Added Delta IR Reduction Tool

Summary: Tool parses input IR file, and runs the delta debugging algorithm to reduce the functions inside the input file.

Reviewers: alexshap, chandlerc

Subscribers: mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63672

> llvm-svn: 368071

llvm-svn: 368214

1 files changed, 105 insertions, 0 deletions

diff --git a/llvm/tools/llvm-reduce/llvm-reduce.cpp b/llvm/tools/llvm-reduce/llvm-reduce.cpp
new file mode 100644
index 00000000000..6dd733edecb
--- /dev/null
+++ b/llvm/tools/llvm-reduce/llvm-reduce.cpp
@@ -0,0 +1,105 @@
+//===- llvm-reduce.cpp - The LLVM Delta Reduction utility -----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This program tries to reduce an IR test case for a given interesting-ness
+// test. It runs multiple delta debugging passes in order to minimize the input
+// file. It's worth noting that this is a *temporary* tool that will eventually
+// be integrated into the bugpoint tool itself.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DeltaManager.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/IRReader/IRReader.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/raw_ostream.h"
+#include <system_error>
+#include <vector>
+
+using namespace llvm;
+
+static cl::opt<bool> Help("h", cl::desc("Alias for -help"), cl::Hidden);
+static cl::opt<bool> Version("v", cl::desc("Alias for -version"), cl::Hidden);
+
+static cl::opt<std::string> InputFilename(cl::Positional, cl::Required,
+                                          cl::desc("<input llvm ll/bc file>"));
+
+static cl::opt<std::string>
+    TestFilename("test", cl::Required,
+                 cl::desc("Name of the interesting-ness test to be run"));
+
+static cl::list<std::string>
+    TestArguments("test-arg", cl::ZeroOrMore,
+                  cl::desc("Arguments passed onto the interesting-ness test"));
+
+static cl::opt<std::string>
+    OutputFilename("output",
+                   cl::desc("Specify the output file. default: reduced.ll"));
+static cl::alias OutputFileAlias("o", cl::desc("Alias for -output"),
+                                 cl::aliasopt(OutputFilename));
+
+static cl::opt<bool>
+    ReplaceInput("in-place",
+                 cl::desc("WARNING: This option will replace your input file"
+                          "with the reduced version!"));
+
+// Parses IR into a Module and verifies it
+static std::unique_ptr<Module> parseInputFile(StringRef Filename,
+                                              LLVMContext &Ctxt) {
+  SMDiagnostic Err;
+  std::unique_ptr<Module> Result = parseIRFile(Filename, Err, Ctxt);
+  if (!Result) {
+    Err.print("llvm-reduce", errs());
+    return Result;
+  }
+
+  if (verifyModule(*Result, &errs())) {
+    errs() << "Error: " << Filename << " - input module is broken!\n";
+    return std::unique_ptr<Module>();
+  }
+
+  return Result;
+}
+
+int main(int argc, char **argv) {
+  InitLLVM X(argc, argv);
+
+  cl::ParseCommandLineOptions(argc, argv, "LLVM automatic testcase reducer.\n");
+
+  LLVMContext Context;
+  std::unique_ptr<Module> OriginalProgram =
+      parseInputFile(InputFilename, Context);
+
+  // Initialize test environment
+  TestRunner Tester(TestFilename, TestArguments, InputFilename);
+  Tester.setProgram(std::move(OriginalProgram));
+
+  // Try to reduce code
+  runDeltaPasses(Tester);
+  StringRef ReducedFilename = sys::path::filename(Tester.getReducedFilepath());
+
+  if (ReducedFilename == InputFilename) {
+    outs() << "\nCouldnt reduce input :/\n";
+  } else {
+    if (ReplaceInput) // In-place
+      OutputFilename = InputFilename.c_str();
+    else if (OutputFilename.empty())
+      OutputFilename = "reduced.ll";
+    else
+      OutputFilename += ".ll";
+
+    sys::fs::copy_file(Tester.getReducedFilepath(), OutputFilename);
+    outs() << "\nDone reducing! Reduced IR to file: " << OutputFilename << "\n";
+  }
+
+  return 0;
+}