This patch inhibits the generation of exception push/pop nodes if
restriction No_Exception_Handlers is active (when they are always
useless), or in CodePeer mode (where they are never needed and can
intefere with the analysis).
The following program
1. pragma Restrictions (No_Exception_Propagation);
2. pragma Restrictions (No_Exception_Handlers);
3. function NoPush (X : Integer) return Integer is
4. begin
5. return 10 / X;
6. end;
should generate the following -gnatG output:
Source recreated from tree for Nopush (body)
pragma restrictions (no_exception_propagation);
pragma restrictions (no_exception_handlers);
function nopush (x : integer) return integer is
begin
[constraint_error when
x = 0
"divide by zero"]
return integer(10 / x);
end nopush;
Tested on x86_64-pc-linux-gnu, committed on trunk
2011-11-04 Robert Dewar <de...@adacore.com>
* exp_ch11.adb (Generate_Push_Pop): Inhibit push/pop nodes in
CodePeer mode or if restriction No_Exception_Handlers is present.
* exp_ch6.adb (Expand_N_Subprogram_Body): (Inhibit push/pop
nodes in CodePeer mode or if restriction No_Exception_Handlers
is present.
Index: exp_ch11.adb
===================================================================
--- exp_ch11.adb (revision 180934)
+++ exp_ch11.adb (working copy)
@@ -334,7 +334,7 @@
-- raise statements into gotos, e.g. all N_Raise_xxx_Error nodes are
-- left unchanged and passed to the back end.
- -- Instead, the front end generates two nodes
+ -- Instead, the front end generates three nodes
-- N_Push_Constraint_Error_Label
-- N_Push_Program_Error_Label
@@ -356,6 +356,10 @@
-- field in the Push node will be empty signifying that for this region
-- of code, no optimization is possible.
+ -- These Push/Pop nodes are inhibited if No_Exception_Handlers is set
+ -- since they are useless in this case, and in CodePeer mode, where
+ -- they serve no purpose and can intefere with the analysis.
+
-- The back end must maintain three stacks, one for each exception case,
-- the Push node pushes an entry onto the corresponding stack, and Pop
-- node pops off the entry. Then instead of calling Rcheck_nn, if the
@@ -503,6 +507,12 @@
procedure Generate_Push_Pop (H : Node_Id) is
begin
+ if Restriction_Active (No_Exception_Handlers)
+ or else CodePeer_Mode
+ then
+ return;
+ end if;
+
if Exc_Locally_Handled then
return;
else
Index: exp_ch6.adb
===================================================================
--- exp_ch6.adb (revision 180934)
+++ exp_ch6.adb (working copy)
@@ -5679,10 +5679,14 @@
end if;
-- If local-exception-to-goto optimization active, insert dummy push
- -- statements at start, and dummy pop statements at end.
+ -- statements at start, and dummy pop statements at end, but inhibit
+ -- this if we have No_Exception_Handlers, since they are useless and
+ -- intefere with analysis, e.g. by codepeer.
if (Debug_Flag_Dot_G
or else Restriction_Active (No_Exception_Propagation))
+ and then not Restriction_Active (No_Exception_Handlers)
+ and then not CodePeer_Mode
and then Is_Non_Empty_List (L)
then
declare
