diff --git a/js/src/dtoa.c b/js/src/dtoa.c
index ebdec083329..24f6a338268 100644
--- a/js/src/dtoa.c
+++ b/js/src/dtoa.c
@@ -1,3 +1,4 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
 /****************************************************************
  *
  * The author of this software is David M. Gay.
@@ -141,11 +142,6 @@
  *	floating-point numbers and flushes underflows to zero rather
  *	than implementing gradual underflow, then you must also #define
  *	Sudden_Underflow.
- * #define YES_ALIAS to permit aliasing certain double values with
- *	arrays of ULongs.  This leads to slightly better code with
- *	some compilers and was always used prior to 19990916, but it
- *	is not strictly legal and can cause trouble with aggressively
- *	optimizing compilers (e.g., gcc 2.95.1 under -O2).
  * #define USE_LOCALE to use the current locale's decimal_point value.
  * #define SET_INEXACT if IEEE arithmetic is being used and extra
  *	computation should be done to set the inexact flag when the
@@ -277,24 +273,13 @@ Exactly one of IEEE_8087, IEEE_MC68k, VAX, or IBM should be defined.
 
 typedef union { double d; ULong L[2]; } U;
 
-#ifdef YES_ALIAS
-#define dval(x) x
+#define dval(x) ((x).d)
 #ifdef IEEE_8087
-#define word0(x) ((ULong *)&x)[1]
-#define word1(x) ((ULong *)&x)[0]
+#define word0(x) ((x).L[1])
+#define word1(x) ((x).L[0])
 #else
-#define word0(x) ((ULong *)&x)[0]
-#define word1(x) ((ULong *)&x)[1]
-#endif
-#else
-#ifdef IEEE_8087
-#define word0(x) ((U*)&x)->L[1]
-#define word1(x) ((U*)&x)->L[0]
-#else
-#define word0(x) ((U*)&x)->L[0]
-#define word1(x) ((U*)&x)->L[1]
-#endif
-#define dval(x) ((U*)&x)->d
+#define word0(x) ((x).L[0])
+#define word1(x) ((x).L[1])
 #endif
 
 /* The following definition of Storeinc is appropriate for MIPS processors.
@@ -1103,13 +1088,13 @@ diff
  static double
 ulp
 #ifdef KR_headers
-	(x) double x;
+	(x) U x;
 #else
-	(double x)
+	(U x)
 #endif
 {
 	register Long L;
-	double a;
+	U a;
 
 	L = (word0(x) & Exp_mask) - (P-1)*Exp_msk1;
 #ifndef Avoid_Underflow
@@ -1152,7 +1137,7 @@ b2d
 {
 	ULong *xa, *xa0, w, y, z;
 	int k;
-	double d;
+	U d;
 #ifdef VAX
 	ULong d0, d1;
 #else
@@ -1215,9 +1200,9 @@ b2d
  static Bigint *
 d2b
 #ifdef KR_headers
-	(d, e, bits) double d; int *e, *bits;
+	(d, e, bits) U d; int *e, *bits;
 #else
-	(double d, int *e, int *bits)
+	(U d, int *e, int *bits)
 #endif
 {
 	Bigint *b;
@@ -1358,7 +1343,7 @@ ratio
 	(Bigint *a, Bigint *b)
 #endif
 {
-	double da, db;
+	U da, db;
 	int k, ka, kb;
 
 	dval(da) = b2d(a, &ka);
@@ -1463,9 +1448,9 @@ match
  static void
 hexnan
 #ifdef KR_headers
-	(rvp, sp) double *rvp; CONST char **sp;
+	(rvp, sp) U *rvp; CONST char **sp;
 #else
-	(double *rvp, CONST char **sp)
+	(U *rvp, CONST char **sp)
 #endif
 {
 	ULong c, x[2];
@@ -1545,7 +1530,8 @@ _strtod
 	int bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, dsign,
 		 e, e1, esign, i, j, k, nd, nd0, nf, nz, nz0, sign;
 	CONST char *s, *s0, *s1;
-	double aadj, aadj1, adj, rv, rv0;
+	double aadj, adj;
+	U aadj1, rv, rv0;
 	Long L;
 	ULong y, z;
 	Bigint *bb, *bb1, *bd, *bd0, *bs, *delta;
@@ -1560,7 +1546,7 @@ _strtod
 #endif
 
 #ifdef __GNUC__
-    delta = bb = bd = bs = 0;
+	delta = bb = bd = bs = 0;
 #endif
 
 	sign = nz0 = nz = 0;
@@ -1962,7 +1948,7 @@ _strtod
 	for(;;) {
 		bd = Balloc(bd0->k);
 		Bcopy(bd, bd0);
-		bb = d2b(dval(rv), &bbe, &bbbits);	/* rv = bb * 2^bbe */
+		bb = d2b(rv, &bbe, &bbbits);	/* rv = bb * 2^bbe */
 		bs = i2b(1);
 
 		if (e >= 0) {
@@ -2079,13 +2065,13 @@ _strtod
 					if ((word0(rv) & Exp_mask) <=
 							P*Exp_msk1) {
 						word0(rv) += P*Exp_msk1;
-						dval(rv) += adj*ulp(dval(rv));
+						dval(rv) += adj*ulp(rv);
 						word0(rv) -= P*Exp_msk1;
 						}
 					else
 #endif /*Sudden_Underflow*/
 #endif /*Avoid_Underflow*/
-					dval(rv) += adj*ulp(dval(rv));
+					dval(rv) += adj*ulp(rv);
 					}
 				break;
 				}
@@ -2108,7 +2094,7 @@ _strtod
 #ifdef Sudden_Underflow
 			if ((word0(rv) & Exp_mask) <= P*Exp_msk1) {
 				word0(rv) += P*Exp_msk1;
-				adj *= ulp(dval(rv));
+				adj *= ulp(rv);
 				if (dsign)
 					dval(rv) += adj;
 				else
@@ -2118,7 +2104,7 @@ _strtod
 				}
 #endif /*Sudden_Underflow*/
 #endif /*Avoid_Underflow*/
-			adj *= ulp(dval(rv));
+			adj *= ulp(rv);
 			if (dsign)
 				dval(rv) += adj;
 			else
@@ -2227,10 +2213,10 @@ _strtod
 				break;
 #endif
 			if (dsign)
-				dval(rv) += ulp(dval(rv));
+				dval(rv) += ulp(rv);
 #ifndef ROUND_BIASED
 			else {
-				dval(rv) -= ulp(dval(rv));
+				dval(rv) -= ulp(rv);
 #ifndef Sudden_Underflow
 				if (!dval(rv))
 					goto undfl;
@@ -2244,14 +2230,14 @@ _strtod
 			}
 		if ((aadj = ratio(delta, bs)) <= 2.) {
 			if (dsign)
-				aadj = aadj1 = 1.;
+				aadj = dval(aadj1) = 1.;
 			else if (word1(rv) || word0(rv) & Bndry_mask) {
 #ifndef Sudden_Underflow
 				if (word1(rv) == Tiny1 && !word0(rv))
 					goto undfl;
 #endif
 				aadj = 1.;
-				aadj1 = -1.;
+				dval(aadj1) = -1.;
 				}
 			else {
 				/* special case -- power of FLT_RADIX to be */
@@ -2261,24 +2247,24 @@ _strtod
 					aadj = 1./FLT_RADIX;
 				else
 					aadj *= 0.5;
-				aadj1 = -aadj;
+				dval(aadj1) = -aadj;
 				}
 			}
 		else {
 			aadj *= 0.5;
-			aadj1 = dsign ? aadj : -aadj;
+			dval(aadj1) = dsign ? aadj : -aadj;
 #ifdef Check_FLT_ROUNDS
 			switch(Rounding) {
 				case 2: /* towards +infinity */
-					aadj1 -= 0.5;
+					dval(aadj1) -= 0.5;
 					break;
 				case 0: /* towards 0 */
 				case 3: /* towards -infinity */
-					aadj1 += 0.5;
+					dval(aadj1) += 0.5;
 				}
 #else
 			if (Flt_Rounds == 0)
-				aadj1 += 0.5;
+				dval(aadj1) += 0.5;
 #endif /*Check_FLT_ROUNDS*/
 			}
 		y = word0(rv) & Exp_mask;
@@ -2288,7 +2274,7 @@ _strtod
 		if (y == Exp_msk1*(DBL_MAX_EXP+Bias-1)) {
 			dval(rv0) = dval(rv);
 			word0(rv) -= P*Exp_msk1;
-			adj = aadj1 * ulp(dval(rv));
+			adj = dval(aadj1) * ulp(rv);
 			dval(rv) += adj;
 			if ((word0(rv) & Exp_mask) >=
 					Exp_msk1*(DBL_MAX_EXP+Bias-P)) {
@@ -2308,18 +2294,18 @@ _strtod
 					if ((z = (ULong) aadj) <= 0)
 						z = 1;
 					aadj = z;
-					aadj1 = dsign ? aadj : -aadj;
+					dval(aadj1) = dsign ? aadj : -aadj;
 					}
 				word0(aadj1) += (2*P+1)*Exp_msk1 - y;
 				}
-			adj = aadj1 * ulp(dval(rv));
+			adj = dval(aadj1) * ulp(rv);
 			dval(rv) += adj;
 #else
 #ifdef Sudden_Underflow
 			if ((word0(rv) & Exp_mask) <= P*Exp_msk1) {
 				dval(rv0) = dval(rv);
 				word0(rv) += P*Exp_msk1;
-				adj = aadj1 * ulp(dval(rv));
+				adj = dval(aadj1) * ulp(rv);
 				dval(rv) += adj;
 #ifdef IBM
 				if ((word0(rv) & Exp_mask) <  P*Exp_msk1)
@@ -2338,7 +2324,7 @@ _strtod
 					word0(rv) -= P*Exp_msk1;
 				}
 			else {
-				adj = aadj1 * ulp(dval(rv));
+				adj = dval(aadj1) * ulp(rv);
 				dval(rv) += adj;
 				}
 #else /*Sudden_Underflow*/
@@ -2350,11 +2336,11 @@ _strtod
 			 * example: 1.2e-307 .
 			 */
 			if (y <= (P-1)*Exp_msk1 && aadj > 1.) {
-				aadj1 = (double)(int)(aadj + 0.5);
+				dval(aadj1) = (double)(int)(aadj + 0.5);
 				if (!dsign)
-					aadj1 = -aadj1;
+					dval(aadj1) = -dval(aadj1);
 				}
-			adj = aadj1 * ulp(dval(rv));
+			adj = dval(aadj1) * ulp(rv);
 			dval(rv) += adj;
 #endif /*Sudden_Underflow*/
 #endif /*Avoid_Underflow*/
@@ -2646,9 +2632,9 @@ freedtoa(char *s)
 dtoa
 #ifdef KR_headers
 	(d, mode, ndigits, decpt, sign, rve)
-	double d; int mode, ndigits, *decpt, *sign; char **rve;
+	U d; int mode, ndigits, *decpt, *sign; char **rve;
 #else
-	(double d, int mode, int ndigits, int *decpt, int *sign, char **rve)
+	(U d, int mode, int ndigits, int *decpt, int *sign, char **rve)
 #endif
 {
  /*	Arguments ndigits, decpt, sign are similar to those
@@ -2694,7 +2680,8 @@ dtoa
 	ULong x;
 #endif
 	Bigint *b, *b1, *delta, *mlo, *mhi, *S;
-	double d2, ds, eps;
+	U d2, eps;
+	double ds;
 	char *s, *s0;
 #ifdef Honor_FLT_ROUNDS
 	int rounding;
@@ -2704,8 +2691,8 @@ dtoa
 #endif
 
 #ifdef __GNUC__
-    ilim = ilim1 = 0;
-    mlo = NULL;
+	ilim = ilim1 = 0;
+	mlo = NULL;
 #endif
 
 #ifndef MULTIPLE_THREADS
@@ -2761,7 +2748,7 @@ dtoa
 		}
 #endif
 
-	b = d2b(dval(d), &be, &bbits);
+	b = d2b(d, &be, &bbits);
 #ifdef Sudden_Underflow
 	i = (int)(word0(d) >> Exp_shift1 & (Exp_mask>>Exp_shift1));
 #else
diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index 4d06c661ee7..b2f0bd72d4a 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -1361,10 +1361,12 @@ JS_InitStandardClasses(JSContext *cx, JSObject *obj)
            js_InitDateClass(cx, obj);
 }
 
-#define CLASP(name)                 ((JSClass *)&js_##name##Class)
+#define CLASP(name)                 (&js_##name##Class)
+#define EXT_CLASP(name)             (&js_##name##Class.base)
 #define EAGER_ATOM(name)            ATOM_OFFSET(name), NULL
 #define EAGER_CLASS_ATOM(name)      CLASS_ATOM_OFFSET(name), NULL
 #define EAGER_ATOM_AND_CLASP(name)  EAGER_CLASS_ATOM(name), CLASP(name)
+#define EAGER_ATOM_AND_EXT_CLASP(name) EAGER_CLASS_ATOM(name), EXT_CLASP(name)
 #define LAZY_ATOM(name)             ATOM_OFFSET(lazy.name), js_##name##_str
 
 typedef struct JSStdName {
@@ -1415,8 +1417,8 @@ static JSStdName standard_class_atoms[] = {
 #endif
 #if JS_HAS_XML_SUPPORT
     {js_InitXMLClass,                   EAGER_ATOM_AND_CLASP(XML)},
-    {js_InitNamespaceClass,             EAGER_ATOM_AND_CLASP(Namespace)},
-    {js_InitQNameClass,                 EAGER_ATOM_AND_CLASP(QName)},
+    {js_InitNamespaceClass,             EAGER_ATOM_AND_EXT_CLASP(Namespace)},
+    {js_InitQNameClass,                 EAGER_ATOM_AND_EXT_CLASP(QName)},
 #endif
 #if JS_HAS_FILE_OBJECT
     {js_InitFileClass,                  EAGER_ATOM_AND_CLASP(File)},
diff --git a/js/src/jscntxt.cpp b/js/src/jscntxt.cpp
index 8476cd3170c..2c3815c6522 100644
--- a/js/src/jscntxt.cpp
+++ b/js/src/jscntxt.cpp
@@ -510,9 +510,7 @@ js_ContextIterator(JSRuntime *rt, JSBool unlocked, JSContext **iterp)
 
     if (unlocked)
         JS_LOCK_GC(rt);
-    if (!cx)
-        cx = (JSContext *)&rt->contextList;
-    cx = (JSContext *)cx->links.next;
+    cx = (JSContext *) (cx ? cx->links.next : rt->contextList.next);
     if (&cx->links == &rt->contextList)
         cx = NULL;
     *iterp = cx;
diff --git a/js/src/jsdbgapi.cpp b/js/src/jsdbgapi.cpp
index 63e1a952a74..6e2075779c6 100644
--- a/js/src/jsdbgapi.cpp
+++ b/js/src/jsdbgapi.cpp
@@ -86,7 +86,7 @@ FindTrap(JSRuntime *rt, JSScript *script, jsbytecode *pc)
     JSTrap *trap;
 
     for (trap = (JSTrap *)rt->trapList.next;
-         trap != (JSTrap *)&rt->trapList;
+         &trap->links != &rt->trapList;
          trap = (JSTrap *)trap->links.next) {
         if (trap->script == script && trap->pc == pc)
             return trap;
@@ -105,7 +105,8 @@ js_UntrapScriptCode(JSContext *cx, JSScript *script)
     rt = cx->runtime;
     DBG_LOCK(rt);
     for (trap = (JSTrap *)rt->trapList.next;
-         trap != (JSTrap *)&rt->trapList;
+         &trap->links !=
+                &rt->trapList;
          trap = (JSTrap *)trap->links.next) {
         if (trap->script == script &&
             (size_t)(trap->pc - script->code) < script->length) {
@@ -240,7 +241,7 @@ JS_ClearScriptTraps(JSContext *cx, JSScript *script)
     rt = cx->runtime;
     DBG_LOCK(rt);
     for (trap = (JSTrap *)rt->trapList.next;
-         trap != (JSTrap *)&rt->trapList;
+         &trap->links != &rt->trapList;
          trap = next) {
         next = (JSTrap *)trap->links.next;
         if (trap->script == script) {
@@ -264,7 +265,7 @@ JS_ClearAllTraps(JSContext *cx)
     rt = cx->runtime;
     DBG_LOCK(rt);
     for (trap = (JSTrap *)rt->trapList.next;
-         trap != (JSTrap *)&rt->trapList;
+         &trap->links != &rt->trapList;
          trap = next) {
         next = (JSTrap *)trap->links.next;
         sample = rt->debuggerMutations;
@@ -430,7 +431,7 @@ js_TraceWatchPoints(JSTracer *trc, JSObject *obj)
     rt = trc->context->runtime;
 
     for (wp = (JSWatchPoint *)rt->watchPointList.next;
-         wp != (JSWatchPoint *)&rt->watchPointList;
+         &wp->links != &rt->watchPointList;
          wp = (JSWatchPoint *)wp->links.next) {
         if (wp->object == obj) {
             TRACE_SCOPE_PROPERTY(trc, wp->sprop);
@@ -454,7 +455,7 @@ js_SweepWatchPoints(JSContext *cx)
     rt = cx->runtime;
     DBG_LOCK(rt);
     for (wp = (JSWatchPoint *)rt->watchPointList.next;
-         wp != (JSWatchPoint *)&rt->watchPointList;
+         &wp->links != &rt->watchPointList;
          wp = next) {
         next = (JSWatchPoint *)wp->links.next;
         if (js_IsAboutToBeFinalized(cx, wp->object)) {
@@ -481,7 +482,7 @@ FindWatchPoint(JSRuntime *rt, JSScope *scope, jsid id)
     JSWatchPoint *wp;
 
     for (wp = (JSWatchPoint *)rt->watchPointList.next;
-         wp != (JSWatchPoint *)&rt->watchPointList;
+         &wp->links != &rt->watchPointList;
          wp = (JSWatchPoint *)wp->links.next) {
         if (wp->object == scope->object && wp->sprop->id == id)
             return wp;
@@ -517,7 +518,7 @@ js_GetWatchedSetter(JSRuntime *rt, JSScope *scope,
     if (scope)
         DBG_LOCK(rt);
     for (wp = (JSWatchPoint *)rt->watchPointList.next;
-         wp != (JSWatchPoint *)&rt->watchPointList;
+         &wp->links != &rt->watchPointList;
          wp = (JSWatchPoint *)wp->links.next) {
         if ((!scope || wp->object == scope->object) && wp->sprop == sprop) {
             setter = wp->setter;
@@ -542,7 +543,7 @@ js_watch_set(JSContext *cx, JSObject *obj, jsval id, jsval *vp)
     rt = cx->runtime;
     DBG_LOCK(rt);
     for (wp = (JSWatchPoint *)rt->watchPointList.next;
-         wp != (JSWatchPoint *)&rt->watchPointList;
+         &wp->links != &rt->watchPointList;
          wp = (JSWatchPoint *)wp->links.next) {
         sprop = wp->sprop;
         if (wp->object == obj && SPROP_USERID(sprop) == id &&
@@ -860,7 +861,7 @@ JS_ClearWatchPoint(JSContext *cx, JSObject *obj, jsval id,
     rt = cx->runtime;
     DBG_LOCK(rt);
     for (wp = (JSWatchPoint *)rt->watchPointList.next;
-         wp != (JSWatchPoint *)&rt->watchPointList;
+         &wp->links != &rt->watchPointList;
          wp = (JSWatchPoint *)wp->links.next) {
         if (wp->object == obj && SPROP_USERID(wp->sprop) == id) {
             if (handlerp)
@@ -888,7 +889,7 @@ JS_ClearWatchPointsForObject(JSContext *cx, JSObject *obj)
     rt = cx->runtime;
     DBG_LOCK(rt);
     for (wp = (JSWatchPoint *)rt->watchPointList.next;
-         wp != (JSWatchPoint *)&rt->watchPointList;
+         &wp->links != &rt->watchPointList;
          wp = next) {
         next = (JSWatchPoint *)wp->links.next;
         if (wp->object == obj) {
@@ -914,7 +915,7 @@ JS_ClearAllWatchPoints(JSContext *cx)
     rt = cx->runtime;
     DBG_LOCK(rt);
     for (wp = (JSWatchPoint *)rt->watchPointList.next;
-         wp != (JSWatchPoint *)&rt->watchPointList;
+         &wp->links != &rt->watchPointList;
          wp = next) {
         next = (JSWatchPoint *)wp->links.next;
         sample = rt->debuggerMutations;
diff --git a/js/src/jsdtoa.cpp b/js/src/jsdtoa.cpp
index 8d7bf8ab9bc..48a15cfa725 100644
--- a/js/src/jsdtoa.cpp
+++ b/js/src/jsdtoa.cpp
@@ -139,8 +139,9 @@ JS_strtod(const char *s00, char **se, int *err)
 }
 
 JS_FRIEND_API(char *)
-JS_dtostr(char *buffer, size_t bufferSize, JSDToStrMode mode, int precision, double d)
+JS_dtostr(char *buffer, size_t bufferSize, JSDToStrMode mode, int precision, double dinput)
 {
+    U d;
     int decPt;        /* Offset of decimal point from first digit */
     int sign;         /* Nonzero if the sign bit was set in d */
     int nDigits;      /* Number of significand digits returned by js_dtoa */
@@ -155,10 +156,11 @@ JS_dtostr(char *buffer, size_t bufferSize, JSDToStrMode mode, int precision, dou
      * Change mode here rather than below because the buffer may not be large
      * enough to hold a large integer.
      */
-    if (mode == DTOSTR_FIXED && (d >= 1e21 || d <= -1e21))
+    if (mode == DTOSTR_FIXED && (dinput >= 1e21 || dinput <= -1e21))
         mode = DTOSTR_STANDARD;
 
     LOCK_DTOA();
+    dval(d) = dinput;
     numBegin = dtoa(d, dtoaModes[mode], precision, &decPt, &sign, &numEnd);
     if (!numBegin) {
         UNLOCK_DTOA();
@@ -352,28 +354,30 @@ static uint32 quorem2(Bigint *b, int32 k)
 #define BASEDIGIT(digit) ((char)(((digit) >= 10) ? 'a' - 10 + (digit) : '0' + (digit)))
 
 JS_FRIEND_API(char *)
-JS_dtobasestr(int base, double d)
+JS_dtobasestr(int base, double dinput)
 {
+    U d;
     char *buffer;        /* The output string */
     char *p;             /* Pointer to current position in the buffer */
     char *pInt;          /* Pointer to the beginning of the integer part of the string */
     char *q;
     uint32 digit;
-    double di;           /* d truncated to an integer */
-    double df;           /* The fractional part of d */
+    U di;                /* d truncated to an integer */
+    U df;                /* The fractional part of d */
 
     JS_ASSERT(base >= 2 && base <= 36);
 
+    dval(d) = dinput;
     buffer = (char*) malloc(DTOBASESTR_BUFFER_SIZE);
     if (buffer) {
         p = buffer;
-        if (d < 0.0
+        if (dval(d) < 0.0
 #if defined(XP_WIN) || defined(XP_OS2)
             && !((word0(d) & Exp_mask) == Exp_mask && ((word0(d) & Frac_mask) || word1(d))) /* Visual C++ doesn't know how to compare against NaN */
 #endif
            ) {
             *p++ = '-';
-            d = -d;
+            dval(d) = -dval(d);
         }
 
         /* Check for Infinity and NaN */
@@ -385,9 +389,9 @@ JS_dtobasestr(int base, double d)
         LOCK_DTOA();
         /* Output the integer part of d with the digits in reverse order. */
         pInt = p;
-        di = fd_floor(d);
-        if (di <= 4294967295.0) {
-            uint32 n = (uint32)di;
+        dval(di) = fd_floor(dval(d));
+        if (dval(di) <= 4294967295.0) {
+            uint32 n = (uint32)dval(di);
             if (n)
                 do {
                     uint32 m = n / base;
@@ -426,8 +430,8 @@ JS_dtobasestr(int base, double d)
             *q-- = ch;
         }
 
-        df = d - di;
-        if (df != 0.0) {
+        dval(df) = dval(d) - dval(di);
+        if (dval(df) != 0.0) {
             /* We have a fraction. */
             int e, bbits;
             int32 s2, done;