beremiz / matiec

MATIEC - IEC 61131-3 compiler The following compiler has been based on the FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10) Copyright (C) 2003-2012 Mario de Sousa (msousa@fe.up.pt) **************************************************************** **************************************************************** **************************************************************** ********* ********* ********* ********* ********* O V E R A L L G O A L S ********* ********* ********* ********* ********* **************************************************************** **************************************************************** **************************************************************** This project has the goal of producing an open source compiler for the programming languages defined in the IEC 61131-3 standard. These programming languages are mostly used in the industrial automation domain, to program PLCs (Programmable Logic Controllers). This standard defines 5 programming languages: • IL : Instructtion List A textual programming language, somewhat similar to assembly. • ST : Structured Text A textual programming language, somewhat similar to Pascal. • FBD: Function Block Diagram A graphical programming language, somewhat similar to an electrical circuit diagram based on small scale integration ICs (Integrated Circuits) (counters, AND/OR/XOR/... logic gates, timers, ...). • LD : Ladder Diagram A graphical programming language, somewhat similar to an electrical circuit diagram based on relays (used for basic cabled logic controllers). • SFC: Sequential Function Chart A graphical programming language, that defines a state machine, based largely on Grafcet. (may also be expressed in textual format). Of the above 5 languages, the standard defines textual representations for IL, ST and SFC. It is these 3 languages that we target, and we currently support all three, as long as they are expressed in the textual format as defined in the standard. Currently the matiec project generates two compilers (more correctly, code translaters, but we like to call them compilers :-O ): iec2c, and iec2iec Both compilers accept the same input: a text file with ST, IL and/or SFC code. The iec2c compiler generates ANSI C code which is equivalent to the IEC 61131-3 code expressed in the input file. The iec2iec compiler generates IEC61131-3 code which is equivalent to the IEC 61131-3 code expressed in the input file. This last compiler should generate and output file which should be almost identical to the input file (some formating may change, as well as the case of letters, etc.). This 'compiler' is mostly used by the matiec project contributors to help debug the lexical and syntax portions of the compilers. To compile/build these compilers, just $./configure; make **************************************************************** **************************************************************** **************************************************************** ********* ********* ********* ********* ********* O V E R A L L A R C H I T E C T U R E ********* ********* ********* ********* ********* **************************************************************** **************************************************************** **************************************************************** The compiler works in 4(+1) stages: ================================== Stage 1 - Lexical analyser - implemented with flex (stage1_2/iec_flex.ll) Stage 2 - Syntax parser - implemented with bison (stage1_2/iec_bison.yy) Stage pre3 - Populate symbol tables - Symbol tables that will ease searching for symbols in the abstract symbol tree. Stage 3 - Semantics analyser - currently does type checking only Stage 4 - Code generator - generates ANSI C code Stage 5 - Binary code generator - gcc, javac, etc... (Not integrated into matiec compiler. Must be called explicitly by the user.) Data structures passed between stages, in global variables: ========================================================== 1->2 : tokens (int), and token values (char *) (defined in stage1_2/stage1_2_priv.hh) 2->1 : symbol tables (implemented in util/symtable.[hh|cc], and defined in stage1_2/stage1_2_priv.hh) 2->3 : abstract syntax tree (tree of C++ objects, whose classes are defined in absyntax/absyntax.hh) pre3->3,4 : global symbol tables (defined in util/[d]symtable.[hh|cc] and declared in absyntax_utils/absyntax_utils.hh) 3->4 : abstract syntax tree (same as 2->3), but now annotated (i.e. some extra data inserted into the absyntax tree) 4->5 : file with program in c, java, etc... The compiler works in several passes: ==================================== Stage 1 and Stage 2 ------------------- Executed in one single pass. This pass will: • Do lexical analysis • Do syntax analysis • Execute the absyntax_utils/add_en_eno_param_decl_c visitor class This class will add the EN and ENO parameter declarations to all functions that do not have them already explicitly declared by the user. This will let us handle these parameters in the remaining compiler just as if they were standard input/output parameters. Stage Pre3 ---------- Executed in one single pass. This pass will populate the following symbol tables: • function_symtable; /* A symbol table with all globally declared functions POUs. */ • function_block_type_symtable; /* A symbol table with all globally declared functions block POUs. */ • program_type_symtable; /* A symbol table with all globally declared program POUs. */ • type_symtable; /* A symbol table with all user declared (non elementary) datat type definitions. */ • enumerated_value_symtable; /* A symbol table with all identifiers (values) declared for enumerated types. */ Stage 3 ------- Executes two algorithms (flow control analysis, and data type analysis) in several passes. Flow control: Pass 1: Does flow control analysis (for now only of IL code) Implemented in -> stage3/flow_control…