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[LLVM] Add stackprobe patch to fix i686-linux-gnu segfaults (JuliaPac…
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…kaging#3582)

On i686-linux-gnu, enabling stackprobes caused register clobbering,
which manifested in segfaults in certain rare cases [0].  This ended up
being because a register was incorrectly specified; this patch rectifies
the issue and is confirmed to eliminate the segfaults.  It has been
accepted by upstream [1].

[0] JuliaLang/julia#41528
[1] https://reviews.llvm.org/D109203
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@staticfloat @simeonschaub
staticfloat authored and simeonschaub committed Feb 23, 2022
1 parent 8f3b27b commit 4b2f829
Showing 1 changed file with 135 additions and 0 deletions.
135 changes: 135 additions & 0 deletions L/LLVM/LLVM_full@12.0.1/bundled/patches/0300-D109203-stackprobe-x86.patch
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Original file line number Diff line number Diff line change
@@ -0,0 +1,135 @@
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -652,7 +652,9 @@
MF.insert(MBBIter, testMBB);
MF.insert(MBBIter, tailMBB);

- Register FinalStackProbed = Uses64BitFramePtr ? X86::R11 : X86::R11D;
+ Register FinalStackProbed = Uses64BitFramePtr ? X86::R11
+ : Is64Bit ? X86::R11D
+ : X86::EAX;
BuildMI(MBB, MBBI, DL, TII.get(TargetOpcode::COPY), FinalStackProbed)
.addReg(StackPtr)
.setMIFlag(MachineInstr::FrameSetup);
@@ -1073,7 +1075,9 @@
MF.insert(MBBIter, bodyMBB);
MF.insert(MBBIter, footMBB);
const unsigned MovMIOpc = Is64Bit ? X86::MOV64mi32 : X86::MOV32mi;
- Register FinalStackProbed = Uses64BitFramePtr ? X86::R11 : X86::R11D;
+ Register FinalStackProbed = Uses64BitFramePtr ? X86::R11
+ : Is64Bit ? X86::R11D
+ : X86::EAX;

// Setup entry block
{
diff --git a/llvm/test/CodeGen/X86/stack-clash-large.ll b/llvm/test/CodeGen/X86/stack-clash-large.ll
--- a/llvm/test/CodeGen/X86/stack-clash-large.ll
+++ b/llvm/test/CodeGen/X86/stack-clash-large.ll
@@ -1,5 +1,6 @@
-; RUN: llc -mtriple=x86_64-linux-android < %s | FileCheck -check-prefix=CHECK-X86-64 %s
-; RUN: llc -mtriple=i686-linux-android < %s | FileCheck -check-prefix=CHECK-X86-32 %s
+; RUN: llc -mtriple=x86_64-linux-android < %s | FileCheck -check-prefix=CHECK-X64 %s
+; RUN: llc -mtriple=i686-linux-android < %s | FileCheck -check-prefix=CHECK-X86 %s
+; RUN: llc -mtriple=x86_64-linux-gnux32 < %s | FileCheck -check-prefix=CHECK-X32 %s

define i32 @foo() local_unnamed_addr #0 {

@@ -14,40 +15,60 @@

attributes #0 = {"probe-stack"="inline-asm"}

-; CHECK-X86-64-LABEL: foo:
-; CHECK-X86-64: # %bb.0:
-; CHECK-X86-64-NEXT: movq %rsp, %r11
-; CHECK-X86-64-NEXT: subq $69632, %r11 # imm = 0x11000
-; CHECK-X86-64-NEXT: .LBB0_1:
-; CHECK-X86-64-NEXT: subq $4096, %rsp # imm = 0x1000
-; CHECK-X86-64-NEXT: movq $0, (%rsp)
-; CHECK-X86-64-NEXT: cmpq %r11, %rsp
-; CHECK-X86-64-NEXT: jne .LBB0_1
-; CHECK-X86-64-NEXT:# %bb.2:
-; CHECK-X86-64-NEXT: subq $2248, %rsp
-; CHECK-X86-64-NEXT: .cfi_def_cfa_offset 71888
-; CHECK-X86-64-NEXT: movl $1, 264(%rsp)
-; CHECK-X86-64-NEXT: movl $1, 28664(%rsp)
-; CHECK-X86-64-NEXT: movl -128(%rsp), %eax
-; CHECK-X86-64-NEXT: addq $71880, %rsp # imm = 0x118C8
-; CHECK-X86-64-NEXT: .cfi_def_cfa_offset 8
-; CHECK-X86-64-NEXT: retq
+; CHECK-X64-LABEL: foo:
+; CHECK-X64: # %bb.0:
+; CHECK-X64-NEXT: movq %rsp, %r11
+; CHECK-X64-NEXT: subq $69632, %r11 # imm = 0x11000
+; CHECK-X64-NEXT: .LBB0_1:
+; CHECK-X64-NEXT: subq $4096, %rsp # imm = 0x1000
+; CHECK-X64-NEXT: movq $0, (%rsp)
+; CHECK-X64-NEXT: cmpq %r11, %rsp
+; CHECK-X64-NEXT: jne .LBB0_1
+; CHECK-X64-NEXT:# %bb.2:
+; CHECK-X64-NEXT: subq $2248, %rsp
+; CHECK-X64-NEXT: .cfi_def_cfa_offset 71888
+; CHECK-X64-NEXT: movl $1, 264(%rsp)
+; CHECK-X64-NEXT: movl $1, 28664(%rsp)
+; CHECK-X64-NEXT: movl -128(%rsp), %eax
+; CHECK-X64-NEXT: addq $71880, %rsp # imm = 0x118C8
+; CHECK-X64-NEXT: .cfi_def_cfa_offset 8
+; CHECK-X64-NEXT: retq
+
+; CHECK-X86-LABEL: foo:
+; CHECK-X86: # %bb.0:
+; CHECK-X86-NEXT: movl %esp, %eax
+; CHECK-X86-NEXT: subl $69632, %eax # imm = 0x11000
+; CHECK-X86-NEXT: .LBB0_1: # =>This Inner Loop Header: Depth=1
+; CHECK-X86-NEXT: subl $4096, %esp # imm = 0x1000
+; CHECK-X86-NEXT: movl $0, (%esp)
+; CHECK-X86-NEXT: cmpl %eax, %esp
+; CHECK-X86-NEXT: jne .LBB0_1
+; CHECK-X86-NEXT:# %bb.2:
+; CHECK-X86-NEXT: subl $2380, %esp
+; CHECK-X86-NEXT: .cfi_def_cfa_offset 72016
+; CHECK-X86-NEXT: movl $1, 392(%esp)
+; CHECK-X86-NEXT: movl $1, 28792(%esp)
+; CHECK-X86-NEXT: movl (%esp), %eax
+; CHECK-X86-NEXT: addl $72012, %esp # imm = 0x1194C
+; CHECK-X86-NEXT: .cfi_def_cfa_offset 4
+; CHECK-X86-NEXT: retl
+
+; CHECK-X32-LABEL: foo:
+; CHECK-X32: # %bb.0:
+; CHECK-X32-NEXT: movl %esp, %r11d
+; CHECK-X32-NEXT: subl $69632, %r11d # imm = 0x11000
+; CHECK-X32-NEXT: .LBB0_1: # =>This Inner Loop Header: Depth=1
+; CHECK-X32-NEXT: subl $4096, %esp # imm = 0x1000
+; CHECK-X32-NEXT: movq $0, (%esp)
+; CHECK-X32-NEXT: cmpl %r11d, %esp
+; CHECK-X32-NEXT: jne .LBB0_1
+; CHECK-X32-NEXT:# %bb.2:
+; CHECK-X32-NEXT: subl $2248, %esp
+; CHECK-X32-NEXT: .cfi_def_cfa_offset 71888
+; CHECK-X32-NEXT: movl $1, 264(%esp)
+; CHECK-X32-NEXT: movl $1, 28664(%esp)
+; CHECK-X32-NEXT: movl -128(%esp), %eax
+; CHECK-X32-NEXT: addl $71880, %esp # imm = 0x118C8
+; CHECK-X32-NEXT: .cfi_def_cfa_offset 8
+; CHECK-X32-NEXT: retq

-; CHECK-X86-32-LABEL: foo:
-; CHECK-X86-32: # %bb.0:
-; CHECK-X86-32-NEXT: movl %esp, %r11d
-; CHECK-X86-32-NEXT: subl $69632, %r11d # imm = 0x11000
-; CHECK-X86-32-NEXT: .LBB0_1: # =>This Inner Loop Header: Depth=1
-; CHECK-X86-32-NEXT: subl $4096, %esp # imm = 0x1000
-; CHECK-X86-32-NEXT: movl $0, (%esp)
-; CHECK-X86-32-NEXT: cmpl %r11d, %esp
-; CHECK-X86-32-NEXT: jne .LBB0_1
-; CHECK-X86-32-NEXT:# %bb.2:
-; CHECK-X86-32-NEXT: subl $2380, %esp
-; CHECK-X86-32-NEXT: .cfi_def_cfa_offset 72016
-; CHECK-X86-32-NEXT: movl $1, 392(%esp)
-; CHECK-X86-32-NEXT: movl $1, 28792(%esp)
-; CHECK-X86-32-NEXT: movl (%esp), %eax
-; CHECK-X86-32-NEXT: addl $72012, %esp # imm = 0x1194C
-; CHECK-X86-32-NEXT: .cfi_def_cfa_offset 4
-; CHECK-X86-32-NEXT: retl

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