llvm-project/lldb/source/Core/Value.cpp

709 lines
23 KiB
C++

//===-- Value.cpp -----------------------------------------------*- 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
//
//===----------------------------------------------------------------------===//
#include "lldb/Core/Value.h"
#include "lldb/Core/Address.h"
#include "lldb/Core/Module.h"
#include "lldb/Symbol/CompilerType.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Symbol/Type.h"
#include "lldb/Symbol/Variable.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/ConstString.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/DataExtractor.h"
#include "lldb/Utility/Endian.h"
#include "lldb/Utility/FileSpec.h"
#include "lldb/Utility/State.h"
#include "lldb/Utility/Stream.h"
#include "lldb/lldb-defines.h"
#include "lldb/lldb-forward.h"
#include "lldb/lldb-types.h"
#include <memory>
#include <string>
#include <inttypes.h>
using namespace lldb;
using namespace lldb_private;
Value::Value()
: m_value(), m_vector(), m_compiler_type(), m_context(nullptr),
m_value_type(eValueTypeScalar), m_context_type(eContextTypeInvalid),
m_data_buffer() {}
Value::Value(const Scalar &scalar)
: m_value(scalar), m_vector(), m_compiler_type(), m_context(nullptr),
m_value_type(eValueTypeScalar), m_context_type(eContextTypeInvalid),
m_data_buffer() {}
Value::Value(const void *bytes, int len)
: m_value(), m_vector(), m_compiler_type(), m_context(nullptr),
m_value_type(eValueTypeHostAddress), m_context_type(eContextTypeInvalid),
m_data_buffer() {
SetBytes(bytes, len);
}
Value::Value(const Value &v)
: m_value(v.m_value), m_vector(v.m_vector),
m_compiler_type(v.m_compiler_type), m_context(v.m_context),
m_value_type(v.m_value_type), m_context_type(v.m_context_type),
m_data_buffer() {
const uintptr_t rhs_value =
(uintptr_t)v.m_value.ULongLong(LLDB_INVALID_ADDRESS);
if ((rhs_value != 0) &&
(rhs_value == (uintptr_t)v.m_data_buffer.GetBytes())) {
m_data_buffer.CopyData(v.m_data_buffer.GetBytes(),
v.m_data_buffer.GetByteSize());
m_value = (uintptr_t)m_data_buffer.GetBytes();
}
}
Value &Value::operator=(const Value &rhs) {
if (this != &rhs) {
m_value = rhs.m_value;
m_vector = rhs.m_vector;
m_compiler_type = rhs.m_compiler_type;
m_context = rhs.m_context;
m_value_type = rhs.m_value_type;
m_context_type = rhs.m_context_type;
const uintptr_t rhs_value =
(uintptr_t)rhs.m_value.ULongLong(LLDB_INVALID_ADDRESS);
if ((rhs_value != 0) &&
(rhs_value == (uintptr_t)rhs.m_data_buffer.GetBytes())) {
m_data_buffer.CopyData(rhs.m_data_buffer.GetBytes(),
rhs.m_data_buffer.GetByteSize());
m_value = (uintptr_t)m_data_buffer.GetBytes();
}
}
return *this;
}
void Value::SetBytes(const void *bytes, int len) {
m_value_type = eValueTypeHostAddress;
m_data_buffer.CopyData(bytes, len);
m_value = (uintptr_t)m_data_buffer.GetBytes();
}
void Value::AppendBytes(const void *bytes, int len) {
m_value_type = eValueTypeHostAddress;
m_data_buffer.AppendData(bytes, len);
m_value = (uintptr_t)m_data_buffer.GetBytes();
}
void Value::Dump(Stream *strm) {
m_value.GetValue(strm, true);
strm->Printf(", value_type = %s, context = %p, context_type = %s",
Value::GetValueTypeAsCString(m_value_type), m_context,
Value::GetContextTypeAsCString(m_context_type));
}
Value::ValueType Value::GetValueType() const { return m_value_type; }
AddressType Value::GetValueAddressType() const {
switch (m_value_type) {
default:
case eValueTypeScalar:
break;
case eValueTypeLoadAddress:
return eAddressTypeLoad;
case eValueTypeFileAddress:
return eAddressTypeFile;
case eValueTypeHostAddress:
return eAddressTypeHost;
}
return eAddressTypeInvalid;
}
RegisterInfo *Value::GetRegisterInfo() const {
if (m_context_type == eContextTypeRegisterInfo)
return static_cast<RegisterInfo *>(m_context);
return nullptr;
}
Type *Value::GetType() {
if (m_context_type == eContextTypeLLDBType)
return static_cast<Type *>(m_context);
return nullptr;
}
size_t Value::AppendDataToHostBuffer(const Value &rhs) {
if (this == &rhs)
return 0;
size_t curr_size = m_data_buffer.GetByteSize();
Status error;
switch (rhs.GetValueType()) {
case eValueTypeScalar: {
const size_t scalar_size = rhs.m_value.GetByteSize();
if (scalar_size > 0) {
const size_t new_size = curr_size + scalar_size;
if (ResizeData(new_size) == new_size) {
rhs.m_value.GetAsMemoryData(m_data_buffer.GetBytes() + curr_size,
scalar_size, endian::InlHostByteOrder(),
error);
return scalar_size;
}
}
} break;
case eValueTypeVector: {
const size_t vector_size = rhs.m_vector.length;
if (vector_size > 0) {
const size_t new_size = curr_size + vector_size;
if (ResizeData(new_size) == new_size) {
::memcpy(m_data_buffer.GetBytes() + curr_size, rhs.m_vector.bytes,
vector_size);
return vector_size;
}
}
} break;
case eValueTypeFileAddress:
case eValueTypeLoadAddress:
case eValueTypeHostAddress: {
const uint8_t *src = rhs.GetBuffer().GetBytes();
const size_t src_len = rhs.GetBuffer().GetByteSize();
if (src && src_len > 0) {
const size_t new_size = curr_size + src_len;
if (ResizeData(new_size) == new_size) {
::memcpy(m_data_buffer.GetBytes() + curr_size, src, src_len);
return src_len;
}
}
} break;
}
return 0;
}
size_t Value::ResizeData(size_t len) {
m_value_type = eValueTypeHostAddress;
m_data_buffer.SetByteSize(len);
m_value = (uintptr_t)m_data_buffer.GetBytes();
return m_data_buffer.GetByteSize();
}
bool Value::ValueOf(ExecutionContext *exe_ctx) {
switch (m_context_type) {
case eContextTypeInvalid:
case eContextTypeRegisterInfo: // RegisterInfo *
case eContextTypeLLDBType: // Type *
break;
case eContextTypeVariable: // Variable *
ResolveValue(exe_ctx);
return true;
}
return false;
}
uint64_t Value::GetValueByteSize(Status *error_ptr, ExecutionContext *exe_ctx) {
switch (m_context_type) {
case eContextTypeRegisterInfo: // RegisterInfo *
if (GetRegisterInfo()) {
if (error_ptr)
error_ptr->Clear();
return GetRegisterInfo()->byte_size;
}
break;
case eContextTypeInvalid:
case eContextTypeLLDBType: // Type *
case eContextTypeVariable: // Variable *
{
auto *scope = exe_ctx ? exe_ctx->GetBestExecutionContextScope() : nullptr;
if (llvm::Optional<uint64_t> size = GetCompilerType().GetByteSize(scope)) {
if (error_ptr)
error_ptr->Clear();
return *size;
}
break;
}
}
if (error_ptr && error_ptr->Success())
error_ptr->SetErrorString("Unable to determine byte size.");
return 0;
}
const CompilerType &Value::GetCompilerType() {
if (!m_compiler_type.IsValid()) {
switch (m_context_type) {
case eContextTypeInvalid:
break;
case eContextTypeRegisterInfo:
break; // TODO: Eventually convert into a compiler type?
case eContextTypeLLDBType: {
Type *lldb_type = GetType();
if (lldb_type)
m_compiler_type = lldb_type->GetForwardCompilerType();
} break;
case eContextTypeVariable: {
Variable *variable = GetVariable();
if (variable) {
Type *variable_type = variable->GetType();
if (variable_type)
m_compiler_type = variable_type->GetForwardCompilerType();
}
} break;
}
}
return m_compiler_type;
}
void Value::SetCompilerType(const CompilerType &compiler_type) {
m_compiler_type = compiler_type;
}
lldb::Format Value::GetValueDefaultFormat() {
switch (m_context_type) {
case eContextTypeRegisterInfo:
if (GetRegisterInfo())
return GetRegisterInfo()->format;
break;
case eContextTypeInvalid:
case eContextTypeLLDBType:
case eContextTypeVariable: {
const CompilerType &ast_type = GetCompilerType();
if (ast_type.IsValid())
return ast_type.GetFormat();
} break;
}
// Return a good default in case we can't figure anything out
return eFormatHex;
}
bool Value::GetData(DataExtractor &data) {
switch (m_value_type) {
default:
break;
case eValueTypeScalar:
if (m_value.GetData(data))
return true;
break;
case eValueTypeLoadAddress:
case eValueTypeFileAddress:
case eValueTypeHostAddress:
if (m_data_buffer.GetByteSize()) {
data.SetData(m_data_buffer.GetBytes(), m_data_buffer.GetByteSize(),
data.GetByteOrder());
return true;
}
break;
}
return false;
}
Status Value::GetValueAsData(ExecutionContext *exe_ctx, DataExtractor &data,
uint32_t data_offset, Module *module) {
data.Clear();
Status error;
lldb::addr_t address = LLDB_INVALID_ADDRESS;
AddressType address_type = eAddressTypeFile;
Address file_so_addr;
const CompilerType &ast_type = GetCompilerType();
switch (m_value_type) {
case eValueTypeVector:
if (ast_type.IsValid())
data.SetAddressByteSize(ast_type.GetPointerByteSize());
else
data.SetAddressByteSize(sizeof(void *));
data.SetData(m_vector.bytes, m_vector.length, m_vector.byte_order);
break;
case eValueTypeScalar: {
data.SetByteOrder(endian::InlHostByteOrder());
if (ast_type.IsValid())
data.SetAddressByteSize(ast_type.GetPointerByteSize());
else
data.SetAddressByteSize(sizeof(void *));
uint32_t limit_byte_size = UINT32_MAX;
if (llvm::Optional<uint64_t> size = ast_type.GetByteSize(
exe_ctx ? exe_ctx->GetBestExecutionContextScope() : nullptr))
limit_byte_size = *size;
if (limit_byte_size <= m_value.GetByteSize()) {
if (m_value.GetData(data, limit_byte_size))
return error; // Success;
}
error.SetErrorStringWithFormat("extracting data from value failed");
break;
}
case eValueTypeLoadAddress:
if (exe_ctx == nullptr) {
error.SetErrorString("can't read load address (no execution context)");
} else {
Process *process = exe_ctx->GetProcessPtr();
if (process == nullptr || !process->IsAlive()) {
Target *target = exe_ctx->GetTargetPtr();
if (target) {
// Allow expressions to run and evaluate things when the target has
// memory sections loaded. This allows you to use "target modules
// load" to load your executable and any shared libraries, then
// execute commands where you can look at types in data sections.
const SectionLoadList &target_sections = target->GetSectionLoadList();
if (!target_sections.IsEmpty()) {
address = m_value.ULongLong(LLDB_INVALID_ADDRESS);
if (target_sections.ResolveLoadAddress(address, file_so_addr)) {
address_type = eAddressTypeLoad;
data.SetByteOrder(target->GetArchitecture().GetByteOrder());
data.SetAddressByteSize(
target->GetArchitecture().GetAddressByteSize());
} else
address = LLDB_INVALID_ADDRESS;
}
} else {
error.SetErrorString("can't read load address (invalid process)");
}
} else {
address = m_value.ULongLong(LLDB_INVALID_ADDRESS);
address_type = eAddressTypeLoad;
data.SetByteOrder(
process->GetTarget().GetArchitecture().GetByteOrder());
data.SetAddressByteSize(
process->GetTarget().GetArchitecture().GetAddressByteSize());
}
}
break;
case eValueTypeFileAddress:
if (exe_ctx == nullptr) {
error.SetErrorString("can't read file address (no execution context)");
} else if (exe_ctx->GetTargetPtr() == nullptr) {
error.SetErrorString("can't read file address (invalid target)");
} else {
address = m_value.ULongLong(LLDB_INVALID_ADDRESS);
if (address == LLDB_INVALID_ADDRESS) {
error.SetErrorString("invalid file address");
} else {
if (module == nullptr) {
// The only thing we can currently lock down to a module so that we
// can resolve a file address, is a variable.
Variable *variable = GetVariable();
if (variable) {
SymbolContext var_sc;
variable->CalculateSymbolContext(&var_sc);
module = var_sc.module_sp.get();
}
}
if (module) {
bool resolved = false;
ObjectFile *objfile = module->GetObjectFile();
if (objfile) {
Address so_addr(address, objfile->GetSectionList());
addr_t load_address =
so_addr.GetLoadAddress(exe_ctx->GetTargetPtr());
bool process_launched_and_stopped =
exe_ctx->GetProcessPtr()
? StateIsStoppedState(exe_ctx->GetProcessPtr()->GetState(),
true /* must_exist */)
: false;
// Don't use the load address if the process has exited.
if (load_address != LLDB_INVALID_ADDRESS &&
process_launched_and_stopped) {
resolved = true;
address = load_address;
address_type = eAddressTypeLoad;
data.SetByteOrder(
exe_ctx->GetTargetRef().GetArchitecture().GetByteOrder());
data.SetAddressByteSize(exe_ctx->GetTargetRef()
.GetArchitecture()
.GetAddressByteSize());
} else {
if (so_addr.IsSectionOffset()) {
resolved = true;
file_so_addr = so_addr;
data.SetByteOrder(objfile->GetByteOrder());
data.SetAddressByteSize(objfile->GetAddressByteSize());
}
}
}
if (!resolved) {
Variable *variable = GetVariable();
if (module) {
if (variable)
error.SetErrorStringWithFormat(
"unable to resolve the module for file address 0x%" PRIx64
" for variable '%s' in %s",
address, variable->GetName().AsCString(""),
module->GetFileSpec().GetPath().c_str());
else
error.SetErrorStringWithFormat(
"unable to resolve the module for file address 0x%" PRIx64
" in %s",
address, module->GetFileSpec().GetPath().c_str());
} else {
if (variable)
error.SetErrorStringWithFormat(
"unable to resolve the module for file address 0x%" PRIx64
" for variable '%s'",
address, variable->GetName().AsCString(""));
else
error.SetErrorStringWithFormat(
"unable to resolve the module for file address 0x%" PRIx64,
address);
}
}
} else {
// Can't convert a file address to anything valid without more
// context (which Module it came from)
error.SetErrorString(
"can't read memory from file address without more context");
}
}
}
break;
case eValueTypeHostAddress:
address = m_value.ULongLong(LLDB_INVALID_ADDRESS);
address_type = eAddressTypeHost;
if (exe_ctx) {
Target *target = exe_ctx->GetTargetPtr();
if (target) {
data.SetByteOrder(target->GetArchitecture().GetByteOrder());
data.SetAddressByteSize(target->GetArchitecture().GetAddressByteSize());
break;
}
}
// fallback to host settings
data.SetByteOrder(endian::InlHostByteOrder());
data.SetAddressByteSize(sizeof(void *));
break;
}
// Bail if we encountered any errors
if (error.Fail())
return error;
if (address == LLDB_INVALID_ADDRESS) {
error.SetErrorStringWithFormat("invalid %s address",
address_type == eAddressTypeHost ? "host"
: "load");
return error;
}
// If we got here, we need to read the value from memory
size_t byte_size = GetValueByteSize(&error, exe_ctx);
// Bail if we encountered any errors getting the byte size
if (error.Fail())
return error;
// No memory to read for zero-sized types.
if (byte_size == 0)
return error;
// Make sure we have enough room within "data", and if we don't make
// something large enough that does
if (!data.ValidOffsetForDataOfSize(data_offset, byte_size)) {
auto data_sp =
std::make_shared<DataBufferHeap>(data_offset + byte_size, '\0');
data.SetData(data_sp);
}
uint8_t *dst = const_cast<uint8_t *>(data.PeekData(data_offset, byte_size));
if (dst != nullptr) {
if (address_type == eAddressTypeHost) {
// The address is an address in this process, so just copy it.
if (address == 0) {
error.SetErrorStringWithFormat(
"trying to read from host address of 0.");
return error;
}
memcpy(dst, reinterpret_cast<uint8_t *>(address), byte_size);
} else if ((address_type == eAddressTypeLoad) ||
(address_type == eAddressTypeFile)) {
if (file_so_addr.IsValid()) {
// We have a file address that we were able to translate into a section
// offset address so we might be able to read this from the object
// files if we don't have a live process. Lets always try and read from
// the process if we have one though since we want to read the actual
// value by setting "prefer_file_cache" to false.
const bool prefer_file_cache = false;
if (exe_ctx->GetTargetRef().ReadMemory(file_so_addr, prefer_file_cache,
dst, byte_size,
error) != byte_size) {
error.SetErrorStringWithFormat(
"read memory from 0x%" PRIx64 " failed", (uint64_t)address);
}
} else {
// The execution context might have a NULL process, but it might have a
// valid process in the exe_ctx->target, so use the
// ExecutionContext::GetProcess accessor to ensure we get the process
// if there is one.
Process *process = exe_ctx->GetProcessPtr();
if (process) {
const size_t bytes_read =
process->ReadMemory(address, dst, byte_size, error);
if (bytes_read != byte_size)
error.SetErrorStringWithFormat(
"read memory from 0x%" PRIx64 " failed (%u of %u bytes read)",
(uint64_t)address, (uint32_t)bytes_read, (uint32_t)byte_size);
} else {
error.SetErrorStringWithFormat("read memory from 0x%" PRIx64
" failed (invalid process)",
(uint64_t)address);
}
}
} else {
error.SetErrorStringWithFormat("unsupported AddressType value (%i)",
address_type);
}
} else {
error.SetErrorStringWithFormat("out of memory");
}
return error;
}
Scalar &Value::ResolveValue(ExecutionContext *exe_ctx) {
const CompilerType &compiler_type = GetCompilerType();
if (compiler_type.IsValid()) {
switch (m_value_type) {
case eValueTypeScalar: // raw scalar value
break;
default:
case eValueTypeFileAddress:
case eValueTypeLoadAddress: // load address value
case eValueTypeHostAddress: // host address value (for memory in the process
// that is using liblldb)
{
DataExtractor data;
lldb::addr_t addr = m_value.ULongLong(LLDB_INVALID_ADDRESS);
Status error(GetValueAsData(exe_ctx, data, 0, nullptr));
if (error.Success()) {
Scalar scalar;
if (compiler_type.GetValueAsScalar(data, 0, data.GetByteSize(),
scalar)) {
m_value = scalar;
m_value_type = eValueTypeScalar;
} else {
if ((uintptr_t)addr != (uintptr_t)m_data_buffer.GetBytes()) {
m_value.Clear();
m_value_type = eValueTypeScalar;
}
}
} else {
if ((uintptr_t)addr != (uintptr_t)m_data_buffer.GetBytes()) {
m_value.Clear();
m_value_type = eValueTypeScalar;
}
}
} break;
}
}
return m_value;
}
Variable *Value::GetVariable() {
if (m_context_type == eContextTypeVariable)
return static_cast<Variable *>(m_context);
return nullptr;
}
void Value::Clear() {
m_value.Clear();
m_vector.Clear();
m_compiler_type.Clear();
m_value_type = eValueTypeScalar;
m_context = nullptr;
m_context_type = eContextTypeInvalid;
m_data_buffer.Clear();
}
const char *Value::GetValueTypeAsCString(ValueType value_type) {
switch (value_type) {
case eValueTypeScalar:
return "scalar";
case eValueTypeVector:
return "vector";
case eValueTypeFileAddress:
return "file address";
case eValueTypeLoadAddress:
return "load address";
case eValueTypeHostAddress:
return "host address";
};
return "???";
}
const char *Value::GetContextTypeAsCString(ContextType context_type) {
switch (context_type) {
case eContextTypeInvalid:
return "invalid";
case eContextTypeRegisterInfo:
return "RegisterInfo *";
case eContextTypeLLDBType:
return "Type *";
case eContextTypeVariable:
return "Variable *";
};
return "???";
}
void Value::ConvertToLoadAddress(Module *module, Target *target) {
if (!module || !target || (GetValueType() != eValueTypeFileAddress))
return;
lldb::addr_t file_addr = GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
if (file_addr == LLDB_INVALID_ADDRESS)
return;
Address so_addr;
if (!module->ResolveFileAddress(file_addr, so_addr))
return;
lldb::addr_t load_addr = so_addr.GetLoadAddress(target);
if (load_addr == LLDB_INVALID_ADDRESS)
return;
SetValueType(Value::eValueTypeLoadAddress);
GetScalar() = load_addr;
}
ValueList::ValueList(const ValueList &rhs) { m_values = rhs.m_values; }
const ValueList &ValueList::operator=(const ValueList &rhs) {
m_values = rhs.m_values;
return *this;
}
void ValueList::PushValue(const Value &value) { m_values.push_back(value); }
size_t ValueList::GetSize() { return m_values.size(); }
Value *ValueList::GetValueAtIndex(size_t idx) {
if (idx < GetSize()) {
return &(m_values[idx]);
} else
return nullptr;
}
void ValueList::Clear() { m_values.clear(); }