Fix case when file does not exist

diff --git a/kernel/register.cc b/kernel/register.cc
index 4f1501330364dfacaba471c5e239de75222a23ad..4c6e3591f7d960d9e0c4a72676ae5a8fb2fd0b3b 100644 (file)
--- a/kernel/register.cc
+++ b/kernel/register.cc
@@ -456,25 +456,27 @@ void Frontend::extra_args(std::istream *&f, std::string &filename, std::vector<s
                                delete ff;
                        else
                                f = ff;
-                       // Check for gzip magic
-                       unsigned char magic[3];
-                       int n = readsome(*ff, reinterpret_cast<char*>(magic), 3);
-                       if (n == 3 && magic[0] == 0x1f && magic[1] == 0x8b) {
-#ifdef YOSYS_ENABLE_ZLIB
-                               log("Found gzip magic in file `%s', decompressing using zlib.\n", filename.c_str());
-                               if (magic[2] != 8)
-                                       log_cmd_error("gzip file `%s' uses unsupported compression type %02x\n",
-                                               filename.c_str(), unsigned(magic[2]));
-                               delete ff;
-                               std::stringstream *df = new std::stringstream();
-                               decompress_gzip(filename, *df);
-                               f = df;
-#else
-                               log_cmd_error("File `%s' is a gzip file, but Yosys is compiled without zlib.\n", filename.c_str());
-#endif
-                       } else {
-                               ff->clear();
-                               ff->seekg(0, std::ios::beg);
+                       if (f != NULL) {
+                               // Check for gzip magic
+                               unsigned char magic[3];
+                               int n = readsome(*ff, reinterpret_cast<char*>(magic), 3);
+                               if (n == 3 && magic[0] == 0x1f && magic[1] == 0x8b) {
+       #ifdef YOSYS_ENABLE_ZLIB
+                                       log("Found gzip magic in file `%s', decompressing using zlib.\n", filename.c_str());
+                                       if (magic[2] != 8)
+                                               log_cmd_error("gzip file `%s' uses unsupported compression type %02x\n",
+                                                       filename.c_str(), unsigned(magic[2]));
+                                       delete ff;
+                                       std::stringstream *df = new std::stringstream();
+                                       decompress_gzip(filename, *df);
+                                       f = df;
+       #else
+                                       log_cmd_error("File `%s' is a gzip file, but Yosys is compiled without zlib.\n", filename.c_str());
+       #endif
+                               } else {
+                                       ff->clear();
+                                       ff->seekg(0, std::ios::beg);
+                               }
                        }
                }
                if (f == NULL)