Add call frame setup instruction elimination and lowerid for bunch of call-related stuff.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70728 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/MSP430/MSP430ISelLowering.cpp

@@ -426,5 +426,6 @@ const char *MSP430TargetLowering::getTargetNodeName(unsigned Opcode) const {
   default: return NULL;
   case MSP430ISD::RET_FLAG:           return "MSP430ISD::RET_FLAG";
   case MSP430ISD::RRA:                return "MSP430ISD::RRA";
+  case MSP430ISD::CALL:               return "MSP430ISD::CALL";
   }
 }

lib/Target/MSP430/MSP430InstrInfo.cpp

@@ -25,7 +25,7 @@ using namespace llvm;
 
 MSP430InstrInfo::MSP430InstrInfo(MSP430TargetMachine &tm)
   : TargetInstrInfoImpl(MSP430Insts, array_lengthof(MSP430Insts)),
-    RI(*this), TM(tm) {}
+    RI(tm, *this), TM(tm) {}
 
 bool MSP430InstrInfo::copyRegToReg(MachineBasicBlock &MBB,
                                    MachineBasicBlock::iterator I,

lib/Target/MSP430/MSP430InstrInfo.td

@@ -23,6 +23,8 @@ class SDTCisI16<int OpNum> : SDTCisVT<OpNum, i16>;
 // Type Profiles.
 //===----------------------------------------------------------------------===//
 def SDT_MSP430Call         : SDTypeProfile<0, -1, [SDTCisVT<0, iPTR>]>;
+def SDT_MSP430CallSeqStart : SDCallSeqStart<[SDTCisVT<0, i16>]>;
+def SDT_MSP430CallSeqEnd   : SDCallSeqEnd<[SDTCisVT<0, i16>, SDTCisVT<1, i16>]>;
 
 //===----------------------------------------------------------------------===//
 // MSP430 Specific Node Definitions.
@@ -34,6 +36,12 @@ def MSP430rra     : SDNode<"MSP430ISD::RRA", SDTIntUnaryOp, []>;
 
 def MSP430call    : SDNode<"MSP430ISD::CALL", SDT_MSP430Call,
                      [SDNPHasChain, SDNPOutFlag, SDNPOptInFlag]>;
+def MSP430callseq_start :
+                 SDNode<"ISD::CALLSEQ_START", SDT_MSP430CallSeqStart,
+                        [SDNPHasChain, SDNPOutFlag]>;
+def MSP430callseq_end :
+                 SDNode<"ISD::CALLSEQ_END",   SDT_MSP430CallSeqEnd,
+                        [SDNPHasChain, SDNPOptInFlag, SDNPOutFlag]>;
 
 //===----------------------------------------------------------------------===//
 // MSP430 Operand Definitions.
@@ -63,19 +71,48 @@ def zextloadi16i8 : PatFrag<(ops node:$ptr), (i16 (zextloadi8 node:$ptr))>;
 def  extloadi16i8 : PatFrag<(ops node:$ptr), (i16 ( extloadi8 node:$ptr))>;
 
 //===----------------------------------------------------------------------===//
-// Pseudo Instructions
+// Instruction list..
+
+// ADJCALLSTACKDOWN/UP implicitly use/def SP because they may be expanded into
+// a stack adjustment and the codegen must know that they may modify the stack
+// pointer before prolog-epilog rewriting occurs.
+// Pessimistically assume ADJCALLSTACKDOWN / ADJCALLSTACKUP will become
+// sub / add which can clobber SRW.
+let Defs = [SPW, SRW], Uses = [SPW] in {
+def ADJCALLSTACKDOWN : Pseudo<(outs), (ins i16imm:$amt),
+                              "#ADJCALLSTACKDOWN",
+                              [(MSP430callseq_start timm:$amt)]>;
+def ADJCALLSTACKUP   : Pseudo<(outs), (ins i16imm:$amt1, i16imm:$amt2),
+                              "#ADJCALLSTACKUP",
+                              [(MSP430callseq_end timm:$amt1, timm:$amt2)]>;
+}
+
 
 let neverHasSideEffects = 1 in
 def NOP : Pseudo<(outs), (ins), "nop", []>;
 
-//===----------------------------------------------------------------------===//
-// Real Instructions
-
 // FIXME: Provide proper encoding!
 let isReturn = 1, isTerminator = 1 in {
-  def RETI : Pseudo<(outs), (ins), "ret", [(MSP430retflag)]>;
+  def RET : Pseudo<(outs), (ins), "ret", [(MSP430retflag)]>;
 }
 
+//===----------------------------------------------------------------------===//
+//  Call Instructions...
+//
+let isCall = 1 in
+  // All calls clobber the non-callee saved registers. SPW is marked as
+  // a use to prevent stack-pointer assignments that appear immediately
+  // before calls from potentially appearing dead. Uses for argument
+  // registers are added manually.
+  let Defs = [R12W, R13W, R14W, R15W, SRW],
+      Uses = [SPW] in {
+    def CALL32r     : Pseudo<(outs), (ins GR16:$dst, variable_ops),
+                        "call\t{*}$dst", [(MSP430call GR16:$dst)]>;
+    def CALL32m     : Pseudo<(outs), (ins memsrc:$dst, variable_ops),
+                        "call\t{*}$dst", [(MSP430call (load addr:$dst))]>;
+  }
+
+
 //===----------------------------------------------------------------------===//
 // Move Instructions
 

lib/Target/MSP430/MSP430RegisterInfo.cpp

@@ -15,8 +15,10 @@
 
 #include "MSP430.h"
 #include "MSP430RegisterInfo.h"
+#include "MSP430TargetMachine.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/ADT/BitVector.h"
@@ -24,9 +26,12 @@
 using namespace llvm;
 
 // FIXME: Provide proper call frame setup / destroy opcodes.
-MSP430RegisterInfo::MSP430RegisterInfo(const TargetInstrInfo &tii)
-  : MSP430GenRegisterInfo(MSP430::NOP, MSP430::NOP),
-    TII(tii) {}
+MSP430RegisterInfo::MSP430RegisterInfo(MSP430TargetMachine &tm,
+                                       const TargetInstrInfo &tii)
+  : MSP430GenRegisterInfo(MSP430::ADJCALLSTACKDOWN, MSP430::ADJCALLSTACKUP),
+    TM(tm), TII(tii) {
+  StackAlign = TM.getFrameInfo()->getStackAlignment();
+}
 
 const unsigned*
 MSP430RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
@@ -73,6 +78,68 @@ bool MSP430RegisterInfo::hasFP(const MachineFunction &MF) const {
   return NoFramePointerElim || MF.getFrameInfo()->hasVarSizedObjects();
 }
 
+bool MSP430RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
+  return !MF.getFrameInfo()->hasVarSizedObjects();
+}
+
+void MSP430RegisterInfo::
+eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
+                              MachineBasicBlock::iterator I) const {
+  if (!hasReservedCallFrame(MF)) {
+    // If the stack pointer can be changed after prologue, turn the
+    // adjcallstackup instruction into a 'sub SPW, <amt>' and the
+    // adjcallstackdown instruction into 'add SPW, <amt>'
+    // TODO: consider using push / pop instead of sub + store / add
+    MachineInstr *Old = I;
+    uint64_t Amount = Old->getOperand(0).getImm();
+    if (Amount != 0) {
+      // We need to keep the stack aligned properly.  To do this, we round the
+      // amount of space needed for the outgoing arguments up to the next
+      // alignment boundary.
+      Amount = (Amount+StackAlign-1)/StackAlign*StackAlign;
+
+      MachineInstr *New = 0;
+      if (Old->getOpcode() == getCallFrameSetupOpcode()) {
+        New = BuildMI(MF, Old->getDebugLoc(),
+                      TII.get(MSP430::SUB16ri), MSP430::SPW)
+          .addReg(MSP430::SPW).addImm(Amount);
+      } else {
+        assert(Old->getOpcode() == getCallFrameDestroyOpcode());
+        // factor out the amount the callee already popped.
+        uint64_t CalleeAmt = Old->getOperand(1).getImm();
+        Amount -= CalleeAmt;
+        if (Amount)
+          New = BuildMI(MF, Old->getDebugLoc(),
+                        TII.get(MSP430::ADD16ri), MSP430::SPW)
+            .addReg(MSP430::SPW).addImm(Amount);
+      }
+
+      if (New) {
+        // The SRW implicit def is dead.
+        New->getOperand(3).setIsDead();
+
+        // Replace the pseudo instruction with a new instruction...
+        MBB.insert(I, New);
+      }
+    }
+  } else if (I->getOpcode() == getCallFrameDestroyOpcode()) {
+    // If we are performing frame pointer elimination and if the callee pops
+    // something off the stack pointer, add it back.
+    if (uint64_t CalleeAmt = I->getOperand(1).getImm()) {
+      MachineInstr *Old = I;
+      MachineInstr *New =
+        BuildMI(MF, Old->getDebugLoc(), TII.get(MSP430::SUB16ri),
+                MSP430::SPW).addReg(MSP430::SPW).addImm(CalleeAmt);
+      // The SRW implicit def is dead.
+      New->getOperand(3).setIsDead();
+
+      MBB.insert(I, New);
+    }
+  }
+
+  MBB.erase(I);
+}
+
 void
 MSP430RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
                                         int SPAdj, RegScavenger *RS) const {

lib/Target/MSP430/MSP430RegisterInfo.h

@@ -20,12 +20,18 @@
 namespace llvm {
 
 class TargetInstrInfo;
+class MSP430TargetMachine;
 
 struct MSP430RegisterInfo : public MSP430GenRegisterInfo {
 private:
+  MSP430TargetMachine &TM;
   const TargetInstrInfo &TII;
+
+  /// StackAlign - Default stack alignment.
+  ///
+  unsigned StackAlign;
 public:
-  MSP430RegisterInfo(const TargetInstrInfo &tii);
+  MSP430RegisterInfo(MSP430TargetMachine &tm, const TargetInstrInfo &tii);
 
   /// Code Generation virtual methods...
   const unsigned *getCalleeSavedRegs(const MachineFunction *MF = 0) const;
@@ -36,6 +42,11 @@ public:
   BitVector getReservedRegs(const MachineFunction &MF) const;
 
   bool hasFP(const MachineFunction &MF) const;
+  bool hasReservedCallFrame(MachineFunction &MF) const;
+
+  void eliminateCallFramePseudoInstr(MachineFunction &MF,
+                                     MachineBasicBlock &MBB,
+                                     MachineBasicBlock::iterator I) const;
 
   void eliminateFrameIndex(MachineBasicBlock::iterator II,
                            int SPAdj, RegScavenger *RS = NULL) const;