[ELF} - Don't allow R_X86_64_TPOFF32 dynamic relocation when linking PIC

[grimar]

Summary

Both gold and bfd restrict that one:

ld.bfd: test.o: relocation R_X86_64_TPOFF32 against `var' can not be used when making a shared object; recompile with -fPIC
ld.gold: error: test.o: unsupported reloc 23 against global symbol var

What looks reasonable because it is 32 bit.

[ruiu]

LGTM

lld/trunk/ELF/Target.cpp

void X86_64TargetInfo<ELFT>::writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr,
 
   write32le(Buf + 2, GotPltEntryAddr - PltEntryAddr - 6);
   write32le(Buf + 7, Index);
   write32le(Buf + 12, -Index * PltEntrySize - PltHeaderSize - 16);
 }
 
 template <class ELFT>
 bool X86_64TargetInfo<ELFT>::isPicRel(uint32_t Type) const {
-  return Type != R_X86_64_PC32 && Type != R_X86_64_32;
+  return Type != R_X86_64_PC32 && Type != R_X86_64_32 &&
+         Type != R_X86_64_TPOFF32;
 }
 
 template <class ELFT>
 void X86_64TargetInfo<ELFT>::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type,
                                             uint64_t Val) const {
   // Convert
   //   .byte 0x66
   //   leaq x@tlsgd(%rip), %rdi

lld/trunk/test/ELF/x86-64-reloc-tpoff32-fpic.s

+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: not ld.lld %t.o -shared -o %t.so 2>&1 | FileCheck %s
+
+# CHECK: relocation R_X86_64_TPOFF32 cannot be used against shared object; recompile with -fPIC
+# CHECK: >>> defined in {{.*}}.o
+# CHECK: >>> referenced by {{.*}}.o:(.tdata+0xC)
+
+.section ".tdata", "awT", @progbits
+.globl var
+var:
+
+movq %fs:0, %rax
+leaq var@TPOFF(%rax),%rax