Revert "Read and store gnu build id from loaded core file"

[GeorgeHuyubo]

Reverts #92078

[llvmbot]

@llvm/pr-subscribers-lldb

Author: None (GeorgeHuyubo)

Changes

Reverts llvm/llvm-project#92078

---

Full diff: https://github.com/llvm/llvm-project/pull/92181.diff

5 Files Affected:

• (modified) lldb/include/lldb/Target/Process.h (-50)
• (modified) lldb/source/Commands/CommandObjectMemory.cpp (+59-2)
• (modified) lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp (-50)
• (modified) lldb/source/Plugins/Process/elf-core/ProcessElfCore.h (-11)
• (modified) lldb/source/Target/Process.cpp (-27)

diff --git a/lldb/include/lldb/Target/Process.h b/lldb/include/lldb/Target/Process.h
index c8a49edc5c78d..aac0cf51680a9 100644
--- a/lldb/include/lldb/Target/Process.h
+++ b/lldb/include/lldb/Target/Process.h
@@ -406,36 +406,6 @@ class Process : public std::enable_shared_from_this<Process>,
                                   lldb::StateType state);
   } Notifications;
 
-  class ProcessMemoryIterator {
-  public:
-    ProcessMemoryIterator(lldb::ProcessSP process_sp, lldb::addr_t base)
-        : m_process_sp(process_sp), m_base_addr(base) {
-      lldbassert(process_sp.get() != nullptr);
-    }
-
-    bool IsValid() { return m_is_valid; }
-
-    uint8_t operator[](lldb::addr_t offset) {
-      if (!IsValid())
-        return 0;
-
-      uint8_t retval = 0;
-      Status error;
-      if (0 ==
-          m_process_sp->ReadMemory(m_base_addr + offset, &retval, 1, error)) {
-        m_is_valid = false;
-        return 0;
-      }
-
-      return retval;
-    }
-
-  private:
-    lldb::ProcessSP m_process_sp;
-    lldb::addr_t m_base_addr;
-    bool m_is_valid = true;
-  };
-
   class ProcessEventData : public EventData {
     friend class Process;
 
@@ -1679,26 +1649,6 @@ class Process : public std::enable_shared_from_this<Process>,
 
   lldb::addr_t ReadPointerFromMemory(lldb::addr_t vm_addr, Status &error);
 
-  /// Find a string within a memory region.
-  ///
-  /// This function searches for the string represented by the provided buffer
-  /// within the memory range specified by the low and high addresses. It uses
-  /// a bad character heuristic to optimize the search process.
-  ///
-  /// \param[in] low The starting address of the memory region to be searched.
-  ///
-  /// \param[in] high The ending address of the memory region to be searched.
-  ///
-  /// \param[in] buffer A pointer to the buffer containing the string to be
-  /// searched.
-  ///
-  /// \param[in] buffer_size The size of the buffer in bytes.
-  ///
-  /// \return The address where the string was found or LLDB_INVALID_ADDRESS if
-  /// not found.
-  lldb::addr_t FindInMemory(lldb::addr_t low, lldb::addr_t high,
-                            uint8_t *buffer, size_t buffer_size);
-
   bool WritePointerToMemory(lldb::addr_t vm_addr, lldb::addr_t ptr_value,
                             Status &error);
 
diff --git a/lldb/source/Commands/CommandObjectMemory.cpp b/lldb/source/Commands/CommandObjectMemory.cpp
index 1c13484dede64..b78a0492cca55 100644
--- a/lldb/source/Commands/CommandObjectMemory.cpp
+++ b/lldb/source/Commands/CommandObjectMemory.cpp
@@ -977,6 +977,35 @@ class CommandObjectMemoryFind : public CommandObjectParsed {
   Options *GetOptions() override { return &m_option_group; }
 
 protected:
+  class ProcessMemoryIterator {
+  public:
+    ProcessMemoryIterator(ProcessSP process_sp, lldb::addr_t base)
+        : m_process_sp(process_sp), m_base_addr(base) {
+      lldbassert(process_sp.get() != nullptr);
+    }
+
+    bool IsValid() { return m_is_valid; }
+
+    uint8_t operator[](lldb::addr_t offset) {
+      if (!IsValid())
+        return 0;
+
+      uint8_t retval = 0;
+      Status error;
+      if (0 ==
+          m_process_sp->ReadMemory(m_base_addr + offset, &retval, 1, error)) {
+        m_is_valid = false;
+        return 0;
+      }
+
+      return retval;
+    }
+
+  private:
+    ProcessSP m_process_sp;
+    lldb::addr_t m_base_addr;
+    bool m_is_valid = true;
+  };
   void DoExecute(Args &command, CommandReturnObject &result) override {
     // No need to check "process" for validity as eCommandRequiresProcess
     // ensures it is valid
@@ -1077,8 +1106,8 @@ class CommandObjectMemoryFind : public CommandObjectParsed {
     found_location = low_addr;
     bool ever_found = false;
     while (count) {
-      found_location = process->FindInMemory(
-          found_location, high_addr, buffer.GetBytes(), buffer.GetByteSize());
+      found_location = FastSearch(found_location, high_addr, buffer.GetBytes(),
+                                  buffer.GetByteSize());
       if (found_location == LLDB_INVALID_ADDRESS) {
         if (!ever_found) {
           result.AppendMessage("data not found within the range.\n");
@@ -1115,6 +1144,34 @@ class CommandObjectMemoryFind : public CommandObjectParsed {
     result.SetStatus(lldb::eReturnStatusSuccessFinishResult);
   }
 
+  lldb::addr_t FastSearch(lldb::addr_t low, lldb::addr_t high, uint8_t *buffer,
+                          size_t buffer_size) {
+    const size_t region_size = high - low;
+
+    if (region_size < buffer_size)
+      return LLDB_INVALID_ADDRESS;
+
+    std::vector<size_t> bad_char_heuristic(256, buffer_size);
+    ProcessSP process_sp = m_exe_ctx.GetProcessSP();
+    ProcessMemoryIterator iterator(process_sp, low);
+
+    for (size_t idx = 0; idx < buffer_size - 1; idx++) {
+      decltype(bad_char_heuristic)::size_type bcu_idx = buffer[idx];
+      bad_char_heuristic[bcu_idx] = buffer_size - idx - 1;
+    }
+    for (size_t s = 0; s <= (region_size - buffer_size);) {
+      int64_t j = buffer_size - 1;
+      while (j >= 0 && buffer[j] == iterator[s + j])
+        j--;
+      if (j < 0)
+        return low + s;
+      else
+        s += bad_char_heuristic[iterator[s + buffer_size - 1]];
+    }
+
+    return LLDB_INVALID_ADDRESS;
+  }
+
   OptionGroupOptions m_option_group;
   OptionGroupFindMemory m_memory_options;
   OptionGroupMemoryTag m_memory_tag_options;
diff --git a/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp b/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp
index 4ff03eb8ab485..36812c27a5b6d 100644
--- a/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp
+++ b/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp
@@ -6,12 +6,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include <cstddef>
 #include <cstdlib>
 
 #include <memory>
 #include <mutex>
-#include <tuple>
 
 #include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleSpec.h"
@@ -212,9 +210,6 @@ Status ProcessElfCore::DoLoadCore() {
     }
   }
 
-  // We need to update uuid after address range is populated.
-  UpdateBuildIdForNTFileEntries();
-
   if (!ranges_are_sorted) {
     m_core_aranges.Sort();
     m_core_range_infos.Sort();
@@ -263,7 +258,6 @@ Status ProcessElfCore::DoLoadCore() {
     if (!m_nt_file_entries.empty()) {
       ModuleSpec exe_module_spec;
       exe_module_spec.GetArchitecture() = arch;
-      exe_module_spec.GetUUID() = m_nt_file_entries[0].uuid;
       exe_module_spec.GetFileSpec().SetFile(m_nt_file_entries[0].path,
                                             FileSpec::Style::native);
       if (exe_module_spec.GetFileSpec()) {
@@ -277,16 +271,6 @@ Status ProcessElfCore::DoLoadCore() {
   return error;
 }
 
-void ProcessElfCore::UpdateBuildIdForNTFileEntries() {
-  if (!m_nt_file_entries.empty()) {
-    for (NT_FILE_Entry &entry : m_nt_file_entries) {
-      std::optional<UUID> uuid = FindBuildId(entry);
-      if (uuid)
-        entry.uuid = uuid.value();
-    }
-  }
-}
-
 lldb_private::DynamicLoader *ProcessElfCore::GetDynamicLoader() {
   if (m_dyld_up.get() == nullptr)
     m_dyld_up.reset(DynamicLoader::FindPlugin(
@@ -999,40 +983,6 @@ llvm::Error ProcessElfCore::ParseThreadContextsFromNoteSegment(
   }
 }
 
-bool ProcessElfCore::IsElf(const NT_FILE_Entry entry) {
-  size_t size = strlen(llvm::ELF::ElfMagic);
-  uint8_t buf[size];
-  Status error;
-  size_t byte_read = ReadMemory(entry.start, buf, size, error);
-  if (byte_read == size)
-    return memcmp(llvm::ELF::ElfMagic, buf, size) == 0;
-  else
-    return false;
-}
-
-std::optional<UUID> ProcessElfCore::FindBuildId(const NT_FILE_Entry entry) {
-  if (!IsElf(entry))
-    return std::nullopt;
-  // Build ID is stored in the ELF file as a section named ".note.gnu.build-id"
-  uint8_t gnu_build_id_bytes[8] = {0x03, 0x00, 0x00, 0x00,
-                                   0x47, 0x4e, 0x55, 0x00};
-  lldb::addr_t gnu_build_id_addr =
-      FindInMemory(entry.start, entry.end, gnu_build_id_bytes, 8);
-  if (gnu_build_id_addr == LLDB_INVALID_ADDRESS)
-    return std::nullopt;
-  uint8_t buf[36];
-  Status error;
-  size_t byte_read = ReadMemory(gnu_build_id_addr - 8, buf, 36, error);
-  // .note.gnu.build-id starts with 04 00 00 00 {id_byte_size} 00 00 00 03 00 00
-  // 00 47 4e 55 00
-  if (byte_read == 36) {
-    if (buf[0] == 0x04) {
-      return UUID(llvm::ArrayRef<uint8_t>(buf + 16, buf[4] /*byte size*/));
-    }
-  }
-  return std::nullopt;
-}
-
 uint32_t ProcessElfCore::GetNumThreadContexts() {
   if (!m_thread_data_valid)
     DoLoadCore();
diff --git a/lldb/source/Plugins/Process/elf-core/ProcessElfCore.h b/lldb/source/Plugins/Process/elf-core/ProcessElfCore.h
index ae827f3df002c..2cec635bbacfe 100644
--- a/lldb/source/Plugins/Process/elf-core/ProcessElfCore.h
+++ b/lldb/source/Plugins/Process/elf-core/ProcessElfCore.h
@@ -117,8 +117,6 @@ class ProcessElfCore : public lldb_private::PostMortemProcess {
     lldb::addr_t end;
     lldb::addr_t file_ofs;
     std::string path;
-    lldb_private::UUID
-        uuid; // extracted from .note.gnu.build-id section from core file
   };
 
   // For ProcessElfCore only
@@ -160,15 +158,6 @@ class ProcessElfCore : public lldb_private::PostMortemProcess {
   // Returns number of thread contexts stored in the core file
   uint32_t GetNumThreadContexts();
 
-  // Populate gnu uuid for each NT_FILE entry
-  void UpdateBuildIdForNTFileEntries();
-
-  // Returns the UUID of a given NT_FILE entry
-  std::optional<lldb_private::UUID> FindBuildId(const NT_FILE_Entry entry);
-
-  // Returns true if the given NT_FILE entry is an ELF file
-  bool IsElf(const NT_FILE_Entry entry);
-
   // Parse a contiguous address range of the process from LOAD segment
   lldb::addr_t
   AddAddressRangeFromLoadSegment(const elf::ELFProgramHeader &header);
diff --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index 6f5c43bc41082..25afade9a8275 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -3191,33 +3191,6 @@ Status Process::Halt(bool clear_thread_plans, bool use_run_lock) {
   return Status();
 }
 
-lldb::addr_t Process::FindInMemory(lldb::addr_t low, lldb::addr_t high,
-                                   uint8_t *buffer, size_t buffer_size) {
-  const size_t region_size = high - low;
-
-  if (region_size < buffer_size)
-    return LLDB_INVALID_ADDRESS;
-
-  std::vector<size_t> bad_char_heuristic(256, buffer_size);
-  ProcessMemoryIterator iterator(shared_from_this(), low);
-
-  for (size_t idx = 0; idx < buffer_size - 1; idx++) {
-    decltype(bad_char_heuristic)::size_type bcu_idx = buffer[idx];
-    bad_char_heuristic[bcu_idx] = buffer_size - idx - 1;
-  }
-  for (size_t s = 0; s <= (region_size - buffer_size);) {
-    int64_t j = buffer_size - 1;
-    while (j >= 0 && buffer[j] == iterator[s + j])
-      j--;
-    if (j < 0)
-      return low + s;
-    else
-      s += bad_char_heuristic[iterator[s + buffer_size - 1]];
-  }
-
-  return LLDB_INVALID_ADDRESS;
-}
-
 Status Process::StopForDestroyOrDetach(lldb::EventSP &exit_event_sp) {
   Status error;