The C/C++ compilation stack (Intermediate Representations (IR), compilation passes and backends) is encumbered by a steep learning curve, which we believe can be lowered by complementing it with approaches such as source-to-source compilation. Source-to-source compilation is a technology that is widely used and quite mature in certain programming environments, such as JavaScript, but that faces a low adoption rate in others. In the particular case of C and C++ some of the identified factors include the high complexity of the languages, increased difficulty in building and maintaining C/C++ parsers, or limitations on using source code as an intermediate representation. Additionally, new technologies such as Multi-Level Intermediate Representation (MLIR) have appeared as potential competitors to source-to-source compilers at this level. In this paper, we present what we have identified as current challenges of source-to-source compilation of C and C++, as well as what we consider to be opportunities and possible directions forward. We also present several examples, implemented on top of the Clava source-to-source compiler, that use some of these ideas and techniques to raise the abstraction level of compiler research on complex compiled languages such as C or C++. The examples include automatic parallelization of for loops, high-level synthesis optimisation, hardware/software partitioning with run-time decisions, and automatic insertion of inline assembly for fast prototyping of custom instructions.
@InProceedings{bispo_et_al:OASIcs.PARMA-DITAM.2023.2, author = {Bispo, Jo\~{a}o and Paulino, Nuno and Sousa, Lu{\'\i}s Miguel}, title = {{Challenges and Opportunities in C/C++ Source-To-Source Compilation}}, booktitle = {14th Workshop on Parallel Programming and Run-Time Management Techniques for Many-Core Architectures and 12th Workshop on Design Tools and Architectures for Multicore Embedded Computing Platforms (PARMA-DITAM 2023)}, pages = {2:1--2:15}, series = {Open Access Series in Informatics (OASIcs)}, ISBN = {978-3-95977-269-3}, ISSN = {2190-6807}, year = {2023}, volume = {107}, editor = {Bispo, Jo\~{a}o and Charles, Henri-Pierre and Cherubin, Stefano and Massari, Giuseppe}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.PARMA-DITAM.2023.2}, URN = {urn:nbn:de:0030-drops-177225}, doi = {10.4230/OASIcs.PARMA-DITAM.2023.2}, annote = {Keywords: Source-to-source, compilation, transpilers, C/C++, code transformation} }
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