Collect edge count profiling data and reorder basic blocks.

runtime/vm/compiler.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/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
+#include "vm/block_scheduler.h"
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/deopt_instructions.h"
 #include "vm/exceptions.h"
 #include "vm/flags.h"
 #include "vm/flow_graph.h"
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 25 matching lines @@
     "Do loop invariant code motion.");
 DEFINE_FLAG(bool, propagate_types, true, "Do static type propagation.");
 DEFINE_FLAG(bool, allocation_sinking, true,
     "attempt to sink temporary allocations to side exits");
 DEFINE_FLAG(int, deoptimization_counter_threshold, 16,
     "How many times we allow deoptimization before we disallow optimization.");
 DEFINE_FLAG(int, deoptimization_counter_licm_threshold, 8,
     "How many times we allow deoptimization before we disable LICM.");
 DEFINE_FLAG(bool, use_inlining, true, "Enable call-site inlining");
 DEFINE_FLAG(bool, range_analysis, true, "Enable range analysis");
+DEFINE_FLAG(bool, reorder_basic_blocks, true, "Enable basic-block reordering.");
 DEFINE_FLAG(bool, verify_compiler, false,
     "Enable compiler verification assertions");
 DECLARE_FLAG(bool, print_flow_graph);
 DECLARE_FLAG(bool, print_flow_graph_optimized);
 DECLARE_FLAG(bool, trace_failed_optimization_attempts);
 
 // Compile a function. Should call only if the function has not been compiled.
 //   Arg0: function object.
 DEFINE_RUNTIME_ENTRY(CompileFunction, 1) {
   ASSERT(arguments.ArgCount() == kCompileFunctionRuntimeEntry.argument_count());
@@ skipping 233 matching lines @@
 
       if (FLAG_print_flow_graph ||
           (optimized && FLAG_print_flow_graph_optimized)) {
         if (osr_id == Isolate::kNoDeoptId) {
           FlowGraphPrinter::PrintGraph("Before Optimizations", flow_graph);
         } else {
           FlowGraphPrinter::PrintGraph("For OSR", flow_graph);
         }
       }
 
+      BlockScheduler block_scheduler(flow_graph);
+      if (optimized && FLAG_reorder_basic_blocks) {
+        block_scheduler.AssignEdgeWeights();
+      }
+
       if (optimized) {
         TimerScope timer(FLAG_compiler_stats,
                          &CompilerStats::ssa_timer,
                          isolate);
         // Transform to SSA (virtual register 0 and no inlining arguments).
         flow_graph->ComputeSSA(0, NULL);
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
         if (FLAG_print_flow_graph || FLAG_print_flow_graph_optimized) {
           FlowGraphPrinter::PrintGraph("After SSA", flow_graph);
         }
       }
 
-
       // Collect all instance fields that are loaded in the graph and
       // have non-generic type feedback attached to them that can
       // potentially affect optimizations.
       GrowableArray<const Field*> guarded_fields(10);
       if (optimized) {
         TimerScope timer(FLAG_compiler_stats,
                          &CompilerStats::graphoptimizer_timer,
                          isolate);
 
         FlowGraphOptimizer optimizer(flow_graph, &guarded_fields);
@@ skipping 166 matching lines @@
           // Remove all MaterializeObject instructions inserted by allocation
           // sinking from the flow graph and let them float on the side
           // referenced only from environments. Register allocator will consider
           // them as part of a deoptimization environment.
           sinking->DetachMaterializations();
         }
 
         // Perform register allocation on the SSA graph.
         FlowGraphAllocator allocator(*flow_graph);
         allocator.AllocateRegisters();
+        if (FLAG_reorder_basic_blocks) block_scheduler.ReorderBlocks();
 
         if (FLAG_print_flow_graph || FLAG_print_flow_graph_optimized) {
           FlowGraphPrinter::PrintGraph("After Optimizations", flow_graph);
         }
       }
 
       Assembler assembler(use_far_branches);
-      FlowGraphCompiler graph_compiler(&assembler,
-                                       *flow_graph,
-                                       optimized);
+      FlowGraphCompiler graph_compiler(&assembler, flow_graph, optimized);
       {
         TimerScope timer(FLAG_compiler_stats,
                          &CompilerStats::graphcompiler_timer,
                          isolate);
         graph_compiler.CompileGraph();
       }
       {
         TimerScope timer(FLAG_compiler_stats,
                          &CompilerStats::codefinalizer_timer,
                          isolate);
@@ skipping 392 matching lines @@
       Object::Handle(isolate->object_store()->sticky_error());
     isolate->object_store()->clear_sticky_error();
     isolate->set_long_jump_base(base);
     return result.raw();
   }
   UNREACHABLE();
   return Object::null();
 }
 
 }  // namespace dart