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Differential D70741

[X86] [Win64] Avoid truncating large (> 32 bit) stack allocations
ClosedPublic

Authored by mstorsjo on Nov 26 2019, 12:46 PM.

Details

Reviewers
rnk
nagisa
Commits
rG943513b79929: [X86] [Win64] Avoid truncating large (> 32 bit) stack allocations
Summary

This fixes PR44129, which was broken in a7adc3185b (in 7.0.0 and newer).

Diff Detail

Event Timeline

mstorsjo created this revision.Nov 26 2019, 12:46 PM
Herald added a project: Restricted Project. · View Herald TranscriptNov 26 2019, 12:46 PM
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rnk accepted this revision.Nov 26 2019, 3:41 PM

lgtm, thanks!

This revision is now accepted and ready to land.Nov 26 2019, 3:41 PM
Closed by commit rG943513b79929: [X86] [Win64] Avoid truncating large (> 32 bit) stack allocations (authored by mstorsjo). · Explain WhyNov 27 2019, 12:51 AM
This revision was automatically updated to reflect the committed changes.

Revision Contents

PathSize
llvm/
lib/
Target/
X86/
2 lines
test/
CodeGen/
X86/
14 lines

Diff 231123

llvm/lib/Target/X86/X86FrameLowering.cpp

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.addReg(X86::EAX, RegState::Kill) .addReg(X86::EAX, RegState::Kill)
.setMIFlag(MachineInstr::FrameSetup); .setMIFlag(MachineInstr::FrameSetup);
} }
} }
if (Is64Bit) { if (Is64Bit) {
// Handle the 64-bit Windows ABI case where we need to call __chkstk. // Handle the 64-bit Windows ABI case where we need to call __chkstk.
// Function prologue is responsible for adjusting the stack pointer. // Function prologue is responsible for adjusting the stack pointer.
int Alloc = isEAXAlive ? NumBytes - 8 : NumBytes; int64_t Alloc = isEAXAlive ? NumBytes - 8 : NumBytes;
if (isUInt<32>(Alloc)) { if (isUInt<32>(Alloc)) {
BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX) BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
.addImm(Alloc) .addImm(Alloc)
.setMIFlag(MachineInstr::FrameSetup); .setMIFlag(MachineInstr::FrameSetup);
} else if (isInt<32>(Alloc)) { } else if (isInt<32>(Alloc)) {
BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64ri32), X86::RAX) BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64ri32), X86::RAX)
.addImm(Alloc) .addImm(Alloc)
.setMIFlag(MachineInstr::FrameSetup); .setMIFlag(MachineInstr::FrameSetup);
▲ Show 20 Lines • Show All 991 Lines • Show Last 20 Lines

llvm/test/CodeGen/X86/win64-stackprobe-overflow.ll

  • This file was added.
; RUN: llc < %s -mtriple=x86_64-windows-gnu | FileCheck %s
define void @foo() unnamed_addr #0 {
start:
%b = alloca i64, align 8
%c = alloca [4294967295 x i8], align 1
ret void
}
attributes #0 = { nonlazybind uwtable "probe-stack"="probe_stack" "target-cpu"="x86-64" }
; CHECK-LABEL: foo:
; CHECK: movabsq $4294967304, %rax
; CHECK-NEXT: callq probe_stack