BR 3392539: some errors can "cascade". Allow suppressing if dead.

In BR 3392539, the error:

helloW.s:18: error: label `rurt' changed during code generation
[-w+error=label-redef-late]

... occurs a number of times after we have already issued an
error. This is because the erroring instruction computes to a
different size during code generation; this causes each subsequent
label to cause a phase error.

The phase error simply doesn't make much sense to report: if we are
already committed to erroring out, it is more likely an error cascade
rather than an error in its own right, so just suppress it in that
case.

Reported-by: <russvz@comcast.net>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/asm/nasm.c b/asm/nasm.c
index 1c5a5fc5..1037166f 100644
--- a/asm/nasm.c
+++ b/asm/nasm.c
@@ -1775,8 +1775,13 @@ static bool skip_this_pass(int severity)
  */
 static bool is_suppressed(int severity)
 {
+    /* Fatal errors must never be suppressed */
     if ((severity & ERR_MASK) >= ERR_FATAL)
-        return false;           /* Fatal errors can never be suppressed */
+        return false;
+
+    /* This error/warning is pointless if we are dead anyway */
+    if ((severity & ERR_UNDEAD) && terminate_after_phase)
+        return true;
 
     return !(warning_state[warn_index(severity)] & WARN_ST_ENABLED);
 }