MaskRay added inline comments.
================
Comment at: llvm/lib/Demangle/Demangle.cpp:49
bool llvm::nonMicrosoftDemangle(const char *MangledName, std::string &Result) {
+ if (!MangledName)
+ return false;
----------------
nickdesaulniers wrote:
> nickdesaulniers wrote:
> > MaskRay wrote:
> > > Why is this change? The original contract is that `MangledName` must be
> > > non-null.
> > https://fosstodon.org/@llvm/110397650834821908
> >
> > It's insidious; implicitly constructing a `std::string_view` from a `char*`
> > which is `nullptr` invokes a call to `strlen` upon construction, which
> > segfaults on my system. Therefor, all of the `nullptr` checks need to be
> > hoisted into the callers or stated another way exist at the boundary of
> > `char*` to `std::string_view` API boundaries (such as right here).
> This is also why the `nullptr` input test case must be removed from
> llvm/unittests/Demangle/DLangDemangleTest.cpp below.
It's usually code smell if a function taking a C string argument additionally
accepts nullptr.
Previously, passing `nullptr` to `nonMicrosoftDemangle` will crash as
`MangledName[0]` is accessed. We should retain this strictness.
`ninja check-llvm-demangle` passes if I remove the 2 lines.
If future refactoring will possibly pass `nullptr` to `nonMicrosoftDemangle`, I
think we should fix those call sites not to do that...
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D151003/new/
https://reviews.llvm.org/D151003
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