commit 89df9512980c372b7d0079b7c5995182af387963
author Elliott Hughes <enh@google.com> Wed Oct 02 12:27:03 2019 -0700
committer Elliott Hughes <enh@google.com> Wed Oct 02 12:27:03 2019 -0700
tree aa5436e9ac808fef8f585baf3f4eb052a7e4be4d
parent 8840e1bc34fda0f022bcf88c808fd8e6f05f8ba8

liblog: replace crufty min macro with existing MIN.

The "branchless" macro generates slightly worse code than std::min or
<sys/param.h>'s MIN.

Test: treehugger
Change-Id: I92c17325383bd6116c7b4736d42f01f7a9bb81a3

liblog/logd_reader.cpp

diff --git a/liblog/logd_reader.cpp b/liblog/logd_reader.cpp
index e372dce..916a428 100644
--- a/liblog/logd_reader.cpp
+++ b/liblog/logd_reader.cpp
@@ -23,6 +23,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/param.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -38,9 +39,6 @@
 #include "logd_reader.h"
 #include "logger.h"
 
-/* branchless on many architectures. */
-#define min(x, y) ((y) ^ (((x) ^ (y)) & -((x) < (y))))
-
 static int logdAvailable(log_id_t LogId);
 static int logdVersion(struct android_log_logger* logger,
                        struct android_log_transport_context* transp);
@@ -278,13 +276,13 @@
   size_t n;
 
   n = snprintf(cp, remaining, "getStatistics");
-  n = min(n, remaining);
+  n = MIN(n, remaining);
   remaining -= n;
   cp += n;
 
   logger_for_each(logger, logger_list) {
     n = snprintf(cp, remaining, " %d", logger->logId);
-    n = min(n, remaining);
+    n = MIN(n, remaining);
     remaining -= n;
     cp += n;
   }
@@ -361,7 +359,7 @@
   remaining = sizeof(buffer) - (cp - buffer);
   logger_for_each(logger, logger_list) {
     ret = snprintf(cp, remaining, "%c%u", c, logger->logId);
-    ret = min(ret, remaining);
+    ret = MIN(ret, remaining);
     remaining -= ret;
     cp += ret;
     c = ',';
@@ -369,7 +367,7 @@
 
   if (logger_list->tail) {
     ret = snprintf(cp, remaining, " tail=%u", logger_list->tail);
-    ret = min(ret, remaining);
+    ret = MIN(ret, remaining);
     remaining -= ret;
     cp += ret;
   }
@@ -378,20 +376,20 @@
     if (logger_list->mode & ANDROID_LOG_WRAP) {
       // ToDo: alternate API to allow timeout to be adjusted.
       ret = snprintf(cp, remaining, " timeout=%u", ANDROID_LOG_WRAP_DEFAULT_TIMEOUT);
-      ret = min(ret, remaining);
+      ret = MIN(ret, remaining);
       remaining -= ret;
       cp += ret;
     }
     ret = snprintf(cp, remaining, " start=%" PRIu32 ".%09" PRIu32, logger_list->start.tv_sec,
                    logger_list->start.tv_nsec);
-    ret = min(ret, remaining);
+    ret = MIN(ret, remaining);
     remaining -= ret;
     cp += ret;
   }
 
   if (logger_list->pid) {
     ret = snprintf(cp, remaining, " pid=%u", logger_list->pid);
-    ret = min(ret, remaining);
+    ret = MIN(ret, remaining);
     cp += ret;
   }
 

liblog/logd_writer.cpp

diff --git a/liblog/logd_writer.cpp b/liblog/logd_writer.cpp
index 09aaffb..06a2baf 100644
--- a/liblog/logd_writer.cpp
+++ b/liblog/logd_writer.cpp
@@ -38,9 +38,6 @@
 #include "logger.h"
 #include "uio.h"
 
-/* branchless on many architectures. */
-#define min(x, y) ((y) ^ (((x) ^ (y)) & -((x) < (y))))
-
 static int logdAvailable(log_id_t LogId);
 static int logdOpen();
 static void logdClose();