bug#57116: cling: missing some system header files

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hello,

Liliana Marie Prikler <liliana.prikler@ist.tugraz.at> writes:

> Am Dienstag, dem 09.08.2022 um 15:32 -0700 schrieb Gang Liang:
>> I had a fresh installation of cling from guix, and got the following
>> error. Seems some system headers are missing.
> You probably need gcc-toolchain installed alongside cling.

Indeed:

$ guix shell --pure cling -- cling '#include <iostream>'
In file included from input_line_3:1:
In file included from /gnu/store/069aq2v993kpc41yabp5b6vm4wb9jkhg-gcc-10.3.0/include/c++/iostream:39:
In file included from /gnu/store/069aq2v993kpc41yabp5b6vm4wb9jkhg-gcc-10.3.0/include/c++/ostream:38:
In file included from /gnu/store/069aq2v993kpc41yabp5b6vm4wb9jkhg-gcc-10.3.0/include/c++/ios:42:
In file included from /gnu/store/069aq2v993kpc41yabp5b6vm4wb9jkhg-gcc-10.3.0/include/c++/bits/ios_base.h:41:
In file included from /gnu/store/069aq2v993kpc41yabp5b6vm4wb9jkhg-gcc-10.3.0/include/c++/bits/locale_classes.h:40:
In file included from /gnu/store/069aq2v993kpc41yabp5b6vm4wb9jkhg-gcc-10.3.0/include/c++/string:55:
In file included from /gnu/store/069aq2v993kpc41yabp5b6vm4wb9jkhg-gcc-10.3.0/include/c++/bits/basic_string.h:6545:
In file included from /gnu/store/069aq2v993kpc41yabp5b6vm4wb9jkhg-gcc-10.3.0/include/c++/ext/string_conversions.h:44:
In file included from /gnu/store/069aq2v993kpc41yabp5b6vm4wb9jkhg-gcc-10.3.0/include/c++/cerrno:42:
In file included from /gnu/store/5h2w4qi9hk1qzzgi1w83220ydslinr4s-glibc-2.33/include/errno.h:28:
/gnu/store/5h2w4qi9hk1qzzgi1w83220ydslinr4s-glibc-2.33/include/bits/errno.h:26:11: fatal error: 'linux/errno.h' file not found
# include <linux/errno.h>
          ^~~~~~~~~~~~~~~

But:

$ guix shell --pure cling gcc-toolchain -- cling '#include <iostream>'

runs fine.

I tried this:

--8<---------------cut here---------------start------------->8---
modified   gnu/packages/llvm.scm
@@ -79,6 +79,12 @@ (define-module (gnu packages llvm)
   #:export (make-lld-wrapper
             system->llvm-target))
 
+;;; Lazily resolve to avoid top-level cycles between modules.
+(define gcc-toolchain*
+  (delay (module-ref (resolve-interface '(gnu packages commencement))
+                     'gcc-toolchain)))
+
+
 (define* (system->llvm-target #:optional
                               (system (or (and=> (%current-target-system)
                                                  gnu-triplet->nix-system)
@@ -2215,11 +2221,25 @@ (define-public cling
             (add-after 'install 'delete-static-libraries
               ;; This reduces the size from 17 MiB to 5.4 MiB.
               (lambda _
-                (for-each delete-file (find-files #$output "\\.a$")))))))
+                (for-each delete-file (find-files #$output "\\.a$"))))
+            (add-after 'install 'wrap-cling
+              ;; Wrap the 'cling' command so that it can locate the GCC
+              ;; toolchain provided headers.  Use 'suffix so as to allow users
+              ;; to override which headers are used.
+              (lambda* (#:key outputs #:allow-other-keys)
+                (define gcc-toolchain #$(this-package-input "gcc-toolchain"))
+                (wrap-program (search-input-file outputs "bin/cling")
+                  `("C_INCLUDE_PATH" suffix
+                    (,(string-append gcc-toolchain "/include")))
+                  `("CPLUS_INCLUDE_PATH" suffix
+                    (,(string-append gcc-toolchain "/include/c++")
+                     ,(string-append gcc-toolchain "/include")))
+                  `("LIBRARY_PATH" suffix
+                    (,(string-append gcc-toolchain "/lib")))))))))
       (native-inputs
        (list python python-lit))
       (inputs
-       (list clang-cling llvm-cling))
+       (list clang-cling (force gcc-toolchain*) llvm-cling))
       (home-page "https://root.cern/cling/")
       (synopsis "Interactive C++ interpreter")
       (description "Cling is an interactive C++17 standard compliant
--8<---------------cut here---------------end--------------->8---

but it gave:

--8<---------------cut here---------------start------------->8---
/gnu/store/lpwfmh4v2w2qbpdmmva0si32c9havn95-llvm-cling-9.0.1/lib/libLLVM-9.so(_ZN4llvm3sys15PrintStackTraceERNS_11raw_ostreamE+0x1a)[0x7f76e20ea81a]
/gnu/store/lpwfmh4v2w2qbpdmmva0si32c9havn95-llvm-cling-9.0.1/lib/libLLVM-9.so(_ZN4llvm3sys17RunSignalHandlersEv+0x34)[0x7f76e20e8894]
/gnu/store/lpwfmh4v2w2qbpdmmva0si32c9havn95-llvm-cling-9.0.1/lib/libLLVM-9.so(+0x7129c2)[0x7f76e20e89c2]
/gnu/store/5h2w4qi9hk1qzzgi1w83220ydslinr4s-glibc-2.33/lib/libpthread.so.0(+0x11d80)[0x7f76e6c3fd80]
/gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/libstdc++.so.6(_ZTVN10__cxxabiv120__si_class_type_infoE+0x10)[0x7f76e19c0c78]
Stack dump:
0.      Program arguments: /gnu/store/x48h88ckmkk5vh9g36d2cnmhw23x9ql5-profile/bin/cling #include <iostream>
--8<---------------cut here---------------end--------------->8---

I'm not sure why.

Should we close it as 'notabug', or persist with the attempt to wrap the
cling binary with the include paths required to ease its setup?

Thanks,

Maxim