[PATCH] D37623: [ELF] - Simplify removeUnusedSyntheticSections a bit.

[George Rimar via Phabricator via llvm-commits]

grimar created this revision.
Herald added subscribers: arichardson, sdardis, emaste.

Previously`InX::Got` and `InX::MipsGot` synthetic sections
were not removed if `ElfSym::GlobalOffsetTable` was defined.
`ElfSym::GlobalOffsetTable` is a symbol for `_GLOBAL_OFFSET_TABLE_`.

Patch moves `ElfSym::GlobalOffsetTable` check out from `removeUnusedSyntheticSections`.
Also note that there was no point to check `ElfSym::GlobalOffsetTable` for MIPS case
because `InX::MipsGot::empty()` always returns false for non-relocatable case, and in case
of relocatable output we do not create special symbols anyways.


https://reviews.llvm.org/D37623

Files:
  ELF/SyntheticSections.cpp
  ELF/Writer.cpp


Index: ELF/Writer.cpp
===================================================================
--- ELF/Writer.cpp
+++ ELF/Writer.cpp
@@ -1198,8 +1198,6 @@
     OutputSection *OS = SS->getParent();
     if (!SS->empty() || !OS)
       continue;
-    if ((SS == InX::Got || SS == InX::MipsGot) && ElfSym::GlobalOffsetTable)
-      continue;
 
     std::vector<BaseCommand *>::iterator Empty = OS->Commands.end();
     for (auto I = OS->Commands.begin(), E = OS->Commands.end(); I != E; ++I) {
Index: ELF/SyntheticSections.cpp
===================================================================
--- ELF/SyntheticSections.cpp
+++ ELF/SyntheticSections.cpp
@@ -665,7 +665,8 @@
 bool GotSection::empty() const {
   // If we have a relocation that is relative to GOT (such as GOTOFFREL),
   // we need to emit a GOT even if it's empty.
-  return NumEntries == 0 && !HasGotOffRel;
+  // Do the same if we have reference to _GLOBAL_OFFSET_TABLE_ symbol.
+  return NumEntries == 0 && !HasGotOffRel && !ElfSym::GlobalOffsetTable;
 }
 
 void GotSection::writeTo(uint8_t *Buf) {


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