ivl: Don’t embed paths in generated .vvp

To satisfy the “don’t embed paths in generated .vvp” goal, add_vpi_module()
has been changed so the value recorded into VPI_MODULE_LIST is normalized
to a name-only module id (strip directory and .vpi/.vpl suffix), while
load_vpi_module(name) still receives the original full/pathful value
for loading.

This means:
- compile-time module loading keeps working from build dirs,
- emitted :vpi_module entries are path-independent names.

main.cc

@@ -131,18 +131,35 @@ map<string,const char*> flags;
 char*vpi_module_list = 0;
 void add_vpi_module(const char*name)
 {
+      const char*module_name = strrchr(name, '/');
+#ifdef __MINGW32__
+      const char*module_name2 = strrchr(name, '\\');
+      if (!module_name || (module_name2 && module_name2 > module_name))
+	    module_name = module_name2;
+#endif
+      module_name = module_name ? module_name + 1 : name;
+
+      char*module_base = strdup(module_name);
+      size_t module_len = strlen(module_base);
+      if (module_len > 4 && strcmp(module_base + module_len - 4, ".vpi") == 0) {
+	    module_base[module_len - 4] = 0;
+      } else if (module_len > 4 && strcmp(module_base + module_len - 4, ".vpl") == 0) {
+	    module_base[module_len - 4] = 0;
+      }
+
       if (vpi_module_list == 0) {
-	    vpi_module_list = strdup(name);
+	    vpi_module_list = strdup(module_base);
 
       } else {
 	    char*tmp = static_cast<char*>(realloc(vpi_module_list,
 	                                  strlen(vpi_module_list)
-	                                  + strlen(name)
+	                                  + strlen(module_base)
 	                                  + 2));
 	    strcat(tmp, ",");
-	    strcat(tmp, name);
+	    strcat(tmp, module_base);
 	    vpi_module_list = tmp;
       }
+      free(module_base);
       flags["VPI_MODULE_LIST"] = vpi_module_list;
       load_vpi_module(name);
 }

vpi_modules.cc

@@ -23,6 +23,8 @@
 #include "sv_vpi_user.h"
 #include "ivl_dlfcn.h"
 
+#include <string.h>
+
 using namespace std;
 
 /* The only VPI routines that can be legally called when the functions in
@@ -241,11 +243,27 @@ typedef void (*vlog_startup_routines_t)(void);
 
 bool load_vpi_module(const char*path)
 {
-    ivl_dll_t dll = ivl_dlopen(path, false);
-    if (dll == 0) {
-	cerr << "error: Failed to open '" << path << "' because:" << endl;
-        cerr << "     : " << dlerror() << endl;
-	return false;
+    ivl_dll_t dll = NULL;;
+    if (strchr(path, '/') != NULL || strchr(path, '\\') != NULL) {
+        dll = ivl_dlopen(path, false);
+        if (dll == 0) {
+            cerr << "error: Failed to open +++'" << path << "' because:" << endl;
+            cerr << "     : " << dlerror() << endl;
+            return false;
+        }
+    } else {
+        const char *suffix = ".vpi";
+	    size_t len = strlen(basedir) + 1 + strlen(path) + strlen(suffix) + 1;
+	    char*tmp = new char[len];
+	    snprintf(tmp, len, "%s/%s%s", basedir, path, suffix);
+        dll = ivl_dlopen(tmp, false);
+        if (dll == 0) {
+            cerr << "error: Failed to open ---'" << tmp << "' because:" << endl;
+            cerr << "     : " << dlerror() << endl;
+            delete[] tmp;
+            return false;
+        }
+        delete[] tmp;
     }
 
 #if defined(__MINGW32__) || defined (__CYGWIN__)