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llvm-project/lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.cpp

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//===-- ItaniumABILanguageRuntime.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 "ItaniumABILanguageRuntime.h"
#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
#include "lldb/Breakpoint/BreakpointLocation.h"
#include "lldb/Core/Mangled.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectMemory.h"
#include "lldb/DataFormatters/FormattersHelpers.h"
#include "lldb/Expression/DiagnosticManager.h"
#include "lldb/Expression/FunctionCaller.h"
#include "lldb/Interpreter/CommandObject.h"
#include "lldb/Interpreter/CommandObjectMultiword.h"
#include "lldb/Interpreter/CommandReturnObject.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Symbol/SymbolFile.h"
#include "lldb/Symbol/TypeList.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/StopInfo.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Utility/ConstString.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/Scalar.h"
#include "lldb/Utility/Status.h"
#include <vector>
using namespace lldb;
using namespace lldb_private;
LLDB_PLUGIN(ItaniumABILanguageRuntime);
static const char *vtable_demangled_prefix = "vtable for ";
char ItaniumABILanguageRuntime::ID = 0;
bool ItaniumABILanguageRuntime::CouldHaveDynamicValue(ValueObject &in_value) {
const bool check_cxx = true;
const bool check_objc = false;
return in_value.GetCompilerType().IsPossibleDynamicType(nullptr, check_cxx,
check_objc);
}
TypeAndOrName ItaniumABILanguageRuntime::GetTypeInfoFromVTableAddress(
ValueObject &in_value, lldb::addr_t original_ptr,
lldb::addr_t vtable_load_addr) {
if (m_process && vtable_load_addr != LLDB_INVALID_ADDRESS) {
// Find the symbol that contains the "vtable_load_addr" address
Address vtable_addr;
Target &target = m_process->GetTarget();
if (!target.GetSectionLoadList().IsEmpty()) {
if (target.GetSectionLoadList().ResolveLoadAddress(vtable_load_addr,
vtable_addr)) {
// See if we have cached info for this type already
TypeAndOrName type_info = GetDynamicTypeInfo(vtable_addr);
if (type_info)
return type_info;
SymbolContext sc;
target.GetImages().ResolveSymbolContextForAddress(
vtable_addr, eSymbolContextSymbol, sc);
Symbol *symbol = sc.symbol;
if (symbol != nullptr) {
const char *name =
symbol->GetMangled().GetDemangledName().AsCString();
if (name && strstr(name, vtable_demangled_prefix) == name) {
Log *log(
lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_OBJECT));
LLDB_LOGF(log,
"0x%16.16" PRIx64
": static-type = '%s' has vtable symbol '%s'\n",
original_ptr, in_value.GetTypeName().GetCString(), name);
// We are a C++ class, that's good. Get the class name and look it
// up:
const char *class_name = name + strlen(vtable_demangled_prefix);
// We know the class name is absolute, so tell FindTypes that by
// prefixing it with the root namespace:
std::string lookup_name("::");
lookup_name.append(class_name);
type_info.SetName(class_name);
const bool exact_match = true;
TypeList class_types;
// First look in the module that the vtable symbol came from and
// look for a single exact match.
llvm::DenseSet<SymbolFile *> searched_symbol_files;
if (sc.module_sp)
sc.module_sp->FindTypes(ConstString(lookup_name), exact_match, 1,
searched_symbol_files, class_types);
// If we didn't find a symbol, then move on to the entire module
// list in the target and get as many unique matches as possible
if (class_types.Empty())
target.GetImages().FindTypes(nullptr, ConstString(lookup_name),
exact_match, UINT32_MAX,
searched_symbol_files, class_types);
lldb::TypeSP type_sp;
if (class_types.Empty()) {
LLDB_LOGF(log, "0x%16.16" PRIx64 ": is not dynamic\n",
original_ptr);
return TypeAndOrName();
}
if (class_types.GetSize() == 1) {
type_sp = class_types.GetTypeAtIndex(0);
if (type_sp) {
if (TypeSystemClang::IsCXXClassType(
type_sp->GetForwardCompilerType())) {
LLDB_LOGF(
log,
"0x%16.16" PRIx64
": static-type = '%s' has dynamic type: uid={0x%" PRIx64
"}, type-name='%s'\n",
original_ptr, in_value.GetTypeName().AsCString(),
type_sp->GetID(), type_sp->GetName().GetCString());
type_info.SetTypeSP(type_sp);
}
}
} else {
size_t i;
if (log) {
for (i = 0; i < class_types.GetSize(); i++) {
type_sp = class_types.GetTypeAtIndex(i);
if (type_sp) {
LLDB_LOGF(
log,
"0x%16.16" PRIx64
": static-type = '%s' has multiple matching dynamic "
"types: uid={0x%" PRIx64 "}, type-name='%s'\n",
original_ptr, in_value.GetTypeName().AsCString(),
type_sp->GetID(), type_sp->GetName().GetCString());
}
}
}
for (i = 0; i < class_types.GetSize(); i++) {
type_sp = class_types.GetTypeAtIndex(i);
if (type_sp) {
if (TypeSystemClang::IsCXXClassType(
type_sp->GetForwardCompilerType())) {
LLDB_LOGF(
log,
"0x%16.16" PRIx64 ": static-type = '%s' has multiple "
"matching dynamic types, picking "
"this one: uid={0x%" PRIx64 "}, type-name='%s'\n",
original_ptr, in_value.GetTypeName().AsCString(),
type_sp->GetID(), type_sp->GetName().GetCString());
type_info.SetTypeSP(type_sp);
}
}
}
if (log) {
LLDB_LOGF(log,
"0x%16.16" PRIx64
": static-type = '%s' has multiple matching dynamic "
"types, didn't find a C++ match\n",
original_ptr, in_value.GetTypeName().AsCString());
}
}
if (type_info)
SetDynamicTypeInfo(vtable_addr, type_info);
return type_info;
}
}
}
}
}
return TypeAndOrName();
}
bool ItaniumABILanguageRuntime::GetDynamicTypeAndAddress(
ValueObject &in_value, lldb::DynamicValueType use_dynamic,
TypeAndOrName &class_type_or_name, Address &dynamic_address,
Value::ValueType &value_type) {
// For Itanium, if the type has a vtable pointer in the object, it will be at
// offset 0 in the object. That will point to the "address point" within the
// vtable (not the beginning of the vtable.) We can then look up the symbol
// containing this "address point" and that symbol's name demangled will
// contain the full class name. The second pointer above the "address point"
// is the "offset_to_top". We'll use that to get the start of the value
// object which holds the dynamic type.
//
class_type_or_name.Clear();
value_type = Value::ValueType::eValueTypeScalar;
// Only a pointer or reference type can have a different dynamic and static
// type:
if (!CouldHaveDynamicValue(in_value))
return false;
// First job, pull out the address at 0 offset from the object.
AddressType address_type;
lldb::addr_t original_ptr = in_value.GetPointerValue(&address_type);
if (original_ptr == LLDB_INVALID_ADDRESS)
return false;
ExecutionContext exe_ctx(in_value.GetExecutionContextRef());
Process *process = exe_ctx.GetProcessPtr();
if (process == nullptr)
return false;
Status error;
const lldb::addr_t vtable_address_point =
process->ReadPointerFromMemory(original_ptr, error);
if (!error.Success() || vtable_address_point == LLDB_INVALID_ADDRESS)
return false;
class_type_or_name = GetTypeInfoFromVTableAddress(in_value, original_ptr,
vtable_address_point);
if (!class_type_or_name)
return false;
CompilerType type = class_type_or_name.GetCompilerType();
// There can only be one type with a given name, so we've just found
// duplicate definitions, and this one will do as well as any other. We
// don't consider something to have a dynamic type if it is the same as
// the static type. So compare against the value we were handed.
if (!type)
return true;
if (TypeSystemClang::AreTypesSame(in_value.GetCompilerType(), type)) {
// The dynamic type we found was the same type, so we don't have a
// dynamic type here...
return false;
}
// The offset_to_top is two pointers above the vtable pointer.
const uint32_t addr_byte_size = process->GetAddressByteSize();
const lldb::addr_t offset_to_top_location =
vtable_address_point - 2 * addr_byte_size;
// Watch for underflow, offset_to_top_location should be less than
// vtable_address_point
if (offset_to_top_location >= vtable_address_point)
return false;
const int64_t offset_to_top = process->ReadSignedIntegerFromMemory(
offset_to_top_location, addr_byte_size, INT64_MIN, error);
if (offset_to_top == INT64_MIN)
return false;
// So the dynamic type is a value that starts at offset_to_top above
// the original address.
lldb::addr_t dynamic_addr = original_ptr + offset_to_top;
if (!process->GetTarget().GetSectionLoadList().ResolveLoadAddress(
dynamic_addr, dynamic_address)) {
dynamic_address.SetRawAddress(dynamic_addr);
}
return true;
}
TypeAndOrName ItaniumABILanguageRuntime::FixUpDynamicType(
const TypeAndOrName &type_and_or_name, ValueObject &static_value) {
CompilerType static_type(static_value.GetCompilerType());
Flags static_type_flags(static_type.GetTypeInfo());
TypeAndOrName ret(type_and_or_name);
if (type_and_or_name.HasType()) {
// The type will always be the type of the dynamic object. If our parent's
// type was a pointer, then our type should be a pointer to the type of the
// dynamic object. If a reference, then the original type should be
// okay...
CompilerType orig_type = type_and_or_name.GetCompilerType();
CompilerType corrected_type = orig_type;
if (static_type_flags.AllSet(eTypeIsPointer))
corrected_type = orig_type.GetPointerType();
else if (static_type_flags.AllSet(eTypeIsReference))
corrected_type = orig_type.GetLValueReferenceType();
ret.SetCompilerType(corrected_type);
} else {
// If we are here we need to adjust our dynamic type name to include the
// correct & or * symbol
std::string corrected_name(type_and_or_name.GetName().GetCString());
if (static_type_flags.AllSet(eTypeIsPointer))
corrected_name.append(" *");
else if (static_type_flags.AllSet(eTypeIsReference))
corrected_name.append(" &");
// the parent type should be a correctly pointer'ed or referenc'ed type
ret.SetCompilerType(static_type);
ret.SetName(corrected_name.c_str());
}
return ret;
}
// Static Functions
LanguageRuntime *
ItaniumABILanguageRuntime::CreateInstance(Process *process,
lldb::LanguageType language) {
// FIXME: We have to check the process and make sure we actually know that
// this process supports
// the Itanium ABI.
if (language == eLanguageTypeC_plus_plus ||
language == eLanguageTypeC_plus_plus_03 ||
language == eLanguageTypeC_plus_plus_11 ||
language == eLanguageTypeC_plus_plus_14)
return new ItaniumABILanguageRuntime(process);
else
return nullptr;
}
class CommandObjectMultiwordItaniumABI_Demangle : public CommandObjectParsed {
public:
CommandObjectMultiwordItaniumABI_Demangle(CommandInterpreter &interpreter)
: CommandObjectParsed(interpreter, "demangle",
"Demangle a C++ mangled name.",
"language cplusplus demangle") {
CommandArgumentEntry arg;
CommandArgumentData index_arg;
// Define the first (and only) variant of this arg.
index_arg.arg_type = eArgTypeSymbol;
index_arg.arg_repetition = eArgRepeatPlus;
// There is only one variant this argument could be; put it into the
// argument entry.
arg.push_back(index_arg);
// Push the data for the first argument into the m_arguments vector.
m_arguments.push_back(arg);
}
~CommandObjectMultiwordItaniumABI_Demangle() override = default;
protected:
bool DoExecute(Args &command, CommandReturnObject &result) override {
bool demangled_any = false;
bool error_any = false;
for (auto &entry : command.entries()) {
if (entry.ref().empty())
continue;
// the actual Mangled class should be strict about this, but on the
// command line if you're copying mangled names out of 'nm' on Darwin,
// they will come out with an extra underscore - be willing to strip this
// on behalf of the user. This is the moral equivalent of the -_/-n
// options to c++filt
auto name = entry.ref();
if (name.startswith("__Z"))
name = name.drop_front();
Mangled mangled(name);
if (mangled.GuessLanguage() == lldb::eLanguageTypeC_plus_plus) {
ConstString demangled(mangled.GetDisplayDemangledName());
demangled_any = true;
result.AppendMessageWithFormat("%s ---> %s\n", entry.c_str(),
demangled.GetCString());
} else {
error_any = true;
result.AppendErrorWithFormat("%s is not a valid C++ mangled name\n",
entry.ref().str().c_str());
}
}
result.SetStatus(
error_any ? lldb::eReturnStatusFailed
: (demangled_any ? lldb::eReturnStatusSuccessFinishResult
: lldb::eReturnStatusSuccessFinishNoResult));
return result.Succeeded();
}
};
class CommandObjectMultiwordItaniumABI : public CommandObjectMultiword {
public:
CommandObjectMultiwordItaniumABI(CommandInterpreter &interpreter)
: CommandObjectMultiword(
interpreter, "cplusplus",
"Commands for operating on the C++ language runtime.",
"cplusplus <subcommand> [<subcommand-options>]") {
LoadSubCommand(
"demangle",
CommandObjectSP(
new CommandObjectMultiwordItaniumABI_Demangle(interpreter)));
}
~CommandObjectMultiwordItaniumABI() override = default;
};
void ItaniumABILanguageRuntime::Initialize() {
PluginManager::RegisterPlugin(
GetPluginNameStatic(), "Itanium ABI for the C++ language", CreateInstance,
[](CommandInterpreter &interpreter) -> lldb::CommandObjectSP {
return CommandObjectSP(
new CommandObjectMultiwordItaniumABI(interpreter));
});
}
void ItaniumABILanguageRuntime::Terminate() {
PluginManager::UnregisterPlugin(CreateInstance);
}
lldb_private::ConstString ItaniumABILanguageRuntime::GetPluginNameStatic() {
static ConstString g_name("itanium");
return g_name;
}
// PluginInterface protocol
lldb_private::ConstString ItaniumABILanguageRuntime::GetPluginName() {
return GetPluginNameStatic();
}
uint32_t ItaniumABILanguageRuntime::GetPluginVersion() { return 1; }
BreakpointResolverSP ItaniumABILanguageRuntime::CreateExceptionResolver(
Breakpoint *bkpt, bool catch_bp, bool throw_bp) {
return CreateExceptionResolver(bkpt, catch_bp, throw_bp, false);
}
BreakpointResolverSP ItaniumABILanguageRuntime::CreateExceptionResolver(
Breakpoint *bkpt, bool catch_bp, bool throw_bp, bool for_expressions) {
// One complication here is that most users DON'T want to stop at
// __cxa_allocate_expression, but until we can do anything better with
// predicting unwinding the expression parser does. So we have two forms of
// the exception breakpoints, one for expressions that leaves out
// __cxa_allocate_exception, and one that includes it. The
// SetExceptionBreakpoints does the latter, the CreateExceptionBreakpoint in
// the runtime the former.
static const char *g_catch_name = "__cxa_begin_catch";
static const char *g_throw_name1 = "__cxa_throw";
static const char *g_throw_name2 = "__cxa_rethrow";
static const char *g_exception_throw_name = "__cxa_allocate_exception";
std::vector<const char *> exception_names;
exception_names.reserve(4);
if (catch_bp)
exception_names.push_back(g_catch_name);
if (throw_bp) {
exception_names.push_back(g_throw_name1);
exception_names.push_back(g_throw_name2);
}
if (for_expressions)
exception_names.push_back(g_exception_throw_name);
BreakpointResolverSP resolver_sp(new BreakpointResolverName(
bkpt, exception_names.data(), exception_names.size(),
eFunctionNameTypeBase, eLanguageTypeUnknown, 0, eLazyBoolNo));
return resolver_sp;
}
lldb::SearchFilterSP ItaniumABILanguageRuntime::CreateExceptionSearchFilter() {
Target &target = m_process->GetTarget();
FileSpecList filter_modules;
if (target.GetArchitecture().GetTriple().getVendor() == llvm::Triple::Apple) {
// Limit the number of modules that are searched for these breakpoints for
// Apple binaries.
filter_modules.EmplaceBack("libc++abi.dylib");
filter_modules.EmplaceBack("libSystem.B.dylib");
}
return target.GetSearchFilterForModuleList(&filter_modules);
}
lldb::BreakpointSP ItaniumABILanguageRuntime::CreateExceptionBreakpoint(
bool catch_bp, bool throw_bp, bool for_expressions, bool is_internal) {
Target &target = m_process->GetTarget();
FileSpecList filter_modules;
BreakpointResolverSP exception_resolver_sp =
CreateExceptionResolver(nullptr, catch_bp, throw_bp, for_expressions);
SearchFilterSP filter_sp(CreateExceptionSearchFilter());
const bool hardware = false;
const bool resolve_indirect_functions = false;
return target.CreateBreakpoint(filter_sp, exception_resolver_sp, is_internal,
hardware, resolve_indirect_functions);
}
void ItaniumABILanguageRuntime::SetExceptionBreakpoints() {
if (!m_process)
return;
const bool catch_bp = false;
const bool throw_bp = true;
const bool is_internal = true;
const bool for_expressions = true;
// For the exception breakpoints set by the Expression parser, we'll be a
// little more aggressive and stop at exception allocation as well.
if (m_cxx_exception_bp_sp) {
m_cxx_exception_bp_sp->SetEnabled(true);
} else {
m_cxx_exception_bp_sp = CreateExceptionBreakpoint(
catch_bp, throw_bp, for_expressions, is_internal);
if (m_cxx_exception_bp_sp)
m_cxx_exception_bp_sp->SetBreakpointKind("c++ exception");
}
}
void ItaniumABILanguageRuntime::ClearExceptionBreakpoints() {
if (!m_process)
return;
if (m_cxx_exception_bp_sp) {
m_cxx_exception_bp_sp->SetEnabled(false);
}
}
bool ItaniumABILanguageRuntime::ExceptionBreakpointsAreSet() {
return m_cxx_exception_bp_sp && m_cxx_exception_bp_sp->IsEnabled();
}
bool ItaniumABILanguageRuntime::ExceptionBreakpointsExplainStop(
lldb::StopInfoSP stop_reason) {
if (!m_process)
return false;
if (!stop_reason || stop_reason->GetStopReason() != eStopReasonBreakpoint)
return false;
uint64_t break_site_id = stop_reason->GetValue();
return m_process->GetBreakpointSiteList().BreakpointSiteContainsBreakpoint(
break_site_id, m_cxx_exception_bp_sp->GetID());
}
ValueObjectSP ItaniumABILanguageRuntime::GetExceptionObjectForThread(
ThreadSP thread_sp) {
if (!thread_sp->SafeToCallFunctions())
return {};
TypeSystemClang *clang_ast_context =
TypeSystemClang::GetScratch(m_process->GetTarget());
if (!clang_ast_context)
return {};
CompilerType voidstar =
clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
DiagnosticManager diagnostics;
ExecutionContext exe_ctx;
EvaluateExpressionOptions options;
options.SetUnwindOnError(true);
options.SetIgnoreBreakpoints(true);
options.SetStopOthers(true);
options.SetTimeout(m_process->GetUtilityExpressionTimeout());
options.SetTryAllThreads(false);
thread_sp->CalculateExecutionContext(exe_ctx);
const ModuleList &modules = m_process->GetTarget().GetImages();
SymbolContextList contexts;
SymbolContext context;
modules.FindSymbolsWithNameAndType(
ConstString("__cxa_current_exception_type"), eSymbolTypeCode, contexts);
contexts.GetContextAtIndex(0, context);
if (!context.symbol) {
return {};
}
Address addr = context.symbol->GetAddress();
Status error;
FunctionCaller *function_caller =
m_process->GetTarget().GetFunctionCallerForLanguage(
eLanguageTypeC, voidstar, addr, ValueList(), "caller", error);
ExpressionResults func_call_ret;
Value results;
func_call_ret = function_caller->ExecuteFunction(exe_ctx, nullptr, options,
diagnostics, results);
if (func_call_ret != eExpressionCompleted || !error.Success()) {
return ValueObjectSP();
}
size_t ptr_size = m_process->GetAddressByteSize();
addr_t result_ptr = results.GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
addr_t exception_addr =
m_process->ReadPointerFromMemory(result_ptr - ptr_size, error);
if (!error.Success()) {
return ValueObjectSP();
}
lldb_private::formatters::InferiorSizedWord exception_isw(exception_addr,
*m_process);
ValueObjectSP exception = ValueObject::CreateValueObjectFromData(
"exception", exception_isw.GetAsData(m_process->GetByteOrder()), exe_ctx,
voidstar);
exception = exception->GetDynamicValue(eDynamicDontRunTarget);
return exception;
}
TypeAndOrName ItaniumABILanguageRuntime::GetDynamicTypeInfo(
const lldb_private::Address &vtable_addr) {
std::lock_guard<std::mutex> locker(m_dynamic_type_map_mutex);
DynamicTypeCache::const_iterator pos = m_dynamic_type_map.find(vtable_addr);
if (pos == m_dynamic_type_map.end())
return TypeAndOrName();
else
return pos->second;
}
void ItaniumABILanguageRuntime::SetDynamicTypeInfo(
const lldb_private::Address &vtable_addr, const TypeAndOrName &type_info) {
std::lock_guard<std::mutex> locker(m_dynamic_type_map_mutex);
m_dynamic_type_map[vtable_addr] = type_info;
}
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