[include-fixer] Add fuzzy SymbolIndex, where identifier needn't match exactly.

Summary:
Add fuzzy SymbolIndex, where identifier needn't match exactly.

The purpose for this is global autocomplete in clangd. The query will be a
partial identifier up to the cursor, and the results will be suggestions.

It's in include-fixer because:

  - it handles SymbolInfos, actually SymbolIndex is exactly the right interface
  - it's a good harness for lit testing the fuzzy YAML index
  - (Laziness: we can't unit test clangd until reorganizing with a tool/ dir)

Other questionable choices:

  - FuzzySymbolIndex, which just refines the contract of SymbolIndex. This is
    an interface to allow extension to large monorepos (*cough*)
  - an always-true safety check that Identifier == Name is removed from
    SymbolIndexManager, as it's not true for fuzzy matching
  - exposing -db=fuzzyYaml from include-fixer is not a very useful feature, and
    a non-orthogonal ui (fuzziness vs data source). -db=fixed is similar though.

Reviewers: bkramer

Subscribers: cfe-commits, mgorny

Differential Revision: https://reviews.llvm.org/D30720

llvm-svn: 297630

clang-tools-extra/include-fixer/CMakeLists.txt

@@ -6,6 +6,7 @@ add_clang_library(clangIncludeFixer
   IncludeFixer.cpp
   IncludeFixerContext.cpp
   InMemorySymbolIndex.cpp
+  FuzzySymbolIndex.cpp
   SymbolIndexManager.cpp
   YamlSymbolIndex.cpp
 

clang-tools-extra/include-fixer/FuzzySymbolIndex.cpp

@@ -0,0 +1,143 @@
+//===--- FuzzySymbolIndex.cpp - Lookup symbols for autocomplete -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+#include "FuzzySymbolIndex.h"
+#include "llvm/Support/Regex.h"
+
+using clang::find_all_symbols::SymbolAndSignals;
+using llvm::StringRef;
+
+namespace clang {
+namespace include_fixer {
+namespace {
+
+class MemSymbolIndex : public FuzzySymbolIndex {
+public:
+  MemSymbolIndex(std::vector<SymbolAndSignals> Symbols) {
+    for (auto &Symbol : Symbols) {
+      auto Tokens = tokenize(Symbol.Symbol.getName());
+      this->Symbols.emplace_back(
+          StringRef(llvm::join(Tokens.begin(), Tokens.end(), " ")),
+          std::move(Symbol));
+    }
+  }
+
+  std::vector<SymbolAndSignals> search(StringRef Query) override {
+    auto Tokens = tokenize(Query);
+    llvm::Regex Pattern("^" + queryRegexp(Tokens));
+    std::vector<SymbolAndSignals> Results;
+    for (const Entry &E : Symbols)
+      if (Pattern.match(E.first))
+        Results.push_back(E.second);
+    return Results;
+  }
+
+private:
+  using Entry = std::pair<llvm::SmallString<32>, SymbolAndSignals>;
+  std::vector<Entry> Symbols;
+};
+
+// Helpers for tokenize state machine.
+enum TokenizeState {
+  EMPTY,      // No pending characters.
+  ONE_BIG,    // Read one uppercase letter, could be WORD or Word.
+  BIG_WORD,   // Reading an uppercase WORD.
+  SMALL_WORD, // Reading a lowercase word.
+  NUMBER      // Reading a number.
+};
+
+enum CharType { UPPER, LOWER, DIGIT, MISC };
+CharType classify(char c) {
+  if (isupper(c))
+    return UPPER;
+  if (islower(c))
+    return LOWER;
+  if (isdigit(c))
+    return DIGIT;
+  return MISC;
+}
+
+} // namespace
+
+std::vector<std::string> FuzzySymbolIndex::tokenize(StringRef Text) {
+  std::vector<std::string> Result;
+  // State describes the treatment of text from Start to I.
+  // Once text is Flush()ed into Result, we're done with it and advance Start.
+  TokenizeState State = EMPTY;
+  size_t Start = 0;
+  auto Flush = [&](size_t End) {
+    if (State != EMPTY) {
+      Result.push_back(Text.substr(Start, End - Start).lower());
+      State = EMPTY;
+    }
+    Start = End;
+  };
+  for (size_t I = 0; I < Text.size(); ++I) {
+    CharType Type = classify(Text[I]);
+    if (Type == MISC)
+      Flush(I);
+    else if (Type == LOWER)
+      switch (State) {
+      case BIG_WORD:
+        Flush(I - 1); // FOOBar: first token is FOO, not FOOB.
+        LLVM_FALLTHROUGH;
+      case ONE_BIG:
+        State = SMALL_WORD;
+        LLVM_FALLTHROUGH;
+      case SMALL_WORD:
+        break;
+      default:
+        Flush(I);
+        State = SMALL_WORD;
+      }
+    else if (Type == UPPER)
+      switch (State) {
+      case ONE_BIG:
+        State = BIG_WORD;
+        LLVM_FALLTHROUGH;
+      case BIG_WORD:
+        break;
+      default:
+        Flush(I);
+        State = ONE_BIG;
+      }
+    else if (Type == DIGIT && State != NUMBER) {
+      Flush(I);
+      State = NUMBER;
+    }
+  }
+  Flush(Text.size());
+  return Result;
+}
+
+std::string
+FuzzySymbolIndex::queryRegexp(const std::vector<std::string> &Tokens) {
+  std::string Result;
+  for (size_t I = 0; I < Tokens.size(); ++I) {
+    if (I)
+      Result.append("[[:alnum:]]* ");
+    for (size_t J = 0; J < Tokens[I].size(); ++J) {
+      if (J)
+        Result.append("([[:alnum:]]* )?");
+      Result.push_back(Tokens[I][J]);
+    }
+  }
+  return Result;
+}
+
+llvm::Expected<std::unique_ptr<FuzzySymbolIndex>>
+FuzzySymbolIndex::createFromYAML(StringRef FilePath) {
+  auto Buffer = llvm::MemoryBuffer::getFile(FilePath);
+  if (!Buffer)
+    return llvm::errorCodeToError(Buffer.getError());
+  return llvm::make_unique<MemSymbolIndex>(
+      find_all_symbols::ReadSymbolInfosFromYAML(Buffer.get()->getBuffer()));
+}
+
+} // namespace include_fixer
+} // namespace clang

clang-tools-extra/include-fixer/FuzzySymbolIndex.h

@@ -0,0 +1,55 @@
+//===--- FuzzySymbolIndex.h - Lookup symbols for autocomplete ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_INCLUDE_FIXER_FUZZY_SYMBOL_INDEX_H
+#define LLVM_CLANG_TOOLS_EXTRA_INCLUDE_FIXER_FUZZY_SYMBOL_INDEX_H
+
+#include "SymbolIndex.h"
+#include "find-all-symbols/SymbolInfo.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Error.h"
+#include <string>
+#include <vector>
+
+namespace clang {
+namespace include_fixer {
+
+// A FuzzySymbolIndex retrieves top-level symbols matching a query string.
+//
+// It refines the contract of SymbolIndex::search to do fuzzy matching:
+// - symbol names are tokenized: "unique ptr", "string ref".
+// - query must match prefixes of symbol tokens: [upt]
+// - if the query has multiple tokens, splits must match: [StR], not [STr].
+// Helpers for tokenization and regex matching are provided.
+//
+// Implementations may choose to truncate results, refuse short queries, etc.
+class FuzzySymbolIndex : public SymbolIndex {
+public:
+  // Loads the specified include-fixer database and returns an index serving it.
+  static llvm::Expected<std::unique_ptr<FuzzySymbolIndex>>
+  createFromYAML(llvm::StringRef File);
+
+  // Helpers for implementing indexes:
+
+  // Transforms a symbol name or query into a sequence of tokens.
+  // - URLHandlerCallback --> [url, handler, callback]
+  // - snake_case11 --> [snake, case, 11]
+  // - _WTF$ --> [wtf]
+  static std::vector<std::string> tokenize(llvm::StringRef Text);
+
+  // Transforms query tokens into an unanchored regexp to match symbol tokens.
+  // - [fe f] --> /f(\w* )?e\w* f/, matches [fee fie foe].
+  static std::string queryRegexp(const std::vector<std::string> &Tokens);
+};
+
+} // namespace include_fixer
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_INCLUDE_FIXER_FUZZY_SYMBOL_INDEX_H

clang-tools-extra/include-fixer/SymbolIndexManager.cpp

@@ -103,46 +103,44 @@ SymbolIndexManager::search(llvm::StringRef Identifier,
     for (auto &SymAndSig : Symbols) {
       const SymbolInfo &Symbol = SymAndSig.Symbol;
       // Match the identifier name without qualifier.
-      if (Symbol.getName() == Names.back()) {
-        bool IsMatched = true;
-        auto SymbolContext = Symbol.getContexts().begin();
-        auto IdentiferContext = Names.rbegin() + 1; // Skip identifier name.
-        // Match the remaining context names.
-        while (IdentiferContext != Names.rend() &&
-               SymbolContext != Symbol.getContexts().end()) {
-          if (SymbolContext->second == *IdentiferContext) {
-            ++IdentiferContext;
-            ++SymbolContext;
-          } else if (SymbolContext->first ==
-                     find_all_symbols::SymbolInfo::ContextType::EnumDecl) {
-            // Skip non-scoped enum context.
-            ++SymbolContext;
-          } else {
-            IsMatched = false;
-            break;
-          }
+      bool IsMatched = true;
+      auto SymbolContext = Symbol.getContexts().begin();
+      auto IdentiferContext = Names.rbegin() + 1; // Skip identifier name.
+      // Match the remaining context names.
+      while (IdentiferContext != Names.rend() &&
+             SymbolContext != Symbol.getContexts().end()) {
+        if (SymbolContext->second == *IdentiferContext) {
+          ++IdentiferContext;
+          ++SymbolContext;
+        } else if (SymbolContext->first ==
+                   find_all_symbols::SymbolInfo::ContextType::EnumDecl) {
+          // Skip non-scoped enum context.
+          ++SymbolContext;
+        } else {
+          IsMatched = false;
+          break;
         }
+      }
 
-        // If the name was qualified we only want to add results if we evaluated
-        // all contexts.
-        if (IsFullyQualified)
-          IsMatched &= (SymbolContext == Symbol.getContexts().end());
+      // If the name was qualified we only want to add results if we evaluated
+      // all contexts.
+      if (IsFullyQualified)
+        IsMatched &= (SymbolContext == Symbol.getContexts().end());
 
-        // FIXME: Support full match. At this point, we only find symbols in
-        // database which end with the same contexts with the identifier.
-        if (IsMatched && IdentiferContext == Names.rend()) {
-          // If we're in a situation where we took a prefix but the thing we
-          // found couldn't possibly have a nested member ignore it.
-          if (TookPrefix &&
-              (Symbol.getSymbolKind() == SymbolInfo::SymbolKind::Function ||
-               Symbol.getSymbolKind() == SymbolInfo::SymbolKind::Variable ||
-               Symbol.getSymbolKind() ==
-                   SymbolInfo::SymbolKind::EnumConstantDecl ||
-               Symbol.getSymbolKind() == SymbolInfo::SymbolKind::Macro))
-            continue;
+      // FIXME: Support full match. At this point, we only find symbols in
+      // database which end with the same contexts with the identifier.
+      if (IsMatched && IdentiferContext == Names.rend()) {
+        // If we're in a situation where we took a prefix but the thing we
+        // found couldn't possibly have a nested member ignore it.
+        if (TookPrefix &&
+            (Symbol.getSymbolKind() == SymbolInfo::SymbolKind::Function ||
+             Symbol.getSymbolKind() == SymbolInfo::SymbolKind::Variable ||
+             Symbol.getSymbolKind() ==
+                 SymbolInfo::SymbolKind::EnumConstantDecl ||
+             Symbol.getSymbolKind() == SymbolInfo::SymbolKind::Macro))
+          continue;
 
-          MatchedSymbols.push_back(std::move(SymAndSig));
-        }
+        MatchedSymbols.push_back(std::move(SymAndSig));
       }
     }
     Names.pop_back();
@@ -152,7 +150,7 @@ SymbolIndexManager::search(llvm::StringRef Identifier,
   rank(MatchedSymbols, FileName);
   // Strip signals, they are no longer needed.
   std::vector<SymbolInfo> Res;
-  for (const auto &SymAndSig : MatchedSymbols)
+  for (auto &SymAndSig : MatchedSymbols)
     Res.push_back(std::move(SymAndSig.Symbol));
   return Res;
 }

clang-tools-extra/include-fixer/tool/ClangIncludeFixer.cpp

@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "FuzzySymbolIndex.h"
 #include "InMemorySymbolIndex.h"
 #include "IncludeFixer.h"
 #include "IncludeFixerContext.h"
@@ -83,14 +84,16 @@ namespace {
 cl::OptionCategory IncludeFixerCategory("Tool options");
 
 enum DatabaseFormatTy {
-  fixed, ///< Hard-coded mapping.
-  yaml,  ///< Yaml database created by find-all-symbols.
+  fixed,     ///< Hard-coded mapping.
+  yaml,      ///< Yaml database created by find-all-symbols.
+  fuzzyYaml, ///< Yaml database with fuzzy-matched identifiers.
 };
 
 cl::opt<DatabaseFormatTy> DatabaseFormat(
     "db", cl::desc("Specify input format"),
     cl::values(clEnumVal(fixed, "Hard-coded mapping"),
-               clEnumVal(yaml, "Yaml database created by find-all-symbols")),
+               clEnumVal(yaml, "Yaml database created by find-all-symbols"),
+               clEnumVal(fuzzyYaml, "Yaml database, with fuzzy-matched names")),
     cl::init(yaml), cl::cat(IncludeFixerCategory));
 
 cl::opt<std::string> Input("input",
@@ -215,6 +218,21 @@ createSymbolIndexManager(StringRef FilePath) {
     SymbolIndexMgr->addSymbolIndex(std::move(CreateYamlIdx));
     break;
   }
+  case fuzzyYaml: {
+    // This mode is not very useful, because we don't correct the identifier.
+    // It's main purpose is to expose FuzzySymbolIndex to tests.
+    SymbolIndexMgr->addSymbolIndex(
+        []() -> std::unique_ptr<include_fixer::SymbolIndex> {
+          auto DB = include_fixer::FuzzySymbolIndex::createFromYAML(Input);
+          if (!DB) {
+            llvm::errs() << "Couldn't load fuzzy YAML db: "
+                         << llvm::toString(DB.takeError()) << '\n';
+            return nullptr;
+          }
+          return std::move(*DB);
+        });
+    break;
+  }
   }
   return SymbolIndexMgr;
 }

clang-tools-extra/test/include-fixer/Inputs/fake_yaml_db.yaml

@@ -10,6 +10,17 @@ Type:            Class
 Seen:            1
 Used:            0
 ---
+Name:           foo_bar
+Contexts:
+  - ContextType:     Namespace
+    ContextName:     a
+  - ContextType:     Namespace
+    ContextName:     b
+FilePath:        foobar.h
+Type:            Class
+Seen:            0
+Used:            0
+---
 Name:           bar
 Contexts:
   - ContextType:     Namespace

clang-tools-extra/test/include-fixer/yaml_fuzzy.cpp

@@ -0,0 +1,9 @@
+// RUN: sed -e 's#//.*$##' %s > %t.cpp
+// RUN: clang-include-fixer -db=fuzzyYaml -input=%p/Inputs/fake_yaml_db.yaml %t.cpp --
+// RUN: FileCheck %s -input-file=%t.cpp
+
+// include-fixer will add the include, but doesn't complete the symbol.
+// CHECK: #include "foobar.h"
+// CHECK: fba f;
+
+b::a::fba f;

clang-tools-extra/unittests/include-fixer/CMakeLists.txt

@@ -13,6 +13,7 @@ include_directories(${CLANG_SOURCE_DIR})
 
 add_extra_unittest(IncludeFixerTests
   IncludeFixerTest.cpp
+  FuzzySymbolIndexTests.cpp
   )
 
 target_link_libraries(IncludeFixerTests

clang-tools-extra/unittests/include-fixer/FuzzySymbolIndexTests.cpp

@@ -0,0 +1,61 @@
+//===-- FuzzySymbolIndexTests.cpp - Fuzzy symbol index unit tests ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "FuzzySymbolIndex.h"
+#include "gmock/gmock.h"
+#include "llvm/Support/Regex.h"
+#include "gtest/gtest.h"
+
+using testing::ElementsAre;
+using testing::Not;
+
+namespace clang {
+namespace include_fixer {
+namespace {
+
+TEST(FuzzySymbolIndexTest, Tokenize) {
+  EXPECT_THAT(FuzzySymbolIndex::tokenize("URLHandlerCallback"),
+              ElementsAre("url", "handler", "callback"));
+  EXPECT_THAT(FuzzySymbolIndex::tokenize("snake_case11"),
+              ElementsAre("snake", "case", "11"));
+  EXPECT_THAT(FuzzySymbolIndex::tokenize("__$42!!BOB\nbob"),
+              ElementsAre("42", "bob", "bob"));
+}
+
+MATCHER_P(MatchesSymbol, Identifier, "") {
+  llvm::Regex Pattern("^" + arg);
+  std::string err;
+  if (!Pattern.isValid(err)) {
+    *result_listener << "invalid regex: " << err;
+    return false;
+  }
+  auto Tokens = FuzzySymbolIndex::tokenize(Identifier);
+  std::string Target = llvm::join(Tokens.begin(), Tokens.end(), " ");
+  *result_listener << "matching against '" << Target << "'";
+  return llvm::Regex("^" + arg).match(Target);
+}
+
+TEST(FuzzySymbolIndexTest, QueryRegexp) {
+  auto QueryRegexp = [](const std::string &query) {
+    return FuzzySymbolIndex::queryRegexp(FuzzySymbolIndex::tokenize(query));
+  };
+  EXPECT_THAT(QueryRegexp("uhc"), MatchesSymbol("URLHandlerCallback"));
+  EXPECT_THAT(QueryRegexp("urhaca"), MatchesSymbol("URLHandlerCallback"));
+  EXPECT_THAT(QueryRegexp("uhcb"), Not(MatchesSymbol("URLHandlerCallback")))
+      << "Non-prefix";
+  EXPECT_THAT(QueryRegexp("uc"), Not(MatchesSymbol("URLHandlerCallback")))
+      << "Skip token";
+
+  EXPECT_THAT(QueryRegexp("uptr"), MatchesSymbol("unique_ptr"));
+  EXPECT_THAT(QueryRegexp("UniP"), MatchesSymbol("unique_ptr"));
+}
+
+} // namespace
+} // namespace include_fixer
+} // namespace clang