Use va_copy if available for VARARGS_ASSIGN

Bug #187180 r=blizzard sr=brendan

configure.in

@@ -2228,33 +2228,80 @@ esac
 
 AC_LANG_C
 
-dnl Does this platform require array notation to assign to a va_list?
-dnl If cross-compiling, we assume va_list is "normal".  If this breaks
-dnl you, set ac_cv_valistisarray=true and maybe define HAVE_VA_LIST_AS_ARRAY
-dnl also just to be sure.
-AC_MSG_CHECKING(whether va_list assignments need array notation)
-AC_CACHE_VAL(ac_cv_valistisarray,
-	[AC_TRY_RUN([#include <stdlib.h>
-		     #include <stdarg.h>
-		     void foo(int i, ...) {
-			va_list ap1, ap2;
-			va_start(ap1, i);
-			ap2 = ap1;
-			if (va_arg(ap2, int) != 123 || va_arg(ap1, int) != 123) { exit(1); }
-			va_end(ap1); va_end(ap2);
-		     }
-		     int main() { foo(0, 123); return(0); }],
-		    [ac_cv_valistisarray=false],
-		    [ac_cv_valistisarray=true],
-		    [ac_cv_valistisarray=false])])
-
-if test "$ac_cv_valistisarray" = true ; then
-	AC_DEFINE(HAVE_VA_LIST_AS_ARRAY)
-	AC_MSG_RESULT(yes)
-else
-	AC_MSG_RESULT(no)
+dnl **********************
+dnl *** va_copy checks ***
+dnl **********************
+dnl we currently check for all three va_copy possibilities, so we get
+dnl all results in config.log for bug reports.
+AC_MSG_CHECKING(for an implementation of va_copy())
+AC_CACHE_VAL(ac_cv_va_copy,[
+    AC_TRY_RUN([
+        #include <stdarg.h>
+        void f (int i, ...) {
+            va_list args1, args2;
+            va_start (args1, i);
+            va_copy (args2, args1);
+            if (va_arg (args2, int) != 42 || va_arg (args1, int) != 42)
+                exit (1);
+            va_end (args1); va_end (args2);
+        }
+        int main() { f (0, 42); return 0; }],
+        ac_cv_va_copy=yes,
+        ac_cv_va_copy=no,
+        ac_cv_va_copy=no
+    )
+])
+AC_MSG_RESULT($ac_cv_va_copy)
+AC_MSG_CHECKING(for an implementation of __va_copy())
+AC_CACHE_VAL(ac_cv___va_copy,[
+    AC_TRY_RUN([
+        #include <stdarg.h>
+        void f (int i, ...) {
+            va_list args1, args2;
+            va_start (args1, i);
+            __va_copy (args2, args1);
+            if (va_arg (args2, int) != 42 || va_arg (args1, int) != 42)
+                exit (1);
+            va_end (args1); va_end (args2);
+        }
+        int main() { f (0, 42); return 0; }],
+        ac_cv___va_copy=yes,
+        ac_cv___va_copy=no,
+        ac_cv___va_copy=no
+    )
+])
+AC_MSG_RESULT($ac_cv___va_copy)
+AC_MSG_CHECKING(whether va_lists can be copied by value)
+AC_CACHE_VAL(ac_cv_va_val_copy,[
+    AC_TRY_RUN([
+        #include <stdarg.h>
+        void f (int i, ...) {
+            va_list args1, args2;
+            va_start (args1, i);
+            args2 = args1;
+            if (va_arg (args2, int) != 42 || va_arg (args1, int) != 42)
+                exit (1);
+            va_end (args1); va_end (args2);
+        }
+        int main() { f (0, 42); return 0; }],
+        ac_cv_va_val_copy=yes,
+        ac_cv_va_val_copy=no,
+        ac_cv_va_val_copy=yes
+    )
+])
+if test "x$ac_cv_va_copy" = "xyes"; then
+    AC_DEFINE(VA_COPY, va_copy)
+    AC_DEFINE(HAVE_VA_COPY)
+elif test "x$ac_cv___va_copy" = "xyes"; then
+    AC_DEFINE(VA_COPY, __va_copy)
+    AC_DEFINE(HAVE_VA_COPY)
 fi
 
+if test "x$ac_cv_va_val_copy" = "xno"; then
+   AC_DEFINE(HAVE_VA_LIST_AS_ARRAY)
+fi
+AC_MSG_RESULT($ac_cv_va_val_copy)
+
 dnl Check for dll-challenged libc's.
 dnl This check is apparently only needed for Linux.
 case "$target" in

js/src/jsprf.c

@@ -50,7 +50,9 @@
 ** Note: on some platforms va_list is defined as an array,
 ** and requires array notation.
 */
-#ifdef HAVE_VA_LIST_AS_ARRAY
+#ifdef HAVE_VA_COPY
+#define VARARGS_ASSIGN(foo, bar)        VA_COPY(foo,bar)
+#elif defined(HAVE_VA_LIST_AS_ARRAY)
 #define VARARGS_ASSIGN(foo, bar)        foo[0] = bar[0]
 #else
 #define VARARGS_ASSIGN(foo, bar)        (foo) = (bar)

js/src/xpconnect/src/xpcconvert.cpp

@@ -1441,7 +1441,9 @@ XPCConvert::JSErrorToXPCException(XPCCallContext& ccx,
 ** Note: on some platforms va_list is defined as an array,
 ** and requires array notation.
 */
-#ifdef HAVE_VA_LIST_AS_ARRAY
+#ifdef HAVE_VA_COPY
+#define VARARGS_ASSIGN(foo, bar)	VA_COPY(foo,bar)
+#elif defined(HAVE_VA_LIST_AS_ARRAY)
 #define VARARGS_ASSIGN(foo, bar)	foo[0] = bar[0]
 #else
 #define VARARGS_ASSIGN(foo, bar)	(foo) = (bar)

xpcom/ds/nsTextFormatter.cpp

@@ -46,7 +46,9 @@
 ** and requires array notation.
 */
 
-#ifdef HAVE_VA_LIST_AS_ARRAY
+#ifdef HAVE_VA_COPY
+#define VARARGS_ASSIGN(foo, bar)        VA_COPY(foo,bar)
+#elif defined(HAVE_VA_LIST_AS_ARRAY)
 #define VARARGS_ASSIGN(foo, bar)	foo[0] = bar[0]
 #else
 #define VARARGS_ASSIGN(foo, bar)	(foo) = (bar)