deps: update V8 to 6.4.388.40

PR-URL: https://github.com/nodejs/node/pull/17489
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>

5 files changed, 41 insertions, 15 deletions

diff --git a/deps/v8/src/trap-handler/handler-inside.cc b/deps/v8/src/trap-handler/handler-inside.cc
index 9336636b21..d3c543f4f4 100644
--- a/deps/v8/src/trap-handler/handler-inside.cc
+++ b/deps/v8/src/trap-handler/handler-inside.cc
@@ -102,13 +102,15 @@ bool TryHandleSignal(int signum, siginfo_t* info, ucontext_t* context) {
     if (TryFindLandingPad(fault_addr, &landing_pad)) {
       // Tell the caller to return to the landing pad.
       context->uc_mcontext.gregs[REG_RIP] = landing_pad;
+      // We will return to wasm code, so restore the g_thread_in_wasm_code flag.
+      g_thread_in_wasm_code = true;
       return true;
     }
   }  // end signal mask scope
 
   // If we get here, it's not a recoverable wasm fault, so we go to the next
-  // handler.
-  g_thread_in_wasm_code = true;
+  // handler. Leave the g_thread_in_wasm_code flag unset since we do not return
+  // to wasm code.
   return false;
 }
 
@@ -160,18 +162,14 @@ void HandleSignal(int signum, siginfo_t* info, void* context) {
 
   if (!TryHandleSignal(signum, info, uc)) {
     // Since V8 didn't handle this signal, we want to re-raise the same signal.
-    // For kernel-generated SEGV signals, we do this by restoring the default
+    // For kernel-generated SEGV signals, we do this by restoring the original
     // SEGV handler and then returning. The fault will happen again and the
     // usual SEGV handling will happen.
     //
     // We handle user-generated signals by calling raise() instead. This is for
     // completeness. We should never actually see one of these, but just in
     // case, we do the right thing.
-    struct sigaction action;
-    action.sa_handler = SIG_DFL;
-    sigemptyset(&action.sa_mask);
-    action.sa_flags = 0;
-    sigaction(signum, &action, nullptr);
+    RestoreOriginalSignalHandler();
     if (!IsKernelGeneratedSignal(info)) {
       raise(signum);
     }
diff --git a/deps/v8/src/trap-handler/handler-outside.cc b/deps/v8/src/trap-handler/handler-outside.cc
index 5cb9661e7b..2c9225d485 100644
--- a/deps/v8/src/trap-handler/handler-outside.cc
+++ b/deps/v8/src/trap-handler/handler-outside.cc
@@ -115,7 +115,7 @@ void ValidateCodeObjects() {
 
 CodeProtectionInfo* CreateHandlerData(
     void* base, size_t size, size_t num_protected_instructions,
-    ProtectedInstructionData* protected_instructions) {
+    const ProtectedInstructionData* protected_instructions) {
   const size_t alloc_size = HandlerDataSize(num_protected_instructions);
   CodeProtectionInfo* data =
       reinterpret_cast<CodeProtectionInfo*>(malloc(alloc_size));
@@ -143,9 +143,9 @@ void UpdateHandlerDataCodePointer(int index, void* base) {
   data->base = base;
 }
 
-int RegisterHandlerData(void* base, size_t size,
-                        size_t num_protected_instructions,
-                        ProtectedInstructionData* protected_instructions) {
+int RegisterHandlerData(
+    void* base, size_t size, size_t num_protected_instructions,
+    const ProtectedInstructionData* protected_instructions) {
   // TODO(eholk): in debug builds, make sure this data isn't already registered.
 
   CodeProtectionInfo* data = CreateHandlerData(
@@ -248,6 +248,8 @@ void ReleaseHandlerData(int index) {
 
 bool RegisterDefaultSignalHandler() {
 #if V8_TRAP_HANDLER_SUPPORTED
+  CHECK(!g_is_default_signal_handler_registered);
+
   struct sigaction action;
   action.sa_sigaction = HandleSignal;
   action.sa_flags = SA_SIGINFO;
@@ -255,10 +257,11 @@ bool RegisterDefaultSignalHandler() {
   // {sigaction} installs a new custom segfault handler. On success, it returns
   // 0. If we get a nonzero value, we report an error to the caller by returning
   // false.
-  if (sigaction(SIGSEGV, &action, nullptr) != 0) {
+  if (sigaction(SIGSEGV, &action, &g_old_handler) != 0) {
     return false;
   }
 
+  g_is_default_signal_handler_registered = true;
   return true;
 #else
   return false;
diff --git a/deps/v8/src/trap-handler/handler-shared.cc b/deps/v8/src/trap-handler/handler-shared.cc
index 19f8b5bf68..d07f7ae131 100644
--- a/deps/v8/src/trap-handler/handler-shared.cc
+++ b/deps/v8/src/trap-handler/handler-shared.cc
@@ -26,7 +26,22 @@ namespace trap_handler {
 // We declare this as int rather than bool as a workaround for a glibc bug, in
 // which the dynamic loader cannot handle executables whose TLS area is only
 // 1 byte in size; see https://sourceware.org/bugzilla/show_bug.cgi?id=14898.
-THREAD_LOCAL int g_thread_in_wasm_code = false;
+THREAD_LOCAL int g_thread_in_wasm_code;
+
+#if V8_TRAP_HANDLER_SUPPORTED
+// When using the default signal handler, we save the old one to restore in case
+// V8 chooses not to handle the signal.
+struct sigaction g_old_handler;
+bool g_is_default_signal_handler_registered;
+#endif
+
+V8_EXPORT_PRIVATE void RestoreOriginalSignalHandler() {
+#if V8_TRAP_HANDLER_SUPPORTED
+  if (sigaction(SIGSEGV, &g_old_handler, nullptr) == 0) {
+    g_is_default_signal_handler_registered = false;
+  }
+#endif
+}
 
 static_assert(sizeof(g_thread_in_wasm_code) > 1,
               "sizeof(thread_local_var) must be > 1, see "
diff --git a/deps/v8/src/trap-handler/trap-handler-internal.h b/deps/v8/src/trap-handler/trap-handler-internal.h
index 7897bd0ecc..1476eb844b 100644
--- a/deps/v8/src/trap-handler/trap-handler-internal.h
+++ b/deps/v8/src/trap-handler/trap-handler-internal.h
@@ -68,6 +68,13 @@ extern std::atomic_size_t gRecoveredTrapCount;
 // unchanged.
 bool TryFindLandingPad(uintptr_t fault_addr, uintptr_t* landing_pad);
 
+#if V8_TRAP_HANDLER_SUPPORTED
+// When using the default signal handler, we save the old one to restore in case
+// V8 chooses not to handle the signal.
+extern struct sigaction g_old_handler;
+extern bool g_is_default_signal_handler_registered;
+#endif
+
 }  // namespace trap_handler
 }  // namespace internal
 }  // namespace v8
diff --git a/deps/v8/src/trap-handler/trap-handler.h b/deps/v8/src/trap-handler/trap-handler.h
index 7189c27e29..612cf51b45 100644
--- a/deps/v8/src/trap-handler/trap-handler.h
+++ b/deps/v8/src/trap-handler/trap-handler.h
@@ -50,9 +50,11 @@ void UpdateHandlerDataCodePointer(int index, void* base);
 /// UpdateHandlerDataCodePointer and ReleaseHandlerData, or -1 on failure.
 int RegisterHandlerData(void* base, size_t size,
                         size_t num_protected_instructions,
-                        ProtectedInstructionData* protected_instructions);
+                        const ProtectedInstructionData* protected_instructions);
 
 /// Removes the data from the master list and frees any memory, if necessary.
+/// TODO(mtrofin): once FLAG_wasm_jit_to_native is not needed, we can switch
+/// to using size_t for index and not need kInvalidIndex.
 void ReleaseHandlerData(int index);
 
 #if V8_OS_WIN
@@ -87,6 +89,7 @@ inline void ClearThreadInWasm() {
 }
 
 bool RegisterDefaultSignalHandler();
+V8_EXPORT_PRIVATE void RestoreOriginalSignalHandler();
 
 #if V8_OS_LINUX
 bool TryHandleSignal(int signum, siginfo_t* info, ucontext_t* context);