[lld] r295102 - Relax the restriction on what relocations can be in a non-alloc section.

[Rafael Espindola via llvm-commits]

Author: rafael
Date: Tue Feb 14 14:14:03 2017
New Revision: 295102

URL: http://llvm.org/viewvc/llvm-project?rev=295102&view=rev
Log:
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.

Added:
    lld/trunk/test/ELF/i386-reloc-non-alloc.s
Modified:
    lld/trunk/ELF/InputSection.cpp

Modified: lld/trunk/ELF/InputSection.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=295102&r1=295101&r2=295102&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.cpp (original)
+++ lld/trunk/ELF/InputSection.cpp Tue Feb 14 14:14:03 2017
@@ -452,7 +452,8 @@ void InputSection<ELFT>::relocateNonAllo
       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>::relocateNonAllo
     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);
   }
 }

Added: lld/trunk/test/ELF/i386-reloc-non-alloc.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/i386-reloc-non-alloc.s?rev=295102&view=auto
==============================================================================
--- lld/trunk/test/ELF/i386-reloc-non-alloc.s (added)
+++ lld/trunk/test/ELF/i386-reloc-non-alloc.s Tue Feb 14 14:14:03 2017
@@ -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 - .