Host: generalise `GetXcodeSDKPath`

[compnerd]

Summary

This generalises the GetXcodeSDKPath hook to a GetSDKRoot path which
will be re-used for the Windows support to compute a language specific
SDK path on the platform. Because there may be other options that we
wish to use to compute the SDK path, sink the XcodeSDK parameter into
a structure which can pass a disaggregated set of options. Furthermore,
optionalise the parameter as Xcode is not available for all platforms.

[JDevlieghere]

LGTM. Thanks Saleem!

[mgorny]

This change broke building with GCC:

samu: job failed: /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DHAVE_ROUND -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_LIBCPP_ENABLE_ASSERTIONS -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb_build/source/Host -I/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/source/Host -I/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/include -I/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb_build/include -I/usr/lib/llvm/17/include -I/usr/include/python3.11 -I/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/tools/clang/include -I/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb_build/../clang/include -I/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/source -I/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb_build/source -isystem /usr/include/libxml2  -march=znver2 --param=l1-cache-size=32 --param=l1-cache-line-size=64 -O2 -pipe -frecord-gcc-switches -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -Wimplicit-fallthrough -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -Wno-deprecated-declarations -Wno-unknown-pragmas -Wno-strict-aliasing -Wno-stringop-truncation -std=c++17 -UNDEBUG -MD -MT source/Host/CMakeFiles/lldbHost.dir/posix/PipePosix.cpp.o -MF source/Host/CMakeFiles/lldbHost.dir/posix/PipePosix.cpp.o.d -o source/Host/CMakeFiles/lldbHost.dir/posix/PipePosix.cpp.o -c /var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/source/Host/posix/PipePosix.cpp
In file included from /var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/include/lldb/Host/posix/HostInfoPosix.h:12,
                 from /var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/include/lldb/Host/linux/HostInfoLinux.h:12,
                 from /var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/include/lldb/Host/HostInfo.h:43,
                 from /var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/source/Host/posix/PipePosix.cpp:10:
/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/include/lldb/Host/HostInfoBase.h:130:29: error: declaration of ‘std::optional<lldb_private::XcodeSDK> lldb_private::HostInfoBase::SDKOptions::XcodeSDK’ changes meaning of ‘XcodeSDK’ [-Wchanges-meaning]
  130 |     std::optional<XcodeSDK> XcodeSDK;
      |                             ^~~~~~~~
/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/include/lldb/Host/HostInfoBase.h:130:19: note: used here to mean ‘class lldb_private::XcodeSDK’
  130 |     std::optional<XcodeSDK> XcodeSDK;
      |                   ^~~~~~~~
In file included from /var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/include/lldb/Host/HostInfoBase.h:16:
/var/tmp/portage/dev-util/lldb-17.0.0_pre20230429/work/lldb/include/lldb/Utility/XcodeSDK.h:24:7: note: declared here
   24 | class XcodeSDK {
      |       ^~~~~~~~
samu: subcommands failed

[cmtice]

I'm seeing the same build failures reported by mgorny. Would you consider reverting this patch until you can fix it?

[dyung]

I’m also seeing this fail on 2 buildbots:

https://lab.llvm.org/buildbot/#/builders/217/builds/20568
https://lab.llvm.org/buildbot/#/builders/243/builds/5576

lldb/include/lldb/Host/HostInfoBase.h

 
 class FileSpec;
 
 struct SharedCacheImageInfo {
   UUID uuid;
   lldb::DataBufferSP data_sp;
 };
 
+namespace {
+struct HostInfoError : public llvm::ErrorInfo<HostInfoError> {
+  static char ID;
+  const std::string message_;
+
+  HostInfoError(const std::string message) : message_(std::move(message)) {}
+
+  void log(llvm::raw_ostream &OS) const override { OS << "HostInfoError"; }
+
+  std::error_code convertToErrorCode() const override {
+    return llvm::inconvertibleErrorCode();
+  }
+};
+
+char HostInfoError::ID = 0;
+}
+
 class HostInfoBase {
 private:
   // Static class, unconstructable.
   HostInfoBase() = default;
   ~HostInfoBase() = default;
 
 public:
   /// A helper function for determining the liblldb location. It receives a
public:
   /// ArchSpec object.
   static ArchSpec GetAugmentedArchSpec(llvm::StringRef triple);
 
   static bool ComputePathRelativeToLibrary(FileSpec &file_spec,
                                            llvm::StringRef dir);
 
   static FileSpec GetXcodeContentsDirectory() { return {}; }
   static FileSpec GetXcodeDeveloperDirectory() { return {}; }
-  
-  /// Return the directory containing a specific Xcode SDK.
-  static llvm::Expected<llvm::StringRef> GetXcodeSDKPath(XcodeSDK sdk) {
-    return "";
+  struct SDKOptions {
+    std::optional<XcodeSDK> XcodeSDK;
+  };
+
+  /// Return the directory containing something like a SDK (reused for Swift).
+  static llvm::Expected<llvm::StringRef> GetSDKRoot(SDKOptions options) {
+    return llvm::make_error<HostInfoError>("cannot determine SDK root");
   }
 
   /// Return information about module \p image_name if it is loaded in
   /// the current process's address space.
   static SharedCacheImageInfo
   GetSharedCacheImageInfo(llvm::StringRef image_name) {
     return {};
   }

lldb/include/lldb/Host/macosx/HostInfoMacOSX.h

public:
   static llvm::VersionTuple GetOSVersion();
   static llvm::VersionTuple GetMacCatalystVersion();
   static std::optional<std::string> GetOSBuildString();
   static FileSpec GetProgramFileSpec();
   static FileSpec GetXcodeContentsDirectory();
   static FileSpec GetXcodeDeveloperDirectory();
 
   /// Query xcrun to find an Xcode SDK directory.
-  static llvm::Expected<llvm::StringRef> GetXcodeSDKPath(XcodeSDK sdk);
+  static llvm::Expected<llvm::StringRef> GetSDKRoot(SDKOptions options);
 
   /// Shared cache utilities
   static SharedCacheImageInfo
   GetSharedCacheImageInfo(llvm::StringRef image_name);
 
 protected:
   static bool ComputeSupportExeDirectory(FileSpec &file_spec);
   static void ComputeHostArchitectureSupport(ArchSpec &arch_32,
                                              ArchSpec &arch_64);
   static bool ComputeHeaderDirectory(FileSpec &file_spec);
   static bool ComputeSystemPluginsDirectory(FileSpec &file_spec);
   static bool ComputeUserPluginsDirectory(FileSpec &file_spec);
 };
 }
 
 #endif

lldb/source/Core/Module.cpp

   std::lock_guard<std::recursive_mutex> guard(m_mutex);
   if (auto remapped = m_source_mappings.RemapPath(path))
     return remapped->GetPath();
   return {};
 }
 
 void Module::RegisterXcodeSDK(llvm::StringRef sdk_name,
                               llvm::StringRef sysroot) {
-  XcodeSDK sdk(sdk_name.str());
-  auto sdk_path_or_err = HostInfo::GetXcodeSDKPath(sdk);
+  auto sdk_path_or_err = HostInfo::GetSDKRoot(HostInfo::SDKOptions{sdk_name.str()});
 
   if (!sdk_path_or_err) {
     Debugger::ReportError("Error while searching for Xcode SDK: " +
                           toString(sdk_path_or_err.takeError()));
     return;
   }
 
   auto sdk_path = *sdk_path_or_err;

lldb/source/Host/macosx/objcxx/HostInfoMacOSX.mm

if (!env_developer_dir.empty()) {
       std::string xcode_contents_dir =
           XcodeSDK::FindXcodeContentsDirectoryInPath(env_developer_dir);
       if (!xcode_contents_dir.empty()) {
         g_xcode_contents_path = FileSpec(xcode_contents_dir);
         return;
       }
     }
 
-    auto sdk_path_or_err = HostInfo::GetXcodeSDKPath(XcodeSDK::GetAnyMacOS());
+    auto sdk_path_or_err = HostInfo::GetSDKRoot(SDKOptions{XcodeSDK::GetAnyMacOS()});
     if (!sdk_path_or_err) {
       Log *log = GetLog(LLDBLog::Host);
       LLDB_LOGF(log, "Error while searching for Xcode SDK: %s",
                 toString(sdk_path_or_err.takeError()).c_str());
       return;
     }
     FileSpec fspec(*sdk_path_or_err);
     if (fspec) {
llvm::Expected<std::string> GetXcodeSDK(XcodeSDK sdk) {
   if (!FileSystem::Instance().Exists(path)) {
     LLDB_LOGF(log, "SDK returned by xcrun doesn't exist");
     return llvm::createStringError(llvm::inconvertibleErrorCode(),
                                    "SDK returned by xcrun doesn't exist");
   }
   return path;
 }
 
-llvm::Expected<llvm::StringRef> HostInfoMacOSX::GetXcodeSDKPath(XcodeSDK sdk) {
+llvm::Expected<llvm::StringRef> HostInfoMacOSX::GetSDKRoot(SDKOptions options) {
   struct ErrorOrPath {
     std::string str;
     bool is_error;
   };
   static llvm::StringMap<ErrorOrPath> g_sdk_path;
   static std::mutex g_sdk_path_mutex;
 
   std::lock_guard<std::mutex> guard(g_sdk_path_mutex);
   LLDB_SCOPED_TIMER();
 
   auto key = sdk.GetString();
   auto it = g_sdk_path.find(key);
   if (it != g_sdk_path.end()) {
     if (it->second.is_error)
       return llvm::createStringError(llvm::inconvertibleErrorCode(),
                                      it->second.str);
     else
       return it->second.str;
   }
-  auto path_or_err = GetXcodeSDK(sdk);
+  auto path_or_err = GetXcodeSDK(options.XcodeSDK);
   if (!path_or_err) {
     std::string error = toString(path_or_err.takeError());
     g_sdk_path.insert({key, {error, true}});
     return llvm::createStringError(llvm::inconvertibleErrorCode(), error);
   }
   auto it_new = g_sdk_path.insert({key, {*path_or_err, false}});
   return it_new.first->second.str;
 }

lldb/source/Plugins/Platform/MacOSX/PlatformAppleSimulator.cpp

llvm::transform(m_supported_triples, result.begin(),
                   [](llvm::StringRef triple) { return ArchSpec(triple); });
   return result;
 }
 
 static llvm::StringRef GetXcodeSDKDir(std::string preferred,
                                       std::string secondary) {
   llvm::StringRef sdk;
   auto get_sdk = [&](std::string sdk) -> llvm::StringRef {
-    auto sdk_path_or_err = HostInfo::GetXcodeSDKPath(XcodeSDK(std::move(sdk)));
+    auto sdk_path_or_err = HostInfo::GetSDKRoot(SDKOptions{XcodeSDK(std::move(sdk))});
     if (!sdk_path_or_err) {
       Debugger::ReportError("Error while searching for Xcode SDK: " +
                             toString(sdk_path_or_err.takeError()));
       return {};
     }
     return *sdk_path_or_err;
   };
 

lldb/source/Plugins/Platform/MacOSX/PlatformMacOSX.cpp

sdk_path.Printf("%s/Developer/Platforms/MacOSX.platform/Developer/"
                     "SDKs/MacOSX%u.%u.sdk",
                     fspec.GetPath().c_str(), version.getMajor(),
                     *version.getMinor());
     if (FileSystem::Instance().Exists(fspec))
       return ConstString(sdk_path.GetString());
   }
 
   // Use the default SDK as a fallback.
-  auto sdk_path_or_err = HostInfo::GetXcodeSDKPath(XcodeSDK::GetAnyMacOS());
+  auto sdk_path_or_err = HostInfo::GetSDKRoot(HostInfo::SDKOptions{XcodeSDK::GetAnyMacOS()});
   if (!sdk_path_or_err) {
     Debugger::ReportError("Error while searching for Xcode SDK: " +
                           toString(sdk_path_or_err.takeError()));
     return {};
   }
 
   FileSpec fspec(*sdk_path_or_err);
   if (fspec) {

lldb/unittests/Host/HostInfoTest.cpp

TEST_F(HostInfoTest, GetHostname) {
   // Check non-empty string input works correctly.
   std::string s("abc");
   EXPECT_TRUE(HostInfo::GetHostname(s));
 }
 
 #if defined(__APPLE__)
 TEST_F(HostInfoTest, GetXcodeSDK) {
   auto get_sdk = [](std::string sdk, bool error = false) -> llvm::StringRef {
-    auto sdk_path_or_err = HostInfo::GetXcodeSDKPath(XcodeSDK(std::move(sdk)));
+    auto sdk_path_or_err = HostInfo::GetSDKRoot(SDKOptions{XcodeSDK(std::move(sdk))});
     if (!error) {
       EXPECT_TRUE((bool)sdk_path_or_err);
       return *sdk_path_or_err;
     }
     EXPECT_FALSE((bool)sdk_path_or_err);
     llvm::consumeError(sdk_path_or_err.takeError());
     return {};
   };