--- a/js/src/jsprf.cpp
+++ b/js/src/jsprf.cpp
@@ -882,67 +882,67 @@ GrowStuff(SprintfState* ss, const char* 
     }
     MOZ_ASSERT(size_t(ss->cur - ss->base) <= ss->maxlen);
     return true;
 }
 
 /*
  * sprintf into a js_malloc'd buffer
  */
-JS_PUBLIC_API(char*)
-JS_smprintf(const char* fmt, ...)
+char*
+mozilla::Smprintf(const char* fmt, ...)
 {
     va_list ap;
     char* rv;
 
     va_start(ap, fmt);
-    rv = JS_vsmprintf(fmt, ap);
+    rv = mozilla::Vsmprintf(fmt, ap);
     va_end(ap);
     return rv;
 }
 
 /*
- * Free memory allocated, for the caller, by JS_smprintf
+ * Free memory allocated, for the caller, by mozilla::Smprintf
  */
-JS_PUBLIC_API(void)
-JS_smprintf_free(char* mem)
+void
+mozilla::SmprintfFree(char* mem)
 {
     js_free(mem);
 }
 
-JS_PUBLIC_API(char*)
-JS_vsmprintf(const char* fmt, va_list ap)
+char*
+mozilla::Vsmprintf(const char* fmt, va_list ap)
 {
     SprintfState ss;
 
     ss.stuff = GrowStuff;
     ss.base = 0;
     ss.cur = 0;
     ss.maxlen = 0;
     if (!dosprintf(&ss, fmt, ap)) {
         js_free(ss.base);
         return 0;
     }
     return ss.base;
 }
 
-JS_PUBLIC_API(char*)
-JS_sprintf_append(char* last, const char* fmt, ...)
+char*
+mozilla::SmprintfAppend(char* last, const char* fmt, ...)
 {
     va_list ap;
     char* rv;
 
     va_start(ap, fmt);
-    rv = JS_vsprintf_append(last, fmt, ap);
+    rv = mozilla::VsmprintfAppend(last, fmt, ap);
     va_end(ap);
     return rv;
 }
 
-JS_PUBLIC_API(char*)
-JS_vsprintf_append(char* last, const char* fmt, va_list ap)
+char*
+mozilla::VsmprintfAppend(char* last, const char* fmt, va_list ap)
 {
     SprintfState ss;
 
     ss.stuff = GrowStuff;
     if (last) {
         size_t lastlen = strlen(last);
         ss.base = last;
         ss.cur = last + lastlen;
@@ -973,8 +973,41 @@ JS_vsprintf_append(char* last, const cha
 #undef TYPE_POINTER
 #undef TYPE_UNKNOWN
 
 #undef FLAG_LEFT
 #undef FLAG_SIGNED
 #undef FLAG_SPACED
 #undef FLAG_ZEROS
 #undef FLAG_NEG
+
+JS_PUBLIC_API(char*) JS_smprintf(const char* fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    char* result = mozilla::Vsmprintf(fmt, ap);
+    va_end(ap);
+    return result;
+}
+
+JS_PUBLIC_API(void) JS_smprintf_free(char* mem)
+{
+    mozilla::SmprintfFree(mem);
+}
+
+JS_PUBLIC_API(char*) JS_sprintf_append(char* last, const char* fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    char* result = mozilla::VsmprintfAppend(last, fmt, ap);
+    va_end(ap);
+    return result;
+}
+
+JS_PUBLIC_API(char*) JS_vsmprintf(const char* fmt, va_list ap)
+{
+    return mozilla::Vsmprintf(fmt, ap);
+}
+
+JS_PUBLIC_API(char*) JS_vsprintf_append(char* last, const char* fmt, va_list ap)
+{
+    return mozilla::VsmprintfAppend(last, fmt, ap);
+}

--- a/js/src/jsprf.h
+++ b/js/src/jsprf.h
@@ -24,43 +24,62 @@
 **      %c - character
 **      %p - pointer (deals with machine dependent pointer size)
 **      %f - float
 **      %g - float
 */
 
 #include "mozilla/IntegerPrintfMacros.h"
 #include "mozilla/SizePrintfMacros.h"
+#include "mozilla/Types.h"
 
 #include <stdarg.h>
 
 #include "jstypes.h"
 
+namespace mozilla {
+
 /*
 ** sprintf into a malloc'd buffer. Return a pointer to the malloc'd
-** buffer on success, nullptr on failure. Call "JS_smprintf_free" to release
+** buffer on success, nullptr on failure. Call "SmprintfFree" to release
 ** the memory returned.
 */
-extern JS_PUBLIC_API(char*) JS_smprintf(const char* fmt, ...)
+extern MFBT_API char* Smprintf(const char* fmt, ...)
     MOZ_FORMAT_PRINTF(1, 2);
 
 /*
-** Free the memory allocated, for the caller, by JS_smprintf
+** Free the memory allocated, for the caller, by Smprintf
 */
-extern JS_PUBLIC_API(void) JS_smprintf_free(char* mem);
+extern MFBT_API void SmprintfFree(char* mem);
 
 /*
 ** "append" sprintf into a malloc'd buffer. "last" is the last value of
 ** the malloc'd buffer. sprintf will append data to the end of last,
-** growing it as necessary using realloc. If last is nullptr, JS_sprintf_append
+** growing it as necessary using realloc. If last is nullptr, SmprintfAppend
 ** will allocate the initial string. The return value is the new value of
 ** last for subsequent calls, or nullptr if there is a malloc failure.
 */
-extern JS_PUBLIC_API(char*) JS_sprintf_append(char* last, const char* fmt, ...)
+extern MFBT_API char* SmprintfAppend(char* last, const char* fmt, ...)
     MOZ_FORMAT_PRINTF(2, 3);
 
 /*
 ** va_list forms of the above.
 */
+extern MFBT_API char* Vsmprintf(const char* fmt, va_list ap);
+extern MFBT_API char* VsmprintfAppend(char* last, const char* fmt, va_list ap);
+
+} // namespace mozilla
+
+/* Wrappers for mozilla::Smprintf and friends that are used throughout
+   JS.  */
+
+extern JS_PUBLIC_API(char*) JS_smprintf(const char* fmt, ...)
+    MOZ_FORMAT_PRINTF(1, 2);
+
+extern JS_PUBLIC_API(void) JS_smprintf_free(char* mem);
+
+extern JS_PUBLIC_API(char*) JS_sprintf_append(char* last, const char* fmt, ...)
+     MOZ_FORMAT_PRINTF(2, 3);
+
 extern JS_PUBLIC_API(char*) JS_vsmprintf(const char* fmt, va_list ap);
 extern JS_PUBLIC_API(char*) JS_vsprintf_append(char* last, const char* fmt, va_list ap);
 
 #endif /* jsprf_h */