2017-09-29 Bob Duff <duff@adacore.com>

	* exp_ch6.adb (Expand_Call_Helper): Replace with code more similar to
	what we had before.
	(Make_Build_In_Place_Call_In_Object_Declaration): Back out previous
	change. Set the Etype in the class-wide case. This fixes a regression
	in the libadalang test suite.

2017-09-29  Joel Brobecker  <brobecker@adacore.com>

	* doc/gnat_ugn/building_executable_programs_with_gnat.rst,
	doc/gnat_ugn/the_gnat_compilation_model.rst: Avoid use of single colon
	in comment markup.
	* gnat_ugn.texi: Regenerate.

2017-09-29  Justin Squirek  <squirek@adacore.com>

	* ali-util.adb, comperr.adb, cprint.adb, errout.adb, fmap.adb,
	fname-sf.adb, frontend.adb, lib-xref-spark_specific.adb, gnat1drv.adb,
	gnatls.adb, lib.adb, lib-load.adb, lib-writ.adb, prepcomp.adb,
	sinput-d.adb, sinput-l.adb, sprint.adb, targparm.adb: Update comparison
	for checking source file status and error message and/or call to
	Read_Source_File.
	* libgnat/s-os_lib.ads: Add new potential value constant for
	uninitialized file descriptors.
	* osint.adb, osint.ads (Read_Source_File): Add extra parameter to
	return result of IO to encompass a read access failure in addition to a
	file-not-found error.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@253294 138bc75d-0d04-0410-961f-82ee72b054a4

25 files changed, 159 insertions, 71 deletions

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index c71ad27325b..4e931f9a6ff 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,5 +1,34 @@
 2017-09-29  Bob Duff  <duff@adacore.com>
 
+	* exp_ch6.adb (Expand_Call_Helper): Replace with code more similar to
+	what we had before.
+	(Make_Build_In_Place_Call_In_Object_Declaration): Back out previous
+	change. Set the Etype in the class-wide case. This fixes a regression
+	in the libadalang test suite.
+
+2017-09-29  Joel Brobecker  <brobecker@adacore.com>
+
+	* doc/gnat_ugn/building_executable_programs_with_gnat.rst,
+	doc/gnat_ugn/the_gnat_compilation_model.rst: Avoid use of single colon
+	in comment markup.
+	* gnat_ugn.texi: Regenerate.
+
+2017-09-29  Justin Squirek  <squirek@adacore.com>
+
+	* ali-util.adb, comperr.adb, cprint.adb, errout.adb, fmap.adb,
+	fname-sf.adb, frontend.adb, lib-xref-spark_specific.adb, gnat1drv.adb,
+	gnatls.adb, lib.adb, lib-load.adb, lib-writ.adb, prepcomp.adb,
+	sinput-d.adb, sinput-l.adb, sprint.adb, targparm.adb: Update comparison
+	for checking source file status and error message and/or call to
+	Read_Source_File.
+	* libgnat/s-os_lib.ads: Add new potential value constant for
+	uninitialized file descriptors.
+	* osint.adb, osint.ads (Read_Source_File): Add extra parameter to
+	return result of IO to encompass a read access failure in addition to a
+	file-not-found error.
+
+2017-09-29  Bob Duff  <duff@adacore.com>
+
 	* exp_ch6.adb (Expand_Call_Helper): Handle case of build-in-place
 	functions returning nonlimited types. Allow for qualified expressions
 	and type conversions.
diff --git a/gcc/ada/ali-util.adb b/gcc/ada/ali-util.adb
index 40e2276fb65..ea4e8567f94 100644
--- a/gcc/ada/ali-util.adb
+++ b/gcc/ada/ali-util.adb
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 1992-2014, Free Software Foundation, Inc.         --
+--          Copyright (C) 1992-2017, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -148,7 +148,7 @@ package body ALI.Util is
 
       Source_Index := Sinput.C.Load_File (Get_Name_String (Full_Name));
 
-      if Source_Index = No_Source_File then
+      if Source_Index <= No_Source_File then
          return Checksum_Error;
       end if;
 
diff --git a/gcc/ada/comperr.adb b/gcc/ada/comperr.adb
index 1b5aa3ebfe5..e76081c2ed0 100644
--- a/gcc/ada/comperr.adb
+++ b/gcc/ada/comperr.adb
@@ -253,6 +253,7 @@ package body Comperr is
          --  we use the contents of this file at this point.
 
          declare
+            FD  : File_Descriptor;
             Lo  : Source_Ptr;
             Hi  : Source_Ptr;
             Src : Source_Buffer_Ptr;
@@ -261,7 +262,7 @@ package body Comperr is
             Namet.Unlock;
             Name_Buffer (1 .. 12) := "gnat_bug.box";
             Name_Len := 12;
-            Read_Source_File (Name_Enter, 0, Hi, Src);
+            Read_Source_File (Name_Enter, 0, Hi, Src, FD);
 
             --  If we get a Src file, we use it
 
@@ -457,7 +458,7 @@ package body Comperr is
       --  If parsing was not successful, no Main_Unit is available, so return
       --  immediately.
 
-      if Main_Source_File = No_Source_File then
+      if Main_Source_File <= No_Source_File then
          return;
       end if;
 
diff --git a/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst b/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst
index ec152f27de3..046fe35a825 100644
--- a/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst
+++ b/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst
@@ -559,7 +559,7 @@ You may specify any of the following switches to ``gnatmake``:
   -f, it is equivalent to calling the compiler directly. Note that using
   -u with a project file and no main has a special meaning.
 
-.. --Comment:
+.. --Comment
   (See :ref:`Project_Files_and_Main_Subprograms`.)
 
 
diff --git a/gcc/ada/doc/gnat_ugn/the_gnat_compilation_model.rst b/gcc/ada/doc/gnat_ugn/the_gnat_compilation_model.rst
index 8c3b074ec8d..248bf8ef97f 100644
--- a/gcc/ada/doc/gnat_ugn/the_gnat_compilation_model.rst
+++ b/gcc/ada/doc/gnat_ugn/the_gnat_compilation_model.rst
@@ -1569,7 +1569,7 @@ depend on a file that no longer exists. Such tools include
 If you are using project file, a separate mechanism is provided using
 project attributes.
 
-.. --Comment:
+.. --Comment
    See :ref:`Specifying_Configuration_Pragmas` for more details.
 
 
diff --git a/gcc/ada/errout.adb b/gcc/ada/errout.adb
index ce99fd842d0..a402c684101 100644
--- a/gcc/ada/errout.adb
+++ b/gcc/ada/errout.adb
@@ -1813,7 +1813,7 @@ package body Errout is
          --  the Main_Source line is unknown (this happens in error situations,
          --  e.g. when integrated preprocessing fails).
 
-         if Main_Source_File /= No_Source_File then
+         if Main_Source_File > No_Source_File then
             Write_Str (" ");
             Write_Int (Num_Source_Lines (Main_Source_File));
 
@@ -1938,7 +1938,7 @@ package body Errout is
       --  Source_Reference. This ensures outputting the proper name of
       --  the source file in this situation.
 
-      if Main_Source_File = No_Source_File
+      if Main_Source_File <= No_Source_File
         or else Num_SRef_Pragmas (Main_Source_File) /= 0
       then
          Current_Error_Source_File := No_Source_File;
@@ -2045,7 +2045,7 @@ package body Errout is
 
                   --  Only write the header if Sfile is known
 
-                  if Sfile /= No_Source_File then
+                  if Sfile > No_Source_File then
                      Write_Header (Sfile);
                      Write_Eol;
                   end if;
@@ -2066,7 +2066,7 @@ package body Errout is
                   --  Only output the listing if Sfile is known, to avoid
                   --  crashing the compiler.
 
-                  if Sfile /= No_Source_File then
+                  if Sfile > No_Source_File then
                      for N in 1 .. Last_Source_Line (Sfile) loop
                         while E /= No_Error_Msg
                           and then Errors.Table (E).Deleted
@@ -2141,7 +2141,7 @@ package body Errout is
 
          --  Output the header only when Main_Source_File is known
 
-         if Main_Source_File /= No_Source_File then
+         if Main_Source_File > No_Source_File then
             Write_Header (Main_Source_File);
          end if;
 
diff --git a/gcc/ada/exp_ch6.adb b/gcc/ada/exp_ch6.adb
index 5fcd1f587cd..715e74cfebe 100644
--- a/gcc/ada/exp_ch6.adb
+++ b/gcc/ada/exp_ch6.adb
@@ -4330,11 +4330,19 @@ package body Exp_Ch6 is
       --  result from the secondary stack.
 
       if Needs_Finalization (Etype (Subp)) then
+         if not Is_Build_In_Place_Function_Call (Call_Node)
+           and then
+             (No (First_Formal (Subp))
+                or else
+                  not Is_Concurrent_Record_Type (Etype (First_Formal (Subp))))
+         then
+            Expand_Ctrl_Function_Call (Call_Node);
+
          --  Build-in-place function calls which appear in anonymous contexts
          --  need a transient scope to ensure the proper finalization of the
          --  intermediate result after its use.
 
-         if Is_Build_In_Place_Function_Call (Call_Node)
+         elsif Is_Build_In_Place_Function_Call (Call_Node)
            and then
              Nkind_In (Parent (Unqual_Conv (Call_Node)),
                        N_Attribute_Reference,
@@ -4346,14 +4354,6 @@ package body Exp_Ch6 is
                        N_Slice)
          then
             Establish_Transient_Scope (Call_Node, Sec_Stack => True);
-
-         elsif not Is_Build_In_Place_Function_Call (Call_Node)
-           and then
-             (No (First_Formal (Subp))
-                or else
-                  not Is_Concurrent_Record_Type (Etype (First_Formal (Subp))))
-         then
-            Expand_Ctrl_Function_Call (Call_Node);
          end if;
       end if;
    end Expand_Call_Helper;
@@ -6393,9 +6393,9 @@ package body Exp_Ch6 is
          end if;
       end if;
 
-      --  For the case of a simple return that does not come from an extended
-      --  return, in the case of build-in-place, we rewrite "return
-      --  <expression>;" to be:
+      --  For the case of a simple return that does not come from an
+      --  extended return, in the case of build-in-place, we rewrite
+      --  "return <expression>;" to be:
 
       --    return _anon_ : <return_subtype> := <expression>
 
@@ -8518,6 +8518,18 @@ package body Exp_Ch6 is
               (Obj_Decl, Original_Node (Obj_Decl));
          end if;
       end;
+
+      --  If the object entity has a class-wide Etype, then we need to change
+      --  it to the result subtype of the function call, because otherwise the
+      --  object will be class-wide without an explicit initialization and
+      --  won't be allocated properly by the back end. It seems unclean to make
+      --  such a revision to the type at this point, and we should try to
+      --  improve this treatment when build-in-place functions with class-wide
+      --  results are implemented. ???
+
+      if Is_Class_Wide_Type (Etype (Defining_Identifier (Obj_Decl))) then
+         Set_Etype (Defining_Identifier (Obj_Decl), Result_Subt);
+      end if;
    end Make_Build_In_Place_Call_In_Object_Declaration;
 
    -------------------------------------------------
diff --git a/gcc/ada/fmap.adb b/gcc/ada/fmap.adb
index d517c2a4ddc..4345dfa8005 100644
--- a/gcc/ada/fmap.adb
+++ b/gcc/ada/fmap.adb
@@ -175,6 +175,7 @@ package body Fmap is
    ----------------
 
    procedure Initialize (File_Name : String) is
+      FD  : File_Descriptor;
       Src : Source_Buffer_Ptr;
       Hi  : Source_Ptr;
 
@@ -297,10 +298,14 @@ package body Fmap is
 
    begin
       Empty_Tables;
-      Read_Source_File (Name_Enter (File_Name), 1, Hi, Src, Config);
+      Read_Source_File (Name_Enter (File_Name), 1, Hi, Src, FD, Config);
 
       if Null_Source_Buffer_Ptr (Src) then
-         Write_Str ("warning: could not read mapping file """);
+         if FD = Null_FD then
+            Write_Str ("warning: could not locate mapping file """);
+         else
+            Write_Str ("warning: no read access for mapping file """);
+         end if;
          Write_Str (File_Name);
          Write_Line ("""");
          No_Mapping_File := True;
diff --git a/gcc/ada/fname-sf.adb b/gcc/ada/fname-sf.adb
index be115bca0b7..53cc9d19f1c 100644
--- a/gcc/ada/fname-sf.adb
+++ b/gcc/ada/fname-sf.adb
@@ -23,12 +23,13 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
-with Casing;   use Casing;
-with Fname;    use Fname;
-with Fname.UF; use Fname.UF;
-with SFN_Scan; use SFN_Scan;
-with Osint;    use Osint;
-with Types;    use Types;
+with Casing;        use Casing;
+with Fname;         use Fname;
+with Fname.UF;      use Fname.UF;
+with SFN_Scan;      use SFN_Scan;
+with Osint;         use Osint;
+with Types;         use Types;
+with System.OS_Lib; use System.OS_Lib;
 
 with Unchecked_Conversion;
 
@@ -61,11 +62,12 @@ package body Fname.SF is
    -----------------------------------
 
    procedure Read_Source_File_Name_Pragmas is
+      FD  : File_Descriptor;
       Src : Source_Buffer_Ptr;
       Hi  : Source_Ptr;
 
    begin
-      Read_Source_File (Name_Enter ("gnat.adc"), 1, Hi, Src);
+      Read_Source_File (Name_Enter ("gnat.adc"), 1, Hi, Src, FD);
 
       if not Null_Source_Buffer_Ptr (Src) then
          --  We need to strip off the trailing EOF that was added by
diff --git a/gcc/ada/frontend.adb b/gcc/ada/frontend.adb
index c55085856c0..bb28eae1192 100644
--- a/gcc/ada/frontend.adb
+++ b/gcc/ada/frontend.adb
@@ -126,7 +126,7 @@ begin
 
    --  Return immediately if the main source could not be found
 
-   if Sinput.Main_Source_File = No_Source_File then
+   if Sinput.Main_Source_File <= No_Source_File then
       return;
    end if;
 
@@ -167,7 +167,7 @@ begin
 
          --  Case of gnat.adc file present
 
-         if Source_gnat_adc /= No_Source_File then
+         if Source_gnat_adc > No_Source_File then
             --  Parse the gnat.adc file for configuration pragmas
 
             Initialize_Scanner (No_Unit, Source_gnat_adc);
@@ -213,7 +213,7 @@ begin
 
                   Source_Config_File := Load_Config_File (Config_Name);
 
-                  if Source_Config_File = No_Source_File then
+                  if Source_Config_File <= No_Source_File then
                      Osint.Fail
                        ("cannot find configuration pragmas file "
                         & Config_File_Names (Index).all);
diff --git a/gcc/ada/gnat1drv.adb b/gcc/ada/gnat1drv.adb
index 0e3bc27becb..882631f9bee 100644
--- a/gcc/ada/gnat1drv.adb
+++ b/gcc/ada/gnat1drv.adb
@@ -852,7 +852,7 @@ procedure Gnat1drv is
          --  pragma, to be used this way and to cause the body file to be
          --  ignored in this context).
 
-         if Src_Ind /= No_Source_File
+         if Src_Ind > No_Source_File
            and then Source_File_Is_Body (Src_Ind)
          then
             Errout.Finalize (Last_Call => False);
@@ -1065,6 +1065,11 @@ begin
                  ("fatal error, run-time library not installed correctly");
                Write_Line ("cannot locate file system.ads");
                raise Unrecoverable_Error;
+            elsif S = No_Access_To_Source_File then
+               Write_Line
+                 ("fatal error, run-time library not installed correctly");
+               Write_Line ("no read access for file system.ads");
+               raise Unrecoverable_Error;
 
             --  Read system.ads successfully, remember its source index
 
@@ -1141,7 +1146,7 @@ begin
 
       --  Exit with errors if the main source could not be parsed
 
-      if Sinput.Main_Source_File = No_Source_File then
+      if Sinput.Main_Source_File <= No_Source_File then
          Errout.Finalize (Last_Call => True);
          Errout.Output_Messages;
          Exit_Program (E_Errors);
diff --git a/gcc/ada/gnat_ugn.texi b/gcc/ada/gnat_ugn.texi
index 5fdb2724ba1..49abd462265 100644
--- a/gcc/ada/gnat_ugn.texi
+++ b/gcc/ada/gnat_ugn.texi
@@ -3193,7 +3193,7 @@ depend on a file that no longer exists. Such tools include
 If you are using project file, a separate mechanism is provided using
 project attributes.
 
-@c --Comment:
+@c --Comment
 @c See :ref:`Specifying_Configuration_Pragmas` for more details.
 
 @node Generating Object Files,Source Dependencies,Configuration Pragmas,The GNAT Compilation Model
@@ -7925,7 +7925,7 @@ Unique. Recompile at most the main files. It implies -c. Combined with
 -u with a project file and no main has a special meaning.
 @end table
 
-@c --Comment:
+@c --Comment
 @c (See :ref:`Project_Files_and_Main_Subprograms`.)
 
 @geindex -U (gnatmake)
diff --git a/gcc/ada/gnatls.adb b/gcc/ada/gnatls.adb
index 925ae2c7836..f45305f9e81 100644
--- a/gcc/ada/gnatls.adb
+++ b/gcc/ada/gnatls.adb
@@ -2097,6 +2097,7 @@ begin
 
    if RTS_Specified = null then
       declare
+         FD   : File_Descriptor;
          Text : Source_Buffer_Ptr;
          Hi   : Source_Ptr;
 
@@ -2104,7 +2105,7 @@ begin
          Name_Buffer (1 .. 10) := "system.ads";
          Name_Len := 10;
 
-         Read_Source_File (Name_Find, Lo => 0, Hi => Hi, Src => Text);
+         Read_Source_File (Name_Find, 0, Hi, Text, FD);
 
          if Null_Source_Buffer_Ptr (Text) then
             No_Runtime := True;
diff --git a/gcc/ada/lib-load.adb b/gcc/ada/lib-load.adb
index f509721c398..1419422887f 100644
--- a/gcc/ada/lib-load.adb
+++ b/gcc/ada/lib-load.adb
@@ -122,7 +122,7 @@ package body Lib.Load is
 
       --  No change if we did not find the spec
 
-      if X = No_Source_File then
+      if X <= No_Source_File then
          return;
       end if;
 
@@ -326,7 +326,7 @@ package body Lib.Load is
          Main_Source_File := Load_Source_File (Fname);
          Current_Error_Source_File := Main_Source_File;
 
-         if Main_Source_File /= No_Source_File then
+         if Main_Source_File > No_Source_File then
             Version := Source_Checksum (Main_Source_File);
          else
             --  To avoid emitting a source location (since there is no file),
@@ -334,7 +334,13 @@ package body Lib.Load is
             --  in errout.adb.
 
             Set_Standard_Error;
-            Write_Str ("file """ & Get_Name_String (Fname) & """ not found");
+            if Main_Source_File = No_Access_To_Source_File then
+               Write_Str ("no read access for file """
+                          & Get_Name_String (Fname) & """");
+            else
+               Write_Str ("file """
+                          & Get_Name_String (Fname) & """ not found");
+            end if;
             Write_Eol;
             Set_Standard_Output;
          end if;
@@ -716,7 +722,7 @@ package body Lib.Load is
 
          --  File was found
 
-         if Src_Ind /= No_Source_File then
+         if Src_Ind > No_Source_File then
             Units.Table (Unum) :=
               (Cunit             => Empty,
                Cunit_Entity      => Empty,
@@ -824,7 +830,11 @@ package body Lib.Load is
 
          else
             if Debug_Flag_L then
-               Write_Str ("  file was not found, load failed");
+               if Src_Ind = No_Access_To_Source_File then
+                  Write_Str ("  no read access to file, load failed");
+               else
+                  Write_Str ("  file was not found, load failed");
+               end if;
                Write_Eol;
             end if;
 
@@ -857,7 +867,11 @@ package body Lib.Load is
 
                else
                   Error_Msg_File_1 := Fname;
-                  Error_Msg ("file{ not found", Load_Msg_Sloc);
+                  if Src_Ind = No_Access_To_Source_File then
+                     Error_Msg ("no read access to file{", Load_Msg_Sloc);
+                  else
+                     Error_Msg ("file{ not found", Load_Msg_Sloc);
+                  end if;
                end if;
 
                Write_Dependency_Chain;
@@ -983,7 +997,7 @@ package body Lib.Load is
       Unum  : constant Unit_Number_Type := Get_Cunit_Unit_Number (U);
       Fnum  : constant Unit_Number_Type := Get_Cunit_Unit_Number (From);
    begin
-      if Source_Index (Fnum) /= No_Source_File then
+      if Source_Index (Fnum) > No_Source_File then
          Units.Table (Unum).Version :=
            Units.Table (Unum).Version
              xor
diff --git a/gcc/ada/lib-writ.adb b/gcc/ada/lib-writ.adb
index 8c36957228c..d263b05dc1c 100644
--- a/gcc/ada/lib-writ.adb
+++ b/gcc/ada/lib-writ.adb
@@ -1464,7 +1464,7 @@ package body Lib.Writ is
 
             --  Normal case of a unit entry with a source index
 
-            if Sind /= No_Source_File then
+            if Sind > No_Source_File then
                Fname := File_Name (Sind);
 
                --  Ensure that on platforms where the file names are not case
diff --git a/gcc/ada/lib-xref-spark_specific.adb b/gcc/ada/lib-xref-spark_specific.adb
index b6ddd93783c..4d221749907 100644
--- a/gcc/ada/lib-xref-spark_specific.adb
+++ b/gcc/ada/lib-xref-spark_specific.adb
@@ -249,7 +249,7 @@ package body SPARK_Specific is
       --  Source file could be inexistant as a result of an error, if option
       --  gnatQ is used.
 
-      if File = No_Source_File then
+      if File <= No_Source_File then
          return;
       end if;
 
diff --git a/gcc/ada/lib.adb b/gcc/ada/lib.adb
index 16c8afc9ccb..9373f9519e7 100644
--- a/gcc/ada/lib.adb
+++ b/gcc/ada/lib.adb
@@ -626,7 +626,7 @@ package body Lib is
             Source_File := Get_Source_File_Index (S);
 
             if Unwind_Instances then
-               while Template (Source_File) /= No_Source_File loop
+               while Template (Source_File) > No_Source_File loop
                   Source_File := Template (Source_File);
                end loop;
             end if;
diff --git a/gcc/ada/libgnat/s-os_lib.ads b/gcc/ada/libgnat/s-os_lib.ads
index 5fba00aad64..813ed1a9730 100644
--- a/gcc/ada/libgnat/s-os_lib.ads
+++ b/gcc/ada/libgnat/s-os_lib.ads
@@ -191,6 +191,9 @@ package System.OS_Lib is
    Invalid_FD : constant File_Descriptor := -1;
    --  File descriptor returned when error in opening/creating file
 
+   Null_FD : constant File_Descriptor := -2;
+   --  Uninitialized file descriptor
+
    procedure Close (FD : File_Descriptor; Status : out Boolean);
    --  Close file referenced by FD. Status is False if the underlying service
    --  failed. Reasons for failure include: disk full, disk quotas exceeded
diff --git a/gcc/ada/osint.adb b/gcc/ada/osint.adb
index 105e866c373..781db47d0af 100644
--- a/gcc/ada/osint.adb
+++ b/gcc/ada/osint.adb
@@ -2565,9 +2565,10 @@ package body Osint is
       Lo  : Source_Ptr;
       Hi  : out Source_Ptr;
       Src : out Source_Buffer_Ptr;
+      FD  : out File_Descriptor;
       T   : File_Type := Source)
    is
-      Source_File_FD : File_Descriptor;
+      --  Source_File_FD : File_Descriptor;
       --  The file descriptor for the current source file. A negative value
       --  indicates failure to open the specified source file.
 
@@ -2594,6 +2595,7 @@ package body Osint is
             Fail ("Cannot find: " & Name_Buffer (1 .. Name_Len));
          end if;
 
+         FD  := Null_FD;
          Src := null;
          Hi  := No_Location;
          return;
@@ -2607,9 +2609,9 @@ package body Osint is
       --  DOS or Unix mode files, and there is no point in wasting time on
       --  text translation when it is not required.
 
-      Source_File_FD := Open_Read (Name_Buffer'Address, Binary);
+      FD := Open_Read (Name_Buffer'Address, Binary);
 
-      if Source_File_FD = Invalid_FD then
+      if FD = Invalid_FD then
          Src := null;
          Hi  := No_Location;
          return;
@@ -2645,7 +2647,7 @@ package body Osint is
 
       --  Prepare to read data from the file
 
-      Len := Integer (File_Length (Source_File_FD));
+      Len := Integer (File_Length (FD));
 
       --  Set Hi so that length is one more than the physical length,
       --  allowing for the extra EOF character at the end of the buffer
@@ -2665,7 +2667,7 @@ package body Osint is
 
          Hi := Lo;
          loop
-            Actual_Len := Read (Source_File_FD, Var_Ptr (Hi)'Address, Len);
+            Actual_Len := Read (FD, Var_Ptr (Hi)'Address, Len);
             Hi := Hi + Source_Ptr (Actual_Len);
             exit when Actual_Len = Len or else Actual_Len <= 0;
          end loop;
@@ -2676,7 +2678,7 @@ package body Osint is
 
       --  Read is complete, get time stamp and close file and we are done
 
-      Close (Source_File_FD, Status);
+      Close (FD, Status);
 
       --  The status should never be False. But, if it is, what can we do?
       --  So, we don't test it.
diff --git a/gcc/ada/osint.ads b/gcc/ada/osint.ads
index 2805bfe62ad..4d6a4a4d8cd 100644
--- a/gcc/ada/osint.ads
+++ b/gcc/ada/osint.ads
@@ -401,6 +401,7 @@ package Osint is
       Lo  : Source_Ptr;
       Hi  : out Source_Ptr;
       Src : out Source_Buffer_Ptr;
+      FD  : out File_Descriptor;
       T   : File_Type := Source);
    --  Allocates a Source_Buffer of appropriate length and then reads the
    --  entire contents of the source file N into the buffer. The address of
diff --git a/gcc/ada/prepcomp.adb b/gcc/ada/prepcomp.adb
index cffb0cef991..7c56130c113 100644
--- a/gcc/ada/prepcomp.adb
+++ b/gcc/ada/prepcomp.adb
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2003-2016, Free Software Foundation, Inc.         --
+--          Copyright (C) 2003-2017, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -637,7 +637,7 @@ package body Prepcomp is
             T           : constant Nat               := Total_Errors_Detected;
 
          begin
-            if Deffile = No_Source_File then
+            if Deffile <= No_Source_File then
                Fail ("definition file """
                      & Get_Name_String (N)
                      & """ not found");
diff --git a/gcc/ada/sinput-d.adb b/gcc/ada/sinput-d.adb
index c9c128b8bbf..f8c4cb0ce14 100644
--- a/gcc/ada/sinput-d.adb
+++ b/gcc/ada/sinput-d.adb
@@ -23,10 +23,11 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
-with Debug;   use Debug;
-with Osint;   use Osint;
-with Osint.C; use Osint.C;
-with Output;  use Output;
+with Debug;         use Debug;
+with Osint;         use Osint;
+with Osint.C;       use Osint.C;
+with Output;        use Output;
+with System.OS_Lib; use System.OS_Lib;
 
 package body Sinput.D is
 
@@ -38,6 +39,7 @@ package body Sinput.D is
    ------------------------
 
    procedure Close_Debug_Source is
+      FD   : File_Descriptor;
       SFR  : Source_File_Record renames Source_File.Table (Dfile);
       Src  : Source_Buffer_Ptr;
    begin
@@ -48,7 +50,7 @@ package body Sinput.D is
       --  subsequent access.
 
       Read_Source_File
-        (SFR.Full_Debug_Name, SFR.Source_First, SFR.Source_Last, Src);
+        (SFR.Full_Debug_Name, SFR.Source_First, SFR.Source_Last, Src, FD);
       SFR.Source_Text := Src;
       pragma Assert (SFR.Source_Text'First = SFR.Source_First);
       pragma Assert (SFR.Source_Text'Last = SFR.Source_Last);
diff --git a/gcc/ada/sinput-l.adb b/gcc/ada/sinput-l.adb
index 360e7117e45..48061238659 100644
--- a/gcc/ada/sinput-l.adb
+++ b/gcc/ada/sinput-l.adb
@@ -354,6 +354,7 @@ package body Sinput.L is
      (N : File_Name_Type;
       T : Osint.File_Type) return Source_File_Index
    is
+      FD  : File_Descriptor;
       Src : Source_Buffer_Ptr;
       X   : Source_File_Index;
       Lo  : Source_Ptr;
@@ -411,12 +412,16 @@ package body Sinput.L is
                   Source_Align) * Source_Align;
       end if;
 
-      Osint.Read_Source_File (N, Lo, Hi, Src, T);
+      Osint.Read_Source_File (N, Lo, Hi, Src, FD, T);
 
       if Null_Source_Buffer_Ptr (Src) then
          Source_File.Decrement_Last;
-         return No_Source_File;
 
+         if FD = Null_FD then
+            return No_Source_File;
+         else
+            return No_Access_To_Source_File;
+         end if;
       else
          if Debug_Flag_L then
             Write_Eol;
diff --git a/gcc/ada/sprint.adb b/gcc/ada/sprint.adb
index 6e293109379..0052409b552 100644
--- a/gcc/ada/sprint.adb
+++ b/gcc/ada/sprint.adb
@@ -3752,7 +3752,7 @@ package body Sprint is
       --  Ignore if there is no current source file, or we're not in dump
       --  source text mode, or if in freeze actions.
 
-      if Current_Source_File /= No_Source_File
+      if Current_Source_File > No_Source_File
         and then Dump_Source_Text
         and then Freeze_Indent = 0
       then
diff --git a/gcc/ada/targparm.adb b/gcc/ada/targparm.adb
index 4855db50b15..725bb4c2867 100644
--- a/gcc/ada/targparm.adb
+++ b/gcc/ada/targparm.adb
@@ -23,10 +23,11 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
-with Csets;    use Csets;
+with Csets;         use Csets;
 with Opt;
-with Osint;    use Osint;
-with Output;   use Output;
+with Osint;         use Osint;
+with Output;        use Output;
+with System.OS_Lib; use System.OS_Lib;
 
 package body Targparm is
    use ASCII;
@@ -156,6 +157,7 @@ package body Targparm is
       Set_NUA : Set_NUA_Type := null;
       Set_NUP : Set_NUP_Type := null)
    is
+      FD   : File_Descriptor;
       Text : Source_Buffer_Ptr;
       Hi   : Source_Ptr;
 
@@ -167,11 +169,15 @@ package body Targparm is
       Name_Buffer (1 .. 10) := "system.ads";
       Name_Len := 10;
 
-      Read_Source_File (Name_Find, Lo => 0, Hi => Hi, Src => Text);
+      Read_Source_File (Name_Find, 0, Hi, Text, FD);
 
       if Null_Source_Buffer_Ptr (Text) then
          Write_Line ("fatal error, run-time library not installed correctly");
-         Write_Line ("cannot locate file system.ads");
+         if FD = Null_FD then
+            Write_Line ("cannot locate file system.ads");
+         else
+            Write_Line ("no read access for file system.ads");
+         end if;
          raise Unrecoverable_Error;
       end if;