Merge pull request #1199 from hzeller/20220217-store-stringpiece-in-s…

…ignature

Store string_view in Signature() array, not std::string.

verilog/tools/kythe/BUILD

@@ -49,8 +49,8 @@ cc_library(
         ":kythe_facts",
         "//common/util:auto_pop_stack",
         "//common/util:iterator_range",
-        "@com_google_absl//absl/strings",
         "@com_google_absl//absl/container:node_hash_map",
+        "@com_google_absl//absl/strings",
     ],
 )
 
@@ -94,6 +94,7 @@ cc_library(
         "//verilog/analysis:verilog_project",
         "@com_google_absl//absl/container:btree",
         "@com_google_absl//absl/container:flat_hash_set",
+        "@com_google_absl//absl/container:node_hash_set",
         "@com_google_absl//absl/memory",
         "@com_google_absl//absl/strings",
     ],

verilog/tools/kythe/kythe_facts.h

@@ -30,12 +30,11 @@ inline constexpr absl::string_view kEmptyKytheLanguage = "";
 // Unique identifier for Kythe facts.
 class Signature {
  public:
-  explicit Signature(absl::string_view name = "")
-      : names_({std::string(name)}) {}
+  explicit Signature(absl::string_view name = "") : names_({name}) {}
 
   Signature(const Signature& parent, absl::string_view name)
       : names_(parent.Names()) {
-    names_.push_back(std::string(name));
+    names_.push_back(name);
   }
 
   bool operator==(const Signature& other) const {
@@ -52,7 +51,7 @@ class Signature {
   // Returns the signature concatenated as a string in base 64.
   std::string ToBase64() const;
 
-  const std::vector<std::string>& Names() const { return names_; }
+  const std::vector<absl::string_view>& Names() const { return names_; }
 
  private:
   // List that uniquely determines this signature and differentiates it from any
@@ -65,7 +64,7 @@ class Signature {
   //
   // for "m" ==> ["m"]
   // for "x" ==> ["m", "x"]
-  std::vector<std::string> names_;
+  std::vector<absl::string_view> names_;
 };
 template <typename H>
 H AbslHashValue(H state, const Signature& v) {

verilog/tools/kythe/kythe_facts_extractor.cc

@@ -24,6 +24,7 @@
 
 #include "absl/container/btree_map.h"
 #include "absl/container/flat_hash_set.h"
+#include "absl/container/node_hash_set.h"
 #include "absl/memory/memory.h"
 #include "absl/strings/escaping.h"
 #include "absl/strings/str_cat.h"
@@ -279,6 +280,13 @@ class KytheFactsExtractor {
 
   // Contains resulting kythe facts and edges to output.
   KytheIndexingData kythe_data_;
+
+  // Location signature backing store.
+  // Inside signatures, we record locations as string_views,
+  // this is the backing store for assembled strings as
+  // location markers such as "@123:456"
+  // Needs to be a node_hash_set to provide value stability.
+  absl::node_hash_set<std::string> signature_locations_;
 };
 
 void StreamKytheFactsEntries(KytheOutput* kythe_output,
@@ -1266,10 +1274,11 @@ VName KytheFactsExtractor::CreateAnchor(const Anchor& anchor) {
   const int start_location =
       std::distance(source_text.begin(), anchor.Text().begin());
   const int end_location = start_location + anchor.Text().length();
+  const auto [location_str, _] = signature_locations_.emplace(
+      absl::StrCat("@", start_location, ":", end_location));
   const VName anchor_vname = {.path = FilePath(),
                               .root = "",
-                              .signature = Signature(absl::StrCat(
-                                  "@", start_location, ":", end_location)),
+                              .signature = Signature(*location_str),
                               .corpus = Corpus()};
 
   CreateFact(anchor_vname, kFactNodeKind, kNodeAnchor);

verilog/tools/kythe/scope_resolver.h

@@ -54,7 +54,7 @@ class Scope {
   // Appends the member of the given scope to the current scope.
   void AppendScope(const Scope& scope);
 
-  using MemberMap = absl::node_hash_map<std::string, ScopeMemberItem>;
+  using MemberMap = absl::node_hash_map<absl::string_view, ScopeMemberItem>;
   const MemberMap& Members() const { return members_; }
   const Signature& GetSignature() const { return signature_; }