contrib/llvm/tools/lldb/source/Plugins/Language/ObjC/NSError.cpp

   1 //===-- NSError.cpp ---------------------------------------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 // C Includes
  11 // C++ Includes
  12 // Other libraries and framework includes
  13 #include "clang/AST/DeclCXX.h"
  14
  15 // Project includes
  16 #include "Cocoa.h"
  17
  18 #include "lldb/Core/ValueObject.h"
  19 #include "lldb/Core/ValueObjectConstResult.h"
  20 #include "lldb/DataFormatters/FormattersHelpers.h"
  21 #include "lldb/Symbol/ClangASTContext.h"
  22 #include "lldb/Target/ObjCLanguageRuntime.h"
  23 #include "lldb/Target/ProcessStructReader.h"
  24 #include "lldb/Target/Target.h"
  25 #include "lldb/Utility/DataBufferHeap.h"
  26 #include "lldb/Utility/Endian.h"
  27 #include "lldb/Utility/Status.h"
  28 #include "lldb/Utility/Stream.h"
  29
  30 #include "Plugins/Language/ObjC/NSString.h"
  31
  32 using namespace lldb;
  33 using namespace lldb_private;
  34 using namespace lldb_private::formatters;
  35
  36 static lldb::addr_t DerefToNSErrorPointer(ValueObject &valobj) {
  37   CompilerType valobj_type(valobj.GetCompilerType());
  38   Flags type_flags(valobj_type.GetTypeInfo());
  39   if (type_flags.AllClear(eTypeHasValue)) {
  40     if (valobj.IsBaseClass() && valobj.GetParent())
  41       return valobj.GetParent()->GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
  42   } else {
  43     lldb::addr_t ptr_value = valobj.GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
  44     if (type_flags.AllSet(eTypeIsPointer)) {
  45       CompilerType pointee_type(valobj_type.GetPointeeType());
  46       Flags pointee_flags(pointee_type.GetTypeInfo());
  47       if (pointee_flags.AllSet(eTypeIsPointer)) {
  48         if (ProcessSP process_sp = valobj.GetProcessSP()) {
  49           Status error;
  50           ptr_value = process_sp->ReadPointerFromMemory(ptr_value, error);
  51         }
  52       }
  53     }
  54     return ptr_value;
  55   }
  56
  57   return LLDB_INVALID_ADDRESS;
  58 }
  59
  60 bool lldb_private::formatters::NSError_SummaryProvider(
  61     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
  62   ProcessSP process_sp(valobj.GetProcessSP());
  63   if (!process_sp)
  64     return false;
  65
  66   lldb::addr_t ptr_value = DerefToNSErrorPointer(valobj);
  67   if (ptr_value == LLDB_INVALID_ADDRESS)
  68     return false;
  69
  70   size_t ptr_size = process_sp->GetAddressByteSize();
  71   lldb::addr_t code_location = ptr_value + 2 * ptr_size;
  72   lldb::addr_t domain_location = ptr_value + 3 * ptr_size;
  73
  74   Status error;
  75   uint64_t code = process_sp->ReadUnsignedIntegerFromMemory(code_location,
  76                                                             ptr_size, 0, error);
  77   if (error.Fail())
  78     return false;
  79
  80   lldb::addr_t domain_str_value =
  81       process_sp->ReadPointerFromMemory(domain_location, error);
  82   if (error.Fail() || domain_str_value == LLDB_INVALID_ADDRESS)
  83     return false;
  84
  85   if (!domain_str_value) {
  86     stream.Printf("domain: nil - code: %" PRIu64, code);
  87     return true;
  88   }
  89
  90   InferiorSizedWord isw(domain_str_value, *process_sp);
  91
  92   ValueObjectSP domain_str_sp = ValueObject::CreateValueObjectFromData(
  93       "domain_str", isw.GetAsData(process_sp->GetByteOrder()),
  94       valobj.GetExecutionContextRef(), process_sp->GetTarget()
  95                                            .GetScratchClangASTContext()
  96                                            ->GetBasicType(lldb::eBasicTypeVoid)
  97                                            .GetPointerType());
  98
  99   if (!domain_str_sp)
 100     return false;
 101
 102   StreamString domain_str_summary;
 103   if (NSStringSummaryProvider(*domain_str_sp, domain_str_summary, options) &&
 104       !domain_str_summary.Empty()) {
 105     stream.Printf("domain: %s - code: %" PRIu64, domain_str_summary.GetData(),
 106                   code);
 107     return true;
 108   } else {
 109     stream.Printf("domain: nil - code: %" PRIu64, code);
 110     return true;
 111   }
 112 }
 113
 114 class NSErrorSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
 115 public:
 116   NSErrorSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
 117       : SyntheticChildrenFrontEnd(*valobj_sp) {}
 118
 119   ~NSErrorSyntheticFrontEnd() override = default;
 120   // no need to delete m_child_ptr - it's kept alive by the cluster manager on
 121   // our behalf
 122
 123   size_t CalculateNumChildren() override {
 124     if (m_child_ptr)
 125       return 1;
 126     if (m_child_sp)
 127       return 1;
 128     return 0;
 129   }
 130
 131   lldb::ValueObjectSP GetChildAtIndex(size_t idx) override {
 132     if (idx != 0)
 133       return lldb::ValueObjectSP();
 134
 135     if (m_child_ptr)
 136       return m_child_ptr->GetSP();
 137     return m_child_sp;
 138   }
 139
 140   bool Update() override {
 141     m_child_ptr = nullptr;
 142     m_child_sp.reset();
 143
 144     ProcessSP process_sp(m_backend.GetProcessSP());
 145     if (!process_sp)
 146       return false;
 147
 148     lldb::addr_t userinfo_location = DerefToNSErrorPointer(m_backend);
 149     if (userinfo_location == LLDB_INVALID_ADDRESS)
 150       return false;
 151
 152     size_t ptr_size = process_sp->GetAddressByteSize();
 153
 154     userinfo_location += 4 * ptr_size;
 155     Status error;
 156     lldb::addr_t userinfo =
 157         process_sp->ReadPointerFromMemory(userinfo_location, error);
 158     if (userinfo == LLDB_INVALID_ADDRESS || error.Fail())
 159       return false;
 160     InferiorSizedWord isw(userinfo, *process_sp);
 161     m_child_sp = CreateValueObjectFromData(
 162         "_userInfo", isw.GetAsData(process_sp->GetByteOrder()),
 163         m_backend.GetExecutionContextRef(),
 164         process_sp->GetTarget().GetScratchClangASTContext()->GetBasicType(
 165             lldb::eBasicTypeObjCID));
 166     return false;
 167   }
 168
 169   bool MightHaveChildren() override { return true; }
 170
 171   size_t GetIndexOfChildWithName(const ConstString &name) override {
 172     static ConstString g___userInfo("_userInfo");
 173     if (name == g___userInfo)
 174       return 0;
 175     return UINT32_MAX;
 176   }
 177
 178 private:
 179   // the child here can be "real" (i.e. an actual child of the root) or
 180   // synthetized from raw memory if the former, I need to store a plain pointer
 181   // to it - or else a loop of references will cause this entire hierarchy of
 182   // values to leak if the latter, then I need to store a SharedPointer to it -
 183   // so that it only goes away when everyone else in the cluster goes away oh
 184   // joy!
 185   ValueObject *m_child_ptr;
 186   ValueObjectSP m_child_sp;
 187 };
 188
 189 SyntheticChildrenFrontEnd *
 190 lldb_private::formatters::NSErrorSyntheticFrontEndCreator(
 191     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
 192   lldb::ProcessSP process_sp(valobj_sp->GetProcessSP());
 193   if (!process_sp)
 194     return nullptr;
 195   ObjCLanguageRuntime *runtime =
 196       (ObjCLanguageRuntime *)process_sp->GetLanguageRuntime(
 197           lldb::eLanguageTypeObjC);
 198   if (!runtime)
 199     return nullptr;
 200
 201   ObjCLanguageRuntime::ClassDescriptorSP descriptor(
 202       runtime->GetClassDescriptor(*valobj_sp.get()));
 203
 204   if (!descriptor.get() || !descriptor->IsValid())
 205     return nullptr;
 206
 207   const char *class_name = descriptor->GetClassName().GetCString();
 208
 209   if (!class_name || !*class_name)
 210     return nullptr;
 211
 212   if (!strcmp(class_name, "NSError"))
 213     return (new NSErrorSyntheticFrontEnd(valobj_sp));
 214   else if (!strcmp(class_name, "__NSCFError"))
 215     return (new NSErrorSyntheticFrontEnd(valobj_sp));
 216
 217   return nullptr;
 218 }