Add pass to print out DebugCounter info

[zhizhouy]

Summary

This patch added a pass to print out {Counter, Skip, StopAfter} info of all passes which have DebugCounter set.

It can be used to monitor how many times does certain transformation happen in a pass, and also help check if -debug-counter option is set correctly.

Please refer to this thread for motivation.

[george.burgess.iv]

Thanks for this!

I don't have a strong feeling for what the right place for this is (e.g. in IR/, ...), and I'm not confident enough with our pass infra and such as a whole to stamp this. I dunno how familiar davide is with these bits; if "not very," we may have to search for someone to poke for a LGTM.

Happily, none of this keeps me from my hobby: nitpicking. :)

include/llvm/IR/DebugCounterPrinter.h

1

Nit: Looks like we're missing a '-' to bring this to 80 characters.

(One of the few benefits of having a skinny monitor: wrapping makes things like this a bit more obvious...)

lib/Support/DebugCounter.cpp

105

nit: Looks like we might be able to shrink this to CounterNames(RegisteredCounters.begin(), RegisteredCounters.end()); and drop the loop below?

It's a bit unfortunate that the std::map isn't directly accessible in RegisteredCounters, since that would give us exactly what we're looking for without this intermediate vector. I'm OK with having the vector, though, since this'll only be run for debugging purposes anyway...

109

nit: please remove the llvm:: (unless it's necessary?)

113

Nit: style guide says to use const auto & unless you need a copy, which I don't think we do.

[zhizhouy]

Thanks for reviewing. Comments fixed.

[zhizhouy]

Just noticed that calling print() function at destructor (like what Statistic class did) when option is set will be more straight forward.

Also the original patch could not work for llc or clang. So I modified this patch, not using an extra pass any more.

[zhizhouy]

Ping for the updated approach...

Thanks for reviewing!

[davide]

lib/Support/DebugCounter.cpp

107

why do you need to sort the counters here?

[zhizhouy]

Thanks for reviewing.

lib/Support/DebugCounter.cpp

107

The reason we sort it here is the order of entries in RegisteredCounters is not stable since it is a map. We want to make sure the each time of the output should be same. So I put it in to a vector with the order of names.

[zhizhouy]

Ping for suggestion, thanks!

[greened]

LGTM, though calling it a "pass" is misleading. It's simply a dump of counter values at the end of execution.

[zhizhouy]

Thanks for reviewing.

though calling it a "pass" is misleading

You're right, the patch was first coming with a pass implementation, but later we find this approach is more direct. Will change the name when submitting it.

[greened]

In D50031#1253407, @zhizhouy wrote:

Thanks for reviewing.

though calling it a "pass" is misleading

You're right, the patch was first coming with a pass implementation, but later we find this approach is more direct. Will change the name when submitting it.

Ok, sounds good. For some reason I'm not able to Accept this so it seems like someone else will need to.

[greened]

Ok, sounds good. For some reason I'm not able to Accept this so it seems like someone else will need to.

Ha! And then somehow I Accepted it. :)

include/llvm/IR/DebugCounterPrinter.h

+//===- DebugCounterPrinter.h - DebugCounterPrinter -------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// The header file for the DebugCounterPrinterPass pass.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_IR_DEBUGCOUNTERPRINTER_H
+#define LLVM_IR_DEBUGCOUNTERPRINTER_H
+
+#include "llvm/IR/Module.h"
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+struct DebugCounterPrinterPass : PassInfoMixin<DebugCounterPrinterPass> {
+  /// \brief Run the pass over the function.
+  ///
+  /// This will print out DebugCounter info on each counter.
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &);
+};
+
+ModulePass *createDebugCounterPrinterPass();
+} // namespace llvm
+
+#endif
 No newline at end of file

include/llvm/InitializePasses.h

 void initializeCrossDSOCFIPass(PassRegistry&);
 void initializeDAEPass(PassRegistry&);
 void initializeDAHPass(PassRegistry&);
 void initializeDCELegacyPassPass(PassRegistry&);
 void initializeDSELegacyPassPass(PassRegistry&);
 void initializeDataFlowSanitizerPass(PassRegistry&);
 void initializeDeadInstEliminationPass(PassRegistry&);
 void initializeDeadMachineInstructionElimPass(PassRegistry&);
+void initializeDebugCounterPrinterLegacyPassPass(PassRegistry&);
 void initializeDelinearizationPass(PassRegistry&);
 void initializeDemandedBitsWrapperPassPass(PassRegistry&);
 void initializeDependenceAnalysisPass(PassRegistry&);
 void initializeDependenceAnalysisWrapperPassPass(PassRegistry&);
 void initializeDetectDeadLanesPass(PassRegistry&);
 void initializeDivergenceAnalysisPass(PassRegistry&);
 void initializeDivRemPairsLegacyPassPass(PassRegistry&);
 void initializeDomOnlyPrinterPass(PassRegistry&);

lib/IR/CMakeLists.txt

 set(LLVM_TARGET_DEFINITIONS AttributesCompatFunc.td)
 tablegen(LLVM AttributesCompatFunc.inc -gen-attrs)
 add_public_tablegen_target(AttributeCompatFuncTableGen)
 
 add_llvm_library(LLVMCore
   AsmWriter.cpp
   Attributes.cpp
   AutoUpgrade.cpp
   BasicBlock.cpp
   Comdat.cpp
   ConstantFold.cpp
   ConstantRange.cpp
   Constants.cpp
   Core.cpp
   DIBuilder.cpp
   DataLayout.cpp
+  DebugCounterPrinter.cpp
   DebugInfo.cpp
   DebugInfoMetadata.cpp
   DebugLoc.cpp
   DiagnosticHandler.cpp
   DiagnosticInfo.cpp
   DiagnosticPrinter.cpp
   Dominators.cpp
   DomTreeUpdater.cpp

lib/IR/Core.cpp

 #include <cstring>
 #include <system_error>
 
 using namespace llvm;
 
 #define DEBUG_TYPE "ir"
 
 void llvm::initializeCore(PassRegistry &Registry) {
+  initializeDebugCounterPrinterLegacyPassPass(Registry);
   initializeDominatorTreeWrapperPassPass(Registry);
   initializePrintModulePassWrapperPass(Registry);
   initializePrintFunctionPassWrapperPass(Registry);
   initializePrintBasicBlockPassPass(Registry);
   initializeSafepointIRVerifierPass(Registry);
   initializeVerifierLegacyPassPass(Registry);
 }
 

lib/IR/DebugCounterPrinter.cpp

+//===- DebugCounterPrinter.cpp - Printer for DebugCounter ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file prints debug counter info as a module pass.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/DebugCounterPrinter.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/DebugCounter.h"
+
+using namespace llvm;
+
+PreservedAnalyses DebugCounterPrinterPass::run(Module &M,
+                                               ModuleAnalysisManager &MAM) {
+  auto DC = &DebugCounter::instance();
+  DC->print(dbgs());
+  return PreservedAnalyses::all();
+}
+
+namespace {
+/// Legacy pass for printing out debug counter info.
+struct DebugCounterPrinterLegacyPass : ModulePass {
+  static char ID;
+  DebugCounterPrinterLegacyPass() : ModulePass(ID) {
+    initializeDebugCounterPrinterLegacyPassPass(
+        *PassRegistry::getPassRegistry());
+  }
+
+  bool runOnModule(Module &M) override {
+    auto DC = &DebugCounter::instance();
+    DC->print(dbgs());
+    return false;
+  }
+};
+} // namespace
+
+char DebugCounterPrinterLegacyPass::ID = 0;
+INITIALIZE_PASS(DebugCounterPrinterLegacyPass, "debug-counter-printer",
+                "Print DebugCounter", false, true)
+
+ModulePass *llvm::createDebugCounterPrinterPass() {
+  return new DebugCounterPrinterLegacyPass();
+}
 No newline at end of file

lib/Passes/PassBuilder.cpp

 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
 #include "llvm/Analysis/ScopedNoAliasAA.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/Analysis/TypeBasedAliasAnalysis.h"
 #include "llvm/CodeGen/PreISelIntrinsicLowering.h"
 #include "llvm/CodeGen/UnreachableBlockElim.h"
+#include "llvm/IR/DebugCounterPrinter.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/PassManager.h"
 #include "llvm/IR/Verifier.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Regex.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Transforms/AggressiveInstCombine/AggressiveInstCombine.h"

lib/Passes/PassRegistry.def

 #define MODULE_PASS(NAME, CREATE_PASS)
 #endif
 MODULE_PASS("always-inline", AlwaysInlinerPass())
 MODULE_PASS("called-value-propagation", CalledValuePropagationPass())
 MODULE_PASS("cg-profile", CGProfilePass())
 MODULE_PASS("constmerge", ConstantMergePass())
 MODULE_PASS("cross-dso-cfi", CrossDSOCFIPass())
 MODULE_PASS("deadargelim", DeadArgumentEliminationPass())
+MODULE_PASS("debug-counter-printer", DebugCounterPrinterPass())
 MODULE_PASS("elim-avail-extern", EliminateAvailableExternallyPass())
 MODULE_PASS("forceattrs", ForceFunctionAttrsPass())
 MODULE_PASS("function-import", FunctionImportPass())
 MODULE_PASS("globaldce", GlobalDCEPass())
 MODULE_PASS("globalopt", GlobalOptPass())
 MODULE_PASS("globalsplit", GlobalSplitPass())
 MODULE_PASS("inferattrs", InferFunctionAttrsPass())
 MODULE_PASS("insert-gcov-profiling", GCOVProfilerPass())

lib/Support/DebugCounter.cpp

 #include "llvm/Support/DebugCounter.h"
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Options.h"
 
 using namespace llvm;
 
 namespace {
if (CounterPair.first.endswith("-skip")) {
     Counters[CounterID].IsSet = true;
   } else {
     errs() << "DebugCounter Error: " << CounterPair.first
            << " does not end with -skip or -count\n";
   }
 }
 
 void DebugCounter::print(raw_ostream &OS) const {
-  OS << "Counters and values:\n";
+  SmallVector<StringRef, 16> CounterNames;
   for (const auto &KV : Counters)
-    OS << left_justify(RegisteredCounters[KV.first], 32) << ": {"
-       << KV.second.Count << "," << KV.second.Skip << ","
-       << KV.second.StopAfter << "}\n";
+    CounterNames.push_back(RegisteredCounters[KV.first]);
+
+  llvm::sort(CounterNames.begin(), CounterNames.end());
+
+  auto &Us = instance();
+  OS << "Counters and values:\n";
+  for (const auto CounterName : CounterNames) {
+    unsigned CounterID = getCounterId(CounterName);
+    OS << left_justify(RegisteredCounters[CounterID], 32) << ": {"
+       << Us.Counters[CounterID].Count << "," << Us.Counters[CounterID].Skip
+       << "," << Us.Counters[CounterID].StopAfter << "}\n";
+  }
 }
 
 LLVM_DUMP_METHOD void DebugCounter::dump() const {
   print(dbgs());
 }

test/Other/debug-counter-printer.ll

+; RUN: opt -S -debug-counter=early-cse-skip=1,early-cse-count=1 -early-cse \
+; RUN:        -debug-counter=newgvn-vn-skip=1,newgvn-vn-count=2 -newgvn \
+; RUN:        -instcombine -debug-counter-printer < %s 2>&1 | FileCheck %s
+;; Test debug counter prints correct info in right order.
+; CHECK-LABEL: Counters and values:
+; CHECK:       early-cse
+; CHECK-SAME:  {4,1,1}
+; CHECK:       instcombine-visit
+; CHECK-SAME:  {12,0,-1}
+; CHECK:       newgvn-vn
+; CHECK-SAME:  {9,1,2}
+define i32 @f1(i32 %a, i32 %b) {
+bb:
+  %add1 = add i32 %a, %b
+  %add2 = add i32 %a, %b
+  %add3 = add i32 %a, %b
+  %add4 = add i32 %a, %b
+  %ret1 = add i32 %add1, %add2
+  %ret2 = add i32 %add3, %add4
+  %ret = add i32 %ret1, %ret2
+  ret i32 %ret
+}
+
+define i32 @f2(i32 %a, i32 %b) {
+bb:
+  %add1 = add i32 %a, %b
+  %add2 = add i32 %a, %b
+  %ret = add i32 %add1, %add2
+  ret i32 %ret
+}
 No newline at end of file