[ELF] Account for R_386_TLS_LDO_32 addend

[smeenai]

Summary

This relocation type has an implicit addend. Account for it when
processing the relocation. Add an offset to an existing test to ensure
it gets processed correctly.

Fixes PR32634.

[grimar]

This looks good to me. Please wait for approve from Rui and/or Rafael.

[smeenai]

Thanks for the review and for adjusting the reviewers. I'm requesting a review again so that it shows up in the right queue for @rafael and @ruiu.

[ruiu]

LGTM

If you have a bandwidth, can you check if there's no other missing relocations in the function?

[smeenai]

Thanks for the review!

If you have a bandwidth, can you check if there's no other missing relocations in the function?

I'm testing LLD on x86 against a pretty large codebase (which is how I came across this issue), so I suspect I'll come across any other missing cases in the process. I'll try to spot check this though.

lld/trunk/ELF/Target.cpp

case R_386_PC16:
     return SignExtend64<16>(read16le(Buf));
   case R_386_32:
   case R_386_GOT32:
   case R_386_GOT32X:
   case R_386_GOTOFF:
   case R_386_GOTPC:
   case R_386_PC32:
   case R_386_PLT32:
+  case R_386_TLS_LDO_32:
   case R_386_TLS_LE:
     return SignExtend64<32>(read32le(Buf));
   }
 }
 
 void X86TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type,
                                 uint64_t Val) const {
   // R_386_{PC,}{8,16} are not part of the i386 psABI, but they are

lld/trunk/test/ELF/tls-dynamic-i686.s

  .size tls1, 4
 
 .type  tls2,@object
 .globl tls2
 .hidden tls2
 .align 4
 tls2:
  .long 0
- .size tls2, 4
+ .size tls2, 8
 
 .section .text
 .globl _start
 _start:
 leal tls0@tlsgd(,%ebx,1),%eax
 call __tls_get_addr@plt
 
 leal tls1@tlsgd(,%ebx,1),%eax
 call __tls_get_addr@plt
 
 leal tls2@tlsldm(%ebx),%eax
 call __tls_get_addr@plt
 leal tls2@dtpoff(%eax),%edx
 
 leal tls2@tlsldm(%ebx),%eax
 call __tls_get_addr@plt
-leal tls2@dtpoff(%eax),%edx
+leal tls2@dtpoff+4(%eax),%edx
 
 movl %gs:0,%eax
 addl tls0@gotntpoff(%ebx),%eax
 
 movl %gs:0,%eax
 addl tls1@gotntpoff(%ebx),%eax
 
 // CHECK:      Name: .got (

 // DIS-NEXT: 1013: e8 58 00 00 00        calll 88
 // Local dynamic model:
 // -16 is a local module tls index offset.
 // DIS-NEXT: 1018: 8d 83 f0 ff ff ff leal -16(%ebx), %eax
 // DIS-NEXT: 101e: e8 4d 00 00 00    calll 77
 // DIS-NEXT: 1023: 8d 90 08 00 00 00 leal 8(%eax), %edx
 // DIS-NEXT: 1029: 8d 83 f0 ff ff ff leal -16(%ebx), %eax
 // DIS-NEXT: 102f: e8 3c 00 00 00    calll 60
-// DIS-NEXT: 1034: 8d 90 08 00 00 00 leal 8(%eax), %edx
+// DIS-NEXT: 1034: 8d 90 0c 00 00 00 leal 12(%eax), %edx
 // Initial exec model:
 // DIS-NEXT: 103a: 65 a1 00 00 00 00 movl %gs:0, %eax
 // DIS-NEXT: 1040: 03 83 f8 ff ff ff addl -8(%ebx), %eax
 // DIS-NEXT: 1046: 65 a1 00 00 00 00 movl %gs:0, %eax
 // DIS-NEXT: 104c: 03 83 fc ff ff ff addl -4(%ebx), %eax