FYI: fix some java-related crashes

[Tom Tromey <tromey at redhat dot com>]

I'm checking this in.

I was debugging a gcj-compiled program the other day and had gdb crash
while re-running it.

The problem occurs in create_longjmp_master_breakpoint:

      if (!gdbarch_get_longjmp_target_p (get_objfile_arch (objfile)))
	continue;

Here, get_objfile_arch returns NULL, because the phony objfile made by
jv-lang.c doesn't have an arch.

I considered fixing all the users of get_objfile_arch, but there are
many, and it seemed strange to have an arch-less objfile anyhow.

This patch also arranges to clean up the phony objfile and some other
internal caches whenever appropriate.

Built and regtested on x86-64 (compile farm).
I also ran the new gdb under gdb, on my java program, and watched the
caches get cleared when I re-ran the inferior.

Tom

2010-03-19  Tom Tromey  <tromey@redhat.com>

	* jv-lang.c (jv_dynamics_objfile_data_key)
	(jv_type_objfile_data_key): New globals.
	(class_symtab): Move earlier.
	(jv_per_objfile_free): New function.
	(get_dynamics_objfile): Call set_objfile_data.  Add 'gdbarch'
	parameter.
	Remove ancient #if 1.
	(add_class_symbol): Remove redundant declaration.
	(java_lookup_class): Use alloc_type, not alloc_type_arch.
	(java_link_class_type): Mark as static.  Update.
	(jv_clear_object_type): New function.
	(set_java_object_type): Likewise.
	(get_java_object_type): Use set_java_object_type.
	(is_object_type): Likewise.
	(_initialize_java_language): Register new objfile keys.
	(get_java_class_symtab): Add 'gdbarch' parameter.
	(add_class_symtab_symbol): Update.
	(type_from_class): Update.

diff --git a/gdb/jv-lang.c b/gdb/jv-lang.c
index 24b6673..6c449ef 100644
--- a/gdb/jv-lang.c
+++ b/gdb/jv-lang.c
@@ -46,7 +46,7 @@ extern void _initialize_java_language (void);
 static int java_demangled_signature_length (char *);
 static void java_demangled_signature_copy (char *, char *);
 
-static struct symtab *get_java_class_symtab (void);
+static struct symtab *get_java_class_symtab (struct gdbarch *gdbarch);
 static char *get_java_utf8_name (struct obstack *obstack, struct value *name);
 static int java_class_is_primitive (struct value *clas);
 static struct value *java_value_string (char *ptr, int len);
@@ -56,15 +56,35 @@ static void java_emit_char (int c, struct type *type,
 
 static char *java_class_name_from_physname (const char *physname);
 
+static const struct objfile_data *jv_dynamics_objfile_data_key;
+static const struct objfile_data *jv_type_objfile_data_key;
+
 /* This objfile contains symtabs that have been dynamically created
    to record dynamically loaded Java classes and dynamically
    compiled java methods. */
 
 static struct objfile *dynamics_objfile = NULL;
 
+/* symtab contains classes read from the inferior. */
+
+static struct symtab *class_symtab = NULL;
+
 static struct type *java_link_class_type (struct gdbarch *,
 					  struct type *, struct value *);
 
+/* A function called when the dynamics_objfile is freed.  We use this
+   to clean up some internal state.  */
+static void
+jv_per_objfile_free (struct objfile *objfile, void *ignore)
+{
+  gdb_assert (objfile == dynamics_objfile);
+  /* Clean up all our cached state.  These objects are all allocated
+     in the dynamics_objfile, so we don't need to actually free
+     anything.  */
+  dynamics_objfile = NULL;
+  class_symtab = NULL;
+}
+
 /* FIXME: carlton/2003-02-04: This is the main or only caller of
    allocate_objfile with first argument NULL; as a result, this code
    breaks every so often.  Somebody should write a test case that
@@ -72,28 +92,32 @@ static struct type *java_link_class_type (struct gdbarch *,
    dynamic library) after this code has been called.  */
 
 static struct objfile *
-get_dynamics_objfile (void)
+get_dynamics_objfile (struct gdbarch *gdbarch)
 {
   if (dynamics_objfile == NULL)
     {
-      dynamics_objfile = allocate_objfile (NULL, 0);
+      /* Mark it as shared so that it is cleared when the inferior is
+	 re-run.  */
+      dynamics_objfile = allocate_objfile (NULL, OBJF_SHARED);
+      dynamics_objfile->gdbarch = gdbarch;
+      /* We don't have any data to store, but this lets us get a
+	 notification when the objfile is destroyed.  Since we have to
+	 store a non-NULL value, we just pick something arbitrary and
+	 safe.  */
+      set_objfile_data (dynamics_objfile, jv_dynamics_objfile_data_key,
+			&dynamics_objfile);
     }
   return dynamics_objfile;
 }
 
-#if 1
-/* symtab contains classes read from the inferior. */
-
-static struct symtab *class_symtab = NULL;
-
 static void free_class_block (struct symtab *symtab);
 
 static struct symtab *
-get_java_class_symtab (void)
+get_java_class_symtab (struct gdbarch *gdbarch)
 {
   if (class_symtab == NULL)
     {
-      struct objfile *objfile = get_dynamics_objfile ();
+      struct objfile *objfile = get_dynamics_objfile (gdbarch);
       struct blockvector *bv;
       struct block *bl;
       class_symtab = allocate_symtab ("<java-classes>", objfile);
@@ -122,13 +146,12 @@ get_java_class_symtab (void)
 static void
 add_class_symtab_symbol (struct symbol *sym)
 {
-  struct symtab *symtab = get_java_class_symtab ();
+  struct symtab *symtab
+    = get_java_class_symtab (get_objfile_arch (SYMBOL_SYMTAB (sym)->objfile));
   struct blockvector *bv = BLOCKVECTOR (symtab);
   dict_add_symbol (BLOCK_DICT (BLOCKVECTOR_BLOCK (bv, GLOBAL_BLOCK)), sym);
 }
 
-static struct symbol *add_class_symbol (struct type *type, CORE_ADDR addr);
-
 static struct symbol *
 add_class_symbol (struct type *type, CORE_ADDR addr)
 {
@@ -155,7 +178,6 @@ free_class_block (struct symtab *symtab)
 
   dict_free (BLOCK_DICT (bl));
 }
-#endif
 
 struct type *
 java_lookup_class (char *name)
@@ -269,7 +291,7 @@ type_from_class (struct gdbarch *gdbarch, struct value *clas)
     }
 #endif
 
-  objfile = get_dynamics_objfile ();
+  objfile = get_dynamics_objfile (gdbarch);
   if (java_class_is_primitive (clas))
     {
       struct value *sig;
@@ -293,10 +315,7 @@ type_from_class (struct gdbarch *gdbarch, struct value *clas)
   if (type != NULL)
     return type;
 
-  /* Do not use the "fake" dynamics objfile to own dynamically generated
-     types, as it does not provide an architecture, and it would not help
-     manage the lifetime of these types anyway.  */
-  type = alloc_type_arch (gdbarch);
+  type = alloc_type (objfile);
   TYPE_CODE (type) = TYPE_CODE_STRUCT;
   INIT_CPLUS_SPECIFIC (type);
 
@@ -325,7 +344,7 @@ type_from_class (struct gdbarch *gdbarch, struct value *clas)
 
 /* Fill in class TYPE with data from the CLAS value. */
 
-struct type *
+static struct type *
 java_link_class_type (struct gdbarch *gdbarch,
 		      struct type *type, struct value *clas)
 {
@@ -341,7 +360,7 @@ java_link_class_type (struct gdbarch *gdbarch,
   struct value *method = NULL;
   struct value *field = NULL;
   int i, j;
-  struct objfile *objfile = get_dynamics_objfile ();
+  struct objfile *objfile = get_dynamics_objfile (gdbarch);
   struct type *tsuper;
 
   gdb_assert (name != NULL);
@@ -570,6 +589,28 @@ java_link_class_type (struct gdbarch *gdbarch,
 
 static struct type *java_object_type;
 
+/* A free function that is attached to the objfile defining
+   java_object_type.  This is used to clear the cached type whenever
+   its owning objfile is destroyed.  */
+static void
+jv_clear_object_type (struct objfile *objfile, void *ignore)
+{
+  java_object_type = NULL;
+}
+
+static void
+set_java_object_type (struct type *type)
+{
+  struct objfile *owner;
+
+  gdb_assert (java_object_type == NULL);
+
+  owner = TYPE_OBJFILE (type);
+  if (owner)
+    set_objfile_data (owner, jv_type_objfile_data_key, &java_object_type);
+  java_object_type = type;
+}
+
 struct type *
 get_java_object_type (void)
 {
@@ -579,7 +620,7 @@ get_java_object_type (void)
       sym = lookup_symbol ("java.lang.Object", NULL, STRUCT_DOMAIN, NULL);
       if (sym == NULL)
 	error (_("cannot find java.lang.Object"));
-      java_object_type = SYMBOL_TYPE (sym);
+      set_java_object_type (SYMBOL_TYPE (sym));
     }
   return java_object_type;
 }
@@ -613,7 +654,7 @@ is_object_type (struct type *type)
       if (name != NULL && strcmp (name, "vtable") == 0)
 	{
 	  if (java_object_type == NULL)
-	    java_object_type = type;
+	    set_java_object_type (type);
 	  return 1;
 	}
     }
@@ -1203,6 +1244,11 @@ builtin_java_type (struct gdbarch *gdbarch)
 void
 _initialize_java_language (void)
 {
+  jv_dynamics_objfile_data_key
+    = register_objfile_data_with_cleanup (NULL, jv_per_objfile_free);
+  jv_type_objfile_data_key
+    = register_objfile_data_with_cleanup (NULL, jv_clear_object_type);
+
   java_type_data = gdbarch_data_register_post_init (build_java_types);
 
   add_language (&java_language_defn);