Revert "[X86] Fix a variable name for r237977 so that it works with every compilers."

[oota-llvm.git] / lib / Target / X86 / X86FrameLowering.cpp

diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp
index 7bbedf26080e43fb038fa96e94fe90e6cd2893b5..ef1a2d7acc946f21608367ed5db3eb1c5e88acda 100644 (file)
--- a/lib/Target/X86/X86FrameLowering.cpp
+++ b/lib/Target/X86/X86FrameLowering.cpp
@@ -205,12 +205,11 @@ static bool isEAXLiveIn(MachineFunction &MF) {
 
 /// emitSPUpdate - Emit a series of instructions to increment / decrement the
 /// stack pointer by a constant value.
 
 /// emitSPUpdate - Emit a series of instructions to increment / decrement the
 /// stack pointer by a constant value.

-void X86FrameLowering::emitSPUpdate(MachineBasicBlock &MBB,
-                                    MachineBasicBlock::iterator &MBBI,
-                                    unsigned StackPtr, int64_t NumBytes,
-                                    bool Is64BitTarget, bool Is64BitStackPtr,
-                                    bool UseLEA, const TargetInstrInfo &TII,
-                                    const TargetRegisterInfo &TRI) {
+static
+void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
+                  unsigned StackPtr, int64_t NumBytes,
+                  bool Is64BitTarget, bool Is64BitStackPtr, bool UseLEA,
+                  const TargetInstrInfo &TII, const TargetRegisterInfo &TRI) {

   bool isSub = NumBytes < 0;
   uint64_t Offset = isSub ? -NumBytes : NumBytes;
   unsigned Opc;
   bool isSub = NumBytes < 0;
   uint64_t Offset = isSub ? -NumBytes : NumBytes;
   unsigned Opc;


@@ -313,10 +312,13 @@ void mergeSPUpdatesUp(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
   }
 }
 
   }
 }
 

-int X86FrameLowering::mergeSPUpdates(MachineBasicBlock &MBB,
-                                     MachineBasicBlock::iterator &MBBI,
-                                     unsigned StackPtr,
-                                     bool doMergeWithPrevious) {
+/// mergeSPUpdates - Checks the instruction before/after the passed
+/// instruction. If it is an ADD/SUB/LEA instruction it is deleted argument and
+/// the stack adjustment is returned as a positive value for ADD/LEA and a
+/// negative for SUB.
+static int mergeSPUpdates(MachineBasicBlock &MBB,
+                          MachineBasicBlock::iterator &MBBI, unsigned StackPtr,
+                          bool doMergeWithPrevious) {

   if ((doMergeWithPrevious && MBBI == MBB.begin()) ||
       (!doMergeWithPrevious && MBBI == MBB.end()))
     return 0;
   if ((doMergeWithPrevious && MBBI == MBB.begin()) ||
       (!doMergeWithPrevious && MBBI == MBB.end()))
     return 0;


@@ -965,17 +967,6 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF,
   }
 }
 
   }
 }
 

-bool X86FrameLowering::useLEAForSPInProlog(const MachineFunction &MF) const {
-  // We can't use LEA instructions for adjusting the stack pointer if this is a
-  // leaf function in the Win64 ABI.  Only ADD instructions may be used to
-  // deallocate the stack.
-  // This means that we can use LEA for SP in two situations:
-  // 1. We *aren't* using the Win64 ABI which means we are free to use LEA.
-  // 2. We *have* a frame pointer which means we are permitted to use LEA.
-  return MF.getSubtarget<X86Subtarget>().useLeaForSP() &&
-         (!MF.getTarget().getMCAsmInfo()->usesWindowsCFI() || hasFP(MF));
-}
-

 void X86FrameLowering::emitEpilogue(MachineFunction &MF,
                                     MachineBasicBlock &MBB) const {
   const MachineFrameInfo *MFI = MF.getFrameInfo();
 void X86FrameLowering::emitEpilogue(MachineFunction &MF,
                                     MachineBasicBlock &MBB) const {
   const MachineFrameInfo *MFI = MF.getFrameInfo();


@@ -983,12 +974,14 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF,
   const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
   const X86RegisterInfo *RegInfo = STI.getRegisterInfo();
   const TargetInstrInfo &TII = *STI.getInstrInfo();
   const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
   const X86RegisterInfo *RegInfo = STI.getRegisterInfo();
   const TargetInstrInfo &TII = *STI.getInstrInfo();

-  MachineBasicBlock::iterator MBBI = MBB.getFirstTerminator();
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();

   assert(MBBI != MBB.end() && "Returning block has no instructions");
   assert(MBBI != MBB.end() && "Returning block has no instructions");

+  unsigned RetOpcode = MBBI->getOpcode();

   DebugLoc DL = MBBI->getDebugLoc();
   bool Is64Bit = STI.is64Bit();
   // standard x86_64 and NaCl use 64-bit frame/stack pointers, x32 - 32-bit.
   const bool Uses64BitFramePtr = STI.isTarget64BitLP64() || STI.isTargetNaCl64();
   DebugLoc DL = MBBI->getDebugLoc();
   bool Is64Bit = STI.is64Bit();
   // standard x86_64 and NaCl use 64-bit frame/stack pointers, x32 - 32-bit.
   const bool Uses64BitFramePtr = STI.isTarget64BitLP64() || STI.isTargetNaCl64();

+  bool HasFP = hasFP(MF);

   const bool Is64BitILP32 = STI.isTarget64BitILP32();
   unsigned SlotSize = RegInfo->getSlotSize();
   unsigned FramePtr = RegInfo->getFrameRegister(MF);
   const bool Is64BitILP32 = STI.isTarget64BitILP32();
   unsigned SlotSize = RegInfo->getSlotSize();
   unsigned FramePtr = RegInfo->getFrameRegister(MF);


@@ -999,9 +992,22 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF,
 
   bool IsWinEH = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
   bool NeedsWinEH = IsWinEH && MF.getFunction()->needsUnwindTableEntry();
 
   bool IsWinEH = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
   bool NeedsWinEH = IsWinEH && MF.getFunction()->needsUnwindTableEntry();

-  bool UseLEAForSP = useLEAForSPInProlog(MF);
+  bool UseLEAForSP = false;

 
 

-  switch (MBBI->getOpcode()) {
+  // We can't use LEA instructions for adjusting the stack pointer if this is a
+  // leaf function in the Win64 ABI.  Only ADD instructions may be used to
+  // deallocate the stack.
+  if (STI.useLeaForSP()) {
+    if (!IsWinEH) {
+      // We *aren't* using the Win64 ABI which means we are free to use LEA.
+      UseLEAForSP = true;
+    } else if (HasFP) {
+      // We *have* a frame pointer which means we are permitted to use LEA.
+      UseLEAForSP = true;
+    }
+  }
+
+  switch (RetOpcode) {

   default:
     llvm_unreachable("Can only insert epilogue into returning blocks");
   case X86::RETQ:
   default:
     llvm_unreachable("Can only insert epilogue into returning blocks");
   case X86::RETQ:


@@ -1106,15 +1112,88 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF,
   if (NeedsWinEH)
     BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_Epilogue));
 
   if (NeedsWinEH)
     BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_Epilogue));
 

-  // Add the return addr area delta back since we are not tail calling.
-  int Offset = -1 * X86FI->getTCReturnAddrDelta();
-  assert(Offset >= 0 && "TCDelta should never be positive");
-  if (Offset) {
-    MBBI = MBB.getFirstTerminator();
+  // We're returning from function via eh_return.
+  if (RetOpcode == X86::EH_RETURN || RetOpcode == X86::EH_RETURN64) {
+    MBBI = MBB.getLastNonDebugInstr();
+    MachineOperand &DestAddr  = MBBI->getOperand(0);
+    assert(DestAddr.isReg() && "Offset should be in register!");
+    BuildMI(MBB, MBBI, DL,
+            TII.get(Uses64BitFramePtr ? X86::MOV64rr : X86::MOV32rr),
+            StackPtr).addReg(DestAddr.getReg());
+  } else if (RetOpcode == X86::TCRETURNri || RetOpcode == X86::TCRETURNdi ||
+             RetOpcode == X86::TCRETURNmi ||
+             RetOpcode == X86::TCRETURNri64 || RetOpcode == X86::TCRETURNdi64 ||
+             RetOpcode == X86::TCRETURNmi64) {
+    bool isMem = RetOpcode == X86::TCRETURNmi || RetOpcode == X86::TCRETURNmi64;
+    // Tail call return: adjust the stack pointer and jump to callee.
+    MBBI = MBB.getLastNonDebugInstr();
+    MachineOperand &JumpTarget = MBBI->getOperand(0);
+    MachineOperand &StackAdjust = MBBI->getOperand(isMem ? 5 : 1);
+    assert(StackAdjust.isImm() && "Expecting immediate value.");
+
+    // Adjust stack pointer.
+    int StackAdj = StackAdjust.getImm();
+    int MaxTCDelta = X86FI->getTCReturnAddrDelta();
+    int Offset = 0;
+    assert(MaxTCDelta <= 0 && "MaxTCDelta should never be positive");
+
+    // Incoporate the retaddr area.
+    Offset = StackAdj-MaxTCDelta;
+    assert(Offset >= 0 && "Offset should never be negative");
+
+    if (Offset) {
+      // Check for possible merge with preceding ADD instruction.
+      Offset += mergeSPUpdates(MBB, MBBI, StackPtr, true);
+      emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, Uses64BitFramePtr,
+                   UseLEAForSP, TII, *RegInfo);
+    }
+
+    // Jump to label or value in register.
+    bool IsWin64 = STI.isTargetWin64();
+    if (RetOpcode == X86::TCRETURNdi || RetOpcode == X86::TCRETURNdi64) {
+      unsigned Op = (RetOpcode == X86::TCRETURNdi)
+                        ? X86::TAILJMPd
+                        : (IsWin64 ? X86::TAILJMPd64_REX : X86::TAILJMPd64);
+      MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII.get(Op));
+      if (JumpTarget.isGlobal())
+        MIB.addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
+                             JumpTarget.getTargetFlags());
+      else {
+        assert(JumpTarget.isSymbol());
+        MIB.addExternalSymbol(JumpTarget.getSymbolName(),
+                              JumpTarget.getTargetFlags());
+      }
+    } else if (RetOpcode == X86::TCRETURNmi || RetOpcode == X86::TCRETURNmi64) {
+      unsigned Op = (RetOpcode == X86::TCRETURNmi)
+                        ? X86::TAILJMPm
+                        : (IsWin64 ? X86::TAILJMPm64_REX : X86::TAILJMPm64);
+      MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII.get(Op));
+      for (unsigned i = 0; i != 5; ++i)
+        MIB.addOperand(MBBI->getOperand(i));
+    } else if (RetOpcode == X86::TCRETURNri64) {
+      BuildMI(MBB, MBBI, DL,
+              TII.get(IsWin64 ? X86::TAILJMPr64_REX : X86::TAILJMPr64))
+          .addReg(JumpTarget.getReg(), RegState::Kill);
+    } else {
+      BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr)).
+        addReg(JumpTarget.getReg(), RegState::Kill);
+    }
+
+    MachineInstr *NewMI = std::prev(MBBI);
+    NewMI->copyImplicitOps(MF, MBBI);
+
+    // Delete the pseudo instruction TCRETURN.
+    MBB.erase(MBBI);
+  } else if ((RetOpcode == X86::RETQ || RetOpcode == X86::RETL ||
+              RetOpcode == X86::RETIQ || RetOpcode == X86::RETIL) &&
+             (X86FI->getTCReturnAddrDelta() < 0)) {
+    // Add the return addr area delta back since we are not tail calling.
+    int delta = -1*X86FI->getTCReturnAddrDelta();
+    MBBI = MBB.getLastNonDebugInstr();

 
     // Check for possible merge with preceding ADD instruction.
 
     // Check for possible merge with preceding ADD instruction.

-    Offset += mergeSPUpdates(MBB, MBBI, StackPtr, true);
-    emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, Uses64BitFramePtr,
+    delta += mergeSPUpdates(MBB, MBBI, StackPtr, true);
+    emitSPUpdate(MBB, MBBI, StackPtr, delta, Is64Bit, Uses64BitFramePtr,

                  UseLEAForSP, TII, *RegInfo);
   }
 }
                  UseLEAForSP, TII, *RegInfo);
   }
 }