Honor lengths in merged named-data keys (#22977)

extension/named_data_map/merged_data_map.cpp

@@ -37,7 +37,7 @@ namespace ET_MERGED_DATA_MAP_NAMESPACE {
       "No non-empty named data maps provided to merge");
 
   // Check for duplicate keys.
-  std::unordered_map<std::string, uint32_t> key_to_map_index;
+  KeyToMapIndex key_to_map_index;
   for (const uint32_t i : c10::irange(valid_data_maps.size())) {
     const auto cur_map = valid_data_maps[i];
     uint32_t num_keys = cur_map->get_num_keys().get();
@@ -47,7 +47,8 @@ namespace ET_MERGED_DATA_MAP_NAMESPACE {
       ET_CHECK_OR_RETURN_ERROR(
           inserted,
           InvalidArgument,
-          "Duplicate key %s in named data maps at index %u and %" PRIu32,
+          "Duplicate key %s in named data maps at index %" PRIu32
+          " and %" PRIu32,
           cur_key,
           it->second,
           i);
@@ -58,19 +59,27 @@ namespace ET_MERGED_DATA_MAP_NAMESPACE {
 
 ET_NODISCARD Result<const TensorLayout> MergedDataMap::get_tensor_layout(
     string_view key) const {
-  const auto it = key_to_map_index_.find(key.data());
+  const auto it = key_to_map_index_.find(key);
   if (it == key_to_map_index_.end()) {
-    ET_LOG(Debug, "Key %s not found in named data maps.", key.data());
+    ET_LOG(
+        Debug,
+        "Key %.*s not found in named data maps.",
+        static_cast<int>(key.size()),
+        key.data());
     return Error::NotFound;
   }
   return named_data_maps_.at(it->second)->get_tensor_layout(key);
 }
 
 ET_NODISCARD
 Result<FreeableBuffer> MergedDataMap::get_data(string_view key) const {
-  const auto it = key_to_map_index_.find(key.data());
+  const auto it = key_to_map_index_.find(key);
   if (it == key_to_map_index_.end()) {
-    ET_LOG(Debug, "Key %s not found in named data maps.", key.data());
+    ET_LOG(
+        Debug,
+        "Key %.*s not found in named data maps.",
+        static_cast<int>(key.size()),
+        key.data());
     return Error::NotFound;
   }
   return named_data_maps_.at(it->second)->get_data(key);
@@ -80,11 +89,12 @@ ET_NODISCARD Error MergedDataMap::load_data_into(
     string_view key,
     void* buffer,
     size_t size) const {
-  const auto it = key_to_map_index_.find(key.data());
+  const auto it = key_to_map_index_.find(key);
   ET_CHECK_OR_RETURN_ERROR(
       it != key_to_map_index_.end(),
       NotFound,
-      "Key %s not found in named data maps",
+      "Key %.*s not found in named data maps",
+      static_cast<int>(key.size()),
       key.data());
   return named_data_maps_.at(it->second)->load_data_into(key, buffer, size);
 }
@@ -98,7 +108,7 @@ ET_NODISCARD Result<const char*> MergedDataMap::get_key(uint32_t index) const {
   ET_CHECK_OR_RETURN_ERROR(
       index < total_num_keys,
       InvalidArgument,
-      "Index %u out of range of size %u",
+      "Index %" PRIu32 " out of range of size %" PRIu32,
       index,
       total_num_keys);
   for (auto i : c10::irange(named_data_maps_.size())) {

extension/named_data_map/merged_data_map.h

@@ -10,6 +10,7 @@
 
 #include <executorch/runtime/core/named_data_map.h>
 
+#include <string_view>
 #include <unordered_map>
 #include <vector>
 
@@ -92,10 +93,12 @@ class MergedDataMap final
   ~MergedDataMap() override = default;
 
  private:
+  using KeyToMapIndex = std::unordered_map<std::string_view, uint32_t>;
+
   MergedDataMap(
       std::vector<const executorch::ET_RUNTIME_NAMESPACE::NamedDataMap*>
           named_data_maps,
-      std::unordered_map<std::string, uint32_t> key_to_map_index)
+      KeyToMapIndex key_to_map_index)
       : named_data_maps_(std::move(named_data_maps)),
         key_to_map_index_(std::move(key_to_map_index)) {}
 
@@ -107,8 +110,8 @@ class MergedDataMap final
   std::vector<const executorch::ET_RUNTIME_NAMESPACE::NamedDataMap*>
       named_data_maps_;
 
-  // Map from key to index in the named_data_maps_ vector.
-  std::unordered_map<std::string, uint32_t> key_to_map_index_;
+  // Keys alias stable storage owned by the wrapped, longer-lived data maps.
+  KeyToMapIndex key_to_map_index_;
 };
 
 } // namespace ET_MERGED_DATA_MAP_NAMESPACE

extension/named_data_map/test/merged_data_map_test.cpp

@@ -16,7 +16,9 @@
 
 #include <gtest/gtest.h>
 
+#include <cstring>
 #include <memory>
+#include <string>
 #include <unordered_map>
 #include <vector>
 
@@ -120,8 +122,7 @@ void compare_ndm_api_calls(
     EXPECT_EQ(merged_load_into, Error::Ok);
     for (auto j : c10::irange(ndm_meta.nbytes())) {
       EXPECT_EQ(
-          ((uint8_t*)merged_buffer.get())[j],
-          ((uint8_t*)merged_buffer.get())[j]);
+          ((uint8_t*)ndm_buffer.get())[j], ((uint8_t*)merged_buffer.get())[j]);
     }
   }
 }
@@ -171,3 +172,25 @@ TEST_F(MergedDataMapTest, CheckDataMapContents) {
   compare_ndm_api_calls(data_maps_["addmul"].get(), &merged_map.get());
   compare_ndm_api_calls(data_maps_["linear"].get(), &merged_map.get());
 }
+
+TEST_F(MergedDataMapTest, LookupUsesStringViewLength) {
+  std::vector<const NamedDataMap*> ndms = {data_maps_["addmul"].get()};
+  Result<MergedDataMap> merged_map =
+      MergedDataMap::load(Span<const NamedDataMap*>(ndms.data(), ndms.size()));
+  ASSERT_EQ(merged_map.error(), Error::Ok);
+
+  const char* key = data_maps_["addmul"]->get_key(0).get();
+  const size_t key_size = std::strlen(key);
+  const std::string storage = std::string(key) + ".not-part-of-key";
+  const std::string_view bounded_key(storage.data(), key_size);
+
+  EXPECT_EQ(merged_map->get_data(bounded_key).error(), Error::Ok);
+  EXPECT_EQ(merged_map->get_tensor_layout(bounded_key).error(), Error::Ok);
+  const auto layout = merged_map->get_tensor_layout(bounded_key);
+  ASSERT_EQ(layout.error(), Error::Ok);
+  const size_t data_size = layout->nbytes();
+  auto buffer = std::make_unique<uint8_t[]>(data_size);
+  EXPECT_EQ(
+      merged_map->load_data_into(bounded_key, buffer.get(), data_size),
+      Error::Ok);
+}