[PPC] Add a test for toc-relative access on ppc64le.

Adds a simple test for accessing a local global variable in the ElfV2 abi.
Checks that the toc base used is the expected offset from the .TOC. symbol,
and that the offsets for the global are calculated relative to the toc base.

llvm-svn: 328982

lld/test/ELF/ppc64le-toc-rel.s

@@ -0,0 +1,64 @@
+# REQUIRES: ppc
+# RUN: llvm-mc -filetype=obj -triple=powerpc64le-unknown-linux %s -o %t.o
+# RUN: llvm-readobj -relocations %t.o | FileCheck -check-prefix=RELOCS %s
+# RUN: ld.lld %t.o -o %t2
+# RUN: llvm-objdump -D %t2 | FileCheck %s
+
+# Make sure we calculate the offset correctly for a toc-relative access to a
+# global variable as described by the PPC64 Elf V2 abi.
+.abiversion 2
+
+#  int global_a = 55
+   .globl      global_a
+   .section    ".data"
+   .align      2
+   .type       global_a, @object
+   .size       global_a, 4
+   .p2align    2
+global_a:
+   .long   41
+
+
+   .section        ".text"
+   .align 2
+   .global _start
+   .type   _start, @function
+_start:
+.Lfunc_gep0:
+    addis 2, 12, .TOC.-.Lfunc_gep0@ha
+    addi 2, 2, .TOC.-.Lfunc_gep0@l
+.Lfunc_lep0:
+    .localentry _start, .Lfunc_lep0-.Lfunc_gep0
+
+    addis 3, 2, global_a@toc@ha
+    addi 3, 3, global_a@toc@l
+    li 0,1
+    lwa 3, 0(3)
+    sc
+.size   _start,.-_start
+
+# Verify the relocations that get emitted for the global variable are the
+# expected ones.
+# RELOCS:      Relocations [
+# RELOCS-NEXT:   .rela.text {
+# RELOCS:          0x8 R_PPC64_TOC16_HA global_a 0x0
+# RELOCS:          0xC R_PPC64_TOC16_LO global_a 0x0
+
+# Want to check _start for the values used to build the offset from the TOC base
+# to global_a. The .TOC. symbol is expected at address 0x10030000, and the
+# TOC base is address-of(.TOC.) + 0x8000.  The expected offset is:
+# 0x10020000(global_a) - 0x10038000(Toc base) = -0x18000(Offset)
+# which gets materialized into r3 as ((-1 << 16) - 32768).
+
+# CHECK:      Disassembly of section .text:
+# CHECK-NEXT: _start:
+# CHECK:      10010008:       ff ff 62 3c     addis 3, 2, -1
+# CHECK-NEXT: 1001000c:       00 80 63 38     addi 3, 3, -32768
+
+# CHECK:      Disassembly of section .data:
+# CHECK-NEXT: global_a:
+# CHECK-NEXT: 10020000:       29 00 00 00
+
+# CHECK:      Disassembly of section .got:
+# CHECK-NEXT: .got:
+# CHECK-NEXT: 10030000:       00 80 03 10