3b9269882e
Summary: When dwo support was introduced, it used a trick where debug info entries were referenced by the offset of the compile unit in the main file, but the die offset was relative to the dwo file. Although there was some elegance to it, this representation was starting to reach its breaking point: - the fact that the skeleton compile unit owned the DWO file meant that it was impossible (or at least hard and unintuitive) to support DWO files containing more than one compile unit. These kinds of files are produced by LTO for example. - it made it impossible to reference any DIEs in the skeleton compile unit (although the skeleton units are generally empty, clang still puts some info into them with -fsplit-dwarf-inlining). - (current motivation) it made it very hard to support type units placed in DWO files, as type units don't have any skeleton units which could be referenced in the main file This patch addresses this problem by introducing an new "dwo_num" field to the DIERef class, whose purpose is to identify the dwo file. It's kind of similar to the dwo_id field in DWARF5 unit headers, but while this is a 64bit hash whose main purpose is to catch file mismatches, this is just a smaller integer used to indentify a loaded dwo file. Currently, this is based on the index of the skeleton compile unit which owns the dwo file, but it is intended to be eventually independent of that (to support the LTO use case). Simultaneously the cu_offset is dropped to conserve space, as it is no longer necessary. This means we can remove the "BaseObjectOffset" field from the DWARFUnit class. It also means we can remove some of the workarounds put in place to support the skeleton-unit+dwo-die combo. More work is needed to remove all of them, which is out of scope of this patch. Reviewers: JDevlieghere, clayborg, aprantl Subscribers: mehdi_amini, dexonsmith, arphaman, lldb-commits Differential Revision: https://reviews.llvm.org/D63428 llvm-svn: 364009
150 lines
3.8 KiB
C++
150 lines
3.8 KiB
C++
//===-- DWARFBaseDIE.cpp ---------------------------------------*- C++ -*-===//
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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 "DWARFBaseDIE.h"
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#include "DWARFUnit.h"
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#include "DWARFDebugInfoEntry.h"
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#include "SymbolFileDWARF.h"
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#include "lldb/Core/Module.h"
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#include "lldb/Symbol/ObjectFile.h"
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using namespace lldb_private;
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llvm::Optional<DIERef> DWARFBaseDIE::GetDIERef() const {
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if (!IsValid())
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return llvm::None;
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return DIERef(m_cu->GetSymbolFileDWARF().GetDwoNum(), m_cu->GetDebugSection(),
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m_die->GetOffset());
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}
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dw_tag_t DWARFBaseDIE::Tag() const {
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if (m_die)
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return m_die->Tag();
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else
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return 0;
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}
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const char *DWARFBaseDIE::GetTagAsCString() const {
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return lldb_private::DW_TAG_value_to_name(Tag());
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}
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const char *DWARFBaseDIE::GetAttributeValueAsString(const dw_attr_t attr,
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const char *fail_value) const {
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if (IsValid())
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return m_die->GetAttributeValueAsString(GetCU(), attr, fail_value);
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else
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return fail_value;
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}
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uint64_t DWARFBaseDIE::GetAttributeValueAsUnsigned(const dw_attr_t attr,
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uint64_t fail_value) const {
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if (IsValid())
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return m_die->GetAttributeValueAsUnsigned(GetCU(), attr, fail_value);
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else
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return fail_value;
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}
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uint64_t DWARFBaseDIE::GetAttributeValueAsAddress(const dw_attr_t attr,
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uint64_t fail_value) const {
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if (IsValid())
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return m_die->GetAttributeValueAsAddress(GetCU(), attr, fail_value);
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else
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return fail_value;
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}
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lldb::user_id_t DWARFBaseDIE::GetID() const {
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if (IsValid())
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return GetDWARF()->GetUID(*this);
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return LLDB_INVALID_UID;
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}
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const char *DWARFBaseDIE::GetName() const {
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if (IsValid())
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return m_die->GetName(m_cu);
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else
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return nullptr;
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}
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lldb::LanguageType DWARFBaseDIE::GetLanguage() const {
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if (IsValid())
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return m_cu->GetLanguageType();
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else
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return lldb::eLanguageTypeUnknown;
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}
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lldb::ModuleSP DWARFBaseDIE::GetModule() const {
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SymbolFileDWARF *dwarf = GetDWARF();
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if (dwarf)
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return dwarf->GetObjectFile()->GetModule();
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else
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return lldb::ModuleSP();
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}
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dw_offset_t DWARFBaseDIE::GetOffset() const {
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if (IsValid())
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return m_die->GetOffset();
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else
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return DW_INVALID_OFFSET;
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}
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SymbolFileDWARF *DWARFBaseDIE::GetDWARF() const {
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if (m_cu)
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return &m_cu->GetSymbolFileDWARF();
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else
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return nullptr;
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}
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lldb_private::TypeSystem *DWARFBaseDIE::GetTypeSystem() const {
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if (m_cu)
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return m_cu->GetTypeSystem();
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else
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return nullptr;
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}
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DWARFASTParser *DWARFBaseDIE::GetDWARFParser() const {
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lldb_private::TypeSystem *type_system = GetTypeSystem();
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if (type_system)
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return type_system->GetDWARFParser();
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else
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return nullptr;
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}
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bool DWARFBaseDIE::HasChildren() const {
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return m_die && m_die->HasChildren();
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}
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bool DWARFBaseDIE::Supports_DW_AT_APPLE_objc_complete_type() const {
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return IsValid() && GetDWARF()->Supports_DW_AT_APPLE_objc_complete_type(m_cu);
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}
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size_t DWARFBaseDIE::GetAttributes(DWARFAttributes &attributes,
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uint32_t depth) const {
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if (IsValid())
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return m_die->GetAttributes(m_cu, attributes, depth);
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if (depth == 0)
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attributes.Clear();
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return 0;
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}
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bool operator==(const DWARFBaseDIE &lhs, const DWARFBaseDIE &rhs) {
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return lhs.GetDIE() == rhs.GetDIE() && lhs.GetCU() == rhs.GetCU();
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}
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bool operator!=(const DWARFBaseDIE &lhs, const DWARFBaseDIE &rhs) {
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return !(lhs == rhs);
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}
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const DWARFDataExtractor &DWARFBaseDIE::GetData() const {
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// Clients must check if this DIE is valid before calling this function.
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assert(IsValid());
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return m_cu->GetData();
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}
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