Set VMTag from stubs when transitioning between Dart and Native

runtime/vm/stub_code_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/heap.h"
 #include "vm/instructions.h"
 #include "vm/object_store.h"
 #include "vm/resolver.h"
 #include "vm/scavenger.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
-
+#include "vm/tags.h"
 
 #define __ assembler->
 
 namespace dart {
 
 DEFINE_FLAG(bool, inline_alloc, true, "Inline allocation of objects.");
 DEFINE_FLAG(bool, use_slow_path, false,
     "Set to true for debugging & verifying the slow paths.");
 DECLARE_FLAG(bool, trace_optimized_ic_calls);
 
@@ skipping 21 matching lines @@
   // Save exit frame information to enable stack walking as we are about
   // to transition to Dart VM C++ code.
   __ movq(Address(RAX, Isolate::top_exit_frame_info_offset()), RSP);
 
   // Save current Context pointer into Isolate structure.
   __ movq(Address(RAX, Isolate::top_context_offset()), CTX);
 
   // Cache Isolate pointer into CTX while executing runtime code.
   __ movq(CTX, RAX);
 
+#if defined(DEBUG)
+  { Label ok;
+    // Check that we are always entering from Dart code.
+    __ movq(RAX, Immediate(VMTag::kScriptTagId));
+    __ cmpq(RAX, Address(CTX, Isolate::vm_tag_offset()));
+    __ j(EQUAL, &ok, Assembler::kNearJump);
+    __ Stop("Not coming from Dart code.");
+    __ Bind(&ok);
+  }
+#endif
+
+  // Mark that the isolate is executing VM code.
+  __ movq(Address(CTX, Isolate::vm_tag_offset()), Immediate(VMTag::kVMTagId));
+
   // Reserve space for arguments and align frame before entering C++ world.
   __ subq(RSP, Immediate(sizeof(NativeArguments)));
   if (OS::ActivationFrameAlignment() > 1) {
     __ andq(RSP, Immediate(~(OS::ActivationFrameAlignment() - 1)));
   }
 
   // Pass NativeArguments structure by value and call runtime.
   __ movq(Address(RSP, isolate_offset), CTX);  // Set isolate in NativeArgs.
   // There are no runtime calls to closures, so we do not need to set the tag
   // bits kClosureFunctionBit and kInstanceFunctionBit in argc_tag_.
   __ movq(Address(RSP, argc_tag_offset), R10);  // Set argc in NativeArguments.
   __ leaq(RAX, Address(RBP, R10, TIMES_8, 1 * kWordSize));  // Compute argv.
   __ movq(Address(RSP, argv_offset), RAX);  // Set argv in NativeArguments.
   __ addq(RAX, Immediate(1 * kWordSize));  // Retval is next to 1st argument.
   __ movq(Address(RSP, retval_offset), RAX);  // Set retval in NativeArguments.
   __ call(RBX);
 
+  // Mark that the isolate is executing Dart code.
+  __ movq(Address(CTX, Isolate::vm_tag_offset()),
+          Immediate(VMTag::kScriptTagId));
+
   // Reset exit frame information in Isolate structure.
   __ movq(Address(CTX, Isolate::top_exit_frame_info_offset()), Immediate(0));
 
   // Load Context pointer from Isolate structure into RBX.
   __ movq(RBX, Address(CTX, Isolate::top_context_offset()));
 
   // Reset Context pointer in Isolate structure.
   __ LoadObject(R12, Object::null_object(), PP);
   __ movq(Address(CTX, Isolate::top_context_offset()), R12);
 
@@ skipping 44 matching lines @@
 
   __ EnterFrame(0);
 
   // Load current Isolate pointer from Context structure into R8.
   __ movq(R8, FieldAddress(CTX, Context::isolate_offset()));
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to native code.
   __ movq(Address(R8, Isolate::top_exit_frame_info_offset()), RSP);
 
-  // Save current Context pointer into Isolate structure.
+// Save current Context pointer into Isolate structure.
   __ movq(Address(R8, Isolate::top_context_offset()), CTX);
 
   // Cache Isolate pointer into CTX while executing native code.
   __ movq(CTX, R8);
 
+#if defined(DEBUG)
+  { Label ok;
+    // Check that we are always entering from Dart code.
+    __ movq(R8, Immediate(VMTag::kScriptTagId));
+    __ cmpq(R8, Address(CTX, Isolate::vm_tag_offset()));
+    __ j(EQUAL, &ok, Assembler::kNearJump);
+    __ Stop("Not coming from Dart code.");
+    __ Bind(&ok);
+  }
+#endif
+
+  // Mark that the isolate is executing Native code.
+  __ movq(Address(CTX, Isolate::vm_tag_offset()),
+          Immediate(VMTag::kRuntimeNativeTagId));
+
   // Reserve space for the native arguments structure passed on the stack (the
   // outgoing pointer parameter to the native arguments structure is passed in
   // RDI) and align frame before entering the C++ world.
   __ subq(RSP, Immediate(sizeof(NativeArguments)));
   if (OS::ActivationFrameAlignment() > 1) {
     __ andq(RSP, Immediate(~(OS::ActivationFrameAlignment() - 1)));
   }
 
   // Pass NativeArguments structure by value and call native function.
   __ movq(Address(RSP, isolate_offset), CTX);  // Set isolate in NativeArgs.
   __ movq(Address(RSP, argc_tag_offset), R10);  // Set argc in NativeArguments.
   __ movq(Address(RSP, argv_offset), RAX);  // Set argv in NativeArguments.
   __ leaq(RAX, Address(RBP, 2 * kWordSize));  // Compute return value addr.
   __ movq(Address(RSP, retval_offset), RAX);  // Set retval in NativeArguments.
   __ movq(RDI, RSP);  // Pass the pointer to the NativeArguments.
 
   // Call native function (setsup scope if not leaf function).
   Label leaf_call;
   Label done;
   __ testq(R10, Immediate(NativeArguments::AutoSetupScopeMask()));
   __ j(ZERO, &leaf_call);
   __ movq(RSI, RBX);  // Pass pointer to function entrypoint.
   __ call(&NativeEntry::NativeCallWrapperLabel());
   __ jmp(&done);
   __ Bind(&leaf_call);
   __ call(RBX);
   __ Bind(&done);
 
+  // Mark that the isolate is executing Dart code.
+  __ movq(Address(CTX, Isolate::vm_tag_offset()),
+          Immediate(VMTag::kScriptTagId));
+
   // Reset exit frame information in Isolate structure.
   __ movq(Address(CTX, Isolate::top_exit_frame_info_offset()), Immediate(0));
 
   // Load Context pointer from Isolate structure into R8.
   __ movq(R8, Address(CTX, Isolate::top_context_offset()));
 
   // Reset Context pointer in Isolate structure.
   __ LoadObject(R12, Object::null_object(), PP);
   __ movq(Address(CTX, Isolate::top_context_offset()), R12);
 
@@ skipping 30 matching lines @@
   // Save exit frame information to enable stack walking as we are about
   // to transition to native code.
   __ movq(Address(R8, Isolate::top_exit_frame_info_offset()), RSP);
 
   // Save current Context pointer into Isolate structure.
   __ movq(Address(R8, Isolate::top_context_offset()), CTX);
 
   // Cache Isolate pointer into CTX while executing native code.
   __ movq(CTX, R8);
 
+#if defined(DEBUG)
+  { Label ok;
+    // Check that we are always entering from Dart code.
+    __ movq(R8, Immediate(VMTag::kScriptTagId));
+    __ cmpq(R8, Address(CTX, Isolate::vm_tag_offset()));
+    __ j(EQUAL, &ok, Assembler::kNearJump);
+    __ Stop("Not coming from Dart code.");
+    __ Bind(&ok);
+  }
+#endif
+
+  // Mark that the isolate is executing Native code.
+  __ movq(Address(CTX, Isolate::vm_tag_offset()),
+          Immediate(VMTag::kRuntimeNativeTagId));
+
   // Reserve space for the native arguments structure passed on the stack (the
   // outgoing pointer parameter to the native arguments structure is passed in
   // RDI) and align frame before entering the C++ world.
   __ subq(RSP, Immediate(sizeof(NativeArguments)));
   if (OS::ActivationFrameAlignment() > 1) {
     __ andq(RSP, Immediate(~(OS::ActivationFrameAlignment() - 1)));
   }
 
   // Pass NativeArguments structure by value and call native function.
   __ movq(Address(RSP, isolate_offset), CTX);  // Set isolate in NativeArgs.
   __ movq(Address(RSP, argc_tag_offset), R10);  // Set argc in NativeArguments.
   __ movq(Address(RSP, argv_offset), RAX);  // Set argv in NativeArguments.
   __ leaq(RAX, Address(RBP, 2 * kWordSize));  // Compute return value addr.
   __ movq(Address(RSP, retval_offset), RAX);  // Set retval in NativeArguments.
   __ movq(RDI, RSP);  // Pass the pointer to the NativeArguments.
   __ call(RBX);
 
+  // Mark that the isolate is executing Dart code.
+  __ movq(Address(CTX, Isolate::vm_tag_offset()),
+          Immediate(VMTag::kScriptTagId));
+
   // Reset exit frame information in Isolate structure.
   __ movq(Address(CTX, Isolate::top_exit_frame_info_offset()), Immediate(0));
 
   // Load Context pointer from Isolate structure into R8.
   __ movq(R8, Address(CTX, Isolate::top_context_offset()));
 
   // Reset Context pointer in Isolate structure.
   __ LoadObject(R12, Object::null_object(), PP);
   __ movq(Address(CTX, Isolate::top_context_offset()), R12);
 
@@ skipping 559 matching lines @@
   // available in generated code and calls to Isolate::Current() need not be
   // done. The assumption is that this register will never be clobbered by
   // compiled or runtime stub code.
 
   // Cache the new Context pointer into CTX while executing Dart code.
   __ movq(CTX, Address(RCX, VMHandles::kOffsetOfRawPtrInHandle));
 
   // Load Isolate pointer from Context structure into R8.
   __ movq(R8, FieldAddress(CTX, Context::isolate_offset()));
 
+  // Save the current VMTag on the stack.
+  ASSERT(kSavedVMTagSlotFromEntryFp == -8);
+  __ movq(RAX, Address(R8, Isolate::vm_tag_offset()));
+  __ pushq(RAX);
+
+  // Mark that the isolate is executing Dart code.
+  __ movq(Address(R8, Isolate::vm_tag_offset()),
+          Immediate(VMTag::kScriptTagId));
+
   // Save the top exit frame info. Use RAX as a temporary register.
   // StackFrameIterator reads the top exit frame info saved in this frame.
   // The constant kExitLinkSlotFromEntryFp must be kept in sync with the
   // code below.
-  ASSERT(kExitLinkSlotFromEntryFp == -8);
+  ASSERT(kExitLinkSlotFromEntryFp == -9);
   __ movq(RAX, Address(R8, Isolate::top_exit_frame_info_offset()));
   __ pushq(RAX);
   __ movq(Address(R8, Isolate::top_exit_frame_info_offset()), Immediate(0));
 
   // Save the old Context pointer. Use RAX as a temporary register.
   // Note that VisitObjectPointers will find this saved Context pointer during
   // GC marking, since it traverses any information between SP and
   // FP - kExitLinkSlotFromEntryFp * kWordSize.
   // EntryFrame::SavedContext reads the context saved in this frame.
   // The constant kSavedContextSlotFromEntryFp must be kept in sync with
   // the code below.
-  ASSERT(kSavedContextSlotFromEntryFp == -9);
+  ASSERT(kSavedContextSlotFromEntryFp == -10);
   __ movq(RAX, Address(R8, Isolate::top_context_offset()));
   __ pushq(RAX);
 
   // Load arguments descriptor array into R10, which is passed to Dart code.
   __ movq(R10, Address(RSI, VMHandles::kOffsetOfRawPtrInHandle));
 
   // Load number of arguments into RBX.
   __ movq(RBX, FieldAddress(R10, ArgumentsDescriptor::count_offset()));
   __ SmiUntag(RBX);
 
@@ skipping 36 matching lines @@
   // Restore the saved Context pointer into the Isolate structure.
   // Uses RCX as a temporary register for this.
   __ popq(RCX);
   __ movq(Address(CTX, Isolate::top_context_offset()), RCX);
 
   // Restore the saved top exit frame info back into the Isolate structure.
   // Uses RDX as a temporary register for this.
   __ popq(RDX);
   __ movq(Address(CTX, Isolate::top_exit_frame_info_offset()), RDX);
 
+  // Restore the current VMTag from the stack.
+  __ popq(RDX);
+  __ movq(Address(CTX, Isolate::vm_tag_offset()), RDX);
+
   // Restore C++ ABI callee-saved registers.
   __ popq(R15);
   __ popq(R14);
   __ popq(R13);
   __ popq(R12);
   __ popq(RBX);
 
   // Restore the frame pointer.
   __ LeaveFrame();
 
@@ skipping 1035 matching lines @@
 
   __ movq(left, Address(RSP, 2 * kWordSize));
   __ movq(right, Address(RSP, 1 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64