Implementing plugins that provide commands.

This checkin adds the capability for LLDB to load plugins from external dylibs that can provide new commands
It exports an SBCommand class from the public API layer, and a new SBCommandPluginInterface

There is a minimal load-only plugin manager built into the debugger, which can be accessed via Debugger::LoadPlugin.

Plugins are loaded from two locations at debugger startup (LLDB.framework/Resources/PlugIns and ~/Library/Application Support/LLDB/PlugIns) and more can be (re)loaded via the "plugin load" command

For an example of how to make a plugin, refer to the fooplugin.cpp file in examples/plugins/commands

Caveats:
	Currently, the new API objects and features are not exposed via Python.
	The new commands can only be "parsed" (i.e. not raw) and get their command line via a char** parameter (we do not expose our internal Args object)
	There is no unloading feature, which can potentially lead to leaks if you overwrite the commands by reloading the same or different plugins
	There is no API exposed for option parsing, which means you may need to use getopt or roll-your-own

llvm-svn: 164865

1 files changed, 107 insertions, 0 deletions

diff --git a/lldb/source/Core/Debugger.cpp b/lldb/source/Core/Debugger.cpp
index b6e4f811062..86b0cf53e3c 100644
--- a/lldb/source/Core/Debugger.cpp
+++ b/lldb/source/Core/Debugger.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "lldb/API/SBDebugger.h"
+
 #include "lldb/Core/Debugger.h"
 
 #include <map>
@@ -28,6 +30,7 @@
 #include "lldb/Core/Timer.h"
 #include "lldb/Core/ValueObject.h"
 #include "lldb/Core/ValueObjectVariable.h"
+#include "lldb/Host/DynamicLibrary.h"
 #include "lldb/Host/Terminal.h"
 #include "lldb/Interpreter/CommandInterpreter.h"
 #include "lldb/Interpreter/OptionValueSInt64.h"
@@ -334,6 +337,109 @@ Debugger::SettingsTerminate ()
     Target::SettingsTerminate ();
 }
 
+bool
+Debugger::LoadPlugin (const FileSpec& spec)
+{
+    lldb::DynamicLibrarySP dynlib_sp(new lldb_private::DynamicLibrary(spec));
+    lldb::DebuggerSP debugger_sp(shared_from_this());
+    lldb::SBDebugger debugger_sb(debugger_sp);
+    // TODO: mangle this differently for your system - on OSX, the first underscore needs to be removed and the second one stays
+    LLDBCommandPluginInit init_func = dynlib_sp->GetSymbol<LLDBCommandPluginInit>("_ZN4lldb16PluginInitializeENS_10SBDebuggerE");
+    if (!init_func)
+        return false;
+    if (init_func(debugger_sb))
+    {
+        m_loaded_plugins.push_back(dynlib_sp);
+        return true;
+    }
+    return false;
+}
+
+static FileSpec::EnumerateDirectoryResult
+LoadPluginCallback
+(
+ void *baton,
+ FileSpec::FileType file_type,
+ const FileSpec &file_spec
+ )
+{
+    Error error;
+    
+    static ConstString g_dylibext("dylib");
+    
+    if (!baton)
+        return FileSpec::eEnumerateDirectoryResultQuit;
+    
+    Debugger *debugger = (Debugger*)baton;
+    
+    // If we have a regular file, a symbolic link or unknown file type, try
+    // and process the file. We must handle unknown as sometimes the directory
+    // enumeration might be enumerating a file system that doesn't have correct
+    // file type information.
+    if (file_type == FileSpec::eFileTypeRegular         ||
+        file_type == FileSpec::eFileTypeSymbolicLink    ||
+        file_type == FileSpec::eFileTypeUnknown          )
+    {
+        FileSpec plugin_file_spec (file_spec);
+        plugin_file_spec.ResolvePath ();
+        
+        if (plugin_file_spec.GetFileNameExtension() != g_dylibext)
+            return FileSpec::eEnumerateDirectoryResultNext;
+
+        debugger->LoadPlugin (plugin_file_spec);
+        
+        return FileSpec::eEnumerateDirectoryResultNext;
+    }
+    
+    else if (file_type == FileSpec::eFileTypeUnknown     ||
+        file_type == FileSpec::eFileTypeDirectory   ||
+        file_type == FileSpec::eFileTypeSymbolicLink )
+    {
+        // Try and recurse into anything that a directory or symbolic link.
+        // We must also do this for unknown as sometimes the directory enumeration
+        // might be enurating a file system that doesn't have correct file type
+        // information.
+        return FileSpec::eEnumerateDirectoryResultEnter;
+    }
+    
+    return FileSpec::eEnumerateDirectoryResultNext;
+}
+
+void
+Debugger::InstanceInitialize ()
+{
+    FileSpec dir_spec;
+    const bool find_directories = true;
+    const bool find_files = true;
+    const bool find_other = true;
+    char dir_path[PATH_MAX];
+    if (Host::GetLLDBPath (ePathTypeLLDBSystemPlugins, dir_spec))
+    {
+        if (dir_spec.Exists() && dir_spec.GetPath(dir_path, sizeof(dir_path)))
+        {
+            FileSpec::EnumerateDirectory (dir_path,
+                                          find_directories,
+                                          find_files,
+                                          find_other,
+                                          LoadPluginCallback,
+                                          this);
+        }
+    }
+    
+    if (Host::GetLLDBPath (ePathTypeLLDBUserPlugins, dir_spec))
+    {
+        if (dir_spec.Exists() && dir_spec.GetPath(dir_path, sizeof(dir_path)))
+        {
+            FileSpec::EnumerateDirectory (dir_path,
+                                          find_directories,
+                                          find_files,
+                                          find_other,
+                                          LoadPluginCallback,
+                                          this);
+        }
+    }
+}
+
 DebuggerSP
 Debugger::CreateInstance (lldb::LogOutputCallback log_callback, void *baton)
 {
@@ -343,6 +449,7 @@ Debugger::CreateInstance (lldb::LogOutputCallback log_callback, void *baton)
         Mutex::Locker locker (GetDebuggerListMutex ());
         GetDebuggerList().push_back(debugger_sp);
     }
+    debugger_sp->InstanceInitialize ();
     return debugger_sp;
 }