From 4433f93afe901ecd9cc85706ff9c41b79ccbc725 Mon Sep 17 00:00:00 2001 From: Vladimir Stefanovic Date: Mon, 10 Dec 2018 15:07:36 +0000 Subject: [PATCH] [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 --- llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp | 24 +++++++-- llvm/test/MC/Mips/expansion-jal-sym-pic.s | 64 +++++++++++++++++++----- 2 files changed, 73 insertions(+), 15 deletions(-) diff --git a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp index 79e0c00..78dfed6 100644 --- a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp +++ b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp @@ -39,6 +39,7 @@ #include "llvm/MC/MCValue.h" #include "llvm/MC/SubtargetFeature.h" #include "llvm/Support/Casting.h" +#include "llvm/Support/CommandLine.h" #include "llvm/Support/Compiler.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" @@ -64,6 +65,11 @@ class MCInstrInfo; } // end namespace llvm +static cl::opt +EmitJalrReloc("mips-jalr-reloc", cl::Hidden, + cl::desc("MIPS: Emit R_{MICRO}MIPS_JALR relocation with jalr"), + cl::init(true)); + namespace { class MipsAssemblerOptions { @@ -2065,9 +2071,21 @@ bool MipsAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc, JalrInst.addOperand(MCOperand::createReg(Mips::RA)); JalrInst.addOperand(MCOperand::createReg(Mips::T9)); - // FIXME: Add an R_(MICRO)MIPS_JALR relocation after the JALR. - // This relocation is supposed to be an optimization hint for the linker - // and is not necessary for correctness. + if (EmitJalrReloc) { + // As an optimization hint for the linker, before the JALR we add: + // .reloc tmplabel, R_{MICRO}MIPS_JALR, symbol + // tmplabel: + MCSymbol *TmpLabel = getContext().createTempSymbol(); + const MCExpr *TmpExpr = MCSymbolRefExpr::create(TmpLabel, getContext()); + const MCExpr *RelocJalrExpr = + MCSymbolRefExpr::create(JalSym, MCSymbolRefExpr::VK_None, + getContext(), IDLoc); + + TOut.getStreamer().EmitRelocDirective(*TmpExpr, + inMicroMipsMode() ? "R_MICROMIPS_JALR" : "R_MIPS_JALR", + RelocJalrExpr, IDLoc, *STI); + TOut.getStreamer().EmitLabel(TmpLabel); + } Inst = JalrInst; ExpandedJalSym = true; diff --git a/llvm/test/MC/Mips/expansion-jal-sym-pic.s b/llvm/test/MC/Mips/expansion-jal-sym-pic.s index dddd7aa..81584d4 100644 --- a/llvm/test/MC/Mips/expansion-jal-sym-pic.s +++ b/llvm/test/MC/Mips/expansion-jal-sym-pic.s @@ -40,27 +40,38 @@ local_label: # O32: # fixup A - offset: 0, value: %got(local_label), kind: fixup_Mips_GOT # O32: addiu $25, $25, %lo(local_label) # encoding: [0x27,0x39,A,A] # O32: # fixup A - offset: 0, value: %lo(local_label), kind: fixup_Mips_LO16 +# O32-NEXT: .reloc ($tmp0), R_MIPS_JALR, local_label + # ELF-O32: 8f 99 00 00 lw $25, 0($gp) # ELF-O32-NEXT: R_MIPS_GOT16 .text # ELF-O32-NEXT: 27 39 00 00 addiu $25, $25, 0 # ELF-O32-NEXT: R_MIPS_LO16 .text +# ELF-O32-NEXT: 03 20 f8 09 jalr $25 +# ELF-O32-NEXT: R_MIPS_JALR local_label # N32: lw $25, %got_disp(local_label)($gp) # encoding: [0x8f,0x99,A,A] # N32: # fixup A - offset: 0, value: %got_disp(local_label), kind: fixup_Mips_GOT_DISP +# N32-NEXT: .reloc ($tmp0), R_MIPS_JALR, local_label # ELF-N32: 8f 99 00 00 lw $25, 0($gp) # ELF-N32-NEXT: R_MIPS_GOT_DISP local_label +# ELF-N32-NEXT: 03 20 f8 09 jalr $25 +# ELF-N32-NEXT: R_MIPS_JALR local_label # N64: ld $25, %got_disp(local_label)($gp) # encoding: [0xdf,0x99,A,A] # N64: # fixup A - offset: 0, value: %got_disp(local_label), kind: fixup_Mips_GOT_DISP +# N64-NEXT: .reloc .Ltmp0, R_MIPS_JALR, local_label # ELF-N64: df 99 00 00 ld $25, 0($gp) # ELF-N64-NEXT: R_MIPS_GOT_DISP/R_MIPS_NONE/R_MIPS_NONE local_label +# ELF-N64-NEXT: 03 20 f8 09 jalr $25 +# ELF-N64-NEXT: R_MIPS_JALR/R_MIPS_NONE/R_MIPS_NONE local_label # O32-MM: lw $25, %got(local_label)($gp) # encoding: [0xff,0x3c,A,A] # O32-MM: # fixup A - offset: 0, value: %got(local_label), kind: fixup_MICROMIPS_GOT16 # O32-MM: addiu $25, $25, %lo(local_label) # encoding: [0x33,0x39,A,A] # O32-MM: # fixup A - offset: 0, value: %lo(local_label), kind: fixup_MICROMIPS_LO16 +# O32-MM-NEXT: .reloc ($tmp0), R_MICROMIPS_JALR, local_label # MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09] # MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c] @@ -72,24 +83,34 @@ local_label: # Expanding "jal weak_label": # O32: lw $25, %call16(weak_label)($gp) # encoding: [0x8f,0x99,A,A] # O32: # fixup A - offset: 0, value: %call16(weak_label), kind: fixup_Mips_CALL16 +# O32-NEXT: .reloc ($tmp1), R_MIPS_JALR, weak_label # ELF-O32: 8f 99 00 00 lw $25, 0($gp) # ELF-O32-NEXT: R_MIPS_CALL16 weak_label +# ELF-O32-NEXT: 03 20 f8 09 jalr $25 +# ELF-O32-NEXT: R_MIPS_JALR weak_label # N32: lw $25, %call16(weak_label)($gp) # encoding: [0x8f,0x99,A,A] # N32: # fixup A - offset: 0, value: %call16(weak_label), kind: fixup_Mips_CALL16 +# N32-NEXT: .reloc ($tmp1), R_MIPS_JALR, weak_label # ELF-N32: 8f 99 00 00 lw $25, 0($gp) # ELF-N32-NEXT: R_MIPS_CALL16 weak_label +# ELF-N32-NEXT: 03 20 f8 09 jalr $25 +# ELF-N32-NEXT: R_MIPS_JALR weak_label # N64: ld $25, %call16(weak_label)($gp) # encoding: [0xdf,0x99,A,A] # N64: # fixup A - offset: 0, value: %call16(weak_label), kind: fixup_Mips_CALL16 +# N64-NEXT: .reloc .Ltmp1, R_MIPS_JALR, weak_label # ELF-N64: df 99 00 00 ld $25, 0($gp) # ELF-N64-NEXT: R_MIPS_CALL16/R_MIPS_NONE/R_MIPS_NONE weak_label +# ELF-N64-NEXT: 03 20 f8 09 jalr $25 +# ELF-N64-NEXT: R_MIPS_JALR/R_MIPS_NONE/R_MIPS_NONE weak_label # O32-MM: lw $25, %call16(weak_label)($gp) # encoding: [0xff,0x3c,A,A] # O32-MM: # fixup A - offset: 0, value: %call16(weak_label), kind: fixup_MICROMIPS_CALL16 +# O32-MM-NEXT: .reloc ($tmp1), R_MICROMIPS_JALR, weak_label # MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09] # MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c] @@ -101,24 +122,34 @@ local_label: # Expanding "jal global_label": # O32: lw $25, %call16(global_label)($gp) # encoding: [0x8f,0x99,A,A] # O32: # fixup A - offset: 0, value: %call16(global_label), kind: fixup_Mips_CALL16 +# O32-NEXT: .reloc ($tmp2), R_MIPS_JALR, global_label # ELF-O32: 8f 99 00 00 lw $25, 0($gp) # ELF-O32-NEXT: R_MIPS_CALL16 global_label +# ELF-O32-NEXT: 03 20 f8 09 jalr $25 +# ELF-O32-NEXT: R_MIPS_JALR global_label # N32: lw $25, %call16(global_label)($gp) # encoding: [0x8f,0x99,A,A] # N32: # fixup A - offset: 0, value: %call16(global_label), kind: fixup_Mips_CALL16 +# N32-NEXT: .reloc ($tmp2), R_MIPS_JALR, global_label # ELF-N32: 8f 99 00 00 lw $25, 0($gp) # ELF-N32-NEXT: R_MIPS_CALL16 global_label +# ELF-N32-NEXT: 03 20 f8 09 jalr $25 +# ELF-N32-NEXT: R_MIPS_JALR global_label # N64: ld $25, %call16(global_label)($gp) # encoding: [0xdf,0x99,A,A] # N64: # fixup A - offset: 0, value: %call16(global_label), kind: fixup_Mips_CALL16 +# N64-NEXT: .reloc .Ltmp2, R_MIPS_JALR, global_label # ELF-N64: df 99 00 00 ld $25, 0($gp) # ELF-N64-NEXT: R_MIPS_CALL16/R_MIPS_NONE/R_MIPS_NONE global_label +# ELF-N64-NEXT: 03 20 f8 09 jalr $25 +# ELF-N64-NEXT: R_MIPS_JALR/R_MIPS_NONE/R_MIPS_NONE global_label # O32-MM: lw $25, %call16(global_label)($gp) # encoding: [0xff,0x3c,A,A] # O32-MM: # fixup A - offset: 0, value: %call16(global_label), kind: fixup_MICROMIPS_CALL16 +# O32-MM-NEXT: .reloc ($tmp2), R_MICROMIPS_JALR, global_label # MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09] # MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c] @@ -150,6 +181,7 @@ local_label: # O32-MM-NEXT: # fixup A - offset: 0, value: %got(.text), kind: fixup_MICROMIPS_GOT16 # O32-MM-NEXT: addiu $25, $25, %lo(.text) # encoding: [0x33,0x39,A,A] # O32-MM-NEXT: # fixup A - offset: 0, value: %lo(.text), kind: fixup_MICROMIPS_LO16 +# O32-MM-NEXT: .reloc ($tmp3), R_MICROMIPS_JALR, .text # MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09] # MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c] @@ -160,32 +192,36 @@ local_label: nop # Expanding "jal 1f": -# O32: lw $25, %got($tmp0)($gp) # encoding: [0x8f,0x99,A,A] -# O32: # fixup A - offset: 0, value: %got($tmp0), kind: fixup_Mips_GOT -# O32: addiu $25, $25, %lo($tmp0) # encoding: [0x27,0x39,A,A] -# O32: # fixup A - offset: 0, value: %lo($tmp0), kind: fixup_Mips_LO16 +# O32: lw $25, %got($tmp4)($gp) # encoding: [0x8f,0x99,A,A] +# O32: # fixup A - offset: 0, value: %got($tmp4), kind: fixup_Mips_GOT +# O32: addiu $25, $25, %lo($tmp4) # encoding: [0x27,0x39,A,A] +# O32: # fixup A - offset: 0, value: %lo($tmp4), kind: fixup_Mips_LO16 +# O32-NEXT: .reloc ($tmp5), R_MIPS_JALR, ($tmp4) # ELF-O32: 8f 99 00 00 lw $25, 0($gp) # ELF-O32-NEXT: R_MIPS_GOT16 .text # ELF-O32-NEXT: 27 39 00 58 addiu $25, $25, 88 # ELF-O32-NEXT: R_MIPS_LO16 .text +# ELF-O32-NEXT: 03 20 f8 09 jalr $25 +# ELF-O32-NEXT: R_MIPS_JALR $tmp0 -# N32: lw $25, %got_disp($tmp0)($gp) # encoding: [0x8f,0x99,A,A] -# N32: # fixup A - offset: 0, value: %got_disp($tmp0), kind: fixup_Mips_GOT_DISP +# N32: lw $25, %got_disp($tmp4)($gp) # encoding: [0x8f,0x99,A,A] +# N32: # fixup A - offset: 0, value: %got_disp($tmp4), kind: fixup_Mips_GOT_DISP # ELF-N32: 8f 99 00 00 lw $25, 0($gp) # ELF-N32-NEXT: R_MIPS_GOT_DISP .Ltmp0 -# N64: ld $25, %got_disp(.Ltmp0)($gp) # encoding: [0xdf,0x99,A,A] -# N64: # fixup A - offset: 0, value: %got_disp(.Ltmp0), kind: fixup_Mips_GOT_DISP +# N64: ld $25, %got_disp(.Ltmp4)($gp) # encoding: [0xdf,0x99,A,A] +# N64: # fixup A - offset: 0, value: %got_disp(.Ltmp4), kind: fixup_Mips_GOT_DISP # ELF-N64: df 99 00 00 ld $25, 0($gp) # ELF-N64-NEXT: R_MIPS_GOT_DISP/R_MIPS_NONE/R_MIPS_NONE .Ltmp0 -# O32-MM: lw $25, %got($tmp0)($gp) # encoding: [0xff,0x3c,A,A] -# O32-MM: # fixup A - offset: 0, value: %got($tmp0), kind: fixup_MICROMIPS_GOT16 -# O32-MM: addiu $25, $25, %lo($tmp0) # encoding: [0x33,0x39,A,A] -# O32-MM: # fixup A - offset: 0, value: %lo($tmp0), kind: fixup_MICROMIPS_LO16 +# O32-MM: lw $25, %got($tmp4)($gp) # encoding: [0xff,0x3c,A,A] +# O32-MM: # fixup A - offset: 0, value: %got($tmp4), kind: fixup_MICROMIPS_GOT16 +# O32-MM: addiu $25, $25, %lo($tmp4) # encoding: [0x33,0x39,A,A] +# O32-MM: # fixup A - offset: 0, value: %lo($tmp4), kind: fixup_MICROMIPS_LO16 +# O32-MM-NEXT: .reloc ($tmp5), R_MICROMIPS_JALR, ($tmp4) # MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09] # MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c] @@ -200,11 +236,14 @@ local_label: # O32-FIXME: # fixup A - offset: 0, value: %got(forward_local), kind: fixup_Mips_GOT # O32-FIXME: addiu $25, $25, %lo(forward_local) # encoding: [0x27,0x39,A,A] # O32-FIXME:: # fixup A - offset: 0, value: %lo(forward_local), kind: fixup_Mips_LO16 +# O32-FIXME: .reloc ($tmp6), R_MIPS_JALR, forward_local # ELF-O32: 8f 99 00 00 lw $25, 0($gp) # ELF-O32-NEXT: R_MIPS_GOT16 .text # ELF-O32-NEXT: 27 39 00 64 addiu $25, $25, 100 # ELF-O32-NEXT: R_MIPS_LO16 .text +# ELF-O32-NEXT: 03 20 f8 09 jalr $25 +# ELF-O32-NEXT: R_MIPS_JALR forward_local # N32-FIXME: lw $25, %got_disp(forward_local)($gp) # encoding: [0x8f,0x99,A,A] # N32-FIXME: # fixup A - offset: 0, value: %got_disp(forward_local), kind: fixup_Mips_GOT_DISP @@ -222,6 +261,7 @@ local_label: # O32-MM-FIXME: # fixup A - offset: 0, value: %got(forward_local), kind: fixup_MICROMIPS_GOT16 # O32-MM-FIXME: addiu $25, $25, %lo(forward_local) # encoding: [0x33,0x39,A,A] # O32-MM-FIXME: # fixup A - offset: 0, value: %lo(forward_local), kind: fixup_MICROMIPS_LO16 +# O32-MM-FIXME: .reloc ($tmp6), R_MIPS_JALR, forward_local # MIPS: jalr $25 # encoding: [0x03,0x20,0xf8,0x09] # MM: jalr $ra, $25 # encoding: [0x03,0xf9,0x0f,0x3c] -- 2.7.4