From: Richard Smith Date: Thu, 12 Jan 2012 23:53:29 +0000 (+0000) Subject: Improve 0-argument -Wvexing-parse diagnostic by adding notes with fix-its: X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7984de35644701c0d94336da7f2215d4c26d9f5b;p=clang Improve 0-argument -Wvexing-parse diagnostic by adding notes with fix-its: - If the declarator is at the start of a line, and the previous line contained another declarator and ended with a comma, then that comma was probably a typo for a semicolon: int n = 0, m = 1, l = 2, // k = 5; myImportantFunctionCall(); // oops! - If removing the parentheses would correctly initialize the object, then produce a note suggesting that fix. - Otherwise, if there is a simple initializer we can suggest which performs value-initialization, then provide a note suggesting a correction to that initializer. Sema::Declarator now tracks the location of the comma prior to the declarator in the declaration, if there is one, to facilitate providing the note. The code to determine an appropriate initializer from the -Wuninitialized warning has been factored out to allow use in both that and -Wvexing-parse. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148072 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td index 4341dbbfa9..fbd8098a40 100644 --- a/include/clang/Basic/DiagnosticSemaKinds.td +++ b/include/clang/Basic/DiagnosticSemaKinds.td @@ -115,6 +115,12 @@ def warn_decl_in_param_list : Warning< def warn_empty_parens_are_function_decl : Warning< "empty parentheses interpreted as a function declaration">, InGroup; +def note_empty_parens_function_call : Note< + "change this ',' to a ';' to call %0">; +def note_empty_parens_default_ctor : Note< + "remove parentheses to declare a variable">; +def note_empty_parens_zero_initialize : Note< + "replace parentheses with an initializer to declare a variable">; def warn_unused_function : Warning<"unused function %0">, InGroup, DefaultIgnore; def warn_unused_member_function : Warning<"unused member function %0">, diff --git a/include/clang/Sema/DeclSpec.h b/include/clang/Sema/DeclSpec.h index a601210bf4..edc6fd3bc9 100644 --- a/include/clang/Sema/DeclSpec.h +++ b/include/clang/Sema/DeclSpec.h @@ -1468,6 +1468,10 @@ private: /// Extension - true if the declaration is preceded by __extension__. bool Extension : 1; + /// \brief If this is the second or subsequent declarator in this declaration, + /// the location of the comma before this declarator. + SourceLocation CommaLoc; + /// \brief If provided, the source location of the ellipsis used to describe /// this declarator as a parameter pack. SourceLocation EllipsisLoc; @@ -1557,6 +1561,8 @@ public: Attrs.clear(); AsmLabel = 0; InlineParamsUsed = false; + CommaLoc = SourceLocation(); + EllipsisLoc = SourceLocation(); } /// mayOmitIdentifier - Return true if the identifier is either optional or @@ -1846,7 +1852,11 @@ public: void setGroupingParens(bool flag) { GroupingParens = flag; } bool hasGroupingParens() const { return GroupingParens; } - + + bool isFirstDeclarator() const { return !CommaLoc.isValid(); } + SourceLocation getCommaLoc() const { return CommaLoc; } + void setCommaLoc(SourceLocation CL) { CommaLoc = CL; } + bool hasEllipsis() const { return EllipsisLoc.isValid(); } SourceLocation getEllipsisLoc() const { return EllipsisLoc; } void setEllipsisLoc(SourceLocation EL) { EllipsisLoc = EL; } diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h index aa0a7ef957..d570a77936 100644 --- a/include/clang/Sema/Sema.h +++ b/include/clang/Sema/Sema.h @@ -756,6 +756,9 @@ public: bool findMacroSpelling(SourceLocation &loc, StringRef name); + /// \brief Get a string to suggest for zero-initialization of a type. + const char *getFixItZeroInitializerForType(QualType T) const; + ExprResult Owned(Expr* E) { return E; } ExprResult Owned(ExprResult R) { return R; } StmtResult Owned(Stmt* S) { return S; } diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp index be5d5ae54c..032326cea7 100644 --- a/lib/Parse/ParseDecl.cpp +++ b/lib/Parse/ParseDecl.cpp @@ -1138,6 +1138,7 @@ Parser::DeclGroupPtrTy Parser::ParseDeclGroup(ParsingDeclSpec &DS, // Parse the next declarator. D.clear(); + D.setCommaLoc(CommaLoc); // Accept attributes in an init-declarator. In the first declarator in a // declaration, these would be part of the declspec. In subsequent @@ -2665,9 +2666,11 @@ ParseStructDeclaration(DeclSpec &DS, FieldCallback &Fields) { // Read struct-declarators until we find the semicolon. bool FirstDeclarator = true; + SourceLocation CommaLoc; while (1) { ParsingDeclRAIIObject PD(*this); FieldDeclarator DeclaratorInfo(DS); + DeclaratorInfo.D.setCommaLoc(CommaLoc); // Attributes are only allowed here on successive declarators. if (!FirstDeclarator) @@ -2703,7 +2706,7 @@ ParseStructDeclaration(DeclSpec &DS, FieldCallback &Fields) { return; // Consume the comma. - ConsumeToken(); + CommaLoc = ConsumeToken(); FirstDeclarator = false; } diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp index 285dbbbe07..c31c55ba5b 100644 --- a/lib/Parse/ParseDeclCXX.cpp +++ b/lib/Parse/ParseDeclCXX.cpp @@ -2044,6 +2044,7 @@ void Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS, BitfieldSize = true; Init = true; HasInitializer = false; + DeclaratorInfo.setCommaLoc(CommaLoc); // Attributes are only allowed on the second declarator. MaybeParseGNUAttributes(DeclaratorInfo); diff --git a/lib/Parse/Parser.cpp b/lib/Parse/Parser.cpp index d14b9adce2..e09ee79c8c 100644 --- a/lib/Parse/Parser.cpp +++ b/lib/Parse/Parser.cpp @@ -1067,11 +1067,12 @@ void Parser::ParseKNRParamDeclarations(Declarator &D) { if (Tok.isNot(tok::comma)) break; + ParmDeclarator.clear(); + // Consume the comma. - ConsumeToken(); + ParmDeclarator.setCommaLoc(ConsumeToken()); // Parse the next declarator. - ParmDeclarator.clear(); ParseDeclarator(ParmDeclarator); } diff --git a/lib/Sema/AnalysisBasedWarnings.cpp b/lib/Sema/AnalysisBasedWarnings.cpp index 3567b6bbe0..9b3191b027 100644 --- a/lib/Sema/AnalysisBasedWarnings.cpp +++ b/lib/Sema/AnalysisBasedWarnings.cpp @@ -415,42 +415,15 @@ static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) { return false; // Suggest possible initialization (if any). - const char *initialization = 0; QualType VariableTy = VD->getType().getCanonicalType(); - - if (VariableTy->isObjCObjectPointerType() || - VariableTy->isBlockPointerType()) { - // Check if 'nil' is defined. - if (S.PP.getMacroInfo(&S.getASTContext().Idents.get("nil"))) - initialization = " = nil"; - else - initialization = " = 0"; - } - else if (VariableTy->isRealFloatingType()) - initialization = " = 0.0"; - else if (VariableTy->isBooleanType() && S.Context.getLangOptions().CPlusPlus) - initialization = " = false"; - else if (VariableTy->isEnumeralType()) + const char *Init = S.getFixItZeroInitializerForType(VariableTy); + if (!Init) return false; - else if (VariableTy->isPointerType() || VariableTy->isMemberPointerType()) { - if (S.Context.getLangOptions().CPlusPlus0x) - initialization = " = nullptr"; - // Check if 'NULL' is defined. - else if (S.PP.getMacroInfo(&S.getASTContext().Idents.get("NULL"))) - initialization = " = NULL"; - else - initialization = " = 0"; - } - else if (VariableTy->isScalarType()) - initialization = " = 0"; - if (initialization) { - SourceLocation loc = S.PP.getLocForEndOfToken(VD->getLocEnd()); - S.Diag(loc, diag::note_var_fixit_add_initialization) << VD->getDeclName() - << FixItHint::CreateInsertion(loc, initialization); - return true; - } - return false; + SourceLocation Loc = S.PP.getLocForEndOfToken(VD->getLocEnd()); + S.Diag(Loc, diag::note_var_fixit_add_initialization) << VD->getDeclName() + << FixItHint::CreateInsertion(Loc, Init); + return true; } /// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp index dc8d6ec8cf..4dcf1db2cf 100644 --- a/lib/Sema/SemaDecl.cpp +++ b/lib/Sema/SemaDecl.cpp @@ -4921,8 +4921,39 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC, if (!T->isVoidType() && C.Fun.NumArgs == 0 && !C.Fun.isVariadic && !C.Fun.TrailingReturnType && C.Fun.getExceptionSpecType() == EST_None) { - Diag(C.Loc, diag::warn_empty_parens_are_function_decl) - << SourceRange(C.Loc, C.EndLoc); + SourceRange ParenRange(C.Loc, C.EndLoc); + Diag(C.Loc, diag::warn_empty_parens_are_function_decl) << ParenRange; + + // If the declaration looks like: + // T var1, + // f(); + // and name lookup finds a function named 'f', then the ',' was + // probably intended to be a ';'. + if (!D.isFirstDeclarator() && D.getIdentifier()) { + FullSourceLoc Comma(D.getCommaLoc(), SourceMgr); + FullSourceLoc Name(D.getIdentifierLoc(), SourceMgr); + if (Comma.getFileID() != Name.getFileID() || + Comma.getSpellingLineNumber() != Name.getSpellingLineNumber()) { + LookupResult Result(*this, D.getIdentifier(), SourceLocation(), + LookupOrdinaryName); + if (LookupName(Result, S)) + Diag(D.getCommaLoc(), diag::note_empty_parens_function_call) + << FixItHint::CreateReplacement(D.getCommaLoc(), ";") << NewFD; + } + } + const CXXRecordDecl *RD = T->getAsCXXRecordDecl(); + // Empty parens mean value-initialization, and no parens mean default + // initialization. These are equivalent if the default constructor is + // user-provided, or if zero-initialization is a no-op. + if (RD && (RD->isEmpty() || RD->hasUserProvidedDefaultConstructor())) + Diag(C.Loc, diag::note_empty_parens_default_ctor) + << FixItHint::CreateRemoval(ParenRange); + else if (const char *Init = getFixItZeroInitializerForType(T)) + Diag(C.Loc, diag::note_empty_parens_zero_initialize) + << FixItHint::CreateReplacement(ParenRange, Init); + else if (LangOpts.CPlusPlus0x) + Diag(C.Loc, diag::note_empty_parens_zero_initialize) + << FixItHint::CreateReplacement(ParenRange, "{}"); } } diff --git a/lib/Sema/SemaFixItUtils.cpp b/lib/Sema/SemaFixItUtils.cpp index 8e8a46da73..1f17a9e83e 100644 --- a/lib/Sema/SemaFixItUtils.cpp +++ b/lib/Sema/SemaFixItUtils.cpp @@ -158,3 +158,31 @@ bool ConversionFixItGenerator::tryToFixConversion(const Expr *FullExpr, return false; } + +const char *Sema::getFixItZeroInitializerForType(QualType T) const { + // Suggest 'nil' if it's defined and appropriate. + if ((T->isObjCObjectPointerType() || T->isBlockPointerType()) && + PP.getMacroInfo(&getASTContext().Idents.get("nil"))) + return " = nil"; + if (T->isRealFloatingType()) + return " = 0.0"; + if (T->isBooleanType() && LangOpts.CPlusPlus) + return " = false"; + if (T->isPointerType() || T->isMemberPointerType()) { + if (LangOpts.CPlusPlus0x) + return " = nullptr"; + // Check if 'NULL' is defined. + else if (PP.getMacroInfo(&getASTContext().Idents.get("NULL"))) + return " = NULL"; + } + if (T->isEnumeralType()) + return 0; + if (T->isScalarType()) + return " = 0"; + const CXXRecordDecl *RD = T->getAsCXXRecordDecl(); + if (LangOpts.CPlusPlus0x && RD && !RD->hasUserProvidedDefaultConstructor()) + return "{}"; + if (T->isAggregateType()) + return " = {}"; + return 0; +} diff --git a/test/CXX/basic/basic.link/p9.cpp b/test/CXX/basic/basic.link/p9.cpp index c895253c68..680c93db2e 100644 --- a/test/CXX/basic/basic.link/p9.cpp +++ b/test/CXX/basic/basic.link/p9.cpp @@ -6,5 +6,5 @@ namespace N { } // expected-note{{here}} // First bullet: two names with external linkage that refer to // different kinds of entities. void f() { - int N(); // expected-error{{redefinition}} expected-warning{{interpreted as a function declaration}} + int N(); // expected-error{{redefinition}} expected-warning{{interpreted as a function declaration}} expected-note {{replace parentheses with an initializer}} } diff --git a/test/CXX/dcl.dcl/basic.namespace/namespace.udecl/p11.cpp b/test/CXX/dcl.dcl/basic.namespace/namespace.udecl/p11.cpp index b1dcf4d015..99903b57bf 100644 --- a/test/CXX/dcl.dcl/basic.namespace/namespace.udecl/p11.cpp +++ b/test/CXX/dcl.dcl/basic.namespace/namespace.udecl/p11.cpp @@ -12,26 +12,26 @@ namespace test0 { namespace ns { void foo(); } // expected-note {{target of using declaration}} - int foo(); // expected-note {{conflicting declaration}} + int foo(void); // expected-note {{conflicting declaration}} using ns::foo; // expected-error {{target of using declaration conflicts with declaration already in scope}} } namespace test1 { namespace ns { void foo(); } // expected-note {{target of using declaration}} using ns::foo; //expected-note {{using declaration}} - int foo(); // expected-error {{declaration conflicts with target of using declaration already in scope}} + int foo(void); // expected-error {{declaration conflicts with target of using declaration already in scope}} } namespace test2 { namespace ns { void foo(); } // expected-note 2 {{target of using declaration}} void test0() { - int foo(); // expected-note {{conflicting declaration}} expected-warning{{function declaration}} + int foo(void); // expected-note {{conflicting declaration}} using ns::foo; // expected-error {{target of using declaration conflicts with declaration already in scope}} } void test1() { using ns::foo; //expected-note {{using declaration}} - int foo(); // expected-error {{declaration conflicts with target of using declaration already in scope}} expected-warning{{function declaration}} + int foo(void); // expected-error {{declaration conflicts with target of using declaration already in scope}} } } @@ -39,7 +39,7 @@ namespace test3 { namespace ns { void foo(); } // expected-note 2 {{target of using declaration}} class Test0 { void test() { - int foo(); // expected-note {{conflicting declaration}} expected-warning{{function declaration}} + int foo(void); // expected-note {{conflicting declaration}} using ns::foo; // expected-error {{target of using declaration conflicts with declaration already in scope}} } }; @@ -47,7 +47,7 @@ namespace test3 { class Test1 { void test() { using ns::foo; //expected-note {{using declaration}} - int foo(); // expected-error {{declaration conflicts with target of using declaration already in scope}} expected-warning{{function declaration}} + int foo(void); // expected-error {{declaration conflicts with target of using declaration already in scope}} } }; } @@ -56,7 +56,7 @@ namespace test4 { namespace ns { void foo(); } // expected-note 2 {{target of using declaration}} template class Test0 { void test() { - int foo(); // expected-note {{conflicting declaration}} expected-warning{{function declaration}} + int foo(void); // expected-note {{conflicting declaration}} using ns::foo; // expected-error {{target of using declaration conflicts with declaration already in scope}} } }; @@ -64,7 +64,7 @@ namespace test4 { template class Test1 { void test() { using ns::foo; //expected-note {{using declaration}} - int foo(); // expected-error {{declaration conflicts with target of using declaration already in scope}} expected-warning{{function declaration}} + int foo(void); // expected-error {{declaration conflicts with target of using declaration already in scope}} } }; } diff --git a/test/FixIt/fixit-vexing-parse.cpp b/test/FixIt/fixit-vexing-parse.cpp new file mode 100644 index 0000000000..0f0505f983 --- /dev/null +++ b/test/FixIt/fixit-vexing-parse.cpp @@ -0,0 +1,80 @@ +// RUN: %clang_cc1 -verify -x c++ %s +// RUN: %clang_cc1 -fdiagnostics-parseable-fixits -x c++ %s 2>&1 | FileCheck %s + +struct S { + int n; +}; + +struct T { + T(); + int n; +}; + +struct U { + ~U(); + int n; +}; + +struct V { + ~V(); +}; + +struct W : V { +}; + +struct X : U { +}; + +int F1(); +S F2(); + +namespace N { + void test() { + // CHECK: fix-it:"{{.*}}":{34:9-34:11}:" = {}" + S s1(); // expected-warning {{function declaration}} expected-note {{replace parentheses with an initializer}} + + // CHECK: fix-it:"{{.*}}":{38:9-38:10}:";" + // CHECK: fix-it:"{{.*}}":{39:7-39:9}:" = {}" + S s2, // expected-note {{change this ',' to a ';' to call 'F2'}} + F2(); // expected-warning {{function declaration}} expected-note {{replace parentheses with an initializer}} + + // CHECK: fix-it:"{{.*}}":{43:9-43:11}:"" + // CHECK: fix-it:"{{.*}}":{44:9-44:11}:"" + T t1(), // expected-warning {{function declaration}} expected-note {{remove parentheses}} + t2(); // expected-warning {{function declaration}} expected-note {{remove parentheses}} + + // CHECK: fix-it:"{{.*}}":{47:8-47:10}:" = {}" + U u(); // expected-warning {{function declaration}} expected-note {{replace parentheses with an initializer}} + + // CHECK: fix-it:"{{.*}}":{50:8-50:10}:"" + V v(); // expected-warning {{function declaration}} expected-note {{remove parentheses}} + + // CHECK: fix-it:"{{.*}}":{53:8-53:10}:"" + W w(); // expected-warning {{function declaration}} expected-note {{remove parentheses}} + + // TODO: Removing the parens here would not initialize U::n. + // Maybe suggest an " = X()" initializer for this case? + // Maybe suggest removing the parens anyway? + X x(); // expected-warning {{function declaration}} + + // CHECK: fix-it:"{{.*}}":{61:11-61:13}:" = 0" + int n1(); // expected-warning {{function declaration}} expected-note {{replace parentheses with an initializer}} + + // CHECK: fix-it:"{{.*}}":{65:11-65:12}:";" + // CHECK: fix-it:"{{.*}}":{66:7-66:9}:" = 0" + int n2, // expected-note {{change this ',' to a ';' to call 'F1'}} + F1(); // expected-warning {{function declaration}} expected-note {{replace parentheses with an initializer}} + + // CHECK: fix-it:"{{.*}}":{69:13-69:15}:" = 0.0" + double d(); // expected-warning {{function declaration}} expected-note {{replace parentheses with an initializer}} + + typedef void *Ptr; + + // CHECK: fix-it:"{{.*}}":{74:10-74:12}:" = 0" + Ptr p(); // expected-warning {{function declaration}} expected-note {{replace parentheses with an initializer}} + +#define NULL 0 + // CHECK: fix-it:"{{.*}}":{78:10-78:12}:" = NULL" + Ptr p(); // expected-warning {{function declaration}} expected-note {{replace parentheses with an initializer}} + } +} diff --git a/test/SemaCXX/condition.cpp b/test/SemaCXX/condition.cpp index 3d17dc3937..43ee640e0f 100644 --- a/test/SemaCXX/condition.cpp +++ b/test/SemaCXX/condition.cpp @@ -7,7 +7,7 @@ void test() { typedef int arr[10]; while (arr x=0) ; // expected-error {{an array type is not allowed here}} expected-error {{array initializer must be an initializer list}} - while (int f()=0) ; // expected-warning {{interpreted as a function declaration}} expected-error {{a function type is not allowed here}} + while (int f()=0) ; // expected-warning {{interpreted as a function declaration}} expected-note {{initializer}} expected-error {{a function type is not allowed here}} struct S {} s; if (s) ++x; // expected-error {{value of type 'struct S' is not contextually convertible to 'bool'}} diff --git a/test/SemaCXX/conditional-expr.cpp b/test/SemaCXX/conditional-expr.cpp index 3cfddb3a41..4aee913277 100644 --- a/test/SemaCXX/conditional-expr.cpp +++ b/test/SemaCXX/conditional-expr.cpp @@ -96,8 +96,8 @@ void test() (void)(i1 ? BadDerived() : BadBase()); // b2.1 (hierarchy stuff) - const Base constret(); // expected-warning {{interpreted as a function declaration}} - const Derived constder(); // expected-warning {{interpreted as a function declaration}} + extern const Base constret(); + extern const Derived constder(); // should use const overload A a1((i1 ? constret() : Base()).trick()); A a2((i1 ? Base() : constret()).trick()); diff --git a/test/SemaCXX/decl-expr-ambiguity.cpp b/test/SemaCXX/decl-expr-ambiguity.cpp index 3a946c0ffb..f6dbe2f339 100644 --- a/test/SemaCXX/decl-expr-ambiguity.cpp +++ b/test/SemaCXX/decl-expr-ambiguity.cpp @@ -26,15 +26,15 @@ void f() { T(*d)(int(p)); // expected-warning {{parentheses were disambiguated as a function declarator}} expected-note {{previous definition is here}} typedef T(*td)(int(p)); extern T(*tp)(int(p)); - T d3(); // expected-warning {{empty parentheses interpreted as a function declaration}} + T d3(); // expected-warning {{empty parentheses interpreted as a function declaration}} expected-note {{replace parentheses with an initializer}} T d3v(void); typedef T d3t(); extern T f3(); - __typeof(*T()) f4(); // expected-warning {{empty parentheses interpreted as a function declaration}} + __typeof(*T()) f4(); // expected-warning {{empty parentheses interpreted as a function declaration}} expected-note {{replace parentheses with an initializer}} typedef void *V; __typeof(*V()) f5(); T multi1, - multi2(); // expected-warning {{empty parentheses interpreted as a function declaration}} + multi2(); // expected-warning {{empty parentheses interpreted as a function declaration}} expected-note {{replace parentheses with an initializer}} T(d)[5]; // expected-error {{redefinition of 'd'}} typeof(int[])(f) = { 1, 2 }; // expected-error {{extension used}} void(b)(int); @@ -43,6 +43,20 @@ void f() { int(d3(int())); } +struct RAII { + RAII(); + ~RAII(); +}; + +void func(); +namespace N { + void emptyParens() { + RAII raii(); // expected-warning {{function declaration}} expected-note {{remove parentheses to declare a variable}} + int a, b, c, d, e, // expected-note {{change this ',' to a ';' to call 'func'}} + func(); // expected-warning {{function declaration}} expected-note {{replace parentheses with an initializer}} + } +} + class C { }; void fn(int(C)) { } // void fn(int(*fp)(C c)) { } expected-note{{candidate function}} // not: void fn(int C);