[DebugCounters] Keep track of total counts

This patch makes debug counters keep track of the total number of times
we've called `shouldExecute` for each counter, so it's easier to build
automated tooling on top of these.

A patch to print these counts is coming soon.

Patch by Zhizhou Yang!

Differential Revision: https://reviews.llvm.org/D49560

llvm-svn: 337748

5 files changed, 81 insertions, 35 deletions

diff --git a/llvm/include/llvm/Support/DebugCounter.h b/llvm/include/llvm/Support/DebugCounter.h
index c3bed9d3ce2..250fc6bb1f5 100644
--- a/llvm/include/llvm/Support/DebugCounter.h
+++ b/llvm/include/llvm/Support/DebugCounter.h
@@ -77,23 +77,19 @@ public:
     auto &Us = instance();
     auto Result = Us.Counters.find(CounterName);
     if (Result != Us.Counters.end()) {
-      auto &CounterPair = Result->second;
-      // We only execute while the skip (first) is zero and the count (second)
-      // is non-zero.
+      auto &CounterInfo = Result->second;
+      ++CounterInfo.Count;
+
+      // We only execute while the Skip is not smaller than Count,
+      // and the StopAfter + Skip is larger than Count.
       // Negative counters always execute.
-      if (CounterPair.first < 0)
+      if (CounterInfo.Skip < 0)
         return true;
-      if (CounterPair.first != 0) {
-        --CounterPair.first;
+      if (CounterInfo.Skip >= CounterInfo.Count)
         return false;
-      }
-      if (CounterPair.second < 0)
-        return true;
-      if (CounterPair.second != 0) {
-        --CounterPair.second;
+      if (CounterInfo.StopAfter < 0)
         return true;
-      }
-      return false;
+      return CounterInfo.StopAfter + CounterInfo.Skip >= CounterInfo.Count;
     }
     // Didn't find the counter, should we warn?
     return true;
@@ -104,21 +100,21 @@ public:
   // the command line).  This will return true even if those values are
   // currently in a state where the counter will always execute.
   static bool isCounterSet(unsigned ID) {
-    return instance().Counters.count(ID);
+    return instance().Counters[ID].IsSet;
   }
 
-  // Return the skip and count for a counter. This only works for set counters.
-  static std::pair<int, int> getCounterValue(unsigned ID) {
+  // Return the Count for a counter. This only works for set counters.
+  static int64_t getCounterValue(unsigned ID) {
     auto &Us = instance();
     auto Result = Us.Counters.find(ID);
     assert(Result != Us.Counters.end() && "Asking about a non-set counter");
-    return Result->second;
+    return Result->second.Count;
   }
 
-  // Set a registered counter to a given value.
-  static void setCounterValue(unsigned ID, const std::pair<int, int> &Val) {
+  // Set a registered counter to a given Count value.
+  static void setCounterValue(unsigned ID, int64_t Count) {
     auto &Us = instance();
-    Us.Counters[ID] = Val;
+    Us.Counters[ID].Count = Count;
   }
 
   // Dump or print the current counter set into llvm::dbgs().
@@ -136,7 +132,7 @@ public:
 
   // Return the name and description of the counter with the given ID.
   std::pair<std::string, std::string> getCounterInfo(unsigned ID) const {
-    return std::make_pair(RegisteredCounters[ID], CounterDesc.lookup(ID));
+    return std::make_pair(RegisteredCounters[ID], Counters.lookup(ID).Desc);
   }
 
   // Iterate through the registered counters
@@ -149,11 +145,19 @@ public:
 private:
   unsigned addCounter(const std::string &Name, const std::string &Desc) {
     unsigned Result = RegisteredCounters.insert(Name);
-    CounterDesc[Result] = Desc;
+    Counters[Result] = {};
+    Counters[Result].Desc = Desc;
     return Result;
   }
-  DenseMap<unsigned, std::pair<long, long>> Counters;
-  DenseMap<unsigned, std::string> CounterDesc;
+  // Struct to store counter info.
+  struct CounterInfo {
+    int64_t Count = 0;
+    int64_t Skip = 0;
+    int64_t StopAfter = -1;
+    bool IsSet = false;
+    std::string Desc;
+  };
+  DenseMap<unsigned, CounterInfo> Counters;
   CounterVector RegisteredCounters;
 };
 
diff --git a/llvm/lib/Support/DebugCounter.cpp b/llvm/lib/Support/DebugCounter.cpp
index 4a439746541..5a9cecfc56d 100644
--- a/llvm/lib/Support/DebugCounter.cpp
+++ b/llvm/lib/Support/DebugCounter.cpp
@@ -66,7 +66,7 @@ void DebugCounter::push_back(const std::string &Val) {
   }
   // Now we have counter=value.
   // First, process value.
-  long CounterVal;
+  int64_t CounterVal;
   if (CounterPair.second.getAsInteger(0, CounterVal)) {
     errs() << "DebugCounter Error: " << CounterPair.second
            << " is not a number\n";
@@ -76,26 +76,24 @@ void DebugCounter::push_back(const std::string &Val) {
   // add it to the counter values.
   if (CounterPair.first.endswith("-skip")) {
     auto CounterName = CounterPair.first.drop_back(5);
-    unsigned CounterID = RegisteredCounters.idFor(CounterName);
+    unsigned CounterID = getCounterId(CounterName);
     if (!CounterID) {
       errs() << "DebugCounter Error: " << CounterName
              << " is not a registered counter\n";
       return;
     }
-
-    auto Res = Counters.insert({CounterID, {0, -1}});
-    Res.first->second.first = CounterVal;
+    Counters[CounterID].Skip = CounterVal;
+    Counters[CounterID].IsSet = true;
   } else if (CounterPair.first.endswith("-count")) {
     auto CounterName = CounterPair.first.drop_back(6);
-    unsigned CounterID = RegisteredCounters.idFor(CounterName);
+    unsigned CounterID = getCounterId(CounterName);
     if (!CounterID) {
       errs() << "DebugCounter Error: " << CounterName
              << " is not a registered counter\n";
       return;
     }
-
-    auto Res = Counters.insert({CounterID, {0, -1}});
-    Res.first->second.second = CounterVal;
+    Counters[CounterID].StopAfter = CounterVal;
+    Counters[CounterID].IsSet = true;
   } else {
     errs() << "DebugCounter Error: " << CounterPair.first
            << " does not end with -skip or -count\n";
@@ -106,7 +104,8 @@ void DebugCounter::print(raw_ostream &OS) const {
   OS << "Counters and values:\n";
   for (const auto &KV : Counters)
     OS << left_justify(RegisteredCounters[KV.first], 32) << ": {"
-       << KV.second.first << "," << KV.second.second << "}\n";
+       << KV.second.Count << "," << KV.second.Skip << ","
+       << KV.second.StopAfter << "}\n";
 }
 
 LLVM_DUMP_METHOD void DebugCounter::dump() const {
diff --git a/llvm/lib/Transforms/Scalar/NewGVN.cpp b/llvm/lib/Transforms/Scalar/NewGVN.cpp
index 994d0d212cf..2eb887c986b 100644
--- a/llvm/lib/Transforms/Scalar/NewGVN.cpp
+++ b/llvm/lib/Transforms/Scalar/NewGVN.cpp
@@ -861,7 +861,7 @@ private:
 
   // Debug counter info.  When verifying, we have to reset the value numbering
   // debug counter to the same state it started in to get the same results.
-  std::pair<int, int> StartingVNCounter;
+  int64_t StartingVNCounter;
 };
 
 } // end anonymous namespace
diff --git a/llvm/unittests/Support/CMakeLists.txt b/llvm/unittests/Support/CMakeLists.txt
index 266a389b8b7..4e08d7df7ad 100644
--- a/llvm/unittests/Support/CMakeLists.txt
+++ b/llvm/unittests/Support/CMakeLists.txt
@@ -20,6 +20,7 @@ add_llvm_unittest(SupportTests
   ConvertUTFTest.cpp
   DataExtractorTest.cpp
   DebugTest.cpp
+  DebugCounterTest.cpp
   DJBTest.cpp
   EndianStreamTest.cpp
   EndianTest.cpp
diff --git a/llvm/unittests/Support/DebugCounterTest.cpp b/llvm/unittests/Support/DebugCounterTest.cpp
new file mode 100644
index 00000000000..f3c2817a22e
--- /dev/null
+++ b/llvm/unittests/Support/DebugCounterTest.cpp
@@ -0,0 +1,42 @@
+//===- llvm/unittest/Support/DebugCounterTest.cpp -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/DebugCounter.h"
+#include "gtest/gtest.h"
+
+#include <string>
+using namespace llvm;
+
+#ifndef NDEBUG
+DEBUG_COUNTER(TestCounter, "test-counter",
+              "Counter used for unit test");
+
+TEST(DebugCounterTest, CounterCheck) {
+  EXPECT_FALSE(DebugCounter::isCounterSet(TestCounter));
+
+  auto DC = &DebugCounter::instance();
+  DC->push_back("test-counter-skip=1");
+  DC->push_back("test-counter-count=3");
+
+  EXPECT_TRUE(DebugCounter::isCounterSet(TestCounter));
+
+  EXPECT_EQ(0, DebugCounter::getCounterValue(TestCounter));
+  EXPECT_FALSE(DebugCounter::shouldExecute(TestCounter));
+
+  EXPECT_EQ(1, DebugCounter::getCounterValue(TestCounter));
+  EXPECT_TRUE(DebugCounter::shouldExecute(TestCounter));
+
+  DebugCounter::setCounterValue(TestCounter, 3);
+  EXPECT_TRUE(DebugCounter::shouldExecute(TestCounter));
+  EXPECT_FALSE(DebugCounter::shouldExecute(TestCounter));
+
+  DebugCounter::setCounterValue(TestCounter, 100);
+  EXPECT_FALSE(DebugCounter::shouldExecute(TestCounter));
+}
+#endif