[mips] Work around inconsistency in llvm-mc's placement of fixup markers

Summary:
Add a second fixup table to MipsAsmBackend::getFixupKindInfo() to correctly
position llvm-mc's fixup placeholders for big-endian.

See PR19836 for full details of the issue. To summarize, the fixup placeholders
do not account for endianness properly and the implementations of
getFixupKindInfo() for each target are measuring MCFixupKindInfo.TargetOffset
from different ends of the instruction encoding to compensate.

Reviewers: jkolek, zoran.jovanovic, vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D3889

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209514 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 62 insertions, 2 deletions

diff --git a/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp b/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
index 153974e470..332f7ea7a2 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
@@ -189,7 +189,7 @@ void MipsAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
 
 const MCFixupKindInfo &MipsAsmBackend::
 getFixupKindInfo(MCFixupKind Kind) const {
-  const static MCFixupKindInfo Infos[Mips::NumTargetFixupKinds] = {
+  const static MCFixupKindInfo LittleEndianInfos[Mips::NumTargetFixupKinds] = {
     // This table *must* be in same the order of fixup_* kinds in
     // MipsFixupKinds.h.
     //
@@ -246,12 +246,72 @@ getFixupKindInfo(MCFixupKind Kind) const {
     { "fixup_MICROMIPS_TLS_TPREL_LO16",  0,     16,   0 }
   };
 
+  const static MCFixupKindInfo BigEndianInfos[Mips::NumTargetFixupKinds] = {
+    // This table *must* be in same the order of fixup_* kinds in
+    // MipsFixupKinds.h.
+    //
+    // name                    offset  bits  flags
+    { "fixup_Mips_16",          16,     16,   0 },
+    { "fixup_Mips_32",           0,     32,   0 },
+    { "fixup_Mips_REL32",        0,     32,   0 },
+    { "fixup_Mips_26",           6,     26,   0 },
+    { "fixup_Mips_HI16",        16,     16,   0 },
+    { "fixup_Mips_LO16",        16,     16,   0 },
+    { "fixup_Mips_GPREL16",     16,     16,   0 },
+    { "fixup_Mips_LITERAL",     16,     16,   0 },
+    { "fixup_Mips_GOT_Global",  16,     16,   0 },
+    { "fixup_Mips_GOT_Local",   16,     16,   0 },
+    { "fixup_Mips_PC16",        16,     16,  MCFixupKindInfo::FKF_IsPCRel },
+    { "fixup_Mips_CALL16",      16,     16,   0 },
+    { "fixup_Mips_GPREL32",      0,     32,   0 },
+    { "fixup_Mips_SHIFT5",      21,      5,   0 },
+    { "fixup_Mips_SHIFT6",      21,      5,   0 },
+    { "fixup_Mips_64",           0,     64,   0 },
+    { "fixup_Mips_TLSGD",       16,     16,   0 },
+    { "fixup_Mips_GOTTPREL",    16,     16,   0 },
+    { "fixup_Mips_TPREL_HI",    16,     16,   0 },
+    { "fixup_Mips_TPREL_LO",    16,     16,   0 },
+    { "fixup_Mips_TLSLDM",      16,     16,   0 },
+    { "fixup_Mips_DTPREL_HI",   16,     16,   0 },
+    { "fixup_Mips_DTPREL_LO",   16,     16,   0 },
+    { "fixup_Mips_Branch_PCRel",16,     16,  MCFixupKindInfo::FKF_IsPCRel },
+    { "fixup_Mips_GPOFF_HI",    16,     16,   0 },
+    { "fixup_Mips_GPOFF_LO",    16,     16,   0 },
+    { "fixup_Mips_GOT_PAGE",    16,     16,   0 },
+    { "fixup_Mips_GOT_OFST",    16,     16,   0 },
+    { "fixup_Mips_GOT_DISP",    16,     16,   0 },
+    { "fixup_Mips_HIGHER",      16,     16,   0 },
+    { "fixup_Mips_HIGHEST",     16,     16,   0 },
+    { "fixup_Mips_GOT_HI16",    16,     16,   0 },
+    { "fixup_Mips_GOT_LO16",    16,     16,   0 },
+    { "fixup_Mips_CALL_HI16",   16,     16,   0 },
+    { "fixup_Mips_CALL_LO16",   16,     16,   0 },
+    { "fixup_MICROMIPS_26_S1",   6,     26,   0 },
+    { "fixup_MICROMIPS_HI16",   16,     16,   0 },
+    { "fixup_MICROMIPS_LO16",   16,     16,   0 },
+    { "fixup_MICROMIPS_GOT16",  16,     16,   0 },
+    { "fixup_MICROMIPS_PC16_S1",16,     16,   MCFixupKindInfo::FKF_IsPCRel },
+    { "fixup_MICROMIPS_CALL16", 16,     16,   0 },
+    { "fixup_MICROMIPS_GOT_DISP",        16,     16,   0 },
+    { "fixup_MICROMIPS_GOT_PAGE",        16,     16,   0 },
+    { "fixup_MICROMIPS_GOT_OFST",        16,     16,   0 },
+    { "fixup_MICROMIPS_TLS_GD",          16,     16,   0 },
+    { "fixup_MICROMIPS_TLS_LDM",         16,     16,   0 },
+    { "fixup_MICROMIPS_TLS_DTPREL_HI16", 16,     16,   0 },
+    { "fixup_MICROMIPS_TLS_DTPREL_LO16", 16,     16,   0 },
+    { "fixup_MICROMIPS_TLS_TPREL_HI16",  16,     16,   0 },
+    { "fixup_MICROMIPS_TLS_TPREL_LO16",  16,     16,   0 }
+  };
+
   if (Kind < FirstTargetFixupKind)
     return MCAsmBackend::getFixupKindInfo(Kind);
 
   assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
           "Invalid kind!");
-  return Infos[Kind - FirstTargetFixupKind];
+
+  if (IsLittle)
+    return LittleEndianInfos[Kind - FirstTargetFixupKind];
+  return BigEndianInfos[Kind - FirstTargetFixupKind];
 }
 
 /// WriteNopData - Write an (optimal) nop sequence of Count bytes