46f366494f
Currently we use RTTI objects to check type compatibility. To support non-unique RTTI objects, commit 5745eccef54ddd3caca278d1d292a88b2281528b added a `checkTypeInfoEquality` string matching to the runtime. The scheme is inefficient. ``` _Z1fv: .long 846595819 # jmp .long .L__llvm_rtti_proxy-_Z3funv ... main: ... # Load the second word (pointer to the RTTI object) and dereference it. movslq 4(%rsi), %rax movq (%rax,%rsi), %rdx # Is it the desired typeinfo object? leaq _ZTIFvvE(%rip), %rax # If not, call __ubsan_handle_function_type_mismatch_v1, which may recover if checkTypeInfoEquality allows cmpq %rax, %rdx jne .LBB1_2 ... .section .data.rel.ro,"aw",@progbits .p2align 3, 0x0 .L__llvm_rtti_proxy: .quad _ZTIFvvE ``` Let's replace the indirect `_ZTI` pointer with a type hash similar to `-fsanitize=kcfi`. ``` _Z1fv: .long 3238382334 .long 2772461324 # type hash main: ... # Load the second word (callee type hash) and check whether it is expected cmpl $-1522505972, -4(%rax) # If not, fail: call __ubsan_handle_function_type_mismatch jne .LBB2_2 ``` The RTTI object derives its name from `clang::MangleContext::mangleCXXRTTI`, which uses `mangleType`. `mangleTypeName` uses `mangleType` as well. So the type compatibility change is high-fidelity. Since we no longer need RTTI pointers in `__ubsan::__ubsan_handle_function_type_mismatch_v1`, let's switch it back to version 0, the original signature before e215996a2932ed7c472f4e94dc4345b30fd0c373 (2019). `__ubsan::__ubsan_handle_function_type_mismatch_abort` is not recoverable, so we can revert some changes from e215996a2932ed7c472f4e94dc4345b30fd0c373. Reviewed By: samitolvanen Differential Revision: https://reviews.llvm.org/D148785
19 lines
738 B
C++
19 lines
738 B
C++
// RUN: %clang_cc1 -std=c++17 -fsanitize=function -emit-llvm -triple x86_64-linux-gnu %s -o - | FileCheck %s
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/// Check the following two functions have the same func_sanitize metadata, i.e.
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/// they have the same type hash despite the exception specifier.
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// CHECK: define{{.*}} void @_Z1fv() #[[#]] !func_sanitize ![[FUNCSAN:.*]] {
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// CHECK: define{{.*}} void @_Z10f_noexceptv() #[[#]] !func_sanitize
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// CHECK-SAME: ![[FUNCSAN]] {
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void f() {}
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void f_noexcept() noexcept {}
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// CHECK: define{{.*}} void @_Z1gPDoFvvE
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void g(void (*p)() noexcept) {
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// CHECK: icmp eq i32 %{{.*}}, -1056584962, !nosanitize
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// CHECK: icmp eq i32 %{{.*}}, [[Hash:[-0-9]+]], !nosanitize
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p();
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}
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// CHECK: ![[FUNCSAN]] = !{i32 -1056584962, i32 [[Hash]]}
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