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agentprog

Can't load bytecode with string literals

12 posts in this topic

Hello!

 

If I compile a script containing string literal to bytecode, it compiles successfully. But when I try to load this bytecode in the application, it says for instance: "LoadByteCode failed. The bytecode is invalid. Number of bytes read from stream: 110". I'm using ScriptStdString implementation and the problem persists both in 2.28.2 and trunk (rev. 1933). Using string class itself and other add-on classes seems fine.

 

Test code (compiles and loads):
[source]int main() {

  return 0;
}[/source]

 

Test code (compiles, but doesn't load):
[source]int main() {

  "abc";
  return 0;

}[/source]

 

UPD: if it matters, my system is x86 Linux, compiler: gcc (GCC) 4.9.0 20140507 (prerelease).

 

UPD2: windows 8 x64 with VS2013 shows the very same results.

Edited by agentprog
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I have test cases with saving and loading bytecode containing string literals. It's odd that I'm not seeing this problem.

 

Still, I'll investigate this further when I get home.

 

Regards,

Andreas

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A typical workflow I use to reproduce this behaviour:

Dump configuration with modifier asrun program. Compile sample code with this configuration into bytecode with separate compiler (modified asbuild), then try to run the compiled bytecode with asrun, which generated the configuration. Anything, containing string literals makes it fail to load the bytecode:

 

[source]

string s1 = "123";

string s2("abc");

s1 = "qwe";

writeln("Hello");

dictionary dict = {{"test", 42}};

[/source]

 

Modifications of asbuild are not very significant (hardcode array's template callback to allow its registration). In asrun i've removed building module from source with CScriptBuilder and added loading from bytecode like this:

[source]

BytecodeStream stream; // file stream with implemented Read()
r = stream.Open(options_.bytecodeFile().c_str());
 
asIScriptModule *mod = engine_->GetModule("Run", asGM_ALWAYS_CREATE);
 
r = mod->LoadByteCode(&stream);  // <- here it fails
 
asIScriptFunction *func = mod->GetFunctionByDecl("int main()");
if (!func) {
  func = mod->GetFunctionByDecl("void main()");
}
 
asIScriptContext *ctx = engine_->CreateContext();
 
r = mod->ResetGlobalVars(ctx);
 
ctx->Prepare(func);
r = ctx->Execute();
ctx->Release();

[/source]

 

Error checks are removed for brevity. Maybe I'm doing something wrong or forgot something?

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I don't think you're doing anything wrong. Or the code wouldn't work even without the string literals in the script.

 

However, from your description I suspect the bug may actually be in the WriteConfigToFile() function, or when the asbuild code parses this configuration to register the engine.

 

Can you send me the config file that you have?

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This file was generated with my version of asrun. Compilation was done fine, so i didn't think the problem could be in it.

 

Config parsing in asbuild is the same as in original asbuild sample, just with some workaround for template callbacks.

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From what I see in writing/reading configuration file, engine properties and string factory are dumped and restored correctly and I don't see anything, that can affect bytecode generation. Both asbuild and asrun are linked against the same AngelScript library, so there should be no problem with version incompatibility.

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I haven't had the time to investigate this yet. Hopefully I'll find the time for it tonight or tomorrow.

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After some experiments, I've found out, that without using string pool everything works fine. When using string pool, for some reason it outputs non-pool version of string factory to configuration. So compiler supposes that string factory returns string and runner expects from it to return const string &.

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I had just managed to set up a test case that reproduced the problem but I hadn't had the time to identify the cause yet. Thanks for saving me the time. :)

 

I'll have it fixed immediately.

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Thank you very much for resolving this problem. Though compiling with gcc you should also add additional #include <stdlib.h> in scripthelper.cpp to compile it :)

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