I implemented a random number generator in vdm++. But I wanted to the seed to be the clock time from the computer. Does anyone know if there is a equivalent vdm++ function to c++ function time(NULL)?
Thank you.
There doesn't exist any build-in lib to get the system time like time(NULL) but it is easy to create such a function in Java and link it to your model if you are using the Overture IDE for VDM.
The Overture User Guide has a section about this: 14.1 Defining Your Own Java Libraries to be used from Overture.
You have to create a jar file with a java class that gives you the system time like this:
public class SystemTime
{
public static Value time()
{
return new RealValue(System.currentTimeMillis());
}
}
And its VDM counterpart:
class SystemTime
operations
public static time : () ==> real
time() == is not yet specified;
end SystemTime
Then place the jar and vdm file inside the project like this:
Project root/
lib/
systemtime.jar
systemtime.vdmpp
Now you can use the VDM operation SystemTime`time() to get the system time.
Related
I would like to create a vscode extension which can help with unit testing and "live" debugging.
Lets say you have the following code:
/*1*/ export class Test {
/*2*/ public add(a: any, b: any): any {
/*3*/ return a + b;
/*4*/ }
/*5*/ }
Live debugging:
New option in the context menu to test the add function (e.g. something similar to current Peek Definition) where you can provide the function input and check the output in a new smaller editor.
Unit test generation:
After you wrote an input and checked the output you can simply generate a new unit test from it.
Now I'm only at the beginning of this project but it seems like getting type information is much more complicated than I expected.
First I would like to get some simple type information (based on cursor position) e.g.:
Line 1 is a class
Line 2-4 is a function
Line 5 is a class
After hours of Google search I think what I have to do is to implement my own TypeScript Language Service Plugin and use it somehow in my extension.
My questions:
Is there any extension similar to my idea which I could use?
Is there an easier way to get the type information I need?
Am I on a right track at all?
Do you have some material about how to use this language service plugin from extension?
P.S. I know that it won't be easy (e.g. several states with different visibility), but good practice for a home project.
Is it possible to run the simulation for a certain amount of ticks, and then read the value of selected statistics from the Python config script?
Edit: a patch has been submitted at: https://gem5-review.googlesource.com/c/public/gem5/+/33176
As of 3ca404da175a66e0b958165ad75eb5f54cb5e772 it does not seem possible, but it is likely easy to implement.
We already have a loop that goes over all stats in the Python under src/python/m5/stats/__init__.py, so there are python stat objects fully exposed and iterated, but the actual stat value appears not exposed to them, only the stat name:
def _dump_to_visitor(visitor, root=None):
# Legacy stats
if root is None:
for stat in stats_list:
stat.visit(visitor)
# New stats
def dump_group(group):
for stat in group.getStats():
stat.visit(visitor)
The visit method then leads the value to be written out to the stat file, but the Python does not do it.
However, visit is already a pybind11 Python C++ extension defined at src/python/pybind11/stats.cc:
py::class_<Stats::Info, std::unique_ptr<Stats::Info, py::nodelete>>(
m, "Info")
.def("visit", &Stats::Info::visit)
;
so you would likely need to expose the value there.
One annoyance is that each stat type that derives from Stats::Info has a different data representation, e.g. scalars return a double:
class ScalarInfo : public Info
{
public:
virtual Counter value() const = 0;
but vectors an std::vector:
class VectorInfo : public Info
{
public:
virtual const VCounter &value() const = 0;
and so there is no base value() method due to the different return types, you'd juts need to expose one per base class.
TODO I couldn't see the value() method on the Python still, likely because they were still objects of the base class, needs more investigating.
You can use variation of the gem5-stat-summarizer. gem5-stat-summarizer is used to extract selected gem5 statistics to a csv file when you have multiple stats.txt files
I've been using one global variable called system which is defined in index.ts.
When I was using internal modules that went fine, probably because I started compiling in index.ts with --out.
Now I'm switching to external modules the compiler throws errors for the global variable 'system'.
I kept a single in each file with some .d.ts files for external libs, and I tried adding
declare var system:System
in that shared reference file, but that didnt work.
What does work is adding the declare statement to each file that uses the global variable.
So my question is if this is the way I should do it (declaring in every file), or if there's something I'm missing.
Tnx!
In Visual Studio 2013 (Update 3) the mere presence of system.d.ts is enough in the test I set up...
system.d.ts (I made this up)
interface System {
someStuff(): void;
}
declare var system: System;
afile.ts
class Lower {
constructor(private word: string) {
system.someStuff();
}
}
export = Lower
And I could access system.someStuff(); from anywhere.
If you are using a different IDE, you may need to add:
///<reference path="system.d.ts" />
This hints to the compiler that the definition exists, but doesn't actually import system as an external module (you can use import system = require('system'); if you want to load it like a module, but I don't think that's what you want in this case as you've stated that this is a global variable.
i've assumed that dumping a .bc file from a module was a trivial operation, but now,
first time i have to actually do it from code, for the life of me i
can't find one missing step in the process:
static void WriteModule ( const Module * M, BitstreamWriter & Stream )
http://llvm.org/docs/doxygen/html/BitcodeWriter_8cpp.html#a828cec7a8fed9d232556420efef7ae89
to write that module, first i need a BistreamWriter
BitstreamWriter::BitstreamWriter (SmallVectorImpl< char > &O)
http://llvm.org/docs/doxygen/html/classllvm_1_1BitstreamWriter.html
and for a BitstreamWriter i need a SmallVectorImpl. But, what next?
Should i write the content of the SmallVectorImpl byte by byte on a
file handler myself? is there a llvm api for this? do i need something
else?
The WriteModule function is static within lib/Bitcode/Writer/BitcodeWriter.cpp, which means it's not there for outside consumption (you can't even access it).
The same file has another function, however, called WriteBitcodeToFile, with this interface:
/// WriteBitcodeToFile - Write the specified module to the specified output
/// stream.
void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out);
I can't imagine a more convenient interface. The header file declaring it is ./include/llvm/Bitcode/ReaderWriter.h, by the way.
I use following code :
std::error_code EC;
llvm::raw_fd_ostream OS("module", EC, llvm::sys::fs::F_None);
WriteBitcodeToFile(pBiFModule, OS);
OS.flush();
and then disassemble using llvm-dis.
There is a "NameAndType" structure in the constants pool in .class file.
It is used for dynamic binding.
All methods that class can "export" described as "signature + return type".
Like
"getVector()Ljava/util/Vector;"
That breakes my code when return type of the method in some .jar is changed, even if new type is narrower.
i.e:
I have the following code:
List l = some.getList();
External .jar contains:
public List getList()
Than external jar changes method signature to
public ArrayList getList().
And my code dies in run-time with NoSuchMethodException, because it can't find
getList()Ljava/util/List;
So, I have to recompile my code.
I do not have to change it. Just recompile absolutely the same code!
That also gives ability to have two methods with one signature, but different return types! Compiler would not accept it, but it is possible to do it via direct opcoding.
My questions is why?
Why they did it?
I have only one idea: to prevent sophisticated type checking in the runtime.
You need to look up to the hierarchy and check if there is a parent with List interface.
It takes time, and only compiler has it. JVM does not.
Am I right?
thanks.
One reason may be because method overloading (as opposed to overriding) is determined at compile time. Consider the following methods:
public void doSomething(List util) {}
public void doSomething(ArrayList util) {}
And consider code:
doSomething(getList());
If Java allowed the return type to change and did not throw an exception, the method called would still be doSomething(List) until you recompiled - then it would be doSomething(ArrayList). Which would mean that working code would change behavior just for having recompiled it.