Reconciling high-level optimizations and low-level code in LLVM
| Autor: | John Regehr, June-Young Lee, Zhengyang Liu, Nuno P. Lopes, Ralf Jung, Chung-Kil Hur |
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| Rok vydání: | 2018 |
| Předmět: |
Intermediate language
Programming language Computer science Semantics (computer science) 020207 software engineering 0102 computer and information sciences 02 engineering and technology computer.software_genre 01 natural sciences 010201 computation theory & mathematics 0202 electrical engineering electronic engineering information engineering Code (cryptography) Memory model Compiler Safety Risk Reliability and Quality computer Software Rust (programming language) computer.programming_language |
| Zdroj: | Proceedings of the ACM on Programming Languages. 2:1-28 |
| ISSN: | 2475-1421 |
| Popis: | LLVM miscompiles certain programs in C, C++, and Rust that use low-level language features such as raw pointers in Rust or conversion between integers and pointers in C or C++. The problem is that it is difficult for the compiler to implement aggressive, high-level memory optimizations while also respecting the guarantees made by the programming languages to low-level programs. A deeper problem is that the memory model for LLVM's intermediate representation (IR) is informal and the semantics of corner cases are not always clear to all compiler developers. We developed a novel memory model for LLVM IR and formalized it. The new model requires a handful of problematic IR-level optimizations to be removed, but it also supports the addition of new optimizations that were not previously legal. We have implemented the new model and shown that it fixes known memory-model-related miscompilations without impacting the quality of generated code. |
| Databáze: | OpenAIRE |
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