Revert of [wasm] Initial signal handler

src/trap-handler/trap-handler.h

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_TRAP_HANDLER_H_
 #define V8_TRAP_HANDLER_H_
 
-#include <signal.h>
-#include <stdint.h>
-#include <stdlib.h>
-
-#include "src/base/build_config.h"
-#include "src/flags.h"
-#include "src/globals.h"
-
-#if V8_OS_LINUX
-#include <ucontext.h>
-#endif
-
 namespace v8 {
 namespace internal {
 namespace trap_handler {
 
-// TODO(eholk): Support trap handlers on other platforms.
-#if V8_TARGET_ARCH_X64 && V8_OS_LINUX
-#define V8_TRAP_HANDLER_SUPPORTED 1
-#else
-#define V8_TRAP_HANDLER_SUPPORTED 0
-#endif
-
 struct ProtectedInstructionData {
   // The offset of this instruction from the start of its code object.
   intptr_t instr_offset;
 
   // The offset of the landing pad from the start of its code object.
   //
   // TODO(eholk): Using a single landing pad and store parameters here.
   intptr_t landing_offset;
 };
 
-/// Adjusts the base code pointer.
-void UpdateHandlerDataCodePointer(int index, void* base);
-
-/// Adds the handler data to the place where the signal handler will find it.
-///
-/// This returns a number that can be used to identify the handler data to
-/// UpdateHandlerDataCodePointer and ReleaseHandlerData, or -1 on failure.
-int RegisterHandlerData(void* base, size_t size,
-                        size_t num_protected_instructions,
-                        ProtectedInstructionData* protected_instructions);
-
-/// Removes the data from the master list and frees any memory, if necessary.
-void ReleaseHandlerData(int index);
-
-#if V8_OS_WIN
-#define THREAD_LOCAL __declspec(thread)
-#elif V8_OS_ANDROID
-// TODO(eholk): fix this before enabling for trap handlers for Android.
-#define THREAD_LOCAL
-#else
-#define THREAD_LOCAL __thread
-#endif
-
-inline bool UseTrapHandler() {
-  return FLAG_wasm_trap_handler && V8_TRAP_HANDLER_SUPPORTED;
-}
-
-extern THREAD_LOCAL bool g_thread_in_wasm_code;
-
-inline bool IsThreadInWasm() { return g_thread_in_wasm_code; }
-
-inline void SetThreadInWasm() {
-  if (UseTrapHandler()) {
-    DCHECK(!IsThreadInWasm());
-    g_thread_in_wasm_code = true;
-  }
-}
-inline void ClearThreadInWasm() {
-  if (UseTrapHandler()) {
-    DCHECK(IsThreadInWasm());
-    g_thread_in_wasm_code = false;
-  }
-}
-
-bool RegisterDefaultSignalHandler();
-
-#if V8_OS_LINUX
-bool TryHandleSignal(int signum, siginfo_t* info, ucontext_t* context);
-#endif  // V8_OS_LINUX
-
 }  // namespace trap_handler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TRAP_HANDLER_H_