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llvm-project/lldb/source/Core/Communication.cpp
Greg Clayton 8b2fe6dcbd Modified LLDB expressions to not have to JIT and run code just to see variable 
values or persistent expression variables. Now if an expression consists of
a value that is a child of a variable, or of a persistent variable only, we
will create a value object for it and make a ValueObjectConstResult from it to
freeze the value (for program variables only, not persistent variables) and
avoid running JITed code. For everything else we still parse up and JIT code
and run it in the inferior. 

There was also a lot of clean up in the expression code. I made the 
ClangExpressionVariables be stored in collections of shared pointers instead
of in collections of objects. This will help stop a lot of copy constructors on
these large objects and also cleans up the code considerably. The persistent
clang expression variables were moved over to the Target to ensure they persist
across process executions.

Added the ability for lldb_private::Target objects to evaluate expressions.
We want to evaluate expressions at the target level in case we aren't running
yet, or we have just completed running. We still want to be able to access the
persistent expression variables between runs, and also evaluate constant 
expressions. 

Added extra logging to the dynamic loader plug-in for MacOSX. ModuleList objects
can now dump their contents with the UUID, arch and full paths being logged with
appropriate prefix values.

Thread hardened the Communication class a bit by making the connection auto_ptr
member into a shared pointer member and then making a local copy of the shared
pointer in each method that uses it to make sure another thread can't nuke the
connection object while it is being used by another thread.

Added a new file to the lldb/test/load_unload test that causes the test a.out file
to link to the libd.dylib file all the time. This will allow us to test using
the DYLD_LIBRARY_PATH environment variable after moving libd.dylib somewhere else.

llvm-svn: 121745
2010-12-14 02:59:59 +00:00

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//===-- Communication.cpp ---------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes
#include "lldb/lldb-private-log.h"
#include "lldb/Core/Communication.h"
#include "lldb/Core/Connection.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Timer.h"
#include "lldb/Core/Event.h"
#include <string.h>
using namespace lldb;
using namespace lldb_private;
//----------------------------------------------------------------------
// Constructor
//----------------------------------------------------------------------
Communication::Communication(const char *name) :
Broadcaster (name),
m_connection_sp (),
m_read_thread (LLDB_INVALID_HOST_THREAD),
m_read_thread_enabled (false),
m_bytes(),
m_bytes_mutex (Mutex::eMutexTypeRecursive),
m_callback (NULL),
m_callback_baton (NULL),
m_close_on_eof (true)
{
lldb_private::LogIfAnyCategoriesSet (LIBLLDB_LOG_OBJECT | LIBLLDB_LOG_COMMUNICATION,
"%p Communication::Communication (name = %s)",
this, name);
}
//----------------------------------------------------------------------
// Destructor
//----------------------------------------------------------------------
Communication::~Communication()
{
lldb_private::LogIfAnyCategoriesSet (LIBLLDB_LOG_OBJECT | LIBLLDB_LOG_COMMUNICATION,
"%p Communication::~Communication (name = %s)",
this, m_broadcaster_name.AsCString(""));
Clear();
}
void
Communication::Clear()
{
StopReadThread (NULL);
Disconnect (NULL);
}
ConnectionStatus
Communication::BytesAvailable (uint32_t timeout_usec, Error *error_ptr)
{
lldb_private::LogIfAnyCategoriesSet (LIBLLDB_LOG_COMMUNICATION, "%p Communication::BytesAvailable (timeout_usec = %u)", this, timeout_usec);
lldb::ConnectionSP connection_sp (m_connection_sp);
if (connection_sp.get())
return connection_sp->BytesAvailable (timeout_usec, error_ptr);
if (error_ptr)
error_ptr->SetErrorString("Invalid connection.");
return eConnectionStatusNoConnection;
}
ConnectionStatus
Communication::Connect (const char *url, Error *error_ptr)
{
Clear();
lldb_private::LogIfAnyCategoriesSet (LIBLLDB_LOG_COMMUNICATION, "%p Communication::Connect (url = %s)", this, url);
lldb::ConnectionSP connection_sp (m_connection_sp);
if (connection_sp.get())
return connection_sp->Connect (url, error_ptr);
if (error_ptr)
error_ptr->SetErrorString("Invalid connection.");
return eConnectionStatusNoConnection;
}
ConnectionStatus
Communication::Disconnect (Error *error_ptr)
{
lldb_private::LogIfAnyCategoriesSet (LIBLLDB_LOG_COMMUNICATION, "%p Communication::Disconnect ()", this);
lldb::ConnectionSP connection_sp (m_connection_sp);
if (connection_sp.get())
{
ConnectionStatus status = connection_sp->Disconnect (error_ptr);
// We currently don't protect connection_sp with any mutex for
// multi-threaded environments. So lets not nuke our connection class
// without putting some multi-threaded protections in. We also probably
// don't want to pay for the overhead it might cause if every time we
// access the connection we have to take a lock.
//
// This auto_ptr will cleanup after itself when this object goes away,
// so there is no need to currently have it destroy itself immediately
// upon disconnnect.
//connection_sp.reset();
return status;
}
return eConnectionStatusNoConnection;
}
bool
Communication::IsConnected () const
{
lldb::ConnectionSP connection_sp (m_connection_sp);
if (connection_sp.get())
return connection_sp->IsConnected ();
return false;
}
bool
Communication::HasConnection () const
{
return m_connection_sp.get() != NULL;
}
size_t
Communication::Read (void *dst, size_t dst_len, uint32_t timeout_usec, ConnectionStatus &status, Error *error_ptr)
{
lldb_private::LogIfAnyCategoriesSet (LIBLLDB_LOG_COMMUNICATION,
"%p Communication::Read (dst = %p, dst_len = %zu, timeout_usec = %u) connection = %p",
this,
dst,
dst_len,
timeout_usec,
m_connection_sp.get());
if (m_read_thread != LLDB_INVALID_HOST_THREAD)
{
// We have a dedicated read thread that is getting data for us
size_t cached_bytes = GetCachedBytes (dst, dst_len);
if (cached_bytes > 0 || timeout_usec == 0)
{
status = eConnectionStatusSuccess;
return cached_bytes;
}
if (m_connection_sp.get() == NULL)
{
if (error_ptr)
error_ptr->SetErrorString("Invalid connection.");
status = eConnectionStatusNoConnection;
return 0;
}
// Set the timeout appropriately
TimeValue timeout_time;
if (timeout_usec != UINT32_MAX)
{
timeout_time = TimeValue::Now();
timeout_time.OffsetWithMicroSeconds (timeout_usec);
}
Listener listener ("Communication::Read");
listener.StartListeningForEvents (this, eBroadcastBitReadThreadGotBytes | eBroadcastBitReadThreadDidExit);
EventSP event_sp;
while (listener.WaitForEvent (timeout_time.IsValid() ? &timeout_time : NULL, event_sp))
{
const uint32_t event_type = event_sp->GetType();
if (event_type & eBroadcastBitReadThreadGotBytes)
{
return GetCachedBytes (dst, dst_len);
}
if (event_type & eBroadcastBitReadThreadDidExit)
{
Disconnect (NULL);
break;
}
}
return 0;
}
// We aren't using a read thread, just read the data synchronously in this
// thread.
lldb::ConnectionSP connection_sp (m_connection_sp);
if (connection_sp.get())
{
status = connection_sp->BytesAvailable (timeout_usec, error_ptr);
if (status == eConnectionStatusSuccess)
return connection_sp->Read (dst, dst_len, status, error_ptr);
}
if (error_ptr)
error_ptr->SetErrorString("Invalid connection.");
status = eConnectionStatusNoConnection;
return 0;
}
size_t
Communication::Write (const void *src, size_t src_len, ConnectionStatus &status, Error *error_ptr)
{
lldb::ConnectionSP connection_sp (m_connection_sp);
lldb_private::LogIfAnyCategoriesSet (LIBLLDB_LOG_COMMUNICATION,
"%p Communication::Write (src = %p, src_len = %zu) connection = %p",
this,
src,
src_len,
connection_sp.get());
if (connection_sp.get())
return connection_sp->Write (src, src_len, status, error_ptr);
if (error_ptr)
error_ptr->SetErrorString("Invalid connection.");
status = eConnectionStatusNoConnection;
return 0;
}
bool
Communication::StartReadThread (Error *error_ptr)
{
if (m_read_thread != LLDB_INVALID_HOST_THREAD)
return true;
lldb_private::LogIfAnyCategoriesSet (LIBLLDB_LOG_COMMUNICATION,
"%p Communication::StartReadThread ()", this);
char thread_name[1024];
snprintf(thread_name, sizeof(thread_name), "<lldb.comm.%s>", m_broadcaster_name.AsCString());
m_read_thread_enabled = true;
m_read_thread = Host::ThreadCreate (thread_name, Communication::ReadThread, this, error_ptr);
if (m_read_thread == LLDB_INVALID_HOST_THREAD)
m_read_thread_enabled = false;
return m_read_thread_enabled;
}
bool
Communication::StopReadThread (Error *error_ptr)
{
if (m_read_thread == LLDB_INVALID_HOST_THREAD)
return true;
lldb_private::LogIfAnyCategoriesSet (LIBLLDB_LOG_COMMUNICATION,
"%p Communication::StopReadThread ()", this);
m_read_thread_enabled = false;
BroadcastEvent (eBroadcastBitReadThreadShouldExit, NULL);
Host::ThreadCancel (m_read_thread, error_ptr);
return Host::ThreadJoin (m_read_thread, NULL, error_ptr);
m_read_thread = LLDB_INVALID_HOST_THREAD;
}
size_t
Communication::GetCachedBytes (void *dst, size_t dst_len)
{
Mutex::Locker locker(m_bytes_mutex);
if (m_bytes.size() > 0)
{
// If DST is NULL and we have a thread, then return the number
// of bytes that are available so the caller can call again
if (dst == NULL)
return m_bytes.size();
const size_t len = std::min<size_t>(dst_len, m_bytes.size());
::memcpy (dst, m_bytes.c_str(), len);
m_bytes.erase(m_bytes.begin(), m_bytes.begin() + len);
return len;
}
return 0;
}
void
Communication::AppendBytesToCache (const uint8_t * bytes, size_t len, bool broadcast, ConnectionStatus status)
{
lldb_private::LogIfAnyCategoriesSet (LIBLLDB_LOG_COMMUNICATION,
"%p Communication::AppendBytesToCache (src = %p, src_len = %zu, broadcast = %i)",
this, bytes, len, broadcast);
if (bytes == NULL || len == 0)
return;
if (m_callback)
{
// If the user registered a callback, then call it and do not broadcast
m_callback (m_callback_baton, bytes, len);
}
else
{
Mutex::Locker locker(m_bytes_mutex);
m_bytes.append ((const char *)bytes, len);
if (broadcast)
BroadcastEventIfUnique (eBroadcastBitReadThreadGotBytes);
}
}
size_t
Communication::ReadFromConnection (void *dst, size_t dst_len, ConnectionStatus &status, Error *error_ptr)
{
lldb::ConnectionSP connection_sp (m_connection_sp);
if (connection_sp.get())
return connection_sp->Read (dst, dst_len, status, error_ptr);
return 0;
}
bool
Communication::ReadThreadIsRunning ()
{
return m_read_thread != LLDB_INVALID_HOST_THREAD;
}
void *
Communication::ReadThread (void *p)
{
Communication *comm = (Communication *)p;
LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_COMMUNICATION));
if (log)
log->Printf ("%p Communication::ReadThread () thread starting...", p);
uint8_t buf[1024];
Error error;
ConnectionStatus status = eConnectionStatusSuccess;
bool done = false;
while (!done && comm->m_read_thread_enabled)
{
status = comm->BytesAvailable (UINT32_MAX, &error);
if (status == eConnectionStatusSuccess)
{
size_t bytes_read = comm->ReadFromConnection (buf, sizeof(buf), status, &error);
if (bytes_read > 0)
comm->AppendBytesToCache (buf, bytes_read, true, status);
}
switch (status)
{
case eConnectionStatusSuccess:
break;
case eConnectionStatusEndOfFile:
case eConnectionStatusNoConnection: // No connection
case eConnectionStatusLostConnection: // Lost connection while connected to a valid connection
done = true;
// Fall through...
default:
case eConnectionStatusError: // Check GetError() for details
case eConnectionStatusTimedOut: // Request timed out
if (log)
error.LogIfError(log.get(), "%p Communication::BytesAvailable () => status = %i", p, status);
break;
}
}
log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_COMMUNICATION);
if (log)
log->Printf ("%p Communication::ReadThread () thread exiting...", p);
// Let clients know that this thread is exiting
comm->BroadcastEvent (eBroadcastBitReadThreadDidExit);
comm->m_read_thread = LLDB_INVALID_HOST_THREAD;
comm->Disconnect();
return NULL;
}
void
Communication::SetReadThreadBytesReceivedCallback
(
ReadThreadBytesReceived callback,
void *callback_baton
)
{
m_callback = callback;
m_callback_baton = callback_baton;
}
void
Communication::SetConnection (Connection *connection)
{
StopReadThread(NULL);
Disconnect (NULL);
m_connection_sp.reset(connection);
}
const char *
Communication::ConnectionStatusAsCString (lldb::ConnectionStatus status)
{
switch (status)
{
case eConnectionStatusSuccess: return "success";
case eConnectionStatusError: return "error";
case eConnectionStatusTimedOut: return "timed out";
case eConnectionStatusNoConnection: return "no connection";
case eConnectionStatusLostConnection: return "lost connection";
}
static char unknown_state_string[64];
snprintf(unknown_state_string, sizeof (unknown_state_string), "ConnectionStatus = %i", status);
return unknown_state_string;
}
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