From 665a9313a4338e53b0f4e29c6688ecbaeec60293 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Tue, 12 Nov 2024 18:11:09 -0800
Subject: [PATCH] Valgrind annotations for new free list

---
 ConflictSet.cpp | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index c4b1a47..a642cd8 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -700,8 +700,6 @@ constexpr int64_t kMaxFreeListBytes = 1 << 20;
 // doesn't meet the capacity constraints, it's freed and a new node is allocated
 // with the minimum capacity. The hope is that "unfit" nodes don't get stuck in
 // the free list.
-//
-// TODO valgrind annotations
 template <class T> struct NodeAllocator {
 
   static_assert(std::derived_from<T, Node>);
@@ -738,6 +736,7 @@ template <class T> struct NodeAllocator {
     p->parent = freeList;
     freeList = p;
     freeListSize += sizeof(T) + p->partialKeyCapacity;
+    VALGRIND_MAKE_MEM_NOACCESS(p, sizeof(T) + p->partialKeyCapacity);
   }
 
   void deferRelease(T *p, Node *forwardTo) {
@@ -759,6 +758,13 @@ template <class T> struct NodeAllocator {
   void releaseDeferred() {
     if (deferredList != nullptr) {
       deferredListFront->parent = freeList;
+#ifndef NVALGRIND
+      for (auto *iter = deferredList; iter != freeList;) {
+        auto *tmp = iter;
+        iter = (T *)iter->parent;
+        VALGRIND_MAKE_MEM_NOACCESS(tmp, sizeof(T) + tmp->partialKeyCapacity);
+      }
+#endif
       freeList = std::exchange(deferredList, nullptr);
     }
     for (T *n = std::exchange(deferredListOverflow, nullptr); n != nullptr;) {
@@ -779,6 +785,7 @@ template <class T> struct NodeAllocator {
     assert(deferredList == nullptr);
     assert(deferredListOverflow == nullptr);
     for (T *iter = freeList; iter != nullptr;) {
+      VALGRIND_MAKE_MEM_DEFINED(iter, sizeof(T));
       auto *tmp = iter;
       iter = (T *)iter->parent;
       removeNode(tmp);
@@ -796,6 +803,7 @@ private:
 
   T *allocate_helper(int minCapacity, int maxCapacity) {
     if (freeList != nullptr) {
+      VALGRIND_MAKE_MEM_DEFINED(freeList, sizeof(T));
       freeListSize -= sizeof(T) + freeList->partialKeyCapacity;
       assume(freeList->partialKeyCapacity >= 0);
       assume(minCapacity >= 0);
@@ -804,6 +812,11 @@ private:
           freeList->partialKeyCapacity <= maxCapacity) {
         auto *result = freeList;
         freeList = (T *)freeList->parent;
+        VALGRIND_MAKE_MEM_UNDEFINED(result,
+                                    sizeof(T) + result->partialKeyCapacity);
+        VALGRIND_MAKE_MEM_DEFINED(&result->partialKeyCapacity,
+                                  sizeof(result->partialKeyCapacity));
+        VALGRIND_MAKE_MEM_DEFINED(&result->type, sizeof(result->type));
         return result;
       } else {
         auto *p = freeList;