Fix deadlock in Python one-line execution.

Python one-line execution was using ConnectionFileDescriptor to do
a non-blocking read against a pipe.  This won't work on Windows,
as CFD is implemented using select(), and select() only works with
sockets on Windows.

The solution is to use ConnectionGenericFile on Windows, which uses
the native API to do overlapped I/O on the pipe.  This in turn
requires re-implementing Host::Pipe on Windows using native OS
handles instead of the more portable _pipe CRT api.

Reviewed by: Greg Clayton
Differential Revision: http://reviews.llvm.org/D5679

llvm-svn: 219339

1 files changed, 15 insertions, 0 deletions

diff --git a/lldb/source/Interpreter/ScriptInterpreterPython.cpp b/lldb/source/Interpreter/ScriptInterpreterPython.cpp
index 987a168079a..8e03e7b631e 100644
--- a/lldb/source/Interpreter/ScriptInterpreterPython.cpp
+++ b/lldb/source/Interpreter/ScriptInterpreterPython.cpp
@@ -39,6 +39,10 @@
 #include "lldb/Target/Thread.h"
 #include "lldb/Target/ThreadPlan.h"
 
+#if defined(_WIN32)
+#include "lldb/Host/windows/ConnectionGenericFileWindows.h"
+#endif
+
 using namespace lldb;
 using namespace lldb_private;
 
@@ -598,9 +602,20 @@ ScriptInterpreterPython::ExecuteOneLine (const char *command, CommandReturnObjec
                 // Set output to a temporary file so we can forward the results on to the result object
                 
                 Pipe pipe;
+#if defined(_WIN32)
+                // By default Windows does not create a pipe object that can be used for a non-blocking read.
+                // We must explicitly request it.  Furthermore, we can't use an fd for non-blocking read
+                // operations, and must use the native os HANDLE.
+                if (pipe.Open(true, false))
+                {
+                    lldb::file_t read_file = pipe.GetReadNativeHandle();
+                    pipe.ReleaseReadFileDescriptor();
+                    std::unique_ptr<ConnectionGenericFile> conn_ap(new ConnectionGenericFile(read_file, true));
+#else
                 if (pipe.Open())
                 {
                     std::unique_ptr<ConnectionFileDescriptor> conn_ap(new ConnectionFileDescriptor(pipe.ReleaseReadFileDescriptor(), true));
+#endif
                     if (conn_ap->IsConnected())
                     {
                         output_comm.SetConnection(conn_ap.release());