diff --git a/docs/LanguageExtensions.rst b/docs/LanguageExtensions.rst index 64e6ffb7f3eb..885ad579ba72 100644 --- a/docs/LanguageExtensions.rst +++ b/docs/LanguageExtensions.rst @@ -1776,6 +1776,46 @@ numeric primitives such as frexp. See `LLVM canonicalize intrinsic `_ for more information on the semantics. +String builtins +--------------- + +Clang provides constant expression evaluation support for builtins forms of +the following functions from the C standard library ```` header: + +* ``memchr`` +* ``memcmp`` +* ``strchr`` +* ``strcmp`` +* ``strlen`` +* ``strncmp`` +* ``wcschr`` +* ``wcscmp`` +* ``wcslen`` +* ``wcsncmp`` +* ``wmemchr`` +* ``wmemcmp`` + +In each case, the builtin form has the name of the C library function prefixed +by ``__builtin_``. Example: + +.. code-block:: c + + void *p = __builtin_memchr("foobar", 'b', 5); + +In addition to the above, one further builtin is provided: + +.. code-block:: c + + char *__builtin_char_memchr(const char *haystack, int needle, size_t size); + +``__builtin_char_memchr(a, b, c)`` is identical to +``(char*)__builtin_memchr(a, b, c)`` except that its use is permitted within +constant expressions in C++11 onwards (where a cast from ``void*`` to ``char*`` +is disallowed in general). + +Support for constant expression evaluation for the above builtins be detected +with ``__has_feature(cxx_constexpr_string_builtins)``. + .. _langext-__c11_atomic: __c11_atomic builtins diff --git a/include/clang/Basic/Builtins.def b/include/clang/Basic/Builtins.def index ec0a2796ec08..326a8fa66360 100644 --- a/include/clang/Basic/Builtins.def +++ b/include/clang/Basic/Builtins.def @@ -1339,6 +1339,7 @@ BUILTIN(__builtin_smulll_overflow, "bSLLiCSLLiCSLLi*", "n") BUILTIN(__builtin_addressof, "v*v&", "nct") BUILTIN(__builtin_operator_new, "v*z", "c") BUILTIN(__builtin_operator_delete, "vv*", "n") +BUILTIN(__builtin_char_memchr, "c*cC*iz", "n") // Safestack builtins BUILTIN(__builtin___get_unsafe_stack_start, "v*", "Fn") diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp index a8512b294055..5fab58a5af95 100644 --- a/lib/AST/ExprConstant.cpp +++ b/lib/AST/ExprConstant.cpp @@ -5683,6 +5683,7 @@ bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, case Builtin::BI__builtin_strchr: case Builtin::BI__builtin_wcschr: case Builtin::BI__builtin_memchr: + case Builtin::BI__builtin_char_memchr: case Builtin::BI__builtin_wmemchr: { if (!Visit(E->getArg(0))) return false; @@ -5720,6 +5721,7 @@ bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, // Fall through. case Builtin::BImemchr: case Builtin::BI__builtin_memchr: + case Builtin::BI__builtin_char_memchr: // memchr compares by converting both sides to unsigned char. That's also // correct for strchr if we get this far (to cope with plain char being // unsigned in the strchr case). diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp index 2ede1d46b3d5..b3d02f1f51c6 100644 --- a/lib/CodeGen/CGBuiltin.cpp +++ b/lib/CodeGen/CGBuiltin.cpp @@ -1189,6 +1189,10 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD, return RValue::get(Dest.getPointer()); } + case Builtin::BI__builtin_char_memchr: + BuiltinID = Builtin::BI__builtin_memchr; + break; + case Builtin::BI__builtin___memcpy_chk: { // fold __builtin_memcpy_chk(x, y, cst1, cst2) to memcpy iff cst1<=cst2. llvm::APSInt Size, DstSize; diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp index aebebaac46ac..de166c75e2cb 100644 --- a/lib/Lex/PPMacroExpansion.cpp +++ b/lib/Lex/PPMacroExpansion.cpp @@ -1183,6 +1183,7 @@ static bool HasFeature(const Preprocessor &PP, StringRef Feature) { .Case("cxx_attributes", LangOpts.CPlusPlus11) .Case("cxx_auto_type", LangOpts.CPlusPlus11) .Case("cxx_constexpr", LangOpts.CPlusPlus11) + .Case("cxx_constexpr_string_builtins", LangOpts.CPlusPlus11) .Case("cxx_decltype", LangOpts.CPlusPlus11) .Case("cxx_decltype_incomplete_return_types", LangOpts.CPlusPlus11) .Case("cxx_default_function_template_args", LangOpts.CPlusPlus11) diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp index a70e16cce18c..f265f4c00f71 100644 --- a/lib/Sema/SemaDeclCXX.cpp +++ b/lib/Sema/SemaDeclCXX.cpp @@ -12383,9 +12383,9 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field) { Diag(Loc, diag::err_in_class_initializer_not_yet_parsed) << OutermostClass << Field; Diag(Field->getLocEnd(), diag::note_in_class_initializer_not_yet_parsed); - - // Don't diagnose this again. - Field->setInvalidDecl(); + // Recover by marking the field invalid, unless we're in a SFINAE context. + if (!isSFINAEContext()) + Field->setInvalidDecl(); return ExprError(); } diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp index d62e8fd68b64..e1e1f0283629 100644 --- a/lib/Sema/SemaExpr.cpp +++ b/lib/Sema/SemaExpr.cpp @@ -11496,7 +11496,7 @@ ExprResult Sema::BuildBinOp(Scope *S, SourceLocation OpLoc, return checkPseudoObjectAssignment(S, OpLoc, Opc, LHSExpr, RHSExpr); // Don't resolve overloads if the other type is overloadable. - if (pty->getKind() == BuiltinType::Overload) { + if (getLangOpts().CPlusPlus && pty->getKind() == BuiltinType::Overload) { // We can't actually test that if we still have a placeholder, // though. Fortunately, none of the exceptions we see in that // code below are valid when the LHS is an overload set. Note @@ -11521,17 +11521,16 @@ ExprResult Sema::BuildBinOp(Scope *S, SourceLocation OpLoc, // An overload in the RHS can potentially be resolved by the type // being assigned to. if (Opc == BO_Assign && pty->getKind() == BuiltinType::Overload) { - if (LHSExpr->isTypeDependent() || RHSExpr->isTypeDependent()) - return BuildOverloadedBinOp(*this, S, OpLoc, Opc, LHSExpr, RHSExpr); - - if (LHSExpr->getType()->isOverloadableType()) + if (getLangOpts().CPlusPlus && + (LHSExpr->isTypeDependent() || RHSExpr->isTypeDependent() || + LHSExpr->getType()->isOverloadableType())) return BuildOverloadedBinOp(*this, S, OpLoc, Opc, LHSExpr, RHSExpr); return CreateBuiltinBinOp(OpLoc, Opc, LHSExpr, RHSExpr); } // Don't resolve overloads if the other type is overloadable. - if (pty->getKind() == BuiltinType::Overload && + if (getLangOpts().CPlusPlus && pty->getKind() == BuiltinType::Overload && LHSExpr->getType()->isOverloadableType()) return BuildOverloadedBinOp(*this, S, OpLoc, Opc, LHSExpr, RHSExpr); diff --git a/test/CodeGenCXX/builtins.cpp b/test/CodeGenCXX/builtins.cpp index 98e2d1a8271c..a49deea2524c 100644 --- a/test/CodeGenCXX/builtins.cpp +++ b/test/CodeGenCXX/builtins.cpp @@ -26,3 +26,7 @@ int x = __builtin_abs(-2); long y = __builtin_abs(-2l); // CHECK: [[Y:%.+]] = call i64 @_Z13__builtin_absl(i64 -2) // CHECK: store i64 [[Y]], i64* @y, align 8 + +extern const char char_memchr_arg[32]; +char *memchr_result = __builtin_char_memchr(char_memchr_arg, 123, 32); +// CHECK: call i8* @memchr(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @char_memchr_arg, i32 0, i32 0), i32 123, i64 32) diff --git a/test/Lexer/has_feature_cxx0x.cpp b/test/Lexer/has_feature_cxx0x.cpp index 8c7ff18860a2..9082ca848c69 100644 --- a/test/Lexer/has_feature_cxx0x.cpp +++ b/test/Lexer/has_feature_cxx0x.cpp @@ -301,6 +301,17 @@ int no_constexpr(); // CHECK-11: has_constexpr // CHECK-NO-11: no_constexpr +#if __has_feature(cxx_constexpr_string_builtins) +int has_constexpr_string_builtins(); +#else +int no_constexpr_string_builtins(); +#endif + +// CHECK-1Z: has_constexpr_string_builtins +// CHECK-14: has_constexpr_string_builtins +// CHECK-11: has_constexpr_string_builtins +// CHECK-NO-11: no_constexpr_string_builtins + #if __has_feature(cxx_generalized_initializers) int has_generalized_initializers(); #else diff --git a/test/Sema/PR28181.c b/test/Sema/PR28181.c new file mode 100644 index 000000000000..3410f466fc73 --- /dev/null +++ b/test/Sema/PR28181.c @@ -0,0 +1,13 @@ +// RUN: %clang_cc1 -fsyntax-only -verify %s + +struct spinlock_t { + int lock; +} audit_skb_queue; + +void fn1() { + audit_skb_queue = (lock); // expected-error {{use of undeclared identifier 'lock'; did you mean 'long'?}} +} // expected-error@-1 {{assigning to 'struct spinlock_t' from incompatible type ''}} + +void fn2() { + audit_skb_queue + (lock); // expected-error {{use of undeclared identifier 'lock'; did you mean 'long'?}} +} // expected-error@-1 {{reference to overloaded function could not be resolved; did you mean to call it?}} diff --git a/test/SemaCXX/constexpr-string.cpp b/test/SemaCXX/constexpr-string.cpp index 944038bc163a..fba05e508ab7 100644 --- a/test/SemaCXX/constexpr-string.cpp +++ b/test/SemaCXX/constexpr-string.cpp @@ -166,6 +166,27 @@ namespace StrchrEtc { static_assert(__builtin_memchr(nullptr, 'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}} static_assert(__builtin_memchr(nullptr, 'x', 0) == nullptr); // FIXME: Should we reject this? + static_assert(__builtin_char_memchr(kStr, 'a', 0) == nullptr); + static_assert(__builtin_char_memchr(kStr, 'a', 1) == kStr); + static_assert(__builtin_char_memchr(kStr, '\0', 5) == nullptr); + static_assert(__builtin_char_memchr(kStr, '\0', 6) == kStr + 5); + static_assert(__builtin_char_memchr(kStr, '\xff', 8) == kStr + 4); + static_assert(__builtin_char_memchr(kStr, '\xff' + 256, 8) == kStr + 4); + static_assert(__builtin_char_memchr(kStr, '\xff' - 256, 8) == kStr + 4); + static_assert(__builtin_char_memchr(kFoo, 'x', 3) == nullptr); + static_assert(__builtin_char_memchr(kFoo, 'x', 4) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}} + static_assert(__builtin_char_memchr(nullptr, 'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}} + static_assert(__builtin_char_memchr(nullptr, 'x', 0) == nullptr); // FIXME: Should we reject this? + + static_assert(*__builtin_char_memchr(kStr, '\xff', 8) == '\xff'); + constexpr bool char_memchr_mutable() { + char buffer[] = "mutable"; + *__builtin_char_memchr(buffer, 't', 8) = 'r'; + *__builtin_char_memchr(buffer, 'm', 8) = 'd'; + return __builtin_strcmp(buffer, "durable") == 0; + } + static_assert(char_memchr_mutable()); + constexpr bool a = !strchr("hello", 'h'); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strchr' cannot be used in a constant expression}} constexpr bool b = !memchr("hello", 'h', 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'memchr' cannot be used in a constant expression}} } diff --git a/test/SemaCXX/cxx11-default-member-initializers.cpp b/test/SemaCXX/cxx11-default-member-initializers.cpp new file mode 100644 index 000000000000..9353e633fafb --- /dev/null +++ b/test/SemaCXX/cxx11-default-member-initializers.cpp @@ -0,0 +1,14 @@ +// RUN: %clang_cc1 -std=c++11 -verify %s -pedantic + +namespace PR31692 { + struct A { + struct X { int n = 0; } x; + // Trigger construction of X() from a SFINAE context. This must not mark + // any part of X as invalid. + static_assert(!__is_constructible(X), ""); + // Check that X::n is not marked invalid. + double &r = x.n; // expected-error {{non-const lvalue reference to type 'double' cannot bind to a value of unrelated type 'int'}} + }; + // A::X can now be default-constructed. + static_assert(__is_constructible(A::X), ""); +}