We can throw an exception but we cannot deoptimize at a runtime call.

runtime/vm/flow_graph_compiler_x64.cc

 // Copyright (c) 2012, 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"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "lib/error.h"
@@ skipping 433 matching lines @@
 // - NULL -> return false.
 // - Smi -> compile time subtype check (only if dst class is not parameterized).
 // - Class equality (only if class is not parameterized).
 // Inputs:
 // - RAX: object.
 // - RDX: instantiator type arguments or raw_null.
 // - RCX: instantiator or raw_null.
 // Clobbers RCX and RDX.
 // Returns:
 // - true or false in RAX.
-void FlowGraphCompiler::GenerateInstanceOf(intptr_t deopt_id,
-                                           intptr_t token_pos,
+void FlowGraphCompiler::GenerateInstanceOf(intptr_t token_pos,
                                            const AbstractType& type,
                                            bool negate_result,
                                            LocationSummary* locs) {
   ASSERT(type.IsFinalized() && !type.IsMalformed());
 
   const Immediate raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
   Label is_instance, is_not_instance;
   __ pushq(RCX);  // Store instantiator on stack.
   __ pushq(RDX);  // Store instantiator type arguments.
@@ skipping 22 matching lines @@
     // Generate runtime call.
     __ movq(RDX, Address(RSP, 0));  // Get instantiator type arguments.
     __ movq(RCX, Address(RSP, kWordSize));  // Get instantiator.
     __ PushObject(Object::ZoneHandle());  // Make room for the result.
     __ pushq(RAX);  // Push the instance.
     __ PushObject(type);  // Push the type.
     __ pushq(RCX);  // TODO(srdjan): Pass instantiator instead of null.
     __ pushq(RDX);  // Instantiator type arguments.
     __ LoadObject(RAX, test_cache);
     __ pushq(RAX);
-    GenerateCallRuntime(deopt_id, token_pos, kInstanceofRuntimeEntry, locs);
+    GenerateCallRuntime(token_pos, kInstanceofRuntimeEntry, locs);
     // Pop the parameters supplied to the runtime entry. The result of the
     // instanceof runtime call will be left as the result of the operation.
     __ Drop(5);
     if (negate_result) {
       __ popq(RDX);
       __ LoadObject(RAX, bool_true());
       __ cmpq(RDX, RAX);
       __ j(NOT_EQUAL, &done, Assembler::kNearJump);
       __ LoadObject(RAX, bool_false());
     } else {
@@ skipping 18 matching lines @@
 // - Smi -> compile time subtype check (only if dst class is not parameterized).
 // - Class equality (only if class is not parameterized).
 // Inputs:
 // - RAX: object.
 // - RDX: instantiator type arguments or raw_null.
 // - RCX: instantiator or raw_null.
 // Returns:
 // - object in RAX for successful assignable check (or throws TypeError).
 // Performance notes: positive checks must be quick, negative checks can be slow
 // as they throw an exception.
-void FlowGraphCompiler::GenerateAssertAssignable(intptr_t deopt_id,
-                                                 intptr_t token_pos,
+void FlowGraphCompiler::GenerateAssertAssignable(intptr_t token_pos,
                                                  const AbstractType& dst_type,
                                                  const String& dst_name,
                                                  LocationSummary* locs) {
   ASSERT(token_pos >= 0);
   ASSERT(!dst_type.IsNull());
   ASSERT(dst_type.IsFinalized());
   // Assignable check is skipped in FlowGraphBuilder, not here.
   ASSERT(dst_type.IsMalformed() ||
          (!dst_type.IsDynamicType() && !dst_type.IsObjectType()));
   __ pushq(RCX);  // Store instantiator.
   __ pushq(RDX);  // Store instantiator type arguments.
   // A null object is always assignable and is returned as result.
   const Immediate raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
   Label is_assignable, runtime_call;
   __ cmpq(RAX, raw_null);
   __ j(EQUAL, &is_assignable);
 
   // Generate throw new TypeError() if the type is malformed.
   if (dst_type.IsMalformed()) {
     const Error& error = Error::Handle(dst_type.malformed_error());
     const String& error_message = String::ZoneHandle(
         Symbols::New(error.ToErrorCString()));
     __ PushObject(Object::ZoneHandle());  // Make room for the result.
     __ pushq(RAX);  // Push the source object.
     __ PushObject(dst_name);  // Push the name of the destination.
     __ PushObject(error_message);
-    GenerateCallRuntime(deopt_id,
-                        token_pos,
+    GenerateCallRuntime(token_pos,
                         kMalformedTypeErrorRuntimeEntry,
                         locs);
     // We should never return here.
     __ int3();
 
     __ Bind(&is_assignable);  // For a null object.
     __ popq(RDX);  // Remove pushed instantiator type arguments.
     __ popq(RCX);  // Remove pushed instantiator.
     return;
   }
 
   // Generate inline type check, linking to runtime call if not assignable.
   SubtypeTestCache& test_cache = SubtypeTestCache::ZoneHandle();
   test_cache = GenerateInlineInstanceof(token_pos, dst_type,
                                         &is_assignable, &runtime_call);
 
   __ Bind(&runtime_call);
   __ movq(RDX, Address(RSP, 0));  // Get instantiator type arguments.
   __ movq(RCX, Address(RSP, kWordSize));  // Get instantiator.
   __ PushObject(Object::ZoneHandle());  // Make room for the result.
   __ pushq(RAX);  // Push the source object.
   __ PushObject(dst_type);  // Push the type of the destination.
   __ pushq(RCX);  // Instantiator.
   __ pushq(RDX);  // Instantiator type arguments.
   __ PushObject(dst_name);  // Push the name of the destination.
   __ LoadObject(RAX, test_cache);
   __ pushq(RAX);
-  GenerateCallRuntime(deopt_id,
-                      token_pos,
+  GenerateCallRuntime(token_pos,
                       kTypeCheckRuntimeEntry,
                       locs);
   // Pop the parameters supplied to the runtime entry. The result of the
   // type check runtime call is the checked value.
   __ Drop(6);
   __ popq(RAX);
 
   __ Bind(&is_assignable);
   __ popq(RDX);  // Remove pushed instantiator type arguments.
   __ popq(RCX);  // Remove pushed instantiator.
@@ skipping 335 matching lines @@
 #endif
     if (check_arguments) {
       __ Comment("Check argument count");
       // Check that num_fixed <= argc <= num_params.
       Label argc_in_range;
       // Total number of args is the first Smi in args descriptor array (R10).
       __ movq(RAX, FieldAddress(R10, Array::data_offset()));
       __ cmpq(RAX, Immediate(Smi::RawValue(parameter_count)));
       __ j(EQUAL, &argc_in_range, Assembler::kNearJump);
       if (function.IsClosureFunction()) {
-        GenerateCallRuntime(Isolate::kNoDeoptId,
-                            function.token_pos(),
+        GenerateCallRuntime(function.token_pos(),
                             kClosureArgumentMismatchRuntimeEntry,
                             prologue_locs);
       } else {
         __ Stop("Wrong number of arguments");
       }
       __ Bind(&argc_in_range);
     }
     // The arguments descriptor is never saved in the absence of optional
     // parameters, since any argument definition test would always yield true.
     ASSERT(saved_args_desc_var == NULL);
@@ skipping 79 matching lines @@
   } else {
     // Add deoptimization continuation point after the call and before the
     // arguments are removed.
     AddCurrentDescriptor(PcDescriptors::kDeoptAfter,
                          deopt_id,
                          token_pos);
   }
 }
 
 
-void FlowGraphCompiler::GenerateCallRuntime(intptr_t deopt_id,
-                                            intptr_t token_pos,
+void FlowGraphCompiler::GenerateCallRuntime(intptr_t token_pos,
                                             const RuntimeEntry& entry,
                                             LocationSummary* locs) {
   ASSERT(!IsLeaf());
   __ CallRuntime(entry);
-  AddCurrentDescriptor(PcDescriptors::kOther, deopt_id, token_pos);
+  AddCurrentDescriptor(PcDescriptors::kOther, Isolate::kNoDeoptId, token_pos);
   RecordSafepoint(locs);
 }
 
 
 void FlowGraphCompiler::EmitInstanceCall(ExternalLabel* target_label,
                                          const ICData& ic_data,
                                          const Array& arguments_descriptor,
                                          intptr_t argument_count,
                                          intptr_t deopt_id,
                                          intptr_t token_pos,
@@ skipping 239 matching lines @@
 void ParallelMoveResolver::Exchange(const Address& mem1, const Address& mem2) {
   __ Exchange(mem1, mem2);
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64