Let's start another backend :)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75909 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/SystemZ/SystemZISelDAGToDAG.cpp

@@ -0,0 +1,129 @@
+//==-- SystemZISelDAGToDAG.cpp - A dag to dag inst selector for SystemZ ---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines an instruction selector for the SystemZ target.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SystemZ.h"
+#include "SystemZISelLowering.h"
+#include "SystemZTargetMachine.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Function.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/CallingConv.h"
+#include "llvm/Constants.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/SelectionDAGISel.h"
+#include "llvm/Target/TargetLowering.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+using namespace llvm;
+
+/// SystemZDAGToDAGISel - SystemZ specific code to select SystemZ machine
+/// instructions for SelectionDAG operations.
+///
+namespace {
+  class SystemZDAGToDAGISel : public SelectionDAGISel {
+    SystemZTargetLowering &Lowering;
+    const SystemZSubtarget &Subtarget;
+
+  public:
+    SystemZDAGToDAGISel(SystemZTargetMachine &TM, CodeGenOpt::Level OptLevel)
+      : SelectionDAGISel(TM, OptLevel),
+        Lowering(*TM.getTargetLowering()),
+        Subtarget(*TM.getSubtargetImpl()) { }
+
+    virtual void InstructionSelect();
+
+    virtual const char *getPassName() const {
+      return "SystemZ DAG->DAG Pattern Instruction Selection";
+    }
+
+    // Include the pieces autogenerated from the target description.
+  #include "SystemZGenDAGISel.inc"
+
+  private:
+    SDNode *Select(SDValue Op);
+
+  #ifndef NDEBUG
+    unsigned Indent;
+  #endif
+  };
+}  // end anonymous namespace
+
+/// createSystemZISelDag - This pass converts a legalized DAG into a
+/// SystemZ-specific DAG, ready for instruction scheduling.
+///
+FunctionPass *llvm::createSystemZISelDag(SystemZTargetMachine &TM,
+                                        CodeGenOpt::Level OptLevel) {
+  return new SystemZDAGToDAGISel(TM, OptLevel);
+}
+
+
+/// InstructionSelect - This callback is invoked by
+/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
+void SystemZDAGToDAGISel::InstructionSelect() {
+  DEBUG(BB->dump());
+
+  // Codegen the basic block.
+#ifndef NDEBUG
+  DOUT << "===== Instruction selection begins:\n";
+  Indent = 0;
+#endif
+  SelectRoot(*CurDAG);
+#ifndef NDEBUG
+  DOUT << "===== Instruction selection ends:\n";
+#endif
+
+  CurDAG->RemoveDeadNodes();
+}
+
+SDNode *SystemZDAGToDAGISel::Select(SDValue Op) {
+  SDNode *Node = Op.getNode();
+  DebugLoc dl = Op.getDebugLoc();
+
+  // Dump information about the Node being selected
+  #ifndef NDEBUG
+  DOUT << std::string(Indent, ' ') << "Selecting: ";
+  DEBUG(Node->dump(CurDAG));
+  DOUT << "\n";
+  Indent += 2;
+  #endif
+
+  // If we have a custom node, we already have selected!
+  if (Node->isMachineOpcode()) {
+    #ifndef NDEBUG
+    DOUT << std::string(Indent-2, ' ') << "== ";
+    DEBUG(Node->dump(CurDAG));
+    DOUT << "\n";
+    Indent -= 2;
+    #endif
+    return NULL;
+  }
+
+  // Select the default instruction
+  SDNode *ResNode = SelectCode(Op);
+
+  #ifndef NDEBUG
+  DOUT << std::string(Indent-2, ' ') << "=> ";
+  if (ResNode == NULL || ResNode == Op.getNode())
+    DEBUG(Op.getNode()->dump(CurDAG));
+  else
+    DEBUG(ResNode->dump(CurDAG));
+  DOUT << "\n";
+  Indent -= 2;
+  #endif
+
+  return ResNode;
+}