[DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)
There are two forms for label debug information in DWARF format.
1. Labels in a non-inlined function:
DW_TAG_label
DW_AT_name
DW_AT_decl_file
DW_AT_decl_line
DW_AT_low_pc
2. Labels in an inlined function:
DW_TAG_label
DW_AT_abstract_origin
DW_AT_low_pc
We will collect label information from DBG_LABEL. Before every DBG_LABEL,
we will generate a temporary symbol to denote the location of the label.
The symbol could be used to get DW_AT_low_pc afterwards. So, we create a
mapping between 'inlined label' and DBG_LABEL MachineInstr in DebugHandlerBase.
The DBG_LABEL in the mapping is used to query the symbol before it.
The AbstractLabels in DwarfCompileUnit is used to process labels in inlined
functions.
We also keep a mapping between scope and labels in DwarfFile to help to
generate correct tree structure of DIEs.
It also generates label debug information under global isel.
Differential Revision: https://reviews.llvm.org/D45556
llvm-svn: 340039
diff --git a/llvm/lib/CodeGen/AsmPrinter/DbgEntityHistoryCalculator.cpp b/llvm/lib/CodeGen/AsmPrinter/DbgEntityHistoryCalculator.cpp
new file mode 100644
index 0000000..8fb4382
--- /dev/null
+++ b/llvm/lib/CodeGen/AsmPrinter/DbgEntityHistoryCalculator.cpp
@@ -0,0 +1,316 @@
+//===- llvm/CodeGen/AsmPrinter/DbgEntityHistoryCalculator.cpp -------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DbgEntityHistoryCalculator.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/STLExtras.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"
+
+// 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 unsigned isDescribedByReg(const MachineInstr &MI) {
+ assert(MI.isDebugValue());
+ assert(MI.getNumOperands() == 4);
+ // 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() : 0;
+}
+
+void DbgValueHistoryMap::startInstrRange(InlinedVariable Var,
+ const MachineInstr &MI) {
+ // Instruction range should start with a DBG_VALUE instruction for the
+ // variable.
+ assert(MI.isDebugValue() && "not a DBG_VALUE");
+ auto &Ranges = VarInstrRanges[Var];
+ if (!Ranges.empty() && Ranges.back().second == nullptr &&
+ Ranges.back().first->isIdenticalTo(MI)) {
+ LLVM_DEBUG(dbgs() << "Coalescing identical DBG_VALUE entries:\n"
+ << "\t" << Ranges.back().first << "\t" << MI << "\n");
+ return;
+ }
+ Ranges.push_back(std::make_pair(&MI, nullptr));
+}
+
+void DbgValueHistoryMap::endInstrRange(InlinedVariable Var,
+ const MachineInstr &MI) {
+ auto &Ranges = VarInstrRanges[Var];
+ // Verify that the current instruction range is not yet closed.
+ assert(!Ranges.empty() && Ranges.back().second == nullptr);
+ // For now, instruction ranges are not allowed to cross basic block
+ // boundaries.
+ assert(Ranges.back().first->getParent() == MI.getParent());
+ Ranges.back().second = &MI;
+}
+
+unsigned DbgValueHistoryMap::getRegisterForVar(InlinedVariable Var) const {
+ const auto &I = VarInstrRanges.find(Var);
+ if (I == VarInstrRanges.end())
+ return 0;
+ const auto &Ranges = I->second;
+ if (Ranges.empty() || Ranges.back().second != nullptr)
+ return 0;
+ return isDescribedByReg(*Ranges.back().first);
+}
+
+void DbgLabelInstrMap::addInstr(InlinedLabel Label, const MachineInstr &MI) {
+ assert(MI.isDebugLabel() && "not a DBG_LABEL");
+ LabelInstr[Label] = &MI;
+}
+
+namespace {
+
+// Maps physreg numbers to the variables they describe.
+using InlinedVariable = DbgValueHistoryMap::InlinedVariable;
+using RegDescribedVarsMap = std::map<unsigned, SmallVector<InlinedVariable, 1>>;
+using InlinedLabel = DbgLabelInstrMap::InlinedLabel;
+
+} // end anonymous namespace
+
+// Claim that @Var is not described by @RegNo anymore.
+static void dropRegDescribedVar(RegDescribedVarsMap &RegVars, unsigned RegNo,
+ InlinedVariable 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,
+ InlinedVariable Var) {
+ assert(RegNo != 0U);
+ auto &VarSet = RegVars[RegNo];
+ assert(!is_contained(VarSet, Var));
+ VarSet.push_back(Var);
+}
+
+// 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,
+ 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)
+ HistMap.endInstrRange(Var, ClobberingInstr);
+ 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,
+ const MachineInstr &ClobberingInstr) {
+ const auto &I = RegVars.find(RegNo);
+ if (I == RegVars.end())
+ return;
+ clobberRegisterUses(RegVars, I, HistMap, ClobberingInstr);
+}
+
+// Returns the first instruction in @MBB which corresponds to
+// the function epilogue, or nullptr if @MBB doesn't contain an epilogue.
+static const MachineInstr *getFirstEpilogueInst(const MachineBasicBlock &MBB) {
+ auto LastMI = MBB.getLastNonDebugInstr();
+ if (LastMI == MBB.end() || !LastMI->isReturn())
+ return nullptr;
+ // Assume that epilogue starts with instruction having the same debug location
+ // as the return instruction.
+ DebugLoc LastLoc = LastMI->getDebugLoc();
+ auto Res = LastMI;
+ for (MachineBasicBlock::const_reverse_iterator I = LastMI.getReverse(),
+ E = MBB.rend();
+ I != E; ++I) {
+ if (I->getDebugLoc() != LastLoc)
+ return &*Res;
+ Res = &*I;
+ }
+ // If all instructions have the same debug location, assume whole MBB is
+ // an epilogue.
+ return &*MBB.begin();
+}
+
+// Collect registers that are modified in the function body (their
+// contents is changed outside of the prologue and epilogue).
+static void collectChangingRegs(const MachineFunction *MF,
+ const TargetRegisterInfo *TRI,
+ BitVector &Regs) {
+ for (const auto &MBB : *MF) {
+ auto FirstEpilogueInst = getFirstEpilogueInst(MBB);
+
+ for (const auto &MI : MBB) {
+ // Avoid looking at prologue or epilogue instructions.
+ if (&MI == FirstEpilogueInst)
+ break;
+ if (MI.getFlag(MachineInstr::FrameSetup))
+ continue;
+
+ // Look for register defs and register masks. Register masks are
+ // typically on calls and they clobber everything not in the mask.
+ for (const MachineOperand &MO : MI.operands()) {
+ // Skip virtual registers since they are handled by the parent.
+ if (MO.isReg() && MO.isDef() && MO.getReg() &&
+ !TRI->isVirtualRegister(MO.getReg())) {
+ for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid();
+ ++AI)
+ Regs.set(*AI);
+ } else if (MO.isRegMask()) {
+ Regs.setBitsNotInMask(MO.getRegMask());
+ }
+ }
+ }
+ }
+}
+
+void llvm::calculateDbgEntityHistory(const MachineFunction *MF,
+ const TargetRegisterInfo *TRI,
+ DbgValueHistoryMap &DbgValues,
+ DbgLabelInstrMap &DbgLabels) {
+ BitVector ChangingRegs(TRI->getNumRegs());
+ collectChangingRegs(MF, TRI, ChangingRegs);
+
+ const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
+ unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
+ RegDescribedVarsMap RegVars;
+ for (const auto &MBB : *MF) {
+ for (const auto &MI : MBB) {
+ if (!MI.isDebugInstr()) {
+ // 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 (TRI->isVirtualRegister(MO.getReg()))
+ clobberRegisterUses(RegVars, MO.getReg(), DbgValues, MI);
+ // If this is a register def operand, it may end a debug value
+ // range.
+ else {
+ for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid();
+ ++AI)
+ if (ChangingRegs.test(*AI))
+ clobberRegisterUses(RegVars, *AI, DbgValues, MI);
+ }
+ } else if (MO.isRegMask()) {
+ // If this is a register mask operand, clobber all debug values in
+ // non-CSRs.
+ for (unsigned I : ChangingRegs.set_bits()) {
+ // Don't consider SP to be clobbered by register masks.
+ if (unsigned(I) != SP && TRI->isPhysicalRegister(I) &&
+ MO.clobbersPhysReg(I)) {
+ clobberRegisterUses(RegVars, I, DbgValues, MI);
+ }
+ }
+ }
+ }
+ continue;
+ }
+
+ 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");
+ InlinedVariable Var(RawVar, MI.getDebugLoc()->getInlinedAt());
+
+ if (unsigned PrevReg = DbgValues.getRegisterForVar(Var))
+ dropRegDescribedVar(RegVars, PrevReg, Var);
+
+ DbgValues.startInstrRange(Var, MI);
+
+ if (unsigned NewReg = isDescribedByReg(MI))
+ addRegDescribedVar(RegVars, NewReg, Var);
+ } 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.
+ InlinedLabel L(RawLabel, MI.getDebugLoc()->getInlinedAt());
+ DbgLabels.addInstr(L, MI);
+ }
+ }
+
+ // Make sure locations for register-described 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()) {
+ for (auto I = RegVars.begin(), E = RegVars.end(); I != E;) {
+ auto CurElem = I++; // CurElem can be erased below.
+ if (TRI->isVirtualRegister(CurElem->first) ||
+ ChangingRegs.test(CurElem->first))
+ clobberRegisterUses(RegVars, CurElem, DbgValues, MBB.back());
+ }
+ }
+ }
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+LLVM_DUMP_METHOD void DbgValueHistoryMap::dump() const {
+ dbgs() << "DbgValueHistoryMap:\n";
+ for (const auto &VarRangePair : *this) {
+ const InlinedVariable &Var = VarRangePair.first;
+ const InstrRanges &Ranges = VarRangePair.second;
+
+ const DILocalVariable *LocalVar = 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 InstrRange &Range : Ranges) {
+ dbgs() << " Begin: " << *Range.first;
+ if (Range.second)
+ dbgs() << " End : " << *Range.second;
+ dbgs() << "\n";
+ }
+ }
+}
+#endif