This addresses PR ada/100486, which is the bootstrap failure of GCC 11 for 32-
bit Windows in the MSYS setup. The PR shows that we cannot rely on exception
propagation being operational during the bootstrap, at least on the 11 branch,
so fix this by removing the problematic raise statement.
Tested on x86-64/Linux, applied on the mainline and 11 branch.
2021-10-20 Arnaud Charlet <char...@adacore.com>
PR ada/100486
* sem_prag.adb (Check_Valid_Library_Unit_Pragma): Do not raise an
exception as part of the bootstrap.
--
Eric Botcazoucommit 035e7f25f8e01296da7dce327ef28ba15e1ccd8f
Author: Arnaud Charlet <char...@adacore.com>
Date: Mon Oct 18 03:35:44 2021 -0400
PR ada/100486 Avoid exception propagation during bootstrap
On some environments, we cannot rely on exception propagation being
operational during the bootstrap, as show by PR ada/100486 on windows
32bits mingw.
Fix this by removing the problematic raise statement.
[changelog]
* sem_prag.adb (Check_Valid_Library_Unit_Pragma): Do not raise an
exception as part of the bootstrap.
Change-Id: I52c541c93fe4f95a67cfc296b821d500bb90341b
TN: UA18-007
diff --git a/sem_prag.adb b/sem_prag.adb
index b3fa32ad5c..1e6397f87b 100644
--- a/sem_prag.adb
+++ b/sem_prag.adb
@@ -4144,8 +4144,10 @@ procedure Check_Valid_Library_Unit_Pragma;
-- than library level instantiations these can appear in contexts which
-- would normally be invalid (they only apply to the original template
-- and to library level instantiations), and they are simply ignored,
- -- which is implemented by rewriting them as null statements and raising
- -- exception to terminate analysis.
+ -- which is implemented by rewriting them as null statements and
+ -- optionally raising Pragma_Exit to terminate analysis. An exception
+ -- is not always raised to avoid exception propagation during the
+ -- bootstrap, so all callers should check whether N has been rewritten.
procedure Check_Variant (Variant : Node_Id; UU_Typ : Entity_Id);
-- Check an Unchecked_Union variant for lack of nested variants and
@@ -6652,8 +6654,14 @@ procedure Check_Valid_Library_Unit_Pragma is
Sindex := Source_Index (Current_Sem_Unit);
if Loc not in Source_First (Sindex) .. Source_Last (Sindex) then
+ -- We do not want to raise an exception here since this code
+ -- is part of the bootstrap path where we cannot rely on
+ -- exception proapgation working.
+ -- Instead the caller should check for N being rewritten as
+ -- a null statement.
+ -- This code triggers when compiling a-except.adb.
+
Rewrite (N, Make_Null_Statement (Loc));
- raise Pragma_Exit;
-- If before first declaration, the pragma applies to the
-- enclosing unit, and the name if present must be this name.
@@ -12719,6 +12727,13 @@ procedure Malformed_State_Error (State : Node_Id) is
Check_Ada_83_Warning;
Check_Valid_Library_Unit_Pragma;
+ -- If N was rewritten as a null statement there is nothing more
+ -- to do.
+
+ if Nkind (N) = N_Null_Statement then
+ return;
+ end if;
+
Lib_Entity := Find_Lib_Unit_Name;
-- A pragma that applies to a Ghost entity becomes Ghost for the
@@ -15967,6 +15982,13 @@ function Is_Acceptable_Dim3 (N : Node_Id) return Boolean is
Check_Ada_83_Warning;
Check_Valid_Library_Unit_Pragma;
+ -- If N was rewritten as a null statement there is nothing more
+ -- to do.
+
+ if Nkind (N) = N_Null_Statement then
+ return;
+ end if;
+
Cunit_Node := Cunit (Current_Sem_Unit);
Cunit_Ent := Cunit_Entity (Current_Sem_Unit);
@@ -19650,6 +19672,13 @@ procedure Skip_Spaces is
GNAT_Pragma;
Check_Valid_Library_Unit_Pragma;
+ -- If N was rewritten as a null statement there is nothing more
+ -- to do.
+
+ if Nkind (N) = N_Null_Statement then
+ return;
+ end if;
+
-- Must appear for a spec or generic spec
if Nkind (Unit (Cunit (Current_Sem_Unit))) not in
@@ -21436,6 +21465,13 @@ procedure Propagate_Part_Of (Pack_Id : Entity_Id) is
Check_Ada_83_Warning;
Check_Valid_Library_Unit_Pragma;
+ -- If N was rewritten as a null statement there is nothing more
+ -- to do.
+
+ if Nkind (N) = N_Null_Statement then
+ return;
+ end if;
+
Ent := Find_Lib_Unit_Name;
-- A pragma that applies to a Ghost entity becomes Ghost for the
@@ -22072,8 +22108,15 @@ procedure Check_Arg (Arg : Node_Id) is
if Is_Wrapper_Package (Current_Scope) then
return;
- else
- Check_Valid_Library_Unit_Pragma;
+ end if;
+
+ Check_Valid_Library_Unit_Pragma;
+
+ -- If N was rewritten as a null statement there is nothing more
+ -- to do.
+
+ if Nkind (N) = N_Null_Statement then
+ return;
end if;
Ent := Find_Lib_Unit_Name;
@@ -22612,6 +22655,13 @@ procedure Check_Arg (Arg : Node_Id) is
Check_Ada_83_Warning;
Check_Valid_Library_Unit_Pragma;
+ -- If N was rewritten as a null statement there is nothing more
+ -- to do.
+
+ if Nkind (N) = N_Null_Statement then
+ return;
+ end if;
+
Cunit_Node := Cunit (Current_Sem_Unit);
K := Nkind (Unit (Cunit_Node));
Cunit_Ent := Cunit_Entity (Current_Sem_Unit);
@@ -22651,6 +22701,13 @@ procedure Check_Arg (Arg : Node_Id) is
Check_Ada_83_Warning;
Check_Valid_Library_Unit_Pragma;
+ -- If N was rewritten as a null statement there is nothing more
+ -- to do.
+
+ if Nkind (N) = N_Null_Statement then
+ return;
+ end if;
+
Cunit_Node := Cunit (Current_Sem_Unit);
Cunit_Ent := Cunit_Entity (Current_Sem_Unit);
@@ -22847,6 +22904,13 @@ procedure Check_Arg (Arg : Node_Id) is
Check_Ada_83_Warning;
Check_Valid_Library_Unit_Pragma;
+ -- If N was rewritten as a null statement there is nothing more
+ -- to do.
+
+ if Nkind (N) = N_Null_Statement then
+ return;
+ end if;
+
Cunit_Node := Cunit (Current_Sem_Unit);
Cunit_Ent := Cunit_Entity (Current_Sem_Unit);
