• Corpus ID: 15412934

Subtleties of the ANSI / ISO C standard

@inproceedings{Krebbers2012SubtletiesOT,
  title={Subtleties of the ANSI / ISO C standard},
  author={Robbert Krebbers and Freek Wiedijk},
  year={2012}
}
In our Formalin project to formalize C11 (the ANSI/ISO standard of the C programming language) we discovered many subtleties that make formalization of this standard difficult. We discuss some of these subtleties and indicate how they may be addressed in a formal C semantics. Furthermore, we argue that the C standard does not allow Turing complete implementations, and that its evaluation semantics does not preserve typing. Finally, we claim that no strictly conforming programs exist. That is… 
open-std.org
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References

SHOWING 1-10 OF 27 REFERENCES
A Formalization of the C99 Standard in HOL, Isabelle and Coq
TLDR
The Formalin project to create a formal version of the C99 standard for the C programming language, which means that the C preprocessor, the C standard library, floating point arithmetic, and 'dirty' C features like signal handling and volatile variables are treated.
Mechanized Semantics for the Clight Subset of the C Language
TLDR
The formal semantics of a large subset of the C language called Clight is presented, which includes pointer arithmetic, struct and union types, C loops and structured switch statements, and is mechanized using the Coq proof assistant.
A Formal Semantics for the C Programming Language
TLDR
A formal denotational semantics for the ANSI C programming language is proposed, with emphasis on its accuracy and completeness with respect to the standard, and is demonstrated that a programming language as useful in practice and as inherently complicated as C can nonetheless be defined formally.
An executable formal semantics of C with applications
TLDR
The semantics is shown capable of automatically finding program errors, both statically and at runtime, and it is also used to enumerate nondeterministic behavior.
seL4: formal verification of an OS kernel
TLDR
To the knowledge, this is the first formal proof of functional correctness of a complete, general-purpose operating-system kernel.
Undefined behavior: what happened to my code?
TLDR
It is argued that the research community should help address the problems that arise from undefined behavior, and not dismiss them as esoteric C implementation issues, because they do happen in real-world systems.
Formal Verification of a C-like Memory Model and Its Uses for Verifying Program Transformations
TLDR
This article presents the formal verification, using the Coq proof assistant, of a memory model for low-level imperative languages such as C and compiler intermediate languages that supports reasoning over transformations of such programs.
VCC: A Practical System for Verifying Concurrent C
TLDR
This paper motivates VCC, describes the verification methodology, the architecture of VCC is described, and the experience using VCC to verify the Microsoft Hyper-V hypervisor is reported on.
Compiler verification in the context of pervasive system verification
This thesis presents the formal verification of the compiling specification for a simple, non-optimizing compiler from the C-like programming language C0 to VAMP assembly code. The main result is a…
Finding and understanding bugs in C compilers
TLDR
Csmith, a randomized test-case generation tool, is created and spent three years using it to find compiler bugs, and a collection of qualitative and quantitative results about the bugs it found are presented.
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