eee309068e
When LLVM error handling was introduced to the parsing of the .debug_aranges it would cause major issues if any DWARFDebugArangeSet::extract() calls returned any errors. The code in DWARFDebugInfo::GetCompileUnitAranges() would end up calling DWARFDebugAranges::extract() which would return an error if _any_ DWARFDebugArangeSet had any errors, but it default constructed a DWARFDebugAranges object into DWARFDebugInfo::m_cu_aranges_up and populated it partially, and returned an error prior to finishing much needed functionality in the DWARFDebugInfo::GetCompileUnitAranges() function. Subsequent callers to this function would see that the DWARFDebugInfo::m_cu_aranges_up was actually valid and return this partially populated DWARFDebugAranges reference _and_ it would not be sorted or minimized. This above bugs would cause an incomplete .debug_aranges parsing, it would skip manually parsing any compile units for ranges, and would not sort the DWARFDebugAranges in m_cu_aranges_up. This bug would also cause breakpoints set by file and line to fail to set correctly if a symbol context for an address could not be resolved properly, which the incomplete and unsorted DWARFDebugAranges object that DWARFDebugInfo::GetCompileUnitAranges() returned would cause symbol context lookups resolved by address (breakpoint address) to fail to find any DWARF debug info for a given address. This patch fixes all of the issues that I found: - DWARFDebugInfo::GetCompileUnitAranges() no longer returns a "llvm::Expected<DWARFDebugAranges &>", but just returns a "const DWARFDebugAranges &". Why? Because this code contained a fallback that would parse all of the valid DWARFDebugArangeSet objects, and would check which compile units had valid .debug_aranges set entries, and manually build an address ranges table using DWARFUnit::BuildAddressRangeTable(). If we return an error because any DWARFDebugArangeSet has any errors, then we don't do any of this code. Now we parse all DWARFDebugArangeSet objects that have no errors, if any calls to DWARFDebugArangeSet::extract() return errors, we skip that DWARFDebugArangeSet so that we can use the fallback call to DWARFUnit::BuildAddressRangeTable(). Since DWARFDebugInfo::GetCompileUnitAranges() needs to parse what it can from the .debug_aranges and build address ranges tables for any compile units that don't have any .debug_aranges sets, everything now works as expected. - Fix an issue where a DWARFDebugArangeSet contains multiple terminator entries. The LLVM parser and llvm-dwarfdump properly warn about this because it happens with linux compilers and linkers and was the original cause of the bug I am fixing here. We now correctly warn about this issue if "log enable dwarf info" is enabled, but we continue to parse the DWARFDebugArangeSet correctly so we don't lose data that is contained in the .debug_aranges section. - DWARFDebugAranges::extract() no longer returns a llvm::Error because we need to be able to parse all of the valid DWARFDebugArangeSet objects. It also will correctly skip a DWARFDebugArangeSet object that has errors in the middle of the stream by setting the start offsets of each DWARFDebugArangeSet to be calculated by the previous DWARFDebugArangeSet::extract() calculated offset that uses the header which contains the length of the DWARFDebugArangeSet. This means if do we run into real errors while parsing individual DWARFDebugArangeSet objects, we can continue to parse the rest of the validly encoded DWARFDebugArangeSet objects in the .debug_aranges section. This will allow LLDB to parse DWARF that contains a possibly newer .debug_aranges set format than LLDB currently supports because we will error out for the parsing of the DWARFDebugArangeSet, but be able to skip to the next DWARFDebugArangeSet object using the "DWARFDebugArangeSet.m_header.length" field to calculate the next starting offset. Tests were added to cover all new functionality. Differential Revision: https://reviews.llvm.org/D99401
67 lines
2.3 KiB
C++
67 lines
2.3 KiB
C++
//===-- DWARFDebugArangeSet.h -----------------------------------*- 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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#ifndef LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_DWARFDEBUGARANGESET_H
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#define LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_DWARFDEBUGARANGESET_H
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#include "lldb/Core/dwarf.h"
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#include <cstdint>
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#include <vector>
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class DWARFDebugArangeSet {
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public:
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struct Header {
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/// The total length of the entries for that set, not including the length
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/// field itself.
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uint32_t length = 0;
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/// The DWARF version number.
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uint16_t version = 0;
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/// The offset from the beginning of the .debug_info section of the
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/// compilation unit entry referenced by the table.
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uint32_t cu_offset = 0;
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/// The size in bytes of an address on the target architecture. For
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/// segmented addressing, this is the size of the offset portion of the
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/// address.
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uint8_t addr_size = 0;
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/// The size in bytes of a segment descriptor on the target architecture.
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/// If the target system uses a flat address space, this value is 0.
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uint8_t seg_size = 0;
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};
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struct Descriptor {
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dw_addr_t address;
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dw_addr_t length;
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dw_addr_t end_address() const { return address + length; }
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};
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DWARFDebugArangeSet();
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void Clear();
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void SetOffset(uint32_t offset) { m_offset = offset; }
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llvm::Error extract(const lldb_private::DWARFDataExtractor &data,
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lldb::offset_t *offset_ptr);
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dw_offset_t FindAddress(dw_addr_t address) const;
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size_t NumDescriptors() const { return m_arange_descriptors.size(); }
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const Header &GetHeader() const { return m_header; }
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dw_offset_t GetNextOffset() const { return m_next_offset; }
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const Descriptor &GetDescriptorRef(uint32_t i) const {
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return m_arange_descriptors[i];
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}
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protected:
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typedef std::vector<Descriptor> DescriptorColl;
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typedef DescriptorColl::iterator DescriptorIter;
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typedef DescriptorColl::const_iterator DescriptorConstIter;
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dw_offset_t m_offset;
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dw_offset_t m_next_offset;
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Header m_header;
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DescriptorColl m_arange_descriptors;
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};
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#endif // LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_DWARFDEBUGARANGESET_H
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