Sink InstructionSelect() out of each target into SDISel, and rename it

DoInstructionSelection.  Inline "SelectRoot" into it from DAGISelHeader.
Sink some other stuff out of DAGISelHeader into SDISel.

Eliminate the various 'Indent' stuff from various targets, which dates
to when isel was recursive.

 17 files changed, 114 insertions(+), 430 deletions(-)



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97555 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 13 insertions, 96 deletions

diff --git a/include/llvm/CodeGen/DAGISelHeader.h b/include/llvm/CodeGen/DAGISelHeader.h
index 4a3d70f..86c86e9 100644
--- a/include/llvm/CodeGen/DAGISelHeader.h
+++ b/include/llvm/CodeGen/DAGISelHeader.h
@@ -21,97 +21,6 @@
 #ifndef LLVM_CODEGEN_DAGISEL_HEADER_H
 #define LLVM_CODEGEN_DAGISEL_HEADER_H
 
-/// ISelPosition - Node iterator marking the current position of
-/// instruction selection as it procedes through the topologically-sorted
-/// node list.
-SelectionDAG::allnodes_iterator ISelPosition;
-
-/// ISelUpdater - helper class to handle updates of the 
-/// instruciton selection graph.
-class VISIBILITY_HIDDEN ISelUpdater : public SelectionDAG::DAGUpdateListener {
-  SelectionDAG::allnodes_iterator &ISelPosition;
-public:
-  explicit ISelUpdater(SelectionDAG::allnodes_iterator &isp)
-    : ISelPosition(isp) {}
-  
-  /// NodeDeleted - Handle nodes deleted from the graph. If the
-  /// node being deleted is the current ISelPosition node, update
-  /// ISelPosition.
-  ///
-  virtual void NodeDeleted(SDNode *N, SDNode *E) {
-    if (ISelPosition == SelectionDAG::allnodes_iterator(N))
-      ++ISelPosition;
-  }
-
-  /// NodeUpdated - Ignore updates for now.
-  virtual void NodeUpdated(SDNode *N) {}
-};
-
-/// ReplaceUses - replace all uses of the old node F with the use
-/// of the new node T.
-DISABLE_INLINE void ReplaceUses(SDValue F, SDValue T) {
-  ISelUpdater ISU(ISelPosition);
-  CurDAG->ReplaceAllUsesOfValueWith(F, T, &ISU);
-}
-
-/// ReplaceUses - replace all uses of the old nodes F with the use
-/// of the new nodes T.
-DISABLE_INLINE void ReplaceUses(const SDValue *F, const SDValue *T,
-                                unsigned Num) {
-  ISelUpdater ISU(ISelPosition);
-  CurDAG->ReplaceAllUsesOfValuesWith(F, T, Num, &ISU);
-}
-
-/// ReplaceUses - replace all uses of the old node F with the use
-/// of the new node T.
-DISABLE_INLINE void ReplaceUses(SDNode *F, SDNode *T) {
-  ISelUpdater ISU(ISelPosition);
-  CurDAG->ReplaceAllUsesWith(F, T, &ISU);
-}
-
-/// SelectRoot - Top level entry to DAG instruction selector.
-/// Selects instructions starting at the root of the current DAG.
-void SelectRoot(SelectionDAG &DAG) {
-  SelectRootInit();
-
-  // Create a dummy node (which is not added to allnodes), that adds
-  // a reference to the root node, preventing it from being deleted,
-  // and tracking any changes of the root.
-  HandleSDNode Dummy(CurDAG->getRoot());
-  ISelPosition = SelectionDAG::allnodes_iterator(CurDAG->getRoot().getNode());
-  ++ISelPosition;
-
-  // The AllNodes list is now topological-sorted. Visit the
-  // nodes by starting at the end of the list (the root of the
-  // graph) and preceding back toward the beginning (the entry
-  // node).
-  while (ISelPosition != CurDAG->allnodes_begin()) {
-    SDNode *Node = --ISelPosition;
-    // Skip dead nodes. DAGCombiner is expected to eliminate all dead nodes,
-    // but there are currently some corner cases that it misses. Also, this
-    // makes it theoretically possible to disable the DAGCombiner.
-    if (Node->use_empty())
-      continue;
-
-    SDNode *ResNode = Select(Node);
-    
-    // If node should not be replaced, continue with the next one.
-    if (ResNode == Node)
-      continue;
-    // Replace node.
-    if (ResNode)
-      ReplaceUses(Node, ResNode);
-
-    // If after the replacement this node is not used any more,
-    // remove this dead node.
-    if (Node->use_empty()) { // Don't delete EntryToken, etc.
-      ISelUpdater ISU(ISelPosition);
-      CurDAG->RemoveDeadNode(Node, &ISU);
-    }
-  }
-
-  CurDAG->setRoot(Dummy.getValue());
-}
 
 
 #endif /* LLVM_CODEGEN_DAGISEL_HEADER_H */
diff --git a/include/llvm/CodeGen/SelectionDAGISel.h b/include/llvm/CodeGen/SelectionDAGISel.h
index c43eede..a72fa59 100644
--- a/include/llvm/CodeGen/SelectionDAGISel.h
+++ b/include/llvm/CodeGen/SelectionDAGISel.h
@@ -68,12 +68,18 @@ public:
   unsigned MakeReg(EVT VT);
 
   virtual void EmitFunctionEntryCode(Function &Fn, MachineFunction &MF) {}
-  virtual void InstructionSelect() = 0;
   
-  void SelectRootInit() {
-    DAGSize = CurDAG->AssignTopologicalOrder();
-  }
-
+  /// PreprocessISelDAG - This hook allows targets to hack on the graph before
+  /// instruction selection starts.
+  virtual void PreprocessISelDAG() {}
+  
+  /// PostprocessISelDAG() - This hook allows the target to hack on the graph
+  /// right after selection.
+  virtual void PostprocessISelDAG() {}
+  
+  /// Select - Main hook targets implement to select a node.
+  virtual SDNode *Select(SDNode *N) = 0;
+  
   /// SelectInlineAsmMemoryOperand - Select the specified address as a target
   /// addressing mode, according to the specified constraint code.  If this does
   /// not match or is not implemented, return true.  The resultant operands
@@ -268,6 +274,8 @@ protected:
   void CannotYetSelectIntrinsic(SDNode *N);
 
 private:
+  void DoInstructionSelection();
+  
   void SelectAllBasicBlocks(Function &Fn, MachineFunction &MF,
                             MachineModuleInfo *MMI,
                             DwarfWriter *DW,