configure.in, configure: enable dwarf2-exception-style exception handling on IA-64.

	* configure.in, configure: enable dwarf2-exception-style
	exception handling on IA-64.
	* include/dwarf2-signal.h (MAKE_THROW_FRAME): Add for IA-64.
	(INIT_SEGV, INIT_FPE): Use __libc_sigaction instead of syscall.
	Add FIXME comment.

From-SVN: r51367

1 files changed, 30 insertions, 2 deletions

diff --git a/libjava/include/dwarf2-signal.h b/libjava/include/dwarf2-signal.h
index 3a662ae..f1572d3 100644
--- a/libjava/include/dwarf2-signal.h
+++ b/libjava/include/dwarf2-signal.h
@@ -41,7 +41,25 @@ do									\
   _sc->sc_pc += 4;							\
 }									\
 while (0)
+
+#elif defined(__ia64__)
+
+#define MAKE_THROW_FRAME(_exception)					\
+do									\
+{									\
+  /* IA-64 either leaves PC pointing at a faulting instruction or the	\
+   following instruction, depending on the signal.  SEGV always does	\
+   the former, so we adjust the saved PC to point to the following	\
+   instruction; this is what the handler in libgcc expects.  */		\
+  /* Note that we are lying to the unwinder here, which expects the	\
+   faulting pc, not pc+1.  But we claim the unwind information can't	\
+   be changed by such a ld or st instruction, so it doesn't matter. */	\
+  struct sigcontext *_sc = (struct sigcontext *)_p;			\
+  _sc->sc_ip++;								\
+}									\
+while (0)
 #else
+#error
 #define MAKE_THROW_FRAME(_exception)		\
 do						\
 {						\
@@ -50,6 +68,16 @@ do						\
 while (0)
 #endif
 
+// FIXME: We shouldn't be using libc_sigaction here, since it should
+// be glibc private.  But using syscall here would mean translating to
+// the kernel's struct sigaction and argument sequence, which we
+// shouldn't either.  The right solution is to call sigaction and to
+// make sure that we can unwind correctly through the pthread signal
+// wrapper.
+extern "C" int __libc_sigaction (int __sig, 
+		      __const struct sigaction *__restrict __act,
+                      struct sigaction *__restrict __oact) throw ();
+
 #define INIT_SEGV						\
 do								\
   {								\
@@ -58,7 +86,7 @@ do								\
     act.sa_sigaction = _Jv_catch_segv;      			\
     sigemptyset (&act.sa_mask);					\
     act.sa_flags = SA_SIGINFO;	       				\
-    syscall (SYS_sigaction, SIGSEGV, &act, NULL);		\
+    __libc_sigaction (SIGSEGV, &act, NULL);		\
   }								\
 while (0)  
 
@@ -71,7 +99,7 @@ do								\
     act.sa_sigaction = _Jv_catch_fpe;				\
     sigemptyset (&act.sa_mask);					\
     act.sa_flags = SA_SIGINFO;		       			\
-    syscall (SYS_sigaction, SIGFPE, &act, NULL);		\
+    __libc_sigaction (SIGFPE, &act, NULL);		\
   }								\
 while (0)