[gcc(refs/users/guojiufu/heads/personal-branch)] [Ada] Crash on compiling project with multiple subunits per file

[Jiu Fu Guo]

https://gcc.gnu.org/g:82bcb33bcf2e76c37188791a9c920541339e0ec9

commit 82bcb33bcf2e76c37188791a9c920541339e0ec9
Author: Justin Squirek <squirek@adacore.com>
Date:   Sat May 2 17:17:24 2020 -0400

    [Ada] Crash on compiling project with multiple subunits per file
    
    2020-06-19  Justin Squirek  <squirek@adacore.com>
    
    gcc/ada/
    
            * lib.adb (Check_Same_Extended_Unit): Add check to determine if
            the body for the subunits exist in the same file as their
            specifications.

Diff:
---
 gcc/ada/lib.adb | 41 +++++++++++++++++++++++++++++++++--------
 1 file changed, 33 insertions(+), 8 deletions(-)

diff --git a/gcc/ada/lib.adb b/gcc/ada/lib.adb
index fd0f16731be..806f939e361 100644
--- a/gcc/ada/lib.adb
+++ b/gcc/ada/lib.adb
@@ -362,6 +362,12 @@ package body Lib is
          --  Step 2: Check subunits. If a subunit is instantiated, follow the
          --  instantiation chain rather than the stub chain.
 
+         --  Note that we must handle the case where the subunit exists in the
+         --  same body as the main unit (which may happen when Naming gets
+         --  manually specified within a project file or through tools like
+         --  gprname). Otherwise, we will have an infinite loop jumping around
+         --  the same file.
+
          Unit1 := Unit (Cunit (Unum1));
          Unit2 := Unit (Cunit (Unum2));
          Inst1 := Instantiation (Sind1);
@@ -384,21 +390,35 @@ package body Lib is
                   Length_Of_Name (Unit_Name (Unum2))
                then
                   Sloc2 := Sloc (Corresponding_Stub (Unit2));
-                  Unum2 := Get_Source_Unit (Sloc2);
-                  goto Continue;
 
+                  if Unum2 /= Get_Source_Unit (Sloc2) then
+                     Unum2 := Get_Source_Unit (Sloc2);
+                     goto Continue;
+                  else
+                     null; --  Unum2 already designates the correct unit
+                  end if;
                else
                   Sloc1 := Sloc (Corresponding_Stub (Unit1));
-                  Unum1 := Get_Source_Unit (Sloc1);
-                  goto Continue;
+
+                  if Unum1 /= Get_Source_Unit (Sloc1) then
+                     Unum1 := Get_Source_Unit (Sloc1);
+                     goto Continue;
+                  else
+                     null; --  Unum1 already designates the correct unit
+                  end if;
                end if;
 
             --  Sloc1 in subunit, Sloc2 not
 
             else
                Sloc1 := Sloc (Corresponding_Stub (Unit1));
-               Unum1 := Get_Source_Unit (Sloc1);
-               goto Continue;
+
+               if Unum1 /= Get_Source_Unit (Sloc1) then
+                  Unum1 := Get_Source_Unit (Sloc1);
+                  goto Continue;
+               else
+                  null; --  Unum1 already designates the correct unit
+               end if;
             end if;
 
          --  Sloc2 in subunit, Sloc1 not
@@ -408,8 +428,13 @@ package body Lib is
            and then Inst2 = No_Location
          then
             Sloc2 := Sloc (Corresponding_Stub (Unit2));
-            Unum2 := Get_Source_Unit (Sloc2);
-            goto Continue;
+
+            if Unum2 /= Get_Source_Unit (Sloc2) then
+               Unum2 := Get_Source_Unit (Sloc2);
+               goto Continue;
+            else
+               null; --  Unum2 already designates the correct unit
+            end if;
          end if;
 
          --  Step 3: Check instances. The two locations may yield a common