[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, 20 insertions, 0 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
index b1e2075..967dc82 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
@@ -51,6 +51,26 @@ enum class CompressionType {
   LZMA, // Lempel–Ziv–Markov chain algorithm
 };
 
+// Data included in the vFile:fstat packet.
+// https://sourceware.org/gdb/onlinedocs/gdb/struct-stat.html#struct-stat
+struct GDBRemoteFStatData {
+  llvm::support::ubig32_t gdb_st_dev;
+  llvm::support::ubig32_t gdb_st_ino;
+  llvm::support::ubig32_t gdb_st_mode;
+  llvm::support::ubig32_t gdb_st_nlink;
+  llvm::support::ubig32_t gdb_st_uid;
+  llvm::support::ubig32_t gdb_st_gid;
+  llvm::support::ubig32_t gdb_st_rdev;
+  llvm::support::ubig64_t gdb_st_size;
+  llvm::support::ubig64_t gdb_st_blksize;
+  llvm::support::ubig64_t gdb_st_blocks;
+  llvm::support::ubig32_t gdb_st_atime;
+  llvm::support::ubig32_t gdb_st_mtime;
+  llvm::support::ubig32_t gdb_st_ctime;
+};
+static_assert(sizeof(GDBRemoteFStatData) == 64,
+              "size of GDBRemoteFStatData is not 64");
+
 class ProcessGDBRemote;
 
 class GDBRemoteCommunication : public Communication {