clang-tidy google-build-using-namespace check and std::.*literals

Martin · February 12, 2016, 5:10pm

Hello,

(I am not subscribed to cfe-dev so please keep me in CC.)

I would like to get some feedback on
https://llvm.org/bugs/show_bug.cgi?id=25594 . Patch here:
https://llvm.org/bugs/attachment.cgi?id=15324 .

More specifically, why does my matcher modification not make it so
that the check skips std::.*literals namespaces? Have I misunderstood
what regular expression dialect is used in LLVM? Am I not using the
matcher correctly?

When writing the patch I tried to see how matchers are used in other
places and also tried to verify the regexp dialect. If I remember
correctly, I could not find any documentation for this though. Or, at
least any documentation or uses of matchers in other places of the
code that indicated to me that this should not work.

Also, is this patch something that is wanted? As far as I know there
is no way to use the standard defined literals without "using".

Thanks!

Nikola_Smiljanic · February 14, 2016, 10:48pm

Could it be the leading :: in your regex?

Martin · February 15, 2016, 6:17pm

Hello Nikola,

Could it be the leading :: in your regex?

I do not think so. The SizeofContainerCheck, for instance, does
something similar:

github.com

llvm-mirror/clang-tools-extra/blob/61bf08cac6860dfd33287ee756dcb7453f14a4e4/clang-tidy/misc/SizeofContainerCheck.cpp#L25


      
          
          namespace clang {
          namespace tidy {
          
          void SizeofContainerCheck::registerMatchers(MatchFinder *Finder) {
            Finder->addMatcher(
                expr(unless(isInTemplateInstantiation()),
                     expr(sizeOfExpr(has(
                              expr(hasType(hasCanonicalType(hasDeclaration(cxxRecordDecl(
                                  matchesName("^(::std::|::string)"),
                                  unless(matchesName("^::std::(bitset|array)$")),
                                  hasMethod(cxxMethodDecl(hasName("size"), isPublic(),
                                                          isConst()))))))))))
                         .bind("sizeof"),
                     // Ignore ARRAYSIZE(<array of containers>) pattern.
                     unless(hasAncestor(binaryOperator(
                         anyOf(hasOperatorName("/"), hasOperatorName("%")),
                         hasLHS(ignoringParenCasts(sizeOfExpr(expr()))),
                         hasRHS(ignoringParenCasts(equalsBoundNode("sizeof"))))))),
                this);
          }

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clang-tidy google-build-using-namespace check and std::.*literals

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