Speed up clang-tidy when profiling in on.

Summary:
Speed up clang-tidy when profiling in on.
It makes profiling runs twice as fast by reusing the time samples between the
different actions.
It also joins together the sampling of different matchers of the same check.

Reviewers: alexfh

Subscribers: klimek, cfe-commits

Differential Revision: http://reviews.llvm.org/D5972

llvm-svn: 220682

1 files changed, 31 insertions, 15 deletions

diff --git a/clang/lib/ASTMatchers/ASTMatchFinder.cpp b/clang/lib/ASTMatchers/ASTMatchFinder.cpp
index 612aaceaf23..27c02bbd2c9 100644
--- a/clang/lib/ASTMatchers/ASTMatchFinder.cpp
+++ b/clang/lib/ASTMatchers/ASTMatchFinder.cpp
@@ -307,18 +307,20 @@ public:
 
   void onStartOfTranslationUnit() {
     const bool EnableCheckProfiling = Options.CheckProfiling.hasValue();
+    TimeBucketRegion Timer;
     for (MatchCallback *MC : Matchers->AllCallbacks) {
-      TimeRegion Timer(EnableCheckProfiling ? &TimeByBucket[MC->getID()]
-                                            : nullptr);
+      if (EnableCheckProfiling)
+        Timer.setBucket(&TimeByBucket[MC->getID()]);
       MC->onStartOfTranslationUnit();
     }
   }
 
   void onEndOfTranslationUnit() {
     const bool EnableCheckProfiling = Options.CheckProfiling.hasValue();
+    TimeBucketRegion Timer;
     for (MatchCallback *MC : Matchers->AllCallbacks) {
-      TimeRegion Timer(EnableCheckProfiling ? &TimeByBucket[MC->getID()]
-                                            : nullptr);
+      if (EnableCheckProfiling)
+        Timer.setBucket(&TimeByBucket[MC->getID()]);
       MC->onEndOfTranslationUnit();
     }
   }
@@ -489,19 +491,32 @@ public:
   bool shouldUseDataRecursionFor(clang::Stmt *S) const { return false; }
 
 private:
-  class TimeRegion {
+  class TimeBucketRegion {
   public:
-    TimeRegion(llvm::TimeRecord *Record) : Record(Record) {
-      if (Record)
-        *Record -= llvm::TimeRecord::getCurrentTime(true);
-    }
-    ~TimeRegion() {
-      if (Record)
-        *Record += llvm::TimeRecord::getCurrentTime(false);
+    TimeBucketRegion() : Bucket(nullptr) {}
+    ~TimeBucketRegion() { setBucket(nullptr); }
+
+    /// \brief Start timing for \p NewBucket.
+    ///
+    /// If there was a bucket already set, it will finish the timing for that
+    /// other bucket.
+    /// \p NewBucket will be timed until the next call to \c setBucket() or
+    /// until the \c TimeBucketRegion is destroyed.
+    /// If \p NewBucket is the same as the currently timed bucket, this call
+    /// does nothing.
+    void setBucket(llvm::TimeRecord *NewBucket) {
+      if (Bucket != NewBucket) {
+        auto Now = llvm::TimeRecord::getCurrentTime(true);
+        if (Bucket)
+          *Bucket += Now;
+        if (NewBucket)
+          *NewBucket -= Now;
+        Bucket = NewBucket;
+      }
     }
 
   private:
-    llvm::TimeRecord *Record;
+    llvm::TimeRecord *Bucket;
   };
 
   /// \brief Runs all the \p Matchers on \p Node.
@@ -510,9 +525,10 @@ private:
   template <typename T, typename MC>
   void matchImpl(const T &Node, const MC &Matchers) {
     const bool EnableCheckProfiling = Options.CheckProfiling.hasValue();
+    TimeBucketRegion Timer;
     for (const auto &MP : Matchers) {
-      TimeRegion Timer(EnableCheckProfiling ? &TimeByBucket[MP.second->getID()]
-                                            : nullptr);
+      if (EnableCheckProfiling)
+        Timer.setBucket(&TimeByBucket[MP.second->getID()]);
       BoundNodesTreeBuilder Builder;
       if (MP.first.matches(Node, this, &Builder)) {
         MatchVisitor Visitor(ActiveASTContext, MP.second);