[vm] Give the native call wrappers C linkage.

This avoids undefined behavior.

Cf. 18aa7d3678

TEST=ci
Change-Id: I2dd82517177ee812b3cd3ae4b1c748de129ec665
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/432720
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

runtime/vm/native_entry.cc

@@ -111,9 +111,14 @@ void NativeEntry::MaybePropagateError(NativeArguments* arguments) {
   }
 }
 
+extern "C" void DRT_BootstrapNativeCall(Dart_NativeArguments args,
+                                        Dart_NativeFunction func) {
+  CHECK_STACK_ALIGNMENT;
+  NativeEntry::BootstrapNativeCallWrapper(args, func);
+}
+
 uword NativeEntry::BootstrapNativeCallWrapperEntry() {
-  uword entry =
-      reinterpret_cast<uword>(NativeEntry::BootstrapNativeCallWrapper);
+  uword entry = reinterpret_cast<uword>(DRT_BootstrapNativeCall);
 #if defined(USING_SIMULATOR)
   entry = Simulator::RedirectExternalReference(
       entry, Simulator::kNativeCallWrapper,
@@ -124,7 +129,6 @@ uword NativeEntry::BootstrapNativeCallWrapperEntry() {
 
 void NativeEntry::BootstrapNativeCallWrapper(Dart_NativeArguments args,
                                              Dart_NativeFunction func) {
-  CHECK_STACK_ALIGNMENT;
   if (func == LinkNativeCall) {
     func(args);
     return;
@@ -151,8 +155,14 @@ void NativeEntry::BootstrapNativeCallWrapper(Dart_NativeArguments args,
   }
 }
 
+extern "C" void DRT_NoScopeNativeCall(Dart_NativeArguments args,
+                                      Dart_NativeFunction func) {
+  CHECK_STACK_ALIGNMENT;
+  NativeEntry::NoScopeNativeCallWrapper(args, func);
+}
+
 uword NativeEntry::NoScopeNativeCallWrapperEntry() {
-  uword entry = reinterpret_cast<uword>(NativeEntry::NoScopeNativeCallWrapper);
+  uword entry = reinterpret_cast<uword>(DRT_NoScopeNativeCall);
 #if defined(USING_SIMULATOR)
   entry = Simulator::RedirectExternalReference(
       entry, Simulator::kNativeCallWrapper,
@@ -163,13 +173,6 @@ uword NativeEntry::NoScopeNativeCallWrapperEntry() {
 
 void NativeEntry::NoScopeNativeCallWrapper(Dart_NativeArguments args,
                                            Dart_NativeFunction func) {
-  CHECK_STACK_ALIGNMENT;
-  NoScopeNativeCallWrapperNoStackCheck(args, func);
-}
-
-void NativeEntry::NoScopeNativeCallWrapperNoStackCheck(
-    Dart_NativeArguments args,
-    Dart_NativeFunction func) {
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   // Tell MemorySanitizer 'arguments' is initialized by generated code.
   MSAN_UNPOISON(arguments, sizeof(*arguments));
@@ -183,9 +186,14 @@ void NativeEntry::NoScopeNativeCallWrapperNoStackCheck(
   ASSERT(thread->execution_state() == Thread::kThreadInGenerated);
 }
 
+extern "C" void DRT_AutoScopeNativeCall(Dart_NativeArguments args,
+                                        Dart_NativeFunction func) {
+  CHECK_STACK_ALIGNMENT;
+  NativeEntry::AutoScopeNativeCallWrapper(args, func);
+}
+
 uword NativeEntry::AutoScopeNativeCallWrapperEntry() {
-  uword entry =
-      reinterpret_cast<uword>(NativeEntry::AutoScopeNativeCallWrapper);
+  uword entry = reinterpret_cast<uword>(DRT_AutoScopeNativeCall);
 #if defined(USING_SIMULATOR)
   entry = Simulator::RedirectExternalReference(
       entry, Simulator::kNativeCallWrapper,
@@ -196,13 +204,6 @@ uword NativeEntry::AutoScopeNativeCallWrapperEntry() {
 
 void NativeEntry::AutoScopeNativeCallWrapper(Dart_NativeArguments args,
                                              Dart_NativeFunction func) {
-  CHECK_STACK_ALIGNMENT;
-  AutoScopeNativeCallWrapperNoStackCheck(args, func);
-}
-
-void NativeEntry::AutoScopeNativeCallWrapperNoStackCheck(
-    Dart_NativeArguments args,
-    Dart_NativeFunction func) {
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   // Tell MemorySanitizer 'arguments' is initialized by generated code.
   MSAN_UNPOISON(arguments, sizeof(*arguments));
@@ -249,8 +250,9 @@ static NativeFunction ResolveNativeFunction(Zone* zone,
 }
 
 uword NativeEntry::LinkNativeCallEntry() {
-  uword entry = reinterpret_cast<uword>(NativeEntry::LinkNativeCall);
-  return entry;
+  // This one does not need a simulator redirect because it is always called
+  // through BootstrapNativeCallWrapper, not directly from generated code.
+  return reinterpret_cast<uword>(NativeEntry::LinkNativeCall);
 }
 
 void NativeEntry::LinkNativeCall(Dart_NativeArguments args) {
@@ -322,14 +324,10 @@ void NativeEntry::LinkNativeCall(Dart_NativeArguments args) {
     NativeEntry::BootstrapNativeCallWrapper(
         args, reinterpret_cast<Dart_NativeFunction>(target_function));
   } else if (is_auto_scope) {
-    // Because this call is within a compilation unit, Clang doesn't respect
-    // the ABI alignment here.
-    NativeEntry::AutoScopeNativeCallWrapperNoStackCheck(
+    NativeEntry::AutoScopeNativeCallWrapper(
         args, reinterpret_cast<Dart_NativeFunction>(target_function));
   } else {
-    // Because this call is within a compilation unit, Clang doesn't respect
-    // the ABI alignment here.
-    NativeEntry::NoScopeNativeCallWrapperNoStackCheck(
+    NativeEntry::NoScopeNativeCallWrapper(
         args, reinterpret_cast<Dart_NativeFunction>(target_function));
   }
 }

runtime/vm/native_entry.h

@@ -118,11 +118,6 @@ class NativeEntry : public AllStatic {
   static void LinkNativeCall(Dart_NativeArguments args);
 
  private:
-  static void NoScopeNativeCallWrapperNoStackCheck(Dart_NativeArguments args,
-                                                   Dart_NativeFunction func);
-  static void AutoScopeNativeCallWrapperNoStackCheck(Dart_NativeArguments args,
-                                                     Dart_NativeFunction func);
-
   static void MaybePropagateError(NativeArguments* arguments);
 };