Index: include/llvm/CodeGen/WinEHFuncInfo.h
===================================================================
--- include/llvm/CodeGen/WinEHFuncInfo.h
+++ include/llvm/CodeGen/WinEHFuncInfo.h
@@ -96,6 +96,7 @@
SmallVector<SEHUnwindMapEntry, 4> SEHUnwindMap;
SmallVector<ClrEHUnwindMapEntry, 4> ClrEHUnwindMap;
int UnwindHelpFrameIdx = INT_MAX;
+ int PSPSymFrameIdx = INT_MAX;
int getLastStateNumber() const { return CxxUnwindMap.size() - 1; }
Index: lib/Target/X86/X86FrameLowering.h
===================================================================
--- lib/Target/X86/X86FrameLowering.h
+++ lib/Target/X86/X86FrameLowering.h
@@ -187,6 +187,8 @@
DebugLoc DL, int64_t Offset,
bool InEpilogue) const;
+ unsigned getPSPSlotOffsetFromSP(const MachineFunction &MF) const;
+
unsigned getWinEHFuncletFrameSize(const MachineFunction &MF) const;
};
Index: lib/Target/X86/X86FrameLowering.cpp
===================================================================
--- lib/Target/X86/X86FrameLowering.cpp
+++ lib/Target/X86/X86FrameLowering.cpp
@@ -900,9 +900,10 @@
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 &&
+ bool FnHasClrFunclet =
+ MMI.hasEHFunclets() &&
classifyEHPersonality(Fn->getPersonalityFn()) == EHPersonality::CoreCLR;
+ bool IsClrFunclet = IsFunclet && FnHasClrFunclet;
bool HasFP = hasFP(MF);
bool IsWin64CC = STI.isCallingConvWin64(Fn->getCallingConv());
bool IsWin64Prologue = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
@@ -1194,7 +1195,28 @@
.setMIFlag(MachineInstr::FrameSetup);
int SEHFrameOffset = 0;
- unsigned SPOrEstablisher = IsFunclet ? Establisher : StackPtr;
+ 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);
+ addRegOffset(
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64rm)).addReg(Establisher),
+ Establisher, false, PSPSlotOffset);
+ // 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);
+ }
+ SPOrEstablisher = Establisher;
+ } else {
+ SPOrEstablisher = StackPtr;
+ }
+
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
@@ -1243,6 +1265,16 @@
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);
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64mr)), StackPtr, false,
+ PSPSlotOffset)
+ .addReg(StackPtr);
+ }
+
// 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.
@@ -1328,17 +1360,54 @@
llvm_unreachable("impossible");
}
-unsigned X86FrameLowering::getWinEHFuncletFrameSize(const MachineFunction &MF) const {
+// 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 {
+ MachineModuleInfo &MMI = MF.getMMI();
+ WinEHFuncInfo &Info = MMI.getWinEHFuncInfo(MF.getFunction());
+ // 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 MaxCallSize = MF.getFrameInfo()->getMaxCallFrameSize();
+ 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 + MaxCallSize, getStackAlignment());
+ 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;
Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -2878,18 +2878,34 @@
FuncInfo->setArgumentStackSize(StackSize);
- if (MMI.hasWinEHFuncInfo(Fn) && Is64Bit &&
- classifyEHPersonality(Fn->getPersonalityFn()) ==
- EHPersonality::MSVC_CXX) {
- int UnwindHelpFI = MFI->CreateStackObject(8, 8, /*isSS=*/false);
- SDValue StackSlot = DAG.getFrameIndex(UnwindHelpFI, MVT::i64);
- MMI.getWinEHFuncInfo(MF.getFunction()).UnwindHelpFrameIdx = UnwindHelpFI;
- SDValue Neg2 = DAG.getConstant(-2, dl, MVT::i64);
- Chain = DAG.getStore(Chain, dl, Neg2, StackSlot,
- MachinePointerInfo::getFixedStack(
- DAG.getMachineFunction(), UnwindHelpFI),
- /*isVolatile=*/true,
- /*isNonTemporal=*/false, /*Alignment=*/0);
+ if (MMI.hasWinEHFuncInfo(Fn)) {
+ EHPersonality Personality = classifyEHPersonality(Fn->getPersonalityFn());
+ if (Personality == EHPersonality::MSVC_CXX) {
+ if (Is64Bit) {
+ int UnwindHelpFI = MFI->CreateStackObject(8, 8, /*isSS=*/false);
+ SDValue StackSlot = DAG.getFrameIndex(UnwindHelpFI, MVT::i64);
+ MMI.getWinEHFuncInfo(MF.getFunction()).UnwindHelpFrameIdx =
+ UnwindHelpFI;
+ SDValue Neg2 = DAG.getConstant(-2, dl, MVT::i64);
+ Chain = DAG.getStore(Chain, dl, Neg2, StackSlot,
+ MachinePointerInfo::getFixedStack(
+ DAG.getMachineFunction(), UnwindHelpFI),
+ /*isVolatile=*/true,
+ /*isNonTemporal=*/false, /*Alignment=*/0);
+ }
+ } else if (Personality == EHPersonality::CoreCLR) {
+ assert(Is64Bit);
+ // TODO: Add a mechanism to frame lowering that will allow us to indicate
+ // that we'd prefer this slot be allocated towards the bottom of the frame
+ // (i.e. near the stack pointer after allocating the frame). Every
+ // funclet needs a copy of this slot in its (mostly empty) frame, and the
+ // offset from the bottom of this and each funclet's frame must be the
+ // same, so the size of funclets' (mostly empty) frames is dictated by
+ // how far this slot is from the bottom (since they allocate just enough
+ // space to accomodate holding this slot at the correct offset).
+ int PSPSymFI = MFI->CreateStackObject(8, 8, /*isSS=*/false);
+ MMI.getWinEHFuncInfo(MF.getFunction()).PSPSymFrameIdx = PSPSymFI;
+ }
}
return Chain;
Index: test/CodeGen/WinEH/wineh-coreclr.ll
===================================================================
--- test/CodeGen/WinEH/wineh-coreclr.ll
+++ test/CodeGen/WinEH/wineh-coreclr.ll
@@ -32,7 +32,9 @@
define void @test1() personality i8* bitcast (void ()* @ProcessCLRException to i8*) {
entry:
; CHECK: # %entry
+; CHECK: leaq [[FPOffset:[0-9]+]](%rsp), %rbp
; CHECK: .seh_endprologue
+; CHECK: movq %rsp, [[PSPSymOffset:[0-9]+]](%rsp)
; CHECK: [[L_before_f1:.+]]:
; CHECK-NEXT: movl $1, %ecx
; CHECK-NEXT: callq f
@@ -52,8 +54,12 @@
%catch1 = catchpad [i32 1]
to label %catch1.body unwind label %catch2.pad
catch1.body:
-; CHECK: leaq {{[0-9]+}}(%rcx), %rbp
-; ^ establisher frame pointer passed in rcx
+; CHECK: .seh_stackalloc [[FuncletFrameSize:[0-9]+]]
+; ^ all funclets use the same frame size
+; CHECK: movq [[PSPSymOffset]](%rcx), %rcx
+; ^ establisher frame pointer passed in rcx
+; CHECK: movq %rcx, [[PSPSymOffset]](%rsp)
+; CHECK: leaq [[FPOffset]](%rcx), %rbp
; CHECK: .seh_endprologue
; CHECK: movq %rdx, %rcx
; ^ exception pointer passed in rdx
@@ -73,8 +79,12 @@
%catch2 = catchpad [i32 2]
to label %catch2.body unwind label %catch.end
catch2.body:
-; CHECK: leaq {{[0-9]+}}(%rcx), %rbp
-; ^ establisher frame pointer passed in rcx
+; CHECK: .seh_stackalloc [[FuncletFrameSize:[0-9]+]]
+; ^ all funclets use the same frame size
+; CHECK: movq [[PSPSymOffset]](%rcx), %rcx
+; ^ establisher frame pointer passed in rcx
+; CHECK: movq %rcx, [[PSPSymOffset]](%rsp)
+; CHECK: leaq [[FPOffset]](%rcx), %rbp
; CHECK: .seh_endprologue
; CHECK: movq %rdx, %rcx
; ^ exception pointer passed in rdx
@@ -98,8 +108,12 @@
fault.pad:
; CHECK: .seh_proc [[L_fault:[^ ]+]]
%fault = cleanuppad [i32 undef]
-; CHECK: leaq {{[0-9]+}}(%rcx), %rbp
-; ^ establisher frame pointer passed in rcx
+; CHECK: .seh_stackalloc [[FuncletFrameSize:[0-9]+]]
+; ^ all funclets use the same frame size
+; CHECK: movq [[PSPSymOffset]](%rcx), %rcx
+; ^ establisher frame pointer passed in rcx
+; CHECK: movq %rcx, [[PSPSymOffset]](%rsp)
+; CHECK: leaq [[FPOffset]](%rcx), %rbp
; CHECK: .seh_endprologue
; CHECK: [[L_before_f6:.+]]:
; CHECK-NEXT: movl $6, %ecx
@@ -121,8 +135,12 @@
finally.pad:
; CHECK: .seh_proc [[L_finally:[^ ]+]]
%finally = cleanuppad []
-; CHECK: leaq {{[0-9]+}}(%rcx), %rbp
-; ^ establisher frame pointer passed in rcx
+; CHECK: .seh_stackalloc [[FuncletFrameSize:[0-9]+]]
+; ^ all funclets use the same frame size
+; CHECK: movq [[PSPSymOffset]](%rcx), %rcx
+; ^ establisher frame pointer passed in rcx
+; CHECK: movq %rcx, [[PSPSymOffset]](%rsp)
+; CHECK: leaq [[FPOffset]](%rcx), %rbp
; CHECK: .seh_endprologue
; CHECK: [[L_before_f7:.+]]:
; CHECK-NEXT: movl $7, %ecx