[ELF][AArch64] Support for movz, movk tprel relocations

This patch Implements the R_AARCH64_TLSLE_MOVW_TPREL_G*[_NC]. These are
logically the same calculation as the existing TLSLE relocations with
the result written back to mov[nz] and movk instructions. A typical code
sequence is:
movz x0, #:tprel_g2:foo    // bits [47:32] of R_TLS with overflow check
movk x0, #:tprel_g1_nc:foo // bits [31:16] of R_TLS with no overflow check
movk x0, #:tprel_g0_nc:foo // bits [15:0] of R_TLS with no overflow check

This type of code sequence is usually used with a large code model.

Differential Revision: https://reviews.llvm.org/D65882

Fixes: PR42853
llvm-svn: 368293

Author: smithp35

lld/ELF/Arch/AArch64.cpp

@@ -90,6 +90,11 @@ RelExpr AArch64::getRelExpr(RelType type, const Symbol &s,
   case R_AARCH64_TLSLE_LDST32_TPREL_LO12_NC:
   case R_AARCH64_TLSLE_LDST64_TPREL_LO12_NC:
   case R_AARCH64_TLSLE_LDST128_TPREL_LO12_NC:
+  case R_AARCH64_TLSLE_MOVW_TPREL_G0:
+  case R_AARCH64_TLSLE_MOVW_TPREL_G0_NC:
+  case R_AARCH64_TLSLE_MOVW_TPREL_G1:
+  case R_AARCH64_TLSLE_MOVW_TPREL_G1_NC:
+  case R_AARCH64_TLSLE_MOVW_TPREL_G2:
     return R_TLS;
   case R_AARCH64_CALL26:
   case R_AARCH64_CONDBR19:
@@ -376,20 +381,25 @@ void AArch64::relocateOne(uint8_t *loc, RelType type, uint64_t val) const {
     break;
   case R_AARCH64_MOVW_PREL_G0:
   case R_AARCH64_MOVW_SABS_G0:
+  case R_AARCH64_TLSLE_MOVW_TPREL_G0:
     checkInt(loc, val, 17, type);
     LLVM_FALLTHROUGH;
   case R_AARCH64_MOVW_PREL_G0_NC:
+  case R_AARCH64_TLSLE_MOVW_TPREL_G0_NC:
     writeSMovWImm(loc, val);
     break;
   case R_AARCH64_MOVW_PREL_G1:
   case R_AARCH64_MOVW_SABS_G1:
+  case R_AARCH64_TLSLE_MOVW_TPREL_G1:
     checkInt(loc, val, 33, type);
     LLVM_FALLTHROUGH;
   case R_AARCH64_MOVW_PREL_G1_NC:
+  case R_AARCH64_TLSLE_MOVW_TPREL_G1_NC:
     writeSMovWImm(loc, val >> 16);
     break;
   case R_AARCH64_MOVW_PREL_G2:
   case R_AARCH64_MOVW_SABS_G2:
+  case R_AARCH64_TLSLE_MOVW_TPREL_G2:
     checkInt(loc, val, 49, type);
     LLVM_FALLTHROUGH;
   case R_AARCH64_MOVW_PREL_G2_NC:

lld/test/ELF/aarch64-movw-error.s

@@ -34,3 +34,22 @@ movn x0, #:prel_g0:.-0x10001
 movn x0, #:prel_g1:.-0x100010000
 # CHECK: relocation R_AARCH64_MOVW_PREL_G2 out of range: -281479271677952 is not in [-281474976710656, 281474976710655]
 movn x0, #:prel_g2:.-0x1000100000000
+
+movz x0, #:tprel_g0: v1
+# CHECK: relocation R_AARCH64_TLSLE_MOVW_TPREL_G0 out of range: 65552 is not in [-65536, 65535]
+movz x0, #:tprel_g1: v2
+# CHECK: relocation R_AARCH64_TLSLE_MOVW_TPREL_G1 out of range: 4295032848 is not in [-4294967296, 4294967295]
+movz x0, #:tprel_g2: v3
+# CHECK: relocation R_AARCH64_TLSLE_MOVW_TPREL_G2 out of range: 281479271743496 is not in [-281474976710656, 281474976710655]
+
+.section .tbss,"awT",@nobits
+.balign 16
+.space 0x10000
+v1:
+.quad 0
+.space 0x100000000 - 8
+v2:
+.quad 0
+.space 0x1000000000000 - 16
+v3:
+.quad 0

lld/test/ELF/aarch64-movw-tprel.s

@@ -0,0 +1,65 @@
+# REQUIRES: aarch64
+# RUN: llvm-mc -filetype=obj -triple=aarch64-linux-gnu %s -o %t.o
+# RUN: ld.lld %t.o -o %t
+# RUN: llvm-objdump -d %t
+# RUN: llvm-readobj --symbols %t
+# RUN: llvm-objdump --no-show-raw-insn -d %t | FileCheck %s
+# RUN: llvm-readobj --symbols %t | FileCheck --check-prefix=CHECK-SYM %s
+
+## Test the the local exec relocations that map to:
+## R_AARCH64_TLSLE_MOVW_TPREL_G2
+## R_AARCH64_TLSLE_MOVW_TPREL_G1
+## R_AARCH64_TLSLE_MOVW_TPREL_G1_NC
+## R_AARCH64_TLSLE_MOVW_TPREL_G0
+## R_AARCH64_TLSLE_MOVW_TPREL_G0_NC
+## They calculate the same value as the other TPREL relocations, namely the
+## offset from the thread pointer TP. The G0, G1 and G2 refer to partitions
+## of the result with G2 bits [47:32], G1 bits [31:16] and G0 bits [15:0]
+## the NC variant does not check for overflow.
+## In AArch64 the structure of the TLS at runtime is:
+## | TCB | Alignment Padding | TLS Block |
+## With TP pointing to the start of the TCB. All offsets will be positive.
+
+.text
+## Access variable in first partition
+movz x0, #:tprel_g0:v0
+## TCB + 0 == 16
+# CHECK: mov     x0, #16
+
+# CHECK-SYM:      Name: v0
+# CHECK-SYM-NEXT: Value: 0x0
+
+## Access variable in second partition
+movz x0, #:tprel_g1:v1
+movk x0, #:tprel_g0_nc:v1
+
+## TCB + 65536 across movz and movk
+# CHECK-NEXT: mov     x0, #65536
+# CHECK-NEXT: movk    x0, #16
+
+# CHECK-SYM:      Name: v1
+# CHECK-SYM-NEXT: Value: 0x10000
+
+## Access variable in third partition
+movz x0, #:tprel_g2:v2
+movk x0, #:tprel_g1_nc:v2
+movk x0, #:tprel_g0_nc:v2
+
+## TCB + 65536 + 4294967296 across movz and 2 movk instructions
+# CHECK-NEXT: mov     x0, #4294967296
+# CHECK-NEXT: movk    x0, #1, lsl #16
+# CHECK-NEXT: movk    x0, #16
+
+# CHECK-SYM:     Name: v2
+# CHECK-SYM-NEXT:     Value: 0x100010000
+
+.section .tbss,"awT",@nobits
+.balign 16
+v0:
+.quad 0
+.space 0x10000 - 8
+v1:
+.quad 0
+.space 0x100000000 - 8
+v2:
+.quad 0