Accommodate Windows-style paths during include-file processing.

diff --git a/frontends/verilog/preproc.cc b/frontends/verilog/preproc.cc
index ee742d485d116dcc90db64809586ab5ba8b7f144..00bdcee4365ffaab23d19b05bff6bd1bb6bd18c2 100644 (file)
--- a/frontends/verilog/preproc.cc
+++ b/frontends/verilog/preproc.cc
@@ -366,14 +366,31 @@ std::string frontend_verilog_preproc(std::istream &f, std::string filename, cons
                        ff.clear();
                        std::string fixed_fn = fn;
                        ff.open(fixed_fn.c_str());
-                       if (ff.fail() && fn.size() > 0 && fn[0] != '/' && filename.find('/') != std::string::npos) {
+
+                       bool filename_path_sep_found;
+                       bool fn_relative;
+#ifdef _WIN32
+                       // Both forward and backslash are acceptable separators on Windows.
+                       filename_path_sep_found = (filename.find_first_of("/\\") != std::string::npos);
+                       // Easier just to invert the check for an absolute path (e.g. C:\ or C:/)
+                       fn_relative = !(fn[1] == ':' && (fn[2] == '/' || fn[2] == '\\'));
+#else
+                       filename_path_sep_found = (filename.find('/') != std::string::npos);
+                       fn_relative = (fn[0] != '/');
+#endif
+
+                       if (ff.fail() && fn.size() > 0 && fn_relative && filename_path_sep_found) {
                                // if the include file was not found, it is not given with an absolute path, and the
                                // currently read file is given with a path, then try again relative to its directory
                                ff.clear();
+#ifdef _WIN32
+                               fixed_fn = filename.substr(0, filename.find_last_of("/\\")+1) + fn;
+#else
                                fixed_fn = filename.substr(0, filename.rfind('/')+1) + fn;
+#endif
                                ff.open(fixed_fn);
                        }
-                       if (ff.fail() && fn.size() > 0 && fn[0] != '/') {
+                       if (ff.fail() && fn.size() > 0 && fn_relative) {
                                // if the include file was not found and it is not given with an absolute path, then
                                // search it in the include path
                                for (auto incdir : include_dirs) {
@@ -505,7 +522,7 @@ std::string frontend_verilog_preproc(std::istream &f, std::string filename, cons
 
                if (try_expand_macro(defines_with_args, defines_map, tok))
                        continue;
-               
+
                output_code.push_back(tok);
        }
 
@@ -521,4 +538,3 @@ std::string frontend_verilog_preproc(std::istream &f, std::string filename, cons
 }
 
 YOSYS_NAMESPACE_END
-