Speed up hasName() matcher.

Summary:
Speed up hasName() matcher by skipping the expensive generation of the
fully qualified name unless we need it.
In the common case of matching an unqualified name, we don't need to
generate the full name. We might not even need to copy any string at
all.
This change speeds up our clang-tidy benchmark by ~10%

Reviewers: klimek

Subscribers: klimek, cfe-commits

Differential Revision: http://reviews.llvm.org/D5776

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@219792 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/ASTMatchers/ASTMatchers.h b/include/clang/ASTMatchers/ASTMatchers.h
index 281976648394290c217ecda7a1a6d05e2c96d78f..335e91a46765a4e2f5427b07544f41ee0a1d8994 100644 (file)
--- a/include/clang/ASTMatchers/ASTMatchers.h
+++ b/include/clang/ASTMatchers/ASTMatchers.h
@@ -1591,16 +1591,8 @@ inline internal::Matcher<Stmt> sizeOfExpr(
 /// \code
 ///   namespace a { namespace b { class X; } }
 /// \endcode
-AST_MATCHER_P(NamedDecl, hasName, std::string, Name) {
-  assert(!Name.empty());
-  const std::string FullNameString = "::" + Node.getQualifiedNameAsString();
-  const StringRef FullName = FullNameString;
-  const StringRef Pattern = Name;
-  if (Pattern.startswith("::")) {
-    return FullName == Pattern;
-  } else {
-    return FullName.endswith(("::" + Pattern).str());
-  }
+inline internal::Matcher<NamedDecl> hasName(StringRef Name) {
+  return internal::Matcher<NamedDecl>(new internal::HasNameMatcher(Name));
 }
 
 /// \brief Matches NamedDecl nodes whose fully qualified names contain

diff --git a/include/clang/ASTMatchers/ASTMatchersInternal.h b/include/clang/ASTMatchers/ASTMatchersInternal.h
index 5c991e2a3b80083202c3ba188a847c31f921b271..d250a8abca25f6d1254b53ab9394b12c1728e7ee 100644 (file)
--- a/include/clang/ASTMatchers/ASTMatchersInternal.h
+++ b/include/clang/ASTMatchers/ASTMatchersInternal.h
@@ -574,6 +574,33 @@ private:
   std::string Name;
 };
 
+/// \brief Matches named declarations with a specific name.
+///
+/// See \c hasName() in ASTMatchers.h for details.
+class HasNameMatcher : public SingleNodeMatcherInterface<NamedDecl> {
+ public:
+  explicit HasNameMatcher(StringRef Name);
+
+  bool matchesNode(const NamedDecl &Node) const override;
+
+ private:
+  /// \brief Unqualified match routine.
+  ///
+  /// It is much faster than the full match, but it only works for unqualified
+  /// matches.
+  bool matchesNodeUnqualified(const NamedDecl &Node) const;
+
+  /// \brief Full match routine
+  ///
+  /// It generates the fully qualified name of the declaration (which is
+  /// expensive) before trying to match.
+  /// It is slower but simple and works on all cases.
+  bool matchesNodeFull(const NamedDecl &Node) const;
+
+  const bool UseUnqualifiedMatch;
+  const std::string Name;
+};
+
 /// \brief Matches declarations for QualType and CallExpr.
 ///
 /// Type argument DeclMatcherT is required by PolymorphicMatcherWithParam1 but

diff --git a/lib/ASTMatchers/ASTMatchersInternal.cpp b/lib/ASTMatchers/ASTMatchersInternal.cpp
index 9d77cb65767f75b1b9ffb103c1bfca2b70d5aae7..b5d4b52ade22fa91f695bd4d396cb5173dafc8e9 100644 (file)
--- a/lib/ASTMatchers/ASTMatchersInternal.cpp
+++ b/lib/ASTMatchers/ASTMatchersInternal.cpp
@@ -13,6 +13,7 @@
 
 #include "clang/ASTMatchers/ASTMatchers.h"
 #include "clang/ASTMatchers/ASTMatchersInternal.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/Support/ManagedStatic.h"
 
 namespace clang {
@@ -221,6 +222,51 @@ bool AnyOfVariadicOperator(const ast_type_traits::DynTypedNode DynNode,
   return false;
 }
 
+HasNameMatcher::HasNameMatcher(StringRef NameRef)
+    : UseUnqualifiedMatch(NameRef.find("::") == NameRef.npos), Name(NameRef) {
+  assert(!Name.empty());
+}
+
+bool HasNameMatcher::matchesNodeUnqualified(const NamedDecl &Node) const {
+  assert(UseUnqualifiedMatch);
+  if (Node.getIdentifier()) {
+    // Simple name.
+    return Name == Node.getName();
+  } else if (Node.getDeclName()) {
+    // Name needs to be constructed.
+    llvm::SmallString<128> NodeName;
+    llvm::raw_svector_ostream OS(NodeName);
+    Node.printName(OS);
+    return Name == OS.str();
+  } else {
+    return false;
+  }
+}
+
+bool HasNameMatcher::matchesNodeFull(const NamedDecl &Node) const {
+  llvm::SmallString<128> NodeName = StringRef("::");
+  llvm::raw_svector_ostream OS(NodeName);
+  Node.printQualifiedName(OS);
+  const StringRef FullName = OS.str();
+  const StringRef Pattern = Name;
+  if (Pattern.startswith("::")) {
+    return FullName == Pattern;
+  } else {
+    return FullName.endswith(("::" + Pattern).str());
+  }
+}
+
+bool HasNameMatcher::matchesNode(const NamedDecl &Node) const {
+  // FIXME: There is still room for improvement, but it would require copying a
+  // lot of the logic from NamedDecl::printQualifiedName(). The benchmarks do
+  // not show like that extra complexity is needed right now.
+  if (UseUnqualifiedMatch) {
+    assert(matchesNodeUnqualified(Node) == matchesNodeFull(Node));
+    return matchesNodeUnqualified(Node);
+  }
+  return matchesNodeFull(Node);
+}
+
 } // end namespace internal
 } // end namespace ast_matchers
 } // end namespace clang