rust: Do not link with libdl and libpthread unconditionally

  Hi everyone,

This patch checks for the presence of dlopen and pthread_create in libc. If that is not the
case, we check for the existence of -ldl and -lpthread, as these libraries are required to
link the Rust runtime to our Rust frontend.

If these libs are not present on the system, then we disable the Rust frontend.

This was tested on x86_64, in an environment with a recent GLIBC and in a container with GLIBC
2.27.

Apologies for sending it in so late.

ChangeLog:

	* Makefile.tpl: Add CRAB1_LIBS variable.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Check if -ldl and -lpthread are needed, and if so, add
	them to CRAB1_LIBS.

gcc/rust/ChangeLog:

	* Make-lang.in: Remove overazealous LIBS = -ldl -lpthread line, link
	crab1 against CRAB1_LIBS.
---
 Makefile.in           |   3 +
 Makefile.tpl          |   3 +
 configure             | 157 ++++++++++++++++++++++++++++++++++++++++++
 configure.ac          |  94 +++++++++++++++++++++++++
 gcc/rust/Make-lang.in |   2 +-
 5 files changed, 258 insertions(+), 1 deletion(-)
  

On Fri, Apr 19, 2024 at 11:49 AM Arthur Cohen <arthur.cohen@embecosm.com> wrote:
>
> Hi everyone,
>
> This patch checks for the presence of dlopen and pthread_create in libc. If that is not the
> case, we check for the existence of -ldl and -lpthread, as these libraries are required to
> link the Rust runtime to our Rust frontend.
>
> If these libs are not present on the system, then we disable the Rust frontend.
>
> This was tested on x86_64, in an environment with a recent GLIBC and in a container with GLIBC
> 2.27.
>
> Apologies for sending it in so late.

For example GCC_ENABLE_PLUGINS simply does

     # Check -ldl
     saved_LIBS="$LIBS"
     AC_SEARCH_LIBS([dlopen], [dl])
     if test x"$ac_cv_search_dlopen" = x"-ldl"; then
       pluginlibs="$pluginlibs -ldl"
     fi
     LIBS="$saved_LIBS"

which I guess would also work for pthread_create?  This would simplify
the code a bit.

> ChangeLog:
>
>         * Makefile.tpl: Add CRAB1_LIBS variable.
>         * Makefile.in: Regenerate.
>         * configure: Regenerate.
>         * configure.ac: Check if -ldl and -lpthread are needed, and if so, add
>         them to CRAB1_LIBS.
>
> gcc/rust/ChangeLog:
>
>         * Make-lang.in: Remove overazealous LIBS = -ldl -lpthread line, link
>         crab1 against CRAB1_LIBS.
> ---
>  Makefile.in           |   3 +
>  Makefile.tpl          |   3 +
>  configure             | 157 ++++++++++++++++++++++++++++++++++++++++++
>  configure.ac          |  94 +++++++++++++++++++++++++
>  gcc/rust/Make-lang.in |   2 +-
>  5 files changed, 258 insertions(+), 1 deletion(-)
>
> diff --git a/Makefile.in b/Makefile.in
> index db4fa6c6260..34c5550beca 100644
> --- a/Makefile.in
> +++ b/Makefile.in
> @@ -197,6 +197,7 @@ HOST_EXPORTS = \
>         $(BASE_EXPORTS) \
>         CC="$(CC)"; export CC; \
>         ADA_CFLAGS="$(ADA_CFLAGS)"; export ADA_CFLAGS; \
> +       CRAB1_LIBS="$(CRAB1_LIBS)"; export CRAB1_LIBS; \
>         CFLAGS="$(CFLAGS)"; export CFLAGS; \
>         CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
>         CXX="$(CXX)"; export CXX; \
> @@ -450,6 +451,8 @@ GOCFLAGS = $(CFLAGS)
>  GDCFLAGS = @GDCFLAGS@
>  GM2FLAGS = $(CFLAGS)
>
> +CRAB1_LIBS = @CRAB1_LIBS@
> +
>  PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
>
>  GUILE = guile
> diff --git a/Makefile.tpl b/Makefile.tpl
> index 1d5813cd569..8f4bf297918 100644
> --- a/Makefile.tpl
> +++ b/Makefile.tpl
> @@ -200,6 +200,7 @@ HOST_EXPORTS = \
>         $(BASE_EXPORTS) \
>         CC="$(CC)"; export CC; \
>         ADA_CFLAGS="$(ADA_CFLAGS)"; export ADA_CFLAGS; \
> +       CRAB1_LIBS="$(CRAB1_LIBS)"; export CRAB1_LIBS; \
>         CFLAGS="$(CFLAGS)"; export CFLAGS; \
>         CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
>         CXX="$(CXX)"; export CXX; \
> @@ -453,6 +454,8 @@ GOCFLAGS = $(CFLAGS)
>  GDCFLAGS = @GDCFLAGS@
>  GM2FLAGS = $(CFLAGS)
>
> +CRAB1_LIBS = @CRAB1_LIBS@
> +
>  PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
>
>  GUILE = guile
> diff --git a/configure b/configure
> index 3b0abeb8b2e..75b489a5f57 100755
> --- a/configure
> +++ b/configure
> @@ -690,6 +690,7 @@ extra_host_zlib_configure_flags
>  extra_host_libiberty_configure_flags
>  stage1_languages
>  host_libs_picflag
> +CRAB1_LIBS
>  PICFLAG
>  host_shared
>  gcc_host_pie
> @@ -8875,6 +8876,142 @@ fi
>
>
>
> +# Rust requires -ldl and -lpthread if you are using an old glibc that does not include them by
> +# default, so we check for them here
> +
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if libc includes libdl and libpthread" >&5
> +$as_echo_n "checking if libc includes libdl and libpthread... " >&6; }
> +
> +ac_ext=c
> +ac_cpp='$CPP $CPPFLAGS'
> +ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
> +ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
> +ac_compiler_gnu=$ac_cv_c_compiler_gnu
> +
> +
> +requires_ldl=no
> +requires_lpthread=no
> +missing_rust_dynlibs=none
> +
> +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> +/* end confdefs.h.  */
> +#include <dlfcn.h>
> +int
> +main ()
> +{
> +dlopen(0,0);
> +  ;
> +  return 0;
> +}
> +_ACEOF
> +if ac_fn_c_try_link "$LINENO"; then :
> +
> +else
> +  requires_ldl=yes
> +
> +fi
> +rm -f core conftest.err conftest.$ac_objext \
> +    conftest$ac_exeext conftest.$ac_ext
> +
> +if test $requires_ldl = yes; then
> +    tmp_LIBS=$LIBS
> +    LIBS="$LIBS -ldl"
> +
> +    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> +/* end confdefs.h.  */
> +#include <dlfcn.h>
> +int
> +main ()
> +{
> +dlopen(0,0);
> +  ;
> +  return 0;
> +}
> +_ACEOF
> +if ac_fn_c_try_link "$LINENO"; then :
> +  CRAB1_LIBS="$CRAB1_LIBS -ldl"
> +else
> +  missing_rust_dynlibs="libdl"
> +
> +fi
> +rm -f core conftest.err conftest.$ac_objext \
> +    conftest$ac_exeext conftest.$ac_ext
> +
> +    LIBS=$tmp_LIBS
> +fi
> +
> +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> +/* end confdefs.h.  */
> +#include <pthread.h>
> +int
> +main ()
> +{
> +pthread_create(NULL,NULL,NULL,NULL);
> +
> +  ;
> +  return 0;
> +}
> +_ACEOF
> +if ac_fn_c_try_link "$LINENO"; then :
> +
> +else
> +  requires_lpthread=yes
> +
> +fi
> +rm -f core conftest.err conftest.$ac_objext \
> +    conftest$ac_exeext conftest.$ac_ext
> +
> +if test $requires_lpthread = yes; then
> +    tmp_LIBS=$LIBS
> +    LIBS="$LIBS -lpthread"
> +
> +    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> +/* end confdefs.h.  */
> +#include <pthread.h>
> +int
> +main ()
> +{
> +pthread_create(NULL,NULL,NULL,NULL);
> +
> +  ;
> +  return 0;
> +}
> +_ACEOF
> +if ac_fn_c_try_link "$LINENO"; then :
> +  CRAB1_LIBS="$CRAB1_LIBS -lpthread"
> +else
> +  missing_rust_dynlibs="$missing_rust_dynlibs, libpthread"
> +
> +fi
> +rm -f core conftest.err conftest.$ac_objext \
> +    conftest$ac_exeext conftest.$ac_ext
> +
> +    LIBS=$tmp_LIBS
> +fi
> +
> +if test "$missing_rust_dynlibs" = "none"; then
> +  if test $requires_ldl = yes -a $requires_lpthread = yes; then
> +    { $as_echo "$as_me:${as_lineno-$LINENO}: result: not included, but available" >&5
> +$as_echo "not included, but available" >&6; }
> +  else
> +    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
> +$as_echo "yes" >&6; }
> +  fi
> +else
> +  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no: missing $missing_rust_dynlibs" >&5
> +$as_echo "no: missing $missing_rust_dynlibs" >&6; }
> +fi
> +
> +CRAB1_LIBS="$CRAB1_LIBS"
> +
> +
> +ac_ext=c
> +ac_cpp='$CPP $CPPFLAGS'
> +ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
> +ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
> +ac_compiler_gnu=$ac_cv_c_compiler_gnu
> +
> +
>  # If we are building PIC/PIE host executables, and we are building dependent
>  # libs (e.g. GMP) in-tree those libs need to be configured to generate PIC
>  # code.
> @@ -9115,6 +9252,26 @@ $as_echo "$as_me: WARNING: GDC is required to build $language" >&2;}
>              ;;
>          esac
>
> +        # Disable Rust if we are missing some required C libraries for the Rust runtime.
> +        case ${add_this_lang}:${language}:${missing_rust_dynlibs} in
> +          *:rust:none)
> +            # Nothing to do - we're not missing any C libraries
> +            ;;
> +          yes:rust:*)
> +            as_fn_error $? "some C libraries are required to build $language: $missing_rust_dynlibs" "$LINENO" 5
> +            add_this_lang=unsupported
> +            ;;
> +          all:rust:*)
> +            { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: some C libraries are required to build $language: $missing_rust_dynlibs" >&5
> +$as_echo "$as_me: WARNING: some C libraries are required to build $language: $missing_rust_dynlibs" >&2;}
> +            add_this_lang=unsupported
> +            ;;
> +          *:rust:*)
> +            # Silently disable.
> +            add_this_lang=unsupported
> +            ;;
> +        esac
> +
>          # Disable jit if -enable-host-shared not specified
>          # but not if building for Mingw. All code in Windows
>          # is position independent code (PIC).
> diff --git a/configure.ac b/configure.ac
> index 042681c27be..d96b7b5432e 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -2037,6 +2037,81 @@ fi
>
>  AC_SUBST(PICFLAG)
>
> +# Rust requires -ldl and -lpthread if you are using an old glibc that does not include them by
> +# default, so we check for them here
> +
> +AC_MSG_CHECKING([if libc includes libdl and libpthread])
> +
> +AC_LANG_PUSH([C])
> +
> +requires_ldl=no
> +requires_lpthread=no
> +missing_rust_dynlibs=none
> +
> +AC_LINK_IFELSE(
> +  [AC_LANG_PROGRAM(
> +    [#include <dlfcn.h>],
> +    [dlopen(0,0);],
> +  )],
> +  [],
> +  [requires_ldl=yes]
> +)
> +
> +if test $requires_ldl = yes; then
> +    tmp_LIBS=$LIBS
> +    LIBS="$LIBS -ldl"
> +
> +    AC_LINK_IFELSE(
> +      [AC_LANG_PROGRAM(
> +        [#include <dlfcn.h>],
> +        [dlopen(0,0);],
> +      )],
> +      [CRAB1_LIBS="$CRAB1_LIBS -ldl"],
> +      [missing_rust_dynlibs="libdl"]
> +    )
> +
> +    LIBS=$tmp_LIBS
> +fi
> +
> +AC_LINK_IFELSE(
> +  [AC_LANG_PROGRAM(
> +    [#include <pthread.h>],
> +    [pthread_create(NULL,NULL,NULL,NULL);]
> +  )],
> +  [],
> +  [requires_lpthread=yes]
> +)
> +
> +if test $requires_lpthread = yes; then
> +    tmp_LIBS=$LIBS
> +    LIBS="$LIBS -lpthread"
> +
> +    AC_LINK_IFELSE(
> +      [AC_LANG_PROGRAM(
> +        [#include <pthread.h>],
> +        [pthread_create(NULL,NULL,NULL,NULL);]
> +      )],
> +      [CRAB1_LIBS="$CRAB1_LIBS -lpthread"],
> +      [missing_rust_dynlibs="$missing_rust_dynlibs, libpthread"]
> +    )
> +
> +    LIBS=$tmp_LIBS
> +fi
> +
> +if test "$missing_rust_dynlibs" = "none"; then
> +  if test $requires_ldl = yes -a $requires_lpthread = yes; then
> +    AC_MSG_RESULT([not included, but available])
> +  else
> +    AC_MSG_RESULT([yes])
> +  fi
> +else
> +  AC_MSG_RESULT([no: missing $missing_rust_dynlibs])
> +fi
> +
> +AC_SUBST(CRAB1_LIBS, "$CRAB1_LIBS")
> +
> +AC_LANG_POP([C])
> +
>  # If we are building PIC/PIE host executables, and we are building dependent
>  # libs (e.g. GMP) in-tree those libs need to be configured to generate PIC
>  # code.
> @@ -2274,6 +2349,25 @@ if test -d ${srcdir}/gcc; then
>              ;;
>          esac
>
> +        # Disable Rust if we are missing some required C libraries for the Rust runtime.
> +        case ${add_this_lang}:${language}:${missing_rust_dynlibs} in
> +          *:rust:none)
> +            # Nothing to do - we're not missing any C libraries
> +            ;;
> +          yes:rust:*)
> +            AC_MSG_ERROR([some C libraries are required to build $language: $missing_rust_dynlibs])
> +            add_this_lang=unsupported
> +            ;;
> +          all:rust:*)
> +            AC_MSG_WARN([some C libraries are required to build $language: $missing_rust_dynlibs])
> +            add_this_lang=unsupported
> +            ;;
> +          *:rust:*)
> +            # Silently disable.
> +            add_this_lang=unsupported
> +            ;;
> +        esac
> +
>          # Disable jit if -enable-host-shared not specified
>          # but not if building for Mingw. All code in Windows
>          # is position independent code (PIC).
> diff --git a/gcc/rust/Make-lang.in b/gcc/rust/Make-lang.in
> index 8db04163618..bb2e246f9fa 100644
> --- a/gcc/rust/Make-lang.in
> +++ b/gcc/rust/Make-lang.in
> @@ -214,7 +214,7 @@ LIBPROC_MACRO_INTERNAL = ../libgrust/libproc_macro_internal/libproc_macro_intern
>  crab1$(exeext): $(RUST_ALL_OBJS) attribs.o $(BACKEND) $(LIBDEPS) $(LIBPROC_MACRO_INTERNAL) $(rust.prev)
>         @$(call LINK_PROGRESS,$(INDEX.rust),start)
>         +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
> -             $(RUST_ALL_OBJS) attribs.o $(BACKEND) $(LIBS) $(LIBPROC_MACRO_INTERNAL) $(BACKENDLIBS)
> +             $(RUST_ALL_OBJS) attribs.o $(BACKEND) $(LIBS) $(CRAB1_LIBS) $(LIBPROC_MACRO_INTERNAL) $(BACKENDLIBS)
>         @$(call LINK_PROGRESS,$(INDEX.rust),end)
>
>  # Build hooks.
> --
> 2.42.1
>
  

Hi Richard,

On 4/30/24 09:55, Richard Biener wrote:
> On Fri, Apr 19, 2024 at 11:49 AM Arthur Cohen <arthur.cohen@embecosm.com> wrote:
>>
>> Hi everyone,
>>
>> This patch checks for the presence of dlopen and pthread_create in libc. If that is not the
>> case, we check for the existence of -ldl and -lpthread, as these libraries are required to
>> link the Rust runtime to our Rust frontend.
>>
>> If these libs are not present on the system, then we disable the Rust frontend.
>>
>> This was tested on x86_64, in an environment with a recent GLIBC and in a container with GLIBC
>> 2.27.
>>
>> Apologies for sending it in so late.
> 
> For example GCC_ENABLE_PLUGINS simply does
> 
>       # Check -ldl
>       saved_LIBS="$LIBS"
>       AC_SEARCH_LIBS([dlopen], [dl])
>       if test x"$ac_cv_search_dlopen" = x"-ldl"; then
>         pluginlibs="$pluginlibs -ldl"
>       fi
>       LIBS="$saved_LIBS"
> 
> which I guess would also work for pthread_create?  This would simplify
> the code a bit.

Thanks a lot for the review. I've udpated the patch's content in 
configure.ac per your suggestion. Tested similarly on x86_64 and in a 
container with libc 2.27

 From 00669b600a75743523c358ee41ab999b6e9fa0f6 Mon Sep 17 00:00:00 2001
From: Arthur Cohen <arthur.cohen@embecosm.com>
Date: Fri, 12 Apr 2024 13:52:18 +0200
Subject: [PATCH] rust: Do not link with libdl and libpthread unconditionally

ChangeLog:

	* Makefile.tpl: Add CRAB1_LIBS variable.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Check if -ldl and -lpthread are needed, and if so, add
	them to CRAB1_LIBS.

gcc/rust/ChangeLog:

	* Make-lang.in: Remove overazealous LIBS = -ldl -lpthread line, link
	crab1 against CRAB1_LIBS.
---
  Makefile.in           |   3 +
  Makefile.tpl          |   3 +
  configure             | 154 ++++++++++++++++++++++++++++++++++++++++++
  configure.ac          |  41 +++++++++++
  gcc/rust/Make-lang.in |   6 +-
  5 files changed, 203 insertions(+), 4 deletions(-)

diff --git a/Makefile.in b/Makefile.in
index edb0c8a9a42..1753fb6b862 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -197,6 +197,7 @@ HOST_EXPORTS = \
  	$(BASE_EXPORTS) \
  	CC="$(CC)"; export CC; \
  	ADA_CFLAGS="$(ADA_CFLAGS)"; export ADA_CFLAGS; \
+	CRAB1_LIBS="$(CRAB1_LIBS)"; export CRAB1_LIBS; \
  	CFLAGS="$(CFLAGS)"; export CFLAGS; \
  	CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
  	CXX="$(CXX)"; export CXX; \
@@ -450,6 +451,8 @@ GOCFLAGS = $(CFLAGS)
  GDCFLAGS = @GDCFLAGS@
  GM2FLAGS = $(CFLAGS)

+CRAB1_LIBS = @CRAB1_LIBS@
+
  PKG_CONFIG_PATH = @PKG_CONFIG_PATH@

  GUILE = guile
diff --git a/Makefile.tpl b/Makefile.tpl
index adbcbdd1d57..4aeaad3c1a5 100644
--- a/Makefile.tpl
+++ b/Makefile.tpl
@@ -200,6 +200,7 @@ HOST_EXPORTS = \
  	$(BASE_EXPORTS) \
  	CC="$(CC)"; export CC; \
  	ADA_CFLAGS="$(ADA_CFLAGS)"; export ADA_CFLAGS; \
+	CRAB1_LIBS="$(CRAB1_LIBS)"; export CRAB1_LIBS; \
  	CFLAGS="$(CFLAGS)"; export CFLAGS; \
  	CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
  	CXX="$(CXX)"; export CXX; \
@@ -453,6 +454,8 @@ GOCFLAGS = $(CFLAGS)
  GDCFLAGS = @GDCFLAGS@
  GM2FLAGS = $(CFLAGS)

+CRAB1_LIBS = @CRAB1_LIBS@
+
  PKG_CONFIG_PATH = @PKG_CONFIG_PATH@

  GUILE = guile
diff --git a/configure b/configure
index 02b435c1163..a9ea5258f0f 100755
--- a/configure
+++ b/configure
@@ -690,6 +690,7 @@ extra_host_zlib_configure_flags
  extra_host_libiberty_configure_flags
  stage1_languages
  host_libs_picflag
+CRAB1_LIBS
  PICFLAG
  host_shared
  gcc_host_pie
@@ -8826,6 +8827,139 @@ fi



+# Rust requires -ldl and -lpthread if you are using an old glibc that 
does not include them by
+# default, so we check for them here
+
+missing_rust_dynlibs=none
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library 
containing dlopen" >&5
+$as_echo_n "checking for library containing dlopen... " >&6; }
+if ${ac_cv_search_dlopen+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dlopen ();
+int
+main ()
+{
+return dlopen ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' dl; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_search_dlopen=$ac_res
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext
+  if ${ac_cv_search_dlopen+:} false; then :
+  break
+fi
+done
+if ${ac_cv_search_dlopen+:} false; then :
+
+else
+  ac_cv_search_dlopen=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_dlopen" >&5
+$as_echo "$ac_cv_search_dlopen" >&6; }
+ac_res=$ac_cv_search_dlopen
+if test "$ac_res" != no; then :
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library 
containing pthread_create" >&5
+$as_echo_n "checking for library containing pthread_create... " >&6; }
+if ${ac_cv_search_pthread_create+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char pthread_create ();
+int
+main ()
+{
+return pthread_create ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' pthread; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_search_pthread_create=$ac_res
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext
+  if ${ac_cv_search_pthread_create+:} false; then :
+  break
+fi
+done
+if ${ac_cv_search_pthread_create+:} false; then :
+
+else
+  ac_cv_search_pthread_create=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: 
$ac_cv_search_pthread_create" >&5
+$as_echo "$ac_cv_search_pthread_create" >&6; }
+ac_res=$ac_cv_search_pthread_create
+if test "$ac_res" != no; then :
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+fi
+
+
+if test $ac_cv_search_dlopen = -ldl; then
+    CRAB1_LIBS="$CRAB1_LIBS -ldl"
+elif test $ac_cv_search_dlopen = no; then
+    missing_rust_dynlibs="libdl"
+fi
+
+if test $ac_cv_search_pthread_create = -lpthread; then
+    CRAB1_LIBS="$CRAB1_LIBS -lpthread"
+elif test $ac_cv_search_pthread_crate = no; then
+    missing_rust_dynlibs="$missing_rust_dynlibs, libpthread"
+fi
+
+CRAB1_LIBS="$CRAB1_LIBS"
+
+
  # If we are building PIC/PIE host executables, and we are building 
dependent
  # libs (e.g. GMP) in-tree those libs need to be configured to generate PIC
  # code.
@@ -9066,6 +9200,26 @@ $as_echo "$as_me: WARNING: GDC is required to 
build $language" >&2;}
              ;;
          esac

+        # Disable Rust if we are missing some required C libraries for 
the Rust runtime.
+        case ${add_this_lang}:${language}:${missing_rust_dynlibs} in
+          *:rust:none)
+            # Nothing to do - we're not missing any C libraries
+            ;;
+          yes:rust:*)
+            as_fn_error $? "some C libraries are required to build 
$language: $missing_rust_dynlibs" "$LINENO" 5
+            add_this_lang=unsupported
+            ;;
+          all:rust:*)
+            { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: some C 
libraries are required to build $language: $missing_rust_dynlibs" >&5
+$as_echo "$as_me: WARNING: some C libraries are required to build 
$language: $missing_rust_dynlibs" >&2;}
+            add_this_lang=unsupported
+            ;;
+          *:rust:*)
+            # Silently disable.
+            add_this_lang=unsupported
+            ;;
+        esac
+
          # Disable jit if -enable-host-shared not specified
          # but not if building for Mingw. All code in Windows
          # is position independent code (PIC).
diff --git a/configure.ac b/configure.ac
index 1a19c07a27b..adb738ac346 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2036,6 +2036,28 @@ fi

  AC_SUBST(PICFLAG)

+# Rust requires -ldl and -lpthread if you are using an old glibc that 
does not include them by
+# default, so we check for them here
+
+missing_rust_dynlibs=none
+
+AC_SEARCH_LIBS([dlopen], [dl])
+AC_SEARCH_LIBS([pthread_create], [pthread])
+
+if test $ac_cv_search_dlopen = -ldl; then
+    CRAB1_LIBS="$CRAB1_LIBS -ldl"
+elif test $ac_cv_search_dlopen = no; then
+    missing_rust_dynlibs="libdl"
+fi
+
+if test $ac_cv_search_pthread_create = -lpthread; then
+    CRAB1_LIBS="$CRAB1_LIBS -lpthread"
+elif test $ac_cv_search_pthread_crate = no; then
+    missing_rust_dynlibs="$missing_rust_dynlibs, libpthread"
+fi
+
+AC_SUBST(CRAB1_LIBS, "$CRAB1_LIBS")
+
  # If we are building PIC/PIE host executables, and we are building 
dependent
  # libs (e.g. GMP) in-tree those libs need to be configured to generate PIC
  # code.
@@ -2273,6 +2295,25 @@ if test -d ${srcdir}/gcc; then
              ;;
          esac

+        # Disable Rust if we are missing some required C libraries for 
the Rust runtime.
+        case ${add_this_lang}:${language}:${missing_rust_dynlibs} in
+          *:rust:none)
+            # Nothing to do - we're not missing any C libraries
+            ;;
+          yes:rust:*)
+            AC_MSG_ERROR([some C libraries are required to build 
$language: $missing_rust_dynlibs])
+            add_this_lang=unsupported
+            ;;
+          all:rust:*)
+            AC_MSG_WARN([some C libraries are required to build 
$language: $missing_rust_dynlibs])
+            add_this_lang=unsupported
+            ;;
+          *:rust:*)
+            # Silently disable.
+            add_this_lang=unsupported
+            ;;
+        esac
+
          # Disable jit if -enable-host-shared not specified
          # but not if building for Mingw. All code in Windows
          # is position independent code (PIC).
diff --git a/gcc/rust/Make-lang.in b/gcc/rust/Make-lang.in
index dd94c9b5eab..edcf2ee4c7b 100644
--- a/gcc/rust/Make-lang.in
+++ b/gcc/rust/Make-lang.in
@@ -54,8 +54,6 @@ GCCRS_D_OBJS = \
     rust/rustspec.o \
     $(END)

-LIBS += -ldl -lpthread
-
  gccrs$(exeext): $(GCCRS_D_OBJS) $(EXTRA_GCC_OBJS) libcommon-target.a 
$(LIBDEPS)
  	+$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
  	  $(GCCRS_D_OBJS) $(EXTRA_GCC_OBJS) libcommon-target.a \
@@ -234,7 +232,7 @@ crab1$(exeext): $(RUST_ALL_OBJS) attribs.o 
$(BACKEND) $(LIBDEPS) $(LIBPROC_MACRO
  	@$(call LINK_PROGRESS,$(INDEX.rust),start)
  	+$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
  	      $(RUST_ALL_OBJS) attribs.o $(BACKEND) \
-	      $(LIBS) $(LIBPROC_MACRO_INTERNAL) $(LIBFORMAT_PARSER) 
$(LIBFFI_POLONIUS) \
+	      $(LIBS) $(CRAB1_LIBS) $(LIBPROC_MACRO_INTERNAL) 
$(LIBFORMAT_PARSER) $(LIBFFI_POLONIUS) \
   		  $(BACKENDLIBS)
  	@$(call LINK_PROGRESS,$(INDEX.rust),end)

@@ -496,4 +494,4 @@ rust/libffi_polonius.a: \
  	rust/checks/errors/borrowck/ffi-polonius/Cargo.toml \
  	$(wildcard $(srcdir)/rust/checks/errors/borrowck/ffi-polonius/src/*)
  	cargo build --manifest-path 
$(srcdir)/rust/checks/errors/borrowck/ffi-polonius/Cargo.toml --release 
--target-dir rust/ffi-polonius
-	cp rust/ffi-polonius/release/libffi_polonius.a rust/libffi_polonius.a
\ No newline at end of file
+	cp rust/ffi-polonius/release/libffi_polonius.a rust/libffi_polonius.a
  

On Fri, May 31, 2024 at 12:24 PM Arthur Cohen <arthur.cohen@embecosm.com> wrote:
>
> Hi Richard,
>
> On 4/30/24 09:55, Richard Biener wrote:
> > On Fri, Apr 19, 2024 at 11:49 AM Arthur Cohen <arthur.cohen@embecosm.com> wrote:
> >>
> >> Hi everyone,
> >>
> >> This patch checks for the presence of dlopen and pthread_create in libc. If that is not the
> >> case, we check for the existence of -ldl and -lpthread, as these libraries are required to
> >> link the Rust runtime to our Rust frontend.
> >>
> >> If these libs are not present on the system, then we disable the Rust frontend.
> >>
> >> This was tested on x86_64, in an environment with a recent GLIBC and in a container with GLIBC
> >> 2.27.
> >>
> >> Apologies for sending it in so late.
> >
> > For example GCC_ENABLE_PLUGINS simply does
> >
> >       # Check -ldl
> >       saved_LIBS="$LIBS"
> >       AC_SEARCH_LIBS([dlopen], [dl])
> >       if test x"$ac_cv_search_dlopen" = x"-ldl"; then
> >         pluginlibs="$pluginlibs -ldl"
> >       fi
> >       LIBS="$saved_LIBS"
> >
> > which I guess would also work for pthread_create?  This would simplify
> > the code a bit.
>
> Thanks a lot for the review. I've udpated the patch's content in
> configure.ac per your suggestion. Tested similarly on x86_64 and in a
> container with libc 2.27

LGTM.

Thanks,
Richard.

>  From 00669b600a75743523c358ee41ab999b6e9fa0f6 Mon Sep 17 00:00:00 2001
> From: Arthur Cohen <arthur.cohen@embecosm.com>
> Date: Fri, 12 Apr 2024 13:52:18 +0200
> Subject: [PATCH] rust: Do not link with libdl and libpthread unconditionally
>
> ChangeLog:
>
>         * Makefile.tpl: Add CRAB1_LIBS variable.
>         * Makefile.in: Regenerate.
>         * configure: Regenerate.
>         * configure.ac: Check if -ldl and -lpthread are needed, and if so, add
>         them to CRAB1_LIBS.
>
> gcc/rust/ChangeLog:
>
>         * Make-lang.in: Remove overazealous LIBS = -ldl -lpthread line, link
>         crab1 against CRAB1_LIBS.
> ---
>   Makefile.in           |   3 +
>   Makefile.tpl          |   3 +
>   configure             | 154 ++++++++++++++++++++++++++++++++++++++++++
>   configure.ac          |  41 +++++++++++
>   gcc/rust/Make-lang.in |   6 +-
>   5 files changed, 203 insertions(+), 4 deletions(-)
>
> diff --git a/Makefile.in b/Makefile.in
> index edb0c8a9a42..1753fb6b862 100644
> --- a/Makefile.in
> +++ b/Makefile.in
> @@ -197,6 +197,7 @@ HOST_EXPORTS = \
>         $(BASE_EXPORTS) \
>         CC="$(CC)"; export CC; \
>         ADA_CFLAGS="$(ADA_CFLAGS)"; export ADA_CFLAGS; \
> +       CRAB1_LIBS="$(CRAB1_LIBS)"; export CRAB1_LIBS; \
>         CFLAGS="$(CFLAGS)"; export CFLAGS; \
>         CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
>         CXX="$(CXX)"; export CXX; \
> @@ -450,6 +451,8 @@ GOCFLAGS = $(CFLAGS)
>   GDCFLAGS = @GDCFLAGS@
>   GM2FLAGS = $(CFLAGS)
>
> +CRAB1_LIBS = @CRAB1_LIBS@
> +
>   PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
>
>   GUILE = guile
> diff --git a/Makefile.tpl b/Makefile.tpl
> index adbcbdd1d57..4aeaad3c1a5 100644
> --- a/Makefile.tpl
> +++ b/Makefile.tpl
> @@ -200,6 +200,7 @@ HOST_EXPORTS = \
>         $(BASE_EXPORTS) \
>         CC="$(CC)"; export CC; \
>         ADA_CFLAGS="$(ADA_CFLAGS)"; export ADA_CFLAGS; \
> +       CRAB1_LIBS="$(CRAB1_LIBS)"; export CRAB1_LIBS; \
>         CFLAGS="$(CFLAGS)"; export CFLAGS; \
>         CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
>         CXX="$(CXX)"; export CXX; \
> @@ -453,6 +454,8 @@ GOCFLAGS = $(CFLAGS)
>   GDCFLAGS = @GDCFLAGS@
>   GM2FLAGS = $(CFLAGS)
>
> +CRAB1_LIBS = @CRAB1_LIBS@
> +
>   PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
>
>   GUILE = guile
> diff --git a/configure b/configure
> index 02b435c1163..a9ea5258f0f 100755
> --- a/configure
> +++ b/configure
> @@ -690,6 +690,7 @@ extra_host_zlib_configure_flags
>   extra_host_libiberty_configure_flags
>   stage1_languages
>   host_libs_picflag
> +CRAB1_LIBS
>   PICFLAG
>   host_shared
>   gcc_host_pie
> @@ -8826,6 +8827,139 @@ fi
>
>
>
> +# Rust requires -ldl and -lpthread if you are using an old glibc that
> does not include them by
> +# default, so we check for them here
> +
> +missing_rust_dynlibs=none
> +
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library
> containing dlopen" >&5
> +$as_echo_n "checking for library containing dlopen... " >&6; }
> +if ${ac_cv_search_dlopen+:} false; then :
> +  $as_echo_n "(cached) " >&6
> +else
> +  ac_func_search_save_LIBS=$LIBS
> +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> +/* end confdefs.h.  */
> +
> +/* Override any GCC internal prototype to avoid an error.
> +   Use char because int might match the return type of a GCC
> +   builtin and then its argument prototype would still apply.  */
> +#ifdef __cplusplus
> +extern "C"
> +#endif
> +char dlopen ();
> +int
> +main ()
> +{
> +return dlopen ();
> +  ;
> +  return 0;
> +}
> +_ACEOF
> +for ac_lib in '' dl; do
> +  if test -z "$ac_lib"; then
> +    ac_res="none required"
> +  else
> +    ac_res=-l$ac_lib
> +    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
> +  fi
> +  if ac_fn_c_try_link "$LINENO"; then :
> +  ac_cv_search_dlopen=$ac_res
> +fi
> +rm -f core conftest.err conftest.$ac_objext \
> +    conftest$ac_exeext
> +  if ${ac_cv_search_dlopen+:} false; then :
> +  break
> +fi
> +done
> +if ${ac_cv_search_dlopen+:} false; then :
> +
> +else
> +  ac_cv_search_dlopen=no
> +fi
> +rm conftest.$ac_ext
> +LIBS=$ac_func_search_save_LIBS
> +fi
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_dlopen" >&5
> +$as_echo "$ac_cv_search_dlopen" >&6; }
> +ac_res=$ac_cv_search_dlopen
> +if test "$ac_res" != no; then :
> +  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
> +
> +fi
> +
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library
> containing pthread_create" >&5
> +$as_echo_n "checking for library containing pthread_create... " >&6; }
> +if ${ac_cv_search_pthread_create+:} false; then :
> +  $as_echo_n "(cached) " >&6
> +else
> +  ac_func_search_save_LIBS=$LIBS
> +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> +/* end confdefs.h.  */
> +
> +/* Override any GCC internal prototype to avoid an error.
> +   Use char because int might match the return type of a GCC
> +   builtin and then its argument prototype would still apply.  */
> +#ifdef __cplusplus
> +extern "C"
> +#endif
> +char pthread_create ();
> +int
> +main ()
> +{
> +return pthread_create ();
> +  ;
> +  return 0;
> +}
> +_ACEOF
> +for ac_lib in '' pthread; do
> +  if test -z "$ac_lib"; then
> +    ac_res="none required"
> +  else
> +    ac_res=-l$ac_lib
> +    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
> +  fi
> +  if ac_fn_c_try_link "$LINENO"; then :
> +  ac_cv_search_pthread_create=$ac_res
> +fi
> +rm -f core conftest.err conftest.$ac_objext \
> +    conftest$ac_exeext
> +  if ${ac_cv_search_pthread_create+:} false; then :
> +  break
> +fi
> +done
> +if ${ac_cv_search_pthread_create+:} false; then :
> +
> +else
> +  ac_cv_search_pthread_create=no
> +fi
> +rm conftest.$ac_ext
> +LIBS=$ac_func_search_save_LIBS
> +fi
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result:
> $ac_cv_search_pthread_create" >&5
> +$as_echo "$ac_cv_search_pthread_create" >&6; }
> +ac_res=$ac_cv_search_pthread_create
> +if test "$ac_res" != no; then :
> +  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
> +
> +fi
> +
> +
> +if test $ac_cv_search_dlopen = -ldl; then
> +    CRAB1_LIBS="$CRAB1_LIBS -ldl"
> +elif test $ac_cv_search_dlopen = no; then
> +    missing_rust_dynlibs="libdl"
> +fi
> +
> +if test $ac_cv_search_pthread_create = -lpthread; then
> +    CRAB1_LIBS="$CRAB1_LIBS -lpthread"
> +elif test $ac_cv_search_pthread_crate = no; then
> +    missing_rust_dynlibs="$missing_rust_dynlibs, libpthread"
> +fi
> +
> +CRAB1_LIBS="$CRAB1_LIBS"
> +
> +
>   # If we are building PIC/PIE host executables, and we are building
> dependent
>   # libs (e.g. GMP) in-tree those libs need to be configured to generate PIC
>   # code.
> @@ -9066,6 +9200,26 @@ $as_echo "$as_me: WARNING: GDC is required to
> build $language" >&2;}
>               ;;
>           esac
>
> +        # Disable Rust if we are missing some required C libraries for
> the Rust runtime.
> +        case ${add_this_lang}:${language}:${missing_rust_dynlibs} in
> +          *:rust:none)
> +            # Nothing to do - we're not missing any C libraries
> +            ;;
> +          yes:rust:*)
> +            as_fn_error $? "some C libraries are required to build
> $language: $missing_rust_dynlibs" "$LINENO" 5
> +            add_this_lang=unsupported
> +            ;;
> +          all:rust:*)
> +            { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: some C
> libraries are required to build $language: $missing_rust_dynlibs" >&5
> +$as_echo "$as_me: WARNING: some C libraries are required to build
> $language: $missing_rust_dynlibs" >&2;}
> +            add_this_lang=unsupported
> +            ;;
> +          *:rust:*)
> +            # Silently disable.
> +            add_this_lang=unsupported
> +            ;;
> +        esac
> +
>           # Disable jit if -enable-host-shared not specified
>           # but not if building for Mingw. All code in Windows
>           # is position independent code (PIC).
> diff --git a/configure.ac b/configure.ac
> index 1a19c07a27b..adb738ac346 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -2036,6 +2036,28 @@ fi
>
>   AC_SUBST(PICFLAG)
>
> +# Rust requires -ldl and -lpthread if you are using an old glibc that
> does not include them by
> +# default, so we check for them here
> +
> +missing_rust_dynlibs=none
> +
> +AC_SEARCH_LIBS([dlopen], [dl])
> +AC_SEARCH_LIBS([pthread_create], [pthread])
> +
> +if test $ac_cv_search_dlopen = -ldl; then
> +    CRAB1_LIBS="$CRAB1_LIBS -ldl"
> +elif test $ac_cv_search_dlopen = no; then
> +    missing_rust_dynlibs="libdl"
> +fi
> +
> +if test $ac_cv_search_pthread_create = -lpthread; then
> +    CRAB1_LIBS="$CRAB1_LIBS -lpthread"
> +elif test $ac_cv_search_pthread_crate = no; then
> +    missing_rust_dynlibs="$missing_rust_dynlibs, libpthread"
> +fi
> +
> +AC_SUBST(CRAB1_LIBS, "$CRAB1_LIBS")
> +
>   # If we are building PIC/PIE host executables, and we are building
> dependent
>   # libs (e.g. GMP) in-tree those libs need to be configured to generate PIC
>   # code.
> @@ -2273,6 +2295,25 @@ if test -d ${srcdir}/gcc; then
>               ;;
>           esac
>
> +        # Disable Rust if we are missing some required C libraries for
> the Rust runtime.
> +        case ${add_this_lang}:${language}:${missing_rust_dynlibs} in
> +          *:rust:none)
> +            # Nothing to do - we're not missing any C libraries
> +            ;;
> +          yes:rust:*)
> +            AC_MSG_ERROR([some C libraries are required to build
> $language: $missing_rust_dynlibs])
> +            add_this_lang=unsupported
> +            ;;
> +          all:rust:*)
> +            AC_MSG_WARN([some C libraries are required to build
> $language: $missing_rust_dynlibs])
> +            add_this_lang=unsupported
> +            ;;
> +          *:rust:*)
> +            # Silently disable.
> +            add_this_lang=unsupported
> +            ;;
> +        esac
> +
>           # Disable jit if -enable-host-shared not specified
>           # but not if building for Mingw. All code in Windows
>           # is position independent code (PIC).
> diff --git a/gcc/rust/Make-lang.in b/gcc/rust/Make-lang.in
> index dd94c9b5eab..edcf2ee4c7b 100644
> --- a/gcc/rust/Make-lang.in
> +++ b/gcc/rust/Make-lang.in
> @@ -54,8 +54,6 @@ GCCRS_D_OBJS = \
>      rust/rustspec.o \
>      $(END)
>
> -LIBS += -ldl -lpthread
> -
>   gccrs$(exeext): $(GCCRS_D_OBJS) $(EXTRA_GCC_OBJS) libcommon-target.a
> $(LIBDEPS)
>         +$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
>           $(GCCRS_D_OBJS) $(EXTRA_GCC_OBJS) libcommon-target.a \
> @@ -234,7 +232,7 @@ crab1$(exeext): $(RUST_ALL_OBJS) attribs.o
> $(BACKEND) $(LIBDEPS) $(LIBPROC_MACRO
>         @$(call LINK_PROGRESS,$(INDEX.rust),start)
>         +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
>               $(RUST_ALL_OBJS) attribs.o $(BACKEND) \
> -             $(LIBS) $(LIBPROC_MACRO_INTERNAL) $(LIBFORMAT_PARSER)
> $(LIBFFI_POLONIUS) \
> +             $(LIBS) $(CRAB1_LIBS) $(LIBPROC_MACRO_INTERNAL)
> $(LIBFORMAT_PARSER) $(LIBFFI_POLONIUS) \
>                   $(BACKENDLIBS)
>         @$(call LINK_PROGRESS,$(INDEX.rust),end)
>
> @@ -496,4 +494,4 @@ rust/libffi_polonius.a: \
>         rust/checks/errors/borrowck/ffi-polonius/Cargo.toml \
>         $(wildcard $(srcdir)/rust/checks/errors/borrowck/ffi-polonius/src/*)
>         cargo build --manifest-path
> $(srcdir)/rust/checks/errors/borrowck/ffi-polonius/Cargo.toml --release
> --target-dir rust/ffi-polonius
> -       cp rust/ffi-polonius/release/libffi_polonius.a rust/libffi_polonius.a
> \ No newline at end of file
> +       cp rust/ffi-polonius/release/libffi_polonius.a rust/libffi_polonius.a
> --
> 2.42.0
>
  

Thanks Richi!

Tested again and pushed on trunk.

Best,

Arthur

On 5/31/24 15:02, Richard Biener wrote:
> On Fri, May 31, 2024 at 12:24 PM Arthur Cohen <arthur.cohen@embecosm.com> wrote:
>>
>> Hi Richard,
>>
>> On 4/30/24 09:55, Richard Biener wrote:
>>> On Fri, Apr 19, 2024 at 11:49 AM Arthur Cohen <arthur.cohen@embecosm.com> wrote:
>>>>
>>>> Hi everyone,
>>>>
>>>> This patch checks for the presence of dlopen and pthread_create in libc. If that is not the
>>>> case, we check for the existence of -ldl and -lpthread, as these libraries are required to
>>>> link the Rust runtime to our Rust frontend.
>>>>
>>>> If these libs are not present on the system, then we disable the Rust frontend.
>>>>
>>>> This was tested on x86_64, in an environment with a recent GLIBC and in a container with GLIBC
>>>> 2.27.
>>>>
>>>> Apologies for sending it in so late.
>>>
>>> For example GCC_ENABLE_PLUGINS simply does
>>>
>>>        # Check -ldl
>>>        saved_LIBS="$LIBS"
>>>        AC_SEARCH_LIBS([dlopen], [dl])
>>>        if test x"$ac_cv_search_dlopen" = x"-ldl"; then
>>>          pluginlibs="$pluginlibs -ldl"
>>>        fi
>>>        LIBS="$saved_LIBS"
>>>
>>> which I guess would also work for pthread_create?  This would simplify
>>> the code a bit.
>>
>> Thanks a lot for the review. I've udpated the patch's content in
>> configure.ac per your suggestion. Tested similarly on x86_64 and in a
>> container with libc 2.27
> 
> LGTM.
> 
> Thanks,
> Richard.
> 
>>   From 00669b600a75743523c358ee41ab999b6e9fa0f6 Mon Sep 17 00:00:00 2001
>> From: Arthur Cohen <arthur.cohen@embecosm.com>
>> Date: Fri, 12 Apr 2024 13:52:18 +0200
>> Subject: [PATCH] rust: Do not link with libdl and libpthread unconditionally
>>
>> ChangeLog:
>>
>>          * Makefile.tpl: Add CRAB1_LIBS variable.
>>          * Makefile.in: Regenerate.
>>          * configure: Regenerate.
>>          * configure.ac: Check if -ldl and -lpthread are needed, and if so, add
>>          them to CRAB1_LIBS.
>>
>> gcc/rust/ChangeLog:
>>
>>          * Make-lang.in: Remove overazealous LIBS = -ldl -lpthread line, link
>>          crab1 against CRAB1_LIBS.
>> ---
>>    Makefile.in           |   3 +
>>    Makefile.tpl          |   3 +
>>    configure             | 154 ++++++++++++++++++++++++++++++++++++++++++
>>    configure.ac          |  41 +++++++++++
>>    gcc/rust/Make-lang.in |   6 +-
>>    5 files changed, 203 insertions(+), 4 deletions(-)
>>
>> diff --git a/Makefile.in b/Makefile.in
>> index edb0c8a9a42..1753fb6b862 100644
>> --- a/Makefile.in
>> +++ b/Makefile.in
>> @@ -197,6 +197,7 @@ HOST_EXPORTS = \
>>          $(BASE_EXPORTS) \
>>          CC="$(CC)"; export CC; \
>>          ADA_CFLAGS="$(ADA_CFLAGS)"; export ADA_CFLAGS; \
>> +       CRAB1_LIBS="$(CRAB1_LIBS)"; export CRAB1_LIBS; \
>>          CFLAGS="$(CFLAGS)"; export CFLAGS; \
>>          CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
>>          CXX="$(CXX)"; export CXX; \
>> @@ -450,6 +451,8 @@ GOCFLAGS = $(CFLAGS)
>>    GDCFLAGS = @GDCFLAGS@
>>    GM2FLAGS = $(CFLAGS)
>>
>> +CRAB1_LIBS = @CRAB1_LIBS@
>> +
>>    PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
>>
>>    GUILE = guile
>> diff --git a/Makefile.tpl b/Makefile.tpl
>> index adbcbdd1d57..4aeaad3c1a5 100644
>> --- a/Makefile.tpl
>> +++ b/Makefile.tpl
>> @@ -200,6 +200,7 @@ HOST_EXPORTS = \
>>          $(BASE_EXPORTS) \
>>          CC="$(CC)"; export CC; \
>>          ADA_CFLAGS="$(ADA_CFLAGS)"; export ADA_CFLAGS; \
>> +       CRAB1_LIBS="$(CRAB1_LIBS)"; export CRAB1_LIBS; \
>>          CFLAGS="$(CFLAGS)"; export CFLAGS; \
>>          CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
>>          CXX="$(CXX)"; export CXX; \
>> @@ -453,6 +454,8 @@ GOCFLAGS = $(CFLAGS)
>>    GDCFLAGS = @GDCFLAGS@
>>    GM2FLAGS = $(CFLAGS)
>>
>> +CRAB1_LIBS = @CRAB1_LIBS@
>> +
>>    PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
>>
>>    GUILE = guile
>> diff --git a/configure b/configure
>> index 02b435c1163..a9ea5258f0f 100755
>> --- a/configure
>> +++ b/configure
>> @@ -690,6 +690,7 @@ extra_host_zlib_configure_flags
>>    extra_host_libiberty_configure_flags
>>    stage1_languages
>>    host_libs_picflag
>> +CRAB1_LIBS
>>    PICFLAG
>>    host_shared
>>    gcc_host_pie
>> @@ -8826,6 +8827,139 @@ fi
>>
>>
>>
>> +# Rust requires -ldl and -lpthread if you are using an old glibc that
>> does not include them by
>> +# default, so we check for them here
>> +
>> +missing_rust_dynlibs=none
>> +
>> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library
>> containing dlopen" >&5
>> +$as_echo_n "checking for library containing dlopen... " >&6; }
>> +if ${ac_cv_search_dlopen+:} false; then :
>> +  $as_echo_n "(cached) " >&6
>> +else
>> +  ac_func_search_save_LIBS=$LIBS
>> +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
>> +/* end confdefs.h.  */
>> +
>> +/* Override any GCC internal prototype to avoid an error.
>> +   Use char because int might match the return type of a GCC
>> +   builtin and then its argument prototype would still apply.  */
>> +#ifdef __cplusplus
>> +extern "C"
>> +#endif
>> +char dlopen ();
>> +int
>> +main ()
>> +{
>> +return dlopen ();
>> +  ;
>> +  return 0;
>> +}
>> +_ACEOF
>> +for ac_lib in '' dl; do
>> +  if test -z "$ac_lib"; then
>> +    ac_res="none required"
>> +  else
>> +    ac_res=-l$ac_lib
>> +    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
>> +  fi
>> +  if ac_fn_c_try_link "$LINENO"; then :
>> +  ac_cv_search_dlopen=$ac_res
>> +fi
>> +rm -f core conftest.err conftest.$ac_objext \
>> +    conftest$ac_exeext
>> +  if ${ac_cv_search_dlopen+:} false; then :
>> +  break
>> +fi
>> +done
>> +if ${ac_cv_search_dlopen+:} false; then :
>> +
>> +else
>> +  ac_cv_search_dlopen=no
>> +fi
>> +rm conftest.$ac_ext
>> +LIBS=$ac_func_search_save_LIBS
>> +fi
>> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_dlopen" >&5
>> +$as_echo "$ac_cv_search_dlopen" >&6; }
>> +ac_res=$ac_cv_search_dlopen
>> +if test "$ac_res" != no; then :
>> +  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
>> +
>> +fi
>> +
>> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library
>> containing pthread_create" >&5
>> +$as_echo_n "checking for library containing pthread_create... " >&6; }
>> +if ${ac_cv_search_pthread_create+:} false; then :
>> +  $as_echo_n "(cached) " >&6
>> +else
>> +  ac_func_search_save_LIBS=$LIBS
>> +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
>> +/* end confdefs.h.  */
>> +
>> +/* Override any GCC internal prototype to avoid an error.
>> +   Use char because int might match the return type of a GCC
>> +   builtin and then its argument prototype would still apply.  */
>> +#ifdef __cplusplus
>> +extern "C"
>> +#endif
>> +char pthread_create ();
>> +int
>> +main ()
>> +{
>> +return pthread_create ();
>> +  ;
>> +  return 0;
>> +}
>> +_ACEOF
>> +for ac_lib in '' pthread; do
>> +  if test -z "$ac_lib"; then
>> +    ac_res="none required"
>> +  else
>> +    ac_res=-l$ac_lib
>> +    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
>> +  fi
>> +  if ac_fn_c_try_link "$LINENO"; then :
>> +  ac_cv_search_pthread_create=$ac_res
>> +fi
>> +rm -f core conftest.err conftest.$ac_objext \
>> +    conftest$ac_exeext
>> +  if ${ac_cv_search_pthread_create+:} false; then :
>> +  break
>> +fi
>> +done
>> +if ${ac_cv_search_pthread_create+:} false; then :
>> +
>> +else
>> +  ac_cv_search_pthread_create=no
>> +fi
>> +rm conftest.$ac_ext
>> +LIBS=$ac_func_search_save_LIBS
>> +fi
>> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result:
>> $ac_cv_search_pthread_create" >&5
>> +$as_echo "$ac_cv_search_pthread_create" >&6; }
>> +ac_res=$ac_cv_search_pthread_create
>> +if test "$ac_res" != no; then :
>> +  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
>> +
>> +fi
>> +
>> +
>> +if test $ac_cv_search_dlopen = -ldl; then
>> +    CRAB1_LIBS="$CRAB1_LIBS -ldl"
>> +elif test $ac_cv_search_dlopen = no; then
>> +    missing_rust_dynlibs="libdl"
>> +fi
>> +
>> +if test $ac_cv_search_pthread_create = -lpthread; then
>> +    CRAB1_LIBS="$CRAB1_LIBS -lpthread"
>> +elif test $ac_cv_search_pthread_crate = no; then
>> +    missing_rust_dynlibs="$missing_rust_dynlibs, libpthread"
>> +fi
>> +
>> +CRAB1_LIBS="$CRAB1_LIBS"
>> +
>> +
>>    # If we are building PIC/PIE host executables, and we are building
>> dependent
>>    # libs (e.g. GMP) in-tree those libs need to be configured to generate PIC
>>    # code.
>> @@ -9066,6 +9200,26 @@ $as_echo "$as_me: WARNING: GDC is required to
>> build $language" >&2;}
>>                ;;
>>            esac
>>
>> +        # Disable Rust if we are missing some required C libraries for
>> the Rust runtime.
>> +        case ${add_this_lang}:${language}:${missing_rust_dynlibs} in
>> +          *:rust:none)
>> +            # Nothing to do - we're not missing any C libraries
>> +            ;;
>> +          yes:rust:*)
>> +            as_fn_error $? "some C libraries are required to build
>> $language: $missing_rust_dynlibs" "$LINENO" 5
>> +            add_this_lang=unsupported
>> +            ;;
>> +          all:rust:*)
>> +            { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: some C
>> libraries are required to build $language: $missing_rust_dynlibs" >&5
>> +$as_echo "$as_me: WARNING: some C libraries are required to build
>> $language: $missing_rust_dynlibs" >&2;}
>> +            add_this_lang=unsupported
>> +            ;;
>> +          *:rust:*)
>> +            # Silently disable.
>> +            add_this_lang=unsupported
>> +            ;;
>> +        esac
>> +
>>            # Disable jit if -enable-host-shared not specified
>>            # but not if building for Mingw. All code in Windows
>>            # is position independent code (PIC).
>> diff --git a/configure.ac b/configure.ac
>> index 1a19c07a27b..adb738ac346 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -2036,6 +2036,28 @@ fi
>>
>>    AC_SUBST(PICFLAG)
>>
>> +# Rust requires -ldl and -lpthread if you are using an old glibc that
>> does not include them by
>> +# default, so we check for them here
>> +
>> +missing_rust_dynlibs=none
>> +
>> +AC_SEARCH_LIBS([dlopen], [dl])
>> +AC_SEARCH_LIBS([pthread_create], [pthread])
>> +
>> +if test $ac_cv_search_dlopen = -ldl; then
>> +    CRAB1_LIBS="$CRAB1_LIBS -ldl"
>> +elif test $ac_cv_search_dlopen = no; then
>> +    missing_rust_dynlibs="libdl"
>> +fi
>> +
>> +if test $ac_cv_search_pthread_create = -lpthread; then
>> +    CRAB1_LIBS="$CRAB1_LIBS -lpthread"
>> +elif test $ac_cv_search_pthread_crate = no; then
>> +    missing_rust_dynlibs="$missing_rust_dynlibs, libpthread"
>> +fi
>> +
>> +AC_SUBST(CRAB1_LIBS, "$CRAB1_LIBS")
>> +
>>    # If we are building PIC/PIE host executables, and we are building
>> dependent
>>    # libs (e.g. GMP) in-tree those libs need to be configured to generate PIC
>>    # code.
>> @@ -2273,6 +2295,25 @@ if test -d ${srcdir}/gcc; then
>>                ;;
>>            esac
>>
>> +        # Disable Rust if we are missing some required C libraries for
>> the Rust runtime.
>> +        case ${add_this_lang}:${language}:${missing_rust_dynlibs} in
>> +          *:rust:none)
>> +            # Nothing to do - we're not missing any C libraries
>> +            ;;
>> +          yes:rust:*)
>> +            AC_MSG_ERROR([some C libraries are required to build
>> $language: $missing_rust_dynlibs])
>> +            add_this_lang=unsupported
>> +            ;;
>> +          all:rust:*)
>> +            AC_MSG_WARN([some C libraries are required to build
>> $language: $missing_rust_dynlibs])
>> +            add_this_lang=unsupported
>> +            ;;
>> +          *:rust:*)
>> +            # Silently disable.
>> +            add_this_lang=unsupported
>> +            ;;
>> +        esac
>> +
>>            # Disable jit if -enable-host-shared not specified
>>            # but not if building for Mingw. All code in Windows
>>            # is position independent code (PIC).
>> diff --git a/gcc/rust/Make-lang.in b/gcc/rust/Make-lang.in
>> index dd94c9b5eab..edcf2ee4c7b 100644
>> --- a/gcc/rust/Make-lang.in
>> +++ b/gcc/rust/Make-lang.in
>> @@ -54,8 +54,6 @@ GCCRS_D_OBJS = \
>>       rust/rustspec.o \
>>       $(END)
>>
>> -LIBS += -ldl -lpthread
>> -
>>    gccrs$(exeext): $(GCCRS_D_OBJS) $(EXTRA_GCC_OBJS) libcommon-target.a
>> $(LIBDEPS)
>>          +$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
>>            $(GCCRS_D_OBJS) $(EXTRA_GCC_OBJS) libcommon-target.a \
>> @@ -234,7 +232,7 @@ crab1$(exeext): $(RUST_ALL_OBJS) attribs.o
>> $(BACKEND) $(LIBDEPS) $(LIBPROC_MACRO
>>          @$(call LINK_PROGRESS,$(INDEX.rust),start)
>>          +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
>>                $(RUST_ALL_OBJS) attribs.o $(BACKEND) \
>> -             $(LIBS) $(LIBPROC_MACRO_INTERNAL) $(LIBFORMAT_PARSER)
>> $(LIBFFI_POLONIUS) \
>> +             $(LIBS) $(CRAB1_LIBS) $(LIBPROC_MACRO_INTERNAL)
>> $(LIBFORMAT_PARSER) $(LIBFFI_POLONIUS) \
>>                    $(BACKENDLIBS)
>>          @$(call LINK_PROGRESS,$(INDEX.rust),end)
>>
>> @@ -496,4 +494,4 @@ rust/libffi_polonius.a: \
>>          rust/checks/errors/borrowck/ffi-polonius/Cargo.toml \
>>          $(wildcard $(srcdir)/rust/checks/errors/borrowck/ffi-polonius/src/*)
>>          cargo build --manifest-path
>> $(srcdir)/rust/checks/errors/borrowck/ffi-polonius/Cargo.toml --release
>> --target-dir rust/ffi-polonius
>> -       cp rust/ffi-polonius/release/libffi_polonius.a rust/libffi_polonius.a
>> \ No newline at end of file
>> +       cp rust/ffi-polonius/release/libffi_polonius.a rust/libffi_polonius.a
>> --
>> 2.42.0
>>

-- 
Arthur Cohen <arthur.cohen@embecosm.com>

Toolchain Engineer

Embecosm GmbH

Geschäftsführer: Jeremy Bennett
Niederlassung: Nürnberg
Handelsregister: HR-B 36368
www.embecosm.de

Fürther Str. 27
90429 Nürnberg


Tel.: 091 - 128 707 040
Fax: 091 - 128 707 077
  

On Tue, Jun 11, 2024 at 11:21 AM Arthur Cohen <arthur.cohen@embecosm.com> wrote:
>
> Thanks Richi!
>
> Tested again and pushed on trunk.


This patch introduced a couple of errors during ./configure:

checking for library containing dlopen... none required
checking for library containing pthread_create... none required
/git/gcc/configure: line 8997: test: too many arguments
/git/gcc/configure: line 8999: test: too many arguments
/git/gcc/configure: line 9003: test: too many arguments
/git/gcc/configure: line 9005: test: =: unary operator expected

You have to wrap arguments of the test with double quotes.

Uros.

> Best,
>
> Arthur
>
> On 5/31/24 15:02, Richard Biener wrote:
> > On Fri, May 31, 2024 at 12:24 PM Arthur Cohen <arthur.cohen@embecosm.com> wrote:
> >>
> >> Hi Richard,
> >>
> >> On 4/30/24 09:55, Richard Biener wrote:
> >>> On Fri, Apr 19, 2024 at 11:49 AM Arthur Cohen <arthur.cohen@embecosm.com> wrote:
> >>>>
> >>>> Hi everyone,
> >>>>
> >>>> This patch checks for the presence of dlopen and pthread_create in libc. If that is not the
> >>>> case, we check for the existence of -ldl and -lpthread, as these libraries are required to
> >>>> link the Rust runtime to our Rust frontend.
> >>>>
> >>>> If these libs are not present on the system, then we disable the Rust frontend.
> >>>>
> >>>> This was tested on x86_64, in an environment with a recent GLIBC and in a container with GLIBC
> >>>> 2.27.
> >>>>
> >>>> Apologies for sending it in so late.
> >>>
> >>> For example GCC_ENABLE_PLUGINS simply does
> >>>
> >>>        # Check -ldl
> >>>        saved_LIBS="$LIBS"
> >>>        AC_SEARCH_LIBS([dlopen], [dl])
> >>>        if test x"$ac_cv_search_dlopen" = x"-ldl"; then
> >>>          pluginlibs="$pluginlibs -ldl"
> >>>        fi
> >>>        LIBS="$saved_LIBS"
> >>>
> >>> which I guess would also work for pthread_create?  This would simplify
> >>> the code a bit.
> >>
> >> Thanks a lot for the review. I've udpated the patch's content in
> >> configure.ac per your suggestion. Tested similarly on x86_64 and in a
> >> container with libc 2.27
> >
> > LGTM.
> >
> > Thanks,
> > Richard.
> >
> >>   From 00669b600a75743523c358ee41ab999b6e9fa0f6 Mon Sep 17 00:00:00 2001
> >> From: Arthur Cohen <arthur.cohen@embecosm.com>
> >> Date: Fri, 12 Apr 2024 13:52:18 +0200
> >> Subject: [PATCH] rust: Do not link with libdl and libpthread unconditionally
> >>
> >> ChangeLog:
> >>
> >>          * Makefile.tpl: Add CRAB1_LIBS variable.
> >>          * Makefile.in: Regenerate.
> >>          * configure: Regenerate.
> >>          * configure.ac: Check if -ldl and -lpthread are needed, and if so, add
> >>          them to CRAB1_LIBS.
> >>
> >> gcc/rust/ChangeLog:
> >>
> >>          * Make-lang.in: Remove overazealous LIBS = -ldl -lpthread line, link
> >>          crab1 against CRAB1_LIBS.
> >> ---
> >>    Makefile.in           |   3 +
> >>    Makefile.tpl          |   3 +
> >>    configure             | 154 ++++++++++++++++++++++++++++++++++++++++++
> >>    configure.ac          |  41 +++++++++++
> >>    gcc/rust/Make-lang.in |   6 +-
> >>    5 files changed, 203 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/Makefile.in b/Makefile.in
> >> index edb0c8a9a42..1753fb6b862 100644
> >> --- a/Makefile.in
> >> +++ b/Makefile.in
> >> @@ -197,6 +197,7 @@ HOST_EXPORTS = \
> >>          $(BASE_EXPORTS) \
> >>          CC="$(CC)"; export CC; \
> >>          ADA_CFLAGS="$(ADA_CFLAGS)"; export ADA_CFLAGS; \
> >> +       CRAB1_LIBS="$(CRAB1_LIBS)"; export CRAB1_LIBS; \
> >>          CFLAGS="$(CFLAGS)"; export CFLAGS; \
> >>          CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
> >>          CXX="$(CXX)"; export CXX; \
> >> @@ -450,6 +451,8 @@ GOCFLAGS = $(CFLAGS)
> >>    GDCFLAGS = @GDCFLAGS@
> >>    GM2FLAGS = $(CFLAGS)
> >>
> >> +CRAB1_LIBS = @CRAB1_LIBS@
> >> +
> >>    PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
> >>
> >>    GUILE = guile
> >> diff --git a/Makefile.tpl b/Makefile.tpl
> >> index adbcbdd1d57..4aeaad3c1a5 100644
> >> --- a/Makefile.tpl
> >> +++ b/Makefile.tpl
> >> @@ -200,6 +200,7 @@ HOST_EXPORTS = \
> >>          $(BASE_EXPORTS) \
> >>          CC="$(CC)"; export CC; \
> >>          ADA_CFLAGS="$(ADA_CFLAGS)"; export ADA_CFLAGS; \
> >> +       CRAB1_LIBS="$(CRAB1_LIBS)"; export CRAB1_LIBS; \
> >>          CFLAGS="$(CFLAGS)"; export CFLAGS; \
> >>          CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
> >>          CXX="$(CXX)"; export CXX; \
> >> @@ -453,6 +454,8 @@ GOCFLAGS = $(CFLAGS)
> >>    GDCFLAGS = @GDCFLAGS@
> >>    GM2FLAGS = $(CFLAGS)
> >>
> >> +CRAB1_LIBS = @CRAB1_LIBS@
> >> +
> >>    PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
> >>
> >>    GUILE = guile
> >> diff --git a/configure b/configure
> >> index 02b435c1163..a9ea5258f0f 100755
> >> --- a/configure
> >> +++ b/configure
> >> @@ -690,6 +690,7 @@ extra_host_zlib_configure_flags
> >>    extra_host_libiberty_configure_flags
> >>    stage1_languages
> >>    host_libs_picflag
> >> +CRAB1_LIBS
> >>    PICFLAG
> >>    host_shared
> >>    gcc_host_pie
> >> @@ -8826,6 +8827,139 @@ fi
> >>
> >>
> >>
> >> +# Rust requires -ldl and -lpthread if you are using an old glibc that
> >> does not include them by
> >> +# default, so we check for them here
> >> +
> >> +missing_rust_dynlibs=none
> >> +
> >> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library
> >> containing dlopen" >&5
> >> +$as_echo_n "checking for library containing dlopen... " >&6; }
> >> +if ${ac_cv_search_dlopen+:} false; then :
> >> +  $as_echo_n "(cached) " >&6
> >> +else
> >> +  ac_func_search_save_LIBS=$LIBS
> >> +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> >> +/* end confdefs.h.  */
> >> +
> >> +/* Override any GCC internal prototype to avoid an error.
> >> +   Use char because int might match the return type of a GCC
> >> +   builtin and then its argument prototype would still apply.  */
> >> +#ifdef __cplusplus
> >> +extern "C"
> >> +#endif
> >> +char dlopen ();
> >> +int
> >> +main ()
> >> +{
> >> +return dlopen ();
> >> +  ;
> >> +  return 0;
> >> +}
> >> +_ACEOF
> >> +for ac_lib in '' dl; do
> >> +  if test -z "$ac_lib"; then
> >> +    ac_res="none required"
> >> +  else
> >> +    ac_res=-l$ac_lib
> >> +    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
> >> +  fi
> >> +  if ac_fn_c_try_link "$LINENO"; then :
> >> +  ac_cv_search_dlopen=$ac_res
> >> +fi
> >> +rm -f core conftest.err conftest.$ac_objext \
> >> +    conftest$ac_exeext
> >> +  if ${ac_cv_search_dlopen+:} false; then :
> >> +  break
> >> +fi
> >> +done
> >> +if ${ac_cv_search_dlopen+:} false; then :
> >> +
> >> +else
> >> +  ac_cv_search_dlopen=no
> >> +fi
> >> +rm conftest.$ac_ext
> >> +LIBS=$ac_func_search_save_LIBS
> >> +fi
> >> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_dlopen" >&5
> >> +$as_echo "$ac_cv_search_dlopen" >&6; }
> >> +ac_res=$ac_cv_search_dlopen
> >> +if test "$ac_res" != no; then :
> >> +  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
> >> +
> >> +fi
> >> +
> >> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library
> >> containing pthread_create" >&5
> >> +$as_echo_n "checking for library containing pthread_create... " >&6; }
> >> +if ${ac_cv_search_pthread_create+:} false; then :
> >> +  $as_echo_n "(cached) " >&6
> >> +else
> >> +  ac_func_search_save_LIBS=$LIBS
> >> +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> >> +/* end confdefs.h.  */
> >> +
> >> +/* Override any GCC internal prototype to avoid an error.
> >> +   Use char because int might match the return type of a GCC
> >> +   builtin and then its argument prototype would still apply.  */
> >> +#ifdef __cplusplus
> >> +extern "C"
> >> +#endif
> >> +char pthread_create ();
> >> +int
> >> +main ()
> >> +{
> >> +return pthread_create ();
> >> +  ;
> >> +  return 0;
> >> +}
> >> +_ACEOF
> >> +for ac_lib in '' pthread; do
> >> +  if test -z "$ac_lib"; then
> >> +    ac_res="none required"
> >> +  else
> >> +    ac_res=-l$ac_lib
> >> +    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
> >> +  fi
> >> +  if ac_fn_c_try_link "$LINENO"; then :
> >> +  ac_cv_search_pthread_create=$ac_res
> >> +fi
> >> +rm -f core conftest.err conftest.$ac_objext \
> >> +    conftest$ac_exeext
> >> +  if ${ac_cv_search_pthread_create+:} false; then :
> >> +  break
> >> +fi
> >> +done
> >> +if ${ac_cv_search_pthread_create+:} false; then :
> >> +
> >> +else
> >> +  ac_cv_search_pthread_create=no
> >> +fi
> >> +rm conftest.$ac_ext
> >> +LIBS=$ac_func_search_save_LIBS
> >> +fi
> >> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result:
> >> $ac_cv_search_pthread_create" >&5
> >> +$as_echo "$ac_cv_search_pthread_create" >&6; }
> >> +ac_res=$ac_cv_search_pthread_create
> >> +if test "$ac_res" != no; then :
> >> +  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
> >> +
> >> +fi
> >> +
> >> +
> >> +if test $ac_cv_search_dlopen = -ldl; then
> >> +    CRAB1_LIBS="$CRAB1_LIBS -ldl"
> >> +elif test $ac_cv_search_dlopen = no; then
> >> +    missing_rust_dynlibs="libdl"
> >> +fi
> >> +
> >> +if test $ac_cv_search_pthread_create = -lpthread; then
> >> +    CRAB1_LIBS="$CRAB1_LIBS -lpthread"
> >> +elif test $ac_cv_search_pthread_crate = no; then
> >> +    missing_rust_dynlibs="$missing_rust_dynlibs, libpthread"
> >> +fi
> >> +
> >> +CRAB1_LIBS="$CRAB1_LIBS"
> >> +
> >> +
> >>    # If we are building PIC/PIE host executables, and we are building
> >> dependent
> >>    # libs (e.g. GMP) in-tree those libs need to be configured to generate PIC
> >>    # code.
> >> @@ -9066,6 +9200,26 @@ $as_echo "$as_me: WARNING: GDC is required to
> >> build $language" >&2;}
> >>                ;;
> >>            esac
> >>
> >> +        # Disable Rust if we are missing some required C libraries for
> >> the Rust runtime.
> >> +        case ${add_this_lang}:${language}:${missing_rust_dynlibs} in
> >> +          *:rust:none)
> >> +            # Nothing to do - we're not missing any C libraries
> >> +            ;;
> >> +          yes:rust:*)
> >> +            as_fn_error $? "some C libraries are required to build
> >> $language: $missing_rust_dynlibs" "$LINENO" 5
> >> +            add_this_lang=unsupported
> >> +            ;;
> >> +          all:rust:*)
> >> +            { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: some C
> >> libraries are required to build $language: $missing_rust_dynlibs" >&5
> >> +$as_echo "$as_me: WARNING: some C libraries are required to build
> >> $language: $missing_rust_dynlibs" >&2;}
> >> +            add_this_lang=unsupported
> >> +            ;;
> >> +          *:rust:*)
> >> +            # Silently disable.
> >> +            add_this_lang=unsupported
> >> +            ;;
> >> +        esac
> >> +
> >>            # Disable jit if -enable-host-shared not specified
> >>            # but not if building for Mingw. All code in Windows
> >>            # is position independent code (PIC).
> >> diff --git a/configure.ac b/configure.ac
> >> index 1a19c07a27b..adb738ac346 100644
> >> --- a/configure.ac
> >> +++ b/configure.ac
> >> @@ -2036,6 +2036,28 @@ fi
> >>
> >>    AC_SUBST(PICFLAG)
> >>
> >> +# Rust requires -ldl and -lpthread if you are using an old glibc that
> >> does not include them by
> >> +# default, so we check for them here
> >> +
> >> +missing_rust_dynlibs=none
> >> +
> >> +AC_SEARCH_LIBS([dlopen], [dl])
> >> +AC_SEARCH_LIBS([pthread_create], [pthread])
> >> +
> >> +if test $ac_cv_search_dlopen = -ldl; then
> >> +    CRAB1_LIBS="$CRAB1_LIBS -ldl"
> >> +elif test $ac_cv_search_dlopen = no; then
> >> +    missing_rust_dynlibs="libdl"
> >> +fi
> >> +
> >> +if test $ac_cv_search_pthread_create = -lpthread; then
> >> +    CRAB1_LIBS="$CRAB1_LIBS -lpthread"
> >> +elif test $ac_cv_search_pthread_crate = no; then
> >> +    missing_rust_dynlibs="$missing_rust_dynlibs, libpthread"
> >> +fi
> >> +
> >> +AC_SUBST(CRAB1_LIBS, "$CRAB1_LIBS")
> >> +
> >>    # If we are building PIC/PIE host executables, and we are building
> >> dependent
> >>    # libs (e.g. GMP) in-tree those libs need to be configured to generate PIC
> >>    # code.
> >> @@ -2273,6 +2295,25 @@ if test -d ${srcdir}/gcc; then
> >>                ;;
> >>            esac
> >>
> >> +        # Disable Rust if we are missing some required C libraries for
> >> the Rust runtime.
> >> +        case ${add_this_lang}:${language}:${missing_rust_dynlibs} in
> >> +          *:rust:none)
> >> +            # Nothing to do - we're not missing any C libraries
> >> +            ;;
> >> +          yes:rust:*)
> >> +            AC_MSG_ERROR([some C libraries are required to build
> >> $language: $missing_rust_dynlibs])
> >> +            add_this_lang=unsupported
> >> +            ;;
> >> +          all:rust:*)
> >> +            AC_MSG_WARN([some C libraries are required to build
> >> $language: $missing_rust_dynlibs])
> >> +            add_this_lang=unsupported
> >> +            ;;
> >> +          *:rust:*)
> >> +            # Silently disable.
> >> +            add_this_lang=unsupported
> >> +            ;;
> >> +        esac
> >> +
> >>            # Disable jit if -enable-host-shared not specified
> >>            # but not if building for Mingw. All code in Windows
> >>            # is position independent code (PIC).
> >> diff --git a/gcc/rust/Make-lang.in b/gcc/rust/Make-lang.in
> >> index dd94c9b5eab..edcf2ee4c7b 100644
> >> --- a/gcc/rust/Make-lang.in
> >> +++ b/gcc/rust/Make-lang.in
> >> @@ -54,8 +54,6 @@ GCCRS_D_OBJS = \
> >>       rust/rustspec.o \
> >>       $(END)
> >>
> >> -LIBS += -ldl -lpthread
> >> -
> >>    gccrs$(exeext): $(GCCRS_D_OBJS) $(EXTRA_GCC_OBJS) libcommon-target.a
> >> $(LIBDEPS)
> >>          +$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
> >>            $(GCCRS_D_OBJS) $(EXTRA_GCC_OBJS) libcommon-target.a \
> >> @@ -234,7 +232,7 @@ crab1$(exeext): $(RUST_ALL_OBJS) attribs.o
> >> $(BACKEND) $(LIBDEPS) $(LIBPROC_MACRO
> >>          @$(call LINK_PROGRESS,$(INDEX.rust),start)
> >>          +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
> >>                $(RUST_ALL_OBJS) attribs.o $(BACKEND) \
> >> -             $(LIBS) $(LIBPROC_MACRO_INTERNAL) $(LIBFORMAT_PARSER)
> >> $(LIBFFI_POLONIUS) \
> >> +             $(LIBS) $(CRAB1_LIBS) $(LIBPROC_MACRO_INTERNAL)
> >> $(LIBFORMAT_PARSER) $(LIBFFI_POLONIUS) \
> >>                    $(BACKENDLIBS)
> >>          @$(call LINK_PROGRESS,$(INDEX.rust),end)
> >>
> >> @@ -496,4 +494,4 @@ rust/libffi_polonius.a: \
> >>          rust/checks/errors/borrowck/ffi-polonius/Cargo.toml \
> >>          $(wildcard $(srcdir)/rust/checks/errors/borrowck/ffi-polonius/src/*)
> >>          cargo build --manifest-path
> >> $(srcdir)/rust/checks/errors/borrowck/ffi-polonius/Cargo.toml --release
> >> --target-dir rust/ffi-polonius
> >> -       cp rust/ffi-polonius/release/libffi_polonius.a rust/libffi_polonius.a
> >> \ No newline at end of file
> >> +       cp rust/ffi-polonius/release/libffi_polonius.a rust/libffi_polonius.a
> >> --
> >> 2.42.0
> >>
>
> --
> Arthur Cohen <arthur.cohen@embecosm.com>
>
> Toolchain Engineer
>
> Embecosm GmbH
>
> Geschäftsführer: Jeremy Bennett
> Niederlassung: Nürnberg
> Handelsregister: HR-B 36368
> www.embecosm.de
>
> Fürther Str. 27
> 90429 Nürnberg
>
>
> Tel.: 091 - 128 707 040
> Fax: 091 - 128 707 077