I am new to Rascal and I am looking forward to construct Control Flow Graph for java. How to make use of DCFlow to construct it?
This is something I've started on but hasn't been completed yet (mainly due to a lack of time, most of my work is on PHP program analysis). Once this is fully defined I'll post it on GitHub. My goal is to build it over the M3 definition of Java since we already have the extraction code in place to generate M3 models, and these optionally include ASTs (which we need for CFG generation).
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Will there be an equivelent of the c# Reflection.Emit namespace in dart?
Reflection.Emit has a number of classes that are used to build types at run time and adding properties, configering their getters and setter and building methods and event handlers all at run time, which is really powerfull when it comes to metaprogramming.
my idea is about generating my data models at run time and caching them in a map so i can create instances at run time and add new methods and properties to them when i need to and not having to use mirrors often after generating the class, this could be really useful when writing ORMs and more dynamic applications where you use reflection once rather than using it every time you need to modify an instance
My questions are:
Will there be such thing in the future versions of dart? they mention
something about a Mirror Builder but i am not sure if does the same
thing, can some one please confirm if thats what a Mirror Builder is
about?
another question is, if i am able to generate my data types on the
server as strings, is there a way to to compile them before sending
them to the client and map them in a Map and use this Map to create instances?
I have seen discussions that this should be supported at some time but as far as I know will not be started to work on in the near future.
Similar requirements are usually solved by code generation at build time (Polymer, Angular, others) by transformers which analyze the code and generated code for reflective property access or code snippets in HTML.
Smoke is a package that aims to simplify this.
Code generation has the advantage that the amount of code needed to be downloaded by the client is much smaller.
When you do code generation at runtime you need a compiler and that is a lot of code that needs to be downloaded into the browser.
try.dartlang.org takes a such an approach. The source is available here https://code.google.com/p/dart/source/browse/branches/bleeding_edge/dart/site/try/ .
It includes dart2js (built to JavaScript) and runs a background isolate that compiles the Dart code to JS.
I'm taking a compiler-design class where we have to implement our own compiler (using flex and bison). I have had experience in parsing (writing EBNF's and recursive-descent parsers), but this is my first time writing a compiler.
The language design is pretty open-ended (the professor has left it up to us). In class, the professor went over generating intermediate code. He said that it is not necessary for us to construct an Abstract Syntax Tree or a parse tree while parsing, and that we can generate the intermediate code as we go.
I found this confusing for two reasons:
What if you are calling a function before it is defined? How can you resolve the branch target? I guess you would have to make it a rule that you have to define functions before you use them, or maybe pre-define them (like C does?)
How would you deal with conditionals? If you have an if-else or even just an if, how can you resolve the branch target for the if when the condition is false (if you're generating code as you go)?
I planned on generating an AST and then walking the tree after I create it, to resolve the addresses of functions and branch targets. Is this correct or am I missing something?
The general solution to both of your issues is to keep a list of addresses that need to be "patched." You generate the code and leave holes for the missing addresses or offsets. At the end of the compilation unit, you go through the list of holes and fill them in.
In FORTH the "list" of patches is kept on the control stack and is unwound as each control structure terminates. See FORTH Dimensions
Anecdote: an early Lisp compiler (I believe it was Lisp) generated a list of machine code instructions in symbolic format with forward references to the list of machine code for each branch of a conditional. Then it generated the binary code walking the list backwards. This way the code location for all forward branches was known when the branch instruction needed to be emitted.
The Crenshaw tutorial is a concrete example of not using an AST of any kind. It builds a working compiler (including conditionals, obviously) with immediate code generation targeting m68k assembly.
You can read through the document in an afternoon, and it is worth it.
I have existing java code and need to create Design Document based on that.
For starter even if I could get all functions with input / output parameters that will help in overall proces.
Note: There is not commeted documentation on any procedures, function or classes.
Last but not least. Let me know for any good tool which will reduce time required for this phase. As currently we write every flow and related stuffs.
What you want is just too much. Quoting Linus Torvalds: “Good code is its own best documentation.”. Anyway, I digress.
You might want to look into UML tools which generate class/sequence diagrams from the code. There are many of them but only a handful support reverse engineering (into and from the class diagram), and even fewer subset support the same to/from sequence diagram. I only know MagicDraw could do this, but I am biased as I used to work for the manufacturer of this tool so do your shopping around first.
Use java docs: http://www.oracle.com/technetwork/java/javase/documentation/index-137868.html
or Introspection: http://docs.oracle.com/javase/tutorial/reflect/class/classMembers.html
I am not asking the static code analysis which is provided by StyleCop or Fxcop. Both are having different purpose and it serves well. I am asking whether is there a way to find the code coverage of your user control or sub module? For ex, you have an application which uses the helper classes in a separate assembly. Inorder to ensure the unit testing code coverage, we need to run the application and ensure using NCover or similar tool.
My requirement is, without running it, is there any possible to find code coverage of the helper classes or similar kind of assemblies?
See Static Estimation for Test Coverage for a technique that estimates coverage without executing the source code.
The basic idea is to compute a program slice for each test case, and then "count" what the slice enumerates. A (forward) slice is effectively that part of a program that you can reach from a specific starting point in the code, in this case, the test code.
While the technical paper above is hard to get if you're not an ACM member [or you didn't attend the conference where it was presented :], there's a slide presentation here.
Of course, running this static estimator only tells you (roughly) what code will be exercised. It doesn't substitute for actually running the tests, and verifying that they pass!
In general, the answer is no. This is equivalent to the halting problem, which is not computable.
There are (research) tools based on abstract interpretation or model checking that can show coverage properties without execution, for subsets of language. See, e.g.
"Analyzing Functional Coverage in Bounded Model Checking", Grosse, D. Kuhne, U. Drechsler, R. 2008
In general, yes, there are approaches, but they're specialized, and may require some formal methods experience. This kind of stuff is still cutting edge research.
I would say no; with the exception of 'dead code' which a compiler can determine.
My definition of code coverage is a result which indicates how many times each line of code is run in your program: which, of course, means running the program. The determining factor here is usually the values of data passing through the program which the determine the paths of executions taken by conditionals. A static analysis, like a compiler, could deduce lines of code that cannot run under any conditions.
An example here is if your program uses a third-party library, but there is a bug in the library. If your program never uses those parts of the library, or the data you send to the library causes it to avoid the bug, then you won't be affected.
You could write a program that, by reflection, assumes that all conditionals will be taken, and follows all function calls, through all derived classes, but I'm not sure what this will tell you. It certainly can't tell you whether or not there are any bugs in the lines of code covered.
Coverity Static Analysis is a tool that is can identify many secuirty flaws in a program. It can also identify dead code and can be used to help satisfy testing regulations such as D0178B which requires that the developers demonstrate that all code can be executed.
If you are using Visual Studio, you can first run 'Analyze Code Coverage', Then you can export code Coverage results using below Button(marked in Green) in Visual Studio:
Later you can import the Coverage Result file back to Visual Studio
Out of curiosity, I wonder what can people do with parsers, how they are applied, and what do people usually create with it?
I know it's widely used in programming language industry, however I think this is just a tiny portion of it, right?
Besides special-purpose languages, my most ambitious use of a parser generator yet (with good old yacc back in C, and again later with pyparsing in Python) was to extract, validate and possibly alter certain meta-info from SQL queries -- parsing SQL properly is a real challenge (especially if you hope to support more than one dialect!-), a parser generator (and a lexer it sits on top of) at least remove THAT part of the job!-)
They are used to parse text....
To give a more concrete example, where I work we use lexx/yacc to parse strings coming over sockets.
Also from the name it should give you an idea what javacc is used for (java compiler compiler!)
Generally to parse Domain Specific Languages or scripting languages, or similar support for code snipits.
Previously I have seen it used to parse the command line based output of another software tool. This way the outer tool (VPN software) could re-use the base router IPSec code without modification. As lots of what was being parsed was IP Route tables and other structured repeated text.
Using a parser allowed simple changes when the formatting changed, instead of trying to find and tweak the a hand written parser. And the output did change a few times of the life of the product.
I used parsers to help process +/- 800 Clipper source files into similar PRGs that could be compiled with Alaksa Xbase 32.
You can use it to extend your favorite language by getting its language definition from their repository and then adding what you've always wanted to have. You can pass the regular syntax to your application and handle the extension in your own program.