From 4fd910a096532fed2552c67bceabe237a9e3c7d6 Mon Sep 17 00:00:00 2001 From: Luboš Luňák Date: Sat, 2 Feb 2013 22:59:17 +0100 Subject: tutorial examples for writing new Clang plugin actions http://wiki.documentfoundation.org/Clang_plugins Change-Id: Ieb4fc186490e81ab961c094ca0a7fcdabc0f348f --- compilerplugins/clang/store/tutorial/tutorial1.cxx | 65 +++++++++++++++ compilerplugins/clang/store/tutorial/tutorial1.hxx | 38 +++++++++ .../clang/store/tutorial/tutorial1_example.cxx | 18 +++++ compilerplugins/clang/store/tutorial/tutorial2.cxx | 92 ++++++++++++++++++++++ compilerplugins/clang/store/tutorial/tutorial2.hxx | 37 +++++++++ .../clang/store/tutorial/tutorial2_example.cxx | 15 ++++ compilerplugins/clang/store/tutorial/tutorial3.cxx | 74 +++++++++++++++++ compilerplugins/clang/store/tutorial/tutorial3.hxx | 39 +++++++++ 8 files changed, 378 insertions(+) create mode 100644 compilerplugins/clang/store/tutorial/tutorial1.cxx create mode 100644 compilerplugins/clang/store/tutorial/tutorial1.hxx create mode 100644 compilerplugins/clang/store/tutorial/tutorial1_example.cxx create mode 100644 compilerplugins/clang/store/tutorial/tutorial2.cxx create mode 100644 compilerplugins/clang/store/tutorial/tutorial2.hxx create mode 100644 compilerplugins/clang/store/tutorial/tutorial2_example.cxx create mode 100644 compilerplugins/clang/store/tutorial/tutorial3.cxx create mode 100644 compilerplugins/clang/store/tutorial/tutorial3.hxx (limited to 'compilerplugins/clang/store/tutorial') diff --git a/compilerplugins/clang/store/tutorial/tutorial1.cxx b/compilerplugins/clang/store/tutorial/tutorial1.cxx new file mode 100644 index 000000000000..fa1ec44e351d --- /dev/null +++ b/compilerplugins/clang/store/tutorial/tutorial1.cxx @@ -0,0 +1,65 @@ +/* + * This file is part of the LibreOffice project. + * + * Based on LLVM/Clang. + * + * This file is distributed under the University of Illinois Open Source + * License. See LICENSE.TXT for details. + * + */ + +#include "tutorial1.hxx" + +/* +This is a compile check. + +Checks all return statements and warns if they return literal false (i.e. 'return false'). +*/ + +namespace loplugin +{ + +// Ctor, nothing special, pass the argument(s). +Tutorial1::Tutorial1( ASTContext& context ) + : Plugin( context ) + { + } + +// Perform the actual action. +void Tutorial1::run() + { + // Traverse the whole AST of the translation unit (i.e. examine the whole source file). + // The Clang AST helper class will call VisitReturnStmt for every return statement. + TraverseDecl( context.getTranslationUnitDecl()); + } + +// This function is called for every return statement. +// Returning true means to continue with examining the AST, false means to stop (just always return true). +bool Tutorial1::VisitReturnStmt( ReturnStmt* returnstmt ) + { + // Helper function from the LO base plugin class, call at the very beginning to ignore sources + // that should not be processed (e.g. system headers). + if( ignoreLocation( returnstmt )) + return true; + // Get the expression in the return statement (see ReturnStmt API docs). + const Expr* expression = returnstmt->getRetValue(); + if( expression == NULL ) + return true; // plain 'return;' without expression + // Check if the expression is a bool literal (Clang uses dyn_cast<> instead of dynamic_cast<>). + if( const CXXBoolLiteralExpr* boolliteral = dyn_cast< CXXBoolLiteralExpr >( expression )) + { // It is. + if( boolliteral->getValue() == false ) // Is it 'return false;' ? (See CXXBoolLiteralExpr API docs) + { // Ok, warn, use LO plugin helper function. + report( DiagnosticsEngine::Warning, // It's just a warning. + "returning false", // the message + boolliteral->getLocStart()) // and the exact position where the message should point + << returnstmt->getSourceRange(); // and the full return statement to highlight (optional) + } + } + return true; + } + +// Register the plugin action with the LO plugin handling. +static Plugin::Registration< Tutorial1 > X( "tutorial1" ); + +} // namespace diff --git a/compilerplugins/clang/store/tutorial/tutorial1.hxx b/compilerplugins/clang/store/tutorial/tutorial1.hxx new file mode 100644 index 000000000000..0f5127db65a8 --- /dev/null +++ b/compilerplugins/clang/store/tutorial/tutorial1.hxx @@ -0,0 +1,38 @@ +/* + * This file is part of the LibreOffice project. + * + * Based on LLVM/Clang. + * + * This file is distributed under the University of Illinois Open Source + * License. See LICENSE.TXT for details. + * + */ + +#ifndef TUTORIAL1_H +#define TUTORIAL1_H + +#include "plugin.hxx" + +namespace loplugin +{ + +// The class implementing the plugin action. +class Tutorial1 + // Inherits from the Clang class that will allow examing the Clang AST tree (i.e. syntax tree). + : public RecursiveASTVisitor< Tutorial1 > + // And the base class for LO Clang plugins. + , public Plugin + { + public: + // Ctor, nothing special. + Tutorial1( ASTContext& context ); + // The function that will be called to perform the actual action. + virtual void run(); + // Function from Clang, it will be called for every return statement in the source. + bool VisitReturnStmt( ReturnStmt* returnstmt ); + }; + +} // namespace + +#endif // POSTFIXINCREMENTFIX_H + diff --git a/compilerplugins/clang/store/tutorial/tutorial1_example.cxx b/compilerplugins/clang/store/tutorial/tutorial1_example.cxx new file mode 100644 index 000000000000..ca4c768fdd50 --- /dev/null +++ b/compilerplugins/clang/store/tutorial/tutorial1_example.cxx @@ -0,0 +1,18 @@ +// This is just an example file to see what AST looks like for return statements. +// To the the AST, run : +// clang++ -fsyntax-only -Xclang -ast-dump tutorial1_example.cxx + +void f() + { + return; + } + +bool g() + { + return false; + } + +bool h() + { + return 3 > 2; + } diff --git a/compilerplugins/clang/store/tutorial/tutorial2.cxx b/compilerplugins/clang/store/tutorial/tutorial2.cxx new file mode 100644 index 000000000000..d5fc60b822a3 --- /dev/null +++ b/compilerplugins/clang/store/tutorial/tutorial2.cxx @@ -0,0 +1,92 @@ +/* + * This file is part of the LibreOffice project. + * + * Based on LLVM/Clang. + * + * This file is distributed under the University of Illinois Open Source + * License. See LICENSE.TXT for details. + * + */ + +#include "tutorial2.hxx" + +/* +This is a compile check. + +Warns about if statements with a comparison followed by literal return false: +if( a == 1 ) + return false; +*/ + +namespace loplugin +{ + +Tutorial2::Tutorial2( ASTContext& context ) + : Plugin( context ) + { + } + +void Tutorial2::run() + { + // The Clang AST helper class will call VisitIfStmt for every if statement. + TraverseDecl( context.getTranslationUnitDecl()); + } + +// This function is called for every if statement. +bool Tutorial2::VisitIfStmt( IfStmt* ifstmt ) + { + if( ignoreLocation( ifstmt )) + return true; + // Check if the condition of the if statement is a binary operator. + if( const BinaryOperator* oper = dyn_cast< BinaryOperator >( ifstmt->getCond())) + { + // And if it's operator==. + if( oper->getOpcode() == BO_EQ ) + { + // Now check if the sub-statement is 'return false'. + const Stmt* warn = NULL; // The return statement (for the warning message). + // Check if the sub-statement is directly 'return false;'. + if( isReturnFalse( ifstmt->getThen())) + warn = ifstmt->getThen(); + // Check if the sub-statement is '{ return false; }' + else if( CompoundStmt* compound = dyn_cast< CompoundStmt >( ifstmt->getThen())) + { + if( compound->size() == 1 ) // one statement + if( isReturnFalse( *compound->body_begin())) // check the one sub-statement + warn = *compound->body_begin(); + } + if( warn != NULL ) // there is a return statement to warn about. + { + report( DiagnosticsEngine::Warning, + "returning false after if with equality comparison", + cast< ReturnStmt >( warn )->getRetValue()->getLocStart()) // the 'false' in the return + << warn->getSourceRange(); + // Also add a note showing the if statement. + report( DiagnosticsEngine::Note, + "the if statement is here", + ifstmt->getLocStart()); + } + } + } + return true; + } + +bool Tutorial2::isReturnFalse( const Stmt* stmt ) + { + // Is it return statement? + if( const ReturnStmt* returnstmt = dyn_cast< ReturnStmt >( stmt )) + { + // dyn_cast_or_null<> can also be passed NULL, unlike dyn_cast<> + if( const CXXBoolLiteralExpr* boolliteral = dyn_cast_or_null< CXXBoolLiteralExpr >( returnstmt->getRetValue())) + { + if( boolliteral->getValue() == false ) + return true; + } + } + return false; + } + +// Register the plugin action with the LO plugin handling. +static Plugin::Registration< Tutorial2 > X( "tutorial2" ); + +} // namespace diff --git a/compilerplugins/clang/store/tutorial/tutorial2.hxx b/compilerplugins/clang/store/tutorial/tutorial2.hxx new file mode 100644 index 000000000000..97c56bad195b --- /dev/null +++ b/compilerplugins/clang/store/tutorial/tutorial2.hxx @@ -0,0 +1,37 @@ +/* + * This file is part of the LibreOffice project. + * + * Based on LLVM/Clang. + * + * This file is distributed under the University of Illinois Open Source + * License. See LICENSE.TXT for details. + * + */ + +#ifndef TUTORIAL2_H +#define TUTORIAL2_H + +#include "plugin.hxx" + +namespace loplugin +{ + +// The same like for Tutorial1. +class Tutorial2 + : public RecursiveASTVisitor< Tutorial2 > + , public Plugin + { + public: + Tutorial2( ASTContext& context ); + virtual void run(); + // Will be called for every if statement. + bool VisitIfStmt( IfStmt* ifstmt ); + private: + // Helper function to check if the statement is 'return false;'. + bool isReturnFalse( const Stmt* stmt ); + }; + +} // namespace + +#endif // POSTFIXINCREMENTFIX_H + diff --git a/compilerplugins/clang/store/tutorial/tutorial2_example.cxx b/compilerplugins/clang/store/tutorial/tutorial2_example.cxx new file mode 100644 index 000000000000..d3c14ab7c13c --- /dev/null +++ b/compilerplugins/clang/store/tutorial/tutorial2_example.cxx @@ -0,0 +1,15 @@ +// This is just an example file to see what AST looks like for return statements. +// To the the AST, run : +// clang++ -fsyntax-only -Xclang -ast-dump tutorial1_example.cxx + +bool g() + { + if( 1 == 2 ) + return false; + if( 1 == 2 ) + { + return false; + } + if( true ) + return false; + } diff --git a/compilerplugins/clang/store/tutorial/tutorial3.cxx b/compilerplugins/clang/store/tutorial/tutorial3.cxx new file mode 100644 index 000000000000..e0589f64b671 --- /dev/null +++ b/compilerplugins/clang/store/tutorial/tutorial3.cxx @@ -0,0 +1,74 @@ +/* + * This file is part of the LibreOffice project. + * + * Based on LLVM/Clang. + * + * This file is distributed under the University of Illinois Open Source + * License. See LICENSE.TXT for details. + * + */ + +#include "tutorial3.hxx" + +/* +This is a rewriter. + +It looks for if statements with a comparison followed by literal return false +and modifies the return statements to 'return maybereturntrue;' +*/ + +namespace loplugin +{ + +// Ctor, pass arguments. +Tutorial3::Tutorial3( ASTContext& context, Rewriter& rewriter ) + : RewritePlugin( context, rewriter ) + { + } + +void Tutorial3::run() + { + TraverseDecl( context.getTranslationUnitDecl()); + } + +bool Tutorial3::VisitIfStmt( IfStmt* ifstmt ) + { + if( ignoreLocation( ifstmt )) + return true; + if( const BinaryOperator* oper = dyn_cast< BinaryOperator >( ifstmt->getCond())) + { + if( oper->getOpcode() == BO_EQ ) + { + // Modify the sub-statement if it is 'return false'. + modifyReturnFalse( ifstmt->getThen()); + // Modify the sub-statement if it is '{ return false; }'. + if( CompoundStmt* compound = dyn_cast< CompoundStmt >( ifstmt->getThen())) + { + if( compound->size() == 1 ) // one statement + modifyReturnFalse( *compound->body_begin()); + } + } + } + return true; + } + +void Tutorial3::modifyReturnFalse( const Stmt* stmt ) + { + // Is it return statement? + if( const ReturnStmt* returnstmt = dyn_cast< ReturnStmt >( stmt )) + { + // dyn_cast_or_null<> can also be passed NULL, unlike dyn_cast<> + if( const CXXBoolLiteralExpr* boolliteral = dyn_cast_or_null< CXXBoolLiteralExpr >( returnstmt->getRetValue())) + { + if( boolliteral->getValue() == false ) + { // It is, modify the false to true using LO plugin helper function. + replaceText( boolliteral->getSourceRange(), "maybereturntrue" ); + } + } + } + } + +// Register the plugin action with the LO plugin handling. +static Plugin::Registration< Tutorial3 > X( "tutorial3" ); + +} // namespace diff --git a/compilerplugins/clang/store/tutorial/tutorial3.hxx b/compilerplugins/clang/store/tutorial/tutorial3.hxx new file mode 100644 index 000000000000..69747ee8cf14 --- /dev/null +++ b/compilerplugins/clang/store/tutorial/tutorial3.hxx @@ -0,0 +1,39 @@ +/* + * This file is part of the LibreOffice project. + * + * Based on LLVM/Clang. + * + * This file is distributed under the University of Illinois Open Source + * License. See LICENSE.TXT for details. + * + */ + +#ifndef TUTORIAL3_H +#define TUTORIAL3_H + +#include "plugin.hxx" + +namespace loplugin +{ + +// Similar like for Tutorial2, but this time the base class is RewritePlugin. +class Tutorial3 + : public RecursiveASTVisitor< Tutorial3 > + , public RewritePlugin + { + public: + // One more argument for ctor. + Tutorial3( ASTContext& context, Rewriter& rewriter ); + virtual void run(); + // Will be called for every if statement. + bool VisitIfStmt( IfStmt* ifstmt ); + private: + // Helper function to check if the statement is 'return false;' and + // modify it if yes. + void modifyReturnFalse( const Stmt* stmt ); + }; + +} // namespace + +#endif // POSTFIXINCREMENTFIX_H + -- cgit v1.2.3