forked from OSchip/llvm-project
410 lines
14 KiB
C++
410 lines
14 KiB
C++
//===-- ValueObjectVariable.cpp -------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "lldb/Core/ValueObjectVariable.h"
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#include "lldb/Core/Address.h"
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#include "lldb/Core/AddressRange.h"
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#include "lldb/Core/Module.h"
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#include "lldb/Core/Value.h"
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#include "lldb/Expression/DWARFExpression.h"
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#include "lldb/Symbol/Declaration.h"
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#include "lldb/Symbol/Function.h"
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#include "lldb/Symbol/ObjectFile.h"
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#include "lldb/Symbol/SymbolContext.h"
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#include "lldb/Symbol/SymbolContextScope.h"
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#include "lldb/Symbol/Type.h"
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#include "lldb/Symbol/Variable.h"
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#include "lldb/Target/ExecutionContext.h"
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#include "lldb/Target/Process.h"
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#include "lldb/Target/RegisterContext.h"
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#include "lldb/Target/Target.h"
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#include "lldb/Utility/DataExtractor.h"
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#include "lldb/Utility/RegisterValue.h"
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#include "lldb/Utility/Scalar.h"
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#include "lldb/Utility/Status.h"
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#include "lldb/lldb-private-enumerations.h"
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#include "lldb/lldb-types.h"
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#include "llvm/ADT/StringRef.h"
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#include <assert.h>
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#include <memory>
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namespace lldb_private {
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class ExecutionContextScope;
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}
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namespace lldb_private {
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class StackFrame;
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}
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namespace lldb_private {
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struct RegisterInfo;
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}
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using namespace lldb_private;
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lldb::ValueObjectSP
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ValueObjectVariable::Create(ExecutionContextScope *exe_scope,
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const lldb::VariableSP &var_sp) {
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auto manager_sp = ValueObjectManager::Create();
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return (new ValueObjectVariable(exe_scope, *manager_sp, var_sp))->GetSP();
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}
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ValueObjectVariable::ValueObjectVariable(ExecutionContextScope *exe_scope,
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ValueObjectManager &manager,
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const lldb::VariableSP &var_sp)
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: ValueObject(exe_scope, manager), m_variable_sp(var_sp) {
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// Do not attempt to construct one of these objects with no variable!
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assert(m_variable_sp.get() != nullptr);
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m_name = var_sp->GetName();
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}
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ValueObjectVariable::~ValueObjectVariable() {}
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CompilerType ValueObjectVariable::GetCompilerTypeImpl() {
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Type *var_type = m_variable_sp->GetType();
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if (var_type)
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return var_type->GetForwardCompilerType();
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return CompilerType();
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}
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ConstString ValueObjectVariable::GetTypeName() {
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Type *var_type = m_variable_sp->GetType();
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if (var_type)
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return var_type->GetName();
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return ConstString();
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}
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ConstString ValueObjectVariable::GetDisplayTypeName() {
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Type *var_type = m_variable_sp->GetType();
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if (var_type)
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return var_type->GetForwardCompilerType().GetDisplayTypeName();
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return ConstString();
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}
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ConstString ValueObjectVariable::GetQualifiedTypeName() {
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Type *var_type = m_variable_sp->GetType();
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if (var_type)
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return var_type->GetQualifiedName();
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return ConstString();
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}
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size_t ValueObjectVariable::CalculateNumChildren(uint32_t max) {
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CompilerType type(GetCompilerType());
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if (!type.IsValid())
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return 0;
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ExecutionContext exe_ctx(GetExecutionContextRef());
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const bool omit_empty_base_classes = true;
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auto child_count = type.GetNumChildren(omit_empty_base_classes, &exe_ctx);
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return child_count <= max ? child_count : max;
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}
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llvm::Optional<uint64_t> ValueObjectVariable::GetByteSize() {
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ExecutionContext exe_ctx(GetExecutionContextRef());
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CompilerType type(GetCompilerType());
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if (!type.IsValid())
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return {};
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return type.GetByteSize(exe_ctx.GetBestExecutionContextScope());
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}
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lldb::ValueType ValueObjectVariable::GetValueType() const {
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if (m_variable_sp)
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return m_variable_sp->GetScope();
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return lldb::eValueTypeInvalid;
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}
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bool ValueObjectVariable::UpdateValue() {
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SetValueIsValid(false);
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m_error.Clear();
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Variable *variable = m_variable_sp.get();
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DWARFExpression &expr = variable->LocationExpression();
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if (variable->GetLocationIsConstantValueData()) {
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// expr doesn't contain DWARF bytes, it contains the constant variable
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// value bytes themselves...
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if (expr.GetExpressionData(m_data))
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m_value.SetContext(Value::eContextTypeVariable, variable);
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else
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m_error.SetErrorString("empty constant data");
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// constant bytes can't be edited - sorry
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m_resolved_value.SetContext(Value::eContextTypeInvalid, nullptr);
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} else {
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lldb::addr_t loclist_base_load_addr = LLDB_INVALID_ADDRESS;
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ExecutionContext exe_ctx(GetExecutionContextRef());
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Target *target = exe_ctx.GetTargetPtr();
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if (target) {
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m_data.SetByteOrder(target->GetArchitecture().GetByteOrder());
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m_data.SetAddressByteSize(target->GetArchitecture().GetAddressByteSize());
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}
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if (expr.IsLocationList()) {
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SymbolContext sc;
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variable->CalculateSymbolContext(&sc);
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if (sc.function)
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loclist_base_load_addr =
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sc.function->GetAddressRange().GetBaseAddress().GetLoadAddress(
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target);
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}
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Value old_value(m_value);
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if (expr.Evaluate(&exe_ctx, nullptr, loclist_base_load_addr, nullptr,
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nullptr, m_value, &m_error)) {
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m_resolved_value = m_value;
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m_value.SetContext(Value::eContextTypeVariable, variable);
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CompilerType compiler_type = GetCompilerType();
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if (compiler_type.IsValid())
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m_value.SetCompilerType(compiler_type);
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Value::ValueType value_type = m_value.GetValueType();
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// The size of the buffer within m_value can be less than the size
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// prescribed by its type. E.g. this can happen when an expression only
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// partially describes an object (say, because it contains DW_OP_piece).
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//
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// In this case, grow m_value to the expected size. An alternative way to
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// handle this is to teach Value::GetValueAsData() and ValueObjectChild
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// not to read past the end of a host buffer, but this gets impractically
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// complicated as a Value's host buffer may be shared with a distant
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// ancestor or sibling in the ValueObject hierarchy.
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//
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// FIXME: When we grow m_value, we should represent the added bits as
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// undefined somehow instead of as 0's.
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if (value_type == Value::eValueTypeHostAddress &&
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compiler_type.IsValid()) {
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if (size_t value_buf_size = m_value.GetBuffer().GetByteSize()) {
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size_t value_size = m_value.GetValueByteSize(&m_error, &exe_ctx);
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if (m_error.Success() && value_buf_size < value_size)
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m_value.ResizeData(value_size);
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}
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}
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Process *process = exe_ctx.GetProcessPtr();
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const bool process_is_alive = process && process->IsAlive();
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switch (value_type) {
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case Value::eValueTypeVector:
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// fall through
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case Value::eValueTypeScalar:
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// The variable value is in the Scalar value inside the m_value. We can
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// point our m_data right to it.
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m_error =
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m_value.GetValueAsData(&exe_ctx, m_data, GetModule().get());
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break;
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case Value::eValueTypeFileAddress:
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case Value::eValueTypeLoadAddress:
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case Value::eValueTypeHostAddress:
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// The DWARF expression result was an address in the inferior process.
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// If this variable is an aggregate type, we just need the address as
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// the main value as all child variable objects will rely upon this
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// location and add an offset and then read their own values as needed.
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// If this variable is a simple type, we read all data for it into
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// m_data. Make sure this type has a value before we try and read it
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// If we have a file address, convert it to a load address if we can.
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if (value_type == Value::eValueTypeFileAddress && process_is_alive)
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m_value.ConvertToLoadAddress(GetModule().get(), target);
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if (!CanProvideValue()) {
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// this value object represents an aggregate type whose children have
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// values, but this object does not. So we say we are changed if our
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// location has changed.
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SetValueDidChange(value_type != old_value.GetValueType() ||
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m_value.GetScalar() != old_value.GetScalar());
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} else {
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// Copy the Value and set the context to use our Variable so it can
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// extract read its value into m_data appropriately
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Value value(m_value);
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value.SetContext(Value::eContextTypeVariable, variable);
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m_error =
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value.GetValueAsData(&exe_ctx, m_data, GetModule().get());
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SetValueDidChange(value_type != old_value.GetValueType() ||
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m_value.GetScalar() != old_value.GetScalar());
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}
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break;
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}
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SetValueIsValid(m_error.Success());
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} else {
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// could not find location, won't allow editing
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m_resolved_value.SetContext(Value::eContextTypeInvalid, nullptr);
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}
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}
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return m_error.Success();
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}
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void ValueObjectVariable::DoUpdateChildrenAddressType(ValueObject &valobj) {
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Value::ValueType value_type = valobj.GetValue().GetValueType();
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ExecutionContext exe_ctx(GetExecutionContextRef());
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Process *process = exe_ctx.GetProcessPtr();
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const bool process_is_alive = process && process->IsAlive();
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const uint32_t type_info = valobj.GetCompilerType().GetTypeInfo();
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const bool is_pointer_or_ref =
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(type_info & (lldb::eTypeIsPointer | lldb::eTypeIsReference)) != 0;
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switch (value_type) {
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case Value::eValueTypeFileAddress:
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// If this type is a pointer, then its children will be considered load
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// addresses if the pointer or reference is dereferenced, but only if
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// the process is alive.
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//
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// There could be global variables like in the following code:
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// struct LinkedListNode { Foo* foo; LinkedListNode* next; };
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// Foo g_foo1;
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// Foo g_foo2;
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// LinkedListNode g_second_node = { &g_foo2, NULL };
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// LinkedListNode g_first_node = { &g_foo1, &g_second_node };
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//
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// When we aren't running, we should be able to look at these variables
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// using the "target variable" command. Children of the "g_first_node"
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// always will be of the same address type as the parent. But children
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// of the "next" member of LinkedListNode will become load addresses if
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// we have a live process, or remain a file address if it was a file
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// address.
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if (process_is_alive && is_pointer_or_ref)
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valobj.SetAddressTypeOfChildren(eAddressTypeLoad);
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else
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valobj.SetAddressTypeOfChildren(eAddressTypeFile);
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break;
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case Value::eValueTypeHostAddress:
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// Same as above for load addresses, except children of pointer or refs
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// are always load addresses. Host addresses are used to store freeze
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// dried variables. If this type is a struct, the entire struct
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// contents will be copied into the heap of the
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// LLDB process, but we do not currently follow any pointers.
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if (is_pointer_or_ref)
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valobj.SetAddressTypeOfChildren(eAddressTypeLoad);
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else
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valobj.SetAddressTypeOfChildren(eAddressTypeHost);
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break;
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case Value::eValueTypeLoadAddress:
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case Value::eValueTypeScalar:
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case Value::eValueTypeVector:
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valobj.SetAddressTypeOfChildren(eAddressTypeLoad);
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break;
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}
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}
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bool ValueObjectVariable::IsInScope() {
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const ExecutionContextRef &exe_ctx_ref = GetExecutionContextRef();
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if (exe_ctx_ref.HasFrameRef()) {
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ExecutionContext exe_ctx(exe_ctx_ref);
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StackFrame *frame = exe_ctx.GetFramePtr();
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if (frame) {
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return m_variable_sp->IsInScope(frame);
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} else {
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// This ValueObject had a frame at one time, but now we can't locate it,
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// so return false since we probably aren't in scope.
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return false;
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}
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}
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// We have a variable that wasn't tied to a frame, which means it is a global
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// and is always in scope.
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return true;
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}
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lldb::ModuleSP ValueObjectVariable::GetModule() {
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if (m_variable_sp) {
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SymbolContextScope *sc_scope = m_variable_sp->GetSymbolContextScope();
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if (sc_scope) {
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return sc_scope->CalculateSymbolContextModule();
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}
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}
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return lldb::ModuleSP();
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}
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SymbolContextScope *ValueObjectVariable::GetSymbolContextScope() {
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if (m_variable_sp)
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return m_variable_sp->GetSymbolContextScope();
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return nullptr;
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}
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bool ValueObjectVariable::GetDeclaration(Declaration &decl) {
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if (m_variable_sp) {
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decl = m_variable_sp->GetDeclaration();
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return true;
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}
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return false;
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}
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const char *ValueObjectVariable::GetLocationAsCString() {
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if (m_resolved_value.GetContextType() == Value::eContextTypeRegisterInfo)
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return GetLocationAsCStringImpl(m_resolved_value, m_data);
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else
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return ValueObject::GetLocationAsCString();
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}
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bool ValueObjectVariable::SetValueFromCString(const char *value_str,
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Status &error) {
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if (!UpdateValueIfNeeded()) {
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error.SetErrorString("unable to update value before writing");
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return false;
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}
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if (m_resolved_value.GetContextType() == Value::eContextTypeRegisterInfo) {
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RegisterInfo *reg_info = m_resolved_value.GetRegisterInfo();
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ExecutionContext exe_ctx(GetExecutionContextRef());
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RegisterContext *reg_ctx = exe_ctx.GetRegisterContext();
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RegisterValue reg_value;
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if (!reg_info || !reg_ctx) {
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error.SetErrorString("unable to retrieve register info");
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return false;
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}
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error = reg_value.SetValueFromString(reg_info, llvm::StringRef(value_str));
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if (error.Fail())
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return false;
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if (reg_ctx->WriteRegister(reg_info, reg_value)) {
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SetNeedsUpdate();
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return true;
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} else {
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error.SetErrorString("unable to write back to register");
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return false;
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}
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} else
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return ValueObject::SetValueFromCString(value_str, error);
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}
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bool ValueObjectVariable::SetData(DataExtractor &data, Status &error) {
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if (!UpdateValueIfNeeded()) {
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error.SetErrorString("unable to update value before writing");
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return false;
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}
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if (m_resolved_value.GetContextType() == Value::eContextTypeRegisterInfo) {
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RegisterInfo *reg_info = m_resolved_value.GetRegisterInfo();
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ExecutionContext exe_ctx(GetExecutionContextRef());
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RegisterContext *reg_ctx = exe_ctx.GetRegisterContext();
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RegisterValue reg_value;
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if (!reg_info || !reg_ctx) {
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error.SetErrorString("unable to retrieve register info");
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return false;
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}
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error = reg_value.SetValueFromData(reg_info, data, 0, true);
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if (error.Fail())
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return false;
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if (reg_ctx->WriteRegister(reg_info, reg_value)) {
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SetNeedsUpdate();
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return true;
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} else {
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error.SetErrorString("unable to write back to register");
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return false;
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}
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} else
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return ValueObject::SetData(data, error);
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}
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