flag for the same behavior and probably similar to implement. Will submit a pull request when I have it working

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