Merge pull request #1126 from mesonbuild/sharedmodule

Support for shared modules

4 files changed, 208 insertions, 0 deletions

diff --git a/test cases/common/125 shared module/meson.build b/test cases/common/125 shared module/meson.build
new file mode 100644
index 000000000..ccb9c1a04
--- /dev/null
+++ b/test cases/common/125 shared module/meson.build
@@ -0,0 +1,16 @@
+project('shared module', 'c')
+
+if meson.backend().startswith('vs')
+  error('MESON_SKIP_TEST for some reason /FORCE does not work in the VS backend.')
+endif
+
+dl = meson.get_compiler('c').find_library('dl', required : false)
+l = shared_library('runtime', 'runtime.c')
+# Do NOT link the module with the runtime library. This
+# is a common approach for plugins that are only used
+# with dlopen. Any symbols are resolved dynamically
+# at runtime
+m = shared_module('mymodule', 'module.c')
+e = executable('prog', 'prog.c', link_with : l, dependencies : dl)
+test('import test', e, args : [m.full_path()])
+
diff --git a/test cases/common/125 shared module/module.c b/test cases/common/125 shared module/module.c
new file mode 100644
index 000000000..56078c565
--- /dev/null
+++ b/test cases/common/125 shared module/module.c
@@ -0,0 +1,71 @@
+#if defined _WIN32 || defined __CYGWIN__
+  #define DLL_PUBLIC __declspec(dllexport)
+#else
+  #if defined __GNUC__
+    #define DLL_PUBLIC __attribute__ ((visibility("default")))
+  #else
+    #pragma message ("Compiler does not support symbol visibility.")
+    #define DLL_PUBLIC
+  #endif
+#endif
+
+#ifdef _WIN32
+
+#include <stdio.h>
+#include <windows.h>
+#include <tlhelp32.h>
+
+typedef int (*fptr) (void);
+
+/* Unlike Linux and OS X, when a library is loaded, all the symbols aren't
+ * loaded into a single namespace. You must fetch the symbol by iterating over
+ * all loaded modules. Code for finding the function from any of the loaded
+ * modules is taken from gmodule.c in glib */
+fptr find_any_f (const char *name) {
+    fptr f;
+    HANDLE snapshot;
+    MODULEENTRY32 me32;
+
+    snapshot = CreateToolhelp32Snapshot (TH32CS_SNAPMODULE, 0);
+    if (snapshot == (HANDLE) -1) {
+        printf("Could not get snapshot\n");
+        return 0;
+    }
+
+    me32.dwSize = sizeof (me32);
+
+    f = NULL;
+    if (Module32First (snapshot, &me32)) {
+        do {
+            if ((f = (fptr) GetProcAddress (me32.hModule, name)) != NULL)
+                break;
+        } while (Module32Next (snapshot, &me32));
+    }
+
+    CloseHandle (snapshot);
+    return f;
+}
+
+int DLL_PUBLIC func() {
+    fptr f;
+
+    f = find_any_f ("func_from_language_runtime");
+    if (f != NULL)
+        return f();
+    printf ("Could not find function\n");
+    return 1;
+}
+
+#else
+/*
+ * Shared modules often have references to symbols that are not defined
+ * at link time, but which will be provided from deps of the executable that
+ * dlopens it. We need to make sure that this works, i.e. that we do
+ * not pass -Wl,--no-undefined when linking modules.
+ */
+int func_from_language_runtime();
+
+int DLL_PUBLIC func(void) {
+    return func_from_language_runtime();
+}
+#endif
diff --git a/test cases/common/125 shared module/prog.c b/test cases/common/125 shared module/prog.c
new file mode 100644
index 000000000..2b638409b
--- /dev/null
+++ b/test cases/common/125 shared module/prog.c
@@ -0,0 +1,102 @@
+
+#include <stdio.h>
+
+int func_from_language_runtime(void);
+typedef int (*fptr) (void);
+
+#ifdef _WIN32
+
+#include <windows.h>
+
+wchar_t*
+win32_get_last_error (void)
+{
+    wchar_t *msg = NULL;
+
+    FormatMessageW (FORMAT_MESSAGE_ALLOCATE_BUFFER
+                    | FORMAT_MESSAGE_IGNORE_INSERTS
+                    | FORMAT_MESSAGE_FROM_SYSTEM,
+                    NULL, GetLastError (), 0,
+                    (LPWSTR) &msg, 0, NULL);
+    return msg;
+}
+
+int
+main (int argc, char **argv)
+{
+    HINSTANCE handle;
+    fptr importedfunc;
+    int expected, actual;
+    int ret = 1;
+
+    handle = LoadLibraryA (argv[1]);
+    if (!handle) {
+        wchar_t *msg = win32_get_last_error ();
+        printf ("Could not open %s: %S\n", argv[1], msg);
+        goto nohandle;
+    }
+
+    importedfunc = (fptr) GetProcAddress (handle, "func");
+    if (importedfunc == NULL) {
+        wchar_t *msg = win32_get_last_error ();
+        printf ("Could not find 'func': %S\n", msg);
+        goto out;
+    }
+
+    actual = importedfunc ();
+    expected = func_from_language_runtime ();
+    if (actual != expected) {
+        printf ("Got %i instead of %i\n", actual, expected);
+        goto out;
+    }
+
+    ret = 0;
+out:
+    FreeLibrary (handle);
+nohandle:
+    return ret;
+}
+
+#else
+
+#include<dlfcn.h>
+#include<assert.h>
+
+int main(int argc, char **argv) {
+    void *dl;
+    fptr importedfunc;
+    int expected, actual;
+    char *error;
+    int ret = 1;
+
+    dlerror();
+    dl = dlopen(argv[1], RTLD_LAZY);
+    error = dlerror();
+    if(error) {
+        printf("Could not open %s: %s\n", argv[1], error);
+        goto nodl;
+    }
+
+    importedfunc = (fptr) dlsym(dl, "func");
+    if (importedfunc == NULL) {
+        printf ("Could not find 'func'\n");
+        goto out;
+    }
+
+    assert(importedfunc != func_from_language_runtime);
+
+    actual = (*importedfunc)();
+    expected = func_from_language_runtime ();
+    if (actual != expected) {
+        printf ("Got %i instead of %i\n", actual, expected);
+        goto out;
+    }
+
+    ret = 0;
+out:
+    dlclose(dl);
+nodl:
+    return ret;
+}
+
+#endif
diff --git a/test cases/common/125 shared module/runtime.c b/test cases/common/125 shared module/runtime.c
new file mode 100644
index 000000000..03bde8614
--- /dev/null
+++ b/test cases/common/125 shared module/runtime.c
@@ -0,0 +1,19 @@
+#if defined _WIN32 || defined __CYGWIN__
+  #define DLL_PUBLIC __declspec(dllexport)
+#else
+  #if defined __GNUC__
+    #define DLL_PUBLIC __attribute__ ((visibility("default")))
+  #else
+    #pragma message ("Compiler does not support symbol visibility.")
+    #define DLL_PUBLIC
+  #endif
+#endif
+
+/*
+ * This file pretends to be a language runtime that supports extension
+ * modules.
+ */
+
+int DLL_PUBLIC func_from_language_runtime(void) {
+    return 86;
+}