97ca9ca180
Displaying large packed bitfields did not work if one was accessing them
through a pointer, and he used the "->" notation ("[0]." notation is
fine). The reason for that is that implicit dereference in -> is plumbed
all the way down to ValueObjectChild::UpdateValue, where the process of
fetching the child value was forked for this flag. The bitfield
"sliding" code was implemented only for the branch which did not require
dereferencing.
This patch restructures the function to avoid this mistake. Processing
now happens in two stages.
- first the parent is dereferenced (if needed)
- then the child value is computed (this step includes sliding and is
common for both branches)
Differential Revision: https://reviews.llvm.org/D89236
228 lines
8.3 KiB
C++
228 lines
8.3 KiB
C++
//===-- ValueObjectChild.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/ValueObjectChild.h"
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#include "lldb/Core/Value.h"
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#include "lldb/Symbol/CompilerType.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/Utility/Flags.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-forward.h"
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#include <functional>
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#include <memory>
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#include <vector>
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#include <stdio.h>
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#include <string.h>
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using namespace lldb_private;
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ValueObjectChild::ValueObjectChild(
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ValueObject &parent, const CompilerType &compiler_type,
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ConstString name, uint64_t byte_size, int32_t byte_offset,
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uint32_t bitfield_bit_size, uint32_t bitfield_bit_offset,
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bool is_base_class, bool is_deref_of_parent,
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AddressType child_ptr_or_ref_addr_type, uint64_t language_flags)
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: ValueObject(parent), m_compiler_type(compiler_type),
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m_byte_size(byte_size), m_byte_offset(byte_offset),
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m_bitfield_bit_size(bitfield_bit_size),
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m_bitfield_bit_offset(bitfield_bit_offset),
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m_is_base_class(is_base_class), m_is_deref_of_parent(is_deref_of_parent),
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m_can_update_with_invalid_exe_ctx() {
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m_name = name;
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SetAddressTypeOfChildren(child_ptr_or_ref_addr_type);
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SetLanguageFlags(language_flags);
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}
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ValueObjectChild::~ValueObjectChild() {}
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lldb::ValueType ValueObjectChild::GetValueType() const {
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return m_parent->GetValueType();
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}
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size_t ValueObjectChild::CalculateNumChildren(uint32_t max) {
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ExecutionContext exe_ctx(GetExecutionContextRef());
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auto children_count = GetCompilerType().GetNumChildren(true, &exe_ctx);
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return children_count <= max ? children_count : max;
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}
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static void AdjustForBitfieldness(ConstString &name,
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uint8_t bitfield_bit_size) {
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if (name && bitfield_bit_size)
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name.SetString(llvm::formatv("{0}:{1}", name, bitfield_bit_size).str());
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}
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ConstString ValueObjectChild::GetTypeName() {
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if (m_type_name.IsEmpty()) {
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m_type_name = GetCompilerType().GetTypeName();
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AdjustForBitfieldness(m_type_name, m_bitfield_bit_size);
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}
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return m_type_name;
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}
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ConstString ValueObjectChild::GetQualifiedTypeName() {
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ConstString qualified_name = GetCompilerType().GetTypeName();
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AdjustForBitfieldness(qualified_name, m_bitfield_bit_size);
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return qualified_name;
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}
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ConstString ValueObjectChild::GetDisplayTypeName() {
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ConstString display_name = GetCompilerType().GetDisplayTypeName();
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AdjustForBitfieldness(display_name, m_bitfield_bit_size);
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return display_name;
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}
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LazyBool ValueObjectChild::CanUpdateWithInvalidExecutionContext() {
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if (m_can_update_with_invalid_exe_ctx.hasValue())
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return m_can_update_with_invalid_exe_ctx.getValue();
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if (m_parent) {
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ValueObject *opinionated_parent =
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m_parent->FollowParentChain([](ValueObject *valobj) -> bool {
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return (valobj->CanUpdateWithInvalidExecutionContext() ==
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eLazyBoolCalculate);
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});
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if (opinionated_parent)
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return (m_can_update_with_invalid_exe_ctx =
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opinionated_parent->CanUpdateWithInvalidExecutionContext())
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.getValue();
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}
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return (m_can_update_with_invalid_exe_ctx =
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this->ValueObject::CanUpdateWithInvalidExecutionContext())
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.getValue();
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}
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bool ValueObjectChild::UpdateValue() {
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m_error.Clear();
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SetValueIsValid(false);
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ValueObject *parent = m_parent;
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if (parent) {
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if (parent->UpdateValueIfNeeded(false)) {
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m_value.SetCompilerType(GetCompilerType());
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CompilerType parent_type(parent->GetCompilerType());
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// Copy the parent scalar value and the scalar value type
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m_value.GetScalar() = parent->GetValue().GetScalar();
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m_value.SetValueType(parent->GetValue().GetValueType());
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Flags parent_type_flags(parent_type.GetTypeInfo());
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const bool is_instance_ptr_base =
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((m_is_base_class) &&
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(parent_type_flags.AnySet(lldb::eTypeInstanceIsPointer)));
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if (parent->GetCompilerType().ShouldTreatScalarValueAsAddress()) {
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m_value.GetScalar() = parent->GetPointerValue();
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switch (parent->GetAddressTypeOfChildren()) {
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case eAddressTypeFile: {
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lldb::ProcessSP process_sp(GetProcessSP());
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if (process_sp && process_sp->IsAlive())
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m_value.SetValueType(Value::eValueTypeLoadAddress);
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else
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m_value.SetValueType(Value::eValueTypeFileAddress);
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} break;
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case eAddressTypeLoad:
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m_value.SetValueType(is_instance_ptr_base
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? Value::eValueTypeScalar
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: Value::eValueTypeLoadAddress);
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break;
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case eAddressTypeHost:
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m_value.SetValueType(Value::eValueTypeHostAddress);
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break;
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case eAddressTypeInvalid:
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// TODO: does this make sense?
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m_value.SetValueType(Value::eValueTypeScalar);
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break;
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}
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}
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switch (m_value.GetValueType()) {
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case Value::eValueTypeLoadAddress:
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case Value::eValueTypeFileAddress:
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case Value::eValueTypeHostAddress: {
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lldb::addr_t addr = m_value.GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
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if (addr == LLDB_INVALID_ADDRESS) {
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m_error.SetErrorString("parent address is invalid.");
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} else if (addr == 0) {
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m_error.SetErrorString("parent is NULL");
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} else {
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// If a bitfield doesn't fit into the child_byte_size'd window at
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// child_byte_offset, move the window forward until it fits. The
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// problem here is that Value has no notion of bitfields and thus the
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// Value's DataExtractor is sized like the bitfields CompilerType; a
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// sequence of bitfields, however, can be larger than their underlying
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// type.
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if (m_bitfield_bit_offset) {
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const bool thread_and_frame_only_if_stopped = true;
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ExecutionContext exe_ctx(GetExecutionContextRef().Lock(
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thread_and_frame_only_if_stopped));
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if (auto type_bit_size = GetCompilerType().GetBitSize(
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exe_ctx.GetBestExecutionContextScope())) {
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uint64_t bitfield_end =
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m_bitfield_bit_size + m_bitfield_bit_offset;
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if (bitfield_end > *type_bit_size) {
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uint64_t overhang_bytes =
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(bitfield_end - *type_bit_size + 7) / 8;
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m_byte_offset += overhang_bytes;
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m_bitfield_bit_offset -= overhang_bytes * 8;
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}
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}
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}
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// Set this object's scalar value to the address of its value by
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// adding its byte offset to the parent address
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m_value.GetScalar() += m_byte_offset;
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}
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} break;
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case Value::eValueTypeScalar:
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// try to extract the child value from the parent's scalar value
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{
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Scalar scalar(m_value.GetScalar());
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scalar.ExtractBitfield(8 * m_byte_size, 8 * m_byte_offset);
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m_value.GetScalar() = scalar;
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}
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break;
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default:
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m_error.SetErrorString("parent has invalid value.");
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break;
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}
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if (m_error.Success()) {
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const bool thread_and_frame_only_if_stopped = true;
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ExecutionContext exe_ctx(
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GetExecutionContextRef().Lock(thread_and_frame_only_if_stopped));
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if (GetCompilerType().GetTypeInfo() & lldb::eTypeHasValue) {
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Value &value = is_instance_ptr_base ? m_parent->GetValue() : m_value;
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m_error =
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value.GetValueAsData(&exe_ctx, m_data, GetModule().get());
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} else {
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m_error.Clear(); // No value so nothing to read...
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}
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}
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} else {
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m_error.SetErrorStringWithFormat("parent failed to evaluate: %s",
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parent->GetError().AsCString());
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}
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} else {
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m_error.SetErrorString("ValueObjectChild has a NULL parent ValueObject.");
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}
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return m_error.Success();
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}
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bool ValueObjectChild::IsInScope() {
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ValueObject *root(GetRoot());
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if (root)
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return root->IsInScope();
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return false;
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}
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