Use const qualifiers with TargetLowering. This eliminates several

const_casts, and it reinforces the design of the Target classes being
immutable.

SelectionDAGISel::IsLegalToFold is now a static member function, because
PIC16 uses it in an unconventional way. There is more room for API
cleanup here.

And PIC16's AsmPrinter no longer uses TargetLowering.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101635 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 19 insertions, 17 deletions

diff --git a/lib/Target/Alpha/AlphaISelDAGToDAG.cpp b/lib/Target/Alpha/AlphaISelDAGToDAG.cpp
index 995e6ac..d526dc0 100644
--- a/lib/Target/Alpha/AlphaISelDAGToDAG.cpp
+++ b/lib/Target/Alpha/AlphaISelDAGToDAG.cpp
@@ -14,7 +14,6 @@
 
 #include "Alpha.h"
 #include "AlphaTargetMachine.h"
-#include "AlphaISelLowering.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
diff --git a/lib/Target/Alpha/AlphaISelLowering.cpp b/lib/Target/Alpha/AlphaISelLowering.cpp
index aab25df..ec845d0 100644
--- a/lib/Target/Alpha/AlphaISelLowering.cpp
+++ b/lib/Target/Alpha/AlphaISelLowering.cpp
@@ -226,7 +226,7 @@ AlphaTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
                                const SmallVectorImpl<ISD::OutputArg> &Outs,
                                const SmallVectorImpl<ISD::InputArg> &Ins,
                                DebugLoc dl, SelectionDAG &DAG,
-                               SmallVectorImpl<SDValue> &InVals) {
+                               SmallVectorImpl<SDValue> &InVals) const {
   // Alpha target does not yet support tail call optimization.
   isTailCall = false;
 
@@ -343,7 +343,7 @@ AlphaTargetLowering::LowerCallResult(SDValue Chain, SDValue InFlag,
                                      CallingConv::ID CallConv, bool isVarArg,
                                      const SmallVectorImpl<ISD::InputArg> &Ins,
                                      DebugLoc dl, SelectionDAG &DAG,
-                                     SmallVectorImpl<SDValue> &InVals) {
+                                     SmallVectorImpl<SDValue> &InVals) const {
 
   // Assign locations to each value returned by this call.
   SmallVector<CCValAssign, 16> RVLocs;
@@ -386,7 +386,8 @@ AlphaTargetLowering::LowerFormalArguments(SDValue Chain,
                                           const SmallVectorImpl<ISD::InputArg>
                                             &Ins,
                                           DebugLoc dl, SelectionDAG &DAG,
-                                          SmallVectorImpl<SDValue> &InVals) {
+                                          SmallVectorImpl<SDValue> &InVals)
+                                            const {
 
   MachineFunction &MF = DAG.getMachineFunction();
   MachineFrameInfo *MFI = MF.getFrameInfo();
@@ -469,7 +470,7 @@ SDValue
 AlphaTargetLowering::LowerReturn(SDValue Chain,
                                  CallingConv::ID CallConv, bool isVarArg,
                                  const SmallVectorImpl<ISD::OutputArg> &Outs,
-                                 DebugLoc dl, SelectionDAG &DAG) {
+                                 DebugLoc dl, SelectionDAG &DAG) const {
 
   SDValue Copy = DAG.getCopyToReg(Chain, dl, Alpha::R26,
                                   DAG.getNode(AlphaISD::GlobalRetAddr,
@@ -527,7 +528,8 @@ AlphaTargetLowering::LowerReturn(SDValue Chain,
 }
 
 void AlphaTargetLowering::LowerVAARG(SDNode *N, SDValue &Chain,
-                                     SDValue &DataPtr, SelectionDAG &DAG) {
+                                     SDValue &DataPtr,
+                                     SelectionDAG &DAG) const {
   Chain = N->getOperand(0);
   SDValue VAListP = N->getOperand(1);
   const Value *VAListS = cast<SrcValueSDNode>(N->getOperand(2))->getValue();
@@ -558,7 +560,8 @@ void AlphaTargetLowering::LowerVAARG(SDNode *N, SDValue &Chain,
 
 /// LowerOperation - Provide custom lowering hooks for some operations.
 ///
-SDValue AlphaTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) {
+SDValue AlphaTargetLowering::LowerOperation(SDValue Op,
+                                            SelectionDAG &DAG) const {
   DebugLoc dl = Op.getDebugLoc();
   switch (Op.getOpcode()) {
   default: llvm_unreachable("Wasn't expecting to be able to lower this!");
@@ -756,7 +759,7 @@ SDValue AlphaTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) {
 
 void AlphaTargetLowering::ReplaceNodeResults(SDNode *N,
                                              SmallVectorImpl<SDValue>&Results,
-                                             SelectionDAG &DAG) {
+                                             SelectionDAG &DAG) const {
   DebugLoc dl = N->getDebugLoc();
   assert(N->getValueType(0) == MVT::i32 &&
          N->getOpcode() == ISD::VAARG &&
diff --git a/lib/Target/Alpha/AlphaISelLowering.h b/lib/Target/Alpha/AlphaISelLowering.h
index b49aa9a..6919c38 100644
--- a/lib/Target/Alpha/AlphaISelLowering.h
+++ b/lib/Target/Alpha/AlphaISelLowering.h
@@ -68,13 +68,13 @@ namespace llvm {
 
     /// LowerOperation - Provide custom lowering hooks for some operations.
     ///
-    virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG);
+    virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const;
 
     /// ReplaceNodeResults - Replace the results of node with an illegal result
     /// type with new values built out of custom code.
     ///
     virtual void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue>&Results,
-                                    SelectionDAG &DAG);
+                                    SelectionDAG &DAG) const;
 
     // Friendly names for dumps
     const char *getTargetNodeName(unsigned Opcode) const;
@@ -83,7 +83,7 @@ namespace llvm {
                             CallingConv::ID CallConv, bool isVarArg,
                             const SmallVectorImpl<ISD::InputArg> &Ins,
                             DebugLoc dl, SelectionDAG &DAG,
-                            SmallVectorImpl<SDValue> &InVals);
+                            SmallVectorImpl<SDValue> &InVals) const;
 
     ConstraintType getConstraintType(const std::string &Constraint) const;
 
@@ -108,14 +108,14 @@ namespace llvm {
   private:
     // Helpers for custom lowering.
     void LowerVAARG(SDNode *N, SDValue &Chain, SDValue &DataPtr,
-                    SelectionDAG &DAG);
+                    SelectionDAG &DAG) const;
 
     virtual SDValue
       LowerFormalArguments(SDValue Chain,
                            CallingConv::ID CallConv, bool isVarArg,
                            const SmallVectorImpl<ISD::InputArg> &Ins,
                            DebugLoc dl, SelectionDAG &DAG,
-                           SmallVectorImpl<SDValue> &InVals);
+                           SmallVectorImpl<SDValue> &InVals) const;
 
     virtual SDValue
       LowerCall(SDValue Chain, SDValue Callee,
@@ -123,13 +123,13 @@ namespace llvm {
                 const SmallVectorImpl<ISD::OutputArg> &Outs,
                 const SmallVectorImpl<ISD::InputArg> &Ins,
                 DebugLoc dl, SelectionDAG &DAG,
-                SmallVectorImpl<SDValue> &InVals);
+                SmallVectorImpl<SDValue> &InVals) const;
 
     virtual SDValue
       LowerReturn(SDValue Chain,
                   CallingConv::ID CallConv, bool isVarArg,
                   const SmallVectorImpl<ISD::OutputArg> &Outs,
-                  DebugLoc dl, SelectionDAG &DAG);
+                  DebugLoc dl, SelectionDAG &DAG) const;
   };
 }
 
diff --git a/lib/Target/Alpha/AlphaTargetMachine.h b/lib/Target/Alpha/AlphaTargetMachine.h
index 6f3a774..0990f6d 100644
--- a/lib/Target/Alpha/AlphaTargetMachine.h
+++ b/lib/Target/Alpha/AlphaTargetMachine.h
@@ -44,8 +44,8 @@ public:
   virtual const AlphaRegisterInfo *getRegisterInfo() const {
     return &InstrInfo.getRegisterInfo();
   }
-  virtual AlphaTargetLowering* getTargetLowering() const {
-    return const_cast<AlphaTargetLowering*>(&TLInfo);
+  virtual const AlphaTargetLowering* getTargetLowering() const {
+    return &TLInfo;
   }
   virtual const TargetData       *getTargetData() const { return &DataLayout; }
   virtual AlphaJITInfo* getJITInfo() {