Force extension loaders to be linked in

riscv/extension.cc

@@ -1,12 +1,6 @@
 #include "extension.h"
 #include "trap.h"
 
-std::map<std::string, std::function<extension_t*()>>& extensions()
-{
-  static std::map<std::string, std::function<extension_t*()>> v;
-  return v;
-}
-
 extension_t::~extension_t()
 {
 }

spike/extensions.cc

@@ -1 +1,11 @@
+#include "extension.h"
 #include "hwacha.h"
+#include "dummy-rocc.h"
+
+// Static constructors want to make use of the extensions map, so we
+// access it through a function call to guarantee initialization order.
+std::map<std::string, std::function<extension_t*()>>& extensions()
+{
+  static std::map<std::string, std::function<extension_t*()>> v;
+  return v;
+}