AppleObjCRuntimeV2.h

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//===-- AppleObjCRuntimeV2.h ------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
#ifndef LLDB_SOURCE_PLUGINS_LANGUAGERUNTIME_OBJC_APPLEOBJCRUNTIME_APPLEOBJCRUNTIMEV2_H
#define LLDB_SOURCE_PLUGINS_LANGUAGERUNTIME_OBJC_APPLEOBJCRUNTIME_APPLEOBJCRUNTIMEV2_H
 
#include <map>
#include <memory>
#include <mutex>
#include <optional>
 
#include "AppleObjCRuntime.h"
#include "lldb/lldb-private.h"
 
#include "Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h"
 
class RemoteNXMapTable;
 
namespace lldb_private {
 
class AppleObjCRuntimeV2 : public AppleObjCRuntime {
public:
  ~AppleObjCRuntimeV2() override = default;
 
  static void Initialize();
 
  static void Terminate();
 
  static lldb_private::LanguageRuntime *
  CreateInstance(Process *process, lldb::LanguageType language);
 
  static llvm::StringRef GetPluginNameStatic() { return "apple-objc-v2"; }
 
  static char ID;
 
  bool isA(const void *ClassID) const override {
    return ClassID == &ID || AppleObjCRuntime::isA(ClassID);
  }
 
  static bool classof(const LanguageRuntime *runtime) {
    return runtime->isA(&ID);
  }
 
  bool GetDynamicTypeAndAddress(ValueObject &in_value,
                                lldb::DynamicValueType use_dynamic,
                                TypeAndOrName &class_type_or_name,
                                Address &address,
                                Value::ValueType &value_type) override;
 
  llvm::Expected<std::unique_ptr<UtilityFunction>>
  CreateObjectChecker(std::string name, ExecutionContext &exe_ctx) override;
 
  llvm::StringRef GetPluginName() override { return GetPluginNameStatic(); }
 
  ObjCRuntimeVersions GetRuntimeVersion() const override {
    return ObjCRuntimeVersions::eAppleObjC_V2;
  }
 
  size_t GetByteOffsetForIvar(CompilerType &parent_qual_type,
                              const char *ivar_name) override;
 
  void UpdateISAToDescriptorMapIfNeeded() override;
 
  ClassDescriptorSP GetClassDescriptor(ValueObject &in_value) override;
 
  ClassDescriptorSP GetClassDescriptorFromISA(ObjCISA isa) override;
 
  DeclVendor *GetDeclVendor() override;
 
  lldb::addr_t LookupRuntimeSymbol(ConstString name) override;
 
  EncodingToTypeSP GetEncodingToType() override;
 
  bool IsTaggedPointer(lldb::addr_t ptr) override;
 
  TaggedPointerVendor *GetTaggedPointerVendor() override {
    return m_tagged_pointer_vendor_up.get();
  }
 
  lldb::addr_t GetTaggedPointerObfuscator();
 
  /// Returns the base address for relative method list selector strings.
  lldb::addr_t GetRelativeSelectorBaseAddr() {
    return m_relative_selector_base;
  }
 
  void SetRelativeSelectorBaseAddr(lldb::addr_t relative_selector_base) {
    m_relative_selector_base = relative_selector_base;
  }
 
  void GetValuesForGlobalCFBooleans(lldb::addr_t &cf_true,
                                    lldb::addr_t &cf_false) override;
 
  // none of these are valid ISAs - we use them to infer the type
  // of tagged pointers - if we have something meaningful to say
  // we report an actual type - otherwise, we just say tagged
  // there is no connection between the values here and the tagged pointers map
  static const ObjCLanguageRuntime::ObjCISA g_objc_Tagged_ISA = 1;
  static const ObjCLanguageRuntime::ObjCISA g_objc_Tagged_ISA_NSAtom = 2;
  static const ObjCLanguageRuntime::ObjCISA g_objc_Tagged_ISA_NSNumber = 3;
  static const ObjCLanguageRuntime::ObjCISA g_objc_Tagged_ISA_NSDateTS = 4;
  static const ObjCLanguageRuntime::ObjCISA g_objc_Tagged_ISA_NSManagedObject =
      5;
  static const ObjCLanguageRuntime::ObjCISA g_objc_Tagged_ISA_NSDate = 6;
 
protected:
  lldb::BreakpointResolverSP
  CreateExceptionResolver(const lldb::BreakpointSP &bkpt, bool catch_bp,
                          bool throw_bp) override;
 
private:
  class HashTableSignature {
  public:
    HashTableSignature();
 
    bool NeedsUpdate(Process *process, AppleObjCRuntimeV2 *runtime,
                     RemoteNXMapTable &hash_table);
 
    void UpdateSignature(const RemoteNXMapTable &hash_table);
 
  protected:
    uint32_t m_count = 0;
    uint32_t m_num_buckets = 0;
    lldb::addr_t m_buckets_ptr = 0;
  };
 
  class NonPointerISACache {
  public:
    static NonPointerISACache *
    CreateInstance(AppleObjCRuntimeV2 &runtime,
                   const lldb::ModuleSP &objc_module_sp);
 
    ObjCLanguageRuntime::ClassDescriptorSP GetClassDescriptor(ObjCISA isa);
 
  private:
    NonPointerISACache(AppleObjCRuntimeV2 &runtime,
                       const lldb::ModuleSP &objc_module_sp,
                       uint64_t objc_debug_isa_class_mask,
                       uint64_t objc_debug_isa_magic_mask,
                       uint64_t objc_debug_isa_magic_value,
                       uint64_t objc_debug_indexed_isa_magic_mask,
                       uint64_t objc_debug_indexed_isa_magic_value,
                       uint64_t objc_debug_indexed_isa_index_mask,
                       uint64_t objc_debug_indexed_isa_index_shift,
                       lldb::addr_t objc_indexed_classes);
 
    bool EvaluateNonPointerISA(ObjCISA isa, ObjCISA &ret_isa);
 
    AppleObjCRuntimeV2 &m_runtime;
    std::map<ObjCISA, ObjCLanguageRuntime::ClassDescriptorSP> m_cache;
    lldb::ModuleWP m_objc_module_wp;
    uint64_t m_objc_debug_isa_class_mask;
    uint64_t m_objc_debug_isa_magic_mask;
    uint64_t m_objc_debug_isa_magic_value;
 
    uint64_t m_objc_debug_indexed_isa_magic_mask;
    uint64_t m_objc_debug_indexed_isa_magic_value;
    uint64_t m_objc_debug_indexed_isa_index_mask;
    uint64_t m_objc_debug_indexed_isa_index_shift;
    lldb::addr_t m_objc_indexed_classes;
 
    std::vector<lldb::addr_t> m_indexed_isa_cache;
 
    friend class AppleObjCRuntimeV2;
 
    NonPointerISACache(const NonPointerISACache &) = delete;
    const NonPointerISACache &operator=(const NonPointerISACache &) = delete;
  };
 
  class TaggedPointerVendorV2
      : public ObjCLanguageRuntime::TaggedPointerVendor {
  public:
    ~TaggedPointerVendorV2() override = default;
 
    static TaggedPointerVendorV2 *
    CreateInstance(AppleObjCRuntimeV2 &runtime,
                   const lldb::ModuleSP &objc_module_sp);
 
  protected:
    AppleObjCRuntimeV2 &m_runtime;
 
    TaggedPointerVendorV2(AppleObjCRuntimeV2 &runtime)
        : TaggedPointerVendor(), m_runtime(runtime) {}
 
  private:
    TaggedPointerVendorV2(const TaggedPointerVendorV2 &) = delete;
    const TaggedPointerVendorV2 &
    operator=(const TaggedPointerVendorV2 &) = delete;
  };
 
  class TaggedPointerVendorRuntimeAssisted : public TaggedPointerVendorV2 {
  public:
    bool IsPossibleTaggedPointer(lldb::addr_t ptr) override;
 
    ObjCLanguageRuntime::ClassDescriptorSP
    GetClassDescriptor(lldb::addr_t ptr) override;
 
  protected:
    TaggedPointerVendorRuntimeAssisted(
        AppleObjCRuntimeV2 &runtime, uint64_t objc_debug_taggedpointer_mask,
        uint32_t objc_debug_taggedpointer_slot_shift,
        uint32_t objc_debug_taggedpointer_slot_mask,
        uint32_t objc_debug_taggedpointer_payload_lshift,
        uint32_t objc_debug_taggedpointer_payload_rshift,
        lldb::addr_t objc_debug_taggedpointer_classes);
 
    typedef std::map<uint8_t, ObjCLanguageRuntime::ClassDescriptorSP> Cache;
    typedef Cache::iterator CacheIterator;
    Cache m_cache;
    uint64_t m_objc_debug_taggedpointer_mask;
    uint32_t m_objc_debug_taggedpointer_slot_shift;
    uint32_t m_objc_debug_taggedpointer_slot_mask;
    uint32_t m_objc_debug_taggedpointer_payload_lshift;
    uint32_t m_objc_debug_taggedpointer_payload_rshift;
    lldb::addr_t m_objc_debug_taggedpointer_classes;
 
    friend class AppleObjCRuntimeV2::TaggedPointerVendorV2;
 
    TaggedPointerVendorRuntimeAssisted(
        const TaggedPointerVendorRuntimeAssisted &) = delete;
    const TaggedPointerVendorRuntimeAssisted &
    operator=(const TaggedPointerVendorRuntimeAssisted &) = delete;
  };
 
  class TaggedPointerVendorExtended
      : public TaggedPointerVendorRuntimeAssisted {
  public:
    ObjCLanguageRuntime::ClassDescriptorSP
    GetClassDescriptor(lldb::addr_t ptr) override;
 
  protected:
    TaggedPointerVendorExtended(
        AppleObjCRuntimeV2 &runtime, uint64_t objc_debug_taggedpointer_mask,
        uint64_t objc_debug_taggedpointer_ext_mask,
        uint32_t objc_debug_taggedpointer_slot_shift,
        uint32_t objc_debug_taggedpointer_ext_slot_shift,
        uint32_t objc_debug_taggedpointer_slot_mask,
        uint32_t objc_debug_taggedpointer_ext_slot_mask,
        uint32_t objc_debug_taggedpointer_payload_lshift,
        uint32_t objc_debug_taggedpointer_payload_rshift,
        uint32_t objc_debug_taggedpointer_ext_payload_lshift,
        uint32_t objc_debug_taggedpointer_ext_payload_rshift,
        lldb::addr_t objc_debug_taggedpointer_classes,
        lldb::addr_t objc_debug_taggedpointer_ext_classes);
 
    bool IsPossibleExtendedTaggedPointer(lldb::addr_t ptr);
 
    typedef std::map<uint8_t, ObjCLanguageRuntime::ClassDescriptorSP> Cache;
    typedef Cache::iterator CacheIterator;
    Cache m_ext_cache;
    uint64_t m_objc_debug_taggedpointer_ext_mask;
    uint32_t m_objc_debug_taggedpointer_ext_slot_shift;
    uint32_t m_objc_debug_taggedpointer_ext_slot_mask;
    uint32_t m_objc_debug_taggedpointer_ext_payload_lshift;
    uint32_t m_objc_debug_taggedpointer_ext_payload_rshift;
    lldb::addr_t m_objc_debug_taggedpointer_ext_classes;
 
    friend class AppleObjCRuntimeV2::TaggedPointerVendorV2;
 
    TaggedPointerVendorExtended(const TaggedPointerVendorExtended &) = delete;
    const TaggedPointerVendorExtended &
    operator=(const TaggedPointerVendorExtended &) = delete;
  };
 
  class TaggedPointerVendorLegacy : public TaggedPointerVendorV2 {
  public:
    bool IsPossibleTaggedPointer(lldb::addr_t ptr) override;
 
    ObjCLanguageRuntime::ClassDescriptorSP
    GetClassDescriptor(lldb::addr_t ptr) override;
 
  protected:
    TaggedPointerVendorLegacy(AppleObjCRuntimeV2 &runtime)
        : TaggedPointerVendorV2(runtime) {}
 
    friend class AppleObjCRuntimeV2::TaggedPointerVendorV2;
 
    TaggedPointerVendorLegacy(const TaggedPointerVendorLegacy &) = delete;
    const TaggedPointerVendorLegacy &
    operator=(const TaggedPointerVendorLegacy &) = delete;
  };
 
  struct DescriptorMapUpdateResult {
    bool m_update_ran;
    bool m_retry_update;
    uint32_t m_num_found;
 
    DescriptorMapUpdateResult(bool ran, bool retry, uint32_t found) {
      m_update_ran = ran;
 
      m_retry_update = retry;
 
      m_num_found = found;
    }
 
    static DescriptorMapUpdateResult Fail() { return {false, false, 0}; }
 
    static DescriptorMapUpdateResult Success(uint32_t found) {
      return {true, false, found};
    }
 
    static DescriptorMapUpdateResult Retry() { return {false, true, 0}; }
  };
 
  /// Abstraction to read the Objective-C class info.
  class ClassInfoExtractor {
  public:
    ClassInfoExtractor(AppleObjCRuntimeV2 &runtime) : m_runtime(runtime) {}
    std::mutex &GetMutex() { return m_mutex; }
 
  protected:
    /// The lifetime of this object is tied to that of the runtime.
    AppleObjCRuntimeV2 &m_runtime;
    std::mutex m_mutex;
  };
 
  /// We can read the class info from the Objective-C runtime using
  /// gdb_objc_realized_classes, objc_copyRealizedClassList or
  /// objc_getRealizedClassList_trylock. The RealizedClassList variants are
  /// preferred because they include lazily named classes, but they are not
  /// always available or safe to call.
  ///
  /// We potentially need more than one helper for the same process, because we
  /// may need to use gdb_objc_realized_classes until dyld is initialized and
  /// then switch over to objc_copyRealizedClassList or
  /// objc_getRealizedClassList_trylock for lazily named classes.
  class DynamicClassInfoExtractor : public ClassInfoExtractor {
  public:
    DynamicClassInfoExtractor(AppleObjCRuntimeV2 &runtime)
        : ClassInfoExtractor(runtime) {}
 
    DescriptorMapUpdateResult
    UpdateISAToDescriptorMap(RemoteNXMapTable &hash_table);
 
  private:
    enum Helper {
      gdb_objc_realized_classes,
      objc_copyRealizedClassList,
      objc_getRealizedClassList_trylock
    };
 
    /// Compute which helper to use. If dyld is not yet fully initialized we
    /// must use gdb_objc_realized_classes. Otherwise, we prefer
    /// objc_getRealizedClassList_trylock and objc_copyRealizedClassList
    /// respectively, depending on availability.
    Helper ComputeHelper(ExecutionContext &exe_ctx) const;
 
    UtilityFunction *GetClassInfoUtilityFunction(ExecutionContext &exe_ctx,
                                                 Helper helper);
    lldb::addr_t &GetClassInfoArgs(Helper helper);
 
    std::unique_ptr<UtilityFunction>
    GetClassInfoUtilityFunctionImpl(ExecutionContext &exe_ctx, Helper helper,
                                    std::string code, std::string name);
 
    struct UtilityFunctionHelper {
      std::unique_ptr<UtilityFunction> utility_function;
      lldb::addr_t args = LLDB_INVALID_ADDRESS;
    };
 
    UtilityFunctionHelper m_gdb_objc_realized_classes_helper;
    UtilityFunctionHelper m_objc_copyRealizedClassList_helper;
    UtilityFunctionHelper m_objc_getRealizedClassList_trylock_helper;
  };
 
  /// Abstraction to read the Objective-C class info from the shared cache.
  class SharedCacheClassInfoExtractor : public ClassInfoExtractor {
  public:
    SharedCacheClassInfoExtractor(AppleObjCRuntimeV2 &runtime)
        : ClassInfoExtractor(runtime) {}
 
    DescriptorMapUpdateResult UpdateISAToDescriptorMap();
 
  private:
    UtilityFunction *GetClassInfoUtilityFunction(ExecutionContext &exe_ctx);
 
    std::unique_ptr<UtilityFunction>
    GetClassInfoUtilityFunctionImpl(ExecutionContext &exe_ctx);
 
    std::unique_ptr<UtilityFunction> m_utility_function;
    lldb::addr_t m_args = LLDB_INVALID_ADDRESS;
  };
 
  AppleObjCRuntimeV2(Process *process, const lldb::ModuleSP &objc_module_sp);
 
  ObjCISA GetPointerISA(ObjCISA isa);
 
  lldb::addr_t GetISAHashTablePointer();
 
  /// Update the generation count of realized classes. This is not an exact
  /// count but rather a value that is incremented when new classes are realized
  /// or destroyed. Unlike the count in gdb_objc_realized_classes, it will
  /// change when lazily named classes get realized.
  bool RealizedClassGenerationCountChanged();
 
  uint32_t ParseClassInfoArray(const lldb_private::DataExtractor &data,
                               uint32_t num_class_infos);
 
  enum class SharedCacheWarningReason {
    eExpressionUnableToRun,
    eExpressionExecutionFailure,
    eNotEnoughClassesRead
  };
 
  void WarnIfNoClassesCached(SharedCacheWarningReason reason);
  void WarnIfNoExpandedSharedCache();
 
  lldb::addr_t GetSharedCacheReadOnlyAddress();
  lldb::addr_t GetSharedCacheBaseAddress();
 
  bool GetCFBooleanValuesIfNeeded();
 
  bool HasSymbol(ConstString Name);
 
  NonPointerISACache *GetNonPointerIsaCache() {
    if (!m_non_pointer_isa_cache_up)
      m_non_pointer_isa_cache_up.reset(
          NonPointerISACache::CreateInstance(*this, m_objc_module_sp));
    return m_non_pointer_isa_cache_up.get();
  }
 
  friend class ClassDescriptorV2;
 
  lldb::ModuleSP m_objc_module_sp;
 
  DynamicClassInfoExtractor m_dynamic_class_info_extractor;
  SharedCacheClassInfoExtractor m_shared_cache_class_info_extractor;
 
  std::unique_ptr<DeclVendor> m_decl_vendor_up;
  lldb::addr_t m_tagged_pointer_obfuscator;
  lldb::addr_t m_isa_hash_table_ptr;
  lldb::addr_t m_relative_selector_base;
  HashTableSignature m_hash_signature;
  bool m_has_object_getClass;
  bool m_has_objc_copyRealizedClassList;
  bool m_has_objc_getRealizedClassList_trylock;
  bool m_loaded_objc_opt;
  std::unique_ptr<NonPointerISACache> m_non_pointer_isa_cache_up;
  std::unique_ptr<TaggedPointerVendor> m_tagged_pointer_vendor_up;
  EncodingToTypeSP m_encoding_to_type_sp;
  std::once_flag m_no_classes_cached_warning;
  std::once_flag m_no_expanded_cache_warning;
  std::optional<std::pair<lldb::addr_t, lldb::addr_t>> m_CFBoolean_values;
  uint64_t m_realized_class_generation_count;
};
 
} // namespace lldb_private
 
#endif // LLDB_SOURCE_PLUGINS_LANGUAGERUNTIME_OBJC_APPLEOBJCRUNTIME_APPLEOBJCRUNTIMEV2_H