Add a another packet to the gdb-remote protocol,

jGetLoadedDynamicLibrariesInfos.  This packet is similar to
qXfer:libraries:read except that lldb supplies the number of solibs
that should be reported about, and the start address for the list
of them.  At the initial process launch we'll read the full list
of solibs linked by the process -- at this point we could be using
qXfer:libraries:read -- but on subsequence solib-loaded notifications,
we'll be fetching a smaller number of solibs, often only one or two.

A typical Mac/iOS GUI app may have a couple hundred different 
solibs loaded  - doing all of the loads via memory reads takes 
a couple of megabytes of traffic between lldb and debugserver.
Having debugserver summarize the load addresses of all the solibs
and sending it in JSON requires a couple of hundred kilobytes
of traffic.  It's a significant performance improvement when 
communicating over a slower channel.

This patch leaves all of the logic for loading the libraries
in DynamicLoaderMacOSXDYLD -- it only call over ot ProcesGDBRemote
to get the JSON result.

If the jGetLoadedDynamicLibrariesInfos packet is not implemented,
the normal technique of using memory read packets to get all of
the details from the target will be used.

<rdar://problem/21007465>

llvm-svn: 241964

1 files changed, 12 insertions, 0 deletions

diff --git a/lldb/tools/debugserver/source/DNB.cpp b/lldb/tools/debugserver/source/DNB.cpp
index 4cde3f87b08..f9cab2ff665 100644
--- a/lldb/tools/debugserver/source/DNB.cpp
+++ b/lldb/tools/debugserver/source/DNB.cpp
@@ -1066,6 +1066,18 @@ DNBGetTSDAddressForThread (nub_process_t pid, nub_thread_t tid, uint64_t plo_pth
     return INVALID_NUB_ADDRESS;
 }
 
+JSONGenerator::ObjectSP 
+DNBGetLoadedDynamicLibrariesInfos (nub_process_t pid, nub_addr_t image_list_address, nub_addr_t image_count)
+{
+    MachProcessSP procSP;
+    if (GetProcessSP (pid, procSP))
+    {
+        return procSP->GetLoadedDynamicLibrariesInfos (pid, image_list_address, image_count);
+    }
+    return JSONGenerator::ObjectSP();
+}
+
+
 
 const char *
 DNBProcessGetExecutablePath (nub_process_t pid)