[Lldb-commits] [lldb] Use the root directory as the SDK root on POSIX platforms (PR #146963)

[Adrian Prantl via lldb-commits]

https://github.com/adrian-prantl updated https://github.com/llvm/llvm-project/pull/146963

>From 16b7748cf38aaade5185a1073d2755abb2c40d12 Mon Sep 17 00:00:00 2001
From: CodingCarpincho <CodingCapybara at apple.com>
Date: Thu, 3 Jul 2025 13:54:46 -0700
Subject: [PATCH] Use the root directory as the SDK root on POSIX platforms

LLDB has the concept of an "SDK root", which expresses where the
system libraries and so which are necessary for debugging can be
found. On POSIX platforms, the SDK root is just the root of the
file system, or /.

We need to implement the appropriate method on HostInfoPosix to
prevent the use of the default implementation for which just returns
an error.

This change is needed to support the Swift REPL but may be useful
for other use cases as well.
---
 lldb/include/lldb/Host/posix/HostInfoPosix.h | 2 ++
 lldb/source/Host/posix/HostInfoPosix.cpp     | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/lldb/include/lldb/Host/posix/HostInfoPosix.h b/lldb/include/lldb/Host/posix/HostInfoPosix.h
index 779b67bd66eda..c4a7f13674f40 100644
--- a/lldb/include/lldb/Host/posix/HostInfoPosix.h
+++ b/lldb/include/lldb/Host/posix/HostInfoPosix.h
@@ -39,6 +39,8 @@ class HostInfoPosix : public HostInfoBase {
   static llvm::VersionTuple GetOSVersion();
   static std::optional<std::string> GetOSBuildString();
 
+  static llvm::Expected<llvm::StringRef> GetSDKRoot(SDKOptions options);
+
 protected:
   static bool ComputeSupportExeDirectory(FileSpec &file_spec);
   static bool ComputeHeaderDirectory(FileSpec &file_spec);
diff --git a/lldb/source/Host/posix/HostInfoPosix.cpp b/lldb/source/Host/posix/HostInfoPosix.cpp
index 879dccfd353be..704f77891c829 100644
--- a/lldb/source/Host/posix/HostInfoPosix.cpp
+++ b/lldb/source/Host/posix/HostInfoPosix.cpp
@@ -140,6 +140,12 @@ std::optional<std::string> PosixUserIDResolver::DoGetGroupName(id_t gid) {
   return std::nullopt;
 }
 
+/// The SDK is the directory where the system C headers, libraries, can be
+/// found. On POSIX platforms this is simply the root directory.
+llvm::Expected<llvm::StringRef> HostInfoPosix::GetSDKRoot(SDKOptions options) {
+  return "/";
+}
+
 static llvm::ManagedStatic<PosixUserIDResolver> g_user_id_resolver;
 
 UserIDResolver &HostInfoPosix::GetUserIDResolver() {