Typegrind

Typegrind is a type preserving heap profiler for C++ - it collects memory allocation information with type information.

Components

Typegrind consists of two main components:

• Instrumentator, which is a source-to-source compiler, decorating the C++ source with code required for the logger.
• Loggers, which do something useful with the information provided by the instrumented code (e.g. write it to a logfile).

Both components can be used separatedly: the instrumentator with a custom logger, or the loggers with manually or otherwise decorated code. This is accomplished with a simple API between them, consisting of a few macros. For details, see doc/logging_api.md.

Building

Typegrind can be build as a part of the clang build process, for details see doc/building.md

Usage

Typegrind is a Clang Tool, and uses the same parameters as other, builtin tools like clang-check or clang itself.

For details, see doc/usage.md.

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Example

The original source code:

#include <typegrind/log_to_cout.hpp>
#include <iostream>

int main() {
  int* a = new int(3);
  std::cout << *a << std::endl;
  delete a;
  return 0;
}

Is transformed to:

#include <typegrind/log_to_cout.hpp>
#include <iostream>

int main() {
  int* a = TYPEGRIND_LOG_ALLOC("int*", "example.cpp:6", new int(3), sizeof(int));
  std::cout << *a << std::endl;
  TYPEGRIND_LOG_DEALLOC(a, "example.cpp:8", delete a);
  return 0;
}

Which contains two macros defined in typegrind/log_to_cout.hpp, and expands to:

#include <typegrind/log_to_cout.hpp>
#include <iostream>

int main() {
  int* a = typegrind::log_cout::alloc("int*", "example.cpp:6", (new int(3)), sizeof(int));
  std::cout << *a << std::endl;
  typegrind::log_cout::dealloc(a, "example.cpp:8"); (delete a);
  return 0;
}

Known limitations

• Exotic macros related to object allocation will cause compilation errors. For example:

    #define DECL_AN_INT(name) int* name = new int(0);

• Delete loggers might call the pointer expression twice - once for logging, once for deleting it. It has to be extracted into a variable before use.
• Include directives / linker settings aren't modified by typegrind. The projects using it should include the desired logger, and link to it's library if it has one.
• Instrumenting system includes is problematic - an overlay should be used for files outside the project scope

Future work

• Solve the above limitations
• Implement the planned macros in the API (see API docs for details - some of them require more research)
• Improve the usage process (call clang with an in-memory VFS automatically)
• Create production ready standard loggers
• Create a user friendly logger frontend
• Make it possible to build Typegrind without building clang from sources first

Documentation

The documentation can be found under the doc folder in the source, written in markdown, browsable on GitHub.

Credits

Typegrind is based on:

• J. Mihalicza, Z. Porkoláb, and A. Gábor, Type-preserving heap profiler for C++ (2011)
• J. Mihalicza, Analysis and Methods for Supporting Generative Metaprogramming in Large Scale C++ Projects (2014)
• The type-preserving heap-profiler used by NNG Llc., also based on the above articles

License

Typekit is published under the MIT License