diff --git a/flang/lib/Semantics/mod-file.cpp b/flang/lib/Semantics/mod-file.cpp
--- a/flang/lib/Semantics/mod-file.cpp
+++ b/flang/lib/Semantics/mod-file.cpp
@@ -319,6 +319,10 @@
     bindAttrs.set(Attr::BIND_C, true);
     attrs.set(Attr::BIND_C, false);
   }
+  bool isAbstract{attrs.test(Attr::ABSTRACT)};
+  if (isAbstract) {
+    attrs.set(Attr::ABSTRACT, false);
+  }
   Attrs prefixAttrs{subprogramPrefixAttrs & attrs};
   // emit any non-prefix attributes in an attribute statement
   attrs &= ~subprogramPrefixAttrs;
@@ -331,7 +335,7 @@
   bool isInterface{details.isInterface()};
   llvm::raw_ostream &os{isInterface ? decls_ : contains_};
   if (isInterface) {
-    os << "interface\n";
+    os << (isAbstract ? "abstract " : "") << "interface\n";
   }
   PutAttrs(os, prefixAttrs, std::nullopt, ""s, " "s);
   os << (details.isFunction() ? "function " : "subroutine ");
@@ -457,6 +461,11 @@
       }
     }
   }
+  // Sort most symbols by name: use of Symbol::ReplaceName ensures the source
+  // location of a symbol's name is the first "real" use.
+  std::sort(sorted.begin(), sorted.end(), [](SymbolRef x, SymbolRef y) {
+    return x->name().begin() < y->name().begin();
+  });
   sorted.insert(sorted.end(), namelist.begin(), namelist.end());
   for (const auto &pair : scope.commonBlocks()) {
     sorted.push_back(*pair.second);
diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -3085,11 +3085,14 @@
     symbol = &MakeSymbol(name, SubprogramDetails{});
   }
   symbol->set(subpFlag);
+  symbol->ReplaceName(name.source);
   PushScope(Scope::Kind::Subprogram, symbol);
   auto &details{symbol->get<SubprogramDetails>()};
   if (inInterfaceBlock()) {
     details.set_isInterface();
-    if (!isAbstract()) {
+    if (isAbstract()) {
+      symbol->attrs().set(Attr::ABSTRACT);
+    } else {
       MakeExternal(*symbol);
     }
     if (isGeneric()) {
diff --git a/flang/test/Semantics/modfile10.f90 b/flang/test/Semantics/modfile10.f90
--- a/flang/test/Semantics/modfile10.f90
+++ b/flang/test/Semantics/modfile10.f90
@@ -90,3 +90,40 @@
 !  subroutine test()
 !  end
 !end
+
+! Ensure the type is emitted before its use
+module m2
+  private s
+  type :: t
+  contains
+    procedure :: foo
+  end type
+  abstract interface
+    subroutine s(x)
+      import
+      type(t) :: x
+    end subroutine
+  end interface
+contains
+  subroutine foo(x)
+    class(t) :: x
+  end subroutine
+end module
+!Expect: m2.mod
+!module m2
+!  type::t
+!  contains
+!    procedure::foo
+!  end type
+!  private::s
+!  abstract interface
+!    subroutine s(x)
+!      import::t
+!      type(t)::x
+!    end
+!  end interface
+!contains
+!  subroutine foo(x)
+!    class(t)::x
+!  end
+!end
diff --git a/flang/test/Semantics/procinterface01.f90 b/flang/test/Semantics/procinterface01.f90
--- a/flang/test/Semantics/procinterface01.f90
+++ b/flang/test/Semantics/procinterface01.f90
@@ -5,7 +5,7 @@
 !DEF: /module1 Module
 module module1
  abstract interface
-  !DEF: /module1/abstract1 PUBLIC (Function) Subprogram REAL(4)
+  !DEF: /module1/abstract1 ABSTRACT, PUBLIC (Function) Subprogram REAL(4)
   !DEF: /module1/abstract1/x INTENT(IN) ObjectEntity REAL(4)
   real function abstract1(x)
    !REF: /module1/abstract1/x
diff --git a/flang/test/Semantics/symbol15.f90 b/flang/test/Semantics/symbol15.f90
--- a/flang/test/Semantics/symbol15.f90
+++ b/flang/test/Semantics/symbol15.f90
@@ -5,7 +5,7 @@
 module m
  implicit none
  abstract interface
-  !DEF: /m/iface PUBLIC (Subroutine) Subprogram
+  !DEF: /m/iface ABSTRACT, PUBLIC (Subroutine) Subprogram
   subroutine iface
   end subroutine
  end interface