[lldb] [gdb-remote] Implement fallback to vFile:stat for GetFileSize()

Implement a fallback to getting the file size via vFile:stat packet
when the remote server does not implement vFile:size.  This makes it
possible to query file sizes from remote gdbserver.

Note that unlike vFile:size, the fallback will not work if the server is
unable to open the file.

While at it, add a few tests for the 'platform get-size' command.

Differential Revision: https://reviews.llvm.org/D107780

1 files changed, 7 insertions, 1 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
index 0062508..f1a78ce 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
@@ -376,6 +376,12 @@ public:
 
   bool CloseFile(lldb::user_id_t fd, Status &error);
 
+  llvm::Optional<GDBRemoteFStatData> FStat(lldb::user_id_t fd);
+
+  // NB: this is just a convenience wrapper over open() + fstat().  It does not
+  // work if the file cannot be opened.
+  llvm::Optional<GDBRemoteFStatData> Stat(const FileSpec &file_spec);
+
   lldb::user_id_t GetFileSize(const FileSpec &file_spec);
 
   void AutoCompleteDiskFileOrDirectory(CompletionRequest &request,
@@ -581,7 +587,7 @@ protected:
       m_supports_QEnvironment : 1, m_supports_QEnvironmentHexEncoded : 1,
       m_supports_qSymbol : 1, m_qSymbol_requests_done : 1,
       m_supports_qModuleInfo : 1, m_supports_jThreadsInfo : 1,
-      m_supports_jModulesInfo : 1;
+      m_supports_jModulesInfo : 1, m_supports_vFileSize : 1;
 
   /// Current gdb remote protocol process identifier for all other operations
   lldb::pid_t m_curr_pid = LLDB_INVALID_PROCESS_ID;