[llvm] r358807 - [X86] Fix stack probing on x32 (PR41477)
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Sat Apr 20 00:25:46 PDT 2019
Author: nikic
Date: Sat Apr 20 00:25:46 2019
New Revision: 358807
URL: http://llvm.org/viewvc/llvm-project?rev=358807&view=rev
Log:
[X86] Fix stack probing on x32 (PR41477)
Fix for https://bugs.llvm.org/show_bug.cgi?id=41477. On the x32 ABI
with stack probing a dynamic alloca will result in a WIN_ALLOCA_32
with a 32-bit size. The current implementation tries to copy it into
RAX, resulting in a physreg copy error. Fix this by copying to EAX
instead. Also fix incorrect opcodes or registers used in subs.
Added:
llvm/trunk/test/CodeGen/X86/probe-stack-x32.ll
Modified:
llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
llvm/trunk/lib/Target/X86/X86WinAllocaExpander.cpp
Modified: llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FrameLowering.cpp?rev=358807&r1=358806&r2=358807&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86FrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86FrameLowering.cpp Sat Apr 20 00:25:46 2019
@@ -794,8 +794,8 @@ void X86FrameLowering::emitStackProbeCal
.addExternalSymbol(MF.createExternalSymbolName(Symbol));
}
- unsigned AX = Is64Bit ? X86::RAX : X86::EAX;
- unsigned SP = Is64Bit ? X86::RSP : X86::ESP;
+ unsigned AX = Uses64BitFramePtr ? X86::RAX : X86::EAX;
+ unsigned SP = Uses64BitFramePtr ? X86::RSP : X86::ESP;
CI.addReg(AX, RegState::Implicit)
.addReg(SP, RegState::Implicit)
.addReg(AX, RegState::Define | RegState::Implicit)
@@ -809,7 +809,7 @@ void X86FrameLowering::emitStackProbeCal
// adjusting %rsp.
// All other platforms do not specify a particular ABI for the stack probe
// function, so we arbitrarily define it to not adjust %esp/%rsp itself.
- BuildMI(MBB, MBBI, DL, TII.get(getSUBrrOpcode(Is64Bit)), SP)
+ BuildMI(MBB, MBBI, DL, TII.get(getSUBrrOpcode(Uses64BitFramePtr)), SP)
.addReg(SP)
.addReg(AX);
}
Modified: llvm/trunk/lib/Target/X86/X86WinAllocaExpander.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86WinAllocaExpander.cpp?rev=358807&r1=358806&r2=358807&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86WinAllocaExpander.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86WinAllocaExpander.cpp Sat Apr 20 00:25:46 2019
@@ -209,15 +209,18 @@ void X86WinAllocaExpander::lower(Machine
return;
}
+ // These two variables differ on x32, which is a 64-bit target with a
+ // 32-bit alloca.
bool Is64Bit = STI->is64Bit();
+ bool Is64BitAlloca = MI->getOpcode() == X86::WIN_ALLOCA_64;
assert(SlotSize == 4 || SlotSize == 8);
- unsigned RegA = (SlotSize == 8) ? X86::RAX : X86::EAX;
switch (L) {
- case TouchAndSub:
+ case TouchAndSub: {
assert(Amount >= SlotSize);
// Use a push to touch the top of the stack.
+ unsigned RegA = Is64Bit ? X86::RAX : X86::EAX;
BuildMI(*MBB, I, DL, TII->get(Is64Bit ? X86::PUSH64r : X86::PUSH32r))
.addReg(RegA, RegState::Undef);
Amount -= SlotSize;
@@ -226,15 +229,18 @@ void X86WinAllocaExpander::lower(Machine
// Fall through to make any remaining adjustment.
LLVM_FALLTHROUGH;
+ }
case Sub:
assert(Amount > 0);
if (Amount == SlotSize) {
// Use push to save size.
+ unsigned RegA = Is64Bit ? X86::RAX : X86::EAX;
BuildMI(*MBB, I, DL, TII->get(Is64Bit ? X86::PUSH64r : X86::PUSH32r))
.addReg(RegA, RegState::Undef);
} else {
// Sub.
- BuildMI(*MBB, I, DL, TII->get(getSubOpcode(Is64Bit, Amount)), StackPtr)
+ BuildMI(*MBB, I, DL,
+ TII->get(getSubOpcode(Is64BitAlloca, Amount)), StackPtr)
.addReg(StackPtr)
.addImm(Amount);
}
@@ -242,6 +248,7 @@ void X86WinAllocaExpander::lower(Machine
case Probe:
if (!NoStackArgProbe) {
// The probe lowering expects the amount in RAX/EAX.
+ unsigned RegA = Is64BitAlloca ? X86::RAX : X86::EAX;
BuildMI(*MBB, MI, DL, TII->get(TargetOpcode::COPY), RegA)
.addReg(MI->getOperand(0).getReg());
@@ -250,8 +257,8 @@ void X86WinAllocaExpander::lower(Machine
/*InPrologue=*/false);
} else {
// Sub
- BuildMI(*MBB, I, DL, TII->get(Is64Bit ? X86::SUB64rr : X86::SUB32rr),
- StackPtr)
+ BuildMI(*MBB, I, DL,
+ TII->get(Is64BitAlloca ? X86::SUB64rr : X86::SUB32rr), StackPtr)
.addReg(StackPtr)
.addReg(MI->getOperand(0).getReg());
}
Added: llvm/trunk/test/CodeGen/X86/probe-stack-x32.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/probe-stack-x32.ll?rev=358807&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/probe-stack-x32.ll (added)
+++ llvm/trunk/test/CodeGen/X86/probe-stack-x32.ll Sat Apr 20 00:25:46 2019
@@ -0,0 +1,54 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnux32 -verify-machineinstrs | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnux32"
+
+; probe-stack + dynamic size alloca
+define void @test1(i32 %size) nounwind #0 {
+; CHECK-LABEL: test1:
+; CHECK: # %bb.0: # %start
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: movl %esp, %ebp
+; CHECK-NEXT: # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT: leal 15(%rdi), %eax
+; CHECK-NEXT: andl $-16, %eax
+; CHECK-NEXT: callq __rust_probestack
+; CHECK-NEXT: subl %eax, %esp
+start:
+ %alloca = alloca i8, i32 %size
+ unreachable
+}
+
+; probe-stack + no-stack-arg-probe + dynamic size alloca
+define void @test2(i32 %size) nounwind #1 {
+; CHECK-LABEL: test2:
+; CHECK: # %bb.0: # %start
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: movl %esp, %ebp
+; CHECK-NEXT: addl $15, %edi
+; CHECK-NEXT: andl $-16, %edi
+; CHECK-NEXT: subl %edi, %esp
+start:
+ %alloca = alloca i8, i32 %size
+ unreachable
+}
+
+; probe-stack + fixed size alloca not in entry block
+define void @test3() nounwind #0 {
+; CHECK-LABEL: test3:
+; CHECK: # %bb.0: # %start
+; CHECK-NEXT: pushq %rbp
+; CHECK-NEXT: movl %esp, %ebp
+; CHECK-NEXT: pushq %rax
+; CHECK-NEXT: subl $1992, %esp # imm = 0x7C8
+start:
+ br label %block
+
+block:
+ %alloca = alloca i8, i32 2000
+ unreachable
+}
+
+attributes #0 = { "probe-stack"="__rust_probestack" }
+attributes #1 = { "probe-stack"="__rust_probestack" "no-stack-arg-probe" }
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