Fully interleaved range read

Would be great to find a way to make this all more readable

ConflictSet.cpp

@@ -2488,102 +2488,6 @@ downLeftSpine:
   return n->entry.rangeVersion <= readVersion;
 }
 
-namespace {
-// Return true if the max version among all keys that start with key[:prefixLen]
-// that are < key is <= readVersion
-bool checkRangeRightSide(Node *n, std::span<const uint8_t> key, int prefixLen,
-                         InternalVersionT readVersion, ReadContext *tls) {
-  auto remaining = key;
-
-  assert(remaining.size() > 0);
-
-  if (prefixLen == 0) {
-    if (n->entryPresent && n->entry.pointVersion > readVersion) {
-      return false;
-    }
-
-    if (!checkMaxBetweenExclusive(n, -1, remaining[0], readVersion, tls)) {
-      return false;
-    }
-  }
-
-  Node *commonPrefixNode = n;
-
-  for (;;) {
-    Node *child = getChild(n, remaining[0]);
-    if (child == nullptr) {
-      auto c = getChildGeq(n, remaining[0]);
-      if (c != nullptr) {
-        n = c;
-        goto downLeftSpine;
-      } else {
-        if (n != commonPrefixNode && maxVersion(n) > readVersion) {
-          return false;
-        }
-        n = nextSibling(n);
-        if (n == nullptr) {
-          return true;
-        }
-        goto downLeftSpine;
-      }
-    }
-
-    n = child;
-    remaining = remaining.subspan(1, remaining.size() - 1);
-
-    if (n->partialKeyLen > 0) {
-      int commonLen = std::min<int>(n->partialKeyLen, remaining.size());
-      int i = longestCommonPrefix(n->partialKey(), remaining.data(), commonLen);
-      if (i < commonLen) {
-        auto c = n->partialKey()[i] <=> remaining[i];
-        if (c > 0) {
-          goto downLeftSpine;
-        } else {
-          if ((n->parent != commonPrefixNode || i + 1 >= prefixLen) &&
-              n->entryPresent && n->entry.rangeVersion > readVersion) {
-            return false;
-          }
-          if ((n->parent != commonPrefixNode || i + 1 >= prefixLen) &&
-              maxVersion(n) > readVersion) {
-            return false;
-          }
-          n = nextSibling(n);
-          if (n == nullptr) {
-            return true;
-          }
-          goto downLeftSpine;
-        }
-      }
-      if (commonLen == n->partialKeyLen) {
-        // partial key matches
-        remaining = remaining.subspan(commonLen, remaining.size() - commonLen);
-      } else if (n->partialKeyLen > int(remaining.size())) {
-        goto downLeftSpine;
-      }
-    }
-
-    ++tls->range_read_iterations_accum;
-
-    if (remaining.size() == 0) {
-      goto downLeftSpine;
-    }
-
-    if (n->entryPresent && (n->entry.pointVersion > readVersion ||
-                            n->entry.rangeVersion > readVersion)) {
-      return false;
-    }
-
-    if (!checkMaxBetweenExclusive(n, -1, remaining[0], readVersion, tls)) {
-      return false;
-    }
-  }
-downLeftSpine:
-  for (; !n->entryPresent; n = getFirstChildExists(n)) {
-  }
-  return n->entry.rangeVersion <= readVersion;
-}
-} // namespace
-
 #ifdef __x86_64__
 // Explicitly instantiate with target avx512f attribute so the compiler can
 // inline compare16_32bit_avx512, and generally use avx512f within more
@@ -3289,6 +3193,13 @@ static Continuation leftSideIterTable[] = {
     left_side_iter<Node0>, left_side_iter<Node3>, left_side_iter<Node16>,
     left_side_iter<Node48>, left_side_iter<Node256>};
 
+template <class NodeT>
+PRESERVE_NONE void right_side_iter(CheckJob *, CheckContext *);
+
+static Continuation rightSideIterTable[] = {
+    right_side_iter<Node0>, right_side_iter<Node3>, right_side_iter<Node16>,
+    right_side_iter<Node48>, right_side_iter<Node256>};
+
 PRESERVE_NONE void begin(CheckJob *job, CheckContext *context) {
   job->lcp = longestCommonPrefix(job->begin.data(), job->end.data(),
                                  std::min(job->begin.size(), job->end.size()));
@@ -3388,9 +3299,47 @@ PRESERVE_NONE void done_common_prefix_iter(CheckJob *job,
   job->commonPrefixNode = job->n;
 
   if (job->lcp == int(job->begin.size())) {
-    job->setResult(checkRangeRightSide(job->n, job->end, job->lcp,
+    job->remaining = job->end;
-                                       job->readVersion, context->tls));
+    if (job->lcp == 0) {
-    MUSTTAIL return complete(job, context);
+      if (job->n->entryPresent &&
+          job->n->entry.pointVersion > job->readVersion) {
+        job->setResult(false);
+        MUSTTAIL return complete(job, context);
+      }
+
+      if (!checkMaxBetweenExclusive(job->n, -1, job->remaining[0],
+                                    job->readVersion, context->tls)) {
+        job->setResult(false);
+        MUSTTAIL return complete(job, context);
+      }
+    }
+
+    // This is a hack
+    --job->lcp;
+
+    auto c = getChild(job->n, job->remaining[0]);
+    Node *child = c;
+    if (child == nullptr) {
+      auto c = getChildGeq(job->n, job->remaining[0]);
+      if (c != nullptr) {
+        job->n = c;
+        job->continuation = check_point_read_state_machine::down_left_spine;
+        MUSTTAIL return job->continuation(job, context);
+      } else {
+        job->n = nextSibling(job->n);
+        if (job->n == nullptr) {
+          job->setResult(true);
+          MUSTTAIL return complete(job, context);
+        }
+        job->continuation = check_point_read_state_machine::down_left_spine;
+        MUSTTAIL return job->continuation(job, context);
+      }
+    }
+
+    job->n = child;
+    job->continuation = rightSideIterTable[c.getType()];
+    __builtin_prefetch(job->n);
+    MUSTTAIL return keepGoing(job, context);
   }
 
   // If this were not true we would have returned above
@@ -3541,10 +3490,32 @@ PRESERVE_NONE void left_side_iter(CheckJob *job, CheckContext *context) {
 
 PRESERVE_NONE void done_left_side_iter(CheckJob *job, CheckContext *context) {
 
-  job->setResult(checkRangeRightSide(job->commonPrefixNode, job->end,
+  job->n = job->commonPrefixNode;
-                                     job->lcp + 1, job->readVersion,
+  job->remaining = job->end;
-                                     context->tls));
+
-  MUSTTAIL return complete(job, context);
+  auto c = getChild(job->n, job->remaining[0]);
+  Node *child = c;
+  if (child == nullptr) {
+    auto c = getChildGeq(job->n, job->remaining[0]);
+    if (c != nullptr) {
+      job->n = c;
+      job->continuation = check_point_read_state_machine::down_left_spine;
+      MUSTTAIL return job->continuation(job, context);
+    } else {
+      job->n = nextSibling(job->n);
+      if (job->n == nullptr) {
+        job->setResult(true);
+        MUSTTAIL return complete(job, context);
+      }
+      job->continuation = check_point_read_state_machine::down_left_spine;
+      MUSTTAIL return job->continuation(job, context);
+    }
+  }
+
+  job->n = child;
+  job->continuation = rightSideIterTable[c.getType()];
+  __builtin_prefetch(job->n);
+  MUSTTAIL return keepGoing(job, context);
 }
 
 void left_side_down_left_spine(CheckJob *job, CheckContext *context) {
@@ -3561,6 +3532,102 @@ void left_side_down_left_spine(CheckJob *job, CheckContext *context) {
   MUSTTAIL return keepGoing(job, context);
 }
 
+// Return true if the max version among all keys that start with key[:prefixLen]
+// that are < key is <= readVersion
+template <class NodeT>
+PRESERVE_NONE void right_side_iter(CheckJob *job, CheckContext *context) {
+  assert(NodeT::kType == job->n->getType());
+  NodeT *n = static_cast<NodeT *>(job->n);
+
+  job->remaining = job->remaining.subspan(1, job->remaining.size() - 1);
+
+  if (n->partialKeyLen > 0) {
+    int commonLen = std::min<int>(n->partialKeyLen, job->remaining.size());
+    int i =
+        longestCommonPrefix(n->partialKey(), job->remaining.data(), commonLen);
+    if (i < commonLen) {
+      auto c = n->partialKey()[i] <=> job->remaining[i];
+      if (c > 0) {
+        job->continuation = check_point_read_state_machine::down_left_spine;
+        MUSTTAIL return job->continuation(job, context);
+      } else {
+        if ((n->parent != job->commonPrefixNode || i >= job->lcp) &&
+            n->entryPresent && n->entry.rangeVersion > job->readVersion) {
+          job->setResult(false);
+          MUSTTAIL return complete(job, context);
+        }
+        if ((n->parent != job->commonPrefixNode || i >= job->lcp) &&
+            maxVersion(n) > job->readVersion) {
+          job->setResult(false);
+          MUSTTAIL return complete(job, context);
+        }
+        job->n = nextSibling(job->n);
+        if (job->n == nullptr) {
+          job->setResult(true);
+          MUSTTAIL return complete(job, context);
+        }
+        job->continuation = check_point_read_state_machine::down_left_spine;
+        MUSTTAIL return job->continuation(job, context);
+      }
+    }
+    if (commonLen == n->partialKeyLen) {
+      // partial key matches
+      job->remaining =
+          job->remaining.subspan(commonLen, job->remaining.size() - commonLen);
+    } else if (n->partialKeyLen > int(job->remaining.size())) {
+      job->continuation = check_point_read_state_machine::down_left_spine;
+      MUSTTAIL return job->continuation(job, context);
+    }
+  }
+
+  ++context->tls->range_read_iterations_accum;
+
+  if (job->remaining.size() == 0) {
+    job->continuation = check_point_read_state_machine::down_left_spine;
+    MUSTTAIL return job->continuation(job, context);
+  }
+
+  if (n->entryPresent && (n->entry.pointVersion > job->readVersion ||
+                          n->entry.rangeVersion > job->readVersion)) {
+    job->setResult(false);
+    MUSTTAIL return complete(job, context);
+  }
+
+  if (!checkMaxBetweenExclusive(n, -1, job->remaining[0], job->readVersion,
+                                context->tls)) {
+    job->setResult(false);
+    MUSTTAIL return complete(job, context);
+  }
+
+  auto c = getChild(job->n, job->remaining[0]);
+  Node *child = c;
+  if (child == nullptr) {
+    auto c = getChildGeq(n, job->remaining[0]);
+    if (c != nullptr) {
+      job->n = c;
+      job->continuation = check_point_read_state_machine::down_left_spine;
+      MUSTTAIL return job->continuation(job, context);
+    } else {
+      if (n != job->commonPrefixNode && maxVersion(n) > job->readVersion) {
+        job->setResult(false);
+        MUSTTAIL return complete(job, context);
+      }
+      job->n = nextSibling(job->n);
+      if (job->n == nullptr) {
+        job->setResult(true);
+        MUSTTAIL return complete(job, context);
+      }
+      job->continuation = check_point_read_state_machine::down_left_spine;
+      MUSTTAIL return job->continuation(job, context);
+    }
+  }
+
+  job->n = child;
+  job->continuation = rightSideIterTable[c.getType()];
+  __builtin_prefetch(job->n);
+  MUSTTAIL return keepGoing(job, context);
+}
+
 } // namespace check_range_read_state_machine
 
 void CheckJob::init(const ConflictSet::ReadRange *read,