[GHC] #3807: Test for correct shared library generation

[GHC]

#3807: Test for correct shared library generation
---------------------------------+------------------------------------------
    Reporter:  asuffield         |       Owner:              
        Type:  bug               |      Status:  new         
    Priority:  normal            |   Component:  Test Suite  
     Version:  6.12.1            |    Keywords:              
          Os:  Unknown/Multiple  |    Testcase:              
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown
---------------------------------+------------------------------------------
 There doesn't seem to be a test that verifies shared libraries are
 correctly created. It's not immediately obvious how to get the test suite
 driver to run this sort of thing, so I don't have a full patch for it, but
 this illustrates how it should work on ELF and ELF-like platforms:

 {{{
 asuffield at cyclone:~/work/ghc-test$ cat TestExport.hs
 module Test where
 asuffield at cyclone:~/work/ghc-test$ cat test-export.c
 #include <HsFFI.h>

 extern void __stginit_Test(void);

 void
 test_init (void)
 {
   static char *argv[] = { "test.so", 0 }, **argv_ = argv;
   static int argc = 1;

   hs_init (&argc, &argv_);
   hs_add_root (__stginit_Test);
 }

 void
 test_exit (void)
 {
   hs_exit ();
 }
 asuffield at cyclone:~/work/ghc-test$ cat testload.c
 #include <dlfcn.h>
 #include <stdio.h>

 int main(void) {
   void *dh = dlopen("./test.so", RTLD_NOW | RTLD_GLOBAL);
   if (!dh) {
     printf("%s\n", dlerror());
     return 1;
   }

   void (*test_init)(void) = dlsym(dh, "test_init");
   void (*test_exit)(void) = dlsym(dh, "test_exit");

   test_init();
   test_exit();

   return 0;
 }
 asuffield at cyclone:~/work/ghc-test$ ghc --make -dynamic -fPIC -shared
 TestExport.hs test-export.c -o test.so
 [1 of 1] Compiling Test             ( TestExport.hs, TestExport.o )
 Linking test.so ...
 asuffield at cyclone:~/work/ghc-test$ gcc -o testload testload.c -ldl
 asuffield at cyclone:~/work/ghc-test$ ./testload
 /usr/lib/ghc-6.12.0.20091126/ghc-prim-0.2.0.0/libHSghc-
 prim-0.2.0.0-ghc6.12.0.20091126.so: undefined symbol: stg_newByteArrayzh
 }}}

 You'll note that the test failed here, in a way which illustrates why the
 current FFI tests don't properly exercise this: the shared library
 references symbols from libHSrts*.so, but does not link to it. If testload
 had been compiled with ghc instead of gcc (like all the current FFI tests)
 then the binary itself would have picked up that library and caused a
 false pass; doing it this way verifies that shared libraries can be loaded
 into foreign programs. The use of dlopen here is simply to force strict
 loading of the shared library in a reasonably portable manner, since
 linking directly to it is lazily evaluated on many platforms.

 Incidentally, I suspect this will fail on current versions.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3807>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler