- add test6, which actually tries to open a shared lib with lt_dlopen.

For now I've been editing the Makefile directly and haven't updated
  the Makefile.in.  Once it works I'll transfer everything to Makefile.in
  and remove Makefile.

bochs-testing/plugin-test/test6-ltdlopen/Makefile

@@ -0,0 +1,43 @@
+top_builddir = ..
+srcdir = .
+
+
+CXX=g++
+CXXFLAGS=-g -O2
+LDFLAGS= -no-undefined
+LIBS=-L`pwd`/../ltdl -lltdl
+LIBTOOL=$(SHELL) $(top_builddir)/libtool
+RPATH=`pwd`/lib
+
+all: uselib libmodule1.la ### libmodule2.la
+
+uselib: libmain.la
+	$(LIBTOOL) $(CXX) $(LDFLAGS) -o uselib libmain.la $(LIBS)
+
+libmain.la: main.lo
+	$(LIBTOOL) $(CXX) $(LDFLAGS) -o libmain.la main.lo -rpath ${RPATH} $(LIBS)
+	mkdir -p lib bin
+	$(LIBTOOL) cp libmain.la ${RPATH}
+
+libmodule1.la: module1.lo libmain.la
+	$(LIBTOOL) $(CXX) $(LDFLAGS) -o libmodule1.la module1.lo -rpath ${RPATH} libmain.la
+	mkdir -p lib bin
+	$(LIBTOOL) cp libmodule1.la ${RPATH}
+
+libmodule2.la: module2.lo libmain.la
+	$(LIBTOOL) $(CXX) $(LDFLAGS) -o libmodule2.la module2.lo -rpath ${RPATH} libmain.la
+	mkdir -p lib bin
+	$(LIBTOOL) cp libmodule2.la ${RPATH}
+
+%.lo: %.cc
+	$(LIBTOOL) $(CXX) $(CXXFLAGS) -c $<
+
+test:
+	@echo "*** Running test in `pwd`"
+	-./uselib
+	@echo "*** Test done in `pwd`"
+
+clean:
+	-$(LIBTOOL) rm libmodule1.la module1.lo libmodule2.la module2.lo
+	rm -rf *.o *.lo *.la uselib.exe bin lib uselib uselib.exe
+	rm -rf .libs

bochs-testing/plugin-test/test6-ltdlopen/Makefile.in

@@ -0,0 +1,37 @@
+top_builddir = ..
+srcdir = @srcdir@
+VPATH = @srcdir@
+
+CXX=@CXX@
+CXXFLAGS=@CXXFLAGS@
+LDFLAGS=@LDFLAGS@ @LT_LDFLAGS@
+LIBTOOL=@LIBTOOL@
+RPATH=`pwd`/lib
+
+all: uselib
+
+uselib: uselib.cc libmodule1.la libmodule2.la
+	$(LIBTOOL) $(CXX) $(LDFLAGS) -o uselib $(srcdir)/uselib.cc libmodule1.la libmodule2.la
+
+libmodule1.la: module1.lo libmodule2.la
+	$(LIBTOOL) $(CXX) $(LDFLAGS) -o libmodule1.la module1.lo -rpath ${RPATH} libmodule2.la
+	mkdir -p lib bin
+	$(LIBTOOL) cp libmodule1.la ${RPATH}
+
+libmodule2.la: module2.lo
+	$(LIBTOOL) $(CXX) $(LDFLAGS) -o libmodule2.la module2.lo -rpath ${RPATH}
+	mkdir -p lib bin
+	$(LIBTOOL) cp libmodule2.la ${RPATH}
+
+%.lo: %.cc
+	$(LIBTOOL) $(CXX) $(CXXFLAGS) -c $<
+
+test:
+	@echo "*** Running test in `pwd`"
+	-./uselib
+	@echo "*** Test done in `pwd`"
+
+clean:
+	-$(LIBTOOL) rm libmodule1.la module1.lo libmodule2.la module2.lo
+	rm -rf *.o uselib.exe bin lib uselib uselib.exe
+	rm -rf .libs

bochs-testing/plugin-test/test6-ltdlopen/README

@@ -0,0 +1,27 @@
+test6-execsymbols2
+
+Try again to allow the module to reference symbols in the executable. 
+But this time, eliminate direct symbol references from the executable 
+to the module, so that the executable can be linked first.  I believe
+this will work ok for win32 and it's closer to how plugins need to work.
+
+What I think I learned from test5:
+> DLLs don't allow any symbols to be undefined at link time.  So you have to
+> choose the order of how to build things so that each link is complete.
+> For a DLL that's used as a shared library, it must be built and linked on
+> its own (without the program), with symbols exported.  This link must be
+> complete, so it can't depend on pieces from the program.  Then, the 
+> program can be linked with the DLL, with the program reading symbols from
+> the DLL.  It can't go both ways.
+> 
+> For a plugin environment, we want the plugin to be able to call functions
+> in the main code, without putting every single thing as a function pointer.
+> So the main executable should be built first, with appropriate symbols 
+> exported, and then the plugin can import those symbols.  The main 
+> executable will find symbols in the DLL using lt_dlopen() and lt_dlsym(),
+> which probably maps to LoadLibrary() and GetProcAddress().
+
+
+module1.lo: In function `module_init(void)':
+/home/bryce/bochs-testing/plugin-test/test6-execsymbols2/module1.cc:7: undefined reference to `import stub for register_module(char const *)'
+

bochs-testing/plugin-test/test6-ltdlopen/main.cc

@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <ltdl.h>
+#define MAIN_DLL_EXPORT
+#include "main.h"
+
+const char *version_string = "uselib-test6-1.0";
+
+int register_module (const char *name)
+{
+  printf ("register_module was called by module '%s'\n", name);
+  return 0;
+}
+
+int load_module (const char *fmt, const char *name)
+{
+  char buf[512];
+  sprintf (buf, fmt, name);
+  lt_dlhandle handle = lt_dlopen (buf);
+  printf ("handle is %p\n");
+  if (!handle) {
+    printf ("lt_dlopen error: %s\n", lt_dlerror ());
+	return -1;
+  }
+  modload_func func = (modload_func) lt_dlsym (handle, "_module_init");
+  printf ("module_init function is at %p\n", func);
+  if (func != NULL) {
+    printf ("Calling module_init\n");
+    (*func)();
+  } else {
+    printf ("lt_dlopen error: %s\n", lt_dlerror ());
+	return -1;
+  }
+  return 0;
+}
+
+int main (int argc, char **argv)
+{
+  printf ("start\n");
+  printf ("loading module1\n");
+  // try to load module1
+  if (load_module ("%s", argv[1]) < 0) {
+    printf ("load %s failed\n", argv[1]);
+  }
+  if (load_module ("%s.la", "module1") < 0) {
+    printf ("load module1 failed\n");
+  }
+  if (load_module ("%s.la", "module2") < 0) {
+    printf ("load module2 failed\n");
+  }
+  printf ("stop\n");
+  return 0;
+}

bochs-testing/plugin-test/test6-ltdlopen/main.h

@@ -0,0 +1,21 @@
+#if defined(WIN32) || defined(__CYGWIN__)
+#  ifdef MAIN_DLL_EXPORT
+#    ifdef DLL_EXPORT
+#      warning I will export DLL symbols for MODULE1
+#      define MAINAPI(type) __declspec(dllexport) type
+#    endif
+#  else
+#    warning I will import DLL symbols for MODULE1
+#    define MAINAPI(type) __declspec(dllimport) type
+#  endif
+#endif
+#ifndef MAINAPI
+#  warning No DLL import/export is needed
+#  define MAINAPI(type) type
+#endif
+
+typedef void (*modload_func)(void);
+
+MAINAPI(extern const char *) version_string;
+MAINAPI(extern int) register_module (const char *name);
+

bochs-testing/plugin-test/test6-ltdlopen/module1.cc

@@ -0,0 +1,18 @@
+#include <stdio.h>
+#include "main.h"
+
+extern "C" {
+  // prevent C++ name mangling
+  void module_init();
+};
+
+void module_init ()
+{
+  printf ("module1 init\n");
+  register_module ("module1");
+}
+
+int operate (int a, int b)
+{
+  return a + b;
+}

bochs-testing/plugin-test/test6-ltdlopen/module2.cc

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include "main.h"
+
+int n_operations = 0;
+
+void module_init ()
+{
+  printf ("module2 init\n");
+  register_module ("module2");
+}
+
+int operate (int a, int b)
+{
+  return a - b;
+}