VM: Improve receiver class check in polymorphic inlining.

runtime/vm/intermediate_language_ia32.cc

Index: runtime/vm/intermediate_language_ia32.cc
===================================================================
--- runtime/vm/intermediate_language_ia32.cc	(revision 33059)
+++ runtime/vm/intermediate_language_ia32.cc	(working copy)
@@ -4581,6 +4581,9 @@
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   summary->set_in(0, Location::RequiresRegister());
   if (!IsNullCheck()) {
+    if (IsDenseSwitch()) {
+      summary->AddTemp(Location::RegisterLocation(ECX));
+    }
     summary->AddTemp(Location::RequiresRegister());
   }
   return summary;
@@ -4615,18 +4618,36 @@
     __ j(ZERO, deopt);
   }
   __ LoadClassId(temp, value);
-  const intptr_t num_checks = unary_checks().NumberOfChecks();
-  const bool use_near_jump = num_checks < 5;
-  for (intptr_t i = cix; i < num_checks; i++) {
-    ASSERT(unary_checks().GetReceiverClassIdAt(i) != kSmiCid);
-    __ cmpl(temp, Immediate(unary_checks().GetReceiverClassIdAt(i)));
-    if (i == (num_checks - 1)) {
-      __ j(NOT_EQUAL, deopt);
-    } else {
-      if (use_near_jump) {
-        __ j(EQUAL, &is_ok, Assembler::kNearJump);
+
+  if (IsDenseSwitch()) {
+    ASSERT(cids_[0] < cids_[cids_.length() - 1]);
+    ASSERT(temp == ECX);
+    Register mask_reg = locs()->temp(1).reg();
+    __ subl(temp, Immediate(cids_[0]));
+    __ cmpl(temp, Immediate(cids_[cids_.length() - 1] - cids_[0]));
+    __ j(ABOVE, deopt);
+    __ movl(mask_reg, Immediate(1));
+    __ shll(mask_reg, temp);
+    intptr_t mask = 0;
+    for (intptr_t i = 0; i < cids_.length(); ++i) {
+      mask |= 1 << (cids_[i] - cids_[0]);
+    }
+    __ andl(mask_reg, Immediate(mask));
+    __ j(ZERO, deopt);
+  } else {
+    const intptr_t num_checks = cids_.length();
+    const bool use_near_jump = num_checks < 5;
+    for (intptr_t i = cix; i < num_checks; i++) {
+      ASSERT(cids_[i] != kSmiCid);
+      __ cmpl(temp, Immediate(cids_[i]));
+      if (i == (num_checks - 1)) {
+        __ j(NOT_EQUAL, deopt);
       } else {
-        __ j(EQUAL, &is_ok);
+        if (use_near_jump) {
+          __ j(EQUAL, &is_ok, Assembler::kNearJump);
+        } else {
+          __ j(EQUAL, &is_ok);
+        }
       }
     }
   }
@@ -4653,6 +4674,32 @@
 }
 
 
+LocationSummary* CheckClassIdInstr::MakeLocationSummary(bool opt) const {
+  const intptr_t kNumInputs = 2;
+  const intptr_t kNumTemps = 0;
+  LocationSummary* summary =
+      new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
+  summary->set_in(0, Location::RequiresRegister());
+  summary->set_in(1, Location::RegisterOrSmiConstant(right()));
+  return summary;
+}
+
+
+void CheckClassIdInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  Register left = locs()->in(0).reg();
+  Location right = locs()->in(1);
+  Label* deopt = compiler->AddDeoptStub(deopt_id(), kDeoptCheckClass);
+  if (right.IsRegister()) {
+    __ cmpl(left, right.reg());
+  } else {
+    ASSERT(right.IsConstant());
+    const Object& right_const = Smi::Cast(right.constant());
+    __ cmpl(left, Immediate(reinterpret_cast<int32_t>(right_const.raw())));
+  }
+  __ j(NOT_ZERO, deopt);
+}
+
+
 // Length: register or constant.
 // Index: register, constant or stack slot.
 LocationSummary* CheckArrayBoundInstr::MakeLocationSummary(bool opt) const {