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

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

Differential Revision: https://reviews.llvm.org/D70741
This commit is contained in:
Martin Storsjö 2019-11-26 22:41:40 +02:00
parent 344bdeb797
commit 943513b799
2 changed files with 15 additions and 1 deletions
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2
llvm/lib/Target/X86/X86FrameLowering.cpp
View File

@ -1261,7 +1261,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF,
if (Is64Bit) {
// Handle the 64-bit Windows ABI case where we need to call __chkstk.
// 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)) {
BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
.addImm(Alloc)

14
llvm/test/CodeGen/X86/win64-stackprobe-overflow.ll Normal file
View File

@ -0,0 +1,14 @@
; 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