From 1ecb41c09b7d81b6ad0d9934ede8464a5c142b2c Mon Sep 17 00:00:00 2001 From: Serge Pavlov Date: Tue, 2 Dec 2014 11:06:09 +0000 Subject: [PATCH] Emit warning if define or undef reserved identifier or keyword. Summary: This change implements warnings if macro name is identical to a keyword or reserved identifier. The warnings are different depending on the "danger" of the operation. Defining macro that replaces a keyword is on by default. Other cases produce warning that is off by default but can be turned on using option -Wreserved-id-macro. This change fixes PR11488. Reviewers: rnk Reviewed By: rnk Subscribers: rnk, cfe-commits Differential Revision: http://reviews.llvm.org/D6194 llvm-svn: 223114 --- clang/include/clang/Basic/DiagnosticGroups.td | 2 + clang/include/clang/Basic/DiagnosticLexKinds.td | 8 +++ clang/include/clang/Basic/IdentifierTable.h | 3 + clang/lib/Basic/IdentifierTable.cpp | 29 ++++++++- clang/lib/Lex/PPDirectives.cpp | 69 ++++++++++++++++++++++ clang/test/PCH/single-token-macro.c | 2 + .../Preprocessor/cxx_oper_keyword_ms_compat.cpp | 2 + clang/test/Sema/thread-specifier.c | 2 + 8 files changed, 115 insertions(+), 2 deletions(-) diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td index af0b948..34609b2 100644 --- a/clang/include/clang/Basic/DiagnosticGroups.td +++ b/clang/include/clang/Basic/DiagnosticGroups.td @@ -337,6 +337,8 @@ def : DiagGroup<"sequence-point", [Unsequenced]>; // Preprocessor warnings. def AmbiguousMacro : DiagGroup<"ambiguous-macro">; +def KeywordAsMacro : DiagGroup<"keyword-macro">; +def ReservedIdAsMacro : DiagGroup<"reserved-id-macro">; // Just silence warnings about -Wstrict-aliasing for now. def : DiagGroup<"strict-aliasing=0">; diff --git a/clang/include/clang/Basic/DiagnosticLexKinds.td b/clang/include/clang/Basic/DiagnosticLexKinds.td index 2fcfa02..5eb9e659 100644 --- a/clang/include/clang/Basic/DiagnosticLexKinds.td +++ b/clang/include/clang/Basic/DiagnosticLexKinds.td @@ -290,6 +290,14 @@ def note_pp_ambiguous_macro_chosen : Note< "expanding this definition of %0">; def note_pp_ambiguous_macro_other : Note< "other definition of %0">; +def warn_pp_macro_hides_keyword : Warning< + "keyword or reserved identifier is hidden by macro definition">, + InGroup; +def warn_pp_macro_is_reserved_id : Warning< + "macro name is a keyword or reserved identifier">, InGroup; +def warn_pp_defundef_reserved_ident : Warning< + "reserved identifier is used as macro name">, DefaultIgnore, + InGroup; def pp_invalid_string_literal : Warning< "invalid string literal, ignoring final '\\'">; diff --git a/clang/include/clang/Basic/IdentifierTable.h b/clang/include/clang/Basic/IdentifierTable.h index ed92339..1de9dd1 100644 --- a/clang/include/clang/Basic/IdentifierTable.h +++ b/clang/include/clang/Basic/IdentifierTable.h @@ -249,6 +249,9 @@ public: } bool isCPlusPlusOperatorKeyword() const { return IsCPPOperatorKeyword; } + /// \brief Return true if this token is a keyword in the specified language. + bool isKeyword(const LangOptions &LangOpts); + /// getFETokenInfo/setFETokenInfo - The language front-end is allowed to /// associate arbitrary metadata with this token. template diff --git a/clang/lib/Basic/IdentifierTable.cpp b/clang/lib/Basic/IdentifierTable.cpp index dd09704..613b43f 100644 --- a/clang/lib/Basic/IdentifierTable.cpp +++ b/clang/lib/Basic/IdentifierTable.cpp @@ -122,7 +122,7 @@ namespace { /// \brief Translates flags as specified in TokenKinds.def into keyword status /// in the given language standard. -static KeywordStatus GetKeywordStatus(const LangOptions &LangOpts, +static KeywordStatus getKeywordStatus(const LangOptions &LangOpts, unsigned Flags) { if (Flags == KEYALL) return KS_Enabled; if (LangOpts.CPlusPlus && (Flags & KEYCXX)) return KS_Enabled; @@ -151,7 +151,7 @@ static KeywordStatus GetKeywordStatus(const LangOptions &LangOpts, static void AddKeyword(StringRef Keyword, tok::TokenKind TokenCode, unsigned Flags, const LangOptions &LangOpts, IdentifierTable &Table) { - KeywordStatus AddResult = GetKeywordStatus(LangOpts, Flags); + KeywordStatus AddResult = getKeywordStatus(LangOpts, Flags); // Don't add this keyword under MSVCCompat. if (LangOpts.MSVCCompat && (Flags & KEYNOMS)) @@ -209,6 +209,31 @@ void IdentifierTable::AddKeywords(const LangOptions &LangOpts) { LangOpts, *this); } +/// \brief Checks if the specified token kind represents a keyword in the +/// specified language. +/// \returns Status of the keyword in the language. +static KeywordStatus getTokenKwStatus(const LangOptions &LangOpts, + tok::TokenKind K) { + switch (K) { +#define KEYWORD(NAME, FLAGS) \ + case tok::kw_##NAME: return getKeywordStatus(LangOpts, FLAGS); +#include "clang/Basic/TokenKinds.def" + default: return KS_Disabled; + } +} + +/// \brief Returns true if the identifier represents a keyword in the +/// specified language. +bool IdentifierInfo::isKeyword(const LangOptions &LangOpts) { + switch (getTokenKwStatus(LangOpts, getTokenID())) { + case KS_Enabled: + case KS_Extension: + return true; + default: + return false; + } +} + tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const { // We use a perfect hash function here involving the length of the keyword, // the first and third character. For preprocessor ID's there are no diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp index 0a46663..16b86b7 100644 --- a/clang/lib/Lex/PPDirectives.cpp +++ b/clang/lib/Lex/PPDirectives.cpp @@ -100,6 +100,58 @@ void Preprocessor::DiscardUntilEndOfDirective() { } while (Tmp.isNot(tok::eod)); } +/// \brief Enumerates possible cases of #define/#undef a reserved identifier. +enum MacroDiag { + MD_NoWarn, //> Not a reserved identifier + MD_KeywordDef, //> Macro hides keyword, enabled by default + MD_KeywordUndef, //> #undef keyword, enabled by default + MD_WarnStrict //> Other reserved id, disabled by default +}; + +/// \brief Checks if the specified identifier is reserved in the specified +/// language. +/// This function does not check if the identifier is a keyword. +static bool isReservedId(StringRef Text, const LangOptions &Lang) { + // C++ [macro.names], C11 7.1.3: + // All identifiers that begin with an underscore and either an uppercase + // letter or another underscore are always reserved for any use. + if (Text.size() >= 2 && Text[0] == '_' && + (isUppercase(Text[1]) || Text[1] == '_')) + return true; + // C++ [global.names] + // Each name that contains a double underscore ... is reserved to the + // implementation for any use. + if (Lang.CPlusPlus) { + if (Text.find("__") != StringRef::npos) + return true; + } + return false; +} + +static MacroDiag shouldWarnOnMacroDef(Preprocessor &PP, IdentifierInfo *II) { + const LangOptions &Lang = PP.getLangOpts(); + StringRef Text = II->getName(); + if (isReservedId(Text, Lang)) + return MD_WarnStrict; + if (II->isKeyword(Lang)) + return MD_KeywordDef; + if (Lang.CPlusPlus && (Text.equals("override") || Text.equals("final"))) + return MD_KeywordDef; + return MD_NoWarn; +} + +static MacroDiag shouldWarnOnMacroUndef(Preprocessor &PP, IdentifierInfo *II) { + const LangOptions &Lang = PP.getLangOpts(); + if (II->isKeyword(Lang)) + return MD_KeywordUndef; + StringRef Text = II->getName(); + if (Lang.CPlusPlus && (Text.equals("override") || Text.equals("final"))) + return MD_KeywordUndef; + if (isReservedId(Text, Lang)) + return MD_WarnStrict; + return MD_NoWarn; +} + bool Preprocessor::CheckMacroName(Token &MacroNameTok, MacroUse isDefineUndef) { // Missing macro name? if (MacroNameTok.is(tok::eod)) @@ -140,6 +192,23 @@ bool Preprocessor::CheckMacroName(Token &MacroNameTok, MacroUse isDefineUndef) { Diag(MacroNameTok, diag::ext_pp_undef_builtin_macro); } + // Warn if defining/undefining reserved identifier including keywords. + SourceLocation MacroNameLoc = MacroNameTok.getLocation(); + if (!SourceMgr.isInSystemHeader(MacroNameLoc) && + (strcmp(SourceMgr.getBufferName(MacroNameLoc), "") != 0)) { + MacroDiag D = MD_NoWarn; + if (isDefineUndef == MU_Define) + D = shouldWarnOnMacroDef(*this, II); + else if (isDefineUndef == MU_Undef) + D = shouldWarnOnMacroUndef(*this, II); + if (D == MD_KeywordDef) + Diag(MacroNameTok, diag::warn_pp_macro_hides_keyword); + if (D == MD_KeywordUndef) + Diag(MacroNameTok, diag::warn_pp_macro_is_reserved_id); + else if (D == MD_WarnStrict) + Diag(MacroNameTok, diag::warn_pp_defundef_reserved_ident); + } + // Okay, we got a good identifier. return false; } diff --git a/clang/test/PCH/single-token-macro.c b/clang/test/PCH/single-token-macro.c index aa02f65..b077aba 100644 --- a/clang/test/PCH/single-token-macro.c +++ b/clang/test/PCH/single-token-macro.c @@ -12,6 +12,8 @@ #ifndef HEADER #define HEADER +#pragma clang diagnostic ignored "-Wreserved-id-macro" + #ifdef __stdcall // __stdcall is defined as __attribute__((__stdcall__)) for targeting mingw32. #undef __stdcall diff --git a/clang/test/Preprocessor/cxx_oper_keyword_ms_compat.cpp b/clang/test/Preprocessor/cxx_oper_keyword_ms_compat.cpp index 8e1351e..24a3898 100644 --- a/clang/test/Preprocessor/cxx_oper_keyword_ms_compat.cpp +++ b/clang/test/Preprocessor/cxx_oper_keyword_ms_compat.cpp @@ -1,6 +1,8 @@ // RUN: %clang_cc1 %s -E -verify -fms-extensions // expected-no-diagnostics +#pragma clang diagnostic ignored "-Wkeyword-macro" + bool f() { // Check that operators still work before redefining them. #if compl 0 bitand 1 diff --git a/clang/test/Sema/thread-specifier.c b/clang/test/Sema/thread-specifier.c index 3968ae1..71e44c3 100644 --- a/clang/test/Sema/thread-specifier.c +++ b/clang/test/Sema/thread-specifier.c @@ -5,6 +5,8 @@ // RUN: %clang_cc1 -triple i686-pc-linux-gnu -fsyntax-only -Wno-private-extern -verify -pedantic -x c++ %s -DCXX11 -D__thread=thread_local -std=c++11 -Wno-deprecated // RUN: %clang_cc1 -triple i686-pc-linux-gnu -fsyntax-only -Wno-private-extern -verify -pedantic -x c++ %s -DC11 -D__thread=_Thread_local -std=c++11 -Wno-deprecated +#pragma clang diagnostic ignored "-Wkeyword-macro" + #ifdef __cplusplus // In C++, we define __private_extern__ to extern. #undef __private_extern__ -- 2.7.4