contrib/llvm-project/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTrampolineHandler.cpp

   1 //===-- AppleObjCTrampolineHandler.cpp ----------------------------*- C++
   2 //-*-===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "AppleObjCTrampolineHandler.h"
  11 #include "AppleThreadPlanStepThroughObjCTrampoline.h"
  12
  13 #include "lldb/Breakpoint/StoppointCallbackContext.h"
  14 #include "lldb/Core/Debugger.h"
  15 #include "lldb/Core/Module.h"
  16 #include "lldb/Core/StreamFile.h"
  17 #include "lldb/Core/Value.h"
  18 #include "lldb/Expression/DiagnosticManager.h"
  19 #include "lldb/Expression/FunctionCaller.h"
  20 #include "lldb/Expression/UserExpression.h"
  21 #include "lldb/Expression/UtilityFunction.h"
  22 #include "lldb/Symbol/ClangASTContext.h"
  23 #include "lldb/Symbol/Symbol.h"
  24 #include "lldb/Target/ABI.h"
  25 #include "lldb/Target/ExecutionContext.h"
  26 #include "lldb/Target/Process.h"
  27 #include "lldb/Target/RegisterContext.h"
  28 #include "lldb/Target/Target.h"
  29 #include "lldb/Target/Thread.h"
  30 #include "lldb/Target/ThreadPlanRunToAddress.h"
  31 #include "lldb/Utility/ConstString.h"
  32 #include "lldb/Utility/FileSpec.h"
  33 #include "lldb/Utility/Log.h"
  34
  35 #include "llvm/ADT/STLExtras.h"
  36
  37 #include "Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h"
  38
  39 #include <memory>
  40
  41 using namespace lldb;
  42 using namespace lldb_private;
  43
  44 const char *AppleObjCTrampolineHandler::g_lookup_implementation_function_name =
  45     "__lldb_objc_find_implementation_for_selector";
  46 const char *AppleObjCTrampolineHandler::
  47     g_lookup_implementation_with_stret_function_code =
  48         "                               \n\
  49 extern \"C\"                                                                 \n\
  50 {                                                                            \n\
  51     extern void *class_getMethodImplementation(void *objc_class, void *sel); \n\
  52     extern void *class_getMethodImplementation_stret(void *objc_class,       \n\
  53                                                      void *sel);             \n\
  54     extern void * object_getClass (id object);                               \n\
  55     extern void * sel_getUid(char *name);                                    \n\
  56     extern int printf(const char *format, ...);                              \n\
  57 }                                                                            \n\
  58 extern \"C\" void * __lldb_objc_find_implementation_for_selector (           \n\
  59                                                     void *object,            \n\
  60                                                     void *sel,               \n\
  61                                                     int is_stret,            \n\
  62                                                     int is_super,            \n\
  63                                                     int is_super2,           \n\
  64                                                     int is_fixup,            \n\
  65                                                     int is_fixed,            \n\
  66                                                     int debug)               \n\
  67 {                                                                            \n\
  68     struct __lldb_imp_return_struct                                          \n\
  69     {                                                                        \n\
  70         void *class_addr;                                                    \n\
  71         void *sel_addr;                                                      \n\
  72         void *impl_addr;                                                     \n\
  73     };                                                                       \n\
  74                                                                              \n\
  75     struct __lldb_objc_class {                                               \n\
  76         void *isa;                                                           \n\
  77         void *super_ptr;                                                     \n\
  78     };                                                                       \n\
  79     struct __lldb_objc_super {                                               \n\
  80         void *receiver;                                                      \n\
  81         struct __lldb_objc_class *class_ptr;                                 \n\
  82     };                                                                       \n\
  83     struct __lldb_msg_ref {                                                  \n\
  84         void *dont_know;                                                     \n\
  85         void *sel;                                                           \n\
  86     };                                                                       \n\
  87                                                                              \n\
  88     struct __lldb_imp_return_struct return_struct;                           \n\
  89                                                                              \n\
  90     if (debug)                                                               \n\
  91         printf (\"\\n*** Called with obj: 0x%p sel: 0x%p is_stret: %d is_super: %d, \"\n\
  92                 \"is_super2: %d, is_fixup: %d, is_fixed: %d\\n\",            \n\
  93                  object, sel, is_stret, is_super, is_super2, is_fixup, is_fixed);\n\
  94     if (is_super)                                                            \n\
  95     {                                                                        \n\
  96         if (is_super2)                                                       \n\
  97         {                                                                    \n\
  98             return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr->super_ptr;\n\
  99         }                                                                    \n\
 100         else                                                                 \n\
 101         {                                                                    \n\
 102             return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr;\n\
 103         }                                                                    \n\
 104     }                                                                        \n\
 105     else                                                                     \n\
 106     {                                                                        \n\
 107         // This code seems a little funny, but has its reasons...            \n\
 108                                                                              \n\
 109         // The call to [object class] is here because if this is a           \n\
 110         // class, and has not been called into yet, we need to do            \n\
 111         // something to force the class to initialize itself.                \n\
 112         // Then the call to object_getClass will actually return the         \n\
 113         // correct class, either the class if object is a class              \n\
 114         // instance, or the meta-class if it is a class pointer.             \n\
 115         void *class_ptr = (void *) [(id) object class];                      \n\
 116         return_struct.class_addr = (id)  object_getClass((id) object);       \n\
 117         if (debug)                                                           \n\
 118         {                                                                    \n\
 119             if (class_ptr == object)                                         \n\
 120             {                                                                \n\
 121                 printf (\"Found a class object, need to use the meta class %p -> %p\\n\",\n\
 122                         class_ptr, return_struct.class_addr);                \n\
 123             }                                                                \n\
 124             else                                                             \n\
 125             {                                                                \n\
 126                  printf (\"[object class] returned: %p object_getClass: %p.\\n\", \n\
 127                  class_ptr, return_struct.class_addr);                       \n\
 128             }                                                                \n\
 129         }                                                                    \n\
 130     }                                                                        \n\
 131                                                                              \n\
 132     if (is_fixup)                                                            \n\
 133     {                                                                        \n\
 134         if (is_fixed)                                                        \n\
 135         {                                                                    \n\
 136             return_struct.sel_addr = ((__lldb_msg_ref *) sel)->sel;          \n\
 137         }                                                                    \n\
 138         else                                                                 \n\
 139         {                                                                    \n\
 140             char *sel_name = (char *) ((__lldb_msg_ref *) sel)->sel;         \n\
 141             return_struct.sel_addr = sel_getUid (sel_name);                  \n\
 142             if (debug)                                                       \n\
 143                 printf (\"\\n*** Got fixed up selector: %p for name %s.\\n\",\n\
 144                         return_struct.sel_addr, sel_name);                   \n\
 145         }                                                                    \n\
 146     }                                                                        \n\
 147     else                                                                     \n\
 148     {                                                                        \n\
 149         return_struct.sel_addr = sel;                                        \n\
 150     }                                                                        \n\
 151                                                                              \n\
 152     if (is_stret)                                                            \n\
 153     {                                                                        \n\
 154         return_struct.impl_addr =                                            \n\
 155           class_getMethodImplementation_stret (return_struct.class_addr,     \n\
 156                                                return_struct.sel_addr);      \n\
 157     }                                                                        \n\
 158     else                                                                     \n\
 159     {                                                                        \n\
 160         return_struct.impl_addr =                                            \n\
 161             class_getMethodImplementation (return_struct.class_addr,         \n\
 162                                            return_struct.sel_addr);          \n\
 163     }                                                                        \n\
 164     if (debug)                                                               \n\
 165         printf (\"\\n*** Returning implementation: %p.\\n\",                 \n\
 166                           return_struct.impl_addr);                          \n\
 167                                                                              \n\
 168     return return_struct.impl_addr;                                          \n\
 169 }                                                                            \n\
 170 ";
 171 const char *
 172     AppleObjCTrampolineHandler::g_lookup_implementation_no_stret_function_code =
 173         "                      \n\
 174 extern \"C\"                                                                 \n\
 175 {                                                                            \n\
 176     extern void *class_getMethodImplementation(void *objc_class, void *sel); \n\
 177     extern void * object_getClass (id object);                               \n\
 178     extern void * sel_getUid(char *name);                                    \n\
 179     extern int printf(const char *format, ...);                              \n\
 180 }                                                                            \n\
 181 extern \"C\" void * __lldb_objc_find_implementation_for_selector (void *object,                                 \n\
 182                                                     void *sel,               \n\
 183                                                     int is_stret,            \n\
 184                                                     int is_super,            \n\
 185                                                     int is_super2,           \n\
 186                                                     int is_fixup,            \n\
 187                                                     int is_fixed,            \n\
 188                                                     int debug)               \n\
 189 {                                                                            \n\
 190     struct __lldb_imp_return_struct                                          \n\
 191     {                                                                        \n\
 192         void *class_addr;                                                    \n\
 193         void *sel_addr;                                                      \n\
 194         void *impl_addr;                                                     \n\
 195     };                                                                       \n\
 196                                                                              \n\
 197     struct __lldb_objc_class {                                               \n\
 198         void *isa;                                                           \n\
 199         void *super_ptr;                                                     \n\
 200     };                                                                       \n\
 201     struct __lldb_objc_super {                                               \n\
 202         void *receiver;                                                      \n\
 203         struct __lldb_objc_class *class_ptr;                                 \n\
 204     };                                                                       \n\
 205     struct __lldb_msg_ref {                                                  \n\
 206         void *dont_know;                                                     \n\
 207         void *sel;                                                           \n\
 208     };                                                                       \n\
 209                                                                              \n\
 210     struct __lldb_imp_return_struct return_struct;                           \n\
 211                                                                              \n\
 212     if (debug)                                                               \n\
 213         printf (\"\\n*** Called with obj: 0x%p sel: 0x%p is_stret: %d is_super: %d, \"                          \n\
 214                 \"is_super2: %d, is_fixup: %d, is_fixed: %d\\n\",            \n\
 215                  object, sel, is_stret, is_super, is_super2, is_fixup, is_fixed);                               \n\
 216     if (is_super)                                                            \n\
 217     {                                                                        \n\
 218         if (is_super2)                                                       \n\
 219         {                                                                    \n\
 220             return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr->super_ptr;                    \n\
 221         }                                                                    \n\
 222         else                                                                 \n\
 223         {                                                                    \n\
 224             return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr;                               \n\
 225         }                                                                    \n\
 226     }                                                                        \n\
 227     else                                                                     \n\
 228     {                                                                        \n\
 229         // This code seems a little funny, but has its reasons...            \n\
 230         // The call to [object class] is here because if this is a class, and has not been called into          \n\
 231         // yet, we need to do something to force the class to initialize itself.                                \n\
 232         // Then the call to object_getClass will actually return the correct class, either the class            \n\
 233         // if object is a class instance, or the meta-class if it is a class pointer.                           \n\
 234         void *class_ptr = (void *) [(id) object class];                      \n\
 235         return_struct.class_addr = (id)  object_getClass((id) object);       \n\
 236         if (debug)                                                           \n\
 237         {                                                                    \n\
 238             if (class_ptr == object)                                         \n\
 239             {                                                                \n\
 240                 printf (\"Found a class object, need to return the meta class %p -> %p\\n\",                    \n\
 241                         class_ptr, return_struct.class_addr);                \n\
 242             }                                                                \n\
 243             else                                                             \n\
 244             {                                                                \n\
 245                  printf (\"[object class] returned: %p object_getClass: %p.\\n\",                               \n\
 246                  class_ptr, return_struct.class_addr);                       \n\
 247             }                                                                \n\
 248         }                                                                    \n\
 249     }                                                                        \n\
 250                                                                              \n\
 251     if (is_fixup)                                                            \n\
 252     {                                                                        \n\
 253         if (is_fixed)                                                        \n\
 254         {                                                                    \n\
 255             return_struct.sel_addr = ((__lldb_msg_ref *) sel)->sel;          \n\
 256         }                                                                    \n\
 257         else                                                                 \n\
 258         {                                                                    \n\
 259             char *sel_name = (char *) ((__lldb_msg_ref *) sel)->sel;         \n\
 260             return_struct.sel_addr = sel_getUid (sel_name);                  \n\
 261             if (debug)                                                       \n\
 262                 printf (\"\\n*** Got fixed up selector: %p for name %s.\\n\",\n\
 263                         return_struct.sel_addr, sel_name);                   \n\
 264         }                                                                    \n\
 265     }                                                                        \n\
 266     else                                                                     \n\
 267     {                                                                        \n\
 268         return_struct.sel_addr = sel;                                        \n\
 269     }                                                                        \n\
 270                                                                              \n\
 271     return_struct.impl_addr =                                                \n\
 272       class_getMethodImplementation (return_struct.class_addr,               \n\
 273                                      return_struct.sel_addr);                \n\
 274     if (debug)                                                               \n\
 275         printf (\"\\n*** Returning implementation: 0x%p.\\n\",               \n\
 276           return_struct.impl_addr);                                          \n\
 277                                                                              \n\
 278     return return_struct.impl_addr;                                          \n\
 279 }                                                                            \n\
 280 ";
 281
 282 AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::VTableRegion(
 283     AppleObjCVTables *owner, lldb::addr_t header_addr)
 284     : m_valid(true), m_owner(owner), m_header_addr(header_addr),
 285       m_code_start_addr(0), m_code_end_addr(0), m_next_region(0) {
 286   SetUpRegion();
 287 }
 288
 289 AppleObjCTrampolineHandler::~AppleObjCTrampolineHandler() {}
 290
 291 void AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::SetUpRegion() {
 292   // The header looks like:
 293   //
 294   //   uint16_t headerSize
 295   //   uint16_t descSize
 296   //   uint32_t descCount
 297   //   void * next
 298   //
 299   // First read in the header:
 300
 301   char memory_buffer[16];
 302   ProcessSP process_sp = m_owner->GetProcessSP();
 303   if (!process_sp)
 304     return;
 305   DataExtractor data(memory_buffer, sizeof(memory_buffer),
 306                      process_sp->GetByteOrder(),
 307                      process_sp->GetAddressByteSize());
 308   size_t actual_size = 8 + process_sp->GetAddressByteSize();
 309   Status error;
 310   size_t bytes_read =
 311       process_sp->ReadMemory(m_header_addr, memory_buffer, actual_size, error);
 312   if (bytes_read != actual_size) {
 313     m_valid = false;
 314     return;
 315   }
 316
 317   lldb::offset_t offset = 0;
 318   const uint16_t header_size = data.GetU16(&offset);
 319   const uint16_t descriptor_size = data.GetU16(&offset);
 320   const size_t num_descriptors = data.GetU32(&offset);
 321
 322   m_next_region = data.GetPointer(&offset);
 323
 324   // If the header size is 0, that means we've come in too early before this
 325   // data is set up.
 326   // Set ourselves as not valid, and continue.
 327   if (header_size == 0 || num_descriptors == 0) {
 328     m_valid = false;
 329     return;
 330   }
 331
 332   // Now read in all the descriptors:
 333   // The descriptor looks like:
 334   //
 335   // uint32_t offset
 336   // uint32_t flags
 337   //
 338   // Where offset is either 0 - in which case it is unused, or it is
 339   // the offset of the vtable code from the beginning of the
 340   // descriptor record.  Below, we'll convert that into an absolute
 341   // code address, since I don't want to have to compute it over and
 342   // over.
 343
 344   // Ingest the whole descriptor array:
 345   const lldb::addr_t desc_ptr = m_header_addr + header_size;
 346   const size_t desc_array_size = num_descriptors * descriptor_size;
 347   DataBufferSP data_sp(new DataBufferHeap(desc_array_size, '\0'));
 348   uint8_t *dst = (uint8_t *)data_sp->GetBytes();
 349
 350   DataExtractor desc_extractor(dst, desc_array_size, process_sp->GetByteOrder(),
 351                                process_sp->GetAddressByteSize());
 352   bytes_read = process_sp->ReadMemory(desc_ptr, dst, desc_array_size, error);
 353   if (bytes_read != desc_array_size) {
 354     m_valid = false;
 355     return;
 356   }
 357
 358   // The actual code for the vtables will be laid out consecutively, so I also
 359   // compute the start and end of the whole code block.
 360
 361   offset = 0;
 362   m_code_start_addr = 0;
 363   m_code_end_addr = 0;
 364
 365   for (size_t i = 0; i < num_descriptors; i++) {
 366     lldb::addr_t start_offset = offset;
 367     uint32_t voffset = desc_extractor.GetU32(&offset);
 368     uint32_t flags = desc_extractor.GetU32(&offset);
 369     lldb::addr_t code_addr = desc_ptr + start_offset + voffset;
 370     m_descriptors.push_back(VTableDescriptor(flags, code_addr));
 371
 372     if (m_code_start_addr == 0 || code_addr < m_code_start_addr)
 373       m_code_start_addr = code_addr;
 374     if (code_addr > m_code_end_addr)
 375       m_code_end_addr = code_addr;
 376
 377     offset = start_offset + descriptor_size;
 378   }
 379   // Finally, a little bird told me that all the vtable code blocks
 380   // are the same size.  Let's compute the blocks and if they are all
 381   // the same add the size to the code end address:
 382   lldb::addr_t code_size = 0;
 383   bool all_the_same = true;
 384   for (size_t i = 0; i < num_descriptors - 1; i++) {
 385     lldb::addr_t this_size =
 386         m_descriptors[i + 1].code_start - m_descriptors[i].code_start;
 387     if (code_size == 0)
 388       code_size = this_size;
 389     else {
 390       if (this_size != code_size)
 391         all_the_same = false;
 392       if (this_size > code_size)
 393         code_size = this_size;
 394     }
 395   }
 396   if (all_the_same)
 397     m_code_end_addr += code_size;
 398 }
 399
 400 bool AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::
 401     AddressInRegion(lldb::addr_t addr, uint32_t &flags) {
 402   if (!IsValid())
 403     return false;
 404
 405   if (addr < m_code_start_addr || addr > m_code_end_addr)
 406     return false;
 407
 408   std::vector<VTableDescriptor>::iterator pos, end = m_descriptors.end();
 409   for (pos = m_descriptors.begin(); pos != end; pos++) {
 410     if (addr <= (*pos).code_start) {
 411       flags = (*pos).flags;
 412       return true;
 413     }
 414   }
 415   return false;
 416 }
 417
 418 void AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::Dump(
 419     Stream &s) {
 420   s.Printf("Header addr: 0x%" PRIx64 " Code start: 0x%" PRIx64
 421            " Code End: 0x%" PRIx64 " Next: 0x%" PRIx64 "\n",
 422            m_header_addr, m_code_start_addr, m_code_end_addr, m_next_region);
 423   size_t num_elements = m_descriptors.size();
 424   for (size_t i = 0; i < num_elements; i++) {
 425     s.Indent();
 426     s.Printf("Code start: 0x%" PRIx64 " Flags: %d\n",
 427              m_descriptors[i].code_start, m_descriptors[i].flags);
 428   }
 429 }
 430
 431 AppleObjCTrampolineHandler::AppleObjCVTables::AppleObjCVTables(
 432     const ProcessSP &process_sp, const ModuleSP &objc_module_sp)
 433     : m_process_wp(), m_trampoline_header(LLDB_INVALID_ADDRESS),
 434       m_trampolines_changed_bp_id(LLDB_INVALID_BREAK_ID),
 435       m_objc_module_sp(objc_module_sp) {
 436   if (process_sp)
 437     m_process_wp = process_sp;
 438 }
 439
 440 AppleObjCTrampolineHandler::AppleObjCVTables::~AppleObjCVTables() {
 441   ProcessSP process_sp = GetProcessSP();
 442   if (process_sp) {
 443     if (m_trampolines_changed_bp_id != LLDB_INVALID_BREAK_ID)
 444       process_sp->GetTarget().RemoveBreakpointByID(m_trampolines_changed_bp_id);
 445   }
 446 }
 447
 448 bool AppleObjCTrampolineHandler::AppleObjCVTables::InitializeVTableSymbols() {
 449   if (m_trampoline_header != LLDB_INVALID_ADDRESS)
 450     return true;
 451
 452   ProcessSP process_sp = GetProcessSP();
 453   if (process_sp) {
 454     Target &target = process_sp->GetTarget();
 455
 456     const ModuleList &target_modules = target.GetImages();
 457     std::lock_guard<std::recursive_mutex> guard(target_modules.GetMutex());
 458     size_t num_modules = target_modules.GetSize();
 459     if (!m_objc_module_sp) {
 460       for (size_t i = 0; i < num_modules; i++) {
 461         if (ObjCLanguageRuntime::Get(*process_sp)
 462                 ->IsModuleObjCLibrary(
 463                     target_modules.GetModuleAtIndexUnlocked(i))) {
 464           m_objc_module_sp = target_modules.GetModuleAtIndexUnlocked(i);
 465           break;
 466         }
 467       }
 468     }
 469
 470     if (m_objc_module_sp) {
 471       ConstString trampoline_name("gdb_objc_trampolines");
 472       const Symbol *trampoline_symbol =
 473           m_objc_module_sp->FindFirstSymbolWithNameAndType(trampoline_name,
 474                                                            eSymbolTypeData);
 475       if (trampoline_symbol != nullptr) {
 476         m_trampoline_header = trampoline_symbol->GetLoadAddress(&target);
 477         if (m_trampoline_header == LLDB_INVALID_ADDRESS)
 478           return false;
 479
 480         // Next look up the "changed" symbol and set a breakpoint on that...
 481         ConstString changed_name("gdb_objc_trampolines_changed");
 482         const Symbol *changed_symbol =
 483             m_objc_module_sp->FindFirstSymbolWithNameAndType(changed_name,
 484                                                              eSymbolTypeCode);
 485         if (changed_symbol != nullptr) {
 486           const Address changed_symbol_addr = changed_symbol->GetAddress();
 487           if (!changed_symbol_addr.IsValid())
 488             return false;
 489
 490           lldb::addr_t changed_addr =
 491               changed_symbol_addr.GetOpcodeLoadAddress(&target);
 492           if (changed_addr != LLDB_INVALID_ADDRESS) {
 493             BreakpointSP trampolines_changed_bp_sp =
 494                 target.CreateBreakpoint(changed_addr, true, false);
 495             if (trampolines_changed_bp_sp) {
 496               m_trampolines_changed_bp_id = trampolines_changed_bp_sp->GetID();
 497               trampolines_changed_bp_sp->SetCallback(RefreshTrampolines, this,
 498                                                      true);
 499               trampolines_changed_bp_sp->SetBreakpointKind(
 500                   "objc-trampolines-changed");
 501               return true;
 502             }
 503           }
 504         }
 505       }
 506     }
 507   }
 508   return false;
 509 }
 510
 511 bool AppleObjCTrampolineHandler::AppleObjCVTables::RefreshTrampolines(
 512     void *baton, StoppointCallbackContext *context, lldb::user_id_t break_id,
 513     lldb::user_id_t break_loc_id) {
 514   AppleObjCVTables *vtable_handler = (AppleObjCVTables *)baton;
 515   if (vtable_handler->InitializeVTableSymbols()) {
 516     // The Update function is called with the address of an added region.  So we
 517     // grab that address, and
 518     // feed it into ReadRegions.  Of course, our friend the ABI will get the
 519     // values for us.
 520     ExecutionContext exe_ctx(context->exe_ctx_ref);
 521     Process *process = exe_ctx.GetProcessPtr();
 522     const ABI *abi = process->GetABI().get();
 523
 524     ClangASTContext *clang_ast_context =
 525         process->GetTarget().GetScratchClangASTContext();
 526     ValueList argument_values;
 527     Value input_value;
 528     CompilerType clang_void_ptr_type =
 529         clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
 530
 531     input_value.SetValueType(Value::eValueTypeScalar);
 532     // input_value.SetContext (Value::eContextTypeClangType,
 533     // clang_void_ptr_type);
 534     input_value.SetCompilerType(clang_void_ptr_type);
 535     argument_values.PushValue(input_value);
 536
 537     bool success =
 538         abi->GetArgumentValues(exe_ctx.GetThreadRef(), argument_values);
 539     if (!success)
 540       return false;
 541
 542     // Now get a pointer value from the zeroth argument.
 543     Status error;
 544     DataExtractor data;
 545     error = argument_values.GetValueAtIndex(0)->GetValueAsData(&exe_ctx, data,
 546                                                                0, nullptr);
 547     lldb::offset_t offset = 0;
 548     lldb::addr_t region_addr = data.GetPointer(&offset);
 549
 550     if (region_addr != 0)
 551       vtable_handler->ReadRegions(region_addr);
 552   }
 553   return false;
 554 }
 555
 556 bool AppleObjCTrampolineHandler::AppleObjCVTables::ReadRegions() {
 557   // The no argument version reads the  start region from the value of
 558   // the gdb_regions_header, and gets started from there.
 559
 560   m_regions.clear();
 561   if (!InitializeVTableSymbols())
 562     return false;
 563   Status error;
 564   ProcessSP process_sp = GetProcessSP();
 565   if (process_sp) {
 566     lldb::addr_t region_addr =
 567         process_sp->ReadPointerFromMemory(m_trampoline_header, error);
 568     if (error.Success())
 569       return ReadRegions(region_addr);
 570   }
 571   return false;
 572 }
 573
 574 bool AppleObjCTrampolineHandler::AppleObjCVTables::ReadRegions(
 575     lldb::addr_t region_addr) {
 576   ProcessSP process_sp = GetProcessSP();
 577   if (!process_sp)
 578     return false;
 579
 580   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
 581
 582   // We aren't starting at the trampoline symbol.
 583   InitializeVTableSymbols();
 584   lldb::addr_t next_region = region_addr;
 585
 586   // Read in the sizes of the headers.
 587   while (next_region != 0) {
 588     m_regions.push_back(VTableRegion(this, next_region));
 589     if (!m_regions.back().IsValid()) {
 590       m_regions.clear();
 591       return false;
 592     }
 593     if (log) {
 594       StreamString s;
 595       m_regions.back().Dump(s);
 596       log->Printf("Read vtable region: \n%s", s.GetData());
 597     }
 598
 599     next_region = m_regions.back().GetNextRegionAddr();
 600   }
 601
 602   return true;
 603 }
 604
 605 bool AppleObjCTrampolineHandler::AppleObjCVTables::IsAddressInVTables(
 606     lldb::addr_t addr, uint32_t &flags) {
 607   region_collection::iterator pos, end = m_regions.end();
 608   for (pos = m_regions.begin(); pos != end; pos++) {
 609     if ((*pos).AddressInRegion(addr, flags))
 610       return true;
 611   }
 612   return false;
 613 }
 614
 615 const AppleObjCTrampolineHandler::DispatchFunction
 616     AppleObjCTrampolineHandler::g_dispatch_functions[] = {
 617         // NAME                              STRET  SUPER  SUPER2  FIXUP TYPE
 618         {"objc_msgSend", false, false, false, DispatchFunction::eFixUpNone},
 619         {"objc_msgSend_fixup", false, false, false,
 620          DispatchFunction::eFixUpToFix},
 621         {"objc_msgSend_fixedup", false, false, false,
 622          DispatchFunction::eFixUpFixed},
 623         {"objc_msgSend_stret", true, false, false,
 624          DispatchFunction::eFixUpNone},
 625         {"objc_msgSend_stret_fixup", true, false, false,
 626          DispatchFunction::eFixUpToFix},
 627         {"objc_msgSend_stret_fixedup", true, false, false,
 628          DispatchFunction::eFixUpFixed},
 629         {"objc_msgSend_fpret", false, false, false,
 630          DispatchFunction::eFixUpNone},
 631         {"objc_msgSend_fpret_fixup", false, false, false,
 632          DispatchFunction::eFixUpToFix},
 633         {"objc_msgSend_fpret_fixedup", false, false, false,
 634          DispatchFunction::eFixUpFixed},
 635         {"objc_msgSend_fp2ret", false, false, true,
 636          DispatchFunction::eFixUpNone},
 637         {"objc_msgSend_fp2ret_fixup", false, false, true,
 638          DispatchFunction::eFixUpToFix},
 639         {"objc_msgSend_fp2ret_fixedup", false, false, true,
 640          DispatchFunction::eFixUpFixed},
 641         {"objc_msgSendSuper", false, true, false, DispatchFunction::eFixUpNone},
 642         {"objc_msgSendSuper_stret", true, true, false,
 643          DispatchFunction::eFixUpNone},
 644         {"objc_msgSendSuper2", false, true, true, DispatchFunction::eFixUpNone},
 645         {"objc_msgSendSuper2_fixup", false, true, true,
 646          DispatchFunction::eFixUpToFix},
 647         {"objc_msgSendSuper2_fixedup", false, true, true,
 648          DispatchFunction::eFixUpFixed},
 649         {"objc_msgSendSuper2_stret", true, true, true,
 650          DispatchFunction::eFixUpNone},
 651         {"objc_msgSendSuper2_stret_fixup", true, true, true,
 652          DispatchFunction::eFixUpToFix},
 653         {"objc_msgSendSuper2_stret_fixedup", true, true, true,
 654          DispatchFunction::eFixUpFixed},
 655 };
 656
 657 AppleObjCTrampolineHandler::AppleObjCTrampolineHandler(
 658     const ProcessSP &process_sp, const ModuleSP &objc_module_sp)
 659     : m_process_wp(), m_objc_module_sp(objc_module_sp),
 660       m_lookup_implementation_function_code(nullptr),
 661       m_impl_fn_addr(LLDB_INVALID_ADDRESS),
 662       m_impl_stret_fn_addr(LLDB_INVALID_ADDRESS),
 663       m_msg_forward_addr(LLDB_INVALID_ADDRESS) {
 664   if (process_sp)
 665     m_process_wp = process_sp;
 666   // Look up the known resolution functions:
 667
 668   ConstString get_impl_name("class_getMethodImplementation");
 669   ConstString get_impl_stret_name("class_getMethodImplementation_stret");
 670   ConstString msg_forward_name("_objc_msgForward");
 671   ConstString msg_forward_stret_name("_objc_msgForward_stret");
 672
 673   Target *target = process_sp ? &process_sp->GetTarget() : nullptr;
 674   const Symbol *class_getMethodImplementation =
 675       m_objc_module_sp->FindFirstSymbolWithNameAndType(get_impl_name,
 676                                                        eSymbolTypeCode);
 677   const Symbol *class_getMethodImplementation_stret =
 678       m_objc_module_sp->FindFirstSymbolWithNameAndType(get_impl_stret_name,
 679                                                        eSymbolTypeCode);
 680   const Symbol *msg_forward = m_objc_module_sp->FindFirstSymbolWithNameAndType(
 681       msg_forward_name, eSymbolTypeCode);
 682   const Symbol *msg_forward_stret =
 683       m_objc_module_sp->FindFirstSymbolWithNameAndType(msg_forward_stret_name,
 684                                                        eSymbolTypeCode);
 685
 686   if (class_getMethodImplementation)
 687     m_impl_fn_addr =
 688         class_getMethodImplementation->GetAddress().GetOpcodeLoadAddress(
 689             target);
 690   if (class_getMethodImplementation_stret)
 691     m_impl_stret_fn_addr =
 692         class_getMethodImplementation_stret->GetAddress().GetOpcodeLoadAddress(
 693             target);
 694   if (msg_forward)
 695     m_msg_forward_addr = msg_forward->GetAddress().GetOpcodeLoadAddress(target);
 696   if (msg_forward_stret)
 697     m_msg_forward_stret_addr =
 698         msg_forward_stret->GetAddress().GetOpcodeLoadAddress(target);
 699
 700   // FIXME: Do some kind of logging here.
 701   if (m_impl_fn_addr == LLDB_INVALID_ADDRESS) {
 702     // If we can't even find the ordinary get method implementation function,
 703     // then we aren't going to be able to
 704     // step through any method dispatches.  Warn to that effect and get out of
 705     // here.
 706     if (process_sp->CanJIT()) {
 707       process_sp->GetTarget().GetDebugger().GetErrorFile()->Printf(
 708           "Could not find implementation lookup function \"%s\""
 709           " step in through ObjC method dispatch will not work.\n",
 710           get_impl_name.AsCString());
 711     }
 712     return;
 713   } else if (m_impl_stret_fn_addr == LLDB_INVALID_ADDRESS) {
 714     // It there is no stret return lookup function, assume that it is the same
 715     // as the straight lookup:
 716     m_impl_stret_fn_addr = m_impl_fn_addr;
 717     // Also we will use the version of the lookup code that doesn't rely on the
 718     // stret version of the function.
 719     m_lookup_implementation_function_code =
 720         g_lookup_implementation_no_stret_function_code;
 721   } else {
 722     m_lookup_implementation_function_code =
 723         g_lookup_implementation_with_stret_function_code;
 724   }
 725
 726   // Look up the addresses for the objc dispatch functions and cache
 727   // them.  For now I'm inspecting the symbol names dynamically to
 728   // figure out how to dispatch to them.  If it becomes more
 729   // complicated than this we can turn the g_dispatch_functions char *
 730   // array into a template table, and populate the DispatchFunction
 731   // map from there.
 732
 733   for (size_t i = 0; i != llvm::array_lengthof(g_dispatch_functions); i++) {
 734     ConstString name_const_str(g_dispatch_functions[i].name);
 735     const Symbol *msgSend_symbol =
 736         m_objc_module_sp->FindFirstSymbolWithNameAndType(name_const_str,
 737                                                          eSymbolTypeCode);
 738     if (msgSend_symbol && msgSend_symbol->ValueIsAddress()) {
 739       // FIXME: Make g_dispatch_functions static table of
 740       // DispatchFunctions, and have the map be address->index.
 741       // Problem is we also need to lookup the dispatch function.  For
 742       // now we could have a side table of stret & non-stret dispatch
 743       // functions.  If that's as complex as it gets, we're fine.
 744
 745       lldb::addr_t sym_addr =
 746           msgSend_symbol->GetAddressRef().GetOpcodeLoadAddress(target);
 747
 748       m_msgSend_map.insert(std::pair<lldb::addr_t, int>(sym_addr, i));
 749     }
 750   }
 751
 752   // Build our vtable dispatch handler here:
 753   m_vtables_up.reset(new AppleObjCVTables(process_sp, m_objc_module_sp));
 754   if (m_vtables_up)
 755     m_vtables_up->ReadRegions();
 756 }
 757
 758 lldb::addr_t
 759 AppleObjCTrampolineHandler::SetupDispatchFunction(Thread &thread,
 760                                                   ValueList &dispatch_values) {
 761   ThreadSP thread_sp(thread.shared_from_this());
 762   ExecutionContext exe_ctx(thread_sp);
 763   DiagnosticManager diagnostics;
 764   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
 765
 766   lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
 767   FunctionCaller *impl_function_caller = nullptr;
 768
 769   // Scope for mutex locker:
 770   {
 771     std::lock_guard<std::mutex> guard(m_impl_function_mutex);
 772
 773     // First stage is to make the ClangUtility to hold our injected function:
 774
 775     if (!m_impl_code) {
 776       if (m_lookup_implementation_function_code != nullptr) {
 777         Status error;
 778         m_impl_code.reset(exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage(
 779             m_lookup_implementation_function_code, eLanguageTypeObjC,
 780             g_lookup_implementation_function_name, error));
 781         if (error.Fail()) {
 782           if (log)
 783             log->Printf(
 784                 "Failed to get Utility Function for implementation lookup: %s.",
 785                 error.AsCString());
 786           m_impl_code.reset();
 787           return args_addr;
 788         }
 789
 790         if (!m_impl_code->Install(diagnostics, exe_ctx)) {
 791           if (log) {
 792             log->Printf("Failed to install implementation lookup.");
 793             diagnostics.Dump(log);
 794           }
 795           m_impl_code.reset();
 796           return args_addr;
 797         }
 798       } else {
 799         if (log)
 800           log->Printf("No method lookup implementation code.");
 801         return LLDB_INVALID_ADDRESS;
 802       }
 803
 804       // Next make the runner function for our implementation utility function.
 805       ClangASTContext *clang_ast_context =
 806           thread.GetProcess()->GetTarget().GetScratchClangASTContext();
 807       CompilerType clang_void_ptr_type =
 808           clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
 809       Status error;
 810
 811       impl_function_caller = m_impl_code->MakeFunctionCaller(
 812           clang_void_ptr_type, dispatch_values, thread_sp, error);
 813       if (error.Fail()) {
 814         if (log)
 815           log->Printf(
 816               "Error getting function caller for dispatch lookup: \"%s\".",
 817               error.AsCString());
 818         return args_addr;
 819       }
 820     } else {
 821       impl_function_caller = m_impl_code->GetFunctionCaller();
 822     }
 823   }
 824
 825   diagnostics.Clear();
 826
 827   // Now write down the argument values for this particular call.
 828   // This looks like it might be a race condition if other threads
 829   // were calling into here, but actually it isn't because we allocate
 830   // a new args structure for this call by passing args_addr =
 831   // LLDB_INVALID_ADDRESS...
 832
 833   if (!impl_function_caller->WriteFunctionArguments(
 834           exe_ctx, args_addr, dispatch_values, diagnostics)) {
 835     if (log) {
 836       log->Printf("Error writing function arguments.");
 837       diagnostics.Dump(log);
 838     }
 839     return args_addr;
 840   }
 841
 842   return args_addr;
 843 }
 844
 845 ThreadPlanSP
 846 AppleObjCTrampolineHandler::GetStepThroughDispatchPlan(Thread &thread,
 847                                                        bool stop_others) {
 848   ThreadPlanSP ret_plan_sp;
 849   lldb::addr_t curr_pc = thread.GetRegisterContext()->GetPC();
 850
 851   DispatchFunction this_dispatch;
 852   bool found_it = false;
 853
 854   // First step is to look and see if we are in one of the known ObjC
 855   // dispatch functions.  We've already compiled a table of same, so
 856   // consult it.
 857
 858   MsgsendMap::iterator pos;
 859   pos = m_msgSend_map.find(curr_pc);
 860   if (pos != m_msgSend_map.end()) {
 861     this_dispatch = g_dispatch_functions[(*pos).second];
 862     found_it = true;
 863   }
 864
 865   // Next check to see if we are in a vtable region:
 866
 867   if (!found_it) {
 868     uint32_t flags;
 869     if (m_vtables_up) {
 870       found_it = m_vtables_up->IsAddressInVTables(curr_pc, flags);
 871       if (found_it) {
 872         this_dispatch.name = "vtable";
 873         this_dispatch.stret_return =
 874             (flags & AppleObjCVTables::eOBJC_TRAMPOLINE_STRET) ==
 875             AppleObjCVTables::eOBJC_TRAMPOLINE_STRET;
 876         this_dispatch.is_super = false;
 877         this_dispatch.is_super2 = false;
 878         this_dispatch.fixedup = DispatchFunction::eFixUpFixed;
 879       }
 880     }
 881   }
 882
 883   if (found_it) {
 884     Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
 885
 886     // We are decoding a method dispatch.  First job is to pull the
 887     // arguments out:
 888
 889     lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
 890
 891     const ABI *abi = nullptr;
 892     ProcessSP process_sp(thread.CalculateProcess());
 893     if (process_sp)
 894       abi = process_sp->GetABI().get();
 895     if (abi == nullptr)
 896       return ret_plan_sp;
 897
 898     TargetSP target_sp(thread.CalculateTarget());
 899
 900     ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext();
 901     ValueList argument_values;
 902     Value void_ptr_value;
 903     CompilerType clang_void_ptr_type =
 904         clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
 905     void_ptr_value.SetValueType(Value::eValueTypeScalar);
 906     // void_ptr_value.SetContext (Value::eContextTypeClangType,
 907     // clang_void_ptr_type);
 908     void_ptr_value.SetCompilerType(clang_void_ptr_type);
 909
 910     int obj_index;
 911     int sel_index;
 912
 913     // If this is a struct return dispatch, then the first argument is
 914     // the return struct pointer, and the object is the second, and
 915     // the selector is the third.  Otherwise the object is the first
 916     // and the selector the second.
 917     if (this_dispatch.stret_return) {
 918       obj_index = 1;
 919       sel_index = 2;
 920       argument_values.PushValue(void_ptr_value);
 921       argument_values.PushValue(void_ptr_value);
 922       argument_values.PushValue(void_ptr_value);
 923     } else {
 924       obj_index = 0;
 925       sel_index = 1;
 926       argument_values.PushValue(void_ptr_value);
 927       argument_values.PushValue(void_ptr_value);
 928     }
 929
 930     bool success = abi->GetArgumentValues(thread, argument_values);
 931     if (!success)
 932       return ret_plan_sp;
 933
 934     lldb::addr_t obj_addr =
 935         argument_values.GetValueAtIndex(obj_index)->GetScalar().ULongLong();
 936     if (obj_addr == 0x0) {
 937       if (log)
 938         log->Printf(
 939             "Asked to step to dispatch to nil object, returning empty plan.");
 940       return ret_plan_sp;
 941     }
 942
 943     ExecutionContext exe_ctx(thread.shared_from_this());
 944     Process *process = exe_ctx.GetProcessPtr();
 945     // isa_addr will store the class pointer that the method is being
 946     // dispatched to - so either the class directly or the super class
 947     // if this is one of the objc_msgSendSuper flavors.  That's mostly
 948     // used to look up the class/selector pair in our cache.
 949
 950     lldb::addr_t isa_addr = LLDB_INVALID_ADDRESS;
 951     lldb::addr_t sel_addr =
 952         argument_values.GetValueAtIndex(sel_index)->GetScalar().ULongLong();
 953
 954     // Figure out the class this is being dispatched to and see if
 955     // we've already cached this method call, If so we can push a
 956     // run-to-address plan directly.  Otherwise we have to figure out
 957     // where the implementation lives.
 958
 959     if (this_dispatch.is_super) {
 960       if (this_dispatch.is_super2) {
 961         // In the objc_msgSendSuper2 case, we don't get the object
 962         // directly, we get a structure containing the object and the
 963         // class to which the super message is being sent.  So we need
 964         // to dig the super out of the class and use that.
 965
 966         Value super_value(*(argument_values.GetValueAtIndex(obj_index)));
 967         super_value.GetScalar() += process->GetAddressByteSize();
 968         super_value.ResolveValue(&exe_ctx);
 969
 970         if (super_value.GetScalar().IsValid()) {
 971
 972           // isa_value now holds the class pointer.  The second word of the
 973           // class pointer is the super-class pointer:
 974           super_value.GetScalar() += process->GetAddressByteSize();
 975           super_value.ResolveValue(&exe_ctx);
 976           if (super_value.GetScalar().IsValid())
 977             isa_addr = super_value.GetScalar().ULongLong();
 978           else {
 979             if (log)
 980               log->Printf("Failed to extract the super class value from the "
 981                           "class in objc_super.");
 982           }
 983         } else {
 984           if (log)
 985             log->Printf("Failed to extract the class value from objc_super.");
 986         }
 987       } else {
 988         // In the objc_msgSendSuper case, we don't get the object
 989         // directly, we get a two element structure containing the
 990         // object and the super class to which the super message is
 991         // being sent.  So the class we want is the second element of
 992         // this structure.
 993
 994         Value super_value(*(argument_values.GetValueAtIndex(obj_index)));
 995         super_value.GetScalar() += process->GetAddressByteSize();
 996         super_value.ResolveValue(&exe_ctx);
 997
 998         if (super_value.GetScalar().IsValid()) {
 999           isa_addr = super_value.GetScalar().ULongLong();
1000         } else {
1001           if (log)
1002             log->Printf("Failed to extract the class value from objc_super.");
1003         }
1004       }
1005     } else {
1006       // In the direct dispatch case, the object->isa is the class pointer we
1007       // want.
1008
1009       // This is a little cheesy, but since object->isa is the first field,
1010       // making the object value a load address value and resolving it will get
1011       // the pointer sized data pointed to by that value...
1012
1013       // Note, it isn't a fatal error not to be able to get the
1014       // address from the object, since this might be a "tagged
1015       // pointer" which isn't a real object, but rather some word
1016       // length encoded dingus.
1017
1018       Value isa_value(*(argument_values.GetValueAtIndex(obj_index)));
1019
1020       isa_value.SetValueType(Value::eValueTypeLoadAddress);
1021       isa_value.ResolveValue(&exe_ctx);
1022       if (isa_value.GetScalar().IsValid()) {
1023         isa_addr = isa_value.GetScalar().ULongLong();
1024       } else {
1025         if (log)
1026           log->Printf("Failed to extract the isa value from object.");
1027       }
1028     }
1029
1030     // Okay, we've got the address of the class for which we're resolving this,
1031     // let's see if it's in our cache:
1032     lldb::addr_t impl_addr = LLDB_INVALID_ADDRESS;
1033
1034     if (isa_addr != LLDB_INVALID_ADDRESS) {
1035       if (log) {
1036         log->Printf("Resolving call for class - 0x%" PRIx64
1037                     " and selector - 0x%" PRIx64,
1038                     isa_addr, sel_addr);
1039       }
1040       ObjCLanguageRuntime *objc_runtime =
1041           ObjCLanguageRuntime::Get(*thread.GetProcess());
1042       assert(objc_runtime != nullptr);
1043
1044       impl_addr = objc_runtime->LookupInMethodCache(isa_addr, sel_addr);
1045     }
1046
1047     if (impl_addr != LLDB_INVALID_ADDRESS) {
1048       // Yup, it was in the cache, so we can run to that address directly.
1049
1050       if (log)
1051         log->Printf("Found implementation address in cache: 0x%" PRIx64,
1052                     impl_addr);
1053
1054       ret_plan_sp = std::make_shared<ThreadPlanRunToAddress>(thread, impl_addr,
1055                                                              stop_others);
1056     } else {
1057       // We haven't seen this class/selector pair yet.  Look it up.
1058       StreamString errors;
1059       Address impl_code_address;
1060
1061       ValueList dispatch_values;
1062
1063       // We've will inject a little function in the target that takes the
1064       // object, selector and some flags,
1065       // and figures out the implementation.  Looks like:
1066       //      void *__lldb_objc_find_implementation_for_selector (void *object,
1067       //                                                          void *sel,
1068       //                                                          int is_stret,
1069       //                                                          int is_super,
1070       //                                                          int is_super2,
1071       //                                                          int is_fixup,
1072       //                                                          int is_fixed,
1073       //                                                          int debug)
1074       // So set up the arguments for that call.
1075
1076       dispatch_values.PushValue(*(argument_values.GetValueAtIndex(obj_index)));
1077       dispatch_values.PushValue(*(argument_values.GetValueAtIndex(sel_index)));
1078
1079       Value flag_value;
1080       CompilerType clang_int_type =
1081           clang_ast_context->GetBuiltinTypeForEncodingAndBitSize(
1082               lldb::eEncodingSint, 32);
1083       flag_value.SetValueType(Value::eValueTypeScalar);
1084       // flag_value.SetContext (Value::eContextTypeClangType, clang_int_type);
1085       flag_value.SetCompilerType(clang_int_type);
1086
1087       if (this_dispatch.stret_return)
1088         flag_value.GetScalar() = 1;
1089       else
1090         flag_value.GetScalar() = 0;
1091       dispatch_values.PushValue(flag_value);
1092
1093       if (this_dispatch.is_super)
1094         flag_value.GetScalar() = 1;
1095       else
1096         flag_value.GetScalar() = 0;
1097       dispatch_values.PushValue(flag_value);
1098
1099       if (this_dispatch.is_super2)
1100         flag_value.GetScalar() = 1;
1101       else
1102         flag_value.GetScalar() = 0;
1103       dispatch_values.PushValue(flag_value);
1104
1105       switch (this_dispatch.fixedup) {
1106       case DispatchFunction::eFixUpNone:
1107         flag_value.GetScalar() = 0;
1108         dispatch_values.PushValue(flag_value);
1109         dispatch_values.PushValue(flag_value);
1110         break;
1111       case DispatchFunction::eFixUpFixed:
1112         flag_value.GetScalar() = 1;
1113         dispatch_values.PushValue(flag_value);
1114         flag_value.GetScalar() = 1;
1115         dispatch_values.PushValue(flag_value);
1116         break;
1117       case DispatchFunction::eFixUpToFix:
1118         flag_value.GetScalar() = 1;
1119         dispatch_values.PushValue(flag_value);
1120         flag_value.GetScalar() = 0;
1121         dispatch_values.PushValue(flag_value);
1122         break;
1123       }
1124       if (log && log->GetVerbose())
1125         flag_value.GetScalar() = 1;
1126       else
1127         flag_value.GetScalar() = 0; // FIXME - Set to 0 when debugging is done.
1128       dispatch_values.PushValue(flag_value);
1129
1130       // The step through code might have to fill in the cache, so it
1131       // is not safe to run only one thread.  So we override the
1132       // stop_others value passed in to us here:
1133       const bool trampoline_stop_others = false;
1134       ret_plan_sp = std::make_shared<AppleThreadPlanStepThroughObjCTrampoline>(
1135           thread, this, dispatch_values, isa_addr, sel_addr,
1136           trampoline_stop_others);
1137       if (log) {
1138         StreamString s;
1139         ret_plan_sp->GetDescription(&s, eDescriptionLevelFull);
1140         log->Printf("Using ObjC step plan: %s.\n", s.GetData());
1141       }
1142     }
1143   }
1144
1145   return ret_plan_sp;
1146 }
1147
1148 FunctionCaller *
1149 AppleObjCTrampolineHandler::GetLookupImplementationFunctionCaller() {
1150   return m_impl_code->GetFunctionCaller();
1151 }