"compiler_rt" Runtime Library

The compiler_rt project is a simple library that provides an implementation of the low-level target-specific hooks required by code generation and other runtime components. For example, when compiling for a 32-bit target, converting a double to a 64-bit unsigned integer is compiling into a runtime call to the "__fixunsdfdi" function. The compiler_rt library provides optimized implementations of this and other low-level routines.

Goals

Different targets require different routines. The compiler_rt project aims to implement these routines in both target-independent C form as well as providing heavily optimized assembly versions of the routines in some cases. It should be very easy to bring compiler_rt to support a new target by adding the new routines needed by that target.

Where it make sense, the compiler_rt project aims to implement interfaces that are drop-in compatible with the libgcc interfaces.

Features

The current feature set of compiler_rt is:

• Full support for the libgcc interfaces required by these targets:
  • Darwin i386
  • Darwin X86-64
  • Darwin PowerPC
  • Darwin PowerPC 64
• High performance hand tuned implementations of commonly used functions like __floatundidf in assembly that are dramatically faster than the libgcc implementations.
• A target-independent implementation of the Apple "Blocks" runtime interfaces.

Get it and get involved!

TODO.