From 7a86ffb19fd9e74960690cb41caae390832d3b5a Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Fri, 15 Mar 2013 05:51:57 +0000
Subject: [PATCH] Fix the FDE encoding to be relative on ELF.

This is a very late complement to r130637 which fixed this on x86_64. Fixes
pr15448.

Since it looks like that every elf architecture uses this encoding when using
cfi, make it the default for elf. Just exclude mips64el. It has a lovely
.ll -> .o test (ef_frame.ll) that tests that nothing changes in the binary
content of the .eh_frame produced by llc. Oblige it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177141 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/MC/MCObjectFileInfo.cpp | 12 ++++++------
 test/MC/ELF/fde-reloc.s     | 11 +++++++++++
 2 files changed, 17 insertions(+), 6 deletions(-)
 create mode 100644 test/MC/ELF/fde-reloc.s

diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index 2e1a0455696..bafa002e3d4 100644
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -223,6 +223,11 @@ void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
 }
 
 void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
+  // FIXME: Check this. Mips64el is using the base values, which is most likely
+  // incorrect.
+  if (T.getArch() != Triple::mips64el)
+    FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+
   if (T.getArch() == Triple::x86) {
     PersonalityEncoding = (RelocM == Reloc::PIC_)
      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
@@ -230,15 +235,13 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
     LSDAEncoding = (RelocM == Reloc::PIC_)
       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
       : dwarf::DW_EH_PE_absptr;
-    FDEEncoding = FDECFIEncoding = (RelocM == Reloc::PIC_)
+    FDEEncoding = (RelocM == Reloc::PIC_)
       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
       : dwarf::DW_EH_PE_absptr;
     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) {
-    FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
-
     if (RelocM == Reloc::PIC_) {
       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
@@ -261,8 +264,6 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
     }
   }  else if (T.getArch() ==  Triple::aarch64) {
-    FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
-
     // The small model guarantees static code/data size < 4GB, but not where it
     // will be in memory. Most of these could end up >2GB away so even a signed
     // pc-relative 32-bit address is insufficient, theoretically.
@@ -282,7 +283,6 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
   } else if (T.getArch() == Triple::ppc64) {
     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
       dwarf::DW_EH_PE_udata8;
-    FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
     FDEEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
diff --git a/test/MC/ELF/fde-reloc.s b/test/MC/ELF/fde-reloc.s
new file mode 100644
index 00000000000..63ac9766218
--- /dev/null
+++ b/test/MC/ELF/fde-reloc.s
@@ -0,0 +1,11 @@
+// RUN: llvm-mc -filetype=obj %s -o - -triple x86_64-pc-linux | llvm-objdump -r - | FileCheck --check-prefix=X86-64 %s
+// RUN: llvm-mc -filetype=obj %s -o - -triple i686-pc-linux | llvm-objdump -r - | FileCheck --check-prefix=I686 %s
+
+// PR15448
+
+func:
+	.cfi_startproc
+	.cfi_endproc
+
+// X86-64: R_X86_64_PC32
+// I686: R_386_PC32