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diff --git a/llvm/lib/CodeGen/AsmPrinter/DbgEntityHistoryCalculator.cpp b/llvm/lib/CodeGen/AsmPrinter/DbgEntityHistoryCalculator.cpp
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+++ b/llvm/lib/CodeGen/AsmPrinter/DbgEntityHistoryCalculator.cpp
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+//===- llvm/CodeGen/AsmPrinter/DbgEntityHistoryCalculator.cpp -------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/DbgEntityHistoryCalculator.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineOperand.h"
+#include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/CodeGen/TargetRegisterInfo.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
+#include "llvm/IR/DebugInfoMetadata.h"
+#include "llvm/IR/DebugLoc.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cassert>
+#include <map>
+#include <utility>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "dwarfdebug"
+
+namespace {
+using EntryIndex = DbgValueHistoryMap::EntryIndex;
+}
+
+// If @MI is a DBG_VALUE with debug value described by a
+// defined register, returns the number of this register.
+// In the other case, returns 0.
+static Register isDescribedByReg(const MachineInstr &MI) {
+ assert(MI.isDebugValue());
+ assert(MI.getNumOperands() == 4);
+ // If the location of variable is an entry value (DW_OP_LLVM_entry_value)
+ // do not consider it as a register location.
+ if (MI.getDebugExpression()->isEntryValue())
+ return 0;
+ // If location of variable is described using a register (directly or
+ // indirectly), this register is always a first operand.
+ return MI.getOperand(0).isReg() ? MI.getOperand(0).getReg() : Register();
+}
+
+bool DbgValueHistoryMap::startDbgValue(InlinedEntity Var,
+ const MachineInstr &MI,
+ EntryIndex &NewIndex) {
+ // Instruction range should start with a DBG_VALUE instruction for the
+ // variable.
+ assert(MI.isDebugValue() && "not a DBG_VALUE");
+ auto &Entries = VarEntries[Var];
+ if (!Entries.empty() && Entries.back().isDbgValue() &&
+ !Entries.back().isClosed() &&
+ Entries.back().getInstr()->isIdenticalTo(MI)) {
+ LLVM_DEBUG(dbgs() << "Coalescing identical DBG_VALUE entries:\n"
+ << "\t" << Entries.back().getInstr() << "\t" << MI
+ << "\n");
+ return false;
+ }
+ Entries.emplace_back(&MI, Entry::DbgValue);
+ NewIndex = Entries.size() - 1;
+ return true;
+}
+
+EntryIndex DbgValueHistoryMap::startClobber(InlinedEntity Var,
+ const MachineInstr &MI) {
+ auto &Entries = VarEntries[Var];
+ // If an instruction clobbers multiple registers that the variable is
+ // described by, then we may have already created a clobbering instruction.
+ if (Entries.back().isClobber() && Entries.back().getInstr() == &MI)
+ return Entries.size() - 1;
+ Entries.emplace_back(&MI, Entry::Clobber);
+ return Entries.size() - 1;
+}
+
+void DbgValueHistoryMap::Entry::endEntry(EntryIndex Index) {
+ // For now, instruction ranges are not allowed to cross basic block
+ // boundaries.
+ assert(isDbgValue() && "Setting end index for non-debug value");
+ assert(!isClosed() && "End index has already been set");
+ EndIndex = Index;
+}
+
+void DbgLabelInstrMap::addInstr(InlinedEntity Label, const MachineInstr &MI) {
+ assert(MI.isDebugLabel() && "not a DBG_LABEL");
+ LabelInstr[Label] = &MI;
+}
+
+namespace {
+
+// Maps physreg numbers to the variables they describe.
+using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
+using RegDescribedVarsMap = std::map<unsigned, SmallVector<InlinedEntity, 1>>;
+
+// Keeps track of the debug value entries that are currently live for each
+// inlined entity. As the history map entries are stored in a SmallVector, they
+// may be moved at insertion of new entries, so store indices rather than
+// pointers.
+using DbgValueEntriesMap = std::map<InlinedEntity, SmallSet<EntryIndex, 1>>;
+
+} // end anonymous namespace
+
+// Claim that @Var is not described by @RegNo anymore.
+static void dropRegDescribedVar(RegDescribedVarsMap &RegVars, unsigned RegNo,
+ InlinedEntity Var) {
+ const auto &I = RegVars.find(RegNo);
+ assert(RegNo != 0U && I != RegVars.end());
+ auto &VarSet = I->second;
+ const auto &VarPos = llvm::find(VarSet, Var);
+ assert(VarPos != VarSet.end());
+ VarSet.erase(VarPos);
+ // Don't keep empty sets in a map to keep it as small as possible.
+ if (VarSet.empty())
+ RegVars.erase(I);
+}
+
+// Claim that @Var is now described by @RegNo.
+static void addRegDescribedVar(RegDescribedVarsMap &RegVars, unsigned RegNo,
+ InlinedEntity Var) {
+ assert(RegNo != 0U);
+ auto &VarSet = RegVars[RegNo];
+ assert(!is_contained(VarSet, Var));
+ VarSet.push_back(Var);
+}
+
+/// Create a clobbering entry and end all open debug value entries
+/// for \p Var that are described by \p RegNo using that entry.
+static void clobberRegEntries(InlinedEntity Var, unsigned RegNo,
+ const MachineInstr &ClobberingInstr,
+ DbgValueEntriesMap &LiveEntries,
+ DbgValueHistoryMap &HistMap) {
+ EntryIndex ClobberIndex = HistMap.startClobber(Var, ClobberingInstr);
+
+ // Close all entries whose values are described by the register.
+ SmallVector<EntryIndex, 4> IndicesToErase;
+ for (auto Index : LiveEntries[Var]) {
+ auto &Entry = HistMap.getEntry(Var, Index);
+ assert(Entry.isDbgValue() && "Not a DBG_VALUE in LiveEntries");
+ if (isDescribedByReg(*Entry.getInstr()) == RegNo) {
+ IndicesToErase.push_back(Index);
+ Entry.endEntry(ClobberIndex);
+ }
+ }
+
+ // Drop all entries that have ended.
+ for (auto Index : IndicesToErase)
+ LiveEntries[Var].erase(Index);
+}
+
+/// Add a new debug value for \p Var. Closes all overlapping debug values.
+static void handleNewDebugValue(InlinedEntity Var, const MachineInstr &DV,
+ RegDescribedVarsMap &RegVars,
+ DbgValueEntriesMap &LiveEntries,
+ DbgValueHistoryMap &HistMap) {
+ EntryIndex NewIndex;
+ if (HistMap.startDbgValue(Var, DV, NewIndex)) {
+ SmallDenseMap<unsigned, bool, 4> TrackedRegs;
+
+ // If we have created a new debug value entry, close all preceding
+ // live entries that overlap.
+ SmallVector<EntryIndex, 4> IndicesToErase;
+ const DIExpression *DIExpr = DV.getDebugExpression();
+ for (auto Index : LiveEntries[Var]) {
+ auto &Entry = HistMap.getEntry(Var, Index);
+ assert(Entry.isDbgValue() && "Not a DBG_VALUE in LiveEntries");
+ const MachineInstr &DV = *Entry.getInstr();
+ bool Overlaps = DIExpr->fragmentsOverlap(DV.getDebugExpression());
+ if (Overlaps) {
+ IndicesToErase.push_back(Index);
+ Entry.endEntry(NewIndex);
+ }
+ if (Register Reg = isDescribedByReg(DV))
+ TrackedRegs[Reg] |= !Overlaps;
+ }
+
+ // If the new debug value is described by a register, add tracking of
+ // that register if it is not already tracked.
+ if (Register NewReg = isDescribedByReg(DV)) {
+ if (!TrackedRegs.count(NewReg))
+ addRegDescribedVar(RegVars, NewReg, Var);
+ LiveEntries[Var].insert(NewIndex);
+ TrackedRegs[NewReg] = true;
+ }
+
+ // Drop tracking of registers that are no longer used.
+ for (auto I : TrackedRegs)
+ if (!I.second)
+ dropRegDescribedVar(RegVars, I.first, Var);
+
+ // Drop all entries that have ended, and mark the new entry as live.
+ for (auto Index : IndicesToErase)
+ LiveEntries[Var].erase(Index);
+ LiveEntries[Var].insert(NewIndex);
+ }
+}
+
+// Terminate the location range for variables described by register at
+// @I by inserting @ClobberingInstr to their history.
+static void clobberRegisterUses(RegDescribedVarsMap &RegVars,
+ RegDescribedVarsMap::iterator I,
+ DbgValueHistoryMap &HistMap,
+ DbgValueEntriesMap &LiveEntries,
+ const MachineInstr &ClobberingInstr) {
+ // Iterate over all variables described by this register and add this
+ // instruction to their history, clobbering it.
+ for (const auto &Var : I->second)
+ clobberRegEntries(Var, I->first, ClobberingInstr, LiveEntries, HistMap);
+ RegVars.erase(I);
+}
+
+// Terminate the location range for variables described by register
+// @RegNo by inserting @ClobberingInstr to their history.
+static void clobberRegisterUses(RegDescribedVarsMap &RegVars, unsigned RegNo,
+ DbgValueHistoryMap &HistMap,
+ DbgValueEntriesMap &LiveEntries,
+ const MachineInstr &ClobberingInstr) {
+ const auto &I = RegVars.find(RegNo);
+ if (I == RegVars.end())
+ return;
+ clobberRegisterUses(RegVars, I, HistMap, LiveEntries, ClobberingInstr);
+}
+
+void llvm::calculateDbgEntityHistory(const MachineFunction *MF,
+ const TargetRegisterInfo *TRI,
+ DbgValueHistoryMap &DbgValues,
+ DbgLabelInstrMap &DbgLabels) {
+ const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
+ unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
+ Register FrameReg = TRI->getFrameRegister(*MF);
+ RegDescribedVarsMap RegVars;
+ DbgValueEntriesMap LiveEntries;
+ for (const auto &MBB : *MF) {
+ for (const auto &MI : MBB) {
+ if (MI.isDebugValue()) {
+ assert(MI.getNumOperands() > 1 && "Invalid DBG_VALUE instruction!");
+ // Use the base variable (without any DW_OP_piece expressions)
+ // as index into History. The full variables including the
+ // piece expressions are attached to the MI.
+ const DILocalVariable *RawVar = MI.getDebugVariable();
+ assert(RawVar->isValidLocationForIntrinsic(MI.getDebugLoc()) &&
+ "Expected inlined-at fields to agree");
+ InlinedEntity Var(RawVar, MI.getDebugLoc()->getInlinedAt());
+
+ handleNewDebugValue(Var, MI, RegVars, LiveEntries, DbgValues);
+ } else if (MI.isDebugLabel()) {
+ assert(MI.getNumOperands() == 1 && "Invalid DBG_LABEL instruction!");
+ const DILabel *RawLabel = MI.getDebugLabel();
+ assert(RawLabel->isValidLocationForIntrinsic(MI.getDebugLoc()) &&
+ "Expected inlined-at fields to agree");
+ // When collecting debug information for labels, there is no MCSymbol
+ // generated for it. So, we keep MachineInstr in DbgLabels in order
+ // to query MCSymbol afterward.
+ InlinedEntity L(RawLabel, MI.getDebugLoc()->getInlinedAt());
+ DbgLabels.addInstr(L, MI);
+ }
+
+ if (MI.isDebugInstr())
+ continue;
+
+ // Not a DBG_VALUE instruction. It may clobber registers which describe
+ // some variables.
+ for (const MachineOperand &MO : MI.operands()) {
+ if (MO.isReg() && MO.isDef() && MO.getReg()) {
+ // Ignore call instructions that claim to clobber SP. The AArch64
+ // backend does this for aggregate function arguments.
+ if (MI.isCall() && MO.getReg() == SP)
+ continue;
+ // If this is a virtual register, only clobber it since it doesn't
+ // have aliases.
+ if (Register::isVirtualRegister(MO.getReg()))
+ clobberRegisterUses(RegVars, MO.getReg(), DbgValues, LiveEntries,
+ MI);
+ // If this is a register def operand, it may end a debug value
+ // range. Ignore frame-register defs in the epilogue and prologue,
+ // we expect debuggers to understand that stack-locations are
+ // invalid outside of the function body.
+ else if (MO.getReg() != FrameReg ||
+ (!MI.getFlag(MachineInstr::FrameDestroy) &&
+ !MI.getFlag(MachineInstr::FrameSetup))) {
+ for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid();
+ ++AI)
+ clobberRegisterUses(RegVars, *AI, DbgValues, LiveEntries, MI);
+ }
+ } else if (MO.isRegMask()) {
+ // If this is a register mask operand, clobber all debug values in
+ // non-CSRs.
+ SmallVector<unsigned, 32> RegsToClobber;
+ // Don't consider SP to be clobbered by register masks.
+ for (auto It : RegVars) {
+ unsigned int Reg = It.first;
+ if (Reg != SP && Register::isPhysicalRegister(Reg) &&
+ MO.clobbersPhysReg(Reg))
+ RegsToClobber.push_back(Reg);
+ }
+
+ for (unsigned Reg : RegsToClobber) {
+ clobberRegisterUses(RegVars, Reg, DbgValues, LiveEntries, MI);
+ }
+ }
+ } // End MO loop.
+ } // End instr loop.
+
+ // Make sure locations for all variables are valid only until the end of
+ // the basic block (unless it's the last basic block, in which case let
+ // their liveness run off to the end of the function).
+ if (!MBB.empty() && &MBB != &MF->back()) {
+ // Iterate over all variables that have open debug values.
+ for (auto &Pair : LiveEntries) {
+ if (Pair.second.empty())
+ continue;
+
+ // Create a clobbering entry.
+ EntryIndex ClobIdx = DbgValues.startClobber(Pair.first, MBB.back());
+
+ // End all entries.
+ for (EntryIndex Idx : Pair.second) {
+ DbgValueHistoryMap::Entry &Ent = DbgValues.getEntry(Pair.first, Idx);
+ assert(Ent.isDbgValue() && !Ent.isClosed());
+ Ent.endEntry(ClobIdx);
+ }
+ }
+
+ LiveEntries.clear();
+ RegVars.clear();
+ }
+ }
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+LLVM_DUMP_METHOD void DbgValueHistoryMap::dump() const {
+ dbgs() << "DbgValueHistoryMap:\n";
+ for (const auto &VarRangePair : *this) {
+ const InlinedEntity &Var = VarRangePair.first;
+ const Entries &Entries = VarRangePair.second;
+
+ const DILocalVariable *LocalVar = cast<DILocalVariable>(Var.first);
+ const DILocation *Location = Var.second;
+
+ dbgs() << " - " << LocalVar->getName() << " at ";
+
+ if (Location)
+ dbgs() << Location->getFilename() << ":" << Location->getLine() << ":"
+ << Location->getColumn();
+ else
+ dbgs() << "<unknown location>";
+
+ dbgs() << " --\n";
+
+ for (const auto &E : enumerate(Entries)) {
+ const auto &Entry = E.value();
+ dbgs() << " Entry[" << E.index() << "]: ";
+ if (Entry.isDbgValue())
+ dbgs() << "Debug value\n";
+ else
+ dbgs() << "Clobber\n";
+ dbgs() << " Instr: " << *Entry.getInstr();
+ if (Entry.isDbgValue()) {
+ if (Entry.getEndIndex() == NoEntry)
+ dbgs() << " - Valid until end of function\n";
+ else
+ dbgs() << " - Closed by Entry[" << Entry.getEndIndex() << "]\n";
+ }
+ dbgs() << "\n";
+ }
+ }
+}
+#endif
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