llvm-6502/test/CodeGen/X86/stack_guard_remat.ll
Akira Hatanaka 0651a556fe [stack protector] Fix a potential security bug in stack protector where the
address of the stack guard was being spilled to the stack.

Previously the address of the stack guard would get spilled to the stack if it
was impossible to keep it in a register. This patch introduces a new target
independent node and pseudo instruction which gets expanded post-RA to a
sequence of instructions that load the stack guard value. Register allocator
can now just remat the value when it can't keep it in a register. 

<rdar://problem/12475629>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213967 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-25 19:31:34 +00:00

29 lines
1.2 KiB
LLVM

; RUN: llc < %s -mtriple=x86_64-apple-darwin -no-integrated-as | FileCheck %s -check-prefix=CHECK
;CHECK: foo2
;CHECK: movq ___stack_chk_guard@GOTPCREL(%rip), [[R0:%[a-z0-9]+]]
;CHECK: movq ([[R0]]), {{%[a-z0-9]+}}
; Function Attrs: nounwind ssp uwtable
define i32 @test_stack_guard_remat() #0 {
entry:
%a1 = alloca [256 x i32], align 16
%0 = bitcast [256 x i32]* %a1 to i8*
call void @llvm.lifetime.start(i64 1024, i8* %0)
%arraydecay = getelementptr inbounds [256 x i32]* %a1, i64 0, i64 0
call void @foo3(i32* %arraydecay)
call void asm sideeffect "foo2", "~{r12},~{r13},~{r14},~{r15},~{ebx},~{esi},~{edi},~{dirflag},~{fpsr},~{flags}"()
call void @llvm.lifetime.end(i64 1024, i8* %0)
ret i32 0
}
; Function Attrs: nounwind
declare void @llvm.lifetime.start(i64, i8* nocapture)
declare void @foo3(i32*)
; Function Attrs: nounwind
declare void @llvm.lifetime.end(i64, i8* nocapture)
attributes #0 = { nounwind ssp uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }