Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
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//===-- llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp -------*- C++ -*--===//
2
//
3
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4
// See https://llvm.org/LICENSE.txt for license information.
5
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
7
//===----------------------------------------------------------------------===//
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//
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// Common functionality for different debug information format backends.
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// LLVM currently supports DWARF and CodeView.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/DebugHandlerBase.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/CodeGen/AsmPrinter.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/CodeGen/TargetSubtargetInfo.h"
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#include "llvm/IR/DebugInfo.h"
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#include "llvm/MC/MCStreamer.h"
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using namespace llvm;
26
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#define DEBUG_TYPE "dwarfdebug"
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Optional<DbgVariableLocation>
30
DbgVariableLocation::extractFromMachineInstruction(
31
163
    const MachineInstr &Instruction) {
32
163
  DbgVariableLocation Location;
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163
  if (!Instruction.isDebugValue())
34
0
    return None;
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163
  if (!Instruction.getOperand(0).isReg())
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22
    return None;
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141
  Location.Register = Instruction.getOperand(0).getReg();
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141
  Location.FragmentInfo.reset();
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141
  // We only handle expressions generated by DIExpression::appendOffset,
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141
  // which doesn't require a full stack machine.
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  int64_t Offset = 0;
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  const DIExpression *DIExpr = Instruction.getDebugExpression();
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  auto Op = DIExpr->expr_op_begin();
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195
  while (Op != DIExpr->expr_op_end()) {
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59
    switch (Op->getOp()) {
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59
    case dwarf::DW_OP_constu: {
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1
      int Value = Op->getArg(0);
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1
      ++Op;
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1
      if (Op != DIExpr->expr_op_end()) {
50
1
        switch (Op->getOp()) {
51
1
        case dwarf::DW_OP_minus:
52
1
          Offset -= Value;
53
1
          break;
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1
        case dwarf::DW_OP_plus:
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0
          Offset += Value;
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0
          break;
57
1
        default:
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0
          continue;
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1
        }
60
1
      }
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1
    } break;
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26
    case dwarf::DW_OP_plus_uconst:
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      Offset += Op->getArg(0);
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      break;
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16
    case dwarf::DW_OP_LLVM_fragment:
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16
      Location.FragmentInfo = {Op->getArg(1), Op->getArg(0)};
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16
      break;
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11
    case dwarf::DW_OP_deref:
69
11
      Location.LoadChain.push_back(Offset);
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11
      Offset = 0;
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11
      break;
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5
    default:
73
5
      return None;
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54
    }
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54
    ++Op;
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54
  }
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141
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141
  // Do one final implicit DW_OP_deref if this was an indirect DBG_VALUE
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141
  // instruction.
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141
  // FIXME: Replace these with DIExpression.
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141
  
if (136
Instruction.isIndirectDebugValue()136
)
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32
    Location.LoadChain.push_back(Offset);
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136
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136
  return Location;
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141
}
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36.1k
DebugHandlerBase::DebugHandlerBase(AsmPrinter *A) : Asm(A), MMI(Asm->MMI) {}
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// Each LexicalScope has first instruction and last instruction to mark
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// beginning and end of a scope respectively. Create an inverse map that list
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// scopes starts (and ends) with an instruction. One instruction may start (or
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// end) multiple scopes. Ignore scopes that are not reachable.
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35.7k
void DebugHandlerBase::identifyScopeMarkers() {
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35.7k
  SmallVector<LexicalScope *, 4> WorkList;
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35.7k
  WorkList.push_back(LScopes.getCurrentFunctionScope());
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351k
  while (!WorkList.empty()) {
97
315k
    LexicalScope *S = WorkList.pop_back_val();
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315k
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315k
    const SmallVectorImpl<LexicalScope *> &Children = S->getChildren();
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315k
    if (!Children.empty())
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162k
      WorkList.append(Children.begin(), Children.end());
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315k
103
315k
    if (S->isAbstractScope())
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0
      continue;
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315k
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397k
    
for (const InsnRange &R : S->getRanges())315k
{
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397k
      assert(R.first && "InsnRange does not have first instruction!");
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397k
      assert(R.second && "InsnRange does not have second instruction!");
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397k
      requestLabelBeforeInsn(R.first);
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397k
      requestLabelAfterInsn(R.second);
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397k
    }
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315k
  }
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35.7k
}
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// Return Label preceding the instruction.
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372k
MCSymbol *DebugHandlerBase::getLabelBeforeInsn(const MachineInstr *MI) {
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372k
  MCSymbol *Label = LabelsBeforeInsn.lookup(MI);
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372k
  assert(Label && "Didn't insert label before instruction");
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372k
  return Label;
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372k
}
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// Return Label immediately following the instruction.
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364k
MCSymbol *DebugHandlerBase::getLabelAfterInsn(const MachineInstr *MI) {
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364k
  return LabelsAfterInsn.lookup(MI);
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364k
}
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// Return the function-local offset of an instruction.
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const MCExpr *
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DebugHandlerBase::getFunctionLocalOffsetAfterInsn(const MachineInstr *MI) {
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  MCContext &MC = Asm->OutContext;
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  MCSymbol *Start = Asm->getFunctionBegin();
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  const auto *StartRef = MCSymbolRefExpr::create(Start, MC);
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  MCSymbol *AfterInsn = getLabelAfterInsn(MI);
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  assert(AfterInsn && "Expected label after instruction");
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  const auto *AfterRef = MCSymbolRefExpr::create(AfterInsn, MC);
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  return MCBinaryExpr::createSub(AfterRef, StartRef, MC);
140
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}
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/// If this type is derived from a base type then return base type size.
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1.34k
uint64_t DebugHandlerBase::getBaseTypeSize(const DIType *Ty) {
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1.34k
  assert(Ty);
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1.34k
  const DIDerivedType *DDTy = dyn_cast<DIDerivedType>(Ty);
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1.34k
  if (!DDTy)
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521
    return Ty->getSizeInBits();
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826
149
826
  unsigned Tag = DDTy->getTag();
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826
151
826
  if (Tag != dwarf::DW_TAG_member && 
Tag != dwarf::DW_TAG_typedef202
&&
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826
      
Tag != dwarf::DW_TAG_const_type162
&&
Tag != dwarf::DW_TAG_volatile_type153
&&
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826
      
Tag != dwarf::DW_TAG_restrict_type151
&&
Tag != dwarf::DW_TAG_atomic_type151
)
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151
    return DDTy->getSizeInBits();
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675
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675
  DIType *BaseType = DDTy->getBaseType();
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675
158
675
  if (!BaseType)
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1
    return 0;
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  // If this is a derived type, go ahead and get the base type, unless it's a
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  // reference then it's just the size of the field. Pointer types have no need
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  // of this since they're a different type of qualification on the type.
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  if (BaseType->getTag() == dwarf::DW_TAG_reference_type ||
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674
      
BaseType->getTag() == dwarf::DW_TAG_rvalue_reference_type673
)
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1
    return Ty->getSizeInBits();
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673
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673
  return getBaseTypeSize(BaseType);
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673
}
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static bool hasDebugInfo(const MachineModuleInfo *MMI,
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996k
                         const MachineFunction *MF) {
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996k
  if (!MMI->hasDebugInfo())
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922k
    return false;
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73.8k
  auto *SP = MF->getFunction().getSubprogram();
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73.8k
  if (!SP)
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2.26k
    return false;
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71.5k
  assert(SP->getUnit());
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71.5k
  auto EK = SP->getUnit()->getEmissionKind();
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71.5k
  if (EK == DICompileUnit::NoDebug)
181
6
    return false;
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71.5k
  return true;
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71.5k
}
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185
498k
void DebugHandlerBase::beginFunction(const MachineFunction *MF) {
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498k
  PrevInstBB = nullptr;
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498k
188
498k
  if (
!Asm498k
|| !hasDebugInfo(MMI, MF)) {
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462k
    skippedNonDebugFunction();
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462k
    return;
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462k
  }
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35.7k
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35.7k
  // Grab the lexical scopes for the function, if we don't have any of those
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35.7k
  // then we're not going to be able to do anything.
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35.7k
  LScopes.initialize(*MF);
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35.7k
  if (LScopes.empty()) {
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65
    beginFunctionImpl(MF);
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    return;
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  }
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35.7k
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35.7k
  // Make sure that each lexical scope will have a begin/end label.
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35.7k
  identifyScopeMarkers();
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35.7k
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35.7k
  // Calculate history for local variables.
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35.7k
  assert(DbgValues.empty() && "DbgValues map wasn't cleaned!");
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35.7k
  assert(DbgLabels.empty() && "DbgLabels map wasn't cleaned!");
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35.7k
  calculateDbgEntityHistory(MF, Asm->MF->getSubtarget().getRegisterInfo(),
208
35.7k
                            DbgValues, DbgLabels);
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35.7k
  LLVM_DEBUG(DbgValues.dump());
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35.7k
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35.7k
  // Request labels for the full history.
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35.7k
  for (const auto &I : DbgValues) {
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772
    const auto &Entries = I.second;
214
772
    if (Entries.empty())
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0
      continue;
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772
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4.37k
    
auto IsDescribedByReg = [](const MachineInstr *MI) 772
{
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4.37k
      return MI->getOperand(0).isReg() && 
MI->getOperand(0).getReg()363
;
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4.37k
    };
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772
221
772
    // The first mention of a function argument gets the CurrentFnBegin label,
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772
    // so arguments are visible when breaking at function entry.
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772
    //
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772
    // We do not change the label for values that are described by registers,
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772
    // as that could place them above their defining instructions. We should
226
772
    // ideally not change the labels for constant debug values either, since
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772
    // doing that violates the ranges that are calculated in the history map.
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772
    // However, we currently do not emit debug values for constant arguments
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772
    // directly at the start of the function, so this code is still useful.
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772
    const DILocalVariable *DIVar =
231
772
        Entries.front().getInstr()->getDebugVariable();
232
772
    if (DIVar->isParameter() &&
233
772
        
getDISubprogram(DIVar->getScope())->describes(&MF->getFunction())421
) {
234
358
      if (!IsDescribedByReg(Entries.front().getInstr()))
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18
        LabelsBeforeInsn[Entries.front().getInstr()] = Asm->getFunctionBegin();
236
358
      if (Entries.front().getInstr()->getDebugExpression()->isFragment()) {
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22
        // Mark all non-overlapping initial fragments.
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4.02k
        for (auto I = Entries.begin(); I != Entries.end(); 
++I4.00k
) {
239
4.02k
          if (!I->isDbgValue())
240
0
            continue;
241
4.02k
          const DIExpression *Fragment = I->getInstr()->getDebugExpression();
242
4.02k
          if (std::any_of(Entries.begin(), I,
243
7.99M
                          [&](DbgValueHistoryMap::Entry Pred) {
244
7.99M
                            return Pred.isDbgValue() &&
245
7.99M
                                   Fragment->fragmentsOverlap(
246
7.99M
                                       Pred.getInstr()->getDebugExpression());
247
7.99M
                          }))
248
0
            break;
249
4.02k
          // The code that generates location lists for DWARF assumes that the
250
4.02k
          // entries' start labels are monotonically increasing, and since we
251
4.02k
          // don't change the label for fragments that are described by
252
4.02k
          // registers, we must bail out when encountering such a fragment.
253
4.02k
          if (IsDescribedByReg(I->getInstr()))
254
20
            break;
255
4.00k
          LabelsBeforeInsn[I->getInstr()] = Asm->getFunctionBegin();
256
4.00k
        }
257
22
      }
258
358
    }
259
772
260
7.00k
    for (const auto &Entry : Entries) {
261
7.00k
      if (Entry.isDbgValue())
262
5.81k
        requestLabelBeforeInsn(Entry.getInstr());
263
1.18k
      else
264
1.18k
        requestLabelAfterInsn(Entry.getInstr());
265
7.00k
    }
266
772
  }
267
35.7k
268
35.7k
  // Ensure there is a symbol before DBG_LABEL.
269
35.7k
  for (const auto &I : DbgLabels) {
270
6
    const MachineInstr *MI = I.second;
271
6
    requestLabelBeforeInsn(MI);
272
6
  }
273
35.7k
274
35.7k
  PrevInstLoc = DebugLoc();
275
35.7k
  PrevLabel = Asm->getFunctionBegin();
276
35.7k
  beginFunctionImpl(MF);
277
35.7k
}
278
279
2.60M
void DebugHandlerBase::beginInstruction(const MachineInstr *MI) {
280
2.60M
  if (!MMI->hasDebugInfo())
281
0
    return;
282
2.60M
283
2.60M
  assert(CurMI == nullptr);
284
2.60M
  CurMI = MI;
285
2.60M
286
2.60M
  // Insert labels where requested.
287
2.60M
  DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
288
2.60M
      LabelsBeforeInsn.find(MI);
289
2.60M
290
2.60M
  // No label needed.
291
2.60M
  if (I == LabelsBeforeInsn.end())
292
2.35M
    return;
293
248k
294
248k
  // Label already assigned.
295
248k
  if (I->second)
296
4.01k
    return;
297
244k
298
244k
  if (!PrevLabel) {
299
181k
    PrevLabel = MMI->getContext().createTempSymbol();
300
181k
    Asm->OutStreamer->EmitLabel(PrevLabel);
301
181k
  }
302
244k
  I->second = PrevLabel;
303
244k
}
304
305
2.60M
void DebugHandlerBase::endInstruction() {
306
2.60M
  if (!MMI->hasDebugInfo())
307
0
    return;
308
2.60M
309
2.60M
  assert(CurMI != nullptr);
310
2.60M
  // Don't create a new label after DBG_VALUE and other instructions that don't
311
2.60M
  // generate code.
312
2.60M
  if (!CurMI->isMetaInstruction()) {
313
2.40M
    PrevLabel = nullptr;
314
2.40M
    PrevInstBB = CurMI->getParent();
315
2.40M
  }
316
2.60M
317
2.60M
  DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
318
2.60M
      LabelsAfterInsn.find(CurMI);
319
2.60M
  CurMI = nullptr;
320
2.60M
321
2.60M
  // No label needed.
322
2.60M
  if (I == LabelsAfterInsn.end())
323
2.35M
    return;
324
256k
325
256k
  // Label already assigned.
326
256k
  if (I->second)
327
0
    return;
328
256k
329
256k
  // We need a label after this instruction.
330
256k
  if (!PrevLabel) {
331
256k
    PrevLabel = MMI->getContext().createTempSymbol();
332
256k
    Asm->OutStreamer->EmitLabel(PrevLabel);
333
256k
  }
334
256k
  I->second = PrevLabel;
335
256k
}
336
337
498k
void DebugHandlerBase::endFunction(const MachineFunction *MF) {
338
498k
  if (hasDebugInfo(MMI, MF))
339
35.7k
    endFunctionImpl(MF);
340
498k
  DbgValues.clear();
341
498k
  DbgLabels.clear();
342
498k
  LabelsBeforeInsn.clear();
343
498k
  LabelsAfterInsn.clear();
344
498k
}