From ee29e42b3341e6d14bb55f9ad532941343a89a2f Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Tue, 14 Feb 2017 20:14:03 +0000
Subject: [PATCH] Relax the restriction on what relocations can be in a
 non-alloc section.

The main thing that they can't have is relocations that require the
creation of gots or plt.  For now also accept R_PC.

Found while linking seabios.

llvm-svn: 295102
---
 lld/ELF/InputSection.cpp            |  5 +++--
 lld/test/ELF/i386-reloc-non-alloc.s | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100644 lld/test/ELF/i386-reloc-non-alloc.s

diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
index 9b21a3271902..40f95daaf3d1 100644
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -452,7 +452,8 @@ void InputSection<ELFT>::relocateNonAlloc(uint8_t *Buf, ArrayRef<RelTy> Rels) {
       Addend += Target->getImplicitAddend(BufLoc, Type);
 
     SymbolBody &Sym = this->File->getRelocTargetSym(Rel);
-    if (Target->getRelExpr(Type, Sym) != R_ABS) {
+    RelExpr E = Target->getRelExpr(Type, Sym);
+    if (E != R_ABS && E != R_PC) {
       error(this->getLocation(Offset) + ": has non-ABS reloc");
       return;
     }
@@ -461,7 +462,7 @@ void InputSection<ELFT>::relocateNonAlloc(uint8_t *Buf, ArrayRef<RelTy> Rels) {
     uint64_t SymVA = 0;
     if (!Sym.isTls() || Out<ELFT>::TlsPhdr)
       SymVA = SignExtend64<sizeof(uintX_t) * 8>(
-          getRelocTargetVA<ELFT>(Type, Addend, AddrLoc, Sym, R_ABS));
+          getRelocTargetVA<ELFT>(Type, Addend, AddrLoc, Sym, E));
     Target->relocateOne(BufLoc, Type, SymVA);
   }
 }
diff --git a/lld/test/ELF/i386-reloc-non-alloc.s b/lld/test/ELF/i386-reloc-non-alloc.s
new file mode 100644
index 000000000000..98612fe57f74
--- /dev/null
+++ b/lld/test/ELF/i386-reloc-non-alloc.s
@@ -0,0 +1,18 @@
+// REQUIRES: x86
+
+// RUN: llvm-mc -filetype=obj -triple=i386-pc-linux %s -o %t.o
+// RUN: ld.lld -shared %t.o -o %t.so
+// RUN: llvm-objdump -s %t.so | FileCheck %s
+
+// CHECK:      Contents of section .text:
+// CHECK-NEXT: 1000 00000000 00000000
+
+// CHECK: Contents of section .bar:
+// CHECK-NEXT:  0000 00100000 fc0f0000
+
+foo:
+.quad 0
+
+.section .bar
+.long foo - .
+.long foo - .