Allow any expression as message

Author: Leporacanthicus

flang/include/flang/Parser/parse-tree.h

@@ -4019,7 +4019,7 @@ struct OmpMapClause {
 // message-clause ->
 //    MESSAGE("message-text")
 struct OmpMessageClause {
-  WRAPPER_CLASS_BOILERPLATE(OmpMessageClause, std::string);
+  WRAPPER_CLASS_BOILERPLATE(OmpMessageClause, Expr);
 };
 
 // Ref: [4.5:87-91], [5.0:140-146], [5.1:166-171], [5.2:270]

flang/lib/Parser/openmp-parsers.cpp

@@ -515,7 +515,7 @@ TYPE_PARSER(construct<OmpSeverityClause>(
     "FATAL" >> pure(OmpSeverityClause::Severity::Fatal) ||
     "WARNING" >> pure(OmpSeverityClause::Severity::Warning)))
 
-TYPE_PARSER(construct<OmpMessageClause>(charLiteralConstantWithoutKind))
+TYPE_PARSER(construct<OmpMessageClause>(expr))
 
 TYPE_PARSER(
     "ACQUIRE" >> construct<OmpClause>(construct<OmpClause::Acquire>()) ||

flang/lib/Parser/unparse.cpp

@@ -2652,9 +2652,7 @@ class UnparseVisitor {
     EndOpenMP();
   }
   bool Pre(const OmpMessageClause &x) {
-    Word("\"");
     Walk(x.v);
-    Put("\"");
     return false;
   }
   void Unparse(const OpenMPErrorConstruct &x) {

flang/test/Parser/OpenMP/error-unparse.f90

@@ -1,5 +1,10 @@
 ! RUN: %flang_fc1  -fopenmp-version=51 -fopenmp -fdebug-unparse-no-sema %s 2>&1 | FileCheck %s
 program main
+  character(*), parameter :: message = "This is an error"
   !CHECK: !$OMP ERROR AT(COMPILATION) SEVERITY(WARNING) MESSAGE("some message here")
   !$omp error at(compilation) severity(warning) message("some message here")
+  !CHECK: !$OMP ERROR AT(COMPILATION) SEVERITY(FATAL) MESSAGE(message)
+  !$omp error at(compilation) severity(fatal) message(message)
+  !CHECK: !$OMP ERROR AT(EXECUTION) SEVERITY(FATAL) MESSAGE(message)
+  !$omp error at(EXECUTION) severity(fatal) message(message)
 end program main