[llvm] r360479 - Factor out redzone ABI checks [NFCI]
Philip Reames via llvm-commits
llvm-commits at lists.llvm.org
Fri May 10 15:55:42 PDT 2019
Author: reames
Date: Fri May 10 15:55:42 2019
New Revision: 360479
URL: http://llvm.org/viewvc/llvm-project?rev=360479&view=rev
Log:
Factor out redzone ABI checks [NFCI]
As requested in D58632, cleanup our red zone detection logic in the X86 backend. The existing X86MachineFunctionInfo flag is used to track whether we *use* the redzone (via a particularly optimization?), but there's no common way to check whether the function *has* a red zone.
I'd appreciate careful review of the uses being updated. I think they are NFC, but a careful eye from someone else would be appreciated.
Differential Revision: https://reviews.llvm.org/D61799
Modified:
llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
llvm/trunk/lib/Target/X86/X86FrameLowering.h
llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
llvm/trunk/lib/Target/X86/X86SpeculativeLoadHardening.cpp
Modified: llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FrameLowering.cpp?rev=360479&r1=360478&r2=360479&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86FrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86FrameLowering.cpp Fri May 10 15:55:42 2019
@@ -872,6 +872,17 @@ void X86FrameLowering::BuildStackAlignAN
MI->getOperand(3).setIsDead();
}
+bool X86FrameLowering::has128ByteRedZone(const MachineFunction& MF) const {
+ // x86-64 (non Win64) has a 128 byte red zone which is guaranteed not to be
+ // clobbered by any interrupt handler.
+ assert(&STI == &MF.getSubtarget<X86Subtarget>() &&
+ "MF used frame lowering for wrong subtarget");
+ const Function &Fn = MF.getFunction();
+ const bool IsWin64CC = STI.isCallingConvWin64(Fn.getCallingConv());
+ return Is64Bit && !IsWin64CC && !Fn.hasFnAttribute(Attribute::NoRedZone);
+}
+
+
/// 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
@@ -976,7 +987,6 @@ void X86FrameLowering::emitPrologue(Mach
MF.hasEHFunclets() && Personality == EHPersonality::CoreCLR;
bool IsClrFunclet = IsFunclet && FnHasClrFunclet;
bool HasFP = hasFP(MF);
- bool IsWin64CC = STI.isCallingConvWin64(Fn.getCallingConv());
bool IsWin64Prologue = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
bool NeedsWin64CFI = IsWin64Prologue && Fn.needsUnwindTableEntry();
// FIXME: Emit FPO data for EH funclets.
@@ -1030,12 +1040,11 @@ void X86FrameLowering::emitPrologue(Mach
// 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.hasFnAttribute(Attribute::NoRedZone) &&
+ if (has128ByteRedZone(MF) &&
!TRI->needsStackRealignment(MF) &&
!MFI.hasVarSizedObjects() && // No dynamic alloca.
!MFI.adjustsStack() && // No calls.
!UseStackProbe && // No stack probes.
- !IsWin64CC && // Win64 has no Red Zone
!MFI.hasCopyImplyingStackAdjustment() && // Don't push and pop.
!MF.shouldSplitStack()) { // Regular stack
uint64_t MinSize = X86FI->getCalleeSavedFrameSize();
Modified: llvm/trunk/lib/Target/X86/X86FrameLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FrameLowering.h?rev=360479&r1=360478&r2=360479&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86FrameLowering.h (original)
+++ llvm/trunk/lib/Target/X86/X86FrameLowering.h Fri May 10 15:55:42 2019
@@ -171,6 +171,10 @@ public:
unsigned getInitialCFARegister(const MachineFunction &MF) const override;
+ /// Return true if the function has a redzone (accessible bytes past the
+ /// frame of the top of stack function) as part of it's ABI.
+ bool has128ByteRedZone(const MachineFunction& MF) const;
+
private:
uint64_t calculateMaxStackAlign(const MachineFunction &MF) const;
Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.cpp?rev=360479&r1=360478&r2=360479&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.cpp Fri May 10 15:55:42 2019
@@ -7464,7 +7464,7 @@ bool X86InstrInfo::isFunctionSafeToOutli
// Does the function use a red zone? If it does, then we can't risk messing
// with the stack.
- if (!F.hasFnAttribute(Attribute::NoRedZone)) {
+ if (Subtarget.getFrameLowering()->has128ByteRedZone(MF)) {
// It could have a red zone. If it does, then we don't want to touch it.
const X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
if (!X86FI || X86FI->getUsesRedZone())
Modified: llvm/trunk/lib/Target/X86/X86SpeculativeLoadHardening.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86SpeculativeLoadHardening.cpp?rev=360479&r1=360478&r2=360479&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86SpeculativeLoadHardening.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86SpeculativeLoadHardening.cpp Fri May 10 15:55:42 2019
@@ -2473,7 +2473,7 @@ void X86SpeculativeLoadHardeningPass::tr
// If we have no red zones or if the function returns twice (possibly without
// using the `ret` instruction) like setjmp, we need to save the expected
// return address prior to the call.
- if (MF.getFunction().hasFnAttribute(Attribute::NoRedZone) ||
+ if (!Subtarget->getFrameLowering()->has128ByteRedZone(MF) ||
MF.exposesReturnsTwice()) {
// If we don't have red zones, we need to compute the expected return
// address prior to the call and store it in a register that lives across
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