[lldb/Reproducers] Add test-specific API to set the test CWD

[JDevlieghere]

Summary

The reproducers' working directory is set to the current working directory when
they are initialized. While this is not optimal, as the cwd can change during a
debug session, it has been sufficient so far.

The current approach doesn't work for the API test suite however because dotest
temporarily changes the directory to where the test's Python file lives.

This patch adds an API to tell the reproducers what to set the CWD to. This is
a NO-OP in every mode but capture.

[labath]

It's definitely a hack, but it seems to be fairly well contained.

As an aside, I've always wondered, how much we really need to switch the cwd. Now that we build tests out-of-tree, I would expect most of the file references to be cwd-independent (getBuildArtifact). The only remaining references are probably the ones where we work with source files, which shouldn't be too hard to fix, and also those where we still accidentally create files in the source tree (which this would help eliminate).

[JDevlieghere]

In D79825#2033405, @labath wrote:

It's definitely a hack, but it seems to be fairly well contained.

As an aside, I've always wondered, how much we really need to switch the cwd. Now that we build tests out-of-tree, I would expect most of the file references to be cwd-independent (getBuildArtifact). The only remaining references are probably the ones where we work with source files, which shouldn't be too hard to fix, and also those where we still accidentally create files in the source tree (which this would help eliminate).

Sounds good. About half the API tests are failing without changing the working directory, though I suspect it's mostly the same issue. I've added it to my list of nice-to-haves.

lldb/bindings/interface/SBReproducer.i

 //===-- SWIG Interface for SBReproducer--------------------------*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 namespace lldb {
 class SBReproducer
 {
     public:
         static const char *Capture(const char *path);
         static const char *PassiveReplay(const char *path);
         static bool SetAutoGenerate(bool b);
+        static void SetWorkingDirectory(const char *path);
 };
 }

lldb/include/lldb/API/SBReproducer.h

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);
   static const char *PassiveReplay(const char *path);
   static const char *GetPath();
   static bool SetAutoGenerate(bool b);
   static bool Generate();
+
+  /// The working directory is set to the current working directory when the
+  /// reproducers are initialized. This method allows setting a different
+  /// working directory. This is used by the API test suite  which temporarily
+  /// changes the directory to where the test lives. This is a NO-OP in every
+  /// mode but capture.
+  static void SetWorkingDirectory(const char *path);
 };
 
 } // namespace lldb
 
 #endif

lldb/include/lldb/Utility/Reproducer.h

 class WorkingDirectoryProvider : public Provider<WorkingDirectoryProvider> {
 public:
   WorkingDirectoryProvider(const FileSpec &directory) : Provider(directory) {
     llvm::SmallString<128> cwd;
     if (std::error_code EC = llvm::sys::fs::current_path(cwd))
       return;
     m_cwd = std::string(cwd.str());
   }
+
+  void Update(llvm::StringRef path) { m_cwd = std::string(path); }
+
   struct Info {
     static const char *name;
     static const char *file;
   };
   void Keep() override;
   std::string m_cwd;
   static char ID;
 };

lldb/packages/Python/lldbsuite/test/lldbtest.py

def setUpClass(cls):
         # Change current working directory if ${LLDB_TEST_SRC} is defined.
         # See also dotest.py which sets up ${LLDB_TEST_SRC}.
         if ("LLDB_TEST_SRC" in os.environ):
             full_dir = os.path.join(os.environ["LLDB_TEST_SRC"],
                                     cls.mydir)
             if traceAlways:
                 print("Change dir to:", full_dir, file=sys.stderr)
             os.chdir(full_dir)
+            lldb.SBReproducer.SetWorkingDirectory(full_dir)
 
         # Set platform context.
         cls.platformContext = lldbplatformutil.createPlatformContext()
 
     @classmethod
     def tearDownClass(cls):
         """
         Python unittest framework class teardown fixture.

lldb/source/API/SBReproducer.cpp

 
 const char *SBReproducer::GetPath() {
   static std::string path;
   auto &r = Reproducer::Instance();
   path = r.GetReproducerPath().GetCString();
   return path.c_str();
 }
 
+void SBReproducer::SetWorkingDirectory(const char *path) {
+  if (auto *g = lldb_private::repro::Reproducer::Instance().GetGenerator()) {
+    g->GetOrCreate<WorkingDirectoryProvider>().Update(path);
+  }
+}
+
 char lldb_private::repro::SBProvider::ID = 0;
 const char *SBProvider::Info::name = "sbapi";
 const char *SBProvider::Info::file = "sbapi.bin";