From cbb70ce070d220642b038ea101d9c0f9fbf860d6 Mon Sep 17 00:00:00 2001
From: dim <dim@FreeBSD.org>
Date: Sun, 20 Feb 2011 12:57:14 +0000
Subject: Vendor import of llvm trunk r126079:
http://llvm.org/svn/llvm-project/llvm/trunk@126079
---
lib/Target/X86/X86FrameLowering.cpp | 994 ++++++++++++++++++++++++++++++++++++
1 file changed, 994 insertions(+)
create mode 100644 lib/Target/X86/X86FrameLowering.cpp
(limited to 'lib/Target/X86/X86FrameLowering.cpp')
diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp
new file mode 100644
index 0000000..0a3f931
--- /dev/null
+++ b/lib/Target/X86/X86FrameLowering.cpp
@@ -0,0 +1,994 @@
+//=======- X86FrameLowering.cpp - X86 Frame Information ------------*- C++ -*-====//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the X86 implementation of TargetFrameLowering class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "X86FrameLowering.h"
+#include "X86InstrBuilder.h"
+#include "X86InstrInfo.h"
+#include "X86MachineFunctionInfo.h"
+#include "X86TargetMachine.h"
+#include "llvm/Function.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/ADT/SmallSet.h"
+
+using namespace llvm;
+
+// FIXME: completely move here.
+extern cl::opt<bool> ForceStackAlign;
+
+bool X86FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
+ return !MF.getFrameInfo()->hasVarSizedObjects();
+}
+
+/// hasFP - Return true if the specified function should have a dedicated frame
+/// pointer register. This is true if the function has variable sized allocas
+/// or if frame pointer elimination is disabled.
+bool X86FrameLowering::hasFP(const MachineFunction &MF) const {
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+ const MachineModuleInfo &MMI = MF.getMMI();
+ const TargetRegisterInfo *RI = TM.getRegisterInfo();
+
+ return (DisableFramePointerElim(MF) ||
+ RI->needsStackRealignment(MF) ||
+ MFI->hasVarSizedObjects() ||
+ MFI->isFrameAddressTaken() ||
+ MF.getInfo<X86MachineFunctionInfo>()->getForceFramePointer() ||
+ MMI.callsUnwindInit());
+}
+
+static unsigned getSUBriOpcode(unsigned is64Bit, int64_t Imm) {
+ if (is64Bit) {
+ if (isInt<8>(Imm))
+ return X86::SUB64ri8;
+ return X86::SUB64ri32;
+ } else {
+ if (isInt<8>(Imm))
+ return X86::SUB32ri8;
+ return X86::SUB32ri;
+ }
+}
+
+static unsigned getADDriOpcode(unsigned is64Bit, int64_t Imm) {
+ if (is64Bit) {
+ if (isInt<8>(Imm))
+ return X86::ADD64ri8;
+ return X86::ADD64ri32;
+ } else {
+ if (isInt<8>(Imm))
+ return X86::ADD32ri8;
+ return X86::ADD32ri;
+ }
+}
+
+/// 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,
+ const TargetRegisterInfo &TRI) {
+ bool isSub = NumBytes < 0;
+ uint64_t Offset = isSub ? -NumBytes : NumBytes;
+ unsigned Opc = isSub ?
+ getSUBriOpcode(Is64Bit, Offset) :
+ getADDriOpcode(Is64Bit, Offset);
+ uint64_t Chunk = (1LL << 31) - 1;
+ DebugLoc DL = MBB.findDebugLoc(MBBI);
+
+ 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);
+ MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
+ Offset -= ThisVal;
+ }
+}
+
+/// mergeSPUpdatesUp - Merge two stack-manipulating instructions upper iterator.
+static
+void mergeSPUpdatesUp(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
+ unsigned StackPtr, uint64_t *NumBytes = NULL) {
+ if (MBBI == MBB.begin()) return;
+
+ MachineBasicBlock::iterator PI = prior(MBBI);
+ unsigned Opc = PI->getOpcode();
+ if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
+ Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
+ PI->getOperand(0).getReg() == StackPtr) {
+ if (NumBytes)
+ *NumBytes += PI->getOperand(2).getImm();
+ MBB.erase(PI);
+ } else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
+ Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
+ PI->getOperand(0).getReg() == StackPtr) {
+ if (NumBytes)
+ *NumBytes -= PI->getOperand(2).getImm();
+ MBB.erase(PI);
+ }
+}
+
+/// mergeSPUpdatesDown - Merge two stack-manipulating instructions lower iterator.
+static
+void mergeSPUpdatesDown(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator &MBBI,
+ unsigned StackPtr, uint64_t *NumBytes = NULL) {
+ // FIXME: THIS ISN'T RUN!!!
+ return;
+
+ if (MBBI == MBB.end()) return;
+
+ MachineBasicBlock::iterator NI = llvm::next(MBBI);
+ if (NI == MBB.end()) return;
+
+ unsigned Opc = NI->getOpcode();
+ if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
+ Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
+ NI->getOperand(0).getReg() == StackPtr) {
+ if (NumBytes)
+ *NumBytes -= NI->getOperand(2).getImm();
+ MBB.erase(NI);
+ MBBI = NI;
+ } else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
+ Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
+ NI->getOperand(0).getReg() == StackPtr) {
+ if (NumBytes)
+ *NumBytes += NI->getOperand(2).getImm();
+ MBB.erase(NI);
+ MBBI = NI;
+ }
+}
+
+/// mergeSPUpdates - Checks the instruction before/after the passed
+/// instruction. If it is an ADD/SUB instruction it is deleted argument and the
+/// stack adjustment is returned as a positive value for ADD 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;
+
+ MachineBasicBlock::iterator PI = doMergeWithPrevious ? prior(MBBI) : MBBI;
+ MachineBasicBlock::iterator NI = doMergeWithPrevious ? 0 : llvm::next(MBBI);
+ unsigned Opc = PI->getOpcode();
+ int Offset = 0;
+
+ if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
+ Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
+ PI->getOperand(0).getReg() == StackPtr){
+ Offset += PI->getOperand(2).getImm();
+ MBB.erase(PI);
+ if (!doMergeWithPrevious) MBBI = NI;
+ } else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
+ Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
+ PI->getOperand(0).getReg() == StackPtr) {
+ Offset -= PI->getOperand(2).getImm();
+ MBB.erase(PI);
+ if (!doMergeWithPrevious) MBBI = NI;
+ }
+
+ return Offset;
+}
+
+static bool isEAXLiveIn(MachineFunction &MF) {
+ for (MachineRegisterInfo::livein_iterator II = MF.getRegInfo().livein_begin(),
+ EE = MF.getRegInfo().livein_end(); II != EE; ++II) {
+ unsigned Reg = II->first;
+
+ if (Reg == X86::EAX || Reg == X86::AX ||
+ Reg == X86::AH || Reg == X86::AL)
+ return true;
+ }
+
+ return false;
+}
+
+void X86FrameLowering::emitCalleeSavedFrameMoves(MachineFunction &MF,
+ MCSymbol *Label,
+ unsigned FramePtr) const {
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ MachineModuleInfo &MMI = MF.getMMI();
+
+ // Add callee saved registers to move list.
+ const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
+ if (CSI.empty()) return;
+
+ std::vector<MachineMove> &Moves = MMI.getFrameMoves();
+ const TargetData *TD = TM.getTargetData();
+ bool HasFP = hasFP(MF);
+
+ // Calculate amount of bytes used for return address storing.
+ int stackGrowth = -TD->getPointerSize();
+
+ // FIXME: This is dirty hack. The code itself is pretty mess right now.
+ // It should be rewritten from scratch and generalized sometimes.
+
+ // Determine maximum offset (minumum due to stack growth).
+ int64_t MaxOffset = 0;
+ for (std::vector<CalleeSavedInfo>::const_iterator
+ I = CSI.begin(), E = CSI.end(); I != E; ++I)
+ MaxOffset = std::min(MaxOffset,
+ MFI->getObjectOffset(I->getFrameIdx()));
+
+ // Calculate offsets.
+ int64_t saveAreaOffset = (HasFP ? 3 : 2) * stackGrowth;
+ for (std::vector<CalleeSavedInfo>::const_iterator
+ I = CSI.begin(), E = CSI.end(); I != E; ++I) {
+ int64_t Offset = MFI->getObjectOffset(I->getFrameIdx());
+ unsigned Reg = I->getReg();
+ Offset = MaxOffset - Offset + saveAreaOffset;
+
+ // Don't output a new machine move if we're re-saving the frame
+ // pointer. This happens when the PrologEpilogInserter has inserted an extra
+ // "PUSH" of the frame pointer -- the "emitPrologue" method automatically
+ // generates one when frame pointers are used. If we generate a "machine
+ // move" for this extra "PUSH", the linker will lose track of the fact that
+ // the frame pointer should have the value of the first "PUSH" when it's
+ // trying to unwind.
+ //
+ // FIXME: This looks inelegant. It's possibly correct, but it's covering up
+ // another bug. I.e., one where we generate a prolog like this:
+ //
+ // pushl %ebp
+ // movl %esp, %ebp
+ // pushl %ebp
+ // pushl %esi
+ // ...
+ //
+ // The immediate re-push of EBP is unnecessary. At the least, it's an
+ // optimization bug. EBP can be used as a scratch register in certain
+ // cases, but probably not when we have a frame pointer.
+ if (HasFP && FramePtr == Reg)
+ continue;
+
+ MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
+ MachineLocation CSSrc(Reg);
+ Moves.push_back(MachineMove(Label, CSDst, CSSrc));
+ }
+}
+
+/// emitPrologue - Push callee-saved registers onto the stack, which
+/// automatically adjust the stack pointer. Adjust the stack pointer to allocate
+/// space for local variables. Also emit labels used by the exception handler to
+/// generate the exception handling frames.
+void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
+ MachineBasicBlock &MBB = MF.front(); // Prologue goes in entry BB.
+ MachineBasicBlock::iterator MBBI = MBB.begin();
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ const Function *Fn = MF.getFunction();
+ const X86RegisterInfo *RegInfo = TM.getRegisterInfo();
+ const X86InstrInfo &TII = *TM.getInstrInfo();
+ MachineModuleInfo &MMI = MF.getMMI();
+ X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
+ bool needsFrameMoves = MMI.hasDebugInfo() ||
+ !Fn->doesNotThrow() || UnwindTablesMandatory;
+ uint64_t MaxAlign = MFI->getMaxAlignment(); // Desired stack alignment.
+ uint64_t StackSize = MFI->getStackSize(); // Number of bytes to allocate.
+ bool HasFP = hasFP(MF);
+ bool Is64Bit = STI.is64Bit();
+ bool IsWin64 = STI.isTargetWin64();
+ unsigned StackAlign = getStackAlignment();
+ unsigned SlotSize = RegInfo->getSlotSize();
+ unsigned FramePtr = RegInfo->getFrameRegister(MF);
+ unsigned StackPtr = RegInfo->getStackRegister();
+
+ DebugLoc DL;
+
+ // If we're forcing a stack realignment we can't rely on just the frame
+ // info, we need to know the ABI stack alignment as well in case we
+ // have a call out. Otherwise just make sure we have some alignment - we'll
+ // go with the minimum SlotSize.
+ if (ForceStackAlign) {
+ if (MFI->hasCalls())
+ MaxAlign = (StackAlign > MaxAlign) ? StackAlign : MaxAlign;
+ else if (MaxAlign < SlotSize)
+ MaxAlign = SlotSize;
+ }
+
+ // Add RETADDR move area to callee saved frame size.
+ int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
+ if (TailCallReturnAddrDelta < 0)
+ X86FI->setCalleeSavedFrameSize(
+ X86FI->getCalleeSavedFrameSize() - TailCallReturnAddrDelta);
+
+ // If this is x86-64 and the Red Zone is not disabled, if we are a leaf
+ // function, and use up to 128 bytes of stack space, don't have a frame
+ // pointer, calls, or dynamic alloca then we do not need to adjust the
+ // stack pointer (we fit in the Red Zone).
+ if (Is64Bit && !Fn->hasFnAttr(Attribute::NoRedZone) &&
+ !RegInfo->needsStackRealignment(MF) &&
+ !MFI->hasVarSizedObjects() && // No dynamic alloca.
+ !MFI->adjustsStack() && // No calls.
+ !IsWin64) { // Win64 has no Red Zone
+ uint64_t MinSize = X86FI->getCalleeSavedFrameSize();
+ if (HasFP) MinSize += SlotSize;
+ StackSize = std::max(MinSize, StackSize > 128 ? StackSize - 128 : 0);
+ MFI->setStackSize(StackSize);
+ }
+
+ // Insert stack pointer adjustment for later moving of return addr. Only
+ // applies to tail call optimized functions where the callee argument stack
+ // size is bigger than the callers.
+ if (TailCallReturnAddrDelta < 0) {
+ MachineInstr *MI =
+ BuildMI(MBB, MBBI, DL,
+ TII.get(getSUBriOpcode(Is64Bit, -TailCallReturnAddrDelta)),
+ StackPtr)
+ .addReg(StackPtr)
+ .addImm(-TailCallReturnAddrDelta);
+ MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
+ }
+
+ // Mapping for machine moves:
+ //
+ // DST: VirtualFP AND
+ // SRC: VirtualFP => DW_CFA_def_cfa_offset
+ // ELSE => DW_CFA_def_cfa
+ //
+ // SRC: VirtualFP AND
+ // DST: Register => DW_CFA_def_cfa_register
+ //
+ // ELSE
+ // OFFSET < 0 => DW_CFA_offset_extended_sf
+ // REG < 64 => DW_CFA_offset + Reg
+ // ELSE => DW_CFA_offset_extended
+
+ std::vector<MachineMove> &Moves = MMI.getFrameMoves();
+ const TargetData *TD = MF.getTarget().getTargetData();
+ uint64_t NumBytes = 0;
+ int stackGrowth = -TD->getPointerSize();
+
+ if (HasFP) {
+ // Calculate required stack adjustment.
+ uint64_t FrameSize = StackSize - SlotSize;
+ if (RegInfo->needsStackRealignment(MF))
+ FrameSize = (FrameSize + MaxAlign - 1) / MaxAlign * MaxAlign;
+
+ NumBytes = FrameSize - X86FI->getCalleeSavedFrameSize();
+
+ // Get the offset of the stack slot for the EBP register, which is
+ // guaranteed to be the last slot by processFunctionBeforeFrameFinalized.
+ // Update the frame offset adjustment.
+ MFI->setOffsetAdjustment(-NumBytes);
+
+ // Save EBP/RBP into the appropriate stack slot.
+ BuildMI(MBB, MBBI, DL, TII.get(Is64Bit ? X86::PUSH64r : X86::PUSH32r))
+ .addReg(FramePtr, RegState::Kill);
+
+ if (needsFrameMoves) {
+ // Mark the place where EBP/RBP was saved.
+ MCSymbol *FrameLabel = MMI.getContext().CreateTempSymbol();
+ BuildMI(MBB, MBBI, DL, TII.get(X86::PROLOG_LABEL)).addSym(FrameLabel);
+
+ // Define the current CFA rule to use the provided offset.
+ if (StackSize) {
+ MachineLocation SPDst(MachineLocation::VirtualFP);
+ MachineLocation SPSrc(MachineLocation::VirtualFP, 2 * stackGrowth);
+ Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc));
+ } else {
+ MachineLocation SPDst(StackPtr);
+ MachineLocation SPSrc(StackPtr, stackGrowth);
+ Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc));
+ }
+
+ // Change the rule for the FramePtr to be an "offset" rule.
+ MachineLocation FPDst(MachineLocation::VirtualFP, 2 * stackGrowth);
+ MachineLocation FPSrc(FramePtr);
+ Moves.push_back(MachineMove(FrameLabel, FPDst, FPSrc));
+ }
+
+ // Update EBP with the new base value...
+ BuildMI(MBB, MBBI, DL,
+ TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr), FramePtr)
+ .addReg(StackPtr);
+
+ if (needsFrameMoves) {
+ // Mark effective beginning of when frame pointer becomes valid.
+ MCSymbol *FrameLabel = MMI.getContext().CreateTempSymbol();
+ BuildMI(MBB, MBBI, DL, TII.get(X86::PROLOG_LABEL)).addSym(FrameLabel);
+
+ // Define the current CFA to use the EBP/RBP register.
+ MachineLocation FPDst(FramePtr);
+ MachineLocation FPSrc(MachineLocation::VirtualFP);
+ Moves.push_back(MachineMove(FrameLabel, FPDst, FPSrc));
+ }
+
+ // Mark the FramePtr as live-in in every block except the entry.
+ for (MachineFunction::iterator I = llvm::next(MF.begin()), E = MF.end();
+ I != E; ++I)
+ I->addLiveIn(FramePtr);
+
+ // Realign stack
+ if (RegInfo->needsStackRealignment(MF)) {
+ MachineInstr *MI =
+ BuildMI(MBB, MBBI, DL,
+ TII.get(Is64Bit ? X86::AND64ri32 : X86::AND32ri),
+ StackPtr).addReg(StackPtr).addImm(-MaxAlign);
+
+ // The EFLAGS implicit def is dead.
+ MI->getOperand(3).setIsDead();
+ }
+ } else {
+ NumBytes = StackSize - X86FI->getCalleeSavedFrameSize();
+ }
+
+ // Skip the callee-saved push instructions.
+ bool PushedRegs = false;
+ int StackOffset = 2 * stackGrowth;
+
+ while (MBBI != MBB.end() &&
+ (MBBI->getOpcode() == X86::PUSH32r ||
+ MBBI->getOpcode() == X86::PUSH64r)) {
+ PushedRegs = true;
+ ++MBBI;
+
+ if (!HasFP && needsFrameMoves) {
+ // Mark callee-saved push instruction.
+ MCSymbol *Label = MMI.getContext().CreateTempSymbol();
+ BuildMI(MBB, MBBI, DL, TII.get(X86::PROLOG_LABEL)).addSym(Label);
+
+ // Define the current CFA rule to use the provided offset.
+ unsigned Ptr = StackSize ?
+ MachineLocation::VirtualFP : StackPtr;
+ MachineLocation SPDst(Ptr);
+ MachineLocation SPSrc(Ptr, StackOffset);
+ Moves.push_back(MachineMove(Label, SPDst, SPSrc));
+ StackOffset += stackGrowth;
+ }
+ }
+
+ DL = MBB.findDebugLoc(MBBI);
+
+ // If there is an SUB32ri of ESP immediately before this instruction, merge
+ // the two. This can be the case when tail call elimination is enabled and
+ // the callee has more arguments then the caller.
+ NumBytes -= mergeSPUpdates(MBB, MBBI, StackPtr, true);
+
+ // If there is an ADD32ri or SUB32ri of ESP immediately after this
+ // instruction, merge the two instructions.
+ mergeSPUpdatesDown(MBB, MBBI, StackPtr, &NumBytes);
+
+ // Adjust stack pointer: ESP -= numbytes.
+
+ // Windows and cygwin/mingw require a prologue helper routine when allocating
+ // more than 4K bytes on the stack. Windows uses __chkstk and cygwin/mingw
+ // uses __alloca. __alloca and the 32-bit version of __chkstk will probe the
+ // stack and adjust the stack pointer in one go. The 64-bit version of
+ // __chkstk is only responsible for probing the stack. The 64-bit prologue is
+ // responsible for adjusting the stack pointer. Touching the stack at 4K
+ // increments is necessary to ensure that the guard pages used by the OS
+ // virtual memory manager are allocated in correct sequence.
+ if (NumBytes >= 4096 &&
+ (STI.isTargetCygMing() || STI.isTargetWin32()) &&
+ !STI.isTargetEnvMacho()) {
+ // Check whether EAX is livein for this function.
+ bool isEAXAlive = isEAXLiveIn(MF);
+
+ const char *StackProbeSymbol =
+ STI.isTargetWindows() ? "_chkstk" : "_alloca";
+ if (Is64Bit && STI.isTargetCygMing())
+ StackProbeSymbol = "__chkstk";
+ unsigned CallOp = Is64Bit ? X86::CALL64pcrel32 : X86::CALLpcrel32;
+ if (!isEAXAlive) {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
+ .addImm(NumBytes);
+ BuildMI(MBB, MBBI, DL, TII.get(CallOp))
+ .addExternalSymbol(StackProbeSymbol)
+ .addReg(StackPtr, RegState::Define | RegState::Implicit)
+ .addReg(X86::EFLAGS, RegState::Define | RegState::Implicit);
+ } else {
+ // Save EAX
+ BuildMI(MBB, MBBI, DL, TII.get(X86::PUSH32r))
+ .addReg(X86::EAX, RegState::Kill);
+
+ // Allocate NumBytes-4 bytes on stack. We'll also use 4 already
+ // allocated bytes for EAX.
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
+ .addImm(NumBytes - 4);
+ BuildMI(MBB, MBBI, DL, TII.get(CallOp))
+ .addExternalSymbol(StackProbeSymbol)
+ .addReg(StackPtr, RegState::Define | RegState::Implicit)
+ .addReg(X86::EFLAGS, RegState::Define | RegState::Implicit);
+
+ // Restore EAX
+ MachineInstr *MI = addRegOffset(BuildMI(MF, DL, TII.get(X86::MOV32rm),
+ X86::EAX),
+ StackPtr, false, NumBytes - 4);
+ MBB.insert(MBBI, MI);
+ }
+ } else if (NumBytes >= 4096 &&
+ STI.isTargetWin64() &&
+ !STI.isTargetEnvMacho()) {
+ // Sanity check that EAX is not livein for this function. It should
+ // not be, so throw an assert.
+ assert(!isEAXLiveIn(MF) && "EAX is livein in the Win64 case!");
+
+ // Handle the 64-bit Windows ABI case where we need to call __chkstk.
+ // Function prologue is responsible for adjusting the stack pointer.
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
+ .addImm(NumBytes);
+ 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, *RegInfo);
+ } else if (NumBytes)
+ emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit,
+ TII, *RegInfo);
+
+ if ((NumBytes || PushedRegs) && needsFrameMoves) {
+ // Mark end of stack pointer adjustment.
+ MCSymbol *Label = MMI.getContext().CreateTempSymbol();
+ BuildMI(MBB, MBBI, DL, TII.get(X86::PROLOG_LABEL)).addSym(Label);
+
+ if (!HasFP && NumBytes) {
+ // Define the current CFA rule to use the provided offset.
+ if (StackSize) {
+ MachineLocation SPDst(MachineLocation::VirtualFP);
+ MachineLocation SPSrc(MachineLocation::VirtualFP,
+ -StackSize + stackGrowth);
+ Moves.push_back(MachineMove(Label, SPDst, SPSrc));
+ } else {
+ MachineLocation SPDst(StackPtr);
+ MachineLocation SPSrc(StackPtr, stackGrowth);
+ Moves.push_back(MachineMove(Label, SPDst, SPSrc));
+ }
+ }
+
+ // Emit DWARF info specifying the offsets of the callee-saved registers.
+ if (PushedRegs)
+ emitCalleeSavedFrameMoves(MF, Label, HasFP ? FramePtr : StackPtr);
+ }
+}
+
+void X86FrameLowering::emitEpilogue(MachineFunction &MF,
+ MachineBasicBlock &MBB) const {
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+ X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
+ const X86RegisterInfo *RegInfo = TM.getRegisterInfo();
+ const X86InstrInfo &TII = *TM.getInstrInfo();
+ MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
+ assert(MBBI != MBB.end() && "Returning block has no instructions");
+ unsigned RetOpcode = MBBI->getOpcode();
+ DebugLoc DL = MBBI->getDebugLoc();
+ bool Is64Bit = STI.is64Bit();
+ unsigned StackAlign = getStackAlignment();
+ unsigned SlotSize = RegInfo->getSlotSize();
+ unsigned FramePtr = RegInfo->getFrameRegister(MF);
+ unsigned StackPtr = RegInfo->getStackRegister();
+
+ switch (RetOpcode) {
+ default:
+ llvm_unreachable("Can only insert epilog into returning blocks");
+ 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:
+ break; // These are ok
+ }
+
+ // Get the number of bytes to allocate from the FrameInfo.
+ uint64_t StackSize = MFI->getStackSize();
+ uint64_t MaxAlign = MFI->getMaxAlignment();
+ unsigned CSSize = X86FI->getCalleeSavedFrameSize();
+ uint64_t NumBytes = 0;
+
+ // If we're forcing a stack realignment we can't rely on just the frame
+ // info, we need to know the ABI stack alignment as well in case we
+ // have a call out. Otherwise just make sure we have some alignment - we'll
+ // go with the minimum.
+ if (ForceStackAlign) {
+ if (MFI->hasCalls())
+ MaxAlign = (StackAlign > MaxAlign) ? StackAlign : MaxAlign;
+ else
+ MaxAlign = MaxAlign ? MaxAlign : 4;
+ }
+
+ if (hasFP(MF)) {
+ // Calculate required stack adjustment.
+ uint64_t FrameSize = StackSize - SlotSize;
+ if (RegInfo->needsStackRealignment(MF))
+ FrameSize = (FrameSize + MaxAlign - 1)/MaxAlign*MaxAlign;
+
+ NumBytes = FrameSize - CSSize;
+
+ // Pop EBP.
+ BuildMI(MBB, MBBI, DL,
+ TII.get(Is64Bit ? X86::POP64r : X86::POP32r), FramePtr);
+ } else {
+ NumBytes = StackSize - CSSize;
+ }
+
+ // Skip the callee-saved pop instructions.
+ MachineBasicBlock::iterator LastCSPop = MBBI;
+ while (MBBI != MBB.begin()) {
+ MachineBasicBlock::iterator PI = prior(MBBI);
+ unsigned Opc = PI->getOpcode();
+
+ if (Opc != X86::POP32r && Opc != X86::POP64r && Opc != X86::DBG_VALUE &&
+ !PI->getDesc().isTerminator())
+ break;
+
+ --MBBI;
+ }
+
+ DL = MBBI->getDebugLoc();
+
+ // If there is an ADD32ri or SUB32ri of ESP immediately before this
+ // instruction, merge the two instructions.
+ if (NumBytes || MFI->hasVarSizedObjects())
+ mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);
+
+ // If dynamic alloca is used, then reset esp to point to the last callee-saved
+ // slot before popping them off! Same applies for the case, when stack was
+ // realigned.
+ if (RegInfo->needsStackRealignment(MF)) {
+ // 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, *RegInfo);
+ MBBI = prior(LastCSPop);
+ }
+
+ BuildMI(MBB, MBBI, DL,
+ TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr),
+ StackPtr).addReg(FramePtr);
+ } else if (MFI->hasVarSizedObjects()) {
+ if (CSSize) {
+ unsigned Opc = Is64Bit ? X86::LEA64r : X86::LEA32r;
+ MachineInstr *MI =
+ addRegOffset(BuildMI(MF, DL, TII.get(Opc), StackPtr),
+ FramePtr, false, -CSSize);
+ MBB.insert(MBBI, MI);
+ } else {
+ BuildMI(MBB, MBBI, DL,
+ TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr), StackPtr)
+ .addReg(FramePtr);
+ }
+ } else if (NumBytes) {
+ // Adjust stack pointer back: ESP += numbytes.
+ emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, TII, *RegInfo);
+ }
+
+ // 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(Is64Bit ? 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 preceeding ADD instruction.
+ Offset += mergeSPUpdates(MBB, MBBI, StackPtr, true);
+ emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, TII, *RegInfo);
+ }
+
+ // Jump to label or value in register.
+ if (RetOpcode == X86::TCRETURNdi || RetOpcode == X86::TCRETURNdi64) {
+ 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)
+ ? X86::TAILJMPm : X86::TAILJMPm64));
+ for (unsigned i = 0; i != 5; ++i)
+ MIB.addOperand(MBBI->getOperand(i));
+ } else if (RetOpcode == X86::TCRETURNri64) {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr64)).
+ addReg(JumpTarget.getReg(), RegState::Kill);
+ } else {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr)).
+ addReg(JumpTarget.getReg(), RegState::Kill);
+ }
+
+ MachineInstr *NewMI = prior(MBBI);
+ for (unsigned i = 2, e = MBBI->getNumOperands(); i != e; ++i)
+ NewMI->addOperand(MBBI->getOperand(i));
+
+ // Delete the pseudo instruction TCRETURN.
+ MBB.erase(MBBI);
+ } else if ((RetOpcode == X86::RET || RetOpcode == X86::RETI) &&
+ (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 preceeding ADD instruction.
+ delta += mergeSPUpdates(MBB, MBBI, StackPtr, true);
+ emitSPUpdate(MBB, MBBI, StackPtr, delta, Is64Bit, TII, *RegInfo);
+ }
+}
+
+void
+X86FrameLowering::getInitialFrameState(std::vector<MachineMove> &Moves) const {
+ // Calculate amount of bytes used for return address storing
+ int stackGrowth = (STI.is64Bit() ? -8 : -4);
+ const X86RegisterInfo *RI = TM.getRegisterInfo();
+
+ // Initial state of the frame pointer is esp+stackGrowth.
+ MachineLocation Dst(MachineLocation::VirtualFP);
+ MachineLocation Src(RI->getStackRegister(), stackGrowth);
+ Moves.push_back(MachineMove(0, Dst, Src));
+
+ // Add return address to move list
+ MachineLocation CSDst(RI->getStackRegister(), stackGrowth);
+ MachineLocation CSSrc(RI->getRARegister());
+ Moves.push_back(MachineMove(0, CSDst, CSSrc));
+}
+
+int X86FrameLowering::getFrameIndexOffset(const MachineFunction &MF, int FI) const {
+ const X86RegisterInfo *RI =
+ static_cast<const X86RegisterInfo*>(MF.getTarget().getRegisterInfo());
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+ int Offset = MFI->getObjectOffset(FI) - getOffsetOfLocalArea();
+ uint64_t StackSize = MFI->getStackSize();
+
+ if (RI->needsStackRealignment(MF)) {
+ if (FI < 0) {
+ // Skip the saved EBP.
+ Offset += RI->getSlotSize();
+ } else {
+ unsigned Align = MFI->getObjectAlignment(FI);
+ assert((-(Offset + StackSize)) % Align == 0);
+ Align = 0;
+ return Offset + StackSize;
+ }
+ // FIXME: Support tail calls
+ } else {
+ if (!hasFP(MF))
+ return Offset + StackSize;
+
+ // Skip the saved EBP.
+ Offset += RI->getSlotSize();
+
+ // Skip the RETADDR move area
+ const X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
+ int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
+ if (TailCallReturnAddrDelta < 0)
+ Offset -= TailCallReturnAddrDelta;
+ }
+
+ return Offset;
+}
+
+bool X86FrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MI,
+ const std::vector<CalleeSavedInfo> &CSI,
+ const TargetRegisterInfo *TRI) const {
+ if (CSI.empty())
+ return false;
+
+ DebugLoc DL = MBB.findDebugLoc(MI);
+
+ MachineFunction &MF = *MBB.getParent();
+
+ bool isWin64 = STI.isTargetWin64();
+ unsigned SlotSize = STI.is64Bit() ? 8 : 4;
+ unsigned FPReg = TRI->getFrameRegister(MF);
+ unsigned CalleeFrameSize = 0;
+
+ const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
+ X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
+
+ unsigned Opc = STI.is64Bit() ? X86::PUSH64r : X86::PUSH32r;
+ for (unsigned i = CSI.size(); i != 0; --i) {
+ unsigned Reg = CSI[i-1].getReg();
+ // Add the callee-saved register as live-in. It's killed at the spill.
+ MBB.addLiveIn(Reg);
+ if (Reg == FPReg)
+ // X86RegisterInfo::emitPrologue will handle spilling of frame register.
+ continue;
+ if (!X86::VR128RegClass.contains(Reg) && !isWin64) {
+ CalleeFrameSize += SlotSize;
+ BuildMI(MBB, MI, DL, TII.get(Opc)).addReg(Reg, RegState::Kill);
+ } else {
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.storeRegToStackSlot(MBB, MI, Reg, true, CSI[i-1].getFrameIdx(),
+ RC, TRI);
+ }
+ }
+
+ X86FI->setCalleeSavedFrameSize(CalleeFrameSize);
+ return true;
+}
+
+bool X86FrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MI,
+ const std::vector<CalleeSavedInfo> &CSI,
+ const TargetRegisterInfo *TRI) const {
+ if (CSI.empty())
+ return false;
+
+ DebugLoc DL = MBB.findDebugLoc(MI);
+
+ MachineFunction &MF = *MBB.getParent();
+ const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
+ unsigned FPReg = TRI->getFrameRegister(MF);
+ bool isWin64 = STI.isTargetWin64();
+ unsigned Opc = STI.is64Bit() ? X86::POP64r : X86::POP32r;
+ for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
+ unsigned Reg = CSI[i].getReg();
+ if (Reg == FPReg)
+ // X86RegisterInfo::emitEpilogue will handle restoring of frame register.
+ continue;
+ if (!X86::VR128RegClass.contains(Reg) && !isWin64) {
+ BuildMI(MBB, MI, DL, TII.get(Opc), Reg);
+ } else {
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.loadRegFromStackSlot(MBB, MI, Reg, CSI[i].getFrameIdx(),
+ RC, TRI);
+ }
+ }
+ return true;
+}
+
+void
+X86FrameLowering::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 TargetFrameLowering &TFI = *MF.getTarget().getFrameLowering();
+
+ // 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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