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

   1 //===-- DWARFLocationExpression.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 "DWARFLocationExpression.h"
  10
  11 #include "lldb/Core/Module.h"
  12 #include "lldb/Core/Section.h"
  13 #include "lldb/Expression/DWARFExpression.h"
  14 #include "lldb/Utility/ArchSpec.h"
  15 #include "lldb/Utility/DataBufferHeap.h"
  16 #include "lldb/Utility/StreamBuffer.h"
  17
  18 #include "llvm/BinaryFormat/Dwarf.h"
  19 #include "llvm/DebugInfo/CodeView/TypeDeserializer.h"
  20 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
  21 #include "llvm/DebugInfo/PDB/Native/TpiStream.h"
  22 #include "llvm/Support/Endian.h"
  23
  24 #include "PdbUtil.h"
  25 #include "CodeViewRegisterMapping.h"
  26 #include "PdbFPOProgramToDWARFExpression.h"
  27 #include <optional>
  28
  29 using namespace lldb;
  30 using namespace lldb_private;
  31 using namespace lldb_private::npdb;
  32 using namespace llvm::codeview;
  33 using namespace llvm::pdb;
  34
  35 uint32_t GetGenericRegisterNumber(llvm::codeview::RegisterId register_id) {
  36   if (register_id == llvm::codeview::RegisterId::VFRAME)
  37     return LLDB_REGNUM_GENERIC_FP;
  38
  39   return LLDB_INVALID_REGNUM;
  40 }
  41
  42 static uint32_t GetRegisterNumber(llvm::Triple::ArchType arch_type,
  43                                   llvm::codeview::RegisterId register_id,
  44                                   RegisterKind &register_kind) {
  45   register_kind = eRegisterKindLLDB;
  46   uint32_t reg_num = GetLLDBRegisterNumber(arch_type, register_id);
  47   if (reg_num != LLDB_INVALID_REGNUM)
  48     return reg_num;
  49
  50   register_kind = eRegisterKindGeneric;
  51   return GetGenericRegisterNumber(register_id);
  52 }
  53
  54 static bool IsSimpleTypeSignedInteger(SimpleTypeKind kind) {
  55   switch (kind) {
  56   case SimpleTypeKind::Int128:
  57   case SimpleTypeKind::Int64:
  58   case SimpleTypeKind::Int64Quad:
  59   case SimpleTypeKind::Int32:
  60   case SimpleTypeKind::Int32Long:
  61   case SimpleTypeKind::Int16:
  62   case SimpleTypeKind::Int16Short:
  63   case SimpleTypeKind::Float128:
  64   case SimpleTypeKind::Float80:
  65   case SimpleTypeKind::Float64:
  66   case SimpleTypeKind::Float32:
  67   case SimpleTypeKind::Float16:
  68   case SimpleTypeKind::NarrowCharacter:
  69   case SimpleTypeKind::SignedCharacter:
  70   case SimpleTypeKind::SByte:
  71     return true;
  72   default:
  73     return false;
  74   }
  75 }
  76
  77 static std::pair<size_t, bool> GetIntegralTypeInfo(TypeIndex ti,
  78                                                    TpiStream &tpi) {
  79   if (ti.isSimple()) {
  80     SimpleTypeKind stk = ti.getSimpleKind();
  81     return {GetTypeSizeForSimpleKind(stk), IsSimpleTypeSignedInteger(stk)};
  82   }
  83
  84   CVType cvt = tpi.getType(ti);
  85   switch (cvt.kind()) {
  86   case LF_MODIFIER: {
  87     ModifierRecord mfr;
  88     llvm::cantFail(TypeDeserializer::deserializeAs<ModifierRecord>(cvt, mfr));
  89     return GetIntegralTypeInfo(mfr.ModifiedType, tpi);
  90   }
  91   case LF_POINTER: {
  92     PointerRecord pr;
  93     llvm::cantFail(TypeDeserializer::deserializeAs<PointerRecord>(cvt, pr));
  94     return GetIntegralTypeInfo(pr.ReferentType, tpi);
  95   }
  96   case LF_ENUM: {
  97     EnumRecord er;
  98     llvm::cantFail(TypeDeserializer::deserializeAs<EnumRecord>(cvt, er));
  99     return GetIntegralTypeInfo(er.UnderlyingType, tpi);
 100   }
 101   default:
 102     assert(false && "Type is not integral!");
 103     return {0, false};
 104   }
 105 }
 106
 107 template <typename StreamWriter>
 108 static DWARFExpression MakeLocationExpressionInternal(lldb::ModuleSP module,
 109                                                       StreamWriter &&writer) {
 110   const ArchSpec &architecture = module->GetArchitecture();
 111   ByteOrder byte_order = architecture.GetByteOrder();
 112   uint32_t address_size = architecture.GetAddressByteSize();
 113   uint32_t byte_size = architecture.GetDataByteSize();
 114   if (byte_order == eByteOrderInvalid || address_size == 0)
 115     return DWARFExpression();
 116
 117   RegisterKind register_kind = eRegisterKindDWARF;
 118   StreamBuffer<32> stream(Stream::eBinary, address_size, byte_order);
 119
 120   if (!writer(stream, register_kind))
 121     return DWARFExpression();
 122
 123   DataBufferSP buffer =
 124       std::make_shared<DataBufferHeap>(stream.GetData(), stream.GetSize());
 125   DataExtractor extractor(buffer, byte_order, address_size, byte_size);
 126   DWARFExpression result(extractor);
 127   result.SetRegisterKind(register_kind);
 128
 129   return result;
 130 }
 131
 132 static bool MakeRegisterBasedLocationExpressionInternal(
 133     Stream &stream, llvm::codeview::RegisterId reg, RegisterKind &register_kind,
 134     std::optional<int32_t> relative_offset, lldb::ModuleSP module) {
 135   uint32_t reg_num = GetRegisterNumber(module->GetArchitecture().GetMachine(),
 136                                        reg, register_kind);
 137   if (reg_num == LLDB_INVALID_REGNUM)
 138     return false;
 139
 140   if (reg_num > 31) {
 141     llvm::dwarf::LocationAtom base =
 142         relative_offset ? llvm::dwarf::DW_OP_bregx : llvm::dwarf::DW_OP_regx;
 143     stream.PutHex8(base);
 144     stream.PutULEB128(reg_num);
 145   } else {
 146     llvm::dwarf::LocationAtom base =
 147         relative_offset ? llvm::dwarf::DW_OP_breg0 : llvm::dwarf::DW_OP_reg0;
 148     stream.PutHex8(base + reg_num);
 149   }
 150
 151   if (relative_offset)
 152     stream.PutSLEB128(*relative_offset);
 153
 154   return true;
 155 }
 156
 157 static DWARFExpression MakeRegisterBasedLocationExpressionInternal(
 158     llvm::codeview::RegisterId reg, std::optional<int32_t> relative_offset,
 159     lldb::ModuleSP module) {
 160   return MakeLocationExpressionInternal(
 161       module, [&](Stream &stream, RegisterKind &register_kind) -> bool {
 162         return MakeRegisterBasedLocationExpressionInternal(
 163             stream, reg, register_kind, relative_offset, module);
 164       });
 165 }
 166
 167 DWARFExpression lldb_private::npdb::MakeEnregisteredLocationExpression(
 168     llvm::codeview::RegisterId reg, lldb::ModuleSP module) {
 169   return MakeRegisterBasedLocationExpressionInternal(reg, std::nullopt, module);
 170 }
 171
 172 DWARFExpression lldb_private::npdb::MakeRegRelLocationExpression(
 173     llvm::codeview::RegisterId reg, int32_t offset, lldb::ModuleSP module) {
 174   return MakeRegisterBasedLocationExpressionInternal(reg, offset, module);
 175 }
 176
 177 static bool EmitVFrameEvaluationDWARFExpression(
 178     llvm::StringRef program, llvm::Triple::ArchType arch_type, Stream &stream) {
 179   // VFrame value always stored in $TO pseudo-register
 180   return TranslateFPOProgramToDWARFExpression(program, "$T0", arch_type,
 181                                               stream);
 182 }
 183
 184 DWARFExpression lldb_private::npdb::MakeVFrameRelLocationExpression(
 185     llvm::StringRef fpo_program, int32_t offset, lldb::ModuleSP module) {
 186   return MakeLocationExpressionInternal(
 187       module, [&](Stream &stream, RegisterKind &register_kind) -> bool {
 188         const ArchSpec &architecture = module->GetArchitecture();
 189
 190         if (!EmitVFrameEvaluationDWARFExpression(fpo_program, architecture.GetMachine(),
 191                                                  stream))
 192           return false;
 193
 194         stream.PutHex8(llvm::dwarf::DW_OP_consts);
 195         stream.PutSLEB128(offset);
 196         stream.PutHex8(llvm::dwarf::DW_OP_plus);
 197
 198         register_kind = eRegisterKindLLDB;
 199
 200         return true;
 201       });
 202 }
 203
 204 DWARFExpression lldb_private::npdb::MakeGlobalLocationExpression(
 205     uint16_t section, uint32_t offset, ModuleSP module) {
 206   assert(section > 0);
 207   assert(module);
 208
 209   return MakeLocationExpressionInternal(
 210       module, [&](Stream &stream, RegisterKind &register_kind) -> bool {
 211         stream.PutHex8(llvm::dwarf::DW_OP_addr);
 212
 213         SectionList *section_list = module->GetSectionList();
 214         assert(section_list);
 215
 216         auto section_ptr = section_list->FindSectionByID(section);
 217         if (!section_ptr)
 218           return false;
 219
 220         stream.PutMaxHex64(section_ptr->GetFileAddress() + offset,
 221                            stream.GetAddressByteSize(), stream.GetByteOrder());
 222
 223         return true;
 224       });
 225 }
 226
 227 DWARFExpression lldb_private::npdb::MakeConstantLocationExpression(
 228     TypeIndex underlying_ti, TpiStream &tpi, const llvm::APSInt &constant,
 229     ModuleSP module) {
 230   const ArchSpec &architecture = module->GetArchitecture();
 231   uint32_t address_size = architecture.GetAddressByteSize();
 232
 233   size_t size = 0;
 234   bool is_signed = false;
 235   std::tie(size, is_signed) = GetIntegralTypeInfo(underlying_ti, tpi);
 236
 237   union {
 238     llvm::support::little64_t I;
 239     llvm::support::ulittle64_t U;
 240   } Value;
 241
 242   std::shared_ptr<DataBufferHeap> buffer = std::make_shared<DataBufferHeap>();
 243   buffer->SetByteSize(size);
 244
 245   llvm::ArrayRef<uint8_t> bytes;
 246   if (is_signed) {
 247     Value.I = constant.getSExtValue();
 248   } else {
 249     Value.U = constant.getZExtValue();
 250   }
 251
 252   bytes = llvm::ArrayRef(reinterpret_cast<const uint8_t *>(&Value), 8)
 253               .take_front(size);
 254   buffer->CopyData(bytes.data(), size);
 255   DataExtractor extractor(buffer, lldb::eByteOrderLittle, address_size);
 256   DWARFExpression result(extractor);
 257   return result;
 258 }
 259
 260 DWARFExpression
 261 lldb_private::npdb::MakeEnregisteredLocationExpressionForComposite(
 262     const std::map<uint64_t, MemberValLocation> &offset_to_location,
 263     std::map<uint64_t, size_t> &offset_to_size, size_t total_size,
 264     lldb::ModuleSP module) {
 265   return MakeLocationExpressionInternal(
 266       module, [&](Stream &stream, RegisterKind &register_kind) -> bool {
 267         size_t cur_offset = 0;
 268         bool is_simple_type = offset_to_size.empty();
 269         // Iterate through offset_to_location because offset_to_size might be
 270         // empty if the variable is a simple type.
 271         for (const auto &offset_loc : offset_to_location) {
 272           if (cur_offset < offset_loc.first) {
 273             stream.PutHex8(llvm::dwarf::DW_OP_piece);
 274             stream.PutULEB128(offset_loc.first - cur_offset);
 275             cur_offset = offset_loc.first;
 276           }
 277           MemberValLocation loc = offset_loc.second;
 278           std::optional<int32_t> offset =
 279               loc.is_at_reg ? std::nullopt
 280                             : std::optional<int32_t>(loc.reg_offset);
 281           if (!MakeRegisterBasedLocationExpressionInternal(
 282                   stream, (RegisterId)loc.reg_id, register_kind, offset,
 283                   module))
 284             return false;
 285           if (!is_simple_type) {
 286             stream.PutHex8(llvm::dwarf::DW_OP_piece);
 287             stream.PutULEB128(offset_to_size[offset_loc.first]);
 288             cur_offset = offset_loc.first + offset_to_size[offset_loc.first];
 289           }
 290         }
 291         // For simple type, it specifies the byte size of the value described by
 292         // the previous dwarf expr. For udt, it's the remaining byte size at end
 293         // of a struct.
 294         if (total_size > cur_offset) {
 295           stream.PutHex8(llvm::dwarf::DW_OP_piece);
 296           stream.PutULEB128(total_size - cur_offset);
 297         }
 298         return true;
 299       });
 300 }