VM(RegExp): Allow OSR optimization of RegExp :matcher functions.

runtime/vm/regexp_assembler_ir.cc

 // Copyright (c) 2014, 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/regexp_assembler_ir.h"
 
 #include "vm/bit_vector.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 60 matching lines @@
  * indices of -1 denote non-matched groups. Note that we store these indices
  * as a negative offset from the end of the string in registers_array_
  * during processing, and convert them to standard indexes when copying them
  * to matches_param_ on successful match.
  */
 IRRegExpMacroAssembler::IRRegExpMacroAssembler(
     intptr_t specialization_cid,
     intptr_t capture_count,
     const ParsedFunction* parsed_function,
     const ZoneGrowableArray<const ICData*>& ic_data_array,
+    intptr_t osr_id,
     Zone* zone)
     : RegExpMacroAssembler(zone),
       thread_(Thread::Current()),
       specialization_cid_(specialization_cid),
       parsed_function_(parsed_function),
       ic_data_array_(ic_data_array),
       current_instruction_(NULL),
       stack_(NULL),
       stack_pointer_(NULL),
       current_character_(NULL),
@@ skipping 27 matching lines @@
   stack_array_cell_.SetAt(
       0,
       TypedData::Handle(zone, TypedData::New(kTypedDataInt32ArrayCid,
                                              kMinStackSize / 4, Heap::kOld)));
 
   // Create and generate all preset blocks.
   entry_block_ = new (zone) GraphEntryInstr(
       *parsed_function_,
       new (zone) TargetEntryInstr(block_id_.Alloc(), kInvalidTryIndex,
                                   GetNextDeoptId()),
-      Compiler::kNoOSRDeoptId);
+      osr_id);
   start_block_ = new (zone)
       JoinEntryInstr(block_id_.Alloc(), kInvalidTryIndex, GetNextDeoptId());
   success_block_ = new (zone)
       JoinEntryInstr(block_id_.Alloc(), kInvalidTryIndex, GetNextDeoptId());
   backtrack_block_ = new (zone)
       JoinEntryInstr(block_id_.Alloc(), kInvalidTryIndex, GetNextDeoptId());
   exit_block_ = new (zone)
       JoinEntryInstr(block_id_.Alloc(), kInvalidTryIndex, GetNextDeoptId());
 
   GenerateEntryBlock();
@@ skipping 77 matching lines @@
   StoreLocal(stack_pointer_, Bind(Int64Constant(-1)));
 
   // Jump to the start block.
   current_instruction_->Goto(start_block_);
 }
 
 
 void IRRegExpMacroAssembler::GenerateBacktrackBlock() {
   set_current_instruction(backtrack_block_);
   TAG();
-  CheckPreemption();
+  CheckPreemption(/*is_backtrack=*/true);
 
   const intptr_t entries_count = entry_block_->indirect_entries().length();
 
   TypedData& offsets = TypedData::ZoneHandle(
       Z, TypedData::New(kTypedDataInt32ArrayCid, entries_count, Heap::kOld));
 
   PushArgumentInstr* block_offsets_push =
       PushArgument(Bind(new (Z) ConstantInstr(offsets)));
   PushArgumentInstr* block_id_push = PushArgument(Bind(PopStack()));
 
@@ skipping 1523 matching lines @@
       new (Z) IndirectEntryInstr(block_id_.Alloc(), indirect_id_.Alloc(),
                                  kInvalidTryIndex, GetNextDeoptId());
   blocks_.Add(target);
 
   target->AppendInstruction(new (Z) GotoInstr(dst, GetNextDeoptId()));
 
   return target;
 }
 
 
-void IRRegExpMacroAssembler::CheckPreemption() {
+void IRRegExpMacroAssembler::CheckPreemption(bool is_backtrack) {
   TAG();
-  AppendInstruction(new (Z) CheckStackOverflowInstr(TokenPosition::kNoSource, 0,
-                                                    GetNextDeoptId()));
+
+  // Setting non-zero loop_depth turns this CheckStackOverflow into

[erikcorry, 2017/06/21 07:54:07]

This is confusing.  "Turns it into an OSR entry" sounds like it affects the
'kind' flag which can be either kOsrEntry or kFull.  Perhaps:

Perhaps it's clearer to rename kFull to kOsrAndPreemption?  And/or  write:

// We don't have the loop_depth available when compiling regexps, but
// we set loop_depth to a non-zero value because this instruction does
// not emit OSR entry information outside loops.

[Vyacheslav Egorov (Google), 2017/06/21 11:42:04]

Done.

+  // an OSR entry.
+  AppendInstruction(new (Z) CheckStackOverflowInstr(
+      TokenPosition::kNoSource,
+      /*loop_depth=*/1, GetNextDeoptId(),
+      is_backtrack ? CheckStackOverflowInstr::kFull
+                   : CheckStackOverflowInstr::kOsrEntry));
 }
 
 
 Definition* IRRegExpMacroAssembler::Add(PushArgumentInstr* lhs,
                                         PushArgumentInstr* rhs) {
   return InstanceCall(InstanceCallDescriptor::FromToken(Token::kADD), lhs, rhs);
 }
 
 
 Definition* IRRegExpMacroAssembler::Sub(PushArgumentInstr* lhs,
@@ skipping 68 matching lines @@
 
   return Bind(new (Z) LoadCodeUnitsInstr(pattern_val, index_val, characters,
                                          specialization_cid_,
                                          TokenPosition::kNoSource));
 }
 
 
 #undef __
 
 }  // namespace dart