source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTrampolineHandler.cpp

   1 //===-- AppleObjCTrampolineHandler.cpp ----------------------------*- C++
   2 //-*-===//
   3 //
   4 //                     The LLVM Compiler Infrastructure
   5 //
   6 // This file is distributed under the University of Illinois Open Source
   7 // License. See LICENSE.TXT for details.
   8 //
   9 //===----------------------------------------------------------------------===//
  10
  11 #include "AppleObjCTrampolineHandler.h"
  12
  13 // C Includes
  14 // C++ Includes
  15 // Other libraries and framework includes
  16 // Project includes
  17 #include "AppleThreadPlanStepThroughObjCTrampoline.h"
  18
  19 #include "lldb/Breakpoint/StoppointCallbackContext.h"
  20 #include "lldb/Core/Debugger.h"
  21 #include "lldb/Core/Module.h"
  22 #include "lldb/Core/StreamFile.h"
  23 #include "lldb/Core/Value.h"
  24 #include "lldb/Expression/DiagnosticManager.h"
  25 #include "lldb/Expression/FunctionCaller.h"
  26 #include "lldb/Expression/UserExpression.h"
  27 #include "lldb/Expression/UtilityFunction.h"
  28 #include "lldb/Symbol/ClangASTContext.h"
  29 #include "lldb/Symbol/Symbol.h"
  30 #include "lldb/Target/ABI.h"
  31 #include "lldb/Target/ExecutionContext.h"
  32 #include "lldb/Target/ObjCLanguageRuntime.h"
  33 #include "lldb/Target/Process.h"
  34 #include "lldb/Target/RegisterContext.h"
  35 #include "lldb/Target/Target.h"
  36 #include "lldb/Target/Thread.h"
  37 #include "lldb/Target/ThreadPlanRunToAddress.h"
  38 #include "lldb/Utility/ConstString.h"
  39 #include "lldb/Utility/FileSpec.h"
  40 #include "lldb/Utility/Log.h"
  41
  42 #include "llvm/ADT/STLExtras.h"
  43
  44 using namespace lldb;
  45 using namespace lldb_private;
  46
  47 const char *AppleObjCTrampolineHandler::g_lookup_implementation_function_name =
  48     "__lldb_objc_find_implementation_for_selector";
  49 const char *AppleObjCTrampolineHandler::
  50     g_lookup_implementation_with_stret_function_code =
  51         "                               \n\
  52 extern \"C\"                                                                 \n\
  53 {                                                                            \n\
  54     extern void *class_getMethodImplementation(void *objc_class, void *sel); \n\
  55     extern void *class_getMethodImplementation_stret(void *objc_class,       \n\
  56                                                      void *sel);             \n\
  57     extern void * object_getClass (id object);                               \n\
  58     extern void * sel_getUid(char *name);                                    \n\
  59     extern int printf(const char *format, ...);                              \n\
  60 }                                                                            \n\
  61 extern \"C\" void * __lldb_objc_find_implementation_for_selector (           \n\
  62                                                     void *object,            \n\
  63                                                     void *sel,               \n\
  64                                                     int is_stret,            \n\
  65                                                     int is_super,            \n\
  66                                                     int is_super2,           \n\
  67                                                     int is_fixup,            \n\
  68                                                     int is_fixed,            \n\
  69                                                     int debug)               \n\
  70 {                                                                            \n\
  71     struct __lldb_imp_return_struct                                          \n\
  72     {                                                                        \n\
  73         void *class_addr;                                                    \n\
  74         void *sel_addr;                                                      \n\
  75         void *impl_addr;                                                     \n\
  76     };                                                                       \n\
  77                                                                              \n\
  78     struct __lldb_objc_class {                                               \n\
  79         void *isa;                                                           \n\
  80         void *super_ptr;                                                     \n\
  81     };                                                                       \n\
  82     struct __lldb_objc_super {                                               \n\
  83         void *reciever;                                                      \n\
  84         struct __lldb_objc_class *class_ptr;                                 \n\
  85     };                                                                       \n\
  86     struct __lldb_msg_ref {                                                  \n\
  87         void *dont_know;                                                     \n\
  88         void *sel;                                                           \n\
  89     };                                                                       \n\
  90                                                                              \n\
  91     struct __lldb_imp_return_struct return_struct;                           \n\
  92                                                                              \n\
  93     if (debug)                                                               \n\
  94         printf (\"\\n*** Called with obj: 0x%p sel: 0x%p is_stret: %d is_super: %d, \"\n\
  95                 \"is_super2: %d, is_fixup: %d, is_fixed: %d\\n\",            \n\
  96                  object, sel, is_stret, is_super, is_super2, is_fixup, is_fixed);\n\
  97     if (is_super)                                                            \n\
  98     {                                                                        \n\
  99         if (is_super2)                                                       \n\
 100         {                                                                    \n\
 101             return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr->super_ptr;\n\
 102         }                                                                    \n\
 103         else                                                                 \n\
 104         {                                                                    \n\
 105             return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr;\n\
 106         }                                                                    \n\
 107     }                                                                        \n\
 108     else                                                                     \n\
 109     {                                                                        \n\
 110         // This code seems a little funny, but has its reasons...            \n\
 111                                                                              \n\
 112         // The call to [object class] is here because if this is a           \n\
 113         // class, and has not been called into yet, we need to do            \n\
 114         // something to force the class to initialize itself.                \n\
 115         // Then the call to object_getClass will actually return the         \n\
 116         // correct class, either the class if object is a class              \n\
 117         // instance, or the meta-class if it is a class pointer.             \n\
 118         void *class_ptr = (void *) [(id) object class];                      \n\
 119         return_struct.class_addr = (id)  object_getClass((id) object);       \n\
 120         if (debug)                                                           \n\
 121         {                                                                    \n\
 122             if (class_ptr == object)                                         \n\
 123             {                                                                \n\
 124                 printf (\"Found a class object, need to use the meta class %p -> %p\\n\",\n\
 125                         class_ptr, return_struct.class_addr);                \n\
 126             }                                                                \n\
 127             else                                                             \n\
 128             {                                                                \n\
 129                  printf (\"[object class] returned: %p object_getClass: %p.\\n\", \n\
 130                  class_ptr, return_struct.class_addr);                       \n\
 131             }                                                                \n\
 132         }                                                                    \n\
 133     }                                                                        \n\
 134                                                                              \n\
 135     if (is_fixup)                                                            \n\
 136     {                                                                        \n\
 137         if (is_fixed)                                                        \n\
 138         {                                                                    \n\
 139             return_struct.sel_addr = ((__lldb_msg_ref *) sel)->sel;          \n\
 140         }                                                                    \n\
 141         else                                                                 \n\
 142         {                                                                    \n\
 143             char *sel_name = (char *) ((__lldb_msg_ref *) sel)->sel;         \n\
 144             return_struct.sel_addr = sel_getUid (sel_name);                  \n\
 145             if (debug)                                                       \n\
 146                 printf (\"\\n*** Got fixed up selector: %p for name %s.\\n\",\n\
 147                         return_struct.sel_addr, sel_name);                   \n\
 148         }                                                                    \n\
 149     }                                                                        \n\
 150     else                                                                     \n\
 151     {                                                                        \n\
 152         return_struct.sel_addr = sel;                                        \n\
 153     }                                                                        \n\
 154                                                                              \n\
 155     if (is_stret)                                                            \n\
 156     {                                                                        \n\
 157         return_struct.impl_addr =                                            \n\
 158           class_getMethodImplementation_stret (return_struct.class_addr,     \n\
 159                                                return_struct.sel_addr);      \n\
 160     }                                                                        \n\
 161     else                                                                     \n\
 162     {                                                                        \n\
 163         return_struct.impl_addr =                                            \n\
 164             class_getMethodImplementation (return_struct.class_addr,         \n\
 165                                            return_struct.sel_addr);          \n\
 166     }                                                                        \n\
 167     if (debug)                                                               \n\
 168         printf (\"\\n*** Returning implementation: %p.\\n\",                 \n\
 169                           return_struct.impl_addr);                          \n\
 170                                                                              \n\
 171     return return_struct.impl_addr;                                          \n\
 172 }                                                                            \n\
 173 ";
 174 const char *
 175     AppleObjCTrampolineHandler::g_lookup_implementation_no_stret_function_code =
 176         "                      \n\
 177 extern \"C\"                                                                 \n\
 178 {                                                                            \n\
 179     extern void *class_getMethodImplementation(void *objc_class, void *sel); \n\
 180     extern void * object_getClass (id object);                               \n\
 181     extern void * sel_getUid(char *name);                                    \n\
 182     extern int printf(const char *format, ...);                              \n\
 183 }                                                                            \n\
 184 extern \"C\" void * __lldb_objc_find_implementation_for_selector (void *object,                                 \n\
 185                                                     void *sel,               \n\
 186                                                     int is_stret,            \n\
 187                                                     int is_super,            \n\
 188                                                     int is_super2,           \n\
 189                                                     int is_fixup,            \n\
 190                                                     int is_fixed,            \n\
 191                                                     int debug)               \n\
 192 {                                                                            \n\
 193     struct __lldb_imp_return_struct                                          \n\
 194     {                                                                        \n\
 195         void *class_addr;                                                    \n\
 196         void *sel_addr;                                                      \n\
 197         void *impl_addr;                                                     \n\
 198     };                                                                       \n\
 199                                                                              \n\
 200     struct __lldb_objc_class {                                               \n\
 201         void *isa;                                                           \n\
 202         void *super_ptr;                                                     \n\
 203     };                                                                       \n\
 204     struct __lldb_objc_super {                                               \n\
 205         void *reciever;                                                      \n\
 206         struct __lldb_objc_class *class_ptr;                                 \n\
 207     };                                                                       \n\
 208     struct __lldb_msg_ref {                                                  \n\
 209         void *dont_know;                                                     \n\
 210         void *sel;                                                           \n\
 211     };                                                                       \n\
 212                                                                              \n\
 213     struct __lldb_imp_return_struct return_struct;                           \n\
 214                                                                              \n\
 215     if (debug)                                                               \n\
 216         printf (\"\\n*** Called with obj: 0x%p sel: 0x%p is_stret: %d is_super: %d, \"                          \n\
 217                 \"is_super2: %d, is_fixup: %d, is_fixed: %d\\n\",            \n\
 218                  object, sel, is_stret, is_super, is_super2, is_fixup, is_fixed);                               \n\
 219     if (is_super)                                                            \n\
 220     {                                                                        \n\
 221         if (is_super2)                                                       \n\
 222         {                                                                    \n\
 223             return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr->super_ptr;                    \n\
 224         }                                                                    \n\
 225         else                                                                 \n\
 226         {                                                                    \n\
 227             return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr;                               \n\
 228         }                                                                    \n\
 229     }                                                                        \n\
 230     else                                                                     \n\
 231     {                                                                        \n\
 232         // This code seems a little funny, but has its reasons...            \n\
 233         // The call to [object class] is here because if this is a class, and has not been called into          \n\
 234         // yet, we need to do something to force the class to initialize itself.                                \n\
 235         // Then the call to object_getClass will actually return the correct class, either the class            \n\
 236         // if object is a class instance, or the meta-class if it is a class pointer.                           \n\
 237         void *class_ptr = (void *) [(id) object class];                      \n\
 238         return_struct.class_addr = (id)  object_getClass((id) object);       \n\
 239         if (debug)                                                           \n\
 240         {                                                                    \n\
 241             if (class_ptr == object)                                         \n\
 242             {                                                                \n\
 243                 printf (\"Found a class object, need to return the meta class %p -> %p\\n\",                    \n\
 244                         class_ptr, return_struct.class_addr);                \n\
 245             }                                                                \n\
 246             else                                                             \n\
 247             {                                                                \n\
 248                  printf (\"[object class] returned: %p object_getClass: %p.\\n\",                               \n\
 249                  class_ptr, return_struct.class_addr);                       \n\
 250             }                                                                \n\
 251         }                                                                    \n\
 252     }                                                                        \n\
 253                                                                              \n\
 254     if (is_fixup)                                                            \n\
 255     {                                                                        \n\
 256         if (is_fixed)                                                        \n\
 257         {                                                                    \n\
 258             return_struct.sel_addr = ((__lldb_msg_ref *) sel)->sel;          \n\
 259         }                                                                    \n\
 260         else                                                                 \n\
 261         {                                                                    \n\
 262             char *sel_name = (char *) ((__lldb_msg_ref *) sel)->sel;         \n\
 263             return_struct.sel_addr = sel_getUid (sel_name);                  \n\
 264             if (debug)                                                       \n\
 265                 printf (\"\\n*** Got fixed up selector: %p for name %s.\\n\",\n\
 266                         return_struct.sel_addr, sel_name);                   \n\
 267         }                                                                    \n\
 268     }                                                                        \n\
 269     else                                                                     \n\
 270     {                                                                        \n\
 271         return_struct.sel_addr = sel;                                        \n\
 272     }                                                                        \n\
 273                                                                              \n\
 274     return_struct.impl_addr =                                                \n\
 275       class_getMethodImplementation (return_struct.class_addr,               \n\
 276                                      return_struct.sel_addr);                \n\
 277     if (debug)                                                               \n\
 278         printf (\"\\n*** Returning implementation: 0x%p.\\n\",               \n\
 279           return_struct.impl_addr);                                          \n\
 280                                                                              \n\
 281     return return_struct.impl_addr;                                          \n\
 282 }                                                                            \n\
 283 ";
 284
 285 AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::VTableRegion(
 286     AppleObjCVTables *owner, lldb::addr_t header_addr)
 287     : m_valid(true), m_owner(owner), m_header_addr(header_addr),
 288       m_code_start_addr(0), m_code_end_addr(0), m_next_region(0) {
 289   SetUpRegion();
 290 }
 291
 292 AppleObjCTrampolineHandler::~AppleObjCTrampolineHandler() {}
 293
 294 void AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::SetUpRegion() {
 295   // The header looks like:
 296   //
 297   //   uint16_t headerSize
 298   //   uint16_t descSize
 299   //   uint32_t descCount
 300   //   void * next
 301   //
 302   // First read in the header:
 303
 304   char memory_buffer[16];
 305   ProcessSP process_sp = m_owner->GetProcessSP();
 306   if (!process_sp)
 307     return;
 308   DataExtractor data(memory_buffer, sizeof(memory_buffer),
 309                      process_sp->GetByteOrder(),
 310                      process_sp->GetAddressByteSize());
 311   size_t actual_size = 8 + process_sp->GetAddressByteSize();
 312   Status error;
 313   size_t bytes_read =
 314       process_sp->ReadMemory(m_header_addr, memory_buffer, actual_size, error);
 315   if (bytes_read != actual_size) {
 316     m_valid = false;
 317     return;
 318   }
 319
 320   lldb::offset_t offset = 0;
 321   const uint16_t header_size = data.GetU16(&offset);
 322   const uint16_t descriptor_size = data.GetU16(&offset);
 323   const size_t num_descriptors = data.GetU32(&offset);
 324
 325   m_next_region = data.GetPointer(&offset);
 326
 327   // If the header size is 0, that means we've come in too early before this
 328   // data is set up.
 329   // Set ourselves as not valid, and continue.
 330   if (header_size == 0 || num_descriptors == 0) {
 331     m_valid = false;
 332     return;
 333   }
 334
 335   // Now read in all the descriptors:
 336   // The descriptor looks like:
 337   //
 338   // uint32_t offset
 339   // uint32_t flags
 340   //
 341   // Where offset is either 0 - in which case it is unused, or it is
 342   // the offset of the vtable code from the beginning of the
 343   // descriptor record.  Below, we'll convert that into an absolute
 344   // code address, since I don't want to have to compute it over and
 345   // over.
 346
 347   // Ingest the whole descriptor array:
 348   const lldb::addr_t desc_ptr = m_header_addr + header_size;
 349   const size_t desc_array_size = num_descriptors * descriptor_size;
 350   DataBufferSP data_sp(new DataBufferHeap(desc_array_size, '\0'));
 351   uint8_t *dst = (uint8_t *)data_sp->GetBytes();
 352
 353   DataExtractor desc_extractor(dst, desc_array_size, process_sp->GetByteOrder(),
 354                                process_sp->GetAddressByteSize());
 355   bytes_read = process_sp->ReadMemory(desc_ptr, dst, desc_array_size, error);
 356   if (bytes_read != desc_array_size) {
 357     m_valid = false;
 358     return;
 359   }
 360
 361   // The actual code for the vtables will be laid out consecutively, so I also
 362   // compute the start and end of the whole code block.
 363
 364   offset = 0;
 365   m_code_start_addr = 0;
 366   m_code_end_addr = 0;
 367
 368   for (size_t i = 0; i < num_descriptors; i++) {
 369     lldb::addr_t start_offset = offset;
 370     uint32_t voffset = desc_extractor.GetU32(&offset);
 371     uint32_t flags = desc_extractor.GetU32(&offset);
 372     lldb::addr_t code_addr = desc_ptr + start_offset + voffset;
 373     m_descriptors.push_back(VTableDescriptor(flags, code_addr));
 374
 375     if (m_code_start_addr == 0 || code_addr < m_code_start_addr)
 376       m_code_start_addr = code_addr;
 377     if (code_addr > m_code_end_addr)
 378       m_code_end_addr = code_addr;
 379
 380     offset = start_offset + descriptor_size;
 381   }
 382   // Finally, a little bird told me that all the vtable code blocks
 383   // are the same size.  Let's compute the blocks and if they are all
 384   // the same add the size to the code end address:
 385   lldb::addr_t code_size = 0;
 386   bool all_the_same = true;
 387   for (size_t i = 0; i < num_descriptors - 1; i++) {
 388     lldb::addr_t this_size =
 389         m_descriptors[i + 1].code_start - m_descriptors[i].code_start;
 390     if (code_size == 0)
 391       code_size = this_size;
 392     else {
 393       if (this_size != code_size)
 394         all_the_same = false;
 395       if (this_size > code_size)
 396         code_size = this_size;
 397     }
 398   }
 399   if (all_the_same)
 400     m_code_end_addr += code_size;
 401 }
 402
 403 bool AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::
 404     AddressInRegion(lldb::addr_t addr, uint32_t &flags) {
 405   if (!IsValid())
 406     return false;
 407
 408   if (addr < m_code_start_addr || addr > m_code_end_addr)
 409     return false;
 410
 411   std::vector<VTableDescriptor>::iterator pos, end = m_descriptors.end();
 412   for (pos = m_descriptors.begin(); pos != end; pos++) {
 413     if (addr <= (*pos).code_start) {
 414       flags = (*pos).flags;
 415       return true;
 416     }
 417   }
 418   return false;
 419 }
 420
 421 void AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::Dump(
 422     Stream &s) {
 423   s.Printf("Header addr: 0x%" PRIx64 " Code start: 0x%" PRIx64
 424            " Code End: 0x%" PRIx64 " Next: 0x%" PRIx64 "\n",
 425            m_header_addr, m_code_start_addr, m_code_end_addr, m_next_region);
 426   size_t num_elements = m_descriptors.size();
 427   for (size_t i = 0; i < num_elements; i++) {
 428     s.Indent();
 429     s.Printf("Code start: 0x%" PRIx64 " Flags: %d\n",
 430              m_descriptors[i].code_start, m_descriptors[i].flags);
 431   }
 432 }
 433
 434 AppleObjCTrampolineHandler::AppleObjCVTables::AppleObjCVTables(
 435     const ProcessSP &process_sp, const ModuleSP &objc_module_sp)
 436     : m_process_wp(), m_trampoline_header(LLDB_INVALID_ADDRESS),
 437       m_trampolines_changed_bp_id(LLDB_INVALID_BREAK_ID),
 438       m_objc_module_sp(objc_module_sp) {
 439   if (process_sp)
 440     m_process_wp = process_sp;
 441 }
 442
 443 AppleObjCTrampolineHandler::AppleObjCVTables::~AppleObjCVTables() {
 444   ProcessSP process_sp = GetProcessSP();
 445   if (process_sp) {
 446     if (m_trampolines_changed_bp_id != LLDB_INVALID_BREAK_ID)
 447       process_sp->GetTarget().RemoveBreakpointByID(m_trampolines_changed_bp_id);
 448   }
 449 }
 450
 451 bool AppleObjCTrampolineHandler::AppleObjCVTables::InitializeVTableSymbols() {
 452   if (m_trampoline_header != LLDB_INVALID_ADDRESS)
 453     return true;
 454
 455   ProcessSP process_sp = GetProcessSP();
 456   if (process_sp) {
 457     Target &target = process_sp->GetTarget();
 458
 459     const ModuleList &target_modules = target.GetImages();
 460     std::lock_guard<std::recursive_mutex> guard(target_modules.GetMutex());
 461     size_t num_modules = target_modules.GetSize();
 462     if (!m_objc_module_sp) {
 463       for (size_t i = 0; i < num_modules; i++) {
 464         if (process_sp->GetObjCLanguageRuntime()->IsModuleObjCLibrary(
 465                 target_modules.GetModuleAtIndexUnlocked(i))) {
 466           m_objc_module_sp = target_modules.GetModuleAtIndexUnlocked(i);
 467           break;
 468         }
 469       }
 470     }
 471
 472     if (m_objc_module_sp) {
 473       ConstString trampoline_name("gdb_objc_trampolines");
 474       const Symbol *trampoline_symbol =
 475           m_objc_module_sp->FindFirstSymbolWithNameAndType(trampoline_name,
 476                                                            eSymbolTypeData);
 477       if (trampoline_symbol != NULL) {
 478         m_trampoline_header = trampoline_symbol->GetLoadAddress(&target);
 479         if (m_trampoline_header == LLDB_INVALID_ADDRESS)
 480           return false;
 481
 482         // Next look up the "changed" symbol and set a breakpoint on that...
 483         ConstString changed_name("gdb_objc_trampolines_changed");
 484         const Symbol *changed_symbol =
 485             m_objc_module_sp->FindFirstSymbolWithNameAndType(changed_name,
 486                                                              eSymbolTypeCode);
 487         if (changed_symbol != NULL) {
 488           const Address changed_symbol_addr = changed_symbol->GetAddress();
 489           if (!changed_symbol_addr.IsValid())
 490             return false;
 491
 492           lldb::addr_t changed_addr =
 493               changed_symbol_addr.GetOpcodeLoadAddress(&target);
 494           if (changed_addr != LLDB_INVALID_ADDRESS) {
 495             BreakpointSP trampolines_changed_bp_sp =
 496                 target.CreateBreakpoint(changed_addr, true, false);
 497             if (trampolines_changed_bp_sp) {
 498               m_trampolines_changed_bp_id = trampolines_changed_bp_sp->GetID();
 499               trampolines_changed_bp_sp->SetCallback(RefreshTrampolines, this,
 500                                                      true);
 501               trampolines_changed_bp_sp->SetBreakpointKind(
 502                   "objc-trampolines-changed");
 503               return true;
 504             }
 505           }
 506         }
 507       }
 508     }
 509   }
 510   return false;
 511 }
 512
 513 bool AppleObjCTrampolineHandler::AppleObjCVTables::RefreshTrampolines(
 514     void *baton, StoppointCallbackContext *context, lldb::user_id_t break_id,
 515     lldb::user_id_t break_loc_id) {
 516   AppleObjCVTables *vtable_handler = (AppleObjCVTables *)baton;
 517   if (vtable_handler->InitializeVTableSymbols()) {
 518     // The Update function is called with the address of an added region.  So we
 519     // grab that address, and
 520     // feed it into ReadRegions.  Of course, our friend the ABI will get the
 521     // values for us.
 522     ExecutionContext exe_ctx(context->exe_ctx_ref);
 523     Process *process = exe_ctx.GetProcessPtr();
 524     const ABI *abi = process->GetABI().get();
 525
 526     ClangASTContext *clang_ast_context =
 527         process->GetTarget().GetScratchClangASTContext();
 528     ValueList argument_values;
 529     Value input_value;
 530     CompilerType clang_void_ptr_type =
 531         clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
 532
 533     input_value.SetValueType(Value::eValueTypeScalar);
 534     // input_value.SetContext (Value::eContextTypeClangType,
 535     // clang_void_ptr_type);
 536     input_value.SetCompilerType(clang_void_ptr_type);
 537     argument_values.PushValue(input_value);
 538
 539     bool success =
 540         abi->GetArgumentValues(exe_ctx.GetThreadRef(), argument_values);
 541     if (!success)
 542       return false;
 543
 544     // Now get a pointer value from the zeroth argument.
 545     Status error;
 546     DataExtractor data;
 547     error = argument_values.GetValueAtIndex(0)->GetValueAsData(&exe_ctx, data,
 548                                                                0, NULL);
 549     lldb::offset_t offset = 0;
 550     lldb::addr_t region_addr = data.GetPointer(&offset);
 551
 552     if (region_addr != 0)
 553       vtable_handler->ReadRegions(region_addr);
 554   }
 555   return false;
 556 }
 557
 558 bool AppleObjCTrampolineHandler::AppleObjCVTables::ReadRegions() {
 559   // The no argument version reads the  start region from the value of
 560   // the gdb_regions_header, and gets started from there.
 561
 562   m_regions.clear();
 563   if (!InitializeVTableSymbols())
 564     return false;
 565   Status error;
 566   ProcessSP process_sp = GetProcessSP();
 567   if (process_sp) {
 568     lldb::addr_t region_addr =
 569         process_sp->ReadPointerFromMemory(m_trampoline_header, error);
 570     if (error.Success())
 571       return ReadRegions(region_addr);
 572   }
 573   return false;
 574 }
 575
 576 bool AppleObjCTrampolineHandler::AppleObjCVTables::ReadRegions(
 577     lldb::addr_t region_addr) {
 578   ProcessSP process_sp = GetProcessSP();
 579   if (!process_sp)
 580     return false;
 581
 582   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
 583
 584   // We aren't starting at the trampoline symbol.
 585   InitializeVTableSymbols();
 586   lldb::addr_t next_region = region_addr;
 587
 588   // Read in the sizes of the headers.
 589   while (next_region != 0) {
 590     m_regions.push_back(VTableRegion(this, next_region));
 591     if (!m_regions.back().IsValid()) {
 592       m_regions.clear();
 593       return false;
 594     }
 595     if (log) {
 596       StreamString s;
 597       m_regions.back().Dump(s);
 598       log->Printf("Read vtable region: \n%s", s.GetData());
 599     }
 600
 601     next_region = m_regions.back().GetNextRegionAddr();
 602   }
 603
 604   return true;
 605 }
 606
 607 bool AppleObjCTrampolineHandler::AppleObjCVTables::IsAddressInVTables(
 608     lldb::addr_t addr, uint32_t &flags) {
 609   region_collection::iterator pos, end = m_regions.end();
 610   for (pos = m_regions.begin(); pos != end; pos++) {
 611     if ((*pos).AddressInRegion(addr, flags))
 612       return true;
 613   }
 614   return false;
 615 }
 616
 617 const AppleObjCTrampolineHandler::DispatchFunction
 618     AppleObjCTrampolineHandler::g_dispatch_functions[] = {
 619         // NAME                              STRET  SUPER  SUPER2  FIXUP TYPE
 620         {"objc_msgSend", false, false, false, DispatchFunction::eFixUpNone},
 621         {"objc_msgSend_fixup", false, false, false,
 622          DispatchFunction::eFixUpToFix},
 623         {"objc_msgSend_fixedup", false, false, false,
 624          DispatchFunction::eFixUpFixed},
 625         {"objc_msgSend_stret", true, false, false,
 626          DispatchFunction::eFixUpNone},
 627         {"objc_msgSend_stret_fixup", true, false, false,
 628          DispatchFunction::eFixUpToFix},
 629         {"objc_msgSend_stret_fixedup", true, false, false,
 630          DispatchFunction::eFixUpFixed},
 631         {"objc_msgSend_fpret", false, false, false,
 632          DispatchFunction::eFixUpNone},
 633         {"objc_msgSend_fpret_fixup", false, false, false,
 634          DispatchFunction::eFixUpToFix},
 635         {"objc_msgSend_fpret_fixedup", false, false, false,
 636          DispatchFunction::eFixUpFixed},
 637         {"objc_msgSend_fp2ret", false, false, true,
 638          DispatchFunction::eFixUpNone},
 639         {"objc_msgSend_fp2ret_fixup", false, false, true,
 640          DispatchFunction::eFixUpToFix},
 641         {"objc_msgSend_fp2ret_fixedup", false, false, true,
 642          DispatchFunction::eFixUpFixed},
 643         {"objc_msgSendSuper", false, true, false, DispatchFunction::eFixUpNone},
 644         {"objc_msgSendSuper_stret", true, true, false,
 645          DispatchFunction::eFixUpNone},
 646         {"objc_msgSendSuper2", false, true, true, DispatchFunction::eFixUpNone},
 647         {"objc_msgSendSuper2_fixup", false, true, true,
 648          DispatchFunction::eFixUpToFix},
 649         {"objc_msgSendSuper2_fixedup", false, true, true,
 650          DispatchFunction::eFixUpFixed},
 651         {"objc_msgSendSuper2_stret", true, true, true,
 652          DispatchFunction::eFixUpNone},
 653         {"objc_msgSendSuper2_stret_fixup", true, true, true,
 654          DispatchFunction::eFixUpToFix},
 655         {"objc_msgSendSuper2_stret_fixedup", true, true, true,
 656          DispatchFunction::eFixUpFixed},
 657 };
 658
 659 AppleObjCTrampolineHandler::AppleObjCTrampolineHandler(
 660     const ProcessSP &process_sp, const ModuleSP &objc_module_sp)
 661     : m_process_wp(), m_objc_module_sp(objc_module_sp),
 662       m_lookup_implementation_function_code(nullptr),
 663       m_impl_fn_addr(LLDB_INVALID_ADDRESS),
 664       m_impl_stret_fn_addr(LLDB_INVALID_ADDRESS),
 665       m_msg_forward_addr(LLDB_INVALID_ADDRESS) {
 666   if (process_sp)
 667     m_process_wp = process_sp;
 668   // Look up the known resolution functions:
 669
 670   ConstString get_impl_name("class_getMethodImplementation");
 671   ConstString get_impl_stret_name("class_getMethodImplementation_stret");
 672   ConstString msg_forward_name("_objc_msgForward");
 673   ConstString msg_forward_stret_name("_objc_msgForward_stret");
 674
 675   Target *target = process_sp ? &process_sp->GetTarget() : NULL;
 676   const Symbol *class_getMethodImplementation =
 677       m_objc_module_sp->FindFirstSymbolWithNameAndType(get_impl_name,
 678                                                        eSymbolTypeCode);
 679   const Symbol *class_getMethodImplementation_stret =
 680       m_objc_module_sp->FindFirstSymbolWithNameAndType(get_impl_stret_name,
 681                                                        eSymbolTypeCode);
 682   const Symbol *msg_forward = m_objc_module_sp->FindFirstSymbolWithNameAndType(
 683       msg_forward_name, eSymbolTypeCode);
 684   const Symbol *msg_forward_stret =
 685       m_objc_module_sp->FindFirstSymbolWithNameAndType(msg_forward_stret_name,
 686                                                        eSymbolTypeCode);
 687
 688   if (class_getMethodImplementation)
 689     m_impl_fn_addr =
 690         class_getMethodImplementation->GetAddress().GetOpcodeLoadAddress(
 691             target);
 692   if (class_getMethodImplementation_stret)
 693     m_impl_stret_fn_addr =
 694         class_getMethodImplementation_stret->GetAddress().GetOpcodeLoadAddress(
 695             target);
 696   if (msg_forward)
 697     m_msg_forward_addr = msg_forward->GetAddress().GetOpcodeLoadAddress(target);
 698   if (msg_forward_stret)
 699     m_msg_forward_stret_addr =
 700         msg_forward_stret->GetAddress().GetOpcodeLoadAddress(target);
 701
 702   // FIXME: Do some kind of logging here.
 703   if (m_impl_fn_addr == LLDB_INVALID_ADDRESS) {
 704     // If we can't even find the ordinary get method implementation function,
 705     // then we aren't going to be able to
 706     // step through any method dispatches.  Warn to that effect and get out of
 707     // here.
 708     if (process_sp->CanJIT()) {
 709       process_sp->GetTarget().GetDebugger().GetErrorFile()->Printf(
 710           "Could not find implementation lookup function \"%s\""
 711           " step in through ObjC method dispatch will not work.\n",
 712           get_impl_name.AsCString());
 713     }
 714     return;
 715   } else if (m_impl_stret_fn_addr == LLDB_INVALID_ADDRESS) {
 716     // It there is no stret return lookup function, assume that it is the same
 717     // as the straight lookup:
 718     m_impl_stret_fn_addr = m_impl_fn_addr;
 719     // Also we will use the version of the lookup code that doesn't rely on the
 720     // stret version of the function.
 721     m_lookup_implementation_function_code =
 722         g_lookup_implementation_no_stret_function_code;
 723   } else {
 724     m_lookup_implementation_function_code =
 725         g_lookup_implementation_with_stret_function_code;
 726   }
 727
 728   // Look up the addresses for the objc dispatch functions and cache
 729   // them.  For now I'm inspecting the symbol names dynamically to
 730   // figure out how to dispatch to them.  If it becomes more
 731   // complicated than this we can turn the g_dispatch_functions char *
 732   // array into a template table, and populate the DispatchFunction
 733   // map from there.
 734
 735   for (size_t i = 0; i != llvm::array_lengthof(g_dispatch_functions); i++) {
 736     ConstString name_const_str(g_dispatch_functions[i].name);
 737     const Symbol *msgSend_symbol =
 738         m_objc_module_sp->FindFirstSymbolWithNameAndType(name_const_str,
 739                                                          eSymbolTypeCode);
 740     if (msgSend_symbol && msgSend_symbol->ValueIsAddress()) {
 741       // FIXME: Make g_dispatch_functions static table of
 742       // DispatchFunctions, and have the map be address->index.
 743       // Problem is we also need to lookup the dispatch function.  For
 744       // now we could have a side table of stret & non-stret dispatch
 745       // functions.  If that's as complex as it gets, we're fine.
 746
 747       lldb::addr_t sym_addr =
 748           msgSend_symbol->GetAddressRef().GetOpcodeLoadAddress(target);
 749
 750       m_msgSend_map.insert(std::pair<lldb::addr_t, int>(sym_addr, i));
 751     }
 752   }
 753
 754   // Build our vtable dispatch handler here:
 755   m_vtables_ap.reset(new AppleObjCVTables(process_sp, m_objc_module_sp));
 756   if (m_vtables_ap.get())
 757     m_vtables_ap->ReadRegions();
 758 }
 759
 760 lldb::addr_t
 761 AppleObjCTrampolineHandler::SetupDispatchFunction(Thread &thread,
 762                                                   ValueList &dispatch_values) {
 763   ThreadSP thread_sp(thread.shared_from_this());
 764   ExecutionContext exe_ctx(thread_sp);
 765   DiagnosticManager diagnostics;
 766   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
 767
 768   lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
 769   FunctionCaller *impl_function_caller = nullptr;
 770
 771   // Scope for mutex locker:
 772   {
 773     std::lock_guard<std::mutex> guard(m_impl_function_mutex);
 774
 775     // First stage is to make the ClangUtility to hold our injected function:
 776
 777     if (!m_impl_code.get()) {
 778       if (m_lookup_implementation_function_code != NULL) {
 779         Status error;
 780         m_impl_code.reset(exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage(
 781             m_lookup_implementation_function_code, eLanguageTypeObjC,
 782             g_lookup_implementation_function_name, error));
 783         if (error.Fail()) {
 784           if (log)
 785             log->Printf(
 786                 "Failed to get Utility Function for implementation lookup: %s.",
 787                 error.AsCString());
 788           m_impl_code.reset();
 789           return args_addr;
 790         }
 791
 792         if (!m_impl_code->Install(diagnostics, exe_ctx)) {
 793           if (log) {
 794             log->Printf("Failed to install implementation lookup.");
 795             diagnostics.Dump(log);
 796           }
 797           m_impl_code.reset();
 798           return args_addr;
 799         }
 800       } else {
 801         if (log)
 802           log->Printf("No method lookup implementation code.");
 803         return LLDB_INVALID_ADDRESS;
 804       }
 805
 806       // Next make the runner function for our implementation utility function.
 807       ClangASTContext *clang_ast_context =
 808           thread.GetProcess()->GetTarget().GetScratchClangASTContext();
 809       CompilerType clang_void_ptr_type =
 810           clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
 811       Status error;
 812
 813       impl_function_caller = m_impl_code->MakeFunctionCaller(
 814           clang_void_ptr_type, dispatch_values, thread_sp, error);
 815       if (error.Fail()) {
 816         if (log)
 817           log->Printf(
 818               "Error getting function caller for dispatch lookup: \"%s\".",
 819               error.AsCString());
 820         return args_addr;
 821       }
 822     } else {
 823       impl_function_caller = m_impl_code->GetFunctionCaller();
 824     }
 825   }
 826
 827   diagnostics.Clear();
 828
 829   // Now write down the argument values for this particular call.
 830   // This looks like it might be a race condition if other threads
 831   // were calling into here, but actually it isn't because we allocate
 832   // a new args structure for this call by passing args_addr =
 833   // LLDB_INVALID_ADDRESS...
 834
 835   if (!impl_function_caller->WriteFunctionArguments(
 836           exe_ctx, args_addr, dispatch_values, diagnostics)) {
 837     if (log) {
 838       log->Printf("Error writing function arguments.");
 839       diagnostics.Dump(log);
 840     }
 841     return args_addr;
 842   }
 843
 844   return args_addr;
 845 }
 846
 847 ThreadPlanSP
 848 AppleObjCTrampolineHandler::GetStepThroughDispatchPlan(Thread &thread,
 849                                                        bool stop_others) {
 850   ThreadPlanSP ret_plan_sp;
 851   lldb::addr_t curr_pc = thread.GetRegisterContext()->GetPC();
 852
 853   DispatchFunction this_dispatch;
 854   bool found_it = false;
 855
 856   // First step is to look and see if we are in one of the known ObjC
 857   // dispatch functions.  We've already compiled a table of same, so
 858   // consult it.
 859
 860   MsgsendMap::iterator pos;
 861   pos = m_msgSend_map.find(curr_pc);
 862   if (pos != m_msgSend_map.end()) {
 863     this_dispatch = g_dispatch_functions[(*pos).second];
 864     found_it = true;
 865   }
 866
 867   // Next check to see if we are in a vtable region:
 868
 869   if (!found_it) {
 870     uint32_t flags;
 871     if (m_vtables_ap.get()) {
 872       found_it = m_vtables_ap->IsAddressInVTables(curr_pc, flags);
 873       if (found_it) {
 874         this_dispatch.name = "vtable";
 875         this_dispatch.stret_return =
 876             (flags & AppleObjCVTables::eOBJC_TRAMPOLINE_STRET) ==
 877             AppleObjCVTables::eOBJC_TRAMPOLINE_STRET;
 878         this_dispatch.is_super = false;
 879         this_dispatch.is_super2 = false;
 880         this_dispatch.fixedup = DispatchFunction::eFixUpFixed;
 881       }
 882     }
 883   }
 884
 885   if (found_it) {
 886     Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
 887
 888     // We are decoding a method dispatch.  First job is to pull the
 889     // arguments out:
 890
 891     lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
 892
 893     const ABI *abi = NULL;
 894     ProcessSP process_sp(thread.CalculateProcess());
 895     if (process_sp)
 896       abi = process_sp->GetABI().get();
 897     if (abi == NULL)
 898       return ret_plan_sp;
 899
 900     TargetSP target_sp(thread.CalculateTarget());
 901
 902     ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext();
 903     ValueList argument_values;
 904     Value void_ptr_value;
 905     CompilerType clang_void_ptr_type =
 906         clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
 907     void_ptr_value.SetValueType(Value::eValueTypeScalar);
 908     // void_ptr_value.SetContext (Value::eContextTypeClangType,
 909     // clang_void_ptr_type);
 910     void_ptr_value.SetCompilerType(clang_void_ptr_type);
 911
 912     int obj_index;
 913     int sel_index;
 914
 915     // If this is a struct return dispatch, then the first argument is
 916     // the return struct pointer, and the object is the second, and
 917     // the selector is the third.  Otherwise the object is the first
 918     // and the selector the second.
 919     if (this_dispatch.stret_return) {
 920       obj_index = 1;
 921       sel_index = 2;
 922       argument_values.PushValue(void_ptr_value);
 923       argument_values.PushValue(void_ptr_value);
 924       argument_values.PushValue(void_ptr_value);
 925     } else {
 926       obj_index = 0;
 927       sel_index = 1;
 928       argument_values.PushValue(void_ptr_value);
 929       argument_values.PushValue(void_ptr_value);
 930     }
 931
 932     bool success = abi->GetArgumentValues(thread, argument_values);
 933     if (!success)
 934       return ret_plan_sp;
 935
 936     lldb::addr_t obj_addr =
 937         argument_values.GetValueAtIndex(obj_index)->GetScalar().ULongLong();
 938     if (obj_addr == 0x0) {
 939       if (log)
 940         log->Printf(
 941             "Asked to step to dispatch to nil object, returning empty plan.");
 942       return ret_plan_sp;
 943     }
 944
 945     ExecutionContext exe_ctx(thread.shared_from_this());
 946     Process *process = exe_ctx.GetProcessPtr();
 947     // isa_addr will store the class pointer that the method is being
 948     // dispatched to - so either the class directly or the super class
 949     // if this is one of the objc_msgSendSuper flavors.  That's mostly
 950     // used to look up the class/selector pair in our cache.
 951
 952     lldb::addr_t isa_addr = LLDB_INVALID_ADDRESS;
 953     lldb::addr_t sel_addr =
 954         argument_values.GetValueAtIndex(sel_index)->GetScalar().ULongLong();
 955
 956     // Figure out the class this is being dispatched to and see if
 957     // we've already cached this method call, If so we can push a
 958     // run-to-address plan directly.  Otherwise we have to figure out
 959     // where the implementation lives.
 960
 961     if (this_dispatch.is_super) {
 962       if (this_dispatch.is_super2) {
 963         // In the objc_msgSendSuper2 case, we don't get the object
 964         // directly, we get a structure containing the object and the
 965         // class to which the super message is being sent.  So we need
 966         // to dig the super out of the class and use that.
 967
 968         Value super_value(*(argument_values.GetValueAtIndex(obj_index)));
 969         super_value.GetScalar() += process->GetAddressByteSize();
 970         super_value.ResolveValue(&exe_ctx);
 971
 972         if (super_value.GetScalar().IsValid()) {
 973
 974           // isa_value now holds the class pointer.  The second word of the
 975           // class pointer is the super-class pointer:
 976           super_value.GetScalar() += process->GetAddressByteSize();
 977           super_value.ResolveValue(&exe_ctx);
 978           if (super_value.GetScalar().IsValid())
 979             isa_addr = super_value.GetScalar().ULongLong();
 980           else {
 981             if (log)
 982               log->Printf("Failed to extract the super class value from the "
 983                           "class in objc_super.");
 984           }
 985         } else {
 986           if (log)
 987             log->Printf("Failed to extract the class value from objc_super.");
 988         }
 989       } else {
 990         // In the objc_msgSendSuper case, we don't get the object
 991         // directly, we get a two element structure containing the
 992         // object and the super class to which the super message is
 993         // being sent.  So the class we want is the second element of
 994         // this structure.
 995
 996         Value super_value(*(argument_values.GetValueAtIndex(obj_index)));
 997         super_value.GetScalar() += process->GetAddressByteSize();
 998         super_value.ResolveValue(&exe_ctx);
 999
1000         if (super_value.GetScalar().IsValid()) {
1001           isa_addr = super_value.GetScalar().ULongLong();
1002         } else {
1003           if (log)
1004             log->Printf("Failed to extract the class value from objc_super.");
1005         }
1006       }
1007     } else {
1008       // In the direct dispatch case, the object->isa is the class pointer we
1009       // want.
1010
1011       // This is a little cheesy, but since object->isa is the first field,
1012       // making the object value a load address value and resolving it will get
1013       // the pointer sized data pointed to by that value...
1014
1015       // Note, it isn't a fatal error not to be able to get the
1016       // address from the object, since this might be a "tagged
1017       // pointer" which isn't a real object, but rather some word
1018       // length encoded dingus.
1019
1020       Value isa_value(*(argument_values.GetValueAtIndex(obj_index)));
1021
1022       isa_value.SetValueType(Value::eValueTypeLoadAddress);
1023       isa_value.ResolveValue(&exe_ctx);
1024       if (isa_value.GetScalar().IsValid()) {
1025         isa_addr = isa_value.GetScalar().ULongLong();
1026       } else {
1027         if (log)
1028           log->Printf("Failed to extract the isa value from object.");
1029       }
1030     }
1031
1032     // Okay, we've got the address of the class for which we're resolving this,
1033     // let's see if it's in our cache:
1034     lldb::addr_t impl_addr = LLDB_INVALID_ADDRESS;
1035
1036     if (isa_addr != LLDB_INVALID_ADDRESS) {
1037       if (log) {
1038         log->Printf("Resolving call for class - 0x%" PRIx64
1039                     " and selector - 0x%" PRIx64,
1040                     isa_addr, sel_addr);
1041       }
1042       ObjCLanguageRuntime *objc_runtime =
1043           thread.GetProcess()->GetObjCLanguageRuntime();
1044       assert(objc_runtime != NULL);
1045
1046       impl_addr = objc_runtime->LookupInMethodCache(isa_addr, sel_addr);
1047     }
1048
1049     if (impl_addr != LLDB_INVALID_ADDRESS) {
1050       // Yup, it was in the cache, so we can run to that address directly.
1051
1052       if (log)
1053         log->Printf("Found implementation address in cache: 0x%" PRIx64,
1054                     impl_addr);
1055
1056       ret_plan_sp.reset(
1057           new ThreadPlanRunToAddress(thread, impl_addr, stop_others));
1058     } else {
1059       // We haven't seen this class/selector pair yet.  Look it up.
1060       StreamString errors;
1061       Address impl_code_address;
1062
1063       ValueList dispatch_values;
1064
1065       // We've will inject a little function in the target that takes the
1066       // object, selector and some flags,
1067       // and figures out the implementation.  Looks like:
1068       //      void *__lldb_objc_find_implementation_for_selector (void *object,
1069       //                                                          void *sel,
1070       //                                                          int is_stret,
1071       //                                                          int is_super,
1072       //                                                          int is_super2,
1073       //                                                          int is_fixup,
1074       //                                                          int is_fixed,
1075       //                                                          int debug)
1076       // So set up the arguments for that call.
1077
1078       dispatch_values.PushValue(*(argument_values.GetValueAtIndex(obj_index)));
1079       dispatch_values.PushValue(*(argument_values.GetValueAtIndex(sel_index)));
1080
1081       Value flag_value;
1082       CompilerType clang_int_type =
1083           clang_ast_context->GetBuiltinTypeForEncodingAndBitSize(
1084               lldb::eEncodingSint, 32);
1085       flag_value.SetValueType(Value::eValueTypeScalar);
1086       // flag_value.SetContext (Value::eContextTypeClangType, clang_int_type);
1087       flag_value.SetCompilerType(clang_int_type);
1088
1089       if (this_dispatch.stret_return)
1090         flag_value.GetScalar() = 1;
1091       else
1092         flag_value.GetScalar() = 0;
1093       dispatch_values.PushValue(flag_value);
1094
1095       if (this_dispatch.is_super)
1096         flag_value.GetScalar() = 1;
1097       else
1098         flag_value.GetScalar() = 0;
1099       dispatch_values.PushValue(flag_value);
1100
1101       if (this_dispatch.is_super2)
1102         flag_value.GetScalar() = 1;
1103       else
1104         flag_value.GetScalar() = 0;
1105       dispatch_values.PushValue(flag_value);
1106
1107       switch (this_dispatch.fixedup) {
1108       case DispatchFunction::eFixUpNone:
1109         flag_value.GetScalar() = 0;
1110         dispatch_values.PushValue(flag_value);
1111         dispatch_values.PushValue(flag_value);
1112         break;
1113       case DispatchFunction::eFixUpFixed:
1114         flag_value.GetScalar() = 1;
1115         dispatch_values.PushValue(flag_value);
1116         flag_value.GetScalar() = 1;
1117         dispatch_values.PushValue(flag_value);
1118         break;
1119       case DispatchFunction::eFixUpToFix:
1120         flag_value.GetScalar() = 1;
1121         dispatch_values.PushValue(flag_value);
1122         flag_value.GetScalar() = 0;
1123         dispatch_values.PushValue(flag_value);
1124         break;
1125       }
1126       if (log && log->GetVerbose())
1127         flag_value.GetScalar() = 1;
1128       else
1129         flag_value.GetScalar() = 0; // FIXME - Set to 0 when debugging is done.
1130       dispatch_values.PushValue(flag_value);
1131
1132       // The step through code might have to fill in the cache, so it
1133       // is not safe to run only one thread.  So we override the
1134       // stop_others value passed in to us here:
1135       const bool trampoline_stop_others = false;
1136       ret_plan_sp.reset(new AppleThreadPlanStepThroughObjCTrampoline(
1137           thread, this, dispatch_values, isa_addr, sel_addr,
1138           trampoline_stop_others));
1139       if (log) {
1140         StreamString s;
1141         ret_plan_sp->GetDescription(&s, eDescriptionLevelFull);
1142         log->Printf("Using ObjC step plan: %s.\n", s.GetData());
1143       }
1144     }
1145   }
1146
1147   return ret_plan_sp;
1148 }
1149
1150 FunctionCaller *
1151 AppleObjCTrampolineHandler::GetLookupImplementationFunctionCaller() {
1152   return m_impl_code->GetFunctionCaller();
1153 }