[flang] Sort symbols by creation order

[PeteSteinfeld]

Summary

We have a "<" operator defined on the type semantics::Symbol that's based on
the symbols' locations in the cooked character stream. This is potentially
problematic when comparing symbols from .mod files when the cooked character
streams themselves might be allocated to varying memory locations.

This change fixes that by using the order in which symbols are created as the
basis for the "<" operator. Thanks to Tim and Peter for consultation on the
necessity of doing this and the idea for what to use as the basis of the sort.

This change in the "<" operator changed the expected results for three of the
tests. I manually inspected the new results, and they look OK to me. The
differences in data05.f90 and typeinfo01.f90 are entirely the order, offsets,
and sizes of the derived type components. The changes in resolve102.f90 are
due to the new, different "<" operator used for sorting.

[tskeith]

flang/include/flang/Semantics/symbol.h

599–600

There isn't anything specific to maps about this so I think the comment just "collate symbols by creation order".

658

It would make more sense to put nameCount_ in Symbols. And symbolCount_ would be a better name.

[PeteSteinfeld]

Responding to Tim's comments. I moved the data member from "Symbol" to
"Symbols" and renamed it "symbolCount_". Since "Symbols" is a template class,
this meant that I could initialize it directly in the class definition rather
than in the .cpp file.

[PeteSteinfeld]

flang/include/flang/Semantics/symbol.h

658

Great suggestions. And for reasons I don't understand, I can initialize static data members directly in the definition of a template class.

[tskeith]

flang/include/flang/Semantics/symbol.h

703

This doesn't need to be static.

[PeteSteinfeld]

flang/include/flang/Semantics/symbol.h

703

Thanks, Tim. I'll change this.

[klausler]

flang/include/flang/Semantics/symbol.h

703

It need not be static today, since there's just one static instance of this class; but there would be a subtle bug in the future if this member were not static and somebody needed another Symbol allocator instance for inlining or whatever.

[PeteSteinfeld]

flang/include/flang/Semantics/symbol.h

703

Good point, Peter. I'll fix this in a follow-in update.

flang/include/flang/Semantics/symbol.h

return std::visit(common::visitors{
                           [](const auto &) { return false; },
                       },
         details_);
   }
 
   bool operator==(const Symbol &that) const { return this == &that; }
   bool operator!=(const Symbol &that) const { return !(*this == that); }
   bool operator<(const Symbol &that) const {
-    // For maps of symbols: collate them by source location
-    return name_.begin() < that.name_.begin();
+    // Used to collate symbols by creation order
+    return sortIndex_ < that.sortIndex_;
   }
 
   int Rank() const {
     return std::visit(
         common::visitors{
             [](const SubprogramDetails &sd) {
               return sd.isFunction() ? sd.result().Rank() : 0;
             },
public:
   // If there is a parent component, return a pointer to its derived type spec.
   // The Scope * argument defaults to this->scope_ but should be overridden
   // for a parameterized derived type instantiation with the instance's scope.
   const DerivedTypeSpec *GetParentTypeSpec(const Scope * = nullptr) const;
 
 private:
   const Scope *owner_;
   SourceName name_;
+  std::size_t sortIndex_; // to implement "operator<" platform independently
   Attrs attrs_;
   Flags flags_;
   Scope *scope_{nullptr};
   std::size_t size_{0}; // size in bytes
   std::size_t offset_{0}; // byte offset in scope or common block
   Details details_;
 
   Symbol() {} // only created in class Symbols
   const std::string GetDetailsName() const;

 // deleted.
 template <std::size_t BLOCK_SIZE> class Symbols {
 public:
   Symbol &Make(const Scope &owner, const SourceName &name, const Attrs &attrs,
       Details &&details) {
     Symbol &symbol = Get();
     symbol.owner_ = &owner;
     symbol.name_ = name;
+    symbol.sortIndex_ = ++symbolCount_;
     symbol.attrs_ = attrs;
     symbol.details_ = std::move(details);
     return symbol;
   }
 
 private:
   using blockType = std::array<Symbol, BLOCK_SIZE>;
   std::list<blockType *> blocks_;
   std::size_t nextIndex_{0};
   blockType *currBlock_{nullptr};
+  static inline std::size_t symbolCount_ = 0;
 
   Symbol &Get() {
     if (nextIndex_ == 0) {
       blocks_.push_back(new blockType());
       currBlock_ = blocks_.back();
     }
     Symbol &result = (*currBlock_)[nextIndex_];
     if (++nextIndex_ >= BLOCK_SIZE) {

flang/test/Semantics/data05.f90

subroutine s10
     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=184 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=192 offset=48: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(c=[CHARACTER(KIND=1,LEN=1)::"a","a"],ifptr=ifunc2,j=1_4,rp=rfunc,t=.false._4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),xp=arr,xrp=extrfunc,z=(6._4,7._4))
     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=184 offset=232: 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=184 offset=416: 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=192 offset=240: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(c=[CHARACTER(KIND=1,LEN=1)::"a","a"],ifptr=ifunc2,j=1_4,rp=rfunc,t=.false._4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),xp=arr,xrp=extrfunc,z=(6._4,7._4))
+    type(t1(2+2)) :: d3 ! CHECK: d3 (InDataStmt) size=192 offset=432: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(c=[CHARACTER(KIND=1,LEN=1)::"a","a"],ifptr=ifunc2,j=1_4,rp=rfunc,t=.false._4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),xp=arr,xrp=extrfunc,z=(6._4,7._4))
     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=184 offset=600: 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=192 offset=624: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(c=[CHARACTER(KIND=1,LEN=1)::"a","a"],ifptr=ifunc2,j=1_4,rp=rfunc,t=.false._4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),xp=arr,xrp=extrfunc,z=(6._4,7._4))
     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=184 offset=784: 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=192 offset=816: ObjectEntity type: TYPE(t1(kind=4_1,len=1_2)) init:t1(kind=4_1,len=1_2)(c=[CHARACTER(KIND=1,LEN=1)::"a","b"],ifptr=ifunc2,j=1_4,rp=rfunc,t=.false._4,x=reshape([REAL(4)::1._4,2._4,3._4,4._4],shape=[2,2]),xp=arr,xrp=extrfunc,z=(6._4,7._4))
     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
     data pp/rfunc2/
   end subroutine
 end module

flang/test/Semantics/resolve102.f90

 ! RUN: %S/test_errors.sh %s %t %f18
 
 ! Tests for circularly defined procedures
 !ERROR: Procedure 'sub' is recursively defined.  Procedures in the cycle: 'sub', 'p2'
 subroutine sub(p2)
   PROCEDURE(sub) :: p2
 
   call sub()
 end subroutine
 
 subroutine circular
-  !ERROR: Procedure 'p' is recursively defined.  Procedures in the cycle: 'p', 'sub', 'p2'
+  !ERROR: Procedure 'p' is recursively defined.  Procedures in the cycle: 'sub', 'p', 'p2'
   procedure(sub) :: p
 
   call p(sub)
 
   contains
     subroutine sub(p2)
       procedure(p) :: p2
     end subroutine
 end subroutine circular
 
 program iface
-  !ERROR: Procedure 'p' is recursively defined.  Procedures in the cycle: 'p', 'sub', 'p2'
+  !ERROR: Procedure 'p' is recursively defined.  Procedures in the cycle: 'sub', 'p', 'p2'
   procedure(sub) :: p
   interface
     subroutine sub(p2)
       import p
       procedure(p) :: p2
     end subroutine
   end interface
   call p(sub)
 end program
 
 Program mutual
   Procedure(sub1) :: p
 
   Call p(sub)
 
   contains
-    !ERROR: Procedure 'sub1' is recursively defined.  Procedures in the cycle: 'p', 'sub1', 'arg'
+    !ERROR: Procedure 'sub1' is recursively defined.  Procedures in the cycle: 'sub1', 'p', 'arg'
     Subroutine sub1(arg)
       procedure(sub1) :: arg
     End Subroutine
 
     Subroutine sub(p2)
       Procedure(sub1) :: p2
     End Subroutine
 End Program
 
 Program mutual1
   Procedure(sub1) :: p
 
   Call p(sub)
 
   contains
-    !ERROR: Procedure 'sub1' is recursively defined.  Procedures in the cycle: 'p', 'sub1', 'arg', 'sub', 'p2'
+    !ERROR: Procedure 'sub1' is recursively defined.  Procedures in the cycle: 'sub1', 'sub', 'p', 'arg', 'p2'
     Subroutine sub1(arg)
       procedure(sub) :: arg
     End Subroutine
 
     Subroutine sub(p2)
       Procedure(sub1) :: p2
     End Subroutine
 End Program

flang/test/Semantics/typeinfo01.f90

type :: t(len)
     real :: automatic(len)
   end type
 !CHECK: .dt.t, SAVE, TARGET: ObjectEntity type: TYPE(derivedtype) init:derivedtype(name=.n.t,parent=NULL(),uninstantiated=NULL(),kindparameter=NULL(),lenparameterkind=.lpk.t)
 !CHECK: .lpk.t, SAVE, TARGET: ObjectEntity type: INTEGER(1) shape: 0_8:0_8 init:[INTEGER(1)::8_1]
  contains
   subroutine s1(x)
 !CHECK: .b.t.1.allocatable, SAVE, TARGET: ObjectEntity type: TYPE(value) shape: 0_8:1_8,0_8:0_8 init:reshape([value::value(genre=1_1,value=0_8),value(genre=1_1,value=0_8)],shape=[2,1])
 !CHECK: .b.t.1.automatic, SAVE, TARGET: ObjectEntity type: TYPE(value) shape: 0_8:1_8,0_8:0_8 init:reshape([value::value(genre=2_1,value=1_8),value(genre=3_1,value=0_8)],shape=[2,1])
-!CHECK: .c.t.1, SAVE, TARGET: ObjectEntity type: TYPE(component) shape: 0_8:3_8 init:[component::component(name=.n.allocatable,genre=3_1,category=1_1,kind=4_1,rank=1_1,offset=0_8,characterlen=value(genre=1_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=.b.t.1.allocatable,initialization=NULL()),component(name=.n.automatic,genre=4_1,category=1_1,kind=4_1,rank=1_1,offset=96_8,characterlen=value(genre=1_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=.b.t.1.automatic,initialization=NULL()),component(name=.n.chauto,genre=4_1,category=3_1,kind=1_1,rank=0_1,offset=72_8,characterlen=value(genre=3_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=NULL(),initialization=NULL()),component(name=.n.pointer,genre=2_1,category=1_1,kind=4_1,rank=0_1,offset=48_8,characterlen=value(genre=1_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=NULL(),initialization=target)]
+!CHECK: .c.t.1, SAVE, TARGET: ObjectEntity type: TYPE(component) shape: 0_8:3_8 init:[component::component(name=.n.allocatable,genre=3_1,category=1_1,kind=4_1,rank=1_1,offset=0_8,characterlen=value(genre=1_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=.b.t.1.allocatable,initialization=NULL()),component(name=.n.automatic,genre=4_1,category=1_1,kind=4_1,rank=1_1,offset=48_8,characterlen=value(genre=1_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=.b.t.1.automatic,initialization=NULL()),component(name=.n.chauto,genre=4_1,category=3_1,kind=1_1,rank=0_1,offset=96_8,characterlen=value(genre=3_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=NULL(),initialization=NULL()),component(name=.n.pointer,genre=2_1,category=1_1,kind=4_1,rank=0_1,offset=120_8,characterlen=value(genre=1_1,value=0_8),derived=NULL(),lenvalue=NULL(),bounds=NULL(),initialization=target)]
 !CHECK: .dt.t.1, SAVE, TARGET: ObjectEntity type: TYPE(derivedtype) init:derivedtype(binding=NULL(),name=.n.t,sizeinbytes=144_8,parent=NULL(),uninstantiated=.dt.t,kindparameter=NULL(),lenparameterkind=.lpk.t.1,component=.c.t.1,procptr=NULL(),special=NULL())
 !CHECK: .lpk.t.1, SAVE, TARGET: ObjectEntity type: INTEGER(1) shape: 0_8:0_8 init:[INTEGER(1)::8_1]
     type(t(*)), intent(in) :: x
   end subroutine
 end module