Bug Summary

File:lib/CodeGen/LiveDebugValues.cpp
Warning:line 922, column 9
Value stored to 'MBBJoined' is never read

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name LiveDebugValues.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-9/lib/clang/9.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen -I /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/include -I /build/llvm-toolchain-snapshot-9~svn362543/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/9.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-9/lib/clang/9.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-9~svn362543/build-llvm/lib/CodeGen -fdebug-prefix-map=/build/llvm-toolchain-snapshot-9~svn362543=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2019-06-05-060531-1271-1 -x c++ /build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp -faddrsig
1//===- LiveDebugValues.cpp - Tracking Debug Value MIs ---------------------===//
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/// This pass implements a data flow analysis that propagates debug location
10/// information by inserting additional DBG_VALUE instructions into the machine
11/// instruction stream. The pass internally builds debug location liveness
12/// ranges to determine the points where additional DBG_VALUEs need to be
13/// inserted.
14///
15/// This is a separate pass from DbgValueHistoryCalculator to facilitate
16/// testing and improve modularity.
17///
18//===----------------------------------------------------------------------===//
19
20#include "llvm/ADT/DenseMap.h"
21#include "llvm/ADT/PostOrderIterator.h"
22#include "llvm/ADT/SmallPtrSet.h"
23#include "llvm/ADT/SmallVector.h"
24#include "llvm/ADT/SparseBitVector.h"
25#include "llvm/ADT/Statistic.h"
26#include "llvm/ADT/UniqueVector.h"
27#include "llvm/CodeGen/LexicalScopes.h"
28#include "llvm/CodeGen/MachineBasicBlock.h"
29#include "llvm/CodeGen/MachineFrameInfo.h"
30#include "llvm/CodeGen/MachineFunction.h"
31#include "llvm/CodeGen/MachineFunctionPass.h"
32#include "llvm/CodeGen/MachineInstr.h"
33#include "llvm/CodeGen/MachineInstrBuilder.h"
34#include "llvm/CodeGen/MachineMemOperand.h"
35#include "llvm/CodeGen/MachineOperand.h"
36#include "llvm/CodeGen/PseudoSourceValue.h"
37#include "llvm/CodeGen/RegisterScavenging.h"
38#include "llvm/CodeGen/TargetFrameLowering.h"
39#include "llvm/CodeGen/TargetInstrInfo.h"
40#include "llvm/CodeGen/TargetLowering.h"
41#include "llvm/CodeGen/TargetRegisterInfo.h"
42#include "llvm/CodeGen/TargetSubtargetInfo.h"
43#include "llvm/Config/llvm-config.h"
44#include "llvm/IR/DIBuilder.h"
45#include "llvm/IR/DebugInfoMetadata.h"
46#include "llvm/IR/DebugLoc.h"
47#include "llvm/IR/Function.h"
48#include "llvm/IR/Module.h"
49#include "llvm/MC/MCRegisterInfo.h"
50#include "llvm/Pass.h"
51#include "llvm/Support/Casting.h"
52#include "llvm/Support/Compiler.h"
53#include "llvm/Support/Debug.h"
54#include "llvm/Support/raw_ostream.h"
55#include <algorithm>
56#include <cassert>
57#include <cstdint>
58#include <functional>
59#include <queue>
60#include <utility>
61#include <vector>
62
63using namespace llvm;
64
65#define DEBUG_TYPE"livedebugvalues" "livedebugvalues"
66
67STATISTIC(NumInserted, "Number of DBG_VALUE instructions inserted")static llvm::Statistic NumInserted = {"livedebugvalues", "NumInserted"
, "Number of DBG_VALUE instructions inserted", {0}, {false}};
68
69// If @MI is a DBG_VALUE with debug value described by a defined
70// register, returns the number of this register. In the other case, returns 0.
71static unsigned isDbgValueDescribedByReg(const MachineInstr &MI) {
72 assert(MI.isDebugValue() && "expected a DBG_VALUE")((MI.isDebugValue() && "expected a DBG_VALUE") ? static_cast
<void> (0) : __assert_fail ("MI.isDebugValue() && \"expected a DBG_VALUE\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 72, __PRETTY_FUNCTION__));
73 assert(MI.getNumOperands() == 4 && "malformed DBG_VALUE")((MI.getNumOperands() == 4 && "malformed DBG_VALUE") ?
static_cast<void> (0) : __assert_fail ("MI.getNumOperands() == 4 && \"malformed DBG_VALUE\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 73, __PRETTY_FUNCTION__));
74 // If location of variable is described using a register (directly
75 // or indirectly), this register is always a first operand.
76 return MI.getOperand(0).isReg() ? MI.getOperand(0).getReg() : 0;
77}
78
79namespace {
80
81class LiveDebugValues : public MachineFunctionPass {
82private:
83 const TargetRegisterInfo *TRI;
84 const TargetInstrInfo *TII;
85 const TargetFrameLowering *TFI;
86 BitVector CalleeSavedRegs;
87 LexicalScopes LS;
88
89 enum struct TransferKind { TransferCopy, TransferSpill, TransferRestore };
90
91 /// Keeps track of lexical scopes associated with a user value's source
92 /// location.
93 class UserValueScopes {
94 DebugLoc DL;
95 LexicalScopes &LS;
96 SmallPtrSet<const MachineBasicBlock *, 4> LBlocks;
97
98 public:
99 UserValueScopes(DebugLoc D, LexicalScopes &L) : DL(std::move(D)), LS(L) {}
100
101 /// Return true if current scope dominates at least one machine
102 /// instruction in a given machine basic block.
103 bool dominates(MachineBasicBlock *MBB) {
104 if (LBlocks.empty())
105 LS.getMachineBasicBlocks(DL, LBlocks);
106 return LBlocks.count(MBB) != 0 || LS.dominates(DL, MBB);
107 }
108 };
109
110 /// Based on std::pair so it can be used as an index into a DenseMap.
111 using DebugVariableBase =
112 std::pair<const DILocalVariable *, const DILocation *>;
113 /// A potentially inlined instance of a variable.
114 struct DebugVariable : public DebugVariableBase {
115 DebugVariable(const DILocalVariable *Var, const DILocation *InlinedAt)
116 : DebugVariableBase(Var, InlinedAt) {}
117
118 const DILocalVariable *getVar() const { return this->first; }
119 const DILocation *getInlinedAt() const { return this->second; }
120
121 bool operator<(const DebugVariable &DV) const {
122 if (getVar() == DV.getVar())
123 return getInlinedAt() < DV.getInlinedAt();
124 return getVar() < DV.getVar();
125 }
126 };
127
128 /// A pair of debug variable and value location.
129 struct VarLoc {
130 // The location at which a spilled variable resides. It consists of a
131 // register and an offset.
132 struct SpillLoc {
133 unsigned SpillBase;
134 int SpillOffset;
135 bool operator==(const SpillLoc &Other) const {
136 return SpillBase == Other.SpillBase && SpillOffset == Other.SpillOffset;
137 }
138 };
139
140 const DebugVariable Var;
141 const MachineInstr &MI; ///< Only used for cloning a new DBG_VALUE.
142 mutable UserValueScopes UVS;
143 enum VarLocKind {
144 InvalidKind = 0,
145 RegisterKind,
146 SpillLocKind
147 } Kind = InvalidKind;
148
149 /// The value location. Stored separately to avoid repeatedly
150 /// extracting it from MI.
151 union {
152 uint64_t RegNo;
153 SpillLoc SpillLocation;
154 uint64_t Hash;
155 } Loc;
156
157 VarLoc(const MachineInstr &MI, LexicalScopes &LS)
158 : Var(MI.getDebugVariable(), MI.getDebugLoc()->getInlinedAt()), MI(MI),
159 UVS(MI.getDebugLoc(), LS) {
160 static_assert((sizeof(Loc) == sizeof(uint64_t)),
161 "hash does not cover all members of Loc");
162 assert(MI.isDebugValue() && "not a DBG_VALUE")((MI.isDebugValue() && "not a DBG_VALUE") ? static_cast
<void> (0) : __assert_fail ("MI.isDebugValue() && \"not a DBG_VALUE\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 162, __PRETTY_FUNCTION__));
163 assert(MI.getNumOperands() == 4 && "malformed DBG_VALUE")((MI.getNumOperands() == 4 && "malformed DBG_VALUE") ?
static_cast<void> (0) : __assert_fail ("MI.getNumOperands() == 4 && \"malformed DBG_VALUE\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 163, __PRETTY_FUNCTION__));
164 if (int RegNo = isDbgValueDescribedByReg(MI)) {
165 Kind = RegisterKind;
166 Loc.RegNo = RegNo;
167 }
168 }
169
170 /// The constructor for spill locations.
171 VarLoc(const MachineInstr &MI, unsigned SpillBase, int SpillOffset,
172 LexicalScopes &LS)
173 : Var(MI.getDebugVariable(), MI.getDebugLoc()->getInlinedAt()), MI(MI),
174 UVS(MI.getDebugLoc(), LS) {
175 assert(MI.isDebugValue() && "not a DBG_VALUE")((MI.isDebugValue() && "not a DBG_VALUE") ? static_cast
<void> (0) : __assert_fail ("MI.isDebugValue() && \"not a DBG_VALUE\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 175, __PRETTY_FUNCTION__));
176 assert(MI.getNumOperands() == 4 && "malformed DBG_VALUE")((MI.getNumOperands() == 4 && "malformed DBG_VALUE") ?
static_cast<void> (0) : __assert_fail ("MI.getNumOperands() == 4 && \"malformed DBG_VALUE\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 176, __PRETTY_FUNCTION__));
177 Kind = SpillLocKind;
178 Loc.SpillLocation = {SpillBase, SpillOffset};
179 }
180
181 /// If this variable is described by a register, return it,
182 /// otherwise return 0.
183 unsigned isDescribedByReg() const {
184 if (Kind == RegisterKind)
185 return Loc.RegNo;
186 return 0;
187 }
188
189 /// Determine whether the lexical scope of this value's debug location
190 /// dominates MBB.
191 bool dominates(MachineBasicBlock &MBB) const { return UVS.dominates(&MBB); }
192
193#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
194 LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void dump() const { MI.dump(); }
195#endif
196
197 bool operator==(const VarLoc &Other) const {
198 return Var == Other.Var && Loc.Hash == Other.Loc.Hash;
199 }
200
201 /// This operator guarantees that VarLocs are sorted by Variable first.
202 bool operator<(const VarLoc &Other) const {
203 if (Var == Other.Var)
204 return Loc.Hash < Other.Loc.Hash;
205 return Var < Other.Var;
206 }
207 };
208
209 using VarLocMap = UniqueVector<VarLoc>;
210 using VarLocSet = SparseBitVector<>;
211 using VarLocInMBB = SmallDenseMap<const MachineBasicBlock *, VarLocSet>;
212 struct TransferDebugPair {
213 MachineInstr *TransferInst;
214 MachineInstr *DebugInst;
215 };
216 using TransferMap = SmallVector<TransferDebugPair, 4>;
217
218 /// This holds the working set of currently open ranges. For fast
219 /// access, this is done both as a set of VarLocIDs, and a map of
220 /// DebugVariable to recent VarLocID. Note that a DBG_VALUE ends all
221 /// previous open ranges for the same variable.
222 class OpenRangesSet {
223 VarLocSet VarLocs;
224 SmallDenseMap<DebugVariableBase, unsigned, 8> Vars;
225
226 public:
227 const VarLocSet &getVarLocs() const { return VarLocs; }
228
229 /// Terminate all open ranges for Var by removing it from the set.
230 void erase(DebugVariable Var) {
231 auto It = Vars.find(Var);
232 if (It != Vars.end()) {
233 unsigned ID = It->second;
234 VarLocs.reset(ID);
235 Vars.erase(It);
236 }
237 }
238
239 /// Terminate all open ranges listed in \c KillSet by removing
240 /// them from the set.
241 void erase(const VarLocSet &KillSet, const VarLocMap &VarLocIDs) {
242 VarLocs.intersectWithComplement(KillSet);
243 for (unsigned ID : KillSet)
244 Vars.erase(VarLocIDs[ID].Var);
245 }
246
247 /// Insert a new range into the set.
248 void insert(unsigned VarLocID, DebugVariableBase Var) {
249 VarLocs.set(VarLocID);
250 Vars.insert({Var, VarLocID});
251 }
252
253 /// Empty the set.
254 void clear() {
255 VarLocs.clear();
256 Vars.clear();
257 }
258
259 /// Return whether the set is empty or not.
260 bool empty() const {
261 assert(Vars.empty() == VarLocs.empty() && "open ranges are inconsistent")((Vars.empty() == VarLocs.empty() && "open ranges are inconsistent"
) ? static_cast<void> (0) : __assert_fail ("Vars.empty() == VarLocs.empty() && \"open ranges are inconsistent\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 261, __PRETTY_FUNCTION__));
262 return VarLocs.empty();
263 }
264 };
265
266 bool isSpillInstruction(const MachineInstr &MI, MachineFunction *MF,
267 unsigned &Reg);
268 /// If a given instruction is identified as a spill, return the spill location
269 /// and set \p Reg to the spilled register.
270 Optional<VarLoc::SpillLoc> isRestoreInstruction(const MachineInstr &MI,
271 MachineFunction *MF,
272 unsigned &Reg);
273 /// Given a spill instruction, extract the register and offset used to
274 /// address the spill location in a target independent way.
275 VarLoc::SpillLoc extractSpillBaseRegAndOffset(const MachineInstr &MI);
276 void insertTransferDebugPair(MachineInstr &MI, OpenRangesSet &OpenRanges,
277 TransferMap &Transfers, VarLocMap &VarLocIDs,
278 unsigned OldVarID, TransferKind Kind,
279 unsigned NewReg = 0);
280
281 void transferDebugValue(const MachineInstr &MI, OpenRangesSet &OpenRanges,
282 VarLocMap &VarLocIDs);
283 void transferSpillOrRestoreInst(MachineInstr &MI, OpenRangesSet &OpenRanges,
284 VarLocMap &VarLocIDs, TransferMap &Transfers);
285 void transferRegisterCopy(MachineInstr &MI, OpenRangesSet &OpenRanges,
286 VarLocMap &VarLocIDs, TransferMap &Transfers);
287 void transferRegisterDef(MachineInstr &MI, OpenRangesSet &OpenRanges,
288 const VarLocMap &VarLocIDs);
289 bool transferTerminatorInst(MachineInstr &MI, OpenRangesSet &OpenRanges,
290 VarLocInMBB &OutLocs, const VarLocMap &VarLocIDs);
291
292 bool process(MachineInstr &MI, OpenRangesSet &OpenRanges,
293 VarLocInMBB &OutLocs, VarLocMap &VarLocIDs,
294 TransferMap &Transfers, bool transferChanges);
295
296 bool join(MachineBasicBlock &MBB, VarLocInMBB &OutLocs, VarLocInMBB &InLocs,
297 const VarLocMap &VarLocIDs,
298 SmallPtrSet<const MachineBasicBlock *, 16> &Visited,
299 SmallPtrSetImpl<const MachineBasicBlock *> &ArtificialBlocks);
300
301 bool ExtendRanges(MachineFunction &MF);
302
303public:
304 static char ID;
305
306 /// Default construct and initialize the pass.
307 LiveDebugValues();
308
309 /// Tell the pass manager which passes we depend on and what
310 /// information we preserve.
311 void getAnalysisUsage(AnalysisUsage &AU) const override;
312
313 MachineFunctionProperties getRequiredProperties() const override {
314 return MachineFunctionProperties().set(
315 MachineFunctionProperties::Property::NoVRegs);
316 }
317
318 /// Print to ostream with a message.
319 void printVarLocInMBB(const MachineFunction &MF, const VarLocInMBB &V,
320 const VarLocMap &VarLocIDs, const char *msg,
321 raw_ostream &Out) const;
322
323 /// Calculate the liveness information for the given machine function.
324 bool runOnMachineFunction(MachineFunction &MF) override;
325};
326
327} // end anonymous namespace
328
329//===----------------------------------------------------------------------===//
330// Implementation
331//===----------------------------------------------------------------------===//
332
333char LiveDebugValues::ID = 0;
334
335char &llvm::LiveDebugValuesID = LiveDebugValues::ID;
336
337INITIALIZE_PASS(LiveDebugValues, DEBUG_TYPE, "Live DEBUG_VALUE analysis",static void *initializeLiveDebugValuesPassOnce(PassRegistry &
Registry) { PassInfo *PI = new PassInfo( "Live DEBUG_VALUE analysis"
, "livedebugvalues", &LiveDebugValues::ID, PassInfo::NormalCtor_t
(callDefaultCtor<LiveDebugValues>), false, false); Registry
.registerPass(*PI, true); return PI; } static llvm::once_flag
InitializeLiveDebugValuesPassFlag; void llvm::initializeLiveDebugValuesPass
(PassRegistry &Registry) { llvm::call_once(InitializeLiveDebugValuesPassFlag
, initializeLiveDebugValuesPassOnce, std::ref(Registry)); }
338 false, false)static void *initializeLiveDebugValuesPassOnce(PassRegistry &
Registry) { PassInfo *PI = new PassInfo( "Live DEBUG_VALUE analysis"
, "livedebugvalues", &LiveDebugValues::ID, PassInfo::NormalCtor_t
(callDefaultCtor<LiveDebugValues>), false, false); Registry
.registerPass(*PI, true); return PI; } static llvm::once_flag
InitializeLiveDebugValuesPassFlag; void llvm::initializeLiveDebugValuesPass
(PassRegistry &Registry) { llvm::call_once(InitializeLiveDebugValuesPassFlag
, initializeLiveDebugValuesPassOnce, std::ref(Registry)); }
339
340/// Default construct and initialize the pass.
341LiveDebugValues::LiveDebugValues() : MachineFunctionPass(ID) {
342 initializeLiveDebugValuesPass(*PassRegistry::getPassRegistry());
343}
344
345/// Tell the pass manager which passes we depend on and what information we
346/// preserve.
347void LiveDebugValues::getAnalysisUsage(AnalysisUsage &AU) const {
348 AU.setPreservesCFG();
349 MachineFunctionPass::getAnalysisUsage(AU);
350}
351
352//===----------------------------------------------------------------------===//
353// Debug Range Extension Implementation
354//===----------------------------------------------------------------------===//
355
356#ifndef NDEBUG
357void LiveDebugValues::printVarLocInMBB(const MachineFunction &MF,
358 const VarLocInMBB &V,
359 const VarLocMap &VarLocIDs,
360 const char *msg,
361 raw_ostream &Out) const {
362 Out << '\n' << msg << '\n';
363 for (const MachineBasicBlock &BB : MF) {
364 const VarLocSet &L = V.lookup(&BB);
365 if (L.empty())
366 continue;
367 Out << "MBB: " << BB.getNumber() << ":\n";
368 for (unsigned VLL : L) {
369 const VarLoc &VL = VarLocIDs[VLL];
370 Out << " Var: " << VL.Var.getVar()->getName();
371 Out << " MI: ";
372 VL.dump();
373 }
374 }
375 Out << "\n";
376}
377#endif
378
379LiveDebugValues::VarLoc::SpillLoc
380LiveDebugValues::extractSpillBaseRegAndOffset(const MachineInstr &MI) {
381 assert(MI.hasOneMemOperand() &&((MI.hasOneMemOperand() && "Spill instruction does not have exactly one memory operand?"
) ? static_cast<void> (0) : __assert_fail ("MI.hasOneMemOperand() && \"Spill instruction does not have exactly one memory operand?\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 382, __PRETTY_FUNCTION__))
382 "Spill instruction does not have exactly one memory operand?")((MI.hasOneMemOperand() && "Spill instruction does not have exactly one memory operand?"
) ? static_cast<void> (0) : __assert_fail ("MI.hasOneMemOperand() && \"Spill instruction does not have exactly one memory operand?\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 382, __PRETTY_FUNCTION__));
383 auto MMOI = MI.memoperands_begin();
384 const PseudoSourceValue *PVal = (*MMOI)->getPseudoValue();
385 assert(PVal->kind() == PseudoSourceValue::FixedStack &&((PVal->kind() == PseudoSourceValue::FixedStack &&
"Inconsistent memory operand in spill instruction") ? static_cast
<void> (0) : __assert_fail ("PVal->kind() == PseudoSourceValue::FixedStack && \"Inconsistent memory operand in spill instruction\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 386, __PRETTY_FUNCTION__))
386 "Inconsistent memory operand in spill instruction")((PVal->kind() == PseudoSourceValue::FixedStack &&
"Inconsistent memory operand in spill instruction") ? static_cast
<void> (0) : __assert_fail ("PVal->kind() == PseudoSourceValue::FixedStack && \"Inconsistent memory operand in spill instruction\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 386, __PRETTY_FUNCTION__));
387 int FI = cast<FixedStackPseudoSourceValue>(PVal)->getFrameIndex();
388 const MachineBasicBlock *MBB = MI.getParent();
389 unsigned Reg;
390 int Offset = TFI->getFrameIndexReference(*MBB->getParent(), FI, Reg);
391 return {Reg, Offset};
392}
393
394/// End all previous ranges related to @MI and start a new range from @MI
395/// if it is a DBG_VALUE instr.
396void LiveDebugValues::transferDebugValue(const MachineInstr &MI,
397 OpenRangesSet &OpenRanges,
398 VarLocMap &VarLocIDs) {
399 if (!MI.isDebugValue())
400 return;
401 const DILocalVariable *Var = MI.getDebugVariable();
402 const DILocation *DebugLoc = MI.getDebugLoc();
403 const DILocation *InlinedAt = DebugLoc->getInlinedAt();
404 assert(Var->isValidLocationForIntrinsic(DebugLoc) &&((Var->isValidLocationForIntrinsic(DebugLoc) && "Expected inlined-at fields to agree"
) ? static_cast<void> (0) : __assert_fail ("Var->isValidLocationForIntrinsic(DebugLoc) && \"Expected inlined-at fields to agree\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 405, __PRETTY_FUNCTION__))
405 "Expected inlined-at fields to agree")((Var->isValidLocationForIntrinsic(DebugLoc) && "Expected inlined-at fields to agree"
) ? static_cast<void> (0) : __assert_fail ("Var->isValidLocationForIntrinsic(DebugLoc) && \"Expected inlined-at fields to agree\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 405, __PRETTY_FUNCTION__));
406
407 // End all previous ranges of Var.
408 DebugVariable V(Var, InlinedAt);
409 OpenRanges.erase(V);
410
411 // Add the VarLoc to OpenRanges from this DBG_VALUE.
412 // TODO: Currently handles DBG_VALUE which has only reg as location.
413 if (isDbgValueDescribedByReg(MI)) {
414 VarLoc VL(MI, LS);
415 unsigned ID = VarLocIDs.insert(VL);
416 OpenRanges.insert(ID, VL.Var);
417 }
418}
419
420/// Create new TransferDebugPair and insert it in \p Transfers. The VarLoc
421/// with \p OldVarID should be deleted form \p OpenRanges and replaced with
422/// new VarLoc. If \p NewReg is different than default zero value then the
423/// new location will be register location created by the copy like instruction,
424/// otherwise it is variable's location on the stack.
425void LiveDebugValues::insertTransferDebugPair(
426 MachineInstr &MI, OpenRangesSet &OpenRanges, TransferMap &Transfers,
427 VarLocMap &VarLocIDs, unsigned OldVarID, TransferKind Kind,
428 unsigned NewReg) {
429 const MachineInstr *DebugInstr = &VarLocIDs[OldVarID].MI;
430 MachineFunction *MF = MI.getParent()->getParent();
431 MachineInstr *NewDebugInstr;
432
433 auto ProcessVarLoc = [&MI, &OpenRanges, &Transfers, &DebugInstr,
434 &VarLocIDs](VarLoc &VL, MachineInstr *NewDebugInstr) {
435 unsigned LocId = VarLocIDs.insert(VL);
436
437 // Close this variable's previous location range.
438 DebugVariable V(DebugInstr->getDebugVariable(),
439 DebugInstr->getDebugLoc()->getInlinedAt());
440 OpenRanges.erase(V);
441
442 OpenRanges.insert(LocId, VL.Var);
443 // The newly created DBG_VALUE instruction NewDebugInstr must be inserted
444 // after MI. Keep track of the pairing.
445 TransferDebugPair MIP = {&MI, NewDebugInstr};
446 Transfers.push_back(MIP);
447 };
448
449 // End all previous ranges of Var.
450 OpenRanges.erase(VarLocIDs[OldVarID].Var);
451 switch (Kind) {
452 case TransferKind::TransferCopy: {
453 assert(NewReg &&((NewReg && "No register supplied when handling a copy of a debug value"
) ? static_cast<void> (0) : __assert_fail ("NewReg && \"No register supplied when handling a copy of a debug value\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 454, __PRETTY_FUNCTION__))
454 "No register supplied when handling a copy of a debug value")((NewReg && "No register supplied when handling a copy of a debug value"
) ? static_cast<void> (0) : __assert_fail ("NewReg && \"No register supplied when handling a copy of a debug value\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 454, __PRETTY_FUNCTION__));
455 // Create a DBG_VALUE instruction to describe the Var in its new
456 // register location.
457 NewDebugInstr = BuildMI(
458 *MF, DebugInstr->getDebugLoc(), DebugInstr->getDesc(),
459 DebugInstr->isIndirectDebugValue(), NewReg,
460 DebugInstr->getDebugVariable(), DebugInstr->getDebugExpression());
461 if (DebugInstr->isIndirectDebugValue())
462 NewDebugInstr->getOperand(1).setImm(DebugInstr->getOperand(1).getImm());
463 VarLoc VL(*NewDebugInstr, LS);
464 ProcessVarLoc(VL, NewDebugInstr);
465 LLVM_DEBUG(dbgs() << "Creating DBG_VALUE inst for register copy: ";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for register copy: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false)
466 NewDebugInstr->print(dbgs(), /*IsStandalone*/false,do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for register copy: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false)
467 /*SkipOpers*/false, /*SkipDebugLoc*/false,do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for register copy: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false)
468 /*AddNewLine*/true, TII))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for register copy: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false);
469 return;
470 }
471 case TransferKind::TransferSpill: {
472 // Create a DBG_VALUE instruction to describe the Var in its spilled
473 // location.
474 VarLoc::SpillLoc SpillLocation = extractSpillBaseRegAndOffset(MI);
475 auto *SpillExpr = DIExpression::prepend(DebugInstr->getDebugExpression(),
476 DIExpression::ApplyOffset,
477 SpillLocation.SpillOffset);
478 NewDebugInstr = BuildMI(
479 *MF, DebugInstr->getDebugLoc(), DebugInstr->getDesc(), true,
480 SpillLocation.SpillBase, DebugInstr->getDebugVariable(), SpillExpr);
481 VarLoc VL(*NewDebugInstr, SpillLocation.SpillBase,
482 SpillLocation.SpillOffset, LS);
483 ProcessVarLoc(VL, NewDebugInstr);
484 LLVM_DEBUG(dbgs() << "Creating DBG_VALUE inst for spill: ";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for spill: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false)
485 NewDebugInstr->print(dbgs(), /*IsStandalone*/false,do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for spill: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false)
486 /*SkipOpers*/false, /*SkipDebugLoc*/false,do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for spill: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false)
487 /*AddNewLine*/true, TII))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for spill: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false);
488 return;
489 }
490 case TransferKind::TransferRestore: {
491 assert(NewReg &&((NewReg && "No register supplied when handling a restore of a debug value"
) ? static_cast<void> (0) : __assert_fail ("NewReg && \"No register supplied when handling a restore of a debug value\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 492, __PRETTY_FUNCTION__))
492 "No register supplied when handling a restore of a debug value")((NewReg && "No register supplied when handling a restore of a debug value"
) ? static_cast<void> (0) : __assert_fail ("NewReg && \"No register supplied when handling a restore of a debug value\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 492, __PRETTY_FUNCTION__));
493 MachineFunction *MF = MI.getMF();
494 DIBuilder DIB(*const_cast<Function &>(MF->getFunction()).getParent());
495 NewDebugInstr =
496 BuildMI(*MF, DebugInstr->getDebugLoc(), DebugInstr->getDesc(), false,
497 NewReg, DebugInstr->getDebugVariable(), DIB.createExpression());
498 VarLoc VL(*NewDebugInstr, LS);
499 ProcessVarLoc(VL, NewDebugInstr);
500 LLVM_DEBUG(dbgs() << "Creating DBG_VALUE inst for register restore: ";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for register restore: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false)
501 NewDebugInstr->print(dbgs(), /*IsStandalone*/false,do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for register restore: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false)
502 /*SkipOpers*/false, /*SkipDebugLoc*/false,do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for register restore: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false)
503 /*AddNewLine*/true, TII))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Creating DBG_VALUE inst for register restore: "
; NewDebugInstr->print(dbgs(), false, false, false, true, TII
); } } while (false);
504 return;
505 }
506 }
507 llvm_unreachable("Invalid transfer kind")::llvm::llvm_unreachable_internal("Invalid transfer kind", "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 507);
508}
509
510/// A definition of a register may mark the end of a range.
511void LiveDebugValues::transferRegisterDef(MachineInstr &MI,
512 OpenRangesSet &OpenRanges,
513 const VarLocMap &VarLocIDs) {
514 MachineFunction *MF = MI.getMF();
515 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
516 unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
517 SparseBitVector<> KillSet;
518 for (const MachineOperand &MO : MI.operands()) {
519 // Determine whether the operand is a register def. Assume that call
520 // instructions never clobber SP, because some backends (e.g., AArch64)
521 // never list SP in the regmask.
522 if (MO.isReg() && MO.isDef() && MO.getReg() &&
523 TRI->isPhysicalRegister(MO.getReg()) &&
524 !(MI.isCall() && MO.getReg() == SP)) {
525 // Remove ranges of all aliased registers.
526 for (MCRegAliasIterator RAI(MO.getReg(), TRI, true); RAI.isValid(); ++RAI)
527 for (unsigned ID : OpenRanges.getVarLocs())
528 if (VarLocIDs[ID].isDescribedByReg() == *RAI)
529 KillSet.set(ID);
530 } else if (MO.isRegMask()) {
531 // Remove ranges of all clobbered registers. Register masks don't usually
532 // list SP as preserved. While the debug info may be off for an
533 // instruction or two around callee-cleanup calls, transferring the
534 // DEBUG_VALUE across the call is still a better user experience.
535 for (unsigned ID : OpenRanges.getVarLocs()) {
536 unsigned Reg = VarLocIDs[ID].isDescribedByReg();
537 if (Reg && Reg != SP && MO.clobbersPhysReg(Reg))
538 KillSet.set(ID);
539 }
540 }
541 }
542 OpenRanges.erase(KillSet, VarLocIDs);
543}
544
545/// Decide if @MI is a spill instruction and return true if it is. We use 2
546/// criteria to make this decision:
547/// - Is this instruction a store to a spill slot?
548/// - Is there a register operand that is both used and killed?
549/// TODO: Store optimization can fold spills into other stores (including
550/// other spills). We do not handle this yet (more than one memory operand).
551bool LiveDebugValues::isSpillInstruction(const MachineInstr &MI,
552 MachineFunction *MF, unsigned &Reg) {
553 SmallVector<const MachineMemOperand*, 1> Accesses;
554
555 // TODO: Handle multiple stores folded into one.
556 if (!MI.hasOneMemOperand())
557 return false;
558
559 if (!MI.getSpillSize(TII) && !MI.getFoldedSpillSize(TII))
560 return false; // This is not a spill instruction, since no valid size was
561 // returned from either function.
562
563 auto isKilledReg = [&](const MachineOperand MO, unsigned &Reg) {
564 if (!MO.isReg() || !MO.isUse()) {
565 Reg = 0;
566 return false;
567 }
568 Reg = MO.getReg();
569 return MO.isKill();
570 };
571
572 for (const MachineOperand &MO : MI.operands()) {
573 // In a spill instruction generated by the InlineSpiller the spilled
574 // register has its kill flag set.
575 if (isKilledReg(MO, Reg))
576 return true;
577 if (Reg != 0) {
578 // Check whether next instruction kills the spilled register.
579 // FIXME: Current solution does not cover search for killed register in
580 // bundles and instructions further down the chain.
581 auto NextI = std::next(MI.getIterator());
582 // Skip next instruction that points to basic block end iterator.
583 if (MI.getParent()->end() == NextI)
584 continue;
585 unsigned RegNext;
586 for (const MachineOperand &MONext : NextI->operands()) {
587 // Return true if we came across the register from the
588 // previous spill instruction that is killed in NextI.
589 if (isKilledReg(MONext, RegNext) && RegNext == Reg)
590 return true;
591 }
592 }
593 }
594 // Return false if we didn't find spilled register.
595 return false;
596}
597
598Optional<LiveDebugValues::VarLoc::SpillLoc>
599LiveDebugValues::isRestoreInstruction(const MachineInstr &MI,
600 MachineFunction *MF, unsigned &Reg) {
601 if (!MI.hasOneMemOperand())
602 return None;
603
604 // FIXME: Handle folded restore instructions with more than one memory
605 // operand.
606 if (MI.getRestoreSize(TII)) {
607 Reg = MI.getOperand(0).getReg();
608 return extractSpillBaseRegAndOffset(MI);
609 }
610 return None;
611}
612
613/// A spilled register may indicate that we have to end the current range of
614/// a variable and create a new one for the spill location.
615/// A restored register may indicate the reverse situation.
616/// We don't want to insert any instructions in process(), so we just create
617/// the DBG_VALUE without inserting it and keep track of it in \p Transfers.
618/// It will be inserted into the BB when we're done iterating over the
619/// instructions.
620void LiveDebugValues::transferSpillOrRestoreInst(MachineInstr &MI,
621 OpenRangesSet &OpenRanges,
622 VarLocMap &VarLocIDs,
623 TransferMap &Transfers) {
624 MachineFunction *MF = MI.getMF();
625 TransferKind TKind;
626 unsigned Reg;
627 Optional<VarLoc::SpillLoc> Loc;
628
629 LLVM_DEBUG(dbgs() << "Examining instruction: "; MI.dump();)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Examining instruction: "
; MI.dump();; } } while (false);
630
631 if (isSpillInstruction(MI, MF, Reg)) {
632 TKind = TransferKind::TransferSpill;
633 LLVM_DEBUG(dbgs() << "Recognized as spill: "; MI.dump();)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Recognized as spill: "
; MI.dump();; } } while (false);
634 LLVM_DEBUG(dbgs() << "Register: " << Reg << " " << printReg(Reg, TRI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Register: " << Reg
<< " " << printReg(Reg, TRI) << "\n"; } } while
(false)
635 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Register: " << Reg
<< " " << printReg(Reg, TRI) << "\n"; } } while
(false);
636 } else {
637 if (!(Loc = isRestoreInstruction(MI, MF, Reg)))
638 return;
639 TKind = TransferKind::TransferRestore;
640 LLVM_DEBUG(dbgs() << "Recognized as restore: "; MI.dump();)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Recognized as restore: "
; MI.dump();; } } while (false);
641 LLVM_DEBUG(dbgs() << "Register: " << Reg << " " << printReg(Reg, TRI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Register: " << Reg
<< " " << printReg(Reg, TRI) << "\n"; } } while
(false)
642 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Register: " << Reg
<< " " << printReg(Reg, TRI) << "\n"; } } while
(false);
643 }
644 // Check if the register or spill location is the location of a debug value.
645 for (unsigned ID : OpenRanges.getVarLocs()) {
646 if (TKind == TransferKind::TransferSpill &&
647 VarLocIDs[ID].isDescribedByReg() == Reg) {
648 LLVM_DEBUG(dbgs() << "Spilling Register " << printReg(Reg, TRI) << '('do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Spilling Register " <<
printReg(Reg, TRI) << '(' << VarLocIDs[ID].Var.getVar
()->getName() << ")\n"; } } while (false)
649 << VarLocIDs[ID].Var.getVar()->getName() << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Spilling Register " <<
printReg(Reg, TRI) << '(' << VarLocIDs[ID].Var.getVar
()->getName() << ")\n"; } } while (false);
650 } else if (TKind == TransferKind::TransferRestore &&
651 VarLocIDs[ID].Loc.SpillLocation == *Loc) {
652 LLVM_DEBUG(dbgs() << "Restoring Register " << printReg(Reg, TRI) << '('do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Restoring Register " <<
printReg(Reg, TRI) << '(' << VarLocIDs[ID].Var.getVar
()->getName() << ")\n"; } } while (false)
653 << VarLocIDs[ID].Var.getVar()->getName() << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Restoring Register " <<
printReg(Reg, TRI) << '(' << VarLocIDs[ID].Var.getVar
()->getName() << ")\n"; } } while (false);
654 } else
655 continue;
656 insertTransferDebugPair(MI, OpenRanges, Transfers, VarLocIDs, ID, TKind,
657 Reg);
658 return;
659 }
660}
661
662/// If \p MI is a register copy instruction, that copies a previously tracked
663/// value from one register to another register that is callee saved, we
664/// create new DBG_VALUE instruction described with copy destination register.
665void LiveDebugValues::transferRegisterCopy(MachineInstr &MI,
666 OpenRangesSet &OpenRanges,
667 VarLocMap &VarLocIDs,
668 TransferMap &Transfers) {
669 const MachineOperand *SrcRegOp, *DestRegOp;
670
671 if (!TII->isCopyInstr(MI, SrcRegOp, DestRegOp) || !SrcRegOp->isKill() ||
672 !DestRegOp->isDef())
673 return;
674
675 auto isCalleSavedReg = [&](unsigned Reg) {
676 for (MCRegAliasIterator RAI(Reg, TRI, true); RAI.isValid(); ++RAI)
677 if (CalleeSavedRegs.test(*RAI))
678 return true;
679 return false;
680 };
681
682 unsigned SrcReg = SrcRegOp->getReg();
683 unsigned DestReg = DestRegOp->getReg();
684
685 // We want to recognize instructions where destination register is callee
686 // saved register. If register that could be clobbered by the call is
687 // included, there would be a great chance that it is going to be clobbered
688 // soon. It is more likely that previous register location, which is callee
689 // saved, is going to stay unclobbered longer, even if it is killed.
690 if (!isCalleSavedReg(DestReg))
691 return;
692
693 for (unsigned ID : OpenRanges.getVarLocs()) {
694 if (VarLocIDs[ID].isDescribedByReg() == SrcReg) {
695 insertTransferDebugPair(MI, OpenRanges, Transfers, VarLocIDs, ID,
696 TransferKind::TransferCopy, DestReg);
697 return;
698 }
699 }
700}
701
702/// Terminate all open ranges at the end of the current basic block.
703bool LiveDebugValues::transferTerminatorInst(MachineInstr &MI,
704 OpenRangesSet &OpenRanges,
705 VarLocInMBB &OutLocs,
706 const VarLocMap &VarLocIDs) {
707 bool Changed = false;
708 const MachineBasicBlock *CurMBB = MI.getParent();
709 if (!(MI.isTerminator() || (&MI == &CurMBB->back())))
710 return false;
711
712 if (OpenRanges.empty())
713 return false;
714
715 LLVM_DEBUG(for (unsigned IDdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { for (unsigned ID : OpenRanges.getVarLocs
()) { dbgs() << "Add to OutLocs in MBB #" << CurMBB
->getNumber() << ": "; VarLocIDs[ID].dump(); }; } }
while (false)
716 : OpenRanges.getVarLocs()) {do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { for (unsigned ID : OpenRanges.getVarLocs
()) { dbgs() << "Add to OutLocs in MBB #" << CurMBB
->getNumber() << ": "; VarLocIDs[ID].dump(); }; } }
while (false)
717 // Copy OpenRanges to OutLocs, if not already present.do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { for (unsigned ID : OpenRanges.getVarLocs
()) { dbgs() << "Add to OutLocs in MBB #" << CurMBB
->getNumber() << ": "; VarLocIDs[ID].dump(); }; } }
while (false)
718 dbgs() << "Add to OutLocs in MBB #" << CurMBB->getNumber() << ": ";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { for (unsigned ID : OpenRanges.getVarLocs
()) { dbgs() << "Add to OutLocs in MBB #" << CurMBB
->getNumber() << ": "; VarLocIDs[ID].dump(); }; } }
while (false)
719 VarLocIDs[ID].dump();do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { for (unsigned ID : OpenRanges.getVarLocs
()) { dbgs() << "Add to OutLocs in MBB #" << CurMBB
->getNumber() << ": "; VarLocIDs[ID].dump(); }; } }
while (false)
720 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { for (unsigned ID : OpenRanges.getVarLocs
()) { dbgs() << "Add to OutLocs in MBB #" << CurMBB
->getNumber() << ": "; VarLocIDs[ID].dump(); }; } }
while (false);
721 VarLocSet &VLS = OutLocs[CurMBB];
722 Changed = VLS |= OpenRanges.getVarLocs();
723 // New OutLocs set may be different due to spill, restore or register
724 // copy instruction processing.
725 if (Changed)
726 VLS = OpenRanges.getVarLocs();
727 OpenRanges.clear();
728 return Changed;
729}
730
731/// This routine creates OpenRanges and OutLocs.
732bool LiveDebugValues::process(MachineInstr &MI, OpenRangesSet &OpenRanges,
733 VarLocInMBB &OutLocs, VarLocMap &VarLocIDs,
734 TransferMap &Transfers, bool transferChanges) {
735 bool Changed = false;
736 transferDebugValue(MI, OpenRanges, VarLocIDs);
737 transferRegisterDef(MI, OpenRanges, VarLocIDs);
738 if (transferChanges) {
739 transferRegisterCopy(MI, OpenRanges, VarLocIDs, Transfers);
740 transferSpillOrRestoreInst(MI, OpenRanges, VarLocIDs, Transfers);
741 }
742 Changed = transferTerminatorInst(MI, OpenRanges, OutLocs, VarLocIDs);
743 return Changed;
744}
745
746/// This routine joins the analysis results of all incoming edges in @MBB by
747/// inserting a new DBG_VALUE instruction at the start of the @MBB - if the same
748/// source variable in all the predecessors of @MBB reside in the same location.
749bool LiveDebugValues::join(
750 MachineBasicBlock &MBB, VarLocInMBB &OutLocs, VarLocInMBB &InLocs,
751 const VarLocMap &VarLocIDs,
752 SmallPtrSet<const MachineBasicBlock *, 16> &Visited,
753 SmallPtrSetImpl<const MachineBasicBlock *> &ArtificialBlocks) {
754 LLVM_DEBUG(dbgs() << "join MBB: " << MBB.getNumber() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "join MBB: " << MBB
.getNumber() << "\n"; } } while (false);
755 bool Changed = false;
756
757 VarLocSet InLocsT; // Temporary incoming locations.
758
759 // For all predecessors of this MBB, find the set of VarLocs that
760 // can be joined.
761 int NumVisited = 0;
762 for (auto p : MBB.predecessors()) {
763 // Ignore unvisited predecessor blocks. As we are processing
764 // the blocks in reverse post-order any unvisited block can
765 // be considered to not remove any incoming values.
766 if (!Visited.count(p)) {
767 LLVM_DEBUG(dbgs() << " ignoring unvisited pred MBB: " << p->getNumber()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << " ignoring unvisited pred MBB: "
<< p->getNumber() << "\n"; } } while (false)
768 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << " ignoring unvisited pred MBB: "
<< p->getNumber() << "\n"; } } while (false);
769 continue;
770 }
771 auto OL = OutLocs.find(p);
772 // Join is null in case of empty OutLocs from any of the pred.
773 if (OL == OutLocs.end())
774 return false;
775
776 // Just copy over the Out locs to incoming locs for the first visited
777 // predecessor, and for all other predecessors join the Out locs.
778 if (!NumVisited)
779 InLocsT = OL->second;
780 else
781 InLocsT &= OL->second;
782
783 LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { if (!InLocsT.empty()) { for (auto ID
: InLocsT) dbgs() << " gathered candidate incoming var: "
<< VarLocIDs[ID].Var.getVar()->getName() << "\n"
; } }; } } while (false)
784 if (!InLocsT.empty()) {do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { if (!InLocsT.empty()) { for (auto ID
: InLocsT) dbgs() << " gathered candidate incoming var: "
<< VarLocIDs[ID].Var.getVar()->getName() << "\n"
; } }; } } while (false)
785 for (auto ID : InLocsT)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { if (!InLocsT.empty()) { for (auto ID
: InLocsT) dbgs() << " gathered candidate incoming var: "
<< VarLocIDs[ID].Var.getVar()->getName() << "\n"
; } }; } } while (false)
786 dbgs() << " gathered candidate incoming var: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { if (!InLocsT.empty()) { for (auto ID
: InLocsT) dbgs() << " gathered candidate incoming var: "
<< VarLocIDs[ID].Var.getVar()->getName() << "\n"
; } }; } } while (false)
787 << VarLocIDs[ID].Var.getVar()->getName() << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { if (!InLocsT.empty()) { for (auto ID
: InLocsT) dbgs() << " gathered candidate incoming var: "
<< VarLocIDs[ID].Var.getVar()->getName() << "\n"
; } }; } } while (false)
788 }do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { if (!InLocsT.empty()) { for (auto ID
: InLocsT) dbgs() << " gathered candidate incoming var: "
<< VarLocIDs[ID].Var.getVar()->getName() << "\n"
; } }; } } while (false)
789 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { if (!InLocsT.empty()) { for (auto ID
: InLocsT) dbgs() << " gathered candidate incoming var: "
<< VarLocIDs[ID].Var.getVar()->getName() << "\n"
; } }; } } while (false);
790
791 NumVisited++;
792 }
793
794 // Filter out DBG_VALUES that are out of scope.
795 VarLocSet KillSet;
796 bool IsArtificial = ArtificialBlocks.count(&MBB);
797 if (!IsArtificial) {
798 for (auto ID : InLocsT) {
799 if (!VarLocIDs[ID].dominates(MBB)) {
800 KillSet.set(ID);
801 LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { auto Name = VarLocIDs[ID].Var.getVar
()->getName(); dbgs() << " killing " << Name <<
", it doesn't dominate MBB\n"; }; } } while (false)
802 auto Name = VarLocIDs[ID].Var.getVar()->getName();do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { auto Name = VarLocIDs[ID].Var.getVar
()->getName(); dbgs() << " killing " << Name <<
", it doesn't dominate MBB\n"; }; } } while (false)
803 dbgs() << " killing " << Name << ", it doesn't dominate MBB\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { auto Name = VarLocIDs[ID].Var.getVar
()->getName(); dbgs() << " killing " << Name <<
", it doesn't dominate MBB\n"; }; } } while (false)
804 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { { auto Name = VarLocIDs[ID].Var.getVar
()->getName(); dbgs() << " killing " << Name <<
", it doesn't dominate MBB\n"; }; } } while (false);
805 }
806 }
807 }
808 InLocsT.intersectWithComplement(KillSet);
809
810 // As we are processing blocks in reverse post-order we
811 // should have processed at least one predecessor, unless it
812 // is the entry block which has no predecessor.
813 assert((NumVisited || MBB.pred_empty()) &&(((NumVisited || MBB.pred_empty()) && "Should have processed at least one predecessor"
) ? static_cast<void> (0) : __assert_fail ("(NumVisited || MBB.pred_empty()) && \"Should have processed at least one predecessor\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 814, __PRETTY_FUNCTION__))
814 "Should have processed at least one predecessor")(((NumVisited || MBB.pred_empty()) && "Should have processed at least one predecessor"
) ? static_cast<void> (0) : __assert_fail ("(NumVisited || MBB.pred_empty()) && \"Should have processed at least one predecessor\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 814, __PRETTY_FUNCTION__));
815 if (InLocsT.empty())
816 return false;
817
818 VarLocSet &ILS = InLocs[&MBB];
819
820 // Insert DBG_VALUE instructions, if not already inserted.
821 VarLocSet Diff = InLocsT;
822 Diff.intersectWithComplement(ILS);
823 for (auto ID : Diff) {
824 // This VarLoc is not found in InLocs i.e. it is not yet inserted. So, a
825 // new range is started for the var from the mbb's beginning by inserting
826 // a new DBG_VALUE. process() will end this range however appropriate.
827 const VarLoc &DiffIt = VarLocIDs[ID];
828 const MachineInstr *DebugInstr = &DiffIt.MI;
829 MachineInstr *MI = BuildMI(
830 MBB, MBB.instr_begin(), DebugInstr->getDebugLoc(),
831 DebugInstr->getDesc(), DebugInstr->isIndirectDebugValue(),
832 DebugInstr->getOperand(0).getReg(), DebugInstr->getDebugVariable(),
833 DebugInstr->getDebugExpression());
834 if (DebugInstr->isIndirectDebugValue())
835 MI->getOperand(1).setImm(DebugInstr->getOperand(1).getImm());
836 LLVM_DEBUG(dbgs() << "Inserted: "; MI->dump();)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Inserted: "; MI->dump
();; } } while (false);
837 ILS.set(ID);
838 ++NumInserted;
839 Changed = true;
840 }
841 return Changed;
842}
843
844/// Calculate the liveness information for the given machine function and
845/// extend ranges across basic blocks.
846bool LiveDebugValues::ExtendRanges(MachineFunction &MF) {
847 LLVM_DEBUG(dbgs() << "\nDebug Range Extension\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "\nDebug Range Extension\n"
; } } while (false);
848
849 bool Changed = false;
850 bool OLChanged = false;
851 bool MBBJoined = false;
852
853 VarLocMap VarLocIDs; // Map VarLoc<>unique ID for use in bitvectors.
854 OpenRangesSet OpenRanges; // Ranges that are open until end of bb.
855 VarLocInMBB OutLocs; // Ranges that exist beyond bb.
856 VarLocInMBB InLocs; // Ranges that are incoming after joining.
857 TransferMap Transfers; // DBG_VALUEs associated with spills.
858
859 // Blocks which are artificial, i.e. blocks which exclusively contain
860 // instructions without locations, or with line 0 locations.
861 SmallPtrSet<const MachineBasicBlock *, 16> ArtificialBlocks;
862
863 DenseMap<unsigned int, MachineBasicBlock *> OrderToBB;
864 DenseMap<MachineBasicBlock *, unsigned int> BBToOrder;
865 std::priority_queue<unsigned int, std::vector<unsigned int>,
866 std::greater<unsigned int>>
867 Worklist;
868 std::priority_queue<unsigned int, std::vector<unsigned int>,
869 std::greater<unsigned int>>
870 Pending;
871
872 enum : bool { dontTransferChanges = false, transferChanges = true };
873
874 // Initialize every mbb with OutLocs.
875 // We are not looking at any spill instructions during the initial pass
876 // over the BBs. The LiveDebugVariables pass has already created DBG_VALUE
877 // instructions for spills of registers that are known to be user variables
878 // within the BB in which the spill occurs.
879 for (auto &MBB : MF)
880 for (auto &MI : MBB)
881 process(MI, OpenRanges, OutLocs, VarLocIDs, Transfers,
882 dontTransferChanges);
883
884 auto hasNonArtificialLocation = [](const MachineInstr &MI) -> bool {
885 if (const DebugLoc &DL = MI.getDebugLoc())
886 return DL.getLine() != 0;
887 return false;
888 };
889 for (auto &MBB : MF)
890 if (none_of(MBB.instrs(), hasNonArtificialLocation))
891 ArtificialBlocks.insert(&MBB);
892
893 LLVM_DEBUG(printVarLocInMBB(MF, OutLocs, VarLocIDs,do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { printVarLocInMBB(MF, OutLocs, VarLocIDs
, "OutLocs after initialization", dbgs()); } } while (false)
894 "OutLocs after initialization", dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { printVarLocInMBB(MF, OutLocs, VarLocIDs
, "OutLocs after initialization", dbgs()); } } while (false);
895
896 ReversePostOrderTraversal<MachineFunction *> RPOT(&MF);
897 unsigned int RPONumber = 0;
898 for (auto RI = RPOT.begin(), RE = RPOT.end(); RI != RE; ++RI) {
899 OrderToBB[RPONumber] = *RI;
900 BBToOrder[*RI] = RPONumber;
901 Worklist.push(RPONumber);
902 ++RPONumber;
903 }
904 // This is a standard "union of predecessor outs" dataflow problem.
905 // To solve it, we perform join() and process() using the two worklist method
906 // until the ranges converge.
907 // Ranges have converged when both worklists are empty.
908 SmallPtrSet<const MachineBasicBlock *, 16> Visited;
909 while (!Worklist.empty() || !Pending.empty()) {
910 // We track what is on the pending worklist to avoid inserting the same
911 // thing twice. We could avoid this with a custom priority queue, but this
912 // is probably not worth it.
913 SmallPtrSet<MachineBasicBlock *, 16> OnPending;
914 LLVM_DEBUG(dbgs() << "Processing Worklist\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { dbgs() << "Processing Worklist\n"
; } } while (false);
915 while (!Worklist.empty()) {
916 MachineBasicBlock *MBB = OrderToBB[Worklist.top()];
917 Worklist.pop();
918 MBBJoined =
919 join(*MBB, OutLocs, InLocs, VarLocIDs, Visited, ArtificialBlocks);
920 Visited.insert(MBB);
921 if (MBBJoined) {
922 MBBJoined = false;
Value stored to 'MBBJoined' is never read
923 Changed = true;
924 // Now that we have started to extend ranges across BBs we need to
925 // examine spill instructions to see whether they spill registers that
926 // correspond to user variables.
927 for (auto &MI : *MBB)
928 OLChanged |= process(MI, OpenRanges, OutLocs, VarLocIDs, Transfers,
929 transferChanges);
930
931 // Add any DBG_VALUE instructions necessitated by spills.
932 for (auto &TR : Transfers)
933 MBB->insertAfter(MachineBasicBlock::iterator(*TR.TransferInst),
934 TR.DebugInst);
935 Transfers.clear();
936
937 LLVM_DEBUG(printVarLocInMBB(MF, OutLocs, VarLocIDs,do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { printVarLocInMBB(MF, OutLocs, VarLocIDs
, "OutLocs after propagating", dbgs()); } } while (false)
938 "OutLocs after propagating", dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { printVarLocInMBB(MF, OutLocs, VarLocIDs
, "OutLocs after propagating", dbgs()); } } while (false);
939 LLVM_DEBUG(printVarLocInMBB(MF, InLocs, VarLocIDs,do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { printVarLocInMBB(MF, InLocs, VarLocIDs
, "InLocs after propagating", dbgs()); } } while (false)
940 "InLocs after propagating", dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { printVarLocInMBB(MF, InLocs, VarLocIDs
, "InLocs after propagating", dbgs()); } } while (false);
941
942 if (OLChanged) {
943 OLChanged = false;
944 for (auto s : MBB->successors())
945 if (OnPending.insert(s).second) {
946 Pending.push(BBToOrder[s]);
947 }
948 }
949 }
950 }
951 Worklist.swap(Pending);
952 // At this point, pending must be empty, since it was just the empty
953 // worklist
954 assert(Pending.empty() && "Pending should be empty")((Pending.empty() && "Pending should be empty") ? static_cast
<void> (0) : __assert_fail ("Pending.empty() && \"Pending should be empty\""
, "/build/llvm-toolchain-snapshot-9~svn362543/lib/CodeGen/LiveDebugValues.cpp"
, 954, __PRETTY_FUNCTION__));
955 }
956
957 LLVM_DEBUG(printVarLocInMBB(MF, OutLocs, VarLocIDs, "Final OutLocs", dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { printVarLocInMBB(MF, OutLocs, VarLocIDs
, "Final OutLocs", dbgs()); } } while (false);
958 LLVM_DEBUG(printVarLocInMBB(MF, InLocs, VarLocIDs, "Final InLocs", dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvalues")) { printVarLocInMBB(MF, InLocs, VarLocIDs
, "Final InLocs", dbgs()); } } while (false);
959 return Changed;
960}
961
962bool LiveDebugValues::runOnMachineFunction(MachineFunction &MF) {
963 if (!MF.getFunction().getSubprogram())
964 // LiveDebugValues will already have removed all DBG_VALUEs.
965 return false;
966
967 // Skip functions from NoDebug compilation units.
968 if (MF.getFunction().getSubprogram()->getUnit()->getEmissionKind() ==
969 DICompileUnit::NoDebug)
970 return false;
971
972 TRI = MF.getSubtarget().getRegisterInfo();
973 TII = MF.getSubtarget().getInstrInfo();
974 TFI = MF.getSubtarget().getFrameLowering();
975 TFI->determineCalleeSaves(MF, CalleeSavedRegs,
976 make_unique<RegScavenger>().get());
977 LS.initialize(MF);
978
979 bool Changed = ExtendRanges(MF);
980 return Changed;
981}