#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/CommandLine.h"
+#include "llvm/ADT/SmallSet.h"
using namespace llvm;
}
}
+/// findDeadCallerSavedReg - Return a caller-saved register that isn't live
+/// when it reaches the "return" instruction. We can then pop a stack object
+/// to this register without worry about clobbering it.
+static unsigned findDeadCallerSavedReg(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator &MBBI,
+ const TargetRegisterInfo &TRI,
+ bool Is64Bit) {
+ const MachineFunction *MF = MBB.getParent();
+ const Function *F = MF->getFunction();
+ if (!F || MF->getMMI().callsEHReturn())
+ return 0;
+
+ static const unsigned CallerSavedRegs32Bit[] = {
+ X86::EAX, X86::EDX, X86::ECX
+ };
+
+ static const unsigned CallerSavedRegs64Bit[] = {
+ X86::RAX, X86::RDX, X86::RCX, X86::RSI, X86::RDI,
+ X86::R8, X86::R9, X86::R10, X86::R11
+ };
+
+ unsigned Opc = MBBI->getOpcode();
+ switch (Opc) {
+ default: return 0;
+ case X86::RET:
+ case X86::RETI:
+ case X86::TCRETURNdi:
+ case X86::TCRETURNri:
+ case X86::TCRETURNmi:
+ case X86::TCRETURNdi64:
+ case X86::TCRETURNri64:
+ case X86::TCRETURNmi64:
+ case X86::EH_RETURN:
+ case X86::EH_RETURN64: {
+ SmallSet<unsigned, 8> Uses;
+ for (unsigned i = 0, e = MBBI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = MBBI->getOperand(i);
+ if (!MO.isReg() || MO.isDef())
+ continue;
+ unsigned Reg = MO.getReg();
+ if (!Reg)
+ continue;
+ for (const unsigned *AsI = TRI.getOverlaps(Reg); *AsI; ++AsI)
+ Uses.insert(*AsI);
+ }
+
+ const unsigned *CS = Is64Bit ? CallerSavedRegs64Bit : CallerSavedRegs32Bit;
+ for (; *CS; ++CS)
+ if (!Uses.count(*CS))
+ return *CS;
+ }
+ }
+
+ return 0;
+}
+
+
/// emitSPUpdate - Emit a series of instructions to increment / decrement the
/// stack pointer by a constant value.
static
void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
- unsigned StackPtr, int64_t NumBytes, bool Is64Bit,
- const TargetInstrInfo &TII) {
+ unsigned StackPtr, int64_t NumBytes,
+ bool Is64Bit, const TargetInstrInfo &TII,
+ const TargetRegisterInfo &TRI) {
bool isSub = NumBytes < 0;
uint64_t Offset = isSub ? -NumBytes : NumBytes;
unsigned Opc = isSub ?
while (Offset) {
uint64_t ThisVal = (Offset > Chunk) ? Chunk : Offset;
+ if (ThisVal == (Is64Bit ? 8 : 4)) {
+ // Use push / pop instead.
+ unsigned Reg = isSub
+ ? (unsigned)(Is64Bit ? X86::RAX : X86::EAX)
+ : findDeadCallerSavedReg(MBB, MBBI, TRI, Is64Bit);
+ if (Reg) {
+ Opc = isSub
+ ? (Is64Bit ? X86::PUSH64r : X86::PUSH32r)
+ : (Is64Bit ? X86::POP64r : X86::POP32r);
+ BuildMI(MBB, MBBI, DL, TII.get(Opc))
+ .addReg(Reg, getDefRegState(!isSub) | getUndefRegState(isSub));
+ Offset -= ThisVal;
+ continue;
+ }
+ }
+
MachineInstr *MI =
BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr)
- .addReg(StackPtr)
- .addImm(ThisVal);
+ .addReg(StackPtr)
+ .addImm(ThisVal);
MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
Offset -= ThisVal;
}
BuildMI(MBB, MBBI, DL, TII.get(X86::WINCALL64pcrel32))
.addExternalSymbol("__chkstk")
.addReg(StackPtr, RegState::Define | RegState::Implicit);
- emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, TII);
+ emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit,
+ TII, *RegInfo);
} else if (NumBytes)
- emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, TII);
+ emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit,
+ TII, *RegInfo);
if ((NumBytes || PushedRegs) && needsFrameMoves) {
// Mark end of stack pointer adjustment.
// We cannot use LEA here, because stack pointer was realigned. We need to
// deallocate local frame back.
if (CSSize) {
- emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, TII);
+ emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, TII, *RegInfo);
MBBI = prior(LastCSPop);
}
}
} else if (NumBytes) {
// Adjust stack pointer back: ESP += numbytes.
- emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, TII);
+ emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, TII, *RegInfo);
}
// We're returning from function via eh_return.
if (Offset) {
// Check for possible merge with preceeding ADD instruction.
Offset += mergeSPUpdates(MBB, MBBI, StackPtr, true);
- emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, TII);
+ emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, TII, *RegInfo);
}
// Jump to label or value in register.
if (RetOpcode == X86::TCRETURNdi || RetOpcode == X86::TCRETURNdi64) {
- BuildMI(MBB, MBBI, DL, TII.get((RetOpcode == X86::TCRETURNdi)
- ? X86::TAILJMPd : X86::TAILJMPd64)).
- addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
- JumpTarget.getTargetFlags());
+ MachineInstrBuilder MIB =
+ BuildMI(MBB, MBBI, DL, TII.get((RetOpcode == X86::TCRETURNdi)
+ ? X86::TAILJMPd : X86::TAILJMPd64));
+ 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) {
MachineInstrBuilder MIB =
BuildMI(MBB, MBBI, DL, TII.get((RetOpcode == X86::TCRETURNmi)
// Check for possible merge with preceeding ADD instruction.
delta += mergeSPUpdates(MBB, MBBI, StackPtr, true);
- emitSPUpdate(MBB, MBBI, StackPtr, delta, Is64Bit, TII);
+ emitSPUpdate(MBB, MBBI, StackPtr, delta, Is64Bit, TII, *RegInfo);
}
}
}
return true;
}
+
+void
+X86FrameInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
+ RegScavenger *RS) const {
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ const X86RegisterInfo *RegInfo = TM.getRegisterInfo();
+ unsigned SlotSize = RegInfo->getSlotSize();
+
+ X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
+ int32_t TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
+
+ if (TailCallReturnAddrDelta < 0) {
+ // create RETURNADDR area
+ // arg
+ // arg
+ // RETADDR
+ // { ...
+ // RETADDR area
+ // ...
+ // }
+ // [EBP]
+ MFI->CreateFixedObject(-TailCallReturnAddrDelta,
+ (-1U*SlotSize)+TailCallReturnAddrDelta, true);
+ }
+
+ if (hasFP(MF)) {
+ assert((TailCallReturnAddrDelta <= 0) &&
+ "The Delta should always be zero or negative");
+ const TargetFrameInfo &TFI = *MF.getTarget().getFrameInfo();
+
+ // Create a frame entry for the EBP register that must be saved.
+ int FrameIdx = MFI->CreateFixedObject(SlotSize,
+ -(int)SlotSize +
+ TFI.getOffsetOfLocalArea() +
+ TailCallReturnAddrDelta,
+ true);
+ assert(FrameIdx == MFI->getObjectIndexBegin() &&
+ "Slot for EBP register must be last in order to be found!");
+ FrameIdx = 0;
+ }
+}
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