Revert "Revert "ExecutionEngine: add R_AARCH64_ABS{16,32}""

This reverts commit SVN r313668.  The original test case attempted to
write a pointer value into 16-bits, although the value may exceed the
range representable in 16-bits.  Ensure that the symbol is located in
the address space such that its absolute address is representable in
16-bits.  This should fix the assertion failure that was seen on the
Windows hosts.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313822 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

@@ -354,6 +354,18 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
   default:
     llvm_unreachable("Relocation type not implemented yet!");
     break;
+  case ELF::R_AARCH64_ABS16: {
+    uint64_t Result = Value + Addend;
+    assert(static_cast<int64_t>(Result) >= INT16_MIN && Result < UINT16_MAX);
+    write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU));
+    break;
+  }
+  case ELF::R_AARCH64_ABS32: {
+    uint64_t Result = Value + Addend;
+    assert(static_cast<int64_t>(Result) >= INT32_MIN && Result < UINT32_MAX);
+    write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU));
+    break;
+  }
   case ELF::R_AARCH64_ABS64:
     write(isBE, TargetPtr, Value + Addend);
     break;

test/ExecutionEngine/RuntimeDyld/AArch64/ELF_ARM64_relocations.s

@@ -1,6 +1,6 @@
 # RUN: llvm-mc -triple=arm64-none-linux-gnu -filetype=obj -o %t %s
-# RUN: llvm-rtdyld -triple=arm64-none-linux-gnu -verify -dummy-extern f=0x0123456789abcdef -check=%s %t
-        
+# RUN: llvm-rtdyld -triple=arm64-none-linux-gnu -verify -dummy-extern f=0x0123456789abcdef -dummy-extern symbol=0xf00f -check=%s %t
+
         .globl Q
         .section .dummy, "ax"
 Q:
@@ -82,3 +82,14 @@ r:
 ## f & 0xFFF = 0xdef (bits 11:0 of f)
 ## 0xdef << 10 = 0x37bc00
 # rtdyld-check: *{4}(a) = 0x9137bc00
+
+	.data
+ABS16:
+	.short symbol
+# rtdyld-check: (*{2}ABS16) = symbol[15:0]
+ABS32:
+	.long symbol
+# rtdyld-check: (*{4}ABS32) = symbol[31:0]
+ABS64:
+	.xword symbol
+# rtdyld-check: (*{8}ABS64) = symbol