From eeba593364290ec3ea51e191211e1150ac551b24 Mon Sep 17 00:00:00 2001
From: Logan Chien <loganchien@google.com>
Date: Thu, 20 Sep 2012 10:55:34 +0800
Subject: [PATCH] Fix MIPS exception personality relocation.

Some MIPS executable loaders prohibit the relocation
in the read-only section.  Thus, we have to use
DW_EH_PE_indirect instead.
---
 .../lib/CodeGen/AsmPrinter/DwarfCFIException.cpp   |    3 +-
 .../lib/CodeGen/TargetLoweringObjectFileImpl.cpp   |   13 +++----
 llvm-3.1/lib/MC/MCObjectFileInfo.cpp               |   16 ++++++++-
 llvm-3.1/test/CodeGen/Mips/ehframe-indirect.ll     |   33 ++++++++++++++++++++
 4 files changed, 55 insertions(+), 10 deletions(-)
 create mode 100644 llvm-3.1/test/CodeGen/Mips/ehframe-indirect.ll

diff --git a/llvm-3.1/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/llvm-3.1/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
index d975f1f..a9d4774 100644
--- a/llvm-3.1/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
+++ b/llvm-3.1/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
@@ -59,7 +59,8 @@ void DwarfCFIException::EndModule() {
 
   unsigned PerEncoding = TLOF.getPersonalityEncoding();
 
-  if ((PerEncoding & 0x70) != dwarf::DW_EH_PE_pcrel)
+  if ((PerEncoding & 0x70) != dwarf::DW_EH_PE_pcrel &&
+      (PerEncoding & 0x80) != dwarf::DW_EH_PE_indirect)
     return;
 
   // Emit references to all used personality functions
diff --git a/llvm-3.1/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm-3.1/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 3660cf7..840d233 100644
--- a/llvm-3.1/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm-3.1/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -49,15 +49,14 @@ TargetLoweringObjectFileELF::getCFIPersonalitySymbol(const GlobalValue *GV,
                                                      Mangler *Mang,
                                                 MachineModuleInfo *MMI) const {
   unsigned Encoding = getPersonalityEncoding();
-  switch (Encoding & 0x70) {
-  default:
-    report_fatal_error("We do not support this DWARF encoding yet!");
-  case dwarf::DW_EH_PE_absptr:
-    return  Mang->getSymbol(GV);
-  case dwarf::DW_EH_PE_pcrel: {
+  if ((Encoding & 0x70) == dwarf::DW_EH_PE_pcrel ||
+      (Encoding & 0x80) == dwarf::DW_EH_PE_indirect) {
     return getContext().GetOrCreateSymbol(StringRef("DW.ref.") +
                                           Mang->getSymbol(GV)->getName());
-  }
+  } else if ((Encoding & 0x70) == dwarf::DW_EH_PE_absptr) {
+    return  Mang->getSymbol(GV);
+  } else {
+    report_fatal_error("We do not support this DWARF encoding yet!");
   }
 }
 
diff --git a/llvm-3.1/lib/MC/MCObjectFileInfo.cpp b/llvm-3.1/lib/MC/MCObjectFileInfo.cpp
index b22ae33..8b2ed03 100644
--- a/llvm-3.1/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm-3.1/lib/MC/MCObjectFileInfo.cpp
@@ -219,7 +219,8 @@ void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
 }
 
 void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
-  if (T.getArch() == Triple::x86) {
+  switch (T.getArch()) {
+  case Triple::x86:
     PersonalityEncoding = (RelocM == Reloc::PIC_)
      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
      : dwarf::DW_EH_PE_absptr;
@@ -232,7 +233,9 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
     TTypeEncoding = (RelocM == Reloc::PIC_)
      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
      : dwarf::DW_EH_PE_absptr;
-  } else if (T.getArch() == Triple::x86_64) {
+    break;
+
+  case Triple::x86_64:
     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 
     if (RelocM == Reloc::PIC_) {
@@ -256,6 +259,15 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
       TTypeEncoding = (CMModel == CodeModel::Small)
         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
     }
+    break;
+
+  case Triple::mips:
+  case Triple::mipsel:
+    PersonalityEncoding = dwarf::DW_EH_PE_indirect;
+    break;
+
+  default:
+    break;
   }
 
   // Solaris requires different flags for .eh_frame to seemingly every other
diff --git a/llvm-3.1/test/CodeGen/Mips/ehframe-indirect.ll b/llvm-3.1/test/CodeGen/Mips/ehframe-indirect.ll
new file mode 100644
index 0000000..db422a7
--- /dev/null
+++ b/llvm-3.1/test/CodeGen/Mips/ehframe-indirect.ll
@@ -0,0 +1,33 @@
+; RUN: llc -march=mipsel < %s | FileCheck %s
+
+define i32 @main() {
+; CHECK: .cfi_startproc
+; CHECK: .cfi_personality 128, DW.ref.__gxx_personality_v0
+
+entry:
+  invoke void @foo() to label %cont unwind label %lpad
+; CHECK: foo
+; CHECK: jalr
+
+lpad:
+  %0 = landingpad { i8*, i32 } personality i8*
+    bitcast (i32 (...)* @__gxx_personality_v0 to i8*) catch i8* null
+  ret i32 0
+
+cont:
+  ret i32 0
+}
+; CHECK: .cfi_endproc
+
+declare i32 @__gxx_personality_v0(...)
+
+declare void @foo()
+
+; CHECK: .hidden DW.ref.__gxx_personality_v0
+; CHECK: .weak DW.ref.__gxx_personality_v0
+; CHECK: .section .data.DW.ref.__gxx_personality_v0,"aGw",@progbits,DW.ref.__gxx_personality_v0,comdat
+; CHECK: .align 2
+; CHECK: .type DW.ref.__gxx_personality_v0,@object
+; CHECK: .size DW.ref.__gxx_personality_v0, 4
+; CHECK: DW.ref.__gxx_personality_v0:
+; CHECK: .4byte __gxx_personality_v0
-- 
1.7.7.3