#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "llvm/ADT/SmallSet.h"
+#include "llvm/Analysis/EHPersonalities.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/DataLayout.h"
-#include "llvm/Function.h"
+#include "llvm/CodeGen/WinEHFuncInfo.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Function.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCSymbol.h"
-#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/Debug.h"
+#include <cstdlib>
using namespace llvm;
-// FIXME: completely move here.
-extern cl::opt<bool> ForceStackAlign;
+X86FrameLowering::X86FrameLowering(const X86Subtarget &STI,
+ unsigned StackAlignOverride)
+ : TargetFrameLowering(StackGrowsDown, StackAlignOverride,
+ STI.is64Bit() ? -8 : -4),
+ STI(STI), TII(*STI.getInstrInfo()), TRI(STI.getRegisterInfo()) {
+ // Cache a bunch of frame-related predicates for this subtarget.
+ SlotSize = TRI->getSlotSize();
+ Is64Bit = STI.is64Bit();
+ IsLP64 = STI.isTarget64BitLP64();
+ // standard x86_64 and NaCl use 64-bit frame/stack pointers, x32 - 32-bit.
+ Uses64BitFramePtr = STI.isTarget64BitLP64() || STI.isTargetNaCl64();
+ StackPtr = TRI->getStackRegister();
+}
bool X86FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
- return !MF.getFrameInfo()->hasVarSizedObjects();
+ return !MF.getFrameInfo()->hasVarSizedObjects() &&
+ !MF.getInfo<X86MachineFunctionInfo>()->getHasPushSequences();
+}
+
+/// canSimplifyCallFramePseudos - If there is a reserved call frame, the
+/// call frame pseudos can be simplified. Having a FP, as in the default
+/// implementation, is not sufficient here since we can't always use it.
+/// Use a more nuanced condition.
+bool
+X86FrameLowering::canSimplifyCallFramePseudos(const MachineFunction &MF) const {
+ return hasReservedCallFrame(MF) ||
+ (hasFP(MF) && !TRI->needsStackRealignment(MF)) ||
+ TRI->hasBasePointer(MF);
+}
+
+// needsFrameIndexResolution - Do we need to perform FI resolution for
+// this function. Normally, this is required only when the function
+// has any stack objects. However, FI resolution actually has another job,
+// not apparent from the title - it resolves callframesetup/destroy
+// that were not simplified earlier.
+// So, this is required for x86 functions that have push sequences even
+// when there are no stack objects.
+bool
+X86FrameLowering::needsFrameIndexResolution(const MachineFunction &MF) const {
+ return MF.getFrameInfo()->hasStackObjects() ||
+ MF.getInfo<X86MachineFunctionInfo>()->getHasPushSequences();
}
/// hasFP - Return true if the specified function should have a dedicated frame
bool X86FrameLowering::hasFP(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const MachineModuleInfo &MMI = MF.getMMI();
- const TargetRegisterInfo *RegInfo = TM.getRegisterInfo();
return (MF.getTarget().Options.DisableFramePointerElim(MF) ||
- RegInfo->needsStackRealignment(MF) ||
+ TRI->needsStackRealignment(MF) ||
MFI->hasVarSizedObjects() ||
- MFI->isFrameAddressTaken() ||
+ MFI->isFrameAddressTaken() || MFI->hasOpaqueSPAdjustment() ||
MF.getInfo<X86MachineFunctionInfo>()->getForceFramePointer() ||
- MMI.callsUnwindInit() || MMI.callsEHReturn());
+ MMI.callsUnwindInit() || MMI.hasEHFunclets() || MMI.callsEHReturn() ||
+ MFI->hasStackMap() || MFI->hasPatchPoint() ||
+ MFI->hasCopyImplyingStackAdjustment());
}
-static unsigned getSUBriOpcode(unsigned is64Bit, int64_t Imm) {
- if (is64Bit) {
+static unsigned getSUBriOpcode(unsigned IsLP64, int64_t Imm) {
+ if (IsLP64) {
if (isInt<8>(Imm))
return X86::SUB64ri8;
return X86::SUB64ri32;
}
}
-static unsigned getADDriOpcode(unsigned is64Bit, int64_t Imm) {
- if (is64Bit) {
+static unsigned getADDriOpcode(unsigned IsLP64, int64_t Imm) {
+ if (IsLP64) {
if (isInt<8>(Imm))
return X86::ADD64ri8;
return X86::ADD64ri32;
}
}
-static unsigned getLEArOpcode(unsigned is64Bit) {
- return is64Bit ? X86::LEA64r : X86::LEA32r;
+static unsigned getSUBrrOpcode(unsigned isLP64) {
+ return isLP64 ? X86::SUB64rr : X86::SUB32rr;
+}
+
+static unsigned getADDrrOpcode(unsigned isLP64) {
+ return isLP64 ? X86::ADD64rr : X86::ADD32rr;
+}
+
+static unsigned getANDriOpcode(bool IsLP64, int64_t Imm) {
+ if (IsLP64) {
+ if (isInt<8>(Imm))
+ return X86::AND64ri8;
+ return X86::AND64ri32;
+ }
+ if (isInt<8>(Imm))
+ return X86::AND32ri8;
+ return X86::AND32ri;
+}
+
+static unsigned getLEArOpcode(unsigned IsLP64) {
+ return IsLP64 ? X86::LEA64r : X86::LEA32r;
}
/// findDeadCallerSavedReg - Return a caller-saved register that isn't live
/// to this register without worry about clobbering it.
static unsigned findDeadCallerSavedReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
- const TargetRegisterInfo &TRI,
+ const X86RegisterInfo *TRI,
bool Is64Bit) {
const MachineFunction *MF = MBB.getParent();
const Function *F = MF->getFunction();
if (!F || MF->getMMI().callsEHReturn())
return 0;
- static const uint16_t CallerSavedRegs32Bit[] = {
- X86::EAX, X86::EDX, X86::ECX, 0
- };
-
- static const uint16_t CallerSavedRegs64Bit[] = {
- X86::RAX, X86::RDX, X86::RCX, X86::RSI, X86::RDI,
- X86::R8, X86::R9, X86::R10, X86::R11, 0
- };
+ const TargetRegisterClass &AvailableRegs = *TRI->getGPRsForTailCall(*MF);
unsigned Opc = MBBI->getOpcode();
switch (Opc) {
default: return 0;
- case X86::RET:
- case X86::RETI:
+ case X86::RETL:
+ case X86::RETQ:
+ case X86::RETIL:
+ case X86::RETIQ:
case X86::TCRETURNdi:
case X86::TCRETURNri:
case X86::TCRETURNmi:
unsigned Reg = MO.getReg();
if (!Reg)
continue;
- for (MCRegAliasIterator AI(Reg, &TRI, true); AI.isValid(); ++AI)
+ for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
Uses.insert(*AI);
}
- const uint16_t *CS = Is64Bit ? CallerSavedRegs64Bit : CallerSavedRegs32Bit;
- for (; *CS; ++CS)
- if (!Uses.count(*CS))
- return *CS;
+ for (auto CS : AvailableRegs)
+ if (!Uses.count(CS) && CS != X86::RIP)
+ return CS;
}
}
return 0;
}
+static bool isEAXLiveIn(MachineBasicBlock &MBB) {
+ for (MachineBasicBlock::RegisterMaskPair RegMask : MBB.liveins()) {
+ unsigned Reg = RegMask.PhysReg;
+
+ if (Reg == X86::RAX || Reg == X86::EAX || Reg == X86::AX ||
+ Reg == X86::AH || Reg == X86::AL)
+ return true;
+ }
+
+ return false;
+}
+
+/// Check if the flags need to be preserved before the terminators.
+/// This would be the case, if the eflags is live-in of the region
+/// composed by the terminators or live-out of that region, without
+/// being defined by a terminator.
+static bool
+flagsNeedToBePreservedBeforeTheTerminators(const MachineBasicBlock &MBB) {
+ for (const MachineInstr &MI : MBB.terminators()) {
+ bool BreakNext = false;
+ for (const MachineOperand &MO : MI.operands()) {
+ if (!MO.isReg())
+ continue;
+ unsigned Reg = MO.getReg();
+ if (Reg != X86::EFLAGS)
+ continue;
+
+ // This terminator needs an eflags that is not defined
+ // by a previous another terminator:
+ // EFLAGS is live-in of the region composed by the terminators.
+ if (!MO.isDef())
+ return true;
+ // This terminator defines the eflags, i.e., we don't need to preserve it.
+ // However, we still need to check this specific terminator does not
+ // read a live-in value.
+ BreakNext = true;
+ }
+ // We found a definition of the eflags, no need to preserve them.
+ if (BreakNext)
+ return false;
+ }
+
+ // None of the terminators use or define the eflags.
+ // Check if they are live-out, that would imply we need to preserve them.
+ for (const MachineBasicBlock *Succ : MBB.successors())
+ if (Succ->isLiveIn(X86::EFLAGS))
+ return true;
+
+ return false;
+}
/// 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, bool UseLEA,
- const TargetInstrInfo &TII, const TargetRegisterInfo &TRI) {
+void X86FrameLowering::emitSPUpdate(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator &MBBI,
+ int64_t NumBytes, bool InEpilogue) const {
bool isSub = NumBytes < 0;
uint64_t Offset = isSub ? -NumBytes : NumBytes;
- unsigned Opc;
- if (UseLEA)
- Opc = getLEArOpcode(Is64Bit);
- else
- 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 (Offset > Chunk) {
+ // Rather than emit a long series of instructions for large offsets,
+ // load the offset into a register and do one sub/add
+ unsigned Reg = 0;
+
+ if (isSub && !isEAXLiveIn(MBB))
+ Reg = (unsigned)(Is64Bit ? X86::RAX : X86::EAX);
+ else
+ Reg = findDeadCallerSavedReg(MBB, MBBI, TRI, Is64Bit);
+
+ if (Reg) {
+ unsigned Opc = Is64Bit ? X86::MOV64ri : X86::MOV32ri;
+ BuildMI(MBB, MBBI, DL, TII.get(Opc), Reg)
+ .addImm(Offset);
+ Opc = isSub
+ ? getSUBrrOpcode(Is64Bit)
+ : getADDrrOpcode(Is64Bit);
+ MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr)
+ .addReg(StackPtr)
+ .addReg(Reg);
+ MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
+ Offset = 0;
+ continue;
+ }
+ }
+
+ uint64_t ThisVal = std::min(Offset, Chunk);
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
+ unsigned Opc = isSub
? (Is64Bit ? X86::PUSH64r : X86::PUSH32r)
: (Is64Bit ? X86::POP64r : X86::POP32r);
MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(Opc))
.addReg(Reg, getDefRegState(!isSub) | getUndefRegState(isSub));
if (isSub)
MI->setFlag(MachineInstr::FrameSetup);
+ else
+ MI->setFlag(MachineInstr::FrameDestroy);
Offset -= ThisVal;
continue;
}
}
- MachineInstr *MI = NULL;
-
- if (UseLEA) {
- MI = addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr),
- StackPtr, false, isSub ? -ThisVal : ThisVal);
- } else {
- MI = BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr)
- .addReg(StackPtr)
- .addImm(ThisVal);
- MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
- }
-
+ MachineInstrBuilder MI = BuildStackAdjustment(
+ MBB, MBBI, DL, isSub ? -ThisVal : ThisVal, InEpilogue);
if (isSub)
- MI->setFlag(MachineInstr::FrameSetup);
+ MI.setMIFlag(MachineInstr::FrameSetup);
+ else
+ MI.setMIFlag(MachineInstr::FrameDestroy);
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 ||
- Opc == X86::LEA32r || Opc == X86::LEA64_32r) &&
- 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);
+MachineInstrBuilder X86FrameLowering::BuildStackAdjustment(
+ MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI, DebugLoc DL,
+ int64_t Offset, bool InEpilogue) const {
+ assert(Offset != 0 && "zero offset stack adjustment requested");
+
+ // On Atom, using LEA to adjust SP is preferred, but using it in the epilogue
+ // is tricky.
+ bool UseLEA;
+ if (!InEpilogue) {
+ // Check if inserting the prologue at the beginning
+ // of MBB would require to use LEA operations.
+ // We need to use LEA operations if EFLAGS is live in, because
+ // it means an instruction will read it before it gets defined.
+ UseLEA = STI.useLeaForSP() || MBB.isLiveIn(X86::EFLAGS);
+ } else {
+ // If we can use LEA for SP but we shouldn't, check that none
+ // of the terminators uses the eflags. Otherwise we will insert
+ // a ADD that will redefine the eflags and break the condition.
+ // Alternatively, we could move the ADD, but this may not be possible
+ // and is an optimization anyway.
+ UseLEA = canUseLEAForSPInEpilogue(*MBB.getParent());
+ if (UseLEA && !STI.useLeaForSP())
+ UseLEA = flagsNeedToBePreservedBeforeTheTerminators(MBB);
+ // If that assert breaks, that means we do not do the right thing
+ // in canUseAsEpilogue.
+ assert((UseLEA || !flagsNeedToBePreservedBeforeTheTerminators(MBB)) &&
+ "We shouldn't have allowed this insertion point");
}
-}
-
-/// 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;
+ MachineInstrBuilder MI;
+ if (UseLEA) {
+ MI = addRegOffset(BuildMI(MBB, MBBI, DL,
+ TII.get(getLEArOpcode(Uses64BitFramePtr)),
+ StackPtr),
+ StackPtr, false, Offset);
+ } else {
+ bool IsSub = Offset < 0;
+ uint64_t AbsOffset = IsSub ? -Offset : Offset;
+ unsigned Opc = IsSub ? getSUBriOpcode(Uses64BitFramePtr, AbsOffset)
+ : getADDriOpcode(Uses64BitFramePtr, AbsOffset);
+ MI = BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr)
+ .addReg(StackPtr)
+ .addImm(AbsOffset);
+ MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
}
+ return MI;
}
-/// 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) {
+int X86FrameLowering::mergeSPUpdates(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator &MBBI,
+ bool doMergeWithPrevious) const {
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);
+ MachineBasicBlock::iterator PI = doMergeWithPrevious ? std::prev(MBBI) : MBBI;
+ MachineBasicBlock::iterator NI = doMergeWithPrevious ? nullptr
+ : std::next(MBBI);
unsigned Opc = PI->getOpcode();
int Offset = 0;
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::BuildCFI(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MBBI, DebugLoc DL,
+ MCCFIInstruction CFIInst) const {
+ MachineFunction &MF = *MBB.getParent();
+ unsigned CFIIndex = MF.getMMI().addFrameInst(CFIInst);
+ BuildMI(MBB, MBBI, DL, TII.get(TargetOpcode::CFI_INSTRUCTION))
+ .addCFIIndex(CFIIndex);
}
-void X86FrameLowering::emitCalleeSavedFrameMoves(MachineFunction &MF,
- MCSymbol *Label,
- unsigned FramePtr) const {
+void
+X86FrameLowering::emitCalleeSavedFrameMoves(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MBBI,
+ DebugLoc DL) const {
+ MachineFunction &MF = *MBB.getParent();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineModuleInfo &MMI = MF.getMMI();
+ const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo();
// 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 X86RegisterInfo *RegInfo = TM.getRegisterInfo();
- bool HasFP = hasFP(MF);
-
- // Calculate amount of bytes used for return address storing.
- int stackGrowth = -RegInfo->getSlotSize();
-
- // 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 (minimum 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));
+ unsigned DwarfReg = MRI->getDwarfRegNum(Reg, true);
+ BuildCFI(MBB, MBBI, DL,
+ MCCFIInstruction::createOffset(nullptr, DwarfReg, Offset));
+ }
+}
+
+MachineInstr *X86FrameLowering::emitStackProbe(MachineFunction &MF,
+ MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MBBI,
+ DebugLoc DL,
+ bool InProlog) const {
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ if (STI.isTargetWindowsCoreCLR()) {
+ if (InProlog) {
+ return emitStackProbeInlineStub(MF, MBB, MBBI, DL, true);
+ } else {
+ return emitStackProbeInline(MF, MBB, MBBI, DL, false);
+ }
+ } else {
+ return emitStackProbeCall(MF, MBB, MBBI, DL, InProlog);
}
}
-/// getCompactUnwindRegNum - Get the compact unwind number for a given
-/// register. The number corresponds to the enum lists in
-/// compact_unwind_encoding.h.
-static int getCompactUnwindRegNum(const uint16_t *CURegs, unsigned Reg) {
- for (int Idx = 1; *CURegs; ++CURegs, ++Idx)
- if (*CURegs == Reg)
- return Idx;
+void X86FrameLowering::inlineStackProbe(MachineFunction &MF,
+ MachineBasicBlock &PrologMBB) const {
+ const StringRef ChkStkStubSymbol = "__chkstk_stub";
+ MachineInstr *ChkStkStub = nullptr;
+
+ for (MachineInstr &MI : PrologMBB) {
+ if (MI.isCall() && MI.getOperand(0).isSymbol() &&
+ ChkStkStubSymbol == MI.getOperand(0).getSymbolName()) {
+ ChkStkStub = &MI;
+ break;
+ }
+ }
- return -1;
+ if (ChkStkStub != nullptr) {
+ MachineBasicBlock::iterator MBBI = std::next(ChkStkStub->getIterator());
+ assert(std::prev(MBBI).operator==(ChkStkStub) &&
+ "MBBI expected after __chkstk_stub.");
+ DebugLoc DL = PrologMBB.findDebugLoc(MBBI);
+ emitStackProbeInline(MF, PrologMBB, MBBI, DL, true);
+ ChkStkStub->eraseFromParent();
+ }
}
-// Number of registers that can be saved in a compact unwind encoding.
-#define CU_NUM_SAVED_REGS 6
-
-/// encodeCompactUnwindRegistersWithoutFrame - Create the permutation encoding
-/// used with frameless stacks. It is passed the number of registers to be saved
-/// and an array of the registers saved.
-static uint32_t
-encodeCompactUnwindRegistersWithoutFrame(unsigned SavedRegs[CU_NUM_SAVED_REGS],
- unsigned RegCount, bool Is64Bit) {
- // The saved registers are numbered from 1 to 6. In order to encode the order
- // in which they were saved, we re-number them according to their place in the
- // register order. The re-numbering is relative to the last re-numbered
- // register. E.g., if we have registers {6, 2, 4, 5} saved in that order:
+MachineInstr *X86FrameLowering::emitStackProbeInline(
+ MachineFunction &MF, MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MBBI, DebugLoc DL, bool InProlog) const {
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ assert(STI.is64Bit() && "different expansion needed for 32 bit");
+ assert(STI.isTargetWindowsCoreCLR() && "custom expansion expects CoreCLR");
+ const TargetInstrInfo &TII = *STI.getInstrInfo();
+ const BasicBlock *LLVM_BB = MBB.getBasicBlock();
+
+ // RAX contains the number of bytes of desired stack adjustment.
+ // The handling here assumes this value has already been updated so as to
+ // maintain stack alignment.
//
- // Orig Re-Num
- // ---- ------
- // 6 6
- // 2 2
- // 4 3
- // 5 3
+ // We need to exit with RSP modified by this amount and execute suitable
+ // page touches to notify the OS that we're growing the stack responsibly.
+ // All stack probing must be done without modifying RSP.
//
- static const uint16_t CU32BitRegs[] = {
- X86::EBX, X86::ECX, X86::EDX, X86::EDI, X86::ESI, X86::EBP, 0
- };
- static const uint16_t CU64BitRegs[] = {
- X86::RBX, X86::R12, X86::R13, X86::R14, X86::R15, X86::RBP, 0
- };
- const uint16_t *CURegs = (Is64Bit ? CU64BitRegs : CU32BitRegs);
-
- for (unsigned i = 0; i != CU_NUM_SAVED_REGS; ++i) {
- int CUReg = getCompactUnwindRegNum(CURegs, SavedRegs[i]);
- if (CUReg == -1) return ~0U;
- SavedRegs[i] = CUReg;
- }
-
- // Reverse the list.
- std::swap(SavedRegs[0], SavedRegs[5]);
- std::swap(SavedRegs[1], SavedRegs[4]);
- std::swap(SavedRegs[2], SavedRegs[3]);
-
- uint32_t RenumRegs[CU_NUM_SAVED_REGS];
- for (unsigned i = CU_NUM_SAVED_REGS - RegCount; i < CU_NUM_SAVED_REGS; ++i) {
- unsigned Countless = 0;
- for (unsigned j = CU_NUM_SAVED_REGS - RegCount; j < i; ++j)
- if (SavedRegs[j] < SavedRegs[i])
- ++Countless;
-
- RenumRegs[i] = SavedRegs[i] - Countless - 1;
- }
-
- // Take the renumbered values and encode them into a 10-bit number.
- uint32_t permutationEncoding = 0;
- switch (RegCount) {
- case 6:
- permutationEncoding |= 120 * RenumRegs[0] + 24 * RenumRegs[1]
- + 6 * RenumRegs[2] + 2 * RenumRegs[3]
- + RenumRegs[4];
- break;
- case 5:
- permutationEncoding |= 120 * RenumRegs[1] + 24 * RenumRegs[2]
- + 6 * RenumRegs[3] + 2 * RenumRegs[4]
- + RenumRegs[5];
- break;
- case 4:
- permutationEncoding |= 60 * RenumRegs[2] + 12 * RenumRegs[3]
- + 3 * RenumRegs[4] + RenumRegs[5];
- break;
- case 3:
- permutationEncoding |= 20 * RenumRegs[3] + 4 * RenumRegs[4]
- + RenumRegs[5];
- break;
- case 2:
- permutationEncoding |= 5 * RenumRegs[4] + RenumRegs[5];
- break;
- case 1:
- permutationEncoding |= RenumRegs[5];
- break;
- }
-
- assert((permutationEncoding & 0x3FF) == permutationEncoding &&
- "Invalid compact register encoding!");
- return permutationEncoding;
-}
-
-/// encodeCompactUnwindRegistersWithFrame - Return the registers encoded for a
-/// compact encoding with a frame pointer.
-static uint32_t
-encodeCompactUnwindRegistersWithFrame(unsigned SavedRegs[CU_NUM_SAVED_REGS],
- bool Is64Bit) {
- static const uint16_t CU32BitRegs[] = {
- X86::EBX, X86::ECX, X86::EDX, X86::EDI, X86::ESI, X86::EBP, 0
- };
- static const uint16_t CU64BitRegs[] = {
- X86::RBX, X86::R12, X86::R13, X86::R14, X86::R15, X86::RBP, 0
- };
- const uint16_t *CURegs = (Is64Bit ? CU64BitRegs : CU32BitRegs);
-
- // Encode the registers in the order they were saved, 3-bits per register. The
- // registers are numbered from 1 to CU_NUM_SAVED_REGS.
- uint32_t RegEnc = 0;
- for (int I = CU_NUM_SAVED_REGS - 1, Idx = 0; I != -1; --I) {
- unsigned Reg = SavedRegs[I];
- if (Reg == 0) continue;
-
- int CURegNum = getCompactUnwindRegNum(CURegs, Reg);
- if (CURegNum == -1) return ~0U;
-
- // Encode the 3-bit register number in order, skipping over 3-bits for each
- // register.
- RegEnc |= (CURegNum & 0x7) << (Idx++ * 3);
- }
-
- assert((RegEnc & 0x3FFFF) == RegEnc && "Invalid compact register encoding!");
- return RegEnc;
-}
+ // MBB:
+ // SizeReg = RAX;
+ // ZeroReg = 0
+ // CopyReg = RSP
+ // Flags, TestReg = CopyReg - SizeReg
+ // FinalReg = !Flags.Ovf ? TestReg : ZeroReg
+ // LimitReg = gs magic thread env access
+ // if FinalReg >= LimitReg goto ContinueMBB
+ // RoundBB:
+ // RoundReg = page address of FinalReg
+ // LoopMBB:
+ // LoopReg = PHI(LimitReg,ProbeReg)
+ // ProbeReg = LoopReg - PageSize
+ // [ProbeReg] = 0
+ // if (ProbeReg > RoundReg) goto LoopMBB
+ // ContinueMBB:
+ // RSP = RSP - RAX
+ // [rest of original MBB]
+
+ // Set up the new basic blocks
+ MachineBasicBlock *RoundMBB = MF.CreateMachineBasicBlock(LLVM_BB);
+ MachineBasicBlock *LoopMBB = MF.CreateMachineBasicBlock(LLVM_BB);
+ MachineBasicBlock *ContinueMBB = MF.CreateMachineBasicBlock(LLVM_BB);
+
+ MachineFunction::iterator MBBIter = std::next(MBB.getIterator());
+ MF.insert(MBBIter, RoundMBB);
+ MF.insert(MBBIter, LoopMBB);
+ MF.insert(MBBIter, ContinueMBB);
+
+ // Split MBB and move the tail portion down to ContinueMBB.
+ MachineBasicBlock::iterator BeforeMBBI = std::prev(MBBI);
+ ContinueMBB->splice(ContinueMBB->begin(), &MBB, MBBI, MBB.end());
+ ContinueMBB->transferSuccessorsAndUpdatePHIs(&MBB);
+
+ // Some useful constants
+ const int64_t ThreadEnvironmentStackLimit = 0x10;
+ const int64_t PageSize = 0x1000;
+ const int64_t PageMask = ~(PageSize - 1);
+
+ // Registers we need. For the normal case we use virtual
+ // registers. For the prolog expansion we use RAX, RCX and RDX.
+ MachineRegisterInfo &MRI = MF.getRegInfo();
+ const TargetRegisterClass *RegClass = &X86::GR64RegClass;
+ const unsigned SizeReg = InProlog ? (unsigned)X86::RAX
+ : MRI.createVirtualRegister(RegClass),
+ ZeroReg = InProlog ? (unsigned)X86::RCX
+ : MRI.createVirtualRegister(RegClass),
+ CopyReg = InProlog ? (unsigned)X86::RDX
+ : MRI.createVirtualRegister(RegClass),
+ TestReg = InProlog ? (unsigned)X86::RDX
+ : MRI.createVirtualRegister(RegClass),
+ FinalReg = InProlog ? (unsigned)X86::RDX
+ : MRI.createVirtualRegister(RegClass),
+ RoundedReg = InProlog ? (unsigned)X86::RDX
+ : MRI.createVirtualRegister(RegClass),
+ LimitReg = InProlog ? (unsigned)X86::RCX
+ : MRI.createVirtualRegister(RegClass),
+ JoinReg = InProlog ? (unsigned)X86::RCX
+ : MRI.createVirtualRegister(RegClass),
+ ProbeReg = InProlog ? (unsigned)X86::RCX
+ : MRI.createVirtualRegister(RegClass);
+
+ // SP-relative offsets where we can save RCX and RDX.
+ int64_t RCXShadowSlot = 0;
+ int64_t RDXShadowSlot = 0;
+
+ // If inlining in the prolog, save RCX and RDX.
+ // Future optimization: don't save or restore if not live in.
+ if (InProlog) {
+ // Compute the offsets. We need to account for things already
+ // pushed onto the stack at this point: return address, frame
+ // pointer (if used), and callee saves.
+ X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
+ const int64_t CalleeSaveSize = X86FI->getCalleeSavedFrameSize();
+ const bool HasFP = hasFP(MF);
+ RCXShadowSlot = 8 + CalleeSaveSize + (HasFP ? 8 : 0);
+ RDXShadowSlot = RCXShadowSlot + 8;
+ // Emit the saves.
+ addRegOffset(BuildMI(&MBB, DL, TII.get(X86::MOV64mr)), X86::RSP, false,
+ RCXShadowSlot)
+ .addReg(X86::RCX);
+ addRegOffset(BuildMI(&MBB, DL, TII.get(X86::MOV64mr)), X86::RSP, false,
+ RDXShadowSlot)
+ .addReg(X86::RDX);
+ } else {
+ // Not in the prolog. Copy RAX to a virtual reg.
+ BuildMI(&MBB, DL, TII.get(X86::MOV64rr), SizeReg).addReg(X86::RAX);
+ }
-uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const {
- const X86RegisterInfo *RegInfo = TM.getRegisterInfo();
- unsigned FramePtr = RegInfo->getFrameRegister(MF);
- unsigned StackPtr = RegInfo->getStackRegister();
+ // Add code to MBB to check for overflow and set the new target stack pointer
+ // to zero if so.
+ BuildMI(&MBB, DL, TII.get(X86::XOR64rr), ZeroReg)
+ .addReg(ZeroReg, RegState::Undef)
+ .addReg(ZeroReg, RegState::Undef);
+ BuildMI(&MBB, DL, TII.get(X86::MOV64rr), CopyReg).addReg(X86::RSP);
+ BuildMI(&MBB, DL, TII.get(X86::SUB64rr), TestReg)
+ .addReg(CopyReg)
+ .addReg(SizeReg);
+ BuildMI(&MBB, DL, TII.get(X86::CMOVB64rr), FinalReg)
+ .addReg(TestReg)
+ .addReg(ZeroReg);
+
+ // FinalReg now holds final stack pointer value, or zero if
+ // allocation would overflow. Compare against the current stack
+ // limit from the thread environment block. Note this limit is the
+ // lowest touched page on the stack, not the point at which the OS
+ // will cause an overflow exception, so this is just an optimization
+ // to avoid unnecessarily touching pages that are below the current
+ // SP but already commited to the stack by the OS.
+ BuildMI(&MBB, DL, TII.get(X86::MOV64rm), LimitReg)
+ .addReg(0)
+ .addImm(1)
+ .addReg(0)
+ .addImm(ThreadEnvironmentStackLimit)
+ .addReg(X86::GS);
+ BuildMI(&MBB, DL, TII.get(X86::CMP64rr)).addReg(FinalReg).addReg(LimitReg);
+ // Jump if the desired stack pointer is at or above the stack limit.
+ BuildMI(&MBB, DL, TII.get(X86::JAE_1)).addMBB(ContinueMBB);
+
+ // Add code to roundMBB to round the final stack pointer to a page boundary.
+ BuildMI(RoundMBB, DL, TII.get(X86::AND64ri32), RoundedReg)
+ .addReg(FinalReg)
+ .addImm(PageMask);
+ BuildMI(RoundMBB, DL, TII.get(X86::JMP_1)).addMBB(LoopMBB);
+
+ // LimitReg now holds the current stack limit, RoundedReg page-rounded
+ // final RSP value. Add code to loopMBB to decrement LimitReg page-by-page
+ // and probe until we reach RoundedReg.
+ if (!InProlog) {
+ BuildMI(LoopMBB, DL, TII.get(X86::PHI), JoinReg)
+ .addReg(LimitReg)
+ .addMBB(RoundMBB)
+ .addReg(ProbeReg)
+ .addMBB(LoopMBB);
+ }
- bool Is64Bit = STI.is64Bit();
- bool HasFP = hasFP(MF);
+ addRegOffset(BuildMI(LoopMBB, DL, TII.get(X86::LEA64r), ProbeReg), JoinReg,
+ false, -PageSize);
+
+ // Probe by storing a byte onto the stack.
+ BuildMI(LoopMBB, DL, TII.get(X86::MOV8mi))
+ .addReg(ProbeReg)
+ .addImm(1)
+ .addReg(0)
+ .addImm(0)
+ .addReg(0)
+ .addImm(0);
+ BuildMI(LoopMBB, DL, TII.get(X86::CMP64rr))
+ .addReg(RoundedReg)
+ .addReg(ProbeReg);
+ BuildMI(LoopMBB, DL, TII.get(X86::JNE_1)).addMBB(LoopMBB);
+
+ MachineBasicBlock::iterator ContinueMBBI = ContinueMBB->getFirstNonPHI();
+
+ // If in prolog, restore RDX and RCX.
+ if (InProlog) {
+ addRegOffset(BuildMI(*ContinueMBB, ContinueMBBI, DL, TII.get(X86::MOV64rm),
+ X86::RCX),
+ X86::RSP, false, RCXShadowSlot);
+ addRegOffset(BuildMI(*ContinueMBB, ContinueMBBI, DL, TII.get(X86::MOV64rm),
+ X86::RDX),
+ X86::RSP, false, RDXShadowSlot);
+ }
- unsigned SavedRegs[CU_NUM_SAVED_REGS] = { 0, 0, 0, 0, 0, 0 };
- unsigned SavedRegIdx = 0;
-
- unsigned OffsetSize = (Is64Bit ? 8 : 4);
-
- unsigned PushInstr = (Is64Bit ? X86::PUSH64r : X86::PUSH32r);
- unsigned PushInstrSize = 1;
- unsigned MoveInstr = (Is64Bit ? X86::MOV64rr : X86::MOV32rr);
- unsigned MoveInstrSize = (Is64Bit ? 3 : 2);
- unsigned SubtractInstrIdx = (Is64Bit ? 3 : 2);
-
- unsigned StackDivide = (Is64Bit ? 8 : 4);
-
- unsigned InstrOffset = 0;
- unsigned StackAdjust = 0;
- unsigned StackSize = 0;
-
- MachineBasicBlock &MBB = MF.front(); // Prologue is in entry BB.
- bool ExpectEnd = false;
- for (MachineBasicBlock::iterator
- MBBI = MBB.begin(), MBBE = MBB.end(); MBBI != MBBE; ++MBBI) {
- MachineInstr &MI = *MBBI;
- unsigned Opc = MI.getOpcode();
- if (Opc == X86::PROLOG_LABEL) continue;
- if (!MI.getFlag(MachineInstr::FrameSetup)) break;
-
- // We don't exect any more prolog instructions.
- if (ExpectEnd) return 0;
-
- if (Opc == PushInstr) {
- // If there are too many saved registers, we cannot use compact encoding.
- if (SavedRegIdx >= CU_NUM_SAVED_REGS) return 0;
-
- SavedRegs[SavedRegIdx++] = MI.getOperand(0).getReg();
- StackAdjust += OffsetSize;
- InstrOffset += PushInstrSize;
- } else if (Opc == MoveInstr) {
- unsigned SrcReg = MI.getOperand(1).getReg();
- unsigned DstReg = MI.getOperand(0).getReg();
-
- if (DstReg != FramePtr || SrcReg != StackPtr)
- return 0;
-
- StackAdjust = 0;
- memset(SavedRegs, 0, sizeof(SavedRegs));
- SavedRegIdx = 0;
- InstrOffset += MoveInstrSize;
- } else if (Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
- Opc == X86::SUB32ri || Opc == X86::SUB32ri8) {
- if (StackSize)
- // We already have a stack size.
- return 0;
-
- if (!MI.getOperand(0).isReg() ||
- MI.getOperand(0).getReg() != MI.getOperand(1).getReg() ||
- MI.getOperand(0).getReg() != StackPtr || !MI.getOperand(2).isImm())
- // We need this to be a stack adjustment pointer. Something like:
- //
- // %RSP<def> = SUB64ri8 %RSP, 48
- return 0;
-
- StackSize = MI.getOperand(2).getImm() / StackDivide;
- SubtractInstrIdx += InstrOffset;
- ExpectEnd = true;
+ // Now that the probing is done, add code to continueMBB to update
+ // the stack pointer for real.
+ BuildMI(*ContinueMBB, ContinueMBBI, DL, TII.get(X86::SUB64rr), X86::RSP)
+ .addReg(X86::RSP)
+ .addReg(SizeReg);
+
+ // Add the control flow edges we need.
+ MBB.addSuccessor(ContinueMBB);
+ MBB.addSuccessor(RoundMBB);
+ RoundMBB->addSuccessor(LoopMBB);
+ LoopMBB->addSuccessor(ContinueMBB);
+ LoopMBB->addSuccessor(LoopMBB);
+
+ // Mark all the instructions added to the prolog as frame setup.
+ if (InProlog) {
+ for (++BeforeMBBI; BeforeMBBI != MBB.end(); ++BeforeMBBI) {
+ BeforeMBBI->setFlag(MachineInstr::FrameSetup);
+ }
+ for (MachineInstr &MI : *RoundMBB) {
+ MI.setFlag(MachineInstr::FrameSetup);
+ }
+ for (MachineInstr &MI : *LoopMBB) {
+ MI.setFlag(MachineInstr::FrameSetup);
+ }
+ for (MachineBasicBlock::iterator CMBBI = ContinueMBB->begin();
+ CMBBI != ContinueMBBI; ++CMBBI) {
+ CMBBI->setFlag(MachineInstr::FrameSetup);
}
}
- // Encode that we are using EBP/RBP as the frame pointer.
- uint32_t CompactUnwindEncoding = 0;
- StackAdjust /= StackDivide;
- if (HasFP) {
- if ((StackAdjust & 0xFF) != StackAdjust)
- // Offset was too big for compact encoding.
- return 0;
-
- // Get the encoding of the saved registers when we have a frame pointer.
- uint32_t RegEnc = encodeCompactUnwindRegistersWithFrame(SavedRegs, Is64Bit);
- if (RegEnc == ~0U) return 0;
+ // Possible TODO: physreg liveness for InProlog case.
- CompactUnwindEncoding |= 0x01000000;
- CompactUnwindEncoding |= (StackAdjust & 0xFF) << 16;
- CompactUnwindEncoding |= RegEnc & 0x7FFF;
- } else {
- ++StackAdjust;
- uint32_t TotalStackSize = StackAdjust + StackSize;
- if ((TotalStackSize & 0xFF) == TotalStackSize) {
- // Frameless stack with a small stack size.
- CompactUnwindEncoding |= 0x02000000;
-
- // Encode the stack size.
- CompactUnwindEncoding |= (TotalStackSize & 0xFF) << 16;
- } else {
- if ((StackAdjust & 0x7) != StackAdjust)
- // The extra stack adjustments are too big for us to handle.
- return 0;
+ return ContinueMBBI;
+}
- // Frameless stack with an offset too large for us to encode compactly.
- CompactUnwindEncoding |= 0x03000000;
+MachineInstr *X86FrameLowering::emitStackProbeCall(
+ MachineFunction &MF, MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MBBI, DebugLoc DL, bool InProlog) const {
+ bool IsLargeCodeModel = MF.getTarget().getCodeModel() == CodeModel::Large;
- // Encode the offset to the nnnnnn value in the 'subl $nnnnnn, ESP'
- // instruction.
- CompactUnwindEncoding |= (SubtractInstrIdx & 0xFF) << 16;
+ unsigned CallOp;
+ if (Is64Bit)
+ CallOp = IsLargeCodeModel ? X86::CALL64r : X86::CALL64pcrel32;
+ else
+ CallOp = X86::CALLpcrel32;
- // Encode any extra stack stack adjustments (done via push instructions).
- CompactUnwindEncoding |= (StackAdjust & 0x7) << 13;
+ const char *Symbol;
+ if (Is64Bit) {
+ if (STI.isTargetCygMing()) {
+ Symbol = "___chkstk_ms";
+ } else {
+ Symbol = "__chkstk";
}
+ } else if (STI.isTargetCygMing())
+ Symbol = "_alloca";
+ else
+ Symbol = "_chkstk";
+
+ MachineInstrBuilder CI;
+ MachineBasicBlock::iterator ExpansionMBBI = std::prev(MBBI);
+
+ // All current stack probes take AX and SP as input, clobber flags, and
+ // preserve all registers. x86_64 probes leave RSP unmodified.
+ if (Is64Bit && MF.getTarget().getCodeModel() == CodeModel::Large) {
+ // For the large code model, we have to call through a register. Use R11,
+ // as it is scratch in all supported calling conventions.
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64ri), X86::R11)
+ .addExternalSymbol(Symbol);
+ CI = BuildMI(MBB, MBBI, DL, TII.get(CallOp)).addReg(X86::R11);
+ } else {
+ CI = BuildMI(MBB, MBBI, DL, TII.get(CallOp)).addExternalSymbol(Symbol);
+ }
- // Encode the number of registers saved.
- CompactUnwindEncoding |= (SavedRegIdx & 0x7) << 10;
+ unsigned AX = Is64Bit ? X86::RAX : X86::EAX;
+ unsigned SP = Is64Bit ? X86::RSP : X86::ESP;
+ CI.addReg(AX, RegState::Implicit)
+ .addReg(SP, RegState::Implicit)
+ .addReg(AX, RegState::Define | RegState::Implicit)
+ .addReg(SP, RegState::Define | RegState::Implicit)
+ .addReg(X86::EFLAGS, RegState::Define | RegState::Implicit);
- // Get the encoding of the saved registers when we don't have a frame
- // pointer.
- uint32_t RegEnc =
- encodeCompactUnwindRegistersWithoutFrame(SavedRegs, SavedRegIdx,
- Is64Bit);
- if (RegEnc == ~0U) return 0;
+ if (Is64Bit) {
+ // MSVC x64's __chkstk and cygwin/mingw's ___chkstk_ms do not adjust %rsp
+ // themselves. It also does not clobber %rax so we can reuse it when
+ // adjusting %rsp.
+ BuildMI(MBB, MBBI, DL, TII.get(X86::SUB64rr), X86::RSP)
+ .addReg(X86::RSP)
+ .addReg(X86::RAX);
+ }
- // Encode the register encoding.
- CompactUnwindEncoding |= RegEnc & 0x3FF;
+ if (InProlog) {
+ // Apply the frame setup flag to all inserted instrs.
+ for (++ExpansionMBBI; ExpansionMBBI != MBBI; ++ExpansionMBBI)
+ ExpansionMBBI->setFlag(MachineInstr::FrameSetup);
}
- return CompactUnwindEncoding;
+ return MBBI;
}
-/// colobbersTheStack - This function checks if any of the users of EFLAGS
-/// copies the EFLAGS. We know that the code that lowers COPY of EFLAGS has
-/// to use the stack, and if we don't adjust the stack we clobber the first
-/// frame index.
-/// See X86InstrInfo::copyPhysReg.
-static bool colobbersTheStack(MachineFunction &MF) {
- MachineRegisterInfo &MRI = MF.getRegInfo();
+MachineInstr *X86FrameLowering::emitStackProbeInlineStub(
+ MachineFunction &MF, MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MBBI, DebugLoc DL, bool InProlog) const {
- for (MachineRegisterInfo::reg_iterator ri = MRI.reg_begin(X86::EFLAGS),
- re = MRI.reg_end(); ri != re; ++ri)
- if (ri->isCopy())
- return true;
+ assert(InProlog && "ChkStkStub called outside prolog!");
- return false;
+ BuildMI(MBB, MBBI, DL, TII.get(X86::CALLpcrel32))
+ .addExternalSymbol("__chkstk_stub");
+
+ return MBBI;
+}
+
+static unsigned calculateSetFPREG(uint64_t SPAdjust) {
+ // Win64 ABI has a less restrictive limitation of 240; 128 works equally well
+ // and might require smaller successive adjustments.
+ const uint64_t Win64MaxSEHOffset = 128;
+ uint64_t SEHFrameOffset = std::min(SPAdjust, Win64MaxSEHOffset);
+ // Win64 ABI requires 16-byte alignment for the UWOP_SET_FPREG opcode.
+ return SEHFrameOffset & -16;
+}
+
+// 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.
+uint64_t X86FrameLowering::calculateMaxStackAlign(const MachineFunction &MF) const {
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+ uint64_t MaxAlign = MFI->getMaxAlignment(); // Desired stack alignment.
+ unsigned StackAlign = getStackAlignment();
+ if (MF.getFunction()->hasFnAttribute("stackrealign")) {
+ if (MFI->hasCalls())
+ MaxAlign = (StackAlign > MaxAlign) ? StackAlign : MaxAlign;
+ else if (MaxAlign < SlotSize)
+ MaxAlign = SlotSize;
+ }
+ return MaxAlign;
+}
+
+void X86FrameLowering::BuildStackAlignAND(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MBBI,
+ DebugLoc DL, unsigned Reg,
+ uint64_t MaxAlign) const {
+ uint64_t Val = -MaxAlign;
+ unsigned AndOp = getANDriOpcode(Uses64BitFramePtr, Val);
+ MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(AndOp), Reg)
+ .addReg(Reg)
+ .addImm(Val)
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ // The EFLAGS implicit def is dead.
+ MI->getOperand(3).setIsDead();
}
/// 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.
+
+/*
+ Here's a gist of what gets emitted:
+
+ ; Establish frame pointer, if needed
+ [if needs FP]
+ push %rbp
+ .cfi_def_cfa_offset 16
+ .cfi_offset %rbp, -16
+ .seh_pushreg %rpb
+ mov %rsp, %rbp
+ .cfi_def_cfa_register %rbp
+
+ ; Spill general-purpose registers
+ [for all callee-saved GPRs]
+ pushq %<reg>
+ [if not needs FP]
+ .cfi_def_cfa_offset (offset from RETADDR)
+ .seh_pushreg %<reg>
+
+ ; If the required stack alignment > default stack alignment
+ ; rsp needs to be re-aligned. This creates a "re-alignment gap"
+ ; of unknown size in the stack frame.
+ [if stack needs re-alignment]
+ and $MASK, %rsp
+
+ ; Allocate space for locals
+ [if target is Windows and allocated space > 4096 bytes]
+ ; Windows needs special care for allocations larger
+ ; than one page.
+ mov $NNN, %rax
+ call ___chkstk_ms/___chkstk
+ sub %rax, %rsp
+ [else]
+ sub $NNN, %rsp
+
+ [if needs FP]
+ .seh_stackalloc (size of XMM spill slots)
+ .seh_setframe %rbp, SEHFrameOffset ; = size of all spill slots
+ [else]
+ .seh_stackalloc NNN
+
+ ; Spill XMMs
+ ; Note, that while only Windows 64 ABI specifies XMMs as callee-preserved,
+ ; they may get spilled on any platform, if the current function
+ ; calls @llvm.eh.unwind.init
+ [if needs FP]
+ [for all callee-saved XMM registers]
+ movaps %<xmm reg>, -MMM(%rbp)
+ [for all callee-saved XMM registers]
+ .seh_savexmm %<xmm reg>, (-MMM + SEHFrameOffset)
+ ; i.e. the offset relative to (%rbp - SEHFrameOffset)
+ [else]
+ [for all callee-saved XMM registers]
+ movaps %<xmm reg>, KKK(%rsp)
+ [for all callee-saved XMM registers]
+ .seh_savexmm %<xmm reg>, KKK
+
+ .seh_endprologue
+
+ [if needs base pointer]
+ mov %rsp, %rbx
+ [if needs to restore base pointer]
+ mov %rsp, -MMM(%rbp)
+
+ ; Emit CFI info
+ [if needs FP]
+ [for all callee-saved registers]
+ .cfi_offset %<reg>, (offset from %rbp)
+ [else]
+ .cfi_def_cfa_offset (offset from RETADDR)
+ [for all callee-saved registers]
+ .cfi_offset %<reg>, (offset from %rsp)
+
+ Notes:
+ - .seh directives are emitted only for Windows 64 ABI
+ - .cfi directives are emitted for all other ABIs
+ - for 32-bit code, substitute %e?? registers for %r??
+*/
+
+void X86FrameLowering::emitPrologue(MachineFunction &MF,
+ MachineBasicBlock &MBB) const {
+ assert(&STI == &MF.getSubtarget<X86Subtarget>() &&
+ "MF used frame lowering for wrong subtarget");
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->needsUnwindTableEntry();
- uint64_t MaxAlign = MFI->getMaxAlignment(); // Desired stack alignment.
+ uint64_t MaxAlign = calculateMaxStackAlign(MF); // Desired stack alignment.
uint64_t StackSize = MFI->getStackSize(); // Number of bytes to allocate.
+ bool IsFunclet = MBB.isEHFuncletEntry();
+ EHPersonality Personality = EHPersonality::Unknown;
+ if (Fn->hasPersonalityFn())
+ Personality = classifyEHPersonality(Fn->getPersonalityFn());
+ bool FnHasClrFunclet =
+ MMI.hasEHFunclets() && Personality == EHPersonality::CoreCLR;
+ bool IsClrFunclet = IsFunclet && FnHasClrFunclet;
bool HasFP = hasFP(MF);
- bool Is64Bit = STI.is64Bit();
- bool IsWin64 = STI.isTargetWin64();
- bool UseLEA = STI.useLeaForSP();
- unsigned StackAlign = getStackAlignment();
- unsigned SlotSize = RegInfo->getSlotSize();
- unsigned FramePtr = RegInfo->getFrameRegister(MF);
- unsigned StackPtr = RegInfo->getStackRegister();
- unsigned BasePtr = RegInfo->getBaseRegister();
+ bool IsWin64CC = STI.isCallingConvWin64(Fn->getCallingConv());
+ bool IsWin64Prologue = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
+ bool NeedsWinCFI = IsWin64Prologue && Fn->needsUnwindTableEntry();
+ bool NeedsDwarfCFI =
+ !IsWin64Prologue && (MMI.hasDebugInfo() || Fn->needsUnwindTableEntry());
+ unsigned FramePtr = TRI->getFrameRegister(MF);
+ const unsigned MachineFramePtr =
+ STI.isTarget64BitILP32()
+ ? getX86SubSuperRegister(FramePtr, 64) : FramePtr;
+ unsigned BasePtr = TRI->getBaseRegister();
+
+ // Debug location must be unknown since the first debug location is used
+ // to determine the end of the prologue.
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 && IsWin64Prologue)
+ report_fatal_error("Can't handle guaranteed tail call under win64 yet");
+
if (TailCallReturnAddrDelta < 0)
X86FI->setCalleeSavedFrameSize(
X86FI->getCalleeSavedFrameSize() - TailCallReturnAddrDelta);
+ bool UseStackProbe = (STI.isOSWindows() && !STI.isTargetMachO());
+
+ // The default stack probe size is 4096 if the function has no stackprobesize
+ // attribute.
+ unsigned StackProbeSize = 4096;
+ if (Fn->hasFnAttribute("stack-probe-size"))
+ Fn->getFnAttribute("stack-probe-size")
+ .getValueAsString()
+ .getAsInteger(0, StackProbeSize);
+
// 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). We also check that we don't
// push and pop from the stack.
- if (Is64Bit && !Fn->getFnAttributes().hasAttribute(Attribute::NoRedZone) &&
- !RegInfo->needsStackRealignment(MF) &&
- !MFI->hasVarSizedObjects() && // No dynamic alloca.
- !MFI->adjustsStack() && // No calls.
- !IsWin64 && // Win64 has no Red Zone
- !colobbersTheStack(MF) && // Don't push and pop.
- !MF.getTarget().Options.EnableSegmentedStacks) { // Regular stack
+ if (Is64Bit && !Fn->hasFnAttribute(Attribute::NoRedZone) &&
+ !TRI->needsStackRealignment(MF) &&
+ !MFI->hasVarSizedObjects() && // No dynamic alloca.
+ !MFI->adjustsStack() && // No calls.
+ !IsWin64CC && // Win64 has no Red Zone
+ !MFI->hasCopyImplyingStackAdjustment() && // Don't push and pop.
+ !MF.shouldSplitStack()) { // Regular stack
uint64_t MinSize = X86FI->getCalleeSavedFrameSize();
if (HasFP) MinSize += SlotSize;
StackSize = std::max(MinSize, StackSize > 128 ? StackSize - 128 : 0);
// 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)
+ BuildStackAdjustment(MBB, MBBI, DL, TailCallReturnAddrDelta,
+ /*InEpilogue=*/false)
.setMIFlag(MachineInstr::FrameSetup);
- MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
}
// Mapping for machine moves:
// REG < 64 => DW_CFA_offset + Reg
// ELSE => DW_CFA_offset_extended
- std::vector<MachineMove> &Moves = MMI.getFrameMoves();
uint64_t NumBytes = 0;
int stackGrowth = -SlotSize;
+ // Find the funclet establisher parameter
+ unsigned Establisher = X86::NoRegister;
+ if (IsClrFunclet)
+ Establisher = Uses64BitFramePtr ? X86::RCX : X86::ECX;
+ else if (IsFunclet)
+ Establisher = Uses64BitFramePtr ? X86::RDX : X86::EDX;
+
+ if (IsWin64Prologue && IsFunclet && !IsClrFunclet) {
+ // Immediately spill establisher into the home slot.
+ // The runtime cares about this.
+ // MOV64mr %rdx, 16(%rsp)
+ unsigned MOVmr = Uses64BitFramePtr ? X86::MOV64mr : X86::MOV32mr;
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(MOVmr)), StackPtr, true, 16)
+ .addReg(Establisher)
+ .setMIFlag(MachineInstr::FrameSetup);
+ MBB.addLiveIn(Establisher);
+ }
+
if (HasFP) {
// Calculate required stack adjustment.
uint64_t FrameSize = StackSize - SlotSize;
- if (RegInfo->needsStackRealignment(MF)) {
- // Callee-saved registers are pushed on stack before the stack
- // is realigned.
- FrameSize -= X86FI->getCalleeSavedFrameSize();
- NumBytes = (FrameSize + MaxAlign - 1) / MaxAlign * MaxAlign;
- } else {
- NumBytes = FrameSize - X86FI->getCalleeSavedFrameSize();
- }
+ // If required, include space for extra hidden slot for stashing base pointer.
+ if (X86FI->getRestoreBasePointer())
+ FrameSize += SlotSize;
+
+ NumBytes = FrameSize - X86FI->getCalleeSavedFrameSize();
+
+ // Callee-saved registers are pushed on stack before the stack is realigned.
+ if (TRI->needsStackRealignment(MF) && !IsWin64Prologue)
+ NumBytes = RoundUpToAlignment(NumBytes, MaxAlign);
// 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);
+ if (!IsFunclet)
+ MFI->setOffsetAdjustment(-NumBytes);
+ else
+ assert(MFI->getOffsetAdjustment() == -(int)NumBytes &&
+ "should calculate same local variable offset for funclets");
// Save EBP/RBP into the appropriate stack slot.
BuildMI(MBB, MBBI, DL, TII.get(Is64Bit ? X86::PUSH64r : X86::PUSH32r))
- .addReg(FramePtr, RegState::Kill)
+ .addReg(MachineFramePtr, RegState::Kill)
.setMIFlag(MachineInstr::FrameSetup);
- if (needsFrameMoves) {
+ if (NeedsDwarfCFI) {
// 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));
- }
+ assert(StackSize);
+ BuildCFI(MBB, MBBI, DL,
+ MCCFIInstruction::createDefCfaOffset(nullptr, 2 * stackGrowth));
// 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));
+ unsigned DwarfFramePtr = TRI->getDwarfRegNum(MachineFramePtr, true);
+ BuildCFI(MBB, MBBI, DL, MCCFIInstruction::createOffset(
+ nullptr, DwarfFramePtr, 2 * stackGrowth));
}
- // Update EBP with the new base value.
- BuildMI(MBB, MBBI, DL,
- TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr), FramePtr)
- .addReg(StackPtr)
- .setMIFlag(MachineInstr::FrameSetup);
-
- 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);
+ if (NeedsWinCFI) {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_PushReg))
+ .addImm(FramePtr)
+ .setMIFlag(MachineInstr::FrameSetup);
+ }
- // Define the current CFA to use the EBP/RBP register.
- MachineLocation FPDst(FramePtr);
- MachineLocation FPSrc(MachineLocation::VirtualFP);
- Moves.push_back(MachineMove(FrameLabel, FPDst, FPSrc));
+ if (!IsWin64Prologue && !IsFunclet) {
+ // Update EBP with the new base value.
+ BuildMI(MBB, MBBI, DL,
+ TII.get(Uses64BitFramePtr ? X86::MOV64rr : X86::MOV32rr),
+ FramePtr)
+ .addReg(StackPtr)
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ if (NeedsDwarfCFI) {
+ // Mark effective beginning of when frame pointer becomes valid.
+ // Define the current CFA to use the EBP/RBP register.
+ unsigned DwarfFramePtr = TRI->getDwarfRegNum(MachineFramePtr, true);
+ BuildCFI(MBB, MBBI, DL, MCCFIInstruction::createDefCfaRegister(
+ nullptr, DwarfFramePtr));
+ }
}
- // 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);
+ // Mark the FramePtr as live-in in every block. Don't do this again for
+ // funclet prologues.
+ if (!IsFunclet) {
+ for (MachineBasicBlock &EveryMBB : MF)
+ EveryMBB.addLiveIn(MachineFramePtr);
+ }
} else {
+ assert(!IsFunclet && "funclets without FPs not yet implemented");
NumBytes = StackSize - X86FI->getCalleeSavedFrameSize();
}
+ // For EH funclets, only allocate enough space for outgoing calls. Save the
+ // NumBytes value that we would've used for the parent frame.
+ unsigned ParentFrameNumBytes = NumBytes;
+ if (IsFunclet)
+ NumBytes = getWinEHFuncletFrameSize(MF);
+
// Skip the callee-saved push instructions.
bool PushedRegs = false;
int StackOffset = 2 * stackGrowth;
while (MBBI != MBB.end() &&
+ MBBI->getFlag(MachineInstr::FrameSetup) &&
(MBBI->getOpcode() == X86::PUSH32r ||
MBBI->getOpcode() == X86::PUSH64r)) {
PushedRegs = true;
- MBBI->setFlag(MachineInstr::FrameSetup);
+ unsigned Reg = MBBI->getOperand(0).getReg();
++MBBI;
- if (!HasFP && needsFrameMoves) {
+ if (!HasFP && NeedsDwarfCFI) {
// 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));
+ assert(StackSize);
+ BuildCFI(MBB, MBBI, DL,
+ MCCFIInstruction::createDefCfaOffset(nullptr, StackOffset));
StackOffset += stackGrowth;
}
+
+ if (NeedsWinCFI) {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_PushReg)).addImm(Reg).setMIFlag(
+ MachineInstr::FrameSetup);
+ }
}
// Realign stack after we pushed callee-saved registers (so that we'll be
// able to calculate their offsets from the frame pointer).
-
- // NOTE: We push the registers before realigning the stack, so
- // vector callee-saved (xmm) registers may be saved w/o proper
- // alignment in this way. However, currently these regs are saved in
- // stack slots (see X86FrameLowering::spillCalleeSavedRegisters()), so
- // this shouldn't be a problem.
- if (RegInfo->needsStackRealignment(MF)) {
+ // Don't do this for Win64, it needs to realign the stack after the prologue.
+ if (!IsWin64Prologue && !IsFunclet && TRI->needsStackRealignment(MF)) {
assert(HasFP && "There should be a frame pointer if stack is realigned.");
- MachineInstr *MI =
- BuildMI(MBB, MBBI, DL,
- TII.get(Is64Bit ? X86::AND64ri32 : X86::AND32ri), StackPtr)
- .addReg(StackPtr)
- .addImm(-MaxAlign)
- .setMIFlag(MachineInstr::FrameSetup);
-
- // The EFLAGS implicit def is dead.
- MI->getOperand(3).setIsDead();
+ BuildStackAlignAND(MBB, MBBI, DL, StackPtr, MaxAlign);
}
// 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);
+ NumBytes -= mergeSPUpdates(MBB, MBBI, true);
// Adjust stack pointer: ESP -= numbytes.
// 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.isTargetCOFF() && !STI.isTargetEnvMacho()) {
- const char *StackProbeSymbol;
- bool isSPUpdateNeeded = false;
-
- if (Is64Bit) {
- if (STI.isTargetCygMing())
- StackProbeSymbol = "___chkstk";
- else {
- StackProbeSymbol = "__chkstk";
- isSPUpdateNeeded = true;
- }
- } else if (STI.isTargetCygMing())
- StackProbeSymbol = "_alloca";
- else
- StackProbeSymbol = "_chkstk";
-
- // Check whether EAX is livein for this function.
- bool isEAXAlive = isEAXLiveIn(MF);
+ uint64_t AlignedNumBytes = NumBytes;
+ if (IsWin64Prologue && !IsFunclet && TRI->needsStackRealignment(MF))
+ AlignedNumBytes = RoundUpToAlignment(AlignedNumBytes, MaxAlign);
+ if (AlignedNumBytes >= StackProbeSize && UseStackProbe) {
+ // Check whether EAX is livein for this block.
+ bool isEAXAlive = isEAXLiveIn(MBB);
if (isEAXAlive) {
// Sanity check that EAX is not livein for this function.
if (Is64Bit) {
// 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::MOV64ri), X86::RAX)
- .addImm(NumBytes)
- .setMIFlag(MachineInstr::FrameSetup);
+ if (isUInt<32>(NumBytes)) {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
+ .addImm(NumBytes)
+ .setMIFlag(MachineInstr::FrameSetup);
+ } else if (isInt<32>(NumBytes)) {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64ri32), X86::RAX)
+ .addImm(NumBytes)
+ .setMIFlag(MachineInstr::FrameSetup);
+ } else {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64ri), X86::RAX)
+ .addImm(NumBytes)
+ .setMIFlag(MachineInstr::FrameSetup);
+ }
} else {
// Allocate NumBytes-4 bytes on stack in case of isEAXAlive.
// We'll also use 4 already allocated bytes for EAX.
BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
- .addImm(isEAXAlive ? NumBytes - 4 : NumBytes)
+ .addImm(isEAXAlive ? NumBytes - 4 : NumBytes)
+ .setMIFlag(MachineInstr::FrameSetup);
+ }
+
+ // Call __chkstk, __chkstk_ms, or __alloca.
+ emitStackProbe(MF, MBB, MBBI, DL, true);
+
+ if (isEAXAlive) {
+ // Restore EAX
+ MachineInstr *MI =
+ addRegOffset(BuildMI(MF, DL, TII.get(X86::MOV32rm), X86::EAX),
+ StackPtr, false, NumBytes - 4);
+ MI->setFlag(MachineInstr::FrameSetup);
+ MBB.insert(MBBI, MI);
+ }
+ } else if (NumBytes) {
+ emitSPUpdate(MBB, MBBI, -(int64_t)NumBytes, /*InEpilogue=*/false);
+ }
+
+ if (NeedsWinCFI && NumBytes)
+ BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_StackAlloc))
+ .addImm(NumBytes)
.setMIFlag(MachineInstr::FrameSetup);
+
+ int SEHFrameOffset = 0;
+ unsigned SPOrEstablisher;
+ if (IsFunclet) {
+ if (IsClrFunclet) {
+ // The establisher parameter passed to a CLR funclet is actually a pointer
+ // to the (mostly empty) frame of its nearest enclosing funclet; we have
+ // to find the root function establisher frame by loading the PSPSym from
+ // the intermediate frame.
+ unsigned PSPSlotOffset = getPSPSlotOffsetFromSP(MF);
+ MachinePointerInfo NoInfo;
+ MBB.addLiveIn(Establisher);
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64rm), Establisher),
+ Establisher, false, PSPSlotOffset)
+ .addMemOperand(MF.getMachineMemOperand(
+ NoInfo, MachineMemOperand::MOLoad, SlotSize, SlotSize));
+ ;
+ // Save the root establisher back into the current funclet's (mostly
+ // empty) frame, in case a sub-funclet or the GC needs it.
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64mr)), StackPtr,
+ false, PSPSlotOffset)
+ .addReg(Establisher)
+ .addMemOperand(
+ MF.getMachineMemOperand(NoInfo, MachineMemOperand::MOStore |
+ MachineMemOperand::MOVolatile,
+ SlotSize, SlotSize));
}
+ SPOrEstablisher = Establisher;
+ } else {
+ SPOrEstablisher = StackPtr;
+ }
- BuildMI(MBB, MBBI, DL,
- TII.get(Is64Bit ? X86::W64ALLOCA : X86::CALLpcrel32))
- .addExternalSymbol(StackProbeSymbol)
- .addReg(StackPtr, RegState::Define | RegState::Implicit)
- .addReg(X86::EFLAGS, RegState::Define | RegState::Implicit)
- .setMIFlag(MachineInstr::FrameSetup);
+ if (IsWin64Prologue && HasFP) {
+ // Set RBP to a small fixed offset from RSP. In the funclet case, we base
+ // this calculation on the incoming establisher, which holds the value of
+ // RSP from the parent frame at the end of the prologue.
+ SEHFrameOffset = calculateSetFPREG(ParentFrameNumBytes);
+ if (SEHFrameOffset)
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::LEA64r), FramePtr),
+ SPOrEstablisher, false, SEHFrameOffset);
+ else
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64rr), FramePtr)
+ .addReg(SPOrEstablisher);
+
+ // If this is not a funclet, emit the CFI describing our frame pointer.
+ if (NeedsWinCFI && !IsFunclet) {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_SetFrame))
+ .addImm(FramePtr)
+ .addImm(SEHFrameOffset)
+ .setMIFlag(MachineInstr::FrameSetup);
+ if (isAsynchronousEHPersonality(Personality))
+ MF.getWinEHFuncInfo()->SEHSetFrameOffset = SEHFrameOffset;
+ }
+ } else if (IsFunclet && STI.is32Bit()) {
+ // Reset EBP / ESI to something good for funclets.
+ MBBI = restoreWin32EHStackPointers(MBB, MBBI, DL);
+ // If we're a catch funclet, we can be returned to via catchret. Save ESP
+ // into the registration node so that the runtime will restore it for us.
+ if (!MBB.isCleanupFuncletEntry()) {
+ assert(Personality == EHPersonality::MSVC_CXX);
+ unsigned FrameReg;
+ int FI = MF.getWinEHFuncInfo()->EHRegNodeFrameIndex;
+ int64_t EHRegOffset = getFrameIndexReference(MF, FI, FrameReg);
+ // ESP is the first field, so no extra displacement is needed.
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32mr)), FrameReg,
+ false, EHRegOffset)
+ .addReg(X86::ESP);
+ }
+ }
- // MSVC x64's __chkstk needs to adjust %rsp.
- // FIXME: %rax preserves the offset and should be available.
- if (isSPUpdateNeeded)
- emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit,
- UseLEA, TII, *RegInfo);
+ while (MBBI != MBB.end() && MBBI->getFlag(MachineInstr::FrameSetup)) {
+ const MachineInstr *FrameInstr = &*MBBI;
+ ++MBBI;
- if (isEAXAlive) {
- // Restore EAX
- MachineInstr *MI = addRegOffset(BuildMI(MF, DL, TII.get(X86::MOV32rm),
- X86::EAX),
- StackPtr, false, NumBytes - 4);
- MI->setFlag(MachineInstr::FrameSetup);
- MBB.insert(MBBI, MI);
+ if (NeedsWinCFI) {
+ int FI;
+ if (unsigned Reg = TII.isStoreToStackSlot(FrameInstr, FI)) {
+ if (X86::FR64RegClass.contains(Reg)) {
+ unsigned IgnoredFrameReg;
+ int Offset = getFrameIndexReference(MF, FI, IgnoredFrameReg);
+ Offset += SEHFrameOffset;
+
+ BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_SaveXMM))
+ .addImm(Reg)
+ .addImm(Offset)
+ .setMIFlag(MachineInstr::FrameSetup);
+ }
+ }
}
- } else if (NumBytes)
- emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit,
- UseLEA, TII, *RegInfo);
+ }
+
+ if (NeedsWinCFI)
+ BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_EndPrologue))
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ if (FnHasClrFunclet && !IsFunclet) {
+ // Save the so-called Initial-SP (i.e. the value of the stack pointer
+ // immediately after the prolog) into the PSPSlot so that funclets
+ // and the GC can recover it.
+ unsigned PSPSlotOffset = getPSPSlotOffsetFromSP(MF);
+ auto PSPInfo = MachinePointerInfo::getFixedStack(
+ MF, MF.getWinEHFuncInfo()->PSPSymFrameIdx);
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64mr)), StackPtr, false,
+ PSPSlotOffset)
+ .addReg(StackPtr)
+ .addMemOperand(MF.getMachineMemOperand(
+ PSPInfo, MachineMemOperand::MOStore | MachineMemOperand::MOVolatile,
+ SlotSize, SlotSize));
+ }
+
+ // Realign stack after we spilled callee-saved registers (so that we'll be
+ // able to calculate their offsets from the frame pointer).
+ // Win64 requires aligning the stack after the prologue.
+ if (IsWin64Prologue && TRI->needsStackRealignment(MF)) {
+ assert(HasFP && "There should be a frame pointer if stack is realigned.");
+ BuildStackAlignAND(MBB, MBBI, DL, SPOrEstablisher, MaxAlign);
+ }
+
+ // We already dealt with stack realignment and funclets above.
+ if (IsFunclet && STI.is32Bit())
+ return;
// If we need a base pointer, set it up here. It's whatever the value
// of the stack pointer is at this point. Any variable size objects
// will be allocated after this, so we can still use the base pointer
// to reference locals.
- if (RegInfo->hasBasePointer(MF)) {
- // Update the frame pointer with the current stack pointer.
- unsigned Opc = Is64Bit ? X86::MOV64rr : X86::MOV32rr;
+ if (TRI->hasBasePointer(MF)) {
+ // Update the base pointer with the current stack pointer.
+ unsigned Opc = Uses64BitFramePtr ? X86::MOV64rr : X86::MOV32rr;
BuildMI(MBB, MBBI, DL, TII.get(Opc), BasePtr)
- .addReg(StackPtr)
+ .addReg(SPOrEstablisher)
.setMIFlag(MachineInstr::FrameSetup);
+ if (X86FI->getRestoreBasePointer()) {
+ // Stash value of base pointer. Saving RSP instead of EBP shortens
+ // dependence chain. Used by SjLj EH.
+ unsigned Opm = Uses64BitFramePtr ? X86::MOV64mr : X86::MOV32mr;
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(Opm)),
+ FramePtr, true, X86FI->getRestoreBasePointerOffset())
+ .addReg(SPOrEstablisher)
+ .setMIFlag(MachineInstr::FrameSetup);
+ }
+
+ if (X86FI->getHasSEHFramePtrSave() && !IsFunclet) {
+ // Stash the value of the frame pointer relative to the base pointer for
+ // Win32 EH. This supports Win32 EH, which does the inverse of the above:
+ // it recovers the frame pointer from the base pointer rather than the
+ // other way around.
+ unsigned Opm = Uses64BitFramePtr ? X86::MOV64mr : X86::MOV32mr;
+ unsigned UsedReg;
+ int Offset =
+ getFrameIndexReference(MF, X86FI->getSEHFramePtrSaveIndex(), UsedReg);
+ assert(UsedReg == BasePtr);
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(Opm)), UsedReg, true, Offset)
+ .addReg(FramePtr)
+ .setMIFlag(MachineInstr::FrameSetup);
+ }
}
- if (( (!HasFP && NumBytes) || PushedRegs) && needsFrameMoves) {
+ if (((!HasFP && NumBytes) || PushedRegs) && NeedsDwarfCFI) {
// 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));
- }
+ assert(StackSize);
+ BuildCFI(MBB, MBBI, DL, MCCFIInstruction::createDefCfaOffset(
+ nullptr, -StackSize + stackGrowth));
}
// Emit DWARF info specifying the offsets of the callee-saved registers.
if (PushedRegs)
- emitCalleeSavedFrameMoves(MF, Label, HasFP ? FramePtr : StackPtr);
+ emitCalleeSavedFrameMoves(MBB, MBBI, DL);
+ }
+}
+
+bool X86FrameLowering::canUseLEAForSPInEpilogue(
+ 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.getTarget().getMCAsmInfo()->usesWindowsCFI() || hasFP(MF);
+}
+
+static bool isFuncletReturnInstr(MachineInstr *MI) {
+ switch (MI->getOpcode()) {
+ case X86::CATCHRET:
+ case X86::CLEANUPRET:
+ return true;
+ default:
+ return false;
}
+ llvm_unreachable("impossible");
+}
- // Darwin 10.7 and greater has support for compact unwind encoding.
- if (STI.getTargetTriple().isMacOSX() &&
- !STI.getTargetTriple().isMacOSXVersionLT(10, 7))
- MMI.setCompactUnwindEncoding(getCompactUnwindEncoding(MF));
+// CLR funclets use a special "Previous Stack Pointer Symbol" slot on the
+// stack. It holds a pointer to the bottom of the root function frame. The
+// establisher frame pointer passed to a nested funclet may point to the
+// (mostly empty) frame of its parent funclet, but it will need to find
+// the frame of the root function to access locals. To facilitate this,
+// every funclet copies the pointer to the bottom of the root function
+// frame into a PSPSym slot in its own (mostly empty) stack frame. Using the
+// same offset for the PSPSym in the root function frame that's used in the
+// funclets' frames allows each funclet to dynamically accept any ancestor
+// frame as its establisher argument (the runtime doesn't guarantee the
+// immediate parent for some reason lost to history), and also allows the GC,
+// which uses the PSPSym for some bookkeeping, to find it in any funclet's
+// frame with only a single offset reported for the entire method.
+unsigned
+X86FrameLowering::getPSPSlotOffsetFromSP(const MachineFunction &MF) const {
+ const WinEHFuncInfo &Info = *MF.getWinEHFuncInfo();
+ // getFrameIndexReferenceFromSP has an out ref parameter for the stack
+ // pointer register; pass a dummy that we ignore
+ unsigned SPReg;
+ int Offset = getFrameIndexReferenceFromSP(MF, Info.PSPSymFrameIdx, SPReg);
+ assert(Offset >= 0);
+ return static_cast<unsigned>(Offset);
+}
+
+unsigned
+X86FrameLowering::getWinEHFuncletFrameSize(const MachineFunction &MF) const {
+ // This is the size of the pushed CSRs.
+ unsigned CSSize =
+ MF.getInfo<X86MachineFunctionInfo>()->getCalleeSavedFrameSize();
+ // This is the amount of stack a funclet needs to allocate.
+ unsigned UsedSize;
+ EHPersonality Personality =
+ classifyEHPersonality(MF.getFunction()->getPersonalityFn());
+ if (Personality == EHPersonality::CoreCLR) {
+ // CLR funclets need to hold enough space to include the PSPSym, at the
+ // same offset from the stack pointer (immediately after the prolog) as it
+ // resides at in the main function.
+ UsedSize = getPSPSlotOffsetFromSP(MF) + SlotSize;
+ } else {
+ // Other funclets just need enough stack for outgoing call arguments.
+ UsedSize = MF.getFrameInfo()->getMaxCallFrameSize();
+ }
+ // RBP is not included in the callee saved register block. After pushing RBP,
+ // everything is 16 byte aligned. Everything we allocate before an outgoing
+ // call must also be 16 byte aligned.
+ unsigned FrameSizeMinusRBP =
+ RoundUpToAlignment(CSSize + UsedSize, getStackAlignment());
+ // Subtract out the size of the callee saved registers. This is how much stack
+ // each funclet will allocate.
+ return FrameSizeMinusRBP - CSSize;
}
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();
- bool UseLEA = STI.useLeaForSP();
- 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
- }
+ MachineBasicBlock::iterator MBBI = MBB.getFirstTerminator();
+ DebugLoc DL;
+ if (MBBI != MBB.end())
+ DL = MBBI->getDebugLoc();
+ // standard x86_64 and NaCl use 64-bit frame/stack pointers, x32 - 32-bit.
+ const bool Is64BitILP32 = STI.isTarget64BitILP32();
+ unsigned FramePtr = TRI->getFrameRegister(MF);
+ unsigned MachineFramePtr =
+ Is64BitILP32 ? getX86SubSuperRegister(FramePtr, 64) : FramePtr;
+
+ bool IsWin64Prologue = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
+ bool NeedsWinCFI =
+ IsWin64Prologue && MF.getFunction()->needsUnwindTableEntry();
+ bool IsFunclet = isFuncletReturnInstr(MBBI);
+ MachineBasicBlock *TargetMBB = nullptr;
// Get the number of bytes to allocate from the FrameInfo.
uint64_t StackSize = MFI->getStackSize();
- uint64_t MaxAlign = MFI->getMaxAlignment();
+ uint64_t MaxAlign = calculateMaxStackAlign(MF);
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 (MBBI->getOpcode() == X86::CATCHRET) {
+ // SEH shouldn't use catchret.
+ assert(!isAsynchronousEHPersonality(
+ classifyEHPersonality(MF.getFunction()->getPersonalityFn())) &&
+ "SEH should not use CATCHRET");
- if (hasFP(MF)) {
+ NumBytes = getWinEHFuncletFrameSize(MF);
+ assert(hasFP(MF) && "EH funclets without FP not yet implemented");
+ TargetMBB = MBBI->getOperand(0).getMBB();
+
+ // Pop EBP.
+ BuildMI(MBB, MBBI, DL, TII.get(Is64Bit ? X86::POP64r : X86::POP32r),
+ MachineFramePtr)
+ .setMIFlag(MachineInstr::FrameDestroy);
+ } else if (MBBI->getOpcode() == X86::CLEANUPRET) {
+ NumBytes = getWinEHFuncletFrameSize(MF);
+ assert(hasFP(MF) && "EH funclets without FP not yet implemented");
+ BuildMI(MBB, MBBI, DL, TII.get(Is64Bit ? X86::POP64r : X86::POP32r),
+ MachineFramePtr)
+ .setMIFlag(MachineInstr::FrameDestroy);
+ } else if (hasFP(MF)) {
// Calculate required stack adjustment.
uint64_t FrameSize = StackSize - SlotSize;
- if (RegInfo->needsStackRealignment(MF)) {
- // Callee-saved registers were pushed on stack before the stack
- // was realigned.
- FrameSize -= CSSize;
- NumBytes = (FrameSize + MaxAlign - 1) / MaxAlign * MaxAlign;
- } else {
- NumBytes = FrameSize - CSSize;
- }
+ NumBytes = FrameSize - CSSize;
+
+ // Callee-saved registers were pushed on stack before the stack was
+ // realigned.
+ if (TRI->needsStackRealignment(MF) && !IsWin64Prologue)
+ NumBytes = RoundUpToAlignment(FrameSize, MaxAlign);
// Pop EBP.
BuildMI(MBB, MBBI, DL,
- TII.get(Is64Bit ? X86::POP64r : X86::POP32r), FramePtr);
+ TII.get(Is64Bit ? X86::POP64r : X86::POP32r), MachineFramePtr)
+ .setMIFlag(MachineInstr::FrameDestroy);
} else {
NumBytes = StackSize - CSSize;
}
+ uint64_t SEHStackAllocAmt = NumBytes;
// Skip the callee-saved pop instructions.
while (MBBI != MBB.begin()) {
- MachineBasicBlock::iterator PI = prior(MBBI);
+ MachineBasicBlock::iterator PI = std::prev(MBBI);
unsigned Opc = PI->getOpcode();
- if (Opc != X86::POP32r && Opc != X86::POP64r && Opc != X86::DBG_VALUE &&
- !PI->isTerminator())
+ if ((Opc != X86::POP32r || !PI->getFlag(MachineInstr::FrameDestroy)) &&
+ (Opc != X86::POP64r || !PI->getFlag(MachineInstr::FrameDestroy)) &&
+ Opc != X86::DBG_VALUE && !PI->isTerminator())
break;
--MBBI;
}
MachineBasicBlock::iterator FirstCSPop = MBBI;
- DL = MBBI->getDebugLoc();
+ if (TargetMBB) {
+ // Fill EAX/RAX with the address of the target block.
+ unsigned ReturnReg = STI.is64Bit() ? X86::RAX : X86::EAX;
+ if (STI.is64Bit()) {
+ // LEA64r TargetMBB(%rip), %rax
+ BuildMI(MBB, FirstCSPop, DL, TII.get(X86::LEA64r), ReturnReg)
+ .addReg(X86::RIP)
+ .addImm(0)
+ .addReg(0)
+ .addMBB(TargetMBB)
+ .addReg(0);
+ } else {
+ // MOV32ri $TargetMBB, %eax
+ BuildMI(MBB, FirstCSPop, DL, TII.get(X86::MOV32ri), ReturnReg)
+ .addMBB(TargetMBB);
+ }
+ // Record that we've taken the address of TargetMBB and no longer just
+ // reference it in a terminator.
+ TargetMBB->setHasAddressTaken();
+ }
+
+ if (MBBI != MBB.end())
+ 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);
+ NumBytes += mergeSPUpdates(MBB, MBBI, true);
// 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) || MFI->hasVarSizedObjects()) {
- if (RegInfo->needsStackRealignment(MF))
+ // realigned. Don't do this if this was a funclet epilogue, since the funclets
+ // will not do realignment or dynamic stack allocation.
+ if ((TRI->needsStackRealignment(MF) || MFI->hasVarSizedObjects()) &&
+ !IsFunclet) {
+ if (TRI->needsStackRealignment(MF))
MBBI = FirstCSPop;
- if (CSSize != 0) {
- unsigned Opc = getLEArOpcode(Is64Bit);
+ unsigned SEHFrameOffset = calculateSetFPREG(SEHStackAllocAmt);
+ uint64_t LEAAmount =
+ IsWin64Prologue ? SEHStackAllocAmt - SEHFrameOffset : -CSSize;
+
+ // There are only two legal forms of epilogue:
+ // - add SEHAllocationSize, %rsp
+ // - lea SEHAllocationSize(%FramePtr), %rsp
+ //
+ // 'mov %FramePtr, %rsp' will not be recognized as an epilogue sequence.
+ // However, we may use this sequence if we have a frame pointer because the
+ // effects of the prologue can safely be undone.
+ if (LEAAmount != 0) {
+ unsigned Opc = getLEArOpcode(Uses64BitFramePtr);
addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr),
- FramePtr, false, -CSSize);
+ FramePtr, false, LEAAmount);
+ --MBBI;
} else {
- unsigned Opc = (Is64Bit ? X86::MOV64rr : X86::MOV32rr);
+ unsigned Opc = (Uses64BitFramePtr ? X86::MOV64rr : X86::MOV32rr);
BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr)
.addReg(FramePtr);
+ --MBBI;
}
} else if (NumBytes) {
// Adjust stack pointer back: ESP += numbytes.
- emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, UseLEA, TII, *RegInfo);
+ emitSPUpdate(MBB, MBBI, NumBytes, /*InEpilogue=*/true);
+ --MBBI;
}
- // 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 preceding ADD instruction.
- Offset += mergeSPUpdates(MBB, MBBI, StackPtr, true);
- emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, UseLEA, 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);
- NewMI->copyImplicitOps(MF, MBBI);
-
- // 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();
+ // Windows unwinder will not invoke function's exception handler if IP is
+ // either in prologue or in epilogue. This behavior causes a problem when a
+ // call immediately precedes an epilogue, because the return address points
+ // into the epilogue. To cope with that, we insert an epilogue marker here,
+ // then replace it with a 'nop' if it ends up immediately after a CALL in the
+ // final emitted code.
+ if (NeedsWinCFI)
+ 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();
// Check for possible merge with preceding ADD instruction.
- delta += mergeSPUpdates(MBB, MBBI, StackPtr, true);
- emitSPUpdate(MBB, MBBI, StackPtr, delta, Is64Bit, UseLEA, TII, *RegInfo);
+ Offset += mergeSPUpdates(MBB, MBBI, true);
+ emitSPUpdate(MBB, MBBI, Offset, /*InEpilogue=*/true);
}
}
-int X86FrameLowering::getFrameIndexOffset(const MachineFunction &MF, int FI) const {
- const X86RegisterInfo *RegInfo =
- static_cast<const X86RegisterInfo*>(MF.getTarget().getRegisterInfo());
+// NOTE: this only has a subset of the full frame index logic. In
+// particular, the FI < 0 and AfterFPPop logic is handled in
+// X86RegisterInfo::eliminateFrameIndex, but not here. Possibly
+// (probably?) it should be moved into here.
+int X86FrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
+ unsigned &FrameReg) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
+
+ // We can't calculate offset from frame pointer if the stack is realigned,
+ // so enforce usage of stack/base pointer. The base pointer is used when we
+ // have dynamic allocas in addition to dynamic realignment.
+ if (TRI->hasBasePointer(MF))
+ FrameReg = TRI->getBaseRegister();
+ else if (TRI->needsStackRealignment(MF))
+ FrameReg = TRI->getStackRegister();
+ else
+ FrameReg = TRI->getFrameRegister(MF);
+
+ // Offset will hold the offset from the stack pointer at function entry to the
+ // object.
+ // We need to factor in additional offsets applied during the prologue to the
+ // frame, base, and stack pointer depending on which is used.
int Offset = MFI->getObjectOffset(FI) - getOffsetOfLocalArea();
+ const X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
+ unsigned CSSize = X86FI->getCalleeSavedFrameSize();
uint64_t StackSize = MFI->getStackSize();
+ bool HasFP = hasFP(MF);
+ bool IsWin64Prologue = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
+ int64_t FPDelta = 0;
+
+ if (IsWin64Prologue) {
+ assert(!MFI->hasCalls() || (StackSize % 16) == 8);
- if (RegInfo->hasBasePointer(MF)) {
- assert (hasFP(MF) && "VLAs and dynamic stack realign, but no FP?!");
+ // Calculate required stack adjustment.
+ uint64_t FrameSize = StackSize - SlotSize;
+ // If required, include space for extra hidden slot for stashing base pointer.
+ if (X86FI->getRestoreBasePointer())
+ FrameSize += SlotSize;
+ uint64_t NumBytes = FrameSize - CSSize;
+
+ uint64_t SEHFrameOffset = calculateSetFPREG(NumBytes);
+ if (FI && FI == X86FI->getFAIndex())
+ return -SEHFrameOffset;
+
+ // FPDelta is the offset from the "traditional" FP location of the old base
+ // pointer followed by return address and the location required by the
+ // restricted Win64 prologue.
+ // Add FPDelta to all offsets below that go through the frame pointer.
+ FPDelta = FrameSize - SEHFrameOffset;
+ assert((!MFI->hasCalls() || (FPDelta % 16) == 0) &&
+ "FPDelta isn't aligned per the Win64 ABI!");
+ }
+
+
+ if (TRI->hasBasePointer(MF)) {
+ assert(HasFP && "VLAs and dynamic stack realign, but no FP?!");
if (FI < 0) {
// Skip the saved EBP.
- return Offset + RegInfo->getSlotSize();
+ return Offset + SlotSize + FPDelta;
} else {
assert((-(Offset + StackSize)) % MFI->getObjectAlignment(FI) == 0);
return Offset + StackSize;
}
- } else if (RegInfo->needsStackRealignment(MF)) {
+ } else if (TRI->needsStackRealignment(MF)) {
if (FI < 0) {
// Skip the saved EBP.
- return Offset + RegInfo->getSlotSize();
+ return Offset + SlotSize + FPDelta;
} else {
assert((-(Offset + StackSize)) % MFI->getObjectAlignment(FI) == 0);
return Offset + StackSize;
}
// FIXME: Support tail calls
} else {
- if (!hasFP(MF))
+ if (!HasFP)
return Offset + StackSize;
// Skip the saved EBP.
- Offset += RegInfo->getSlotSize();
+ Offset += SlotSize;
// Skip the RETADDR move area
- const X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0)
Offset -= TailCallReturnAddrDelta;
}
- return Offset;
+ return Offset + FPDelta;
}
-int X86FrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
- unsigned &FrameReg) const {
- const X86RegisterInfo *RegInfo =
- static_cast<const X86RegisterInfo*>(MF.getTarget().getRegisterInfo());
- // We can't calculate offset from frame pointer if the stack is realigned,
- // so enforce usage of stack/base pointer. The base pointer is used when we
- // have dynamic allocas in addition to dynamic realignment.
- if (RegInfo->hasBasePointer(MF))
- FrameReg = RegInfo->getBaseRegister();
- else if (RegInfo->needsStackRealignment(MF))
- FrameReg = RegInfo->getStackRegister();
- else
- FrameReg = RegInfo->getFrameRegister(MF);
- return getFrameIndexOffset(MF, FI);
-}
+// Simplified from getFrameIndexReference keeping only StackPointer cases
+int X86FrameLowering::getFrameIndexReferenceFromSP(const MachineFunction &MF,
+ int FI,
+ unsigned &FrameReg) const {
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+ // Does not include any dynamic realign.
+ const uint64_t StackSize = MFI->getStackSize();
+ {
+#ifndef NDEBUG
+ // LLVM arranges the stack as follows:
+ // ...
+ // ARG2
+ // ARG1
+ // RETADDR
+ // PUSH RBP <-- RBP points here
+ // PUSH CSRs
+ // ~~~~~~~ <-- possible stack realignment (non-win64)
+ // ...
+ // STACK OBJECTS
+ // ... <-- RSP after prologue points here
+ // ~~~~~~~ <-- possible stack realignment (win64)
+ //
+ // if (hasVarSizedObjects()):
+ // ... <-- "base pointer" (ESI/RBX) points here
+ // DYNAMIC ALLOCAS
+ // ... <-- RSP points here
+ //
+ // Case 1: In the simple case of no stack realignment and no dynamic
+ // allocas, both "fixed" stack objects (arguments and CSRs) are addressable
+ // with fixed offsets from RSP.
+ //
+ // Case 2: In the case of stack realignment with no dynamic allocas, fixed
+ // stack objects are addressed with RBP and regular stack objects with RSP.
+ //
+ // Case 3: In the case of dynamic allocas and stack realignment, RSP is used
+ // to address stack arguments for outgoing calls and nothing else. The "base
+ // pointer" points to local variables, and RBP points to fixed objects.
+ //
+ // In cases 2 and 3, we can only answer for non-fixed stack objects, and the
+ // answer we give is relative to the SP after the prologue, and not the
+ // SP in the middle of the function.
+
+ assert((!MFI->isFixedObjectIndex(FI) || !TRI->needsStackRealignment(MF) ||
+ STI.isTargetWin64()) &&
+ "offset from fixed object to SP is not static");
+
+ // We don't handle tail calls, and shouldn't be seeing them either.
+ int TailCallReturnAddrDelta =
+ MF.getInfo<X86MachineFunctionInfo>()->getTCReturnAddrDelta();
+ assert(!(TailCallReturnAddrDelta < 0) && "we don't handle this case!");
+#endif
+ }
-bool X86FrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator MI,
- const std::vector<CalleeSavedInfo> &CSI,
- const TargetRegisterInfo *TRI) const {
- if (CSI.empty())
- return false;
+ // Fill in FrameReg output argument.
+ FrameReg = TRI->getStackRegister();
- DebugLoc DL = MBB.findDebugLoc(MI);
+ // This is how the math works out:
+ //
+ // %rsp grows (i.e. gets lower) left to right. Each box below is
+ // one word (eight bytes). Obj0 is the stack slot we're trying to
+ // get to.
+ //
+ // ----------------------------------
+ // | BP | Obj0 | Obj1 | ... | ObjN |
+ // ----------------------------------
+ // ^ ^ ^ ^
+ // A B C E
+ //
+ // A is the incoming stack pointer.
+ // (B - A) is the local area offset (-8 for x86-64) [1]
+ // (C - A) is the Offset returned by MFI->getObjectOffset for Obj0 [2]
+ //
+ // |(E - B)| is the StackSize (absolute value, positive). For a
+ // stack that grown down, this works out to be (B - E). [3]
+ //
+ // E is also the value of %rsp after stack has been set up, and we
+ // want (C - E) -- the value we can add to %rsp to get to Obj0. Now
+ // (C - E) == (C - A) - (B - A) + (B - E)
+ // { Using [1], [2] and [3] above }
+ // == getObjectOffset - LocalAreaOffset + StackSize
+ //
- MachineFunction &MF = *MBB.getParent();
+ // Get the Offset from the StackPointer
+ int Offset = MFI->getObjectOffset(FI) - getOffsetOfLocalArea();
- unsigned SlotSize = STI.is64Bit() ? 8 : 4;
- unsigned FPReg = TRI->getFrameRegister(MF);
- unsigned CalleeFrameSize = 0;
+ return Offset + StackSize;
+}
- const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
+bool X86FrameLowering::assignCalleeSavedSpillSlots(
+ MachineFunction &MF, const TargetRegisterInfo *TRI,
+ std::vector<CalleeSavedInfo> &CSI) const {
+ MachineFrameInfo *MFI = MF.getFrameInfo();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
+ unsigned CalleeSavedFrameSize = 0;
+ int SpillSlotOffset = getOffsetOfLocalArea() + X86FI->getTCReturnAddrDelta();
+
+ if (hasFP(MF)) {
+ // emitPrologue always spills frame register the first thing.
+ SpillSlotOffset -= SlotSize;
+ MFI->CreateFixedSpillStackObject(SlotSize, SpillSlotOffset);
+
+ // Since emitPrologue and emitEpilogue will handle spilling and restoring of
+ // the frame register, we can delete it from CSI list and not have to worry
+ // about avoiding it later.
+ unsigned FPReg = TRI->getFrameRegister(MF);
+ for (unsigned i = 0; i < CSI.size(); ++i) {
+ if (TRI->regsOverlap(CSI[i].getReg(),FPReg)) {
+ CSI.erase(CSI.begin() + i);
+ break;
+ }
+ }
+ }
+
+ // Assign slots for GPRs. It increases frame size.
+ for (unsigned i = CSI.size(); i != 0; --i) {
+ unsigned Reg = CSI[i - 1].getReg();
+
+ if (!X86::GR64RegClass.contains(Reg) && !X86::GR32RegClass.contains(Reg))
+ continue;
+
+ SpillSlotOffset -= SlotSize;
+ CalleeSavedFrameSize += SlotSize;
+
+ int SlotIndex = MFI->CreateFixedSpillStackObject(SlotSize, SpillSlotOffset);
+ CSI[i - 1].setFrameIdx(SlotIndex);
+ }
+
+ X86FI->setCalleeSavedFrameSize(CalleeSavedFrameSize);
+
+ // Assign slots for XMMs.
+ for (unsigned i = CSI.size(); i != 0; --i) {
+ unsigned Reg = CSI[i - 1].getReg();
+ if (X86::GR64RegClass.contains(Reg) || X86::GR32RegClass.contains(Reg))
+ continue;
+
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ // ensure alignment
+ SpillSlotOffset -= std::abs(SpillSlotOffset) % RC->getAlignment();
+ // spill into slot
+ SpillSlotOffset -= RC->getSize();
+ int SlotIndex =
+ MFI->CreateFixedSpillStackObject(RC->getSize(), SpillSlotOffset);
+ CSI[i - 1].setFrameIdx(SlotIndex);
+ MFI->ensureMaxAlignment(RC->getAlignment());
+ }
+
+ return true;
+}
+
+bool X86FrameLowering::spillCalleeSavedRegisters(
+ MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
+ const std::vector<CalleeSavedInfo> &CSI,
+ const TargetRegisterInfo *TRI) const {
+ DebugLoc DL = MBB.findDebugLoc(MI);
+
+ // Don't save CSRs in 32-bit EH funclets. The caller saves EBX, EBP, ESI, EDI
+ // for us, and there are no XMM CSRs on Win32.
+ if (MBB.isEHFuncletEntry() && STI.is32Bit() && STI.isOSWindows())
+ return true;
+
// Push GPRs. It increases frame size.
unsigned Opc = STI.is64Bit() ? X86::PUSH64r : X86::PUSH32r;
for (unsigned i = CSI.size(); i != 0; --i) {
- unsigned Reg = CSI[i-1].getReg();
- if (!X86::GR64RegClass.contains(Reg) &&
- !X86::GR32RegClass.contains(Reg))
+ unsigned Reg = CSI[i - 1].getReg();
+
+ if (!X86::GR64RegClass.contains(Reg) && !X86::GR32RegClass.contains(Reg))
continue;
// 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;
- CalleeFrameSize += SlotSize;
+
BuildMI(MBB, MI, DL, TII.get(Opc)).addReg(Reg, RegState::Kill)
.setMIFlag(MachineInstr::FrameSetup);
}
- X86FI->setCalleeSavedFrameSize(CalleeFrameSize);
-
// Make XMM regs spilled. X86 does not have ability of push/pop XMM.
// It can be done by spilling XMMs to stack frame.
- // Note that only Win64 ABI might spill XMMs.
for (unsigned i = CSI.size(); i != 0; --i) {
unsigned Reg = CSI[i-1].getReg();
- if (X86::GR64RegClass.contains(Reg) ||
- X86::GR32RegClass.contains(Reg))
+ if (X86::GR64RegClass.contains(Reg) || X86::GR32RegClass.contains(Reg))
continue;
// Add the callee-saved register as live-in. It's killed at the spill.
MBB.addLiveIn(Reg);
const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
- TII.storeRegToStackSlot(MBB, MI, Reg, true, CSI[i-1].getFrameIdx(),
- RC, TRI);
+
+ TII.storeRegToStackSlot(MBB, MI, Reg, true, CSI[i - 1].getFrameIdx(), RC,
+ TRI);
+ --MI;
+ MI->setFlag(MachineInstr::FrameSetup);
+ ++MI;
}
return true;
if (CSI.empty())
return false;
- DebugLoc DL = MBB.findDebugLoc(MI);
+ if (isFuncletReturnInstr(MI) && STI.isOSWindows()) {
+ // Don't restore CSRs in 32-bit EH funclets. Matches
+ // spillCalleeSavedRegisters.
+ if (STI.is32Bit())
+ return true;
+ // Don't restore CSRs before an SEH catchret. SEH except blocks do not form
+ // funclets. emitEpilogue transforms these to normal jumps.
+ if (MI->getOpcode() == X86::CATCHRET) {
+ const Function *Func = MBB.getParent()->getFunction();
+ bool IsSEH = isAsynchronousEHPersonality(
+ classifyEHPersonality(Func->getPersonalityFn()));
+ if (IsSEH)
+ return true;
+ }
+ }
- MachineFunction &MF = *MBB.getParent();
- const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
+ DebugLoc DL = MBB.findDebugLoc(MI);
// Reload XMMs from stack frame.
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
if (X86::GR64RegClass.contains(Reg) ||
X86::GR32RegClass.contains(Reg))
continue;
+
const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
- TII.loadRegFromStackSlot(MBB, MI, Reg, CSI[i].getFrameIdx(),
- RC, TRI);
+ TII.loadRegFromStackSlot(MBB, MI, Reg, CSI[i].getFrameIdx(), RC, TRI);
}
// POP GPRs.
- unsigned FPReg = TRI->getFrameRegister(MF);
unsigned Opc = STI.is64Bit() ? X86::POP64r : X86::POP32r;
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
unsigned Reg = CSI[i].getReg();
if (!X86::GR64RegClass.contains(Reg) &&
!X86::GR32RegClass.contains(Reg))
continue;
- if (Reg == FPReg)
- // X86RegisterInfo::emitEpilogue will handle restoring of frame register.
- continue;
- BuildMI(MBB, MI, DL, TII.get(Opc), Reg);
+
+ BuildMI(MBB, MI, DL, TII.get(Opc), Reg)
+ .setMIFlag(MachineInstr::FrameDestroy);
}
return true;
}
-void
-X86FrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
- RegScavenger *RS) const {
+void X86FrameLowering::determineCalleeSaves(MachineFunction &MF,
+ BitVector &SavedRegs,
+ RegScavenger *RS) const {
+ TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
+
MachineFrameInfo *MFI = MF.getFrameInfo();
- const X86RegisterInfo *RegInfo = TM.getRegisterInfo();
- unsigned SlotSize = RegInfo->getSlotSize();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
- int32_t TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
+ int64_t TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0) {
// create RETURNADDR 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!");
- (void)FrameIdx;
+ TailCallReturnAddrDelta - SlotSize, true);
}
// Spill the BasePtr if it's used.
- if (RegInfo->hasBasePointer(MF))
- MF.getRegInfo().setPhysRegUsed(RegInfo->getBaseRegister());
+ if (TRI->hasBasePointer(MF)) {
+ SavedRegs.set(TRI->getBaseRegister());
+
+ // Allocate a spill slot for EBP if we have a base pointer and EH funclets.
+ if (MF.getMMI().hasEHFunclets()) {
+ int FI = MFI->CreateSpillStackObject(SlotSize, SlotSize);
+ X86FI->setHasSEHFramePtrSave(true);
+ X86FI->setSEHFramePtrSaveIndex(FI);
+ }
+ }
}
static bool
return false;
}
-
-/// GetScratchRegister - Get a register for performing work in the segmented
-/// stack prologue. Depending on platform and the properties of the function
-/// either one or two registers will be needed. Set primary to true for
-/// the first register, false for the second.
+/// GetScratchRegister - Get a temp register for performing work in the
+/// segmented stack and the Erlang/HiPE stack prologue. Depending on platform
+/// and the properties of the function either one or two registers will be
+/// needed. Set primary to true for the first register, false for the second.
static unsigned
-GetScratchRegister(bool Is64Bit, const MachineFunction &MF, bool Primary) {
- if (Is64Bit)
- return Primary ? X86::R11 : X86::R12;
-
+GetScratchRegister(bool Is64Bit, bool IsLP64, const MachineFunction &MF, bool Primary) {
CallingConv::ID CallingConvention = MF.getFunction()->getCallingConv();
+
+ // Erlang stuff.
+ if (CallingConvention == CallingConv::HiPE) {
+ if (Is64Bit)
+ return Primary ? X86::R14 : X86::R13;
+ else
+ return Primary ? X86::EBX : X86::EDI;
+ }
+
+ if (Is64Bit) {
+ if (IsLP64)
+ return Primary ? X86::R11 : X86::R12;
+ else
+ return Primary ? X86::R11D : X86::R12D;
+ }
+
bool IsNested = HasNestArgument(&MF);
if (CallingConvention == CallingConv::X86_FastCall ||
// limit.
static const uint64_t kSplitStackAvailable = 256;
-void
-X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const {
- MachineBasicBlock &prologueMBB = MF.front();
+void X86FrameLowering::adjustForSegmentedStacks(
+ MachineFunction &MF, MachineBasicBlock &PrologueMBB) const {
MachineFrameInfo *MFI = MF.getFrameInfo();
- const X86InstrInfo &TII = *TM.getInstrInfo();
uint64_t StackSize;
- bool Is64Bit = STI.is64Bit();
unsigned TlsReg, TlsOffset;
DebugLoc DL;
- const X86Subtarget *ST = &MF.getTarget().getSubtarget<X86Subtarget>();
- unsigned ScratchReg = GetScratchRegister(Is64Bit, MF, true);
+ // To support shrink-wrapping we would need to insert the new blocks
+ // at the right place and update the branches to PrologueMBB.
+ assert(&(*MF.begin()) == &PrologueMBB && "Shrink-wrapping not supported yet");
+
+ unsigned ScratchReg = GetScratchRegister(Is64Bit, IsLP64, MF, true);
assert(!MF.getRegInfo().isLiveIn(ScratchReg) &&
"Scratch register is live-in");
if (MF.getFunction()->isVarArg())
report_fatal_error("Segmented stacks do not support vararg functions.");
- if (!ST->isTargetLinux() && !ST->isTargetDarwin() &&
- !ST->isTargetWin32() && !ST->isTargetFreeBSD())
+ if (!STI.isTargetLinux() && !STI.isTargetDarwin() && !STI.isTargetWin32() &&
+ !STI.isTargetWin64() && !STI.isTargetFreeBSD() &&
+ !STI.isTargetDragonFly())
report_fatal_error("Segmented stacks not supported on this platform.");
+ // Eventually StackSize will be calculated by a link-time pass; which will
+ // also decide whether checking code needs to be injected into this particular
+ // prologue.
+ StackSize = MFI->getStackSize();
+
+ // Do not generate a prologue for functions with a stack of size zero
+ if (StackSize == 0)
+ return;
+
MachineBasicBlock *allocMBB = MF.CreateMachineBasicBlock();
MachineBasicBlock *checkMBB = MF.CreateMachineBasicBlock();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
// The MOV R10, RAX needs to be in a different block, since the RET we emit in
// allocMBB needs to be last (terminating) instruction.
- for (MachineBasicBlock::livein_iterator i = prologueMBB.livein_begin(),
- e = prologueMBB.livein_end(); i != e; i++) {
- allocMBB->addLiveIn(*i);
- checkMBB->addLiveIn(*i);
+ for (const auto &LI : PrologueMBB.liveins()) {
+ allocMBB->addLiveIn(LI);
+ checkMBB->addLiveIn(LI);
}
if (IsNested)
- allocMBB->addLiveIn(X86::R10);
+ allocMBB->addLiveIn(IsLP64 ? X86::R10 : X86::R10D);
MF.push_front(allocMBB);
MF.push_front(checkMBB);
- // Eventually StackSize will be calculated by a link-time pass; which will
- // also decide whether checking code needs to be injected into this particular
- // prologue.
- StackSize = MFI->getStackSize();
-
// When the frame size is less than 256 we just compare the stack
// boundary directly to the value of the stack pointer, per gcc.
bool CompareStackPointer = StackSize < kSplitStackAvailable;
// Read the limit off the current stacklet off the stack_guard location.
if (Is64Bit) {
- if (ST->isTargetLinux()) {
+ if (STI.isTargetLinux()) {
TlsReg = X86::FS;
- TlsOffset = 0x70;
- } else if (ST->isTargetDarwin()) {
+ TlsOffset = IsLP64 ? 0x70 : 0x40;
+ } else if (STI.isTargetDarwin()) {
TlsReg = X86::GS;
TlsOffset = 0x60 + 90*8; // See pthread_machdep.h. Steal TLS slot 90.
- } else if (ST->isTargetFreeBSD()) {
+ } else if (STI.isTargetWin64()) {
+ TlsReg = X86::GS;
+ TlsOffset = 0x28; // pvArbitrary, reserved for application use
+ } else if (STI.isTargetFreeBSD()) {
TlsReg = X86::FS;
TlsOffset = 0x18;
+ } else if (STI.isTargetDragonFly()) {
+ TlsReg = X86::FS;
+ TlsOffset = 0x20; // use tls_tcb.tcb_segstack
} else {
report_fatal_error("Segmented stacks not supported on this platform.");
}
if (CompareStackPointer)
- ScratchReg = X86::RSP;
+ ScratchReg = IsLP64 ? X86::RSP : X86::ESP;
else
- BuildMI(checkMBB, DL, TII.get(X86::LEA64r), ScratchReg).addReg(X86::RSP)
+ BuildMI(checkMBB, DL, TII.get(IsLP64 ? X86::LEA64r : X86::LEA64_32r), ScratchReg).addReg(X86::RSP)
.addImm(1).addReg(0).addImm(-StackSize).addReg(0);
- BuildMI(checkMBB, DL, TII.get(X86::CMP64rm)).addReg(ScratchReg)
+ BuildMI(checkMBB, DL, TII.get(IsLP64 ? X86::CMP64rm : X86::CMP32rm)).addReg(ScratchReg)
.addReg(0).addImm(1).addReg(0).addImm(TlsOffset).addReg(TlsReg);
} else {
- if (ST->isTargetLinux()) {
+ if (STI.isTargetLinux()) {
TlsReg = X86::GS;
TlsOffset = 0x30;
- } else if (ST->isTargetDarwin()) {
+ } else if (STI.isTargetDarwin()) {
TlsReg = X86::GS;
TlsOffset = 0x48 + 90*4;
- } else if (ST->isTargetWin32()) {
+ } else if (STI.isTargetWin32()) {
TlsReg = X86::FS;
TlsOffset = 0x14; // pvArbitrary, reserved for application use
- } else if (ST->isTargetFreeBSD()) {
+ } else if (STI.isTargetDragonFly()) {
+ TlsReg = X86::FS;
+ TlsOffset = 0x10; // use tls_tcb.tcb_segstack
+ } else if (STI.isTargetFreeBSD()) {
report_fatal_error("Segmented stacks not supported on FreeBSD i386.");
} else {
report_fatal_error("Segmented stacks not supported on this platform.");
BuildMI(checkMBB, DL, TII.get(X86::LEA32r), ScratchReg).addReg(X86::ESP)
.addImm(1).addReg(0).addImm(-StackSize).addReg(0);
- if (ST->isTargetLinux() || ST->isTargetWin32()) {
+ if (STI.isTargetLinux() || STI.isTargetWin32() || STI.isTargetWin64() ||
+ STI.isTargetDragonFly()) {
BuildMI(checkMBB, DL, TII.get(X86::CMP32rm)).addReg(ScratchReg)
.addReg(0).addImm(0).addReg(0).addImm(TlsOffset).addReg(TlsReg);
- } else if (ST->isTargetDarwin()) {
+ } else if (STI.isTargetDarwin()) {
- // TlsOffset doesn't fit into a mod r/m byte so we need an extra register
+ // TlsOffset doesn't fit into a mod r/m byte so we need an extra register.
unsigned ScratchReg2;
bool SaveScratch2;
if (CompareStackPointer) {
- // The primary scratch register is available for holding the TLS offset
- ScratchReg2 = GetScratchRegister(Is64Bit, MF, true);
+ // The primary scratch register is available for holding the TLS offset.
+ ScratchReg2 = GetScratchRegister(Is64Bit, IsLP64, MF, true);
SaveScratch2 = false;
} else {
// Need to use a second register to hold the TLS offset
- ScratchReg2 = GetScratchRegister(Is64Bit, MF, false);
+ ScratchReg2 = GetScratchRegister(Is64Bit, IsLP64, MF, false);
- // Unfortunately, with fastcc the second scratch register may hold an arg
+ // Unfortunately, with fastcc the second scratch register may hold an
+ // argument.
SaveScratch2 = MF.getRegInfo().isLiveIn(ScratchReg2);
}
- // If Scratch2 is live-in then it needs to be saved
+ // If Scratch2 is live-in then it needs to be saved.
assert((!MF.getRegInfo().isLiveIn(ScratchReg2) || SaveScratch2) &&
"Scratch register is live-in and not saved");
// This jump is taken if SP >= (Stacklet Limit + Stack Space required).
// It jumps to normal execution of the function body.
- BuildMI(checkMBB, DL, TII.get(X86::JA_4)).addMBB(&prologueMBB);
+ BuildMI(checkMBB, DL, TII.get(X86::JA_1)).addMBB(&PrologueMBB);
// On 32 bit we first push the arguments size and then the frame size. On 64
// bit, we pass the stack frame size in r10 and the argument size in r11.
// Functions with nested arguments use R10, so it needs to be saved across
// the call to _morestack
+ const unsigned RegAX = IsLP64 ? X86::RAX : X86::EAX;
+ const unsigned Reg10 = IsLP64 ? X86::R10 : X86::R10D;
+ const unsigned Reg11 = IsLP64 ? X86::R11 : X86::R11D;
+ const unsigned MOVrr = IsLP64 ? X86::MOV64rr : X86::MOV32rr;
+ const unsigned MOVri = IsLP64 ? X86::MOV64ri : X86::MOV32ri;
+
if (IsNested)
- BuildMI(allocMBB, DL, TII.get(X86::MOV64rr), X86::RAX).addReg(X86::R10);
+ BuildMI(allocMBB, DL, TII.get(MOVrr), RegAX).addReg(Reg10);
- BuildMI(allocMBB, DL, TII.get(X86::MOV64ri), X86::R10)
+ BuildMI(allocMBB, DL, TII.get(MOVri), Reg10)
.addImm(StackSize);
- BuildMI(allocMBB, DL, TII.get(X86::MOV64ri), X86::R11)
+ BuildMI(allocMBB, DL, TII.get(MOVri), Reg11)
.addImm(X86FI->getArgumentStackSize());
- MF.getRegInfo().setPhysRegUsed(X86::R10);
- MF.getRegInfo().setPhysRegUsed(X86::R11);
} else {
BuildMI(allocMBB, DL, TII.get(X86::PUSHi32))
.addImm(X86FI->getArgumentStackSize());
}
// __morestack is in libgcc
- if (Is64Bit)
- BuildMI(allocMBB, DL, TII.get(X86::CALL64pcrel32))
- .addExternalSymbol("__morestack");
- else
- BuildMI(allocMBB, DL, TII.get(X86::CALLpcrel32))
- .addExternalSymbol("__morestack");
+ if (Is64Bit && MF.getTarget().getCodeModel() == CodeModel::Large) {
+ // Under the large code model, we cannot assume that __morestack lives
+ // within 2^31 bytes of the call site, so we cannot use pc-relative
+ // addressing. We cannot perform the call via a temporary register,
+ // as the rax register may be used to store the static chain, and all
+ // other suitable registers may be either callee-save or used for
+ // parameter passing. We cannot use the stack at this point either
+ // because __morestack manipulates the stack directly.
+ //
+ // To avoid these issues, perform an indirect call via a read-only memory
+ // location containing the address.
+ //
+ // This solution is not perfect, as it assumes that the .rodata section
+ // is laid out within 2^31 bytes of each function body, but this seems
+ // to be sufficient for JIT.
+ BuildMI(allocMBB, DL, TII.get(X86::CALL64m))
+ .addReg(X86::RIP)
+ .addImm(0)
+ .addReg(0)
+ .addExternalSymbol("__morestack_addr")
+ .addReg(0);
+ MF.getMMI().setUsesMorestackAddr(true);
+ } else {
+ if (Is64Bit)
+ BuildMI(allocMBB, DL, TII.get(X86::CALL64pcrel32))
+ .addExternalSymbol("__morestack");
+ else
+ BuildMI(allocMBB, DL, TII.get(X86::CALLpcrel32))
+ .addExternalSymbol("__morestack");
+ }
if (IsNested)
BuildMI(allocMBB, DL, TII.get(X86::MORESTACK_RET_RESTORE_R10));
else
BuildMI(allocMBB, DL, TII.get(X86::MORESTACK_RET));
- allocMBB->addSuccessor(&prologueMBB);
+ allocMBB->addSuccessor(&PrologueMBB);
checkMBB->addSuccessor(allocMBB);
- checkMBB->addSuccessor(&prologueMBB);
+ checkMBB->addSuccessor(&PrologueMBB);
#ifdef XDEBUG
MF.verify();
#endif
}
+
+/// Erlang programs may need a special prologue to handle the stack size they
+/// might need at runtime. That is because Erlang/OTP does not implement a C
+/// stack but uses a custom implementation of hybrid stack/heap architecture.
+/// (for more information see Eric Stenman's Ph.D. thesis:
+/// http://publications.uu.se/uu/fulltext/nbn_se_uu_diva-2688.pdf)
+///
+/// CheckStack:
+/// temp0 = sp - MaxStack
+/// if( temp0 < SP_LIMIT(P) ) goto IncStack else goto OldStart
+/// OldStart:
+/// ...
+/// IncStack:
+/// call inc_stack # doubles the stack space
+/// temp0 = sp - MaxStack
+/// if( temp0 < SP_LIMIT(P) ) goto IncStack else goto OldStart
+void X86FrameLowering::adjustForHiPEPrologue(
+ MachineFunction &MF, MachineBasicBlock &PrologueMBB) const {
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ DebugLoc DL;
+
+ // To support shrink-wrapping we would need to insert the new blocks
+ // at the right place and update the branches to PrologueMBB.
+ assert(&(*MF.begin()) == &PrologueMBB && "Shrink-wrapping not supported yet");
+
+ // HiPE-specific values
+ const unsigned HipeLeafWords = 24;
+ const unsigned CCRegisteredArgs = Is64Bit ? 6 : 5;
+ const unsigned Guaranteed = HipeLeafWords * SlotSize;
+ unsigned CallerStkArity = MF.getFunction()->arg_size() > CCRegisteredArgs ?
+ MF.getFunction()->arg_size() - CCRegisteredArgs : 0;
+ unsigned MaxStack = MFI->getStackSize() + CallerStkArity*SlotSize + SlotSize;
+
+ assert(STI.isTargetLinux() &&
+ "HiPE prologue is only supported on Linux operating systems.");
+
+ // Compute the largest caller's frame that is needed to fit the callees'
+ // frames. This 'MaxStack' is computed from:
+ //
+ // a) the fixed frame size, which is the space needed for all spilled temps,
+ // b) outgoing on-stack parameter areas, and
+ // c) the minimum stack space this function needs to make available for the
+ // functions it calls (a tunable ABI property).
+ if (MFI->hasCalls()) {
+ unsigned MoreStackForCalls = 0;
+
+ for (MachineFunction::iterator MBBI = MF.begin(), MBBE = MF.end();
+ MBBI != MBBE; ++MBBI)
+ for (MachineBasicBlock::iterator MI = MBBI->begin(), ME = MBBI->end();
+ MI != ME; ++MI) {
+ if (!MI->isCall())
+ continue;
+
+ // Get callee operand.
+ const MachineOperand &MO = MI->getOperand(0);
+
+ // Only take account of global function calls (no closures etc.).
+ if (!MO.isGlobal())
+ continue;
+
+ const Function *F = dyn_cast<Function>(MO.getGlobal());
+ if (!F)
+ continue;
+
+ // Do not update 'MaxStack' for primitive and built-in functions
+ // (encoded with names either starting with "erlang."/"bif_" or not
+ // having a ".", such as a simple <Module>.<Function>.<Arity>, or an
+ // "_", such as the BIF "suspend_0") as they are executed on another
+ // stack.
+ if (F->getName().find("erlang.") != StringRef::npos ||
+ F->getName().find("bif_") != StringRef::npos ||
+ F->getName().find_first_of("._") == StringRef::npos)
+ continue;
+
+ unsigned CalleeStkArity =
+ F->arg_size() > CCRegisteredArgs ? F->arg_size()-CCRegisteredArgs : 0;
+ if (HipeLeafWords - 1 > CalleeStkArity)
+ MoreStackForCalls = std::max(MoreStackForCalls,
+ (HipeLeafWords - 1 - CalleeStkArity) * SlotSize);
+ }
+ MaxStack += MoreStackForCalls;
+ }
+
+ // If the stack frame needed is larger than the guaranteed then runtime checks
+ // and calls to "inc_stack_0" BIF should be inserted in the assembly prologue.
+ if (MaxStack > Guaranteed) {
+ MachineBasicBlock *stackCheckMBB = MF.CreateMachineBasicBlock();
+ MachineBasicBlock *incStackMBB = MF.CreateMachineBasicBlock();
+
+ for (const auto &LI : PrologueMBB.liveins()) {
+ stackCheckMBB->addLiveIn(LI);
+ incStackMBB->addLiveIn(LI);
+ }
+
+ MF.push_front(incStackMBB);
+ MF.push_front(stackCheckMBB);
+
+ unsigned ScratchReg, SPReg, PReg, SPLimitOffset;
+ unsigned LEAop, CMPop, CALLop;
+ if (Is64Bit) {
+ SPReg = X86::RSP;
+ PReg = X86::RBP;
+ LEAop = X86::LEA64r;
+ CMPop = X86::CMP64rm;
+ CALLop = X86::CALL64pcrel32;
+ SPLimitOffset = 0x90;
+ } else {
+ SPReg = X86::ESP;
+ PReg = X86::EBP;
+ LEAop = X86::LEA32r;
+ CMPop = X86::CMP32rm;
+ CALLop = X86::CALLpcrel32;
+ SPLimitOffset = 0x4c;
+ }
+
+ ScratchReg = GetScratchRegister(Is64Bit, IsLP64, MF, true);
+ assert(!MF.getRegInfo().isLiveIn(ScratchReg) &&
+ "HiPE prologue scratch register is live-in");
+
+ // Create new MBB for StackCheck:
+ addRegOffset(BuildMI(stackCheckMBB, DL, TII.get(LEAop), ScratchReg),
+ SPReg, false, -MaxStack);
+ // SPLimitOffset is in a fixed heap location (pointed by BP).
+ addRegOffset(BuildMI(stackCheckMBB, DL, TII.get(CMPop))
+ .addReg(ScratchReg), PReg, false, SPLimitOffset);
+ BuildMI(stackCheckMBB, DL, TII.get(X86::JAE_1)).addMBB(&PrologueMBB);
+
+ // Create new MBB for IncStack:
+ BuildMI(incStackMBB, DL, TII.get(CALLop)).
+ addExternalSymbol("inc_stack_0");
+ addRegOffset(BuildMI(incStackMBB, DL, TII.get(LEAop), ScratchReg),
+ SPReg, false, -MaxStack);
+ addRegOffset(BuildMI(incStackMBB, DL, TII.get(CMPop))
+ .addReg(ScratchReg), PReg, false, SPLimitOffset);
+ BuildMI(incStackMBB, DL, TII.get(X86::JLE_1)).addMBB(incStackMBB);
+
+ stackCheckMBB->addSuccessor(&PrologueMBB, {99, 100});
+ stackCheckMBB->addSuccessor(incStackMBB, {1, 100});
+ incStackMBB->addSuccessor(&PrologueMBB, {99, 100});
+ incStackMBB->addSuccessor(incStackMBB, {1, 100});
+ }
+#ifdef XDEBUG
+ MF.verify();
+#endif
+}
+
+bool X86FrameLowering::adjustStackWithPops(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MBBI, DebugLoc DL, int Offset) const {
+
+ if (Offset <= 0)
+ return false;
+
+ if (Offset % SlotSize)
+ return false;
+
+ int NumPops = Offset / SlotSize;
+ // This is only worth it if we have at most 2 pops.
+ if (NumPops != 1 && NumPops != 2)
+ return false;
+
+ // Handle only the trivial case where the adjustment directly follows
+ // a call. This is the most common one, anyway.
+ if (MBBI == MBB.begin())
+ return false;
+ MachineBasicBlock::iterator Prev = std::prev(MBBI);
+ if (!Prev->isCall() || !Prev->getOperand(1).isRegMask())
+ return false;
+
+ unsigned Regs[2];
+ unsigned FoundRegs = 0;
+
+ auto RegMask = Prev->getOperand(1);
+
+ auto &RegClass =
+ Is64Bit ? X86::GR64_NOREX_NOSPRegClass : X86::GR32_NOREX_NOSPRegClass;
+ // Try to find up to NumPops free registers.
+ for (auto Candidate : RegClass) {
+
+ // Poor man's liveness:
+ // Since we're immediately after a call, any register that is clobbered
+ // by the call and not defined by it can be considered dead.
+ if (!RegMask.clobbersPhysReg(Candidate))
+ continue;
+
+ bool IsDef = false;
+ for (const MachineOperand &MO : Prev->implicit_operands()) {
+ if (MO.isReg() && MO.isDef() && MO.getReg() == Candidate) {
+ IsDef = true;
+ break;
+ }
+ }
+
+ if (IsDef)
+ continue;
+
+ Regs[FoundRegs++] = Candidate;
+ if (FoundRegs == (unsigned)NumPops)
+ break;
+ }
+
+ if (FoundRegs == 0)
+ return false;
+
+ // If we found only one free register, but need two, reuse the same one twice.
+ while (FoundRegs < (unsigned)NumPops)
+ Regs[FoundRegs++] = Regs[0];
+
+ for (int i = 0; i < NumPops; ++i)
+ BuildMI(MBB, MBBI, DL,
+ TII.get(STI.is64Bit() ? X86::POP64r : X86::POP32r), Regs[i]);
+
+ return true;
+}
+
+void X86FrameLowering::
+eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator I) const {
+ bool reserveCallFrame = hasReservedCallFrame(MF);
+ unsigned Opcode = I->getOpcode();
+ bool isDestroy = Opcode == TII.getCallFrameDestroyOpcode();
+ DebugLoc DL = I->getDebugLoc();
+ uint64_t Amount = !reserveCallFrame ? I->getOperand(0).getImm() : 0;
+ uint64_t InternalAmt = (isDestroy || Amount) ? I->getOperand(1).getImm() : 0;
+ I = MBB.erase(I);
+
+ if (!reserveCallFrame) {
+ // If the stack pointer can be changed after prologue, turn the
+ // adjcallstackup instruction into a 'sub ESP, <amt>' and the
+ // adjcallstackdown instruction into 'add ESP, <amt>'
+
+ // 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.
+ unsigned StackAlign = getStackAlignment();
+ Amount = RoundUpToAlignment(Amount, StackAlign);
+
+ MachineModuleInfo &MMI = MF.getMMI();
+ const Function *Fn = MF.getFunction();
+ bool WindowsCFI = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
+ bool DwarfCFI = !WindowsCFI &&
+ (MMI.hasDebugInfo() || Fn->needsUnwindTableEntry());
+
+ // If we have any exception handlers in this function, and we adjust
+ // the SP before calls, we may need to indicate this to the unwinder
+ // using GNU_ARGS_SIZE. Note that this may be necessary even when
+ // Amount == 0, because the preceding function may have set a non-0
+ // GNU_ARGS_SIZE.
+ // TODO: We don't need to reset this between subsequent functions,
+ // if it didn't change.
+ bool HasDwarfEHHandlers = !WindowsCFI &&
+ !MF.getMMI().getLandingPads().empty();
+
+ if (HasDwarfEHHandlers && !isDestroy &&
+ MF.getInfo<X86MachineFunctionInfo>()->getHasPushSequences())
+ BuildCFI(MBB, I, DL,
+ MCCFIInstruction::createGnuArgsSize(nullptr, Amount));
+
+ if (Amount == 0)
+ return;
+
+ // Factor out the amount that gets handled inside the sequence
+ // (Pushes of argument for frame setup, callee pops for frame destroy)
+ Amount -= InternalAmt;
+
+ // TODO: This is needed only if we require precise CFA.
+ // If this is a callee-pop calling convention, emit a CFA adjust for
+ // the amount the callee popped.
+ if (isDestroy && InternalAmt && DwarfCFI && !hasFP(MF))
+ BuildCFI(MBB, I, DL,
+ MCCFIInstruction::createAdjustCfaOffset(nullptr, -InternalAmt));
+
+ if (Amount) {
+ // Add Amount to SP to destroy a frame, and subtract to setup.
+ int Offset = isDestroy ? Amount : -Amount;
+
+ if (!(Fn->optForMinSize() &&
+ adjustStackWithPops(MBB, I, DL, Offset)))
+ BuildStackAdjustment(MBB, I, DL, Offset, /*InEpilogue=*/false);
+ }
+
+ if (DwarfCFI && !hasFP(MF)) {
+ // If we don't have FP, but need to generate unwind information,
+ // we need to set the correct CFA offset after the stack adjustment.
+ // How much we adjust the CFA offset depends on whether we're emitting
+ // CFI only for EH purposes or for debugging. EH only requires the CFA
+ // offset to be correct at each call site, while for debugging we want
+ // it to be more precise.
+ int CFAOffset = Amount;
+ // TODO: When not using precise CFA, we also need to adjust for the
+ // InternalAmt here.
+
+ if (CFAOffset) {
+ CFAOffset = isDestroy ? -CFAOffset : CFAOffset;
+ BuildCFI(MBB, I, DL,
+ MCCFIInstruction::createAdjustCfaOffset(nullptr, CFAOffset));
+ }
+ }
+
+ return;
+ }
+
+ if (isDestroy && InternalAmt) {
+ // If we are performing frame pointer elimination and if the callee pops
+ // something off the stack pointer, add it back. We do this until we have
+ // more advanced stack pointer tracking ability.
+ // We are not tracking the stack pointer adjustment by the callee, so make
+ // sure we restore the stack pointer immediately after the call, there may
+ // be spill code inserted between the CALL and ADJCALLSTACKUP instructions.
+ MachineBasicBlock::iterator B = MBB.begin();
+ while (I != B && !std::prev(I)->isCall())
+ --I;
+ BuildStackAdjustment(MBB, I, DL, -InternalAmt, /*InEpilogue=*/false);
+ }
+}
+
+bool X86FrameLowering::canUseAsEpilogue(const MachineBasicBlock &MBB) const {
+ assert(MBB.getParent() && "Block is not attached to a function!");
+
+ // Win64 has strict requirements in terms of epilogue and we are
+ // not taking a chance at messing with them.
+ // I.e., unless this block is already an exit block, we can't use
+ // it as an epilogue.
+ if (STI.isTargetWin64() && !MBB.succ_empty() && !MBB.isReturnBlock())
+ return false;
+
+ if (canUseLEAForSPInEpilogue(*MBB.getParent()))
+ return true;
+
+ // If we cannot use LEA to adjust SP, we may need to use ADD, which
+ // clobbers the EFLAGS. Check that we do not need to preserve it,
+ // otherwise, conservatively assume this is not
+ // safe to insert the epilogue here.
+ return !flagsNeedToBePreservedBeforeTheTerminators(MBB);
+}
+
+bool X86FrameLowering::enableShrinkWrapping(const MachineFunction &MF) const {
+ // If we may need to emit frameless compact unwind information, give
+ // up as this is currently broken: PR25614.
+ return (MF.getFunction()->hasFnAttribute(Attribute::NoUnwind) || hasFP(MF)) &&
+ // The lowering of segmented stack and HiPE only support entry blocks
+ // as prologue blocks: PR26107.
+ // This limitation may be lifted if we fix:
+ // - adjustForSegmentedStacks
+ // - adjustForHiPEPrologue
+ MF.getFunction()->getCallingConv() != CallingConv::HiPE &&
+ !MF.shouldSplitStack();
+}
+
+MachineBasicBlock::iterator X86FrameLowering::restoreWin32EHStackPointers(
+ MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
+ DebugLoc DL, bool RestoreSP) const {
+ assert(STI.isTargetWindowsMSVC() && "funclets only supported in MSVC env");
+ assert(STI.isTargetWin32() && "EBP/ESI restoration only required on win32");
+ assert(STI.is32Bit() && !Uses64BitFramePtr &&
+ "restoring EBP/ESI on non-32-bit target");
+
+ MachineFunction &MF = *MBB.getParent();
+ unsigned FramePtr = TRI->getFrameRegister(MF);
+ unsigned BasePtr = TRI->getBaseRegister();
+ WinEHFuncInfo &FuncInfo = *MF.getWinEHFuncInfo();
+ X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+
+ // FIXME: Don't set FrameSetup flag in catchret case.
+
+ int FI = FuncInfo.EHRegNodeFrameIndex;
+ int EHRegSize = MFI->getObjectSize(FI);
+
+ if (RestoreSP) {
+ // MOV32rm -EHRegSize(%ebp), %esp
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32rm), X86::ESP),
+ X86::EBP, true, -EHRegSize)
+ .setMIFlag(MachineInstr::FrameSetup);
+ }
+
+ unsigned UsedReg;
+ int EHRegOffset = getFrameIndexReference(MF, FI, UsedReg);
+ int EndOffset = -EHRegOffset - EHRegSize;
+ FuncInfo.EHRegNodeEndOffset = EndOffset;
+
+ if (UsedReg == FramePtr) {
+ // ADD $offset, %ebp
+ unsigned ADDri = getADDriOpcode(false, EndOffset);
+ BuildMI(MBB, MBBI, DL, TII.get(ADDri), FramePtr)
+ .addReg(FramePtr)
+ .addImm(EndOffset)
+ .setMIFlag(MachineInstr::FrameSetup)
+ ->getOperand(3)
+ .setIsDead();
+ assert(EndOffset >= 0 &&
+ "end of registration object above normal EBP position!");
+ } else if (UsedReg == BasePtr) {
+ // LEA offset(%ebp), %esi
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::LEA32r), BasePtr),
+ FramePtr, false, EndOffset)
+ .setMIFlag(MachineInstr::FrameSetup);
+ // MOV32rm SavedEBPOffset(%esi), %ebp
+ assert(X86FI->getHasSEHFramePtrSave());
+ int Offset =
+ getFrameIndexReference(MF, X86FI->getSEHFramePtrSaveIndex(), UsedReg);
+ assert(UsedReg == BasePtr);
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32rm), FramePtr),
+ UsedReg, true, Offset)
+ .setMIFlag(MachineInstr::FrameSetup);
+ } else {
+ llvm_unreachable("32-bit frames with WinEH must use FramePtr or BasePtr");
+ }
+ return MBBI;
+}
+
+unsigned X86FrameLowering::getWinEHParentFrameOffset(const MachineFunction &MF) const {
+ // RDX, the parent frame pointer, is homed into 16(%rsp) in the prologue.
+ unsigned Offset = 16;
+ // RBP is immediately pushed.
+ Offset += SlotSize;
+ // All callee-saved registers are then pushed.
+ Offset += MF.getInfo<X86MachineFunctionInfo>()->getCalleeSavedFrameSize();
+ // Every funclet allocates enough stack space for the largest outgoing call.
+ Offset += getWinEHFuncletFrameSize(MF);
+ return Offset;
+}
+
+void X86FrameLowering::processFunctionBeforeFrameFinalized(
+ MachineFunction &MF, RegScavenger *RS) const {
+ // If this function isn't doing Win64-style C++ EH, we don't need to do
+ // anything.
+ const Function *Fn = MF.getFunction();
+ if (!STI.is64Bit() || !MF.getMMI().hasEHFunclets() ||
+ classifyEHPersonality(Fn->getPersonalityFn()) != EHPersonality::MSVC_CXX)
+ return;
+
+ // Win64 C++ EH needs to allocate the UnwindHelp object at some fixed offset
+ // relative to RSP after the prologue. Find the offset of the last fixed
+ // object, so that we can allocate a slot immediately following it. If there
+ // were no fixed objects, use offset -SlotSize, which is immediately after the
+ // return address. Fixed objects have negative frame indices.
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ int64_t MinFixedObjOffset = -SlotSize;
+ for (int I = MFI->getObjectIndexBegin(); I < 0; ++I)
+ MinFixedObjOffset = std::min(MinFixedObjOffset, MFI->getObjectOffset(I));
+
+ int64_t UnwindHelpOffset = MinFixedObjOffset - SlotSize;
+ int UnwindHelpFI =
+ MFI->CreateFixedObject(SlotSize, UnwindHelpOffset, /*Immutable=*/false);
+ MF.getWinEHFuncInfo()->UnwindHelpFrameIdx = UnwindHelpFI;
+
+ // Store -2 into UnwindHelp on function entry. We have to scan forwards past
+ // other frame setup instructions.
+ MachineBasicBlock &MBB = MF.front();
+ auto MBBI = MBB.begin();
+ while (MBBI != MBB.end() && MBBI->getFlag(MachineInstr::FrameSetup))
+ ++MBBI;
+
+ DebugLoc DL = MBB.findDebugLoc(MBBI);
+ addFrameReference(BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64mi32)),
+ UnwindHelpFI)
+ .addImm(-2);
+}
projects / oota-llvm.git / blobdiff