Subzero: Rewrite the pass timing infrastructure.

src/IceGlobalContext.cpp

Index: src/IceGlobalContext.cpp
diff --git a/src/IceGlobalContext.cpp b/src/IceGlobalContext.cpp
index 319e18a9d6a3c6ecac74d7bc3454b44eed6bbaad..14d51e717afa2c47b1927d1edff772108047909e 100644
--- a/src/IceGlobalContext.cpp
+++ b/src/IceGlobalContext.cpp
@@ -115,6 +115,93 @@ public:
   UndefPool Undefs;
 };
 
+class TimerStack {
+  TimerStack(const TimerStack &) LLVM_DELETED_FUNCTION;
+  TimerStack &operator=(const TimerStack &) LLVM_DELETED_FUNCTION;
+
+public:
+  TimerStack(const IceString &TopLevelName)
+      : FirstTimestamp(timestamp()), LastTimestamp(FirstTimestamp) {
+    push(TopLevelName);
+  }
+  void push(const IceString &Name) {
+    update();
+    Stack.push_back(Name);
+    // Construct the new node's recursive name by appending .Name to
+    // the previous top-of-stack's recursive name.
+    IceString Prefix = "";
+    if (!FullNames.empty())
+      Prefix = FullNames.back() + ".";
+    FullNames.push_back(Prefix + Name);
+  }
+  void pop(const IceString &Name) {
+    update();
+    assert(!Stack.empty());
+    assert(Stack.back() == Name);
+    Stack.pop_back();
+    FullNames.pop_back();
+  }
+  void dump(Ostream &Str);
+
+private:
+  typedef std::map<IceString, double> MapType;
+  void update();
+  void dumpHelper(Ostream &Str, const MapType &Map, double TotalTime);
+  static double timestamp() {
+    // TODO: Implement in terms of std::chrono for C++11.
+    return llvm::TimeRecord::getCurrentTime(false).getWallTime();
+  }
+  const double FirstTimestamp;
+  volatile double LastTimestamp;
+  std::vector<IceString> Stack;
+  std::vector<IceString> FullNames;
+  MapType RecursiveTime;
+  MapType LeafTime;
+};
+
+void TimerStack::update() {
+  // Whenever the stack is about to change, we grab the time delta
+  // since the last change and add it to all active recursive elements
+  // and to the non-recursive element for the top of the stack.
+  double Current = timestamp();
+  double Delta = Current - LastTimestamp;
+  LastTimestamp = Current;
+  for (size_t i = 0; i < FullNames.size(); ++i) {
+    RecursiveTime[FullNames[i]] += Delta;
+  }
+  if (!Stack.empty()) {
+    LeafTime[Stack.back()] += Delta;
+  }
+}
+
+void TimerStack::dumpHelper(Ostream &Str, const MapType &Map,
+                            double TotalTime) {
+  // Dump the items in reverse order of their time contribution.
+  typedef std::multimap<double, IceString> RMapType;
+  RMapType MultiMap;
+  for (MapType::const_iterator I = Map.begin(), E = Map.end(); I != E; ++I) {
+    MultiMap.insert(std::make_pair(I->second, I->first));
+  }
+  for (RMapType::const_reverse_iterator I = MultiMap.rbegin(),
+                                        E = MultiMap.rend();
+       I != E; ++I) {
+    char buf[80];
+    snprintf(buf, llvm::array_lengthof(buf), "  %10.6f (%4.1f%%): ", I->first,
+             I->first * 100 / TotalTime);
+    Str << buf << I->second << "\n";
+  }
+}
+
+void TimerStack::dump(Ostream &Str) {
+  update();
+  double TotalTime = LastTimestamp - FirstTimestamp;
+  assert(TotalTime);
+  Str << "Recursive function times:\n";
+  dumpHelper(Str, RecursiveTime, TotalTime);
+  Str << "Non-recursive function times:\n";
+  dumpHelper(Str, LeafTime, TotalTime);
+}
+
 GlobalContext::GlobalContext(llvm::raw_ostream *OsDump,
                              llvm::raw_ostream *OsEmit, VerboseMask Mask,
                              TargetArch Arch, OptLevel Opt,
@@ -122,7 +209,7 @@ GlobalContext::GlobalContext(llvm::raw_ostream *OsDump,
     : StrDump(OsDump), StrEmit(OsEmit), VMask(Mask),
       ConstPool(new ConstantPool()), Arch(Arch), Opt(Opt),
       TestPrefix(TestPrefix), Flags(Flags), HasEmittedFirstMethod(false),
-      RNG("") {}
+      RNG(""), Timers(new TimerStack("main")) {}
 
 // Scan a string for S[0-9A-Z]*_ patterns and replace them with
 // S<num>_ where <num> is the next base-36 value.  If a type name
@@ -384,6 +471,12 @@ ConstantList GlobalContext::getConstantPool(Type Ty) const {
   llvm_unreachable("Unknown type");
 }
 
+void GlobalContext::pushTimer(const IceString &Name) {
+  Timers.get()->push(Name);
+}
+
+void GlobalContext::popTimer(const IceString &Name) { Timers.get()->pop(Name); }
+
 void GlobalContext::dumpStats(const IceString &Name, bool Final) {
   if (Flags.DumpStats) {
     if (Final) {
@@ -395,12 +488,6 @@ void GlobalContext::dumpStats(const IceString &Name, bool Final) {
   }
 }
 
-void Timer::printElapsedUs(GlobalContext *Ctx, const IceString &Tag) const {
-  if (Ctx->isVerbose(IceV_Timing)) {
-    // Prefixing with '#' allows timing strings to be included
-    // without error in textual assembly output.
-    Ctx->getStrDump() << "# " << getElapsedUs() << " usec " << Tag << "\n";
-  }
-}
+void GlobalContext::dumpTimers() { Timers.get()->dump(getStrDump()); }
 
 } // end of namespace Ice