forked from OSchip/llvm-project
[mips][mc] Emit R_{MICRO}MIPS_JALR when expanding jal to jalr
When replacing jal with jalr, also emit '.reloc R_MIPS_JALR' (R_MICROMIPS_JALR for micromips). The linker might then be able to turn jalr into a direct call. Add '-mips-jalr-reloc' to enable/disable this feature (default is true). Differential revision: https://reviews.llvm.org/D55292 llvm-svn: 348760
This commit is contained in:
Vladimir Stefanovic
parent
753efe3584
commit
4433f93afe
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@ -39,6 +39,7 @@
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#include "llvm/MC/MCValue.h"
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#include "llvm/MC/SubtargetFeature.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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@ -64,6 +65,11 @@ class MCInstrInfo;
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} // end namespace llvm
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static cl::opt<bool>
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EmitJalrReloc("mips-jalr-reloc", cl::Hidden,
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cl::desc("MIPS: Emit R_{MICRO}MIPS_JALR relocation with jalr"),
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cl::init(true));
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namespace {
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class MipsAssemblerOptions {
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@ -2065,9 +2071,21 @@ bool MipsAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
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JalrInst.addOperand(MCOperand::createReg(Mips::RA));
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JalrInst.addOperand(MCOperand::createReg(Mips::T9));
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// FIXME: Add an R_(MICRO)MIPS_JALR relocation after the JALR.
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// This relocation is supposed to be an optimization hint for the linker
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// and is not necessary for correctness.
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if (EmitJalrReloc) {
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// As an optimization hint for the linker, before the JALR we add:
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// .reloc tmplabel, R_{MICRO}MIPS_JALR, symbol
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// tmplabel:
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MCSymbol *TmpLabel = getContext().createTempSymbol();
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const MCExpr *TmpExpr = MCSymbolRefExpr::create(TmpLabel, getContext());
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const MCExpr *RelocJalrExpr =
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MCSymbolRefExpr::create(JalSym, MCSymbolRefExpr::VK_None,
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getContext(), IDLoc);
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TOut.getStreamer().EmitRelocDirective(*TmpExpr,
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inMicroMipsMode() ? "R_MICROMIPS_JALR" : "R_MIPS_JALR",
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RelocJalrExpr, IDLoc, *STI);
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TOut.getStreamer().EmitLabel(TmpLabel);
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}
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Inst = JalrInst;
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ExpandedJalSym = true;
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@ -40,27 +40,38 @@ local_label:
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# O32: # fixup A - offset: 0, value: %got(local_label), kind: fixup_Mips_GOT
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# O32: addiu $25, $25, %lo(local_label) # encoding: [0x27,0x39,A,A]
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# O32: # fixup A - offset: 0, value: %lo(local_label), kind: fixup_Mips_LO16
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# O32-NEXT: .reloc ($tmp0), R_MIPS_JALR, local_label
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# ELF-O32: 8f 99 00 00 lw $25, 0($gp)
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# ELF-O32-NEXT: R_MIPS_GOT16 .text
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# ELF-O32-NEXT: 27 39 00 00 addiu $25, $25, 0
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# ELF-O32-NEXT: R_MIPS_LO16 .text
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# ELF-O32-NEXT: 03 20 f8 09 jalr $25
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# ELF-O32-NEXT: R_MIPS_JALR local_label
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# N32: lw $25, %got_disp(local_label)($gp) # encoding: [0x8f,0x99,A,A]
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# N32: # fixup A - offset: 0, value: %got_disp(local_label), kind: fixup_Mips_GOT_DISP
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# N32-NEXT: .reloc ($tmp0), R_MIPS_JALR, local_label
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# ELF-N32: 8f 99 00 00 lw $25, 0($gp)
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# ELF-N32-NEXT: R_MIPS_GOT_DISP local_label
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# ELF-N32-NEXT: 03 20 f8 09 jalr $25
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# ELF-N32-NEXT: R_MIPS_JALR local_label
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# N64: ld $25, %got_disp(local_label)($gp) # encoding: [0xdf,0x99,A,A]
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# N64: # fixup A - offset: 0, value: %got_disp(local_label), kind: fixup_Mips_GOT_DISP
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# N64-NEXT: .reloc .Ltmp0, R_MIPS_JALR, local_label
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# ELF-N64: df 99 00 00 ld $25, 0($gp)
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# ELF-N64-NEXT: R_MIPS_GOT_DISP/R_MIPS_NONE/R_MIPS_NONE local_label
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# ELF-N64-NEXT: 03 20 f8 09 jalr $25
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# ELF-N64-NEXT: R_MIPS_JALR/R_MIPS_NONE/R_MIPS_NONE local_label
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# O32-MM: lw $25, %got(local_label)($gp) # encoding: [0xff,0x3c,A,A]
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# O32-MM: # fixup A - offset: 0, value: %got(local_label), kind: fixup_MICROMIPS_GOT16
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# O32-MM: addiu $25, $25, %lo(local_label) # encoding: [0x33,0x39,A,A]
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# O32-MM: # fixup A - offset: 0, value: %lo(local_label), kind: fixup_MICROMIPS_LO16
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# O32-MM-NEXT: .reloc ($tmp0), R_MICROMIPS_JALR, local_label
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# MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09]
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# MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c]
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@ -72,24 +83,34 @@ local_label:
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# Expanding "jal weak_label":
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# O32: lw $25, %call16(weak_label)($gp) # encoding: [0x8f,0x99,A,A]
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# O32: # fixup A - offset: 0, value: %call16(weak_label), kind: fixup_Mips_CALL16
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# O32-NEXT: .reloc ($tmp1), R_MIPS_JALR, weak_label
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# ELF-O32: 8f 99 00 00 lw $25, 0($gp)
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# ELF-O32-NEXT: R_MIPS_CALL16 weak_label
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# ELF-O32-NEXT: 03 20 f8 09 jalr $25
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# ELF-O32-NEXT: R_MIPS_JALR weak_label
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# N32: lw $25, %call16(weak_label)($gp) # encoding: [0x8f,0x99,A,A]
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# N32: # fixup A - offset: 0, value: %call16(weak_label), kind: fixup_Mips_CALL16
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# N32-NEXT: .reloc ($tmp1), R_MIPS_JALR, weak_label
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# ELF-N32: 8f 99 00 00 lw $25, 0($gp)
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# ELF-N32-NEXT: R_MIPS_CALL16 weak_label
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# ELF-N32-NEXT: 03 20 f8 09 jalr $25
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# ELF-N32-NEXT: R_MIPS_JALR weak_label
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# N64: ld $25, %call16(weak_label)($gp) # encoding: [0xdf,0x99,A,A]
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# N64: # fixup A - offset: 0, value: %call16(weak_label), kind: fixup_Mips_CALL16
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# N64-NEXT: .reloc .Ltmp1, R_MIPS_JALR, weak_label
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# ELF-N64: df 99 00 00 ld $25, 0($gp)
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# ELF-N64-NEXT: R_MIPS_CALL16/R_MIPS_NONE/R_MIPS_NONE weak_label
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# ELF-N64-NEXT: 03 20 f8 09 jalr $25
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# ELF-N64-NEXT: R_MIPS_JALR/R_MIPS_NONE/R_MIPS_NONE weak_label
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# O32-MM: lw $25, %call16(weak_label)($gp) # encoding: [0xff,0x3c,A,A]
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# O32-MM: # fixup A - offset: 0, value: %call16(weak_label), kind: fixup_MICROMIPS_CALL16
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# O32-MM-NEXT: .reloc ($tmp1), R_MICROMIPS_JALR, weak_label
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# MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09]
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# MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c]
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@ -101,24 +122,34 @@ local_label:
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# Expanding "jal global_label":
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# O32: lw $25, %call16(global_label)($gp) # encoding: [0x8f,0x99,A,A]
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# O32: # fixup A - offset: 0, value: %call16(global_label), kind: fixup_Mips_CALL16
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# O32-NEXT: .reloc ($tmp2), R_MIPS_JALR, global_label
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# ELF-O32: 8f 99 00 00 lw $25, 0($gp)
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# ELF-O32-NEXT: R_MIPS_CALL16 global_label
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# ELF-O32-NEXT: 03 20 f8 09 jalr $25
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# ELF-O32-NEXT: R_MIPS_JALR global_label
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# N32: lw $25, %call16(global_label)($gp) # encoding: [0x8f,0x99,A,A]
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# N32: # fixup A - offset: 0, value: %call16(global_label), kind: fixup_Mips_CALL16
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# N32-NEXT: .reloc ($tmp2), R_MIPS_JALR, global_label
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# ELF-N32: 8f 99 00 00 lw $25, 0($gp)
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# ELF-N32-NEXT: R_MIPS_CALL16 global_label
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# ELF-N32-NEXT: 03 20 f8 09 jalr $25
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# ELF-N32-NEXT: R_MIPS_JALR global_label
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# N64: ld $25, %call16(global_label)($gp) # encoding: [0xdf,0x99,A,A]
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# N64: # fixup A - offset: 0, value: %call16(global_label), kind: fixup_Mips_CALL16
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# N64-NEXT: .reloc .Ltmp2, R_MIPS_JALR, global_label
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# ELF-N64: df 99 00 00 ld $25, 0($gp)
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# ELF-N64-NEXT: R_MIPS_CALL16/R_MIPS_NONE/R_MIPS_NONE global_label
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# ELF-N64-NEXT: 03 20 f8 09 jalr $25
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# ELF-N64-NEXT: R_MIPS_JALR/R_MIPS_NONE/R_MIPS_NONE global_label
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# O32-MM: lw $25, %call16(global_label)($gp) # encoding: [0xff,0x3c,A,A]
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# O32-MM: # fixup A - offset: 0, value: %call16(global_label), kind: fixup_MICROMIPS_CALL16
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# O32-MM-NEXT: .reloc ($tmp2), R_MICROMIPS_JALR, global_label
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# MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09]
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# MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c]
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@ -150,6 +181,7 @@ local_label:
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# O32-MM-NEXT: # fixup A - offset: 0, value: %got(.text), kind: fixup_MICROMIPS_GOT16
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# O32-MM-NEXT: addiu $25, $25, %lo(.text) # encoding: [0x33,0x39,A,A]
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# O32-MM-NEXT: # fixup A - offset: 0, value: %lo(.text), kind: fixup_MICROMIPS_LO16
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# O32-MM-NEXT: .reloc ($tmp3), R_MICROMIPS_JALR, .text
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# MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09]
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# MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c]
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@ -160,32 +192,36 @@ local_label:
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nop
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# Expanding "jal 1f":
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# O32: lw $25, %got($tmp0)($gp) # encoding: [0x8f,0x99,A,A]
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# O32: # fixup A - offset: 0, value: %got($tmp0), kind: fixup_Mips_GOT
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# O32: addiu $25, $25, %lo($tmp0) # encoding: [0x27,0x39,A,A]
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# O32: # fixup A - offset: 0, value: %lo($tmp0), kind: fixup_Mips_LO16
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# O32: lw $25, %got($tmp4)($gp) # encoding: [0x8f,0x99,A,A]
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# O32: # fixup A - offset: 0, value: %got($tmp4), kind: fixup_Mips_GOT
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# O32: addiu $25, $25, %lo($tmp4) # encoding: [0x27,0x39,A,A]
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# O32: # fixup A - offset: 0, value: %lo($tmp4), kind: fixup_Mips_LO16
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# O32-NEXT: .reloc ($tmp5), R_MIPS_JALR, ($tmp4)
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# ELF-O32: 8f 99 00 00 lw $25, 0($gp)
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# ELF-O32-NEXT: R_MIPS_GOT16 .text
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# ELF-O32-NEXT: 27 39 00 58 addiu $25, $25, 88
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# ELF-O32-NEXT: R_MIPS_LO16 .text
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# ELF-O32-NEXT: 03 20 f8 09 jalr $25
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# ELF-O32-NEXT: R_MIPS_JALR $tmp0
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# N32: lw $25, %got_disp($tmp0)($gp) # encoding: [0x8f,0x99,A,A]
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# N32: # fixup A - offset: 0, value: %got_disp($tmp0), kind: fixup_Mips_GOT_DISP
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# N32: lw $25, %got_disp($tmp4)($gp) # encoding: [0x8f,0x99,A,A]
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# N32: # fixup A - offset: 0, value: %got_disp($tmp4), kind: fixup_Mips_GOT_DISP
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# ELF-N32: 8f 99 00 00 lw $25, 0($gp)
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# ELF-N32-NEXT: R_MIPS_GOT_DISP .Ltmp0
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# N64: ld $25, %got_disp(.Ltmp0)($gp) # encoding: [0xdf,0x99,A,A]
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# N64: # fixup A - offset: 0, value: %got_disp(.Ltmp0), kind: fixup_Mips_GOT_DISP
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# N64: ld $25, %got_disp(.Ltmp4)($gp) # encoding: [0xdf,0x99,A,A]
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# N64: # fixup A - offset: 0, value: %got_disp(.Ltmp4), kind: fixup_Mips_GOT_DISP
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# ELF-N64: df 99 00 00 ld $25, 0($gp)
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# ELF-N64-NEXT: R_MIPS_GOT_DISP/R_MIPS_NONE/R_MIPS_NONE .Ltmp0
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# O32-MM: lw $25, %got($tmp0)($gp) # encoding: [0xff,0x3c,A,A]
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# O32-MM: # fixup A - offset: 0, value: %got($tmp0), kind: fixup_MICROMIPS_GOT16
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# O32-MM: addiu $25, $25, %lo($tmp0) # encoding: [0x33,0x39,A,A]
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# O32-MM: # fixup A - offset: 0, value: %lo($tmp0), kind: fixup_MICROMIPS_LO16
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# O32-MM: lw $25, %got($tmp4)($gp) # encoding: [0xff,0x3c,A,A]
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# O32-MM: # fixup A - offset: 0, value: %got($tmp4), kind: fixup_MICROMIPS_GOT16
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# O32-MM: addiu $25, $25, %lo($tmp4) # encoding: [0x33,0x39,A,A]
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# O32-MM: # fixup A - offset: 0, value: %lo($tmp4), kind: fixup_MICROMIPS_LO16
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# O32-MM-NEXT: .reloc ($tmp5), R_MICROMIPS_JALR, ($tmp4)
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# MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09]
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# MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c]
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@ -200,11 +236,14 @@ local_label:
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# O32-FIXME: # fixup A - offset: 0, value: %got(forward_local), kind: fixup_Mips_GOT
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# O32-FIXME: addiu $25, $25, %lo(forward_local) # encoding: [0x27,0x39,A,A]
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# O32-FIXME:: # fixup A - offset: 0, value: %lo(forward_local), kind: fixup_Mips_LO16
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# O32-FIXME: .reloc ($tmp6), R_MIPS_JALR, forward_local
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# ELF-O32: 8f 99 00 00 lw $25, 0($gp)
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# ELF-O32-NEXT: R_MIPS_GOT16 .text
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# ELF-O32-NEXT: 27 39 00 64 addiu $25, $25, 100
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# ELF-O32-NEXT: R_MIPS_LO16 .text
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# ELF-O32-NEXT: 03 20 f8 09 jalr $25
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# ELF-O32-NEXT: R_MIPS_JALR forward_local
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# N32-FIXME: lw $25, %got_disp(forward_local)($gp) # encoding: [0x8f,0x99,A,A]
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# N32-FIXME: # fixup A - offset: 0, value: %got_disp(forward_local), kind: fixup_Mips_GOT_DISP
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@ -222,6 +261,7 @@ local_label:
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# O32-MM-FIXME: # fixup A - offset: 0, value: %got(forward_local), kind: fixup_MICROMIPS_GOT16
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# O32-MM-FIXME: addiu $25, $25, %lo(forward_local) # encoding: [0x33,0x39,A,A]
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# O32-MM-FIXME: # fixup A - offset: 0, value: %lo(forward_local), kind: fixup_MICROMIPS_LO16
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# O32-MM-FIXME: .reloc ($tmp6), R_MIPS_JALR, forward_local
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# MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09]
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# MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c]
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