[cfe-dev] [ASTImporter][CrossTU] inconsistent enumerators
Rafael·Stahl via cfe-dev
cfe-dev at lists.llvm.org
Mon Dec 4 08:57:34 PST 2017
Hello Aleksei,
Thank you for looking into this.
Find attached a project of the files I mentioned in my initial report.
If you check out something like r318000 and apply the current CTU patch
( https://reviews.llvm.org/D30691 Diff11 is current as of writing), the
issue should be visible.
@Gábor Since I run the analyzer from a custom library: Can you tell
Aleksei how to run scan-build on the project? As far as I understand it
should be possible with the current patch, right?
Regards
Rafael
On 03/12/17 19:22, Aleksei Sidorin wrote:
> Hello guys,
>
> Do you have a reprocase I can just launch clang against? I have some
> ideas but ASTMerge and clang-import-test infrastructures are not very
> suitable for testing CSA XTU import strategy.
>
>
> 16.11.2017 19:42, Gábor Horváth via cfe-dev пишет:
>> Hi Rafael!
>>
>> Yeah, the cross TU patch is a great way to detect issues with the
>> ASTImporter and unfortunately, those issues are extremely hard to debug.
>>
>> Here, it looks like the source of the problem is that, when we import
>> an EnumConstantDecl, we will import the EnumDecl without the typdef part.
>> A dirty quick fix for this particular case:
>>
>> @@ -1782,6 +1807,11 @@ Decl
>> *ASTNodeImporter::VisitEnumConstantDecl(EnumConstantDecl *D) {
>> DeclarationName Name;
>> SourceLocation Loc;
>> NamedDecl *ToD;
>> + auto *ED = cast<EnumDecl>(D->getDeclContext());
>> + if (auto *TND = ED->getTypedefNameForAnonDecl()) {
>> + if (!Importer.Import(TND))
>> + return nullptr;
>> + }
>> if (ImportDeclParts(D, DC, LexicalDC, Name, ToD, Loc))
>> return nullptr;
>> if (ToD)
>>
>> I did not have time yet to deep dive into this and look at what the
>> proper solution would be. Are you willing to continue to investigate
>> this?
>>
>> Regards,
>> Gábor
>>
>> On 13 November 2017 at 12:16, Rafael·Stahl via cfe-dev
>> <cfe-dev at lists.llvm.org <mailto:cfe-dev at lists.llvm.org>> wrote:
>>
>> Deal all
>>
>> While using the static analyzer with cross translation unit
>> support ( https://reviews.llvm.org/D30691
>> <https://reviews.llvm.org/D30691> ), I stumbled upon an issue
>> that is most likely related to the ASTImporter.
>>
>> I'm using a custom checker, but this should be reproduced by just
>> running the scan-build tool.
>>
>> A simple reproducing example:
>>
>> main.c:
>>
>> ---------------------------------------
>> void foo();
>> void moo();
>>
>> int main()
>> {
>> foo();
>> moo();
>> }
>> ---------------------------------------
>>
>> foo.c:
>>
>> ---------------------------------------
>> #include "thing.h"
>>
>> void foo()
>> {
>> (void)THING_VALUE;
>> }
>>
>> void conflict(thing_t type)
>> {
>> }
>> ---------------------------------------
>>
>> moo.c:
>>
>> ---------------------------------------
>> #include "thing.h"
>>
>> void moo()
>> {
>> conflict(THING_VALUE);
>> }
>> ---------------------------------------
>>
>> thing.h:
>>
>> ---------------------------------------
>> typedef enum {
>> THING_VALUE
>> } thing_t;
>>
>> void conflict(thing_t type);
>> ---------------------------------------
>>
>> Notes on particularities of this example:
>>
>> - main.c needs to NOT include the header
>> - main() needs to call the functions in this order
>> - foo() needs to reference the enumerator
>> - the enum needs to be typedef'd
>>
>> If any of the above points do not apply, the issue does not appear.
>>
>> The issue:
>>
>> ---------------------------------------
>> In file included from moo.c:1:
>> thing.h:1:9: warning: type 'thing_t' has incompatible
>> definitions in different translation units [-Wodr]
>> typedef enum {
>> ^
>> thing.h:2:5: note: enumerator 'THING_VALUE' with value 0 here
>> THING_VALUE
>> ^
>> thing.h:1:9: note: no corresponding enumerator here
>> foo.c:8:6: error: external function 'conflict' declared
>> with incompatible types in different translation units
>> ('void (thing_t)' vs. 'void (thing_t)')
>> void conflict(thing_t type)
>> ^
>> thing.h:5:6: note: declared here with type
>> 'void (thing_t)'
>> void conflict(thing_t type);
>> ^
>> ---------------------------------------
>>
>> After importing conflict(thing_t) the ASTImporter compared the
>> imported one with the original by structural equivalence. This
>> reveals that in the imported enum the enumerators are missing,
>> causing the above error.
>>
>> In my real code, not this example, I was unable to dump the
>> imported EnumDecl, because it eventually calls
>> SourceManager::isBeforeInTranslationUnit with two SourceLocations
>> from different files. Not sure if this is related.
>>
>> I have tried adding:
>>
>> for (const auto Enumerator : D->enumerators())
>> D2->addDecl(Importer.Import(Enumerator));
>>
>> before completing the definition in
>> ASTNodeImporter::VisitEnumDecl(), but that results in:
>>
>> exe: tools/clang/lib/AST/DeclBase.cpp:1374: void
>> clang::DeclContext::addHiddenDecl(clang::Decl*): Assertion
>> `!D->getNextDeclInContext() && D != LastDecl && "Decl already
>> inserted into a DeclContext"' failed.
>>
>> I'm not familiar enough with the ASTImporter to help myself
>> further here. Does anyone know what could be the issue?
>>
>> Best regards
>> Rafael Stahl
>>
>>
>>
>> _______________________________________________
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>>
>>
>>
>>
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>
>
> --
> Best regards,
> Aleksei Sidorin,
> SRR, Samsung Electronics
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