PsycheC is a compiler frontend infrastructure for the C language that is enabled with an ML / Haskell-style (unification-based) type inference engine.This online interfaceillustrates the essential functionality of PsycheC.
Requirements
- Cmake
- C 14 compiler
- Haskell Stack
- Python 3
cmake CMakeLists.txt makeRunning the Tests
./ psychecgen -t ./CompileTests.sh cd solver && stack testThe simplest way to use PsycheC is through theCnippetcompiler adapter. Let us see an example. *******
Consider the filenode.cBelow.
//node.cvoid(f) () { T v=0; v ->value=42; v ->next=v; }
If you were to compilenode.cwith GCC / Clang, you would issue a command similar to this one:
gcc -c node. c
As a result, an object filenode.owould have been produced. However, this will not happen, since a declaration forTis not available. Instead, you will get an “undeclared identifier” error.
Now, if you invoke Cnippet, the compilation succeeds (flag- fis for non-commercial use).
./ cnip.sh -f gcc -c node.c
That is because, under the hood, PsycheC will infer the necessary missing definitions.
typedefstructTYPE_1__ { intvalue; structTYPE_1 __ * next; } * T;
This is a work-in-progress, feedback is welcome throughthis form.
PsycheC provides an alternative tovoid *and# macrosfor writing generic code in C. This is how you would implement a generic linked-list’sprependfunction.
_ GenericvoidPrepend(_ Forall (node_t) ** head, _Forall (value_t) value) { node_t* n=malloc( (sizeof) (node_t)); n ->value=value; n ->next=* head; * head=n; }
It is not necessary to define neithernode_tnorvalue_t. The definition ofprependapplies “for all” kinds of nodes and values. This way, you can focus on thealgorithms(the essence of generic programming).
Let us create 2 lists, one ofintand another ofpoint_t, and insert an new head to them.
int(main) () { _ Exists(node_t) * ilst=(0) ; Prepend(& ilst,42); _ Exists(node_t) * plst=(0) ; struct(point_tp; P.x=p.y=42; Prepend(& plst, p); }
Now, PsycheC infers that there “exists” a (node) type whose value is anint, together with an specialization ofprependfor such arguments. A different (node) type forpoint_t“exists” too, with its corresponding specialization ofprepend.
Check the examples directory forthis snippet.
Publications
PsycheC is an ongoing research project. It has been presented at:
- Inference of static semantics for incomplete C programs; Proceedings of the ACM on Programming Languages, Volume 2 Issue (POPL) **************************************** (Principles of Programming Languages) ), January 2018, Article No. 29.
Below is a list of papers whose developed tooling rely on PsycheC:
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Generation of in-bounds inputs for arrays in memory-unsafe languages ; Proceedings of the (IEEE / ACM International Symposium on) CGO(Code Generation and Optimization), February 2019, Pages 136 – 148.
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Automatic annotation of tasks in structured code; Proceedings of the 27 th International Conference on (PACT) (Parallel Architectures and Compilation Techniques), November 2018, Article No. 31.
This is an online article about PsycheC:
//node.cvoid(f) () { T v=0; v ->value=42; v ->next=v; }
gcc -c node. cTis not available. Instead, you will get an “undeclared identifier” error.- fis for non-commercial use)../ cnip.sh -f gcc -c node.ctypedefstructTYPE_1__ { intvalue; structTYPE_1 __ * next; } * T;
void *and# macrosfor writing generic code in C. This is how you would implement a generic linked-list’sprependfunction._ GenericvoidPrepend(_ Forall (node_t) ** head, _Forall (value_t) value) { node_t* n=malloc( (sizeof) (node_t)); n ->value=value; n ->next=* head; * head=n; }
node_tnorvalue_t. The definition ofprependapplies “for all” kinds of nodes and values. This way, you can focus on thealgorithms(the essence of generic programming).intand another ofpoint_t, and insert an new head to them.int(main) () { _ Exists(node_t) * ilst=(0) ; Prepend(& ilst,42); _ Exists(node_t) * plst=(0) ; struct(point_tp; P.x=p.y=42; Prepend(& plst, p); }
int, together with an specialization ofprependfor such arguments. A different (node) type forpoint_t“exists” too, with its corresponding specialization ofprepend.Generation of in-bounds inputs for arrays in memory-unsafe languages ; Proceedings of the (IEEE / ACM International Symposium on) CGO(Code Generation and Optimization), February 2019, Pages 136 – 148.
Automatic annotation of tasks in structured code; Proceedings of the 27 th International Conference on (PACT) (Parallel Architectures and Compilation Techniques), November 2018, Article No. 31.
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