peter.smith added a comment.
Should `HANDLER(__ubsan_handle_function_type_mismatch,"function")` be added to
ubsan_minimal_runtime if this is supported in the minimal runtime?
================
Comment at: clang/lib/CodeGen/CGExpr.cpp:5382
+ getPointerAlign());
llvm::Value *CalleeRTTIMatch =
+ Builder.CreateICmpEQ(CalleeTypeHash, TypeHash);
----------------
Would CalleeTypeHashMatch be a better name?
================
Comment at: clang/lib/CodeGen/CodeGenFunction.h:120
SANITIZER_CHECK(FloatCastOverflow, float_cast_overflow, 0)
\
- SANITIZER_CHECK(FunctionTypeMismatch, function_type_mismatch, 1)
\
+ SANITIZER_CHECK(FunctionTypeMismatch, function_type_mismatch, 0)
\
SANITIZER_CHECK(ImplicitConversion, implicit_conversion, 0)
\
----------------
Presumably the signature is different to the original v0 shouldn't it be 2; or
is it effectively so long since the last one that we can reuse the original
without fear?
================
Comment at: clang/test/CodeGenCXX/catch-undef-behavior.cpp:408
// RTTI pointer check
+ // CHECK: [[CalleeTypeHashPtr:%.+]] = getelementptr <{ i32, i32 }>, <{ i32,
i32 }>* [[PTR]], i32 -1, i32 1
----------------
CalleeTypeHash check?
================
Comment at: llvm/test/CodeGen/AArch64/patchable-function-entry-bti.ll:92
; CHECK-NEXT: .Ltmp{{.*}}:
; CHECK-NEXT: nop
; CHECK-NEXT: .word 3238382334 // 0xc105cafe
----------------
Assuming the test is the equivalent of `-fpatchable-function-entry=1,1` I think
this is the wrong place for the nop, I think it needs to be after the signature
and the loads adjusted. For example with -fsanitize=kcfi
-fpatchable-function-entries=1,1
```
typedef int Fptr(void);
int function(void) {
return 0;
}
int call(Fptr* fp) {
return fp();
}
```
Results in code like:
```
.word 1670944012 // @call
// 0x6398950c
.Ltmp1:
nop
call:
.Lfunc_begin1:
.cfi_startproc
// %bb.0: // %entry
ldur w16, [x0, #-8]
movk w17, #50598
movk w17, #14001, lsl #16
cmp w16, w17
b.eq .Ltmp2
brk #0x8220
.Ltmp2:
br x0
.Lfunc_end1:
```
Note the NOP is after the signature, with the `ldur` having an offset of -8 and
not the usual -4. I think you would need to make sure the signature is a branch
instruction for each target for this scheme to work.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D148785/new/
https://reviews.llvm.org/D148785
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