Revert "[lldb] Add support for debugging via the dynamic linker."

This reverts commit 1cbdc07.

Buildbot failure started after this patch with failure in
api/multithreaded/TestMultithreaded.py:
https://lab.llvm.org/buildbot/#/builders/68/builds/17556

lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp

@@ -56,19 +56,6 @@ static addr_t ResolveRendezvousAddress(Process *process) {
                   "%s resolved via direct object file approach to 0x%" PRIx64,
                   __FUNCTION__, info_location);
       } else {
-        const Symbol *_r_debug =
-            target->GetExecutableModule()->FindFirstSymbolWithNameAndType(
-                ConstString("_r_debug"));
-        if (_r_debug) {
-          info_addr = _r_debug->GetAddress().GetLoadAddress(target);
-          if (info_addr != LLDB_INVALID_ADDRESS) {
-            LLDB_LOGF(log,
-                      "%s resolved by finding symbol '_r_debug' whose value is "
-                      "0x%" PRIx64,
-                      __FUNCTION__, info_addr);
-            return info_addr;
-          }
-        }
         LLDB_LOGF(log,
                   "%s FAILED - direct object file approach did not yield a "
                   "valid address",
@@ -289,14 +276,6 @@ bool DYLDRendezvous::FillSOEntryFromModuleInfo(
   entry.base_addr = base_addr;
   entry.dyn_addr = dyn_addr;
 
-  // ld.so saves empty file name for the executable file in the link map.
-  // When executable is run using ld.so, we need to be update executable path.
-  if (name.empty()) {
-    MemoryRegionInfo region;
-    Status region_status =
-        m_process->GetMemoryRegionInfo(entry.dyn_addr, region);
-    name = region.GetName().AsCString();
-  }
   entry.file_spec.SetFile(name, FileSpec::Style::native);
 
   UpdateBaseAddrIfNecessary(entry, name);
@@ -568,15 +547,6 @@ bool DYLDRendezvous::ReadSOEntryFromMemory(lldb::addr_t addr, SOEntry &entry) {
     return false;
 
   std::string file_path = ReadStringFromMemory(entry.path_addr);
-
-  // ld.so saves empty file name for the executable file in the link map.
-  // When executable is run using ld.so, we need to be update executable path.
-  if (file_path.empty()) {
-    MemoryRegionInfo region;
-    Status region_status =
-        m_process->GetMemoryRegionInfo(entry.dyn_addr, region);
-    file_path = region.GetName().AsCString();
-  }
   entry.file_spec.SetFile(file_path, FileSpec::Style::native);
 
   UpdateBaseAddrIfNecessary(entry, file_path);

lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp

@@ -333,48 +333,28 @@ bool DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint() {
     LLDB_LOG(log, "Rendezvous structure is not set up yet. "
                   "Trying to locate rendezvous breakpoint in the interpreter "
                   "by symbol name.");
-    // Function names from different dynamic loaders that are known to be
-    // used as rendezvous between the loader and debuggers.
+    ModuleSP interpreter = LoadInterpreterModule();
+    if (!interpreter) {
+      LLDB_LOG(log, "Can't find interpreter, rendezvous breakpoint isn't set.");
+      return false;
+    }
+
+    // Function names from different dynamic loaders that are known to be used
+    // as rendezvous between the loader and debuggers.
     static std::vector<std::string> DebugStateCandidates{
         "_dl_debug_state", "rtld_db_dlactivity", "__dl_rtld_db_dlactivity",
         "r_debug_state",   "_r_debug_state",     "_rtld_debug_state",
     };
 
-    ModuleSP interpreter = LoadInterpreterModule();
-    if (!interpreter) {
-      if (NameMatches(m_process->GetTarget()
-                          .GetExecutableModulePointer()
-                          ->GetFileSpec()
-                          .GetFilename()
-                          .GetCString(),
-                      NameMatch::StartsWith, "ld-")) {
-        FileSpecList containingModules;
-        containingModules.Append(
-            m_process->GetTarget().GetExecutableModulePointer()->GetFileSpec());
-
-        dyld_break = target.CreateBreakpoint(
-            &containingModules, /*containingSourceFiles=*/nullptr,
-            DebugStateCandidates, eFunctionNameTypeFull, eLanguageTypeC,
-            /*offset=*/0,
-            /*skip_prologue=*/eLazyBoolNo,
-            /*internal=*/true,
-            /*request_hardware=*/false);
-      } else {
-        LLDB_LOG(log,
-                 "Can't find interpreter, rendezvous breakpoint isn't set.");
-        return false;
-      }
-    } else {
-      FileSpecList containingModules;
-      containingModules.Append(interpreter->GetFileSpec());
-      dyld_break = target.CreateBreakpoint(
-          &containingModules, /*containingSourceFiles=*/nullptr,
-          DebugStateCandidates, eFunctionNameTypeFull, eLanguageTypeC,
-          /*offset=*/0,
-          /*skip_prologue=*/eLazyBoolNo,
-          /*internal=*/true,
-          /*request_hardware=*/false);
-    }
+    FileSpecList containingModules;
+    containingModules.Append(interpreter->GetFileSpec());
+    dyld_break = target.CreateBreakpoint(
+        &containingModules, nullptr /* containingSourceFiles */,
+        DebugStateCandidates, eFunctionNameTypeFull, eLanguageTypeC,
+        0,           /* offset */
+        eLazyBoolNo, /* skip_prologue */
+        true,        /* internal */
+        false /* request_hardware */);
   }
 
   if (dyld_break->GetNumResolvedLocations() != 1) {