diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst --- a/clang/docs/UsersManual.rst +++ b/clang/docs/UsersManual.rst @@ -1700,9 +1700,12 @@ **-fbasic-block-sections=[labels, all, list=, none]** - Controls whether Clang emits a label for each basic block. Further, with - values "all" and "list=arg", each basic block or a subset of basic blocks - can be placed in its own unique section. + Controls how Clang emits text sections for basic blocks. With values ``all`` + and ``list=``, each basic block or a subset of basic blocks can be placed + in its own unique section. With the "labels" value, normal text sections are + emitted, but a ``.bb_addr_map`` section is emitted which includes address + offsets for each basic block in the program, relative to the parent function + address. With the ``list=`` option, a file containing the subset of basic blocks that need to placed in unique sections can be specified. The format of the diff --git a/clang/test/CodeGen/basic-block-sections.c b/clang/test/CodeGen/basic-block-sections.c --- a/clang/test/CodeGen/basic-block-sections.c +++ b/clang/test/CodeGen/basic-block-sections.c @@ -1,12 +1,11 @@ // REQUIRES: x86-registered-target -// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -S -o - < %s | FileCheck %s --check-prefix=PLAIN -// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -S -fbasic-block-sections=all -fbasic-block-sections=none -o - < %s | FileCheck %s --check-prefix=PLAIN +// RUN: %clang_cc1 -triple x86_64 -S -o - < %s | FileCheck %s --check-prefix=PLAIN +// RUN: %clang_cc1 -triple x86_64 -S -fbasic-block-sections=all -fbasic-block-sections=none -o - < %s | FileCheck %s --check-prefix=PLAIN -// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -S -fbasic-block-sections=labels -o - < %s | FileCheck %s --check-prefix=BB_LABELS -// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -S -fbasic-block-sections=all -o - < %s | FileCheck %s --check-prefix=BB_WORLD --check-prefix=BB_ALL -// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -S -fbasic-block-sections=list=%S/Inputs/basic-block-sections.funcnames -o - < %s | FileCheck %s --check-prefix=BB_WORLD --check-prefix=BB_LIST -// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -S -fbasic-block-sections=all -funique-basic-block-section-names -o - < %s | FileCheck %s --check-prefix=UNIQUE +// RUN: %clang_cc1 -triple x86_64 -S -fbasic-block-sections=all -o - < %s | FileCheck %s --check-prefix=BB_WORLD --check-prefix=BB_ALL +// RUN: %clang_cc1 -triple x86_64 -S -fbasic-block-sections=list=%S/Inputs/basic-block-sections.funcnames -o - < %s | FileCheck %s --check-prefix=BB_WORLD --check-prefix=BB_LIST +// RUN: %clang_cc1 -triple x86_64 -S -fbasic-block-sections=all -funique-basic-block-section-names -o - < %s | FileCheck %s --check-prefix=UNIQUE int world(int a) { if (a > 10) @@ -26,12 +25,6 @@ // PLAIN-NOT: section // PLAIN: world: // -// BB_LABELS-NOT: section -// BB_LABELS: world: -// BB_LABELS: a.BB.world: -// BB_LABELS: aa.BB.world: -// BB_LABELS: a.BB.another: -// // BB_WORLD: .section .text.world,"ax",@progbits{{$}} // BB_WORLD: world: // BB_WORLD: .section .text.world,"ax",@progbits,unique diff --git a/llvm/include/llvm/CodeGen/AsmPrinter.h b/llvm/include/llvm/CodeGen/AsmPrinter.h --- a/llvm/include/llvm/CodeGen/AsmPrinter.h +++ b/llvm/include/llvm/CodeGen/AsmPrinter.h @@ -342,6 +342,8 @@ void emitStackSizeSection(const MachineFunction &MF); + void emitBBAddrMapSection(const MachineFunction &MF); + void emitRemarksSection(remarks::RemarkStreamer &RS); enum CFIMoveType { CFI_M_None, CFI_M_EH, CFI_M_Debug }; diff --git a/llvm/include/llvm/CodeGen/MachineFunction.h b/llvm/include/llvm/CodeGen/MachineFunction.h --- a/llvm/include/llvm/CodeGen/MachineFunction.h +++ b/llvm/include/llvm/CodeGen/MachineFunction.h @@ -505,9 +505,6 @@ void setBBSectionsType(BasicBlockSection V) { BBSectionsType = V; } - /// Creates basic block Labels for this function. - void createBBLabels(); - /// Assign IsBeginSection IsEndSection fields for basic blocks in this /// function. void assignBeginEndSections(); diff --git a/llvm/include/llvm/MC/MCObjectFileInfo.h b/llvm/include/llvm/MC/MCObjectFileInfo.h --- a/llvm/include/llvm/MC/MCObjectFileInfo.h +++ b/llvm/include/llvm/MC/MCObjectFileInfo.h @@ -338,6 +338,8 @@ MCSection *getStackSizesSection(const MCSection &TextSec) const; + MCSection *getBBAddrMapSection(const MCSection &TextSec) const; + // ELF specific sections. MCSection *getDataRelROSection() const { return DataRelROSection; } const MCSection *getMergeableConst4Section() const { diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp --- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp +++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp @@ -1023,6 +1023,46 @@ MCConstantExpr::create(FrameOffset, OutContext)); } +/// Returns the BB metadata to be emitted in the bb_addr_map section for a given +/// basic block. This can be used to capture more precise profile information. +/// We use the last 3 bits (LSBs) to ecnode the following information: +/// * (1): set if return block (ret or tail call). +/// * (2): set if ends with a tail call. +/// * (3): set if exception handling (EH) landing pad. +/// The remaining bits are zero. +static unsigned getBBAddrMapMetadata(const MachineBasicBlock &MBB) { + const TargetInstrInfo *TII = MBB.getParent()->getSubtarget().getInstrInfo(); + return ((unsigned)MBB.isReturnBlock()) | + ((!MBB.empty() && TII->isTailCall(MBB.back())) << 1) | + (MBB.isEHPad() << 2); +} + +void AsmPrinter::emitBBAddrMapSection(const MachineFunction &MF) { + MCSection *BBAddrMapSection = + getObjFileLowering().getBBAddrMapSection(*MF.getSection()); + assert(BBAddrMapSection && ".bb_addr_map section is not initialized."); + + const MCSymbol *FunctionSymbol = getFunctionBegin(); + + OutStreamer->PushSection(); + OutStreamer->SwitchSection(BBAddrMapSection); + OutStreamer->emitSymbolValue(FunctionSymbol, getPointerSize()); + // Emit the total number of basic blocks in this function. + OutStreamer->emitULEB128IntValue(MF.size()); + // Emit BB Information for each basic block in the funciton. + for (const MachineBasicBlock &MBB : MF) { + const MCSymbol *MBBSymbol = + MBB.pred_empty() ? FunctionSymbol : MBB.getSymbol(); + // Emit the basic block offset. + emitLabelDifferenceAsULEB128(MBBSymbol, FunctionSymbol); + // Emit the basic block size. When BBs have alignments, their size cannot + // always be computed from their offsets. + emitLabelDifferenceAsULEB128(MBB.getEndSymbol(), MBBSymbol); + OutStreamer->emitULEB128IntValue(getBBAddrMapMetadata(MBB)); + } + OutStreamer->PopSection(); +} + void AsmPrinter::emitStackSizeSection(const MachineFunction &MF) { if (!MF.getTarget().Options.EmitStackSizeSection) return; @@ -1174,34 +1214,26 @@ } // We must emit temporary symbol for the end of this basic block, if either - // we have BBLabels enabled and we want to emit size directive for the BBs, - // or if this basic blocks marks the end of a section (except the section - // containing the entry basic block as the end symbol for that section is - // CurrentFnEnd). - if ((MAI->hasDotTypeDotSizeDirective() && MF->hasBBLabels()) || - (MBB.isEndSection() && !MBB.sameSection(&MF->front()))) + // we have BBLabels enabled or if this basic blocks marks the end of a + // section (except the section containing the entry basic block as the end + // symbol for that section is CurrentFnEnd). + if (MF->hasBBLabels() || + (MAI->hasDotTypeDotSizeDirective() && MBB.isEndSection() && + !MBB.sameSection(&MF->front()))) OutStreamer->emitLabel(MBB.getEndSymbol()); - // Helper for emitting the size directive associated with a basic block - // symbol. - auto emitELFSizeDirective = [&](MCSymbol *SymForSize) { - const MCExpr *SizeExp = MCBinaryExpr::createSub( - MCSymbolRefExpr::create(MBB.getEndSymbol(), OutContext), - MCSymbolRefExpr::create(SymForSize, OutContext), OutContext); - OutStreamer->emitELFSize(SymForSize, SizeExp); - }; - - // Emit size directive for the size of each basic block, if BBLabels is - // enabled. - if (MAI->hasDotTypeDotSizeDirective() && MF->hasBBLabels()) - emitELFSizeDirective(MBB.getSymbol()); - - // Emit size directive for the size of each basic block section once we - // get to the end of that section. if (MBB.isEndSection()) { + // The size directive for the section containing the entry block is + // handled separately by the function section. if (!MBB.sameSection(&MF->front())) { - if (MAI->hasDotTypeDotSizeDirective()) - emitELFSizeDirective(CurrentSectionBeginSym); + if (MAI->hasDotTypeDotSizeDirective()) { + // Emit the size directive for the basic block section. + const MCExpr *SizeExp = MCBinaryExpr::createSub( + MCSymbolRefExpr::create(MBB.getEndSymbol(), OutContext), + MCSymbolRefExpr::create(CurrentSectionBeginSym, OutContext), + OutContext); + OutStreamer->emitELFSize(CurrentSectionBeginSym, SizeExp); + } MBBSectionRanges[MBB.getSectionIDNum()] = MBBSectionRange{CurrentSectionBeginSym, MBB.getEndSymbol()}; } @@ -1293,6 +1325,11 @@ HI.Handler->endFunction(MF); } + // Emit section containing BB address offsets and their metadata, when + // BB labels are requested for this function. + if (MF->hasBBLabels()) + emitBBAddrMapSection(*MF); + // Emit section containing stack size metadata. emitStackSizeSection(*MF); @@ -1802,7 +1839,7 @@ F.hasFnAttribute("function-instrument") || F.hasFnAttribute("xray-instruction-threshold") || needFuncLabelsForEHOrDebugInfo(MF) || NeedsLocalForSize || - MF.getTarget().Options.EmitStackSizeSection) { + MF.getTarget().Options.EmitStackSizeSection || MF.hasBBLabels()) { CurrentFnBegin = createTempSymbol("func_begin"); if (NeedsLocalForSize) CurrentFnSymForSize = CurrentFnBegin; diff --git a/llvm/lib/CodeGen/BasicBlockSections.cpp b/llvm/lib/CodeGen/BasicBlockSections.cpp --- a/llvm/lib/CodeGen/BasicBlockSections.cpp +++ b/llvm/lib/CodeGen/BasicBlockSections.cpp @@ -48,19 +48,11 @@ // Basic Block Labels // ================== // -// With -fbasic-block-sections=labels, or when a basic block is placed in a -// unique section, it is labelled with a symbol. This allows easy mapping of -// virtual addresses from PMU profiles back to the corresponding basic blocks. -// Since the number of basic blocks is large, the labeling bloats the symbol -// table sizes and the string table sizes significantly. While the binary size -// does increase, it does not affect performance as the symbol table is not -// loaded in memory during run-time. The string table size bloat is kept very -// minimal using a unary naming scheme that uses string suffix compression. The -// basic blocks for function foo are named "a.BB.foo", "aa.BB.foo", ... This -// turns out to be very good for string table sizes and the bloat in the string -// table size for a very large binary is ~8 %. The naming also allows using -// the --symbol-ordering-file option in LLD to arbitrarily reorder the -// sections. +// With -fbasic-block-sections=labels, we emit the offsets of BB addresses of +// every function into a .bb_addr_map section. Along with the function symbols, +// this allows for mapping of virtual addresses in PMU profiles back to the +// corresponding basic blocks. This logic is implemented in AsmPrinter. This +// pass only assigns the BBSectionType of every function to ``labels``. // //===----------------------------------------------------------------------===// @@ -304,7 +296,6 @@ if (BBSectionsType == BasicBlockSection::Labels) { MF.setBBSectionsType(BBSectionsType); - MF.createBBLabels(); return true; } @@ -314,7 +305,6 @@ FuncBBClusterInfo)) return true; MF.setBBSectionsType(BBSectionsType); - MF.createBBLabels(); assignSections(MF, FuncBBClusterInfo); // We make sure that the cluster including the entry basic block precedes all diff --git a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp --- a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp +++ b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp @@ -451,10 +451,8 @@ } // Check Basic Block Section Flags. if (MF.getTarget().getBBSectionsType() == BasicBlockSection::Labels) { - MF.createBBLabels(); MF.setBBSectionsType(BasicBlockSection::Labels); } else if (MF.hasBBSections()) { - MF.createBBLabels(); MF.assignBeginEndSections(); } PFS.SM = &SM; diff --git a/llvm/lib/CodeGen/MachineBasicBlock.cpp b/llvm/lib/CodeGen/MachineBasicBlock.cpp --- a/llvm/lib/CodeGen/MachineBasicBlock.cpp +++ b/llvm/lib/CodeGen/MachineBasicBlock.cpp @@ -60,28 +60,11 @@ if (!CachedMCSymbol) { const MachineFunction *MF = getParent(); MCContext &Ctx = MF->getContext(); - auto Prefix = Ctx.getAsmInfo()->getPrivateLabelPrefix(); - assert(getNumber() >= 0 && "cannot get label for unreachable MBB"); - - // We emit a non-temporary symbol for every basic block if we have BBLabels - // or -- with basic block sections -- when a basic block begins a section. - // With basic block symbols, we use a unary encoding which can - // compress the symbol names significantly. For basic block sections where - // this block is the first in a cluster, we use a non-temp descriptive name. - // Otherwise we fall back to use temp label. - if (MF->hasBBLabels()) { - auto Iter = MF->getBBSectionsSymbolPrefix().begin(); - if (getNumber() < 0 || - getNumber() >= (int)MF->getBBSectionsSymbolPrefix().size()) - report_fatal_error("Unreachable MBB: " + Twine(getNumber())); - // The basic blocks for function foo are named a.BB.foo, aa.BB.foo, and - // so on. - std::string Prefix(Iter + 1, Iter + getNumber() + 1); - std::reverse(Prefix.begin(), Prefix.end()); - CachedMCSymbol = - Ctx.getOrCreateSymbol(Twine(Prefix) + ".BB." + Twine(MF->getName())); - } else if (MF->hasBBSections() && isBeginSection()) { + // We emit a non-temporary symbol -- with a descriptive name -- if it begins + // a section (with basic block sections). Otherwise we fall back to use temp + // label. + if (MF->hasBBSections() && isBeginSection()) { SmallString<5> Suffix; if (SectionID == MBBSectionID::ColdSectionID) { Suffix += ".cold"; @@ -92,6 +75,7 @@ } CachedMCSymbol = Ctx.getOrCreateSymbol(MF->getName() + Suffix); } else { + const StringRef Prefix = Ctx.getAsmInfo()->getPrivateLabelPrefix(); CachedMCSymbol = Ctx.getOrCreateSymbol(Twine(Prefix) + "BB" + Twine(MF->getFunctionNumber()) + "_" + Twine(getNumber())); diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp --- a/llvm/lib/CodeGen/MachineFunction.cpp +++ b/llvm/lib/CodeGen/MachineFunction.cpp @@ -341,33 +341,6 @@ MBBNumbering.resize(BlockNo); } -/// This is used with -fbasic-block-sections or -fbasicblock-labels option. -/// A unary encoding of basic block labels is done to keep ".strtab" sizes -/// small. -void MachineFunction::createBBLabels() { - const TargetInstrInfo *TII = getSubtarget().getInstrInfo(); - this->BBSectionsSymbolPrefix.resize(getNumBlockIDs(), 'a'); - for (auto MBBI = begin(), E = end(); MBBI != E; ++MBBI) { - assert( - (MBBI->getNumber() >= 0 && MBBI->getNumber() < (int)getNumBlockIDs()) && - "BasicBlock number was out of range!"); - // 'a' - Normal block. - // 'r' - Return block. - // 'l' - Landing Pad. - // 'L' - Return and landing pad. - bool isEHPad = MBBI->isEHPad(); - bool isRetBlock = MBBI->isReturnBlock() && !TII->isTailCall(MBBI->back()); - char type = 'a'; - if (isEHPad && isRetBlock) - type = 'L'; - else if (isEHPad) - type = 'l'; - else if (isRetBlock) - type = 'r'; - BBSectionsSymbolPrefix[MBBI->getNumber()] = type; - } -} - /// This method iterates over the basic blocks and assigns their IsBeginSection /// and IsEndSection fields. This must be called after MBB layout is finalized /// and the SectionID's are assigned to MBBs. diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp --- a/llvm/lib/MC/MCObjectFileInfo.cpp +++ b/llvm/lib/MC/MCObjectFileInfo.cpp @@ -953,3 +953,21 @@ GroupName, MCSection::NonUniqueID, cast(TextSec.getBeginSymbol())); } + +MCSection * +MCObjectFileInfo::getBBAddrMapSection(const MCSection &TextSec) const { + if (Env != IsELF) + return nullptr; + + const MCSectionELF &ElfSec = static_cast(TextSec); + unsigned Flags = ELF::SHF_LINK_ORDER; + StringRef GroupName; + if (const MCSymbol *Group = ElfSec.getGroup()) { + GroupName = Group->getName(); + Flags |= ELF::SHF_GROUP; + } + + return Ctx->getELFSection(".bb_addr_map", ELF::SHT_PROGBITS, Flags, 0, + GroupName, MCSection::NonUniqueID, + cast(TextSec.getBeginSymbol())); +} diff --git a/llvm/test/CodeGen/X86/basic-block-sections-labels-functions-sections.ll b/llvm/test/CodeGen/X86/basic-block-sections-labels-functions-sections.ll new file mode 100644 --- /dev/null +++ b/llvm/test/CodeGen/X86/basic-block-sections-labels-functions-sections.ll @@ -0,0 +1,35 @@ +; RUN: llc < %s -mtriple=x86_64 -function-sections -basic-block-sections=labels | FileCheck %s + +$_Z4fooTIiET_v = comdat any + +define dso_local i32 @_Z3barv() { + ret i32 0 +} +;; Check we add SHF_LINK_ORDER for .bb_addr_map and link it with the corresponding .text sections. +; CHECK: .section .text._Z3barv,"ax",@progbits +; CHECK-LABEL: _Z3barv: +; CHECK-NEXT: [[BAR_BEGIN:.Lfunc_begin[0-9]+]]: +; CHECK: .section .bb_addr_map,"o",@progbits,.text._Z3barv{{$}} +; CHECK-NEXT: .quad [[BAR_BEGIN]] + + +define dso_local i32 @_Z3foov() { + %1 = call i32 @_Z4fooTIiET_v() + ret i32 %1 +} +; CHECK: .section .text._Z3foov,"ax",@progbits +; CHECK-LABEL: _Z3foov: +; CHECK-NEXT: [[FOO_BEGIN:.Lfunc_begin[0-9]+]]: +; CHECK: .section .bb_addr_map,"o",@progbits,.text._Z3foov{{$}} +; CHECK-NEXT: .quad [[FOO_BEGIN]] + + +define linkonce_odr dso_local i32 @_Z4fooTIiET_v() comdat { + ret i32 0 +} +;; Check we add .bb_addr_map section to a COMDAT group with the corresponding .text section if such a COMDAT exists. +; CHECK: .section .text._Z4fooTIiET_v,"axG",@progbits,_Z4fooTIiET_v,comdat +; CHECK-LABEL: _Z4fooTIiET_v: +; CHECK-NEXT: [[FOOCOMDAT_BEGIN:.Lfunc_begin[0-9]+]]: +; CHECK: .section .bb_addr_map,"Go",@progbits,_Z4fooTIiET_v,comdat,.text._Z4fooTIiET_v{{$}} +; CHECK-NEXT: .quad [[FOOCOMDAT_BEGIN]] diff --git a/llvm/test/CodeGen/X86/basic-block-sections-labels.ll b/llvm/test/CodeGen/X86/basic-block-sections-labels.ll --- a/llvm/test/CodeGen/X86/basic-block-sections-labels.ll +++ b/llvm/test/CodeGen/X86/basic-block-sections-labels.ll @@ -1,23 +1,24 @@ ; Check the basic block sections labels option -; RUN: llc < %s -mtriple=x86_64-pc-linux -function-sections -basic-block-sections=labels | FileCheck %s -check-prefix=LINUX-LABELS +; RUN: llc < %s -mtriple=x86_64 -function-sections -basic-block-sections=labels | FileCheck %s -define void @_Z3bazb(i1 zeroext) { - %2 = alloca i8, align 1 - %3 = zext i1 %0 to i8 - store i8 %3, i8* %2, align 1 - %4 = load i8, i8* %2, align 1 - %5 = trunc i8 %4 to i1 - br i1 %5, label %6, label %8 +define void @_Z3bazb(i1 zeroext) personality i32 (...)* @__gxx_personality_v0 { + br i1 %0, label %2, label %7 -6: ; preds = %1 - %7 = call i32 @_Z3barv() - br label %10 +2: + %3 = invoke i32 @_Z3barv() + to label %7 unwind label %5 + br label %9 -8: ; preds = %1 - %9 = call i32 @_Z3foov() - br label %10 +5: + landingpad { i8*, i32 } + catch i8* null + br label %9 -10: ; preds = %8, %6 +7: + %8 = call i32 @_Z3foov() + br label %9 + +9: ret void } @@ -25,9 +26,31 @@ declare i32 @_Z3foov() #1 -; LINUX-LABELS: .section -; LINUX-LABELS: _Z3bazb: -; LINUX-LABELS-NOT: .section -; LINUX-LABELS: r.BB._Z3bazb: -; LINUX-LABELS-NOT: .section -; LINUX-LABELS: rr.BB._Z3bazb: +declare i32 @__gxx_personality_v0(...) + +; CHECK-LABEL: _Z3bazb: +; CHECK-LABEL: .Lfunc_begin0: +; CHECK-LABEL: .LBB_END0_0: +; CHECK-LABEL: .LBB0_1: +; CHECK-LABEL: .LBB_END0_1: +; CHECK-LABEL: .LBB0_2: +; CHECK-LABEL: .LBB_END0_2: +; CHECK-LABEL: .LBB0_3: +; CHECK-LABEL: .LBB_END0_3: +; CHECK-LABEL: .Lfunc_end0: + +; CHECK: .section .bb_addr_map,"o",@progbits,.text +; CHECK-NEXT: .quad .Lfunc_begin0 +; CHECK-NEXT: .byte 4 +; CHECK-NEXT: .uleb128 .Lfunc_begin0-.Lfunc_begin0 +; CHECK-NEXT: .uleb128 .LBB_END0_0-.Lfunc_begin0 +; CHECK-NEXT: .byte 0 +; CHECK-NEXT: .uleb128 .LBB0_1-.Lfunc_begin0 +; CHECK-NEXT: .uleb128 .LBB_END0_1-.LBB0_1 +; CHECK-NEXT: .byte 0 +; CHECK-NEXT: .uleb128 .LBB0_2-.Lfunc_begin0 +; CHECK-NEXT: .uleb128 .LBB_END0_2-.LBB0_2 +; CHECK-NEXT: .byte 1 +; CHECK-NEXT: .uleb128 .LBB0_3-.Lfunc_begin0 +; CHECK-NEXT: .uleb128 .LBB_END0_3-.LBB0_3 +; CHECK-NEXT: .byte 5