aeubanks added inline comments.
================ Comment at: clang/lib/Sema/SemaExpr.cpp:3586-3591 + // MSVC treats all predefined expressions as string literals rather than char + // arrays. + if (LangOpts.MicrosoftExt) + return SL; + return PredefinedExpr::Create(Context, Loc, ResTy, IK, SL); ---------------- cor3ntin wrote: > aaron.ballman wrote: > > aeubanks wrote: > > > aaron.ballman wrote: > > > > This is incorrect -- these are still predefined expressions even if > > > > they're a string literal. Otherwise, we lose AST fidelity and things > > > > like the `predefinedExpr()` AST matcher don't work > > > > (https://github.com/llvm/llvm-project/blob/main/clang/include/clang/ASTMatchers/ASTMatchers.h#L2697), > > > > and `-ast-print` will print the wrong thing > > > > (https://github.com/llvm/llvm-project/blob/main/clang/lib/AST/StmtPrinter.cpp#L1248). > > > how would you structure this? an almost identical `PredefinedExpr` class > > > that also subclasses `StringLiteral`? or special case all the places that > > > check for `StringLiteral` to also check for `PredefinedExpr` (the case I > > > was mostly looking at was initializing a char array with predefined > > > expressions but presumably there are more places that matter) > > We can't inherit from `StringLiteral` (it's a `final` class because it has > > `TrailingObjects`), so that might be the only viable approach. However, > > there's a fair number of places in the compiler where we care if something > > is or isn't a `StringLiteral`, so I can see why we'd want to avoid that if > > possible. > > > > Oye, but it seems that even MSVC is not consistent with whether the > > predefined expression is a string literal or not: > > https://godbolt.org/z/jzY8cz79d > I think these should be plain old string literals, but for the purpose or AST > matchers and such, maybe we could have a "predefined macro" bit, or even an > additional object that stores the name. > Oye, but it seems that even MSVC is not consistent with whether the > predefined expression is a string literal or not: > https://godbolt.org/z/jzY8cz79d the other predefined expressions work, that looks like a bug on MSVC's part > I think these should be plain old string literals, but for the purpose or AST > matchers and such, maybe we could have a "predefined macro" bit, or even an > additional object that stores the name. what do you mean by "an additional object that stores the name"? I started trying to add a bit to `StringLiteral` that signifies if it's an MSVC predefined expression. being new to ast matchers, I'm having trouble figuring out how to make a matcher that matches both `PredefinedExpr` and some `StringLiteral`s but also behaves like a `VariadicDynCastAllOfMatcher`. something I noticed in one of the tests [1] is that there's a check ``` predefinedExpr(hasType(asString("const char[4]")), has(stringLiteral())) ``` thinking about the `has(stringLiteral())`, if somebody wants to get the literal for a predefined expr, presumably right now they're looking for a string literal child, but if we directly match a string literal then that would break? WDYT? [1] https://github.com/llvm/llvm-project/blob/75ca15fcbb2e1b3671e41f971a000c6d59f5e5ae/clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp#L1064 Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D146764/new/ https://reviews.llvm.org/D146764 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
