Add support for javascript incompatibility warnings.

runtime/vm/flow_graph_optimizer.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/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
+#include "vm/exceptions.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/hash_map.h"
 #include "vm/il_printer.h"
 #include "vm/intermediate_language.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/resolver.h"
 #include "vm/scopes.h"
 #include "vm/stack_frame.h"
@@ skipping 19 matching lines @@
     "Print live sets for load optimization pass.");
 DEFINE_FLAG(bool, trace_optimization, false, "Print optimization details.");
 DEFINE_FLAG(bool, trace_range_analysis, false, "Trace range analysis progress");
 DEFINE_FLAG(bool, truncating_left_shift, true,
     "Optimize left shift to truncate if possible");
 DEFINE_FLAG(bool, use_cha, true, "Use class hierarchy analysis.");
 DECLARE_FLAG(bool, eliminate_type_checks);
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, source_lines);
 DECLARE_FLAG(bool, trace_type_check_elimination);
+DECLARE_FLAG(bool, warn_on_javascript_compatibility);
 
 static bool ShouldInlineSimd() {
   return FlowGraphCompiler::SupportsUnboxedSimd128();
 }
 
 
 // Optimize instance calls using ICData.
 void FlowGraphOptimizer::ApplyICData() {
   VisitBlocks();
 }
@@ skipping 43 matching lines @@
 
 
 // Attempt to build ICData for call using propagated class-ids.
 bool FlowGraphOptimizer::TryCreateICData(InstanceCallInstr* call) {
   ASSERT(call->HasICData());
   if (call->ic_data()->NumberOfChecks() > 0) {
     // This occurs when an instance call has too many checks, will be converted
     // to megamorphic call.
     return false;
   }
+  if (FLAG_warn_on_javascript_compatibility) {
+    // Do not make the instance call megamorphic if the callee needs to decode
+    // the calling code sequence to lookup the ic data and verify if a warning
+    // has already been issued or not.
+    // TryCreateICData is only invoked if the ic_data target has not been called
+    // yet, so no warning can possibly have been issued.
+    ASSERT(!call->ic_data()->IssuedJSWarning());
+    if (call->ic_data()->MayCheckForJSWarning()) {
+      return false;
+    }
+  }
   GrowableArray<intptr_t> class_ids(call->ic_data()->NumArgsTested());
   ASSERT(call->ic_data()->NumArgsTested() <= call->ArgumentCount());
   for (intptr_t i = 0; i < call->ic_data()->NumArgsTested(); i++) {
     const intptr_t cid = call->PushArgumentAt(i)->value()->Type()->ToCid();
     class_ids.Add(cid);
   }
 
   const Token::Kind op_kind = call->token_kind();
   if (Token::IsRelationalOperator(op_kind) ||
       Token::IsEqualityOperator(op_kind) ||
@@ skipping 3742 matching lines @@
   ASSERT(Token::IsTypeTestOperator(call->token_kind()));
   Definition* left = call->ArgumentAt(0);
   Definition* instantiator = call->ArgumentAt(1);
   Definition* type_args = call->ArgumentAt(2);
   const AbstractType& type =
       AbstractType::Cast(call->ArgumentAt(3)->AsConstant()->value());
   const bool negate = Bool::Cast(
       call->ArgumentAt(4)->OriginalDefinition()->AsConstant()->value()).value();
   const ICData& unary_checks =
       ICData::ZoneHandle(call->ic_data()->AsUnaryClassChecks());
+  if (FLAG_warn_on_javascript_compatibility &&
+      !unary_checks.IssuedJSWarning() &&
+      (type.IsIntType() || type.IsDoubleType() || !type.IsInstantiated())) {
+    // No warning was reported yet for this type check, either because it has
+    // not been executed yet, or because no problematic combinations of instance
+    // type and test type have been encountered so far. A warning may still be
+    // reported, so do not replace the instance call.
+    return;
+  }
   if (unary_checks.NumberOfChecks() <= FLAG_max_polymorphic_checks) {
     ZoneGrowableArray<intptr_t>* results =
         new ZoneGrowableArray<intptr_t>(unary_checks.NumberOfChecks() * 2);
     Bool& as_bool =
         Bool::ZoneHandle(InstanceOfAsBool(unary_checks, type, results));
     if (as_bool.IsNull()) {
       if (results->length() == unary_checks.NumberOfChecks() * 2) {
         const bool can_deopt = TryExpandTestCidsResult(results, type);
         TestCidsInstr* test_cids = new TestCidsInstr(
             call->token_pos(),
@@ skipping 61 matching lines @@
 void FlowGraphOptimizer::ReplaceWithTypeCast(InstanceCallInstr* call) {
   ASSERT(Token::IsTypeCastOperator(call->token_kind()));
   Definition* left = call->ArgumentAt(0);
   Definition* instantiator = call->ArgumentAt(1);
   Definition* type_args = call->ArgumentAt(2);
   const AbstractType& type =
       AbstractType::Cast(call->ArgumentAt(3)->AsConstant()->value());
   ASSERT(!type.IsMalformedOrMalbounded());
   const ICData& unary_checks =
       ICData::ZoneHandle(call->ic_data()->AsUnaryClassChecks());
+  if (FLAG_warn_on_javascript_compatibility &&
+      !unary_checks.IssuedJSWarning() &&
+      (type.IsIntType() || type.IsDoubleType() || !type.IsInstantiated())) {
+    // No warning was reported yet for this type check, either because it has
+    // not been executed yet, or because no problematic combinations of instance
+    // type and test type have been encountered so far. A warning may still be
+    // reported, so do not replace the instance call.
+    return;
+  }
   if (unary_checks.NumberOfChecks() <= FLAG_max_polymorphic_checks) {
     ZoneGrowableArray<intptr_t>* results =
         new ZoneGrowableArray<intptr_t>(unary_checks.NumberOfChecks() * 2);
     const Bool& as_bool =
         Bool::ZoneHandle(InstanceOfAsBool(unary_checks, type, results));
     if (as_bool.raw() == Bool::True().raw()) {
       AddReceiverCheck(call);
       // Remove the original push arguments.
       for (intptr_t i = 0; i < call->ArgumentCount(); ++i) {
         PushArgumentInstr* push = call->PushArgumentAt(i);
@@ skipping 5552 matching lines @@
   }
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, alloc->cls(), *slots);
   }
 }
 
 
 }  // namespace dart