dynamic stack allocas

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20273 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Alpha/AlphaISelPattern.cpp

@@ -26,6 +26,7 @@
 #include "llvm/Target/TargetLowering.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Support/Debug.h"
 #include <set>
 #include <algorithm>
 using namespace llvm;
@@ -180,7 +181,6 @@ AlphaTargetLowering::LowerArguments(Function &F, SelectionDAG &DAG)
             DAG.getNode(ISD::TRUNCATE, getValueType(I->getType()), newroot);
         break;
       }
-      ++count;
     } else { //more args
       // Create the frame index object for this incoming parameter...
       int FI = MFI->CreateFixedObject(8, 8 * (count - 6));
@@ -191,19 +191,14 @@ AlphaTargetLowering::LowerArguments(Function &F, SelectionDAG &DAG)
       argt = newroot = DAG.getLoad(getValueType(I->getType()), 
                                    DAG.getEntryNode(), FIN);
     }
+    ++count;
     DAG.setRoot(newroot.getValue(1));
     ArgValues.push_back(argt);
   }
 
   BuildMI(&BB, Alpha::IDEF, 0, Alpha::R29);
   BuildMI(&BB, Alpha::BIS, 2, GP).addReg(Alpha::R29).addReg(Alpha::R29);
-  for (int i = 0; i < count; ++i) {
+  for (int i = 0; i < count && i < 6; ++i) {
-    if (argPreg[i] == Alpha::F16 || argPreg[i] == Alpha::F17 || 
-        argPreg[i] == Alpha::F18 || argPreg[i] == Alpha::F19 || 
-        argPreg[i] == Alpha::F20 || argPreg[i] == Alpha::F21)
-    {
-      assert(argOpc[i] == Alpha::CPYS && "Using BIS for a float??");
-    }
     BuildMI(&BB, argOpc[i], 2, 
             argVreg[i]).addReg(argPreg[i]).addReg(argPreg[i]);
   }
@@ -311,6 +306,7 @@ public:
   /// InstructionSelectBasicBlock - This callback is invoked by
   /// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
   virtual void InstructionSelectBasicBlock(SelectionDAG &DAG) {
+    DEBUG(BB->dump());
     // Codegen the basic block.
     Select(DAG.getRoot());
     
@@ -570,8 +566,9 @@ unsigned ISel::SelectExprFP(SDOperand N, unsigned Result)
         BuildMI(BB, Opc, 1, Result).addConstantPoolIndex(CP->getIndex());
       }
       else if(Address.getOpcode() == ISD::FrameIndex) {
-        Tmp1 = cast<FrameIndexSDNode>(Address)->getIndex();
+        BuildMI(BB, Opc, 2, Result)
-        BuildMI(BB, Opc, 2, Result).addFrameIndex(Tmp1).addReg(Alpha::F31);
+          .addFrameIndex(cast<FrameIndexSDNode>(Address)->getIndex())
+          .addReg(Alpha::F31);
       } else {
         long offset;
         SelectAddr(Address, Tmp1, offset);
@@ -636,7 +633,9 @@ unsigned ISel::SelectExprFP(SDOperand N, unsigned Result)
       }
       else if(Address.getOpcode() == ISD::FrameIndex) {
         Tmp2 = cast<FrameIndexSDNode>(Address)->getIndex();
-        BuildMI(BB, Alpha::LDS, 2, Tmp1).addFrameIndex(Tmp2).addReg(Alpha::F31);
+        BuildMI(BB, Alpha::LDS, 2, Tmp1)
+          .addFrameIndex(cast<FrameIndexSDNode>(Address)->getIndex())
+          .addReg(Alpha::F31);
       } else {
         long offset;
         SelectAddr(Address, Tmp2, offset);
@@ -723,6 +722,47 @@ unsigned ISel::SelectExpr(SDOperand N) {
     Node->dump();
     assert(0 && "Node not handled!\n");
  
+  case ISD::DYNAMIC_STACKALLOC:
+    // Generate both result values.
+    if (Result != 1)
+      ExprMap[N.getValue(1)] = 1;   // Generate the token
+    else
+      Result = ExprMap[N.getValue(0)] = MakeReg(N.getValue(0).getValueType());
+
+    // FIXME: We are currently ignoring the requested alignment for handling
+    // greater than the stack alignment.  This will need to be revisited at some
+    // point.  Align = N.getOperand(2);
+
+    if (!isa<ConstantSDNode>(N.getOperand(2)) ||
+        cast<ConstantSDNode>(N.getOperand(2))->getValue() != 0) {
+      std::cerr << "Cannot allocate stack object with greater alignment than"
+                << " the stack alignment yet!";
+      abort();
+    }
+  
+    Select(N.getOperand(0));
+    if (ConstantSDNode* CN = dyn_cast<ConstantSDNode>(N.getOperand(1)))
+    {
+      if (CN->getValue() < 32000)
+      {
+        BuildMI(BB, Alpha::LDA, 2, Alpha::R30)
+          .addImm(-CN->getValue()).addReg(Alpha::R30);
+      } else {
+        Tmp1 = SelectExpr(N.getOperand(1));
+        // Subtract size from stack pointer, thereby allocating some space.
+        BuildMI(BB, Alpha::SUBQ, 2, Alpha::R30).addReg(Alpha::R30).addReg(Tmp1);
+      }
+    } else {
+      Tmp1 = SelectExpr(N.getOperand(1));
+      // Subtract size from stack pointer, thereby allocating some space.
+      BuildMI(BB, Alpha::SUBQ, 2, Alpha::R30).addReg(Alpha::R30).addReg(Tmp1);
+    }
+
+    // Put a pointer to the space into the result register, by copying the stack
+    // pointer.
+    BuildMI(BB, Alpha::BIS, 1, Result).addReg(Alpha::R30).addReg(Alpha::R30);
+    return Result;
+
   case ISD::ConstantPool:
     Tmp1 = cast<ConstantPoolSDNode>(N)->getIndex();
     AlphaLowering.restoreGP(BB);
@@ -730,8 +770,9 @@ unsigned ISel::SelectExpr(SDOperand N) {
     return Result;
 
   case ISD::FrameIndex:
-    Tmp1 = cast<FrameIndexSDNode>(N)->getIndex();
+    BuildMI(BB, Alpha::LDA, 2, Result)
-    BuildMI(BB, Alpha::LDA, 2, Result).addFrameIndex(Tmp1).addReg(Alpha::F31);
+      .addFrameIndex(cast<FrameIndexSDNode>(N)->getIndex())
+      .addReg(Alpha::F31);
     return Result;
   
   case ISD::EXTLOAD:
@@ -776,8 +817,9 @@ unsigned ISel::SelectExpr(SDOperand N) {
         BuildMI(BB, Opc, 1, Result).addConstantPoolIndex(CP->getIndex());
       }
       else if(Address.getOpcode() == ISD::FrameIndex) {
-        Tmp1 = cast<FrameIndexSDNode>(Address)->getIndex();
+        BuildMI(BB, Opc, 2, Result)
-        BuildMI(BB, Opc, 2, Result).addFrameIndex(Tmp1).addReg(Alpha::F31);
+          .addFrameIndex(cast<FrameIndexSDNode>(Address)->getIndex())
+          .addReg(Alpha::F31);
       } else {
         long offset;
         SelectAddr(Address, Tmp1, offset);
@@ -1111,14 +1153,16 @@ unsigned ISel::SelectExpr(SDOperand N) {
           //Can only compare doubles, and dag won't promote for me
           if (SetCC->getOperand(0).getValueType() == MVT::f32)
           {
-            std::cerr << "Setcc On float?\n";
+            //assert(0 && "Setcc On float?\n");
+            std::cerr << "Setcc on float!\n";
             Tmp3 = MakeReg(MVT::f64);
             BuildMI(BB, Alpha::CVTST, 1, Tmp3).addReg(Tmp1);
             Tmp1 = Tmp3;
           }
           if (SetCC->getOperand(1).getValueType() == MVT::f32)
           {
-            std::cerr << "Setcc On float?\n";
+            //assert (0 && "Setcc On float?\n");
+            std::cerr << "Setcc on float!\n";
             Tmp3 = MakeReg(MVT::f64);
             BuildMI(BB, Alpha::CVTST, 1, Tmp3).addReg(Tmp2);
             Tmp2 = Tmp3;
@@ -1338,7 +1382,6 @@ void ISel::Select(SDOperand N) {
 
   SDNode *Node = N.Val;
   
-
   switch (opcode) {
 
   default:
@@ -1457,8 +1500,9 @@ void ISel::Select(SDOperand N) {
       }
       else if(Address.getOpcode() == ISD::FrameIndex)
       {
-        Tmp2 = cast<FrameIndexSDNode>(Address)->getIndex();
+        BuildMI(BB, Opc, 3).addReg(Tmp1)
-        BuildMI(BB, Opc, 3).addReg(Tmp1).addFrameIndex(Tmp2).addReg(Alpha::F31);
+          .addFrameIndex(cast<FrameIndexSDNode>(Address)->getIndex())
+          .addReg(Alpha::F31);
       }
       else
       {
@@ -1475,7 +1519,7 @@ void ISel::Select(SDOperand N) {
   case ISD::LOAD:
   case ISD::CopyFromReg:
   case ISD::CALL:
-    //   case ISD::DYNAMIC_STACKALLOC:
+  case ISD::DYNAMIC_STACKALLOC:
     ExprMap.erase(N);
     SelectExpr(N);
     return;

lib/Target/Alpha/AlphaRegisterInfo.cpp

@@ -30,6 +30,21 @@
 #include <iostream>
 using namespace llvm;
 
+static long getLower16(long l)
+{
+  long y = l / 65536;
+  if (l % 65536 > 32767)
+    ++y;
+  return l - y * 65536;
+}
+
+static long getUpper16(long l)
+{
+  long y = l / 65536;
+  if (l % 65536 > 32767)
+    ++y;
+  return y;
+}
 
 AlphaRegisterInfo::AlphaRegisterInfo()
   : AlphaGenRegisterInfo(Alpha::ADJUSTSTACKDOWN, Alpha::ADJUSTSTACKUP)
@@ -102,7 +117,6 @@ void AlphaRegisterInfo::
 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
                               MachineBasicBlock::iterator I) const {
   if (hasFP(MF)) {
-    assert(0 && "TODO");
     // If we have a frame pointer, turn the adjcallstackup instruction into a
     // 'sub ESP, <amt>' and the adjcallstackdown instruction into 'add ESP,
     // <amt>'
@@ -115,31 +129,39 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
       unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
       Amount = (Amount+Align-1)/Align*Align;
 
-//    MachineInstr *New;
+      MachineInstr *New;
-//       if (Old->getOpcode() == X86::ADJCALLSTACKDOWN) {
+      if (Old->getOpcode() == Alpha::ADJUSTSTACKDOWN) {
-// 	New=BuildMI(X86::SUB32ri, 1, X86::ESP, MachineOperand::UseAndDef)
+ 	New=BuildMI(Alpha::LDA, 2, Alpha::R30)
-//               .addZImm(Amount);
+          .addImm(-Amount).addReg(Alpha::R30);
-//       } else {
+      } else {
-// 	assert(Old->getOpcode() == X86::ADJCALLSTACKUP);
+ 	assert(Old->getOpcode() == Alpha::ADJUSTSTACKUP);
-// 	New=BuildMI(X86::ADD32ri, 1, X86::ESP, MachineOperand::UseAndDef)
+ 	New=BuildMI(Alpha::LDA, 2, Alpha::R30)
-//               .addZImm(Amount);
+          .addImm(Amount).addReg(Alpha::R30);
-//       }
+      }
       
       // Replace the pseudo instruction with a new instruction...
-      //MBB.insert(I, New);
+      MBB.insert(I, New);
-      abort();
     }
   }
 
   MBB.erase(I);
 }
 
+//Alpha has a slightly funny stack:
+//Args 
+//<- incoming SP
+//fixed locals (and spills, callee saved, etc)
+//<- FP
+//variable locals
+//<- SP
+
 void
 AlphaRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II) const {
   unsigned i = 0;
   MachineInstr &MI = *II;
   MachineBasicBlock &MBB = *MI.getParent();
   MachineFunction &MF = *MBB.getParent();
+  bool FP = hasFP(MF);
 
   while (!MI.getOperand(i).isFrameIndex()) {
     ++i;
@@ -149,19 +171,29 @@ AlphaRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II) const {
   int FrameIndex = MI.getOperand(i).getFrameIndex();
 
   // Add the base register of R30 (SP) or R15 (FP).
-  MI.SetMachineOperandReg(i + 1, hasFP(MF) ? Alpha::R15 : Alpha::R30);
+  MI.SetMachineOperandReg(i + 1, FP ? Alpha::R15 : Alpha::R30);
   
-  // Now add the frame object offset to the offset from r1.
+  // Now add the frame object offset to the offset from the virtual frame index.
   int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
 
-  // If we're not using a Frame Pointer that has been set to the value of the
+  DEBUG(std::cerr << "FI: " << FrameIndex << " Offset: " << Offset << "\n");
-  // SP before having the stack size subtracted from it, then add the stack size
+
-  // to Offset to get the correct offset.
   Offset += MF.getFrameInfo()->getStackSize();
   
+  DEBUG(std::cerr << "Corrected Offset " << Offset << 
+        " for stack size: " << MF.getFrameInfo()->getStackSize() << "\n");
+
   if (Offset > 32767 || Offset < -32768) {
-     std::cerr << "Offset needs to be " << Offset << "\n";
+    //so in this case, we need to use a temporary register, and move the original
-     assert(0 && "stack too big");
+    //inst off the SP/FP
+    //fix up the old:
+    MI.SetMachineOperandReg(i + 1, Alpha::R28);
+    MI.SetMachineOperandConst(i, MachineOperand::MO_SignExtendedImmed, 
+                              getLower16(Offset));
+    //insert the new
+    MachineInstr* nMI=BuildMI(Alpha::LDAH, 2, Alpha::R28)
+      .addImm(getUpper16(Offset)).addReg(FP ? Alpha::R15 : Alpha::R30);
+    MBB.insert(--II, nMI);
   } else {
     MI.SetMachineOperandConst(i, MachineOperand::MO_SignExtendedImmed, Offset);
   }
@@ -173,6 +205,7 @@ void AlphaRegisterInfo::emitPrologue(MachineFunction &MF) const {
   MachineBasicBlock::iterator MBBI = MBB.begin();
   MachineFrameInfo *MFI = MF.getFrameInfo();
   MachineInstr *MI;
+  bool FP = hasFP(MF);
   
   //handle GOP offset
   MI = BuildMI(Alpha::LDGP, 0);
@@ -181,42 +214,48 @@ void AlphaRegisterInfo::emitPrologue(MachineFunction &MF) const {
   // Get the number of bytes to allocate from the FrameInfo
   unsigned NumBytes = MFI->getStackSize();
 
-  if (MFI->hasCalls()) {
+  if (MFI->hasCalls() && !FP) {
     // We reserve argument space for call sites in the function immediately on 
     // entry to the current function.  This eliminates the need for add/sub 
     // brackets around call sites.
+    //If there is a frame pointer, then we don't do this
     NumBytes += MFI->getMaxCallFrameSize();
     std::cerr << "Added " << MFI->getMaxCallFrameSize() << " to the stack due to calls\n";
   }
 
+  if (FP)
+    NumBytes += 8; //reserve space for the old FP
+
   // Do we need to allocate space on the stack?
   if (NumBytes == 0) return;
 
-  // Add the size of R30 to  NumBytes size for the store of R30 to the 
-  // stack
-//   std::cerr << "Spillsize of R30 is " << getSpillSize(Alpha::R30) << "\n";
-//   NumBytes = NumBytes + getSpillSize(Alpha::R30)/8;
-
   // Update frame info to pretend that this is part of the stack...
   MFI->setStackSize(NumBytes);
 
   // adjust stack pointer: r30 -= numbytes
-  
   if (NumBytes <= 32767) {
     MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(-NumBytes).addReg(Alpha::R30);
     MBB.insert(MBBI, MI);
   } else if ((unsigned long)NumBytes <= (unsigned long)32767 * (unsigned long)65536) {
-    long y = NumBytes / 65536;
+    MI=BuildMI(Alpha::LDAH, 2, Alpha::R30).addImm(getUpper16(-NumBytes)).addReg(Alpha::R30);
-    if (NumBytes % 65536 > 32767)
-      ++y;
-    MI=BuildMI(Alpha::LDAH, 2, Alpha::R30).addImm(-y).addReg(Alpha::R30);
     MBB.insert(MBBI, MI);
-    MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(-(NumBytes - y * 65536)).addReg(Alpha::R30);
+    MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(getLower16(-NumBytes)).addReg(Alpha::R30);
     MBB.insert(MBBI, MI);
   } else {
     std::cerr << "Too big a stack frame at " << NumBytes << "\n";
     abort();
   }
+
+  //now if we need to, save the old FP and set the new
+  if (FP)
+  {
+    MI=BuildMI(Alpha::STQ, 3).addReg(Alpha::R15).addImm(0).addReg(Alpha::R30);
+    MBB.insert(MBBI, MI);
+    //this must be the last instr in the prolog
+    MI=BuildMI(Alpha::BIS, 2, Alpha::R15).addReg(Alpha::R30).addReg(Alpha::R30);
+    MBB.insert(MBBI, MI);
+  }
+
 }
 
 void AlphaRegisterInfo::emitEpilogue(MachineFunction &MF,
@@ -227,21 +266,27 @@ void AlphaRegisterInfo::emitEpilogue(MachineFunction &MF,
   assert((MBBI->getOpcode() == Alpha::RET || MBBI->getOpcode() == Alpha::RETURN) &&
 	 "Can only insert epilog into returning blocks");
   
+  bool FP = hasFP(MF);
+ 
   // Get the number of bytes allocated from the FrameInfo...
   unsigned NumBytes = MFI->getStackSize();
 
+  //now if we need to, restore the old FP
+  if (FP)
+  {
+    MI=BuildMI(Alpha::LDQ, 2, Alpha::R15).addImm(0).addReg(Alpha::R15);
+    MBB.insert(MBBI, MI);
+  }
+
    if (NumBytes != 0) 
      {
        if (NumBytes <= 32767) {
          MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(NumBytes).addReg(Alpha::R30);
          MBB.insert(MBBI, MI);
        } else if ((unsigned long)NumBytes <= (unsigned long)32767 * (unsigned long)65536) {
-         long y = NumBytes / 65536;
+         MI=BuildMI(Alpha::LDAH, 2, Alpha::R30).addImm(getUpper16(NumBytes)).addReg(Alpha::R30);
-         if (NumBytes % 65536 > 32767)
-           ++y;
-         MI=BuildMI(Alpha::LDAH, 2, Alpha::R30).addImm(y).addReg(Alpha::R30);
          MBB.insert(MBBI, MI);
-         MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(NumBytes - y * 65536).addReg(Alpha::R30);
+         MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(getLower16(NumBytes)).addReg(Alpha::R30);
          MBB.insert(MBBI, MI);
        } else {
          std::cerr << "Too big a stack frame at " << NumBytes << "\n";