llvm/lib/CodeGen/GlobalISel/LostDebugLocObserver.cpp

   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
  13 #include "llvm/CodeGen/GlobalISel/LostDebugLocObserver.h"
  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");
  32   SmallPtrSet<MachineInstr *, 4> FoundIn;
  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
  77 void LostDebugLocObserver::createdInstr(MachineInstr &MI) {
  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
  93 void LostDebugLocObserver::erasingInstr(MachineInstr &MI) {
  94   if (irTranslatorNeverAddsLocations(MI.getOpcode()))
  95     return;
  96
  97   PotentialMIsForDebugLocs.erase(&MI);
  98   if (MI.getDebugLoc())
  99     LostDebugLocs.insert(MI.getDebugLoc());
 100 }
 101
 102 void LostDebugLocObserver::changingInstr(MachineInstr &MI) {
 103   if (irTranslatorNeverAddsLocations(MI.getOpcode()))
 104     return;
 105
 106   PotentialMIsForDebugLocs.erase(&MI);
 107   if (MI.getDebugLoc())
 108     LostDebugLocs.insert(MI.getDebugLoc());
 109 }
 110
 111 void LostDebugLocObserver::changedInstr(MachineInstr &MI) {
 112   PotentialMIsForDebugLocs.insert(&MI);
 113 }