Inlining of static calls with trivial function bodies.

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/flags.h"
+#include "vm/flow_graph.h"
+#include "vm/flow_graph_builder.h"
+#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);
+
+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) { }
+
+  void TryInlining(const Function& function,
+                   GrowableArray<Value*>* arguments,
+                   StaticCallComp* comp,  // TODO(zerny): Generalize to calls.
+                   BindInstr* instr) {
+    // Abort if the callee has named parameters.
+    if (function.num_optional_parameters() > 0) {
+      if (FLAG_trace_inlining) {
+        OS::Print("Inline aborted %s\nReason: optional parameters\n",
+                  function.ToFullyQualifiedCString());
+      }
+      return;
+    }
+
+    // Assuming no optional parameters the actual/formal count should match.
+    ASSERT(arguments->length() == function.num_fixed_parameters());
+
+    // Parse the callee function.
+    ParsedFunction parsed_function(function);
+    Parser::ParseFunction(&parsed_function);
+    FlowGraphBuilder builder(parsed_function);
+
+    // Install bailout jump.
+    Isolate* isolate = Isolate::Current();
+    LongJump* base = isolate->long_jump_base();
+    LongJump jump;
+    isolate->set_long_jump_base(&jump);
+    if (setjmp(*jump.Set()) == 0) {
+      // Build the callee graph.
+      FlowGraph* callee_graph =
+          builder.BuildGraphForInlining(FlowGraphBuilder::kValueContext);
+
+      // Abort if the callee graph contains control flow.
+      if (callee_graph->preorder().length() != 2) {
+        isolate->set_long_jump_base(base);
+        if (FLAG_trace_inlining) {
+          OS::Print("Inline aborted %s\nReason: control flow\n",
+                    parsed_function.function().ToFullyQualifiedCString());
+        }
+        return;
+      }
+
+      if (FLAG_trace_inlining && FLAG_print_flow_graph) {
+        OS::Print("Callee graph before SSA %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_);
+
+      // Build succeeded so we restore the bailout jump.
+      isolate->set_long_jump_base(base);
+
+      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(instr, comp, callee_graph);
+      next_ssa_temp_index_ = caller_graph_->max_virtual_register_number();
+
+      // Replace all the formal parameters with the actuals.
+      for (intptr_t i = 0; i < arguments->length(); ++i) {
+        Value* val = callee_graph->graph_entry()->start_env()->values()[i];
+        ASSERT(val != NULL && val->IsUse());
+        ParameterInstr* param = val->AsUse()->definition()->AsParameter();
+        ASSERT(param != NULL);
+        param->ReplaceUsesWith((*arguments)[i]->AsUse()->definition());
+      }
+
+      inlined_ = true;
+      if (FLAG_trace_inlining) {
+        OS::Print("Inlined %s\n", function.ToFullyQualifiedCString());
+      }
+    } else {
+      Error& error = Error::Handle();
+      error = isolate->object_store()->sticky_error();
+      isolate->object_store()->clear_sticky_error();
+      isolate->set_long_jump_base(base);
+      if (FLAG_trace_inlining) {
+        OS::Print("Inline aborted for %s\nReason: %s\n",
+                  parsed_function.function().ToFullyQualifiedCString(),
+                  error.ToErrorCString());
+      }
+    }
+  }
+
+  void VisitBind(BindInstr* instr) {
+    instr->computation()->Accept(this, instr);
+  }
+
+  void VisitStaticCall(StaticCallComp* comp, BindInstr* instr) {
+    if (FLAG_trace_inlining) OS::Print("Static call\n");
+    GrowableArray<Value*> arguments(comp->ArgumentCount());
+    for (int i = 0; i < comp->ArgumentCount(); ++i) {
+      arguments.Add(comp->ArgumentAt(i)->value());
+    }
+    TryInlining(comp->function(), &arguments, comp, instr);
+  }
+
+  bool preformed_inlining() const { return inlined_; }
+
+ private:
+  FlowGraph* caller_graph_;
+  intptr_t next_ssa_temp_index_;
+  bool inlined_;
+};
+
+
+void FlowGraphInliner::Inline() {
+  if ((FLAG_inlining_filter != NULL) &&
+      (strstr(flow_graph_->
+              parsed_function().function().ToFullyQualifiedCString(),
+              FLAG_inlining_filter) == NULL)) {
+    return;
+  }
+
+  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();
+  }
+
+  CallSiteInliner inliner(flow_graph_);
+  inliner.VisitBlocks();
+
+  if (inliner.preformed_inlining()) {
+    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