[RelocationResolver] Support R_AARCH64_PREL32

Code from D83800 by Yichao Yu

Author: MaskRay

llvm/lib/Object/RelocationResolver.cpp

@@ -62,6 +62,8 @@ static bool supportsAArch64(uint64_t Type) {
   switch (Type) {
   case ELF::R_AARCH64_ABS32:
   case ELF::R_AARCH64_ABS64:
+  case ELF::R_AARCH64_PREL32:
+  case ELF::R_AARCH64_PREL64:
     return true;
   default:
     return false;
@@ -74,6 +76,10 @@ static uint64_t resolveAArch64(RelocationRef R, uint64_t S, uint64_t A) {
     return (S + getELFAddend(R)) & 0xFFFFFFFF;
   case ELF::R_AARCH64_ABS64:
     return S + getELFAddend(R);
+  case ELF::R_AARCH64_PREL32:
+    return (S + getELFAddend(R) - R.getOffset()) & 0xFFFFFFFF;
+  case ELF::R_AARCH64_PREL64:
+    return S + getELFAddend(R) - R.getOffset();
   default:
     llvm_unreachable("Invalid relocation type");
   }

llvm/test/DebugInfo/AArch64/eh-frame.ll

@@ -0,0 +1,21 @@
+; RUN: llc -filetype=obj -mtriple=aarch64 %s -o %t.o
+; RUN: llvm-readobj -r %t.o | FileCheck %s --check-prefix=REL32
+; RUN: llvm-dwarfdump --eh-frame %t.o 2>&1 | FileCheck %s
+
+; REL32:      R_AARCH64_PREL32 .text 0x0
+; REL32-NEXT: R_AARCH64_PREL32 .text 0x4
+
+; CHECK-NOT:  warning:
+; CHECK: FDE cie=00000000 pc=00000000...00000004
+;; TODO Take relocation into consideration
+; CHECK: FDE cie=00000000 pc=00000000...00000004
+
+define void @foo() {
+entry:
+  ret void
+}
+
+define void @bar() {
+entry:
+  ret void
+}