[lldb-dev] gdb-remote lldb prompt race condition
mg11 at csr.com
Wed Aug 20 01:42:47 PDT 2014
I have been seeing another issue with the display of the lldb prompt.
This time it's when I do "target create elf-file", then "gdb-remote
port-number". After the "gdb-remote" command I see the fact that my
process is stopped, e.g.
Process 1 stopped
on the screen. But no (lldb) prompt.
Some investigation revealed that what's *probably* happening is the main
thread after processing the "gdb-remote" returns to it's IOHandler,
which then prints (lldb). However, the inferior's state changes seem to
delivered to stdout via a different thread, basically one which sits in
Debugger::DefaultEventHandler. This subsequent output then, I think,
overwrites the previous (lldb) prompt.
Now in my (and presumably other people's) situation, this issue is
compounded by the speed of the TCP/IP connection to the gdbserver stub,
the "poll the hardware" nature of my stub, and the fact the hardware is
actually simulated - yes over a TCP/IP socket.
FWIW, I resolved this by a horrible (POSIX only) hack, of sleeping for
300ms at the bottom of the CommandInterpreter::HandleCommand function.
@@ -9,6 +9,8 @@
+#include <poll.h> // MG for prompt bugs
@@ -1916,6 +1918,9 @@
log->Printf ("HandleCommand, command %s", (result.Succeeded() ?
"succeeded" : "did not succeed"));
+ // MG wait for remote connects etc. to complete
But this is horrid. Given this, and other prompt issues, I'm wondering
whether whether we need some brave soul, to redesign the current lldb IO
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