[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

5 files changed, 82 insertions, 13 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
diff --git a/test/MC/Mips/llvm-mc-fixup-endianness.s b/test/MC/Mips/llvm-mc-fixup-endianness.s
new file mode 100644
index 0000000000..bc6a5d9663
--- /dev/null
+++ b/test/MC/Mips/llvm-mc-fixup-endianness.s
@@ -0,0 +1,6 @@
+# RUN: llvm-mc -show-encoding -mcpu=mips32 -triple mips-unknown-unknown %s | FileCheck -check-prefix=BE %s
+# RUN: llvm-mc -show-encoding -mcpu=mips32 -triple mipsel-unknown-unknown %s | FileCheck -check-prefix=LE %s
+#
+        .text
+        b foo # BE: b foo # encoding: [0x10,0x00,A,A]
+              # LE: b foo # encoding: [A,A,0x00,0x10]
diff --git a/test/MC/Mips/mips_directives.s b/test/MC/Mips/mips_directives.s
index 6780dd0b3c..1a7d61f3ad 100644
--- a/test/MC/Mips/mips_directives.s
+++ b/test/MC/Mips/mips_directives.s
@@ -51,7 +51,7 @@ $BB0_4:
     .set  $tmp7, $BB0_4-$BB0_2
     .set f6,$f6
 # CHECK:    abs.s   $f6, $f7           # encoding: [0x46,0x00,0x39,0x85]
-# CHECK:    lui     $1, %hi($tmp7)     # encoding: [0x3c'A',0x01'A',0x00,0x00]
+# CHECK:    lui     $1, %hi($tmp7)     # encoding: [0x3c,0x01,A,A]
 # CHECK:                               #   fixup A - offset: 0, value: ($tmp7)@ABS_HI, kind: fixup_Mips_HI16
     abs.s  f6,FPU_MASK
     lui $1, %hi($tmp7)
diff --git a/test/MC/Mips/mips_gprel16.s b/test/MC/Mips/mips_gprel16.s
index 716c75ec88..9dd3fa3281 100644
--- a/test/MC/Mips/mips_gprel16.s
+++ b/test/MC/Mips/mips_gprel16.s
@@ -6,6 +6,9 @@
 // RUN: llvm-mc -mcpu=mips32r2 -triple=mipsel-pc-linux -filetype=obj -relocation-model=static %s -o - \
 // RUN: | llvm-objdump -disassemble -mattr +mips32r2 - \
 // RUN: | FileCheck %s
+// RUN: llvm-mc -mcpu=mips32r2 -triple=mips-pc-linux -filetype=obj -relocation-model=static %s -o - \
+// RUN: | llvm-objdump -disassemble -mattr +mips32r2 - \
+// RUN: | FileCheck %s
 
 	.text
 	.abicalls
diff --git a/test/MC/Mips/msa/test_cbranch.s b/test/MC/Mips/msa/test_cbranch.s
index 37b8872560..aa6779b1b4 100644
--- a/test/MC/Mips/msa/test_cbranch.s
+++ b/test/MC/Mips/msa/test_cbranch.s
@@ -7,22 +7,22 @@
 #CHECK:      bnz.w        $w2, 128      # encoding: [0x47,0xc2,0x00,0x20]
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
 #CHECK:      bnz.d        $w3, -128     # encoding: [0x47,0xe3,0xff,0xe0]
-#CHECK:      bnz.b        $w0, SYMBOL0  # encoding: [0x47'A',0x80'A',0x00,0x00]
+#CHECK:      bnz.b        $w0, SYMBOL0  # encoding: [0x47,0x80,A,A]
                                         #   fixup A - offset: 0, value: SYMBOL0, kind: fixup_Mips_PC16
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
-#CHECK:      bnz.h        $w1, SYMBOL1  # encoding: [0x47'A',0xa1'A',0x00,0x00]
+#CHECK:      bnz.h        $w1, SYMBOL1  # encoding: [0x47,0xa1,A,A]
                                         #   fixup A - offset: 0, value: SYMBOL1, kind: fixup_Mips_PC16
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
-#CHECK:      bnz.w        $w2, SYMBOL2  # encoding: [0x47'A',0xc2'A',0x00,0x00]
+#CHECK:      bnz.w        $w2, SYMBOL2  # encoding: [0x47,0xc2,A,A]
                                         #   fixup A - offset: 0, value: SYMBOL2, kind: fixup_Mips_PC16
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
-#CHECK:      bnz.d        $w3, SYMBOL3  # encoding: [0x47'A',0xe3'A',0x00,0x00]
+#CHECK:      bnz.d        $w3, SYMBOL3  # encoding: [0x47,0xe3,A,A]
                                         #   fixup A - offset: 0, value: SYMBOL3, kind: fixup_Mips_PC16
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
 
 #CHECK:      bnz.v        $w0, 4        # encoding: [0x45,0xe0,0x00,0x01]
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
-#CHECK:      bnz.v        $w0, SYMBOL0  # encoding: [0x45'A',0xe0'A',0x00,0x00]
+#CHECK:      bnz.v        $w0, SYMBOL0  # encoding: [0x45,0xe0,A,A]
                                         #   fixup A - offset: 0, value: SYMBOL0, kind: fixup_Mips_PC16
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
 
@@ -34,22 +34,22 @@
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
 #CHECK:      bz.d         $w3, -1024    # encoding: [0x47,0x63,0xff,0x00]
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
-#CHECK:      bz.b         $w0, SYMBOL0  # encoding: [0x47'A',A,0x00,0x00]
+#CHECK:      bz.b         $w0, SYMBOL0  # encoding: [0x47,0x00,A,A]
                                         #   fixup A - offset: 0, value: SYMBOL0, kind: fixup_Mips_PC16
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
-#CHECK:      bz.h         $w1, SYMBOL1  # encoding: [0x47'A',0x21'A',0x00,0x00]
+#CHECK:      bz.h         $w1, SYMBOL1  # encoding: [0x47,0x21,A,A]
                                         #   fixup A - offset: 0, value: SYMBOL1, kind: fixup_Mips_PC16
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
-#CHECK:      bz.w         $w2, SYMBOL2  # encoding: [0x47'A',0x42'A',0x00,0x00]
+#CHECK:      bz.w         $w2, SYMBOL2  # encoding: [0x47,0x42,A,A]
                                         #   fixup A - offset: 0, value: SYMBOL2, kind: fixup_Mips_PC16
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
-#CHECK:      bz.d         $w3, SYMBOL3  # encoding: [0x47'A',0x63'A',0x00,0x00]
+#CHECK:      bz.d         $w3, SYMBOL3  # encoding: [0x47,0x63,A,A]
                                         #   fixup A - offset: 0, value: SYMBOL3, kind: fixup_Mips_PC16
 #CHECK:      nop                        # encoding: [0x00,0x00,0x00,0x00]
 
 #CHECK:      bz.v        $w0, 4        # encoding: [0x45,0x60,0x00,0x01]
 #CHECK:      nop                       # encoding: [0x00,0x00,0x00,0x00]
-#CHECK:      bz.v        $w0, SYMBOL0  # encoding: [0x45'A',0x60'A',0x00,0x00]
+#CHECK:      bz.v        $w0, SYMBOL0  # encoding: [0x45,0x60,A,A]
                                        #   fixup A - offset: 0, value: SYMBOL0, kind: fixup_Mips_PC16
 #CHECK:      nop                       # encoding: [0x00,0x00,0x00,0x00]