GC for Stella

Build instructions

Simplest example

1. Configure CMake: cmake -B build
2. Build with CMake: cmake --build build

This will generate build/libstella_gc.a for the GC (without runtime) and build/libstella_runtime.a for the Stella runtime library.

You can use the GC object file independently -- just link it with your own runtime and have fun!

Build with Stella programs

-DBUILD_STELLA_PROGRAMS=ON -DSTELLA_COMPILER=/path/to/stella/compiler

If you add these two arguments to the "Configure CMake" command, CMake will also build Stella programs from the examples/ directory. It will statically link them with the runtime and GC. Built binaries will be located under build/stella_examples.

For each Stella program, two binaries will be generated. For instance, for the program exp.st files exp and exp__epsilon_gc will be generated. The former is linked with the actual GC implementation, the latter -- with epsilon GC that does nothing.

Additional development options

GC parameters:

• -DMAX_ALLOC_SIZE=1024 Defines the size of available memory (in bytes)

Stella options:

• -DSTELLA_DEBUG=ON|OFF Defines the STELLA_DEBUG macro
• -DSTELLA_GC_STATS=ON|OFF Defines the STELLA_GC_STATS macro
• -DSTELLA_RUNTIME_STATS=ON|OFF Defines the STELLA_RUNTIME_STATS macro

Statis checks for GC:

• -DSTRICT_BUILD_MODE=ON|OFF Build the GC source files with -Wall -Wpedantic ...

Runtime checks for GC:

• -DSTELLA_GC_DEBUG_MODE=ON|OFF Enable logging for GC
• -DSTELLA_GC_MOVE_ALWAYS=ON|OFF This options tells GC to marking-and-moving phase every time an object is allocated is called
• -DBUILD_WITH_SANITIZERS=ON|OFF Build everything with address sanitizers

GC Statistics Example

$ echo 5 | ./build/stella_examples/bin/factorial_functional

...

------------------------------------------------------------
Garbage collector (GC) statistics:
MAX_ALLOC_SIZE:                  10,000 bytes
Total memory allocation:         14,368 bytes (888 objects)
Maximum residency:               4,056 bytes
Total number of GC cycles:       888 times
Maximum number of roots:         41