[Bug modula2/108261] modula-2 module registration process seems to fail with shared libraries.

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108261

--- Comment #26 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Gaius Mulley from comment #25)
> Created attachment 54516 [details]
> Proposed fix version 6
> 
> Version 6 (more coroutine tests) and RTint.mod with more descriptive
> variable names.

This does not solve the timeout issues on Darwin (mentioned here because we
were wondering if the issue was related to init ordering).

-----

Here's a patch that seems to prevent the hangs (but at the expense of a lot of
diagnostic output - it seems modula-2 is somehow calling the OS select with
some bad input) .. I cannot reproduce this calling it from C.

>From 92cc7b7c19735ea32e0800b369a2e49f85047e27 Mon Sep 17 00:00:00 2001
From: Iain Sandoe <iain@sandoe.co.uk>
Date: Thu, 23 Feb 2023 09:54:01 +0000
Subject: [PATCH] modula-2 : Some TLC for  select fail case diagnostics

---
 gcc/m2/gm2-libs/RTint.mod | 52 ++++++++++++++++++++++++++-------------
 1 file changed, 35 insertions(+), 17 deletions(-)

diff --git a/gcc/m2/gm2-libs/RTint.mod b/gcc/m2/gm2-libs/RTint.mod
index d8ca8dd5694..796430a55df 100644
--- a/gcc/m2/gm2-libs/RTint.mod
+++ b/gcc/m2/gm2-libs/RTint.mod
@@ -669,6 +669,7 @@ PROCEDURE Listen (untilInterrupt: BOOLEAN;
 VAR
    found: BOOLEAN ;
    r    : INTEGER ;
+   zero,
    after,
    b4,
    t    : Timeval ;
@@ -742,6 +743,7 @@ BEGIN
       ELSE
          GetTime (t, s, m) ;
          Assert (m<Microseconds) ;
+         zero := InitTime (0, 0) ;
          b4 := InitTime (0, 0) ;
          after := InitTime (0, 0) ;
          r := GetTimeOfDay (b4) ;
@@ -762,23 +764,35 @@ BEGIN
             IF r=-1
             THEN
                perror ("select") ;
-               r := select (maxFd+1, i, o, NIL, NIL) ;
-               IF r=-1
+               r := select (maxFd+1, i, o, NIL, zero) ;
+               IF r#-1
                THEN
-                  perror ("select timeout argument is faulty")
-               END ;
-               r := select (maxFd+1, i, NIL, NIL, t) ;
-               IF r=-1
-               THEN
-                  perror ("select output fd argument is faulty")
-               END ;
-               r := select (maxFd+1, NIL, o, NIL, t) ;
-               IF r=-1
-               THEN
-                  perror ("select input fd argument is faulty")
+                  perror ("select timeout argument was faulty")
                ELSE
-                  perror ("select maxFD+1 argument is faulty")
-               END
+                 r := select (maxFd+1, i, NIL, NIL, t) ;
+                 IF r#-1
+                 THEN
+                    perror ("select output fd argument was faulty")
+                 ELSE
+                    r := select (maxFd+1, NIL, o, NIL, t) ;
+                    IF r#-1
+                    THEN
+                       perror ("select input fd argument was faulty")
+                    ELSE
+                       IF maxFd=-1
+                       THEN
+                          r := select (0, NIL, NIL, NIL, t) ;
+                          IF r=-1
+                          THEN
+                             perror ("select does not accept nfds == 0 ") ;
+                             r := 0
+                          END
+                       ELSE
+                          perror ("select maxFD+1 argument was faulty") ;
+                       END
+                    END
+                 END
+              END
             END
          UNTIL r#-1
       END ;
@@ -791,11 +805,15 @@ BEGIN
       END ;
       IF after#NIL
       THEN
-         t := KillTime (after)
+         after := KillTime (after)
       END ;
       IF b4#NIL
       THEN
-         t := KillTime (b4)
+         b4 := KillTime (b4)
+      END ;
+      IF zero#NIL
+      THEN
+         zero := KillTime (zero)
       END ;
       IF i#NIL
       THEN
-- 
2.24.3 (Apple Git-128)