Revert "[lldb][Mach-O] Don't read symbol table of specially marked binary (#129967)"

This reverts commit 397696b.

This breaks the macOS CI bots, I need to use $LDFLAGS in the $LD
invocation when building the dylib to get the dylibs to build on
the CI bots.  But I've added "-lno-nlists -lhas-nlists" to the LDFLAGS
for the main binary in the same directory, so using LDFLAGS will
result in a compile error for the dylibs.  I'll need to build the
dylibs in a subdir with a different Makefile, will reland with that
change in a bit.

Author: jasonmolenda

lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp

@@ -918,11 +918,6 @@ ConstString ObjectFileMachO::GetSectionNameEHFrame() {
   return g_section_name_eh_frame;
 }
 
-ConstString ObjectFileMachO::GetSectionNameLLDBNoNlist() {
-  static ConstString g_section_name_lldb_no_nlist("__lldb_no_nlist");
-  return g_section_name_lldb_no_nlist;
-}
-
 bool ObjectFileMachO::MagicBytesMatch(DataBufferSP data_sp,
                                       lldb::addr_t data_offset,
                                       lldb::addr_t data_length) {
@@ -2399,54 +2394,15 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
   uint32_t memory_module_load_level = eMemoryModuleLoadLevelComplete;
   bool is_shared_cache_image = IsSharedCacheBinary();
   bool is_local_shared_cache_image = is_shared_cache_image && !IsInMemory();
-
-  ConstString g_segment_name_TEXT = GetSegmentNameTEXT();
-  ConstString g_segment_name_DATA = GetSegmentNameDATA();
-  ConstString g_segment_name_DATA_DIRTY = GetSegmentNameDATA_DIRTY();
-  ConstString g_segment_name_DATA_CONST = GetSegmentNameDATA_CONST();
-  ConstString g_segment_name_OBJC = GetSegmentNameOBJC();
-  ConstString g_section_name_eh_frame = GetSectionNameEHFrame();
-  ConstString g_section_name_lldb_no_nlist = GetSectionNameLLDBNoNlist();
-  SectionSP text_section_sp(
-      section_list->FindSectionByName(g_segment_name_TEXT));
-  SectionSP data_section_sp(
-      section_list->FindSectionByName(g_segment_name_DATA));
   SectionSP linkedit_section_sp(
       section_list->FindSectionByName(GetSegmentNameLINKEDIT()));
-  SectionSP data_dirty_section_sp(
-      section_list->FindSectionByName(g_segment_name_DATA_DIRTY));
-  SectionSP data_const_section_sp(
-      section_list->FindSectionByName(g_segment_name_DATA_CONST));
-  SectionSP objc_section_sp(
-      section_list->FindSectionByName(g_segment_name_OBJC));
-  SectionSP eh_frame_section_sp;
-  SectionSP lldb_no_nlist_section_sp;
-  if (text_section_sp.get()) {
-    eh_frame_section_sp = text_section_sp->GetChildren().FindSectionByName(
-        g_section_name_eh_frame);
-    lldb_no_nlist_section_sp = text_section_sp->GetChildren().FindSectionByName(
-        g_section_name_lldb_no_nlist);
-  } else {
-    eh_frame_section_sp =
-        section_list->FindSectionByName(g_section_name_eh_frame);
-    lldb_no_nlist_section_sp =
-        section_list->FindSectionByName(g_section_name_lldb_no_nlist);
-  }
 
   if (process && m_header.filetype != llvm::MachO::MH_OBJECT &&
       !is_local_shared_cache_image) {
     Target &target = process->GetTarget();
 
     memory_module_load_level = target.GetMemoryModuleLoadLevel();
 
-    // If __TEXT,__lldb_no_nlist section is present in this binary,
-    // and we're reading it out of memory, do not read any of the
-    // nlist entries.  They are not needed in lldb and it may be
-    // expensive to load these.  This is to handle a dylib consisting
-    // of only metadata, no code, but it has many nlist entries.
-    if (lldb_no_nlist_section_sp)
-      memory_module_load_level = eMemoryModuleLoadLevelMinimal;
-
     // Reading mach file from memory in a process or core file...
 
     if (linkedit_section_sp) {
@@ -2570,6 +2526,30 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
 
   const bool have_strtab_data = strtab_data.GetByteSize() > 0;
 
+  ConstString g_segment_name_TEXT = GetSegmentNameTEXT();
+  ConstString g_segment_name_DATA = GetSegmentNameDATA();
+  ConstString g_segment_name_DATA_DIRTY = GetSegmentNameDATA_DIRTY();
+  ConstString g_segment_name_DATA_CONST = GetSegmentNameDATA_CONST();
+  ConstString g_segment_name_OBJC = GetSegmentNameOBJC();
+  ConstString g_section_name_eh_frame = GetSectionNameEHFrame();
+  SectionSP text_section_sp(
+      section_list->FindSectionByName(g_segment_name_TEXT));
+  SectionSP data_section_sp(
+      section_list->FindSectionByName(g_segment_name_DATA));
+  SectionSP data_dirty_section_sp(
+      section_list->FindSectionByName(g_segment_name_DATA_DIRTY));
+  SectionSP data_const_section_sp(
+      section_list->FindSectionByName(g_segment_name_DATA_CONST));
+  SectionSP objc_section_sp(
+      section_list->FindSectionByName(g_segment_name_OBJC));
+  SectionSP eh_frame_section_sp;
+  if (text_section_sp.get())
+    eh_frame_section_sp = text_section_sp->GetChildren().FindSectionByName(
+        g_section_name_eh_frame);
+  else
+    eh_frame_section_sp =
+        section_list->FindSectionByName(g_section_name_eh_frame);
+
   const bool is_arm = (m_header.cputype == llvm::MachO::CPU_TYPE_ARM);
   const bool always_thumb = GetArchitecture().IsAlwaysThumbInstructions();
 

lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.h

@@ -286,7 +286,6 @@ class ObjectFileMachO : public lldb_private::ObjectFile {
   static lldb_private::ConstString GetSegmentNameDWARF();
   static lldb_private::ConstString GetSegmentNameLLVM_COV();
   static lldb_private::ConstString GetSectionNameEHFrame();
-  static lldb_private::ConstString GetSectionNameLLDBNoNlist();
 
   llvm::MachO::dysymtab_command m_dysymtab;
   std::vector<llvm::MachO::section_64> m_mach_sections;