Read and store gnu build id from loaded core file (#92078)

As we have debuginfod as symbol locator available in lldb now, we want
to make full use of it.
In case of post mortem debugging, we don't always have the main
executable available.
However, the .note.gnu.build-id of the main executable(some other
modules too), should be available in the core file, as those binaries
are loaded in memory and dumped in the core file.

We try to iterate through the NT_FILE entries, read and store the gnu
build id if possible. This will be very useful as this id is the unique
key which is needed for querying the debuginfod server.

Test:
Build and run lldb. Breakpoint set to
https://github.com/llvm/llvm-project/blob/main/lldb/source/Plugins/SymbolLocator/Debuginfod/SymbolLocatorDebuginfod.cpp#L147
Verified after this commit, module_uuid is the correct gnu build id of
the main executable which caused the crash(first in the NT_FILE entry)

1 files changed, 2 insertions, 59 deletions

diff --git a/lldb/source/Commands/CommandObjectMemory.cpp b/lldb/source/Commands/CommandObjectMemory.cpp
index b78a049..1c13484 100644
--- a/lldb/source/Commands/CommandObjectMemory.cpp
+++ b/lldb/source/Commands/CommandObjectMemory.cpp
@@ -977,35 +977,6 @@ public:
   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
@@ -1106,8 +1077,8 @@ protected:
     found_location = low_addr;
     bool ever_found = false;
     while (count) {
-      found_location = FastSearch(found_location, high_addr, buffer.GetBytes(),
-                                  buffer.GetByteSize());
+      found_location = process->FindInMemory(
+          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");
@@ -1144,34 +1115,6 @@ protected:
     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;