Issue #1751 -- Remove XP_DARWIN

9 files changed, 13 insertions, 877 deletions

diff --git a/js/src/ds/MemoryProtectionExceptionHandler.cpp b/js/src/ds/MemoryProtectionExceptionHandler.cpp
index 06fabb5301..77df1f0d92 100644
--- a/js/src/ds/MemoryProtectionExceptionHandler.cpp
+++ b/js/src/ds/MemoryProtectionExceptionHandler.cpp
@@ -10,13 +10,10 @@
 
 #if defined(XP_WIN)
 # include "jswin.h"
-#elif defined(XP_UNIX) && !defined(XP_DARWIN)
+#elif defined(XP_UNIX)
 # include <signal.h>
 # include <sys/types.h>
 # include <unistd.h>
-#elif defined(XP_DARWIN)
-# include <mach/mach.h>
-# include <unistd.h>
 #endif
 
 #ifdef ANDROID
@@ -210,7 +207,7 @@ MemoryProtectionExceptionHandler::uninstall()
     }
 }
 
-#elif defined(XP_UNIX) && !defined(XP_DARWIN)
+#elif defined(XP_UNIX)
 
 static struct sigaction sPrevSEGVHandler = {};
 
@@ -291,465 +288,6 @@ MemoryProtectionExceptionHandler::uninstall()
     }
 }
 
-#elif defined(XP_DARWIN)
-
-/*
- * The fact that we need to be able to forward to other exception handlers
- * makes this code much more complicated. The forwarding logic and the
- * structures required to make it work are heavily based on the code at
- * www.ravenbrook.com/project/mps/prototype/2013-06-24/machtest/machtest/main.c
- */
-
-/* -------------------------------------------------------------------------- */
-/*                Begin Mach definitions and helper functions                 */
-/* -------------------------------------------------------------------------- */
-
-/*
- * These are the message IDs associated with each exception type.
- * We'll be using sIDRequest64, but we need the others for forwarding.
- */
-static const mach_msg_id_t sIDRequest32 = 2401;
-static const mach_msg_id_t sIDRequestState32 = 2402;
-static const mach_msg_id_t sIDRequestStateIdentity32 = 2403;
-
-static const mach_msg_id_t sIDRequest64 = 2405;
-static const mach_msg_id_t sIDRequestState64 = 2406;
-static const mach_msg_id_t sIDRequestStateIdentity64 = 2407;
-
-/*
- * Each message ID has an associated Mach message structure.
- * We use the preprocessor to make defining them a little less arduous.
- */
-# define REQUEST_HEADER_FIELDS\
-    mach_msg_header_t header;
-
-# define REQUEST_IDENTITY_FIELDS\
-    mach_msg_body_t msgh_body;\
-    mach_msg_port_descriptor_t thread;\
-    mach_msg_port_descriptor_t task;
-
-# define REQUEST_GENERAL_FIELDS(bits)\
-    NDR_record_t NDR;\
-    exception_type_t exception;\
-    mach_msg_type_number_t code_count;\
-    int##bits##_t code[2];
-
-# define REQUEST_STATE_FIELDS\
-    int flavor;\
-    mach_msg_type_number_t old_state_count;\
-    natural_t old_state[THREAD_STATE_MAX];
-
-# define REQUEST_TRAILER_FIELDS\
-    mach_msg_trailer_t trailer;
-
-# define EXCEPTION_REQUEST(bits)\
-    struct ExceptionRequest##bits\
-    {\
-        REQUEST_HEADER_FIELDS\
-        REQUEST_IDENTITY_FIELDS\
-        REQUEST_GENERAL_FIELDS(bits)\
-        REQUEST_TRAILER_FIELDS\
-    };\
-
-# define EXCEPTION_REQUEST_STATE(bits)\
-    struct ExceptionRequestState##bits\
-    {\
-        REQUEST_HEADER_FIELDS\
-        REQUEST_GENERAL_FIELDS(bits)\
-        REQUEST_STATE_FIELDS\
-        REQUEST_TRAILER_FIELDS\
-    };\
-
-# define EXCEPTION_REQUEST_STATE_IDENTITY(bits)\
-    struct ExceptionRequestStateIdentity##bits\
-    {\
-        REQUEST_HEADER_FIELDS\
-        REQUEST_IDENTITY_FIELDS\
-        REQUEST_GENERAL_FIELDS(bits)\
-        REQUEST_STATE_FIELDS\
-        REQUEST_TRAILER_FIELDS\
-    };\
-
-/* This is needed because not all fields are naturally aligned on 64-bit. */
-# ifdef  __MigPackStructs
-#  pragma pack(4)
-# endif
-
-EXCEPTION_REQUEST(32)
-EXCEPTION_REQUEST(64)
-EXCEPTION_REQUEST_STATE(32)
-EXCEPTION_REQUEST_STATE(64)
-EXCEPTION_REQUEST_STATE_IDENTITY(32)
-EXCEPTION_REQUEST_STATE_IDENTITY(64)
-
-/* We use this as a common base when forwarding to the previous handler. */
-union ExceptionRequestUnion {
-    mach_msg_header_t header;
-    ExceptionRequest32 r32;
-    ExceptionRequest64 r64;
-    ExceptionRequestState32 rs32;
-    ExceptionRequestState64 rs64;
-    ExceptionRequestStateIdentity32 rsi32;
-    ExceptionRequestStateIdentity64 rsi64;
-};
-
-/* This isn't really a full Mach message, but it's all we need to send. */
-struct ExceptionReply
-{
-    mach_msg_header_t header;
-    NDR_record_t NDR;
-    kern_return_t RetCode;
-};
-
-# ifdef  __MigPackStructs
-#  pragma pack()
-# endif
-
-# undef EXCEPTION_REQUEST_STATE_IDENTITY
-# undef EXCEPTION_REQUEST_STATE
-# undef EXCEPTION_REQUEST
-# undef REQUEST_STATE_FIELDS
-# undef REQUEST_GENERAL_FIELDS
-# undef REQUEST_IDENTITY_FIELDS
-# undef REQUEST_HEADER_FIELDS
-
-/*
- * The exception handler we're forwarding to may not have the same behavior
- * or thread state flavor as what we're using. These macros help populate
- * the fields of the message we're about to send to the previous handler.
- */
-# define COPY_REQUEST_COMMON(bits, id)\
-    dst.header = src.header;\
-    dst.header.msgh_id = id;\
-    dst.header.msgh_size = static_cast<mach_msg_size_t>(sizeof(dst) - sizeof(dst.trailer));\
-    dst.NDR = src.NDR;\
-    dst.exception = src.exception;\
-    dst.code_count = src.code_count;\
-    dst.code[0] = int##bits##_t(src.code[0]);\
-    dst.code[1] = int##bits##_t(src.code[1]);
-
-# define COPY_REQUEST_IDENTITY\
-    dst.msgh_body = src.msgh_body;\
-    dst.thread = src.thread;\
-    dst.task = src.task;
-
-# define COPY_REQUEST_STATE(flavor, stateCount, state)\
-    mach_msg_size_t stateSize = stateCount * sizeof(natural_t);\
-    dst.header.msgh_size = static_cast<mach_msg_size_t>(sizeof(dst) - sizeof(dst.trailer) -\
-                                                        sizeof(dst.old_state) + stateSize);\
-    dst.flavor = flavor;\
-    dst.old_state_count = stateCount;\
-    memcpy(dst.old_state, state, stateSize);
-
-# define COPY_EXCEPTION_REQUEST(bits)\
-    static void\
-    CopyExceptionRequest##bits(ExceptionRequest64& src,\
-                               ExceptionRequest##bits& dst)\
-    {\
-        COPY_REQUEST_COMMON(bits, sIDRequest##bits)\
-        COPY_REQUEST_IDENTITY\
-    }
-
-# define COPY_EXCEPTION_REQUEST_STATE(bits)\
-    static void\
-    CopyExceptionRequestState##bits(ExceptionRequest64& src,\
-                                    ExceptionRequestState##bits& dst,\
-                                    thread_state_flavor_t flavor,\
-                                    mach_msg_type_number_t stateCount,\
-                                    thread_state_t state)\
-    {\
-        COPY_REQUEST_COMMON(bits, sIDRequestState##bits)\
-        COPY_REQUEST_STATE(flavor, stateCount, state)\
-    }
-
-# define COPY_EXCEPTION_REQUEST_STATE_IDENTITY(bits)\
-    static void\
-    CopyExceptionRequestStateIdentity##bits(ExceptionRequest64& src,\
-                                            ExceptionRequestStateIdentity##bits& dst,\
-                                            thread_state_flavor_t flavor,\
-                                            mach_msg_type_number_t stateCount,\
-                                            thread_state_t state)\
-    {\
-        COPY_REQUEST_COMMON(bits, sIDRequestStateIdentity##bits)\
-        COPY_REQUEST_IDENTITY\
-        COPY_REQUEST_STATE(flavor, stateCount, state)\
-    }
-
-COPY_EXCEPTION_REQUEST(32)
-COPY_EXCEPTION_REQUEST_STATE(32)
-COPY_EXCEPTION_REQUEST_STATE_IDENTITY(32)
-COPY_EXCEPTION_REQUEST(64)
-COPY_EXCEPTION_REQUEST_STATE(64)
-COPY_EXCEPTION_REQUEST_STATE_IDENTITY(64)
-
-# undef COPY_EXCEPTION_REQUEST_STATE_IDENTITY
-# undef COPY_EXCEPTION_REQUEST_STATE
-# undef COPY_EXCEPTION_REQUEST
-# undef COPY_REQUEST_STATE
-# undef COPY_REQUEST_IDENTITY
-# undef COPY_REQUEST_COMMON
-
-/* -------------------------------------------------------------------------- */
-/*                 End Mach definitions and helper functions                  */
-/* -------------------------------------------------------------------------- */
-
-/* Every Mach exception handler is parameterized by these four properties. */
-struct MachExceptionParameters
-{
-    exception_mask_t mask;
-    mach_port_t port;
-    exception_behavior_t behavior;
-    thread_state_flavor_t flavor;
-};
-
-struct ExceptionHandlerState
-{
-    MachExceptionParameters current;
-    MachExceptionParameters previous;
-
-    /* Each Mach exception handler runs in its own thread. */
-    Thread handlerThread;
-};
-
-/* This choice of ID is arbitrary, but must not match our exception ID. */
-static const mach_msg_id_t sIDQuit = 42;
-
-static ExceptionHandlerState sMachExceptionState;
-
-/*
- * The meat of our exception handler. This thread waits for an exception
- * message, annotates the exception if needed, then forwards it to the
- * previously installed handler (which will likely terminate the process).
- */
-static void
-MachExceptionHandler()
-{
-    kern_return_t ret;
-    MachExceptionParameters& current = sMachExceptionState.current;
-    MachExceptionParameters& previous = sMachExceptionState.previous;
-
-    // We use the simplest kind of 64-bit exception message here.
-    ExceptionRequest64 request = {};
-    request.header.msgh_local_port = current.port;
-    request.header.msgh_size = static_cast<mach_msg_size_t>(sizeof(request));
-    ret = mach_msg(&request.header, MACH_RCV_MSG, 0, request.header.msgh_size,
-                   current.port, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
-
-    // Restore the previous handler. We're going to forward to it
-    // anyway, and if we crash while doing so we don't want to hang.
-    task_set_exception_ports(mach_task_self(), previous.mask, previous.port,
-                             previous.behavior, previous.flavor);
-
-    // If we failed even receiving the message, just give up.
-    if (ret != MACH_MSG_SUCCESS)
-        MOZ_CRASH("MachExceptionHandler: mach_msg failed to receive a message!");
-
-    // Terminate the thread if we're shutting down.
-    if (request.header.msgh_id == sIDQuit)
-        return;
-
-    // The only other valid message ID is the one associated with the
-    // EXCEPTION_DEFAULT | MACH_EXCEPTION_CODES behavior we chose.
-    if (request.header.msgh_id != sIDRequest64)
-        MOZ_CRASH("MachExceptionHandler: Unexpected Message ID!");
-
-    // Make sure we can understand the exception we received.
-    if (request.exception != EXC_BAD_ACCESS || request.code_count != 2)
-        MOZ_CRASH("MachExceptionHandler: Unexpected exception type!");
-
-    // Get the address that the offending code tried to access.
-    uintptr_t address = uintptr_t(request.code[1]);
-
-    // If the faulting address is inside one of our protected regions, we
-    // want to annotate the crash to make it stand out from the crowd.
-    if (sProtectedRegions.isProtected(address)) {
-        ReportCrashIfDebug("Hit MOZ_CRASH(Tried to access a protected region!)\n");
-        MOZ_CRASH_ANNOTATE("MOZ_CRASH(Tried to access a protected region!)");
-    }
-
-    // Forward to the previous handler which may be a debugger, the unix
-    // signal handler, the crash reporter or something else entirely.
-    if (previous.port != MACH_PORT_NULL) {
-        mach_msg_type_number_t stateCount;
-        thread_state_data_t state;
-        if ((uint32_t(previous.behavior) & ~MACH_EXCEPTION_CODES) != EXCEPTION_DEFAULT) {
-            // If the previous handler requested thread state, get it here.
-            stateCount = THREAD_STATE_MAX;
-            ret = thread_get_state(request.thread.name, previous.flavor, state, &stateCount);
-            if (ret != KERN_SUCCESS)
-                MOZ_CRASH("MachExceptionHandler: Could not get the thread state to forward!");
-        }
-
-        // Depending on the behavior of the previous handler, the forwarded
-        // exception message will have a different set of fields.
-        // Of particular note is that exception handlers that lack
-        // MACH_EXCEPTION_CODES will get 32-bit fields even on 64-bit
-        // systems. It appears that OSX simply truncates these fields.
-        ExceptionRequestUnion forward;
-        switch (uint32_t(previous.behavior)) {
-          case EXCEPTION_DEFAULT:
-             CopyExceptionRequest32(request, forward.r32);
-             break;
-          case EXCEPTION_DEFAULT | MACH_EXCEPTION_CODES:
-             CopyExceptionRequest64(request, forward.r64);
-             break;
-          case EXCEPTION_STATE:
-             CopyExceptionRequestState32(request, forward.rs32,
-                                         previous.flavor, stateCount, state);
-             break;
-          case EXCEPTION_STATE | MACH_EXCEPTION_CODES:
-             CopyExceptionRequestState64(request, forward.rs64,
-                                         previous.flavor, stateCount, state);
-             break;
-          case EXCEPTION_STATE_IDENTITY:
-             CopyExceptionRequestStateIdentity32(request, forward.rsi32,
-                                                 previous.flavor, stateCount, state);
-             break;
-          case EXCEPTION_STATE_IDENTITY | MACH_EXCEPTION_CODES:
-             CopyExceptionRequestStateIdentity64(request, forward.rsi64,
-                                                 previous.flavor, stateCount, state);
-             break;
-          default:
-             MOZ_CRASH("MachExceptionHandler: Unknown previous handler behavior!");
-        }
-
-        // Forward the generated message to the old port. The local and remote
-        // port fields *and their rights* are swapped on arrival, so we need to
-        // swap them back first.
-        forward.header.msgh_bits = (request.header.msgh_bits & ~MACH_MSGH_BITS_PORTS_MASK) |
-            MACH_MSGH_BITS(MACH_MSGH_BITS_LOCAL(request.header.msgh_bits),
-                           MACH_MSGH_BITS_REMOTE(request.header.msgh_bits));
-        forward.header.msgh_local_port = forward.header.msgh_remote_port;
-        forward.header.msgh_remote_port = previous.port;
-        ret = mach_msg(&forward.header, MACH_SEND_MSG, forward.header.msgh_size, 0,
-                       MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
-        if (ret != MACH_MSG_SUCCESS)
-            MOZ_CRASH("MachExceptionHandler: Failed to forward to the previous handler!");
-    } else {
-        // There was no previous task-level exception handler, so defer to the
-        // host level one instead. We set the return code to KERN_FAILURE to
-        // indicate that we did not handle the exception.
-        // The reply message ID is always the request ID + 100.
-        ExceptionReply reply = {};
-        reply.header.msgh_bits =
-            MACH_MSGH_BITS(MACH_MSGH_BITS_REMOTE(request.header.msgh_bits), 0);
-        reply.header.msgh_size = static_cast<mach_msg_size_t>(sizeof(reply));
-        reply.header.msgh_remote_port = request.header.msgh_remote_port;
-        reply.header.msgh_local_port = MACH_PORT_NULL;
-        reply.header.msgh_id = request.header.msgh_id + 100;
-        reply.NDR = request.NDR;
-        reply.RetCode = KERN_FAILURE;
-        ret = mach_msg(&reply.header, MACH_SEND_MSG, reply.header.msgh_size, 0,
-                       MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
-        if (ret != MACH_MSG_SUCCESS)
-            MOZ_CRASH("MachExceptionHandler: Failed to forward to the host level!");
-    }
-}
-
-static void
-TerminateMachExceptionHandlerThread()
-{
-    // Send a simple quit message to the exception handler thread.
-    mach_msg_header_t msg;
-    msg.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
-    msg.msgh_size = static_cast<mach_msg_size_t>(sizeof(msg));
-    msg.msgh_remote_port = sMachExceptionState.current.port;
-    msg.msgh_local_port = MACH_PORT_NULL;
-    msg.msgh_reserved = 0;
-    msg.msgh_id = sIDQuit;
-    kern_return_t ret = mach_msg(&msg, MACH_SEND_MSG, sizeof(msg), 0, MACH_PORT_NULL,
-                                 MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
-
-    if (ret == MACH_MSG_SUCCESS)
-        sMachExceptionState.handlerThread.join();
-    else
-        MOZ_CRASH("MachExceptionHandler: Handler thread failed to terminate!");
-}
-
-bool
-MemoryProtectionExceptionHandler::install()
-{
-    MOZ_ASSERT(!sExceptionHandlerInstalled);
-
-    // If the exception handler is disabled, report success anyway.
-    if (MemoryProtectionExceptionHandler::isDisabled())
-        return true;
-
-    kern_return_t ret;
-    mach_port_t task = mach_task_self();
-
-    // Allocate a new exception port with receive rights.
-    sMachExceptionState.current = {};
-    MachExceptionParameters& current = sMachExceptionState.current;
-    ret = mach_port_allocate(task, MACH_PORT_RIGHT_RECEIVE, &current.port);
-    if (ret != KERN_SUCCESS)
-        return false;
-
-    // Give the new port send rights as well.
-    ret = mach_port_insert_right(task, current.port, current.port, MACH_MSG_TYPE_MAKE_SEND);
-    if (ret != KERN_SUCCESS) {
-        mach_port_deallocate(task, current.port);
-        current = {};
-        return false;
-    }
-
-    // Start the thread that will receive the messages from our exception port.
-    if (!sMachExceptionState.handlerThread.init(MachExceptionHandler)) {
-        mach_port_deallocate(task, current.port);
-        current = {};
-        return false;
-    }
-
-    // Set the other properties of our new exception handler.
-    current.mask = EXC_MASK_BAD_ACCESS;
-    current.behavior = exception_behavior_t(EXCEPTION_DEFAULT | MACH_EXCEPTION_CODES);
-    current.flavor = THREAD_STATE_NONE;
-
-    // Tell the task to use our exception handler, and save the previous one.
-    sMachExceptionState.previous = {};
-    MachExceptionParameters& previous = sMachExceptionState.previous;
-    mach_msg_type_number_t previousCount = 1;
-    ret = task_swap_exception_ports(task, current.mask, current.port, current.behavior,
-                                    current.flavor, &previous.mask, &previousCount,
-                                    &previous.port, &previous.behavior, &previous.flavor);
-    if (ret != KERN_SUCCESS) {
-        TerminateMachExceptionHandlerThread();
-        mach_port_deallocate(task, current.port);
-        previous = {};
-        current = {};
-        return false;
-    }
-
-    // We should have info on the previous exception handler, even if it's null.
-    MOZ_ASSERT(previousCount == 1);
-
-    sExceptionHandlerInstalled = true;
-    return sExceptionHandlerInstalled;
-}
-
-void
-MemoryProtectionExceptionHandler::uninstall()
-{
-    if (sExceptionHandlerInstalled) {
-        mach_port_t task = mach_task_self();
-
-        // Restore the previous exception handler.
-        MachExceptionParameters& previous = sMachExceptionState.previous;
-        task_set_exception_ports(task, previous.mask, previous.port,
-                                 previous.behavior, previous.flavor);
-
-        TerminateMachExceptionHandlerThread();
-
-        // Release the Mach IPC port we used.
-        mach_port_deallocate(task, sMachExceptionState.current.port);
-
-        sMachExceptionState.current = {};
-        sMachExceptionState.previous = {};
-
-        sExceptionHandlerInstalled = false;
-    }
-}
-
 #else
 
 #error "This platform is not supported!"
diff --git a/js/src/jsmath.cpp b/js/src/jsmath.cpp
index ba1d29de0f..78760583db 100644
--- a/js/src/jsmath.cpp
+++ b/js/src/jsmath.cpp
@@ -49,7 +49,7 @@
 # undef SystemFunction036
 #endif
 
-#if defined(ANDROID) || defined(XP_DARWIN) || defined(__DragonFly__) || \
+#if defined(ANDROID) || defined(__DragonFly__) || \
     defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)
 # include <stdlib.h>
 # define HAVE_ARC4RANDOM
diff --git a/js/src/jsnativestack.cpp b/js/src/jsnativestack.cpp
index d83e06c241..99c2f6654a 100644
--- a/js/src/jsnativestack.cpp
+++ b/js/src/jsnativestack.cpp
@@ -8,7 +8,7 @@
 #ifdef XP_WIN
 # include "jswin.h"
 
-#elif defined(XP_DARWIN) || defined(DARWIN) || defined(XP_UNIX)
+#elif defined(XP_UNIX)
 # include <pthread.h>
 
 # if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
@@ -132,10 +132,6 @@ void*
 js::GetNativeStackBaseImpl()
 {
     pthread_t thread = pthread_self();
-# if defined(XP_DARWIN) || defined(DARWIN)
-    return pthread_get_stackaddr_np(thread);
-
-# else
     pthread_attr_t sattr;
     pthread_attr_init(&sattr);
 #  if defined(__OpenBSD__)
@@ -210,7 +206,6 @@ js::GetNativeStackBaseImpl()
 #  else
     return static_cast<char*>(stackBase) + stackSize;
 #  endif
-# endif
 }
 
 #endif /* !XP_WIN */
diff --git a/js/src/jsstr.cpp b/js/src/jsstr.cpp
index 6eb11b1cc1..b44fbdebca 100644
--- a/js/src/jsstr.cpp
+++ b/js/src/jsstr.cpp
@@ -1177,7 +1177,7 @@ FirstCharMatcher8bit(const char* text, uint32_t n, const char pat)
 static const char16_t*
 FirstCharMatcher16bit(const char16_t* text, uint32_t n, const char16_t pat)
 {
-#if defined(XP_DARWIN) || defined(XP_WIN)
+#if defined(XP_WIN)
     /*
      * Performance of memchr is horrible in OSX. Windows is better,
      * but it is still better to use UnrolledMatcher.
diff --git a/js/src/threading/posix/Thread.cpp b/js/src/threading/posix/Thread.cpp
index faca05c24d..a5c2d2eacb 100644
--- a/js/src/threading/posix/Thread.cpp
+++ b/js/src/threading/posix/Thread.cpp
@@ -151,9 +151,7 @@ js::ThisThread::SetName(const char* name)
 #endif
 
   int rv;
-#ifdef XP_DARWIN
-  rv = pthread_setname_np(name);
-#elif defined(__DragonFly__) || defined(__FreeBSD__) || defined(__OpenBSD__)
+#if defined(__DragonFly__) || defined(__FreeBSD__) || defined(__OpenBSD__)
   pthread_set_name_np(pthread_self(), name);
   rv = 0;
 #elif defined(__NetBSD__)
diff --git a/js/src/vm/Runtime.cpp b/js/src/vm/Runtime.cpp
index 251c8258cf..23c50814fc 100644
--- a/js/src/vm/Runtime.cpp
+++ b/js/src/vm/Runtime.cpp
@@ -10,14 +10,12 @@
 #include "mozilla/ThreadLocal.h"
 #include "mozilla/Unused.h"
 
-#if defined(XP_DARWIN)
-#include <mach/mach.h>
-#elif defined(XP_UNIX)
+#if defined(XP_UNIX)
 #include <sys/resource.h>
 #elif defined(XP_WIN)
 #include <processthreadsapi.h>
 #include <windows.h>
-#endif // defined(XP_DARWIN) || defined(XP_UNIX) || defined(XP_WIN)
+#endif // defined(XP_UNIX) || defined(XP_WIN)
 
 #include <locale.h>
 #include <string.h>
diff --git a/js/src/vm/Runtime.h b/js/src/vm/Runtime.h
index f1f2e07094..eefc90cb4c 100644
--- a/js/src/vm/Runtime.h
+++ b/js/src/vm/Runtime.h
@@ -21,9 +21,6 @@
 #include "jsclist.h"
 #include "jsscript.h"
 
-#ifdef XP_DARWIN
-# include "wasm/WasmSignalHandlers.h"
-#endif
 #include "builtin/AtomicsObject.h"
 #include "builtin/Intl.h"
 #include "builtin/Promise.h"
@@ -932,10 +929,6 @@ struct JSRuntime : public JS::shadow::Runtime,
      */
     JSCList             onNewGlobalObjectWatchers;
 
-#if defined(XP_DARWIN)
-    js::wasm::MachExceptionHandler wasmMachExceptionHandler;
-#endif
-
   private:
     js::FreeOp*         defaultFreeOp_;
 
diff --git a/js/src/wasm/WasmSignalHandlers.cpp b/js/src/wasm/WasmSignalHandlers.cpp
index b7bb024bca..b45d05ebd2 100644
--- a/js/src/wasm/WasmSignalHandlers.cpp
+++ b/js/src/wasm/WasmSignalHandlers.cpp
@@ -1,6 +1,7 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  *
  * Copyright 2014 Mozilla Foundation
+ * Copyright 2021 Moonchild Productions
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -235,10 +236,6 @@ class AutoSetHandlingSegFault
 #  define EPC_sig(p) ((p)->uc_mcontext.mc_pc)
 #  define RFP_sig(p) ((p)->uc_mcontext.mc_regs[30])
 # endif
-#elif defined(XP_DARWIN)
-# define EIP_sig(p) ((p)->uc_mcontext->__ss.__eip)
-# define RIP_sig(p) ((p)->uc_mcontext->__ss.__rip)
-# define R15_sig(p) ((p)->uc_mcontext->__ss.__pc)
 #else
 # error "Don't know how to read/write to the thread state via the mcontext_t."
 #endif
@@ -348,34 +345,8 @@ enum { REG_EIP = 14 };
 #endif
 
 // Define a context type for use in the emulator code. This is usually just
-// the same as CONTEXT, but on Mac we use a different structure since we call
-// into the emulator code from a Mach exception handler rather than a
-// sigaction-style signal handler.
-#if defined(XP_DARWIN)
-# if defined(JS_CPU_X64)
-struct macos_x64_context {
-    x86_thread_state64_t thread;
-    x86_float_state64_t float_;
-};
-#  define EMULATOR_CONTEXT macos_x64_context
-# elif defined(JS_CPU_X86)
-struct macos_x86_context {
-    x86_thread_state_t thread;
-    x86_float_state_t float_;
-};
-#  define EMULATOR_CONTEXT macos_x86_context
-# elif defined(JS_CPU_ARM)
-struct macos_arm_context {
-    arm_thread_state_t thread;
-    arm_neon_state_t float_;
-};
-#  define EMULATOR_CONTEXT macos_arm_context
-# else
-#  error Unsupported architecture
-# endif
-#else
+// the same as CONTEXT.
 # define EMULATOR_CONTEXT CONTEXT
-#endif
 
 #if defined(JS_CPU_X64)
 # define PC_sig(p) RIP_sig(p)
@@ -467,7 +438,6 @@ StoreValueFromGPImm(SharedMem<void*> addr, size_t size, int32_t imm)
     AtomicOperations::memcpySafeWhenRacy(addr, static_cast<void*>(&imm), size);
 }
 
-# if !defined(XP_DARWIN)
 MOZ_COLD static void*
 AddressOfFPRegisterSlot(CONTEXT* context, FloatRegisters::Encoding encoding)
 {
@@ -517,57 +487,6 @@ AddressOfGPRegisterSlot(EMULATOR_CONTEXT* context, Registers::Code code)
     }
     MOZ_CRASH();
 }
-# else
-MOZ_COLD static void*
-AddressOfFPRegisterSlot(EMULATOR_CONTEXT* context, FloatRegisters::Encoding encoding)
-{
-    switch (encoding) {
-      case X86Encoding::xmm0:  return &context->float_.__fpu_xmm0;
-      case X86Encoding::xmm1:  return &context->float_.__fpu_xmm1;
-      case X86Encoding::xmm2:  return &context->float_.__fpu_xmm2;
-      case X86Encoding::xmm3:  return &context->float_.__fpu_xmm3;
-      case X86Encoding::xmm4:  return &context->float_.__fpu_xmm4;
-      case X86Encoding::xmm5:  return &context->float_.__fpu_xmm5;
-      case X86Encoding::xmm6:  return &context->float_.__fpu_xmm6;
-      case X86Encoding::xmm7:  return &context->float_.__fpu_xmm7;
-      case X86Encoding::xmm8:  return &context->float_.__fpu_xmm8;
-      case X86Encoding::xmm9:  return &context->float_.__fpu_xmm9;
-      case X86Encoding::xmm10: return &context->float_.__fpu_xmm10;
-      case X86Encoding::xmm11: return &context->float_.__fpu_xmm11;
-      case X86Encoding::xmm12: return &context->float_.__fpu_xmm12;
-      case X86Encoding::xmm13: return &context->float_.__fpu_xmm13;
-      case X86Encoding::xmm14: return &context->float_.__fpu_xmm14;
-      case X86Encoding::xmm15: return &context->float_.__fpu_xmm15;
-      default: break;
-    }
-    MOZ_CRASH();
-}
-
-MOZ_COLD static void*
-AddressOfGPRegisterSlot(EMULATOR_CONTEXT* context, Registers::Code code)
-{
-    switch (code) {
-      case X86Encoding::rax: return &context->thread.__rax;
-      case X86Encoding::rcx: return &context->thread.__rcx;
-      case X86Encoding::rdx: return &context->thread.__rdx;
-      case X86Encoding::rbx: return &context->thread.__rbx;
-      case X86Encoding::rsp: return &context->thread.__rsp;
-      case X86Encoding::rbp: return &context->thread.__rbp;
-      case X86Encoding::rsi: return &context->thread.__rsi;
-      case X86Encoding::rdi: return &context->thread.__rdi;
-      case X86Encoding::r8:  return &context->thread.__r8;
-      case X86Encoding::r9:  return &context->thread.__r9;
-      case X86Encoding::r10: return &context->thread.__r10;
-      case X86Encoding::r11: return &context->thread.__r11;
-      case X86Encoding::r12: return &context->thread.__r12;
-      case X86Encoding::r13: return &context->thread.__r13;
-      case X86Encoding::r14: return &context->thread.__r14;
-      case X86Encoding::r15: return &context->thread.__r15;
-      default: break;
-    }
-    MOZ_CRASH();
-}
-# endif  // !XP_DARWIN
 
 MOZ_COLD static void
 SetRegisterToCoercedUndefined(EMULATOR_CONTEXT* context, size_t size,
@@ -873,276 +792,7 @@ WasmFaultHandler(LPEXCEPTION_POINTERS exception)
     return EXCEPTION_CONTINUE_SEARCH;
 }
 
-#elif defined(XP_DARWIN)
-# include <mach/exc.h>
-
-static uint8_t**
-ContextToPC(EMULATOR_CONTEXT* context)
-{
-# if defined(JS_CPU_X64)
-    static_assert(sizeof(context->thread.__rip) == sizeof(void*),
-                  "stored IP should be compile-time pointer-sized");
-    return reinterpret_cast<uint8_t**>(&context->thread.__rip);
-# elif defined(JS_CPU_X86)
-    static_assert(sizeof(context->thread.uts.ts32.__eip) == sizeof(void*),
-                  "stored IP should be compile-time pointer-sized");
-    return reinterpret_cast<uint8_t**>(&context->thread.uts.ts32.__eip);
-# elif defined(JS_CPU_ARM)
-    static_assert(sizeof(context->thread.__pc) == sizeof(void*),
-                  "stored IP should be compile-time pointer-sized");
-    return reinterpret_cast<uint8_t**>(&context->thread.__pc);
-# else
-#  error Unsupported architecture
-# endif
-}
-
-// This definition was generated by mig (the Mach Interface Generator) for the
-// routine 'exception_raise' (exc.defs).
-#pragma pack(4)
-typedef struct {
-    mach_msg_header_t Head;
-    /* start of the kernel processed data */
-    mach_msg_body_t msgh_body;
-    mach_msg_port_descriptor_t thread;
-    mach_msg_port_descriptor_t task;
-    /* end of the kernel processed data */
-    NDR_record_t NDR;
-    exception_type_t exception;
-    mach_msg_type_number_t codeCnt;
-    int64_t code[2];
-} Request__mach_exception_raise_t;
-#pragma pack()
-
-// The full Mach message also includes a trailer.
-struct ExceptionRequest
-{
-    Request__mach_exception_raise_t body;
-    mach_msg_trailer_t trailer;
-};
-
-static bool
-HandleMachException(JSRuntime* rt, const ExceptionRequest& request)
-{
-    // Don't allow recursive handling of signals, see AutoSetHandlingSegFault.
-    if (rt->handlingSegFault)
-        return false;
-    AutoSetHandlingSegFault handling(rt);
-
-    // Get the port of the JSRuntime's thread from the message.
-    mach_port_t rtThread = request.body.thread.name;
-
-    // Read out the JSRuntime thread's register state.
-    EMULATOR_CONTEXT context;
-# if defined(JS_CPU_X64)
-    unsigned int thread_state_count = x86_THREAD_STATE64_COUNT;
-    unsigned int float_state_count = x86_FLOAT_STATE64_COUNT;
-    int thread_state = x86_THREAD_STATE64;
-    int float_state = x86_FLOAT_STATE64;
-# elif defined(JS_CPU_X86)
-    unsigned int thread_state_count = x86_THREAD_STATE_COUNT;
-    unsigned int float_state_count = x86_FLOAT_STATE_COUNT;
-    int thread_state = x86_THREAD_STATE;
-    int float_state = x86_FLOAT_STATE;
-# elif defined(JS_CPU_ARM)
-    unsigned int thread_state_count = ARM_THREAD_STATE_COUNT;
-    unsigned int float_state_count = ARM_NEON_STATE_COUNT;
-    int thread_state = ARM_THREAD_STATE;
-    int float_state = ARM_NEON_STATE;
-# else
-#  error Unsupported architecture
-# endif
-    kern_return_t kret;
-    kret = thread_get_state(rtThread, thread_state,
-                            (thread_state_t)&context.thread, &thread_state_count);
-    if (kret != KERN_SUCCESS)
-        return false;
-    kret = thread_get_state(rtThread, float_state,
-                            (thread_state_t)&context.float_, &float_state_count);
-    if (kret != KERN_SUCCESS)
-        return false;
-
-    uint8_t** ppc = ContextToPC(&context);
-    uint8_t* pc = *ppc;
-
-    if (request.body.exception != EXC_BAD_ACCESS || request.body.codeCnt != 2)
-        return false;
-
-    WasmActivation* activation = rt->wasmActivationStack();
-    if (!activation)
-        return false;
-
-    const Instance* instance = activation->compartment()->wasm.lookupInstanceDeprecated(pc);
-    if (!instance || !instance->codeSegment().containsFunctionPC(pc))
-        return false;
-
-    uint8_t* faultingAddress = reinterpret_cast<uint8_t*>(request.body.code[1]);
-
-    // This check isn't necessary, but, since we can, check anyway to make
-    // sure we aren't covering up a real bug.
-    if (!IsHeapAccessAddress(*instance, faultingAddress))
-        return false;
-
-    HandleMemoryAccess(&context, pc, faultingAddress, *instance, ppc);
-
-    // Update the thread state with the new pc and register values.
-    kret = thread_set_state(rtThread, float_state, (thread_state_t)&context.float_, float_state_count);
-    if (kret != KERN_SUCCESS)
-        return false;
-    kret = thread_set_state(rtThread, thread_state, (thread_state_t)&context.thread, thread_state_count);
-    if (kret != KERN_SUCCESS)
-        return false;
-
-    return true;
-}
-
-// Taken from mach_exc in /usr/include/mach/mach_exc.defs.
-static const mach_msg_id_t sExceptionId = 2405;
-
-// The choice of id here is arbitrary, the only constraint is that sQuitId != sExceptionId.
-static const mach_msg_id_t sQuitId = 42;
-
-static void
-MachExceptionHandlerThread(JSRuntime* rt)
-{
-    mach_port_t port = rt->wasmMachExceptionHandler.port();
-    kern_return_t kret;
-
-    while(true) {
-        ExceptionRequest request;
-        kret = mach_msg(&request.body.Head, MACH_RCV_MSG, 0, sizeof(request),
-                        port, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
-
-        // If we fail even receiving the message, we can't even send a reply!
-        // Rather than hanging the faulting thread (hanging the browser), crash.
-        if (kret != KERN_SUCCESS) {
-            fprintf(stderr, "MachExceptionHandlerThread: mach_msg failed with %d\n", (int)kret);
-            MOZ_CRASH();
-        }
-
-        // There are only two messages we should be receiving: an exception
-        // message that occurs when the runtime's thread faults and the quit
-        // message sent when the runtime is shutting down.
-        if (request.body.Head.msgh_id == sQuitId)
-            break;
-        if (request.body.Head.msgh_id != sExceptionId) {
-            fprintf(stderr, "Unexpected msg header id %d\n", (int)request.body.Head.msgh_bits);
-            MOZ_CRASH();
-        }
-
-        // Some thread just commited an EXC_BAD_ACCESS and has been suspended by
-        // the kernel. The kernel is waiting for us to reply with instructions.
-        // Our default is the "not handled" reply (by setting the RetCode field
-        // of the reply to KERN_FAILURE) which tells the kernel to continue
-        // searching at the process and system level. If this is an asm.js
-        // expected exception, we handle it and return KERN_SUCCESS.
-        bool handled = HandleMachException(rt, request);
-        kern_return_t replyCode = handled ? KERN_SUCCESS : KERN_FAILURE;
-
-        // This magic incantation to send a reply back to the kernel was derived
-        // from the exc_server generated by 'mig -v /usr/include/mach/mach_exc.defs'.
-        __Reply__exception_raise_t reply;
-        reply.Head.msgh_bits = MACH_MSGH_BITS(MACH_MSGH_BITS_REMOTE(request.body.Head.msgh_bits), 0);
-        reply.Head.msgh_size = sizeof(reply);
-        reply.Head.msgh_remote_port = request.body.Head.msgh_remote_port;
-        reply.Head.msgh_local_port = MACH_PORT_NULL;
-        reply.Head.msgh_id = request.body.Head.msgh_id + 100;
-        reply.NDR = NDR_record;
-        reply.RetCode = replyCode;
-        mach_msg(&reply.Head, MACH_SEND_MSG, sizeof(reply), 0, MACH_PORT_NULL,
-                 MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
-    }
-}
-
-MachExceptionHandler::MachExceptionHandler()
-  : installed_(false),
-    thread_(),
-    port_(MACH_PORT_NULL)
-{}
-
-void
-MachExceptionHandler::uninstall()
-{
-    if (installed_) {
-        thread_port_t thread = mach_thread_self();
-        kern_return_t kret = thread_set_exception_ports(thread,
-                                                        EXC_MASK_BAD_ACCESS,
-                                                        MACH_PORT_NULL,
-                                                        EXCEPTION_DEFAULT | MACH_EXCEPTION_CODES,
-                                                        THREAD_STATE_NONE);
-        mach_port_deallocate(mach_task_self(), thread);
-        if (kret != KERN_SUCCESS)
-            MOZ_CRASH();
-        installed_ = false;
-    }
-    if (thread_.joinable()) {
-        // Break the handler thread out of the mach_msg loop.
-        mach_msg_header_t msg;
-        msg.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
-        msg.msgh_size = sizeof(msg);
-        msg.msgh_remote_port = port_;
-        msg.msgh_local_port = MACH_PORT_NULL;
-        msg.msgh_reserved = 0;
-        msg.msgh_id = sQuitId;
-        kern_return_t kret = mach_msg(&msg, MACH_SEND_MSG, sizeof(msg), 0, MACH_PORT_NULL,
-                                      MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
-        if (kret != KERN_SUCCESS) {
-            fprintf(stderr, "MachExceptionHandler: failed to send quit message: %d\n", (int)kret);
-            MOZ_CRASH();
-        }
-
-        // Wait for the handler thread to complete before deallocating the port.
-        thread_.join();
-    }
-    if (port_ != MACH_PORT_NULL) {
-        DebugOnly<kern_return_t> kret = mach_port_destroy(mach_task_self(), port_);
-        MOZ_ASSERT(kret == KERN_SUCCESS);
-        port_ = MACH_PORT_NULL;
-    }
-}
-
-bool
-MachExceptionHandler::install(JSRuntime* rt)
-{
-    MOZ_ASSERT(!installed());
-    kern_return_t kret;
-    mach_port_t thread;
-
-    // Get a port which can send and receive data.
-    kret = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &port_);
-    if (kret != KERN_SUCCESS)
-        goto error;
-    kret = mach_port_insert_right(mach_task_self(), port_, port_, MACH_MSG_TYPE_MAKE_SEND);
-    if (kret != KERN_SUCCESS)
-        goto error;
-
-    // Create a thread to block on reading port_.
-    if (!thread_.init(MachExceptionHandlerThread, rt))
-        goto error;
-
-    // Direct exceptions on this thread to port_ (and thus our handler thread).
-    // Note: we are totally clobbering any existing *thread* exception ports and
-    // not even attempting to forward. Breakpad and gdb both use the *process*
-    // exception ports which are only called if the thread doesn't handle the
-    // exception, so we should be fine.
-    thread = mach_thread_self();
-    kret = thread_set_exception_ports(thread,
-                                      EXC_MASK_BAD_ACCESS,
-                                      port_,
-                                      EXCEPTION_DEFAULT | MACH_EXCEPTION_CODES,
-                                      THREAD_STATE_NONE);
-    mach_port_deallocate(mach_task_self(), thread);
-    if (kret != KERN_SUCCESS)
-        goto error;
-
-    installed_ = true;
-    return true;
-
-  error:
-    uninstall();
-    return false;
-}
-
-#else  // If not Windows or Mac, assume Unix
+#else  // If not Windows, assume Unix-like
 
 enum class Signal {
     SegFault,
@@ -1246,7 +896,7 @@ WasmFaultHandler(int signum, siginfo_t* info, void* context)
     else
         previousSignal->sa_handler(signum);
 }
-# endif // XP_WIN || XP_DARWIN || assume unix
+# endif // XP_WIN || assume Unix-like
 
 static void
 RedirectIonBackedgesToInterruptCheck(JSRuntime* rt)
@@ -1374,9 +1024,6 @@ ProcessHasSignalHandlers()
 # if defined(XP_WIN)
     if (!AddVectoredExceptionHandler(/* FirstHandler = */ true, WasmFaultHandler))
         return false;
-# elif defined(XP_DARWIN)
-    // OSX handles seg faults via the Mach exception handler above, so don't
-    // install WasmFaultHandler.
 # else
     // SA_NODEFER allows us to reenter the signal handler if we crash while
     // handling the signal, and fall through to the Breakpad handler by testing
@@ -1412,12 +1059,6 @@ wasm::EnsureSignalHandlers(JSRuntime* rt)
     if (!ProcessHasSignalHandlers())
         return true;
 
-#if defined(XP_DARWIN)
-    // On OSX, each JSRuntime gets its own handler thread.
-    if (!rt->wasmMachExceptionHandler.installed() && !rt->wasmMachExceptionHandler.install(rt))
-        return false;
-#endif
-
     return true;
 }
 
diff --git a/js/src/wasm/WasmSignalHandlers.h b/js/src/wasm/WasmSignalHandlers.h
index 87faa15025..7fe3dd86e6 100644
--- a/js/src/wasm/WasmSignalHandlers.h
+++ b/js/src/wasm/WasmSignalHandlers.h
@@ -1,6 +1,7 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  *
  * Copyright 2014 Mozilla Foundation
+ * Copyright 2021 Moonchild Productions
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,10 +20,6 @@
 #define wasm_signal_handlers_h
 
 #include "mozilla/Attributes.h"
-
-#if defined(XP_DARWIN)
-# include <mach/mach.h>
-#endif
 #include "threading/Thread.h"
 
 struct JSRuntime;
@@ -46,30 +43,6 @@ EnsureSignalHandlers(JSRuntime* rt);
 bool
 HaveSignalHandlers();
 
-#if defined(XP_DARWIN)
-// On OSX we are forced to use the lower-level Mach exception mechanism instead
-// of Unix signals. Mach exceptions are not handled on the victim's stack but
-// rather require an extra thread. For simplicity, we create one such thread
-// per JSRuntime (upon the first use of asm.js in the JSRuntime). This thread
-// and related resources are owned by AsmJSMachExceptionHandler which is owned
-// by JSRuntime.
-class MachExceptionHandler
-{
-    bool installed_;
-    js::Thread thread_;
-    mach_port_t port_;
-
-    void uninstall();
-
-  public:
-    MachExceptionHandler();
-    ~MachExceptionHandler() { uninstall(); }
-    mach_port_t port() const { return port_; }
-    bool installed() const { return installed_; }
-    bool install(JSRuntime* rt);
-};
-#endif
-
 // Test whether the given PC is within the innermost wasm activation. Return
 // false if it is not, or it cannot be determined.
 bool IsPCInWasmCode(void *pc);