[llvm] f2c6bfa - Fix interaction between stack alignment and inline-asm stack clash protection
via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 2 07:52:04 PDT 2020
Author: serge-sans-paille
Date: 2020-10-02T16:51:49+02:00
New Revision: f2c6bfa350de142e4d63808d03335f69bd136d6a
URL: https://github.com/llvm/llvm-project/commit/f2c6bfa350de142e4d63808d03335f69bd136d6a
DIFF: https://github.com/llvm/llvm-project/commit/f2c6bfa350de142e4d63808d03335f69bd136d6a.diff
LOG: Fix interaction between stack alignment and inline-asm stack clash protection
As reported in https://github.com/rust-lang/rust/issues/70143 alignment is not
taken into account when doing the probing. Fix that by adjusting the first probe
if the stack align is small, or by extending the dynamic probing if the
alignment is large.
Differential Revision: https://reviews.llvm.org/D84419
Added:
llvm/test/CodeGen/X86/stack-clash-large-large-align.ll
llvm/test/CodeGen/X86/stack-clash-small-alloc-medium-align.ll
llvm/test/CodeGen/X86/stack-clash-small-large-align.ll
Modified:
llvm/lib/Target/X86/X86FrameLowering.cpp
llvm/lib/Target/X86/X86FrameLowering.h
Removed:
llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
################################################################################
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
index 90265ddf344a..6d196a622837 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -586,29 +586,55 @@ void X86FrameLowering::emitStackProbeInlineGeneric(
const uint64_t StackProbeSize = TLI.getStackProbeSize(MF);
uint64_t ProbeChunk = StackProbeSize * 8;
+ uint64_t MaxAlign =
+ TRI->needsStackRealignment(MF) ? calculateMaxStackAlign(MF) : 0;
+
// Synthesize a loop or unroll it, depending on the number of iterations.
+ // BuildStackAlignAND ensures that only MaxAlign % StackProbeSize bits left
+ // between the unaligned rsp and current rsp.
if (Offset > ProbeChunk) {
- emitStackProbeInlineGenericLoop(MF, MBB, MBBI, DL, Offset);
+ emitStackProbeInlineGenericLoop(MF, MBB, MBBI, DL, Offset,
+ MaxAlign % StackProbeSize);
} else {
- emitStackProbeInlineGenericBlock(MF, MBB, MBBI, DL, Offset);
+ emitStackProbeInlineGenericBlock(MF, MBB, MBBI, DL, Offset,
+ MaxAlign % StackProbeSize);
}
}
void X86FrameLowering::emitStackProbeInlineGenericBlock(
MachineFunction &MF, MachineBasicBlock &MBB,
- MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
- uint64_t Offset) const {
+ MachineBasicBlock::iterator MBBI, const DebugLoc &DL, uint64_t Offset,
+ uint64_t AlignOffset) const {
const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
const X86TargetLowering &TLI = *STI.getTargetLowering();
const unsigned Opc = getSUBriOpcode(Uses64BitFramePtr, Offset);
const unsigned MovMIOpc = Is64Bit ? X86::MOV64mi32 : X86::MOV32mi;
const uint64_t StackProbeSize = TLI.getStackProbeSize(MF);
+
uint64_t CurrentOffset = 0;
- // 0 Thanks to return address being saved on the stack
- uint64_t CurrentProbeOffset = 0;
- // For the first N - 1 pages, just probe. I tried to take advantage of
+ assert(AlignOffset < StackProbeSize);
+
+ // If the offset is so small it fits within a page, there's nothing to do.
+ if (StackProbeSize < Offset + AlignOffset) {
+
+ MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr)
+ .addReg(StackPtr)
+ .addImm(StackProbeSize - AlignOffset)
+ .setMIFlag(MachineInstr::FrameSetup);
+ MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
+
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(MovMIOpc))
+ .setMIFlag(MachineInstr::FrameSetup),
+ StackPtr, false, 0)
+ .addImm(0)
+ .setMIFlag(MachineInstr::FrameSetup);
+ NumFrameExtraProbe++;
+ CurrentOffset = StackProbeSize - AlignOffset;
+ }
+
+ // For the next N - 1 pages, just probe. I tried to take advantage of
// natural probes but it implies much more logic and there was very few
// interesting natural probes to interleave.
while (CurrentOffset + StackProbeSize < Offset) {
@@ -626,9 +652,9 @@ void X86FrameLowering::emitStackProbeInlineGenericBlock(
.setMIFlag(MachineInstr::FrameSetup);
NumFrameExtraProbe++;
CurrentOffset += StackProbeSize;
- CurrentProbeOffset += StackProbeSize;
}
+ // No need to probe the tail, it is smaller than a Page.
uint64_t ChunkSize = Offset - CurrentOffset;
MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr)
.addReg(StackPtr)
@@ -639,8 +665,8 @@ void X86FrameLowering::emitStackProbeInlineGenericBlock(
void X86FrameLowering::emitStackProbeInlineGenericLoop(
MachineFunction &MF, MachineBasicBlock &MBB,
- MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
- uint64_t Offset) const {
+ MachineBasicBlock::iterator MBBI, const DebugLoc &DL, uint64_t Offset,
+ uint64_t AlignOffset) const {
assert(Offset && "null offset");
const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
@@ -648,6 +674,26 @@ void X86FrameLowering::emitStackProbeInlineGenericLoop(
const unsigned MovMIOpc = Is64Bit ? X86::MOV64mi32 : X86::MOV32mi;
const uint64_t StackProbeSize = TLI.getStackProbeSize(MF);
+ if (AlignOffset) {
+ if (AlignOffset < StackProbeSize) {
+ // Perform a first smaller allocation followed by a probe.
+ const unsigned SUBOpc = getSUBriOpcode(Uses64BitFramePtr, AlignOffset);
+ MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(SUBOpc), StackPtr)
+ .addReg(StackPtr)
+ .addImm(AlignOffset)
+ .setMIFlag(MachineInstr::FrameSetup);
+ MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
+
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(MovMIOpc))
+ .setMIFlag(MachineInstr::FrameSetup),
+ StackPtr, false, 0)
+ .addImm(0)
+ .setMIFlag(MachineInstr::FrameSetup);
+ NumFrameExtraProbe++;
+ Offset -= AlignOffset;
+ }
+ }
+
// Synthesize a loop
NumFrameLoopProbe++;
const BasicBlock *LLVM_BB = MBB.getBasicBlock();
@@ -666,8 +712,8 @@ void X86FrameLowering::emitStackProbeInlineGenericLoop(
// save loop bound
{
- const unsigned Opc = getSUBriOpcode(Uses64BitFramePtr, Offset);
- BuildMI(MBB, MBBI, DL, TII.get(Opc), FinalStackProbed)
+ const unsigned SUBOpc = getSUBriOpcode(Uses64BitFramePtr, Offset);
+ BuildMI(MBB, MBBI, DL, TII.get(SUBOpc), FinalStackProbed)
.addReg(FinalStackProbed)
.addImm(Offset / StackProbeSize * StackProbeSize)
.setMIFlag(MachineInstr::FrameSetup);
@@ -675,8 +721,8 @@ void X86FrameLowering::emitStackProbeInlineGenericLoop(
// allocate a page
{
- const unsigned Opc = getSUBriOpcode(Uses64BitFramePtr, StackProbeSize);
- BuildMI(testMBB, DL, TII.get(Opc), StackPtr)
+ const unsigned SUBOpc = getSUBriOpcode(Uses64BitFramePtr, StackProbeSize);
+ BuildMI(testMBB, DL, TII.get(SUBOpc), StackPtr)
.addReg(StackPtr)
.addImm(StackProbeSize)
.setMIFlag(MachineInstr::FrameSetup);
@@ -1052,13 +1098,149 @@ void X86FrameLowering::BuildStackAlignAND(MachineBasicBlock &MBB,
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();
+ MachineFunction &MF = *MBB.getParent();
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ const X86TargetLowering &TLI = *STI.getTargetLowering();
+ const uint64_t StackProbeSize = TLI.getStackProbeSize(MF);
+ const bool EmitInlineStackProbe = TLI.hasInlineStackProbe(MF);
+
+ // We want to make sure that (in worst case) less than StackProbeSize bytes
+ // are not probed after the AND. This assumption is used in
+ // emitStackProbeInlineGeneric.
+ if (Reg == StackPtr && EmitInlineStackProbe && MaxAlign >= StackProbeSize) {
+ {
+ NumFrameLoopProbe++;
+ MachineBasicBlock *entryMBB =
+ MF.CreateMachineBasicBlock(MBB.getBasicBlock());
+ MachineBasicBlock *headMBB =
+ MF.CreateMachineBasicBlock(MBB.getBasicBlock());
+ MachineBasicBlock *bodyMBB =
+ MF.CreateMachineBasicBlock(MBB.getBasicBlock());
+ MachineBasicBlock *footMBB =
+ MF.CreateMachineBasicBlock(MBB.getBasicBlock());
+
+ MachineFunction::iterator MBBIter = MBB.getIterator();
+ MF.insert(MBBIter, entryMBB);
+ MF.insert(MBBIter, headMBB);
+ MF.insert(MBBIter, bodyMBB);
+ MF.insert(MBBIter, footMBB);
+ const unsigned MovMIOpc = Is64Bit ? X86::MOV64mi32 : X86::MOV32mi;
+ Register FinalStackProbed = Uses64BitFramePtr ? X86::R11 : X86::R11D;
+
+ // Setup entry block
+ {
+
+ entryMBB->splice(entryMBB->end(), &MBB, MBB.begin(), MBBI);
+ BuildMI(entryMBB, DL, TII.get(TargetOpcode::COPY), FinalStackProbed)
+ .addReg(StackPtr)
+ .setMIFlag(MachineInstr::FrameSetup);
+ MachineInstr *MI =
+ BuildMI(entryMBB, DL, TII.get(AndOp), FinalStackProbed)
+ .addReg(FinalStackProbed)
+ .addImm(Val)
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ // The EFLAGS implicit def is dead.
+ MI->getOperand(3).setIsDead();
+
+ BuildMI(entryMBB, DL,
+ TII.get(Uses64BitFramePtr ? X86::CMP64rr : X86::CMP32rr))
+ .addReg(FinalStackProbed)
+ .addReg(StackPtr)
+ .setMIFlag(MachineInstr::FrameSetup);
+ BuildMI(entryMBB, DL, TII.get(X86::JCC_1))
+ .addMBB(&MBB)
+ .addImm(X86::COND_E)
+ .setMIFlag(MachineInstr::FrameSetup);
+ entryMBB->addSuccessor(headMBB);
+ entryMBB->addSuccessor(&MBB);
+ }
+
+ // Loop entry block
+
+ {
+ const unsigned SUBOpc =
+ getSUBriOpcode(Uses64BitFramePtr, StackProbeSize);
+ BuildMI(headMBB, DL, TII.get(SUBOpc), StackPtr)
+ .addReg(StackPtr)
+ .addImm(StackProbeSize)
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ BuildMI(headMBB, DL,
+ TII.get(Uses64BitFramePtr ? X86::CMP64rr : X86::CMP32rr))
+ .addReg(FinalStackProbed)
+ .addReg(StackPtr)
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ // jump
+ BuildMI(headMBB, DL, TII.get(X86::JCC_1))
+ .addMBB(footMBB)
+ .addImm(X86::COND_B)
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ headMBB->addSuccessor(bodyMBB);
+ headMBB->addSuccessor(footMBB);
+ }
+
+ // setup loop body
+ {
+ addRegOffset(BuildMI(bodyMBB, DL, TII.get(MovMIOpc))
+ .setMIFlag(MachineInstr::FrameSetup),
+ StackPtr, false, 0)
+ .addImm(0)
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ const unsigned SUBOpc =
+ getSUBriOpcode(Uses64BitFramePtr, StackProbeSize);
+ BuildMI(bodyMBB, DL, TII.get(SUBOpc), StackPtr)
+ .addReg(StackPtr)
+ .addImm(StackProbeSize)
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ // cmp with stack pointer bound
+ BuildMI(bodyMBB, DL,
+ TII.get(Uses64BitFramePtr ? X86::CMP64rr : X86::CMP32rr))
+ .addReg(FinalStackProbed)
+ .addReg(StackPtr)
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ // jump
+ BuildMI(bodyMBB, DL, TII.get(X86::JCC_1))
+ .addMBB(bodyMBB)
+ .addImm(X86::COND_B)
+ .setMIFlag(MachineInstr::FrameSetup);
+ bodyMBB->addSuccessor(bodyMBB);
+ bodyMBB->addSuccessor(footMBB);
+ }
+
+ // setup loop footer
+ {
+ BuildMI(footMBB, DL, TII.get(TargetOpcode::COPY), StackPtr)
+ .addReg(FinalStackProbed)
+ .setMIFlag(MachineInstr::FrameSetup);
+ addRegOffset(BuildMI(footMBB, DL, TII.get(MovMIOpc))
+ .setMIFlag(MachineInstr::FrameSetup),
+ StackPtr, false, 0)
+ .addImm(0)
+ .setMIFlag(MachineInstr::FrameSetup);
+ footMBB->addSuccessor(&MBB);
+ }
+
+ recomputeLiveIns(*headMBB);
+ recomputeLiveIns(*bodyMBB);
+ recomputeLiveIns(*footMBB);
+ recomputeLiveIns(MBB);
+ }
+ } else {
+ 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();
+ }
}
bool X86FrameLowering::has128ByteRedZone(const MachineFunction& MF) const {
diff --git a/llvm/lib/Target/X86/X86FrameLowering.h b/llvm/lib/Target/X86/X86FrameLowering.h
index c0b4be95f88d..bb2e83205e71 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.h
+++ b/llvm/lib/Target/X86/X86FrameLowering.h
@@ -213,14 +213,14 @@ class X86FrameLowering : public TargetFrameLowering {
void emitStackProbeInlineGenericBlock(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
- const DebugLoc &DL,
- uint64_t Offset) const;
+ const DebugLoc &DL, uint64_t Offset,
+ uint64_t Align) const;
void emitStackProbeInlineGenericLoop(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
- const DebugLoc &DL,
- uint64_t Offset) const;
+ const DebugLoc &DL, uint64_t Offset,
+ uint64_t Align) const;
/// Emit a stub to later inline the target stack probe.
MachineInstr *emitStackProbeInlineStub(MachineFunction &MF,
diff --git a/llvm/test/CodeGen/X86/stack-clash-large-large-align.ll b/llvm/test/CodeGen/X86/stack-clash-large-large-align.ll
new file mode 100644
index 000000000000..6c981cb4ac91
--- /dev/null
+++ b/llvm/test/CodeGen/X86/stack-clash-large-large-align.ll
@@ -0,0 +1,88 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo_noprotect() local_unnamed_addr {
+; CHECK-LABEL: foo_noprotect:
+; CHECK: # %bb.0:
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: .cfi_def_cfa_offset 16
+; CHECK-NEXT: .cfi_offset %rbp, -16
+; CHECK-NEXT: movq %rsp, %rbp
+; CHECK-NEXT: .cfi_def_cfa_register %rbp
+; CHECK-NEXT: andq $-4096, %rsp # imm = 0xF000
+; CHECK-NEXT: subq $73728, %rsp # imm = 0x12000
+; CHECK-NEXT: movl $1, 392(%rsp)
+; CHECK-NEXT: movl $1, 28792(%rsp)
+; CHECK-NEXT: movl (%rsp), %eax
+; CHECK-NEXT: movq %rbp, %rsp
+; CHECK-NEXT: popq %rbp
+; CHECK-NEXT: .cfi_def_cfa %rsp, 8
+; CHECK-NEXT: retq
+
+
+ %a = alloca i32, i64 18000, align 4096
+ %b0 = getelementptr inbounds i32, i32* %a, i64 98
+ %b1 = getelementptr inbounds i32, i32* %a, i64 7198
+ store volatile i32 1, i32* %b0
+ store volatile i32 1, i32* %b1
+ %c = load volatile i32, i32* %a
+ ret i32 %c
+}
+
+define i32 @foo_protect() local_unnamed_addr #0 {
+; CHECK-LABEL: foo_protect:
+; CHECK: # %bb.0:
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: .cfi_def_cfa_offset 16
+; CHECK-NEXT: .cfi_offset %rbp, -16
+; CHECK-NEXT: movq %rsp, %rbp
+; CHECK-NEXT: .cfi_def_cfa_register %rbp
+; CHECK-NEXT: movq %rsp, %r11
+; CHECK-NEXT: andq $-4096, %r11 # imm = 0xF000
+; CHECK-NEXT: cmpq %rsp, %r11
+; CHECK-NEXT: je .LBB1_4
+; CHECK-NEXT:# %bb.1:
+; CHECK-NEXT: subq $4096, %rsp # imm = 0x1000
+; CHECK-NEXT: cmpq %rsp, %r11
+; CHECK-NEXT: jb .LBB1_3
+; CHECK-NEXT:.LBB1_2: # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT: movq $0, (%rsp)
+; CHECK-NEXT: subq $4096, %rsp # imm = 0x1000
+; CHECK-NEXT: cmpq %rsp, %r11
+; CHECK-NEXT: jb .LBB1_2
+; CHECK-NEXT:.LBB1_3:
+; CHECK-NEXT: movq %r11, %rsp
+; CHECK-NEXT: movq $0, (%rsp)
+; CHECK-NEXT:.LBB1_4:
+; CHECK-NEXT: movq %rsp, %r11
+; CHECK-NEXT: subq $73728, %r11 # imm = 0x12000
+; CHECK-NEXT:.LBB1_5: # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT: subq $4096, %rsp # imm = 0x1000
+; CHECK-NEXT: movq $0, (%rsp)
+; CHECK-NEXT: cmpq %r11, %rsp
+; CHECK-NEXT: jne .LBB1_5
+; CHECK-NEXT:# %bb.6:
+; CHECK-NEXT: movl $1, 392(%rsp)
+; CHECK-NEXT: movl $1, 28792(%rsp)
+; CHECK-NEXT: movl (%rsp), %eax
+; CHECK-NEXT: movq %rbp, %rsp
+; CHECK-NEXT: popq %rbp
+; CHECK-NEXT: .cfi_def_cfa %rsp, 8
+; CHECK-NEXT: retq
+
+
+
+
+ %a = alloca i32, i64 18000, align 4096
+ %b0 = getelementptr inbounds i32, i32* %a, i64 98
+ %b1 = getelementptr inbounds i32, i32* %a, i64 7198
+ store volatile i32 1, i32* %b0
+ store volatile i32 1, i32* %b1
+ %c = load volatile i32, i32* %a
+ ret i32 %c
+}
+
+attributes #0 = {"probe-stack"="inline-asm"}
diff --git a/llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll b/llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
deleted file mode 100644
index 652acbdf00ba..000000000000
--- a/llvm/test/CodeGen/X86/stack-clash-no-free-probe.ll
+++ /dev/null
@@ -1,27 +0,0 @@
-; RUN: llc < %s | FileCheck %s
-
-target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
-target triple = "x86_64-unknown-linux-gnu"
-
-define i32 @foo(i64 %i) local_unnamed_addr #0 {
-; CHECK-LABEL: foo:
-; CHECK: # %bb.0:
-; CHECK-NEXT: subq $4096, %rsp # imm = 0x1000
-; CHECK-NEXT: movq $0, (%rsp)
-; CHECK-NEXT: subq $3784, %rsp # imm = 0xEC8
-; CHECK-NEXT: .cfi_def_cfa_offset 7888
-; CHECK-NEXT: movl $1, -128(%rsp,%rdi,4)
-; CHECK-NEXT: movl -128(%rsp), %eax
-; CHECK-NEXT: addq $7880, %rsp # imm = 0x1EC8
-; CHECK-NEXT: .cfi_def_cfa_offset 8
-; CHECK-NEXT: retq
-
- %a = alloca i32, i32 2000, align 16
- %b = getelementptr inbounds i32, i32* %a, i64 %i
- store volatile i32 1, i32* %b
- %c = load volatile i32, i32* %a
- ret i32 %c
-}
-
-attributes #0 = {"probe-stack"="inline-asm"}
-
diff --git a/llvm/test/CodeGen/X86/stack-clash-small-alloc-medium-align.ll b/llvm/test/CodeGen/X86/stack-clash-small-alloc-medium-align.ll
new file mode 100644
index 000000000000..eafa86f1eba9
--- /dev/null
+++ b/llvm/test/CodeGen/X86/stack-clash-small-alloc-medium-align.ll
@@ -0,0 +1,135 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; | case1 | alloca + align < probe_size
+define i32 @foo1(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo1:
+; CHECK: # %bb.0:
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: .cfi_def_cfa_offset 16
+; CHECK-NEXT: .cfi_offset %rbp, -16
+; CHECK-NEXT: movq %rsp, %rbp
+; CHECK-NEXT: .cfi_def_cfa_register %rbp
+; CHECK-NEXT: andq $-64, %rsp
+; CHECK-NEXT: subq $832, %rsp # imm = 0x340
+; CHECK-NEXT: movl $1, (%rsp,%rdi,4)
+; CHECK-NEXT: movl (%rsp), %eax
+; CHECK-NEXT: movq %rbp, %rsp
+; CHECK-NEXT: popq %rbp
+; CHECK-NEXT: .cfi_def_cfa %rsp, 8
+; CHECK-NEXT: retq
+
+ %a = alloca i32, i32 200, align 64
+ %b = getelementptr inbounds i32, i32* %a, i64 %i
+ store volatile i32 1, i32* %b
+ %c = load volatile i32, i32* %a
+ ret i32 %c
+}
+
+; | case2 | alloca > probe_size, align > probe_size
+define i32 @foo2(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo2:
+; CHECK: # %bb.0:
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: .cfi_def_cfa_offset 16
+; CHECK-NEXT: .cfi_offset %rbp, -16
+; CHECK-NEXT: movq %rsp, %rbp
+; CHECK-NEXT: .cfi_def_cfa_register %rbp
+; CHECK-NEXT: andq $-2048, %rsp # imm = 0xF800
+; CHECK-NEXT: subq $2048, %rsp # imm = 0x800
+; CHECK-NEXT: movq $0, (%rsp)
+; CHECK-NEXT: subq $4096, %rsp # imm = 0x1000
+; CHECK-NEXT: movq $0, (%rsp)
+; CHECK-NEXT: subq $2048, %rsp # imm = 0x800
+; CHECK-NEXT: movl $1, (%rsp,%rdi,4)
+; CHECK-NEXT: movl (%rsp), %eax
+; CHECK-NEXT: movq %rbp, %rsp
+; CHECK-NEXT: popq %rbp
+; CHECK-NEXT: .cfi_def_cfa %rsp, 8
+; CHECK-NEXT: retq
+
+ %a = alloca i32, i32 2000, align 2048
+ %b = getelementptr inbounds i32, i32* %a, i64 %i
+ store volatile i32 1, i32* %b
+ %c = load volatile i32, i32* %a
+ ret i32 %c
+}
+
+; | case3 | alloca < probe_size, align < probe_size, alloca + align > probe_size
+define i32 @foo3(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo3:
+; CHECK: # %bb.0:
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: .cfi_def_cfa_offset 16
+; CHECK-NEXT: .cfi_offset %rbp, -16
+; CHECK-NEXT: movq %rsp, %rbp
+; CHECK-NEXT: .cfi_def_cfa_register %rbp
+; CHECK-NEXT: andq $-1024, %rsp # imm = 0xFC00
+; CHECK-NEXT: subq $3072, %rsp # imm = 0xC00
+; CHECK-NEXT: movq $0, (%rsp)
+; CHECK-NEXT: subq $1024, %rsp # imm = 0x400
+; CHECK-NEXT: movl $1, (%rsp,%rdi,4)
+; CHECK-NEXT: movl (%rsp), %eax
+; CHECK-NEXT: movq %rbp, %rsp
+; CHECK-NEXT: popq %rbp
+; CHECK-NEXT: .cfi_def_cfa %rsp, 8
+; CHECK-NEXT: retq
+
+
+ %a = alloca i32, i32 1000, align 1024
+ %b = getelementptr inbounds i32, i32* %a, i64 %i
+ store volatile i32 1, i32* %b
+ %c = load volatile i32, i32* %a
+ ret i32 %c
+}
+
+; | case4 | alloca + probe_size < probe_size, followed by dynamic alloca
+define i32 @foo4(i64 %i) local_unnamed_addr #0 {
+; CHECK-LABEL: foo4:
+; CHECK: # %bb.0:
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: .cfi_def_cfa_offset 16
+; CHECK-NEXT: .cfi_offset %rbp, -16
+; CHECK-NEXT: movq %rsp, %rbp
+; CHECK-NEXT: .cfi_def_cfa_register %rbp
+; CHECK-NEXT: pushq %rbx
+; CHECK-NEXT: andq $-64, %rsp
+; CHECK-NEXT: subq $896, %rsp # imm = 0x380
+; CHECK-NEXT: movq %rsp, %rbx
+; CHECK-NEXT: .cfi_offset %rbx, -24
+; CHECK-NEXT: movl $1, (%rbx,%rdi,4)
+; CHECK-NEXT: movl (%rbx), %ecx
+; CHECK-NEXT: movq %rsp, %rax
+; CHECK-NEXT: leaq 15(,%rcx,4), %rcx
+; CHECK-NEXT: andq $-16, %rcx
+; CHECK-NEXT: subq %rcx, %rax
+; CHECK-NEXT: cmpq %rsp, %rax
+; CHECK-NEXT: jle .LBB3_3
+; CHECK-NEXT:.LBB3_2: # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT: movq $0, (%rsp)
+; CHECK-NEXT: subq $4096, %rsp # imm = 0x1000
+; CHECK-NEXT: cmpq %rsp, %rax
+; CHECK-NEXT: jg .LBB3_2
+; CHECK-NEXT:.LBB3_3:
+; CHECK-NEXT: andq $-64, %rax
+; CHECK-NEXT: movq %rax, %rsp
+; CHECK-NEXT: movl (%rax), %eax
+; CHECK-NEXT: leaq -8(%rbp), %rsp
+; CHECK-NEXT: popq %rbx
+; CHECK-NEXT: popq %rbp
+; CHECK-NEXT: .cfi_def_cfa %rsp, 8
+; CHECK-NEXT: retq
+
+ %a = alloca i32, i32 200, align 64
+ %b = getelementptr inbounds i32, i32* %a, i64 %i
+ store volatile i32 1, i32* %b
+ %c = load volatile i32, i32* %a
+ %d = alloca i32, i32 %c, align 64
+ %e = load volatile i32, i32* %d
+ ret i32 %e
+}
+
+attributes #0 = {"probe-stack"="inline-asm"}
+
diff --git a/llvm/test/CodeGen/X86/stack-clash-small-large-align.ll b/llvm/test/CodeGen/X86/stack-clash-small-large-align.ll
new file mode 100644
index 000000000000..e608bab90415
--- /dev/null
+++ b/llvm/test/CodeGen/X86/stack-clash-small-large-align.ll
@@ -0,0 +1,83 @@
+; RUN: llc < %s | FileCheck %s
+
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @foo_noprotect() local_unnamed_addr {
+; CHECK-LABEL: foo_noprotect:
+; CHECK: # %bb.0:
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: .cfi_def_cfa_offset 16
+; CHECK-NEXT: .cfi_offset %rbp, -16
+; CHECK-NEXT: movq %rsp, %rbp
+; CHECK-NEXT: .cfi_def_cfa_register %rbp
+; CHECK-NEXT: andq $-65536, %rsp
+; CHECK-NEXT: subq $65536, %rsp
+; CHECK-NEXT: movl $1, 392(%rsp)
+; CHECK-NEXT: movl (%rsp), %eax
+; CHECK-NEXT: movq %rbp, %rsp
+; CHECK-NEXT: popq %rbp
+; CHECK-NEXT: .cfi_def_cfa %rsp, 8
+; CHECK-NEXT: retq
+
+
+
+ %a = alloca i32, i64 100, align 65536
+ %b = getelementptr inbounds i32, i32* %a, i64 98
+ store volatile i32 1, i32* %b
+ %c = load volatile i32, i32* %a
+ ret i32 %c
+}
+
+define i32 @foo_protect() local_unnamed_addr #0 {
+; CHECK-LABEL: foo_protect:
+; CHECK: # %bb.0:
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: .cfi_def_cfa_offset 16
+; CHECK-NEXT: .cfi_offset %rbp, -16
+; CHECK-NEXT: movq %rsp, %rbp
+; CHECK-NEXT: .cfi_def_cfa_register %rbp
+; CHECK-NEXT: movq %rsp, %r11
+; CHECK-NEXT: andq $-65536, %r11 # imm = 0xFFFF0000
+; CHECK-NEXT: cmpq %rsp, %r11
+; CHECK-NEXT: je .LBB1_4
+; CHECK-NEXT:# %bb.1:
+; CHECK-NEXT: subq $4096, %rsp # imm = 0x1000
+; CHECK-NEXT: cmpq %rsp, %r11
+; CHECK-NEXT: jb .LBB1_3
+; CHECK-NEXT:.LBB1_2: # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT: movq $0, (%rsp)
+; CHECK-NEXT: subq $4096, %rsp # imm = 0x1000
+; CHECK-NEXT: cmpq %rsp, %r11
+; CHECK-NEXT: jb .LBB1_2
+; CHECK-NEXT:.LBB1_3:
+; CHECK-NEXT: movq %r11, %rsp
+; CHECK-NEXT: movq $0, (%rsp)
+; CHECK-NEXT:.LBB1_4:
+; CHECK-NEXT: movq %rsp, %r11
+; CHECK-NEXT: subq $65536, %r11 # imm = 0x10000
+; CHECK-NEXT:.LBB1_5: # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT: subq $4096, %rsp # imm = 0x1000
+; CHECK-NEXT: movq $0, (%rsp)
+; CHECK-NEXT: cmpq %r11, %rsp
+; CHECK-NEXT: jne .LBB1_5
+; CHECK-NEXT:# %bb.6:
+; CHECK-NEXT: movl $1, 392(%rsp)
+; CHECK-NEXT: movl (%rsp), %eax
+; CHECK-NEXT: movq %rbp, %rsp
+; CHECK-NEXT: popq %rbp
+; CHECK-NEXT: .cfi_def_cfa %rsp, 8
+; CHECK-NEXT: retq
+
+
+
+
+ %a = alloca i32, i64 100, align 65536
+ %b = getelementptr inbounds i32, i32* %a, i64 98
+ store volatile i32 1, i32* %b
+ %c = load volatile i32, i32* %a
+ ret i32 %c
+}
+
+attributes #0 = {"probe-stack"="inline-asm"}
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