[Reproducer] Add version check

[JDevlieghere]

Summary

To ensure a reproducer works correctly, the version of LLDB used for capture and replay must match. Right now the reproducer already contains the LLDB version. However, this is purely informative. LLDB will happily replay a reproducer generated with a different version of LLDB, which can cause subtle differences.

This patch adds a version check which compares the current LLDB version with the one in the reproducer. If the version doesn't match, LLDB will refuse to replay. It also adds an escape hatch to make it possible to still replay the reproducer without having to mess with the recorded version. This might prove useful when you know two versions of LLDB match, even though the version string doesn't. This behavior is triggered by passing a new flag -reproducer-skip-version-check to the lldb driver.

[labath]

Seems legit.

lldb/include/lldb/API/SBReproducer.h

 
 /// The SBReproducer class is special because it bootstraps the capture and
 /// replay of SB API calls. As a result we cannot rely on any other SB objects
 /// in the interface or implementation of this class.
 class LLDB_API SBReproducer {
 public:
   static const char *Capture();
   static const char *Capture(const char *path);
-  static const char *Replay(const char *path);
+  static const char *Replay(const char *path, bool skip_version_check = false);
   static const char *GetPath();
   static bool Generate();
 };
 
 } // namespace lldb
 
 #endif

lldb/source/API/SBReproducer.cpp

 #include "lldb/API/SBCommandInterpreter.h"
 #include "lldb/API/SBData.h"
 #include "lldb/API/SBDebugger.h"
 #include "lldb/API/SBDeclaration.h"
 #include "lldb/API/SBError.h"
 #include "lldb/API/SBFileSpec.h"
 #include "lldb/API/SBHostOS.h"
 #include "lldb/API/SBReproducer.h"
-
 #include "lldb/Host/FileSystem.h"
+#include "lldb/lldb-private.h"
 
 using namespace lldb;
 using namespace lldb_private;
 using namespace lldb_private::repro;
 
 SBRegistry::SBRegistry() {
   Registry &R = *this;
 
const char *SBReproducer::Capture(const char *path) {
   if (auto e =
           Reproducer::Initialize(ReproducerMode::Capture, FileSpec(path))) {
     error = llvm::toString(std::move(e));
     return error.c_str();
   }
   return nullptr;
 }
 
-const char *SBReproducer::Replay(const char *path) {
+const char *SBReproducer::Replay(const char *path, bool skip_version_check) {
   static std::string error;
   if (auto e = Reproducer::Initialize(ReproducerMode::Replay, FileSpec(path))) {
     error = llvm::toString(std::move(e));
     return error.c_str();
   }
 
   repro::Loader *loader = repro::Reproducer::Instance().GetLoader();
   if (!loader) {
     error = "unable to get replay loader.";
     return error.c_str();
   }
 
+  if (!skip_version_check) {
+    llvm::Expected<std::string> version = loader->LoadBuffer<VersionProvider>();
+    if (!version) {
+      error = llvm::toString(version.takeError());
+      return error.c_str();
+    }
+    if (lldb_private::GetVersion() != llvm::StringRef(*version).rtrim()) {
+      error = "reproducer capture and replay version don't match:\n";
+      error.append("reproducer captured with:\n");
+      error.append(*version);
+      error.append("reproducer replayed with:\n");
+      error.append(lldb_private::GetVersion());
+      return error.c_str();
+    }
+  }
+
   FileSpec file = loader->GetFile<SBProvider::Info>();
   if (!file) {
     error = "unable to get replay data from reproducer.";
     return error.c_str();
   }
 
   SBRegistry registry;
   registry.Replay(file);

lldb/test/Shell/Reproducer/TestVersionCheck.test

+# REQUIRES: system-darwin
+
+# This tests the reproducer version check.
+
+# RUN: rm -rf %t.repro
+# RUN: %clang_host %S/Inputs/simple.c -g -o %t.out
+# RUN: %lldb -x -b -s %S/Inputs/FileCapture.in --capture --capture-path %t.repro %t.out | FileCheck %s --check-prefix CHECK --check-prefix CAPTURE
+
+# Make sure that replay works.
+# RUN: %lldb --replay %t.repro | FileCheck %s --check-prefix CHECK --check-prefix REPLAY
+
+# Change the reproducer version.
+# RUN: echo "bogus" >> %t.repro/version.txt
+
+# Make sure that replay works.
+# RUN: not %lldb --replay %t.repro 2>&1 | FileCheck %s --check-prefix ERROR
+
+# Make sure that we can circumvent the version check with -reproducer-skip-version-check.
+# RUN: %lldb --replay %t.repro -reproducer-skip-version-check | FileCheck %s --check-prefix CHECK --check-prefix REPLAY
+
+# CAPTURE: testing
+# REPLAY-NOT: testing
+
+# CHECK: Process {{.*}} exited
+
+# CAPTURE: Reproducer is in capture mode.
+# CAPTURE: Reproducer written
+
+# ERROR: error: reproducer replay failed: reproducer capture and replay version don't match

lldb/tools/driver/Driver.cpp

EXAMPLES:
 
   Note: In REPL mode no file is loaded, so commands specified to run after
   loading the file (via -o or -s) will be ignored.)___";
   llvm::outs() << examples << '\n';
 }
 
 llvm::Optional<int> InitializeReproducer(opt::InputArgList &input_args) {
   if (auto *replay_path = input_args.getLastArg(OPT_replay)) {
-    if (const char *error = SBReproducer::Replay(replay_path->getValue())) {
+    const bool skip_version_check = input_args.hasArg(OPT_skip_version_check);
+    if (const char *error =
+            SBReproducer::Replay(replay_path->getValue(), skip_version_check)) {
       WithColor::error() << "reproducer replay failed: " << error << '\n';
       return 1;
     }
     return 0;
   }
 
   bool capture = input_args.hasArg(OPT_capture);
   auto *capture_path = input_args.getLastArg(OPT_capture_path);

lldb/tools/driver/Options.td

 def capture: F<"capture">,
   HelpText<"Tells the debugger to capture a reproducer.">;
 def capture_path: Separate<["--", "-"], "capture-path">,
   MetaVarName<"<filename>">,
   HelpText<"Tells the debugger to use the given filename for the reproducer.">;
 def replay: Separate<["--", "-"], "replay">,
   MetaVarName<"<filename>">,
   HelpText<"Tells the debugger to replay a reproducer from <filename>.">;
+def skip_version_check: F<"reproducer-skip-version-check">,
+  HelpText<"Skip the reproducer version check.">;
 
 def REM : R<["--"], "">;