зеркало из https://github.com/microsoft/clang-1.git
Don't warn for empty 'if' body if there is a macro that expands to nothing, e.g:
if (condition)
CALL(0); // empty macro but don't warn for empty body.
Fixes rdar://8436021.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@119838 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Argyrios Kyrtzidis
Родитель
b95cfe4bb0
Коммит
a25b6a4b43
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@ -651,10 +651,19 @@ class IfStmt : public Stmt {
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SourceLocation IfLoc;
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SourceLocation ElseLoc;
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/// \brief True if we have code like:
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/// @code
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/// #define CALL(x)
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/// if (condition)
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/// CALL(0);
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/// @endcode
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bool MacroExpandedInThenStmt;
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public:
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IfStmt(ASTContext &C, SourceLocation IL, VarDecl *var, Expr *cond,
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Stmt *then, SourceLocation EL = SourceLocation(), Stmt *elsev = 0);
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Stmt *then, SourceLocation EL = SourceLocation(), Stmt *elsev = 0,
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bool macroExpandedInThenStmt = false);
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/// \brief Build an empty if/then/else statement
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explicit IfStmt(EmptyShell Empty) : Stmt(IfStmtClass, Empty) { }
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@ -686,6 +695,8 @@ public:
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SourceLocation getElseLoc() const { return ElseLoc; }
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void setElseLoc(SourceLocation L) { ElseLoc = L; }
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bool hasMacroExpandedInThenStmt() const { return MacroExpandedInThenStmt; }
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virtual SourceRange getSourceRange() const {
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if (SubExprs[ELSE])
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return SourceRange(IfLoc, SubExprs[ELSE]->getLocEnd());
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@ -702,6 +713,9 @@ public:
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// over the initialization expression referenced by the condition variable.
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virtual child_iterator child_begin();
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virtual child_iterator child_end();
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friend class ASTStmtReader;
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friend class ASTStmtWriter;
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};
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/// SwitchStmt - This represents a 'switch' stmt.
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@ -47,6 +47,7 @@ class PPCallbacks;
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class CodeCompletionHandler;
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class DirectoryLookup;
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class PreprocessingRecord;
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class PPMacroExpansionTrap;
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/// Preprocessor - This object engages in a tight little dance with the lexer to
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/// efficiently preprocess tokens. Lexers know only about tokens within a
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@ -110,6 +111,11 @@ class Preprocessor {
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/// DisableMacroExpansion - True if macro expansion is disabled.
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bool DisableMacroExpansion : 1;
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/// \brief This is set to true when a macro is expanded.
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/// Used by PPMacroExpansionTrap.
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bool MacroExpansionFlag : 1;
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friend class PPMacroExpansionTrap;
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/// \brief Whether we have already loaded macros from the external source.
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mutable bool ReadMacrosFromExternalSource : 1;
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@ -1029,6 +1035,17 @@ public:
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virtual bool HandleComment(Preprocessor &PP, SourceRange Comment) = 0;
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};
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/// \brief RAII class that determines when any macro expansion has occurred
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/// between the time the instance was created and the time it was
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/// queried.
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class PPMacroExpansionTrap {
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Preprocessor &PP;
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public:
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PPMacroExpansionTrap(Preprocessor &PP) : PP(PP) { reset(); }
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bool hasMacroExpansionOccured() const { return PP.MacroExpansionFlag; }
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void reset() { PP.MacroExpansionFlag = false; }
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};
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} // end namespace clang
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#endif
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@ -1199,7 +1199,8 @@ private:
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bool ParseParenExprOrCondition(ExprResult &ExprResult,
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Decl *&DeclResult,
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SourceLocation Loc,
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bool ConvertToBoolean);
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bool ConvertToBoolean,
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bool *MacroExpandedAfterRParen = 0);
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StmtResult ParseIfStatement(AttributeList *Attr);
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StmtResult ParseSwitchStatement(AttributeList *Attr);
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StmtResult ParseWhileStatement(AttributeList *Attr);
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@ -1590,7 +1590,7 @@ public:
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bool HasUnusedAttr);
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StmtResult ActOnIfStmt(SourceLocation IfLoc,
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FullExprArg CondVal, Decl *CondVar,
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Stmt *ThenVal,
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Stmt *ThenVal, bool MacroExpandedInThenStmt,
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SourceLocation ElseLoc, Stmt *ElseVal);
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StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
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Expr *Cond,
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@ -470,8 +470,10 @@ CXXTryStmt::CXXTryStmt(SourceLocation tryLoc, Stmt *tryBlock,
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}
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IfStmt::IfStmt(ASTContext &C, SourceLocation IL, VarDecl *var, Expr *cond,
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Stmt *then, SourceLocation EL, Stmt *elsev)
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: Stmt(IfStmtClass), IfLoc(IL), ElseLoc(EL)
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Stmt *then, SourceLocation EL, Stmt *elsev,
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bool macroExpandedInThenStmt)
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: Stmt(IfStmtClass), IfLoc(IL), ElseLoc(EL),
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MacroExpandedInThenStmt(macroExpandedInThenStmt)
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{
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setConditionVariable(C, var);
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SubExprs[COND] = reinterpret_cast<Stmt*>(cond);
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@ -176,6 +176,7 @@ bool Preprocessor::isNextPPTokenLParen() {
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/// expanded as a macro, handle it and return the next token as 'Identifier'.
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bool Preprocessor::HandleMacroExpandedIdentifier(Token &Identifier,
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MacroInfo *MI) {
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MacroExpansionFlag = true;
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if (Callbacks) Callbacks->MacroExpands(Identifier, MI);
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// If this is a macro expansion in the "#if !defined(x)" line for the file,
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@ -538,7 +538,8 @@ StmtResult Parser::ParseCompoundStatementBody(bool isStmtExpr) {
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bool Parser::ParseParenExprOrCondition(ExprResult &ExprResult,
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Decl *&DeclResult,
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SourceLocation Loc,
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bool ConvertToBoolean) {
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bool ConvertToBoolean,
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bool *MacroExpandedAfterRParen) {
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bool ParseError = false;
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SourceLocation LParenLoc = ConsumeParen();
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@ -567,7 +568,14 @@ bool Parser::ParseParenExprOrCondition(ExprResult &ExprResult,
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}
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// Otherwise the condition is valid or the rparen is present.
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// Catch a macro expansion after ')'. This is used to know that there is a
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// macro for 'if' body and not warn for empty body if the macro is empty.
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PPMacroExpansionTrap MacroExpansionTrap(PP);
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MatchRHSPunctuation(tok::r_paren, LParenLoc);
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if (MacroExpandedAfterRParen)
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*MacroExpandedAfterRParen = MacroExpansionTrap.hasMacroExpansionOccured();
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return false;
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}
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@ -610,7 +618,9 @@ StmtResult Parser::ParseIfStatement(AttributeList *Attr) {
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// Parse the condition.
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ExprResult CondExp;
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Decl *CondVar = 0;
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if (ParseParenExprOrCondition(CondExp, CondVar, IfLoc, true))
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bool MacroExpandedInThenStmt;
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if (ParseParenExprOrCondition(CondExp, CondVar, IfLoc, true,
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&MacroExpandedInThenStmt))
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return StmtError();
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FullExprArg FullCondExp(Actions.MakeFullExpr(CondExp.get()));
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@ -694,7 +704,7 @@ StmtResult Parser::ParseIfStatement(AttributeList *Attr) {
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ElseStmt = Actions.ActOnNullStmt(ElseStmtLoc);
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return Actions.ActOnIfStmt(IfLoc, FullCondExp, CondVar, ThenStmt.get(),
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ElseLoc, ElseStmt.get());
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MacroExpandedInThenStmt, ElseLoc, ElseStmt.get());
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}
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/// ParseSwitchStatement
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@ -282,8 +282,8 @@ Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II,
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StmtResult
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Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar,
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Stmt *thenStmt, SourceLocation ElseLoc,
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Stmt *elseStmt) {
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Stmt *thenStmt, bool MacroExpandedInThenStmt,
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SourceLocation ElseLoc, Stmt *elseStmt) {
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ExprResult CondResult(CondVal.release());
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VarDecl *ConditionVar = 0;
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@ -304,17 +304,23 @@ Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar,
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// if (condition);
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// do_stuff();
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//
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// NOTE: Do not emit this warning if the body is expanded from a macro.
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if (!elseStmt) {
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if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt))
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if (!stmt->getLocStart().isMacroID())
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// But do not warn if the body is a macro that expands to nothing, e.g:
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//
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// #define CALL(x)
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// if (condition)
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// CALL(0);
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//
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if (!MacroExpandedInThenStmt)
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Diag(stmt->getSemiLoc(), diag::warn_empty_if_body);
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}
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DiagnoseUnusedExprResult(elseStmt);
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return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr,
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thenStmt, ElseLoc, elseStmt));
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thenStmt, ElseLoc, elseStmt,
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MacroExpandedInThenStmt));
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}
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/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have
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@ -772,9 +772,11 @@ public:
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/// By default, performs semantic analysis to build the new statement.
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/// Subclasses may override this routine to provide different behavior.
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StmtResult RebuildIfStmt(SourceLocation IfLoc, Sema::FullExprArg Cond,
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VarDecl *CondVar, Stmt *Then,
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VarDecl *CondVar, Stmt *Then,
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bool MacroExpandedInThenStmt,
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SourceLocation ElseLoc, Stmt *Else) {
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return getSema().ActOnIfStmt(IfLoc, Cond, CondVar, Then, ElseLoc, Else);
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return getSema().ActOnIfStmt(IfLoc, Cond, CondVar, Then,
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MacroExpandedInThenStmt, ElseLoc, Else);
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}
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/// \brief Start building a new switch statement.
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@ -3692,7 +3694,7 @@ TreeTransform<Derived>::TransformIfStmt(IfStmt *S) {
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return SemaRef.Owned(S);
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return getDerived().RebuildIfStmt(S->getIfLoc(), FullCond, ConditionVar,
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Then.get(),
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Then.get(), S->hasMacroExpandedInThenStmt(),
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S->getElseLoc(), Else.get());
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}
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@ -256,6 +256,7 @@ void ASTStmtReader::VisitIfStmt(IfStmt *S) {
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S->setElse(Reader.ReadSubStmt());
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S->setIfLoc(ReadSourceLocation(Record, Idx));
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S->setElseLoc(ReadSourceLocation(Record, Idx));
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S->MacroExpandedInThenStmt = Record[Idx++];
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}
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void ASTStmtReader::VisitSwitchStmt(SwitchStmt *S) {
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@ -228,6 +228,7 @@ void ASTStmtWriter::VisitIfStmt(IfStmt *S) {
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Writer.AddStmt(S->getElse());
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Writer.AddSourceLocation(S->getIfLoc(), Record);
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Writer.AddSourceLocation(S->getElseLoc(), Record);
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Record.push_back(S->MacroExpandedInThenStmt);
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Code = serialization::STMT_IF;
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}
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@ -16,9 +16,20 @@ void f3() {
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// Don't warn about an empty body if is expanded from a macro.
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void f4(int i) {
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#define BODY ;
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#define BODY(x)
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if (i == i) // expected-warning{{self-comparison always evaluates to true}}
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BODY
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BODY(0);
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#undef BODY
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}
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template <typename T>
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void tf() {
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#define BODY(x)
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if (0)
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BODY(0);
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#undef BODY
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}
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void f5() {
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tf<int>();
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}
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