Revert "[LLDB] Impove ObjectFileELF's .dynamic parsing and usage. (#101237)"

This reverts commit 28ba8a56b6fb9ec61897fa84369f46e43be94c03.

Reverting since this broke the buildbot at
https://green.lab.llvm.org/job/llvm.org/view/LLDB/job/as-lldb-cmake/9352/.

1 files changed, 120 insertions, 302 deletions

diff --git a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
index 414ac61..890db5c 100644
--- a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -419,35 +419,19 @@ ObjectFile *ObjectFileELF::CreateInstance(const lldb::ModuleSP &module_sp,
 ObjectFile *ObjectFileELF::CreateMemoryInstance(
     const lldb::ModuleSP &module_sp, WritableDataBufferSP data_sp,
     const lldb::ProcessSP &process_sp, lldb::addr_t header_addr) {
-  if (!data_sp || data_sp->GetByteSize() < (llvm::ELF::EI_NIDENT))
-    return nullptr;
-  const uint8_t *magic = data_sp->GetBytes();
-  if (!ELFHeader::MagicBytesMatch(magic))
-    return nullptr;
-  // Read the ELF header first so we can figure out how many bytes we need
-  // to read to get as least the ELF header + program headers.
-  DataExtractor data;
-  data.SetData(data_sp);
-  elf::ELFHeader hdr;
-  lldb::offset_t offset = 0;
-  if (!hdr.Parse(data, &offset))
-    return nullptr;
-
-  // Make sure the address size is set correctly in the ELF header.
-  if (!hdr.Is32Bit() && !hdr.Is64Bit())
-    return nullptr;
-  // Figure out where the program headers end and read enough bytes to get the
-  // program headers in their entirety.
-  lldb::offset_t end_phdrs = hdr.e_phoff + (hdr.e_phentsize * hdr.e_phnum);
-  if (end_phdrs > data_sp->GetByteSize())
-    data_sp = ReadMemory(process_sp, header_addr, end_phdrs);
-
-  std::unique_ptr<ObjectFileELF> objfile_up(
-      new ObjectFileELF(module_sp, data_sp, process_sp, header_addr));
-  ArchSpec spec = objfile_up->GetArchitecture();
-  if (spec && objfile_up->SetModulesArchitecture(spec))
-    return objfile_up.release();
-
+  if (data_sp && data_sp->GetByteSize() > (llvm::ELF::EI_NIDENT)) {
+    const uint8_t *magic = data_sp->GetBytes();
+    if (ELFHeader::MagicBytesMatch(magic)) {
+      unsigned address_size = ELFHeader::AddressSizeInBytes(magic);
+      if (address_size == 4 || address_size == 8) {
+        std::unique_ptr<ObjectFileELF> objfile_up(
+            new ObjectFileELF(module_sp, data_sp, process_sp, header_addr));
+        ArchSpec spec = objfile_up->GetArchitecture();
+        if (spec && objfile_up->SetModulesArchitecture(spec))
+          return objfile_up.release();
+      }
+    }
+  }
   return nullptr;
 }
 
@@ -889,37 +873,42 @@ Address ObjectFileELF::GetImageInfoAddress(Target *target) {
   if (!section_list)
     return Address();
 
-  for (size_t i = 0; i < m_dynamic_symbols.size(); ++i) {
-    const ELFDynamic &symbol = m_dynamic_symbols[i].symbol;
+  // Find the SHT_DYNAMIC (.dynamic) section.
+  SectionSP dynsym_section_sp(
+      section_list->FindSectionByType(eSectionTypeELFDynamicLinkInfo, true));
+  if (!dynsym_section_sp)
+    return Address();
+  assert(dynsym_section_sp->GetObjectFile() == this);
 
-    if (symbol.d_tag != DT_DEBUG && symbol.d_tag != DT_MIPS_RLD_MAP &&
-        symbol.d_tag != DT_MIPS_RLD_MAP_REL)
-      continue;
+  user_id_t dynsym_id = dynsym_section_sp->GetID();
+  const ELFSectionHeaderInfo *dynsym_hdr = GetSectionHeaderByIndex(dynsym_id);
+  if (!dynsym_hdr)
+    return Address();
 
-    // Compute the offset as the number of previous entries plus the size of
-    // d_tag.
-    const addr_t offset = (i * 2 + 1) * GetAddressByteSize();
-    const addr_t d_file_addr = m_dynamic_base_addr + offset;
-    Address d_addr;
-    if (d_addr.ResolveAddressUsingFileSections(d_file_addr, GetSectionList()))
-      return Address();
-    if (symbol.d_tag == DT_DEBUG)
-      return d_addr;
+  for (size_t i = 0; i < m_dynamic_symbols.size(); ++i) {
+    ELFDynamic &symbol = m_dynamic_symbols[i];
 
+    if (symbol.d_tag == DT_DEBUG) {
+      // Compute the offset as the number of previous entries plus the size of
+      // d_tag.
+      addr_t offset = i * dynsym_hdr->sh_entsize + GetAddressByteSize();
+      return Address(dynsym_section_sp, offset);
+    }
     // MIPS executables uses DT_MIPS_RLD_MAP_REL to support PIE. DT_MIPS_RLD_MAP
     // exists in non-PIE.
-    if ((symbol.d_tag == DT_MIPS_RLD_MAP ||
-         symbol.d_tag == DT_MIPS_RLD_MAP_REL) &&
-        target) {
-      const addr_t d_load_addr = d_addr.GetLoadAddress(target);
-      if (d_load_addr == LLDB_INVALID_ADDRESS)
+    else if ((symbol.d_tag == DT_MIPS_RLD_MAP ||
+              symbol.d_tag == DT_MIPS_RLD_MAP_REL) &&
+             target) {
+      addr_t offset = i * dynsym_hdr->sh_entsize + GetAddressByteSize();
+      addr_t dyn_base = dynsym_section_sp->GetLoadBaseAddress(target);
+      if (dyn_base == LLDB_INVALID_ADDRESS)
         return Address();
 
       Status error;
       if (symbol.d_tag == DT_MIPS_RLD_MAP) {
         // DT_MIPS_RLD_MAP tag stores an absolute address of the debug pointer.
         Address addr;
-        if (target->ReadPointerFromMemory(d_load_addr, error, addr, true))
+        if (target->ReadPointerFromMemory(dyn_base + offset, error, addr, true))
           return addr;
       }
       if (symbol.d_tag == DT_MIPS_RLD_MAP_REL) {
@@ -927,17 +916,18 @@ Address ObjectFileELF::GetImageInfoAddress(Target *target) {
         // relative to the address of the tag.
         uint64_t rel_offset;
         rel_offset = target->ReadUnsignedIntegerFromMemory(
-            d_load_addr, GetAddressByteSize(), UINT64_MAX, error, true);
+            dyn_base + offset, GetAddressByteSize(), UINT64_MAX, error, true);
         if (error.Success() && rel_offset != UINT64_MAX) {
           Address addr;
           addr_t debug_ptr_address =
-              d_load_addr - GetAddressByteSize() + rel_offset;
+              dyn_base + (offset - GetAddressByteSize()) + rel_offset;
           addr.SetOffset(debug_ptr_address);
           return addr;
         }
       }
     }
   }
+
   return Address();
 }
 
@@ -980,23 +970,62 @@ Address ObjectFileELF::GetBaseAddress() {
   return LLDB_INVALID_ADDRESS;
 }
 
+// ParseDependentModules
 size_t ObjectFileELF::ParseDependentModules() {
   if (m_filespec_up)
     return m_filespec_up->GetSize();
 
   m_filespec_up = std::make_unique<FileSpecList>();
 
-  if (ParseDynamicSymbols()) {
-    for (const auto &entry : m_dynamic_symbols) {
-      if (entry.symbol.d_tag != DT_NEEDED)
+  if (!ParseSectionHeaders())
+    return 0;
+
+  SectionList *section_list = GetSectionList();
+  if (!section_list)
+    return 0;
+
+  // Find the SHT_DYNAMIC section.
+  Section *dynsym =
+      section_list->FindSectionByType(eSectionTypeELFDynamicLinkInfo, true)
+          .get();
+  if (!dynsym)
+    return 0;
+  assert(dynsym->GetObjectFile() == this);
+
+  const ELFSectionHeaderInfo *header = GetSectionHeaderByIndex(dynsym->GetID());
+  if (!header)
+    return 0;
+  // sh_link: section header index of string table used by entries in the
+  // section.
+  Section *dynstr = section_list->FindSectionByID(header->sh_link).get();
+  if (!dynstr)
+    return 0;
+
+  DataExtractor dynsym_data;
+  DataExtractor dynstr_data;
+  if (ReadSectionData(dynsym, dynsym_data) &&
+      ReadSectionData(dynstr, dynstr_data)) {
+    ELFDynamic symbol;
+    const lldb::offset_t section_size = dynsym_data.GetByteSize();
+    lldb::offset_t offset = 0;
+
+    // The only type of entries we are concerned with are tagged DT_NEEDED,
+    // yielding the name of a required library.
+    while (offset < section_size) {
+      if (!symbol.Parse(dynsym_data, &offset))
+        break;
+
+      if (symbol.d_tag != DT_NEEDED)
         continue;
-      if (!entry.name.empty()) {
-        FileSpec file_spec(entry.name);
-        FileSystem::Instance().Resolve(file_spec);
-        m_filespec_up->Append(file_spec);
-      }
+
+      uint32_t str_index = static_cast<uint32_t>(symbol.d_val);
+      const char *lib_name = dynstr_data.PeekCStr(str_index);
+      FileSpec file_spec(lib_name);
+      FileSystem::Instance().Resolve(file_spec);
+      m_filespec_up->Append(file_spec);
     }
   }
+
   return m_filespec_up->GetSize();
 }
 
@@ -2443,47 +2472,48 @@ size_t ObjectFileELF::ParseDynamicSymbols() {
   if (m_dynamic_symbols.size())
     return m_dynamic_symbols.size();
 
-  std::optional<DataExtractor> dynamic_data = GetDynamicData();
-  if (!dynamic_data)
+  SectionList *section_list = GetSectionList();
+  if (!section_list)
     return 0;
 
-  ELFDynamicWithName e;
-  lldb::offset_t cursor = 0;
-  while (e.symbol.Parse(*dynamic_data, &cursor)) {
-    m_dynamic_symbols.push_back(e);
-    if (e.symbol.d_tag == DT_NULL)
-      break;
-  }
-  if (std::optional<DataExtractor> dynstr_data = GetDynstrData()) {
-    for (ELFDynamicWithName &entry : m_dynamic_symbols) {
-      switch (entry.symbol.d_tag) {
-      case DT_NEEDED:
-      case DT_SONAME:
-      case DT_RPATH:
-      case DT_RUNPATH:
-      case DT_AUXILIARY:
-      case DT_FILTER: {
-        lldb::offset_t cursor = entry.symbol.d_val;
-        const char *name = dynstr_data->GetCStr(&cursor);
-        if (name)
-          entry.name = std::string(name);
-        break;
-      }
-      default:
+  // Find the SHT_DYNAMIC section.
+  Section *dynsym =
+      section_list->FindSectionByType(eSectionTypeELFDynamicLinkInfo, true)
+          .get();
+  if (!dynsym)
+    return 0;
+  assert(dynsym->GetObjectFile() == this);
+
+  ELFDynamic symbol;
+  DataExtractor dynsym_data;
+  if (ReadSectionData(dynsym, dynsym_data)) {
+    const lldb::offset_t section_size = dynsym_data.GetByteSize();
+    lldb::offset_t cursor = 0;
+
+    while (cursor < section_size) {
+      if (!symbol.Parse(dynsym_data, &cursor))
         break;
-      }
+
+      m_dynamic_symbols.push_back(symbol);
     }
   }
+
   return m_dynamic_symbols.size();
 }
 
 const ELFDynamic *ObjectFileELF::FindDynamicSymbol(unsigned tag) {
   if (!ParseDynamicSymbols())
     return nullptr;
-  for (const auto &entry : m_dynamic_symbols) {
-    if (entry.symbol.d_tag == tag)
-      return &entry.symbol;
+
+  DynamicSymbolCollIter I = m_dynamic_symbols.begin();
+  DynamicSymbolCollIter E = m_dynamic_symbols.end();
+  for (; I != E; ++I) {
+    ELFDynamic *symbol = &*I;
+
+    if (symbol->d_tag == tag)
+      return symbol;
   }
+
   return nullptr;
 }
 
@@ -3200,10 +3230,7 @@ void ObjectFileELF::Dump(Stream *s) {
   ArchSpec header_arch = GetArchitecture();
 
   *s << ", file = '" << m_file
-     << "', arch = " << header_arch.GetArchitectureName();
-  if (m_memory_addr != LLDB_INVALID_ADDRESS)
-    s->Printf(", addr = %#16.16" PRIx64, m_memory_addr);
-  s->EOL();
+     << "', arch = " << header_arch.GetArchitectureName() << "\n";
 
   DumpELFHeader(s, m_header);
   s->EOL();
@@ -3221,8 +3248,6 @@ void ObjectFileELF::Dump(Stream *s) {
   s->EOL();
   DumpDependentModules(s);
   s->EOL();
-  DumpELFDynamic(s);
-  s->EOL();
 }
 
 // DumpELFHeader
@@ -3467,111 +3492,6 @@ void ObjectFileELF::DumpDependentModules(lldb_private::Stream *s) {
   }
 }
 
-std::string static getDynamicTagAsString(uint16_t Arch, uint64_t Type) {
-#define DYNAMIC_STRINGIFY_ENUM(tag, value)                                     \
-  case value:                                                                  \
-    return #tag;
-
-#define DYNAMIC_TAG(n, v)
-  switch (Arch) {
-  case llvm::ELF::EM_AARCH64:
-    switch (Type) {
-#define AARCH64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef AARCH64_DYNAMIC_TAG
-    }
-    break;
-
-  case llvm::ELF::EM_HEXAGON:
-    switch (Type) {
-#define HEXAGON_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef HEXAGON_DYNAMIC_TAG
-    }
-    break;
-
-  case llvm::ELF::EM_MIPS:
-    switch (Type) {
-#define MIPS_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef MIPS_DYNAMIC_TAG
-    }
-    break;
-
-  case llvm::ELF::EM_PPC:
-    switch (Type) {
-#define PPC_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef PPC_DYNAMIC_TAG
-    }
-    break;
-
-  case llvm::ELF::EM_PPC64:
-    switch (Type) {
-#define PPC64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef PPC64_DYNAMIC_TAG
-    }
-    break;
-
-  case llvm::ELF::EM_RISCV:
-    switch (Type) {
-#define RISCV_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef RISCV_DYNAMIC_TAG
-    }
-    break;
-  }
-#undef DYNAMIC_TAG
-  switch (Type) {
-// Now handle all dynamic tags except the architecture specific ones
-#define AARCH64_DYNAMIC_TAG(name, value)
-#define MIPS_DYNAMIC_TAG(name, value)
-#define HEXAGON_DYNAMIC_TAG(name, value)
-#define PPC_DYNAMIC_TAG(name, value)
-#define PPC64_DYNAMIC_TAG(name, value)
-#define RISCV_DYNAMIC_TAG(name, value)
-// Also ignore marker tags such as DT_HIOS (maps to DT_VERNEEDNUM), etc.
-#define DYNAMIC_TAG_MARKER(name, value)
-#define DYNAMIC_TAG(name, value)                                               \
-  case value:                                                                  \
-    return #name;
-#include "llvm/BinaryFormat/DynamicTags.def"
-#undef DYNAMIC_TAG
-#undef AARCH64_DYNAMIC_TAG
-#undef MIPS_DYNAMIC_TAG
-#undef HEXAGON_DYNAMIC_TAG
-#undef PPC_DYNAMIC_TAG
-#undef PPC64_DYNAMIC_TAG
-#undef RISCV_DYNAMIC_TAG
-#undef DYNAMIC_TAG_MARKER
-#undef DYNAMIC_STRINGIFY_ENUM
-  default:
-    return "<unknown:>0x" + llvm::utohexstr(Type, true);
-  }
-}
-
-void ObjectFileELF::DumpELFDynamic(lldb_private::Stream *s) {
-  ParseDynamicSymbols();
-  if (m_dynamic_symbols.empty())
-    return;
-
-  s->PutCString(".dynamic:\n");
-  s->PutCString("IDX  d_tag            d_val/d_ptr\n");
-  s->PutCString("==== ---------------- ------------------\n");
-  uint32_t idx = 0;
-  for (const auto &entry : m_dynamic_symbols) {
-    s->Printf("[%2u] ", idx++);
-    s->Printf(
-        "%-16s 0x%16.16" PRIx64,
-        getDynamicTagAsString(m_header.e_machine, entry.symbol.d_tag).c_str(),
-        entry.symbol.d_ptr);
-    if (!entry.name.empty())
-      s->Printf(" \"%s\"", entry.name.c_str());
-    s->EOL();
-  }
-}
-
 ArchSpec ObjectFileELF::GetArchitecture() {
   if (!ParseHeader())
     return ArchSpec();
@@ -3744,24 +3664,7 @@ llvm::ArrayRef<ELFProgramHeader> ObjectFileELF::ProgramHeaders() {
 }
 
 DataExtractor ObjectFileELF::GetSegmentData(const ELFProgramHeader &H) {
-  // Try and read the program header from our cached m_data which can come from
-  // the file on disk being mmap'ed or from the initial part of the ELF file we
-  // read from memory and cached.
-  DataExtractor data = DataExtractor(m_data, H.p_offset, H.p_filesz);
-  if (data.GetByteSize() == H.p_filesz)
-    return data;
-  if (IsInMemory()) {
-    // We have a ELF file in process memory, read the program header data from
-    // the process.
-    if (ProcessSP process_sp = m_process_wp.lock()) {
-      const lldb::offset_t base_file_addr = GetBaseAddress().GetFileAddress();
-      const addr_t load_bias = m_memory_addr - base_file_addr;
-      const addr_t data_addr = H.p_vaddr + load_bias;
-      if (DataBufferSP data_sp = ReadMemory(process_sp, data_addr, H.p_memsz))
-        return DataExtractor(data_sp, GetByteOrder(), GetAddressByteSize());
-    }
-  }
-  return DataExtractor();
+  return DataExtractor(m_data, H.p_offset, H.p_filesz);
 }
 
 bool ObjectFileELF::AnySegmentHasPhysicalAddress() {
@@ -3801,88 +3704,3 @@ ObjectFileELF::MapFileDataWritable(const FileSpec &file, uint64_t Size,
   return FileSystem::Instance().CreateWritableDataBuffer(file.GetPath(), Size,
                                                          Offset);
 }
-
-std::optional<DataExtractor> ObjectFileELF::GetDynstrData() {
-  if (SectionList *section_list = GetSectionList()) {
-    // Find the SHT_DYNAMIC section.
-    if (Section *dynamic =
-            section_list
-                ->FindSectionByType(eSectionTypeELFDynamicLinkInfo, true)
-                .get()) {
-      assert(dynamic->GetObjectFile() == this);
-      if (const ELFSectionHeaderInfo *header =
-              GetSectionHeaderByIndex(dynamic->GetID())) {
-        // sh_link: section header index of string table used by entries in
-        // the section.
-        if (Section *dynstr =
-                section_list->FindSectionByID(header->sh_link).get()) {
-          DataExtractor data;
-          if (ReadSectionData(dynstr, data))
-            return data;
-        }
-      }
-    }
-  }
-
-  // Every ELF file which represents an executable or shared library has
-  // mandatory .dynamic entries. Two of these values are DT_STRTAB and DT_STRSZ
-  // and represent the dynamic symbol tables's string table. These are needed
-  // by the dynamic loader and we can read them from a process' address space.
-  //
-  // When loading and ELF file from memory, only the program headers end up
-  // being mapped into memory, and we can find these values in the PT_DYNAMIC
-  // segment.
-  const ELFDynamic *strtab = FindDynamicSymbol(DT_STRTAB);
-  const ELFDynamic *strsz = FindDynamicSymbol(DT_STRSZ);
-  if (strtab == nullptr || strsz == nullptr)
-    return std::nullopt;
-
-  if (ProcessSP process_sp = m_process_wp.lock()) {
-    if (DataBufferSP data_sp =
-            ReadMemory(process_sp, strtab->d_ptr, strsz->d_val))
-      return DataExtractor(data_sp, GetByteOrder(), GetAddressByteSize());
-  } else {
-    // We have an ELF file with no section headers or we didn't find the
-    // .dynamic section. Try and find the .dynstr section.
-    Address addr;
-    if (addr.ResolveAddressUsingFileSections(strtab->d_ptr, GetSectionList())) {
-      DataExtractor data;
-      addr.GetSection()->GetSectionData(data);
-      return DataExtractor(data,
-                           strtab->d_ptr - addr.GetSection()->GetFileAddress(),
-                           strsz->d_val);
-    }
-  }
-  return std::nullopt;
-}
-
-std::optional<lldb_private::DataExtractor> ObjectFileELF::GetDynamicData() {
-  DataExtractor data;
-  // The PT_DYNAMIC program header describes where the .dynamic section is and
-  // doesn't require parsing section headers. The PT_DYNAMIC is required by
-  // executables and shared libraries so it will always be available.
-  for (const ELFProgramHeader &H : ProgramHeaders()) {
-    if (H.p_type == llvm::ELF::PT_DYNAMIC) {
-      data = GetSegmentData(H);
-      if (data.GetByteSize() > 0) {
-        m_dynamic_base_addr = H.p_vaddr;
-        return data;
-      }
-    }
-  }
-  // Fall back to using section headers.
-  if (SectionList *section_list = GetSectionList()) {
-    // Find the SHT_DYNAMIC section.
-    if (Section *dynamic =
-            section_list
-                ->FindSectionByType(eSectionTypeELFDynamicLinkInfo, true)
-                .get()) {
-      assert(dynamic->GetObjectFile() == this);
-      if (ReadSectionData(dynamic, data)) {
-        m_dynamic_base_addr = dynamic->GetFileAddress();
-        return data;
-      }
-    }
-  }
-  return std::nullopt;
-}