Section: Software and Platforms

Low-Level Exchange Format (TireX) and Minimalist Intermediate Representation (MinIR)

Participants : Christophe Guillon [STMicroelectronics] , Fabrice Rastello, Benoît Dupont de Dinechin [Kalray] .

Most compilers define their own intermediate representation (IR) to be able to work on a program. Sometimes, they even use a different representation for each representation level, from source code parsing to the final object code generation. MinIR (Minimalist Intermediate Representation) is a new intermediate representation, designed to ease the interconnection of compilers, static analyzers, code generators, and other tools. In addition to the specification of MinIR, generic core tools have been developed to offer a basic toolkit and to help the connection of client tools. MinIR generators exist for several compilers, and different analyzers are developed as a testbed to rapidly prototype different static analyses over SSA code. This new common format enables the comparison of the code generator of several production compilers, and simplifies the connection of external tools to existing compilers.

MinIR has been extended into TireX, a Textual Intermediate Representation for EXchanging target-level information between compiler optimizers and whole or parts of code generators (a.k.a., compiler back-end). The first motivation for this intermediate representation is to factor target-specific compiler optimizations into a single component, in case several compilers need to be maintained for a particular target (e.g., operating system compiler and application code compiler). Another motivation is to reduce the run-time cost of JIT compilation and of mixed mode execution, since the program to compile is already in a representation lowered to the level of the target processor. Beside the lowering at the target level, the extensions of MinIR include the program data stream and loop scoped information. TireX is currently produced by the Open64/Path64 and the LLVM compilers, with a GCC producer under work. It is used by the LAO code generator.

Detailed information, generic core tools, and LLVM IR based generator for MinIR are available at http://www.assembla.com/spaces/minir-dev/wiki . MinIR was presented at WIR'11  [29] .