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llvm-project/llvm/test/CodeGen/X86/nocf_check.ll

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[X86][CET] Changing -fcf-protection behavior to comply with gcc (LLVM part) This patch aims to match the changes introduced in gcc by https://gcc.gnu.org/ml/gcc-cvs/2018-04/msg00534.html. The IBT feature definition is removed, with the IBT instructions being freely available on all X86 targets. The shadow stack instructions are also being made freely available, and the use of all these CET instructions is controlled by the module flags derived from the -fcf-protection clang option. The hasSHSTK option remains since clang uses it to determine availability of shadow stack instruction intrinsics, but it is no longer directly used. Comes with a clang patch (D46881). Patch by mike.dvoretsky Differential Revision: https://reviews.llvm.org/D46882 llvm-svn: 332705
2018-05-18 19:58:25 +08:00
; RUN: llc -mtriple=x86_64-unknown-unknown -x86-indirect-branch-tracking < %s | FileCheck %s
[X86] Added support for nocf_check attribute for indirect Branch Tracking X86 Supports Indirect Branch Tracking (IBT) as part of Control-Flow Enforcement Technology (CET). IBT instruments ENDBR instructions used to specify valid targets of indirect call / jmp. The `nocf_check` attribute has two roles in the context of X86 IBT technology: 1. Appertains to a function - do not add ENDBR instruction at the beginning of the function. 2. Appertains to a function pointer - do not track the target function of this pointer by adding nocf_check prefix to the indirect-call instruction. This patch implements `nocf_check` context for Indirect Branch Tracking. It also auto generates `nocf_check` prefixes before indirect branchs to jump tables that are guarded by range checks. Differential Revision: https://reviews.llvm.org/D41879 llvm-svn: 327767
2018-03-17 21:29:46 +08:00
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; This test verify the handling of ''nocf_check'' attribute by the backend. ;;
;; The file was generated using the following C code: ;;
;; ;;
;; void __attribute__((nocf_check)) NoCfCheckFunc(void) {} ;;
;; ;;
;; typedef void(*FuncPointer)(void); ;;
;; void NoCfCheckCall(FuncPointer f) { ;;
;; __attribute__((nocf_check)) FuncPointer p = f; ;;
;; (*p)(); ;;
;; } ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Make sure that a function with ''nocf_check'' attribute is not instrumented
; with endbr instruction at the beginning.
define void @NoCfCheckFunc() #0 {
; CHECK-LABEL: NoCfCheckFunc
; CHECK-NOT: endbr64
; CHECK: retq
entry:
ret void
}
; Make sure that notrack prefix is added before a call with ''nocf_check'' attribute.
define void @NoCfCheckCall(void ()* %f) {
; CHECK-LABEL: NoCfCheckCall
; CHECK: notrack call
entry:
%f.addr = alloca void ()*, align 4
%p = alloca void ()*, align 4
store void ()* %f, void ()** %f.addr, align 4
%0 = load void ()*, void ()** %f.addr, align 4
store void ()* %0, void ()** %p, align 4
%1 = load void ()*, void ()** %p, align 4
call void %1() #1
ret void
}
attributes #0 = { noinline nocf_check nounwind optnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { nocf_check }
!llvm.module.flags = !{!0}
!0 = !{i32 4, !"cf-protection-branch", i32 1}