[PATCH] D94809: [LLD][ELF][AArch64] Set _GLOBAL_OFFSET_TABLE_ at the start of .got

[Adhemerval Zanella via Phabricator via llvm-commits]

zatrazz created this revision.
zatrazz added reviewers: grimar, peter.smith, ruiu, MaskRay.
Herald added subscribers: danielkiss, kristof.beyls, arichardson, emaste.
Herald added a reviewer: espindola.
zatrazz requested review of this revision.
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The commit 18aa0be36ed9 changed the default GotBaseSymInGotPlt to true
for AArch64.  This is different than binutils, where
_GLOBAL_OFFSET_TABLE_ points at the start or .got instead of .got.plt.

It seems to not intefere with current relocations used by LLVM.  However
as indicated by PR#40357 [1] gcc generates R_AARCH64_LD64_GOTPAGE_LO15
for -pie (in fact it also generated the relocation for -fpic in some
cases).

This change is requires to correctly handle R_AARCH64_LD64_GOTPAGE_LO15
by lld from objects generated by gcc.

[1] https://bugs.llvm.org/show_bug.cgi?id=40357


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D94809

Files:
  lld/ELF/Arch/AArch64.cpp
  lld/test/ELF/global-offset-table-position-aarch64.s


Index: lld/test/ELF/global-offset-table-position-aarch64.s
===================================================================
--- lld/test/ELF/global-offset-table-position-aarch64.s
+++ lld/test/ELF/global-offset-table-position-aarch64.s
@@ -27,4 +27,4 @@
 // CHECK-NEXT:     Other [ (0x2)
 // CHECK-NEXT:       STV_HIDDEN (0x2)
 // CHECK-NEXT:     ]
-// CHECK-NEXT:     Section: .got.plt
+// CHECK-NEXT:     Section: .got
Index: lld/ELF/Arch/AArch64.cpp
===================================================================
--- lld/ELF/Arch/AArch64.cpp
+++ lld/ELF/Arch/AArch64.cpp
@@ -70,6 +70,7 @@
   pltEntrySize = 16;
   ipltEntrySize = 16;
   defaultMaxPageSize = 65536;
+  gotBaseSymInGotPlt = false;
 
   // Align to the 2 MiB page size (known as a superpage or huge page).
   // FreeBSD automatically promotes 2 MiB-aligned allocations.


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