Make LinearizeGraph() public (and move it to nodes files)

Rationale:
It is strange that HLinearOrderIterator is defined (and visible)
in nodes.h, but clients have no way to build this order. This CL
makes the building available at the usual place.

Change-Id: Ib66f2edf6dfc8edd6b429bd4bea3ac7e37440b28
Tests: m test-art

4 files changed, 115 insertions, 115 deletions

diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 8f37236ede..9cfa89b7d0 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -460,6 +460,113 @@ GraphAnalysisResult HGraph::AnalyzeLoops() const {
   return kAnalysisSuccess;
 }
 
+static bool InSameLoop(HLoopInformation* first_loop, HLoopInformation* second_loop) {
+  return first_loop == second_loop;
+}
+
+static bool IsLoop(HLoopInformation* info) {
+  return info != nullptr;
+}
+
+static bool IsInnerLoop(HLoopInformation* outer, HLoopInformation* inner) {
+  return (inner != outer)
+      && (inner != nullptr)
+      && (outer != nullptr)
+      && inner->IsIn(*outer);
+}
+
+// Helper method to update work list for linear order.
+static void AddToListForLinearization(ArenaVector<HBasicBlock*>* worklist, HBasicBlock* block) {
+  HLoopInformation* block_loop = block->GetLoopInformation();
+  auto insert_pos = worklist->rbegin();  // insert_pos.base() will be the actual position.
+  for (auto end = worklist->rend(); insert_pos != end; ++insert_pos) {
+    HBasicBlock* current = *insert_pos;
+    HLoopInformation* current_loop = current->GetLoopInformation();
+    if (InSameLoop(block_loop, current_loop)
+        || !IsLoop(current_loop)
+        || IsInnerLoop(current_loop, block_loop)) {
+      // The block can be processed immediately.
+      break;
+    }
+  }
+  worklist->insert(insert_pos.base(), block);
+}
+
+// Helper method to validate linear order.
+static bool IsLinearOrderWellFormed(const HGraph& graph) {
+  for (HBasicBlock* header : graph.GetBlocks()) {
+    if (header == nullptr || !header->IsLoopHeader()) {
+      continue;
+    }
+    HLoopInformation* loop = header->GetLoopInformation();
+    size_t num_blocks = loop->GetBlocks().NumSetBits();
+    size_t found_blocks = 0u;
+    for (HLinearOrderIterator it(graph); !it.Done(); it.Advance()) {
+      HBasicBlock* current = it.Current();
+      if (loop->Contains(*current)) {
+        found_blocks++;
+        if (found_blocks == 1u && current != header) {
+          // First block is not the header.
+          return false;
+        } else if (found_blocks == num_blocks && !loop->IsBackEdge(*current)) {
+          // Last block is not a back edge.
+          return false;
+        }
+      } else if (found_blocks != 0u && found_blocks != num_blocks) {
+        // Blocks are not adjacent.
+        return false;
+      }
+    }
+    DCHECK_EQ(found_blocks, num_blocks);
+  }
+  return true;
+}
+
+void HGraph::Linearize() {
+  // Create a reverse post ordering with the following properties:
+  // - Blocks in a loop are consecutive,
+  // - Back-edge is the last block before loop exits.
+
+  // (1): Record the number of forward predecessors for each block. This is to
+  //      ensure the resulting order is reverse post order. We could use the
+  //      current reverse post order in the graph, but it would require making
+  //      order queries to a GrowableArray, which is not the best data structure
+  //      for it.
+  ArenaVector<uint32_t> forward_predecessors(blocks_.size(),
+                                             arena_->Adapter(kArenaAllocSsaLiveness));
+  for (HReversePostOrderIterator it(*this); !it.Done(); it.Advance()) {
+    HBasicBlock* block = it.Current();
+    size_t number_of_forward_predecessors = block->GetPredecessors().size();
+    if (block->IsLoopHeader()) {
+      number_of_forward_predecessors -= block->GetLoopInformation()->NumberOfBackEdges();
+    }
+    forward_predecessors[block->GetBlockId()] = number_of_forward_predecessors;
+  }
+
+  // (2): Following a worklist approach, first start with the entry block, and
+  //      iterate over the successors. When all non-back edge predecessors of a
+  //      successor block are visited, the successor block is added in the worklist
+  //      following an order that satisfies the requirements to build our linear graph.
+  linear_order_.reserve(GetReversePostOrder().size());
+  ArenaVector<HBasicBlock*> worklist(arena_->Adapter(kArenaAllocSsaLiveness));
+  worklist.push_back(GetEntryBlock());
+  do {
+    HBasicBlock* current = worklist.back();
+    worklist.pop_back();
+    linear_order_.push_back(current);
+    for (HBasicBlock* successor : current->GetSuccessors()) {
+      int block_id = successor->GetBlockId();
+      size_t number_of_remaining_predecessors = forward_predecessors[block_id];
+      if (number_of_remaining_predecessors == 1) {
+        AddToListForLinearization(&worklist, successor);
+      }
+      forward_predecessors[block_id] = number_of_remaining_predecessors - 1;
+    }
+  } while (!worklist.empty());
+
+  DCHECK(HasIrreducibleLoops() || IsLinearOrderWellFormed(*this));
+}
+
 void HLoopInformation::Dump(std::ostream& os) {
   os << "header: " << header_->GetBlockId() << std::endl;
   os << "pre header: " << GetPreHeader()->GetBlockId() << std::endl;
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 119b62a16b..4c6d28f0c8 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -365,6 +365,13 @@ class HGraph : public ArenaObject<kArenaAllocGraph> {
   // is a throw-catch loop, i.e. the header is a catch block.
   GraphAnalysisResult AnalyzeLoops() const;
 
+  // Computes the linear order (should be called before using HLinearOrderIterator).
+  // Linearizes the graph such that:
+  // (1): a block is always after its dominator,
+  // (2): blocks of loops are contiguous.
+  // This creates a natural and efficient ordering when visualizing live ranges.
+  void Linearize();
+
   // Iterate over blocks to compute try block membership. Needs reverse post
   // order and loop information.
   void ComputeTryBlockInformation();
diff --git a/compiler/optimizing/ssa_liveness_analysis.cc b/compiler/optimizing/ssa_liveness_analysis.cc
index a4d52d7761..9ce34aa80b 100644
--- a/compiler/optimizing/ssa_liveness_analysis.cc
+++ b/compiler/optimizing/ssa_liveness_analysis.cc
@@ -23,119 +23,11 @@
 namespace art {
 
 void SsaLivenessAnalysis::Analyze() {
-  LinearizeGraph();
+  graph_->Linearize();
   NumberInstructions();
   ComputeLiveness();
 }
 
-static bool IsLoop(HLoopInformation* info) {
-  return info != nullptr;
-}
-
-static bool InSameLoop(HLoopInformation* first_loop, HLoopInformation* second_loop) {
-  return first_loop == second_loop;
-}
-
-static bool IsInnerLoop(HLoopInformation* outer, HLoopInformation* inner) {
-  return (inner != outer)
-      && (inner != nullptr)
-      && (outer != nullptr)
-      && inner->IsIn(*outer);
-}
-
-static void AddToListForLinearization(ArenaVector<HBasicBlock*>* worklist, HBasicBlock* block) {
-  HLoopInformation* block_loop = block->GetLoopInformation();
-  auto insert_pos = worklist->rbegin();  // insert_pos.base() will be the actual position.
-  for (auto end = worklist->rend(); insert_pos != end; ++insert_pos) {
-    HBasicBlock* current = *insert_pos;
-    HLoopInformation* current_loop = current->GetLoopInformation();
-    if (InSameLoop(block_loop, current_loop)
-        || !IsLoop(current_loop)
-        || IsInnerLoop(current_loop, block_loop)) {
-      // The block can be processed immediately.
-      break;
-    }
-  }
-  worklist->insert(insert_pos.base(), block);
-}
-
-static bool IsLinearOrderWellFormed(const HGraph& graph) {
-  for (HBasicBlock* header : graph.GetBlocks()) {
-    if (header == nullptr || !header->IsLoopHeader()) {
-      continue;
-    }
-
-    HLoopInformation* loop = header->GetLoopInformation();
-    size_t num_blocks = loop->GetBlocks().NumSetBits();
-    size_t found_blocks = 0u;
-
-    for (HLinearOrderIterator it(graph); !it.Done(); it.Advance()) {
-      HBasicBlock* current = it.Current();
-      if (loop->Contains(*current)) {
-        found_blocks++;
-        if (found_blocks == 1u && current != header) {
-          // First block is not the header.
-          return false;
-        } else if (found_blocks == num_blocks && !loop->IsBackEdge(*current)) {
-          // Last block is not a back edge.
-          return false;
-        }
-      } else if (found_blocks != 0u && found_blocks != num_blocks) {
-        // Blocks are not adjacent.
-        return false;
-      }
-    }
-    DCHECK_EQ(found_blocks, num_blocks);
-  }
-
-  return true;
-}
-
-void SsaLivenessAnalysis::LinearizeGraph() {
-  // Create a reverse post ordering with the following properties:
-  // - Blocks in a loop are consecutive,
-  // - Back-edge is the last block before loop exits.
-
-  // (1): Record the number of forward predecessors for each block. This is to
-  //      ensure the resulting order is reverse post order. We could use the
-  //      current reverse post order in the graph, but it would require making
-  //      order queries to a GrowableArray, which is not the best data structure
-  //      for it.
-  ArenaVector<uint32_t> forward_predecessors(graph_->GetBlocks().size(),
-                                             graph_->GetArena()->Adapter(kArenaAllocSsaLiveness));
-  for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) {
-    HBasicBlock* block = it.Current();
-    size_t number_of_forward_predecessors = block->GetPredecessors().size();
-    if (block->IsLoopHeader()) {
-      number_of_forward_predecessors -= block->GetLoopInformation()->NumberOfBackEdges();
-    }
-    forward_predecessors[block->GetBlockId()] = number_of_forward_predecessors;
-  }
-
-  // (2): Following a worklist approach, first start with the entry block, and
-  //      iterate over the successors. When all non-back edge predecessors of a
-  //      successor block are visited, the successor block is added in the worklist
-  //      following an order that satisfies the requirements to build our linear graph.
-  graph_->linear_order_.reserve(graph_->GetReversePostOrder().size());
-  ArenaVector<HBasicBlock*> worklist(graph_->GetArena()->Adapter(kArenaAllocSsaLiveness));
-  worklist.push_back(graph_->GetEntryBlock());
-  do {
-    HBasicBlock* current = worklist.back();
-    worklist.pop_back();
-    graph_->linear_order_.push_back(current);
-    for (HBasicBlock* successor : current->GetSuccessors()) {
-      int block_id = successor->GetBlockId();
-      size_t number_of_remaining_predecessors = forward_predecessors[block_id];
-      if (number_of_remaining_predecessors == 1) {
-        AddToListForLinearization(&worklist, successor);
-      }
-      forward_predecessors[block_id] = number_of_remaining_predecessors - 1;
-    }
-  } while (!worklist.empty());
-
-  DCHECK(graph_->HasIrreducibleLoops() || IsLinearOrderWellFormed(*graph_));
-}
-
 void SsaLivenessAnalysis::NumberInstructions() {
   int ssa_index = 0;
   size_t lifetime_position = 0;
diff --git a/compiler/optimizing/ssa_liveness_analysis.h b/compiler/optimizing/ssa_liveness_analysis.h
index 0be16118b1..b62bf4e5f9 100644
--- a/compiler/optimizing/ssa_liveness_analysis.h
+++ b/compiler/optimizing/ssa_liveness_analysis.h
@@ -1186,12 +1186,6 @@ class SsaLivenessAnalysis : public ValueObject {
   static constexpr const char* kLivenessPassName = "liveness";
 
  private:
-  // Linearize the graph so that:
-  // (1): a block is always after its dominator,
-  // (2): blocks of loops are contiguous.
-  // This creates a natural and efficient ordering when visualizing live ranges.
-  void LinearizeGraph();
-
   // Give an SSA number to each instruction that defines a value used by another instruction,
   // and setup the lifetime information of each instruction and block.
   void NumberInstructions();