[PATCH] D27634: Make a DWARFDIE class that can help avoid using the wrong DWARFUnit when extracting attributes
Adrian Prantl via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 9 15:45:14 PST 2016
> On Dec 9, 2016, at 3:26 PM, Greg Clayton via Phabricator <reviews at reviews.llvm.org> wrote:
>
> clayborg added a comment.
>
> Commented a bit with fixes coming soon.
>
>
>
> ================
> Comment at: include/llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h:29
>
> -/// DWARFDebugInfoEntryMinimal - A DIE with only the minimum required data.
> -class DWARFDebugInfoEntryMinimal {
> +/// DWARFDebugInfoEntry - A DIE with only the minimum required data.
> +class DWARFDebugInfoEntry {
> ----------------
> aprantl wrote:
>> Is this comment still accurate?
> Yes it is still accurate.
>
>
> ================
> Comment at: include/llvm/DebugInfo/DWARF/DWARFDie.h:61
> + return Die->getOffset();
> + return -1U;
> + }
> ----------------
> aprantl wrote:
>> Optional<uint32_t> ?
>> Optional<DwarfOffset>, to allow 64-bit?
> These are wrapping the APIs that used to be in DWARFDebugInfoEntryMinimal for now. I will add Optional support to all values in a follow up patch.
Great! Splitting the migration to Optional<> out into separate change is a good idea, since it will change all the call sites.
>
>
> ================
> Comment at: include/llvm/DebugInfo/DWARF/DWARFDie.h:71
> +
> + bool hasChildren() const {
> + if (Die)
> ----------------
> Many APIs can give you back an DWARFDie object that don't contain a DWARFUnit or DWARFDie so it does make sense to answer as correctly as possible
>
>
> ================
> Comment at: include/llvm/DebugInfo/DWARF/DWARFDie.h:77
> +
> + bool isNULL() const {
> + return getAbbreviationDeclarationPtr() == nullptr;
> ----------------
> aprantl wrote:
>> operator bool() const?
>> Oh, or does this mean the NULL DIE that is at the end of each group?
> This means valid but NULL Die. I should actually change this do be:
>
> ```
> return Die != nullptr && getAbbreviationDeclarationPtr() == nullptr;
> ```
>
> Because isNULL should only be true if we have a valid DWARFDebugInfoEntry, yet it has an abbrev code of zero
>
>
> ================
> Comment at: include/llvm/DebugInfo/DWARF/DWARFDie.h:91
> + /// invalid DWARFDie instance if it doesn't.
> + DWARFDie getSibling() const {
> + if (isValid())
> ----------------
> aprantl wrote:
>> Perhaps Optional instead of default-construction?
> Good idea.I'll do that in a follow up change once this is in.
>
>
> ================
> Comment at: include/llvm/DebugInfo/DWARF/DWARFDie.h:124-125
> + /// \returns true if the attribute was extracted from this DIE.
> + bool getAttributeValue(dwarf::Attribute Attr,
> + DWARFFormValue &FormValue) const;
> +
> ----------------
> Let me do this in a follow up change otherwise this will introduce a ton of churn in this change. Is that ok?
Absolutely. All the API changes can/should ideally be separate follow-up commits.
thanks,
adrian
>
>
> ================
> Comment at: lib/DebugInfo/DWARF/DWARFContext.cpp:159-160
> savedAddressByteSize = CU->getAddressByteSize();
> - const auto *CUDIE = CU->getUnitDIE();
> - if (CUDIE == nullptr)
> + auto CUDIE = CU->getUnitDIE();
> + if (!CUDIE)
> continue;
> ----------------
> It isn't a pointer anymore, it is an object. So this does go along with this change. It is invoking the operator bool on DWARFDie.
>
>
> https://reviews.llvm.org/D27634
>
>
>
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