[PATCH] D29170: [ELF] - Remove unnessesary checks from GC logic.

[George Rimar via Phabricator via llvm-commits]

grimar updated this revision to Diff 85943.
grimar added a comment.

- Addressed review comment.


https://reviews.llvm.org/D29170

Files:
  ELF/InputSection.cpp
  ELF/InputSection.h
  ELF/MarkLive.cpp


Index: ELF/MarkLive.cpp
===================================================================
--- ELF/MarkLive.cpp
+++ ELF/MarkLive.cpp
@@ -156,20 +156,16 @@
     scanEhFrameSection(EH, EH.rels(), Enqueue);
 }
 
-// We do not garbage-collect two types of sections:
-// 1) Sections used by the loader (.init, .fini, .ctors, .dtors or .jcr)
-// 2) Non-allocatable sections which typically contain debugging information
+// We do not garbage-collect sections used by the loader (.init, .fini, .ctors,
+// .dtors or .jcr)
 template <class ELFT> static bool isReserved(InputSectionBase<ELFT> *Sec) {
   switch (Sec->Type) {
   case SHT_FINI_ARRAY:
   case SHT_INIT_ARRAY:
   case SHT_NOTE:
   case SHT_PREINIT_ARRAY:
     return true;
   default:
-    if (!(Sec->Flags & SHF_ALLOC))
-      return true;
-
     // We do not want to reclaim sections if they can be referred
     // by __start_* and __stop_* symbols.
     StringRef S = Sec->Name;
@@ -196,10 +192,6 @@
     if (!R.Sec || R.Sec == &InputSection<ELFT>::Discarded)
       return;
 
-    // We don't gc non alloc sections.
-    if (!(R.Sec->Flags & SHF_ALLOC))
-      return;
-
     // Usually, a whole section is marked as live or dead, but in mergeable
     // (splittable) sections, each piece of data has independent liveness bit.
     // So we explicitly tell it which offset is in use.
@@ -240,7 +232,7 @@
     // referred by .eh_frame here.
     if (auto *EH = dyn_cast_or_null<EhInputSection<ELFT>>(Sec))
       scanEhFrameSection<ELFT>(*EH, Enqueue);
-    if (isReserved(Sec) || Script<ELFT>::X->shouldKeep(Sec))
+    if (Sec->Live || isReserved(Sec) || Script<ELFT>::X->shouldKeep(Sec))
       Enqueue({Sec, 0});
   }
 
Index: ELF/InputSection.h
===================================================================
--- ELF/InputSection.h
+++ ELF/InputSection.h
@@ -174,9 +174,10 @@
   void splitIntoPieces();
 
   // Mark the piece at a given offset live. Used by GC.
+  // We always keep whole non-alloc sections (usually debug ones).
   void markLiveAt(uintX_t Offset) {
-    assert(this->Flags & llvm::ELF::SHF_ALLOC);
-    LiveOffsets.insert(Offset);
+    if (this->Flags & SHF_ALLOC)
+      LiveOffsets.insert(Offset);
   }
 
   // Translate an offset in the input section to an offset
Index: ELF/InputSection.cpp
===================================================================
--- ELF/InputSection.cpp
+++ ELF/InputSection.cpp
@@ -57,6 +57,8 @@
                                          uint32_t Info, uintX_t Addralign,
                                          ArrayRef<uint8_t> Data, StringRef Name,
                                          Kind SectionKind)
+    // We do not GC non-allocatable sections which typically contain debugging
+    // information, so set Live flag for them.
     : InputSectionData(SectionKind, Name, Data,
                        !Config->GcSections || !(Flags & SHF_ALLOC)),
       File(File), Flags(Flags), Entsize(Entsize), Type(Type), Link(Link),


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