Remove slow sync() call for NFS flushing.

src/V3File.cpp

@@ -162,13 +162,11 @@ inline void V3FileDependImp::writeTimes(const string& filename, const string& cm
     *ofp<<"# DESCR"<<"IPTION: Verilator output: Timestamp data for --skip-identical.  Delete at will."<<endl;
     *ofp<<"C \""<<cmdline<<"\""<<endl;
 
-#ifndef _WIN32
-    sync();  // Push files so sizes look correct
-#endif
     for (set<DependFile>::iterator iter=m_filenameList.begin();
 	 iter!=m_filenameList.end(); ++iter) {
 	// Read stats of files we create after we're done making them (execpt for this file, of course)
 	DependFile* dfp = (DependFile*)&(*iter);
+	V3Options::fileNfsFlush(dfp->filename());
 	dfp->loadStats();
 	off_t showSize = iter->size();
 	if (dfp->filename() == filename) showSize=0;  // We're writing it, so need to ignore it

src/V3Options.cpp

@@ -28,6 +28,7 @@
 #include <cctype>
 #include <dirent.h>
 #include <unistd.h>
+#include <fcntl.h>
 #include <set>
 #include <list>
 #include <map>
@@ -277,6 +278,17 @@ bool V3Options::fileStatNormal(const string& filename) {
     return true;
 }
 
+void V3Options::fileNfsFlush(const string& filename) {
+    // NFS caches stat() calls so to get up-to-date information must
+    // do a open or opendir on the filename.
+    // Faster to just try both rather than check if a file is a dir.
+    if (DIR* dirp = opendir(filename.c_str())) {
+	closedir(dirp);
+    } else if (int fd = ::open(filename.c_str(), O_RDONLY)) {
+	if (fd>0) ::close(fd);
+    }
+}
+
 string V3Options::fileExists (const string& filename) {
     // Surprisingly, for VCS and other simulators, this process
     // is quite slow; presumably because of re-reading each directory

src/V3Options.h

@@ -36,6 +36,7 @@
 
 class V3OptionsImp;
 class FileLine;
+struct stat;
 
 typedef vector<string> V3StringList;
 typedef set<string> V3StringSet;
@@ -321,6 +322,7 @@ class V3Options {
     V3LangCode fileLanguage(const string &filename);
     static bool fileStatDir (const string& filename);
     static bool fileStatNormal (const string& filename);
+    static void fileNfsFlush(const string& filename);
 
     // METHODS (other OS)
     static void throwSigsegv();