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

llvm-svn: 209514
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@dsandersllvm
dsandersllvm committed May 23, 2014
1 parent 8966caa commit 683ed96
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Showing 5 changed files with 82 additions and 13 deletions.
64 changes: 62 additions & 2 deletions llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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.
//
Expand Down Expand Up @@ -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
Expand Down
6 changes: 6 additions & 0 deletions llvm/test/MC/Mips/llvm-mc-fixup-endianness.s
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Original file line number Diff line number Diff line change
@@ -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]
2 changes: 1 addition & 1 deletion llvm/test/MC/Mips/mips_directives.s
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Original file line number Diff line number Diff line change
Expand Up @@ -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)
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3 changes: 3 additions & 0 deletions llvm/test/MC/Mips/mips_gprel16.s
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,9 @@

// 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
Expand Down
20 changes: 10 additions & 10 deletions llvm/test/MC/Mips/msa/test_cbranch.s
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Original file line number Diff line number Diff line change
Expand Up @@ -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]

Expand All @@ -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]

Expand Down

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