[llvm] [DebugCounter] Add support for non-continous ranges. (PR #89470)

[Nicolai Hähnle via llvm-commits]

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@@ -0,0 +1,151 @@
+//===-- delta-driver.cpp - Tool to drive Automated Delta Debugging --------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// See the llvm-project/llvm/docs/ProgrammersManual.rst to see how to use this
+// tool
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/DebugCounter.h"
+#include "llvm/Support/Program.h"
+
+using namespace llvm;
+
+cl::opt<std::string> ReproductionCmd(cl::Positional, cl::Required);
+
+cl::opt<std::string> StartChunks(cl::Positional, cl::Required);
+
+cl::opt<bool> Pessimist("pessimist", cl::init(false));
+
+SmallVector<Chunk> simplifyChunksList(const SmallVector<Chunk> &Chunks) {
+  SmallVector<Chunk> Res;
+  Res.push_back(Chunks.front());
+  for (unsigned Idx = 1; Idx < Chunks.size(); Idx++) {
+    if (Chunks[Idx].Begin == Res.back().End + 1)
+      Res.back().End = Chunks[Idx].End;
+    else
+      Res.push_back(Chunks[Idx]);
+  }
+  return Res;
+}
+
+bool stillReproducesIssue(const SmallVector<Chunk> &Chunks) {
+  SmallVector<Chunk> SimpleChunks = simplifyChunksList(Chunks);
+
+  std::string ChunkStr;
+  {
+    raw_string_ostream OS(ChunkStr);
+    printChunks(OS, SimpleChunks);
+  }
+
+  errs() << "Checking with: " << ChunkStr << "\n";
+
+  std::vector<StringRef> Argv;
+  Argv.push_back(ReproductionCmd);
+  Argv.push_back(ChunkStr);
+
+  std::string ErrMsg;
+  bool ExecutionFailed;
+  int Result = sys::ExecuteAndWait(Argv[0], Argv, std::nullopt, {}, 0, 0,
+                                   &ErrMsg, &ExecutionFailed);
+  if (ExecutionFailed) {
+    errs() << "failed to execute : " << Argv[0] << " : " << ErrMsg << "\n";
+    exit(1);
+  }
+
+  bool Res = Result != 0;
+  if (Res) {
+    errs() << "SUCCESS : Still Interesting\n";
+  } else {
+    errs() << "FAILURE : Not Interesting\n";
+  }
+  return Res;
+}
+
+static bool increaseGranularity(SmallVector<Chunk> &Chunks) {
+  errs() << "Increasing granularity\n";
+  SmallVector<Chunk> NewChunks;
+  bool SplitOne = false;
+
+  for (auto &C : Chunks) {
+    if (C.Begin == C.End)
+      NewChunks.push_back(C);
+    else {
+      int Half = (C.Begin + C.End) / 2;
+      NewChunks.push_back({C.Begin, Half});
+      NewChunks.push_back({Half + 1, C.End});
+      SplitOne = true;
+    }
+  }
+  if (SplitOne) {
+    Chunks = std::move(NewChunks);
+  }
+  return SplitOne;
+}
+
+int main(int argc, char **argv) {
+  cl::ParseCommandLineOptions(argc, argv);
+
+  SmallVector<Chunk> CurrChunks;
+  if (parseChunks(StartChunks, CurrChunks)) {
+    return 1;
+  }
+
+  auto Program = sys::findProgramByName(ReproductionCmd);
+  if (!Program) {
+    errs() << "failed to find command : " << ReproductionCmd << "\n";
+    return 1;
+  }
+  ReproductionCmd.setValue(Program.get());
+
+  errs() << "Input Checking:\n";
+  if (!stillReproducesIssue(CurrChunks)) {
+    errs() << "starting chunks are not interesting\n";
+    return 1;
+  }
+  if (CurrChunks.size() == 1)
+    increaseGranularity(CurrChunks);
+  if (Pessimist)
+    while (increaseGranularity(CurrChunks)) {
+    }
+  while (1) {
+    SmallDenseSet<unsigned> NotNeedChunks;
+    auto FilteredCopy = [&]() {
+      SmallVector<Chunk> CopiedChunks;
+      for (unsigned SubIdx = 0; SubIdx < CurrChunks.size(); SubIdx++)
+        if (!NotNeedChunks.count(SubIdx))
+          CopiedChunks.push_back(CurrChunks[SubIdx]);
+      return CopiedChunks;
+    };
----------------
nhaehnle wrote:

The logic here is unnecessarily convoluted.

Just reduce (or not) CurrChunks in each iteration through the for loop below, instead of keeping a second NotNeedChunks around for tracking.

https://github.com/llvm/llvm-project/pull/89470