[lld] [ELF/AArch64] Fix TLS IE to LE relax for local symbols

[zatrazz]

Summary

This patch fix the TLS relax optimization when transforming Initial-Exec
to Local-Exec for local symbols (which can not be preempted).

[ruiu]

ELF/Target.cpp

1474

What is this change for?

[grimar]

test/ELF/aarch64-tls-iele.s

14

Please align accordinly, remove space after ':'

11000: 00 00 a0 d2     movz    x0, #0, lsl #16
11004: 80 02 80 f2     movk    x0, #0x14
11008: 00 00 a0 d2     movz    x0, #0, lsl #16

Second is that you probably want to use "CHECK-NEXT":

# CHECK:            11000:  00 00 a0 d2     movz    x0, #0, lsl #16
# CHECK-NEXT:  11004:  80 02 80 f2      movk    x0, #0x14
# CHECK-NEXT:  11008:  00 00 a0 d2     movz    x0, #0, lsl #16

And the last is that this testcase contains different spacing style:
"# RUN" vs "#CHECK" for example. Please choose one style to follow in a single test. That probably should be fixed separatelly.

[zatrazz]

ELF/Target.cpp

1474

The logic is wrong for local symbols, where S is nullptr. At ELF/InputSection.cpp:219, if the Body is nullptr then it uses getLocalRelTarget. Also the change on 'AArch64TargetInfo::needsGot' is to make the same code uses getVA instead of getGotVA.

test/ELF/aarch64-tls-iele.s

14

Yes, the spacing is weird, I will fix it.

[zatrazz]

Fix format issues.

[zatrazz]

Rebase against trunk and ping.

[zatrazz]

Ping.

[grimar]

You abandoned this. I guess that was mistake ?

ELF/Target.cpp

case R_AARCH64_TLSDESC_CALL: {
     if (S.isPreemptible())
       fatal("unsupported TLS optimization");
     uint64_t X = S.getVA<ELF64LE>();
     relocateTlsGdToLe(Type, Loc, BufEnd, P, X);
     return 0;
   }
   case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21:
   case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC:
-    relocateTlsIeToLe(Type, Loc, BufEnd, P, S.getVA<ELF64LE>());
+    relocateTlsIeToLe(Type, Loc, BufEnd, P, SA);
     return 0;
   }
   llvm_unreachable("unknown TLS optimization");
 }
 
 // Global-Dynamic relocations can be relaxed to Local-Exec if both binary is
 // an executable and target is final (can notbe preempted).
 void AArch64TargetInfo::relocateTlsGdToLe(uint32_t Type, uint8_t *Loc,

test/ELF/aarch64-tls-iele.s

 # RUN: llvm-mc -filetype=obj -triple=aarch64-unknown-linux %p/Inputs/aarch64-tls-ie.s -o %ttlsie.o
 # RUN: llvm-mc -filetype=obj -triple=aarch64-unknown-linux %s -o %tmain.o
 # RUN: ld.lld %tmain.o %ttlsie.o -o %tout
 # RUN: llvm-objdump -d %tout | FileCheck %s
 # RUN: llvm-readobj -s -r %tout | FileCheck -check-prefix=RELOC %s
 # REQUIRES: aarch64
 
-#Local-Dynamic to Initial-Exec relax creates no
-#RELOC:      Relocations [
-#RELOC-NEXT: ]
+# Initial-Exec to Local-Exec relax creates no dynamic relocations.
+# RELOC:      Relocations [
+# RELOC-NEXT: ]
 
 # TCB size = 0x16 and foo is first element from TLS register.
-#CHECK: Disassembly of section .text:
-#CHECK: _start:
-#CHECK:  11000: 00 00 a0 d2 movz  x0, #0, lsl #16
-#CHECK:  11004: 00 02 80 f2   movk  x0, #0x10
+# CHECK: Disassembly of section .text:
+# CHECK: _start:
+# CHECK-NEXT: 11000:  00 00 a0 d2   movz   x0, #0, lsl #16
+# CHECK-NEXT: 11004:  80 02 80 f2   movk   x0, #0x14
+# CHECK-NEXT: 11008:  00 00 a0 d2   movz   x0, #0, lsl #16
+# CHECK-NEXT: 1100c:  00 02 80 f2   movk   x0, #0x10
+
+.section .tdata
+.align 2
+.type foo_local, %object
+.size foo_local, 4
+foo_local:
+.word 5
+.text
 
 .globl _start
 _start:
  adrp    x0, :gottprel:foo
  ldr     x0, [x0, :gottprel_lo12:foo]
+ adrp    x0, :gottprel:foo_local
+ ldr     x0, [x0, :gottprel_lo12:foo_local]