RFC: libjvm.so

[Thomas Fitzsimmons <fitzsim at redhat dot com>]

Hi,

This patch introduces a new library, libjvm.so, that implements the JNI 
Invocation API.  Binaries that want to embed a VM, such as the GNU Classpath 
tool wrappers, can link to this library.

This patch adds the necessary build logic, moves the symbols to a separate file 
and exports other symbols that libjvm.so needs from libgcj.so.  In order to make 
our libjvm.so binary compatible with other implementations, we'll need a 
libjvm.so with a SONAME of "libjvm.so" instead of the current "libjvm.so.7". 
But I'll do that as a separate patch since Bryce is working on a solution to the 
same problem for libgcj-bc.so.

Tom

2006-06-19  Thomas Fitzsimmons  <fitzsim@redhat.com>

	* Makefile.am (AM_CXXFLAGS): Define GCJ_VERSIONED_LIBDIR to
	"$(dbexecdir)".
	Build libjvm.la.
	* Makefile.in: Regenerate.
	* jni.cc (the_vm): Rename and export as ...
	(_Jv_the_vm): New exported symbol.
	(_Jv_JNI_AttachCurrentThread): Export.
	(_Jv_JNI_DestroyJavaVM): Replace the_vm references with _Jv_the_vm
	references.
	(_Jv_GetJavaVM): Likewise.
	(JNI_GetDefaultJavaVMInitArgs, JNI_CreateJavaVM,
	JNI_GetCreatedJavaVMs): Move to ...
	* jni-libjvm.cc: New file.

Index: jni-libjvm.cc
===================================================================
--- jni-libjvm.cc	(revision 0)
+++ jni-libjvm.cc	(revision 0)
@@ -0,0 +1,89 @@
+// jni-libjvm.cc - an implementation of the JNI invocation API.
+
+/* Copyright (C) 2006  Free Software Foundation
+
+   This file is part of libgcj.
+
+This software is copyrighted work licensed under the terms of the
+Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
+details.  */
+
+#include <gcj/cni.h>
+#include <gcj/javaprims.h>
+#include <java-assert.h>
+#include <jvm.h>
+#include <jni.h>
+
+using namespace gcj;
+
+// Forward declarations.
+extern struct JNIInvokeInterface _Jv_JNI_InvokeFunctions;
+extern jint JNICALL _Jv_JNI_AttachCurrentThread (JavaVM *vm,
+                                                 void **penv, void *args);
+extern JavaVM *_Jv_the_vm;
+
+jint JNICALL
+JNI_GetDefaultJavaVMInitArgs (void *args)
+{
+  jint version = * (jint *) args;
+  // Here we only support 1.2 and 1.4.
+  if (version != JNI_VERSION_1_2 && version != JNI_VERSION_1_4)
+    return JNI_EVERSION;
+
+  JavaVMInitArgs *ia = reinterpret_cast<JavaVMInitArgs *> (args);
+  ia->version = JNI_VERSION_1_4;
+  ia->nOptions = 0;
+  ia->options = NULL;
+  ia->ignoreUnrecognized = true;
+
+  return 0;
+}
+
+jint JNICALL
+JNI_CreateJavaVM (JavaVM **vm, void **penv, void *args)
+{
+  JvAssert (! _Jv_the_vm);
+
+  jint version = * (jint *) args;
+  // We only support 1.2 and 1.4.
+  if (version != JNI_VERSION_1_2 && version != JNI_VERSION_1_4)
+    return JNI_EVERSION;
+
+  JvVMInitArgs* vm_args = reinterpret_cast<JvVMInitArgs *> (args);
+
+  jint result = _Jv_CreateJavaVM (vm_args);
+  if (result)
+    return result;
+
+  // FIXME: synchronize
+  JavaVM *nvm = (JavaVM *) _Jv_MallocUnchecked (sizeof (JavaVM));
+  if (nvm == NULL)
+    return JNI_ERR;
+  nvm->functions = &_Jv_JNI_InvokeFunctions;
+
+  jint r =_Jv_JNI_AttachCurrentThread (nvm, penv, NULL);
+  if (r < 0)
+    return r;
+
+  _Jv_the_vm = nvm;
+  *vm = _Jv_the_vm;
+
+  return 0;
+}
+
+jint JNICALL
+JNI_GetCreatedJavaVMs (JavaVM **vm_buffer, jsize buf_len, jsize *n_vms)
+{
+  if (buf_len <= 0)
+    return JNI_ERR;
+
+  // We only support a single VM.
+  if (_Jv_the_vm != NULL)
+    {
+      vm_buffer[0] = _Jv_the_vm;
+      *n_vms = 1;
+    }
+  else
+    *n_vms = 0;
+  return 0;
+}
Index: jni.cc
===================================================================
--- jni.cc	(revision 114777)
+++ jni.cc	(working copy)
@@ -107,7 +107,7 @@
 static java::util::IdentityHashMap *global_ref_table;
 
 // The only VM.
-static JavaVM *the_vm;
+JavaVM *_Jv_the_vm;
 
 #ifdef ENABLE_JVMPI
 // The only JVMPI interface description.
@@ -2408,7 +2408,7 @@
 }
 
 // This is the one actually used by JNI.
-static jint JNICALL
+jint JNICALL
 _Jv_JNI_AttachCurrentThread (JavaVM *vm, void **penv, void *args)
 {
   return _Jv_JNI_AttachCurrentThread (vm, NULL, penv, args, false);
@@ -2424,7 +2424,7 @@
 static jint JNICALL
 _Jv_JNI_DestroyJavaVM (JavaVM *vm)
 {
-  JvAssert (the_vm && vm == the_vm);
+  JvAssert (_Jv_the_vm && vm == _Jv_the_vm);
 
   union
   {
@@ -2496,82 +2496,16 @@
   return 0;
 }
 
-jint JNICALL
-JNI_GetDefaultJavaVMInitArgs (void *args)
-{
-  jint version = * (jint *) args;
-  // Here we only support 1.2 and 1.4.
-  if (version != JNI_VERSION_1_2 && version != JNI_VERSION_1_4)
-    return JNI_EVERSION;
-
-  JavaVMInitArgs *ia = reinterpret_cast<JavaVMInitArgs *> (args);
-  ia->version = JNI_VERSION_1_4;
-  ia->nOptions = 0;
-  ia->options = NULL;
-  ia->ignoreUnrecognized = true;
-
-  return 0;
-}
-
-jint JNICALL
-JNI_CreateJavaVM (JavaVM **vm, void **penv, void *args)
-{
-  JvAssert (! the_vm);
-
-  jint version = * (jint *) args;
-  // We only support 1.2 and 1.4.
-  if (version != JNI_VERSION_1_2 && version != JNI_VERSION_1_4)
-    return JNI_EVERSION;
-
-  JvVMInitArgs* vm_args = reinterpret_cast<JvVMInitArgs *> (args);
-
-  jint result = _Jv_CreateJavaVM (vm_args);
-  if (result)
-    return result;
-
-  // FIXME: synchronize
-  JavaVM *nvm = (JavaVM *) _Jv_MallocUnchecked (sizeof (JavaVM));
-  if (nvm == NULL)
-    return JNI_ERR;
-  nvm->functions = &_Jv_JNI_InvokeFunctions;
-
-  jint r =_Jv_JNI_AttachCurrentThread (nvm, penv, NULL);
-  if (r < 0)
-    return r;
-
-  the_vm = nvm;
-  *vm = the_vm;
-
-  return 0;
-}
-
-jint JNICALL
-JNI_GetCreatedJavaVMs (JavaVM **vm_buffer, jsize buf_len, jsize *n_vms)
-{
-  if (buf_len <= 0)
-    return JNI_ERR;
-
-  // We only support a single VM.
-  if (the_vm != NULL)
-    {
-      vm_buffer[0] = the_vm;
-      *n_vms = 1;
-    }
-  else
-    *n_vms = 0;
-  return 0;
-}
-
 JavaVM *
 _Jv_GetJavaVM ()
 {
   // FIXME: synchronize
-  if (! the_vm)
+  if (! _Jv_the_vm)
     {
       JavaVM *nvm = (JavaVM *) _Jv_MallocUnchecked (sizeof (JavaVM));
       if (nvm != NULL)
 	nvm->functions = &_Jv_JNI_InvokeFunctions;
-      the_vm = nvm;
+      _Jv_the_vm = nvm;
     }
 
   // If this is a Java thread, we want to make sure it has an
@@ -2579,10 +2513,10 @@
   if (_Jv_ThreadCurrent () != NULL)
     {
       void *ignore;
-      _Jv_JNI_AttachCurrentThread (the_vm, &ignore, NULL);
+      _Jv_JNI_AttachCurrentThread (_Jv_the_vm, &ignore, NULL);
     }
 
-  return the_vm;
+  return _Jv_the_vm;
 }
 
 static jint JNICALL
Index: Makefile.am
===================================================================
--- Makefile.am	(revision 114777)
+++ Makefile.am	(working copy)
@@ -40,6 +40,8 @@
 toolexeclib_LTLIBRARIES += lib-gnu-awt-xlib.la
 endif
 
+dbexec_LTLIBRARIES = libjvm.la
+
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = libgcj.pc
 
@@ -122,7 +124,7 @@
         -DBOOT_CLASS_PATH="\"$(BOOT_CLASS_PATH_DIR)\"" \
 	-DJAVA_EXT_DIRS="\"$(jardir)/ext\"" \
 	-DGCJ_ENDORSED_DIRS="\"$(jardir)/gcj-endorsed\"" \
-	-DGCJ_VERSIONED_LIBDIR="\"$(libdir)/gcj-$(gcc_version)\"" \
+	-DGCJ_VERSIONED_LIBDIR="\"$(dbexecdir)\"" \
 	-DPATH_SEPARATOR="\"$(CLASSPATH_SEPARATOR)\"" \
 	-DLIBGCJ_DEFAULT_DATABASE="\"$(dbexecdir)/$(db_name)\"" \
 	-DLIBGCJ_DEFAULT_DATABASE_PATH_TAIL="\"$(db_pathtail)\"" \
@@ -232,6 +234,14 @@
 	$(LIBLTDL) $(libgcj_la_LIBADD)
 libgcj_la_LINK = $(LIBLINK)
 
+## libjvm.so
+libjvm_la_SOURCES = jni-libjvm.cc
+libjvm_la_DEPENDENCIES = libgcj.la libgcj.spec
+## See jv_convert_LDADD.
+libjvm_la_LIBADD = -L$(here)/.libs libgcj.la
+## The mysterious backslash in the grep pattern is consumed by make.
+libjvm_la_LDFLAGS = -rpath $(toolexeclibdir) \
+        -version-info `grep -v '^\#' $(srcdir)/libtool-version` $(LIBGCJ_LD_SYMBOLIC)
 
 ## The .db file.  This rule is only used for native builds, so it is
 ## safe to invoke gcj-dbtool.
@@ -887,6 +897,7 @@
 
 $(libgcj_la_OBJECTS) $(gcj_dbtool_OBJECTS) $(xlib_nat_files): headers.stamp
 $(libgij_la_OBJECTS): headers.stamp
+$(libjvm_la_OBJECTS): headers.stamp
 
 ## ################################################################