lldb/source/Plugins/SymbolFile/NativePDB/PdbIndex.cpp

   1 //===-- PdbIndex.cpp ------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "PdbIndex.h"
  10 #include "PdbUtil.h"
  11
  12 #include "llvm/DebugInfo/CodeView/SymbolDeserializer.h"
  13 #include "llvm/DebugInfo/PDB/Native/DbiStream.h"
  14 #include "llvm/DebugInfo/PDB/Native/GlobalsStream.h"
  15 #include "llvm/DebugInfo/PDB/Native/ISectionContribVisitor.h"
  16 #include "llvm/DebugInfo/PDB/Native/PDBFile.h"
  17 #include "llvm/DebugInfo/PDB/Native/PublicsStream.h"
  18 #include "llvm/DebugInfo/PDB/Native/SymbolStream.h"
  19 #include "llvm/DebugInfo/PDB/Native/TpiStream.h"
  20 #include "llvm/Object/COFF.h"
  21 #include "llvm/Support/Error.h"
  22
  23 #include "lldb/Utility/LLDBAssert.h"
  24 #include "lldb/lldb-defines.h"
  25 #include <optional>
  26
  27 using namespace lldb_private;
  28 using namespace lldb_private::npdb;
  29 using namespace llvm::codeview;
  30 using namespace llvm::pdb;
  31
  32 PdbIndex::PdbIndex() : m_cus(*this), m_va_to_modi(m_allocator) {}
  33
  34 #define ASSIGN_PTR_OR_RETURN(result_ptr, expr)                                 \
  35   {                                                                            \
  36     auto expected_result = expr;                                               \
  37     if (!expected_result)                                                      \
  38       return expected_result.takeError();                                      \
  39     result_ptr = &expected_result.get();                                       \
  40   }
  41
  42 llvm::Expected<std::unique_ptr<PdbIndex>>
  43 PdbIndex::create(llvm::pdb::PDBFile *file) {
  44   lldbassert(file);
  45
  46   std::unique_ptr<PdbIndex> result(new PdbIndex());
  47   ASSIGN_PTR_OR_RETURN(result->m_dbi, file->getPDBDbiStream());
  48   ASSIGN_PTR_OR_RETURN(result->m_tpi, file->getPDBTpiStream());
  49   ASSIGN_PTR_OR_RETURN(result->m_ipi, file->getPDBIpiStream());
  50   ASSIGN_PTR_OR_RETURN(result->m_info, file->getPDBInfoStream());
  51   ASSIGN_PTR_OR_RETURN(result->m_publics, file->getPDBPublicsStream());
  52   ASSIGN_PTR_OR_RETURN(result->m_globals, file->getPDBGlobalsStream());
  53   ASSIGN_PTR_OR_RETURN(result->m_symrecords, file->getPDBSymbolStream());
  54
  55   result->m_tpi->buildHashMap();
  56
  57   result->m_file = file;
  58
  59   return std::move(result);
  60 }
  61
  62 lldb::addr_t PdbIndex::MakeVirtualAddress(uint16_t segment,
  63                                           uint32_t offset) const {
  64   uint32_t max_section = dbi().getSectionHeaders().size();
  65   // Segment indices are 1-based.
  66   // If this is an absolute symbol, it's indicated by the magic section index
  67   // |max_section+1|.  In this case, the offset is meaningless, so just return.
  68   if (segment == 0 || segment > max_section)
  69     return LLDB_INVALID_ADDRESS;
  70
  71   const llvm::object::coff_section &cs = dbi().getSectionHeaders()[segment - 1];
  72   return m_load_address + static_cast<lldb::addr_t>(cs.VirtualAddress) +
  73          static_cast<lldb::addr_t>(offset);
  74 }
  75
  76 std::optional<uint16_t> PdbIndex::GetModuleIndexForAddr(uint16_t segment,
  77                                                         uint32_t offset) const {
  78   return GetModuleIndexForVa(MakeVirtualAddress(segment, offset));
  79 }
  80
  81 std::optional<uint16_t> PdbIndex::GetModuleIndexForVa(lldb::addr_t va) const {
  82   auto iter = m_va_to_modi.find(va);
  83   if (iter == m_va_to_modi.end())
  84     return std::nullopt;
  85
  86   return iter.value();
  87 }
  88
  89 void PdbIndex::ParseSectionContribs() {
  90   class Visitor : public ISectionContribVisitor {
  91     PdbIndex &m_ctx;
  92     llvm::IntervalMap<uint64_t, uint16_t> &m_imap;
  93
  94   public:
  95     Visitor(PdbIndex &ctx, llvm::IntervalMap<uint64_t, uint16_t> &imap)
  96         : m_ctx(ctx), m_imap(imap) {}
  97
  98     void visit(const SectionContrib &C) override {
  99       if (C.Size == 0)
 100         return;
 101
 102       uint64_t va = m_ctx.MakeVirtualAddress(C.ISect, C.Off);
 103       if (va == LLDB_INVALID_ADDRESS)
 104         return;
 105       uint64_t end = va + C.Size;
 106       // IntervalMap's start and end represent a closed range, not a half-open
 107       // range, so we have to subtract 1.
 108       m_imap.insert(va, end - 1, C.Imod);
 109     }
 110     void visit(const SectionContrib2 &C) override { visit(C.Base); }
 111   };
 112   Visitor v(*this, m_va_to_modi);
 113   dbi().visitSectionContributions(v);
 114 }
 115
 116 void PdbIndex::BuildAddrToSymbolMap(CompilandIndexItem &cci) {
 117   lldbassert(cci.m_symbols_by_va.empty() &&
 118              "Addr to symbol map is already built!");
 119   uint16_t modi = cci.m_id.modi;
 120   const CVSymbolArray &syms = cci.m_debug_stream.getSymbolArray();
 121   for (auto iter = syms.begin(); iter != syms.end(); ++iter) {
 122     if (!SymbolHasAddress(*iter))
 123       continue;
 124
 125     SegmentOffset so = GetSegmentAndOffset(*iter);
 126     lldb::addr_t va = MakeVirtualAddress(so.segment, so.offset);
 127     if (va == LLDB_INVALID_ADDRESS)
 128       continue;
 129
 130     PdbCompilandSymId cu_sym_id(modi, iter.offset());
 131
 132     // It's rare, but we could have multiple symbols with the same address
 133     // because of identical comdat folding.  Right now, the first one will win.
 134     cci.m_symbols_by_va.insert(std::make_pair(va, PdbSymUid(cu_sym_id)));
 135   }
 136 }
 137
 138 std::vector<SymbolAndUid> PdbIndex::FindSymbolsByVa(lldb::addr_t va) {
 139   std::vector<SymbolAndUid> result;
 140
 141   std::optional<uint16_t> modi = GetModuleIndexForVa(va);
 142   if (!modi)
 143     return result;
 144
 145   CompilandIndexItem &cci = compilands().GetOrCreateCompiland(*modi);
 146   if (cci.m_symbols_by_va.empty())
 147     BuildAddrToSymbolMap(cci);
 148
 149   // The map is sorted by starting address of the symbol.  So for example
 150   // we could (in theory) have this situation
 151   //
 152   // [------------------]
 153   //    [----------]
 154   //      [-----------]
 155   //          [-------------]
 156   //            [----]
 157   //               [-----]
 158   //             ^ Address we're searching for
 159   // In order to find this, we use the upper_bound of the key value which would
 160   // be the first symbol whose starting address is higher than the element we're
 161   // searching for.
 162
 163   auto ub = cci.m_symbols_by_va.upper_bound(va);
 164
 165   for (auto iter = cci.m_symbols_by_va.begin(); iter != ub; ++iter) {
 166     PdbCompilandSymId cu_sym_id = iter->second.asCompilandSym();
 167     CVSymbol sym = ReadSymbolRecord(cu_sym_id);
 168
 169     SegmentOffsetLength sol;
 170     if (SymbolIsCode(sym))
 171       sol = GetSegmentOffsetAndLength(sym);
 172     else
 173       sol.so = GetSegmentAndOffset(sym);
 174
 175     lldb::addr_t start = MakeVirtualAddress(sol.so.segment, sol.so.offset);
 176     if (start == LLDB_INVALID_ADDRESS)
 177       continue;
 178
 179     lldb::addr_t end = start + sol.length;
 180     if (va >= start && va < end)
 181       result.push_back({std::move(sym), iter->second});
 182   }
 183
 184   return result;
 185 }
 186
 187 CVSymbol PdbIndex::ReadSymbolRecord(PdbCompilandSymId cu_sym) const {
 188   const CompilandIndexItem *cci = compilands().GetCompiland(cu_sym.modi);
 189   auto iter = cci->m_debug_stream.getSymbolArray().at(cu_sym.offset);
 190   lldbassert(iter != cci->m_debug_stream.getSymbolArray().end());
 191   return *iter;
 192 }
 193
 194 CVSymbol PdbIndex::ReadSymbolRecord(PdbGlobalSymId global) const {
 195   return symrecords().readRecord(global.offset);
 196 }