rahmanl updated this revision to Diff 289498.
rahmanl marked 5 inline comments as done.
rahmanl added a comment.
- Address @MaskRay's comments.
- Rebase with upstream.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D85408/new/
https://reviews.llvm.org/D85408
Files:
clang/docs/UsersManual.rst
clang/test/CodeGen/basic-block-sections.c
llvm/include/llvm/CodeGen/AsmPrinter.h
llvm/include/llvm/CodeGen/MachineFunction.h
llvm/include/llvm/MC/MCObjectFileInfo.h
llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
llvm/lib/CodeGen/BasicBlockSections.cpp
llvm/lib/CodeGen/MIRParser/MIRParser.cpp
llvm/lib/CodeGen/MachineBasicBlock.cpp
llvm/lib/CodeGen/MachineFunction.cpp
llvm/lib/MC/MCObjectFileInfo.cpp
llvm/test/CodeGen/X86/basic-block-sections-labels-functions-sections.ll
llvm/test/CodeGen/X86/basic-block-sections-labels.ll
Index: llvm/test/CodeGen/X86/basic-block-sections-labels.ll
===================================================================
--- llvm/test/CodeGen/X86/basic-block-sections-labels.ll
+++ 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-unknown-linux-gnu -function-sections -basic-block-sections=labels | FileCheck %s -check-prefix=LINUX-LABELS
-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(...)
+
+; LINUX-LABELS-LABEL: _Z3bazb:
+; LINUX-LABELS: .Lfunc_begin0:
+; LINUX-LABELS: .LBB_END0_[[L1:[0-9]+]]:
+; LINUX-LABELS: .LBB0_[[L2:[0-9]+]]:
+; LINUX-LABELS: .LBB_END0_[[L2]]:
+; LINUX-LABELS: .LBB0_[[L3:[0-9]+]]:
+; LINUX-LABELS: .LBB_END0_[[L3]]:
+; LINUX-LABELS: .LBB0_[[L4:[0-9]+]]:
+; LINUX-LABELS: .LBB_END0_[[L4]]:
+; LINUX-LABELS: .Lfunc_end0:
+
+; LINUX-LABELS: .section .bb_addr_map,"o",@progbits,.text
+; LINUX-LABELS-NEXT: .quad .Lfunc_begin0
+; LINUX-LABELS-NEXT: .byte 4
+; LINUX-LABELS-NEXT: .uleb128 .Lfunc_begin0-.Lfunc_begin0
+; LINUX-LABELS-NEXT: .uleb128 .LBB_END0_[[L1]]-.Lfunc_begin0
+; LINUX-LABELS-NEXT: .byte 0
+; LINUX-LABELS-NEXT: .uleb128 .LBB0_[[L2]]-.Lfunc_begin0
+; LINUX-LABELS-NEXT: .uleb128 .LBB_END0_[[L2]]-.LBB0_[[L2]]
+; LINUX-LABELS-NEXT: .byte 0
+; LINUX-LABELS-NEXT: .uleb128 .LBB0_[[L3]]-.Lfunc_begin0
+; LINUX-LABELS-NEXT: .uleb128 .LBB_END0_[[L3]]-.LBB0_[[L3]]
+; LINUX-LABELS-NEXT: .byte 1
+; LINUX-LABELS-NEXT: .uleb128 .LBB0_[[L4]]-.Lfunc_begin0
+; LINUX-LABELS-NEXT: .uleb128 .LBB_END0_[[L4]]-.LBB0_[[L4]]
+; LINUX-LABELS-NEXT: .byte 5
Index: llvm/test/CodeGen/X86/basic-block-sections-labels-functions-sections.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/X86/basic-block-sections-labels-functions-sections.ll
@@ -0,0 +1,35 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -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]]
Index: llvm/lib/MC/MCObjectFileInfo.cpp
===================================================================
--- llvm/lib/MC/MCObjectFileInfo.cpp
+++ llvm/lib/MC/MCObjectFileInfo.cpp
@@ -953,3 +953,21 @@
GroupName, MCSection::NonUniqueID,
cast<MCSymbolELF>(TextSec.getBeginSymbol()));
}
+
+MCSection *
+MCObjectFileInfo::getBBAddrMapSection(const MCSection &TextSec) const {
+ if (Env != IsELF)
+ return nullptr;
+
+ const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(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<MCSymbolELF>(TextSec.getBeginSymbol()));
+}
Index: llvm/lib/CodeGen/MachineFunction.cpp
===================================================================
--- llvm/lib/CodeGen/MachineFunction.cpp
+++ 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.
Index: llvm/lib/CodeGen/MachineBasicBlock.cpp
===================================================================
--- llvm/lib/CodeGen/MachineBasicBlock.cpp
+++ 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()));
Index: llvm/lib/CodeGen/MIRParser/MIRParser.cpp
===================================================================
--- llvm/lib/CodeGen/MIRParser/MIRParser.cpp
+++ 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;
Index: llvm/lib/CodeGen/BasicBlockSections.cpp
===================================================================
--- llvm/lib/CodeGen/BasicBlockSections.cpp
+++ 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
Index: llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1023,6 +1023,51 @@
MCConstantExpr::create(FrameOffset, OutContext));
}
+/// Returns the BB metadata to be emitted in the bb_addr_map section for a given
+/// basic block. The metadata can be used to capture more precise profile
+/// information. For instance, the return block bit helps to distinguish
+/// recursive return edges vs. indirect branches.
+/// The format of the metadata is described as follows:
+/// * 1st bit (LSB): set if it is a return block (return or tail call).
+/// * 2nd bit: set if it is a block ending with a tail call.
+/// * 3rd bit: set if it is an exception handling (EH) 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) {
+ assert(MF.hasBBLabels() && ".bb_addr_map section needs BB labels enabled.");
+
+ MCSection *BBAddrMapSection =
+ getObjFileLowering().getBBAddrMapSection(*MF.getSection());
+ if (!BBAddrMapSection)
+ return;
+
+ 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 auto &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 +1219,26 @@
}
// 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 +1330,11 @@
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 +1844,7 @@
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;
Index: llvm/include/llvm/MC/MCObjectFileInfo.h
===================================================================
--- llvm/include/llvm/MC/MCObjectFileInfo.h
+++ 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 {
Index: llvm/include/llvm/CodeGen/MachineFunction.h
===================================================================
--- llvm/include/llvm/CodeGen/MachineFunction.h
+++ 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();
Index: llvm/include/llvm/CodeGen/AsmPrinter.h
===================================================================
--- llvm/include/llvm/CodeGen/AsmPrinter.h
+++ 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 };
Index: clang/test/CodeGen/basic-block-sections.c
===================================================================
--- clang/test/CodeGen/basic-block-sections.c
+++ clang/test/CodeGen/basic-block-sections.c
@@ -1,12 +1,12 @@
// 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=labels -o - < %s | FileCheck %s --check-prefix=BB_LABELS
+// 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)
@@ -28,9 +28,66 @@
//
// BB_LABELS-NOT: section
// BB_LABELS: world:
-// BB_LABELS: a.BB.world:
-// BB_LABELS: aa.BB.world:
-// BB_LABELS: a.BB.another:
+// BB_LABELS: .Lfunc_begin0:
+// BB_LABELS: .LBB_END0_0:
+// BB_LABELS: .LBB0_1:
+// BB_LABELS: .LBB_END0_1:
+// BB_LABELS: .LBB0_3:
+// BB_LABELS: .LBB_END0_3:
+// BB_LABELS: .LBB0_4:
+// BB_LABELS: .LBB_END0_4:
+// BB_LABELS: .LBB0_5:
+// BB_LABELS: .LBB_END0_5:
+// BB_LABELS: .Lfunc_end0:
+//
+// BB_LABELS: .section .bb_addr_map,"o",@progbits,.text
+// BB_LABELS-NEXT: .quad .Lfunc_begin0
+// BB_LABELS-NEXT: .byte 6
+// BB_LABELS-NEXT: .uleb128 .Lfunc_begin0-.Lfunc_begin0
+// BB_LABELS-NEXT: .uleb128 .LBB_END0_0-.Lfunc_begin0
+// BB_LABELS-NEXT: .byte 0
+// BB_LABELS-NEXT: .uleb128 .LBB0_1-.Lfunc_begin0
+// BB_LABELS-NEXT: .uleb128 .LBB_END0_1-.LBB0_1
+// BB_LABELS-NEXT: .byte 0
+// BB_LABELS-NEXT: .uleb128 .LBB0_2-.Lfunc_begin0
+// BB_LABELS-NEXT: .uleb128 .LBB_END0_2-.LBB0_2
+// BB_LABELS-NEXT: .byte 0
+// BB_LABELS-NEXT: .uleb128 .LBB0_3-.Lfunc_begin0
+// BB_LABELS-NEXT: .uleb128 .LBB_END0_3-.LBB0_3
+// BB_LABELS-NEXT: .byte 0
+// BB_LABELS-NEXT: .uleb128 .LBB0_4-.Lfunc_begin0
+// BB_LABELS-NEXT: .uleb128 .LBB_END0_4-.LBB0_4
+// BB_LABELS-NEXT: .byte 0
+// BB_LABELS-NEXT: .uleb128 .LBB0_5-.Lfunc_begin0
+// BB_LABELS-NEXT: .uleb128 .LBB_END0_5-.LBB0_5
+// BB_LABELS-NEXT: .byte 1
+//
+// BB_LABELS: another:
+// BB_LABELS: .Lfunc_begin1:
+// BB_LABELS: .LBB_END1_0:
+// BB_LABELS: .LBB1_1:
+// BB_LABELS: .LBB_END1_1:
+// BB_LABELS: .LBB1_2:
+// BB_LABELS: .LBB_END1_2:
+// BB_LABELS: .LBB1_3:
+// BB_LABELS: .LBB_END1_3:
+// BB_LABELS: .Lfunc_end1:
+//
+// BB_LABELS: .section .bb_addr_map,"o",@progbits,.text
+// BB_LABELS-NEXT: .quad .Lfunc_begin1
+// BB_LABELS-NEXT: .byte 4
+// BB_LABELS-NEXT: .uleb128 .Lfunc_begin1-.Lfunc_begin1
+// BB_LABELS-NEXT: .uleb128 .LBB_END1_0-.Lfunc_begin1
+// BB_LABELS-NEXT: .byte 0
+// BB_LABELS-NEXT: .uleb128 .LBB1_1-.Lfunc_begin1
+// BB_LABELS-NEXT: .uleb128 .LBB_END1_1-.LBB1_1
+// BB_LABELS-NEXT: .byte 0
+// BB_LABELS-NEXT: .uleb128 .LBB1_2-.Lfunc_begin1
+// BB_LABELS-NEXT: .uleb128 .LBB_END1_2-.LBB1_2
+// BB_LABELS-NEXT: .byte 0
+// BB_LABELS-NEXT: .uleb128 .LBB1_3-.Lfunc_begin1
+// BB_LABELS-NEXT: .uleb128 .LBB_END1_3-.LBB1_3
+// BB_LABELS-NEXT: .byte 1
//
// BB_WORLD: .section .text.world,"ax",@progbits{{$}}
// BB_WORLD: world:
Index: clang/docs/UsersManual.rst
===================================================================
--- clang/docs/UsersManual.rst
+++ clang/docs/UsersManual.rst
@@ -1700,9 +1700,12 @@
**-fbasic-block-sections=[labels, all, list=<arg>, 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=<arg>``, 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=<arg>`` option, a file containing the subset of basic blocks
that need to placed in unique sections can be specified. The format of the
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