[flang][openacc] Fix function name resolution in acc routine

[clementval]

Summary

When acc routine is in a function, the first symbol resolved
was the function result and not the function name itself. It was
then failing the deferred attachment because the mangled name
had the entity attach to it. This patch fix the name resolution
for the function name in acc routine directive.

[clementval]

Remove comment

[razvanlupusoru]

Looks good. The comment is simply about not checking for compiler generated symbol.

flang/test/Lower/OpenACC/acc-routine.f90

5

I wonder if we should relax this part which check's acc.routine's symbol name - this name is not something guaranteed since it is synthetic name from compiler.

[clementval]

flang/test/Lower/OpenACC/acc-routine.f90

5

Do you mean the mangled name (_QPacc_routine10) or the acc.routine name _QPacc_routine10. The mangled name is guaranteed in flang and it's the only way to attach the acc.routine to the actual function. For the acc_routine_9 it is indeed also generated but since the attribute has it on the function I feel it is a nice check to have to make sure we attach the correct information to the correct routine.

flang/lib/Semantics/resolve-directives.cpp

Symbol::Flags accFlagsRequireMark{Symbol::Flag::AccCreate,
       Symbol::Flag::AccLink, Symbol::Flag::AccPresent};
 
   void PrivatizeAssociatedLoopIndex(const parser::OpenACCLoopConstruct &);
   void ResolveAccObjectList(const parser::AccObjectList &, Symbol::Flag);
   void ResolveAccObject(const parser::AccObject &, Symbol::Flag);
   Symbol *ResolveAcc(const parser::Name &, Symbol::Flag, Scope &);
   Symbol *ResolveAcc(Symbol &, Symbol::Flag, Scope &);
   Symbol *ResolveName(const parser::Name &, bool parentScope = false);
+  Symbol *ResolveFctName(const parser::Name &);
   Symbol *ResolveAccCommonBlockName(const parser::Name *);
   Symbol *DeclareOrMarkOtherAccessEntity(const parser::Name &, Symbol::Flag);
   Symbol *DeclareOrMarkOtherAccessEntity(Symbol &, Symbol::Flag);
   void CheckMultipleAppearances(
       const parser::Name &, const Symbol &, Symbol::Flag);
   void AllowOnlyArrayAndSubArray(const parser::AccObjectList &objectList);
   void DoNotAllowAssumedSizedArray(const parser::AccObjectList &objectList);
   void EnsureAllocatableOrPointer(
if (!prev && parentScope) {
     prev = currScope().parent().FindSymbol(name.source);
   }
   if (prev != name.symbol) {
     name.symbol = prev;
   }
   return prev;
 }
 
+Symbol *AccAttributeVisitor::ResolveFctName(const parser::Name &name) {
+  Symbol *prev{currScope().FindSymbol(name.source)};
+  if (!prev || (prev && prev->IsFuncResult())) {
+    prev = currScope().parent().FindSymbol(name.source);
+  }
+  if (prev != name.symbol) {
+    name.symbol = prev;
+  }
+  return prev;
+}
+
 template <typename T>
 common::IfNoLvalue<T, T> FoldExpr(
     evaluate::FoldingContext &foldingContext, T &&expr) {
   return evaluate::Fold(foldingContext, std::move(expr));
 }
 
 template <typename T>
 MaybeExpr EvaluateExpr(
if (symbol.has<SubprogramDetails>()) {
     }
     symbol.get<SubprogramDetails>().add_openACCRoutineInfo(info);
   }
 }
 
 bool AccAttributeVisitor::Pre(const parser::OpenACCRoutineConstruct &x) {
   const auto &optName{std::get<std::optional<parser::Name>>(x.t)};
   if (optName) {
-    if (Symbol *sym = ResolveName(*optName, true)) {
+    if (Symbol *sym = ResolveFctName(*optName)) {
       Symbol &ultimate{sym->GetUltimate()};
       AddRoutineInfoToSymbol(ultimate, x);
     } else {
       context_.Say((*optName).source,
           "No function or subroutine declared for '%s'"_err_en_US,
           (*optName).source);
     }
   } else {

flang/test/Lower/OpenACC/acc-routine.f90

 ! This test checks lowering of OpenACC routine directive.
 
 ! RUN: bbc -fopenacc -emit-fir %s -o - | FileCheck %s
 
+! CHECK: acc.routine @acc_routine_9 func(@_QPacc_routine10) seq
 ! CHECK: acc.routine @acc_routine_8 func(@_QPacc_routine9) bind("_QPacc_routine9a")
 ! CHECK: acc.routine @acc_routine_7 func(@_QPacc_routine8) bind("routine8_")
 ! CHECK: acc.routine @acc_routine_6 func(@_QPacc_routine7) gang(dim = 1 : i32)
 ! CHECK: acc.routine @acc_routine_5 func(@_QPacc_routine6) nohost
 ! CHECK: acc.routine @acc_routine_4 func(@_QPacc_routine5) worker
 ! CHECK: acc.routine @acc_routine_3 func(@_QPacc_routine4) vector
 ! CHECK: acc.routine @acc_routine_2 func(@_QPacc_routine3) gang
 ! CHECK: acc.routine @acc_routine_1 func(@_QPacc_routine2) seq

 subroutine acc_routine9a()
 end subroutine
 
 subroutine acc_routine9()
   !$acc routine bind(acc_routine9a)
 end subroutine
 
 ! CHECK-LABEL: func.func @_QPacc_routine9() attributes {acc.routine_info = #acc.routine_info<[@acc_routine_8]>}
+
+function acc_routine10()
+  !$acc routine(acc_routine10) seq
+end function
+
+! CHECK-LABEL: func.func @_QPacc_routine10() -> f32 attributes {acc.routine_info = #acc.routine_info<[@acc_routine_9]>}