From c530dd687328d4208f91e62b600d25ec6e7f0f39 Mon Sep 17 00:00:00 2001
From: Fangrui Song <i@maskray.me>
Date: Fri, 17 Jul 2020 23:49:15 -0700
Subject: [PATCH 2/2] [RelocationResolver] Support R_AARCH64_PREL32

Code from D83800 by Yichao Yu
---
 llvm/lib/Object/RelocationResolver.cpp  |  6 ++++++
 llvm/test/DebugInfo/AArch64/eh-frame.ll | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 llvm/test/DebugInfo/AArch64/eh-frame.ll

diff --git llvm/lib/Object/RelocationResolver.cpp llvm/lib/Object/RelocationResolver.cpp
index eedb236f83d..80339ebf7b9 100644
--- llvm/lib/Object/RelocationResolver.cpp
+++ 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");
   }
diff --git llvm/test/DebugInfo/AArch64/eh-frame.ll llvm/test/DebugInfo/AArch64/eh-frame.ll
new file mode 100644
index 00000000000..9651159271e
--- /dev/null
+++ 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
+}
-- 
2.28.0