From a385d57921f33d71f753863eb21ec2a2fe81a4a6 Mon Sep 17 00:00:00 2001
From: Suraj Shirvankar <surajshirvankar@gmail.com>
Date: Tue, 31 Oct 2023 16:10:39 +0100
Subject: [PATCH] Raise exception in LSU when ROB is drained

---
 core/CPUFactory.cpp | 4 ++++
 core/LSU.cpp        | 8 ++++++++
 core/LSU.hpp        | 5 +++--
 core/ROB.cpp        | 7 +++++++
 core/ROB.hpp        | 2 ++
 5 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/core/CPUFactory.cpp b/core/CPUFactory.cpp
index 012e695b..62960b46 100644
--- a/core/CPUFactory.cpp
+++ b/core/CPUFactory.cpp
@@ -94,6 +94,10 @@ auto olympia::CPUFactory::bindTree_(sparta::RootTreeNode* root_node,
                 setTLB(*private_nodes_.at(num_of_cores)->getResourceAs<olympia::SimpleTLB>());
         (core_tree_node->getChild("preloader")->getResourceAs<olympia::Preloader>())->
             preload();
+        auto rob = core_tree_node->getChild("rob")->getResourceAs<olympia::ROB>()->getContainer();
+        auto lsu = core_tree_node->getChild("lsu")->getResourceAs<olympia::LSU>();
+        rob->registerForNotification<bool, LSU, &LSU::onRobDrained_>
+            (lsu, "rob_notif_channel");
     }
 }
 
diff --git a/core/LSU.cpp b/core/LSU.cpp
index 6aff42ed..76667d46 100644
--- a/core/LSU.cpp
+++ b/core/LSU.cpp
@@ -80,7 +80,10 @@ namespace olympia
         // Both cache and MMU try to drive the single BIU port at the same cycle
         // Here we give cache the higher priority
         ILOG("LSU construct: #" << node->getGroupIdx());
+    }
 
+    void LSU::onRobDrained_(const bool &val){
+        retire_done_and_is_drained_ = val;
     }
 
     LSU::~LSU()  {
@@ -92,6 +95,11 @@ namespace olympia
              << ": "
              << memory_access_allocator_.getNumAllocated()
              << " MemoryAccessInfo objects allocated/created");
+
+        if(retire_done_and_is_drained_){
+            bool ldst_queue_empty_ = ldst_inst_queue_.empty();
+            sparta_assert(ldst_queue_empty_, "Issue queue has pending instructions");
+        }
     }
 
     ////////////////////////////////////////////////////////////////////////////////
diff --git a/core/LSU.hpp b/core/LSU.hpp
index 81a94fa5..afb7e35b 100644
--- a/core/LSU.hpp
+++ b/core/LSU.hpp
@@ -69,7 +69,7 @@ namespace olympia
         // Type Name/Alias Declaration
         ////////////////////////////////////////////////////////////////////////////////
 
-
+        bool retire_done_and_is_drained_ = false;
         class LoadStoreInstInfo;
 
         using LoadStoreInstInfoPtr = sparta::SpartaSharedPointer<LoadStoreInstInfo>;
@@ -196,6 +196,8 @@ namespace olympia
                                   SPARTA_ADDPAIR("state", &LoadStoreInstInfo::getState),
                                   SPARTA_FLATTEN(         &LoadStoreInstInfo::getMemoryAccessInfoPtr))
         };
+
+        void onRobDrained_(const bool &val);
     private:
 
         using ScoreboardViews = std::array<std::unique_ptr<sparta::ScoreboardView>, core_types::N_REGFILES>;
@@ -293,7 +295,6 @@ namespace olympia
         ////////////////////////////////////////////////////////////////////////////////
         // Callbacks
         ////////////////////////////////////////////////////////////////////////////////
-
         // Send initial credits (ldst_inst_queue_size_) to Dispatch Unit
         void sendInitialCredits_();
 
diff --git a/core/ROB.cpp b/core/ROB.cpp
index 16dcf3d0..395ce1b7 100644
--- a/core/ROB.cpp
+++ b/core/ROB.cpp
@@ -53,6 +53,12 @@ namespace olympia
         // simulation continuing on.
         ev_ensure_forward_progress_.setContinuing(false);
 
+        rob_drained_notif_source_.reset(new sparta::NotificationSource<bool>(
+            this->getContainer(),
+            "rob_notif_channel",
+            "Notification channel for rob",
+            "rob_notif_channel"
+        ));
         // Send initial credits to anyone that cares.  Probably Dispatch.
         sparta::StartupEvent(node, CREATE_SPARTA_HANDLER(ROB, sendInitialCredits_));
     }
@@ -198,6 +204,7 @@ namespace olympia
 
     void ROB::onStartingTeardown_() {
         if ((reorder_buffer_.size() > 0) && (false == rob_stopped_simulation_)) {
+            rob_drained_notif_source_->postNotification(true);
             std::cerr << "WARNING! Simulation is ending, but the ROB didn't stop it.  Lock up situation?" << std::endl;
             dumpDebugContent_(std::cerr);
         }
diff --git a/core/ROB.hpp b/core/ROB.hpp
index f6a828cc..89aa83d4 100644
--- a/core/ROB.hpp
+++ b/core/ROB.hpp
@@ -116,6 +116,8 @@ namespace olympia
         sparta::Event<> ev_ensure_forward_progress_{&unit_event_set_, "forward_progress_check",
                 CREATE_SPARTA_HANDLER(ROB, checkForwardProgress_)};
 
+        std::unique_ptr<sparta::NotificationSource<bool>> rob_drained_notif_source_;
+
         void sendInitialCredits_();
         void retireEvent_();
         void robAppended_(const InstGroup &);