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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215138 91177308-0d34-0410-b5e6-96231b3b80d8
1022 lines
35 KiB
C++
1022 lines
35 KiB
C++
//===- LiveDebugVariables.cpp - Tracking debug info variables -------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the LiveDebugVariables analysis.
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//
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// Remove all DBG_VALUE instructions referencing virtual registers and replace
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// them with a data structure tracking where live user variables are kept - in a
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// virtual register or in a stack slot.
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//
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// Allow the data structure to be updated during register allocation when values
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// are moved between registers and stack slots. Finally emit new DBG_VALUE
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// instructions after register allocation is complete.
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//
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//===----------------------------------------------------------------------===//
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#include "LiveDebugVariables.h"
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#include "llvm/ADT/IntervalMap.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/CodeGen/LexicalScopes.h"
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#include "llvm/CodeGen/LiveIntervalAnalysis.h"
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#include "llvm/CodeGen/MachineDominators.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/CodeGen/VirtRegMap.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DebugInfo.h"
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#include "llvm/IR/Metadata.h"
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#include "llvm/IR/Value.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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#include "llvm/Target/TargetSubtargetInfo.h"
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#include <memory>
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using namespace llvm;
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#define DEBUG_TYPE "livedebug"
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static cl::opt<bool>
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EnableLDV("live-debug-variables", cl::init(true),
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cl::desc("Enable the live debug variables pass"), cl::Hidden);
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STATISTIC(NumInsertedDebugValues, "Number of DBG_VALUEs inserted");
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char LiveDebugVariables::ID = 0;
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INITIALIZE_PASS_BEGIN(LiveDebugVariables, "livedebugvars",
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"Debug Variable Analysis", false, false)
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INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
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INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
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INITIALIZE_PASS_END(LiveDebugVariables, "livedebugvars",
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"Debug Variable Analysis", false, false)
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void LiveDebugVariables::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired<MachineDominatorTree>();
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AU.addRequiredTransitive<LiveIntervals>();
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AU.setPreservesAll();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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LiveDebugVariables::LiveDebugVariables() : MachineFunctionPass(ID), pImpl(nullptr) {
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initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
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}
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/// LocMap - Map of where a user value is live, and its location.
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typedef IntervalMap<SlotIndex, unsigned, 4> LocMap;
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namespace {
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/// UserValueScopes - Keeps track of lexical scopes associated with a
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/// user value's source location.
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class UserValueScopes {
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DebugLoc DL;
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LexicalScopes &LS;
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SmallPtrSet<const MachineBasicBlock *, 4> LBlocks;
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public:
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UserValueScopes(DebugLoc D, LexicalScopes &L) : DL(D), LS(L) {}
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/// dominates - Return true if current scope dominates at least one machine
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/// instruction in a given machine basic block.
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bool dominates(MachineBasicBlock *MBB) {
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if (LBlocks.empty())
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LS.getMachineBasicBlocks(DL, LBlocks);
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if (LBlocks.count(MBB) != 0 || LS.dominates(DL, MBB))
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return true;
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return false;
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}
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};
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} // end anonymous namespace
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/// UserValue - A user value is a part of a debug info user variable.
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///
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/// A DBG_VALUE instruction notes that (a sub-register of) a virtual register
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/// holds part of a user variable. The part is identified by a byte offset.
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///
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/// UserValues are grouped into equivalence classes for easier searching. Two
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/// user values are related if they refer to the same variable, or if they are
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/// held by the same virtual register. The equivalence class is the transitive
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/// closure of that relation.
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namespace {
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class LDVImpl;
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class UserValue {
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const MDNode *variable; ///< The debug info variable we are part of.
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unsigned offset; ///< Byte offset into variable.
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bool IsIndirect; ///< true if this is a register-indirect+offset value.
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DebugLoc dl; ///< The debug location for the variable. This is
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///< used by dwarf writer to find lexical scope.
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UserValue *leader; ///< Equivalence class leader.
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UserValue *next; ///< Next value in equivalence class, or null.
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/// Numbered locations referenced by locmap.
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SmallVector<MachineOperand, 4> locations;
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/// Map of slot indices where this value is live.
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LocMap locInts;
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/// coalesceLocation - After LocNo was changed, check if it has become
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/// identical to another location, and coalesce them. This may cause LocNo or
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/// a later location to be erased, but no earlier location will be erased.
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void coalesceLocation(unsigned LocNo);
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/// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo.
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void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo,
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LiveIntervals &LIS, const TargetInstrInfo &TII);
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/// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs
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/// is live. Returns true if any changes were made.
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bool splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
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LiveIntervals &LIS);
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public:
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/// UserValue - Create a new UserValue.
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UserValue(const MDNode *var, unsigned o, bool i, DebugLoc L,
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LocMap::Allocator &alloc)
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: variable(var), offset(o), IsIndirect(i), dl(L), leader(this),
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next(nullptr), locInts(alloc)
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{}
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/// getLeader - Get the leader of this value's equivalence class.
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UserValue *getLeader() {
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UserValue *l = leader;
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while (l != l->leader)
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l = l->leader;
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return leader = l;
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}
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/// getNext - Return the next UserValue in the equivalence class.
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UserValue *getNext() const { return next; }
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/// match - Does this UserValue match the parameters?
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bool match(const MDNode *Var, unsigned Offset, bool indirect) const {
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return Var == variable && Offset == offset && indirect == IsIndirect;
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}
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/// merge - Merge equivalence classes.
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static UserValue *merge(UserValue *L1, UserValue *L2) {
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L2 = L2->getLeader();
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if (!L1)
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return L2;
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L1 = L1->getLeader();
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if (L1 == L2)
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return L1;
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// Splice L2 before L1's members.
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UserValue *End = L2;
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while (End->next)
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End->leader = L1, End = End->next;
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End->leader = L1;
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End->next = L1->next;
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L1->next = L2;
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return L1;
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}
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/// getLocationNo - Return the location number that matches Loc.
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unsigned getLocationNo(const MachineOperand &LocMO) {
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if (LocMO.isReg()) {
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if (LocMO.getReg() == 0)
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return ~0u;
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// For register locations we dont care about use/def and other flags.
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for (unsigned i = 0, e = locations.size(); i != e; ++i)
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if (locations[i].isReg() &&
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locations[i].getReg() == LocMO.getReg() &&
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locations[i].getSubReg() == LocMO.getSubReg())
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return i;
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} else
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for (unsigned i = 0, e = locations.size(); i != e; ++i)
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if (LocMO.isIdenticalTo(locations[i]))
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return i;
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locations.push_back(LocMO);
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// We are storing a MachineOperand outside a MachineInstr.
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locations.back().clearParent();
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// Don't store def operands.
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if (locations.back().isReg())
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locations.back().setIsUse();
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return locations.size() - 1;
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}
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/// mapVirtRegs - Ensure that all virtual register locations are mapped.
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void mapVirtRegs(LDVImpl *LDV);
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/// addDef - Add a definition point to this value.
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void addDef(SlotIndex Idx, const MachineOperand &LocMO) {
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// Add a singular (Idx,Idx) -> Loc mapping.
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LocMap::iterator I = locInts.find(Idx);
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if (!I.valid() || I.start() != Idx)
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I.insert(Idx, Idx.getNextSlot(), getLocationNo(LocMO));
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else
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// A later DBG_VALUE at the same SlotIndex overrides the old location.
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I.setValue(getLocationNo(LocMO));
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}
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/// extendDef - Extend the current definition as far as possible down the
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/// dominator tree. Stop when meeting an existing def or when leaving the live
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/// range of VNI.
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/// End points where VNI is no longer live are added to Kills.
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/// @param Idx Starting point for the definition.
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/// @param LocNo Location number to propagate.
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/// @param LR Restrict liveness to where LR has the value VNI. May be null.
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/// @param VNI When LR is not null, this is the value to restrict to.
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/// @param Kills Append end points of VNI's live range to Kills.
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/// @param LIS Live intervals analysis.
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/// @param MDT Dominator tree.
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void extendDef(SlotIndex Idx, unsigned LocNo,
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LiveRange *LR, const VNInfo *VNI,
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SmallVectorImpl<SlotIndex> *Kills,
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LiveIntervals &LIS, MachineDominatorTree &MDT,
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UserValueScopes &UVS);
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/// addDefsFromCopies - The value in LI/LocNo may be copies to other
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/// registers. Determine if any of the copies are available at the kill
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/// points, and add defs if possible.
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/// @param LI Scan for copies of the value in LI->reg.
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/// @param LocNo Location number of LI->reg.
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/// @param Kills Points where the range of LocNo could be extended.
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/// @param NewDefs Append (Idx, LocNo) of inserted defs here.
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void addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
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const SmallVectorImpl<SlotIndex> &Kills,
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SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
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MachineRegisterInfo &MRI,
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LiveIntervals &LIS);
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/// computeIntervals - Compute the live intervals of all locations after
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/// collecting all their def points.
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void computeIntervals(MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
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LiveIntervals &LIS, MachineDominatorTree &MDT,
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UserValueScopes &UVS);
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/// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
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/// live. Returns true if any changes were made.
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bool splitRegister(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
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LiveIntervals &LIS);
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/// rewriteLocations - Rewrite virtual register locations according to the
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/// provided virtual register map.
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void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI);
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/// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
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void emitDebugValues(VirtRegMap *VRM,
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LiveIntervals &LIS, const TargetInstrInfo &TRI);
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/// findDebugLoc - Return DebugLoc used for this DBG_VALUE instruction. A
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/// variable may have more than one corresponding DBG_VALUE instructions.
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/// Only first one needs DebugLoc to identify variable's lexical scope
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/// in source file.
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DebugLoc findDebugLoc();
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/// getDebugLoc - Return DebugLoc of this UserValue.
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DebugLoc getDebugLoc() { return dl;}
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void print(raw_ostream&, const TargetMachine*);
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};
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} // namespace
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/// LDVImpl - Implementation of the LiveDebugVariables pass.
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namespace {
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class LDVImpl {
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LiveDebugVariables &pass;
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LocMap::Allocator allocator;
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MachineFunction *MF;
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LiveIntervals *LIS;
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LexicalScopes LS;
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MachineDominatorTree *MDT;
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const TargetRegisterInfo *TRI;
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/// Whether emitDebugValues is called.
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bool EmitDone;
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/// Whether the machine function is modified during the pass.
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bool ModifiedMF;
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/// userValues - All allocated UserValue instances.
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SmallVector<std::unique_ptr<UserValue>, 8> userValues;
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/// Map virtual register to eq class leader.
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typedef DenseMap<unsigned, UserValue*> VRMap;
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VRMap virtRegToEqClass;
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/// Map user variable to eq class leader.
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typedef DenseMap<const MDNode *, UserValue*> UVMap;
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UVMap userVarMap;
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/// getUserValue - Find or create a UserValue.
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UserValue *getUserValue(const MDNode *Var, unsigned Offset,
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bool IsIndirect, DebugLoc DL);
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/// lookupVirtReg - Find the EC leader for VirtReg or null.
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UserValue *lookupVirtReg(unsigned VirtReg);
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/// handleDebugValue - Add DBG_VALUE instruction to our maps.
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/// @param MI DBG_VALUE instruction
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/// @param Idx Last valid SLotIndex before instruction.
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/// @return True if the DBG_VALUE instruction should be deleted.
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bool handleDebugValue(MachineInstr *MI, SlotIndex Idx);
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/// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding
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/// a UserValue def for each instruction.
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/// @param mf MachineFunction to be scanned.
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/// @return True if any debug values were found.
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bool collectDebugValues(MachineFunction &mf);
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/// computeIntervals - Compute the live intervals of all user values after
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/// collecting all their def points.
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void computeIntervals();
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public:
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LDVImpl(LiveDebugVariables *ps)
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: pass(*ps), MF(nullptr), EmitDone(false), ModifiedMF(false) {}
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bool runOnMachineFunction(MachineFunction &mf);
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/// clear - Release all memory.
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void clear() {
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MF = nullptr;
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userValues.clear();
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virtRegToEqClass.clear();
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userVarMap.clear();
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// Make sure we call emitDebugValues if the machine function was modified.
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assert((!ModifiedMF || EmitDone) &&
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"Dbg values are not emitted in LDV");
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EmitDone = false;
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ModifiedMF = false;
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}
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/// mapVirtReg - Map virtual register to an equivalence class.
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void mapVirtReg(unsigned VirtReg, UserValue *EC);
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/// splitRegister - Replace all references to OldReg with NewRegs.
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void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs);
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/// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
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void emitDebugValues(VirtRegMap *VRM);
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void print(raw_ostream&);
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};
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} // namespace
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void UserValue::print(raw_ostream &OS, const TargetMachine *TM) {
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DIVariable DV(variable);
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OS << "!\"";
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DV.printExtendedName(OS);
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OS << "\"\t";
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if (offset)
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OS << '+' << offset;
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for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
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OS << " [" << I.start() << ';' << I.stop() << "):";
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if (I.value() == ~0u)
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OS << "undef";
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else
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OS << I.value();
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}
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for (unsigned i = 0, e = locations.size(); i != e; ++i) {
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OS << " Loc" << i << '=';
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locations[i].print(OS, TM);
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}
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OS << '\n';
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}
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void LDVImpl::print(raw_ostream &OS) {
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OS << "********** DEBUG VARIABLES **********\n";
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for (unsigned i = 0, e = userValues.size(); i != e; ++i)
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userValues[i]->print(OS, &MF->getTarget());
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}
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void UserValue::coalesceLocation(unsigned LocNo) {
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unsigned KeepLoc = 0;
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for (unsigned e = locations.size(); KeepLoc != e; ++KeepLoc) {
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if (KeepLoc == LocNo)
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continue;
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if (locations[KeepLoc].isIdenticalTo(locations[LocNo]))
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break;
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}
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// No matches.
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if (KeepLoc == locations.size())
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return;
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// Keep the smaller location, erase the larger one.
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unsigned EraseLoc = LocNo;
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if (KeepLoc > EraseLoc)
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std::swap(KeepLoc, EraseLoc);
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locations.erase(locations.begin() + EraseLoc);
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// Rewrite values.
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for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
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unsigned v = I.value();
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if (v == EraseLoc)
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I.setValue(KeepLoc); // Coalesce when possible.
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else if (v > EraseLoc)
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I.setValueUnchecked(v-1); // Avoid coalescing with untransformed values.
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}
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}
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void UserValue::mapVirtRegs(LDVImpl *LDV) {
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for (unsigned i = 0, e = locations.size(); i != e; ++i)
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if (locations[i].isReg() &&
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TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
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LDV->mapVirtReg(locations[i].getReg(), this);
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}
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UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset,
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bool IsIndirect, DebugLoc DL) {
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UserValue *&Leader = userVarMap[Var];
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if (Leader) {
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UserValue *UV = Leader->getLeader();
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Leader = UV;
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for (; UV; UV = UV->getNext())
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if (UV->match(Var, Offset, IsIndirect))
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return UV;
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}
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userValues.push_back(
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make_unique<UserValue>(Var, Offset, IsIndirect, DL, allocator));
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UserValue *UV = userValues.back().get();
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Leader = UserValue::merge(Leader, UV);
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return UV;
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}
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void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
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assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs");
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UserValue *&Leader = virtRegToEqClass[VirtReg];
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Leader = UserValue::merge(Leader, EC);
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}
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UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
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if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
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return UV->getLeader();
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return nullptr;
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}
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bool LDVImpl::handleDebugValue(MachineInstr *MI, SlotIndex Idx) {
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// DBG_VALUE loc, offset, variable
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if (MI->getNumOperands() != 3 ||
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!(MI->getOperand(1).isReg() || MI->getOperand(1).isImm()) ||
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!MI->getOperand(2).isMetadata()) {
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DEBUG(dbgs() << "Can't handle " << *MI);
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return false;
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}
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// Get or create the UserValue for (variable,offset).
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bool IsIndirect = MI->isIndirectDebugValue();
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unsigned Offset = IsIndirect ? MI->getOperand(1).getImm() : 0;
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const MDNode *Var = MI->getOperand(2).getMetadata();
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//here.
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UserValue *UV = getUserValue(Var, Offset, IsIndirect, MI->getDebugLoc());
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UV->addDef(Idx, MI->getOperand(0));
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return true;
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}
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bool LDVImpl::collectDebugValues(MachineFunction &mf) {
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bool Changed = false;
|
|
for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
|
|
++MFI) {
|
|
MachineBasicBlock *MBB = MFI;
|
|
for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
|
|
MBBI != MBBE;) {
|
|
if (!MBBI->isDebugValue()) {
|
|
++MBBI;
|
|
continue;
|
|
}
|
|
// DBG_VALUE has no slot index, use the previous instruction instead.
|
|
SlotIndex Idx = MBBI == MBB->begin() ?
|
|
LIS->getMBBStartIdx(MBB) :
|
|
LIS->getInstructionIndex(std::prev(MBBI)).getRegSlot();
|
|
// Handle consecutive DBG_VALUE instructions with the same slot index.
|
|
do {
|
|
if (handleDebugValue(MBBI, Idx)) {
|
|
MBBI = MBB->erase(MBBI);
|
|
Changed = true;
|
|
} else
|
|
++MBBI;
|
|
} while (MBBI != MBBE && MBBI->isDebugValue());
|
|
}
|
|
}
|
|
return Changed;
|
|
}
|
|
|
|
void UserValue::extendDef(SlotIndex Idx, unsigned LocNo,
|
|
LiveRange *LR, const VNInfo *VNI,
|
|
SmallVectorImpl<SlotIndex> *Kills,
|
|
LiveIntervals &LIS, MachineDominatorTree &MDT,
|
|
UserValueScopes &UVS) {
|
|
SmallVector<SlotIndex, 16> Todo;
|
|
Todo.push_back(Idx);
|
|
do {
|
|
SlotIndex Start = Todo.pop_back_val();
|
|
MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
|
|
SlotIndex Stop = LIS.getMBBEndIdx(MBB);
|
|
LocMap::iterator I = locInts.find(Start);
|
|
|
|
// Limit to VNI's live range.
|
|
bool ToEnd = true;
|
|
if (LR && VNI) {
|
|
LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
|
|
if (!Segment || Segment->valno != VNI) {
|
|
if (Kills)
|
|
Kills->push_back(Start);
|
|
continue;
|
|
}
|
|
if (Segment->end < Stop)
|
|
Stop = Segment->end, ToEnd = false;
|
|
}
|
|
|
|
// There could already be a short def at Start.
|
|
if (I.valid() && I.start() <= Start) {
|
|
// Stop when meeting a different location or an already extended interval.
|
|
Start = Start.getNextSlot();
|
|
if (I.value() != LocNo || I.stop() != Start)
|
|
continue;
|
|
// This is a one-slot placeholder. Just skip it.
|
|
++I;
|
|
}
|
|
|
|
// Limited by the next def.
|
|
if (I.valid() && I.start() < Stop)
|
|
Stop = I.start(), ToEnd = false;
|
|
// Limited by VNI's live range.
|
|
else if (!ToEnd && Kills)
|
|
Kills->push_back(Stop);
|
|
|
|
if (Start >= Stop)
|
|
continue;
|
|
|
|
I.insert(Start, Stop, LocNo);
|
|
|
|
// If we extended to the MBB end, propagate down the dominator tree.
|
|
if (!ToEnd)
|
|
continue;
|
|
const std::vector<MachineDomTreeNode*> &Children =
|
|
MDT.getNode(MBB)->getChildren();
|
|
for (unsigned i = 0, e = Children.size(); i != e; ++i) {
|
|
MachineBasicBlock *MBB = Children[i]->getBlock();
|
|
if (UVS.dominates(MBB))
|
|
Todo.push_back(LIS.getMBBStartIdx(MBB));
|
|
}
|
|
} while (!Todo.empty());
|
|
}
|
|
|
|
void
|
|
UserValue::addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
|
|
const SmallVectorImpl<SlotIndex> &Kills,
|
|
SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
|
|
MachineRegisterInfo &MRI, LiveIntervals &LIS) {
|
|
if (Kills.empty())
|
|
return;
|
|
// Don't track copies from physregs, there are too many uses.
|
|
if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
|
|
return;
|
|
|
|
// Collect all the (vreg, valno) pairs that are copies of LI.
|
|
SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
|
|
for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg)) {
|
|
MachineInstr *MI = MO.getParent();
|
|
// Copies of the full value.
|
|
if (MO.getSubReg() || !MI->isCopy())
|
|
continue;
|
|
unsigned DstReg = MI->getOperand(0).getReg();
|
|
|
|
// Don't follow copies to physregs. These are usually setting up call
|
|
// arguments, and the argument registers are always call clobbered. We are
|
|
// better off in the source register which could be a callee-saved register,
|
|
// or it could be spilled.
|
|
if (!TargetRegisterInfo::isVirtualRegister(DstReg))
|
|
continue;
|
|
|
|
// Is LocNo extended to reach this copy? If not, another def may be blocking
|
|
// it, or we are looking at a wrong value of LI.
|
|
SlotIndex Idx = LIS.getInstructionIndex(MI);
|
|
LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
|
|
if (!I.valid() || I.value() != LocNo)
|
|
continue;
|
|
|
|
if (!LIS.hasInterval(DstReg))
|
|
continue;
|
|
LiveInterval *DstLI = &LIS.getInterval(DstReg);
|
|
const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
|
|
assert(DstVNI && DstVNI->def == Idx.getRegSlot() && "Bad copy value");
|
|
CopyValues.push_back(std::make_pair(DstLI, DstVNI));
|
|
}
|
|
|
|
if (CopyValues.empty())
|
|
return;
|
|
|
|
DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI << '\n');
|
|
|
|
// Try to add defs of the copied values for each kill point.
|
|
for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
|
|
SlotIndex Idx = Kills[i];
|
|
for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
|
|
LiveInterval *DstLI = CopyValues[j].first;
|
|
const VNInfo *DstVNI = CopyValues[j].second;
|
|
if (DstLI->getVNInfoAt(Idx) != DstVNI)
|
|
continue;
|
|
// Check that there isn't already a def at Idx
|
|
LocMap::iterator I = locInts.find(Idx);
|
|
if (I.valid() && I.start() <= Idx)
|
|
continue;
|
|
DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #"
|
|
<< DstVNI->id << " in " << *DstLI << '\n');
|
|
MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
|
|
assert(CopyMI && CopyMI->isCopy() && "Bad copy value");
|
|
unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
|
|
I.insert(Idx, Idx.getNextSlot(), LocNo);
|
|
NewDefs.push_back(std::make_pair(Idx, LocNo));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
UserValue::computeIntervals(MachineRegisterInfo &MRI,
|
|
const TargetRegisterInfo &TRI,
|
|
LiveIntervals &LIS,
|
|
MachineDominatorTree &MDT,
|
|
UserValueScopes &UVS) {
|
|
SmallVector<std::pair<SlotIndex, unsigned>, 16> Defs;
|
|
|
|
// Collect all defs to be extended (Skipping undefs).
|
|
for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
|
|
if (I.value() != ~0u)
|
|
Defs.push_back(std::make_pair(I.start(), I.value()));
|
|
|
|
// Extend all defs, and possibly add new ones along the way.
|
|
for (unsigned i = 0; i != Defs.size(); ++i) {
|
|
SlotIndex Idx = Defs[i].first;
|
|
unsigned LocNo = Defs[i].second;
|
|
const MachineOperand &Loc = locations[LocNo];
|
|
|
|
if (!Loc.isReg()) {
|
|
extendDef(Idx, LocNo, nullptr, nullptr, nullptr, LIS, MDT, UVS);
|
|
continue;
|
|
}
|
|
|
|
// Register locations are constrained to where the register value is live.
|
|
if (TargetRegisterInfo::isVirtualRegister(Loc.getReg())) {
|
|
LiveInterval *LI = nullptr;
|
|
const VNInfo *VNI = nullptr;
|
|
if (LIS.hasInterval(Loc.getReg())) {
|
|
LI = &LIS.getInterval(Loc.getReg());
|
|
VNI = LI->getVNInfoAt(Idx);
|
|
}
|
|
SmallVector<SlotIndex, 16> Kills;
|
|
extendDef(Idx, LocNo, LI, VNI, &Kills, LIS, MDT, UVS);
|
|
if (LI)
|
|
addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS);
|
|
continue;
|
|
}
|
|
|
|
// For physregs, use the live range of the first regunit as a guide.
|
|
unsigned Unit = *MCRegUnitIterator(Loc.getReg(), &TRI);
|
|
LiveRange *LR = &LIS.getRegUnit(Unit);
|
|
const VNInfo *VNI = LR->getVNInfoAt(Idx);
|
|
// Don't track copies from physregs, it is too expensive.
|
|
extendDef(Idx, LocNo, LR, VNI, nullptr, LIS, MDT, UVS);
|
|
}
|
|
|
|
// Finally, erase all the undefs.
|
|
for (LocMap::iterator I = locInts.begin(); I.valid();)
|
|
if (I.value() == ~0u)
|
|
I.erase();
|
|
else
|
|
++I;
|
|
}
|
|
|
|
void LDVImpl::computeIntervals() {
|
|
for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
|
|
UserValueScopes UVS(userValues[i]->getDebugLoc(), LS);
|
|
userValues[i]->computeIntervals(MF->getRegInfo(), *TRI, *LIS, *MDT, UVS);
|
|
userValues[i]->mapVirtRegs(this);
|
|
}
|
|
}
|
|
|
|
bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
|
|
clear();
|
|
MF = &mf;
|
|
LIS = &pass.getAnalysis<LiveIntervals>();
|
|
MDT = &pass.getAnalysis<MachineDominatorTree>();
|
|
TRI = mf.getSubtarget().getRegisterInfo();
|
|
LS.initialize(mf);
|
|
DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
|
|
<< mf.getName() << " **********\n");
|
|
|
|
bool Changed = collectDebugValues(mf);
|
|
computeIntervals();
|
|
DEBUG(print(dbgs()));
|
|
ModifiedMF = Changed;
|
|
return Changed;
|
|
}
|
|
|
|
static void removeDebugValues(MachineFunction &mf) {
|
|
for (MachineBasicBlock &MBB : mf) {
|
|
for (auto MBBI = MBB.begin(), MBBE = MBB.end(); MBBI != MBBE; ) {
|
|
if (!MBBI->isDebugValue()) {
|
|
++MBBI;
|
|
continue;
|
|
}
|
|
MBBI = MBB.erase(MBBI);
|
|
}
|
|
}
|
|
}
|
|
|
|
bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
|
|
if (!EnableLDV)
|
|
return false;
|
|
if (!FunctionDIs.count(mf.getFunction())) {
|
|
removeDebugValues(mf);
|
|
return false;
|
|
}
|
|
if (!pImpl)
|
|
pImpl = new LDVImpl(this);
|
|
return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
|
|
}
|
|
|
|
void LiveDebugVariables::releaseMemory() {
|
|
if (pImpl)
|
|
static_cast<LDVImpl*>(pImpl)->clear();
|
|
}
|
|
|
|
LiveDebugVariables::~LiveDebugVariables() {
|
|
if (pImpl)
|
|
delete static_cast<LDVImpl*>(pImpl);
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Live Range Splitting
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
bool
|
|
UserValue::splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
|
|
LiveIntervals& LIS) {
|
|
DEBUG({
|
|
dbgs() << "Splitting Loc" << OldLocNo << '\t';
|
|
print(dbgs(), nullptr);
|
|
});
|
|
bool DidChange = false;
|
|
LocMap::iterator LocMapI;
|
|
LocMapI.setMap(locInts);
|
|
for (unsigned i = 0; i != NewRegs.size(); ++i) {
|
|
LiveInterval *LI = &LIS.getInterval(NewRegs[i]);
|
|
if (LI->empty())
|
|
continue;
|
|
|
|
// Don't allocate the new LocNo until it is needed.
|
|
unsigned NewLocNo = ~0u;
|
|
|
|
// Iterate over the overlaps between locInts and LI.
|
|
LocMapI.find(LI->beginIndex());
|
|
if (!LocMapI.valid())
|
|
continue;
|
|
LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
|
|
LiveInterval::iterator LIE = LI->end();
|
|
while (LocMapI.valid() && LII != LIE) {
|
|
// At this point, we know that LocMapI.stop() > LII->start.
|
|
LII = LI->advanceTo(LII, LocMapI.start());
|
|
if (LII == LIE)
|
|
break;
|
|
|
|
// Now LII->end > LocMapI.start(). Do we have an overlap?
|
|
if (LocMapI.value() == OldLocNo && LII->start < LocMapI.stop()) {
|
|
// Overlapping correct location. Allocate NewLocNo now.
|
|
if (NewLocNo == ~0u) {
|
|
MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
|
|
MO.setSubReg(locations[OldLocNo].getSubReg());
|
|
NewLocNo = getLocationNo(MO);
|
|
DidChange = true;
|
|
}
|
|
|
|
SlotIndex LStart = LocMapI.start();
|
|
SlotIndex LStop = LocMapI.stop();
|
|
|
|
// Trim LocMapI down to the LII overlap.
|
|
if (LStart < LII->start)
|
|
LocMapI.setStartUnchecked(LII->start);
|
|
if (LStop > LII->end)
|
|
LocMapI.setStopUnchecked(LII->end);
|
|
|
|
// Change the value in the overlap. This may trigger coalescing.
|
|
LocMapI.setValue(NewLocNo);
|
|
|
|
// Re-insert any removed OldLocNo ranges.
|
|
if (LStart < LocMapI.start()) {
|
|
LocMapI.insert(LStart, LocMapI.start(), OldLocNo);
|
|
++LocMapI;
|
|
assert(LocMapI.valid() && "Unexpected coalescing");
|
|
}
|
|
if (LStop > LocMapI.stop()) {
|
|
++LocMapI;
|
|
LocMapI.insert(LII->end, LStop, OldLocNo);
|
|
--LocMapI;
|
|
}
|
|
}
|
|
|
|
// Advance to the next overlap.
|
|
if (LII->end < LocMapI.stop()) {
|
|
if (++LII == LIE)
|
|
break;
|
|
LocMapI.advanceTo(LII->start);
|
|
} else {
|
|
++LocMapI;
|
|
if (!LocMapI.valid())
|
|
break;
|
|
LII = LI->advanceTo(LII, LocMapI.start());
|
|
}
|
|
}
|
|
}
|
|
|
|
// Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
|
|
locations.erase(locations.begin() + OldLocNo);
|
|
LocMapI.goToBegin();
|
|
while (LocMapI.valid()) {
|
|
unsigned v = LocMapI.value();
|
|
if (v == OldLocNo) {
|
|
DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'
|
|
<< LocMapI.stop() << ")\n");
|
|
LocMapI.erase();
|
|
} else {
|
|
if (v > OldLocNo)
|
|
LocMapI.setValueUnchecked(v-1);
|
|
++LocMapI;
|
|
}
|
|
}
|
|
|
|
DEBUG({dbgs() << "Split result: \t"; print(dbgs(), nullptr);});
|
|
return DidChange;
|
|
}
|
|
|
|
bool
|
|
UserValue::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
|
|
LiveIntervals &LIS) {
|
|
bool DidChange = false;
|
|
// Split locations referring to OldReg. Iterate backwards so splitLocation can
|
|
// safely erase unused locations.
|
|
for (unsigned i = locations.size(); i ; --i) {
|
|
unsigned LocNo = i-1;
|
|
const MachineOperand *Loc = &locations[LocNo];
|
|
if (!Loc->isReg() || Loc->getReg() != OldReg)
|
|
continue;
|
|
DidChange |= splitLocation(LocNo, NewRegs, LIS);
|
|
}
|
|
return DidChange;
|
|
}
|
|
|
|
void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs) {
|
|
bool DidChange = false;
|
|
for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
|
|
DidChange |= UV->splitRegister(OldReg, NewRegs, *LIS);
|
|
|
|
if (!DidChange)
|
|
return;
|
|
|
|
// Map all of the new virtual registers.
|
|
UserValue *UV = lookupVirtReg(OldReg);
|
|
for (unsigned i = 0; i != NewRegs.size(); ++i)
|
|
mapVirtReg(NewRegs[i], UV);
|
|
}
|
|
|
|
void LiveDebugVariables::
|
|
splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, LiveIntervals &LIS) {
|
|
if (pImpl)
|
|
static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
|
|
}
|
|
|
|
void
|
|
UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
|
|
// Iterate over locations in reverse makes it easier to handle coalescing.
|
|
for (unsigned i = locations.size(); i ; --i) {
|
|
unsigned LocNo = i-1;
|
|
MachineOperand &Loc = locations[LocNo];
|
|
// Only virtual registers are rewritten.
|
|
if (!Loc.isReg() || !Loc.getReg() ||
|
|
!TargetRegisterInfo::isVirtualRegister(Loc.getReg()))
|
|
continue;
|
|
unsigned VirtReg = Loc.getReg();
|
|
if (VRM.isAssignedReg(VirtReg) &&
|
|
TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
|
|
// This can create a %noreg operand in rare cases when the sub-register
|
|
// index is no longer available. That means the user value is in a
|
|
// non-existent sub-register, and %noreg is exactly what we want.
|
|
Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
|
|
} else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
|
|
// FIXME: Translate SubIdx to a stackslot offset.
|
|
Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
|
|
} else {
|
|
Loc.setReg(0);
|
|
Loc.setSubReg(0);
|
|
}
|
|
coalesceLocation(LocNo);
|
|
}
|
|
}
|
|
|
|
/// findInsertLocation - Find an iterator for inserting a DBG_VALUE
|
|
/// instruction.
|
|
static MachineBasicBlock::iterator
|
|
findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
|
|
LiveIntervals &LIS) {
|
|
SlotIndex Start = LIS.getMBBStartIdx(MBB);
|
|
Idx = Idx.getBaseIndex();
|
|
|
|
// Try to find an insert location by going backwards from Idx.
|
|
MachineInstr *MI;
|
|
while (!(MI = LIS.getInstructionFromIndex(Idx))) {
|
|
// We've reached the beginning of MBB.
|
|
if (Idx == Start) {
|
|
MachineBasicBlock::iterator I = MBB->SkipPHIsAndLabels(MBB->begin());
|
|
return I;
|
|
}
|
|
Idx = Idx.getPrevIndex();
|
|
}
|
|
|
|
// Don't insert anything after the first terminator, though.
|
|
return MI->isTerminator() ? MBB->getFirstTerminator() :
|
|
std::next(MachineBasicBlock::iterator(MI));
|
|
}
|
|
|
|
DebugLoc UserValue::findDebugLoc() {
|
|
DebugLoc D = dl;
|
|
dl = DebugLoc();
|
|
return D;
|
|
}
|
|
void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
|
|
unsigned LocNo,
|
|
LiveIntervals &LIS,
|
|
const TargetInstrInfo &TII) {
|
|
MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
|
|
MachineOperand &Loc = locations[LocNo];
|
|
++NumInsertedDebugValues;
|
|
|
|
if (Loc.isReg())
|
|
BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
|
|
IsIndirect, Loc.getReg(), offset, variable);
|
|
else
|
|
BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
|
|
.addOperand(Loc).addImm(offset).addMetadata(variable);
|
|
}
|
|
|
|
void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
|
|
const TargetInstrInfo &TII) {
|
|
MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
|
|
|
|
for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
|
|
SlotIndex Start = I.start();
|
|
SlotIndex Stop = I.stop();
|
|
unsigned LocNo = I.value();
|
|
DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << LocNo);
|
|
MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start);
|
|
SlotIndex MBBEnd = LIS.getMBBEndIdx(MBB);
|
|
|
|
DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
|
|
insertDebugValue(MBB, Start, LocNo, LIS, TII);
|
|
// This interval may span multiple basic blocks.
|
|
// Insert a DBG_VALUE into each one.
|
|
while(Stop > MBBEnd) {
|
|
// Move to the next block.
|
|
Start = MBBEnd;
|
|
if (++MBB == MFEnd)
|
|
break;
|
|
MBBEnd = LIS.getMBBEndIdx(MBB);
|
|
DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
|
|
insertDebugValue(MBB, Start, LocNo, LIS, TII);
|
|
}
|
|
DEBUG(dbgs() << '\n');
|
|
if (MBB == MFEnd)
|
|
break;
|
|
|
|
++I;
|
|
}
|
|
}
|
|
|
|
void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
|
|
DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n");
|
|
if (!MF)
|
|
return;
|
|
const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
|
|
for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
|
|
DEBUG(userValues[i]->print(dbgs(), &MF->getTarget()));
|
|
userValues[i]->rewriteLocations(*VRM, *TRI);
|
|
userValues[i]->emitDebugValues(VRM, *LIS, *TII);
|
|
}
|
|
EmitDone = true;
|
|
}
|
|
|
|
void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
|
|
if (pImpl)
|
|
static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
|
|
}
|
|
|
|
bool LiveDebugVariables::doInitialization(Module &M) {
|
|
FunctionDIs = makeSubprogramMap(M);
|
|
return Pass::doInitialization(M);
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
void LiveDebugVariables::dump() {
|
|
if (pImpl)
|
|
static_cast<LDVImpl*>(pImpl)->print(dbgs());
|
|
}
|
|
#endif
|