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41f4d00801
This intrinsic safely loads a function pointer from a virtual table pointer using type metadata. This intrinsic is used to implement control flow integrity in conjunction with virtual call optimization. The virtual call optimization pass will optimize away llvm.type.checked.load intrinsics associated with devirtualized calls, thereby removing the type check in cases where it is not needed to enforce the control flow integrity constraint. This patch also introduces the capability to copy type metadata between global variables, and teaches the virtual call optimization pass to do so. Differential Revision: http://reviews.llvm.org/D21121 llvm-svn: 273756
64 lines
2.1 KiB
LLVM
64 lines
2.1 KiB
LLVM
; RUN: opt -S -wholeprogramdevirt %s | FileCheck %s
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; Test that we correctly expand the llvm.type.checked.load intrinsic in cases
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; where we cannot devirtualize.
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target datalayout = "e-p:64:64"
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target triple = "x86_64-unknown-linux-gnu"
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@vt1 = constant [1 x i8*] [i8* bitcast (void (i8*)* @vf1 to i8*)], !type !0
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@vt2 = constant [1 x i8*] [i8* bitcast (void (i8*)* @vf2 to i8*)], !type !0
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define void @vf1(i8* %this) {
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ret void
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}
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define void @vf2(i8* %this) {
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ret void
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}
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; CHECK: define void @call
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define void @call(i8* %obj) {
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%vtableptr = bitcast i8* %obj to [1 x i8*]**
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%vtable = load [1 x i8*]*, [1 x i8*]** %vtableptr
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%vtablei8 = bitcast [1 x i8*]* %vtable to i8*
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%pair = call {i8*, i1} @llvm.type.checked.load(i8* %vtablei8, i32 0, metadata !"typeid")
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%p = extractvalue {i8*, i1} %pair, 1
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; CHECK: [[TT:%[^ ]*]] = call i1 @llvm.type.test(i8* [[VT:%[^,]*]], metadata !"typeid")
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; CHECK: br i1 [[TT]],
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br i1 %p, label %cont, label %trap
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cont:
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; CHECK: [[GEP:%[^ ]*]] = getelementptr i8, i8* [[VT]], i32 0
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; CHECK: [[BC:%[^ ]*]] = bitcast i8* [[GEP]] to i8**
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; CHECK: [[LOAD:%[^ ]*]] = load i8*, i8** [[BC]]
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; CHECK: [[FPC:%[^ ]*]] = bitcast i8* [[LOAD]] to void (i8*)*
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; CHECK: call void [[FPC]]
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%fptr = extractvalue {i8*, i1} %pair, 0
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%fptr_casted = bitcast i8* %fptr to void (i8*)*
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call void %fptr_casted(i8* %obj)
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ret void
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trap:
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call void @llvm.trap()
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unreachable
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}
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; CHECK: define { i8*, i1 } @ret
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define {i8*, i1} @ret(i8* %vtablei8) {
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; CHECK: [[GEP2:%[^ ]*]] = getelementptr i8, i8* [[VT2:%[^,]*]], i32 1
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; CHECK: [[BC2:%[^ ]*]] = bitcast i8* [[GEP2]] to i8**
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; CHECK: [[LOAD2:%[^ ]*]] = load i8*, i8** [[BC2]]
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; CHECK: [[TT2:%[^ ]*]] = call i1 @llvm.type.test(i8* [[VT2]], metadata !"typeid")
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; CHECK: [[I1:%[^ ]*]] = insertvalue { i8*, i1 } undef, i8* [[LOAD2]], 0
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; CHECK: [[I2:%[^ ]*]] = insertvalue { i8*, i1 } %5, i1 [[TT2]], 1
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%pair = call {i8*, i1} @llvm.type.checked.load(i8* %vtablei8, i32 1, metadata !"typeid")
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; CHECK: ret { i8*, i1 } [[I2]]
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ret {i8*, i1} %pair
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}
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declare {i8*, i1} @llvm.type.checked.load(i8*, i32, metadata)
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declare void @llvm.trap()
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!0 = !{i32 0, !"typeid"}
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