r199513 - Fix string-literal to char* conversion in overload resolution for C++11
Evgeniy Stepanov
eugeni.stepanov at gmail.com
Fri Jan 24 01:02:27 PST 2014
The bot was down until less than a day ago, so no one actually new
about the issue. I guess it's ok to wait another day.
On Fri, Jan 24, 2014 at 12:55 PM, Chandler Carruth <chandlerc at google.com> wrote:
> Can we revert until a fix is ready? 7 days with msan failures is too many.
>
>
> On Thu, Jan 23, 2014 at 8:08 PM, Richard Smith <metafoo at gmail.com> wrote:
>>
>> Looks like the msan build bot has found a bug here:
>>
>>
>> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/1844/steps/annotate/logs/stdio
>>
>> It appears that some path through the code doesn't initialize
>> DeprecatedStringLiteralToCharPtr.
>>
>> On Fri Jan 17 2014 at 1:15:20 PM, Ismail Pazarbasi
>> <ismail.pazarbasi at gmail.com> wrote:
>>
>> Author: ismailp
>> Date: Fri Jan 17 15:08:52 2014
>> New Revision: 199513
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=199513&view=rev
>> Log:
>> Fix string-literal to char* conversion in overload resolution for C++11
>>
>> String literal to char* conversion is deprecated in C++03, and is removed
>> in
>> C++11. We still accept this conversion in C++11 mode as an extension, if
>> we find
>> it in the best viable function.
>>
>>
>> Modified:
>> cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>> cfe/trunk/lib/Sema/SemaExprCXX.cpp
>> cfe/trunk/lib/Sema/SemaOverload.cpp
>> cfe/trunk/test/SemaCXX/cxx0x-type-convert-construct.cpp
>> cfe/trunk/test/SemaCXX/deprecated.cpp
>> cfe/trunk/test/SemaCXX/overload-0x.cpp
>> cfe/trunk/unittests/ASTMatchers/ASTMatchersTest.cpp
>>
>> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=199513&r1=199512&r2=199513&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri Jan 17
>> 15:08:52 2014
>> @@ -4534,6 +4534,9 @@ def ext_array_init_parens : ExtWarn<
>> def warn_deprecated_string_literal_conversion : Warning<
>> "conversion from string literal to %0 is deprecated">,
>> InGroup<CXX11CompatDeprecatedWritableStr>;
>> +def ext_deprecated_string_literal_conversion : ExtWarn<
>> + "ISO C++11 does not allow conversion from string literal to %0">,
>> + InGroup<CXX11CompatDeprecatedWritableStr>, SFINAEFailure;
>> def warn_deprecated_string_literal_conversion_c : Warning<
>> "dummy warning to enable -fconst-strings">,
>> InGroup<DeprecatedWritableStr>, DefaultIgnore;
>> def err_realimag_invalid_type : Error<"invalid type %0 to %1 operator">;
>>
>> Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=199513&r1=199512&r2=199513&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Fri Jan 17 15:08:52 2014
>> @@ -3058,9 +3058,12 @@ Sema::PerformImplicitConversion(Expr *Fr
>> CK_NoOp, VK, /*BasePath=*/0, CCK).take();
>>
>> if (SCS.DeprecatedStringLiteralToCharPtr &&
>> - !getLangOpts().WritableStrings)
>> - Diag(From->getLocStart(),
>> diag::warn_deprecated_string_literal_conversion)
>> + !getLangOpts().WritableStrings) {
>> + Diag(From->getLocStart(), getLangOpts().CPlusPlus11
>> + ? diag::ext_deprecated_string_literal_conversion
>> + : diag::warn_deprecated_string_literal_conversion)
>> << ToType.getNonReferenceType();
>> + }
>>
>> break;
>> }
>>
>> Modified: cfe/trunk/lib/Sema/SemaOverload.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=199513&r1=199512&r2=199513&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaOverload.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaOverload.cpp Fri Jan 17 15:08:52 2014
>> @@ -1443,7 +1443,6 @@ static bool IsStandardConversion(Sema &S
>>
>> // Standard conversions (C++ [conv])
>> SCS.setAsIdentityConversion();
>> - SCS.DeprecatedStringLiteralToCharPtr = false;
>> SCS.IncompatibleObjC = false;
>> SCS.setFromType(FromType);
>> SCS.CopyConstructor = 0;
>> @@ -1542,7 +1541,7 @@ static bool IsStandardConversion(Sema &S
>> FromType = S.Context.getArrayDecayedType(FromType);
>>
>> if (S.IsStringLiteralToNonConstPointerConversion(From, ToType)) {
>> - // This conversion is deprecated. (C++ D.4).
>> + // This conversion is deprecated in C++03 (D.4)
>> SCS.DeprecatedStringLiteralToCharPtr = true;
>>
>> // For the purpose of ranking in overload resolution
>> @@ -3259,18 +3258,15 @@ Sema::DiagnoseMultipleUserDefinedConvers
>> IsUserDefinedConversion(*this, From, ToType, ICS.UserDefined,
>> CandidateSet, false, false);
>> if (OvResult == OR_Ambiguous)
>> - Diag(From->getLocStart(),
>> - diag::err_typecheck_ambiguous_condition)
>> - << From->getType() << ToType << From->getSourceRange();
>> + Diag(From->getLocStart(), diag::err_typecheck_ambiguous_condition)
>> + << From->getType() << ToType << From->getSourceRange();
>> else if (OvResult == OR_No_Viable_Function && !CandidateSet.empty()) {
>> if (!RequireCompleteType(From->getLocStart(), ToType,
>> -
>> diag::err_typecheck_nonviable_condition_incomplete,
>> +
>> diag::err_typecheck_nonviable_condition_incomplete,
>> From->getType(), From->getSourceRange()))
>> - Diag(From->getLocStart(),
>> - diag::err_typecheck_nonviable_condition)
>> - << From->getType() << From->getSourceRange() << ToType;
>> - }
>> - else
>> + Diag(From->getLocStart(), diag::err_typecheck_nonviable_condition)
>> + << From->getType() << From->getSourceRange() << ToType;
>> + } else
>> return false;
>> CandidateSet.NoteCandidates(*this, OCD_AllCandidates, From);
>> return true;
>> @@ -3280,37 +3276,43 @@ Sema::DiagnoseMultipleUserDefinedConvers
>> /// of two user-defined conversion sequences to determine whether any
>> ordering
>> /// is possible.
>> static ImplicitConversionSequence::CompareKind
>> -compareConversionFunctions(Sema &S,
>> - FunctionDecl *Function1,
>> +compareConversionFunctions(Sema &S, FunctionDecl *Function1,
>> FunctionDecl *Function2) {
>> if (!S.getLangOpts().ObjC1 || !S.getLangOpts().CPlusPlus11)
>> return ImplicitConversionSequence::Indistinguishable;
>> -
>> +
>> // Objective-C++:
>> // If both conversion functions are implicitly-declared conversions
>> from
>> - // a lambda closure type to a function pointer and a block pointer,
>> + // a lambda closure type to a function pointer and a block pointer,
>> // respectively, always prefer the conversion to a function pointer,
>> // because the function pointer is more lightweight and is more
>> likely
>> // to keep code working.
>> CXXConversionDecl *Conv1 = dyn_cast<CXXConversionDecl>(Function1);
>> if (!Conv1)
>> return ImplicitConversionSequence::Indistinguishable;
>> -
>> +
>> CXXConversionDecl *Conv2 = dyn_cast<CXXConversionDecl>(Function2);
>> if (!Conv2)
>> return ImplicitConversionSequence::Indistinguishable;
>> -
>> +
>> if (Conv1->getParent()->isLambda() && Conv2->getParent()->isLambda()) {
>> bool Block1 = Conv1->getConversionType()->isBlockPointerType();
>> bool Block2 = Conv2->getConversionType()->isBlockPointerType();
>> if (Block1 != Block2)
>> - return Block1? ImplicitConversionSequence::Worse
>> - : ImplicitConversionSequence::Better;
>> + return Block1 ? ImplicitConversionSequence::Worse
>> + : ImplicitConversionSequence::Better;
>> }
>>
>> return ImplicitConversionSequence::Indistinguishable;
>> }
>> -
>> +
>> +static bool hasDeprecatedStringLiteralToCharPtrConversion(
>> + const ImplicitConversionSequence &ICS) {
>> + return (ICS.isStandard() &&
>> ICS.Standard.DeprecatedStringLiteralToCharPtr) ||
>> + (ICS.isUserDefined() &&
>> + ICS.UserDefined.Before.DeprecatedStringLiteralToCharPtr);
>> +}
>> +
>> /// CompareImplicitConversionSequences - Compare two implicit
>> /// conversion sequences to determine whether one is better than the
>> /// other or if they are indistinguishable (C++ 13.3.3.2).
>> @@ -3333,6 +3335,32 @@ CompareImplicitConversionSequences(Sema
>> // described in 13.3.3.2, the ambiguous conversion sequence is
>> // treated as a user-defined sequence that is indistinguishable
>> // from any other user-defined conversion sequence.
>> +
>> + // String literal to 'char *' conversion has been deprecated in C++03.
>> It has
>> + // been removed from C++11. We still accept this conversion, if it
>> happens at
>> + // the best viable function. Otherwise, this conversion is considered
>> worse
>> + // than ellipsis conversion. Consider this as an extension; this is not
>> in the
>> + // standard. For example:
>> + //
>> + // int &f(...); // #1
>> + // void f(char*); // #2
>> + // void g() { int &r = f("foo"); }
>> + //
>> + // In C++03, we pick #2 as the best viable function.
>> + // In C++11, we pick #1 as the best viable function, because ellipsis
>> + // conversion is better than string-literal to char* conversion (since
>> there
>> + // is no such conversion in C++11). If there was no #1 at all or #1
>> couldn't
>> + // convert arguments, #2 would be the best viable function in C++11.
>> + // If the best viable function has this conversion, a warning will be
>> issued
>> + // in C++03, or an ExtWarn (+SFINAE failure) will be issued in C++11.
>> +
>> + if (S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
>> + hasDeprecatedStringLiteralToCharPtrConversion(ICS1) !=
>> + hasDeprecatedStringLiteralToCharPtrConversion(ICS2))
>> + return hasDeprecatedStringLiteralToCharPtrConversion(ICS1)
>> + ? ImplicitConversionSequence::Worse
>> + : ImplicitConversionSequence::Better;
>> +
>> if (ICS1.getKindRank() < ICS2.getKindRank())
>> return ImplicitConversionSequence::Better;
>> if (ICS2.getKindRank() < ICS1.getKindRank())
>> @@ -4244,6 +4272,7 @@ TryReferenceInit(Sema &S, Expr *Init, Qu
>> ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier =
>> false;
>> ICS.Standard.ObjCLifetimeConversionBinding =
>> ObjCLifetimeConversion;
>> ICS.Standard.CopyConstructor = 0;
>> + ICS.Standard.DeprecatedStringLiteralToCharPtr = false;
>>
>> // Nothing more to do: the inaccessibility/ambiguity check for
>> // derived-to-base conversions is suppressed when we're
>> @@ -4318,6 +4347,7 @@ TryReferenceInit(Sema &S, Expr *Init, Qu
>> ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
>> ICS.Standard.ObjCLifetimeConversionBinding = ObjCLifetimeConversion;
>> ICS.Standard.CopyConstructor = 0;
>> + ICS.Standard.DeprecatedStringLiteralToCharPtr = false;
>> return ICS;
>> }
>>
>>
>> Modified: cfe/trunk/test/SemaCXX/cxx0x-type-convert-construct.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx0x-type-convert-construct.cpp?rev=199513&r1=199512&r2=199513&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/test/SemaCXX/cxx0x-type-convert-construct.cpp (original)
>> +++ cfe/trunk/test/SemaCXX/cxx0x-type-convert-construct.cpp Fri Jan 17
>> 15:08:52 2014
>> @@ -9,9 +9,9 @@ void f() {
>> Ustr = U"a UTF-32 string"; // expected-error {{assigning to 'char32_t
>> *' from incompatible type 'const char32_t [16]'}}
>>
>> char *Rstr;
>> - Rstr = R"foo(a raw string)foo"; // expected-warning{{conversion from
>> string literal to 'char *' is deprecated}}
>> + Rstr = R"foo(a raw string)foo"; // expected-warning{{ISO C++11 does not
>> allow conversion from string literal to 'char *'}}
>> wchar_t *LRstr;
>> - LRstr = LR"foo(a wide raw string)foo"; // expected-warning{{conversion
>> from string literal to 'wchar_t *' is deprecated}}
>> + LRstr = LR"foo(a wide raw string)foo"; // expected-warning{{ISO C++11
>> does not allow conversion from string literal to 'wchar_t *'}}
>> char *u8Rstr;
>> u8Rstr = u8R"foo(a UTF-8 raw string)foo"; // expected-error {{assigning
>> to 'char *' from incompatible type 'const char [19]'}}
>> char16_t *uRstr;
>>
>> Modified: cfe/trunk/test/SemaCXX/deprecated.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/deprecated.cpp?rev=199513&r1=199512&r2=199513&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/test/SemaCXX/deprecated.cpp (original)
>> +++ cfe/trunk/test/SemaCXX/deprecated.cpp Fri Jan 17 15:08:52 2014
>> @@ -24,12 +24,15 @@ void stuff() {
>> register int m asm("rbx"); // no-warning
>>
>> int k = to_int(n); // no-warning
>> -
>> bool b;
>> ++b; // expected-warning {{incrementing expression of type bool is
>> deprecated}}
>>
>> - // FIXME: This is ill-formed in C++11.
>> - char *p = "foo"; // expected-warning {{conversion from string literal
>> to 'char *' is deprecated}}
>> + char *p = "foo";
>> +#if __cplusplus < 201103L
>> + // expected-warning at -2 {{conversion from string literal to 'char *' is
>> deprecated}}
>> +#else
>> + // expected-warning at -4 {{ISO C++11 does not allow conversion from
>> string literal to 'char *'}}
>> +#endif
>> }
>>
>> struct S { int n; };
>>
>> Modified: cfe/trunk/test/SemaCXX/overload-0x.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/overload-0x.cpp?rev=199513&r1=199512&r2=199513&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/test/SemaCXX/overload-0x.cpp (original)
>> +++ cfe/trunk/test/SemaCXX/overload-0x.cpp Fri Jan 17 15:08:52 2014
>> @@ -1,7 +1,11 @@
>> -// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
>> +// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
>> +// RUN: %clang_cc1 -fsyntax-only -verify %s
>>
>> namespace test0 {
>> - struct A { // expected-note {{candidate function (the implicit copy
>> assignment operator) not viable: 'this' argument has type 'const test0::A',
>> but method is not marked const}} expected-note {{candidate function (the
>> implicit move assignment operator) not viable: 'this' argument has type
>> 'const test0::A', but method is not marked const}}
>> + struct A { // expected-note {{candidate function (the implicit copy
>> assignment operator) not viable: 'this' argument has type 'const test0::A',
>> but method is not marked const}}
>> +#if __cplusplus >= 201103L
>> + // expected-note at -2 {{candidate function (the implicit move assignment
>> operator) not viable: 'this' argument has type 'const test0::A', but method
>> is not marked const}}
>> +#endif
>> A &operator=(void*); // expected-note {{candidate function not
>> viable: 'this' argument has type 'const test0::A', but method is not marked
>> const}}
>> };
>>
>> @@ -9,3 +13,79 @@ namespace test0 {
>> a = "help"; // expected-error {{no viable overloaded '='}}
>> }
>> }
>> +
>> +namespace PR16314 {
>> + void f(char*);
>> + int &f(...);
>> + void x()
>> + {
>> + int &n = f("foo");
>> +#if __cplusplus < 201103L
>> + // expected-warning at -2 {{conversion from string literal to 'char *'
>> is deprecated}}
>> + // expected-error at -3 {{non-const lvalue reference to type 'int'
>> cannot bind to a temporary of type 'void'}}
>> +#endif
>> + }
>> +}
>> +
>> +namespace warn_if_best {
>> + int f(char *);
>> + void f(double);
>> + void x()
>> + {
>> + int n = f("foo");
>> +#if __cplusplus < 201103L
>> + // expected-warning at -2 {{conversion from string literal to 'char *'
>> is deprecated}}
>> +#else
>> + // expected-warning at -4 {{ISO C++11 does not allow conversion from
>> string literal to 'char *'}}
>> +#endif
>> + }
>> +}
>> +
>> +namespace userdefined_vs_illformed {
>> + struct X { X(const char *); };
>> +
>> + void *f(char *p); // best for C++03
>> + double f(X x); // best for C++11
>> + void g()
>> + {
>> + double d = f("foo");
>> +#if __cplusplus < 201103L
>> + // expected-warning at -2 {{conversion from string literal to 'char *'
>> is deprecated}}
>> + // expected-error at -3 {{cannot initialize a variable of type 'double'
>> with an rvalue of type 'void *'}}
>> +#endif
>> + }
>> +}
>> +
>> +namespace sfinae_test {
>> + int f(int, char*);
>> +
>> + template<int T>
>> + struct S { typedef int type; };
>> +
>> + template<>
>> + struct S<sizeof(int)> { typedef void type; };
>> +
>> + // C++11: SFINAE failure
>> + // C++03: ok
>> + template<typename T> int cxx11_ignored(T, typename S<sizeof(f(T(),
>> "foo"))>::type *);
>> +#if __cplusplus < 201103L
>> + // expected-warning at -2 {{conversion from string literal to 'char *' is
>> deprecated}}
>> +#else
>> + // expected-note at -4 {{candidate template ignored: substitution
>> failure}}
>> +#endif
>> +
>> + // C++11: better than latter
>> + // C++03: worse than latter
>> + template<typename T> void g(T, ...);
>> + template<typename T> int g(T, typename S<sizeof(f(T(), "foo"))>::type
>> *);
>> +#if __cplusplus < 201103L
>> + // expected-warning at -2 {{conversion from string literal to 'char *' is
>> deprecated}}
>> +#endif
>> +
>> + int a = cxx11_ignored(0, 0);
>> + int b = g(0, 0);
>> +#if __cplusplus >= 201103L
>> + // expected-error at -3 {{no matching function for call to
>> 'cxx11_ignored'}}
>> + // expected-error at -3 {{cannot initialize a variable of type 'int' with
>> an rvalue of type 'void'}}
>> +#endif
>> +}
>>
>> Modified: cfe/trunk/unittests/ASTMatchers/ASTMatchersTest.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/ASTMatchers/ASTMatchersTest.cpp?rev=199513&r1=199512&r2=199513&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/unittests/ASTMatchers/ASTMatchersTest.cpp (original)
>> +++ cfe/trunk/unittests/ASTMatchers/ASTMatchersTest.cpp Fri Jan 17
>> 15:08:52 2014
>> @@ -2608,13 +2608,13 @@ TEST(ReinterpretCast, DoesNotMatchOtherC
>> }
>>
>> TEST(FunctionalCast, MatchesSimpleCase) {
>> - std::string foo_class = "class Foo { public: Foo(char*); };";
>> + std::string foo_class = "class Foo { public: Foo(const char*); };";
>> EXPECT_TRUE(matches(foo_class + "void r() { Foo f = Foo(\"hello
>> world\"); }",
>> functionalCastExpr()));
>> }
>>
>> TEST(FunctionalCast, DoesNotMatchOtherCasts) {
>> - std::string FooClass = "class Foo { public: Foo(char*); };";
>> + std::string FooClass = "class Foo { public: Foo(const char*); };";
>> EXPECT_TRUE(
>> notMatches(FooClass + "void r() { Foo f = (Foo) \"hello world\";
>> }",
>> functionalCastExpr()));
>>
>>
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