memoizer

Process call memoizer similar to memoize.py but written in C++11 with direct calls to ptrace for maximum performance. Uncached run-time overhead is ca 10 percent.

Inspired by https://github.com/nelhage/ministrace/ and http://blog.nelhage.com/2010/08/write-yourself-an-strace-in-70-lines-of-code/

Usage

memoized <program> <program args>

Enables

• caching,
• detection of process flow: consumer inputs of producer of outputs,
• safe parallelization,
• immutable persistent storage of inputs and outputs,
• detect cyclic dependencies (inputs same as outputs),

Features

• tracks calls to read() (inputs),
• tracks calls to write() and its potential moves via rename() (outputs),
• tracks calls to stat() and access() (inputs),
• intercepts calls to stat() to peek at its modification time (st_mtime) (inputs),

Planned Features

Default

Assert that inputs are not changed during execution.

Optional

Assert that inputs are only project-relative reads from persistent inputs, that is non-modified files (with Git status up-to-date):

• --assert-persistent-relative-reads

Assert read and writes from specific set of directories:

• --only-reads-from=DIRS
• --only-writes-to=DIRS

Environment control:

• --empty-default-env, --no-default-env
• --set-env='PATH=PATH_VALUE:CC=CC_VALUE'
• --use-existing-env-vars=VAR1,VAR2