Fix MSVCC issues (#3813)

include/verilatedos.h

@@ -231,10 +231,16 @@
         } while (false); \
     } while (false)
 
+#ifdef _MSC_VER
+# if _MSC_VER < 1929
+#  error "Verilator requires at least Visual Studio 2019 version 16.11.2"
+# endif
+#endif
+
 //=========================================================================
 // C++-2011
 
-#if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__) || defined(VL_CPPCHECK) || (defined(_MSC_VER) && _MSC_VER >= 1900)
+#if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__) || defined(VL_CPPCHECK) || defined(_MSC_VER)
 #else
 # error "Verilator requires a C++11 or newer compiler"
 #endif

src/V3Options.cpp

@@ -36,7 +36,12 @@
 #endif
 #include <algorithm>
 #include <cctype>
-#include <dirent.h>
+#ifdef _MSC_VER
+# include <filesystem> // C++17
+# define S_ISDIR(mode) (((mode) & _S_IFMT) == _S_IFDIR)
+#else
+# include <dirent.h>
+#endif
 #include <fcntl.h>
 #include <list>
 #include <map>
@@ -454,11 +459,17 @@ 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.
+#ifdef _MSC_VER
+    if (int fd = ::open(filename.c_str(), O_RDONLY)) {  // LCOV_EXCL_BR_LINE
+        if (fd > 0) ::close(fd);
+    }
+#else
     if (DIR* const dirp = opendir(filename.c_str())) {  // LCOV_EXCL_BR_LINE
         closedir(dirp);  // LCOV_EXCL_LINE
     } else if (int fd = ::open(filename.c_str(), O_RDONLY)) {  // LCOV_EXCL_BR_LINE
         if (fd > 0) ::close(fd);
     }
+#endif
 }
 
 string V3Options::fileExists(const string& filename) {
@@ -477,10 +488,15 @@ string V3Options::fileExists(const string& filename) {
 
         std::set<string>* setp = &(diriter->second);
 
+#ifdef _MSC_VER
+        for (const auto& dirEntry : std::filesystem::directory_iterator(dir.c_str()))
+            setp->insert(dirEntry.path().filename().string());
+#else
         if (DIR* const dirp = opendir(dir.c_str())) {
             while (struct dirent* direntp = readdir(dirp)) setp->insert(direntp->d_name);
             closedir(dirp);
         }
+#endif
     }
     // Find it
     const std::set<string>* filesetp = &(diriter->second);

src/V3Os.cpp

@@ -40,7 +40,12 @@ VL_DEFINE_DEBUG_FUNCTIONS;
 #include <cerrno>
 #include <climits>  // PATH_MAX (especially on FreeBSD)
 #include <cstdarg>
-#include <dirent.h>
+#ifdef _MSC_VER
+# include <filesystem> // C++17
+# define PATH_MAX MAX_PATH
+#else
+# include <dirent.h>
+#endif
 #include <fstream>
 #include <memory>
 
@@ -245,6 +250,14 @@ void V3Os::createDir(const string& dirname) {
 }
 
 void V3Os::unlinkRegexp(const string& dir, const string& regexp) {
+#ifdef _MSC_VER
+    for (const auto& dirEntry : std::filesystem::directory_iterator(dir.c_str())) {
+        if (VString::wildmatch(dirEntry.path().filename().string(), regexp.c_str())) {
+            const string fullname = dir + "/" + dirEntry.path().filename().string();
+            _unlink(fullname.c_str());
+        }
+    }
+#else
     if (DIR* const dirp = opendir(dir.c_str())) {
         while (struct dirent* const direntp = readdir(dirp)) {
             if (VString::wildmatch(direntp->d_name, regexp.c_str())) {
@@ -258,6 +271,7 @@ void V3Os::unlinkRegexp(const string& dir, const string& regexp) {
         }
         closedir(dirp);
     }
+#endif
 }
 
 //######################################################################

src/V3Sched.cpp

@@ -302,7 +302,7 @@ struct TriggerKit {
     // The map from input sensitivity list to trigger sensitivity list
     const std::unordered_map<const AstSenTree*, AstSenTree*> m_map;
 
-    VL_UNCOPYABLE(TriggerKit);
+    // No VL_UNCOPYABLE(TriggerKit) as causes C++20 errors on MSVC
 
     // Utility that assigns the given index trigger to fire when the given variable is zero
     void addFirstIterationTriggerAssignment(AstVarScope* counterp, uint32_t /*index*/) const {