Author: Timm Baeder Date: 2025-04-23T18:52:35+02:00 New Revision: 1b6cbaa7b64f54b127d139d653468e213bae007e
URL: https://github.com/llvm/llvm-project/commit/1b6cbaa7b64f54b127d139d653468e213bae007e DIFF: https://github.com/llvm/llvm-project/commit/1b6cbaa7b64f54b127d139d653468e213bae007e.diff LOG: [clang][bytecode] Refine diagnostics for volatile reads (#136857) Differentiate between a volarile read via a lvalue-to-rvalue cast of a volatile qualified subexpression and a read from a pointer with a volatile base object. Added: Modified: clang/lib/AST/ByteCode/Compiler.cpp clang/lib/AST/ByteCode/Interp.cpp clang/lib/AST/ByteCode/Interp.h clang/lib/AST/ByteCode/PrimType.h clang/test/AST/ByteCode/literals.cpp Removed: ################################################################################ diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp index 7cba0e8a4da19..65d87cdff6ad2 100644 --- a/clang/lib/AST/ByteCode/Compiler.cpp +++ b/clang/lib/AST/ByteCode/Compiler.cpp @@ -210,6 +210,9 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) { switch (CE->getCastKind()) { case CK_LValueToRValue: { + if (SubExpr->getType().isVolatileQualified()) + return this->emitInvalidCast(CastKind::Volatile, /*Fatal=*/true, CE); + std::optional<PrimType> SubExprT = classify(SubExpr->getType()); // Prepare storage for the result. if (!Initializing && !SubExprT) { diff --git a/clang/lib/AST/ByteCode/Interp.cpp b/clang/lib/AST/ByteCode/Interp.cpp index b755a072fec88..6f277a7488836 100644 --- a/clang/lib/AST/ByteCode/Interp.cpp +++ b/clang/lib/AST/ByteCode/Interp.cpp @@ -641,11 +641,30 @@ static bool CheckVolatile(InterpState &S, CodePtr OpPC, const Pointer &Ptr, if (!PtrType.isVolatileQualified()) return true; - const SourceInfo &Loc = S.Current->getSource(OpPC); - if (S.getLangOpts().CPlusPlus) - S.FFDiag(Loc, diag::note_constexpr_access_volatile_type) << AK << PtrType; - else - S.FFDiag(Loc); + if (!S.getLangOpts().CPlusPlus) + return Invalid(S, OpPC); + + const NamedDecl *ND = nullptr; + int DiagKind; + SourceLocation Loc; + if (const auto *F = Ptr.getField()) { + DiagKind = 2; + Loc = F->getLocation(); + ND = F; + } else if (auto *VD = Ptr.getFieldDesc()->asValueDecl()) { + DiagKind = 1; + Loc = VD->getLocation(); + ND = VD; + } else { + DiagKind = 0; + if (const auto *E = Ptr.getFieldDesc()->asExpr()) + Loc = E->getExprLoc(); + } + + S.FFDiag(S.Current->getLocation(OpPC), + diag::note_constexpr_access_volatile_obj, 1) + << AK << DiagKind << ND; + S.Note(Loc, diag::note_constexpr_volatile_here) << DiagKind; return false; } diff --git a/clang/lib/AST/ByteCode/Interp.h b/clang/lib/AST/ByteCode/Interp.h index e5300b7cd96a9..588e0502fa88c 100644 --- a/clang/lib/AST/ByteCode/Interp.h +++ b/clang/lib/AST/ByteCode/Interp.h @@ -2885,12 +2885,22 @@ inline bool InvalidCast(InterpState &S, CodePtr OpPC, CastKind Kind, bool Fatal) { const SourceLocation &Loc = S.Current->getLocation(OpPC); - // FIXME: Support diagnosing other invalid cast kinds. if (Kind == CastKind::Reinterpret) { S.CCEDiag(Loc, diag::note_constexpr_invalid_cast) << static_cast<unsigned>(Kind) << S.Current->getRange(OpPC); return !Fatal; + } else if (Kind == CastKind::Volatile) { + // FIXME: Technically not a cast. + const auto *E = cast<CastExpr>(S.Current->getExpr(OpPC)); + if (S.getLangOpts().CPlusPlus) + S.FFDiag(E, diag::note_constexpr_access_volatile_type) + << AK_Read << E->getSubExpr()->getType(); + else + S.FFDiag(E); + + return false; } + return false; } diff --git a/clang/lib/AST/ByteCode/PrimType.h b/clang/lib/AST/ByteCode/PrimType.h index a3c0b0f3ceca8..c6145d4823a0c 100644 --- a/clang/lib/AST/ByteCode/PrimType.h +++ b/clang/lib/AST/ByteCode/PrimType.h @@ -55,16 +55,17 @@ inline constexpr bool isPtrType(PrimType T) { enum class CastKind : uint8_t { Reinterpret, - Atomic, + Volatile, }; + inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, interp::CastKind CK) { switch (CK) { case interp::CastKind::Reinterpret: OS << "reinterpret_cast"; break; - case interp::CastKind::Atomic: - OS << "atomic"; + case interp::CastKind::Volatile: + OS << "volatile"; break; } return OS; diff --git a/clang/test/AST/ByteCode/literals.cpp b/clang/test/AST/ByteCode/literals.cpp index 6b33c5cc22367..c36289db6e85c 100644 --- a/clang/test/AST/ByteCode/literals.cpp +++ b/clang/test/AST/ByteCode/literals.cpp @@ -1357,6 +1357,22 @@ namespace VolatileReads { const volatile int b = 1; static_assert(b, ""); // both-error {{not an integral constant expression}} \ // both-note {{read of volatile-qualified type 'const volatile int' is not allowed in a constant expression}} + + + constexpr int a = 12; + constexpr volatile int c = (volatile int&)a; // both-error {{must be initialized by a constant expression}} \ + // both-note {{read of volatile-qualified type 'volatile int'}} + + volatile constexpr int n1 = 0; // both-note {{here}} + volatile const int n2 = 0; // both-note {{here}} + constexpr int m1 = n1; // both-error {{constant expression}} \ + // both-note {{read of volatile-qualified type 'const volatile int'}} + constexpr int m2 = n2; // both-error {{constant expression}} \ + // both-note {{read of volatile-qualified type 'const volatile int'}} + constexpr int m1b = const_cast<const int&>(n1); // both-error {{constant expression}} \ + // both-note {{read of volatile object 'n1'}} + constexpr int m2b = const_cast<const int&>(n2); // both-error {{constant expression}} \ + // both-note {{read of volatile object 'n2'}} } #if __cplusplus >= 201703L namespace { _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
