[flang-commits] [flang] [Flang][OpenMP] Push context when parsing DECLARE VARIANT (PR #147075)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-flang-parser

@llvm/pr-subscribers-flang-semantics

Author: Jack Styles (Stylie777)

<details>
<summary>Changes</summary>

Basic parsing and semantics support for Declare Variant was added in #<!-- -->130578. However, this did not include variant of `Pre` and `Post` within `OmpAttributeVisitor`. This meant that when a function in the class tried to get the context using `GetContext`, Flang would crash as the context was empty. To ensure this is possible, such as when resolving names as part of the `uniform` clause in the `simd` directive, the context is now pushed within `OmpAttributeVisitor` when parsing a `DECLARE VARIANT` directive.

Fixes #<!-- -->145222

---
Full diff: https://github.com/llvm/llvm-project/pull/147075.diff


2 Files Affected:

- (modified) flang/lib/Semantics/resolve-directives.cpp (+6) 
- (modified) flang/test/Parser/OpenMP/declare-variant.f90 (+27) 


``````````diff
diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index 8d741734601a7..0d11b4a21ca3d 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -495,6 +495,12 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
   bool Pre(const parser::OpenMPAllocatorsConstruct &);
   void Post(const parser::OpenMPAllocatorsConstruct &);
 
+  bool Pre(const parser::OmpDeclareVariantDirective &x) {
+    PushContext(x.source, llvm::omp::Directive::OMPD_declare_variant);
+    return true;
+  }
+  void Post (const parser::OmpDeclareVariantDirective &) { PopContext(); };
+
   void Post(const parser::OmpObjectList &x) {
     // The objects from OMP clauses should have already been resolved,
     // except common blocks (the ResolveNamesVisitor does not visit
diff --git a/flang/test/Parser/OpenMP/declare-variant.f90 b/flang/test/Parser/OpenMP/declare-variant.f90
index 1b97733ea9525..3366b143e62e6 100644
--- a/flang/test/Parser/OpenMP/declare-variant.f90
+++ b/flang/test/Parser/OpenMP/declare-variant.f90
@@ -102,3 +102,30 @@ subroutine vsub(v1, v2)
     type(c_ptr), value :: v1, v2
   end
 end subroutine
+
+subroutine f
+  real :: x, y
+  y = 2
+  !omp simd
+  call f2(x, y)
+  !omp end simd 
+contains
+  subroutine f1 (x, y)
+    real :: x, y
+  end
+
+  subroutine f2 (x, y)
+    real :: x, y
+    !$omp declare variant (f1) match (construct={simd(uniform(y))})
+  end
+end subroutine
+!CHECK: !$OMP DECLARE VARIANT (f1) MATCH(CONSTRUCT={SIMD(UNIFORM(y))})
+!PARSE-TREE: | | | | DeclarationConstruct -> SpecificationConstruct -> OpenMPDeclarativeConstruct -> OmpDeclareVariantDirective
+!PARSE-TREE-NEXT: | | | | | Verbatim
+!PARSE-TREE-NEXT: | | | | | Name = 'f1'
+!PARSE-TREE-NEXT: | | | | | OmpClauseList -> OmpClause -> Match -> OmpMatchClause -> OmpContextSelectorSpecification -> OmpTraitSetSelector
+!PARSE-TREE-NEXT: | | | | | | OmpTraitSetSelectorName -> Value = Construct
+!PARSE-TREE-NEXT: | | | | | | OmpTraitSelector
+!PARSE-TREE-NEXT: | | | | | | | OmpTraitSelectorName -> Value = Simd
+!PARSE-TREE-NEXT: | | | | | | | Properties
+!PARSE-TREE-NEXT: | | | | | | | | OmpTraitProperty -> OmpClause -> Uniform -> Name = 'y'

``````````

</details>


https://github.com/llvm/llvm-project/pull/147075