LLVM  14.0.0git
LostDebugLocObserver.cpp
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1 //===----- llvm/CodeGen/GlobalISel/LostDebugLocObserver.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
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 /// Tracks DebugLocs between checkpoints and verifies that they are transferred.
10 //
11 //===----------------------------------------------------------------------===//
12 
14 
15 using namespace llvm;
16 
17 #define LOC_DEBUG(X) DEBUG_WITH_TYPE(DebugType.str().c_str(), X)
18 
19 void LostDebugLocObserver::analyzeDebugLocations() {
20  if (LostDebugLocs.empty()) {
21  LOC_DEBUG(dbgs() << ".. No debug info was present\n");
22  return;
23  }
24  if (PotentialMIsForDebugLocs.empty()) {
25  LOC_DEBUG(
26  dbgs() << ".. No instructions to carry debug info (dead code?)\n");
27  return;
28  }
29 
30  LOC_DEBUG(dbgs() << ".. Searching " << PotentialMIsForDebugLocs.size()
31  << " instrs for " << LostDebugLocs.size() << " locations\n");
33  for (MachineInstr *MI : PotentialMIsForDebugLocs) {
34  if (!MI->getDebugLoc())
35  continue;
36  // Check this first in case there's a matching line-0 location on both input
37  // and output.
38  if (MI->getDebugLoc().getLine() == 0) {
39  LOC_DEBUG(
40  dbgs() << ".. Assuming line-0 location covers remainder (if any)\n");
41  return;
42  }
43  if (LostDebugLocs.erase(MI->getDebugLoc())) {
44  LOC_DEBUG(dbgs() << ".. .. found " << MI->getDebugLoc() << " in " << *MI);
45  FoundIn.insert(MI);
46  continue;
47  }
48  }
49  if (LostDebugLocs.empty())
50  return;
51 
52  NumLostDebugLocs += LostDebugLocs.size();
53  LOC_DEBUG({
54  dbgs() << ".. Lost locations:\n";
55  for (const DebugLoc &Loc : LostDebugLocs) {
56  dbgs() << ".. .. ";
57  Loc.print(dbgs());
58  dbgs() << "\n";
59  }
60  dbgs() << ".. MIs with matched locations:\n";
61  for (MachineInstr *MI : FoundIn)
62  if (PotentialMIsForDebugLocs.erase(MI))
63  dbgs() << ".. .. " << *MI;
64  dbgs() << ".. Remaining MIs with unmatched/no locations:\n";
65  for (const MachineInstr *MI : PotentialMIsForDebugLocs)
66  dbgs() << ".. .. " << *MI;
67  });
68 }
69 
70 void LostDebugLocObserver::checkpoint(bool CheckDebugLocs) {
71  if (CheckDebugLocs)
72  analyzeDebugLocations();
73  PotentialMIsForDebugLocs.clear();
74  LostDebugLocs.clear();
75 }
76 
78  PotentialMIsForDebugLocs.insert(&MI);
79 }
80 
81 static bool irTranslatorNeverAddsLocations(unsigned Opcode) {
82  switch (Opcode) {
83  default:
84  return false;
85  case TargetOpcode::G_CONSTANT:
86  case TargetOpcode::G_FCONSTANT:
87  case TargetOpcode::G_IMPLICIT_DEF:
88  case TargetOpcode::G_GLOBAL_VALUE:
89  return true;
90  }
91 }
92 
94  if (irTranslatorNeverAddsLocations(MI.getOpcode()))
95  return;
96 
97  PotentialMIsForDebugLocs.erase(&MI);
98  if (MI.getDebugLoc())
99  LostDebugLocs.insert(MI.getDebugLoc());
100 }
101 
103  if (irTranslatorNeverAddsLocations(MI.getOpcode()))
104  return;
105 
106  PotentialMIsForDebugLocs.erase(&MI);
107  if (MI.getDebugLoc())
108  LostDebugLocs.insert(MI.getDebugLoc());
109 }
110 
112  PotentialMIsForDebugLocs.insert(&MI);
113 }
MI
IRTranslator LLVM IR MI
Definition: IRTranslator.cpp:105
llvm
This file implements support for optimizing divisions by a constant.
Definition: AllocatorList.h:23
LOC_DEBUG
#define LOC_DEBUG(X)
Definition: LostDebugLocObserver.cpp:17
llvm::SmallPtrSet
SmallPtrSet - This class implements a set which is optimized for holding SmallSize or less elements.
Definition: SmallPtrSet.h:449
llvm::dbgs
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:163
llvm::LostDebugLocObserver::changedInstr
void changedInstr(MachineInstr &MI) override
This instruction was mutated in some way.
Definition: LostDebugLocObserver.cpp:111
LostDebugLocObserver.h
llvm::LostDebugLocObserver::checkpoint
void checkpoint(bool CheckDebugLocs=true)
Call this to indicate that it's a good point to assess whether locations have been lost.
Definition: LostDebugLocObserver.cpp:70
llvm::MachineInstr
Representation of each machine instruction.
Definition: MachineInstr.h:64
llvm::LostDebugLocObserver::changingInstr
void changingInstr(MachineInstr &MI) override
This instruction is about to be mutated in some way.
Definition: LostDebugLocObserver.cpp:102
llvm::LostDebugLocObserver::createdInstr
void createdInstr(MachineInstr &MI) override
An instruction has been created and inserted into the function.
Definition: LostDebugLocObserver.cpp:77
llvm::LostDebugLocObserver::erasingInstr
void erasingInstr(MachineInstr &MI) override
An instruction is about to be erased.
Definition: LostDebugLocObserver.cpp:93
llvm::DebugLoc
A debug info location.
Definition: DebugLoc.h:33
irTranslatorNeverAddsLocations
static bool irTranslatorNeverAddsLocations(unsigned Opcode)
Definition: LostDebugLocObserver.cpp:81
llvm::SmallPtrSetImpl::insert
std::pair< iterator, bool > insert(PtrType Ptr)
Inserts Ptr if and only if there is no element in the container equal to Ptr.
Definition: SmallPtrSet.h:364