Use off-heap data for type feedback in PolymorphicInstanceCallInstr

runtime/vm/flow_graph_compiler_ia32.cc

Index: runtime/vm/flow_graph_compiler_ia32.cc
diff --git a/runtime/vm/flow_graph_compiler_ia32.cc b/runtime/vm/flow_graph_compiler_ia32.cc
index 8052e0cc43c75632fe8c8447f1851321a2f514e2..8345aee7a80b5e1f9f2f6651c8b4842de6d96d48 100644
--- a/runtime/vm/flow_graph_compiler_ia32.cc
+++ b/runtime/vm/flow_graph_compiler_ia32.cc
@@ -1183,16 +1183,14 @@ void FlowGraphCompiler::EmitInstanceCall(const StubEntry& stub_entry,
 
 
 void FlowGraphCompiler::EmitMegamorphicInstanceCall(
-    const ICData& ic_data,
+    const String& name,
+    const Array& arguments_descriptor,
     intptr_t argument_count,
     intptr_t deopt_id,
     TokenPosition token_pos,
     LocationSummary* locs,
     intptr_t try_index,
     intptr_t slow_path_argument_count) {
-  const String& name = String::Handle(zone(), ic_data.target_name());
-  const Array& arguments_descriptor =
-      Array::ZoneHandle(zone(), ic_data.arguments_descriptor());
   ASSERT(!arguments_descriptor.IsNull() && (arguments_descriptor.Length() > 0));
   const MegamorphicCache& cache = MegamorphicCache::ZoneHandle(
       zone(),
@@ -1392,7 +1390,8 @@ void FlowGraphCompiler::ClobberDeadTempRegisters(LocationSummary* locs) {
 #endif
 
 
-void FlowGraphCompiler::EmitTestAndCall(const ICData& ic_data,
+void FlowGraphCompiler::EmitTestAndCall(const PolymorphicTargets& targets,
+                                        const String& function_name,
                                         intptr_t argument_count,
                                         const Array& argument_names,
                                         Label* failed,
@@ -1411,47 +1410,60 @@ void FlowGraphCompiler::EmitTestAndCall(const ICData& ic_data,
   __ movl(EAX, Address(ESP, (argument_count - 1) * kWordSize));
   __ LoadObject(EDX, arguments_descriptor);
 
-  const bool kFirstCheckIsSmi = ic_data.GetReceiverClassIdAt(0) == kSmiCid;
-  const intptr_t num_checks = ic_data.NumberOfChecks();
-
-  ASSERT(!ic_data.IsNull() && (num_checks > 0));
+  const int kNoCase = -1;
+  int smi_case = kNoCase;
+  int which_case_to_skip = kNoCase;
+
+  const int length = targets.length();
+  int non_smi_length = length;
+
+  // Find out if one of the classes in one of the cases is the Smi class. We
+  // will be handling that specially.
+  for (int i = 0; i < length; i++) {
+    const intptr_t start = targets[i].cid_start;
+    if (start > kSmiCid) continue;
+    const intptr_t end = targets[i].cid_end;
+    if (end >= kSmiCid) {
+      smi_case = i;
+      if (start == kSmiCid && end == kSmiCid) {
+        // If this case has only the Smi class then we won't need to emit it at
+        // all later.
+        which_case_to_skip = i;
+        non_smi_length--;
+      }
+      break;
+    }
+  }
 
-  Label after_smi_test;
   __ testl(EAX, Immediate(kSmiTagMask));
-  if (kFirstCheckIsSmi) {
+
+  if (smi_case != kNoCase) {
+    Label after_smi_test;
     // Jump if receiver is not Smi.
-    if (num_checks == 1) {
-      __ j(NOT_ZERO, failed);
-    } else {
-      __ j(NOT_ZERO, &after_smi_test);
-    }
+    __ j(NOT_ZERO, non_smi_length == 0 ? failed : &after_smi_test);
     // Do not use the code from the function, but let the code be patched so
     // that we can record the outgoing edges to other code.
+    const Function& function = *targets[smi_case].target;
     GenerateDartCall(deopt_id, token_index,
                      *StubCode::CallStaticFunction_entry(),
                      RawPcDescriptors::kOther, locs);
-    const Function& function =
-        Function::ZoneHandle(zone(), ic_data.GetTargetAt(0));
     AddStaticCallTarget(function);
+
     __ Drop(argument_count);
-    if (num_checks > 1) {
+    if (non_smi_length > 0) {
       __ jmp(match_found);
     }
+    __ Bind(&after_smi_test);
   } else {
     // Receiver is Smi, but Smi is not a valid class therefore fail.
-    // (Smi class must be first in the list).
     __ j(ZERO, failed);
   }
-  __ Bind(&after_smi_test);
 
-  ASSERT(!ic_data.IsNull() && (num_checks > 0));
-  GrowableArray<CidRangeTarget> sorted(num_checks);
-  SortICDataByCount(ic_data, &sorted, /* drop_smi = */ true);
+  ASSERT(length > 0);
 
-  const intptr_t sorted_len = sorted.length();
-  // If sorted_len is 0 then only a Smi check was needed; the Smi check above
-  // will fail if there was only one check and receiver is not Smi.
-  if (sorted_len == 0) return;
+  // If non_smi_length is 0 then only a Smi check was needed; the Smi check
+  // above will fail if there was only one check and receiver is not Smi.
+  if (non_smi_length == 0) return;
 
   // Value is not Smi,
   __ LoadClassId(EDI, EAX);
@@ -1459,51 +1471,54 @@ void FlowGraphCompiler::EmitTestAndCall(const ICData& ic_data,
   bool add_megamorphic_call = false;
   const int kMaxImmediateInInstruction = 127;
   int bias =
-      ComputeGoodBiasForCidComparison(sorted, kMaxImmediateInInstruction);
+      ComputeGoodBiasForCidComparison(targets, kMaxImmediateInInstruction);
   if (bias != 0) __ addl(EDI, Immediate(-bias));
 
-  for (intptr_t i = 0; i < sorted_len; i++) {
-    const bool is_last_check = (i == (sorted_len - 1));
-    int cid_start = sorted[i].cid_start;
-    int cid_end = sorted[i].cid_end;
-    int count = sorted[i].count;
-    if (!is_last_check && !complete && count < (total_ic_calls >> 5)) {
+  int last_check = which_case_to_skip == length - 1 ? length - 2 : length - 1;
+
+  for (intptr_t i = 0; i < length; i++) {
+    if (i == which_case_to_skip) continue;
+    const bool is_last_check = (i == last_check);
+    int cid_start = targets[i].cid_start;
+    int cid_end = targets[i].cid_end;
+    int count = targets[i].count;
+    if (!is_last_check && !complete && count <= (total_ic_calls >> 5)) {
       // This case is hit too rarely to be worth writing class-id checks inline
-      // for.
+      // for.  Note that we can't do this for calls with only one target because
+      // the type propagator may have made use of that and expects a deopt if
+      // a new class is seen at this calls site.  See HasSingleRecognizedCid.
       add_megamorphic_call = true;
       break;
     }
-    ASSERT(cid_start > kSmiCid || cid_end < kSmiCid);
     Label next_test;
-    if (!complete || !is_last_check) {
-      Label* next_label = is_last_check ? failed : &next_test;
-      if (cid_start == cid_end) {
-        __ cmpl(EDI, Immediate(cid_start - bias));
-        __ j(NOT_EQUAL, next_label);
-      } else {
-        __ addl(EDI, Immediate(bias - cid_start));
-        bias = cid_start;
-        __ cmpl(EDI, Immediate(cid_end - cid_start));
-        __ j(ABOVE, next_label);  // Unsigned higher.
-      }
+    Label* next_label = is_last_check ? failed : &next_test;
+    if (cid_start == cid_end) {
+      __ cmpl(EDI, Immediate(cid_start - bias));
+      __ j(NOT_EQUAL, next_label);
+    } else {
+      __ addl(EDI, Immediate(bias - cid_start));
+      bias = cid_start;
+      __ cmpl(EDI, Immediate(cid_end - cid_start));
+      __ j(ABOVE, next_label);  // Unsigned higher.
     }
     // Do not use the code from the function, but let the code be patched so
     // that we can record the outgoing edges to other code.
-    const Function& function = *sorted[i].target;
+    const Function& function = *targets[i].target;
     GenerateDartCall(deopt_id, token_index,
                      *StubCode::CallStaticFunction_entry(),
                      RawPcDescriptors::kOther, locs);
     AddStaticCallTarget(function);
     __ Drop(argument_count);
-    if (!is_last_check) {
+    if (!is_last_check || add_megamorphic_call) {
       __ jmp(match_found);
     }
     __ Bind(&next_test);
   }
   if (add_megamorphic_call) {
-    int try_index = CatchClauseNode::kInvalidTryIndex;
-    EmitMegamorphicInstanceCall(ic_data, argument_count, deopt_id, token_index,
-                                locs, try_index, argument_count);
+    const int try_index = CatchClauseNode::kInvalidTryIndex;
+    EmitMegamorphicInstanceCall(function_name, arguments_descriptor,
+                                argument_count, deopt_id, token_index, locs,
+                                try_index);
   }
 }