forked from OSchip/llvm-project
[ELF][MIPS] Calculate combined addend for R_MIPS_GOT16 against local symbol
R_MIPS_GOT16 relocation against local symbol requires index of a local GOT entry which contains page address corresponds to sum of the symbol address and addend. The addend in that case is calculated using addends from the R_MIPS_GOT16 and paired R_MIPS_LO16 relocations. Differential Revision: http://reviews.llvm.org/D17610 llvm-svn: 261930
This commit is contained in:
Simon Atanasyan
parent
ad9f53e959
commit
860fbf094e
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@ -14,9 +14,12 @@
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#include "OutputSections.h"
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#include "Target.h"
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#include "llvm/Support/Endian.h"
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using namespace llvm;
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using namespace llvm::ELF;
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using namespace llvm::object;
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using namespace llvm::support::endian;
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using namespace lld;
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using namespace lld::elf2;
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@ -141,6 +144,21 @@ void InputSection<ELFT>::copyRelocations(uint8_t *Buf,
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}
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}
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static uint32_t getMipsPairedRelocType(uint32_t Type) {
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if (Config->EMachine != EM_MIPS)
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return R_MIPS_NONE;
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switch (Type) {
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case R_MIPS_HI16:
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return R_MIPS_LO16;
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case R_MIPS_PCHI16:
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return R_MIPS_PCLO16;
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case R_MICROMIPS_HI16:
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return R_MICROMIPS_LO16;
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default:
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return R_MIPS_NONE;
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}
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}
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template <class ELFT>
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template <bool isRela>
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uint8_t *
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@ -151,15 +169,7 @@ InputSectionBase<ELFT>::findMipsPairedReloc(uint8_t *Buf, uint32_t SymIndex,
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// itself and addend of paired relocation. ABI requires to compute such
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// combined addend in case of REL relocation record format only.
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// See p. 4-17 at ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
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if (isRela || Config->EMachine != EM_MIPS)
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return nullptr;
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if (Type == R_MIPS_HI16)
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Type = R_MIPS_LO16;
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else if (Type == R_MIPS_PCHI16)
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Type = R_MIPS_PCLO16;
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else if (Type == R_MICROMIPS_HI16)
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Type = R_MICROMIPS_LO16;
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else
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if (isRela || Type == R_MIPS_NONE)
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return nullptr;
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for (const auto &RI : Rels) {
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if (RI.getType(Config->Mips64EL) != Type)
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@ -225,20 +235,31 @@ void InputSectionBase<ELFT>::relocate(uint8_t *Buf, uint8_t *BufEnd,
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uintX_t A = getAddend<ELFT>(RI);
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if (!Body) {
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uintX_t SymVA = getLocalRelTarget(*File, RI, A);
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uint8_t *PairedLoc = nullptr;
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if (Config->EMachine == EM_MIPS) {
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if (Type == R_MIPS_GPREL16 || Type == R_MIPS_GPREL32)
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// We need to adjust SymVA value in case of R_MIPS_GPREL16/32
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// relocations because they use the following expression to calculate
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// the relocation's result for local symbol: S + A + GP0 - G.
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SymVA += File->getMipsGp0();
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else if (Type == R_MIPS_GOT16)
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else if (Type == R_MIPS_GOT16) {
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// R_MIPS_GOT16 relocation against local symbol requires index of
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// a local GOT entry which contains page address corresponds
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// to the symbol address.
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SymVA = Out<ELFT>::Got->getMipsLocalPageAddr(SymVA);
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// to sum of the symbol address and addend. The addend in that case
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// is calculated using addends from R_MIPS_GOT16 and paired
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// R_MIPS_LO16 relocations.
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const endianness E = ELFT::TargetEndianness;
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uint8_t *LowLoc =
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findMipsPairedReloc(Buf, SymIndex, R_MIPS_LO16, NextRelocs);
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uint64_t AHL = read32<E>(BufLoc) << 16;
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if (LowLoc)
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AHL += SignExtend64<16>(read32<E>(LowLoc));
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SymVA = Out<ELFT>::Got->getMipsLocalPageAddr(SymVA + AHL);
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} else
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PairedLoc = findMipsPairedReloc(
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Buf, SymIndex, getMipsPairedRelocType(Type), NextRelocs);
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}
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Target->relocateOne(BufLoc, BufEnd, Type, AddrLoc, SymVA, 0,
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findMipsPairedReloc(Buf, SymIndex, Type, NextRelocs));
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Target->relocateOne(BufLoc, BufEnd, Type, AddrLoc, SymVA, 0, PairedLoc);
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continue;
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}
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@ -284,7 +305,9 @@ void InputSectionBase<ELFT>::relocate(uint8_t *Buf, uint8_t *BufEnd,
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}
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uintX_t Size = Body->getSize<ELFT>();
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Target->relocateOne(BufLoc, BufEnd, Type, AddrLoc, SymVA + A, Size + A,
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findMipsPairedReloc(Buf, SymIndex, Type, NextRelocs));
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findMipsPairedReloc(Buf, SymIndex,
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getMipsPairedRelocType(Type),
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NextRelocs));
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}
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}
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@ -10,17 +10,21 @@
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# CHECK: Disassembly of section .text:
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# CHECK-NEXT: __start:
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# CHECK-NEXT: 10000: 8f 88 80 18 lw $8, -32744($gp)
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# CHECK-NEXT: 10004: 21 08 00 1c addi $8, $8, 28
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# CHECK-NEXT: 10004: 21 08 00 2c addi $8, $8, 44
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# CHECK-NEXT: 10008: 8f 88 80 1c lw $8, -32740($gp)
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# CHECK-NEXT: 1000c: 21 08 00 00 addi $8, $8, 0
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# CHECK-NEXT: 1000c: 21 08 90 00 addi $8, $8, -28672
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# CHECK-NEXT: 10010: 8f 88 80 20 lw $8, -32736($gp)
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# CHECK-NEXT: 10014: 21 08 00 04 addi $8, $8, 4
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# CHECK-NEXT: 10018: 8f 88 80 24 lw $8, -32732($gp)
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# CHECK-NEXT: 10014: 21 08 90 04 addi $8, $8, -28668
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# CHECK-NEXT: 10018: 8f 88 80 20 lw $8, -32736($gp)
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# CHECK-NEXT: 1001c: 21 08 10 04 addi $8, $8, 4100
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# CHECK-NEXT: 10020: 8f 88 80 24 lw $8, -32732($gp)
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# CHECK-NEXT: 10024: 21 08 10 08 addi $8, $8, 4104
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# CHECK-NEXT: 10028: 8f 88 80 2c lw $8, -32724($gp)
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#
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# CHECK: SYMBOL TABLE:
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# CHECK: 0001001c .text 00000000 $LC0
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# CHECK: 00030000 .data 00000000 $LC1
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# CHECK: 00030004 .data 00000000 .hidden bar
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# CHECK: 0001002c .text 00000000 $LC0
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# CHECK: 00039000 .data 00000000 $LC1
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# CHECK: 00051008 .data 00000000 .hidden bar
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# CHECK: 00000000 *UND* 00000000 foo
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# GOT: Relocations [
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@ -47,22 +51,38 @@
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# GOT-NEXT: Address: 0x20008
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# GOT-NEXT: Access: -32744
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# GOT-NEXT: Initial: 0x10000
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# ^-- (0x1002c + 0x8000) & ~0xffff
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# GOT-NEXT: }
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# GOT-NEXT: Entry {
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# GOT-NEXT: Address: 0x2000C
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# GOT-NEXT: Access: -32740
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# GOT-NEXT: Initial: 0x30000
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# GOT-NEXT: Initial: 0x40000
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# ^-- (0x39000 + 0x8000) & ~0xffff
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# GOT-NEXT: }
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# GOT-NEXT: Entry {
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# GOT-NEXT: Address: 0x20010
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# GOT-NEXT: Access: -32736
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# GOT-NEXT: Initial: 0x30004
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# GOT-NEXT: Initial: 0x50000
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# ^-- (0x39000 + 0x10004 + 0x8000) & ~0xffff
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# ^-- (0x39000 + 0x18004 + 0x8000) & ~0xffff
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# GOT-NEXT: }
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# GOT-NEXT: Entry {
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# GOT-NEXT: Address: 0x20014
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# GOT-NEXT: Access: -32732
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# GOT-NEXT: Initial: 0x51008
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# ^-- 'bar' address
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# GOT-NEXT: }
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# GOT-NEXT: Entry {
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# GOT-NEXT: Address: 0x20018
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# GOT-NEXT: Access: -32728
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# GOT-NEXT: Initial: 0x0
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# ^-- redundant unused entry
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# GOT-NEXT: }
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# GOT-NEXT: ]
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# GOT-NEXT: Global entries [
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# GOT-NEXT: Entry {
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# GOT-NEXT: Address: 0x20014
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# GOT-NEXT: Access: -32732
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# GOT-NEXT: Address: 0x2001C
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# GOT-NEXT: Access: -32724
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# GOT-NEXT: Initial: 0x0
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# GOT-NEXT: Value: 0x0
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# GOT-NEXT: Type: None
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@ -80,6 +100,10 @@ __start:
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addi $t0,$t0,%lo($LC0)
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lw $t0,%got($LC1)($gp)
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addi $t0,$t0,%lo($LC1)
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lw $t0,%got($LC1+0x10004)($gp)
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addi $t0,$t0,%lo($LC1+0x10004)
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lw $t0,%got($LC1+0x18004)($gp)
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addi $t0,$t0,%lo($LC1+0x18004)
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lw $t0,%got(bar)($gp)
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addi $t0,$t0,%lo(bar)
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lw $t0,%got(foo)($gp)
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@ -87,8 +111,11 @@ $LC0:
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nop
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.data
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.space 0x9000
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$LC1:
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.word 0
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.space 0x18000
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.word 0
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.global bar
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.hidden bar
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bar:
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