except.c (choose_personality_routine): Export.

gcc/cp:
	* except.c (choose_personality_routine): Export.  Add
	explanatory comment.  Take an enum languages, not a boolean.
	(initialize_handler_parm): Adjust to match.
	* cp-tree.h: Prototype choose_personality_routine.
	* lex.c (handle_pragma_java_exceptions): New function.
	(init_cp_pragma): Register #pragma GCC java_exceptions.

gcc:
	* extend.texi: Document #pragma GCC java_exceptions.

libjava:
	* Makefile.am (libgcj_la_OBJECTS): Remove libsupc++convenience.la.
	* Makefile.in: Regenerate (by hand).
	* include/jvm.h: Add #pragma GCC java_exceptions at top of file.
	* doc/cni.sgml: Document #pragma GCC java_exceptions.

From-SVN: r42027

1 files changed, 36 insertions, 0 deletions

diff --git a/gcc/extend.texi b/gcc/extend.texi
index 5c52fcb..6b08843 100644
--- a/gcc/extend.texi
+++ b/gcc/extend.texi
@@ -3811,6 +3811,7 @@ Predefined Macros,cpp.info,The C Preprocessor}).
 * Bound member functions:: You can extract a function pointer to the
                         method denoted by a @samp{->*} or @samp{.*} expression.
 * C++ Attributes::      Variable, function, and type attributes for C++ only.
+* Java Exceptions::     Tweaking exception handling to work with Java.
 * Deprecated Features:: Things might disappear from g++.
 * Backwards Compatibility:: Compatibilities with earlier definitions of C++.
 @end menu
@@ -4380,6 +4381,41 @@ interface table mechanism, instead of regular virtual table dispatch.
 
 @end table
 
+@node Java Exceptions
+@section Java Exceptions
+
+The Java language uses a slightly different exception handling model
+from C++.  Normally, GNU C++ will automatically detect when you are
+writing C++ code that uses Java exceptions, and handle them
+appropriately.  However, if C++ code only needs to execute destructors
+when Java exceptions are thrown through it, GCC will guess incorrectly.
+Sample problematic code:
+
+@example
+  struct S @{ ~S(); @};
+  extern void bar();    // is implemented in Java and may throw exceptions
+  void foo()
+  @{
+    S s;
+    bar();
+  @}
+@end example
+
+@noindent
+The usual effect of an incorrect guess is a link failure, complaining of
+a missing routine called @samp{__gxx_personality_v0}.
+
+You can inform the compiler that Java exceptions are to be used in a
+translation unit, irrespective of what it might think, by writing
+@samp{@w{#pragma GCC java_exceptions}} at the head of the file.  This
+@samp{#pragma} must appear before any functions that throw or catch
+exceptions, or run destructors when exceptions are thrown through them.
+
+You cannot mix Java and C++ exceptions in the same translation unit.  It
+is believed to be safe to throw a C++ exception from one file through
+another file compiled for the for the Java exception model, or vice
+versa, but there may be bugs in this area.
+
 @node Deprecated Features
 @section Deprecated Features