sim,cpu,mem,arch: Introduced MasterInfo data structure

With this patch a gem5 System will store more info about its Masters.
While it was previously keeping track of the Master name and Master ID
only, it is now adding a per-Master pointer to the SimObject related to
the Master.
This will make it possible for a client to query a System for a Master
using either the master's name or the master's pointer.

Change-Id: I8b97d328a65cd06f329e2cdd3679451c17d2b8f6
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/9781
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

2 files changed, 95 insertions, 22 deletions

diff --git a/src/sim/system.cc b/src/sim/system.cc
index 38eed1c2a..911ee5d9b 100644
--- a/src/sim/system.cc
+++ b/src/sim/system.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011-2014,2017 ARM Limited
+ * Copyright (c) 2011-2014,2017-2018 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -135,11 +135,11 @@ System::System(Params *p)
 
     // Get the generic system master IDs
     MasterID tmp_id M5_VAR_USED;
-    tmp_id = getMasterId("writebacks");
+    tmp_id = getMasterId(this, "writebacks");
     assert(tmp_id == Request::wbMasterId);
-    tmp_id = getMasterId("functional");
+    tmp_id = getMasterId(this, "functional");
     assert(tmp_id == Request::funcMasterId);
-    tmp_id = getMasterId("interrupt");
+    tmp_id = getMasterId(this, "interrupt");
     assert(tmp_id == Request::intMasterId);
 
     if (FullSystem) {
@@ -492,15 +492,27 @@ printSystems()
 }
 
 MasterID
-System::getMasterId(std::string master_name)
+System::getGlobalMasterId(std::string master_name)
+{
+    return _getMasterId(nullptr, master_name);
+}
+
+MasterID
+System::getMasterId(const SimObject* master, std::string submaster)
+{
+    auto master_name = leafMasterName(master, submaster);
+    return _getMasterId(master, master_name);
+}
+
+MasterID
+System::_getMasterId(const SimObject* master, std::string master_name)
 {
-    // strip off system name if the string starts with it
     if (startswith(master_name, name()))
         master_name = master_name.erase(0, name().size() + 1);
 
     // CPUs in switch_cpus ask for ids again after switching
-    for (int i = 0; i < masterIds.size(); i++) {
-        if (masterIds[i] == master_name) {
+    for (int i = 0; i < masters.size(); i++) {
+        if (masters[i].masterName == master_name) {
             return i;
         }
     }
@@ -514,18 +526,32 @@ System::getMasterId(std::string master_name)
                 "You must do so in init().\n");
     }
 
-    masterIds.push_back(master_name);
+    // Generate a new MasterID incrementally
+    MasterID master_id = masters.size();
+
+    // Append the new Master metadata to the group of system Masters.
+    masters.emplace_back(master, master_name, master_id);
+
+    return masters.back().masterId;
+}
 
-    return masterIds.size() - 1;
+std::string
+System::leafMasterName(const SimObject* master, const std::string& submaster)
+{
+    // Get the full master name by appending the submaster name to
+    // the root SimObject master name
+    auto master_name = master->name() + "." + submaster;
+    return master_name;
 }
 
 std::string
 System::getMasterName(MasterID master_id)
 {
-    if (master_id >= masterIds.size())
+    if (master_id >= masters.size())
         fatal("Invalid master_id passed to getMasterName()\n");
 
-    return masterIds[master_id];
+    const auto& master_info = masters[master_id];
+    return master_info.masterName;
 }
 
 System *
diff --git a/src/sim/system.hh b/src/sim/system.hh
index a72f2a762..0d26ffa0d 100644
--- a/src/sim/system.hh
+++ b/src/sim/system.hh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2014 ARM Limited
+ * Copyright (c) 2012, 2014, 2018 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -57,6 +57,7 @@
 #include "base/statistics.hh"
 #include "config/the_isa.hh"
 #include "enums/MemoryMode.hh"
+#include "mem/mem_master.hh"
 #include "mem/mem_object.hh"
 #include "mem/physical.hh"
 #include "mem/port.hh"
@@ -320,31 +321,77 @@ class System : public MemObject
      * It's used to uniquely id any master in the system by name for things
      * like cache statistics.
      */
-    std::vector<std::string> masterIds;
+    std::vector<MasterInfo> masters;
 
     ThermalModel * thermalModel;
 
   public:
 
-    /** Request an id used to create a request object in the system. All objects
+    /**
+     * Request an id used to create a request object in the system. All objects
      * that intend to issues requests into the memory system must request an id
      * in the init() phase of startup. All master ids must be fixed by the
      * regStats() phase that immediately precedes it. This allows objects in
      * the memory system to understand how many masters may exist and
      * appropriately name the bins of their per-master stats before the stats
-     * are finalized
+     * are finalized.
+     *
+     * Registers a MasterID:
+     * This method takes two parameters, one of which is optional.
+     * The first one is the master object, and it is compulsory; in case
+     * a object has multiple (sub)masters, a second parameter must be
+     * provided and it contains the name of the submaster. The method will
+     * create a master's name by concatenating the SimObject name with the
+     * eventual submaster string, separated by a dot.
+     *
+     * As an example:
+     * For a cpu having two masters: a data master and an instruction master,
+     * the method must be called twice:
+     *
+     * instMasterId = getMasterId(cpu, "inst");
+     * dataMasterId = getMasterId(cpu, "data");
+     *
+     * and the masters' names will be:
+     * - "cpu.inst"
+     * - "cpu.data"
+     *
+     * @param master SimObject related to the master
+     * @param submaster String containing the submaster's name
+     * @return the master's ID.
+     */
+    MasterID getMasterId(const SimObject* master,
+                         std::string submaster = std::string());
+
+    /**
+     * Registers a GLOBAL MasterID, which is a MasterID not related
+     * to any particular SimObject; since no SimObject is passed,
+     * the master gets registered by providing the full master name.
+     *
+     * @param masterName full name of the master
+     * @return the master's ID.
      */
-    MasterID getMasterId(std::string req_name);
+    MasterID getGlobalMasterId(std::string master_name);
 
-    /** Get the name of an object for a given request id.
+    /**
+     * Get the name of an object for a given request id.
      */
     std::string getMasterName(MasterID master_id);
 
     /** Get the number of masters registered in the system */
-    MasterID maxMasters()
-    {
-        return masterIds.size();
-    }
+    MasterID maxMasters() { return masters.size(); }
+
+  protected:
+    /** helper function for getMasterId */
+    MasterID _getMasterId(const SimObject* master, std::string master_name);
+
+    /**
+     * Helper function for constructing the full (sub)master name
+     * by providing the root master and the relative submaster name.
+     */
+    std::string leafMasterName(const SimObject* master,
+                               const std::string& submaster);
+
+  public:
 
     void regStats() override;
     /**