[flang] Procedure pointers are not descriptors

[klausler]

Summary

Code in Evaluate/type.cpp was maintaining a very old assumption that
procedure pointers would need to be represented as descriptors. This
is not the case -- they are code or thunk addresses.

[jeanPerier]

LGTM

flang/lib/Evaluate/type.cpp

for (const ShapeSpec &shapeSpec : details.shape()) {
     const auto &ub{shapeSpec.ubound().GetExplicit()};
     if (!lb || !ub || !IsConstantExpr(*lb) || !IsConstantExpr(*ub)) {
       return true;
     }
   }
   return false;
 }
 
-static bool IsDescriptor(const ProcEntityDetails &details) {
-  // TODO: refine this placeholder; procedure pointers and dummy
-  // procedures should now be simple addresses (possibly of thunks)
-  return details.HasExplicitInterface();
-}
-
 bool IsDescriptor(const Symbol &symbol) {
   return common::visit(
       common::visitors{
           [&](const ObjectEntityDetails &d) {
             return IsAllocatableOrPointer(symbol) || IsDescriptor(d);
           },
-          [&](const ProcEntityDetails &d) {
-            return (symbol.attrs().test(Attr::POINTER) ||
-                       symbol.attrs().test(Attr::EXTERNAL)) &&
-                IsDescriptor(d);
-          },
+          [&](const ProcEntityDetails &d) { return false; },
           [&](const EntityDetails &d) { return IsDescriptor(d.type()); },
           [](const AssocEntityDetails &d) {
             if (const auto &expr{d.expr()}) {
               if (expr->Rank() > 0) {
                 return true;
               }
               if (const auto dynamicType{expr->GetType()}) {
                 if (dynamicType->RequiresDescriptor()) {

flang/test/Semantics/data05.f90

type :: t1(kind,len)
     character(kind=5-kind) :: c(2)
     real(kind=kind), pointer :: xp(:,:)
     procedure(ifunc), pointer, nopass :: ifptr
     procedure(rfunc), pointer, nopass :: rp
     procedure(real), pointer, nopass :: xrp
   end type
  contains
   subroutine s1
-    procedure(ifunc), pointer :: ifptr ! CHECK: ifptr, EXTERNAL, POINTER (Function, InDataStmt) size=24 offset=0: ProcEntity ifunc => ifunc
+    procedure(ifunc), pointer :: ifptr ! CHECK: ifptr, EXTERNAL, POINTER (Function, InDataStmt) size=8 offset=0: ProcEntity ifunc => ifunc
     data ifptr/ifunc/
   end subroutine
   subroutine s2
     integer(kind=1) :: j1 ! CHECK: j1 (InDataStmt) size=1 offset=0: ObjectEntity type: INTEGER(1) init:66_1
     data j1/66/
   end subroutine
   subroutine s3
     integer :: jd ! CHECK: jd (InDataStmt) size=4 offset=0: ObjectEntity type: INTEGER(4) init:666_4
subroutine s7
     data (zv(j), j=1,0,-1)/(5,6),(3,4)/
     data (zv(j)%im, zv(j)%re, j=-1,-1,-9)/2,1/
   end subroutine
   real function rfunc2(x)
     real, intent(in) :: x
     rfunc2 = x + 1.
   end function
   subroutine s8
-    procedure(rfunc), pointer :: rfptr ! CHECK: rfptr, EXTERNAL, POINTER (Function, InDataStmt) size=24 offset=0: ProcEntity rfunc => rfunc2
+    procedure(rfunc), pointer :: rfptr ! CHECK: rfptr, EXTERNAL, POINTER (Function, InDataStmt) size=8 offset=0: ProcEntity rfunc => rfunc2
     data rfptr/rfunc2/
   end subroutine
   subroutine s10
     real, target, save :: arr(3,4) ! CHECK: arr, SAVE, TARGET size=48 offset=0: ObjectEntity type: REAL(4) shape: 1_8:3_8,1_8:4_8
     real, pointer :: xpp(:,:) ! CHECK: xpp, POINTER (InDataStmt) size=72 offset=48: ObjectEntity type: REAL(4) shape: :,: init:arr
     data xpp/arr/
   end subroutine
   integer function ifunc2(n)
     integer, intent(in) :: n
     ifunc2 = n + 1
   end function
   subroutine s11
     real, target, save :: arr(3,4) ! CHECK: arr, SAVE, TARGET size=48 offset=0: ObjectEntity type: REAL(4) shape: 1_8:3_8,1_8:4_8
-    type(t1) :: d1 = t1(1,reshape([1,2,3,4],[2,2]),(6.,7.),.false.,'ab',arr,ifunc2,rfunc,extrfunc) ! CHECK: d1 size=168 offset=48: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(j=1_4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),z=(6._4,7._4),t=.false._4,c=[CHARACTER(KIND=1,LEN=1)::"a","a"],xp=arr,ifptr=ifunc2,rp=rfunc,xrp=extrfunc)
+    type(t1) :: d1 = t1(1,reshape([1,2,3,4],[2,2]),(6.,7.),.false.,'ab',arr,ifunc2,rfunc,extrfunc) ! CHECK: d1 size=136 offset=48: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(j=1_4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),z=(6._4,7._4),t=.false._4,c=[CHARACTER(KIND=1,LEN=1)::"a","a"],xp=arr,ifptr=ifunc2,rp=rfunc,xrp=extrfunc)
     type(t1(4,len=1)) :: d2 = t1(4)(xrp=extrfunc,rp=rfunc,ifptr=ifunc2,xp=arr,c='a&
-      &b',t=.false.,z=(6.,7.),x=reshape([1,2,3,4],[2,2]),j=1) ! CHECK: d2 size=168 offset=216: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(j=1_4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),z=(6._4,7._4),t=.false._4,c=[CHARACTER(KIND=1,LEN=1)::"a","a"],xp=arr,ifptr=ifunc2,rp=rfunc,xrp=extrfunc)
-    type(t1(2+2)) :: d3 ! CHECK: d3 (InDataStmt) size=168 offset=384: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(j=1_4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),z=(6._4,7._4),t=.false._4,c=[CHARACTER(KIND=1,LEN=1)::"a","a"],xp=arr,ifptr=ifunc2,rp=rfunc,xrp=extrfunc)
+      &b',t=.false.,z=(6.,7.),x=reshape([1,2,3,4],[2,2]),j=1) ! CHECK: d2 size=136 offset=184: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(j=1_4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),z=(6._4,7._4),t=.false._4,c=[CHARACTER(KIND=1,LEN=1)::"a","a"],xp=arr,ifptr=ifunc2,rp=rfunc,xrp=extrfunc)
+    type(t1(2+2)) :: d3 ! CHECK: d3 (InDataStmt) size=136 offset=320: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(j=1_4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),z=(6._4,7._4),t=.false._4,c=[CHARACTER(KIND=1,LEN=1)::"a","a"],xp=arr,ifptr=ifunc2,rp=rfunc,xrp=extrfunc)
     data d3/t1(1,reshape([1,2,3,4],[2,2]),(6.,7.),.false.,'ab',arr,ifunc2,rfunc,extrfunc)/
-    type(t1) :: d4 ! CHECK: d4 (InDataStmt) size=168 offset=552: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(j=1_4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),z=(6._4,7._4),t=.false._4,c=[CHARACTER(KIND=1,LEN=1)::"a","a"],xp=arr,ifptr=ifunc2,rp=rfunc,xrp=extrfunc)
+    type(t1) :: d4 ! CHECK: d4 (InDataStmt) size=136 offset=456: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(j=1_4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),z=(6._4,7._4),t=.false._4,c=[CHARACTER(KIND=1,LEN=1)::"a","a"],xp=arr,ifptr=ifunc2,rp=rfunc,xrp=extrfunc)
     data d4/t1(4)(xrp=extrfunc,rp=rfunc,ifptr=ifunc2,xp=arr,c='ab',t=.false.,z=(6&
       &.,7.),x=reshape([1,2,3,4],[2,2]),j=1)/
-    type(t1) :: d5 ! CHECK: d5 (InDataStmt) size=168 offset=720: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(j=1_4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),z=(6._4,7._4),t=.false._4,c=[CHARACTER(KIND=1,LEN=1)::"a","b"],xp=arr,ifptr=ifunc2,rp=rfunc,xrp=extrfunc)
+    type(t1) :: d5 ! CHECK: d5 (InDataStmt) size=136 offset=592: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(j=1_4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),z=(6._4,7._4),t=.false._4,c=[CHARACTER(KIND=1,LEN=1)::"a","b"],xp=arr,ifptr=ifunc2,rp=rfunc,xrp=extrfunc)
     data d5%j/1/,d5%x/1,2,3,4/,d5%z%re/6./,d5%z%im/7./,d5%t/.false./,d5%c(1:1)/'a'/,d5%c(2:&
       &2)/'b'/,d5%xp/arr/,d5%ifptr/ifunc2/,d5%rp/rfunc/,d5%xrp/extrfunc/
   end subroutine
   subroutine s12
-    procedure(rfunc), pointer :: pp ! CHECK: pp, EXTERNAL, POINTER (Function, InDataStmt) size=24 offset=0: ProcEntity rfunc => rfunc2
+    procedure(rfunc), pointer :: pp ! CHECK: pp, EXTERNAL, POINTER (Function, InDataStmt) size=8 offset=0: ProcEntity rfunc => rfunc2
     data pp/rfunc2/
   end subroutine
 end module

flang/test/Semantics/typeinfo01.f90

 module m05
   type :: t
     procedure(s1), pointer :: p1 => s1
   end type
  contains
   subroutine s1(x)
     class(t), intent(in) :: x
   end subroutine
-!CHECK: .dt.t, SAVE, TARGET (CompilerCreated, ReadOnly): ObjectEntity type: TYPE(derivedtype) init:derivedtype(binding=NULL(),name=.n.t,sizeinbytes=24_8,uninstantiated=NULL(),kindparameter=NULL(),lenparameterkind=NULL(),component=NULL(),procptr=.p.t,special=NULL(),specialbitset=0_4,hasparent=0_1,noinitializationneeded=0_1,nodestructionneeded=1_1,nofinalizationneeded=1_1)
+!CHECK: .dt.t, SAVE, TARGET (CompilerCreated, ReadOnly): ObjectEntity type: TYPE(derivedtype) init:derivedtype(binding=NULL(),name=.n.t,sizeinbytes=8_8,uninstantiated=NULL(),kindparameter=NULL(),lenparameterkind=NULL(),component=NULL(),procptr=.p.t,special=NULL(),specialbitset=0_4,hasparent=0_1,noinitializationneeded=0_1,nodestructionneeded=1_1,nofinalizationneeded=1_1)
 !CHECK: .p.t, SAVE, TARGET (CompilerCreated, ReadOnly): ObjectEntity type: TYPE(procptrcomponent) shape: 0_8:0_8 init:[procptrcomponent::procptrcomponent(name=.n.p1,offset=0_8,initialization=s1)]
 end module
 
 module m06
   type :: t
    contains
     procedure :: s1
     generic :: assignment(=) => s1