File: | src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/CodeGen/LiveDebugValues/VarLocBasedImpl.cpp |
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1 | //===- VarLocBasedImpl.cpp - Tracking Debug Value MIs with VarLoc class----===// |
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 | /// \file VarLocBasedImpl.cpp |
10 | /// |
11 | /// LiveDebugValues is an optimistic "available expressions" dataflow |
12 | /// algorithm. The set of expressions is the set of machine locations |
13 | /// (registers, spill slots, constants) that a variable fragment might be |
14 | /// located, qualified by a DIExpression and indirect-ness flag, while each |
15 | /// variable is identified by a DebugVariable object. The availability of an |
16 | /// expression begins when a DBG_VALUE instruction specifies the location of a |
17 | /// DebugVariable, and continues until that location is clobbered or |
18 | /// re-specified by a different DBG_VALUE for the same DebugVariable. |
19 | /// |
20 | /// The output of LiveDebugValues is additional DBG_VALUE instructions, |
21 | /// placed to extend variable locations as far they're available. This file |
22 | /// and the VarLocBasedLDV class is an implementation that explicitly tracks |
23 | /// locations, using the VarLoc class. |
24 | /// |
25 | /// The canonical "available expressions" problem doesn't have expression |
26 | /// clobbering, instead when a variable is re-assigned, any expressions using |
27 | /// that variable get invalidated. LiveDebugValues can map onto "available |
28 | /// expressions" by having every register represented by a variable, which is |
29 | /// used in an expression that becomes available at a DBG_VALUE instruction. |
30 | /// When the register is clobbered, its variable is effectively reassigned, and |
31 | /// expressions computed from it become unavailable. A similar construct is |
32 | /// needed when a DebugVariable has its location re-specified, to invalidate |
33 | /// all other locations for that DebugVariable. |
34 | /// |
35 | /// Using the dataflow analysis to compute the available expressions, we create |
36 | /// a DBG_VALUE at the beginning of each block where the expression is |
37 | /// live-in. This propagates variable locations into every basic block where |
38 | /// the location can be determined, rather than only having DBG_VALUEs in blocks |
39 | /// where locations are specified due to an assignment or some optimization. |
40 | /// Movements of values between registers and spill slots are annotated with |
41 | /// DBG_VALUEs too to track variable values bewteen locations. All this allows |
42 | /// DbgEntityHistoryCalculator to focus on only the locations within individual |
43 | /// blocks, facilitating testing and improving modularity. |
44 | /// |
45 | /// We follow an optimisic dataflow approach, with this lattice: |
46 | /// |
47 | /// \verbatim |
48 | /// ┬ "Unknown" |
49 | /// | |
50 | /// v |
51 | /// True |
52 | /// | |
53 | /// v |
54 | /// ⊥ False |
55 | /// \endverbatim With "True" signifying that the expression is available (and |
56 | /// thus a DebugVariable's location is the corresponding register), while |
57 | /// "False" signifies that the expression is unavailable. "Unknown"s never |
58 | /// survive to the end of the analysis (see below). |
59 | /// |
60 | /// Formally, all DebugVariable locations that are live-out of a block are |
61 | /// initialized to \top. A blocks live-in values take the meet of the lattice |
62 | /// value for every predecessors live-outs, except for the entry block, where |
63 | /// all live-ins are \bot. The usual dataflow propagation occurs: the transfer |
64 | /// function for a block assigns an expression for a DebugVariable to be "True" |
65 | /// if a DBG_VALUE in the block specifies it; "False" if the location is |
66 | /// clobbered; or the live-in value if it is unaffected by the block. We |
67 | /// visit each block in reverse post order until a fixedpoint is reached. The |
68 | /// solution produced is maximal. |
69 | /// |
70 | /// Intuitively, we start by assuming that every expression / variable location |
71 | /// is at least "True", and then propagate "False" from the entry block and any |
72 | /// clobbers until there are no more changes to make. This gives us an accurate |
73 | /// solution because all incorrect locations will have a "False" propagated into |
74 | /// them. It also gives us a solution that copes well with loops by assuming |
75 | /// that variable locations are live-through every loop, and then removing those |
76 | /// that are not through dataflow. |
77 | /// |
78 | /// Within LiveDebugValues: each variable location is represented by a |
79 | /// VarLoc object that identifies the source variable, the set of |
80 | /// machine-locations that currently describe it (a single location for |
81 | /// DBG_VALUE or multiple for DBG_VALUE_LIST), and the DBG_VALUE inst that |
82 | /// specifies the location. Each VarLoc is indexed in the (function-scope) \p |
83 | /// VarLocMap, giving each VarLoc a set of unique indexes, each of which |
84 | /// corresponds to one of the VarLoc's machine-locations and can be used to |
85 | /// lookup the VarLoc in the VarLocMap. Rather than operate directly on machine |
86 | /// locations, the dataflow analysis in this pass identifies locations by their |
87 | /// indices in the VarLocMap, meaning all the variable locations in a block can |
88 | /// be described by a sparse vector of VarLocMap indicies. |
89 | /// |
90 | /// All the storage for the dataflow analysis is local to the ExtendRanges |
91 | /// method and passed down to helper methods. "OutLocs" and "InLocs" record the |
92 | /// in and out lattice values for each block. "OpenRanges" maintains a list of |
93 | /// variable locations and, with the "process" method, evaluates the transfer |
94 | /// function of each block. "flushPendingLocs" installs debug value instructions |
95 | /// for each live-in location at the start of blocks, while "Transfers" records |
96 | /// transfers of values between machine-locations. |
97 | /// |
98 | /// We avoid explicitly representing the "Unknown" (\top) lattice value in the |
99 | /// implementation. Instead, unvisited blocks implicitly have all lattice |
100 | /// values set as "Unknown". After being visited, there will be path back to |
101 | /// the entry block where the lattice value is "False", and as the transfer |
102 | /// function cannot make new "Unknown" locations, there are no scenarios where |
103 | /// a block can have an "Unknown" location after being visited. Similarly, we |
104 | /// don't enumerate all possible variable locations before exploring the |
105 | /// function: when a new location is discovered, all blocks previously explored |
106 | /// were implicitly "False" but unrecorded, and become explicitly "False" when |
107 | /// a new VarLoc is created with its bit not set in predecessor InLocs or |
108 | /// OutLocs. |
109 | /// |
110 | //===----------------------------------------------------------------------===// |
111 | |
112 | #include "LiveDebugValues.h" |
113 | |
114 | #include "llvm/ADT/CoalescingBitVector.h" |
115 | #include "llvm/ADT/DenseMap.h" |
116 | #include "llvm/ADT/PostOrderIterator.h" |
117 | #include "llvm/ADT/SmallPtrSet.h" |
118 | #include "llvm/ADT/SmallSet.h" |
119 | #include "llvm/ADT/SmallVector.h" |
120 | #include "llvm/ADT/Statistic.h" |
121 | #include "llvm/ADT/UniqueVector.h" |
122 | #include "llvm/CodeGen/LexicalScopes.h" |
123 | #include "llvm/CodeGen/MachineBasicBlock.h" |
124 | #include "llvm/CodeGen/MachineFrameInfo.h" |
125 | #include "llvm/CodeGen/MachineFunction.h" |
126 | #include "llvm/CodeGen/MachineFunctionPass.h" |
127 | #include "llvm/CodeGen/MachineInstr.h" |
128 | #include "llvm/CodeGen/MachineInstrBuilder.h" |
129 | #include "llvm/CodeGen/MachineMemOperand.h" |
130 | #include "llvm/CodeGen/MachineOperand.h" |
131 | #include "llvm/CodeGen/PseudoSourceValue.h" |
132 | #include "llvm/CodeGen/RegisterScavenging.h" |
133 | #include "llvm/CodeGen/TargetFrameLowering.h" |
134 | #include "llvm/CodeGen/TargetInstrInfo.h" |
135 | #include "llvm/CodeGen/TargetLowering.h" |
136 | #include "llvm/CodeGen/TargetPassConfig.h" |
137 | #include "llvm/CodeGen/TargetRegisterInfo.h" |
138 | #include "llvm/CodeGen/TargetSubtargetInfo.h" |
139 | #include "llvm/Config/llvm-config.h" |
140 | #include "llvm/IR/DIBuilder.h" |
141 | #include "llvm/IR/DebugInfoMetadata.h" |
142 | #include "llvm/IR/DebugLoc.h" |
143 | #include "llvm/IR/Function.h" |
144 | #include "llvm/IR/Module.h" |
145 | #include "llvm/InitializePasses.h" |
146 | #include "llvm/MC/MCRegisterInfo.h" |
147 | #include "llvm/Pass.h" |
148 | #include "llvm/Support/Casting.h" |
149 | #include "llvm/Support/Compiler.h" |
150 | #include "llvm/Support/Debug.h" |
151 | #include "llvm/Support/TypeSize.h" |
152 | #include "llvm/Support/raw_ostream.h" |
153 | #include "llvm/Target/TargetMachine.h" |
154 | #include <algorithm> |
155 | #include <cassert> |
156 | #include <cstdint> |
157 | #include <functional> |
158 | #include <queue> |
159 | #include <tuple> |
160 | #include <utility> |
161 | #include <vector> |
162 | |
163 | using namespace llvm; |
164 | |
165 | #define DEBUG_TYPE"livedebugvalues" "livedebugvalues" |
166 | |
167 | STATISTIC(NumInserted, "Number of DBG_VALUE instructions inserted")static llvm::Statistic NumInserted = {"livedebugvalues", "NumInserted" , "Number of DBG_VALUE instructions inserted"}; |
168 | |
169 | // Options to prevent pathological compile-time behavior. If InputBBLimit and |
170 | // InputDbgValueLimit are both exceeded, range extension is disabled. |
171 | static cl::opt<unsigned> InputBBLimit( |
172 | "livedebugvalues-input-bb-limit", |
173 | cl::desc("Maximum input basic blocks before DBG_VALUE limit applies"), |
174 | cl::init(10000), cl::Hidden); |
175 | static cl::opt<unsigned> InputDbgValueLimit( |
176 | "livedebugvalues-input-dbg-value-limit", |
177 | cl::desc( |
178 | "Maximum input DBG_VALUE insts supported by debug range extension"), |
179 | cl::init(50000), cl::Hidden); |
180 | |
181 | /// If \p Op is a stack or frame register return true, otherwise return false. |
182 | /// This is used to avoid basing the debug entry values on the registers, since |
183 | /// we do not support it at the moment. |
184 | static bool isRegOtherThanSPAndFP(const MachineOperand &Op, |
185 | const MachineInstr &MI, |
186 | const TargetRegisterInfo *TRI) { |
187 | if (!Op.isReg()) |
188 | return false; |
189 | |
190 | const MachineFunction *MF = MI.getParent()->getParent(); |
191 | const TargetLowering *TLI = MF->getSubtarget().getTargetLowering(); |
192 | Register SP = TLI->getStackPointerRegisterToSaveRestore(); |
193 | Register FP = TRI->getFrameRegister(*MF); |
194 | Register Reg = Op.getReg(); |
195 | |
196 | return Reg && Reg != SP && Reg != FP; |
197 | } |
198 | |
199 | namespace { |
200 | |
201 | // Max out the number of statically allocated elements in DefinedRegsSet, as |
202 | // this prevents fallback to std::set::count() operations. |
203 | using DefinedRegsSet = SmallSet<Register, 32>; |
204 | |
205 | // The IDs in this set correspond to MachineLocs in VarLocs, as well as VarLocs |
206 | // that represent Entry Values; every VarLoc in the set will also appear |
207 | // exactly once at Location=0. |
208 | // As a result, each VarLoc may appear more than once in this "set", but each |
209 | // range corresponding to a Reg, SpillLoc, or EntryValue type will still be a |
210 | // "true" set (i.e. each VarLoc may appear only once), and the range Location=0 |
211 | // is the set of all VarLocs. |
212 | using VarLocSet = CoalescingBitVector<uint64_t>; |
213 | |
214 | /// A type-checked pair of {Register Location (or 0), Index}, used to index |
215 | /// into a \ref VarLocMap. This can be efficiently converted to a 64-bit int |
216 | /// for insertion into a \ref VarLocSet, and efficiently converted back. The |
217 | /// type-checker helps ensure that the conversions aren't lossy. |
218 | /// |
219 | /// Why encode a location /into/ the VarLocMap index? This makes it possible |
220 | /// to find the open VarLocs killed by a register def very quickly. This is a |
221 | /// performance-critical operation for LiveDebugValues. |
222 | struct LocIndex { |
223 | using u32_location_t = uint32_t; |
224 | using u32_index_t = uint32_t; |
225 | |
226 | u32_location_t Location; // Physical registers live in the range [1;2^30) (see |
227 | // \ref MCRegister), so we have plenty of range left |
228 | // here to encode non-register locations. |
229 | u32_index_t Index; |
230 | |
231 | /// The location that has an entry for every VarLoc in the map. |
232 | static constexpr u32_location_t kUniversalLocation = 0; |
233 | |
234 | /// The first location that is reserved for VarLocs with locations of kind |
235 | /// RegisterKind. |
236 | static constexpr u32_location_t kFirstRegLocation = 1; |
237 | |
238 | /// The first location greater than 0 that is not reserved for VarLocs with |
239 | /// locations of kind RegisterKind. |
240 | static constexpr u32_location_t kFirstInvalidRegLocation = 1 << 30; |
241 | |
242 | /// A special location reserved for VarLocs with locations of kind |
243 | /// SpillLocKind. |
244 | static constexpr u32_location_t kSpillLocation = kFirstInvalidRegLocation; |
245 | |
246 | /// A special location reserved for VarLocs of kind EntryValueBackupKind and |
247 | /// EntryValueCopyBackupKind. |
248 | static constexpr u32_location_t kEntryValueBackupLocation = |
249 | kFirstInvalidRegLocation + 1; |
250 | |
251 | LocIndex(u32_location_t Location, u32_index_t Index) |
252 | : Location(Location), Index(Index) {} |
253 | |
254 | uint64_t getAsRawInteger() const { |
255 | return (static_cast<uint64_t>(Location) << 32) | Index; |
256 | } |
257 | |
258 | template<typename IntT> static LocIndex fromRawInteger(IntT ID) { |
259 | static_assert(std::is_unsigned<IntT>::value && |
260 | sizeof(ID) == sizeof(uint64_t), |
261 | "Cannot convert raw integer to LocIndex"); |
262 | return {static_cast<u32_location_t>(ID >> 32), |
263 | static_cast<u32_index_t>(ID)}; |
264 | } |
265 | |
266 | /// Get the start of the interval reserved for VarLocs of kind RegisterKind |
267 | /// which reside in \p Reg. The end is at rawIndexForReg(Reg+1)-1. |
268 | static uint64_t rawIndexForReg(Register Reg) { |
269 | return LocIndex(Reg, 0).getAsRawInteger(); |
270 | } |
271 | |
272 | /// Return a range covering all set indices in the interval reserved for |
273 | /// \p Location in \p Set. |
274 | static auto indexRangeForLocation(const VarLocSet &Set, |
275 | u32_location_t Location) { |
276 | uint64_t Start = LocIndex(Location, 0).getAsRawInteger(); |
277 | uint64_t End = LocIndex(Location + 1, 0).getAsRawInteger(); |
278 | return Set.half_open_range(Start, End); |
279 | } |
280 | }; |
281 | |
282 | // Simple Set for storing all the VarLoc Indices at a Location bucket. |
283 | using VarLocsInRange = SmallSet<LocIndex::u32_index_t, 32>; |
284 | // Vector of all `LocIndex`s for a given VarLoc; the same Location should not |
285 | // appear in any two of these, as each VarLoc appears at most once in any |
286 | // Location bucket. |
287 | using LocIndices = SmallVector<LocIndex, 2>; |
288 | |
289 | class VarLocBasedLDV : public LDVImpl { |
290 | private: |
291 | const TargetRegisterInfo *TRI; |
292 | const TargetInstrInfo *TII; |
293 | const TargetFrameLowering *TFI; |
294 | TargetPassConfig *TPC; |
295 | BitVector CalleeSavedRegs; |
296 | LexicalScopes LS; |
297 | VarLocSet::Allocator Alloc; |
298 | |
299 | enum struct TransferKind { TransferCopy, TransferSpill, TransferRestore }; |
300 | |
301 | using FragmentInfo = DIExpression::FragmentInfo; |
302 | using OptFragmentInfo = Optional<DIExpression::FragmentInfo>; |
303 | |
304 | /// A pair of debug variable and value location. |
305 | struct VarLoc { |
306 | // The location at which a spilled variable resides. It consists of a |
307 | // register and an offset. |
308 | struct SpillLoc { |
309 | unsigned SpillBase; |
310 | StackOffset SpillOffset; |
311 | bool operator==(const SpillLoc &Other) const { |
312 | return SpillBase == Other.SpillBase && SpillOffset == Other.SpillOffset; |
313 | } |
314 | bool operator!=(const SpillLoc &Other) const { |
315 | return !(*this == Other); |
316 | } |
317 | }; |
318 | |
319 | /// Identity of the variable at this location. |
320 | const DebugVariable Var; |
321 | |
322 | /// The expression applied to this location. |
323 | const DIExpression *Expr; |
324 | |
325 | /// DBG_VALUE to clone var/expr information from if this location |
326 | /// is moved. |
327 | const MachineInstr &MI; |
328 | |
329 | enum class MachineLocKind { |
330 | InvalidKind = 0, |
331 | RegisterKind, |
332 | SpillLocKind, |
333 | ImmediateKind |
334 | }; |
335 | |
336 | enum class EntryValueLocKind { |
337 | NonEntryValueKind = 0, |
338 | EntryValueKind, |
339 | EntryValueBackupKind, |
340 | EntryValueCopyBackupKind |
341 | } EVKind; |
342 | |
343 | /// The value location. Stored separately to avoid repeatedly |
344 | /// extracting it from MI. |
345 | union MachineLocValue { |
346 | uint64_t RegNo; |
347 | SpillLoc SpillLocation; |
348 | uint64_t Hash; |
349 | int64_t Immediate; |
350 | const ConstantFP *FPImm; |
351 | const ConstantInt *CImm; |
352 | MachineLocValue() : Hash(0) {} |
353 | }; |
354 | |
355 | /// A single machine location; its Kind is either a register, spill |
356 | /// location, or immediate value. |
357 | /// If the VarLoc is not a NonEntryValueKind, then it will use only a |
358 | /// single MachineLoc of RegisterKind. |
359 | struct MachineLoc { |
360 | MachineLocKind Kind; |
361 | MachineLocValue Value; |
362 | bool operator==(const MachineLoc &Other) const { |
363 | if (Kind != Other.Kind) |
364 | return false; |
365 | switch (Kind) { |
366 | case MachineLocKind::SpillLocKind: |
367 | return Value.SpillLocation == Other.Value.SpillLocation; |
368 | case MachineLocKind::RegisterKind: |
369 | case MachineLocKind::ImmediateKind: |
370 | return Value.Hash == Other.Value.Hash; |
371 | default: |
372 | llvm_unreachable("Invalid kind")__builtin_unreachable(); |
373 | } |
374 | } |
375 | bool operator<(const MachineLoc &Other) const { |
376 | switch (Kind) { |
377 | case MachineLocKind::SpillLocKind: |
378 | return std::make_tuple( |
379 | Kind, Value.SpillLocation.SpillBase, |
380 | Value.SpillLocation.SpillOffset.getFixed(), |
381 | Value.SpillLocation.SpillOffset.getScalable()) < |
382 | std::make_tuple( |
383 | Other.Kind, Other.Value.SpillLocation.SpillBase, |
384 | Other.Value.SpillLocation.SpillOffset.getFixed(), |
385 | Other.Value.SpillLocation.SpillOffset.getScalable()); |
386 | case MachineLocKind::RegisterKind: |
387 | case MachineLocKind::ImmediateKind: |
388 | return std::tie(Kind, Value.Hash) < |
389 | std::tie(Other.Kind, Other.Value.Hash); |
390 | default: |
391 | llvm_unreachable("Invalid kind")__builtin_unreachable(); |
392 | } |
393 | } |
394 | }; |
395 | |
396 | /// The set of machine locations used to determine the variable's value, in |
397 | /// conjunction with Expr. Initially populated with MI's debug operands, |
398 | /// but may be transformed independently afterwards. |
399 | SmallVector<MachineLoc, 8> Locs; |
400 | /// Used to map the index of each location in Locs back to the index of its |
401 | /// original debug operand in MI. Used when multiple location operands are |
402 | /// coalesced and the original MI's operands need to be accessed while |
403 | /// emitting a debug value. |
404 | SmallVector<unsigned, 8> OrigLocMap; |
405 | |
406 | VarLoc(const MachineInstr &MI, LexicalScopes &LS) |
407 | : Var(MI.getDebugVariable(), MI.getDebugExpression(), |
408 | MI.getDebugLoc()->getInlinedAt()), |
409 | Expr(MI.getDebugExpression()), MI(MI), |
410 | EVKind(EntryValueLocKind::NonEntryValueKind) { |
411 | assert(MI.isDebugValue() && "not a DBG_VALUE")((void)0); |
412 | assert((MI.isDebugValueList() || MI.getNumOperands() == 4) &&((void)0) |
413 | "malformed DBG_VALUE")((void)0); |
414 | for (const MachineOperand &Op : MI.debug_operands()) { |
415 | MachineLoc ML = GetLocForOp(Op); |
416 | auto It = find(Locs, ML); |
417 | if (It == Locs.end()) { |
418 | Locs.push_back(ML); |
419 | OrigLocMap.push_back(MI.getDebugOperandIndex(&Op)); |
420 | } else { |
421 | // ML duplicates an element in Locs; replace references to Op |
422 | // with references to the duplicating element. |
423 | unsigned OpIdx = Locs.size(); |
424 | unsigned DuplicatingIdx = std::distance(Locs.begin(), It); |
425 | Expr = DIExpression::replaceArg(Expr, OpIdx, DuplicatingIdx); |
426 | } |
427 | } |
428 | |
429 | // We create the debug entry values from the factory functions rather |
430 | // than from this ctor. |
431 | assert(EVKind != EntryValueLocKind::EntryValueKind &&((void)0) |
432 | !isEntryBackupLoc())((void)0); |
433 | } |
434 | |
435 | static MachineLoc GetLocForOp(const MachineOperand &Op) { |
436 | MachineLocKind Kind; |
437 | MachineLocValue Loc; |
438 | if (Op.isReg()) { |
439 | Kind = MachineLocKind::RegisterKind; |
440 | Loc.RegNo = Op.getReg(); |
441 | } else if (Op.isImm()) { |
442 | Kind = MachineLocKind::ImmediateKind; |
443 | Loc.Immediate = Op.getImm(); |
444 | } else if (Op.isFPImm()) { |
445 | Kind = MachineLocKind::ImmediateKind; |
446 | Loc.FPImm = Op.getFPImm(); |
447 | } else if (Op.isCImm()) { |
448 | Kind = MachineLocKind::ImmediateKind; |
449 | Loc.CImm = Op.getCImm(); |
450 | } else |
451 | llvm_unreachable("Invalid Op kind for MachineLoc.")__builtin_unreachable(); |
452 | return {Kind, Loc}; |
453 | } |
454 | |
455 | /// Take the variable and machine-location in DBG_VALUE MI, and build an |
456 | /// entry location using the given expression. |
457 | static VarLoc CreateEntryLoc(const MachineInstr &MI, LexicalScopes &LS, |
458 | const DIExpression *EntryExpr, Register Reg) { |
459 | VarLoc VL(MI, LS); |
460 | assert(VL.Locs.size() == 1 &&((void)0) |
461 | VL.Locs[0].Kind == MachineLocKind::RegisterKind)((void)0); |
462 | VL.EVKind = EntryValueLocKind::EntryValueKind; |
463 | VL.Expr = EntryExpr; |
464 | VL.Locs[0].Value.RegNo = Reg; |
465 | return VL; |
466 | } |
467 | |
468 | /// Take the variable and machine-location from the DBG_VALUE (from the |
469 | /// function entry), and build an entry value backup location. The backup |
470 | /// location will turn into the normal location if the backup is valid at |
471 | /// the time of the primary location clobbering. |
472 | static VarLoc CreateEntryBackupLoc(const MachineInstr &MI, |
473 | LexicalScopes &LS, |
474 | const DIExpression *EntryExpr) { |
475 | VarLoc VL(MI, LS); |
476 | assert(VL.Locs.size() == 1 &&((void)0) |
477 | VL.Locs[0].Kind == MachineLocKind::RegisterKind)((void)0); |
478 | VL.EVKind = EntryValueLocKind::EntryValueBackupKind; |
479 | VL.Expr = EntryExpr; |
480 | return VL; |
481 | } |
482 | |
483 | /// Take the variable and machine-location from the DBG_VALUE (from the |
484 | /// function entry), and build a copy of an entry value backup location by |
485 | /// setting the register location to NewReg. |
486 | static VarLoc CreateEntryCopyBackupLoc(const MachineInstr &MI, |
487 | LexicalScopes &LS, |
488 | const DIExpression *EntryExpr, |
489 | Register NewReg) { |
490 | VarLoc VL(MI, LS); |
491 | assert(VL.Locs.size() == 1 &&((void)0) |
492 | VL.Locs[0].Kind == MachineLocKind::RegisterKind)((void)0); |
493 | VL.EVKind = EntryValueLocKind::EntryValueCopyBackupKind; |
494 | VL.Expr = EntryExpr; |
495 | VL.Locs[0].Value.RegNo = NewReg; |
496 | return VL; |
497 | } |
498 | |
499 | /// Copy the register location in DBG_VALUE MI, updating the register to |
500 | /// be NewReg. |
501 | static VarLoc CreateCopyLoc(const VarLoc &OldVL, const MachineLoc &OldML, |
502 | Register NewReg) { |
503 | VarLoc VL = OldVL; |
504 | for (size_t I = 0, E = VL.Locs.size(); I < E; ++I) |
505 | if (VL.Locs[I] == OldML) { |
506 | VL.Locs[I].Kind = MachineLocKind::RegisterKind; |
507 | VL.Locs[I].Value.RegNo = NewReg; |
508 | return VL; |
509 | } |
510 | llvm_unreachable("Should have found OldML in new VarLoc.")__builtin_unreachable(); |
511 | } |
512 | |
513 | /// Take the variable described by DBG_VALUE* MI, and create a VarLoc |
514 | /// locating it in the specified spill location. |
515 | static VarLoc CreateSpillLoc(const VarLoc &OldVL, const MachineLoc &OldML, |
516 | unsigned SpillBase, StackOffset SpillOffset) { |
517 | VarLoc VL = OldVL; |
518 | for (int I = 0, E = VL.Locs.size(); I < E; ++I) |
519 | if (VL.Locs[I] == OldML) { |
520 | VL.Locs[I].Kind = MachineLocKind::SpillLocKind; |
521 | VL.Locs[I].Value.SpillLocation = {SpillBase, SpillOffset}; |
522 | return VL; |
523 | } |
524 | llvm_unreachable("Should have found OldML in new VarLoc.")__builtin_unreachable(); |
525 | } |
526 | |
527 | /// Create a DBG_VALUE representing this VarLoc in the given function. |
528 | /// Copies variable-specific information such as DILocalVariable and |
529 | /// inlining information from the original DBG_VALUE instruction, which may |
530 | /// have been several transfers ago. |
531 | MachineInstr *BuildDbgValue(MachineFunction &MF) const { |
532 | assert(!isEntryBackupLoc() &&((void)0) |
533 | "Tried to produce DBG_VALUE for backup VarLoc")((void)0); |
534 | const DebugLoc &DbgLoc = MI.getDebugLoc(); |
535 | bool Indirect = MI.isIndirectDebugValue(); |
536 | const auto &IID = MI.getDesc(); |
537 | const DILocalVariable *Var = MI.getDebugVariable(); |
538 | NumInserted++; |
539 | |
540 | const DIExpression *DIExpr = Expr; |
541 | SmallVector<MachineOperand, 8> MOs; |
542 | for (unsigned I = 0, E = Locs.size(); I < E; ++I) { |
543 | MachineLocKind LocKind = Locs[I].Kind; |
544 | MachineLocValue Loc = Locs[I].Value; |
545 | const MachineOperand &Orig = MI.getDebugOperand(OrigLocMap[I]); |
546 | switch (LocKind) { |
547 | case MachineLocKind::RegisterKind: |
548 | // An entry value is a register location -- but with an updated |
549 | // expression. The register location of such DBG_VALUE is always the |
550 | // one from the entry DBG_VALUE, it does not matter if the entry value |
551 | // was copied in to another register due to some optimizations. |
552 | // Non-entry value register locations are like the source |
553 | // DBG_VALUE, but with the register number from this VarLoc. |
554 | MOs.push_back(MachineOperand::CreateReg( |
555 | EVKind == EntryValueLocKind::EntryValueKind ? Orig.getReg() |
556 | : Register(Loc.RegNo), |
557 | false)); |
558 | MOs.back().setIsDebug(); |
559 | break; |
560 | case MachineLocKind::SpillLocKind: { |
561 | // Spills are indirect DBG_VALUEs, with a base register and offset. |
562 | // Use the original DBG_VALUEs expression to build the spilt location |
563 | // on top of. FIXME: spill locations created before this pass runs |
564 | // are not recognized, and not handled here. |
565 | unsigned Base = Loc.SpillLocation.SpillBase; |
566 | auto *TRI = MF.getSubtarget().getRegisterInfo(); |
567 | if (MI.isNonListDebugValue()) { |
568 | DIExpr = |
569 | TRI->prependOffsetExpression(DIExpr, DIExpression::ApplyOffset, |
570 | Loc.SpillLocation.SpillOffset); |
571 | Indirect = true; |
572 | } else { |
573 | SmallVector<uint64_t, 4> Ops; |
574 | TRI->getOffsetOpcodes(Loc.SpillLocation.SpillOffset, Ops); |
575 | Ops.push_back(dwarf::DW_OP_deref); |
576 | DIExpr = DIExpression::appendOpsToArg(DIExpr, Ops, I); |
577 | } |
578 | MOs.push_back(MachineOperand::CreateReg(Base, false)); |
579 | MOs.back().setIsDebug(); |
580 | break; |
581 | } |
582 | case MachineLocKind::ImmediateKind: { |
583 | MOs.push_back(Orig); |
584 | break; |
585 | } |
586 | case MachineLocKind::InvalidKind: |
587 | llvm_unreachable("Tried to produce DBG_VALUE for invalid VarLoc")__builtin_unreachable(); |
588 | } |
589 | } |
590 | return BuildMI(MF, DbgLoc, IID, Indirect, MOs, Var, DIExpr); |
591 | } |
592 | |
593 | /// Is the Loc field a constant or constant object? |
594 | bool isConstant(MachineLocKind Kind) const { |
595 | return Kind == MachineLocKind::ImmediateKind; |
596 | } |
597 | |
598 | /// Check if the Loc field is an entry backup location. |
599 | bool isEntryBackupLoc() const { |
600 | return EVKind == EntryValueLocKind::EntryValueBackupKind || |
601 | EVKind == EntryValueLocKind::EntryValueCopyBackupKind; |
602 | } |
603 | |
604 | /// If this variable is described by register \p Reg holding the entry |
605 | /// value, return true. |
606 | bool isEntryValueBackupReg(Register Reg) const { |
607 | return EVKind == EntryValueLocKind::EntryValueBackupKind && usesReg(Reg); |
608 | } |
609 | |
610 | /// If this variable is described by register \p Reg holding a copy of the |
611 | /// entry value, return true. |
612 | bool isEntryValueCopyBackupReg(Register Reg) const { |
613 | return EVKind == EntryValueLocKind::EntryValueCopyBackupKind && |
614 | usesReg(Reg); |
615 | } |
616 | |
617 | /// If this variable is described in whole or part by \p Reg, return true. |
618 | bool usesReg(Register Reg) const { |
619 | MachineLoc RegML; |
620 | RegML.Kind = MachineLocKind::RegisterKind; |
621 | RegML.Value.RegNo = Reg; |
622 | return is_contained(Locs, RegML); |
623 | } |
624 | |
625 | /// If this variable is described in whole or part by \p Reg, return true. |
626 | unsigned getRegIdx(Register Reg) const { |
627 | for (unsigned Idx = 0; Idx < Locs.size(); ++Idx) |
628 | if (Locs[Idx].Kind == MachineLocKind::RegisterKind && |
629 | Locs[Idx].Value.RegNo == Reg) |
630 | return Idx; |
631 | llvm_unreachable("Could not find given Reg in Locs")__builtin_unreachable(); |
632 | } |
633 | |
634 | /// If this variable is described in whole or part by 1 or more registers, |
635 | /// add each of them to \p Regs and return true. |
636 | bool getDescribingRegs(SmallVectorImpl<uint32_t> &Regs) const { |
637 | bool AnyRegs = false; |
638 | for (auto Loc : Locs) |
639 | if (Loc.Kind == MachineLocKind::RegisterKind) { |
640 | Regs.push_back(Loc.Value.RegNo); |
641 | AnyRegs = true; |
642 | } |
643 | return AnyRegs; |
644 | } |
645 | |
646 | bool containsSpillLocs() const { |
647 | return any_of(Locs, [](VarLoc::MachineLoc ML) { |
648 | return ML.Kind == VarLoc::MachineLocKind::SpillLocKind; |
649 | }); |
650 | } |
651 | |
652 | /// If this variable is described in whole or part by \p SpillLocation, |
653 | /// return true. |
654 | bool usesSpillLoc(SpillLoc SpillLocation) const { |
655 | MachineLoc SpillML; |
656 | SpillML.Kind = MachineLocKind::SpillLocKind; |
657 | SpillML.Value.SpillLocation = SpillLocation; |
658 | return is_contained(Locs, SpillML); |
659 | } |
660 | |
661 | /// If this variable is described in whole or part by \p SpillLocation, |
662 | /// return the index . |
663 | unsigned getSpillLocIdx(SpillLoc SpillLocation) const { |
664 | for (unsigned Idx = 0; Idx < Locs.size(); ++Idx) |
665 | if (Locs[Idx].Kind == MachineLocKind::SpillLocKind && |
666 | Locs[Idx].Value.SpillLocation == SpillLocation) |
667 | return Idx; |
668 | llvm_unreachable("Could not find given SpillLoc in Locs")__builtin_unreachable(); |
669 | } |
670 | |
671 | /// Determine whether the lexical scope of this value's debug location |
672 | /// dominates MBB. |
673 | bool dominates(LexicalScopes &LS, MachineBasicBlock &MBB) const { |
674 | return LS.dominates(MI.getDebugLoc().get(), &MBB); |
675 | } |
676 | |
677 | #if !defined(NDEBUG1) || defined(LLVM_ENABLE_DUMP) |
678 | // TRI can be null. |
679 | void dump(const TargetRegisterInfo *TRI, raw_ostream &Out = dbgs()) const { |
680 | Out << "VarLoc("; |
681 | for (const MachineLoc &MLoc : Locs) { |
682 | if (Locs.begin() != &MLoc) |
683 | Out << ", "; |
684 | switch (MLoc.Kind) { |
685 | case MachineLocKind::RegisterKind: |
686 | Out << printReg(MLoc.Value.RegNo, TRI); |
687 | break; |
688 | case MachineLocKind::SpillLocKind: |
689 | Out << printReg(MLoc.Value.SpillLocation.SpillBase, TRI); |
690 | Out << "[" << MLoc.Value.SpillLocation.SpillOffset.getFixed() << " + " |
691 | << MLoc.Value.SpillLocation.SpillOffset.getScalable() |
692 | << "x vscale" |
693 | << "]"; |
694 | break; |
695 | case MachineLocKind::ImmediateKind: |
696 | Out << MLoc.Value.Immediate; |
697 | break; |
698 | case MachineLocKind::InvalidKind: |
699 | llvm_unreachable("Invalid VarLoc in dump method")__builtin_unreachable(); |
700 | } |
701 | } |
702 | |
703 | Out << ", \"" << Var.getVariable()->getName() << "\", " << *Expr << ", "; |
704 | if (Var.getInlinedAt()) |
705 | Out << "!" << Var.getInlinedAt()->getMetadataID() << ")\n"; |
706 | else |
707 | Out << "(null))"; |
708 | |
709 | if (isEntryBackupLoc()) |
710 | Out << " (backup loc)\n"; |
711 | else |
712 | Out << "\n"; |
713 | } |
714 | #endif |
715 | |
716 | bool operator==(const VarLoc &Other) const { |
717 | return std::tie(EVKind, Var, Expr, Locs) == |
718 | std::tie(Other.EVKind, Other.Var, Other.Expr, Other.Locs); |
719 | } |
720 | |
721 | /// This operator guarantees that VarLocs are sorted by Variable first. |
722 | bool operator<(const VarLoc &Other) const { |
723 | return std::tie(Var, EVKind, Locs, Expr) < |
724 | std::tie(Other.Var, Other.EVKind, Other.Locs, Other.Expr); |
725 | } |
726 | }; |
727 | |
728 | #ifndef NDEBUG1 |
729 | using VarVec = SmallVector<VarLoc, 32>; |
730 | #endif |
731 | |
732 | /// VarLocMap is used for two things: |
733 | /// 1) Assigning LocIndices to a VarLoc. The LocIndices can be used to |
734 | /// virtually insert a VarLoc into a VarLocSet. |
735 | /// 2) Given a LocIndex, look up the unique associated VarLoc. |
736 | class VarLocMap { |
737 | /// Map a VarLoc to an index within the vector reserved for its location |
738 | /// within Loc2Vars. |
739 | std::map<VarLoc, LocIndices> Var2Indices; |
740 | |
741 | /// Map a location to a vector which holds VarLocs which live in that |
742 | /// location. |
743 | SmallDenseMap<LocIndex::u32_location_t, std::vector<VarLoc>> Loc2Vars; |
744 | |
745 | public: |
746 | /// Retrieve LocIndices for \p VL. |
747 | LocIndices insert(const VarLoc &VL) { |
748 | LocIndices &Indices = Var2Indices[VL]; |
749 | // If Indices is not empty, VL is already in the map. |
750 | if (!Indices.empty()) |
751 | return Indices; |
752 | SmallVector<LocIndex::u32_location_t, 4> Locations; |
753 | // LocIndices are determined by EVKind and MLs; each Register has a |
754 | // unique location, while all SpillLocs use a single bucket, and any EV |
755 | // VarLocs use only the Backup bucket or none at all (except the |
756 | // compulsory entry at the universal location index). LocIndices will |
757 | // always have an index at the universal location index as the last index. |
758 | if (VL.EVKind == VarLoc::EntryValueLocKind::NonEntryValueKind) { |
759 | VL.getDescribingRegs(Locations); |
760 | assert(all_of(Locations,((void)0) |
761 | [](auto RegNo) {((void)0) |
762 | return RegNo < LocIndex::kFirstInvalidRegLocation;((void)0) |
763 | }) &&((void)0) |
764 | "Physreg out of range?")((void)0); |
765 | if (VL.containsSpillLocs()) { |
766 | LocIndex::u32_location_t Loc = LocIndex::kSpillLocation; |
767 | Locations.push_back(Loc); |
768 | } |
769 | } else if (VL.EVKind != VarLoc::EntryValueLocKind::EntryValueKind) { |
770 | LocIndex::u32_location_t Loc = LocIndex::kEntryValueBackupLocation; |
771 | Locations.push_back(Loc); |
772 | } |
773 | Locations.push_back(LocIndex::kUniversalLocation); |
774 | for (LocIndex::u32_location_t Location : Locations) { |
775 | auto &Vars = Loc2Vars[Location]; |
776 | Indices.push_back( |
777 | {Location, static_cast<LocIndex::u32_index_t>(Vars.size())}); |
778 | Vars.push_back(VL); |
779 | } |
780 | return Indices; |
781 | } |
782 | |
783 | LocIndices getAllIndices(const VarLoc &VL) const { |
784 | auto IndIt = Var2Indices.find(VL); |
785 | assert(IndIt != Var2Indices.end() && "VarLoc not tracked")((void)0); |
786 | return IndIt->second; |
787 | } |
788 | |
789 | /// Retrieve the unique VarLoc associated with \p ID. |
790 | const VarLoc &operator[](LocIndex ID) const { |
791 | auto LocIt = Loc2Vars.find(ID.Location); |
792 | assert(LocIt != Loc2Vars.end() && "Location not tracked")((void)0); |
793 | return LocIt->second[ID.Index]; |
794 | } |
795 | }; |
796 | |
797 | using VarLocInMBB = |
798 | SmallDenseMap<const MachineBasicBlock *, std::unique_ptr<VarLocSet>>; |
799 | struct TransferDebugPair { |
800 | MachineInstr *TransferInst; ///< Instruction where this transfer occurs. |
801 | LocIndex LocationID; ///< Location number for the transfer dest. |
802 | }; |
803 | using TransferMap = SmallVector<TransferDebugPair, 4>; |
804 | |
805 | // Types for recording sets of variable fragments that overlap. For a given |
806 | // local variable, we record all other fragments of that variable that could |
807 | // overlap it, to reduce search time. |
808 | using FragmentOfVar = |
809 | std::pair<const DILocalVariable *, DIExpression::FragmentInfo>; |
810 | using OverlapMap = |
811 | DenseMap<FragmentOfVar, SmallVector<DIExpression::FragmentInfo, 1>>; |
812 | |
813 | // Helper while building OverlapMap, a map of all fragments seen for a given |
814 | // DILocalVariable. |
815 | using VarToFragments = |
816 | DenseMap<const DILocalVariable *, SmallSet<FragmentInfo, 4>>; |
817 | |
818 | /// Collects all VarLocs from \p CollectFrom. Each unique VarLoc is added |
819 | /// to \p Collected once, in order of insertion into \p VarLocIDs. |
820 | static void collectAllVarLocs(SmallVectorImpl<VarLoc> &Collected, |
821 | const VarLocSet &CollectFrom, |
822 | const VarLocMap &VarLocIDs); |
823 | |
824 | /// Get the registers which are used by VarLocs of kind RegisterKind tracked |
825 | /// by \p CollectFrom. |
826 | void getUsedRegs(const VarLocSet &CollectFrom, |
827 | SmallVectorImpl<Register> &UsedRegs) const; |
828 | |
829 | /// This holds the working set of currently open ranges. For fast |
830 | /// access, this is done both as a set of VarLocIDs, and a map of |
831 | /// DebugVariable to recent VarLocID. Note that a DBG_VALUE ends all |
832 | /// previous open ranges for the same variable. In addition, we keep |
833 | /// two different maps (Vars/EntryValuesBackupVars), so erase/insert |
834 | /// methods act differently depending on whether a VarLoc is primary |
835 | /// location or backup one. In the case the VarLoc is backup location |
836 | /// we will erase/insert from the EntryValuesBackupVars map, otherwise |
837 | /// we perform the operation on the Vars. |
838 | class OpenRangesSet { |
839 | VarLocSet::Allocator &Alloc; |
840 | VarLocSet VarLocs; |
841 | // Map the DebugVariable to recent primary location ID. |
842 | SmallDenseMap<DebugVariable, LocIndices, 8> Vars; |
843 | // Map the DebugVariable to recent backup location ID. |
844 | SmallDenseMap<DebugVariable, LocIndices, 8> EntryValuesBackupVars; |
845 | OverlapMap &OverlappingFragments; |
846 | |
847 | public: |
848 | OpenRangesSet(VarLocSet::Allocator &Alloc, OverlapMap &_OLapMap) |
849 | : Alloc(Alloc), VarLocs(Alloc), OverlappingFragments(_OLapMap) {} |
850 | |
851 | const VarLocSet &getVarLocs() const { return VarLocs; } |
852 | |
853 | // Fetches all VarLocs in \p VarLocIDs and inserts them into \p Collected. |
854 | // This method is needed to get every VarLoc once, as each VarLoc may have |
855 | // multiple indices in a VarLocMap (corresponding to each applicable |
856 | // location), but all VarLocs appear exactly once at the universal location |
857 | // index. |
858 | void getUniqueVarLocs(SmallVectorImpl<VarLoc> &Collected, |
859 | const VarLocMap &VarLocIDs) const { |
860 | collectAllVarLocs(Collected, VarLocs, VarLocIDs); |
861 | } |
862 | |
863 | /// Terminate all open ranges for VL.Var by removing it from the set. |
864 | void erase(const VarLoc &VL); |
865 | |
866 | /// Terminate all open ranges listed as indices in \c KillSet with |
867 | /// \c Location by removing them from the set. |
868 | void erase(const VarLocsInRange &KillSet, const VarLocMap &VarLocIDs, |
869 | LocIndex::u32_location_t Location); |
870 | |
871 | /// Insert a new range into the set. |
872 | void insert(LocIndices VarLocIDs, const VarLoc &VL); |
873 | |
874 | /// Insert a set of ranges. |
875 | void insertFromLocSet(const VarLocSet &ToLoad, const VarLocMap &Map); |
876 | |
877 | llvm::Optional<LocIndices> getEntryValueBackup(DebugVariable Var); |
878 | |
879 | /// Empty the set. |
880 | void clear() { |
881 | VarLocs.clear(); |
882 | Vars.clear(); |
883 | EntryValuesBackupVars.clear(); |
884 | } |
885 | |
886 | /// Return whether the set is empty or not. |
887 | bool empty() const { |
888 | assert(Vars.empty() == EntryValuesBackupVars.empty() &&((void)0) |
889 | Vars.empty() == VarLocs.empty() &&((void)0) |
890 | "open ranges are inconsistent")((void)0); |
891 | return VarLocs.empty(); |
892 | } |
893 | |
894 | /// Get an empty range of VarLoc IDs. |
895 | auto getEmptyVarLocRange() const { |
896 | return iterator_range<VarLocSet::const_iterator>(getVarLocs().end(), |
897 | getVarLocs().end()); |
898 | } |
899 | |
900 | /// Get all set IDs for VarLocs with MLs of kind RegisterKind in \p Reg. |
901 | auto getRegisterVarLocs(Register Reg) const { |
902 | return LocIndex::indexRangeForLocation(getVarLocs(), Reg); |
903 | } |
904 | |
905 | /// Get all set IDs for VarLocs with MLs of kind SpillLocKind. |
906 | auto getSpillVarLocs() const { |
907 | return LocIndex::indexRangeForLocation(getVarLocs(), |
908 | LocIndex::kSpillLocation); |
909 | } |
910 | |
911 | /// Get all set IDs for VarLocs of EVKind EntryValueBackupKind or |
912 | /// EntryValueCopyBackupKind. |
913 | auto getEntryValueBackupVarLocs() const { |
914 | return LocIndex::indexRangeForLocation( |
915 | getVarLocs(), LocIndex::kEntryValueBackupLocation); |
916 | } |
917 | }; |
918 | |
919 | /// Collect all VarLoc IDs from \p CollectFrom for VarLocs with MLs of kind |
920 | /// RegisterKind which are located in any reg in \p Regs. The IDs for each |
921 | /// VarLoc correspond to entries in the universal location bucket, which every |
922 | /// VarLoc has exactly 1 entry for. Insert collected IDs into \p Collected. |
923 | static void collectIDsForRegs(VarLocsInRange &Collected, |
924 | const DefinedRegsSet &Regs, |
925 | const VarLocSet &CollectFrom, |
926 | const VarLocMap &VarLocIDs); |
927 | |
928 | VarLocSet &getVarLocsInMBB(const MachineBasicBlock *MBB, VarLocInMBB &Locs) { |
929 | std::unique_ptr<VarLocSet> &VLS = Locs[MBB]; |
930 | if (!VLS) |
931 | VLS = std::make_unique<VarLocSet>(Alloc); |
932 | return *VLS.get(); |
933 | } |
934 | |
935 | const VarLocSet &getVarLocsInMBB(const MachineBasicBlock *MBB, |
936 | const VarLocInMBB &Locs) const { |
937 | auto It = Locs.find(MBB); |
938 | assert(It != Locs.end() && "MBB not in map")((void)0); |
939 | return *It->second.get(); |
940 | } |
941 | |
942 | /// Tests whether this instruction is a spill to a stack location. |
943 | bool isSpillInstruction(const MachineInstr &MI, MachineFunction *MF); |
944 | |
945 | /// Decide if @MI is a spill instruction and return true if it is. We use 2 |
946 | /// criteria to make this decision: |
947 | /// - Is this instruction a store to a spill slot? |
948 | /// - Is there a register operand that is both used and killed? |
949 | /// TODO: Store optimization can fold spills into other stores (including |
950 | /// other spills). We do not handle this yet (more than one memory operand). |
951 | bool isLocationSpill(const MachineInstr &MI, MachineFunction *MF, |
952 | Register &Reg); |
953 | |
954 | /// Returns true if the given machine instruction is a debug value which we |
955 | /// can emit entry values for. |
956 | /// |
957 | /// Currently, we generate debug entry values only for parameters that are |
958 | /// unmodified throughout the function and located in a register. |
959 | bool isEntryValueCandidate(const MachineInstr &MI, |
960 | const DefinedRegsSet &Regs) const; |
961 | |
962 | /// If a given instruction is identified as a spill, return the spill location |
963 | /// and set \p Reg to the spilled register. |
964 | Optional<VarLoc::SpillLoc> isRestoreInstruction(const MachineInstr &MI, |
965 | MachineFunction *MF, |
966 | Register &Reg); |
967 | /// Given a spill instruction, extract the register and offset used to |
968 | /// address the spill location in a target independent way. |
969 | VarLoc::SpillLoc extractSpillBaseRegAndOffset(const MachineInstr &MI); |
970 | void insertTransferDebugPair(MachineInstr &MI, OpenRangesSet &OpenRanges, |
971 | TransferMap &Transfers, VarLocMap &VarLocIDs, |
972 | LocIndex OldVarID, TransferKind Kind, |
973 | const VarLoc::MachineLoc &OldLoc, |
974 | Register NewReg = Register()); |
975 | |
976 | void transferDebugValue(const MachineInstr &MI, OpenRangesSet &OpenRanges, |
977 | VarLocMap &VarLocIDs); |
978 | void transferSpillOrRestoreInst(MachineInstr &MI, OpenRangesSet &OpenRanges, |
979 | VarLocMap &VarLocIDs, TransferMap &Transfers); |
980 | bool removeEntryValue(const MachineInstr &MI, OpenRangesSet &OpenRanges, |
981 | VarLocMap &VarLocIDs, const VarLoc &EntryVL); |
982 | void emitEntryValues(MachineInstr &MI, OpenRangesSet &OpenRanges, |
983 | VarLocMap &VarLocIDs, TransferMap &Transfers, |
984 | VarLocsInRange &KillSet); |
985 | void recordEntryValue(const MachineInstr &MI, |
986 | const DefinedRegsSet &DefinedRegs, |
987 | OpenRangesSet &OpenRanges, VarLocMap &VarLocIDs); |
988 | void transferRegisterCopy(MachineInstr &MI, OpenRangesSet &OpenRanges, |
989 | VarLocMap &VarLocIDs, TransferMap &Transfers); |
990 | void transferRegisterDef(MachineInstr &MI, OpenRangesSet &OpenRanges, |
991 | VarLocMap &VarLocIDs, TransferMap &Transfers); |
992 | bool transferTerminator(MachineBasicBlock *MBB, OpenRangesSet &OpenRanges, |
993 | VarLocInMBB &OutLocs, const VarLocMap &VarLocIDs); |
994 | |
995 | void process(MachineInstr &MI, OpenRangesSet &OpenRanges, |
996 | VarLocMap &VarLocIDs, TransferMap &Transfers); |
997 | |
998 | void accumulateFragmentMap(MachineInstr &MI, VarToFragments &SeenFragments, |
999 | OverlapMap &OLapMap); |
1000 | |
1001 | bool join(MachineBasicBlock &MBB, VarLocInMBB &OutLocs, VarLocInMBB &InLocs, |
1002 | const VarLocMap &VarLocIDs, |
1003 | SmallPtrSet<const MachineBasicBlock *, 16> &Visited, |
1004 | SmallPtrSetImpl<const MachineBasicBlock *> &ArtificialBlocks); |
1005 | |
1006 | /// Create DBG_VALUE insts for inlocs that have been propagated but |
1007 | /// had their instruction creation deferred. |
1008 | void flushPendingLocs(VarLocInMBB &PendingInLocs, VarLocMap &VarLocIDs); |
1009 | |
1010 | bool ExtendRanges(MachineFunction &MF, TargetPassConfig *TPC) override; |
1011 | |
1012 | public: |
1013 | /// Default construct and initialize the pass. |
1014 | VarLocBasedLDV(); |
1015 | |
1016 | ~VarLocBasedLDV(); |
1017 | |
1018 | /// Print to ostream with a message. |
1019 | void printVarLocInMBB(const MachineFunction &MF, const VarLocInMBB &V, |
1020 | const VarLocMap &VarLocIDs, const char *msg, |
1021 | raw_ostream &Out) const; |
1022 | }; |
1023 | |
1024 | } // end anonymous namespace |
1025 | |
1026 | //===----------------------------------------------------------------------===// |
1027 | // Implementation |
1028 | //===----------------------------------------------------------------------===// |
1029 | |
1030 | VarLocBasedLDV::VarLocBasedLDV() { } |
1031 | |
1032 | VarLocBasedLDV::~VarLocBasedLDV() { } |
1033 | |
1034 | /// Erase a variable from the set of open ranges, and additionally erase any |
1035 | /// fragments that may overlap it. If the VarLoc is a backup location, erase |
1036 | /// the variable from the EntryValuesBackupVars set, indicating we should stop |
1037 | /// tracking its backup entry location. Otherwise, if the VarLoc is primary |
1038 | /// location, erase the variable from the Vars set. |
1039 | void VarLocBasedLDV::OpenRangesSet::erase(const VarLoc &VL) { |
1040 | // Erasure helper. |
1041 | auto DoErase = [VL, this](DebugVariable VarToErase) { |
1042 | auto *EraseFrom = VL.isEntryBackupLoc() ? &EntryValuesBackupVars : &Vars; |
1043 | auto It = EraseFrom->find(VarToErase); |
1044 | if (It != EraseFrom->end()) { |
1045 | LocIndices IDs = It->second; |
1046 | for (LocIndex ID : IDs) |
1047 | VarLocs.reset(ID.getAsRawInteger()); |
1048 | EraseFrom->erase(It); |
1049 | } |
1050 | }; |
1051 | |
1052 | DebugVariable Var = VL.Var; |
1053 | |
1054 | // Erase the variable/fragment that ends here. |
1055 | DoErase(Var); |
1056 | |
1057 | // Extract the fragment. Interpret an empty fragment as one that covers all |
1058 | // possible bits. |
1059 | FragmentInfo ThisFragment = Var.getFragmentOrDefault(); |
1060 | |
1061 | // There may be fragments that overlap the designated fragment. Look them up |
1062 | // in the pre-computed overlap map, and erase them too. |
1063 | auto MapIt = OverlappingFragments.find({Var.getVariable(), ThisFragment}); |
1064 | if (MapIt != OverlappingFragments.end()) { |
1065 | for (auto Fragment : MapIt->second) { |
1066 | VarLocBasedLDV::OptFragmentInfo FragmentHolder; |
1067 | if (!DebugVariable::isDefaultFragment(Fragment)) |
1068 | FragmentHolder = VarLocBasedLDV::OptFragmentInfo(Fragment); |
1069 | DoErase({Var.getVariable(), FragmentHolder, Var.getInlinedAt()}); |
1070 | } |
1071 | } |
1072 | } |
1073 | |
1074 | void VarLocBasedLDV::OpenRangesSet::erase(const VarLocsInRange &KillSet, |
1075 | const VarLocMap &VarLocIDs, |
1076 | LocIndex::u32_location_t Location) { |
1077 | VarLocSet RemoveSet(Alloc); |
1078 | for (LocIndex::u32_index_t ID : KillSet) { |
1079 | const VarLoc &VL = VarLocIDs[LocIndex(Location, ID)]; |
1080 | auto *EraseFrom = VL.isEntryBackupLoc() ? &EntryValuesBackupVars : &Vars; |
1081 | EraseFrom->erase(VL.Var); |
1082 | LocIndices VLI = VarLocIDs.getAllIndices(VL); |
1083 | for (LocIndex ID : VLI) |
1084 | RemoveSet.set(ID.getAsRawInteger()); |
1085 | } |
1086 | VarLocs.intersectWithComplement(RemoveSet); |
1087 | } |
1088 | |
1089 | void VarLocBasedLDV::OpenRangesSet::insertFromLocSet(const VarLocSet &ToLoad, |
1090 | const VarLocMap &Map) { |
1091 | VarLocsInRange UniqueVarLocIDs; |
1092 | DefinedRegsSet Regs; |
1093 | Regs.insert(LocIndex::kUniversalLocation); |
1094 | collectIDsForRegs(UniqueVarLocIDs, Regs, ToLoad, Map); |
1095 | for (uint64_t ID : UniqueVarLocIDs) { |
1096 | LocIndex Idx = LocIndex::fromRawInteger(ID); |
1097 | const VarLoc &VarL = Map[Idx]; |
1098 | const LocIndices Indices = Map.getAllIndices(VarL); |
1099 | insert(Indices, VarL); |
1100 | } |
1101 | } |
1102 | |
1103 | void VarLocBasedLDV::OpenRangesSet::insert(LocIndices VarLocIDs, |
1104 | const VarLoc &VL) { |
1105 | auto *InsertInto = VL.isEntryBackupLoc() ? &EntryValuesBackupVars : &Vars; |
1106 | for (LocIndex ID : VarLocIDs) |
1107 | VarLocs.set(ID.getAsRawInteger()); |
1108 | InsertInto->insert({VL.Var, VarLocIDs}); |
1109 | } |
1110 | |
1111 | /// Return the Loc ID of an entry value backup location, if it exists for the |
1112 | /// variable. |
1113 | llvm::Optional<LocIndices> |
1114 | VarLocBasedLDV::OpenRangesSet::getEntryValueBackup(DebugVariable Var) { |
1115 | auto It = EntryValuesBackupVars.find(Var); |
1116 | if (It != EntryValuesBackupVars.end()) |
1117 | return It->second; |
1118 | |
1119 | return llvm::None; |
1120 | } |
1121 | |
1122 | void VarLocBasedLDV::collectIDsForRegs(VarLocsInRange &Collected, |
1123 | const DefinedRegsSet &Regs, |
1124 | const VarLocSet &CollectFrom, |
1125 | const VarLocMap &VarLocIDs) { |
1126 | assert(!Regs.empty() && "Nothing to collect")((void)0); |
1127 | SmallVector<Register, 32> SortedRegs; |
1128 | append_range(SortedRegs, Regs); |
1129 | array_pod_sort(SortedRegs.begin(), SortedRegs.end()); |
1130 | auto It = CollectFrom.find(LocIndex::rawIndexForReg(SortedRegs.front())); |
1131 | auto End = CollectFrom.end(); |
1132 | for (Register Reg : SortedRegs) { |
1133 | // The half-open interval [FirstIndexForReg, FirstInvalidIndex) contains |
1134 | // all possible VarLoc IDs for VarLocs with MLs of kind RegisterKind which |
1135 | // live in Reg. |
1136 | uint64_t FirstIndexForReg = LocIndex::rawIndexForReg(Reg); |
1137 | uint64_t FirstInvalidIndex = LocIndex::rawIndexForReg(Reg + 1); |
1138 | It.advanceToLowerBound(FirstIndexForReg); |
1139 | |
1140 | // Iterate through that half-open interval and collect all the set IDs. |
1141 | for (; It != End && *It < FirstInvalidIndex; ++It) { |
1142 | LocIndex ItIdx = LocIndex::fromRawInteger(*It); |
1143 | const VarLoc &VL = VarLocIDs[ItIdx]; |
1144 | LocIndices LI = VarLocIDs.getAllIndices(VL); |
1145 | // For now, the back index is always the universal location index. |
1146 | assert(LI.back().Location == LocIndex::kUniversalLocation &&((void)0) |
1147 | "Unexpected order of LocIndices for VarLoc; was it inserted into "((void)0) |
1148 | "the VarLocMap correctly?")((void)0); |
1149 | Collected.insert(LI.back().Index); |
1150 | } |
1151 | |
1152 | if (It == End) |
1153 | return; |
1154 | } |
1155 | } |
1156 | |
1157 | void VarLocBasedLDV::getUsedRegs(const VarLocSet &CollectFrom, |
1158 | SmallVectorImpl<Register> &UsedRegs) const { |
1159 | // All register-based VarLocs are assigned indices greater than or equal to |
1160 | // FirstRegIndex. |
1161 | uint64_t FirstRegIndex = |
1162 | LocIndex::rawIndexForReg(LocIndex::kFirstRegLocation); |
1163 | uint64_t FirstInvalidIndex = |
1164 | LocIndex::rawIndexForReg(LocIndex::kFirstInvalidRegLocation); |
1165 | for (auto It = CollectFrom.find(FirstRegIndex), |
1166 | End = CollectFrom.find(FirstInvalidIndex); |
1167 | It != End;) { |
1168 | // We found a VarLoc ID for a VarLoc that lives in a register. Figure out |
1169 | // which register and add it to UsedRegs. |
1170 | uint32_t FoundReg = LocIndex::fromRawInteger(*It).Location; |
1171 | assert((UsedRegs.empty() || FoundReg != UsedRegs.back()) &&((void)0) |
1172 | "Duplicate used reg")((void)0); |
1173 | UsedRegs.push_back(FoundReg); |
1174 | |
1175 | // Skip to the next /set/ register. Note that this finds a lower bound, so |
1176 | // even if there aren't any VarLocs living in `FoundReg+1`, we're still |
1177 | // guaranteed to move on to the next register (or to end()). |
1178 | uint64_t NextRegIndex = LocIndex::rawIndexForReg(FoundReg + 1); |
1179 | It.advanceToLowerBound(NextRegIndex); |
1180 | } |
1181 | } |
1182 | |
1183 | //===----------------------------------------------------------------------===// |
1184 | // Debug Range Extension Implementation |
1185 | //===----------------------------------------------------------------------===// |
1186 | |
1187 | #ifndef NDEBUG1 |
1188 | void VarLocBasedLDV::printVarLocInMBB(const MachineFunction &MF, |
1189 | const VarLocInMBB &V, |
1190 | const VarLocMap &VarLocIDs, |
1191 | const char *msg, |
1192 | raw_ostream &Out) const { |
1193 | Out << '\n' << msg << '\n'; |
1194 | for (const MachineBasicBlock &BB : MF) { |
1195 | if (!V.count(&BB)) |
1196 | continue; |
1197 | const VarLocSet &L = getVarLocsInMBB(&BB, V); |
1198 | if (L.empty()) |
1199 | continue; |
1200 | SmallVector<VarLoc, 32> VarLocs; |
1201 | collectAllVarLocs(VarLocs, L, VarLocIDs); |
1202 | Out << "MBB: " << BB.getNumber() << ":\n"; |
1203 | for (const VarLoc &VL : VarLocs) { |
1204 | Out << " Var: " << VL.Var.getVariable()->getName(); |
1205 | Out << " MI: "; |
1206 | VL.dump(TRI, Out); |
1207 | } |
1208 | } |
1209 | Out << "\n"; |
1210 | } |
1211 | #endif |
1212 | |
1213 | VarLocBasedLDV::VarLoc::SpillLoc |
1214 | VarLocBasedLDV::extractSpillBaseRegAndOffset(const MachineInstr &MI) { |
1215 | assert(MI.hasOneMemOperand() &&((void)0) |
1216 | "Spill instruction does not have exactly one memory operand?")((void)0); |
1217 | auto MMOI = MI.memoperands_begin(); |
1218 | const PseudoSourceValue *PVal = (*MMOI)->getPseudoValue(); |
1219 | assert(PVal->kind() == PseudoSourceValue::FixedStack &&((void)0) |
1220 | "Inconsistent memory operand in spill instruction")((void)0); |
1221 | int FI = cast<FixedStackPseudoSourceValue>(PVal)->getFrameIndex(); |
1222 | const MachineBasicBlock *MBB = MI.getParent(); |
1223 | Register Reg; |
1224 | StackOffset Offset = TFI->getFrameIndexReference(*MBB->getParent(), FI, Reg); |
1225 | return {Reg, Offset}; |
1226 | } |
1227 | |
1228 | /// Try to salvage the debug entry value if we encounter a new debug value |
1229 | /// describing the same parameter, otherwise stop tracking the value. Return |
1230 | /// true if we should stop tracking the entry value, otherwise return false. |
1231 | bool VarLocBasedLDV::removeEntryValue(const MachineInstr &MI, |
1232 | OpenRangesSet &OpenRanges, |
1233 | VarLocMap &VarLocIDs, |
1234 | const VarLoc &EntryVL) { |
1235 | // Skip the DBG_VALUE which is the debug entry value itself. |
1236 | if (MI.isIdenticalTo(EntryVL.MI)) |
1237 | return false; |
1238 | |
1239 | // If the parameter's location is not register location, we can not track |
1240 | // the entry value any more. In addition, if the debug expression from the |
1241 | // DBG_VALUE is not empty, we can assume the parameter's value has changed |
1242 | // indicating that we should stop tracking its entry value as well. |
1243 | if (!MI.getDebugOperand(0).isReg() || |
1244 | MI.getDebugExpression()->getNumElements() != 0) |
1245 | return true; |
1246 | |
1247 | // If the DBG_VALUE comes from a copy instruction that copies the entry value, |
1248 | // it means the parameter's value has not changed and we should be able to use |
1249 | // its entry value. |
1250 | Register Reg = MI.getDebugOperand(0).getReg(); |
1251 | auto I = std::next(MI.getReverseIterator()); |
1252 | const MachineOperand *SrcRegOp, *DestRegOp; |
1253 | if (I != MI.getParent()->rend()) { |
1254 | |
1255 | // TODO: Try to keep tracking of an entry value if we encounter a propagated |
1256 | // DBG_VALUE describing the copy of the entry value. (Propagated entry value |
1257 | // does not indicate the parameter modification.) |
1258 | auto DestSrc = TII->isCopyInstr(*I); |
1259 | if (!DestSrc) |
1260 | return true; |
1261 | |
1262 | SrcRegOp = DestSrc->Source; |
1263 | DestRegOp = DestSrc->Destination; |
1264 | if (Reg != DestRegOp->getReg()) |
1265 | return true; |
1266 | |
1267 | for (uint64_t ID : OpenRanges.getEntryValueBackupVarLocs()) { |
1268 | const VarLoc &VL = VarLocIDs[LocIndex::fromRawInteger(ID)]; |
1269 | if (VL.isEntryValueCopyBackupReg(Reg) && |
1270 | // Entry Values should not be variadic. |
1271 | VL.MI.getDebugOperand(0).getReg() == SrcRegOp->getReg()) |
1272 | return false; |
1273 | } |
1274 | } |
1275 | |
1276 | return true; |
1277 | } |
1278 | |
1279 | /// End all previous ranges related to @MI and start a new range from @MI |
1280 | /// if it is a DBG_VALUE instr. |
1281 | void VarLocBasedLDV::transferDebugValue(const MachineInstr &MI, |
1282 | OpenRangesSet &OpenRanges, |
1283 | VarLocMap &VarLocIDs) { |
1284 | if (!MI.isDebugValue()) |
1285 | return; |
1286 | const DILocalVariable *Var = MI.getDebugVariable(); |
1287 | const DIExpression *Expr = MI.getDebugExpression(); |
1288 | const DILocation *DebugLoc = MI.getDebugLoc(); |
1289 | const DILocation *InlinedAt = DebugLoc->getInlinedAt(); |
1290 | assert(Var->isValidLocationForIntrinsic(DebugLoc) &&((void)0) |
1291 | "Expected inlined-at fields to agree")((void)0); |
1292 | |
1293 | DebugVariable V(Var, Expr, InlinedAt); |
1294 | |
1295 | // Check if this DBG_VALUE indicates a parameter's value changing. |
1296 | // If that is the case, we should stop tracking its entry value. |
1297 | auto EntryValBackupID = OpenRanges.getEntryValueBackup(V); |
1298 | if (Var->isParameter() && EntryValBackupID) { |
1299 | const VarLoc &EntryVL = VarLocIDs[EntryValBackupID->back()]; |
1300 | if (removeEntryValue(MI, OpenRanges, VarLocIDs, EntryVL)) { |
1301 | LLVM_DEBUG(dbgs() << "Deleting a DBG entry value because of: ";do { } while (false) |
1302 | MI.print(dbgs(), /*IsStandalone*/ false,do { } while (false) |
1303 | /*SkipOpers*/ false, /*SkipDebugLoc*/ false,do { } while (false) |
1304 | /*AddNewLine*/ true, TII))do { } while (false); |
1305 | OpenRanges.erase(EntryVL); |
1306 | } |
1307 | } |
1308 | |
1309 | if (all_of(MI.debug_operands(), [](const MachineOperand &MO) { |
1310 | return (MO.isReg() && MO.getReg()) || MO.isImm() || MO.isFPImm() || |
1311 | MO.isCImm(); |
1312 | })) { |
1313 | // Use normal VarLoc constructor for registers and immediates. |
1314 | VarLoc VL(MI, LS); |
1315 | // End all previous ranges of VL.Var. |
1316 | OpenRanges.erase(VL); |
1317 | |
1318 | LocIndices IDs = VarLocIDs.insert(VL); |
1319 | // Add the VarLoc to OpenRanges from this DBG_VALUE. |
1320 | OpenRanges.insert(IDs, VL); |
1321 | } else if (MI.memoperands().size() > 0) { |
1322 | llvm_unreachable("DBG_VALUE with mem operand encountered after regalloc?")__builtin_unreachable(); |
1323 | } else { |
1324 | // This must be an undefined location. If it has an open range, erase it. |
1325 | assert(MI.isUndefDebugValue() &&((void)0) |
1326 | "Unexpected non-undef DBG_VALUE encountered")((void)0); |
1327 | VarLoc VL(MI, LS); |
1328 | OpenRanges.erase(VL); |
1329 | } |
1330 | } |
1331 | |
1332 | // This should be removed later, doesn't fit the new design. |
1333 | void VarLocBasedLDV::collectAllVarLocs(SmallVectorImpl<VarLoc> &Collected, |
1334 | const VarLocSet &CollectFrom, |
1335 | const VarLocMap &VarLocIDs) { |
1336 | // The half-open interval [FirstIndexForReg, FirstInvalidIndex) contains all |
1337 | // possible VarLoc IDs for VarLocs with MLs of kind RegisterKind which live |
1338 | // in Reg. |
1339 | uint64_t FirstIndex = LocIndex::rawIndexForReg(LocIndex::kUniversalLocation); |
1340 | uint64_t FirstInvalidIndex = |
1341 | LocIndex::rawIndexForReg(LocIndex::kUniversalLocation + 1); |
1342 | // Iterate through that half-open interval and collect all the set IDs. |
1343 | for (auto It = CollectFrom.find(FirstIndex), End = CollectFrom.end(); |
1344 | It != End && *It < FirstInvalidIndex; ++It) { |
1345 | LocIndex RegIdx = LocIndex::fromRawInteger(*It); |
1346 | Collected.push_back(VarLocIDs[RegIdx]); |
1347 | } |
1348 | } |
1349 | |
1350 | /// Turn the entry value backup locations into primary locations. |
1351 | void VarLocBasedLDV::emitEntryValues(MachineInstr &MI, |
1352 | OpenRangesSet &OpenRanges, |
1353 | VarLocMap &VarLocIDs, |
1354 | TransferMap &Transfers, |
1355 | VarLocsInRange &KillSet) { |
1356 | // Do not insert entry value locations after a terminator. |
1357 | if (MI.isTerminator()) |
1358 | return; |
1359 | |
1360 | for (uint32_t ID : KillSet) { |
1361 | // The KillSet IDs are indices for the universal location bucket. |
1362 | LocIndex Idx = LocIndex(LocIndex::kUniversalLocation, ID); |
1363 | const VarLoc &VL = VarLocIDs[Idx]; |
1364 | if (!VL.Var.getVariable()->isParameter()) |
1365 | continue; |
1366 | |
1367 | auto DebugVar = VL.Var; |
1368 | Optional<LocIndices> EntryValBackupIDs = |
1369 | OpenRanges.getEntryValueBackup(DebugVar); |
1370 | |
1371 | // If the parameter has the entry value backup, it means we should |
1372 | // be able to use its entry value. |
1373 | if (!EntryValBackupIDs) |
1374 | continue; |
1375 | |
1376 | const VarLoc &EntryVL = VarLocIDs[EntryValBackupIDs->back()]; |
1377 | VarLoc EntryLoc = VarLoc::CreateEntryLoc(EntryVL.MI, LS, EntryVL.Expr, |
1378 | EntryVL.Locs[0].Value.RegNo); |
1379 | LocIndices EntryValueIDs = VarLocIDs.insert(EntryLoc); |
1380 | Transfers.push_back({&MI, EntryValueIDs.back()}); |
1381 | OpenRanges.insert(EntryValueIDs, EntryLoc); |
1382 | } |
1383 | } |
1384 | |
1385 | /// Create new TransferDebugPair and insert it in \p Transfers. The VarLoc |
1386 | /// with \p OldVarID should be deleted form \p OpenRanges and replaced with |
1387 | /// new VarLoc. If \p NewReg is different than default zero value then the |
1388 | /// new location will be register location created by the copy like instruction, |
1389 | /// otherwise it is variable's location on the stack. |
1390 | void VarLocBasedLDV::insertTransferDebugPair( |
1391 | MachineInstr &MI, OpenRangesSet &OpenRanges, TransferMap &Transfers, |
1392 | VarLocMap &VarLocIDs, LocIndex OldVarID, TransferKind Kind, |
1393 | const VarLoc::MachineLoc &OldLoc, Register NewReg) { |
1394 | const VarLoc &OldVarLoc = VarLocIDs[OldVarID]; |
1395 | |
1396 | auto ProcessVarLoc = [&MI, &OpenRanges, &Transfers, &VarLocIDs](VarLoc &VL) { |
1397 | LocIndices LocIds = VarLocIDs.insert(VL); |
1398 | |
1399 | // Close this variable's previous location range. |
1400 | OpenRanges.erase(VL); |
1401 | |
1402 | // Record the new location as an open range, and a postponed transfer |
1403 | // inserting a DBG_VALUE for this location. |
1404 | OpenRanges.insert(LocIds, VL); |
1405 | assert(!MI.isTerminator() && "Cannot insert DBG_VALUE after terminator")((void)0); |
1406 | TransferDebugPair MIP = {&MI, LocIds.back()}; |
1407 | Transfers.push_back(MIP); |
1408 | }; |
1409 | |
1410 | // End all previous ranges of VL.Var. |
1411 | OpenRanges.erase(VarLocIDs[OldVarID]); |
1412 | switch (Kind) { |
1413 | case TransferKind::TransferCopy: { |
1414 | assert(NewReg &&((void)0) |
1415 | "No register supplied when handling a copy of a debug value")((void)0); |
1416 | // Create a DBG_VALUE instruction to describe the Var in its new |
1417 | // register location. |
1418 | VarLoc VL = VarLoc::CreateCopyLoc(OldVarLoc, OldLoc, NewReg); |
1419 | ProcessVarLoc(VL); |
1420 | LLVM_DEBUG({do { } while (false) |
1421 | dbgs() << "Creating VarLoc for register copy:";do { } while (false) |
1422 | VL.dump(TRI);do { } while (false) |
1423 | })do { } while (false); |
1424 | return; |
1425 | } |
1426 | case TransferKind::TransferSpill: { |
1427 | // Create a DBG_VALUE instruction to describe the Var in its spilled |
1428 | // location. |
1429 | VarLoc::SpillLoc SpillLocation = extractSpillBaseRegAndOffset(MI); |
1430 | VarLoc VL = VarLoc::CreateSpillLoc( |
1431 | OldVarLoc, OldLoc, SpillLocation.SpillBase, SpillLocation.SpillOffset); |
1432 | ProcessVarLoc(VL); |
1433 | LLVM_DEBUG({do { } while (false) |
1434 | dbgs() << "Creating VarLoc for spill:";do { } while (false) |
1435 | VL.dump(TRI);do { } while (false) |
1436 | })do { } while (false); |
1437 | return; |
1438 | } |
1439 | case TransferKind::TransferRestore: { |
1440 | assert(NewReg &&((void)0) |
1441 | "No register supplied when handling a restore of a debug value")((void)0); |
1442 | // DebugInstr refers to the pre-spill location, therefore we can reuse |
1443 | // its expression. |
1444 | VarLoc VL = VarLoc::CreateCopyLoc(OldVarLoc, OldLoc, NewReg); |
1445 | ProcessVarLoc(VL); |
1446 | LLVM_DEBUG({do { } while (false) |
1447 | dbgs() << "Creating VarLoc for restore:";do { } while (false) |
1448 | VL.dump(TRI);do { } while (false) |
1449 | })do { } while (false); |
1450 | return; |
1451 | } |
1452 | } |
1453 | llvm_unreachable("Invalid transfer kind")__builtin_unreachable(); |
1454 | } |
1455 | |
1456 | /// A definition of a register may mark the end of a range. |
1457 | void VarLocBasedLDV::transferRegisterDef( |
1458 | MachineInstr &MI, OpenRangesSet &OpenRanges, VarLocMap &VarLocIDs, |
1459 | TransferMap &Transfers) { |
1460 | |
1461 | // Meta Instructions do not affect the debug liveness of any register they |
1462 | // define. |
1463 | if (MI.isMetaInstruction()) |
1464 | return; |
1465 | |
1466 | MachineFunction *MF = MI.getMF(); |
1467 | const TargetLowering *TLI = MF->getSubtarget().getTargetLowering(); |
1468 | Register SP = TLI->getStackPointerRegisterToSaveRestore(); |
1469 | |
1470 | // Find the regs killed by MI, and find regmasks of preserved regs. |
1471 | DefinedRegsSet DeadRegs; |
1472 | SmallVector<const uint32_t *, 4> RegMasks; |
1473 | for (const MachineOperand &MO : MI.operands()) { |
1474 | // Determine whether the operand is a register def. |
1475 | if (MO.isReg() && MO.isDef() && MO.getReg() && |
1476 | Register::isPhysicalRegister(MO.getReg()) && |
1477 | !(MI.isCall() && MO.getReg() == SP)) { |
1478 | // Remove ranges of all aliased registers. |
1479 | for (MCRegAliasIterator RAI(MO.getReg(), TRI, true); RAI.isValid(); ++RAI) |
1480 | // FIXME: Can we break out of this loop early if no insertion occurs? |
1481 | DeadRegs.insert(*RAI); |
1482 | } else if (MO.isRegMask()) { |
1483 | RegMasks.push_back(MO.getRegMask()); |
1484 | } |
1485 | } |
1486 | |
1487 | // Erase VarLocs which reside in one of the dead registers. For performance |
1488 | // reasons, it's critical to not iterate over the full set of open VarLocs. |
1489 | // Iterate over the set of dying/used regs instead. |
1490 | if (!RegMasks.empty()) { |
1491 | SmallVector<Register, 32> UsedRegs; |
1492 | getUsedRegs(OpenRanges.getVarLocs(), UsedRegs); |
1493 | for (Register Reg : UsedRegs) { |
1494 | // Remove ranges of all clobbered registers. Register masks don't usually |
1495 | // list SP as preserved. Assume that call instructions never clobber SP, |
1496 | // because some backends (e.g., AArch64) never list SP in the regmask. |
1497 | // While the debug info may be off for an instruction or two around |
1498 | // callee-cleanup calls, transferring the DEBUG_VALUE across the call is |
1499 | // still a better user experience. |
1500 | if (Reg == SP) |
1501 | continue; |
1502 | bool AnyRegMaskKillsReg = |
1503 | any_of(RegMasks, [Reg](const uint32_t *RegMask) { |
1504 | return MachineOperand::clobbersPhysReg(RegMask, Reg); |
1505 | }); |
1506 | if (AnyRegMaskKillsReg) |
1507 | DeadRegs.insert(Reg); |
1508 | } |
1509 | } |
1510 | |
1511 | if (DeadRegs.empty()) |
1512 | return; |
1513 | |
1514 | VarLocsInRange KillSet; |
1515 | collectIDsForRegs(KillSet, DeadRegs, OpenRanges.getVarLocs(), VarLocIDs); |
1516 | OpenRanges.erase(KillSet, VarLocIDs, LocIndex::kUniversalLocation); |
1517 | |
1518 | if (TPC) { |
1519 | auto &TM = TPC->getTM<TargetMachine>(); |
1520 | if (TM.Options.ShouldEmitDebugEntryValues()) |
1521 | emitEntryValues(MI, OpenRanges, VarLocIDs, Transfers, KillSet); |
1522 | } |
1523 | } |
1524 | |
1525 | bool VarLocBasedLDV::isSpillInstruction(const MachineInstr &MI, |
1526 | MachineFunction *MF) { |
1527 | // TODO: Handle multiple stores folded into one. |
1528 | if (!MI.hasOneMemOperand()) |
1529 | return false; |
1530 | |
1531 | if (!MI.getSpillSize(TII) && !MI.getFoldedSpillSize(TII)) |
1532 | return false; // This is not a spill instruction, since no valid size was |
1533 | // returned from either function. |
1534 | |
1535 | return true; |
1536 | } |
1537 | |
1538 | bool VarLocBasedLDV::isLocationSpill(const MachineInstr &MI, |
1539 | MachineFunction *MF, Register &Reg) { |
1540 | if (!isSpillInstruction(MI, MF)) |
1541 | return false; |
1542 | |
1543 | auto isKilledReg = [&](const MachineOperand MO, Register &Reg) { |
1544 | if (!MO.isReg() || !MO.isUse()) { |
1545 | Reg = 0; |
1546 | return false; |
1547 | } |
1548 | Reg = MO.getReg(); |
1549 | return MO.isKill(); |
1550 | }; |
1551 | |
1552 | for (const MachineOperand &MO : MI.operands()) { |
1553 | // In a spill instruction generated by the InlineSpiller the spilled |
1554 | // register has its kill flag set. |
1555 | if (isKilledReg(MO, Reg)) |
1556 | return true; |
1557 | if (Reg != 0) { |
1558 | // Check whether next instruction kills the spilled register. |
1559 | // FIXME: Current solution does not cover search for killed register in |
1560 | // bundles and instructions further down the chain. |
1561 | auto NextI = std::next(MI.getIterator()); |
1562 | // Skip next instruction that points to basic block end iterator. |
1563 | if (MI.getParent()->end() == NextI) |
1564 | continue; |
1565 | Register RegNext; |
1566 | for (const MachineOperand &MONext : NextI->operands()) { |
1567 | // Return true if we came across the register from the |
1568 | // previous spill instruction that is killed in NextI. |
1569 | if (isKilledReg(MONext, RegNext) && RegNext == Reg) |
1570 | return true; |
1571 | } |
1572 | } |
1573 | } |
1574 | // Return false if we didn't find spilled register. |
1575 | return false; |
1576 | } |
1577 | |
1578 | Optional<VarLocBasedLDV::VarLoc::SpillLoc> |
1579 | VarLocBasedLDV::isRestoreInstruction(const MachineInstr &MI, |
1580 | MachineFunction *MF, Register &Reg) { |
1581 | if (!MI.hasOneMemOperand()) |
1582 | return None; |
1583 | |
1584 | // FIXME: Handle folded restore instructions with more than one memory |
1585 | // operand. |
1586 | if (MI.getRestoreSize(TII)) { |
1587 | Reg = MI.getOperand(0).getReg(); |
1588 | return extractSpillBaseRegAndOffset(MI); |
1589 | } |
1590 | return None; |
1591 | } |
1592 | |
1593 | /// A spilled register may indicate that we have to end the current range of |
1594 | /// a variable and create a new one for the spill location. |
1595 | /// A restored register may indicate the reverse situation. |
1596 | /// We don't want to insert any instructions in process(), so we just create |
1597 | /// the DBG_VALUE without inserting it and keep track of it in \p Transfers. |
1598 | /// It will be inserted into the BB when we're done iterating over the |
1599 | /// instructions. |
1600 | void VarLocBasedLDV::transferSpillOrRestoreInst(MachineInstr &MI, |
1601 | OpenRangesSet &OpenRanges, |
1602 | VarLocMap &VarLocIDs, |
1603 | TransferMap &Transfers) { |
1604 | MachineFunction *MF = MI.getMF(); |
1605 | TransferKind TKind; |
1606 | Register Reg; |
1607 | Optional<VarLoc::SpillLoc> Loc; |
1608 | |
1609 | LLVM_DEBUG(dbgs() << "Examining instruction: "; MI.dump();)do { } while (false); |
1610 | |
1611 | // First, if there are any DBG_VALUEs pointing at a spill slot that is |
1612 | // written to, then close the variable location. The value in memory |
1613 | // will have changed. |
1614 | VarLocsInRange KillSet; |
1615 | if (isSpillInstruction(MI, MF)) { |
1616 | Loc = extractSpillBaseRegAndOffset(MI); |
1617 | for (uint64_t ID : OpenRanges.getSpillVarLocs()) { |
1618 | LocIndex Idx = LocIndex::fromRawInteger(ID); |
1619 | const VarLoc &VL = VarLocIDs[Idx]; |
1620 | assert(VL.containsSpillLocs() && "Broken VarLocSet?")((void)0); |
1621 | if (VL.usesSpillLoc(*Loc)) { |
1622 | // This location is overwritten by the current instruction -- terminate |
1623 | // the open range, and insert an explicit DBG_VALUE $noreg. |
1624 | // |
1625 | // Doing this at a later stage would require re-interpreting all |
1626 | // DBG_VALUes and DIExpressions to identify whether they point at |
1627 | // memory, and then analysing all memory writes to see if they |
1628 | // overwrite that memory, which is expensive. |
1629 | // |
1630 | // At this stage, we already know which DBG_VALUEs are for spills and |
1631 | // where they are located; it's best to fix handle overwrites now. |
1632 | KillSet.insert(ID); |
1633 | unsigned SpillLocIdx = VL.getSpillLocIdx(*Loc); |
1634 | VarLoc::MachineLoc OldLoc = VL.Locs[SpillLocIdx]; |
1635 | VarLoc UndefVL = VarLoc::CreateCopyLoc(VL, OldLoc, 0); |
1636 | LocIndices UndefLocIDs = VarLocIDs.insert(UndefVL); |
1637 | Transfers.push_back({&MI, UndefLocIDs.back()}); |
1638 | } |
1639 | } |
1640 | OpenRanges.erase(KillSet, VarLocIDs, LocIndex::kSpillLocation); |
1641 | } |
1642 | |
1643 | // Try to recognise spill and restore instructions that may create a new |
1644 | // variable location. |
1645 | if (isLocationSpill(MI, MF, Reg)) { |
1646 | TKind = TransferKind::TransferSpill; |
1647 | LLVM_DEBUG(dbgs() << "Recognized as spill: "; MI.dump();)do { } while (false); |
1648 | LLVM_DEBUG(dbgs() << "Register: " << Reg << " " << printReg(Reg, TRI)do { } while (false) |
1649 | << "\n")do { } while (false); |
1650 | } else { |
1651 | if (!(Loc = isRestoreInstruction(MI, MF, Reg))) |
1652 | return; |
1653 | TKind = TransferKind::TransferRestore; |
1654 | LLVM_DEBUG(dbgs() << "Recognized as restore: "; MI.dump();)do { } while (false); |
1655 | LLVM_DEBUG(dbgs() << "Register: " << Reg << " " << printReg(Reg, TRI)do { } while (false) |
1656 | << "\n")do { } while (false); |
1657 | } |
1658 | // Check if the register or spill location is the location of a debug value. |
1659 | auto TransferCandidates = OpenRanges.getEmptyVarLocRange(); |
1660 | if (TKind == TransferKind::TransferSpill) |
1661 | TransferCandidates = OpenRanges.getRegisterVarLocs(Reg); |
1662 | else if (TKind == TransferKind::TransferRestore) |
1663 | TransferCandidates = OpenRanges.getSpillVarLocs(); |
1664 | for (uint64_t ID : TransferCandidates) { |
1665 | LocIndex Idx = LocIndex::fromRawInteger(ID); |
1666 | const VarLoc &VL = VarLocIDs[Idx]; |
1667 | unsigned LocIdx; |
1668 | if (TKind == TransferKind::TransferSpill) { |
1669 | assert(VL.usesReg(Reg) && "Broken VarLocSet?")((void)0); |
1670 | LLVM_DEBUG(dbgs() << "Spilling Register " << printReg(Reg, TRI) << '('do { } while (false) |
1671 | << VL.Var.getVariable()->getName() << ")\n")do { } while (false); |
1672 | LocIdx = VL.getRegIdx(Reg); |
1673 | } else { |
1674 | assert(TKind == TransferKind::TransferRestore && VL.containsSpillLocs() &&((void)0) |
1675 | "Broken VarLocSet?")((void)0); |
1676 | if (!VL.usesSpillLoc(*Loc)) |
1677 | // The spill location is not the location of a debug value. |
1678 | continue; |
1679 | LLVM_DEBUG(dbgs() << "Restoring Register " << printReg(Reg, TRI) << '('do { } while (false) |
1680 | << VL.Var.getVariable()->getName() << ")\n")do { } while (false); |
1681 | LocIdx = VL.getSpillLocIdx(*Loc); |
1682 | } |
1683 | VarLoc::MachineLoc MLoc = VL.Locs[LocIdx]; |
1684 | insertTransferDebugPair(MI, OpenRanges, Transfers, VarLocIDs, Idx, TKind, |
1685 | MLoc, Reg); |
1686 | // FIXME: A comment should explain why it's correct to return early here, |
1687 | // if that is in fact correct. |
1688 | return; |
1689 | } |
1690 | } |
1691 | |
1692 | /// If \p MI is a register copy instruction, that copies a previously tracked |
1693 | /// value from one register to another register that is callee saved, we |
1694 | /// create new DBG_VALUE instruction described with copy destination register. |
1695 | void VarLocBasedLDV::transferRegisterCopy(MachineInstr &MI, |
1696 | OpenRangesSet &OpenRanges, |
1697 | VarLocMap &VarLocIDs, |
1698 | TransferMap &Transfers) { |
1699 | auto DestSrc = TII->isCopyInstr(MI); |
1700 | if (!DestSrc) |
1701 | return; |
1702 | |
1703 | const MachineOperand *DestRegOp = DestSrc->Destination; |
1704 | const MachineOperand *SrcRegOp = DestSrc->Source; |
1705 | |
1706 | if (!DestRegOp->isDef()) |
1707 | return; |
1708 | |
1709 | auto isCalleeSavedReg = [&](Register Reg) { |
1710 | for (MCRegAliasIterator RAI(Reg, TRI, true); RAI.isValid(); ++RAI) |
1711 | if (CalleeSavedRegs.test(*RAI)) |
1712 | return true; |
1713 | return false; |
1714 | }; |
1715 | |
1716 | Register SrcReg = SrcRegOp->getReg(); |
1717 | Register DestReg = DestRegOp->getReg(); |
1718 | |
1719 | // We want to recognize instructions where destination register is callee |
1720 | // saved register. If register that could be clobbered by the call is |
1721 | // included, there would be a great chance that it is going to be clobbered |
1722 | // soon. It is more likely that previous register location, which is callee |
1723 | // saved, is going to stay unclobbered longer, even if it is killed. |
1724 | if (!isCalleeSavedReg(DestReg)) |
1725 | return; |
1726 | |
1727 | // Remember an entry value movement. If we encounter a new debug value of |
1728 | // a parameter describing only a moving of the value around, rather then |
1729 | // modifying it, we are still able to use the entry value if needed. |
1730 | if (isRegOtherThanSPAndFP(*DestRegOp, MI, TRI)) { |
1731 | for (uint64_t ID : OpenRanges.getEntryValueBackupVarLocs()) { |
1732 | LocIndex Idx = LocIndex::fromRawInteger(ID); |
1733 | const VarLoc &VL = VarLocIDs[Idx]; |
1734 | if (VL.isEntryValueBackupReg(SrcReg)) { |
1735 | LLVM_DEBUG(dbgs() << "Copy of the entry value: "; MI.dump();)do { } while (false); |
1736 | VarLoc EntryValLocCopyBackup = |
1737 | VarLoc::CreateEntryCopyBackupLoc(VL.MI, LS, VL.Expr, DestReg); |
1738 | // Stop tracking the original entry value. |
1739 | OpenRanges.erase(VL); |
1740 | |
1741 | // Start tracking the entry value copy. |
1742 | LocIndices EntryValCopyLocIDs = VarLocIDs.insert(EntryValLocCopyBackup); |
1743 | OpenRanges.insert(EntryValCopyLocIDs, EntryValLocCopyBackup); |
1744 | break; |
1745 | } |
1746 | } |
1747 | } |
1748 | |
1749 | if (!SrcRegOp->isKill()) |
1750 | return; |
1751 | |
1752 | for (uint64_t ID : OpenRanges.getRegisterVarLocs(SrcReg)) { |
1753 | LocIndex Idx = LocIndex::fromRawInteger(ID); |
1754 | assert(VarLocIDs[Idx].usesReg(SrcReg) && "Broken VarLocSet?")((void)0); |
1755 | VarLoc::MachineLocValue Loc; |
1756 | Loc.RegNo = SrcReg; |
1757 | VarLoc::MachineLoc MLoc{VarLoc::MachineLocKind::RegisterKind, Loc}; |
1758 | insertTransferDebugPair(MI, OpenRanges, Transfers, VarLocIDs, Idx, |
1759 | TransferKind::TransferCopy, MLoc, DestReg); |
1760 | // FIXME: A comment should explain why it's correct to return early here, |
1761 | // if that is in fact correct. |
1762 | return; |
1763 | } |
1764 | } |
1765 | |
1766 | /// Terminate all open ranges at the end of the current basic block. |
1767 | bool VarLocBasedLDV::transferTerminator(MachineBasicBlock *CurMBB, |
1768 | OpenRangesSet &OpenRanges, |
1769 | VarLocInMBB &OutLocs, |
1770 | const VarLocMap &VarLocIDs) { |
1771 | bool Changed = false; |
1772 | LLVM_DEBUG({do { } while (false) |
1773 | VarVec VarLocs;do { } while (false) |
1774 | OpenRanges.getUniqueVarLocs(VarLocs, VarLocIDs);do { } while (false) |
1775 | for (VarLoc &VL : VarLocs) {do { } while (false) |
1776 | // Copy OpenRanges to OutLocs, if not already present.do { } while (false) |
1777 | dbgs() << "Add to OutLocs in MBB #" << CurMBB->getNumber() << ": ";do { } while (false) |
1778 | VL.dump(TRI);do { } while (false) |
1779 | }do { } while (false) |
1780 | })do { } while (false); |
1781 | VarLocSet &VLS = getVarLocsInMBB(CurMBB, OutLocs); |
1782 | Changed = VLS != OpenRanges.getVarLocs(); |
1783 | // New OutLocs set may be different due to spill, restore or register |
1784 | // copy instruction processing. |
1785 | if (Changed) |
1786 | VLS = OpenRanges.getVarLocs(); |
1787 | OpenRanges.clear(); |
1788 | return Changed; |
1789 | } |
1790 | |
1791 | /// Accumulate a mapping between each DILocalVariable fragment and other |
1792 | /// fragments of that DILocalVariable which overlap. This reduces work during |
1793 | /// the data-flow stage from "Find any overlapping fragments" to "Check if the |
1794 | /// known-to-overlap fragments are present". |
1795 | /// \param MI A previously unprocessed DEBUG_VALUE instruction to analyze for |
1796 | /// fragment usage. |
1797 | /// \param SeenFragments Map from DILocalVariable to all fragments of that |
1798 | /// Variable which are known to exist. |
1799 | /// \param OverlappingFragments The overlap map being constructed, from one |
1800 | /// Var/Fragment pair to a vector of fragments known to overlap. |
1801 | void VarLocBasedLDV::accumulateFragmentMap(MachineInstr &MI, |
1802 | VarToFragments &SeenFragments, |
1803 | OverlapMap &OverlappingFragments) { |
1804 | DebugVariable MIVar(MI.getDebugVariable(), MI.getDebugExpression(), |
1805 | MI.getDebugLoc()->getInlinedAt()); |
1806 | FragmentInfo ThisFragment = MIVar.getFragmentOrDefault(); |
1807 | |
1808 | // If this is the first sighting of this variable, then we are guaranteed |
1809 | // there are currently no overlapping fragments either. Initialize the set |
1810 | // of seen fragments, record no overlaps for the current one, and return. |
1811 | auto SeenIt = SeenFragments.find(MIVar.getVariable()); |
1812 | if (SeenIt == SeenFragments.end()) { |
1813 | SmallSet<FragmentInfo, 4> OneFragment; |
1814 | OneFragment.insert(ThisFragment); |
1815 | SeenFragments.insert({MIVar.getVariable(), OneFragment}); |
1816 | |
1817 | OverlappingFragments.insert({{MIVar.getVariable(), ThisFragment}, {}}); |
1818 | return; |
1819 | } |
1820 | |
1821 | // If this particular Variable/Fragment pair already exists in the overlap |
1822 | // map, it has already been accounted for. |
1823 | auto IsInOLapMap = |
1824 | OverlappingFragments.insert({{MIVar.getVariable(), ThisFragment}, {}}); |
1825 | if (!IsInOLapMap.second) |
1826 | return; |
1827 | |
1828 | auto &ThisFragmentsOverlaps = IsInOLapMap.first->second; |
1829 | auto &AllSeenFragments = SeenIt->second; |
1830 | |
1831 | // Otherwise, examine all other seen fragments for this variable, with "this" |
1832 | // fragment being a previously unseen fragment. Record any pair of |
1833 | // overlapping fragments. |
1834 | for (auto &ASeenFragment : AllSeenFragments) { |
1835 | // Does this previously seen fragment overlap? |
1836 | if (DIExpression::fragmentsOverlap(ThisFragment, ASeenFragment)) { |
1837 | // Yes: Mark the current fragment as being overlapped. |
1838 | ThisFragmentsOverlaps.push_back(ASeenFragment); |
1839 | // Mark the previously seen fragment as being overlapped by the current |
1840 | // one. |
1841 | auto ASeenFragmentsOverlaps = |
1842 | OverlappingFragments.find({MIVar.getVariable(), ASeenFragment}); |
1843 | assert(ASeenFragmentsOverlaps != OverlappingFragments.end() &&((void)0) |
1844 | "Previously seen var fragment has no vector of overlaps")((void)0); |
1845 | ASeenFragmentsOverlaps->second.push_back(ThisFragment); |
1846 | } |
1847 | } |
1848 | |
1849 | AllSeenFragments.insert(ThisFragment); |
1850 | } |
1851 | |
1852 | /// This routine creates OpenRanges. |
1853 | void VarLocBasedLDV::process(MachineInstr &MI, OpenRangesSet &OpenRanges, |
1854 | VarLocMap &VarLocIDs, TransferMap &Transfers) { |
1855 | transferDebugValue(MI, OpenRanges, VarLocIDs); |
1856 | transferRegisterDef(MI, OpenRanges, VarLocIDs, Transfers); |
1857 | transferRegisterCopy(MI, OpenRanges, VarLocIDs, Transfers); |
1858 | transferSpillOrRestoreInst(MI, OpenRanges, VarLocIDs, Transfers); |
1859 | } |
1860 | |
1861 | /// This routine joins the analysis results of all incoming edges in @MBB by |
1862 | /// inserting a new DBG_VALUE instruction at the start of the @MBB - if the same |
1863 | /// source variable in all the predecessors of @MBB reside in the same location. |
1864 | bool VarLocBasedLDV::join( |
1865 | MachineBasicBlock &MBB, VarLocInMBB &OutLocs, VarLocInMBB &InLocs, |
1866 | const VarLocMap &VarLocIDs, |
1867 | SmallPtrSet<const MachineBasicBlock *, 16> &Visited, |
1868 | SmallPtrSetImpl<const MachineBasicBlock *> &ArtificialBlocks) { |
1869 | LLVM_DEBUG(dbgs() << "join MBB: " << MBB.getNumber() << "\n")do { } while (false); |
1870 | |
1871 | VarLocSet InLocsT(Alloc); // Temporary incoming locations. |
1872 | |
1873 | // For all predecessors of this MBB, find the set of VarLocs that |
1874 | // can be joined. |
1875 | int NumVisited = 0; |
1876 | for (auto p : MBB.predecessors()) { |
1877 | // Ignore backedges if we have not visited the predecessor yet. As the |
1878 | // predecessor hasn't yet had locations propagated into it, most locations |
1879 | // will not yet be valid, so treat them as all being uninitialized and |
1880 | // potentially valid. If a location guessed to be correct here is |
1881 | // invalidated later, we will remove it when we revisit this block. |
1882 | if (!Visited.count(p)) { |
1883 | LLVM_DEBUG(dbgs() << " ignoring unvisited pred MBB: " << p->getNumber()do { } while (false) |
1884 | << "\n")do { } while (false); |
1885 | continue; |
1886 | } |
1887 | auto OL = OutLocs.find(p); |
1888 | // Join is null in case of empty OutLocs from any of the pred. |
1889 | if (OL == OutLocs.end()) |
1890 | return false; |
1891 | |
1892 | // Just copy over the Out locs to incoming locs for the first visited |
1893 | // predecessor, and for all other predecessors join the Out locs. |
1894 | VarLocSet &OutLocVLS = *OL->second.get(); |
1895 | if (!NumVisited) |
1896 | InLocsT = OutLocVLS; |
1897 | else |
1898 | InLocsT &= OutLocVLS; |
1899 | |
1900 | LLVM_DEBUG({do { } while (false) |
1901 | if (!InLocsT.empty()) {do { } while (false) |
1902 | VarVec VarLocs;do { } while (false) |
1903 | collectAllVarLocs(VarLocs, InLocsT, VarLocIDs);do { } while (false) |
1904 | for (const VarLoc &VL : VarLocs)do { } while (false) |
1905 | dbgs() << " gathered candidate incoming var: "do { } while (false) |
1906 | << VL.Var.getVariable()->getName() << "\n";do { } while (false) |
1907 | }do { } while (false) |
1908 | })do { } while (false); |
1909 | |
1910 | NumVisited++; |
1911 | } |
1912 | |
1913 | // Filter out DBG_VALUES that are out of scope. |
1914 | VarLocSet KillSet(Alloc); |
1915 | bool IsArtificial = ArtificialBlocks.count(&MBB); |
1916 | if (!IsArtificial) { |
1917 | for (uint64_t ID : InLocsT) { |
1918 | LocIndex Idx = LocIndex::fromRawInteger(ID); |
1919 | if (!VarLocIDs[Idx].dominates(LS, MBB)) { |
1920 | KillSet.set(ID); |
1921 | LLVM_DEBUG({do { } while (false) |
1922 | auto Name = VarLocIDs[Idx].Var.getVariable()->getName();do { } while (false) |
1923 | dbgs() << " killing " << Name << ", it doesn't dominate MBB\n";do { } while (false) |
1924 | })do { } while (false); |
1925 | } |
1926 | } |
1927 | } |
1928 | InLocsT.intersectWithComplement(KillSet); |
1929 | |
1930 | // As we are processing blocks in reverse post-order we |
1931 | // should have processed at least one predecessor, unless it |
1932 | // is the entry block which has no predecessor. |
1933 | assert((NumVisited || MBB.pred_empty()) &&((void)0) |
1934 | "Should have processed at least one predecessor")((void)0); |
1935 | |
1936 | VarLocSet &ILS = getVarLocsInMBB(&MBB, InLocs); |
1937 | bool Changed = false; |
1938 | if (ILS != InLocsT) { |
1939 | ILS = InLocsT; |
1940 | Changed = true; |
1941 | } |
1942 | |
1943 | return Changed; |
1944 | } |
1945 | |
1946 | void VarLocBasedLDV::flushPendingLocs(VarLocInMBB &PendingInLocs, |
1947 | VarLocMap &VarLocIDs) { |
1948 | // PendingInLocs records all locations propagated into blocks, which have |
1949 | // not had DBG_VALUE insts created. Go through and create those insts now. |
1950 | for (auto &Iter : PendingInLocs) { |
1951 | // Map is keyed on a constant pointer, unwrap it so we can insert insts. |
1952 | auto &MBB = const_cast<MachineBasicBlock &>(*Iter.first); |
1953 | VarLocSet &Pending = *Iter.second.get(); |
1954 | |
1955 | SmallVector<VarLoc, 32> VarLocs; |
1956 | collectAllVarLocs(VarLocs, Pending, VarLocIDs); |
1957 | |
1958 | for (VarLoc DiffIt : VarLocs) { |
1959 | // The ID location is live-in to MBB -- work out what kind of machine |
1960 | // location it is and create a DBG_VALUE. |
1961 | if (DiffIt.isEntryBackupLoc()) |
1962 | continue; |
1963 | MachineInstr *MI = DiffIt.BuildDbgValue(*MBB.getParent()); |
1964 | MBB.insert(MBB.instr_begin(), MI); |
1965 | |
1966 | (void)MI; |
1967 | LLVM_DEBUG(dbgs() << "Inserted: "; MI->dump();)do { } while (false); |
1968 | } |
1969 | } |
1970 | } |
1971 | |
1972 | bool VarLocBasedLDV::isEntryValueCandidate( |
1973 | const MachineInstr &MI, const DefinedRegsSet &DefinedRegs) const { |
1974 | assert(MI.isDebugValue() && "This must be DBG_VALUE.")((void)0); |
1975 | |
1976 | // TODO: Add support for local variables that are expressed in terms of |
1977 | // parameters entry values. |
1978 | // TODO: Add support for modified arguments that can be expressed |
1979 | // by using its entry value. |
1980 | auto *DIVar = MI.getDebugVariable(); |
1981 | if (!DIVar->isParameter()) |
1982 | return false; |
1983 | |
1984 | // Do not consider parameters that belong to an inlined function. |
1985 | if (MI.getDebugLoc()->getInlinedAt()) |
1986 | return false; |
1987 | |
1988 | // Only consider parameters that are described using registers. Parameters |
1989 | // that are passed on the stack are not yet supported, so ignore debug |
1990 | // values that are described by the frame or stack pointer. |
1991 | if (!isRegOtherThanSPAndFP(MI.getDebugOperand(0), MI, TRI)) |
1992 | return false; |
1993 | |
1994 | // If a parameter's value has been propagated from the caller, then the |
1995 | // parameter's DBG_VALUE may be described using a register defined by some |
1996 | // instruction in the entry block, in which case we shouldn't create an |
1997 | // entry value. |
1998 | if (DefinedRegs.count(MI.getDebugOperand(0).getReg())) |
1999 | return false; |
2000 | |
2001 | // TODO: Add support for parameters that have a pre-existing debug expressions |
2002 | // (e.g. fragments). |
2003 | if (MI.getDebugExpression()->getNumElements() > 0) |
2004 | return false; |
2005 | |
2006 | return true; |
2007 | } |
2008 | |
2009 | /// Collect all register defines (including aliases) for the given instruction. |
2010 | static void collectRegDefs(const MachineInstr &MI, DefinedRegsSet &Regs, |
2011 | const TargetRegisterInfo *TRI) { |
2012 | for (const MachineOperand &MO : MI.operands()) |
2013 | if (MO.isReg() && MO.isDef() && MO.getReg()) |
2014 | for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid(); ++AI) |
2015 | Regs.insert(*AI); |
2016 | } |
2017 | |
2018 | /// This routine records the entry values of function parameters. The values |
2019 | /// could be used as backup values. If we loose the track of some unmodified |
2020 | /// parameters, the backup values will be used as a primary locations. |
2021 | void VarLocBasedLDV::recordEntryValue(const MachineInstr &MI, |
2022 | const DefinedRegsSet &DefinedRegs, |
2023 | OpenRangesSet &OpenRanges, |
2024 | VarLocMap &VarLocIDs) { |
2025 | if (TPC) { |
2026 | auto &TM = TPC->getTM<TargetMachine>(); |
2027 | if (!TM.Options.ShouldEmitDebugEntryValues()) |
2028 | return; |
2029 | } |
2030 | |
2031 | DebugVariable V(MI.getDebugVariable(), MI.getDebugExpression(), |
2032 | MI.getDebugLoc()->getInlinedAt()); |
2033 | |
2034 | if (!isEntryValueCandidate(MI, DefinedRegs) || |
2035 | OpenRanges.getEntryValueBackup(V)) |
2036 | return; |
2037 | |
2038 | LLVM_DEBUG(dbgs() << "Creating the backup entry location: "; MI.dump();)do { } while (false); |
2039 | |
2040 | // Create the entry value and use it as a backup location until it is |
2041 | // valid. It is valid until a parameter is not changed. |
2042 | DIExpression *NewExpr = |
2043 | DIExpression::prepend(MI.getDebugExpression(), DIExpression::EntryValue); |
2044 | VarLoc EntryValLocAsBackup = VarLoc::CreateEntryBackupLoc(MI, LS, NewExpr); |
2045 | LocIndices EntryValLocIDs = VarLocIDs.insert(EntryValLocAsBackup); |
2046 | OpenRanges.insert(EntryValLocIDs, EntryValLocAsBackup); |
2047 | } |
2048 | |
2049 | /// Calculate the liveness information for the given machine function and |
2050 | /// extend ranges across basic blocks. |
2051 | bool VarLocBasedLDV::ExtendRanges(MachineFunction &MF, TargetPassConfig *TPC) { |
2052 | LLVM_DEBUG(dbgs() << "\nDebug Range Extension\n")do { } while (false); |
2053 | |
2054 | if (!MF.getFunction().getSubprogram()) |
2055 | // VarLocBaseLDV will already have removed all DBG_VALUEs. |
2056 | return false; |
2057 | |
2058 | // Skip functions from NoDebug compilation units. |
2059 | if (MF.getFunction().getSubprogram()->getUnit()->getEmissionKind() == |
2060 | DICompileUnit::NoDebug) |
2061 | return false; |
2062 | |
2063 | TRI = MF.getSubtarget().getRegisterInfo(); |
2064 | TII = MF.getSubtarget().getInstrInfo(); |
2065 | TFI = MF.getSubtarget().getFrameLowering(); |
2066 | TFI->getCalleeSaves(MF, CalleeSavedRegs); |
2067 | this->TPC = TPC; |
2068 | LS.initialize(MF); |
2069 | |
2070 | bool Changed = false; |
2071 | bool OLChanged = false; |
2072 | bool MBBJoined = false; |
2073 | |
2074 | VarLocMap VarLocIDs; // Map VarLoc<>unique ID for use in bitvectors. |
2075 | OverlapMap OverlapFragments; // Map of overlapping variable fragments. |
2076 | OpenRangesSet OpenRanges(Alloc, OverlapFragments); |
2077 | // Ranges that are open until end of bb. |
2078 | VarLocInMBB OutLocs; // Ranges that exist beyond bb. |
2079 | VarLocInMBB InLocs; // Ranges that are incoming after joining. |
2080 | TransferMap Transfers; // DBG_VALUEs associated with transfers (such as |
2081 | // spills, copies and restores). |
2082 | |
2083 | VarToFragments SeenFragments; |
2084 | |
2085 | // Blocks which are artificial, i.e. blocks which exclusively contain |
2086 | // instructions without locations, or with line 0 locations. |
2087 | SmallPtrSet<const MachineBasicBlock *, 16> ArtificialBlocks; |
2088 | |
2089 | DenseMap<unsigned int, MachineBasicBlock *> OrderToBB; |
2090 | DenseMap<MachineBasicBlock *, unsigned int> BBToOrder; |
2091 | std::priority_queue<unsigned int, std::vector<unsigned int>, |
2092 | std::greater<unsigned int>> |
2093 | Worklist; |
2094 | std::priority_queue<unsigned int, std::vector<unsigned int>, |
2095 | std::greater<unsigned int>> |
2096 | Pending; |
2097 | |
2098 | // Set of register defines that are seen when traversing the entry block |
2099 | // looking for debug entry value candidates. |
2100 | DefinedRegsSet DefinedRegs; |
2101 | |
2102 | // Only in the case of entry MBB collect DBG_VALUEs representing |
2103 | // function parameters in order to generate debug entry values for them. |
2104 | MachineBasicBlock &First_MBB = *(MF.begin()); |
2105 | for (auto &MI : First_MBB) { |
2106 | collectRegDefs(MI, DefinedRegs, TRI); |
2107 | if (MI.isDebugValue()) |
2108 | recordEntryValue(MI, DefinedRegs, OpenRanges, VarLocIDs); |
2109 | } |
2110 | |
2111 | // Initialize per-block structures and scan for fragment overlaps. |
2112 | for (auto &MBB : MF) |
2113 | for (auto &MI : MBB) |
2114 | if (MI.isDebugValue()) |
2115 | accumulateFragmentMap(MI, SeenFragments, OverlapFragments); |
2116 | |
2117 | auto hasNonArtificialLocation = [](const MachineInstr &MI) -> bool { |
2118 | if (const DebugLoc &DL = MI.getDebugLoc()) |
2119 | return DL.getLine() != 0; |
2120 | return false; |
2121 | }; |
2122 | for (auto &MBB : MF) |
2123 | if (none_of(MBB.instrs(), hasNonArtificialLocation)) |
2124 | ArtificialBlocks.insert(&MBB); |
2125 | |
2126 | LLVM_DEBUG(printVarLocInMBB(MF, OutLocs, VarLocIDs,do { } while (false) |
2127 | "OutLocs after initialization", dbgs()))do { } while (false); |
2128 | |
2129 | ReversePostOrderTraversal<MachineFunction *> RPOT(&MF); |
2130 | unsigned int RPONumber = 0; |
2131 | for (MachineBasicBlock *MBB : RPOT) { |
2132 | OrderToBB[RPONumber] = MBB; |
2133 | BBToOrder[MBB] = RPONumber; |
2134 | Worklist.push(RPONumber); |
2135 | ++RPONumber; |
2136 | } |
2137 | |
2138 | if (RPONumber > InputBBLimit) { |
2139 | unsigned NumInputDbgValues = 0; |
2140 | for (auto &MBB : MF) |
2141 | for (auto &MI : MBB) |
2142 | if (MI.isDebugValue()) |
2143 | ++NumInputDbgValues; |
2144 | if (NumInputDbgValues > InputDbgValueLimit) { |
2145 | LLVM_DEBUG(dbgs() << "Disabling VarLocBasedLDV: " << MF.getName()do { } while (false) |
2146 | << " has " << RPONumber << " basic blocks and "do { } while (false) |
2147 | << NumInputDbgValuesdo { } while (false) |
2148 | << " input DBG_VALUEs, exceeding limits.\n")do { } while (false); |
2149 | return false; |
2150 | } |
2151 | } |
2152 | |
2153 | // This is a standard "union of predecessor outs" dataflow problem. |
2154 | // To solve it, we perform join() and process() using the two worklist method |
2155 | // until the ranges converge. |
2156 | // Ranges have converged when both worklists are empty. |
2157 | SmallPtrSet<const MachineBasicBlock *, 16> Visited; |
2158 | while (!Worklist.empty() || !Pending.empty()) { |
2159 | // We track what is on the pending worklist to avoid inserting the same |
2160 | // thing twice. We could avoid this with a custom priority queue, but this |
2161 | // is probably not worth it. |
2162 | SmallPtrSet<MachineBasicBlock *, 16> OnPending; |
2163 | LLVM_DEBUG(dbgs() << "Processing Worklist\n")do { } while (false); |
2164 | while (!Worklist.empty()) { |
2165 | MachineBasicBlock *MBB = OrderToBB[Worklist.top()]; |
2166 | Worklist.pop(); |
2167 | MBBJoined = join(*MBB, OutLocs, InLocs, VarLocIDs, Visited, |
2168 | ArtificialBlocks); |
2169 | MBBJoined |= Visited.insert(MBB).second; |
2170 | if (MBBJoined) { |
2171 | MBBJoined = false; |
Value stored to 'MBBJoined' is never read | |
2172 | Changed = true; |
2173 | // Now that we have started to extend ranges across BBs we need to |
2174 | // examine spill, copy and restore instructions to see whether they |
2175 | // operate with registers that correspond to user variables. |
2176 | // First load any pending inlocs. |
2177 | OpenRanges.insertFromLocSet(getVarLocsInMBB(MBB, InLocs), VarLocIDs); |
2178 | for (auto &MI : *MBB) |
2179 | process(MI, OpenRanges, VarLocIDs, Transfers); |
2180 | OLChanged |= transferTerminator(MBB, OpenRanges, OutLocs, VarLocIDs); |
2181 | |
2182 | LLVM_DEBUG(printVarLocInMBB(MF, OutLocs, VarLocIDs,do { } while (false) |
2183 | "OutLocs after propagating", dbgs()))do { } while (false); |
2184 | LLVM_DEBUG(printVarLocInMBB(MF, InLocs, VarLocIDs,do { } while (false) |
2185 | "InLocs after propagating", dbgs()))do { } while (false); |
2186 | |
2187 | if (OLChanged) { |
2188 | OLChanged = false; |
2189 | for (auto s : MBB->successors()) |
2190 | if (OnPending.insert(s).second) { |
2191 | Pending.push(BBToOrder[s]); |
2192 | } |
2193 | } |
2194 | } |
2195 | } |
2196 | Worklist.swap(Pending); |
2197 | // At this point, pending must be empty, since it was just the empty |
2198 | // worklist |
2199 | assert(Pending.empty() && "Pending should be empty")((void)0); |
2200 | } |
2201 | |
2202 | // Add any DBG_VALUE instructions created by location transfers. |
2203 | for (auto &TR : Transfers) { |
2204 | assert(!TR.TransferInst->isTerminator() &&((void)0) |
2205 | "Cannot insert DBG_VALUE after terminator")((void)0); |
2206 | MachineBasicBlock *MBB = TR.TransferInst->getParent(); |
2207 | const VarLoc &VL = VarLocIDs[TR.LocationID]; |
2208 | MachineInstr *MI = VL.BuildDbgValue(MF); |
2209 | MBB->insertAfterBundle(TR.TransferInst->getIterator(), MI); |
2210 | } |
2211 | Transfers.clear(); |
2212 | |
2213 | // Deferred inlocs will not have had any DBG_VALUE insts created; do |
2214 | // that now. |
2215 | flushPendingLocs(InLocs, VarLocIDs); |
2216 | |
2217 | LLVM_DEBUG(printVarLocInMBB(MF, OutLocs, VarLocIDs, "Final OutLocs", dbgs()))do { } while (false); |
2218 | LLVM_DEBUG(printVarLocInMBB(MF, InLocs, VarLocIDs, "Final InLocs", dbgs()))do { } while (false); |
2219 | return Changed; |
2220 | } |
2221 | |
2222 | LDVImpl * |
2223 | llvm::makeVarLocBasedLiveDebugValues() |
2224 | { |
2225 | return new VarLocBasedLDV(); |
2226 | } |