alexfh added inline comments.
================
Comment at: clang-tools-extra/trunk/clangd/index/Index.h:71
+ // via llvm::StringRef.
+ const char *FileURI = "";
};
----------------
hokein wrote:
> alexfh wrote:
> > If the users of the SymbolLocation have a way to get a common "context",
> > you could keep a list of filenames in this context and just store an index
> > into this list (which could be even shorter). If the structure is used
> > where no context is available, you could still keep a list of StringRefs
> > somewhere (probably close to where the string data pointed by the
> > StringRefs lives) and keep a `StringRef *` here. At a cost of one
> > indirection you'd avoid calling strlen.
> >
> > Not sure what trade-off is better for this particular use case though.
> `SymbolLocation` is a public interface, and the underlying data is stored in
> arena (which is not visible to clients), so clients don't know any `Context`
> except `SymbolLocation`.
>
> Using `StringRef *` is an interesting idea -- keeping a list of `StringRefs`
> needs extra space, the number should be relatively small (only the number of
> different files), so we will spend extra `<num of files> *
> sizeof(StringRef)` bytes (for llvm, ~128 KB memory) , compared with the raw
> pointer solution.
Another option mentioned by Ilya offline is similar to MS's BSTR: keep the
length along with the string data in the arena. Something like:
```
class InlineString {
size_t Length;
char Data[0]; // Open-ended array with a null-terminated string in it.
public:
operator StringRef() const { return StringRef(&Data[0], Length); }
...
};
```
And then keep `const InlineString *` here.
Repository:
rL LLVM
https://reviews.llvm.org/D53427
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