[llvm] ae8507b - [X86] Don't clobber EBX in stackprobes
Jameson Nash via llvm-commits
llvm-commits at lists.llvm.org
Tue Sep 7 12:01:26 PDT 2021
Author: Elliot Saba
Date: 2021-09-07T15:00:44-04:00
New Revision: ae8507b0df738205a6b9e3795ad34672b7499381
URL: https://github.com/llvm/llvm-project/commit/ae8507b0df738205a6b9e3795ad34672b7499381
DIFF: https://github.com/llvm/llvm-project/commit/ae8507b0df738205a6b9e3795ad34672b7499381.diff
LOG: [X86] Don't clobber EBX in stackprobes
On X86, the stackprobe emission code chooses the `R11D` register, which
is illegal on i686. This ends up wrapping around to `EBX`, which does
not get properly callee-saved within the stack probing prologue,
clobbering the register for the callers.
We fix this by explicitly using `EAX` as the stack probe register.
Reviewed By: pengfei
Differential Revision: https://reviews.llvm.org/D109203
Added:
Modified:
llvm/lib/Target/X86/X86FrameLowering.cpp
llvm/test/CodeGen/X86/stack-clash-large.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
index 4d25129290f8..a2b81a41e747 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -671,7 +671,9 @@ void X86FrameLowering::emitStackProbeInlineGenericLoop(
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);
@@ -1092,7 +1094,9 @@ void X86FrameLowering::BuildStackAlignAND(MachineBasicBlock &MBB,
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
index 9129e4ed40fd..00c7843b54f5 100644
--- a/llvm/test/CodeGen/X86/stack-clash-large.ll
+++ b/llvm/test/CodeGen/X86/stack-clash-large.ll
@@ -1,45 +1,64 @@
-; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --no_x86_scrub_sp
-; 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 {
-; 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: # =>This Inner Loop Header: Depth=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 # imm = 0x8C8
-; 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: # =>This Inner Loop Header: Depth=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 # imm = 0x8C8
+; 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-X86-32-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 # imm = 0x94C
-; 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
+; 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 # imm = 0x94C
+; 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 # imm = 0x8C8
+; 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
%a = alloca i32, i64 18000, align 16
%b0 = getelementptr inbounds i32, i32* %a, i64 98
%b1 = getelementptr inbounds i32, i32* %a, i64 7198
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