Commit 55a51e1c authored by Aaron Ballman's avatar Aaron Ballman
Browse files

Disallow an empty string literal in an asm label 

An empty string literal in an asm label does not make a whole lot of sense. GCC
does not diagnose such a construct, but it also generates code that cannot be
assembled by gas should two symbols have an empty asm label within the same TU.
This does not affect an asm statement with an empty string literal, which is
still a useful construct.
parent 111ec8c2

clang/include/clang/Basic/DiagnosticParseKinds.td

+1 −1
Original line number Diff line number Diff line
@@ -265,7 +265,7 @@ def err_label_end_of_compound_statement : Error< 
def err_address_of_label_outside_fn : Error<

  "use of address-of-label extension outside of a function body">;

def err_asm_operand_wide_string_literal : Error<

  "cannot use %select{unicode|wide}0 string literal in 'asm'">;

  "cannot use %select{unicode|wide|an empty}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">;

clang/include/clang/Parse/Parser.h

+3 −4
Original line number Diff line number Diff line
@@ -1532,10 +1532,9 @@ private: 
                 const ParsedTemplateInfo &TemplateInfo = ParsedTemplateInfo(),

                 LateParsedAttrList *LateParsedAttrs = nullptr);

  void ParseKNRParamDeclarations(Declarator &D);

  // EndLoc, if non-NULL, is filled with the location of the last token of

  // the simple-asm.

  ExprResult ParseSimpleAsm(SourceLocation *EndLoc = nullptr);

  ExprResult ParseAsmStringLiteral();

  // EndLoc is filled with the location of the last token of the simple-asm.

  ExprResult ParseSimpleAsm(bool ForAsmLabel, SourceLocation *EndLoc);

  ExprResult ParseAsmStringLiteral(bool ForAsmLabel);



  // Objective-C External Declarations

  void MaybeSkipAttributes(tok::ObjCKeywordKind Kind);

clang/lib/Parse/ParseDecl.cpp

+1 −1
Original line number Diff line number Diff line
@@ -2197,7 +2197,7 @@ bool Parser::ParseAsmAttributesAfterDeclarator(Declarator &D) { 
  // If a simple-asm-expr is present, parse it.

  if (Tok.is(tok::kw_asm)) {

    SourceLocation Loc;

    ExprResult AsmLabel(ParseSimpleAsm(&Loc));

    ExprResult AsmLabel(ParseSimpleAsm(/*ForAsmLabel*/ true, &Loc));

    if (AsmLabel.isInvalid()) {

      SkipUntil(tok::semi, StopBeforeMatch);

      return true;

clang/lib/Parse/ParseDeclCXX.cpp

+1 −1
Original line number Diff line number Diff line
@@ -2325,7 +2325,7 @@ bool Parser::ParseCXXMemberDeclaratorBeforeInitializer( 
  // If a simple-asm-expr is present, parse it.

  if (Tok.is(tok::kw_asm)) {

    SourceLocation Loc;

    ExprResult AsmLabel(ParseSimpleAsm(&Loc));

    ExprResult AsmLabel(ParseSimpleAsm(/*ForAsmLabel*/ true, &Loc));

    if (AsmLabel.isInvalid())

      SkipUntil(tok::comma, StopAtSemi | StopBeforeMatch);

clang/lib/Parse/ParseExprCXX.cpp

+1 −1
Original line number Diff line number Diff line
@@ -2017,7 +2017,7 @@ Sema::ConditionResult Parser::ParseCXXCondition(StmtResult *InitStmt, 
  // simple-asm-expr[opt]

  if (Tok.is(tok::kw_asm)) {

    SourceLocation Loc;

    ExprResult AsmLabel(ParseSimpleAsm(&Loc));

    ExprResult AsmLabel(ParseSimpleAsm(/*ForAsmLabel*/ true, &Loc));

    if (AsmLabel.isInvalid()) {

      SkipUntil(tok::semi, StopAtSemi);

      return Sema::ConditionError();