Deoptimization support in inlined code.

runtime/vm/flow_graph_inliner.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/flow_graph_inliner.h"
 
+#include "vm/compiler.h"
 #include "vm/flags.h"
 #include "vm/flow_graph.h"
 #include "vm/flow_graph_builder.h"
+#include "vm/flow_graph_optimizer.h"
+#include "vm/intrinsifier.h"

[Kevin Millikin (Google), 2012/09/18 11:01:55]

I think we try to keep these sorted according to M-x sort-lines (e.g., intrin...
after il_pri...").

[zerny-google, 2012/09/18 11:53:07]

Thanks again.

 #include "vm/il_printer.h"
 #include "vm/longjump.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, trace_inlining, false, "Trace inlining");
 DEFINE_FLAG(charp, inlining_filter, NULL, "Inline only in named function");
 DECLARE_FLAG(bool, print_flow_graph);
+DECLARE_FLAG(bool, deoptimization_counter_threshold);
 
 #define TRACE_INLINING(statement)                                              \
   do {                                                                         \
     if (FLAG_trace_inlining) statement;                                        \
   } while (false)
 
 
 class CallSiteInliner : public FlowGraphVisitor {
  public:
   explicit CallSiteInliner(FlowGraph* flow_graph)
       : FlowGraphVisitor(flow_graph->postorder()),
         caller_graph_(flow_graph),
         next_ssa_temp_index_(flow_graph->max_virtual_register_number()),
         inlined_(false) { }
 
   bool TryInlining(const Function& function,
                    GrowableArray<Value*>* arguments,
                    Definition* call) {
     TRACE_INLINING(OS::Print("  => %s\n", function.ToCString()));
 
     // Abort if the callee has optional parameters.
     if (function.HasOptionalParameters()) {
       TRACE_INLINING(OS::Print("     Bailout: optional parameters\n"));
       return false;
     }
 
     // Assuming no optional parameters the actual/formal count should match.
     ASSERT(arguments->length() == function.num_fixed_parameters());
 
+    // Abort if the callee has an intrinsic translation.
+    if (Intrinsifier::CanIntrinsify(function)) {
+      TRACE_INLINING(OS::Print("     Bailout: can intrinsify\n"));
+      return false;
+    }
+
     Isolate* isolate = Isolate::Current();
     // Save and clear IC data.
     const Array& old_ic_data = Array::Handle(isolate->ic_data_array());
     isolate->set_ic_data_array(Array::null());
+    // Save and clear deopt id.
+    const intptr_t prev_deopt_id = isolate->deopt_id();

[Kevin Millikin (Google), 2012/09/18 11:01:55]

It distracts me that we have old_ic_data and prev_deopt_id.  They should both be
old or both be prev.

[zerny-google, 2012/09/18 11:53:07]

Done.

+    isolate->set_deopt_id(0);
     // Install bailout jump.
     LongJump* base = isolate->long_jump_base();
     LongJump jump;
     isolate->set_long_jump_base(&jump);
     if (setjmp(*jump.Set()) == 0) {
       // Parse the callee function.
       ParsedFunction parsed_function(function);
       Parser::ParseFunction(&parsed_function);
       parsed_function.AllocateVariables();
-      FlowGraphBuilder builder(parsed_function);
+
+      // Load IC data for the callee.
+      if ((function.deoptimization_counter() <
+           FLAG_deoptimization_counter_threshold) &&
+          function.HasCode()) {
+        const Code& unoptimized_code =
+            Code::Handle(function.unoptimized_code());
+        isolate->set_ic_data_array(
+            Compiler::ExtractTypeFeedbackArray(unoptimized_code));
+      }
 
       // Build the callee graph.
+      FlowGraphBuilder builder(parsed_function);
       FlowGraph* callee_graph =
           builder.BuildGraph(FlowGraphBuilder::kValueContext);
 
       // Abort if the callee graph contains control flow.
       if (callee_graph->preorder().length() != 2) {
         isolate->set_long_jump_base(base);
         isolate->set_ic_data_array(old_ic_data.raw());
         TRACE_INLINING(OS::Print("     Bailout: control flow\n"));
         return false;
       }
 
+      // Compute SSA on the callee graph. (catching bailouts)

[Kevin Millikin (Google), 2012/09/18 11:01:55]

Format as a complete sentence: "Compute SSA on the callee graph, catching
bailouts."

[zerny-google, 2012/09/18 11:53:07]

Done.

+      callee_graph->ComputeSSA(next_ssa_temp_index_);
+      callee_graph->ComputeUseLists();
+
+      // TODO(zerny): Do optimization passes on the callee graph.

[Kevin Millikin (Google), 2012/09/18 11:01:55]

"Do more optimization...."

[zerny-google, 2012/09/18 11:53:07]

Done.

+      FlowGraphOptimizer optimizer(callee_graph);
+      optimizer.ApplyICData();
+      callee_graph->ComputeUseLists();
+
       if (FLAG_trace_inlining && FLAG_print_flow_graph) {
-        OS::Print("Callee graph before SSA %s\n",
+        OS::Print("Callee graph for inlining %s\n",
                   parsed_function.function().ToFullyQualifiedCString());
         FlowGraphPrinter printer(*callee_graph);
         printer.PrintBlocks();
       }
 
-      // Compute SSA on the callee graph. (catching bailouts)
-      callee_graph->ComputeSSA(next_ssa_temp_index_);
-
-      if (FLAG_trace_inlining && FLAG_print_flow_graph) {
-        OS::Print("Callee graph after SSA %s\n",
-                  parsed_function.function().ToFullyQualifiedCString());
-        FlowGraphPrinter printer(*callee_graph);
-        printer.PrintBlocks();
-      }
-
-      callee_graph->ComputeUseLists();
-
-      // TODO(zerny): Do optimization passes on the callee graph.
-
       // TODO(zerny): If result is more than size threshold then abort.
 
       // TODO(zerny): If effort is less than threshold then inline recursively.
 
       // Plug result in the caller graph.
       caller_graph_->InlineCall(call, callee_graph);
       next_ssa_temp_index_ = caller_graph_->max_virtual_register_number();
 
-      // Remove (all) push arguments of the call.
+      // Check that inlining maintains use lists.
+      DEBUG_ASSERT(caller_graph_->ValidateUseLists());
+
+      // Remove push arguments of the call.
       for (intptr_t i = 0; i < call->ArgumentCount(); ++i) {
         PushArgumentInstr* push = call->ArgumentAt(i);
         push->ReplaceUsesWith(push->value()->definition());
         push->RemoveFromGraph();
       }
 
-      // Replace all the formal parameters with the actuals.
+      // Replace formal parameters with actuals.
       for (intptr_t i = 0; i < arguments->length(); ++i) {
         Value* val = callee_graph->graph_entry()->start_env()->ValueAt(i);
         ParameterInstr* param = val->definition()->AsParameter();
         ASSERT(param != NULL);
         param->ReplaceUsesWith((*arguments)[i]->definition());
       }
 
       // Replace callee's null constant with caller's null constant.
       callee_graph->graph_entry()->constant_null()->ReplaceUsesWith(
           caller_graph_->graph_entry()->constant_null());
 
       TRACE_INLINING(OS::Print("     Success\n"));
 
       // Build succeeded so we restore the bailout jump.
       inlined_ = true;
       isolate->set_long_jump_base(base);
+      isolate->set_deopt_id(prev_deopt_id);
       isolate->set_ic_data_array(old_ic_data.raw());
       return true;
     } else {
       Error& error = Error::Handle();
       error = isolate->object_store()->sticky_error();
       isolate->object_store()->clear_sticky_error();
       isolate->set_long_jump_base(base);
+      isolate->set_deopt_id(prev_deopt_id);
       isolate->set_ic_data_array(old_ic_data.raw());
       TRACE_INLINING(OS::Print("     Bailout: %s\n", error.ToErrorCString()));
       return false;
     }
   }
 
   void VisitClosureCall(ClosureCallInstr* call) {
     TRACE_INLINING(OS::Print("  ClosureCall\n"));
     // Find the closure of the callee.
     ASSERT(call->ArgumentCount() > 0);
@@ skipping 46 matching lines @@
 
 
 void FlowGraphInliner::Inline() {
   if ((FLAG_inlining_filter != NULL) &&
       (strstr(flow_graph_->
               parsed_function().function().ToFullyQualifiedCString(),
               FLAG_inlining_filter) == NULL)) {
     return;
   }
 
+  TRACE_INLINING(OS::Print(
+      "Inlining calls in %s\n",
+      flow_graph_->parsed_function().function().ToCString()));
+
   if (FLAG_trace_inlining && FLAG_print_flow_graph) {
     OS::Print("Before Inlining of %s\n", flow_graph_->
               parsed_function().function().ToFullyQualifiedCString());
     FlowGraphPrinter printer(*flow_graph_);
     printer.PrintBlocks();
   }
 
-  TRACE_INLINING(OS::Print(
-      "Inlining calls in %s\n",
-      flow_graph_->parsed_function().function().ToCString()));
   CallSiteInliner inliner(flow_graph_);
   inliner.VisitBlocks();
 
   if (inliner.inlined()) {
     if (FLAG_trace_inlining && FLAG_print_flow_graph) {
       OS::Print("After Inlining of %s\n", flow_graph_->
                 parsed_function().function().ToFullyQualifiedCString());
       FlowGraphPrinter printer(*flow_graph_);
       printer.PrintBlocks();
     }
   }
 }
 
 }  // namespace dart