diff --git a/lld/ELF/InputFiles.h b/lld/ELF/InputFiles.h
--- a/lld/ELF/InputFiles.h
+++ b/lld/ELF/InputFiles.h
@@ -234,8 +234,10 @@
   // but had one or more functions with the no_split_stack attribute.
   bool SomeNoSplitStack = false;
 
-  // True if the file has any live Regular or Merge sections that aren't
-  // the LDSA section.
+  // True if the garbage-collector marks at least one "real" section,
+  // e.g. a code or data section except a exception handler table.
+  // If false, we discard debug sections of this file because we know
+  // all sections described by the debug sections are dead.
   bool HasLiveCodeOrData = false;
 
   // Pointer to this input file's .llvm_addrsig section, if it has one.
diff --git a/lld/ELF/MarkLive.cpp b/lld/ELF/MarkLive.cpp
--- a/lld/ELF/MarkLive.cpp
+++ b/lld/ELF/MarkLive.cpp
@@ -184,19 +184,19 @@
   if (auto *MS = dyn_cast<MergeInputSection>(Sec))
     MS->getSectionPiece(Offset)->Live = true;
 
-  InputSection *S = dyn_cast<InputSection>(Sec);
   // LSDA does not count as "live code or data" in the object file.
   // The section may already have been marked live for LSDA in which
   // case we still need to mark the file.
-  if (S && !IsLSDA && Sec->File)
+  if (Sec->File && !IsLSDA)
     Sec->getFile<ELFT>()->HasLiveCodeOrData = true;
 
   if (Sec->Live)
     return;
 
   Sec->Live = true;
+
   // Add input section to the queue.
-  if (S)
+  if (InputSection *S = dyn_cast<InputSection>(Sec))
     Queue.push_back(S);
 }
 
@@ -288,44 +288,53 @@
     return;
   }
 
-  // Otheriwse, do mark-sweep GC.
-  //
-  // The -gc-sections option works only for SHF_ALLOC sections
-  // (sections that are memory-mapped at runtime). So we can
-  // unconditionally make non-SHF_ALLOC sections alive except
-  // SHF_LINK_ORDER and SHT_REL/SHT_RELA sections and .debug sections.
+  // Otheriwse, do mark-sweep GC. Follow the graph to mark all live
+  // sections.
+  MarkLive<ELFT>().run();
+
+  // Usually, non-SHF_ALLOC sections are not garbage-collected even if
+  // they are unreachable. It's because reachability is not a good
+  // signal whether they are garbage or not. Here are a few examples:
   //
-  // Usually, SHF_ALLOC sections are not removed even if they are
-  // unreachable through relocations because reachability is not
-  // a good signal whether they are garbage or not (e.g. there is
-  // usually no section referring to a .comment section, but we
-  // want to keep it.).
+  //  - A .comment section contains some ASCII text. There is usually no
+  //    section referring from/to a .comment section, but we want to
+  //    keep it to not surprise users.
   //
-  // Note on SHF_LINK_ORDER: Such sections contain metadata and they
-  // have a reverse dependency on the InputSection they are linked with.
-  // We are able to garbage collect them.
+  //  - An object file usually contains only one .debug section
+  //    describing all functions and data in the same object file, even
+  //    if the object file is compiled with -f{function,data}-sections.
+  //    There is no relocation from code/data sections to a debug
+  //    section, but a debug section contains lots of relocations to
+  //    code/data sections (so this is a reverse dependency). If at
+  //    least one code/data is live, we want to keep the entire debug
+  //    info.
   //
-  // Note on SHF_REL{,A}: Such sections reach here only when -r
-  // or -emit-reloc were given. And they are subject of garbage
-  // collection because, if we remove a text section, we also
-  // remove its relocation section.
+  // Here, we mark non-SHF_ALLOC sections.
   for (InputSectionBase *Sec : InputSections) {
-    bool IsAlloc = (Sec->Flags & SHF_ALLOC);
-    bool IsLinkOrder = (Sec->Flags & SHF_LINK_ORDER);
-    bool IsRel = (Sec->Type == SHT_REL || Sec->Type == SHT_RELA);
+    if (Sec->Flags & SHF_ALLOC)
+      continue;
 
-    if (!IsAlloc && !IsLinkOrder && !IsRel && !Sec->Debug)
-      Sec->Live = true;
-  }
+    // If a file does not contain any live code nor data, we want to
+    // discard debug sections as they are completely useless.
+    if (Sec->File && !Sec->getFile<ELFT>()->HasLiveCodeOrData &&
+        Sec->Debug)
+      continue;
 
-  // Follow the graph to mark all live sections.
-  MarkLive<ELFT>().run();
+    // SHF_LINK_ORDER sections contain metadata and they have a
+    // reverse dependency on the InputSection they are linked with.
+    // We are able to garbage collect them.
+    if (Sec->Flags & SHF_LINK_ORDER)
+      continue;
 
-  // Mark debug sections as live in any object file that has a live
-  // Regular or Merge section.
-  for (InputSectionBase *Sec : InputSections)
-    if (Sec->Debug && Sec->getFile<ELFT>()->HasLiveCodeOrData)
-      Sec->Live = true;
+    // SHT_REL sections sections reach here only when -r or
+    // -emit-reloc were given. And they are subject of garbage
+    // collection because, if we remove a text section, we also
+    // remove its relocation section.
+    if (Sec->Type == SHT_REL || Sec->Type == SHT_RELA)
+      continue;
+
+    Sec->Live = true;
+  }
 
   // Report garbage-collected sections.
   if (Config->PrintGcSections)