e44acadf6a
Similarly to CFI on virtual and indirect calls, this implementation tries to use program type information to make the checks as precise as possible. The basic way that it works is as follows, where `C` is the name of the class being defined or the target of a call and the function type is assumed to be `void()`. For virtual calls: - Attach type metadata to the addresses of function pointers in vtables (not the functions themselves) of type `void (B::*)()` for each `B` that is a recursive dynamic base class of `C`, including `C` itself. This type metadata has an annotation that the type is for virtual calls (to distinguish it from the non-virtual case). - At the call site, check that the computed address of the function pointer in the vtable has type `void (C::*)()`. For non-virtual calls: - Attach type metadata to each non-virtual member function whose address can be taken with a member function pointer. The type of a function in class `C` of type `void()` is each of the types `void (B::*)()` where `B` is a most-base class of `C`. A most-base class of `C` is defined as a recursive base class of `C`, including `C` itself, that does not have any bases. - At the call site, check that the function pointer has one of the types `void (B::*)()` where `B` is a most-base class of `C`. Differential Revision: https://reviews.llvm.org/D47567 llvm-svn: 335569
31 lines
1.2 KiB
C++
31 lines
1.2 KiB
C++
// RUN: %clang_cc1 -triple x86_64-unknown-linux -fsanitize=cfi-mfcall -fsanitize-trap=cfi-mfcall -fvisibility hidden -emit-llvm -o - %s | FileCheck %s
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// RUN: %clang_cc1 -triple x86_64-unknown-linux -fsanitize=cfi-mfcall -fsanitize-trap=cfi-mfcall -fvisibility default -emit-llvm -o - %s | FileCheck --check-prefix=DEFAULT %s
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struct B1 {};
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struct B2 {};
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struct B3 : B2 {};
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struct S : B1, B3 {};
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// DEFAULT-NOT: llvm.type.test
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void f(S *s, void (S::*p)()) {
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// CHECK: [[OFFSET:%.*]] = sub i64 {{.*}}, 1
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// CHECK: [[VFPTR:%.*]] = getelementptr i8, i8* %{{.*}}, i64 [[OFFSET]]
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// CHECK: [[TT:%.*]] = call i1 @llvm.type.test(i8* [[VFPTR]], metadata !"_ZTSM1SFvvE.virtual")
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// CHECK: br i1 [[TT]], label {{.*}}, label %[[TRAP1:[^,]*]]
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// CHECK: [[TRAP1]]:
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// CHECK-NEXT: llvm.trap
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// CHECK: [[NVFPTR:%.*]] = bitcast void (%struct.S*)* {{.*}} to i8*
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// CHECK: [[TT1:%.*]] = call i1 @llvm.type.test(i8* [[NVFPTR]], metadata !"_ZTSM2B1FvvE")
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// CHECK: [[OR1:%.*]] = or i1 false, [[TT1]]
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// CHECK: [[TT2:%.*]] = call i1 @llvm.type.test(i8* [[NVFPTR]], metadata !"_ZTSM2B2FvvE")
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// CHECK: [[OR2:%.*]] = or i1 [[OR1]], [[TT2]]
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// CHECK: br i1 [[OR2]], label {{.*}}, label %[[TRAP2:[^,]*]]
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// CHECK: [[TRAP2]]:
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// CHECK-NEXT: llvm.trap
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(s->*p)();
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}
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