Support implibs for executables on Windows

Add a boolean 'implib' kwarg to executable().  If true, it is permitted to
use the returned build target object in link_with:

On platforms where this makes sense (e.g. Windows), an implib is generated
for the executable and used when linking.  Otherwise, it has no effect.

(Rather than checking if it is a StaticLibrary or SharedLibary, BuildTarget
subclasses gain the is_linkable_target method to test if they can appear in
link_with:)

Also install any executable implib in a similar way to a shared library
implib, i.e. placing the implib in the appropriate place

Add tests of:
- a shared_module containing a reference to a symbol which is known (at link
time) to be provided by the executable
- trying to link with non-implib executables (should fail)
- installing the implib

(This last one needs a little enhancement of the installed file checking as
this is the first install test we have which needs to work with either
MSVC-style or GCC-style implib filenames)

9 files changed, 130 insertions, 0 deletions

diff --git a/test cases/common/154 shared module resolving symbol in executable/meson.build b/test cases/common/154 shared module resolving symbol in executable/meson.build
new file mode 100644
index 0000000..06c9902
--- /dev/null
+++ b/test cases/common/154 shared module resolving symbol in executable/meson.build
@@ -0,0 +1,24 @@
+project('shared module resolving symbol in executable', 'c')
+
+# The shared module contains a reference to the symbol 'func_from_executable',
+# which is always provided by the executable which loads it.  This symbol can be
+# resolved at run-time by an ELF loader.  But when building PE/COFF objects, all
+# symbols must be resolved at link-time, so an implib is generated for the
+# executable, and the shared module linked with it.
+#
+# See testcase 125 for an example of the more complex portability gymnastics
+# required if we do not know (at link-time) what provides the symbol.
+
+link_flags = []
+if host_machine.system() != 'windows'
+  # Needed to export dynamic symbols from the executable
+  link_flags += ['-rdynamic']
+  # Need to add this manually because Meson won't add it automatically because
+  # it doesn't know that we are loading a module from the build directory.
+  link_flags += ['-Wl,-rpath,' + meson.current_build_dir()]
+endif
+
+dl = meson.get_compiler('c').find_library('dl', required: false)
+e = executable('prog', 'prog.c', dependencies: dl, implib: true, link_args: link_flags)
+m = shared_module('module', 'module.c', link_with: e)
+test('test', e, args: m)
diff --git a/test cases/common/154 shared module resolving symbol in executable/module.c b/test cases/common/154 shared module resolving symbol in executable/module.c
new file mode 100644
index 0000000..64374d5
--- /dev/null
+++ b/test cases/common/154 shared module resolving symbol in executable/module.c
@@ -0,0 +1,16 @@
+#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
+
+extern int func_from_executable(void);
+
+int DLL_PUBLIC func(void) {
+   return func_from_executable();
+}
diff --git a/test cases/common/154 shared module resolving symbol in executable/prog.c b/test cases/common/154 shared module resolving symbol in executable/prog.c
new file mode 100644
index 0000000..746c192
--- /dev/null
+++ b/test cases/common/154 shared module resolving symbol in executable/prog.c
@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <assert.h>
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <dlfcn.h>
+#endif
+
+#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
+
+typedef int (*fptr) (void);
+
+int DLL_PUBLIC
+func_from_executable(void)
+{
+  return 42;
+}
+
+int
+main (int argc, char **argv)
+{
+  int expected, actual;
+  fptr importedfunc;
+
+#ifdef _WIN32
+  HMODULE h = LoadLibraryA(argv[1]);
+#else
+  void *h = dlopen(argv[1], RTLD_NOW);
+#endif
+  assert(h != NULL);
+
+#ifdef _WIN32
+  importedfunc = (fptr) GetProcAddress (h, "func");
+#else
+  importedfunc = (fptr) dlsym(h, "func");
+#endif
+  assert(importedfunc != NULL);
+  assert(importedfunc != func_from_executable);
+
+  actual = (*importedfunc)();
+  expected = func_from_executable();
+  assert(actual == expected);
+
+#ifdef _WIN32
+  FreeLibrary(h);
+#else
+  dlclose(h);
+#endif
+
+  return 0;
+}
diff --git a/test cases/failing/57 link with executable/meson.build b/test cases/failing/57 link with executable/meson.build
new file mode 100644
index 0000000..186b3e5
--- /dev/null
+++ b/test cases/failing/57 link with executable/meson.build
@@ -0,0 +1,4 @@
+project('link with exe', 'c')
+
+e = executable('prog', 'prog.c')
+m = shared_module('module', 'module.c', link_with: e)
diff --git a/test cases/failing/57 link with executable/module.c b/test cases/failing/57 link with executable/module.c
new file mode 100644
index 0000000..dc0124a
--- /dev/null
+++ b/test cases/failing/57 link with executable/module.c
@@ -0,0 +1,4 @@
+
+int func(void) {
+   return 42;
+}
diff --git a/test cases/failing/57 link with executable/prog.c b/test cases/failing/57 link with executable/prog.c
new file mode 100644
index 0000000..f3836d7
--- /dev/null
+++ b/test cases/failing/57 link with executable/prog.c
@@ -0,0 +1,5 @@
+int
+main (int argc, char **argv)
+{
+  return 0;
+}
diff --git a/test cases/windows/12 exe implib/installed_files.txt b/test cases/windows/12 exe implib/installed_files.txt
new file mode 100644
index 0000000..d0ea8f6
--- /dev/null
+++ b/test cases/windows/12 exe implib/installed_files.txt
@@ -0,0 +1,4 @@
+usr/bin/prog.exe
+usr/bin/prog.pdb
+?gcc:usr/lib/libprog.exe.a
+?msvc:usr/lib/prog.lib
diff --git a/test cases/windows/12 exe implib/meson.build b/test cases/windows/12 exe implib/meson.build
new file mode 100644
index 0000000..2393e79
--- /dev/null
+++ b/test cases/windows/12 exe implib/meson.build
@@ -0,0 +1,7 @@
+project('wintest', 'c')
+
+# Test that we can produce an implib for an executable on Windows, and that it
+# is installed along with the executable
+
+prog = executable('prog', 'prog.c', install: true, implib: true)
+test('wintest', prog)
diff --git a/test cases/windows/12 exe implib/prog.c b/test cases/windows/12 exe implib/prog.c
new file mode 100644
index 0000000..6d5a9f5
--- /dev/null
+++ b/test cases/windows/12 exe implib/prog.c
@@ -0,0 +1,6 @@
+#include <windows.h>
+
+int  __declspec(dllexport)
+main(int argc, char **argv) {
+    return 0;
+}