From c6fa1e95a2784cfba3d5b89e455e4ccfef18794e Mon Sep 17 00:00:00 2001
From: Eric Christopher <echristo@gmail.com>
Date: Thu, 27 Dec 2012 01:07:07 +0000
Subject: [PATCH] Right now all of the relocations are 32-bit dwarf, and the
 relocation information doesn't return an addend for Rel relocations. Go ahead
 and use this information to fix relocation handling inside dwarfdump for
 32-bit ELF REL.

llvm-svn: 171126
---
 include/llvm/Object/RelocVisitor.h           | 34 ++++++++++++++++++++
 lib/DebugInfo/DWARFFormValue.cpp             |  7 ++--
 test/DebugInfo/X86/2010-08-10-DbgConstant.ll |  7 ++--
 3 files changed, 41 insertions(+), 7 deletions(-)

diff --git a/include/llvm/Object/RelocVisitor.h b/include/llvm/Object/RelocVisitor.h
index 9b12946c3a4..2c2dd03b0d0 100644
--- a/include/llvm/Object/RelocVisitor.h
+++ b/include/llvm/Object/RelocVisitor.h
@@ -64,6 +64,18 @@ public:
           HasError = true;
           return RelocToApply();
       }
+    } else if (FileFormat == "ELF32-i386") {
+      switch (RelocType) {
+      case llvm::ELF::R_386_NONE:
+        return visitELF_386_NONE(R);
+      case llvm::ELF::R_386_32:
+        return visitELF_386_32(R, Value);
+      case llvm::ELF::R_386_PC32:
+        return visitELF_386_PC32(R, Value, SecAddr);
+      default:
+        HasError = true;
+        return RelocToApply();
+      }
     }
     return RelocToApply();
   }
@@ -76,6 +88,28 @@ private:
 
   /// Operations
 
+  /// 386-ELF
+  RelocToApply visitELF_386_NONE(RelocationRef R) {
+    return RelocToApply(0, 0);
+  }
+
+  // Ideally the Addend here will be the addend in the data for
+  // the relocation. It's not actually the case for Rel relocations.
+  RelocToApply visitELF_386_32(RelocationRef R, uint64_t Value) {
+    int64_t Addend;
+    R.getAdditionalInfo(Addend);
+    return RelocToApply(Value + Addend, 4);
+  }
+
+  RelocToApply visitELF_386_PC32(RelocationRef R, uint64_t Value,
+                                 uint64_t SecAddr) {
+    int64_t Addend;
+    R.getAdditionalInfo(Addend);
+    uint64_t Address;
+    R.getAddress(Address);
+    return RelocToApply(Value + Addend - Address, 4);
+  }
+
   /// X86-64 ELF
   RelocToApply visitELF_X86_64_NONE(RelocationRef R) {
     return RelocToApply(0, 0);
diff --git a/lib/DebugInfo/DWARFFormValue.cpp b/lib/DebugInfo/DWARFFormValue.cpp
index 1d8ea011100..efc2d966130 100644
--- a/lib/DebugInfo/DWARFFormValue.cpp
+++ b/lib/DebugInfo/DWARFFormValue.cpp
@@ -108,8 +108,8 @@ DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
         = cu->getContext().relocMap().find(*offset_ptr);
       if (AI != cu->getContext().relocMap().end()) {
         const std::pair<uint8_t, int64_t> &R = AI->second;
-        Value.uval = R.second;
-        *offset_ptr += R.first;
+        Value.uval = data.getUnsigned(offset_ptr, cu->getAddressByteSize()) +
+                     R.second;
       } else
         Value.uval = data.getUnsigned(offset_ptr, cu->getAddressByteSize());
       break;
@@ -156,8 +156,7 @@ DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
         = cu->getContext().relocMap().find(*offset_ptr);
       if (AI != cu->getContext().relocMap().end()) {
         const std::pair<uint8_t, int64_t> &R = AI->second;
-        Value.uval = R.second;
-        *offset_ptr += R.first;
+        Value.uval = data.getU32(offset_ptr) + R.second;
       } else
         Value.uval = data.getU32(offset_ptr);
       break;
diff --git a/test/DebugInfo/X86/2010-08-10-DbgConstant.ll b/test/DebugInfo/X86/2010-08-10-DbgConstant.ll
index b3cc35d723f..78f87509953 100644
--- a/test/DebugInfo/X86/2010-08-10-DbgConstant.ll
+++ b/test/DebugInfo/X86/2010-08-10-DbgConstant.ll
@@ -1,6 +1,7 @@
-; RUN: llc  -mtriple=i686-linux -O0 < %s | FileCheck %s
-; CHECK: DW_TAG_constant
-; CHECK-NEXT: .long .Lstring3 #{{#?}} DW_AT_name
+; RUN: llc  -mtriple=i686-linux -O0 -filetype=obj -o %t %s
+; RUN: llvm-dwarfdump %t | FileCheck %s
+; CHECK: DW_TAG_constant [4]
+; CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x0000002c] = "ro")
 
 define void @foo() nounwind ssp {
 entry: