Optimize checked mode asserts with uninstantiated types and known constant type-arguments.

runtime/vm/intermediate_language.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/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 1454 matching lines @@
   return AbstractType::null();
 }
 
 
 RawAbstractType* CheckEitherNonSmiInstr::CompileType() const {
   return AbstractType::null();
 }
 
 
 // Optimizations that eliminate or simplify individual instructions.
-Instruction* Instruction::Canonicalize() {
+Instruction* Instruction::Canonicalize(FlowGraphOptimizer* optimizer) {
   return this;
 }
 
 
-Definition* Definition::Canonicalize() {
+Definition* Definition::Canonicalize(FlowGraphOptimizer* optimizer) {
   return this;
 }
 
 
-Definition* AssertBooleanInstr::Canonicalize() {
+Definition* AssertBooleanInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
   const intptr_t value_cid = value()->ResultCid();
   return (value_cid == kBoolCid) ? value()->definition() : this;
 }
 
 
-Definition* AssertAssignableInstr::Canonicalize() {
+Definition* AssertAssignableInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
   // (1) Replace the assert with its input if the input has a known compatible
   // class-id. The class-ids handled here are those that are known to be
   // results of IL instructions.
   intptr_t cid = value()->ResultCid();
   bool is_redundant = false;
   if (dst_type().IsIntType()) {
     is_redundant = (cid == kSmiCid) || (cid == kMintCid);
   } else if (dst_type().IsDoubleType()) {
     is_redundant = (cid == kDoubleCid);
   } else if (dst_type().IsBoolType()) {
     is_redundant = (cid == kBoolCid);
   }
   if (is_redundant) return value()->definition();
 
   // (2) Replace the assert with its input if the input is the result of a
   // compatible assert itself.
   AssertAssignableInstr* check = value()->definition()->AsAssertAssignable();
-  if ((check != NULL) && (check->dst_type().raw() == dst_type().raw())) {
+  if ((check != NULL) &&
+      (check->dst_type().Canonicalize() == dst_type().Canonicalize())) {

[regis, 2012/11/29 16:25:19]

Aren't the types canonicalized already? It may be worth asserting that they are
and fix the code upstream if they are not.

[Florian Schneider, 2012/12/04 14:48:04]

They are not all canonicalized. For now, I'm using Equals instead of comparing
raw objects. 

[regis, 2012/12/05 19:08:02]

"For now"? Please add a TODO.
Why are they not canonicalized? That was my first question. We need to
understand why and canonicalize them or explain in a comment under what
circumstances they are not canonicalized.

     // TODO(fschneider): Propagate type-assertions across phi-nodes.
     // TODO(fschneider): Eliminate more asserts with subtype relation.
     return check;
   }
+
+  // (3) For uninstantiated target types: If the instantiator type arguments
+  // are constant, instantiate the target type here.
+  if (dst_type().IsInstantiated()) return this;
+
+  ConstantInstr* constant_type_args =
+      instantiator_type_arguments()->definition()->AsConstant();
+  if (constant_type_args != NULL &&
+      !constant_type_args->value().IsNull() &&
+      constant_type_args->value().IsTypeArguments()) {
+    const TypeArguments& instantiator_type_args =
+        TypeArguments::Cast(constant_type_args->value());
+    const AbstractType& new_dst_type = AbstractType::ZoneHandle(
+        dst_type().InstantiateFrom(instantiator_type_args));

[regis, 2012/11/29 16:25:19]

You should canonicalize new_dst_type here.

[Florian Schneider, 2012/12/04 14:48:04]

Done.

+    set_dst_type(new_dst_type);
+    ConstantInstr* null_constant = new ConstantInstr(Object::ZoneHandle());
+    // It is ok to insert instructions before the current during
+    // forward iteration.
+    optimizer->InsertBefore(this, null_constant, NULL, Definition::kValue);
+    instantiator_type_arguments()->RemoveFromInputUseList();
+    instantiator_type_arguments()->set_definition(null_constant);
+    instantiator_type_arguments()->AddToInputUseList();
+  }
   return this;
 }
 
-Definition* StrictCompareInstr::Canonicalize() {
+Definition* StrictCompareInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
   if (!right()->BindsToConstant()) return this;
   const Object& right_constant = right()->BoundConstant();
   Definition* left_defn = left()->definition();
   // TODO(fschneider): Handle other cases: e === false and e !== true/false.
   // Handles e === true.
   if ((kind() == Token::kEQ_STRICT) &&
       (right_constant.raw() == Bool::True()) &&
       (left()->ResultCid() == kBoolCid)) {
     // Return left subexpression as the replacement for this instruction.
     return left_defn;
   }
   return this;
 }
 
 
-Instruction* CheckClassInstr::Canonicalize() {
+Instruction* CheckClassInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
   const intptr_t value_cid = value()->ResultCid();
   const intptr_t num_checks = unary_checks().NumberOfChecks();
   if ((num_checks == 1) &&
       (value_cid == unary_checks().GetReceiverClassIdAt(0))) {
     // No checks needed.
     return NULL;
   }
   return this;
 }
 
 
-Instruction* CheckSmiInstr::Canonicalize() {
+Instruction* CheckSmiInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
   return (value()->ResultCid() == kSmiCid) ?  NULL : this;
 }
 
 
-Instruction* CheckEitherNonSmiInstr::Canonicalize() {
+Instruction* CheckEitherNonSmiInstr::Canonicalize(
+    FlowGraphOptimizer* optimizer) {
   if ((left()->ResultCid() == kDoubleCid) ||
       (right()->ResultCid() == kDoubleCid)) {
     return NULL;  // Remove from the graph.
   }
   return this;
 }
 
 
 // Shared code generation methods (EmitNativeCode, MakeLocationSummary, and
 // PrepareEntry). Only assembly code that can be shared across all architectures
@@ skipping 1149 matching lines @@
     default:
       UNREACHABLE();
       return -1;
   }
 }
 
 
 #undef __
 
 }  // namespace dart