Refactored FlowGraphBuilder into a separate FlowGraph representation.

runtime/vm/flow_graph_allocator.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_allocator.h"
 
 #include "vm/bit_vector.h"
 #include "vm/intermediate_language.h"
 #include "vm/il_printer.h"
-#include "vm/flow_graph_builder.h"
+#include "vm/flow_graph.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/parser.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, print_ssa_liveness, false,
             "Print liveness for ssa variables.");
 DEFINE_FLAG(bool, trace_ssa_allocator, false,
             "Trace register allocation over SSA.");
 DEFINE_FLAG(bool, print_ssa_liveranges, false,
@@ skipping 28 matching lines @@
 static bool IsInstructionEndPosition(intptr_t pos) {
   return (pos & 1) == 1;
 }
 
 
 static intptr_t ToInstructionStart(intptr_t pos) {
   return (pos & ~1);
 }
 
 
-FlowGraphAllocator::FlowGraphAllocator(
-  const GrowableArray<BlockEntryInstr*>& block_order,
-  FlowGraphBuilder* builder)
-  : builder_(builder),
-    block_order_(block_order),
-    postorder_(builder->postorder_block_entries()),
-    live_out_(block_order.length()),
-    kill_(block_order.length()),
-    live_in_(block_order.length()),
-    vreg_count_(builder->current_ssa_temp_index()),
-    live_ranges_(builder->current_ssa_temp_index()),
+FlowGraphAllocator::FlowGraphAllocator(const FlowGraph& flow_graph)
+  : flow_graph_(flow_graph),
+    block_order_(flow_graph.reverse_postorder()),
+    postorder_(flow_graph.postorder()),
+    live_out_(block_order_.length()),
+    kill_(block_order_.length()),
+    live_in_(block_order_.length()),
+    vreg_count_(flow_graph.max_virtual_register_number()),
+    live_ranges_(flow_graph.max_virtual_register_number()),
     cpu_regs_(),
     blocked_cpu_regs_() {
   for (intptr_t i = 0; i < vreg_count_; i++) live_ranges_.Add(NULL);
 
   blocked_cpu_regs_[CTX] = true;
   if (TMP != kNoRegister) {
     blocked_cpu_regs_[TMP] = true;
   }
   blocked_cpu_regs_[SPREG] = true;
   blocked_cpu_regs_[FPREG] = true;
@@ skipping 418 matching lines @@
       // Skip parallel moves that we insert while processing instructions.
       if (!current->IsParallelMove()) {
         ProcessOneInstruction(block, current);
       }
       current = current->previous();
     }
 
     ConnectIncomingPhiMoves(block);
   }
 
-  const bool copied = builder_->copied_parameter_count() > 0;
-
   // Process incoming parameters.  Do this after all other instructions so
   // that safepoints for all calls have already been found.
-  const intptr_t fixed_parameters_count =
-      builder_->parsed_function().function().num_fixed_parameters();
-
   GraphEntryInstr* graph_entry = postorder_[block_count - 1]->AsGraphEntry();
   for (intptr_t i = 0; i < graph_entry->start_env()->values().length(); i++) {
     Value* val = graph_entry->start_env()->values()[i];
     if (val->IsUse()) {
       ParameterInstr* param = val->AsUse()->definition()->AsParameter();
 
       LiveRange* range = GetLiveRange(param->ssa_temp_index());
       range->AddUseInterval(graph_entry->start_pos(), graph_entry->end_pos());
       range->DefineAt(graph_entry->start_pos());
 
+      // Assert that copied and non-copied parameters are mutually exclusive.
+      // This might change in the future and, if so, the index will be wrong.
+      ASSERT(flow_graph_.copied_parameter_count() == 0 ||
+             flow_graph_.non_copied_parameter_count() == 0);
       // Slot index for the leftmost copied parameter is 0.
       intptr_t slot_index = param->index();
-      if (!copied) {
-        // Slot index for the rightmost fixed parameter is -1.
-        slot_index -= fixed_parameters_count;
-      }
+      // Slot index for the rightmost fixed parameter is -1.
+      slot_index -= flow_graph_.non_copied_parameter_count();
 
       range->set_assigned_location(Location::StackSlot(slot_index));
       range->set_spill_slot(Location::StackSlot(slot_index));
-      if (copied) {
+      if (flow_graph_.copied_parameter_count() > 0) {
         ASSERT(spill_slots_.length() == slot_index);
         spill_slots_.Add(range->End());
       }
 
       AssignSafepoints(range);
 
       range->finger()->Initialize(range);
       UsePosition* use = range->finger()->FirstRegisterBeneficialUse(
           graph_entry->start_pos());
       if (use != NULL) {
         LiveRange* tail = SplitBetween(range,
                                        graph_entry->start_pos(),
                                        use->pos());
         AddToUnallocated(tail);
       }
       ConvertAllUses(range);
-      if (copied) MarkAsObjectAtSafepoints(range);
+      if (flow_graph_.copied_parameter_count() > 0) {
+        MarkAsObjectAtSafepoints(range);
+      }
     }
   }
 }
 
 //
 // When describing shape of live ranges in comments below we are going to use
 // the following notation:
 //
 //    B    block entry
 //    g g' start and end of goto instruction
@@ skipping 177 matching lines @@
 // temporaries and output.
 void FlowGraphAllocator::ProcessOneInstruction(BlockEntryInstr* block,
                                                Instruction* current) {
   const intptr_t pos = current->lifetime_position();
   ASSERT(IsInstructionStartPosition(pos));
 
   LocationSummary* locs = current->locs();
 
   // TODO(vegorov): number of inputs must match number of input locations.
   if (locs->input_count() != current->InputCount()) {
-    builder_->Bailout("ssa allocator: number of input locations mismatch");
+    flow_graph_.Bailout("ssa allocator: number of input locations mismatch");
   }
 
   // Normalize same-as-first-input output if input is specified as
   // fixed register.
   if (locs->out().IsUnallocated() &&
       (locs->out().policy() == Location::kSameAsFirstInput) &&
       (locs->in(0).IsRegister())) {
     locs->set_out(locs->in(0));
   }
 
@@ skipping 1235 matching lines @@
 
   DiscoverLoops();
 
   BuildLiveRanges();
 
   if (FLAG_print_ssa_liveness) {
     DumpLiveness();
   }
 
   if (FLAG_print_ssa_liveranges) {
-    const Function& function = builder_->parsed_function().function();
+    const Function& function = flow_graph_.parsed_function().function();
 
     OS::Print("-- [before ssa allocator] ranges [%s] ---------\n",
               function.ToFullyQualifiedCString());
     PrintLiveRanges();
     OS::Print("----------------------------------------------\n");
 
     OS::Print("-- [before ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
-    FlowGraphPrinter printer(Function::Handle(), block_order_, true);
+    FlowGraphPrinter printer(flow_graph_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 
   AllocateCPURegisters();
 
   ResolveControlFlow();
 
   GraphEntryInstr* entry = block_order_[0]->AsGraphEntry();
   ASSERT(entry != NULL);
   entry->set_spill_slot_count(spill_slots_.length());
 
   if (FLAG_print_ssa_liveranges) {
-    const Function& function = builder_->parsed_function().function();
+    const Function& function = flow_graph_.parsed_function().function();
 
     OS::Print("-- [after ssa allocator] ranges [%s] ---------\n",
               function.ToFullyQualifiedCString());
     PrintLiveRanges();
     OS::Print("----------------------------------------------\n");
 
     OS::Print("-- [after ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
-    FlowGraphPrinter printer(Function::Handle(), block_order_, true);
+    FlowGraphPrinter printer(flow_graph_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 }
 
 
 }  // namespace dart