Add GlobalVariableContext::{init,append}

Also added some throwaway test code to exercise the tls code I ported

src/sst/elements/mercury/operating_system/process/app.cc

@@ -113,6 +113,62 @@ GlobalVariable::init(const int size, const char* name, bool tls)
   else return glblCtx.append(size, name);
 }
 
+void
+GlobalVariableContext::init()
+{
+    stackOffset = 0;
+    allocSize_ = 4096;
+    globalInits = nullptr;
+}
+
+int
+GlobalVariableContext::append(const int size, const char*  /*name*/)
+{
+  int offset = stackOffset;
+
+  int rem = size % 4;
+  int offsetIncrement = rem ? (size + (4-rem)) : size; //align on 32-bits
+
+  bool realloc = false;
+  while ((offsetIncrement + stackOffset) > allocSize_){
+    realloc = true;
+    allocSize_ *= 2; //grow until big enough
+  }
+
+  if (realloc && !activeGlobalMaps_.empty()){
+    std::cerr << "dynamically loaded global variable overran storage space\n"
+                      "to fix, explicitly set globals_size = " << allocSize_ << " in app params" << "\n";
+  }
+
+  if (realloc || globalInits == nullptr){
+    char* old = globalInits;
+    globalInits = new char[allocSize_];
+    if (old){
+      //move everything in that was already there
+      ::memcpy(globalInits, old, stackOffset);
+      delete[] old;
+    }
+  }
+
+  //printf("Allocated global variable %s of size %d at offset %d - %s\n",
+  //       name, size, offset, (realloc ? "reallocated to fit" : "already fits"));
+  //fflush(stdout);
+
+  stackOffset += offsetIncrement;
+
+  return offset;
+}
+
+// <JML>
+// Temporary fix to trigger some of the code that I ported over
+extern "C" {
+  // This is the variable name in test_tls.cc
+  extern int my_global;
+}
+
+static auto foo = GlobalVariable::init(4, "my_global", true);
+// </JML>
+
 void
 GlobalVariableContext::callInitFxns(void *globals)
 {