https://gcc.gnu.org/g:b3eef3b124d1eee9cd261fb072d6e1667cd2501a
commit r15-417-gb3eef3b124d1eee9cd261fb072d6e1667cd2501a
Author: Bob Duff <d...@adacore.com>
Date: Wed Jan 31 09:30:06 2024 -0500
ada: Fix crash on Compile_Time_Warning in dead code
If a pragma Compile_Time_Warning triggers, and the pragma
is later removed because it is dead code, then the compiler
can return a bad exit code. This causes gprbuild to report
"*** compilation phase failed".
This is because Total_Errors_Detected, which is declared as Nat,
goes negative, causing Constraint_Error. In assertions-off mode,
the Constraint_Error is not detected, but the compiler nonetheless
reports a bad exit code.
This patch prevents that negative count.
gcc/ada/
* errout.adb (Output_Messages): Protect against the total going
negative.
Diff:
---
gcc/ada/errout.adb | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/gcc/ada/errout.adb b/gcc/ada/errout.adb
index d28a410f47b7..c4761bd1bc9e 100644
--- a/gcc/ada/errout.adb
+++ b/gcc/ada/errout.adb
@@ -3399,11 +3399,16 @@ package body Errout is
if Warning_Mode = Treat_As_Error then
declare
- Compile_Time_Pragma_Warnings : constant Int :=
+ Compile_Time_Pragma_Warnings : constant Nat :=
Count_Compile_Time_Pragma_Warnings;
- begin
- Total_Errors_Detected := Total_Errors_Detected + Warnings_Detected
+ Total : constant Int := Total_Errors_Detected + Warnings_Detected
- Warning_Info_Messages - Compile_Time_Pragma_Warnings;
+ -- We need to protect against a negative Total here, because
+ -- if a pragma Compile_Time_Warning occurs in dead code, it
+ -- gets counted in Compile_Time_Pragma_Warnings but not in
+ -- Warnings_Detected.
+ begin
+ Total_Errors_Detected := Int'Max (Total, 0);
Warnings_Detected :=
Warning_Info_Messages + Compile_Time_Pragma_Warnings;
end;
