transformation of c code to matlab/simulink models approach based on parsing vilmos zsombori...

Transformation of C code to Matlab/Simulink models

Approach based on parsing

Vilmos Zsombori4.01.2005, Shanghai

Vilmos Zsombori 4.01.2005

Motivation

• Considerations:• The amount of source code to be transformed• Transformation patterns• Existence of third party parser generators that allow to automatically generate a

customized parser for a user defined grammar

• Prerequisite of automatic transformation:• Customized lexical analyzer• Customized syntactic analyzer• Implementation of output actions

• Benefits:• The tool would reduce a large amount of transformation time• The automatic transformation is not susceptible to “human” errors• The actions are attached to language structures, in consequence the transformation is

uniform, based on patterns and modeling guidelines• In case of library upgrades, name changes or pattern changes, the model update

requests incomparably less time than the manual approach

• Considerations:• The amount of source code to be transformed• Transformation patterns• Existence of third party parser generators that allow to automatically generate a

customized parser for a user defined grammar

• Prerequisite of automatic transformation:• Customized lexical analyzer• Customized syntactic analyzer• Implementation of output actions

• Benefits:• The tool would reduce a large amount of transformation time• The automatic transformation is not susceptible to “human” errors• The actions are attached to language structures, in consequence the transformation is

uniform, based on patterns and modeling guidelines• In case of library upgrades, name changes or pattern changes, the model update

requests incomparably less time than the manual approach


Approach

Based on lexical and syntactic analysis Automatic parser generation Action specification according to the transformation patterns and the modeling guidelines

Key conceptKey concept

cpp.jj

grammarspecification

parserspecification

actionspecification

Customized parser and code generator

Synthesis(JavaCC)

CPPParser.javaand C2Model.java

General architectureGeneral architecture


cpp.jj


parserspecification

actionspecification


Synthesis(JavaCC)




Lexical and Syntactic analysis (I)

SKIP : { “ ” | “\n” | <“/*” … “/”> }

TOKEN : { <#DECIMAL_LITERAL: ["1"-"9"] (["0"-"9"])*>

| <STRING_LITERAL: "\"" … "\""> … }

TOKEN : { <CONTINUE: "continue">

| <VOLATILE: "volatile">

| <TYPEDEF: "typedef">

| <IF: "if">

| <DO: "do"> … }

TOKEN : { <IDENTIFIER: <LETTER> (<LETTER> | <DIGIT>)*>

| <#LETTER: ["$","A"-"Z","_","a"-"z"]>

| <#DIGIT: ["0"-"9"]> }

Lexical analysis (tokens – regular expressions)Lexical analysis (tokens – regular expressions)


Lexical and Syntactic analysis (II)

translation_unit : external_declaration | translation_unit external_declaration;

external_declaration : function_definition | declaration;

function_definition

: declaration_specifiers declarator declaration_list compound_statement

| declaration_specifiers declarator compound_statement

| declarator declaration_list compound_statement

| declarator compound_statement;

selection_statement

: IF '(' expression ')' statement

| IF '(' expression ')' statement ELSE statement

| SWITCH '(' expression ')' statement;

Syntactic analysis (C grammar)Syntactic analysis (C grammar)


cpp.jj


parserspecification

actionspecification


Synthesis(JavaCC)




Parser generation (I)

• Based on lexical and syntactic descriptions

• Available parser generators:

• Lex + Yacc• Generation of C code for the parser• Tool freely available for Linux but NOT for Windows• Needs a C compiler (gcc)

• JavaCC• Generation of Java code for the parser• Needs a Java compiler and a Java Virtual Machine at runtime• Both, JDK and JavaCC are FREE-ly available• The generated parser is platform independent

• The current work is based on JavaCC

• Based on lexical and syntactic descriptions

• Available parser generators:

• Lex + Yacc• Generation of C code for the parser• Tool freely available for Linux but NOT for Windows• Needs a C compiler (gcc)

• JavaCC• Generation of Java code for the parser• Needs a Java compiler and a Java Virtual Machine at runtime• Both, JDK and JavaCC are FREE-ly available• The generated parser is platform independent

• The current work is based on JavaCC


Parser generation (II)

LexicalAnalyzer

SyntaxAnalyzer

JavaCCCompiler

JavaCC Sourcecpp.jj

CPPParserTokens.javaCPPParserConstants.javaTokenManagerError.java

CPPParser.javaParseException.java

How JavaCC worksHow JavaCC works


cpp.jj


parserspecification

actionspecification


Synthesis(JavaCC)




Action specification (I)

• The actions are attached to the syntactic structures

• Based on:• Transformation patterns:

• Function:

• If-then-else structure:

• Modeling guidelines

• Data flow, naming, colors, …

• The actions are attached to the syntactic structures

• Based on:• Transformation patterns:

• Function:

• If-then-else structure:

• Modeling guidelines

• Data flow, naming, colors, …

void sign_init(void){ …}

if ( expression ) { statement1 } else { statement2 }


Action specification (II)

• Block construction is possible through the Matlab script language:

• Implementation of the actions:• Java class hierarchy – Node class subtype• Each class implements the process() method in a specific way, wrapping the

output action; e.g. EqualityExpression:

String process ( PrintWriter outputStream, String prefix ) {String rightHandSide = getChild(0).process(outputStream, prefix); // process the right-hand sideString rightHandSide = getChild(1).process(outputStream, prefix); // process the left-hand sideoutputStream.print(“add_block(built-in/Relational Operator‘“ + ”, ‘” + prefix + ”/eq’, Operator’, ‘==’)”);outputStream.print(“add_line(‘” + prefix + ”’, “ + rightHandSide + ”/1’, ‘eq/1’)”);outputStream.print(“add_line(‘” + prefix + ”’, “ + leftHandSide + ”/1’, ‘eq/2’)”); // interconnect the blocksreturn “eq/1”; // return

the output port}

• Block construction is possible through the Matlab script language:

• Implementation of the actions:• Java class hierarchy – Node class subtype• Each class implements the process() method in a specific way, wrapping the

output action; e.g. EqualityExpression:

String process ( PrintWriter outputStream, String prefix ) {String rightHandSide = getChild(0).process(outputStream, prefix); // process the right-hand sideString rightHandSide = getChild(1).process(outputStream, prefix); // process the left-hand sideoutputStream.print(“add_block(built-in/Relational Operator‘“ + ”, ‘” + prefix + ”/eq’, Operator’, ‘==’)”);outputStream.print(“add_line(‘” + prefix + ”’, “ + rightHandSide + ”/1’, ‘eq/1’)”);outputStream.print(“add_line(‘” + prefix + ”’, “ + leftHandSide + ”/1’, ‘eq/2’)”); // interconnect the blocksreturn “eq/1”; // return

the output port}

add_block(…) { blocks for the logical expression }add_block(‘built-in/Subsystem’, ‘{prefix}/statement1’)add_block(‘built-in/Subsystem’, ‘{prefix}/statement2’)add_block(‘built-in/Logical Operator’, ‘…/not’, ‘Operation’, ‘NOT’)add_line(‘{prefix}’, ‘{logical exprn out}/1’, ‘statement1/Enable’)add_line(‘{prefix}’, ‘{logical exprn out}/1’, ‘not/1’)add_line(‘{prefix}’, ‘not/1’, ‘statement2/Enable’)


cpp.jj


parserspecification

actionspecification


Synthesis(JavaCC)




The translation process

• Builds up• a parse tree from the source code according to the lexical/syntactic definitions

• consists of Node class subtypes • the nodes wrap the appropriate output actions

• symbol tables – attached to Scopes:• type-, variable-, function- and port-table• efficient - using hash map

C2Model.jar – customized parser and code generatorC2Model.jar – customized parser and code generator

Process overviewProcess overview

C2Model.jar(customized parser and code generator)

Source codesign.c

Matlab scriptsign.m

Matlab Simulink modelsign.mdl


The translation process – example

typedef struct { int i, j;} stru;

void fcn1(void) { a = b;}

int fcn2(int u, int v) { if ((a<b) && (c+d <= e)) stru.i = u + v;}

int fcn3(int h) { if (a == b) { u = c + d; } else { v = r + t; }}

Source C file (test.c)Source C file (test.c)

TranslationUnit [4] … ExternalDeclaration [1] FunctionDefinition [3] DeclarationSpecifiers [1] TypeSpecifier [0] Declarator [1] DirectDeclarator [1] token: fcn1 … CompoundStatement [1] StatementList [1] Statement [1] ExpressionStatement [1] Expression [1] AssignmentExpression [3] UnaryExpression [1] PostfixExpression [1] PrimaryExpression [0] token: a AssignmentOperator [0] AssignmentExpression [1] … PrimaryExpression [0] token: b …

Parse treeParse tree

C2Model.jar


The translation process – example (ctd.)

new_system('test')add_block('built-in/Subsystem','test/fcn1')add_block('built-in/Outport','test/fcn1/a')set_param('test/fcn1/a', …)add_block('built-in/Inport','test/fcn1/b')set_param('test/fcn1/b', …)add_line('test/fcn1', 'b/1', 'a/1')…save_system('test')

Matlab script (test.m)Matlab script (test.m)C2Model.jar

Simulink modelSimulink model

Matlab

Parse treeParse tree


Achievements and open questions

• The lexical and syntactic definitions are complete

• The symbol tables for each scope are constructed correctly• Type-, variable-, function- and port-table

• The actions are implemented for:• All binary and n-ary operations• Assignment and conditional expressions• Selection statement, jump statement, iteration statement

• Bus systems are created for structures• Bus selectors are used for operations on structure members

• Operational on the entire sign.c

• Open questions:• Handling of function-calls• Handling of arrays

• The lexical and syntactic definitions are complete

• The symbol tables for each scope are constructed correctly• Type-, variable-, function- and port-table

• The actions are implemented for:• All binary and n-ary operations• Assignment and conditional expressions• Selection statement, jump statement, iteration statement

• Bus systems are created for structures• Bus selectors are used for operations on structure members

• Operational on the entire sign.c

• Open questions:• Handling of function-calls• Handling of arrays


Results – Bus systems


Results – Conditional operations


Results – If-then-else structure


Results – Functions


Conclusion

• A new automated translation method has been explored, based on parsing and a third party compiler generator, which transforms source code written in C/C++ to Matlab/Simulink models.

• This yields fast and error-free operation, and has proven capable of handling large source codes without human intervention.

• Although there are some issues concerning the organization of the output models (localization and positioning), results at this stage are encouraging.

• Switching the implemented actions, the parser can be adapted to any “bit-by-bit transformation”.

• However, the focus of this approach is the pure source code, not the logic and the functionality.

• This is the reason, why it is unable to meet the simplification and the re-engineering issues, which are among the essential objectives of the entire project.

• Therefore the developed tool could only assist the transformation work.

• A new automated translation method has been explored, based on parsing and a third party compiler generator, which transforms source code written in C/C++ to Matlab/Simulink models.

• This yields fast and error-free operation, and has proven capable of handling large source codes without human intervention.

• Although there are some issues concerning the organization of the output models (localization and positioning), results at this stage are encouraging.

• Switching the implemented actions, the parser can be adapted to any “bit-by-bit transformation”.

• However, the focus of this approach is the pure source code, not the logic and the functionality.

• This is the reason, why it is unable to meet the simplification and the re-engineering issues, which are among the essential objectives of the entire project.

• Therefore the developed tool could only assist the transformation work.

transformation of c code to matlab/simulink models approach based on parsing vilmos zsombori...

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