When using CSScript.Evaluator.Reset(), will this reset anyone else that is currently using the same script or build?
Another way of asking my question.
script = CSScript.Evaluator.LoadCode(scriptString);
If another user came thru and called the same code, but an error occurred.
Would the original compile still be good and safe?
Also CSScript.Evaluator.AutoResetEvaluatorOnError = true, this does not seem to be working.
After i cause an error in the code, then fix it. The compile will not work til i reset my app, or use Reset().
Using Reset is working, But that's the reason for my initial question.
I am using CSScript.Evaluator.LoadCode and looking at CSScript.Evaluator.LoadMethod, but getting the same issues.
These are not huge scripts, but may run in large batches or loops.
Not against unique naming, cause i will have build for every run anyway.
But i'm not sure the cache is working either.
Where is the location of the cache folder, when CSScript.CacheEnabled is enabled?
Would the original compile still be good and safe?
Yes it would as when you hold the reference to the compiled object it is YOURS. I is good even if you destroy the compiler.
Also CSScript.Evaluator.AutoResetEvaluatorOnError = true, this does not seem to be working.
This setting triggers so cold SoftReset, which is different to the Reset only by re-referencing the assemblies and re-creating the CompilerSettings object. It the time of the initial implementation SoftReset was sufficient to fully clear Mono.Evaluator. I will need to check may be it is not the case any more. I will let you know the outcome.
Where is the location of the cache folder, when CSScript.CacheEnabled is enabled?
The caching doesn't cover Mono Evaluator as the all assemblies are in the memory and cannot be cached.
Everything that is accessed through CSScript.Evaluator.* applicable to the Mono compiler and everything that it accessed through CSScript.* is a CodeDOM compiler, which indeed implements caching mechanism.
Related
Take the hello-world as an example.
I have couple of questions:
What does v8::Isolate do? Does it create an new thread
What does v8::Isolate::Scope do?
What does v8::HandleScope do?
What does v8::Local<v8::Context> do?
What does v8::Script::Compile do? Does it compile the js code directly to machine code?
Thanks your for your help!
See the official wiki:
An isolate is a VM instance with its own heap.
A local handle is a pointer to an object. All V8 objects are accessed using handles, they are necessary because of the way the V8 garbage collector works.
A handle scope can be thought of as a container for any number of handles. When you've finished with your handles, instead of deleting each one individually you can simply delete their scope.
A context is an execution environment that allows separate, unrelated, JavaScript code to run in a single instance of V8. You must explicitly specify the context in which you want any JavaScript code to be run.
These concepts are discussed in greater detail in the Embedder's Guide.
Once you've read the existing documentation, if anything is still unclear, please ask more specific questions.
Regarding (5): In current versions of V8, v8::Script::Compile compiles bytecode for V8's interpreter. In earlier versions, it compiled unoptimized machine code. The difference is an internal implementation detail that you don't need to worry about :-)
I am learning compilers and want to make changes of my own to GCC parser and lexer. Is there any testing tool or some another way available which let me change gcc code and test it accordingly.
I tried changing the lexical analysis file but now I am stuck because I don't know how to compile these files. I tried the compilation using other GCC compiler but show errors. I even tried configure and make but doing this with every change does not seems efficient.
The purpose of these changes is just learning and I have to consider GCC only as this is the only compiler my instructor allowed.
I even tried configure and make but doing that wit every change is not at all efficient.
That is exactly what you should be doing. (Well, you don't need to re-configure after every change, just run make again.) However, by default GCC configures itself in bootstrap mode, which means not only does your host compiler compile GCC, that compiled GCC then compiles GCC again (and again). That is overkill for your purposes, and you can prevent that from happening by adding --disable-bootstrap to the configuration options.
Another option that can help significantly reduce build times is enabling only the languages you're interested in. Since you're experimenting, you'll likely be very happy if you create something that works for C or for C++, even if for some obscure reason Java happens to break. Testing other languages becomes relevant when you make your changes available for a larger audience, but that isn't the case just yet. The configuration option that covers this is --enable-languages=c,c++.
Most of the configuration options are documented on the Installing GCC: Configuration page. Throroughly testing your changes is documented on the Contributing to GCC page, but that's likely something for later: you should know how to make your own simpler tests pass, by simply trying code that makes use of your new feature.
You make changes (which are made "permanent" by saving the files you modify), compile the code, and run the test suite.
You typically write additional tests or remove those that are invalidated by your changes and that's it.
If your changes don't contribute anything "positive" to the compiler upstream will probably never accept them, and the only "permanence" you can get is the modifications in your local copy.
I am trying to debug an intermittent parallel build issue in my cmake build system around some generated files. It is however difficult to reliably test or reproduce the issue.
Does anyone know any way to exacerbate or sensitise such issues? Or other strategies for debugging them?
It is likely a missing add_dependencies to force one target to build completely before another begins, or an add_custom_command output that is used in more than one library.
If both libraries start building at the same time, and they both trigger running the custom command at the same time, then you'll get two competing custom commands running, and they may overwrite each other's results, or intermingle results.
Is your code public? Can you post it for others to inspect?
One good strategy is simply exposing it to other developers for "more eyes"...
I was wondering if there is a quick and effective way to remove all the unused variables (local, instance, even properties) in xcode... I am doing a code cleanup on my app and if I knew a quick way for code refactoring it would help me a lot...
Thanks...
It's being a long time since you made your question and maybe you found an answer already, but from an answer to a related question:
For static analysis, I strongly
recommend the Clang Static Analyzer
(which is happily built into Xcode 3.2
on Snow Leopard). Among all its other
virtues, this tool can trace code
paths an identify chunks of code that
cannot possibly be executed, and
should either be removed or the
surrounding code should be fixed so
that it can be called.
For dynamic analysis, I use gcov (with
unit testing) to identify which code
is actually executed. Coverage reports
(read with something like CoverStory)
reveal un-executed code, which —
coupled with manual examination and
testing — can help identify code that
may be dead. You do have to tweak some
setting and run gcov manually on your
binaries. I used this blog post to get
started.
Both methodologies are exactly for what you want, detecting unused code (both variables and methods) and removing them.
I have a workspace for running an H.263 Video Encoder in a loop for 31 times i.e. the main is executed 31 times to generate 31 different encoded bit streams. This MS Visual Studio 2005 Workspace has all C source files. When i create a "DEBUG" configuration for the workspace and build and execute it, it runs fine, i.e. it generates all the 31 output files as expected.
But when I set the configuration of the workspace to "RELEASE" mdoe, and repeat the process, the encoder crashes at some test case run.
Now to debug this is verified following:
Analyzed the code to see if there was any variable initialization being missed out in every run of the encoder
Checked the various Workspace(Solution) options in both the modes (DEBUG and RELEASE).
There are some obvious differences, but i turned the optimization related options explicitly same in both modes.
But still could not nail the problem and find a fix for that. Any pointers?
-Ajit.
It's hard to say what the problem might be without carefully inspecting the code. However...
One of the differences between debug and release builds is how the function call stack frame is set up. There are certain classes of bad things you can do (like calling a function with the wrong number of arguments) that are not fatal in a debug build but crash horribly in a release build. Perhaps you could try changing the stack frame related options (I forget what they're called, sorry) in the release build to the same as the debug build and see whether that helps.
Another thing might be to enable all the warnings you possibly can, and fix them all.
Could be a concurrency problem of two threads. The DEBUG configuration slows the execution down, so the problem does not occur. But, only a guess.
Interesting problem.. Are you sure you have no conditional compilation code lurking around that is not being compiled in release mode? i.e:
#if (DEBUG)
// Debug Code here
#else
// Release Code here
#endif
Thats the only thing I can really think of.. Never experienced anything like this myself..
Can you add the debug symbols to the release build and run it in the debugger to see where and why it crashed?
Yeah, those bastard crashes are the hardest to fix. Fortunatly, there are some steps you can do that will give you clues before you resort to manually looking at the code and hope to find the needle.
When does it crash? At every test? At a specific test? What does that test does that the others don't?
What's the error? If it's an access violation, is there a pattern to where it happens? If the addresses are low, it might mean there is an uninitialised pointer somewhere.
Is the program crashing with Debug configuration but without the debugger attached? If so, it's most likely a thread synchronisation problem as John Smithers pointed out.
Have you tried running the code through an analyser such as Purify? It's slow but it's usually worth the wait.
Try to debug the release configuration anyway. It will only dump assemblies but it can still give you an indication of what happens such as if the code pointer jumps in the middle of garbage or hits a breakpoint in an external library.
Are you on an Intel architecture? If not, watch for memory alignement errors, they hard crash without warning on some architectures and those codec algorithm tend to create those situations a lot since they are overly optimized.
Are you sure there are no precompile directives that, say, ignores some really important code in Release mode but allows them in Debug?
Also, have you implemented any logging that might point out to the precise assembly that's throwing the error?
I would look at the crash in more detail - if it's crashing in a test case, then it sounds pretty easily reproducible, which is usually most of the challenge.
Another thing to consider: in debug mode, the variables are initialized with 0xCCCCCCCC instead of zero. That might have some nasty side effects.