[llvm] [AsmPrinter] Reduce AsmPrinterHandlers virt. fn calls (PR #96785)

Alexis Engelke via llvm-commits llvm-commits at lists.llvm.org
Wed Jun 26 08:39:00 PDT 2024


https://github.com/aengelke created https://github.com/llvm/llvm-project/pull/96785

Currently, an AsmPrinterHandler has several methods that allow to dynamically hook in unwind or debug info emission, e.g. at begin/end of every function or instruction. The class hierarchy and the actually overriden functions are as follows:

    (SymSz=setSymbolSize, mFE=markFunctionEnd, BBS=BasicBlockSection,
     FL=Funclet; b=beginX, e=endX)
                          SymSz   Mod Fn  mFE BBS FL  Inst
    AsmPrinterHandler     -       -   -   -   -   -   -
    ` PseudoProbeHandler  -       -   -   -   -   -   -
    ` WinCFGuard          -       e   e   -   -   -   -
    ` EHStreamer          -       -   -   -   -   -   -
      ` DwarfCFIException -       e   be  -   be  -   -
      ` ARMException      -       -   be  e   -   -   -
      ` AIXException      -       -   e   -   -   -   -
      ` WinException      -       e   be  e   -   be  -
      ` WasmException     -       e   be  -   -   -   -
    ` DebugHandlerBase    -       b   be  -   be  -   be
      ` BTFDebug          -       e   -   -   -   -   b
      ` CodeViewDebug     -       be  -   -   -   -   b
      ` DWARFDebug        yes     be  -   -   -   -   b

Doing virtual function calls per instruction is costly and useless when the called function does nothing.

This commit performs the following clean-up/improvements:

- PseudoProbeHandler is no longer an AsmPrinterHandler -- it used nothing of its functionality to hook in at the possible points. This avoids virtual function calls when a pseudo probe printer is present.

- DebugHandlerBase is no longer an AsmPrinterHandler, but a separate base class. DebugHandlerBase is the only remaining "hook" for begin/end instruction and setSymbolSize (only used by DWARFDebug). begin/end for function and basic block sections are never overriden and therefore are no longer virtual. (Originally I intended there to be only one debug handler, but BPF as the only target supports two at the same time: DWARF and BTF.)

- AsmPrinterHandler no longer has begin/end instruction and setSymbolSize hooks -- these were only used by DebugHandlerBase. This avoid iterating over handlers in every instruction.

- Remove NamedRegionTimer from instruction loop. Checking a global variable for every instruction (and doing an out-of-line function call) is too expensive for a profiling functionality.

```
    AsmPrinterHandler     Mod Fn  mFE BBS FL
    ` WinCFGuard          e   e   -   -   -
    ` EHStreamer          -   -   -   -   -
      ` DwarfCFIException e   be  -   be  -
      ` ARMException      -   be  e   -   -
      ` AIXException      -   e   -   -   -
      ` WinException      e   be  e   -   be
      ` WasmException     e   be  -   -   -

                          SymSz   Mod Fn  BBS Inst
    DebugHandlerBase      -       b   be  be  be
    ` BTFDebug            -       e           b
    ` CodeViewDebug       -       be          b
    ` DWARFDebug          yes     be          b

    PseudoProbeHandler (no shared methods)
```

This results in a performance improvement, especially in the -O0 -g0 case with unwind information (e.g., JIT baseline).

---

http://llvm-compile-time-tracker.com/compare.php?from=54cb5ca9f48fc542b920662a0eee7c0e6f35bee0&to=9ce05be2903285e1681ced36e5862ad3e155cb17&stat=instructions%3Au

>From fdc2db689530f3b01c78faeb1dd4308e3c128140 Mon Sep 17 00:00:00 2001
From: Alexis Engelke <engelke at in.tum.de>
Date: Wed, 26 Jun 2024 16:30:00 +0200
Subject: [PATCH] [CodeGen] Reduce AsmPrinterHandlers virt. fn calls

Currently, an AsmPrinterHandler has several methods that allow to
dynamically hook in unwind or debug info emission, e.g. at begin/end of
every function or instruction. The class hierarchy and the actually
overriden functions are as follows:

    (SymSz=setSymbolSize, mFE=markFunctionEnd, BBS=BasicBlockSection,
     FL=Funclet; b=beginX, e=endX)
                          SymSz   Mod Fn  mFE BBS FL  Inst
    AsmPrinterHandler     -       -   -   -   -   -   -
    ` PseudoProbeHandler  -       -   -   -   -   -   -
    ` WinCFGuard          -       e   e   -   -   -   -
    ` EHStreamer          -       -   -   -   -   -   -
      ` DwarfCFIException -       e   be  -   be  -   -
      ` ARMException      -       -   be  e   -   -   -
      ` AIXException      -       -   e   -   -   -   -
      ` WinException      -       e   be  e   -   be  -
      ` WasmException     -       e   be  -   -   -   -
    ` DebugHandlerBase    -       b   be  -   be  -   be
      ` BTFDebug          -       e   -   -   -   -   b
      ` CodeViewDebug     -       be  -   -   -   -   b
      ` DWARFDebug        yes     be  -   -   -   -   b

Doing virtual function calls per instruction is costly and useless when
the called function does nothing.

This commit performs the following clean-up/improvements:

- PseudoProbeHandler is no longer an AsmPrinterHandler -- it used
  nothing of its functionality to hook in at the possible points. This
  avoids virtual function calls when a pseudo probe printer is present.

- DebugHandlerBase is no longer an AsmPrinterHandler, but a separate
  base class. DebugHandlerBase is the only remaining "hook" for
  begin/end instruction and setSymbolSize (only used by DWARFDebug).
  begin/end for function and basic block sections are never overriden
  and therefore are no longer virtual. (Originally I intended there to
  be only one debug handler, but BPF as the only target supports two at
  the same time: DWARF and BTF.)

- AsmPrinterHandler no longer has begin/end instruction and
  setSymbolSize hooks -- these were only used by DebugHandlerBase. This
  avoid iterating over handlers in every instruction.

- Remove NamedRegionTimer from instruction loop. Checking a global
  variable for every instruction (and doing an out-of-line function
  call) is too expensive for a profiling functionality.

    AsmPrinterHandler     Mod Fn  mFE BBS FL
    ` WinCFGuard          e   e   -   -   -
    ` EHStreamer          -   -   -   -   -
      ` DwarfCFIException e   be  -   be  -
      ` ARMException      -   be  e   -   -
      ` AIXException      -   e   -   -   -
      ` WinException      e   be  e   -   be
      ` WasmException     e   be  -   -   -

                          SymSz   Mod Fn  BBS Inst
    DebugHandlerBase      -       b   be  be  be
    ` BTFDebug            -       e           b
    ` CodeViewDebug       -       be          b
    ` DWARFDebug          yes     be          b

    PseudoProbeHandler (no shared methods)

This results in a performance improvement, especially in the -O0 -g0
case with unwind information (e.g., JIT baseline).
---
 llvm/include/llvm/CodeGen/AsmPrinter.h        |  6 +-
 llvm/include/llvm/CodeGen/AsmPrinterHandler.h | 10 ---
 llvm/include/llvm/CodeGen/DebugHandlerBase.h  | 26 ++++---
 llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp    | 72 +++++++++----------
 llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h   |  2 -
 .../CodeGen/AsmPrinter/DebugHandlerBase.cpp   |  2 +
 llvm/lib/CodeGen/AsmPrinter/EHStreamer.h      |  5 --
 .../CodeGen/AsmPrinter/PseudoProbePrinter.cpp |  2 -
 .../CodeGen/AsmPrinter/PseudoProbePrinter.h   | 11 +--
 llvm/lib/CodeGen/AsmPrinter/WinCFGuard.h      |  8 ---
 llvm/lib/Target/BPF/BPFAsmPrinter.cpp         |  4 +-
 llvm/lib/Target/BPF/BTFDebug.h                |  2 -
 .../unittests/CodeGen/AsmPrinterDwarfTest.cpp |  3 -
 13 files changed, 58 insertions(+), 95 deletions(-)

diff --git a/llvm/include/llvm/CodeGen/AsmPrinter.h b/llvm/include/llvm/CodeGen/AsmPrinter.h
index 011f8c6534b6a..317798f25d58c 100644
--- a/llvm/include/llvm/CodeGen/AsmPrinter.h
+++ b/llvm/include/llvm/CodeGen/AsmPrinter.h
@@ -40,6 +40,7 @@ class Constant;
 class ConstantArray;
 class ConstantPtrAuth;
 class DataLayout;
+class DebugHandlerBase;
 class DIE;
 class DIEAbbrev;
 class DwarfDebug;
@@ -208,6 +209,9 @@ class AsmPrinter : public MachineFunctionPass {
   std::vector<HandlerInfo> Handlers;
   size_t NumUserHandlers = 0;
 
+  /// Debuginfo handler. Protected so that targets can add their own.
+  SmallVector<std::unique_ptr<DebugHandlerBase>, 1> DebugHandlers;
+
   StackMaps SM;
 
 private:
@@ -222,7 +226,7 @@ class AsmPrinter : public MachineFunctionPass {
 
   /// A handler that supports pseudo probe emission with embedded inline
   /// context.
-  PseudoProbeHandler *PP = nullptr;
+  std::unique_ptr<PseudoProbeHandler> PP;
 
   /// CFISection type the module needs i.e. either .eh_frame or .debug_frame.
   CFISection ModuleCFISection = CFISection::None;
diff --git a/llvm/include/llvm/CodeGen/AsmPrinterHandler.h b/llvm/include/llvm/CodeGen/AsmPrinterHandler.h
index 5c06645f767eb..ed73e618431de 100644
--- a/llvm/include/llvm/CodeGen/AsmPrinterHandler.h
+++ b/llvm/include/llvm/CodeGen/AsmPrinterHandler.h
@@ -34,10 +34,6 @@ class AsmPrinterHandler {
 public:
   virtual ~AsmPrinterHandler();
 
-  /// For symbols that have a size designated (e.g. common symbols),
-  /// this tracks that size.
-  virtual void setSymbolSize(const MCSymbol *Sym, uint64_t Size) = 0;
-
   virtual void beginModule(Module *M) {}
 
   /// Emit all sections that should come after the content.
@@ -72,12 +68,6 @@ class AsmPrinterHandler {
   virtual void beginFunclet(const MachineBasicBlock &MBB,
                             MCSymbol *Sym = nullptr) {}
   virtual void endFunclet() {}
-
-  /// Process beginning of an instruction.
-  virtual void beginInstruction(const MachineInstr *MI) = 0;
-
-  /// Process end of an instruction.
-  virtual void endInstruction() = 0;
 };
 
 } // End of namespace llvm
diff --git a/llvm/include/llvm/CodeGen/DebugHandlerBase.h b/llvm/include/llvm/CodeGen/DebugHandlerBase.h
index af25f2544da71..0436651a9fd48 100644
--- a/llvm/include/llvm/CodeGen/DebugHandlerBase.h
+++ b/llvm/include/llvm/CodeGen/DebugHandlerBase.h
@@ -50,10 +50,14 @@ struct DbgVariableLocation {
 
 /// Base class for debug information backends. Common functionality related to
 /// tracking which variables and scopes are alive at a given PC live here.
-class DebugHandlerBase : public AsmPrinterHandler {
+class DebugHandlerBase {
 protected:
   DebugHandlerBase(AsmPrinter *A);
 
+public:
+  virtual ~DebugHandlerBase();
+
+protected:
   /// Target of debug info emission.
   AsmPrinter *Asm = nullptr;
 
@@ -116,18 +120,22 @@ class DebugHandlerBase : public AsmPrinterHandler {
 private:
   InstructionOrdering InstOrdering;
 
-  // AsmPrinterHandler overrides.
 public:
-  void beginModule(Module *M) override;
+  /// For symbols that have a size designated (e.g. common symbols),
+  /// this tracks that size. Only used by DWARF.
+  virtual void setSymbolSize(const MCSymbol *Sym, uint64_t Size) {};
+
+  virtual void beginModule(Module *M);
+  virtual void endModule() = 0;
 
-  void beginInstruction(const MachineInstr *MI) override;
-  void endInstruction() override;
+  virtual void beginInstruction(const MachineInstr *MI);
+  virtual void endInstruction();
 
-  void beginFunction(const MachineFunction *MF) override;
-  void endFunction(const MachineFunction *MF) override;
+  void beginFunction(const MachineFunction *MF);
+  void endFunction(const MachineFunction *MF);
 
-  void beginBasicBlockSection(const MachineBasicBlock &MBB) override;
-  void endBasicBlockSection(const MachineBasicBlock &MBB) override;
+  void beginBasicBlockSection(const MachineBasicBlock &MBB);
+  void endBasicBlockSection(const MachineBasicBlock &MBB);
 
   /// Return Label preceding the instruction.
   MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 40f4dc2689cdf..4f54152c4527e 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -158,18 +158,10 @@ static cl::bits<PGOMapFeaturesEnum> PgoAnalysisMapFeatures(
 
 const char DWARFGroupName[] = "dwarf";
 const char DWARFGroupDescription[] = "DWARF Emission";
-const char DbgTimerName[] = "emit";
-const char DbgTimerDescription[] = "Debug Info Emission";
 const char EHTimerName[] = "write_exception";
 const char EHTimerDescription[] = "DWARF Exception Writer";
 const char CFGuardName[] = "Control Flow Guard";
 const char CFGuardDescription[] = "Control Flow Guard";
-const char CodeViewLineTablesGroupName[] = "linetables";
-const char CodeViewLineTablesGroupDescription[] = "CodeView Line Tables";
-const char PPTimerName[] = "emit";
-const char PPTimerDescription[] = "Pseudo Probe Emission";
-const char PPGroupName[] = "pseudo probe";
-const char PPGroupDescription[] = "Pseudo Probe Emission";
 
 STATISTIC(EmittedInsts, "Number of machine instrs printed");
 
@@ -552,28 +544,19 @@ bool AsmPrinter::doInitialization(Module &M) {
 
   if (MAI->doesSupportDebugInformation()) {
     bool EmitCodeView = M.getCodeViewFlag();
-    if (EmitCodeView && TM.getTargetTriple().isOSWindows()) {
-      Handlers.emplace_back(std::make_unique<CodeViewDebug>(this),
-                            DbgTimerName, DbgTimerDescription,
-                            CodeViewLineTablesGroupName,
-                            CodeViewLineTablesGroupDescription);
-    }
+    if (EmitCodeView && TM.getTargetTriple().isOSWindows())
+      DebugHandlers.push_back(std::make_unique<CodeViewDebug>(this));
     if (!EmitCodeView || M.getDwarfVersion()) {
       assert(MMI && "MMI could not be nullptr here!");
       if (MMI->hasDebugInfo()) {
         DD = new DwarfDebug(this);
-        Handlers.emplace_back(std::unique_ptr<DwarfDebug>(DD), DbgTimerName,
-                              DbgTimerDescription, DWARFGroupName,
-                              DWARFGroupDescription);
+        DebugHandlers.push_back(std::unique_ptr<DwarfDebug>(DD));
       }
     }
   }
 
-  if (M.getNamedMetadata(PseudoProbeDescMetadataName)) {
-    PP = new PseudoProbeHandler(this);
-    Handlers.emplace_back(std::unique_ptr<PseudoProbeHandler>(PP), PPTimerName,
-                          PPTimerDescription, PPGroupName, PPGroupDescription);
-  }
+  if (M.getNamedMetadata(PseudoProbeDescMetadataName))
+    PP = std::make_unique<PseudoProbeHandler>(this);
 
   switch (MAI->getExceptionHandlingType()) {
   case ExceptionHandling::None:
@@ -640,6 +623,8 @@ bool AsmPrinter::doInitialization(Module &M) {
                           CFGuardDescription, DWARFGroupName,
                           DWARFGroupDescription);
 
+  for (auto &DH : DebugHandlers)
+    DH->beginModule(&M);
   for (const HandlerInfo &HI : Handlers) {
     NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
                        HI.TimerGroupDescription, TimePassesIsEnabled);
@@ -791,12 +776,8 @@ void AsmPrinter::emitGlobalVariable(const GlobalVariable *GV) {
   // sections and expected to be contiguous (e.g. ObjC metadata).
   const Align Alignment = getGVAlignment(GV, DL);
 
-  for (const HandlerInfo &HI : Handlers) {
-    NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
-                       HI.TimerGroupName, HI.TimerGroupDescription,
-                       TimePassesIsEnabled);
-    HI.Handler->setSymbolSize(GVSym, Size);
-  }
+  for (auto &DH : DebugHandlers)
+    DH->setSymbolSize(GVSym, Size);
 
   // Handle common symbols
   if (GVKind.isCommon()) {
@@ -1067,6 +1048,10 @@ void AsmPrinter::emitFunctionHeader() {
   }
 
   // Emit pre-function debug and/or EH information.
+  for (auto &DH : DebugHandlers) {
+    DH->beginFunction(MF);
+    DH->beginBasicBlockSection(MF->front());
+  }
   for (const HandlerInfo &HI : Handlers) {
     NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
                        HI.TimerGroupDescription, TimePassesIsEnabled);
@@ -1770,11 +1755,8 @@ void AsmPrinter::emitFunctionBody() {
       if (MDNode *MD = MI.getPCSections())
         emitPCSectionsLabel(*MF, *MD);
 
-      for (const HandlerInfo &HI : Handlers) {
-        NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
-                           HI.TimerGroupDescription, TimePassesIsEnabled);
-        HI.Handler->beginInstruction(&MI);
-      }
+      for (auto &DH : DebugHandlers)
+        DH->beginInstruction(&MI);
 
       if (isVerbose())
         emitComments(MI, OutStreamer->getCommentOS());
@@ -1868,11 +1850,8 @@ void AsmPrinter::emitFunctionBody() {
       if (MCSymbol *S = MI.getPostInstrSymbol())
         OutStreamer->emitLabel(S);
 
-      for (const HandlerInfo &HI : Handlers) {
-        NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
-                           HI.TimerGroupDescription, TimePassesIsEnabled);
-        HI.Handler->endInstruction();
-      }
+      for (auto &DH : DebugHandlers)
+        DH->endInstruction();
     }
 
     // We must emit temporary symbol for the end of this basic block, if either
@@ -2003,6 +1982,8 @@ void AsmPrinter::emitFunctionBody() {
   // Call endBasicBlockSection on the last block now, if it wasn't already
   // called.
   if (!MF->back().isEndSection()) {
+    for (auto &DH : DebugHandlers)
+      DH->endBasicBlockSection(MF->back());
     for (const HandlerInfo &HI : Handlers) {
       NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
                          HI.TimerGroupDescription, TimePassesIsEnabled);
@@ -2022,6 +2003,8 @@ void AsmPrinter::emitFunctionBody() {
   emitJumpTableInfo();
 
   // Emit post-function debug and/or EH information.
+  for (auto &DH : DebugHandlers)
+    DH->endFunction(MF);
   for (const HandlerInfo &HI : Handlers) {
     NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
                        HI.TimerGroupDescription, TimePassesIsEnabled);
@@ -2463,6 +2446,8 @@ bool AsmPrinter::doFinalization(Module &M) {
     emitGlobalIFunc(M, IFunc);
 
   // Finalize debug and EH information.
+  for (auto &DH : DebugHandlers)
+    DH->endModule();
   for (const HandlerInfo &HI : Handlers) {
     NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
                        HI.TimerGroupDescription, TimePassesIsEnabled);
@@ -2473,6 +2458,7 @@ bool AsmPrinter::doFinalization(Module &M) {
   // keeping all the user-added handlers alive until the AsmPrinter is
   // destroyed.
   Handlers.erase(Handlers.begin() + NumUserHandlers, Handlers.end());
+  DebugHandlers.clear();
   DD = nullptr;
 
   // If the target wants to know about weak references, print them all.
@@ -4059,17 +4045,23 @@ void AsmPrinter::emitBasicBlockStart(const MachineBasicBlock &MBB) {
   // With BB sections, each basic block must handle CFI information on its own
   // if it begins a section (Entry block call is handled separately, next to
   // beginFunction).
-  if (MBB.isBeginSection() && !MBB.isEntryBlock())
+  if (MBB.isBeginSection() && !MBB.isEntryBlock()) {
+    for (auto &DH : DebugHandlers)
+      DH->beginBasicBlockSection(MBB);
     for (const HandlerInfo &HI : Handlers)
       HI.Handler->beginBasicBlockSection(MBB);
+  }
 }
 
 void AsmPrinter::emitBasicBlockEnd(const MachineBasicBlock &MBB) {
   // Check if CFI information needs to be updated for this MBB with basic block
   // sections.
-  if (MBB.isEndSection())
+  if (MBB.isEndSection()) {
+    for (auto &DH : DebugHandlers)
+      DH->endBasicBlockSection(MBB);
     for (const HandlerInfo &HI : Handlers)
       HI.Handler->endBasicBlockSection(MBB);
+  }
 }
 
 void AsmPrinter::emitVisibility(MCSymbol *Sym, unsigned Visibility,
diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h
index 55d149e049c94..7a138a0332b6d 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h
@@ -517,8 +517,6 @@ class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
 
   void beginModule(Module *M) override;
 
-  void setSymbolSize(const MCSymbol *, uint64_t) override {}
-
   /// Emit the COFF section that holds the line table information.
   void endModule() override;
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp b/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
index 24cd1b15a5736..df350b9d4814d 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
@@ -99,6 +99,8 @@ DbgVariableLocation::extractFromMachineInstruction(
 
 DebugHandlerBase::DebugHandlerBase(AsmPrinter *A) : Asm(A), MMI(Asm->MMI) {}
 
+DebugHandlerBase::~DebugHandlerBase() = default;
+
 void DebugHandlerBase::beginModule(Module *M) {
   if (M->debug_compile_units().empty())
     Asm = nullptr;
diff --git a/llvm/lib/CodeGen/AsmPrinter/EHStreamer.h b/llvm/lib/CodeGen/AsmPrinter/EHStreamer.h
index 234e62506a563..705a61fb827f3 100644
--- a/llvm/lib/CodeGen/AsmPrinter/EHStreamer.h
+++ b/llvm/lib/CodeGen/AsmPrinter/EHStreamer.h
@@ -150,11 +150,6 @@ class LLVM_LIBRARY_VISIBILITY EHStreamer : public AsmPrinterHandler {
   EHStreamer(AsmPrinter *A);
   ~EHStreamer() override;
 
-  // Unused.
-  void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {}
-  void beginInstruction(const MachineInstr *MI) override {}
-  void endInstruction() override {}
-
   /// Return `true' if this is a call to a function marked `nounwind'. Return
   /// `false' otherwise.
   static bool callToNoUnwindFunction(const MachineInstr *MI);
diff --git a/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp
index 59c3fa15885e2..5dda38383a656 100644
--- a/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp
@@ -20,8 +20,6 @@
 
 using namespace llvm;
 
-PseudoProbeHandler::~PseudoProbeHandler() = default;
-
 void PseudoProbeHandler::emitPseudoProbe(uint64_t Guid, uint64_t Index,
                                          uint64_t Type, uint64_t Attr,
                                          const DILocation *DebugLoc) {
diff --git a/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.h b/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.h
index a92a89084cadb..c9aaed4800f25 100644
--- a/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.h
+++ b/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.h
@@ -21,7 +21,7 @@ namespace llvm {
 class AsmPrinter;
 class DILocation;
 
-class PseudoProbeHandler : public AsmPrinterHandler {
+class PseudoProbeHandler {
   // Target of pseudo probe emission.
   AsmPrinter *Asm;
   // Name to GUID map, used as caching/memoization for speed.
@@ -29,18 +29,9 @@ class PseudoProbeHandler : public AsmPrinterHandler {
 
 public:
   PseudoProbeHandler(AsmPrinter *A) : Asm(A){};
-  ~PseudoProbeHandler() override;
 
   void emitPseudoProbe(uint64_t Guid, uint64_t Index, uint64_t Type,
                        uint64_t Attr, const DILocation *DebugLoc);
-
-  // Unused.
-  void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {}
-  void endModule() override {}
-  void beginFunction(const MachineFunction *MF) override {}
-  void endFunction(const MachineFunction *MF) override {}
-  void beginInstruction(const MachineInstr *MI) override {}
-  void endInstruction() override {}
 };
 
 } // namespace llvm
diff --git a/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.h b/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.h
index 0e472af52c8fa..f94acc912483d 100644
--- a/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.h
+++ b/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.h
@@ -30,8 +30,6 @@ class LLVM_LIBRARY_VISIBILITY WinCFGuard : public AsmPrinterHandler {
   WinCFGuard(AsmPrinter *A);
   ~WinCFGuard() override;
 
-  void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {}
-
   /// Emit the Control Flow Guard function ID table.
   void endModule() override;
 
@@ -44,12 +42,6 @@ class LLVM_LIBRARY_VISIBILITY WinCFGuard : public AsmPrinterHandler {
   /// Please note that some AsmPrinter implementations may not call
   /// beginFunction at all.
   void endFunction(const MachineFunction *MF) override;
-
-  /// Process beginning of an instruction.
-  void beginInstruction(const MachineInstr *MI) override {}
-
-  /// Process end of an instruction.
-  void endInstruction() override {}
 };
 
 } // namespace llvm
diff --git a/llvm/lib/Target/BPF/BPFAsmPrinter.cpp b/llvm/lib/Target/BPF/BPFAsmPrinter.cpp
index c8849bd50464c..c8a47d6d55d7c 100644
--- a/llvm/lib/Target/BPF/BPFAsmPrinter.cpp
+++ b/llvm/lib/Target/BPF/BPFAsmPrinter.cpp
@@ -61,9 +61,7 @@ bool BPFAsmPrinter::doInitialization(Module &M) {
   // Only emit BTF when debuginfo available.
   if (MAI->doesSupportDebugInformation() && !M.debug_compile_units().empty()) {
     BTF = new BTFDebug(this);
-    Handlers.push_back(HandlerInfo(std::unique_ptr<BTFDebug>(BTF), "emit",
-                                   "Debug Info Emission", "BTF",
-                                   "BTF Emission"));
+    DebugHandlers.push_back(std::unique_ptr<BTFDebug>(BTF));
   }
 
   return false;
diff --git a/llvm/lib/Target/BPF/BTFDebug.h b/llvm/lib/Target/BPF/BTFDebug.h
index 11a0c59ba6c90..3ef4a85299b65 100644
--- a/llvm/lib/Target/BPF/BTFDebug.h
+++ b/llvm/lib/Target/BPF/BTFDebug.h
@@ -420,8 +420,6 @@ class BTFDebug : public DebugHandlerBase {
     return DIToIdMap[Ty];
   }
 
-  void setSymbolSize(const MCSymbol *Symbol, uint64_t Size) override {}
-
   /// Process beginning of an instruction.
   void beginInstruction(const MachineInstr *MI) override;
 
diff --git a/llvm/unittests/CodeGen/AsmPrinterDwarfTest.cpp b/llvm/unittests/CodeGen/AsmPrinterDwarfTest.cpp
index 32319f1e97587..01b0bce80d10e 100644
--- a/llvm/unittests/CodeGen/AsmPrinterDwarfTest.cpp
+++ b/llvm/unittests/CodeGen/AsmPrinterDwarfTest.cpp
@@ -382,13 +382,10 @@ class AsmPrinterHandlerTest : public AsmPrinterFixtureBase {
   public:
     TestHandler(AsmPrinterHandlerTest &Test) : Test(Test) {}
     virtual ~TestHandler() {}
-    virtual void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {}
     virtual void beginModule(Module *M) override { Test.BeginCount++; }
     virtual void endModule() override { Test.EndCount++; }
     virtual void beginFunction(const MachineFunction *MF) override {}
     virtual void endFunction(const MachineFunction *MF) override {}
-    virtual void beginInstruction(const MachineInstr *MI) override {}
-    virtual void endInstruction() override {}
   };
 
 protected:



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