c.opt: Add -fnothrow-opt.

gcc:
	* c.opt: Add -fnothrow-opt.
gcc/cp:
	* cp-tree.h (TYPE_NOEXCEPT_P): New macro.
	* except.c (begin_eh_spec_block): Use MUST_NOT_THROW_EXPR if
	TYPE_NOEXCEPT_P.
	(finish_eh_spec_block): Adjust.

From-SVN: r159450

gcc/ChangeLog

+2010-05-15  Jason Merrill  <jason@redhat.com>
+
+	* c.opt: Add -fnothrow-opt.
+
 2010-05-15  Jan Hubicka  <jh@suse.cz>
 
 	* ipa-prop.c (ipa_prop_read_section): Add sanity check that node is analyzed.

gcc/c.opt

@@ -689,6 +689,10 @@ C++ ObjC++
 fnonnull-objects
 C++ ObjC++
 
+fnothrow-opt
+C++ ObjC++ Optimization Var(flag_nothrow_opt)
+Treat a throw() exception specification as noexcept to improve code size
+
 ; Generate special '- .cxx_construct' and '- .cxx_destruct' methods
 ; to initialize any non-POD ivars in Objective-C++ classes.
 fobjc-call-cxx-cdtors

gcc/cp/ChangeLog

+2010-05-15  Jason Merrill  <jason@redhat.com>
+
+	* cp-tree.h (TYPE_NOEXCEPT_P): New macro.
+	* except.c (begin_eh_spec_block): Use MUST_NOT_THROW_EXPR if
+	TYPE_NOEXCEPT_P.
+	(finish_eh_spec_block): Adjust.
+
 2010-05-15  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/44148

gcc/cp/cp-tree.h

@@ -1741,6 +1741,12 @@ struct GTY(()) lang_type {
   (TYPE_RAISES_EXCEPTIONS (NODE) \
    && TREE_VALUE (TYPE_RAISES_EXCEPTIONS (NODE)) == NULL_TREE)
 
+/* For FUNCTION_TYPE or METHOD_TYPE, true if NODE is noexcept.  This is the
+   case for things declared noexcept(true) and, with -fnothrow-opt, for
+   throw() functions.  */
+#define TYPE_NOEXCEPT_P(NODE) \
+  (flag_nothrow_opt && TYPE_NOTHROW_P(NODE))
+
 /* The binding level associated with the namespace.  */
 #define NAMESPACE_LEVEL(NODE) \
   (LANG_DECL_NS_CHECK (NODE)->level)

gcc/cp/except.c

@@ -513,9 +513,18 @@ expand_end_catch_block (void)
 tree
 begin_eh_spec_block (void)
 {
-  tree r = build_stmt (input_location, EH_SPEC_BLOCK, NULL_TREE, NULL_TREE);
+  tree r;
+  /* A noexcept specification (or throw() with -fnothrow-opt) is a
+     MUST_NOT_THROW_EXPR.  */
+  if (TYPE_NOEXCEPT_P (TREE_TYPE (current_function_decl)))
+    {
+      r = build_stmt (input_location, MUST_NOT_THROW_EXPR, NULL_TREE);
+      TREE_SIDE_EFFECTS (r) = 1;
+    }
+  else
+    r = build_stmt (input_location, EH_SPEC_BLOCK, NULL_TREE, NULL_TREE);
   add_stmt (r);
-  EH_SPEC_STMTS (r) = push_stmt_list ();
+  TREE_OPERAND (r, 0) = push_stmt_list ();
   return r;
 }
 
@@ -524,7 +533,11 @@ finish_eh_spec_block (tree raw_raises, tree eh_spec_block)
 {
   tree raises;
 
-  EH_SPEC_STMTS (eh_spec_block) = pop_stmt_list (EH_SPEC_STMTS (eh_spec_block));
+  TREE_OPERAND (eh_spec_block, 0)
+    = pop_stmt_list (TREE_OPERAND (eh_spec_block, 0));
+
+  if (TREE_CODE (eh_spec_block) == MUST_NOT_THROW_EXPR)
+    return;
 
   /* Strip cv quals, etc, from the specification types.  */
   for (raises = NULL_TREE;

gcc/doc/invoke.texi

@@ -1929,6 +1929,15 @@ Disable built-in declarations of functions that are not mandated by
 ANSI/ISO C@.  These include @code{ffs}, @code{alloca}, @code{_exit},
 @code{index}, @code{bzero}, @code{conjf}, and other related functions.
 
+@item -fnothrow-opt
+@opindex fnothrow-opt
+Treat a @code{throw()} exception specification as though it were a
+@code{noexcept} specification to reduce or eliminate the text size
+overhead relative to a function with no exception specification.  The
+semantic effect is that an exception thrown out of a function with
+such an exception specification will result in a call to
+@code{terminate} rather than @code{unexpected}.
+
 @item -fno-operator-names
 @opindex fno-operator-names
 Do not treat the operator name keywords @code{and}, @code{bitand},

gcc/testsuite/ChangeLog

+2010-05-15  Jason Merrill  <jason@redhat.com>
+
+	* g++.dg/eh/spec10.C: New.
+	* g++.dg/eh/spec11.C: New.
+	* g++.old-deja/g++.mike/eh34.C: Remove dg-options.
+
 2010-05-15  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/44154

gcc/testsuite/g++.dg/eh/forced3.C

@@ -2,7 +2,7 @@
 // { dg-do run { xfail "ia64-hp-hpux11.*" } }
 
 // Test that forced unwinding calls std::unexpected going 
-// throw a nothrow function.
+// through a nothrow function.
 
 #include <unwind.h>
 #include <stdlib.h>

gcc/testsuite/g++.dg/eh/spec10.C

+// Make sure that we call terminate when a throw() spec is violated even
+// with -fnothrow-opt.  The function pointers are there to make sure that
+// the compiler doesn't get clever about optimizing the calls based on
+// knowledge about the called functions.
+
+// { dg-options "-fnothrow-opt" }
+// { dg-do run }
+
+#include <exception>
+#include <cstdlib>
+
+void my_terminate ()
+{
+  std::exit (0);
+}
+
+void g() { throw 1; }
+void (*p1)() = g;
+void f() throw() { p1(); }
+void (*p2)() = f;
+void h() { p2(); }
+
+int main()
+{
+  std::set_terminate (my_terminate);
+
+  try { h(); }
+  catch (int) { }
+
+  return 1;
+}

gcc/testsuite/g++.dg/eh/spec11.C

+// Make sure that we force an LSDA for a throw() spec with -fnothrow-opt so
+// that the personality routine will call terminate.
+
+// { dg-final { scan-assembler-not "_ZSt9terminatev" } }
+// { dg-final { scan-assembler-not "EHB" } }
+// { dg-final { scan-assembler "LSDA" } }
+
+// { dg-options "-fnothrow-opt" }
+
+void g();
+void f() throw() { g(); }

gcc/testsuite/g++.old-deja/g++.mike/eh34.C

 // { dg-do run { xfail sparc64-*-elf arm-*-pe } }
-// { dg-options "-fexceptions" }
 
 #include <exception>
 #include <stdlib.h>