Make alert_dispatch into a bool.

Due to padding and slightly silly field ordering, I think this actually ends up
a no-op memory-wise, but may amount to win with cleverer reordering or as
fields change.

Change-Id: I14e38d747a90112cf06c741aec148b77cc5902fb
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/36791
Reviewed-by: Adam Langley <agl@google.com>

ssl/d1_pkt.cc

diff --git a/ssl/d1_pkt.cc b/ssl/d1_pkt.cc
index be595b0..dfb8a67 100644
--- a/ssl/d1_pkt.cc
+++ b/ssl/d1_pkt.cc
@@ -256,7 +256,7 @@
   if (ret <= 0) {
     return ret;
   }
-  ssl->s3->alert_dispatch = 0;
+  ssl->s3->alert_dispatch = false;
 
   // If the alert is fatal, flush the BIO now.
   if (ssl->s3->send_alert[0] == SSL3_AL_FATAL) {

ssl/internal.h

diff --git a/ssl/internal.h b/ssl/internal.h
index 5a787b8..b355c7f 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -2173,8 +2173,6 @@
   // the receive half of the connection.
   UniquePtr<ERR_SAVE_STATE> read_error;
 
-  int alert_dispatch = 0;
-
   int total_renegotiations = 0;
 
   // This holds a variable that indicates what we were doing when a 0 or -1 is
@@ -2261,6 +2259,9 @@
   // sending/echoing the post-quantum experiment signal.
   bool pq_experiment_signal_seen : 1;
 
+  // alert_dispatch is true there is an alert in |send_alert| to be sent.
+  bool alert_dispatch : 1;
+
   // hs_buf is the buffer of handshake data to process.
   UniquePtr<BUF_MEM> hs_buf;
 

ssl/s3_lib.cc

diff --git a/ssl/s3_lib.cc b/ssl/s3_lib.cc
index 75e1f68..41dd588 100644
--- a/ssl/s3_lib.cc
+++ b/ssl/s3_lib.cc
@@ -180,7 +180,8 @@
       early_data_accepted(false),
       tls13_downgrade(false),
       token_binding_negotiated(false),
-      pq_experiment_signal_seen(false) {}
+      pq_experiment_signal_seen(false),
+      alert_dispatch(false) {}
 
 SSL3_STATE::~SSL3_STATE() {}
 

ssl/s3_pkt.cc

diff --git a/ssl/s3_pkt.cc b/ssl/s3_pkt.cc
index 67bfd63..a54bb00 100644
--- a/ssl/s3_pkt.cc
+++ b/ssl/s3_pkt.cc
@@ -414,7 +414,7 @@
     ssl->s3->write_shutdown = ssl_shutdown_error;
   }
 
-  ssl->s3->alert_dispatch = 1;
+  ssl->s3->alert_dispatch = true;
   ssl->s3->send_alert[0] = level;
   ssl->s3->send_alert[1] = desc;
   if (ssl->s3->write_buffer.empty()) {
@@ -441,7 +441,7 @@
     }
   }
 
-  ssl->s3->alert_dispatch = 0;
+  ssl->s3->alert_dispatch = false;
 
   // If the alert is fatal, flush the BIO now.
   if (ssl->s3->send_alert[0] == SSL3_AL_FATAL) {