Implements OSR for arm and mips.

runtime/vm/intermediate_language_mips.cc

 // Copyright (c) 2013, 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/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/locations.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/simulator.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 
 #define __ compiler->assembler()->
 
 namespace dart {
 
 DECLARE_FLAG(int, optimization_counter_threshold);
 DECLARE_FLAG(bool, propagate_ic_data);
+DECLARE_FLAG(bool, use_osr);
 
 // Generic summary for call instructions that have all arguments pushed
 // on the stack and return the result in a fixed register V0.
 LocationSummary* Instruction::MakeCallSummary() {
   LocationSummary* result = new LocationSummary(0, 0, LocationSummary::kCall);
   result->set_out(Location::RegisterLocation(V0));
   return result;
 }
 
 
@@ skipping 2117 matching lines @@
      compiler->assembler()->CodeSize();
 
   __ Bind(&next);
   __ mov(RA, TMP);  // Restore return address.
   __ lw(PP, Address(CMPRES, -object_pool_pc_dist));
 }
 
 
 LocationSummary* CheckStackOverflowInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 0;
-  const intptr_t kNumTemps = 0;
+  const intptr_t kNumTemps = 1;
   LocationSummary* summary =
       new LocationSummary(kNumInputs,
                           kNumTemps,
                           LocationSummary::kCallOnSlowPath);
+  summary->set_temp(0, Location::RequiresRegister());
   return summary;
 }
 
 
 class CheckStackOverflowSlowPath : public SlowPathCode {
  public:
   explicit CheckStackOverflowSlowPath(CheckStackOverflowInstr* instruction)
       : instruction_(instruction) { }
 
   virtual void EmitNativeCode(FlowGraphCompiler* compiler) {
     __ TraceSimMsg("CheckStackOverflowSlowPath");
     __ Comment("CheckStackOverflowSlowPath");
     __ Bind(entry_label());
     compiler->SaveLiveRegisters(instruction_->locs());
     // pending_deoptimization_env_ is needed to generate a runtime call that
     // may throw an exception.
     ASSERT(compiler->pending_deoptimization_env_ == NULL);
     compiler->pending_deoptimization_env_ = instruction_->env();
     compiler->GenerateCallRuntime(instruction_->token_pos(),
                                   instruction_->deopt_id(),
                                   kStackOverflowRuntimeEntry,
                                   instruction_->locs());
+
+    if (FLAG_use_osr && !compiler->is_optimizing() && instruction_->in_loop()) {
+      // In unoptimized code, record loop stack checks as possible OSR entries.
+      compiler->AddCurrentDescriptor(PcDescriptors::kOsrEntry,
+                                     instruction_->deopt_id(),
+                                     0);  // No token position.
+    }
     compiler->pending_deoptimization_env_ = NULL;
     compiler->RestoreLiveRegisters(instruction_->locs());
     __ b(exit_label());
   }
 
  private:
   CheckStackOverflowInstr* instruction_;
 };
 
 
 void CheckStackOverflowInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   __ TraceSimMsg("CheckStackOverflowInstr");
   CheckStackOverflowSlowPath* slow_path = new CheckStackOverflowSlowPath(this);
   compiler->AddSlowPathCode(slow_path);
 
   __ LoadImmediate(TMP1, Isolate::Current()->stack_limit_address());
 
   __ lw(TMP1, Address(TMP1));
   __ BranchUnsignedLessEqual(SP, TMP1, slow_path->entry_label());
-
+  if (compiler->CanOSRFunction() && in_loop()) {
+    Register temp = locs()->temp(0).reg();
+    // In unoptimized code check the usage counter to trigger OSR at loop
+    // stack checks.  Use progressively higher thresholds for more deeply
+    // nested loops to attempt to hit outer loops with OSR when possible.
+    __ LoadObject(temp, compiler->parsed_function().function());
+    intptr_t threshold =
+        FLAG_optimization_counter_threshold * (loop_depth() + 1);
+    __ lw(temp, FieldAddress(temp, Function::usage_counter_offset()));
+    __ BranchSignedGreaterEqual(temp, threshold, slow_path->entry_label());
+  }
   __ Bind(slow_path->exit_label());
 }
 
 
 static void EmitSmiShiftLeft(FlowGraphCompiler* compiler,
                              BinarySmiOpInstr* shift_left) {
   const bool is_truncating = shift_left->is_truncating();
   const LocationSummary& locs = *shift_left->locs();
   Register left = locs.in(0).reg();
   Register result = locs.out().reg();
@@ skipping 1551 matching lines @@
   compiler->GenerateCall(token_pos(),
                          &label,
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS