Index: llvm/lib/Target/ARM/ARMFrameLowering.cpp
===================================================================
--- llvm/lib/Target/ARM/ARMFrameLowering.cpp
+++ llvm/lib/Target/ARM/ARMFrameLowering.cpp
@@ -579,18 +579,6 @@
return count;
}
-static bool WindowsRequiresStackProbe(const MachineFunction &MF,
- size_t StackSizeInBytes) {
- const MachineFrameInfo &MFI = MF.getFrameInfo();
- const Function &F = MF.getFunction();
- unsigned StackProbeSize = (MFI.getStackProtectorIndex() > 0) ? 4080 : 4096;
-
- StackProbeSize =
- F.getFnAttributeAsParsedInteger("stack-probe-size", StackProbeSize);
- return (StackSizeInBytes >= StackProbeSize) &&
- !F.hasFnAttribute("no-stack-arg-probe");
-}
-
namespace {
struct StackAdjustingInsts {
@@ -749,6 +737,10 @@
int FPCXTSaveSize = 0;
bool NeedsWinCFI = needsWinCFI(MF);
+ const bool EmitStackProbeCall =
+ STI.getTargetLowering()->hasStackProbeSymbol(MF);
+ unsigned StackProbeSize = STI.getTargetLowering()->getStackProbeSize(MF);
+
// Debug location must be unknown since the first debug location is used
// to determine the end of the prologue.
DebugLoc dl;
@@ -770,7 +762,7 @@
bool HasFP = hasFP(MF);
if (!AFI->hasStackFrame() &&
- (!STI.isTargetWindows() || !WindowsRequiresStackProbe(MF, NumBytes))) {
+ !(EmitStackProbeCall && NumBytes >= StackProbeSize)) {
if (NumBytes != 0) {
emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes,
MachineInstr::FrameSetup);
@@ -972,7 +964,7 @@
if (STI.splitFramePointerPush(MF) && HasFP)
NeedsWinCFIStackAlloc = false;
- if (STI.isTargetWindows() && WindowsRequiresStackProbe(MF, NumBytes)) {
+ if (NumBytes >= StackProbeSize && EmitStackProbeCall) {
uint32_t NumWords = NumBytes >> 2;
if (NumWords < 65536) {
@@ -995,6 +987,8 @@
.add(predOps(ARMCC::AL));
}
+ StringRef Symbol = STI.getTargetLowering()->getStackProbeSymbolName(MF);
+
switch (TM.getCodeModel()) {
case CodeModel::Tiny:
llvm_unreachable("Tiny code model not available on ARM.");
@@ -1003,14 +997,14 @@
case CodeModel::Kernel:
BuildMI(MBB, MBBI, dl, TII.get(ARM::tBL))
.add(predOps(ARMCC::AL))
- .addExternalSymbol("__chkstk")
+ .addExternalSymbol(MF.createExternalSymbolName(Symbol))
.addReg(ARM::R4, RegState::Implicit)
.setMIFlags(MachineInstr::FrameSetup);
break;
case CodeModel::Large:
BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi32imm), ARM::R12)
- .addExternalSymbol("__chkstk")
- .setMIFlags(MachineInstr::FrameSetup);
+ .addExternalSymbol(MF.createExternalSymbolName(Symbol))
+ .setMIFlags(MachineInstr::FrameSetup);
BuildMI(MBB, MBBI, dl, TII.get(ARM::tBLXr))
.add(predOps(ARMCC::AL))
@@ -2286,6 +2280,10 @@
(void)TRI; // Silence unused warning in non-assert builds.
Register FramePtr = RegInfo->getFrameRegister(MF);
+ const bool EmitStackProbeCall =
+ STI.getTargetLowering()->hasStackProbeSymbol(MF);
+ unsigned StackProbeSize = STI.getTargetLowering()->getStackProbeSize(MF);
+
// Spill R4 if Thumb2 function requires stack realignment - it will be used as
// scratch register. Also spill R4 if Thumb2 function has varsized objects,
// since it's not always possible to restore sp from fp in a single
@@ -2300,8 +2298,7 @@
// This estimate should be a safe, conservative estimate. The actual
// stack probe is enabled based on the size of the local objects;
// this estimate also includes the varargs store size.
- if (STI.isTargetWindows() &&
- WindowsRequiresStackProbe(MF, MFI.estimateStackSize(MF))) {
+ if (MFI.estimateStackSize(MF) >= StackProbeSize && EmitStackProbeCall) {
SavedRegs.set(ARM::R4);
SavedRegs.set(ARM::LR);
}
Index: llvm/lib/Target/ARM/ARMISelLowering.h
===================================================================
--- llvm/lib/Target/ARM/ARMISelLowering.h
+++ llvm/lib/Target/ARM/ARMISelLowering.h
@@ -696,6 +696,10 @@
return true;
}
+ bool hasStackProbeSymbol(const MachineFunction &MF) const override;
+ StringRef getStackProbeSymbolName(const MachineFunction &MF) const override;
+ unsigned getStackProbeSize(const MachineFunction &MF) const;
+
bool hasStandaloneRem(EVT VT) const override {
return HasStandaloneRem;
}
Index: llvm/lib/Target/ARM/ARMISelLowering.cpp
===================================================================
--- llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -22129,3 +22129,43 @@
return nullptr;
}
+
+/// Returns true if stack probing through a function call is requested.
+bool ARMTargetLowering::hasStackProbeSymbol(const MachineFunction &MF) const {
+ return !getStackProbeSymbolName(MF).empty();
+}
+
+/// Returns the name of the symbol used to emit stack probes or the empty
+/// string if not applicable.
+StringRef
+ARMTargetLowering::getStackProbeSymbolName(const MachineFunction &MF) const {
+ // If the function specifically requests stack probes, emit them.
+ if (MF.getFunction().hasFnAttribute("probe-stack"))
+ return MF.getFunction().getFnAttribute("probe-stack").getValueAsString();
+
+ if (Subtarget->isTargetWindows() &&
+ !MF.getFunction().hasFnAttribute("no-stack-arg-probe"))
+ return "__chkstk";
+
+ // Generally, if we aren't on Windows, the platform ABI does not include
+ // support for stack probes, so don't emit them.
+ return "";
+}
+
+unsigned ARMTargetLowering::getStackProbeSize(const MachineFunction &MF) const {
+ // The default stack probe size is 4096 if the function has no stackprobesize
+ // attribute.
+ const MachineFrameInfo &MFI = MF.getFrameInfo();
+
+ unsigned StackProbeSize = 4096;
+
+ if (Subtarget->isTargetWindows())
+ StackProbeSize = (MFI.getStackProtectorIndex() > 0) ? 4080 : 4096;
+
+ const Function &Fn = MF.getFunction();
+ if (Fn.hasFnAttribute("stack-probe-size"))
+ Fn.getFnAttribute("stack-probe-size")
+ .getValueAsString()
+ .getAsInteger(0, StackProbeSize);
+ return StackProbeSize;
+}
Index: llvm/test/CodeGen/ARM/stack-probe-size.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/ARM/stack-probe-size.ll
@@ -0,0 +1,42 @@
+; This tests that the probe-stack attribute properly calls the probe-stack
+; function.
+;
+; RUN: llc < %s -mtriple=arm-none | FileCheck %s
+
+define void @_test1() "probe-stack"="__probestack" "stack-probe-size"="0" {
+ %array = alloca [1024 x i8], align 16
+ ret void
+
+; CHECK-LABEL: test1:
+; CHECK: movw r4, #256
+; CHECK-NEXT: bl __probestack
+; CHECK-NEXT: sub.w sp, sp, r4
+}
+
+define void @_test2() "probe-stack"="__probestack" "stack-probe-size"="1024" {
+ %array = alloca [1024 x i8], align 16
+ ret void
+
+; CHECK-LABEL: test2:
+; CHECK: movw r4, #256
+; CHECK-NEXT: bl __probestack
+; CHECK-NEXT: sub.w sp, sp, r4
+}
+
+define void @_test3() "probe-stack"="__probestack" "stack-probe-size"="8192" {
+ %array = alloca [8192 x i8], align 16
+ ret void
+
+; CHECK-LABEL: test3:
+; CHECK: movw r4, #2048
+; CHECK-NEXT: bl __probestack
+; CHECK-NEXT: sub.w sp, sp, r4
+}
+
+define void @_test4() "probe-stack"="__probestack" "stack-probe-size"="8192" {
+ %array = alloca [4096 x i8], align 16
+ ret void
+
+; CHECK-LABEL: test4:
+; CHECK-NOT: bl __probestack
+}
Index: llvm/test/CodeGen/ARM/stack-probe.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/ARM/stack-probe.ll
@@ -0,0 +1,14 @@
+; This tests that the probe-stack attribute properly calls the probe-stack
+; function.
+;
+; RUN: llc < %s -mtriple=arm-none | FileCheck %s
+
+define void @_test1() "probe-stack"="__probestack" {
+ %array = alloca [4096 x i8], align 16
+ ret void
+
+; CHECK-LABEL: test1:
+; CHECK: movw r4, #1024
+; CHECK-NEXT: bl __probestack
+; CHECK-NEXT: sub.w sp, sp, r4
+}