[ELF] - Properly check that R_X86_64_PC32 and R_X86_64_32 relocations are disallowed in DSO.

[grimar]

Summary

getDynRel() contains the next code:

uint32_t X86_64TargetInfo::getDynRel(uint32_t Type) const {
  if (Config->Shared && (Type == R_X86_64_PC32 || Type == R_X86_64_32))
    error(getRelName(Type) + " cannot be a dynamic relocation");
  return Type;
}

where error was never thown/catched previously when running testcases because adjustExpr() method
consumed that error check. adjustExpr() errors out if dynamic relocations happens against the readonly segment.

I think initially we wanted to check that these two relocations are not present when linking DSO because of
possible overflow in runtime. Patch moves them to writable segment in testcases to allow
error check above to trigger.

[• rafael]

LGTM.

lld/trunk/test/ELF/x86-64-reloc-32-fpic.s

 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
 # RUN: not ld.lld -shared %t.o -o %t.so 2>&1 | FileCheck %s
-# CHECK: can't create dynamic relocation R_X86_64_32 against readonly segment
+# CHECK: relocation R_X86_64_32 cannot be used when making a shared object; recompile with -fPIC.
 
+.data
 .long _shared

lld/trunk/test/ELF/x86-64-reloc-pc32-fpic.s

 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
 # RUN: not ld.lld -shared %t.o -o %t.so 2>&1 | FileCheck %s
-# CHECK: can't create dynamic relocation R_X86_64_PC32 against readonly segment
+# CHECK: relocation R_X86_64_PC32 cannot be used when making a shared object; recompile with -fPIC.
 
+.data
 call _shared