diff mbox series

[Ada] Remove warnings-as-errors about constraints error in dead code

Message ID 20220111133159.GA748519@adacore.com
State New
Headers show
Series [Ada] Remove warnings-as-errors about constraints error in dead code | expand

Commit Message

Pierre-Marie de Rodat Jan. 11, 2022, 1:31 p.m. UTC 
GNAT removes error messages attached to nodes within dead code; in
particular, within instances of generic units with alternative branches
for different generic formal types and parameters. Now this removal also
works for error messages that come from warnings about constraint errors
that have been escalated into hard errors due to -gnatwE switch.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

	* erroutc.ads, erroutc.adb (Is_Runtime_Raise): Global flag to
	connect status of initial messages and their continuation; we
	already have several flags like this.
	(Error_Msg_Object): Add field Warn_Runtime_Raise to connect
	error reporting (when problematic code is found) and removal
	(when problematic code is determined to be dead).
	* errout.adb (Error_Msg_Internal): Handle new field when
	recording a continuation message; propagate status from
	continuation to the preceding messages.
	(To_Be_Removed): For dead code remove both simple warnings and
	warnings about constraint errors that have been escalated to
	hard errors.
	(Set_Msg_Text): Recognize warnings about constraint errors that
	are escalated to hard errors.
	* errutil.adb (Error_Msg): Handle added field when recording a
	new message.
diff mbox series

Patch

diff --git a/gcc/ada/errout.adb b/gcc/ada/errout.adb
--- a/gcc/ada/errout.adb
+++ b/gcc/ada/errout.adb
@@ -1224,6 +1224,7 @@  package body Errout is
           Check               => Is_Check_Msg,
           Warn_Err            => False, -- reset below
           Warn_Chr            => Warning_Msg_Char,
+          Warn_Runtime_Raise  => Is_Runtime_Raise,
           Style               => Is_Style_Msg,
           Serious             => Is_Serious_Error,
           Uncond              => Is_Unconditional_Msg,
@@ -1241,12 +1242,14 @@  package body Errout is
                     Warning_Treated_As_Error (Get_Warning_Tag (Cur_Msg)));
 
       --  Propagate Warn_Err to this message and preceding continuations.
-      --  Likewise, propagate Is_Warning_Msg, because the current continued
-      --  message could have been escalated from warning to error.
+      --  Likewise, propagate Is_Warning_Msg and Is_Runtime_Raise, because the
+      --  current continued message could have been escalated from warning to
+      --  error.
 
       for J in reverse 1 .. Errors.Last loop
-         Errors.Table (J).Warn_Err := Warn_Err;
-         Errors.Table (J).Warn     := Is_Warning_Msg;
+         Errors.Table (J).Warn_Err           := Warn_Err;
+         Errors.Table (J).Warn               := Is_Warning_Msg;
+         Errors.Table (J).Warn_Runtime_Raise := Is_Runtime_Raise;
          exit when not Errors.Table (J).Msg_Cont;
       end loop;
 
@@ -3290,13 +3293,17 @@  package body Errout is
                --  not remove style messages here. They are warning messages
                --  but not ones we want removed in this context.
 
-               and then Errors.Table (E).Warn
+               and then (Errors.Table (E).Warn
+                           or else
+                         Errors.Table (E).Warn_Runtime_Raise)
 
                --  Don't remove unconditional messages
 
                and then not Errors.Table (E).Uncond
             then
-               Warnings_Detected := Warnings_Detected - 1;
+               if Errors.Table (E).Warn then
+                  Warnings_Detected := Warnings_Detected - 1;
+               end if;
 
                if Errors.Table (E).Info then
                   Warning_Info_Messages := Warning_Info_Messages - 1;
@@ -4072,7 +4079,8 @@  package body Errout is
                if Is_Warning_Msg
                  and then Warning_Mode = Treat_Run_Time_Warnings_As_Errors
                then
-                  Is_Warning_Msg := False;
+                  Is_Warning_Msg   := False;
+                  Is_Runtime_Raise := True;
                end if;
 
                if Is_Warning_Msg then


diff --git a/gcc/ada/erroutc.adb b/gcc/ada/erroutc.adb
--- a/gcc/ada/erroutc.adb
+++ b/gcc/ada/erroutc.adb
@@ -902,6 +902,7 @@  package body Erroutc is
          Is_Serious_Error     := True;
          Is_Unconditional_Msg := False;
          Is_Warning_Msg       := False;
+         Is_Runtime_Raise     := False;
 
          --  Check style message
 


diff --git a/gcc/ada/erroutc.ads b/gcc/ada/erroutc.ads
--- a/gcc/ada/erroutc.ads
+++ b/gcc/ada/erroutc.ads
@@ -71,6 +71,11 @@  package Erroutc is
    --  Set True to indicate if current message is warning message (contains ?
    --  or contains < and Error_Msg_Warn is True).
 
+   Is_Runtime_Raise : Boolean := False;
+   --  Set to True to indicate that the current message is a warning about a
+   --  constraint error that will be raised at runtime (contains [ and switch
+   --  -gnatwE was given).
+
    Is_Info_Msg : Boolean := False;
    --  Set True to indicate that the current message starts with the characters
    --  "info: " and is to be treated as an information message. This string
@@ -239,6 +244,10 @@  package Erroutc is
       --  True if this is a warning message which is to be treated as an error
       --  as a result of a match with a Warning_As_Error pragma.
 
+      Warn_Runtime_Raise : Boolean;
+      --  True if this a warning about a constraint error that will be raised
+      --  at runtime.
+
       Warn_Chr : String (1 .. 2);
       --  See Warning_Msg_Char
 


diff --git a/gcc/ada/errutil.adb b/gcc/ada/errutil.adb
--- a/gcc/ada/errutil.adb
+++ b/gcc/ada/errutil.adb
@@ -217,6 +217,7 @@  package body Errutil is
             Info                => Is_Info_Msg,
             Check               => Is_Check_Msg,
             Warn_Err            => Warning_Mode = Treat_As_Error,
+            Warn_Runtime_Raise  => Is_Runtime_Raise,
             Warn_Chr            => Warning_Msg_Char,
             Style               => Is_Style_Msg,
             Serious             => Is_Serious_Error,