User-defined literals: reject string and character UDLs in all places where the

grammar requires a string-literal and not a user-defined-string-literal. The
two constructs are still represented by the same TokenKind, in order to prevent
a combinatorial explosion of different kinds of token. A flag on Token tracks
whether a ud-suffix is present, in order to prevent clients from needing to look
at the token's spelling.

llvm-svn: 152098
This commit is contained in:
Richard Smith 2012-03-06 03:21:47 +00:00
parent 8de0744441
commit d67aea28f6
24 changed files with 245 additions and 40 deletions

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@ -41,6 +41,8 @@ def err_expected_colon : Error<"expected ':'">;
def err_expected_colon_after_setter_name : Error<
"method name referenced in property setter attribute "
"must end with ':'">;
def err_invalid_string_udl : Error<
"string literal with user-defined suffix cannot be used here">;
// Parse && Sema
def ext_no_declarators : ExtWarn<"declaration does not declare anything">,

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@ -136,6 +136,9 @@ def err_unsupported_string_concat : Error<
def err_string_concat_mixed_suffix : Error<
"differing user-defined suffixes ('%0' and '%1') in string literal "
"concatenation">;
def err_pp_invalid_char_udl : Error<
"character literal with user-defined suffix cannot be used in preprocessor "
"constant expression">;
def err_bad_string_encoding : Error<
"illegal character encoding in string literal">;
def warn_bad_string_encoding : ExtWarn<

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@ -200,7 +200,7 @@ def err_address_of_label_outside_fn : Error<
"use of address-of-label extension outside of a function body">;
def err_expected_string_literal : Error<"expected string literal">;
def err_asm_operand_wide_string_literal : Error<
"cannot use wide string literal in 'asm'">;
"cannot use %select{unicode|wide}0 string literal in 'asm'">;
def err_expected_selector_for_method : Error<
"expected selector for Objective-C method">;
def err_expected_property_name : Error<"expected property name">;
@ -425,8 +425,11 @@ def err_parser_impl_limit_overflow : Error<
def err_dup_virtual : Error<"duplicate 'virtual' in base specifier">;
// C++ operator overloading
def err_operator_string_not_empty : Error<
def err_literal_operator_string_not_empty : Error<
"string literal after 'operator' must be '\"\"'">;
def err_literal_operator_missing_space : Error<
"C++11 requires a space between the \"\" and the user-defined suffix in a "
"literal operator">;
def warn_cxx98_compat_literal_operator : Warning<
"literal operators are incompatible with C++98">,
InGroup<CXX98Compat>, DefaultIgnore;

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@ -75,7 +75,8 @@ public:
LeadingSpace = 0x02, // Whitespace exists before this token.
DisableExpand = 0x04, // This identifier may never be macro expanded.
NeedsCleaning = 0x08, // Contained an escaped newline or trigraph.
LeadingEmptyMacro = 0x10 // Empty macro exists before this token.
LeadingEmptyMacro = 0x10, // Empty macro exists before this token.
HasUDSuffix = 0x20 // This string or character literal has a ud-suffix.
};
tok::TokenKind getKind() const { return (tok::TokenKind)Kind; }
@ -263,6 +264,9 @@ public:
return (Flags & LeadingEmptyMacro) ? true : false;
}
/// \brief Return true if this token is a string or character literal which
/// has a ud-suffix.
bool hasUDSuffix() const { return (Flags & HasUDSuffix) ? true : false; }
};
/// PPConditionalInfo - Information about the conditional stack (#if directives)

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@ -1359,7 +1359,7 @@ private:
SourceLocation LParenLoc,
SourceLocation RParenLoc);
ExprResult ParseStringLiteralExpression();
ExprResult ParseStringLiteralExpression(bool AllowUserDefinedLiteral = false);
ExprResult ParseGenericSelectionExpression();

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@ -1582,6 +1582,7 @@ const char *Lexer::LexUDSuffix(Token &Result, const char *CurPtr) {
unsigned Size;
char C = getCharAndSize(CurPtr, Size);
if (isIdentifierHead(C)) {
Result.setFlag(Token::HasUDSuffix);
do {
CurPtr = ConsumeChar(CurPtr, Size, Result);
C = getCharAndSize(CurPtr, Size);

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@ -617,6 +617,12 @@ retry:
break;
case tok::string_literal: {
if (LToken.hasUDSuffix()) {
Diags.Report(LToken.getLocation(), diag::err_invalid_string_udl);
HadError = true;
goto retry;
}
// Parse the string literal.
LangOptions LangOpts;
StringLiteralParser StringLiteral(&LToken, 1, SourceMgr, LangOpts, *Target);

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@ -822,8 +822,10 @@ void Preprocessor::HandleLineDirective(Token &Tok) {
; // ok
else if (StrTok.isNot(tok::string_literal)) {
Diag(StrTok, diag::err_pp_line_invalid_filename);
DiscardUntilEndOfDirective();
return;
return DiscardUntilEndOfDirective();
} else if (StrTok.hasUDSuffix()) {
Diag(StrTok, diag::err_invalid_string_udl);
return DiscardUntilEndOfDirective();
} else {
// Parse and validate the string, converting it into a unique ID.
StringLiteralParser Literal(&StrTok, 1, *this);
@ -957,6 +959,9 @@ void Preprocessor::HandleDigitDirective(Token &DigitTok) {
else if (StrTok.isNot(tok::string_literal)) {
Diag(StrTok, diag::err_pp_linemarker_invalid_filename);
return DiscardUntilEndOfDirective();
} else if (StrTok.hasUDSuffix()) {
Diag(StrTok, diag::err_invalid_string_udl);
return DiscardUntilEndOfDirective();
} else {
// Parse and validate the string, converting it into a unique ID.
StringLiteralParser Literal(&StrTok, 1, *this);
@ -1047,6 +1052,11 @@ void Preprocessor::HandleIdentSCCSDirective(Token &Tok) {
return;
}
if (StrTok.hasUDSuffix()) {
Diag(StrTok, diag::err_invalid_string_udl);
return DiscardUntilEndOfDirective();
}
// Verify that there is nothing after the string, other than EOD.
CheckEndOfDirective("ident");

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@ -251,6 +251,10 @@ static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
case tok::wide_char_constant: { // L'x'
case tok::utf16_char_constant: // u'x'
case tok::utf32_char_constant: // U'x'
// Complain about, and drop, any ud-suffix.
if (PeekTok.hasUDSuffix())
PP.Diag(PeekTok, diag::err_pp_invalid_char_udl);
SmallString<32> CharBuffer;
bool CharInvalid = false;
StringRef ThisTok = PP.getSpelling(PeekTok, CharBuffer, &CharInvalid);

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@ -825,6 +825,16 @@ static bool EvaluateHasIncludeCommon(Token &Tok,
return false;
}
// Get ')'.
PP.LexNonComment(Tok);
// Ensure we have a trailing ).
if (Tok.isNot(tok::r_paren)) {
PP.Diag(Tok.getLocation(), diag::err_pp_missing_rparen) << II->getName();
PP.Diag(LParenLoc, diag::note_matching) << "(";
return false;
}
bool isAngled = PP.GetIncludeFilenameSpelling(Tok.getLocation(), Filename);
// If GetIncludeFilenameSpelling set the start ptr to null, there was an
// error.
@ -836,20 +846,8 @@ static bool EvaluateHasIncludeCommon(Token &Tok,
const FileEntry *File =
PP.LookupFile(Filename, isAngled, LookupFrom, CurDir, NULL, NULL, NULL);
// Get the result value. Result = true means the file exists.
bool Result = File != 0;
// Get ')'.
PP.LexNonComment(Tok);
// Ensure we have a trailing ).
if (Tok.isNot(tok::r_paren)) {
PP.Diag(Tok.getLocation(), diag::err_pp_missing_rparen) << II->getName();
PP.Diag(LParenLoc, diag::note_matching) << "(";
return false;
}
return Result;
// Get the result value. A result of true means the file exists.
return File != 0;
}
/// EvaluateHasInclude - Process a '__has_include("path")' expression.
@ -1091,6 +1089,9 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
// from macro expansion.
SmallVector<Token, 4> StrToks;
while (Tok.is(tok::string_literal)) {
// Complain about, and drop, any ud-suffix.
if (Tok.hasUDSuffix())
Diag(Tok, diag::err_invalid_string_udl);
StrToks.push_back(Tok);
LexUnexpandedToken(Tok);
}

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@ -133,6 +133,20 @@ void Preprocessor::Handle_Pragma(Token &Tok) {
Lex(Tok);
if (Tok.isNot(tok::string_literal) && Tok.isNot(tok::wide_string_literal)) {
Diag(PragmaLoc, diag::err__Pragma_malformed);
// Skip this token, and the ')', if present.
if (Tok.isNot(tok::r_paren))
Lex(Tok);
if (Tok.is(tok::r_paren))
Lex(Tok);
return;
}
if (Tok.hasUDSuffix()) {
Diag(Tok, diag::err_invalid_string_udl);
// Skip this token, and the ')', if present.
Lex(Tok);
if (Tok.is(tok::r_paren))
Lex(Tok);
return;
}
@ -442,6 +456,8 @@ void Preprocessor::HandlePragmaComment(Token &Tok) {
// "foo " "bar" "Baz"
SmallVector<Token, 4> StrToks;
while (Tok.is(tok::string_literal)) {
if (Tok.hasUDSuffix())
Diag(Tok, diag::err_invalid_string_udl);
StrToks.push_back(Tok);
Lex(Tok);
}
@ -518,6 +534,8 @@ void Preprocessor::HandlePragmaMessage(Token &Tok) {
// "foo " "bar" "Baz"
SmallVector<Token, 4> StrToks;
while (Tok.is(tok::string_literal)) {
if (Tok.hasUDSuffix())
Diag(Tok, diag::err_invalid_string_udl);
StrToks.push_back(Tok);
Lex(Tok);
}
@ -577,6 +595,11 @@ IdentifierInfo *Preprocessor::ParsePragmaPushOrPopMacro(Token &Tok) {
return 0;
}
if (Tok.hasUDSuffix()) {
Diag(Tok, diag::err_invalid_string_udl);
return 0;
}
// Remember the macro string.
std::string StrVal = getSpelling(Tok);

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@ -85,6 +85,19 @@ TokenConcatenation::TokenConcatenation(Preprocessor &pp) : PP(pp) {
TokenInfo[tok::hash ] |= aci_custom_firstchar;
TokenInfo[tok::arrow ] |= aci_custom_firstchar;
// These tokens have custom code in C++11 mode.
if (PP.getLangOptions().CPlusPlus0x) {
TokenInfo[tok::string_literal ] |= aci_custom;
TokenInfo[tok::wide_string_literal ] |= aci_custom;
TokenInfo[tok::utf8_string_literal ] |= aci_custom;
TokenInfo[tok::utf16_string_literal] |= aci_custom;
TokenInfo[tok::utf32_string_literal] |= aci_custom;
TokenInfo[tok::char_constant ] |= aci_custom;
TokenInfo[tok::wide_char_constant ] |= aci_custom;
TokenInfo[tok::utf16_char_constant ] |= aci_custom;
TokenInfo[tok::utf32_char_constant ] |= aci_custom;
}
// These tokens change behavior if followed by an '='.
TokenInfo[tok::amp ] |= aci_avoid_equal; // &=
TokenInfo[tok::plus ] |= aci_avoid_equal; // +=
@ -183,6 +196,28 @@ bool TokenConcatenation::AvoidConcat(const Token &PrevPrevTok,
case tok::raw_identifier:
llvm_unreachable("tok::raw_identifier in non-raw lexing mode!");
case tok::string_literal:
case tok::wide_string_literal:
case tok::utf8_string_literal:
case tok::utf16_string_literal:
case tok::utf32_string_literal:
case tok::char_constant:
case tok::wide_char_constant:
case tok::utf16_char_constant:
case tok::utf32_char_constant:
if (!PP.getLangOptions().CPlusPlus0x)
return false;
// In C++11, a string or character literal followed by an identifier is a
// single token.
if (Tok.getIdentifierInfo())
return true;
// A ud-suffix is an identifier. If the previous token ends with one, treat
// it as an identifier.
if (!PrevTok.hasUDSuffix())
return false;
// FALL THROUGH.
case tok::identifier: // id+id or id+number or id+L"foo".
// id+'.'... will not append.
if (Tok.is(tok::numeric_constant))
@ -201,9 +236,11 @@ bool TokenConcatenation::AvoidConcat(const Token &PrevPrevTok,
// Otherwise, this is a narrow character or string. If the *identifier*
// is a literal 'L', 'u8', 'u' or 'U', avoid pasting L "foo" -> L"foo".
return IsIdentifierStringPrefix(PrevTok);
case tok::numeric_constant:
return isalnum(FirstChar) || Tok.is(tok::numeric_constant) ||
FirstChar == '+' || FirstChar == '-' || FirstChar == '.';
FirstChar == '+' || FirstChar == '-' || FirstChar == '.' ||
(PP.getLangOptions().CPlusPlus0x && FirstChar == '_');
case tok::period: // ..., .*, .1234
return (FirstChar == '.' && PrevPrevTok.is(tok::period)) ||
isdigit(FirstChar) ||

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@ -272,6 +272,11 @@ Decl *Parser::ParseLinkage(ParsingDeclSpec &DS, unsigned Context) {
if (Invalid)
return 0;
// FIXME: This is incorrect: linkage-specifiers are parsed in translation
// phase 7, so string-literal concatenation is supposed to occur.
// extern "" "C" "" "+" "+" { } is legal.
if (Tok.hasUDSuffix())
Diag(Tok, diag::err_invalid_string_udl);
SourceLocation Loc = ConsumeStringToken();
ParseScope LinkageScope(this, Scope::DeclScope);
@ -617,8 +622,10 @@ Decl *Parser::ParseStaticAssertDeclaration(SourceLocation &DeclEnd){
}
ExprResult AssertMessage(ParseStringLiteralExpression());
if (AssertMessage.isInvalid())
if (AssertMessage.isInvalid()) {
SkipUntil(tok::semi);
return 0;
}
T.consumeClose();

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@ -497,14 +497,14 @@ class CastExpressionIdValidator : public CorrectionCandidateCallback {
/// unary-operator cast-expression
/// 'sizeof' unary-expression
/// 'sizeof' '(' type-name ')'
/// [C++0x] 'sizeof' '...' '(' identifier ')'
/// [C++11] 'sizeof' '...' '(' identifier ')'
/// [GNU] '__alignof' unary-expression
/// [GNU] '__alignof' '(' type-name ')'
/// [C++0x] 'alignof' '(' type-id ')'
/// [C++11] 'alignof' '(' type-id ')'
/// [GNU] '&&' identifier
/// [C++11] 'noexcept' '(' expression ')' [C++11 5.3.7]
/// [C++] new-expression
/// [C++] delete-expression
/// [C++0x] 'noexcept' '(' expression ')'
///
/// unary-operator: one of
/// '&' '*' '+' '-' '~' '!'
@ -516,7 +516,8 @@ class CastExpressionIdValidator : public CorrectionCandidateCallback {
/// constant
/// string-literal
/// [C++] boolean-literal [C++ 2.13.5]
/// [C++0x] 'nullptr' [C++0x 2.14.7]
/// [C++11] 'nullptr' [C++11 2.14.7]
/// [C++11] user-defined-literal
/// '(' expression ')'
/// [C11] generic-selection
/// '__func__' [C99 6.4.2.2]
@ -535,9 +536,9 @@ class CastExpressionIdValidator : public CorrectionCandidateCallback {
/// [OBJC] '@encode' '(' type-name ')'
/// [OBJC] objc-string-literal
/// [C++] simple-type-specifier '(' expression-list[opt] ')' [C++ 5.2.3]
/// [C++0x] simple-type-specifier braced-init-list [C++ 5.2.3]
/// [C++11] simple-type-specifier braced-init-list [C++11 5.2.3]
/// [C++] typename-specifier '(' expression-list[opt] ')' [C++ 5.2.3]
/// [C++0x] typename-specifier braced-init-list [C++ 5.2.3]
/// [C++11] typename-specifier braced-init-list [C++11 5.2.3]
/// [C++] 'const_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
/// [C++] 'dynamic_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
/// [C++] 'reinterpret_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
@ -850,7 +851,7 @@ ExprResult Parser::ParseCastExpression(bool isUnaryExpression,
case tok::utf8_string_literal:
case tok::utf16_string_literal:
case tok::utf32_string_literal:
Res = ParseStringLiteralExpression();
Res = ParseStringLiteralExpression(true);
break;
case tok::kw__Generic: // primary-expression: generic-selection [C11 6.5.1]
Res = ParseGenericSelectionExpression();
@ -2102,7 +2103,7 @@ Parser::ParseCompoundLiteralExpression(ParsedType Ty,
///
/// primary-expression: [C99 6.5.1]
/// string-literal
ExprResult Parser::ParseStringLiteralExpression() {
ExprResult Parser::ParseStringLiteralExpression(bool AllowUserDefinedLiteral) {
assert(isTokenStringLiteral() && "Not a string literal!");
// String concat. Note that keywords like __func__ and __FUNCTION__ are not
@ -2110,6 +2111,12 @@ ExprResult Parser::ParseStringLiteralExpression() {
SmallVector<Token, 4> StringToks;
do {
if (!AllowUserDefinedLiteral && Tok.hasUDSuffix()) {
Diag(Tok, diag::err_invalid_string_udl);
do ConsumeStringToken(); while (isTokenStringLiteral());
return ExprError();
}
StringToks.push_back(Tok);
ConsumeStringToken();
} while (isTokenStringLiteral());

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@ -1905,8 +1905,13 @@ bool Parser::ParseUnqualifiedIdOperator(CXXScopeSpec &SS, bool EnteringContext,
if (getLang().CPlusPlus0x && Tok.is(tok::string_literal)) {
Diag(Tok.getLocation(), diag::warn_cxx98_compat_literal_operator);
// FIXME: Add a FixIt to insert a space before the suffix, and recover.
if (Tok.hasUDSuffix()) {
Diag(Tok.getLocation(), diag::err_literal_operator_missing_space);
return true;
}
if (Tok.getLength() != 2)
Diag(Tok.getLocation(), diag::err_operator_string_not_empty);
Diag(Tok.getLocation(), diag::err_literal_operator_string_not_empty);
ConsumeStringToken();
if (Tok.isNot(tok::identifier)) {

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@ -2011,6 +2011,8 @@ ExprResult Parser::ParseObjCAtExpression(SourceLocation AtLoc) {
case tok::string_literal: // primary-expression: string-literal
case tok::wide_string_literal:
if (Tok.hasUDSuffix())
return ExprError(Diag(Tok, diag::err_invalid_string_udl));
return ParsePostfixExpressionSuffix(ParseObjCStringLiteral(AtLoc));
default:
if (Tok.getIdentifierInfo() == 0)

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@ -1797,10 +1797,8 @@ StmtResult Parser::ParseAsmStatement(bool &msAsm) {
ExprResult AsmString(ParseAsmStringLiteral());
if (AsmString.isInvalid()) {
// If the reason we are recovering is because of an improper string
// literal, it makes the most sense just to consume to the ')'.
if (isTokenStringLiteral())
T.skipToEnd();
// Consume up to and including the closing paren.
T.skipToEnd();
return StmtError();
}

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@ -1127,9 +1127,13 @@ Parser::ExprResult Parser::ParseAsmStringLiteral() {
switch (Tok.getKind()) {
case tok::string_literal:
break;
case tok::utf8_string_literal:
case tok::utf16_string_literal:
case tok::utf32_string_literal:
case tok::wide_string_literal: {
SourceLocation L = Tok.getLocation();
Diag(Tok, diag::err_asm_operand_wide_string_literal)
<< (Tok.getKind() == tok::wide_string_literal)
<< SourceRange(L, L);
return ExprError();
}
@ -1138,10 +1142,7 @@ Parser::ExprResult Parser::ParseAsmStringLiteral() {
return ExprError();
}
ExprResult Res(ParseStringLiteralExpression());
if (Res.isInvalid()) return move(Res);
return move(Res);
return ParseStringLiteralExpression();
}
/// ParseSimpleAsm

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@ -409,6 +409,7 @@ void html::SyntaxHighlight(Rewriter &R, FileID FID, const Preprocessor &PP) {
--TokLen;
// FALL THROUGH.
case tok::string_literal:
// FIXME: Exclude the optional ud-suffix from the highlighted range.
HighlightRange(RB, TokOffs, TokOffs+TokLen, BufferStart,
"<span class='string_literal'>", "</span>");
break;

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@ -10,7 +10,7 @@ string operator "" _i18n(const char*, std::size_t); // ok
// FIXME: This should be accepted once we support UCNs
template<char...> int operator "" \u03C0(); // ok, UCN for lowercase pi // expected-error {{expected identifier}}
// FIXME: Accept this as an extension, with a fix-it to add the space
float operator ""E(const char *); // expected-error {{must be '""'}} expected-error {{expected identifier}}
float operator ""E(const char *); // expected-error {{C++11 requires a space between the "" and the user-defined suffix in a literal operator}}
float operator " " B(const char *); // expected-error {{must be '""'}} expected-warning {{hexfloat}}
string operator "" 5X(const char *, std::size_t); // expected-error {{expected identifier}}
double operator "" _miles(double); // expected-error {{parameter}}

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@ -0,0 +1,19 @@
// RUN: %clang_cc1 -E -std=c++11 -o - %s | FileCheck %s
#define id(x) x
id("s")_x // CHECK: "s" _x
id(L"s")_x // CHECK: L"s" _x
id(u8"s")_x // CHECK: u8"s" _x
id(u"s")_x // CHECK: u"s" _x
id(U"s")_x // CHECK: U"s" _x
id('s')_x // CHECK: 's' _x
id(L's')_x // CHECK: L's' _x
id(u's')_x // CHECK: u's' _x
id(U's')_x // CHECK: U's' _x
id("s"_x)_y // CHECK: "s"_x _y
id(1.0_)f // CHECK: 1.0_ f
id(1.0)_f // CHECK: 1.0 _f
id(0xface+)b_count // CHECK: 0xface+ b_count
id("s")1 // CHECK: "s"1
id("s"_x)1 // CHECK: "s"_x 1
id(1)_2_x // CHECK: 1 _2_x

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@ -0,0 +1,8 @@
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
int foo1 asm ("bar1");
int foo2 asm (L"bar2"); // expected-error {{cannot use wide string literal in 'asm'}}
int foo3 asm (u8"bar3"); // expected-error {{cannot use unicode string literal in 'asm'}}
int foo4 asm (u"bar4"); // expected-error {{cannot use unicode string literal in 'asm'}}
int foo5 asm (U"bar5"); // expected-error {{cannot use unicode string literal in 'asm'}}
int foo6 asm ("bar6"_x); // expected-error {{string literal with user-defined suffix cannot be used here}}

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@ -0,0 +1,60 @@
// RUN: %clang_cc1 -std=c++11 -verify %s -fms-extensions -triple x86_64-apple-darwin9.0.0
// A ud-suffix cannot be used on string literals in a whole bunch of contexts:
#include "foo"_bar // expected-error {{expected "FILENAME" or <FILENAME>}}
#line 1 "foo"_bar // expected-error {{user-defined suffix cannot be used here}}
# 1 "foo"_bar 1 // expected-error {{user-defined suffix cannot be used here}}
#ident "foo"_bar // expected-error {{user-defined suffix cannot be used here}}
_Pragma("foo"_bar) // expected-error {{user-defined suffix cannot be used here}}
#pragma comment(lib, "foo"_bar) // expected-error {{user-defined suffix cannot be used here}}
_Pragma("comment(lib, \"foo\"_bar)") // expected-error {{user-defined suffix cannot be used here}}
#pragma message "hi"_there // expected-error {{user-defined suffix cannot be used here}} expected-warning {{hi}}
#pragma push_macro("foo"_bar) // expected-error {{user-defined suffix cannot be used here}}
#if __has_warning("-Wan-island-to-discover"_bar) // expected-error {{user-defined suffix cannot be used here}}
#elif __has_include("foo"_bar) // expected-error {{expected "FILENAME" or <FILENAME>}}
#endif
extern "C++"_x {} // expected-error {{user-defined suffix cannot be used here}} expected-error {{unknown linkage language}}
int f() {
asm("mov %eax, %rdx"_foo); // expected-error {{user-defined suffix cannot be used here}}
}
static_assert(true, "foo"_bar); // expected-error {{user-defined suffix cannot be used here}}
int cake() __attribute__((availability(macosx, unavailable, message = "is a lie"_x))); // expected-error {{user-defined suffix cannot be used here}}
// A ud-suffix cannot be used on character literals in preprocessor constant
// expressions:
#if 'x'_y - u'x'_z // expected-error 2{{character literal with user-defined suffix cannot be used in preprocessor constant expression}}
#error error
#endif
// But they can appear in expressions.
constexpr char operator"" _id(char c) { return c; }
constexpr wchar_t operator"" _id(wchar_t c) { return c; }
constexpr char16_t operator"" _id(char16_t c) { return c; }
constexpr char32_t operator"" _id(char32_t c) { return c; }
using size_t = decltype(sizeof(int));
constexpr const char operator"" _id(const char *p, size_t n) { return *p; }
constexpr const wchar_t operator"" _id(const wchar_t *p, size_t n) { return *p; }
constexpr const char16_t operator"" _id(const char16_t *p, size_t n) { return *p; }
constexpr const char32_t operator"" _id(const char32_t *p, size_t n) { return *p; }
template<int n> struct S {};
S<"a"_id[0]> sa;
S<L"b"_id[0]> sb;
S<u8"c"_id[0]> sc;
S<u"d"_id[0]> sd;
S<U"e"_id[0]> se;
S<'w'_id> sw;
S<L'x'_id> sx;
S<u'y'_id> sy;
S<U'z'_id> sz;
void h() {
(void)"test"_id "test" L"test";
}

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@ -0,0 +1,3 @@
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
id x = @"foo"_bar; // expected-error{{user-defined suffix cannot be used here}}