From 05771279affce857e9b4d684f9afe77606b30f35 Mon Sep 17 00:00:00 2001
From: Gus Caplan <me@gus.host>
Date: Thu, 3 Sep 2020 10:28:18 -0500
Subject: [PATCH] src: enable wasm trap handler on windows
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

PR-URL: https://github.com/nodejs/node/pull/35033
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Shelley Vohr <codebytere@gmail.com>
---
 src/node.cc | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/node.cc b/src/node.cc
index dd2cd0db75dc8a..00cce0fd465541 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -69,15 +69,19 @@
 
 #include "large_pages/node_large_page.h"
 
-#if defined(__APPLE__) || defined(__linux__)
+#if defined(__APPLE__) || defined(__linux__) || defined(_WIN32)
 #define NODE_USE_V8_WASM_TRAP_HANDLER 1
 #else
 #define NODE_USE_V8_WASM_TRAP_HANDLER 0
 #endif
 
 #if NODE_USE_V8_WASM_TRAP_HANDLER
+#if defined(_WIN32)
+#include "v8-wasm-trap-handler-win.h"
+#else
 #include <atomic>
 #include "v8-wasm-trap-handler-posix.h"
+#endif
 #endif  // NODE_USE_V8_WASM_TRAP_HANDLER
 
 // ========== global C headers ==========
@@ -149,6 +153,10 @@ bool v8_initialized = false;
 // process-relative uptime base in nanoseconds, initialized in node::Start()
 uint64_t node_start_time;
 
+#if NODE_USE_V8_WASM_TRAP_HANDLER && defined(_WIN32)
+PVOID old_vectored_exception_handler;
+#endif
+
 // node_v8_platform-inl.h
 struct V8Platform v8_platform;
 }  // namespace per_process
@@ -506,6 +514,14 @@ MaybeLocal<Value> StartExecution(Environment* env, StartExecutionCallback cb) {
 typedef void (*sigaction_cb)(int signo, siginfo_t* info, void* ucontext);
 #endif
 #if NODE_USE_V8_WASM_TRAP_HANDLER
+#if defined(_WIN32)
+static LONG TrapWebAssemblyOrContinue(EXCEPTION_POINTERS* exception) {
+  if (v8::TryHandleWebAssemblyTrapWindows(exception)) {
+    return EXCEPTION_CONTINUE_EXECUTION;
+  }
+  return EXCEPTION_CONTINUE_SEARCH;
+}
+#else
 static std::atomic<sigaction_cb> previous_sigsegv_action;
 
 void TrapWebAssemblyOrContinue(int signo, siginfo_t* info, void* ucontext) {
@@ -525,6 +541,7 @@ void TrapWebAssemblyOrContinue(int signo, siginfo_t* info, void* ucontext) {
     }
   }
 }
+#endif  // defined(_WIN32)
 #endif  // NODE_USE_V8_WASM_TRAP_HANDLER
 
 #ifdef __POSIX__
@@ -547,7 +564,6 @@ void RegisterSignalHandler(int signal,
   sigfillset(&sa.sa_mask);
   CHECK_EQ(sigaction(signal, &sa, nullptr), 0);
 }
-
 #endif  // __POSIX__
 
 #ifdef __POSIX__
@@ -630,6 +646,13 @@ inline void PlatformInit() {
   RegisterSignalHandler(SIGTERM, SignalExit, true);
 
 #if NODE_USE_V8_WASM_TRAP_HANDLER
+#if defined(_WIN32)
+  {
+    constexpr ULONG first = TRUE;
+    per_process::old_vectored_exception_handler =
+        AddVectoredExceptionHandler(first, TrapWebAssemblyOrContinue);
+  }
+#else
   // Tell V8 to disable emitting WebAssembly
   // memory bounds checks. This means that we have
   // to catch the SIGSEGV in TrapWebAssemblyOrContinue
@@ -640,6 +663,7 @@ inline void PlatformInit() {
     sa.sa_sigaction = TrapWebAssemblyOrContinue;
     CHECK_EQ(sigaction(SIGSEGV, &sa, nullptr), 0);
   }
+#endif  // defined(_WIN32)
   V8::EnableWebAssemblyTrapHandler(false);
 #endif  // NODE_USE_V8_WASM_TRAP_HANDLER
 
@@ -1050,6 +1074,10 @@ void TearDownOncePerProcess() {
   per_process::v8_initialized = false;
   V8::Dispose();
 
+#if NODE_USE_V8_WASM_TRAP_HANDLER && defined(_WIN32)
+  RemoveVectoredExceptionHandler(per_process::old_vectored_exception_handler);
+#endif
+
   // uv_run cannot be called from the time before the beforeExit callback
   // runs until the program exits unless the event loop has any referenced
   // handles after beforeExit terminates. This prevents unrefed timers