[PATCH] D18166: Add _GLOBAL_OFFSET_TABLE_ symbol to shared libraries

Davide Italiano via llvm-commits llvm-commits at lists.llvm.org
Tue Mar 15 15:30:09 PDT 2016


This revision was automatically updated to reflect the committed changes.
Closed by commit rL263594: [ELF] Ignore _GLOBAL_OFFSET_TABLE_ symbol in shared libs. (authored by davide).

Changed prior to commit:
  http://reviews.llvm.org/D18166?vs=50751&id=50777#toc

Repository:
  rL LLVM

http://reviews.llvm.org/D18166

Files:
  lld/trunk/ELF/Driver.cpp
  lld/trunk/test/ELF/global_offset_table_shared.s

Index: lld/trunk/test/ELF/global_offset_table_shared.s
===================================================================
--- lld/trunk/test/ELF/global_offset_table_shared.s
+++ lld/trunk/test/ELF/global_offset_table_shared.s
@@ -0,0 +1,6 @@
+// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t
+// RUN: ld.lld -shared %t -o %t2
+// RUN: llvm-readobj -t %t2 | Filecheck %s
+.long _GLOBAL_OFFSET_TABLE_
+
+// CHECK-NOT: Name: _GLOBAL_OFFSET_TABLE_
Index: lld/trunk/ELF/Driver.cpp
===================================================================
--- lld/trunk/ELF/Driver.cpp
+++ lld/trunk/ELF/Driver.cpp
@@ -343,14 +343,15 @@
 
   Config->Rela = ELFT::Is64Bits;
 
-  if (!Config->Shared && !Config->Relocatable) {
+  if (Config->Entry.empty() && !Config->Shared && !Config->Relocatable &&
+      Config->EMachine != EM_AMDGPU)
     // Add entry symbol.
     //
     // There is no entry symbol for AMDGPU binaries, so skip adding one to avoid
     // having and undefined symbol.
-    if (Config->Entry.empty() && Config->EMachine != EM_AMDGPU)
-      Config->Entry = (Config->EMachine == EM_MIPS) ? "__start" : "_start";
+    Config->Entry = Config->EMachine == EM_MIPS ? "__start" : "_start";
 
+  if (!Config->Relocatable)
     // In the assembly for 32 bit x86 the _GLOBAL_OFFSET_TABLE_ symbol
     // is magical and is used to produce a R_386_GOTPC relocation.
     // The R_386_GOTPC relocation value doesn't actually depend on the
@@ -364,7 +365,6 @@
     // Given that the symbol is effectively unused, we just create a dummy
     // hidden one to avoid the undefined symbol error.
     Symtab.addIgnored("_GLOBAL_OFFSET_TABLE_");
-  }
 
   if (!Config->Entry.empty()) {
     // Set either EntryAddr (if S is a number) or EntrySym (otherwise).


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