From 678c35c3861df3d5882553da45e79a89dae20294 Mon Sep 17 00:00:00 2001
From: Michael Liao <michael.liao@intel.com>
Date: Tue, 30 Oct 2012 17:33:39 +0000
Subject: [PATCH] Enable ELF machine type to be specified explicitly in X86
 backend

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167027 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp |  4 +--
 .../X86/MCTargetDesc/X86ELFObjectWriter.cpp   | 25 +++++++++++--------
 lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h |  5 ++--
 3 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp b/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
index 0ca1209449f..467edadc7e0 100644
--- a/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
+++ b/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
@@ -354,7 +354,7 @@ public:
     : ELFX86AsmBackend(T, OSABI, CPU) {}
 
   MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
-    return createX86ELFObjectWriter(OS, /*Is64Bit*/ false, OSABI);
+    return createX86ELFObjectWriter(OS, /*IsELF64*/ false, OSABI, ELF::EM_386);
   }
 };
 
@@ -364,7 +364,7 @@ public:
     : ELFX86AsmBackend(T, OSABI, CPU) {}
 
   MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
-    return createX86ELFObjectWriter(OS, /*Is64Bit*/ true, OSABI);
+    return createX86ELFObjectWriter(OS, /*IsELF64*/ true, OSABI, ELF::EM_X86_64);
   }
 };
 
diff --git a/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp b/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
index 5a42a801825..de80dd835e9 100644
--- a/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
+++ b/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
@@ -20,7 +20,7 @@ using namespace llvm;
 namespace {
   class X86ELFObjectWriter : public MCELFObjectTargetWriter {
   public:
-    X86ELFObjectWriter(bool is64Bit, uint8_t OSABI);
+    X86ELFObjectWriter(bool IsELF64, uint8_t OSABI, uint16_t EMachine);
 
     virtual ~X86ELFObjectWriter();
   protected:
@@ -30,10 +30,11 @@ namespace {
   };
 }
 
-X86ELFObjectWriter::X86ELFObjectWriter(bool Is64Bit, uint8_t OSABI)
-  : MCELFObjectTargetWriter(Is64Bit, OSABI,
-                            Is64Bit ?  ELF::EM_X86_64 : ELF::EM_386,
-                            /*HasRelocationAddend*/ Is64Bit) {}
+X86ELFObjectWriter::X86ELFObjectWriter(bool IsELF64, uint8_t OSABI,
+                                       uint16_t EMachine)
+  : MCELFObjectTargetWriter(IsELF64, OSABI, EMachine,
+                            // Only i386 uses Rel instead of RelA.
+                            /*HasRelocationAddend*/ EMachine != ELF::EM_386) {}
 
 X86ELFObjectWriter::~X86ELFObjectWriter()
 {}
@@ -48,7 +49,7 @@ unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
   MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
     MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
   unsigned Type;
-  if (is64Bit()) {
+  if (getEMachine() == ELF::EM_X86_64) {
     if (IsPCRel) {
       switch ((unsigned)Fixup.getKind()) {
       default: llvm_unreachable("invalid fixup kind!");
@@ -130,7 +131,7 @@ unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
       case FK_Data_1: Type = ELF::R_X86_64_8; break;
       }
     }
-  } else {
+  } else if (getEMachine() == ELF::EM_386) {
     if (IsPCRel) {
       switch ((unsigned)Fixup.getKind()) {
       default: llvm_unreachable("invalid fixup kind!");
@@ -210,15 +211,17 @@ unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
       case FK_Data_1: Type = ELF::R_386_8; break;
       }
     }
-  }
+  } else
+    llvm_unreachable("Unsupported ELF machine type.");
 
   return Type;
 }
 
 MCObjectWriter *llvm::createX86ELFObjectWriter(raw_ostream &OS,
-                                               bool Is64Bit,
-                                               uint8_t OSABI) {
+                                               bool IsELF64,
+                                               uint8_t OSABI,
+                                               uint16_t EMachine) {
   MCELFObjectTargetWriter *MOTW =
-    new X86ELFObjectWriter(Is64Bit, OSABI);
+    new X86ELFObjectWriter(IsELF64, OSABI, EMachine);
   return createELFObjectWriter(MOTW, OS,  /*IsLittleEndian=*/true);
 }
diff --git a/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h b/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h
index 0b0989bff11..981aa1a2b91 100644
--- a/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h
+++ b/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h
@@ -89,8 +89,9 @@ MCObjectWriter *createX86MachObjectWriter(raw_ostream &OS,
 
 /// createX86ELFObjectWriter - Construct an X86 ELF object writer.
 MCObjectWriter *createX86ELFObjectWriter(raw_ostream &OS,
-                                         bool Is64Bit,
-                                         uint8_t OSABI);
+                                         bool IsELF64,
+                                         uint8_t OSABI,
+                                         uint16_t EMachine);
 /// createX86WinCOFFObjectWriter - Construct an X86 Win COFF object writer.
 MCObjectWriter *createX86WinCOFFObjectWriter(raw_ostream &OS, bool Is64Bit);
 } // End llvm namespace