Files
clang-p2996/lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.cpp
Jonas Devlieghere 5e9f247c06 [lldb] Make LanguageRuntime::GetTypeBitSize return an optional (NFC) (#96013)
Make LanguageRuntime::GetTypeBitSize return an optional. This should be
NFC, though the ObjCLanguageRuntime implementation is (possibly) more
defensive against returning 0.

I'm not sure if it's possible for both `m_ivar.size` and `m_ivar.offset`
to be zero. Previously, we'd return 0 and cache it, only to discard it
the next time when finding it in the cache, and recomputing it again.
The new code will avoid putting it in the cache in the first place.
2024-06-20 10:46:26 -07:00

460 lines
15 KiB
C++

//===-- ObjCLanguageRuntime.cpp -------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "clang/AST/Type.h"
#include "ObjCLanguageRuntime.h"
#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Symbol/SymbolFile.h"
#include "lldb/Symbol/Type.h"
#include "lldb/Symbol/TypeList.h"
#include "lldb/Symbol/Variable.h"
#include "lldb/Target/ABI.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/LLDBLog.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/Timer.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/DJB.h"
#include <optional>
using namespace lldb;
using namespace lldb_private;
char ObjCLanguageRuntime::ID = 0;
// Destructor
ObjCLanguageRuntime::~ObjCLanguageRuntime() = default;
ObjCLanguageRuntime::ObjCLanguageRuntime(Process *process)
: LanguageRuntime(process), m_impl_cache(), m_impl_str_cache(),
m_has_new_literals_and_indexing(eLazyBoolCalculate),
m_isa_to_descriptor(), m_hash_to_isa_map(), m_type_size_cache(),
m_isa_to_descriptor_stop_id(UINT32_MAX), m_complete_class_cache(),
m_negative_complete_class_cache() {}
bool ObjCLanguageRuntime::IsAllowedRuntimeValue(ConstString name) {
static ConstString g_self = ConstString("self");
static ConstString g_cmd = ConstString("_cmd");
return name == g_self || name == g_cmd;
}
bool ObjCLanguageRuntime::AddClass(ObjCISA isa,
const ClassDescriptorSP &descriptor_sp,
const char *class_name) {
if (isa != 0) {
m_isa_to_descriptor[isa] = descriptor_sp;
// class_name is assumed to be valid
m_hash_to_isa_map.insert(std::make_pair(llvm::djbHash(class_name), isa));
return true;
}
return false;
}
void ObjCLanguageRuntime::AddToMethodCache(lldb::addr_t class_addr,
lldb::addr_t selector,
lldb::addr_t impl_addr) {
Log *log = GetLog(LLDBLog::Step);
if (log) {
LLDB_LOGF(log,
"Caching: class 0x%" PRIx64 " selector 0x%" PRIx64
" implementation 0x%" PRIx64 ".",
class_addr, selector, impl_addr);
}
m_impl_cache.insert(std::pair<ClassAndSel, lldb::addr_t>(
ClassAndSel(class_addr, selector), impl_addr));
}
void ObjCLanguageRuntime::AddToMethodCache(lldb::addr_t class_addr,
llvm::StringRef sel_str,
lldb::addr_t impl_addr) {
Log *log = GetLog(LLDBLog::Step);
LLDB_LOG(log, "Caching: class {0} selector {1} implementation {2}.",
class_addr, sel_str, impl_addr);
m_impl_str_cache.insert(std::pair<ClassAndSelStr, lldb::addr_t>(
ClassAndSelStr(class_addr, sel_str), impl_addr));
}
lldb::addr_t ObjCLanguageRuntime::LookupInMethodCache(lldb::addr_t class_addr,
lldb::addr_t selector) {
MsgImplMap::iterator pos, end = m_impl_cache.end();
pos = m_impl_cache.find(ClassAndSel(class_addr, selector));
if (pos != end)
return (*pos).second;
return LLDB_INVALID_ADDRESS;
}
lldb::addr_t ObjCLanguageRuntime::LookupInMethodCache(lldb::addr_t class_addr,
llvm::StringRef sel_str) {
MsgImplStrMap::iterator pos, end = m_impl_str_cache.end();
pos = m_impl_str_cache.find(ClassAndSelStr(class_addr, sel_str));
if (pos != end)
return (*pos).second;
return LLDB_INVALID_ADDRESS;
}
lldb::TypeSP
ObjCLanguageRuntime::LookupInCompleteClassCache(ConstString &name) {
CompleteClassMap::iterator complete_class_iter =
m_complete_class_cache.find(name);
if (complete_class_iter != m_complete_class_cache.end()) {
// Check the weak pointer to make sure the type hasn't been unloaded
TypeSP complete_type_sp(complete_class_iter->second.lock());
if (complete_type_sp)
return complete_type_sp;
else
m_complete_class_cache.erase(name);
}
if (m_negative_complete_class_cache.count(name) > 0)
return TypeSP();
const ModuleList &modules = m_process->GetTarget().GetImages();
SymbolContextList sc_list;
modules.FindSymbolsWithNameAndType(name, eSymbolTypeObjCClass, sc_list);
const size_t matching_symbols = sc_list.GetSize();
if (matching_symbols) {
SymbolContext sc;
sc_list.GetContextAtIndex(0, sc);
ModuleSP module_sp(sc.module_sp);
if (!module_sp)
return TypeSP();
TypeQuery query(name.GetStringRef(), TypeQueryOptions::e_exact_match);
TypeResults results;
module_sp->FindTypes(query, results);
for (const TypeSP &type_sp : results.GetTypeMap().Types()) {
if (TypeSystemClang::IsObjCObjectOrInterfaceType(
type_sp->GetForwardCompilerType())) {
if (TypePayloadClang(type_sp->GetPayload()).IsCompleteObjCClass()) {
m_complete_class_cache[name] = type_sp;
return type_sp;
}
}
}
}
m_negative_complete_class_cache.insert(name);
return TypeSP();
}
size_t ObjCLanguageRuntime::GetByteOffsetForIvar(CompilerType &parent_qual_type,
const char *ivar_name) {
return LLDB_INVALID_IVAR_OFFSET;
}
bool ObjCLanguageRuntime::ClassDescriptor::IsPointerValid(
lldb::addr_t value, uint32_t ptr_size, bool allow_NULLs, bool allow_tagged,
bool check_version_specific) const {
if (!value)
return allow_NULLs;
if ((value % 2) == 1 && allow_tagged)
return true;
if ((value % ptr_size) == 0)
return (check_version_specific ? CheckPointer(value, ptr_size) : true);
else
return false;
}
ObjCLanguageRuntime::ObjCISA
ObjCLanguageRuntime::GetISA(ConstString name) {
ISAToDescriptorIterator pos = GetDescriptorIterator(name);
if (pos != m_isa_to_descriptor.end())
return pos->first;
return 0;
}
ObjCLanguageRuntime::ISAToDescriptorIterator
ObjCLanguageRuntime::GetDescriptorIterator(ConstString name) {
ISAToDescriptorIterator end = m_isa_to_descriptor.end();
if (name) {
UpdateISAToDescriptorMap();
if (m_hash_to_isa_map.empty()) {
// No name hashes were provided, we need to just linearly power through
// the names and find a match
for (ISAToDescriptorIterator pos = m_isa_to_descriptor.begin();
pos != end; ++pos) {
if (pos->second->GetClassName() == name)
return pos;
}
} else {
// Name hashes were provided, so use them to efficiently lookup name to
// isa/descriptor
const uint32_t name_hash = llvm::djbHash(name.GetStringRef());
std::pair<HashToISAIterator, HashToISAIterator> range =
m_hash_to_isa_map.equal_range(name_hash);
for (HashToISAIterator range_pos = range.first; range_pos != range.second;
++range_pos) {
ISAToDescriptorIterator pos =
m_isa_to_descriptor.find(range_pos->second);
if (pos != m_isa_to_descriptor.end()) {
if (pos->second->GetClassName() == name)
return pos;
}
}
}
}
return end;
}
std::pair<ObjCLanguageRuntime::ISAToDescriptorIterator,
ObjCLanguageRuntime::ISAToDescriptorIterator>
ObjCLanguageRuntime::GetDescriptorIteratorPair(bool update_if_needed) {
if (update_if_needed)
UpdateISAToDescriptorMapIfNeeded();
return std::pair<ObjCLanguageRuntime::ISAToDescriptorIterator,
ObjCLanguageRuntime::ISAToDescriptorIterator>(
m_isa_to_descriptor.begin(), m_isa_to_descriptor.end());
}
void ObjCLanguageRuntime::ReadObjCLibraryIfNeeded(
const ModuleList &module_list) {
if (!HasReadObjCLibrary()) {
std::lock_guard<std::recursive_mutex> guard(module_list.GetMutex());
size_t num_modules = module_list.GetSize();
for (size_t i = 0; i < num_modules; i++) {
auto mod = module_list.GetModuleAtIndex(i);
if (IsModuleObjCLibrary(mod)) {
ReadObjCLibrary(mod);
break;
}
}
}
}
ObjCLanguageRuntime::ObjCISA
ObjCLanguageRuntime::GetParentClass(ObjCLanguageRuntime::ObjCISA isa) {
ClassDescriptorSP objc_class_sp(GetClassDescriptorFromISA(isa));
if (objc_class_sp) {
ClassDescriptorSP objc_super_class_sp(objc_class_sp->GetSuperclass());
if (objc_super_class_sp)
return objc_super_class_sp->GetISA();
}
return 0;
}
ObjCLanguageRuntime::ClassDescriptorSP
ObjCLanguageRuntime::GetClassDescriptorFromClassName(
ConstString class_name) {
ISAToDescriptorIterator pos = GetDescriptorIterator(class_name);
if (pos != m_isa_to_descriptor.end())
return pos->second;
return ClassDescriptorSP();
}
ObjCLanguageRuntime::ClassDescriptorSP
ObjCLanguageRuntime::GetClassDescriptor(ValueObject &valobj) {
ClassDescriptorSP objc_class_sp;
// if we get an invalid VO (which might still happen when playing around with
// pointers returned by the expression parser, don't consider this a valid
// ObjC object)
if (valobj.GetCompilerType().IsValid()) {
addr_t isa_pointer = valobj.GetPointerValue();
if (isa_pointer != LLDB_INVALID_ADDRESS) {
ExecutionContext exe_ctx(valobj.GetExecutionContextRef());
Process *process = exe_ctx.GetProcessPtr();
if (process) {
Status error;
ObjCISA isa = process->ReadPointerFromMemory(isa_pointer, error);
if (isa != LLDB_INVALID_ADDRESS)
objc_class_sp = GetClassDescriptorFromISA(isa);
}
}
}
return objc_class_sp;
}
ObjCLanguageRuntime::ClassDescriptorSP
ObjCLanguageRuntime::GetNonKVOClassDescriptor(ValueObject &valobj) {
ObjCLanguageRuntime::ClassDescriptorSP objc_class_sp(
GetClassDescriptor(valobj));
if (objc_class_sp) {
if (!objc_class_sp->IsKVO())
return objc_class_sp;
ClassDescriptorSP non_kvo_objc_class_sp(objc_class_sp->GetSuperclass());
if (non_kvo_objc_class_sp && non_kvo_objc_class_sp->IsValid())
return non_kvo_objc_class_sp;
}
return ClassDescriptorSP();
}
ObjCLanguageRuntime::ClassDescriptorSP
ObjCLanguageRuntime::GetClassDescriptorFromISA(ObjCISA isa) {
if (isa) {
UpdateISAToDescriptorMap();
ObjCLanguageRuntime::ISAToDescriptorIterator pos =
m_isa_to_descriptor.find(isa);
if (pos != m_isa_to_descriptor.end())
return pos->second;
if (ABISP abi_sp = m_process->GetABI()) {
pos = m_isa_to_descriptor.find(abi_sp->FixCodeAddress(isa));
if (pos != m_isa_to_descriptor.end())
return pos->second;
}
}
return ClassDescriptorSP();
}
ObjCLanguageRuntime::ClassDescriptorSP
ObjCLanguageRuntime::GetNonKVOClassDescriptor(ObjCISA isa) {
if (isa) {
ClassDescriptorSP objc_class_sp = GetClassDescriptorFromISA(isa);
if (objc_class_sp && objc_class_sp->IsValid()) {
if (!objc_class_sp->IsKVO())
return objc_class_sp;
ClassDescriptorSP non_kvo_objc_class_sp(objc_class_sp->GetSuperclass());
if (non_kvo_objc_class_sp && non_kvo_objc_class_sp->IsValid())
return non_kvo_objc_class_sp;
}
}
return ClassDescriptorSP();
}
CompilerType
ObjCLanguageRuntime::EncodingToType::RealizeType(const char *name,
bool for_expression) {
if (m_scratch_ast_ctx_sp)
return RealizeType(*m_scratch_ast_ctx_sp, name, for_expression);
return CompilerType();
}
ObjCLanguageRuntime::EncodingToType::~EncodingToType() = default;
ObjCLanguageRuntime::EncodingToTypeSP ObjCLanguageRuntime::GetEncodingToType() {
return nullptr;
}
std::optional<uint64_t>
ObjCLanguageRuntime::GetTypeBitSize(const CompilerType &compiler_type) {
void *opaque_ptr = compiler_type.GetOpaqueQualType();
uint64_t cached_size = m_type_size_cache.Lookup(opaque_ptr);
if (cached_size > 0)
return cached_size;
ClassDescriptorSP class_descriptor_sp =
GetClassDescriptorFromClassName(compiler_type.GetTypeName());
if (!class_descriptor_sp)
return {};
int32_t max_offset = INT32_MIN;
uint64_t sizeof_max = 0;
bool found = false;
for (size_t idx = 0; idx < class_descriptor_sp->GetNumIVars(); idx++) {
const auto &ivar = class_descriptor_sp->GetIVarAtIndex(idx);
int32_t cur_offset = ivar.m_offset;
if (cur_offset > max_offset) {
max_offset = cur_offset;
sizeof_max = ivar.m_size;
found = true;
}
}
uint64_t size = 8 * (max_offset + sizeof_max);
if (found && size > 0) {
m_type_size_cache.Insert(opaque_ptr, size);
return size;
}
return {};
}
lldb::BreakpointPreconditionSP
ObjCLanguageRuntime::GetBreakpointExceptionPrecondition(LanguageType language,
bool throw_bp) {
if (language != eLanguageTypeObjC)
return lldb::BreakpointPreconditionSP();
if (!throw_bp)
return lldb::BreakpointPreconditionSP();
BreakpointPreconditionSP precondition_sp(
new ObjCLanguageRuntime::ObjCExceptionPrecondition());
return precondition_sp;
}
// Exception breakpoint Precondition class for ObjC:
void ObjCLanguageRuntime::ObjCExceptionPrecondition::AddClassName(
const char *class_name) {
m_class_names.insert(class_name);
}
ObjCLanguageRuntime::ObjCExceptionPrecondition::ObjCExceptionPrecondition() =
default;
bool ObjCLanguageRuntime::ObjCExceptionPrecondition::EvaluatePrecondition(
StoppointCallbackContext &context) {
return true;
}
void ObjCLanguageRuntime::ObjCExceptionPrecondition::GetDescription(
Stream &stream, lldb::DescriptionLevel level) {}
Status ObjCLanguageRuntime::ObjCExceptionPrecondition::ConfigurePrecondition(
Args &args) {
Status error;
if (args.GetArgumentCount() > 0)
error.SetErrorString(
"The ObjC Exception breakpoint doesn't support extra options.");
return error;
}
std::optional<CompilerType>
ObjCLanguageRuntime::GetRuntimeType(CompilerType base_type) {
CompilerType class_type;
bool is_pointer_type = false;
if (TypeSystemClang::IsObjCObjectPointerType(base_type, &class_type))
is_pointer_type = true;
else if (TypeSystemClang::IsObjCObjectOrInterfaceType(base_type))
class_type = base_type;
else
return std::nullopt;
if (!class_type)
return std::nullopt;
ConstString class_name(class_type.GetTypeName());
if (!class_name)
return std::nullopt;
TypeSP complete_objc_class_type_sp = LookupInCompleteClassCache(class_name);
if (!complete_objc_class_type_sp)
return std::nullopt;
CompilerType complete_class(
complete_objc_class_type_sp->GetFullCompilerType());
if (complete_class.GetCompleteType()) {
if (is_pointer_type)
return complete_class.GetPointerType();
else
return complete_class;
}
return std::nullopt;
}