[MIPS] Update sandboxing changes for LLVM on MIPS.

This change

- resolves conflicts from previous merges;
- prevents delay slot filler to use instructions that could be masked;
- generates calls to __nacl_read_tp to access thread pointer;
- removes previous (now obsolete) sandboxing code of unaligned loads and stores;
- propagates relocation model to MipsELFObjectWriter, so that it can set
  flag ELF::EF_MIPS_PIC (small hack).

BUG= http://code.google.com/p/nativeclient/issues/detail?id=2275
TEST= pnacl/build.sh all

Review URL: https://codereview.chromium.org/11115013
Patch from Petar Jovanovic <petarj@mips.com>.

1 files changed, 7 insertions, 0 deletions

diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index 2e1604d6b5..3338a17e5c 100644
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -543,9 +543,16 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
                         SectionKind::getDataRel());
 }
 
+// @LOCALMOD-START
+// TODO(petarj): HACK! Find a better way to set ELF::EF_MIPS_PIC flag.
+// See also file lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp.
+Reloc::Model RelocModelOption = Reloc::Default;
+// @LOCALMOD-END
+
 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model relocm,
                                             CodeModel::Model cm,
                                             MCContext &ctx) {
+  RelocModelOption = relocm;  // @LOCALMOD
   RelocM = relocm;
   CMModel = cm;
   Ctx = &ctx;