[lldb-dev] Was this an unintended consequence of the Args switch to StringRef's?

Jim Ingham via lldb-dev lldb-dev at lists.llvm.org
Wed Apr 5 16:10:05 PDT 2017


I think somebody was being too clever.  The real purpose for specifying the format is to set the byte size of the item written down:

    OptionValueUInt64 &byte_size_value = m_format_options.GetByteSizeValue();
    size_t item_byte_size = byte_size_value.GetCurrentValue();

and to do some special magic for c-strings and the like.  Somebody (not me) must have thought overloading "hex" format to mean "you can drop the 0x" was a tasty little side benefit.

But it's been that way forever, and I don't know who's relying on that behavior, so I'd rather not change it (intentionally) if we don't have to.


> On Wed, Apr 5, 2017 at 3:37 PM Jim Ingham via lldb-dev <lldb-dev at lists.llvm.org> wrote:
> memory write's argument ingestion was changed as part of the StringRefifying of Args so that we get:
> (lldb) memory write &buffer 0x62
> error: '0x62' is not a valid hex string value.
> That seems unexpected and not desirable.  What's going on is that the default format is hex, and if the format is hex, the command also supports:
> (lldb) memory write -f x &buffer 62
> (lldb) fr v/x buffer[0]
> (char) buffer[0] = 0x62
> The StringRef version of the args parsing is:
>       case eFormatDefault:
>       case eFormatBytes:
>       case eFormatHex:
>       case eFormatHexUppercase:
>       case eFormatPointer:
>         // Decode hex bytes
>         if (entry.ref.getAsInteger(16, uval64)) {
> The problem is that passing "0x62" to getAsInteger with a radix of 16 rejects "0x62".
> We do want to hint the radix.  But it seems weird to reject an explicit indicator.  Is there some clever way to use the StringRef functions to get the desired effect, or do I have to hack around this by manually stripping the 0x if I see it?
> Jim
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