[VM] Introduce function and osr entrypoints to the VM's IR

Similar to how we treat catch entry instructions, this cl adds new
function and osr entry instructions. The [FunctionEntry] and
[OsrEntry] - just like [CatchBlockEntry] - have now their own initial
definitions. The [GraphEntry] has only initial definitions for
constants.

Explicit phis are inserted for all parameter / special parameter
instructions if necessary.

Future work is:

  a) Minimize parallel moves due to the phis on parameters
  b) Cleanup frame setup: Move it entirely into FunctionEntry/CatchEntry
    (instead of the split version we have now)

Fixes dart-lang/sdk#34435
Fixes dart-lang/sdk#34287

Change-Id: Iefa0280a709716f748d6fb0523b8d0f4d8de1fec
Reviewed-on: https://dart-review.googlesource.com/c/74782
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>

Author: mkustermann

runtime/observatory/tests/service/rewind_test.dart

@@ -1,7 +1,6 @@
 // Copyright (c) 2016, 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.
-// VMOptions=--no-sync-async
 
 import 'dart:developer';
 import 'package:observatory/service_io.dart';
@@ -12,10 +11,10 @@ import 'test_helper.dart';
 const alwaysInline = "AlwaysInline";
 const noInline = "NeverInline";
 
-int LINE_A = 35;
-int LINE_B = 40;
-int LINE_C = 43;
-int LINE_D = 47;
+int LINE_A = 34;
+int LINE_B = 39;
+int LINE_C = 42;
+int LINE_D = 46;
 
 int global = 0;
 
@@ -60,20 +59,20 @@ var tests = <IsolateTest>[
     } on ServerRpcException catch (e) {
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kCannotResume));
-      expect(e.message, 'Frame must be in bounds [1..9]: saw 0');
+      expect(e.message, 'Frame must be in bounds [1..12]: saw 0');
     }
     expect(caughtException, isTrue);
   },
   (Isolate isolate) async {
-    // We are not able to rewind frame 10.
+    // We are not able to rewind frame 13.
     bool caughtException;
     try {
-      await isolate.rewind(10);
+      await isolate.rewind(13);
       expect(false, isTrue, reason: 'Unreachable');
     } on ServerRpcException catch (e) {
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kCannotResume));
-      expect(e.message, 'Frame must be in bounds [1..9]: saw 10');
+      expect(e.message, 'Frame must be in bounds [1..12]: saw 13');
     }
     expect(caughtException, isTrue);
   },

runtime/observatory/tests/service/service.status

@@ -104,7 +104,7 @@ step_through_getter_test: RuntimeError # Debugging StringConcatenation doesn't w
 *: SkipByDesign
 
 [ $compiler == dartk || $compiler == dartkp ]
-rewind_test: Pass, RuntimeError, Slow # Issue 34287
+rewind_test: Pass, Slow
 
 # Skip all service tests because random reloads interfere.
 [ $hot_reload || $hot_reload_rollback ]

runtime/tests/vm/vm.status

@@ -51,6 +51,9 @@ dart/simd128float32_test: Skip # compilers not aware of Simd128
 dart/truncating_ints_test: SkipByDesign # The test requires int64.
 dart/wrap_around_in_range_analysis_test: SkipByDesign # The test requires int64.
 
+[ $compiler != dartk || ($arch != x64 && $arch != simarm && $arch != arm) || $hot_reload || $hot_reload_rollback ]
+dart/entrypoints/*: Skip  # Only supported in Dart 2 JIT (hot-reload -> issue 34199).
+
 [ ($compiler == dartk || $compiler == dartkb) ]
 cc/DartAPI_New: Fail # Issue #33041
 dart/redirection_type_shuffling_test/00: RuntimeError, Pass

runtime/vm/compiler/backend/block_scheduler.cc

@@ -71,10 +71,15 @@ void BlockScheduler::AssignEdgeWeights() const {
   Array& edge_counters = Array::Handle();
   edge_counters ^= ic_data_array.At(0);
 
-  intptr_t entry_count = GetEdgeCount(
-      edge_counters,
-      flow_graph()->graph_entry()->normal_entry()->preorder_number());
-  flow_graph()->graph_entry()->set_entry_count(entry_count);
+  auto graph_entry = flow_graph()->graph_entry();
+  BlockEntryInstr* entry = graph_entry->normal_entry();
+  if (entry == nullptr) {
+    entry = graph_entry->osr_entry();
+    ASSERT(entry != nullptr);
+  }
+  const intptr_t entry_count =
+      GetEdgeCount(edge_counters, entry->preorder_number());
+  graph_entry->set_entry_count(entry_count);
 
   for (BlockIterator it = flow_graph()->reverse_postorder_iterator();
        !it.Done(); it.Advance()) {

runtime/vm/compiler/backend/branch_optimizer.cc

@@ -61,7 +61,7 @@ bool BranchSimplifier::Match(JoinEntryInstr* block) {
 }
 
 JoinEntryInstr* BranchSimplifier::ToJoinEntry(Zone* zone,
-                                              TargetEntryInstr* target) {
+                                              BlockEntryInstr* target) {
   // Convert a target block into a join block.  Branches will be duplicated
   // so the former true and false targets become joins of the control flows
   // from all the duplicated branches.
@@ -74,6 +74,17 @@ JoinEntryInstr* BranchSimplifier::ToJoinEntry(Zone* zone,
   return join;
 }
 
+TargetEntryInstr* BranchSimplifier::ToTargetEntry(Zone* zone,
+                                                  BlockEntryInstr* target) {
+  auto replacement = new (zone)
+      TargetEntryInstr(target->block_id(), target->try_index(), DeoptId::kNone);
+  replacement->InheritDeoptTarget(zone, target);
+  replacement->LinkTo(target->next());
+  replacement->set_last_instruction(target->last_instruction());
+  target->UnuseAllInputs();
+  return replacement;
+}
+
 BranchInstr* BranchSimplifier::CloneBranch(Zone* zone,
                                            BranchInstr* branch,
                                            Value* new_left,

runtime/vm/compiler/backend/branch_optimizer.h

@@ -9,7 +9,9 @@
 
 namespace dart {
 
+class BlockEntryInstr;
 class FlowGraph;
+class FunctionEntryInstr;
 class JoinEntryInstr;
 class Zone;
 class TargetEntryInstr;
@@ -23,10 +25,15 @@ class BranchSimplifier : public AllStatic {
  public:
   static void Simplify(FlowGraph* flow_graph);
 
-  // Replace a target entry instruction with a join entry instruction.  Does
+  // Replace a block entry instruction with a join entry instruction.  Does
   // not update the original target's predecessors to point to the new block
   // and does not replace the target in already computed block order lists.
-  static JoinEntryInstr* ToJoinEntry(Zone* zone, TargetEntryInstr* target);
+  static JoinEntryInstr* ToJoinEntry(Zone* zone, BlockEntryInstr* target);
+
+  // Replace a block entry instruction with a target entry instruction.  Does
+  // not update the original target's predecessors to point to the new block and
+  // does not replace the target in already computed block order lists.
+  static TargetEntryInstr* ToTargetEntry(Zone* zone, BlockEntryInstr* target);
 
  private:
   // Match an instance of the pattern to rewrite.  See the implementation

runtime/vm/compiler/backend/constant_propagator.cc

@@ -121,9 +121,8 @@ void ConstantPropagator::Join(Object* left, const Object& right) {
 // Analysis of blocks.  Called at most once per block.  The block is already
 // marked as reachable.  All instructions in the block are analyzed.
 void ConstantPropagator::VisitGraphEntry(GraphEntryInstr* block) {
-  const GrowableArray<Definition*>& defs = *block->initial_definitions();
-  for (intptr_t i = 0; i < defs.length(); ++i) {
-    defs[i]->Accept(this);
+  for (auto def : *block->initial_definitions()) {
+    def->Accept(this);
   }
   ASSERT(ForwardInstructionIterator(block).Done());
 
@@ -134,30 +133,47 @@ void ConstantPropagator::VisitGraphEntry(GraphEntryInstr* block) {
   }
 }
 
-void ConstantPropagator::VisitJoinEntry(JoinEntryInstr* block) {
-  // Phis are visited when visiting Goto at a predecessor. See VisitGoto.
+void ConstantPropagator::VisitFunctionEntry(FunctionEntryInstr* block) {
+  for (auto def : *block->initial_definitions()) {
+    def->Accept(this);
+  }
   for (ForwardInstructionIterator it(block); !it.Done(); it.Advance()) {
     it.Current()->Accept(this);
   }
 }
 
-void ConstantPropagator::VisitTargetEntry(TargetEntryInstr* block) {
+void ConstantPropagator::VisitOsrEntry(OsrEntryInstr* block) {
+  for (auto def : *block->initial_definitions()) {
+    def->Accept(this);
+  }
   for (ForwardInstructionIterator it(block); !it.Done(); it.Advance()) {
     it.Current()->Accept(this);
   }
 }
 
-void ConstantPropagator::VisitIndirectEntry(IndirectEntryInstr* block) {
+void ConstantPropagator::VisitCatchBlockEntry(CatchBlockEntryInstr* block) {
+  for (auto def : *block->initial_definitions()) {
+    def->Accept(this);
+  }
   for (ForwardInstructionIterator it(block); !it.Done(); it.Advance()) {
     it.Current()->Accept(this);
   }
 }
 
-void ConstantPropagator::VisitCatchBlockEntry(CatchBlockEntryInstr* block) {
-  const GrowableArray<Definition*>& defs = *block->initial_definitions();
-  for (intptr_t i = 0; i < defs.length(); ++i) {
-    defs[i]->Accept(this);
+void ConstantPropagator::VisitJoinEntry(JoinEntryInstr* block) {
+  // Phis are visited when visiting Goto at a predecessor. See VisitGoto.
+  for (ForwardInstructionIterator it(block); !it.Done(); it.Advance()) {
+    it.Current()->Accept(this);
   }
+}
+
+void ConstantPropagator::VisitTargetEntry(TargetEntryInstr* block) {
+  for (ForwardInstructionIterator it(block); !it.Done(); it.Advance()) {
+    it.Current()->Accept(this);
+  }
+}
+
+void ConstantPropagator::VisitIndirectEntry(IndirectEntryInstr* block) {
   for (ForwardInstructionIterator it(block); !it.Done(); it.Advance()) {
     it.Current()->Accept(this);
   }