1 //===-- AppleGetItemInfoHandler.h ----------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLDB_SOURCE_PLUGINS_SYSTEMRUNTIME_MACOSX_APPLEGETITEMINFOHANDLER_H
10 #define LLDB_SOURCE_PLUGINS_SYSTEMRUNTIME_MACOSX_APPLEGETITEMINFOHANDLER_H
11 
12 #include <map>
13 #include <mutex>
14 #include <vector>
15 
16 #include "lldb/Expression/UtilityFunction.h"
17 #include "lldb/Symbol/CompilerType.h"
18 #include "lldb/Utility/Status.h"
19 #include "lldb/lldb-public.h"
20 
21 // This class will insert a UtilityFunction into the inferior process for
22 // calling libBacktraceRecording's
23 // __introspection_dispatch_queue_item_get_info()
24 // function.  The function in the inferior will return a struct by value
25 // with these members:
26 //
27 //     struct get_item_info_return_values
28 //     {
29 //         introspection_dispatch_item_info_ref *item_buffer;
30 //         uint64_t item_buffer_size;
31 //     };
32 //
33 // The item_buffer pointer is an address in the inferior program's address
34 // space (item_buffer_size in size) which must be mach_vm_deallocate'd by
35 // lldb.
36 //
37 // The AppleGetItemInfoHandler object should persist so that the UtilityFunction
38 // can be reused multiple times.
39 
40 namespace lldb_private {
41 
42 class AppleGetItemInfoHandler {
43 public:
44   AppleGetItemInfoHandler(lldb_private::Process *process);
45 
46   ~AppleGetItemInfoHandler();
47 
48   struct GetItemInfoReturnInfo {
49     lldb::addr_t item_buffer_ptr = LLDB_INVALID_ADDRESS; /* the address of the
50                                      item buffer from libBacktraceRecording */
51     lldb::addr_t item_buffer_size = 0; /* the size of the item buffer from
52                                       libBacktraceRecording */
53 
54     GetItemInfoReturnInfo() = default;
55   };
56 
57   /// Get the information about a work item by calling
58   /// __introspection_dispatch_queue_item_get_info.  If there's a page of
59   /// memory that needs to be freed, pass in the address and size and it will
60   /// be freed before getting the list of queues.
61   ///
62   /// \param [in] thread
63   ///     The thread to run this plan on.
64   ///
65   /// \param [in] item
66   ///     The introspection_dispatch_item_info_ref value for the item of
67   ///     interest.
68   ///
69   /// \param [in] page_to_free
70   ///     An address of an inferior process vm page that needs to be
71   ///     deallocated,
72   ///     LLDB_INVALID_ADDRESS if this is not needed.
73   ///
74   /// \param [in] page_to_free_size
75   ///     The size of the vm page that needs to be deallocated if an address was
76   ///     passed in to page_to_free.
77   ///
78   /// \param [out] error
79   ///     This object will be updated with the error status / error string from
80   ///     any failures encountered.
81   ///
82   /// \returns
83   ///     The result of the inferior function call execution.  If there was a
84   ///     failure of any kind while getting
85   ///     the information, the item_buffer_ptr value will be
86   ///     LLDB_INVALID_ADDRESS.
87   GetItemInfoReturnInfo GetItemInfo(Thread &thread, lldb::addr_t item,
88                                     lldb::addr_t page_to_free,
89                                     uint64_t page_to_free_size,
90                                     lldb_private::Status &error);
91 
92   void Detach();
93 
94 private:
95   lldb::addr_t SetupGetItemInfoFunction(Thread &thread,
96                                         ValueList &get_item_info_arglist);
97 
98   static const char *g_get_item_info_function_name;
99   static const char *g_get_item_info_function_code;
100 
101   lldb_private::Process *m_process;
102   std::unique_ptr<UtilityFunction> m_get_item_info_impl_code;
103   std::mutex m_get_item_info_function_mutex;
104 
105   lldb::addr_t m_get_item_info_return_buffer_addr;
106   std::mutex m_get_item_info_retbuffer_mutex;
107 };
108 
109 } // using namespace lldb_private
110 
111 #endif // LLDB_SOURCE_PLUGINS_SYSTEMRUNTIME_MACOSX_APPLEGETITEMINFOHANDLER_H
112