[llvm] f041204 - llvm-reduce: Stop checking workitem is interesting before each pass

[Matt Arsenault via llvm-commits]

Author: Matt Arsenault
Date: 2022-10-28T16:39:09-07:00
New Revision: f041204ec896a24d19f44b9095660ab8559ebbc7

URL: https://github.com/llvm/llvm-project/commit/f041204ec896a24d19f44b9095660ab8559ebbc7
DIFF: https://github.com/llvm/llvm-project/commit/f041204ec896a24d19f44b9095660ab8559ebbc7.diff

LOG: llvm-reduce: Stop checking workitem is interesting before each pass

Each delta pass run should have guaranteed the output is still
interesting, so it should be pointless to recheck this each
iteration. I have many issues that take multiple minutes
to reproduce, so this ends up being a huge waste of time.

Also, remove broken line counting. This never worked, since
getLines was failing to open the temporary file which was just
deleted.

Added: 
    

Modified: 
    llvm/tools/llvm-reduce/deltas/Delta.cpp
    llvm/tools/llvm-reduce/llvm-reduce.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/tools/llvm-reduce/deltas/Delta.cpp b/llvm/tools/llvm-reduce/deltas/Delta.cpp
index 736e62361c546..c29c8af3e25d8 100644
--- a/llvm/tools/llvm-reduce/deltas/Delta.cpp
+++ b/llvm/tools/llvm-reduce/deltas/Delta.cpp
@@ -67,8 +67,8 @@ void writeBitcode(ReducerWorkItem &M, raw_ostream &OutStream);
 void readBitcode(ReducerWorkItem &M, MemoryBufferRef Data, LLVMContext &Ctx,
                  const char *ToolName);
 
-bool isReduced(ReducerWorkItem &M, TestRunner &Test,
-               SmallString<128> &CurrentFilepath) {
+bool isReduced(ReducerWorkItem &M, TestRunner &Test) {
+  SmallString<128> CurrentFilepath;
   // Write ReducerWorkItem to tmp file
   int FD;
   std::error_code EC = sys::fs::createTemporaryFile(
@@ -104,18 +104,6 @@ bool isReduced(ReducerWorkItem &M, TestRunner &Test,
   return Test.run(CurrentFilepath);
 }
 
-/// Counts the amount of lines for a given file
-static int getLines(StringRef Filepath) {
-  int Lines = 0;
-  std::string CurrLine;
-  std::ifstream FileStream{std::string(Filepath)};
-
-  while (std::getline(FileStream, CurrLine))
-    ++Lines;
-
-  return Lines;
-}
-
 /// Splits Chunks in half and prints them.
 /// If unable to split (when chunk size is 1) returns false.
 static bool increaseGranularity(std::vector<Chunk> &Chunks) {
@@ -195,8 +183,7 @@ CheckChunk(Chunk &ChunkToCheckForUninterestingness,
     errs() << "\n";
   }
 
-  SmallString<128> CurrentFilepath;
-  if (!isReduced(*Clone, Test, CurrentFilepath)) {
+  if (!isReduced(*Clone, Test)) {
     // Program became non-reduced, so this chunk appears to be interesting.
     if (Verbose)
       errs() << "\n";
@@ -239,12 +226,6 @@ void llvm::runDeltaPass(TestRunner &Test, ReductionFunc ExtractChunksFromModule,
          "input module is broken before making changes");
   errs() << "*** " << Message << "...\n";
 
-  SmallString<128> CurrentFilepath;
-  if (!isReduced(Test.getProgram(), Test, CurrentFilepath)) {
-    errs() << "\nInput isn't interesting! Verify interesting-ness test\n";
-    exit(1);
-  }
-
   int Targets;
   {
     // Count the number of chunks by counting the number of calls to
@@ -257,7 +238,7 @@ void llvm::runDeltaPass(TestRunner &Test, ReductionFunc ExtractChunksFromModule,
 
     assert(!verifyReducerWorkItem(Test.getProgram(), &errs()) &&
            "input module is broken after counting chunks");
-    assert(isReduced(Test.getProgram(), Test, CurrentFilepath) &&
+    assert(isReduced(Test.getProgram(), Test) &&
            "input module no longer interesting after counting chunks");
 
 #ifndef NDEBUG
@@ -393,10 +374,9 @@ void llvm::runDeltaPass(TestRunner &Test, ReductionFunc ExtractChunksFromModule,
       FoundAtLeastOneNewUninterestingChunkWithCurrentGranularity = true;
       UninterestingChunks.insert(ChunkToCheckForUninterestingness);
       ReducedProgram = std::move(Result);
-      if (Verbose)
-        errs() << " **** SUCCESS | lines: " << getLines(CurrentFilepath)
-               << "\n";
-      writeOutput(*ReducedProgram, "Saved new best reduction to ");
+
+      // FIXME: Report meaningful progress info
+      writeOutput(*ReducedProgram, " **** SUCCESS | Saved new best reduction to ");
     }
     // Delete uninteresting chunks
     erase_if(ChunksStillConsideredInteresting,

diff  --git a/llvm/tools/llvm-reduce/llvm-reduce.cpp b/llvm/tools/llvm-reduce/llvm-reduce.cpp
index 13c6edc64e238..5cadaa73a682d 100644
--- a/llvm/tools/llvm-reduce/llvm-reduce.cpp
+++ b/llvm/tools/llvm-reduce/llvm-reduce.cpp
@@ -92,6 +92,8 @@ static cl::opt<int>
 
 static codegen::RegisterCodeGenFlags CGF;
 
+bool isReduced(ReducerWorkItem &M, TestRunner &Test);
+
 void writeOutput(ReducerWorkItem &M, StringRef Message) {
   if (ReplaceInput) // In-place
     OutputFilename = InputFilename.c_str();
@@ -182,6 +184,15 @@ int main(int Argc, char **Argv) {
   TestRunner Tester(TestFilename, TestArguments, std::move(OriginalProgram),
                     std::move(TM), Argv[0]);
 
+  // This parses and writes out the testcase into a temporary file copy for the
+  // test, rather than evaluating the source IR directly. This is for the
+  // convenience of lit tests; the stripped out comments may have broken the
+  // interestingness checks.
+  if (!isReduced(Tester.getProgram(), Tester)) {
+    errs() << "\nInput isn't interesting! Verify interesting-ness test\n";
+    return 1;
+  }
+
   // Try to reduce code
   runDeltaPasses(Tester, MaxPassIterations);