#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "llvm/ADT/SmallSet.h"
+#include "llvm/Analysis/LibCallSemantics.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
.addReg(Reg, getDefRegState(!isSub) | getUndefRegState(isSub));
if (isSub)
MI->setFlag(MachineInstr::FrameSetup);
+ else
+ MI->setFlag(MachineInstr::FrameDestroy);
Offset -= ThisVal;
continue;
}
MBB, MBBI, DL, isSub ? -ThisVal : ThisVal, InEpilogue);
if (isSub)
MI.setMIFlag(MachineInstr::FrameSetup);
+ else
+ MI.setMIFlag(MachineInstr::FrameDestroy);
Offset -= ThisVal;
}
const MachineFrameInfo *MFI = MF.getFrameInfo();
uint64_t MaxAlign = MFI->getMaxAlignment(); // Desired stack alignment.
unsigned StackAlign = getStackAlignment();
- if (ForceStackAlign) {
+ if (MF.getFunction()->hasFnAttribute("stackrealign")) {
if (MFI->hasCalls())
MaxAlign = (StackAlign > MaxAlign) ? StackAlign : MaxAlign;
else if (MaxAlign < SlotSize)
void X86FrameLowering::BuildStackAlignAND(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
- DebugLoc DL,
+ DebugLoc DL, unsigned Reg,
uint64_t MaxAlign) const {
uint64_t Val = -MaxAlign;
- MachineInstr *MI =
- BuildMI(MBB, MBBI, DL, TII.get(getANDriOpcode(Uses64BitFramePtr, Val)),
- StackPtr)
- .addReg(StackPtr)
- .addImm(Val)
- .setMIFlag(MachineInstr::FrameSetup);
+ 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();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
uint64_t MaxAlign = calculateMaxStackAlign(MF); // Desired stack alignment.
uint64_t StackSize = MFI->getStackSize(); // Number of bytes to allocate.
+ bool IsFunclet = MBB.isEHFuncletEntry();
+ bool IsClrFunclet =
+ IsFunclet &&
+ classifyEHPersonality(Fn->getPersonalityFn()) == EHPersonality::CoreCLR;
bool HasFP = hasFP(MF);
bool IsWin64CC = STI.isCallingConvWin64(Fn->getCallingConv());
bool IsWin64Prologue = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
? getX86SubSuperRegister(FramePtr, MVT::i64, false)
: 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;
// Add RETADDR move area to callee saved frame size.
uint64_t NumBytes = 0;
int stackGrowth = -SlotSize;
- if (MBB.isEHFuncletEntry()) {
- assert(STI.isOSWindows() && "funclets only supported on Windows");
-
- // Set up the FramePtr and BasePtr physical registers using the address
- // passed as EBP or RDX by the MSVC EH runtime.
- if (STI.is32Bit()) {
- MBBI = restoreWin32EHFrameAndBasePtr(MBB, MBBI, DL);
- } else {
- // FIXME: Add SEH directives.
- NeedsWinCFI = false;
- // Immediately spill RDX into the home slot. The runtime cares about this.
- unsigned RDX = Uses64BitFramePtr ? X86::RDX : X86::EDX;
- // MOV64mr %rdx, 16(%rsp)
- unsigned MOVmr = Uses64BitFramePtr ? X86::MOV64mr : X86::MOV32mr;
- addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(MOVmr)),
- StackPtr, true, 16)
- .addReg(RDX)
+ // 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);
- // PUSH64r %rbp
- BuildMI(MBB, MBBI, DL, TII.get(Is64Bit ? X86::PUSH64r : X86::PUSH32r))
- .addReg(MachineFramePtr, RegState::Kill)
- .setMIFlag(MachineInstr::FrameSetup);
- // MOV64rr %rdx, %rbp
- unsigned MOVrr = Uses64BitFramePtr ? X86::MOV64rr : X86::MOV32rr;
- BuildMI(MBB, MBBI, DL, TII.get(MOVrr), FramePtr)
- .addReg(RDX)
- .setMIFlag(MachineInstr::FrameSetup);
- assert(!TRI->hasBasePointer(MF) &&
- "x64 funclets with base ptrs not yet implemented");
- }
+ MBB.addLiveIn(Establisher);
+ }
- // For EH funclets, only allocate enough space for outgoing calls.
- NumBytes = MFI->getMaxCallFrameSize();
- } else if (HasFP) {
+ if (HasFP) {
// Calculate required stack adjustment.
uint64_t FrameSize = StackSize - SlotSize;
// If required, include space for extra hidden slot for stashing base pointer.
// 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))
.setMIFlag(MachineInstr::FrameSetup);
}
- if (!IsWin64Prologue) {
+ 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));
+ 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.
- for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I)
- I->addLiveIn(MachineFramePtr);
+ // 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;
// Realign stack after we pushed callee-saved registers (so that we'll be
// able to calculate their offsets from the frame pointer).
// Don't do this for Win64, it needs to realign the stack after the prologue.
- if (!IsWin64Prologue && TRI->needsStackRealignment(MF)) {
+ if (!IsWin64Prologue && !IsFunclet && TRI->needsStackRealignment(MF)) {
assert(HasFP && "There should be a frame pointer if stack is realigned.");
- BuildStackAlignAND(MBB, MBBI, DL, MaxAlign);
+ BuildStackAlignAND(MBB, MBBI, DL, StackPtr, MaxAlign);
}
// If there is an SUB32ri of ESP immediately before this instruction, merge
// increments is necessary to ensure that the guard pages used by the OS
// virtual memory manager are allocated in correct sequence.
uint64_t AlignedNumBytes = NumBytes;
- if (IsWin64Prologue && TRI->needsStackRealignment(MF))
+ if (IsWin64Prologue && !IsFunclet && TRI->needsStackRealignment(MF))
AlignedNumBytes = RoundUpToAlignment(AlignedNumBytes, MaxAlign);
if (AlignedNumBytes >= StackProbeSize && UseStackProbe) {
// Check whether EAX is livein for this function.
.setMIFlag(MachineInstr::FrameSetup);
int SEHFrameOffset = 0;
+ unsigned SPOrEstablisher = IsFunclet ? Establisher : StackPtr;
if (IsWin64Prologue && HasFP) {
- SEHFrameOffset = calculateSetFPREG(NumBytes);
+ // 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),
- StackPtr, false, SEHFrameOffset);
+ SPOrEstablisher, false, SEHFrameOffset);
else
- BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64rr), FramePtr).addReg(StackPtr);
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64rr), FramePtr)
+ .addReg(SPOrEstablisher);
- if (NeedsWinCFI)
+ // 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);
+ } else if (IsFunclet && STI.is32Bit()) {
+ // Reset EBP / ESI to something good for funclets.
+ MBBI = restoreWin32EHStackPointers(MBB, MBBI, DL);
}
while (MBBI != MBB.end() && MBBI->getFlag(MachineInstr::FrameSetup)) {
// 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, MaxAlign);
+ 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
// 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
unsigned Opm = Uses64BitFramePtr ? X86::MOV64mr : X86::MOV32mr;
addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(Opm)),
FramePtr, true, X86FI->getRestoreBasePointerOffset())
- .addReg(StackPtr)
+ .addReg(SPOrEstablisher)
.setMIFlag(MachineInstr::FrameSetup);
}
- if (X86FI->getHasSEHFramePtrSave()) {
+ 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
static bool isFuncletReturnInstr(MachineInstr *MI) {
switch (MI->getOpcode()) {
case X86::CATCHRET:
- case X86::CATCHRET64:
+ case X86::CLEANUPRET:
return true;
default:
return false;
llvm_unreachable("impossible");
}
+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 MaxCallSize = 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 + MaxCallSize, 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();
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();
unsigned CSSize = X86FI->getCalleeSavedFrameSize();
uint64_t NumBytes = 0;
- if (isFuncletReturnInstr(MBBI)) {
- NumBytes = MFI->getMaxCallFrameSize();
+ if (MBBI->getOpcode() == X86::CATCHRET) {
+ // SEH shouldn't use catchret.
+ assert(!isAsynchronousEHPersonality(
+ classifyEHPersonality(MF.getFunction()->getPersonalityFn())) &&
+ "SEH should not use CATCHRET");
- if (Is64Bit) {
- assert(hasFP(MF) && "win64 EH funclets without FP not yet implemented");
- // POP64r %rbp
- BuildMI(MBB, MBBI, DL, TII.get(Is64Bit ? X86::POP64r : X86::POP32r),
- MachineFramePtr);
- }
+ 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;
// Pop EBP.
BuildMI(MBB, MBBI, DL,
- TII.get(Is64Bit ? X86::POP64r : X86::POP32r), MachineFramePtr);
+ TII.get(Is64Bit ? X86::POP64r : X86::POP32r), MachineFramePtr)
+ .setMIFlag(MachineInstr::FrameDestroy);
} else {
NumBytes = StackSize - CSSize;
}
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;
+ 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 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 (TRI->needsStackRealignment(MF) || MFI->hasVarSizedObjects()) {
+ // 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;
unsigned SEHFrameOffset = calculateSetFPREG(SEHStackAllocAmt);
const uint64_t StackSize = MFI->getStackSize();
{
#ifndef NDEBUG
- // Note: LLVM arranges the stack as:
- // Args > Saved RetPC (<--FP) > CSRs > dynamic alignment (<--BP)
- // > "Stack Slots" (<--SP)
- // We can always address StackSlots from RSP. We can usually (unless
- // needsStackRealignment) address CSRs from RSP, but sometimes need to
- // address them from RBP. FixedObjects can be placed anywhere in the stack
- // frame depending on their specific requirements (i.e. we can actually
- // refer to arguments to the function which are stored in the *callers*
- // frame). As a result, THE RESULT OF THIS CALL IS MEANINGLESS FOR CSRs
- // AND FixedObjects IFF needsStackRealignment or hasVarSizedObject.
-
- assert(!TRI->hasBasePointer(MF) && "we don't handle this case");
-
- // We don't handle tail calls, and shouldn't be seeing them
- // either.
+ // LLVM arranges the stack as follows:
+ // ...
+ // ARG2
+ // ARG1
+ // RETADDR
+ // PUSH RBP <-- RBP points here
+ // PUSH CSRs
+ // ~~~~~~~ <-- optional stack realignment dynamic adjustment
+ // ...
+ // STACK OBJECTS
+ // ... <-- RSP after prologue points here
+ //
+ // 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((!TRI->needsStackRealignment(MF) || !MFI->isFixedObjectIndex(FI)) &&
+ "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!");
if (CSI.empty())
return false;
- // Don't restore CSRs in 32-bit EH funclets. Matches
- // spillCalleeSavedRegisters.
- if (isFuncletReturnInstr(MI) && STI.is32Bit() && STI.isOSWindows())
- return true;
+ 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;
+ }
+ }
DebugLoc DL = MBB.findDebugLoc(MI);
!X86::GR32RegClass.contains(Reg))
continue;
- BuildMI(MBB, MI, DL, TII.get(Opc), Reg);
+ BuildMI(MBB, MI, DL, TII.get(Opc), Reg)
+ .setMIFlag(MachineInstr::FrameDestroy);
}
return true;
}
// 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 (unsigned LI : PrologueMBB.liveins()) {
+ for (const auto &LI : PrologueMBB.liveins()) {
allocMBB->addLiveIn(LI);
checkMBB->addLiveIn(LI);
}
MachineBasicBlock *stackCheckMBB = MF.CreateMachineBasicBlock();
MachineBasicBlock *incStackMBB = MF.CreateMachineBasicBlock();
- for (unsigned LI : PrologueMBB.liveins()) {
+ for (const auto &LI : PrologueMBB.liveins()) {
stackCheckMBB->addLiveIn(LI);
incStackMBB->addLiveIn(LI);
}
bool X86FrameLowering::adjustStackWithPops(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, DebugLoc DL, int Offset) const {
+ if (Offset <= 0)
+ return false;
+
if (Offset % SlotSize)
return false;
unsigned FoundRegs = 0;
auto RegMask = Prev->getOperand(1);
-
- // Try to find up to NumPops free registers.
- for (auto Candidate : X86::GR32_NOREX_NOSPRegClass) {
+
+ 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
// 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>'
- if (Amount == 0)
- return;
// 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
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;
+ // If this is a callee-pop calling convention, and we're emitting precise
+ // SP-based CFI, emit a CFA adjust for the amount the callee popped.
+ if (isDestroy && InternalAmt && DwarfCFI && !hasFP(MF) &&
+ MMI.usePreciseUnwindInfo())
+ 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 (!(MF.getFunction()->optForMinSize() &&
+ 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;
+ if (!MMI.usePreciseUnwindInfo())
+ CFAOffset += InternalAmt;
+ CFAOffset = isDestroy ? -CFAOffset : CFAOffset;
+ BuildCFI(MBB, I, DL,
+ MCCFIInstruction::createAdjustCfaOffset(nullptr, CFAOffset));
+ }
+
return;
}
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 (MBB.getParent()->getSubtarget<X86Subtarget>().isTargetWin64() &&
+ !MBB.succ_empty() && !MBB.isReturnBlock())
+ return false;
+
if (canUseLEAForSPInEpilogue(*MBB.getParent()))
return true;
return !terminatorsNeedFlagsAsInput(MBB);
}
-MachineBasicBlock::iterator X86FrameLowering::restoreWin32EHFrameAndBasePtr(
+MachineBasicBlock::iterator X86FrameLowering::restoreWin32EHStackPointers(
MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
- DebugLoc DL) const {
+ 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 &&
// 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 EHRegSize = MFI->getObjectSize(FI);
int EndOffset = -EHRegOffset - EHRegSize;
- assert(EndOffset >= 0 &&
- "end of registration object above normal EBP position!");
+ FuncInfo.EHRegNodeEndOffset = EndOffset;
+
if (UsedReg == FramePtr) {
// ADD $offset, %ebp
- assert(UsedReg == FramePtr);
unsigned ADDri = getADDriOpcode(false, EndOffset);
BuildMI(MBB, MBBI, DL, TII.get(ADDri), FramePtr)
.addReg(FramePtr)
.setMIFlag(MachineInstr::FrameSetup)
->getOperand(3)
.setIsDead();
- } else {
- assert(UsedReg == BasePtr);
+ 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);
- // MOV32mr SavedEBPOffset(%esi), %ebp
+ // 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::MOV32mr)), UsedReg, true,
- Offset)
- .addReg(FramePtr)
+ 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;
+}
projects / oota-llvm.git / blobdiff