OpenMP validation boundaries

The OpenMP specification defines syntax restrictions as well as rules that depend on an enclosing program. ROUP separates those two categories without silently skipping either one.

For the normative rules, consult the relevant directive and clause sections in the OpenMP 6.0 specification or the earlier specification that introduced historical syntax.

Checked by every parse

OpenMpParser::parse checks everything that can be decided from one directive and its configured profiles, including:

• source-form, sentinel, continuation, UTF-8, and trailing-input validity;
• complete directive, parameter, clause, and modifier syntax, plus the explicitly supported typed host-expression grammar;
• feature introduction for the selected OpenMP and host-language versions;
• directive-clause compatibility and duplicate singleton clauses;
• structurally invalid nested directives and selectors; and
• other context-independent restrictions represented by the validator.

Failure returns one structured Diagnostic. A parse never returns a partial AST, recovery node, warning-only substitute, or guessed default. Host-language constructs outside the documented typed expression grammar are also hard errors; ROUP does not claim to replace a complete C, C++, or Fortran frontend.

Facts supplied by an embedding compiler

Some specification rules require information outside the directive text, such as declaration placement, construct association, name resolution, or whether a host expression is constant. Use OpenMpParser::parse_with_facts when those checks apply.

Facts required by the parsed construct are mandatory. A missing fact is a hard diagnostic rather than permission to bypass the check. The compiler remains responsible for producing truthful facts from its program representation.

Stateful region validation

ContextValidator validates directive sequences whose correctness depends on previous input, including begin/end pairing and association state. Opening and closing locations use checked spans, so mismatches can report the related source location.

Contributor rule

When adding standardized syntax, record its introduction version, construct a fully typed payload, implement all context-independent restrictions, identify every required external fact, and add both positive and negative public-API tests. Do not add a permissive grammar branch while deferring malformed states to a renderer or compatibility adapter.