[flang][OpenMP] Fix resolve common block in data-sharing clauses

The previous resolve only creates the host associated varaibles for
common block members, but does not replace the original objects with
the new created ones. Fix it and also compute the sizes and offsets
for the host common block members if they are host associated.

Reviewed By: kiranchandramohan

Differential Revision: https://reviews.llvm.org/D127214

flang/include/flang/Semantics/symbol.h

@@ -351,6 +351,10 @@ public:
   MutableSymbolVector &objects() { return objects_; }
   const MutableSymbolVector &objects() const { return objects_; }
   void add_object(Symbol &object) { objects_.emplace_back(object); }
+  void replace_object(Symbol &object, unsigned index) {
+    CHECK(index < (unsigned)objects_.size());
+    objects_[index] = object;
+  }
   std::size_t alignment() const { return alignment_; }
   void set_alignment(std::size_t alignment) { alignment_ = alignment; }
 

flang/lib/Semantics/compute-offsets.cpp

@@ -156,7 +156,7 @@ void ComputeOffsetsHelper::DoCommonBlock(Symbol &commonBlock) {
     Symbol &symbol{*object};
     auto errorSite{
         commonBlock.name().empty() ? symbol.name() : commonBlock.name()};
-    if (std::size_t padding{DoSymbol(symbol)}) {
+    if (std::size_t padding{DoSymbol(symbol.GetUltimate())}) {
       context_.Say(errorSite,
           "COMMON block /%s/ requires %zd bytes of padding before '%s' for alignment"_port_en_US,
           commonBlock.name(), padding, symbol.name());

flang/lib/Semantics/resolve-directives.cpp

@@ -1677,7 +1677,9 @@ void OmpAttributeVisitor::ResolveOmpObject(
               // 2.15.3 When a named common block appears in a list, it has the
               // same meaning as if every explicit member of the common block
               // appeared in the list
-              for (auto &object : symbol->get<CommonBlockDetails>().objects()) {
+              auto &details{symbol->get<CommonBlockDetails>()};
+              unsigned index{0};
+              for (auto &object : details.objects()) {
                 if (auto *resolvedObject{
                         ResolveOmp(*object, ompFlag, currScope())}) {
                   if (dataCopyingAttributeFlags.test(ompFlag)) {
@@ -1685,7 +1687,9 @@ void OmpAttributeVisitor::ResolveOmpObject(
                   } else {
                     AddToContextObjectWithDSA(*resolvedObject, ompFlag);
                   }
+                  details.replace_object(*resolvedObject, index);
                 }
+                index++;
               }
             } else {
               context_.Say(name.source, // 2.15.3

flang/test/Semantics/OpenMP/omp-common-block.f90

@@ -0,0 +1,18 @@
+! RUN: %flang_fc1 -fopenmp -fdebug-dump-symbols %s | FileCheck %s
+
+program main
+  !CHECK: a size=4 offset=0: ObjectEntity type: REAL(4)
+  !CHECK: b size=8 offset=4: ObjectEntity type: INTEGER(4) shape: 1_8:2_8
+  !CHECK: c size=4 offset=12: ObjectEntity type: REAL(4)
+  !CHECK: blk size=16 offset=0: CommonBlockDetails alignment=4: a b c
+  real :: a, c
+  integer :: b(2)
+  common /blk/ a, b, c
+  !$omp parallel private(/blk/)
+    !CHECK: OtherConstruct scope: size=0 alignment=1
+    !CHECK:   a (OmpPrivate): HostAssoc
+    !CHECK:   b (OmpPrivate): HostAssoc
+    !CHECK:   c (OmpPrivate): HostAssoc
+    call sub(a, b, c)
+  !$omp end parallel
+end program

flang/test/Semantics/OpenMP/omp-threadprivate04.f90

@@ -5,44 +5,45 @@
 
 program main
   integer :: i, N = 10
-  integer, save :: x
-  common /blk/ y
+  integer, save :: x1, x2, x3, x4, x5, x6, x7, x8, x9
+  common /blk1/ y1, /blk2/ y2, /blk3/ y3, /blk4/ y4, /blk5/ y5
 
-  !$omp threadprivate(x, /blk/)
+  !$omp threadprivate(x1, x2, x3, x4, x5, x6, x7, x8, x9)
+  !$omp threadprivate(/blk1/, /blk2/, /blk3/, /blk4/, /blk5/)
 
-  !$omp parallel num_threads(x)
+  !$omp parallel num_threads(x1)
   !$omp end parallel
 
-  !$omp single copyprivate(x, /blk/)
+  !$omp single copyprivate(x2, /blk1/)
   !$omp end single
 
-  !$omp do schedule(static, x)
+  !$omp do schedule(static, x3)
   do i = 1, N
-    y = x
+    y1 = x3
   end do
   !$omp end do
 
-  !$omp parallel copyin(x, /blk/)
+  !$omp parallel copyin(x4, /blk2/)
   !$omp end parallel
 
-  !$omp parallel if(x > 1)
+  !$omp parallel if(x5 > 1)
   !$omp end parallel
 
-  !$omp teams thread_limit(x)
+  !$omp teams thread_limit(x6)
   !$omp end teams
 
   !ERROR: A THREADPRIVATE variable cannot be in PRIVATE clause
   !ERROR: A THREADPRIVATE variable cannot be in PRIVATE clause
-  !$omp parallel private(x, /blk/)
+  !$omp parallel private(x7, /blk3/)
   !$omp end parallel
 
   !ERROR: A THREADPRIVATE variable cannot be in FIRSTPRIVATE clause
   !ERROR: A THREADPRIVATE variable cannot be in FIRSTPRIVATE clause
-  !$omp parallel firstprivate(x, /blk/)
+  !$omp parallel firstprivate(x8, /blk4/)
   !$omp end parallel
 
   !ERROR: A THREADPRIVATE variable cannot be in SHARED clause
   !ERROR: A THREADPRIVATE variable cannot be in SHARED clause
-  !$omp parallel shared(x, /blk/)
+  !$omp parallel shared(x9, /blk5/)
   !$omp end parallel
 end