diff -r 000000000000 -r 6474c204b198 js/src/jsnativestack.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jsnativestack.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,162 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "jsnativestack.h"
+
+#ifdef XP_WIN
+# include "jswin.h"
+
+#elif defined(XP_MACOSX) || defined(DARWIN) || defined(XP_UNIX)
+# include <pthread.h>
+
+# if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
+#  include <pthread_np.h>
+# endif
+
+# if defined(ANDROID)
+#  include <sys/types.h>
+#  include <unistd.h>
+# endif
+
+#else
+# error "Unsupported platform"
+
+#endif
+
+#if defined(XP_WIN)
+
+void *
+js::GetNativeStackBaseImpl()
+{
+# if defined(_M_IX86) && defined(_MSC_VER)
+    /*
+     * offset 0x18 from the FS segment register gives a pointer to
+     * the thread information block for the current thread
+     */
+    NT_TIB* pTib;
+    __asm {
+        MOV EAX, FS:[18h]
+        MOV pTib, EAX
+    }
+    return static_cast<void*>(pTib->StackBase);
+
+# elif defined(_M_X64)
+    PNT_TIB64 pTib = reinterpret_cast<PNT_TIB64>(NtCurrentTeb());
+    return reinterpret_cast<void*>(pTib->StackBase);
+
+# elif defined(_WIN32) && defined(__GNUC__)
+    NT_TIB* pTib;
+    asm ("movl %%fs:0x18, %0\n" : "=r" (pTib));
+    return static_cast<void*>(pTib->StackBase);
+
+# endif
+}
+
+#elif defined(SOLARIS)
+
+#include <ucontext.h>
+
+JS_STATIC_ASSERT(JS_STACK_GROWTH_DIRECTION < 0);
+
+void *
+js::GetNativeStackBaseImpl()
+{
+    stack_t st;
+    stack_getbounds(&st);
+    return static_cast<char*>(st.ss_sp) + st.ss_size;
+}
+
+#elif defined(AIX)
+
+#include <ucontext.h>
+
+JS_STATIC_ASSERT(JS_STACK_GROWTH_DIRECTION < 0);
+
+void *
+js::GetNativeStackBaseImpl()
+{
+    ucontext_t context;
+    getcontext(&context);
+    return static_cast<char*>(context.uc_stack.ss_sp) +
+        context.uc_stack.ss_size;
+}
+
+#else /* XP_UNIX */
+
+void *
+js::GetNativeStackBaseImpl()
+{
+    pthread_t thread = pthread_self();
+# if defined(XP_MACOSX) || defined(DARWIN)
+    return pthread_get_stackaddr_np(thread);
+
+# else
+    pthread_attr_t sattr;
+    pthread_attr_init(&sattr);
+#  if defined(__OpenBSD__)
+    stack_t ss;
+#  elif defined(PTHREAD_NP_H) || defined(_PTHREAD_NP_H_) || defined(NETBSD)
+    /* e.g. on FreeBSD 4.8 or newer, neundorf@kde.org */
+    pthread_attr_get_np(thread, &sattr);
+#  else
+    /*
+     * FIXME: this function is non-portable;
+     * other POSIX systems may have different np alternatives
+     */
+    pthread_getattr_np(thread, &sattr);
+#  endif
+
+    void *stackBase = 0;
+    size_t stackSize = 0;
+    int rc;
+# if defined(__OpenBSD__)
+    rc = pthread_stackseg_np(pthread_self(), &ss);
+    stackBase = (void*)((size_t) ss.ss_sp - ss.ss_size);
+    stackSize = ss.ss_size;
+# elif defined(ANDROID)
+    if (gettid() == getpid()) {
+        // bionic's pthread_attr_getstack doesn't tell the truth for the main
+        // thread (see bug 846670). So we scan /proc/self/maps to find the
+        // segment which contains the stack.
+        rc = -1;
+        FILE *fs = fopen("/proc/self/maps", "r");
+        if (fs) {
+            char line[100];
+            unsigned long stackAddr = (unsigned long)&sattr;
+            while (fgets(line, sizeof(line), fs) != nullptr) {
+                unsigned long stackStart;
+                unsigned long stackEnd;
+                if (sscanf(line, "%lx-%lx ", &stackStart, &stackEnd) == 2 &&
+                    stackAddr >= stackStart && stackAddr < stackEnd) {
+                    stackBase = (void *)stackStart;
+                    stackSize = stackEnd - stackStart;
+                    rc = 0;
+                    break;
+                }
+            }
+            fclose(fs);
+        }
+    } else
+        // For non main-threads pthread allocates the stack itself so it tells
+        // the truth.
+        rc = pthread_attr_getstack(&sattr, &stackBase, &stackSize);
+# else
+    rc = pthread_attr_getstack(&sattr, &stackBase, &stackSize);
+# endif
+    if (rc)
+        MOZ_CRASH();
+    JS_ASSERT(stackBase);
+    pthread_attr_destroy(&sattr);
+
+#  if JS_STACK_GROWTH_DIRECTION > 0
+    return stackBase;
+#  else
+    return static_cast<char*>(stackBase) + stackSize;
+#  endif
+# endif
+}
+
+#endif /* !XP_WIN */