Elves, Orcs, and the Memory Growth

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1

Hi folks,

I have an issue with constant memory growth on Linux.
Here is what I do (real code is here[1]):

for (auto &module : modules) {
  auto owningObject = orcCompiler.compileModule(module);
  processObjectFile(owningObject.getBinary());
}

After each compilation of a module memory grows by N megabytes, which is fine and expected.
The problem that the owningObject does not escape the scope, and I expect memory to be freed after each loop iteration.
It works as expected on macOS: memory spikes when we enter the loop body but gets back after we leave the body.
However, on Linux, it grows constantly and eventually exceeds all capacities.

The questions are: what can I do about it? What could hold the memory allocated for each object file? Why is it different between macOS and Linux? Who is the guilty here: the Elf or the Orc?

For your info: I use Orc APIs from LLVM 3.9.
Please let me know if I can provide more relevant information.

I would appreciate any hints and ideas on how to nail the problem down.

[1] https://github.com/mull-project/mull/blob/disable_inmemory_cache/lib/Driver.cpp#L231

Cheers,
Alex.

2

(+Lang, Orcmaster)

Any chance you could provide reproduction steps? (“download this code, run this build command, run this test command”, etc?) Preferably with a smaller/isolated example, but that’s not strictly needed, so long as there’s not lots of external dependencies to worry about, etc.

  • Dave