Bug Summary

File:lib/CodeGen/LiveDebugVariables.cpp
Warning:line 660, column 5
Value stored to 'ToEnd' 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 LiveDebugVariables.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-8/lib/clang/8.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen -I /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/include -I /build/llvm-toolchain-snapshot-8~svn350071/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/8.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-8/lib/clang/8.0.0/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-8~svn350071/build-llvm/lib/CodeGen -fdebug-prefix-map=/build/llvm-toolchain-snapshot-8~svn350071=. -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-2018-12-27-042839-1215-1 -x c++ /build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp -faddrsig
1//===- LiveDebugVariables.cpp - Tracking debug info variables -------------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the LiveDebugVariables analysis.
11//
12// Remove all DBG_VALUE instructions referencing virtual registers and replace
13// them with a data structure tracking where live user variables are kept - in a
14// virtual register or in a stack slot.
15//
16// Allow the data structure to be updated during register allocation when values
17// are moved between registers and stack slots. Finally emit new DBG_VALUE
18// instructions after register allocation is complete.
19//
20//===----------------------------------------------------------------------===//
21
22#include "LiveDebugVariables.h"
23#include "llvm/ADT/ArrayRef.h"
24#include "llvm/ADT/DenseMap.h"
25#include "llvm/ADT/IntervalMap.h"
26#include "llvm/ADT/STLExtras.h"
27#include "llvm/ADT/SmallSet.h"
28#include "llvm/ADT/SmallVector.h"
29#include "llvm/ADT/Statistic.h"
30#include "llvm/ADT/StringRef.h"
31#include "llvm/CodeGen/LexicalScopes.h"
32#include "llvm/CodeGen/LiveInterval.h"
33#include "llvm/CodeGen/LiveIntervals.h"
34#include "llvm/CodeGen/MachineBasicBlock.h"
35#include "llvm/CodeGen/MachineDominators.h"
36#include "llvm/CodeGen/MachineFunction.h"
37#include "llvm/CodeGen/MachineInstr.h"
38#include "llvm/CodeGen/MachineInstrBuilder.h"
39#include "llvm/CodeGen/MachineOperand.h"
40#include "llvm/CodeGen/MachineRegisterInfo.h"
41#include "llvm/CodeGen/SlotIndexes.h"
42#include "llvm/CodeGen/TargetInstrInfo.h"
43#include "llvm/CodeGen/TargetOpcodes.h"
44#include "llvm/CodeGen/TargetRegisterInfo.h"
45#include "llvm/CodeGen/TargetSubtargetInfo.h"
46#include "llvm/CodeGen/VirtRegMap.h"
47#include "llvm/Config/llvm-config.h"
48#include "llvm/IR/DebugInfoMetadata.h"
49#include "llvm/IR/DebugLoc.h"
50#include "llvm/IR/Function.h"
51#include "llvm/IR/Metadata.h"
52#include "llvm/MC/MCRegisterInfo.h"
53#include "llvm/Pass.h"
54#include "llvm/Support/Casting.h"
55#include "llvm/Support/CommandLine.h"
56#include "llvm/Support/Compiler.h"
57#include "llvm/Support/Debug.h"
58#include "llvm/Support/raw_ostream.h"
59#include <algorithm>
60#include <cassert>
61#include <iterator>
62#include <memory>
63#include <utility>
64
65using namespace llvm;
66
67#define DEBUG_TYPE"livedebugvars" "livedebugvars"
68
69static cl::opt<bool>
70EnableLDV("live-debug-variables", cl::init(true),
71 cl::desc("Enable the live debug variables pass"), cl::Hidden);
72
73STATISTIC(NumInsertedDebugValues, "Number of DBG_VALUEs inserted")static llvm::Statistic NumInsertedDebugValues = {"livedebugvars"
, "NumInsertedDebugValues", "Number of DBG_VALUEs inserted", {
0}, {false}}
;
74
75char LiveDebugVariables::ID = 0;
76
77INITIALIZE_PASS_BEGIN(LiveDebugVariables, DEBUG_TYPE,static void *initializeLiveDebugVariablesPassOnce(PassRegistry
&Registry) {
78 "Debug Variable Analysis", false, false)static void *initializeLiveDebugVariablesPassOnce(PassRegistry
&Registry) {
79INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)initializeMachineDominatorTreePass(Registry);
80INITIALIZE_PASS_DEPENDENCY(LiveIntervals)initializeLiveIntervalsPass(Registry);
81INITIALIZE_PASS_END(LiveDebugVariables, DEBUG_TYPE,PassInfo *PI = new PassInfo( "Debug Variable Analysis", "livedebugvars"
, &LiveDebugVariables::ID, PassInfo::NormalCtor_t(callDefaultCtor
<LiveDebugVariables>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeLiveDebugVariablesPassFlag
; void llvm::initializeLiveDebugVariablesPass(PassRegistry &
Registry) { llvm::call_once(InitializeLiveDebugVariablesPassFlag
, initializeLiveDebugVariablesPassOnce, std::ref(Registry)); }
82 "Debug Variable Analysis", false, false)PassInfo *PI = new PassInfo( "Debug Variable Analysis", "livedebugvars"
, &LiveDebugVariables::ID, PassInfo::NormalCtor_t(callDefaultCtor
<LiveDebugVariables>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeLiveDebugVariablesPassFlag
; void llvm::initializeLiveDebugVariablesPass(PassRegistry &
Registry) { llvm::call_once(InitializeLiveDebugVariablesPassFlag
, initializeLiveDebugVariablesPassOnce, std::ref(Registry)); }
83
84void LiveDebugVariables::getAnalysisUsage(AnalysisUsage &AU) const {
85 AU.addRequired<MachineDominatorTree>();
86 AU.addRequiredTransitive<LiveIntervals>();
87 AU.setPreservesAll();
88 MachineFunctionPass::getAnalysisUsage(AU);
89}
90
91LiveDebugVariables::LiveDebugVariables() : MachineFunctionPass(ID) {
92 initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
93}
94
95enum : unsigned { UndefLocNo = ~0U };
96
97/// Describes a location by number along with some flags about the original
98/// usage of the location.
99class DbgValueLocation {
100public:
101 DbgValueLocation(unsigned LocNo, bool WasIndirect)
102 : LocNo(LocNo), WasIndirect(WasIndirect) {
103 static_assert(sizeof(*this) == sizeof(unsigned), "bad bitfield packing");
104 assert(locNo() == LocNo && "location truncation")((locNo() == LocNo && "location truncation") ? static_cast
<void> (0) : __assert_fail ("locNo() == LocNo && \"location truncation\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 104, __PRETTY_FUNCTION__))
;
105 }
106
107 DbgValueLocation() : LocNo(0), WasIndirect(0) {}
108
109 unsigned locNo() const {
110 // Fix up the undef location number, which gets truncated.
111 return LocNo == INT_MAX2147483647 ? UndefLocNo : LocNo;
112 }
113 bool wasIndirect() const { return WasIndirect; }
114 bool isUndef() const { return locNo() == UndefLocNo; }
115
116 DbgValueLocation changeLocNo(unsigned NewLocNo) const {
117 return DbgValueLocation(NewLocNo, WasIndirect);
118 }
119
120 friend inline bool operator==(const DbgValueLocation &LHS,
121 const DbgValueLocation &RHS) {
122 return LHS.LocNo == RHS.LocNo && LHS.WasIndirect == RHS.WasIndirect;
123 }
124
125 friend inline bool operator!=(const DbgValueLocation &LHS,
126 const DbgValueLocation &RHS) {
127 return !(LHS == RHS);
128 }
129
130private:
131 unsigned LocNo : 31;
132 unsigned WasIndirect : 1;
133};
134
135/// Map of where a user value is live, and its location.
136using LocMap = IntervalMap<SlotIndex, DbgValueLocation, 4>;
137
138/// Map of stack slot offsets for spilled locations.
139/// Non-spilled locations are not added to the map.
140using SpillOffsetMap = DenseMap<unsigned, unsigned>;
141
142namespace {
143
144class LDVImpl;
145
146/// A user value is a part of a debug info user variable.
147///
148/// A DBG_VALUE instruction notes that (a sub-register of) a virtual register
149/// holds part of a user variable. The part is identified by a byte offset.
150///
151/// UserValues are grouped into equivalence classes for easier searching. Two
152/// user values are related if they refer to the same variable, or if they are
153/// held by the same virtual register. The equivalence class is the transitive
154/// closure of that relation.
155class UserValue {
156 const DILocalVariable *Variable; ///< The debug info variable we are part of.
157 const DIExpression *Expression; ///< Any complex address expression.
158 DebugLoc dl; ///< The debug location for the variable. This is
159 ///< used by dwarf writer to find lexical scope.
160 UserValue *leader; ///< Equivalence class leader.
161 UserValue *next = nullptr; ///< Next value in equivalence class, or null.
162
163 /// Numbered locations referenced by locmap.
164 SmallVector<MachineOperand, 4> locations;
165
166 /// Map of slot indices where this value is live.
167 LocMap locInts;
168
169 /// Set of interval start indexes that have been trimmed to the
170 /// lexical scope.
171 SmallSet<SlotIndex, 2> trimmedDefs;
172
173 /// Insert a DBG_VALUE into MBB at Idx for LocNo.
174 void insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
175 SlotIndex StopIdx, DbgValueLocation Loc, bool Spilled,
176 unsigned SpillOffset, LiveIntervals &LIS,
177 const TargetInstrInfo &TII,
178 const TargetRegisterInfo &TRI);
179
180 /// Replace OldLocNo ranges with NewRegs ranges where NewRegs
181 /// is live. Returns true if any changes were made.
182 bool splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
183 LiveIntervals &LIS);
184
185public:
186 /// Create a new UserValue.
187 UserValue(const DILocalVariable *var, const DIExpression *expr, DebugLoc L,
188 LocMap::Allocator &alloc)
189 : Variable(var), Expression(expr), dl(std::move(L)), leader(this),
190 locInts(alloc) {}
191
192 /// Get the leader of this value's equivalence class.
193 UserValue *getLeader() {
194 UserValue *l = leader;
195 while (l != l->leader)
196 l = l->leader;
197 return leader = l;
198 }
199
200 /// Return the next UserValue in the equivalence class.
201 UserValue *getNext() const { return next; }
202
203 /// Does this UserValue match the parameters?
204 bool match(const DILocalVariable *Var, const DIExpression *Expr,
205 const DILocation *IA) const {
206 // FIXME: The fragment should be part of the equivalence class, but not
207 // other things in the expression like stack values.
208 return Var == Variable && Expr == Expression && dl->getInlinedAt() == IA;
209 }
210
211 /// Merge equivalence classes.
212 static UserValue *merge(UserValue *L1, UserValue *L2) {
213 L2 = L2->getLeader();
214 if (!L1)
215 return L2;
216 L1 = L1->getLeader();
217 if (L1 == L2)
218 return L1;
219 // Splice L2 before L1's members.
220 UserValue *End = L2;
221 while (End->next) {
222 End->leader = L1;
223 End = End->next;
224 }
225 End->leader = L1;
226 End->next = L1->next;
227 L1->next = L2;
228 return L1;
229 }
230
231 /// Return the location number that matches Loc.
232 ///
233 /// For undef values we always return location number UndefLocNo without
234 /// inserting anything in locations. Since locations is a vector and the
235 /// location number is the position in the vector and UndefLocNo is ~0,
236 /// we would need a very big vector to put the value at the right position.
237 unsigned getLocationNo(const MachineOperand &LocMO) {
238 if (LocMO.isReg()) {
239 if (LocMO.getReg() == 0)
240 return UndefLocNo;
241 // For register locations we dont care about use/def and other flags.
242 for (unsigned i = 0, e = locations.size(); i != e; ++i)
243 if (locations[i].isReg() &&
244 locations[i].getReg() == LocMO.getReg() &&
245 locations[i].getSubReg() == LocMO.getSubReg())
246 return i;
247 } else
248 for (unsigned i = 0, e = locations.size(); i != e; ++i)
249 if (LocMO.isIdenticalTo(locations[i]))
250 return i;
251 locations.push_back(LocMO);
252 // We are storing a MachineOperand outside a MachineInstr.
253 locations.back().clearParent();
254 // Don't store def operands.
255 if (locations.back().isReg()) {
256 if (locations.back().isDef())
257 locations.back().setIsDead(false);
258 locations.back().setIsUse();
259 }
260 return locations.size() - 1;
261 }
262
263 /// Ensure that all virtual register locations are mapped.
264 void mapVirtRegs(LDVImpl *LDV);
265
266 /// Add a definition point to this value.
267 void addDef(SlotIndex Idx, const MachineOperand &LocMO, bool IsIndirect) {
268 DbgValueLocation Loc(getLocationNo(LocMO), IsIndirect);
269 // Add a singular (Idx,Idx) -> Loc mapping.
270 LocMap::iterator I = locInts.find(Idx);
271 if (!I.valid() || I.start() != Idx)
272 I.insert(Idx, Idx.getNextSlot(), Loc);
273 else
274 // A later DBG_VALUE at the same SlotIndex overrides the old location.
275 I.setValue(Loc);
276 }
277
278 /// Extend the current definition as far as possible down.
279 ///
280 /// Stop when meeting an existing def or when leaving the live
281 /// range of VNI. End points where VNI is no longer live are added to Kills.
282 ///
283 /// We only propagate DBG_VALUES locally here. LiveDebugValues performs a
284 /// data-flow analysis to propagate them beyond basic block boundaries.
285 ///
286 /// \param Idx Starting point for the definition.
287 /// \param Loc Location number to propagate.
288 /// \param LR Restrict liveness to where LR has the value VNI. May be null.
289 /// \param VNI When LR is not null, this is the value to restrict to.
290 /// \param [out] Kills Append end points of VNI's live range to Kills.
291 /// \param LIS Live intervals analysis.
292 void extendDef(SlotIndex Idx, DbgValueLocation Loc,
293 LiveRange *LR, const VNInfo *VNI,
294 SmallVectorImpl<SlotIndex> *Kills,
295 LiveIntervals &LIS);
296
297 /// The value in LI/LocNo may be copies to other registers. Determine if
298 /// any of the copies are available at the kill points, and add defs if
299 /// possible.
300 ///
301 /// \param LI Scan for copies of the value in LI->reg.
302 /// \param LocNo Location number of LI->reg.
303 /// \param WasIndirect Indicates if the original use of LI->reg was indirect
304 /// \param Kills Points where the range of LocNo could be extended.
305 /// \param [in,out] NewDefs Append (Idx, LocNo) of inserted defs here.
306 void addDefsFromCopies(
307 LiveInterval *LI, unsigned LocNo, bool WasIndirect,
308 const SmallVectorImpl<SlotIndex> &Kills,
309 SmallVectorImpl<std::pair<SlotIndex, DbgValueLocation>> &NewDefs,
310 MachineRegisterInfo &MRI, LiveIntervals &LIS);
311
312 /// Compute the live intervals of all locations after collecting all their
313 /// def points.
314 void computeIntervals(MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
315 LiveIntervals &LIS, LexicalScopes &LS);
316
317 /// Replace OldReg ranges with NewRegs ranges where NewRegs is
318 /// live. Returns true if any changes were made.
319 bool splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
320 LiveIntervals &LIS);
321
322 /// Rewrite virtual register locations according to the provided virtual
323 /// register map. Record the stack slot offsets for the locations that
324 /// were spilled.
325 void rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF,
326 const TargetInstrInfo &TII,
327 const TargetRegisterInfo &TRI,
328 SpillOffsetMap &SpillOffsets);
329
330 /// Recreate DBG_VALUE instruction from data structures.
331 void emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
332 const TargetInstrInfo &TII,
333 const TargetRegisterInfo &TRI,
334 const SpillOffsetMap &SpillOffsets);
335
336 /// Return DebugLoc of this UserValue.
337 DebugLoc getDebugLoc() { return dl;}
338
339 void print(raw_ostream &, const TargetRegisterInfo *);
340};
341
342/// Implementation of the LiveDebugVariables pass.
343class LDVImpl {
344 LiveDebugVariables &pass;
345 LocMap::Allocator allocator;
346 MachineFunction *MF = nullptr;
347 LiveIntervals *LIS;
348 const TargetRegisterInfo *TRI;
349
350 /// Whether emitDebugValues is called.
351 bool EmitDone = false;
352
353 /// Whether the machine function is modified during the pass.
354 bool ModifiedMF = false;
355
356 /// All allocated UserValue instances.
357 SmallVector<std::unique_ptr<UserValue>, 8> userValues;
358
359 /// Map virtual register to eq class leader.
360 using VRMap = DenseMap<unsigned, UserValue *>;
361 VRMap virtRegToEqClass;
362
363 /// Map user variable to eq class leader.
364 using UVMap = DenseMap<const DILocalVariable *, UserValue *>;
365 UVMap userVarMap;
366
367 /// Find or create a UserValue.
368 UserValue *getUserValue(const DILocalVariable *Var, const DIExpression *Expr,
369 const DebugLoc &DL);
370
371 /// Find the EC leader for VirtReg or null.
372 UserValue *lookupVirtReg(unsigned VirtReg);
373
374 /// Add DBG_VALUE instruction to our maps.
375 ///
376 /// \param MI DBG_VALUE instruction
377 /// \param Idx Last valid SLotIndex before instruction.
378 ///
379 /// \returns True if the DBG_VALUE instruction should be deleted.
380 bool handleDebugValue(MachineInstr &MI, SlotIndex Idx);
381
382 /// Collect and erase all DBG_VALUE instructions, adding a UserValue def
383 /// for each instruction.
384 ///
385 /// \param mf MachineFunction to be scanned.
386 ///
387 /// \returns True if any debug values were found.
388 bool collectDebugValues(MachineFunction &mf);
389
390 /// Compute the live intervals of all user values after collecting all
391 /// their def points.
392 void computeIntervals();
393
394public:
395 LDVImpl(LiveDebugVariables *ps) : pass(*ps) {}
396
397 bool runOnMachineFunction(MachineFunction &mf);
398
399 /// Release all memory.
400 void clear() {
401 MF = nullptr;
402 userValues.clear();
403 virtRegToEqClass.clear();
404 userVarMap.clear();
405 // Make sure we call emitDebugValues if the machine function was modified.
406 assert((!ModifiedMF || EmitDone) &&(((!ModifiedMF || EmitDone) && "Dbg values are not emitted in LDV"
) ? static_cast<void> (0) : __assert_fail ("(!ModifiedMF || EmitDone) && \"Dbg values are not emitted in LDV\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 407, __PRETTY_FUNCTION__))
407 "Dbg values are not emitted in LDV")(((!ModifiedMF || EmitDone) && "Dbg values are not emitted in LDV"
) ? static_cast<void> (0) : __assert_fail ("(!ModifiedMF || EmitDone) && \"Dbg values are not emitted in LDV\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 407, __PRETTY_FUNCTION__))
;
408 EmitDone = false;
409 ModifiedMF = false;
410 }
411
412 /// Map virtual register to an equivalence class.
413 void mapVirtReg(unsigned VirtReg, UserValue *EC);
414
415 /// Replace all references to OldReg with NewRegs.
416 void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs);
417
418 /// Recreate DBG_VALUE instruction from data structures.
419 void emitDebugValues(VirtRegMap *VRM);
420
421 void print(raw_ostream&);
422};
423
424} // end anonymous namespace
425
426#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
427static void printDebugLoc(const DebugLoc &DL, raw_ostream &CommentOS,
428 const LLVMContext &Ctx) {
429 if (!DL)
430 return;
431
432 auto *Scope = cast<DIScope>(DL.getScope());
433 // Omit the directory, because it's likely to be long and uninteresting.
434 CommentOS << Scope->getFilename();
435 CommentOS << ':' << DL.getLine();
436 if (DL.getCol() != 0)
437 CommentOS << ':' << DL.getCol();
438
439 DebugLoc InlinedAtDL = DL.getInlinedAt();
440 if (!InlinedAtDL)
441 return;
442
443 CommentOS << " @[ ";
444 printDebugLoc(InlinedAtDL, CommentOS, Ctx);
445 CommentOS << " ]";
446}
447
448static void printExtendedName(raw_ostream &OS, const DILocalVariable *V,
449 const DILocation *DL) {
450 const LLVMContext &Ctx = V->getContext();
451 StringRef Res = V->getName();
452 if (!Res.empty())
453 OS << Res << "," << V->getLine();
454 if (auto *InlinedAt = DL->getInlinedAt()) {
455 if (DebugLoc InlinedAtDL = InlinedAt) {
456 OS << " @[";
457 printDebugLoc(InlinedAtDL, OS, Ctx);
458 OS << "]";
459 }
460 }
461}
462
463void UserValue::print(raw_ostream &OS, const TargetRegisterInfo *TRI) {
464 auto *DV = cast<DILocalVariable>(Variable);
465 OS << "!\"";
466 printExtendedName(OS, DV, dl);
467
468 OS << "\"\t";
469 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
470 OS << " [" << I.start() << ';' << I.stop() << "):";
471 if (I.value().isUndef())
472 OS << "undef";
473 else {
474 OS << I.value().locNo();
475 if (I.value().wasIndirect())
476 OS << " ind";
477 }
478 }
479 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
480 OS << " Loc" << i << '=';
481 locations[i].print(OS, TRI);
482 }
483 OS << '\n';
484}
485
486void LDVImpl::print(raw_ostream &OS) {
487 OS << "********** DEBUG VARIABLES **********\n";
488 for (unsigned i = 0, e = userValues.size(); i != e; ++i)
489 userValues[i]->print(OS, TRI);
490}
491#endif
492
493void UserValue::mapVirtRegs(LDVImpl *LDV) {
494 for (unsigned i = 0, e = locations.size(); i != e; ++i)
495 if (locations[i].isReg() &&
496 TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
497 LDV->mapVirtReg(locations[i].getReg(), this);
498}
499
500UserValue *LDVImpl::getUserValue(const DILocalVariable *Var,
501 const DIExpression *Expr, const DebugLoc &DL) {
502 UserValue *&Leader = userVarMap[Var];
503 if (Leader) {
504 UserValue *UV = Leader->getLeader();
505 Leader = UV;
506 for (; UV; UV = UV->getNext())
507 if (UV->match(Var, Expr, DL->getInlinedAt()))
508 return UV;
509 }
510
511 userValues.push_back(
512 llvm::make_unique<UserValue>(Var, Expr, DL, allocator));
513 UserValue *UV = userValues.back().get();
514 Leader = UserValue::merge(Leader, UV);
515 return UV;
516}
517
518void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
519 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs")((TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs"
) ? static_cast<void> (0) : __assert_fail ("TargetRegisterInfo::isVirtualRegister(VirtReg) && \"Only map VirtRegs\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 519, __PRETTY_FUNCTION__))
;
520 UserValue *&Leader = virtRegToEqClass[VirtReg];
521 Leader = UserValue::merge(Leader, EC);
522}
523
524UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
525 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
526 return UV->getLeader();
527 return nullptr;
528}
529
530bool LDVImpl::handleDebugValue(MachineInstr &MI, SlotIndex Idx) {
531 // DBG_VALUE loc, offset, variable
532 if (MI.getNumOperands() != 4 ||
533 !(MI.getOperand(1).isReg() || MI.getOperand(1).isImm()) ||
534 !MI.getOperand(2).isMetadata()) {
535 LLVM_DEBUG(dbgs() << "Can't handle " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Can't handle " <<
MI; } } while (false)
;
536 return false;
537 }
538
539 // Detect invalid DBG_VALUE instructions, with a debug-use of a virtual
540 // register that hasn't been defined yet. If we do not remove those here, then
541 // the re-insertion of the DBG_VALUE instruction after register allocation
542 // will be incorrect.
543 // TODO: If earlier passes are corrected to generate sane debug information
544 // (and if the machine verifier is improved to catch this), then these checks
545 // could be removed or replaced by asserts.
546 bool Discard = false;
547 if (MI.getOperand(0).isReg() &&
548 TargetRegisterInfo::isVirtualRegister(MI.getOperand(0).getReg())) {
549 const unsigned Reg = MI.getOperand(0).getReg();
550 if (!LIS->hasInterval(Reg)) {
551 // The DBG_VALUE is described by a virtual register that does not have a
552 // live interval. Discard the DBG_VALUE.
553 Discard = true;
554 LLVM_DEBUG(dbgs() << "Discarding debug info (no LIS interval): " << Idxdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (no LIS interval): "
<< Idx << " " << MI; } } while (false)
555 << " " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (no LIS interval): "
<< Idx << " " << MI; } } while (false)
;
556 } else {
557 // The DBG_VALUE is only valid if either Reg is live out from Idx, or Reg
558 // is defined dead at Idx (where Idx is the slot index for the instruction
559 // preceeding the DBG_VALUE).
560 const LiveInterval &LI = LIS->getInterval(Reg);
561 LiveQueryResult LRQ = LI.Query(Idx);
562 if (!LRQ.valueOutOrDead()) {
563 // We have found a DBG_VALUE with the value in a virtual register that
564 // is not live. Discard the DBG_VALUE.
565 Discard = true;
566 LLVM_DEBUG(dbgs() << "Discarding debug info (reg not live): " << Idxdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (reg not live): "
<< Idx << " " << MI; } } while (false)
567 << " " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (reg not live): "
<< Idx << " " << MI; } } while (false)
;
568 }
569 }
570 }
571
572 // Get or create the UserValue for (variable,offset) here.
573 bool IsIndirect = MI.getOperand(1).isImm();
574 if (IsIndirect)
575 assert(MI.getOperand(1).getImm() == 0 && "DBG_VALUE with nonzero offset")((MI.getOperand(1).getImm() == 0 && "DBG_VALUE with nonzero offset"
) ? static_cast<void> (0) : __assert_fail ("MI.getOperand(1).getImm() == 0 && \"DBG_VALUE with nonzero offset\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 575, __PRETTY_FUNCTION__))
;
576 const DILocalVariable *Var = MI.getDebugVariable();
577 const DIExpression *Expr = MI.getDebugExpression();
578 UserValue *UV =
579 getUserValue(Var, Expr, MI.getDebugLoc());
580 if (!Discard)
581 UV->addDef(Idx, MI.getOperand(0), IsIndirect);
582 else {
583 MachineOperand MO = MachineOperand::CreateReg(0U, false);
584 MO.setIsDebug();
585 UV->addDef(Idx, MO, false);
586 }
587 return true;
588}
589
590bool LDVImpl::collectDebugValues(MachineFunction &mf) {
591 bool Changed = false;
592 for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
593 ++MFI) {
594 MachineBasicBlock *MBB = &*MFI;
595 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
596 MBBI != MBBE;) {
597 // Use the first debug instruction in the sequence to get a SlotIndex
598 // for following consecutive debug instructions.
599 if (!MBBI->isDebugInstr()) {
600 ++MBBI;
601 continue;
602 }
603 // Debug instructions has no slot index. Use the previous
604 // non-debug instruction's SlotIndex as its SlotIndex.
605 SlotIndex Idx =
606 MBBI == MBB->begin()
607 ? LIS->getMBBStartIdx(MBB)
608 : LIS->getInstructionIndex(*std::prev(MBBI)).getRegSlot();
609 // Handle consecutive debug instructions with the same slot index.
610 do {
611 // Only handle DBG_VALUE in handleDebugValue(). Skip all other
612 // kinds of debug instructions.
613 if (MBBI->isDebugValue() && handleDebugValue(*MBBI, Idx)) {
614 MBBI = MBB->erase(MBBI);
615 Changed = true;
616 } else
617 ++MBBI;
618 } while (MBBI != MBBE && MBBI->isDebugInstr());
619 }
620 }
621 return Changed;
622}
623
624void UserValue::extendDef(SlotIndex Idx, DbgValueLocation Loc, LiveRange *LR,
625 const VNInfo *VNI, SmallVectorImpl<SlotIndex> *Kills,
626 LiveIntervals &LIS) {
627 SlotIndex Start = Idx;
628 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
629 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
630 LocMap::iterator I = locInts.find(Start);
631
632 // Limit to VNI's live range.
633 bool ToEnd = true;
634 if (LR && VNI) {
635 LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
636 if (!Segment || Segment->valno != VNI) {
637 if (Kills)
638 Kills->push_back(Start);
639 return;
640 }
641 if (Segment->end < Stop) {
642 Stop = Segment->end;
643 ToEnd = false;
644 }
645 }
646
647 // There could already be a short def at Start.
648 if (I.valid() && I.start() <= Start) {
649 // Stop when meeting a different location or an already extended interval.
650 Start = Start.getNextSlot();
651 if (I.value() != Loc || I.stop() != Start)
652 return;
653 // This is a one-slot placeholder. Just skip it.
654 ++I;
655 }
656
657 // Limited by the next def.
658 if (I.valid() && I.start() < Stop) {
659 Stop = I.start();
660 ToEnd = false;
Value stored to 'ToEnd' is never read
661 }
662 // Limited by VNI's live range.
663 else if (!ToEnd && Kills)
664 Kills->push_back(Stop);
665
666 if (Start < Stop)
667 I.insert(Start, Stop, Loc);
668}
669
670void UserValue::addDefsFromCopies(
671 LiveInterval *LI, unsigned LocNo, bool WasIndirect,
672 const SmallVectorImpl<SlotIndex> &Kills,
673 SmallVectorImpl<std::pair<SlotIndex, DbgValueLocation>> &NewDefs,
674 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
675 if (Kills.empty())
676 return;
677 // Don't track copies from physregs, there are too many uses.
678 if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
679 return;
680
681 // Collect all the (vreg, valno) pairs that are copies of LI.
682 SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
683 for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg)) {
684 MachineInstr *MI = MO.getParent();
685 // Copies of the full value.
686 if (MO.getSubReg() || !MI->isCopy())
687 continue;
688 unsigned DstReg = MI->getOperand(0).getReg();
689
690 // Don't follow copies to physregs. These are usually setting up call
691 // arguments, and the argument registers are always call clobbered. We are
692 // better off in the source register which could be a callee-saved register,
693 // or it could be spilled.
694 if (!TargetRegisterInfo::isVirtualRegister(DstReg))
695 continue;
696
697 // Is LocNo extended to reach this copy? If not, another def may be blocking
698 // it, or we are looking at a wrong value of LI.
699 SlotIndex Idx = LIS.getInstructionIndex(*MI);
700 LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
701 if (!I.valid() || I.value().locNo() != LocNo)
702 continue;
703
704 if (!LIS.hasInterval(DstReg))
705 continue;
706 LiveInterval *DstLI = &LIS.getInterval(DstReg);
707 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
708 assert(DstVNI && DstVNI->def == Idx.getRegSlot() && "Bad copy value")((DstVNI && DstVNI->def == Idx.getRegSlot() &&
"Bad copy value") ? static_cast<void> (0) : __assert_fail
("DstVNI && DstVNI->def == Idx.getRegSlot() && \"Bad copy value\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 708, __PRETTY_FUNCTION__))
;
709 CopyValues.push_back(std::make_pair(DstLI, DstVNI));
710 }
711
712 if (CopyValues.empty())
713 return;
714
715 LLVM_DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LIdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Got " << CopyValues
.size() << " copies of " << *LI << '\n'; } }
while (false)
716 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Got " << CopyValues
.size() << " copies of " << *LI << '\n'; } }
while (false)
;
717
718 // Try to add defs of the copied values for each kill point.
719 for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
720 SlotIndex Idx = Kills[i];
721 for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
722 LiveInterval *DstLI = CopyValues[j].first;
723 const VNInfo *DstVNI = CopyValues[j].second;
724 if (DstLI->getVNInfoAt(Idx) != DstVNI)
725 continue;
726 // Check that there isn't already a def at Idx
727 LocMap::iterator I = locInts.find(Idx);
728 if (I.valid() && I.start() <= Idx)
729 continue;
730 LLVM_DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Kill at " << Idx <<
" covered by valno #" << DstVNI->id << " in "
<< *DstLI << '\n'; } } while (false)
731 << DstVNI->id << " in " << *DstLI << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Kill at " << Idx <<
" covered by valno #" << DstVNI->id << " in "
<< *DstLI << '\n'; } } while (false)
;
732 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
733 assert(CopyMI && CopyMI->isCopy() && "Bad copy value")((CopyMI && CopyMI->isCopy() && "Bad copy value"
) ? static_cast<void> (0) : __assert_fail ("CopyMI && CopyMI->isCopy() && \"Bad copy value\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 733, __PRETTY_FUNCTION__))
;
734 unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
735 DbgValueLocation NewLoc(LocNo, WasIndirect);
736 I.insert(Idx, Idx.getNextSlot(), NewLoc);
737 NewDefs.push_back(std::make_pair(Idx, NewLoc));
738 break;
739 }
740 }
741}
742
743void UserValue::computeIntervals(MachineRegisterInfo &MRI,
744 const TargetRegisterInfo &TRI,
745 LiveIntervals &LIS, LexicalScopes &LS) {
746 SmallVector<std::pair<SlotIndex, DbgValueLocation>, 16> Defs;
747
748 // Collect all defs to be extended (Skipping undefs).
749 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
750 if (!I.value().isUndef())
751 Defs.push_back(std::make_pair(I.start(), I.value()));
752
753 // Extend all defs, and possibly add new ones along the way.
754 for (unsigned i = 0; i != Defs.size(); ++i) {
755 SlotIndex Idx = Defs[i].first;
756 DbgValueLocation Loc = Defs[i].second;
757 const MachineOperand &LocMO = locations[Loc.locNo()];
758
759 if (!LocMO.isReg()) {
760 extendDef(Idx, Loc, nullptr, nullptr, nullptr, LIS);
761 continue;
762 }
763
764 // Register locations are constrained to where the register value is live.
765 if (TargetRegisterInfo::isVirtualRegister(LocMO.getReg())) {
766 LiveInterval *LI = nullptr;
767 const VNInfo *VNI = nullptr;
768 if (LIS.hasInterval(LocMO.getReg())) {
769 LI = &LIS.getInterval(LocMO.getReg());
770 VNI = LI->getVNInfoAt(Idx);
771 }
772 SmallVector<SlotIndex, 16> Kills;
773 extendDef(Idx, Loc, LI, VNI, &Kills, LIS);
774 // FIXME: Handle sub-registers in addDefsFromCopies. The problem is that
775 // if the original location for example is %vreg0:sub_hi, and we find a
776 // full register copy in addDefsFromCopies (at the moment it only handles
777 // full register copies), then we must add the sub1 sub-register index to
778 // the new location. However, that is only possible if the new virtual
779 // register is of the same regclass (or if there is an equivalent
780 // sub-register in that regclass). For now, simply skip handling copies if
781 // a sub-register is involved.
782 if (LI && !LocMO.getSubReg())
783 addDefsFromCopies(LI, Loc.locNo(), Loc.wasIndirect(), Kills, Defs, MRI,
784 LIS);
785 continue;
786 }
787
788 // For physregs, we only mark the start slot idx. DwarfDebug will see it
789 // as if the DBG_VALUE is valid up until the end of the basic block, or
790 // the next def of the physical register. So we do not need to extend the
791 // range. It might actually happen that the DBG_VALUE is the last use of
792 // the physical register (e.g. if this is an unused input argument to a
793 // function).
794 }
795
796 // The computed intervals may extend beyond the range of the debug
797 // location's lexical scope. In this case, splitting of an interval
798 // can result in an interval outside of the scope being created,
799 // causing extra unnecessary DBG_VALUEs to be emitted. To prevent
800 // this, trim the intervals to the lexical scope.
801
802 LexicalScope *Scope = LS.findLexicalScope(dl);
803 if (!Scope)
804 return;
805
806 SlotIndex PrevEnd;
807 LocMap::iterator I = locInts.begin();
808
809 // Iterate over the lexical scope ranges. Each time round the loop
810 // we check the intervals for overlap with the end of the previous
811 // range and the start of the next. The first range is handled as
812 // a special case where there is no PrevEnd.
813 for (const InsnRange &Range : Scope->getRanges()) {
814 SlotIndex RStart = LIS.getInstructionIndex(*Range.first);
815 SlotIndex REnd = LIS.getInstructionIndex(*Range.second);
816
817 // At the start of each iteration I has been advanced so that
818 // I.stop() >= PrevEnd. Check for overlap.
819 if (PrevEnd && I.start() < PrevEnd) {
820 SlotIndex IStop = I.stop();
821 DbgValueLocation Loc = I.value();
822
823 // Stop overlaps previous end - trim the end of the interval to
824 // the scope range.
825 I.setStopUnchecked(PrevEnd);
826 ++I;
827
828 // If the interval also overlaps the start of the "next" (i.e.
829 // current) range create a new interval for the remainder (which
830 // may be further trimmed).
831 if (RStart < IStop)
832 I.insert(RStart, IStop, Loc);
833 }
834
835 // Advance I so that I.stop() >= RStart, and check for overlap.
836 I.advanceTo(RStart);
837 if (!I.valid())
838 return;
839
840 if (I.start() < RStart) {
841 // Interval start overlaps range - trim to the scope range.
842 I.setStartUnchecked(RStart);
843 // Remember that this interval was trimmed.
844 trimmedDefs.insert(RStart);
845 }
846
847 // The end of a lexical scope range is the last instruction in the
848 // range. To convert to an interval we need the index of the
849 // instruction after it.
850 REnd = REnd.getNextIndex();
851
852 // Advance I to first interval outside current range.
853 I.advanceTo(REnd);
854 if (!I.valid())
855 return;
856
857 PrevEnd = REnd;
858 }
859
860 // Check for overlap with end of final range.
861 if (PrevEnd && I.start() < PrevEnd)
862 I.setStopUnchecked(PrevEnd);
863}
864
865void LDVImpl::computeIntervals() {
866 LexicalScopes LS;
867 LS.initialize(*MF);
868
869 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
870 userValues[i]->computeIntervals(MF->getRegInfo(), *TRI, *LIS, LS);
871 userValues[i]->mapVirtRegs(this);
872 }
873}
874
875bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
876 clear();
877 MF = &mf;
878 LIS = &pass.getAnalysis<LiveIntervals>();
879 TRI = mf.getSubtarget().getRegisterInfo();
880 LLVM_DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
<< mf.getName() << " **********\n"; } } while (false
)
881 << mf.getName() << " **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
<< mf.getName() << " **********\n"; } } while (false
)
;
882
883 bool Changed = collectDebugValues(mf);
884 computeIntervals();
885 LLVM_DEBUG(print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { print(dbgs()); } } while (false)
;
886 ModifiedMF = Changed;
887 return Changed;
888}
889
890static void removeDebugValues(MachineFunction &mf) {
891 for (MachineBasicBlock &MBB : mf) {
892 for (auto MBBI = MBB.begin(), MBBE = MBB.end(); MBBI != MBBE; ) {
893 if (!MBBI->isDebugValue()) {
894 ++MBBI;
895 continue;
896 }
897 MBBI = MBB.erase(MBBI);
898 }
899 }
900}
901
902bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
903 if (!EnableLDV)
904 return false;
905 if (!mf.getFunction().getSubprogram()) {
906 removeDebugValues(mf);
907 return false;
908 }
909 if (!pImpl)
910 pImpl = new LDVImpl(this);
911 return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
912}
913
914void LiveDebugVariables::releaseMemory() {
915 if (pImpl)
916 static_cast<LDVImpl*>(pImpl)->clear();
917}
918
919LiveDebugVariables::~LiveDebugVariables() {
920 if (pImpl)
921 delete static_cast<LDVImpl*>(pImpl);
922}
923
924//===----------------------------------------------------------------------===//
925// Live Range Splitting
926//===----------------------------------------------------------------------===//
927
928bool
929UserValue::splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
930 LiveIntervals& LIS) {
931 LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
932 dbgs() << "Splitting Loc" << OldLocNo << '\t';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
933 print(dbgs(), nullptr);do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
934 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
;
935 bool DidChange = false;
936 LocMap::iterator LocMapI;
937 LocMapI.setMap(locInts);
938 for (unsigned i = 0; i != NewRegs.size(); ++i) {
939 LiveInterval *LI = &LIS.getInterval(NewRegs[i]);
940 if (LI->empty())
941 continue;
942
943 // Don't allocate the new LocNo until it is needed.
944 unsigned NewLocNo = UndefLocNo;
945
946 // Iterate over the overlaps between locInts and LI.
947 LocMapI.find(LI->beginIndex());
948 if (!LocMapI.valid())
949 continue;
950 LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
951 LiveInterval::iterator LIE = LI->end();
952 while (LocMapI.valid() && LII != LIE) {
953 // At this point, we know that LocMapI.stop() > LII->start.
954 LII = LI->advanceTo(LII, LocMapI.start());
955 if (LII == LIE)
956 break;
957
958 // Now LII->end > LocMapI.start(). Do we have an overlap?
959 if (LocMapI.value().locNo() == OldLocNo && LII->start < LocMapI.stop()) {
960 // Overlapping correct location. Allocate NewLocNo now.
961 if (NewLocNo == UndefLocNo) {
962 MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
963 MO.setSubReg(locations[OldLocNo].getSubReg());
964 NewLocNo = getLocationNo(MO);
965 DidChange = true;
966 }
967
968 SlotIndex LStart = LocMapI.start();
969 SlotIndex LStop = LocMapI.stop();
970 DbgValueLocation OldLoc = LocMapI.value();
971
972 // Trim LocMapI down to the LII overlap.
973 if (LStart < LII->start)
974 LocMapI.setStartUnchecked(LII->start);
975 if (LStop > LII->end)
976 LocMapI.setStopUnchecked(LII->end);
977
978 // Change the value in the overlap. This may trigger coalescing.
979 LocMapI.setValue(OldLoc.changeLocNo(NewLocNo));
980
981 // Re-insert any removed OldLocNo ranges.
982 if (LStart < LocMapI.start()) {
983 LocMapI.insert(LStart, LocMapI.start(), OldLoc);
984 ++LocMapI;
985 assert(LocMapI.valid() && "Unexpected coalescing")((LocMapI.valid() && "Unexpected coalescing") ? static_cast
<void> (0) : __assert_fail ("LocMapI.valid() && \"Unexpected coalescing\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 985, __PRETTY_FUNCTION__))
;
986 }
987 if (LStop > LocMapI.stop()) {
988 ++LocMapI;
989 LocMapI.insert(LII->end, LStop, OldLoc);
990 --LocMapI;
991 }
992 }
993
994 // Advance to the next overlap.
995 if (LII->end < LocMapI.stop()) {
996 if (++LII == LIE)
997 break;
998 LocMapI.advanceTo(LII->start);
999 } else {
1000 ++LocMapI;
1001 if (!LocMapI.valid())
1002 break;
1003 LII = LI->advanceTo(LII, LocMapI.start());
1004 }
1005 }
1006 }
1007
1008 // Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
1009 locations.erase(locations.begin() + OldLocNo);
1010 LocMapI.goToBegin();
1011 while (LocMapI.valid()) {
1012 DbgValueLocation v = LocMapI.value();
1013 if (v.locNo() == OldLocNo) {
1014 LLVM_DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Erasing [" << LocMapI
.start() << ';' << LocMapI.stop() << ")\n";
} } while (false)
1015 << LocMapI.stop() << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Erasing [" << LocMapI
.start() << ';' << LocMapI.stop() << ")\n";
} } while (false)
;
1016 LocMapI.erase();
1017 } else {
1018 // Undef values always have location number UndefLocNo, so don't change
1019 // locNo in that case. See getLocationNo().
1020 if (!v.isUndef() && v.locNo() > OldLocNo)
1021 LocMapI.setValueUnchecked(v.changeLocNo(v.locNo() - 1));
1022 ++LocMapI;
1023 }
1024 }
1025
1026 LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1027 dbgs() << "Split result: \t";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1028 print(dbgs(), nullptr);do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1029 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
;
1030 return DidChange;
1031}
1032
1033bool
1034UserValue::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
1035 LiveIntervals &LIS) {
1036 bool DidChange = false;
1037 // Split locations referring to OldReg. Iterate backwards so splitLocation can
1038 // safely erase unused locations.
1039 for (unsigned i = locations.size(); i ; --i) {
1040 unsigned LocNo = i-1;
1041 const MachineOperand *Loc = &locations[LocNo];
1042 if (!Loc->isReg() || Loc->getReg() != OldReg)
1043 continue;
1044 DidChange |= splitLocation(LocNo, NewRegs, LIS);
1045 }
1046 return DidChange;
1047}
1048
1049void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs) {
1050 bool DidChange = false;
1051 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
1052 DidChange |= UV->splitRegister(OldReg, NewRegs, *LIS);
1053
1054 if (!DidChange)
1055 return;
1056
1057 // Map all of the new virtual registers.
1058 UserValue *UV = lookupVirtReg(OldReg);
1059 for (unsigned i = 0; i != NewRegs.size(); ++i)
1060 mapVirtReg(NewRegs[i], UV);
1061}
1062
1063void LiveDebugVariables::
1064splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, LiveIntervals &LIS) {
1065 if (pImpl)
1066 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
1067}
1068
1069void UserValue::rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF,
1070 const TargetInstrInfo &TII,
1071 const TargetRegisterInfo &TRI,
1072 SpillOffsetMap &SpillOffsets) {
1073 // Build a set of new locations with new numbers so we can coalesce our
1074 // IntervalMap if two vreg intervals collapse to the same physical location.
1075 // Use MapVector instead of SetVector because MapVector::insert returns the
1076 // position of the previously or newly inserted element. The boolean value
1077 // tracks if the location was produced by a spill.
1078 // FIXME: This will be problematic if we ever support direct and indirect
1079 // frame index locations, i.e. expressing both variables in memory and
1080 // 'int x, *px = &x'. The "spilled" bit must become part of the location.
1081 MapVector<MachineOperand, std::pair<bool, unsigned>> NewLocations;
1082 SmallVector<unsigned, 4> LocNoMap(locations.size());
1083 for (unsigned I = 0, E = locations.size(); I != E; ++I) {
1084 bool Spilled = false;
1085 unsigned SpillOffset = 0;
1086 MachineOperand Loc = locations[I];
1087 // Only virtual registers are rewritten.
1088 if (Loc.isReg() && Loc.getReg() &&
1089 TargetRegisterInfo::isVirtualRegister(Loc.getReg())) {
1090 unsigned VirtReg = Loc.getReg();
1091 if (VRM.isAssignedReg(VirtReg) &&
1092 TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
1093 // This can create a %noreg operand in rare cases when the sub-register
1094 // index is no longer available. That means the user value is in a
1095 // non-existent sub-register, and %noreg is exactly what we want.
1096 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
1097 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
1098 // Retrieve the stack slot offset.
1099 unsigned SpillSize;
1100 const MachineRegisterInfo &MRI = MF.getRegInfo();
1101 const TargetRegisterClass *TRC = MRI.getRegClass(VirtReg);
1102 bool Success = TII.getStackSlotRange(TRC, Loc.getSubReg(), SpillSize,
1103 SpillOffset, MF);
1104
1105 // FIXME: Invalidate the location if the offset couldn't be calculated.
1106 (void)Success;
1107
1108 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
1109 Spilled = true;
1110 } else {
1111 Loc.setReg(0);
1112 Loc.setSubReg(0);
1113 }
1114 }
1115
1116 // Insert this location if it doesn't already exist and record a mapping
1117 // from the old number to the new number.
1118 auto InsertResult = NewLocations.insert({Loc, {Spilled, SpillOffset}});
1119 unsigned NewLocNo = std::distance(NewLocations.begin(), InsertResult.first);
1120 LocNoMap[I] = NewLocNo;
1121 }
1122
1123 // Rewrite the locations and record the stack slot offsets for spills.
1124 locations.clear();
1125 SpillOffsets.clear();
1126 for (auto &Pair : NewLocations) {
1127 bool Spilled;
1128 unsigned SpillOffset;
1129 std::tie(Spilled, SpillOffset) = Pair.second;
1130 locations.push_back(Pair.first);
1131 if (Spilled) {
1132 unsigned NewLocNo = std::distance(&*NewLocations.begin(), &Pair);
1133 SpillOffsets[NewLocNo] = SpillOffset;
1134 }
1135 }
1136
1137 // Update the interval map, but only coalesce left, since intervals to the
1138 // right use the old location numbers. This should merge two contiguous
1139 // DBG_VALUE intervals with different vregs that were allocated to the same
1140 // physical register.
1141 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
1142 DbgValueLocation Loc = I.value();
1143 // Undef values don't exist in locations (and thus not in LocNoMap either)
1144 // so skip over them. See getLocationNo().
1145 if (Loc.isUndef())
1146 continue;
1147 unsigned NewLocNo = LocNoMap[Loc.locNo()];
1148 I.setValueUnchecked(Loc.changeLocNo(NewLocNo));
1149 I.setStart(I.start());
1150 }
1151}
1152
1153/// Find an iterator for inserting a DBG_VALUE instruction.
1154static MachineBasicBlock::iterator
1155findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
1156 LiveIntervals &LIS) {
1157 SlotIndex Start = LIS.getMBBStartIdx(MBB);
1158 Idx = Idx.getBaseIndex();
1159
1160 // Try to find an insert location by going backwards from Idx.
1161 MachineInstr *MI;
1162 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
1163 // We've reached the beginning of MBB.
1164 if (Idx == Start) {
1165 MachineBasicBlock::iterator I = MBB->SkipPHIsLabelsAndDebug(MBB->begin());
1166 return I;
1167 }
1168 Idx = Idx.getPrevIndex();
1169 }
1170
1171 // Don't insert anything after the first terminator, though.
1172 return MI->isTerminator() ? MBB->getFirstTerminator() :
1173 std::next(MachineBasicBlock::iterator(MI));
1174}
1175
1176/// Find an iterator for inserting the next DBG_VALUE instruction
1177/// (or end if no more insert locations found).
1178static MachineBasicBlock::iterator
1179findNextInsertLocation(MachineBasicBlock *MBB,
1180 MachineBasicBlock::iterator I,
1181 SlotIndex StopIdx, MachineOperand &LocMO,
1182 LiveIntervals &LIS,
1183 const TargetRegisterInfo &TRI) {
1184 if (!LocMO.isReg())
1185 return MBB->instr_end();
1186 unsigned Reg = LocMO.getReg();
1187
1188 // Find the next instruction in the MBB that define the register Reg.
1189 while (I != MBB->end() && !I->isTerminator()) {
1190 if (!LIS.isNotInMIMap(*I) &&
1191 SlotIndex::isEarlierEqualInstr(StopIdx, LIS.getInstructionIndex(*I)))
1192 break;
1193 if (I->definesRegister(Reg, &TRI))
1194 // The insert location is directly after the instruction/bundle.
1195 return std::next(I);
1196 ++I;
1197 }
1198 return MBB->end();
1199}
1200
1201void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
1202 SlotIndex StopIdx, DbgValueLocation Loc,
1203 bool Spilled, unsigned SpillOffset,
1204 LiveIntervals &LIS, const TargetInstrInfo &TII,
1205 const TargetRegisterInfo &TRI) {
1206 SlotIndex MBBEndIdx = LIS.getMBBEndIdx(&*MBB);
1207 // Only search within the current MBB.
1208 StopIdx = (MBBEndIdx < StopIdx) ? MBBEndIdx : StopIdx;
1209 MachineBasicBlock::iterator I = findInsertLocation(MBB, StartIdx, LIS);
1210 // Undef values don't exist in locations so create new "noreg" register MOs
1211 // for them. See getLocationNo().
1212 MachineOperand MO = !Loc.isUndef() ?
1213 locations[Loc.locNo()] :
1214 MachineOperand::CreateReg(/* Reg */ 0, /* isDef */ false, /* isImp */ false,
1215 /* isKill */ false, /* isDead */ false,
1216 /* isUndef */ false, /* isEarlyClobber */ false,
1217 /* SubReg */ 0, /* isDebug */ true);
1218
1219 ++NumInsertedDebugValues;
1220
1221 assert(cast<DILocalVariable>(Variable)((cast<DILocalVariable>(Variable) ->isValidLocationForIntrinsic
(getDebugLoc()) && "Expected inlined-at fields to agree"
) ? static_cast<void> (0) : __assert_fail ("cast<DILocalVariable>(Variable) ->isValidLocationForIntrinsic(getDebugLoc()) && \"Expected inlined-at fields to agree\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 1223, __PRETTY_FUNCTION__))
1222 ->isValidLocationForIntrinsic(getDebugLoc()) &&((cast<DILocalVariable>(Variable) ->isValidLocationForIntrinsic
(getDebugLoc()) && "Expected inlined-at fields to agree"
) ? static_cast<void> (0) : __assert_fail ("cast<DILocalVariable>(Variable) ->isValidLocationForIntrinsic(getDebugLoc()) && \"Expected inlined-at fields to agree\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 1223, __PRETTY_FUNCTION__))
1223 "Expected inlined-at fields to agree")((cast<DILocalVariable>(Variable) ->isValidLocationForIntrinsic
(getDebugLoc()) && "Expected inlined-at fields to agree"
) ? static_cast<void> (0) : __assert_fail ("cast<DILocalVariable>(Variable) ->isValidLocationForIntrinsic(getDebugLoc()) && \"Expected inlined-at fields to agree\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 1223, __PRETTY_FUNCTION__))
;
1224
1225 // If the location was spilled, the new DBG_VALUE will be indirect. If the
1226 // original DBG_VALUE was indirect, we need to add DW_OP_deref to indicate
1227 // that the original virtual register was a pointer. Also, add the stack slot
1228 // offset for the spilled register to the expression.
1229 const DIExpression *Expr = Expression;
1230 bool IsIndirect = Loc.wasIndirect();
1231 if (Spilled) {
1232 auto Deref = IsIndirect ? DIExpression::WithDeref : DIExpression::NoDeref;
1233 Expr =
1234 DIExpression::prepend(Expr, DIExpression::NoDeref, SpillOffset, Deref);
1235 IsIndirect = true;
1236 }
1237
1238 assert((!Spilled || MO.isFI()) && "a spilled location must be a frame index")(((!Spilled || MO.isFI()) && "a spilled location must be a frame index"
) ? static_cast<void> (0) : __assert_fail ("(!Spilled || MO.isFI()) && \"a spilled location must be a frame index\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/CodeGen/LiveDebugVariables.cpp"
, 1238, __PRETTY_FUNCTION__))
;
1239
1240 do {
1241 BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
1242 IsIndirect, MO, Variable, Expr);
1243
1244 // Continue and insert DBG_VALUES after every redefinition of register
1245 // associated with the debug value within the range
1246 I = findNextInsertLocation(MBB, I, StopIdx, MO, LIS, TRI);
1247 } while (I != MBB->end());
1248}
1249
1250void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
1251 const TargetInstrInfo &TII,
1252 const TargetRegisterInfo &TRI,
1253 const SpillOffsetMap &SpillOffsets) {
1254 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
1255
1256 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
1257 SlotIndex Start = I.start();
1258 SlotIndex Stop = I.stop();
1259 DbgValueLocation Loc = I.value();
1260 auto SpillIt =
1261 !Loc.isUndef() ? SpillOffsets.find(Loc.locNo()) : SpillOffsets.end();
1262 bool Spilled = SpillIt != SpillOffsets.end();
1263 unsigned SpillOffset = Spilled ? SpillIt->second : 0;
1264
1265 // If the interval start was trimmed to the lexical scope insert the
1266 // DBG_VALUE at the previous index (otherwise it appears after the
1267 // first instruction in the range).
1268 if (trimmedDefs.count(Start))
1269 Start = Start.getPrevIndex();
1270
1271 LLVM_DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << Loc.locNo())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "\t[" << Start <<
';' << Stop << "):" << Loc.locNo(); } } while
(false)
;
1272 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start)->getIterator();
1273 SlotIndex MBBEnd = LIS.getMBBEndIdx(&*MBB);
1274
1275 LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB) << '-' << MBBEnd; } } while (false)
;
1276 insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, SpillOffset, LIS, TII,
1277 TRI);
1278 // This interval may span multiple basic blocks.
1279 // Insert a DBG_VALUE into each one.
1280 while (Stop > MBBEnd) {
1281 // Move to the next block.
1282 Start = MBBEnd;
1283 if (++MBB == MFEnd)
1284 break;
1285 MBBEnd = LIS.getMBBEndIdx(&*MBB);
1286 LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB) << '-' << MBBEnd; } } while (false)
;
1287 insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, SpillOffset, LIS, TII,
1288 TRI);
1289 }
1290 LLVM_DEBUG(dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << '\n'; } } while (false)
;
1291 if (MBB == MFEnd)
1292 break;
1293
1294 ++I;
1295 }
1296}
1297
1298void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
1299 LLVM_DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n"
; } } while (false)
;
1300 if (!MF)
1301 return;
1302 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
1303 SpillOffsetMap SpillOffsets;
1304 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
1305 LLVM_DEBUG(userValues[i]->print(dbgs(), TRI))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { userValues[i]->print(dbgs(), TRI); } }
while (false)
;
1306 userValues[i]->rewriteLocations(*VRM, *MF, *TII, *TRI, SpillOffsets);
1307 userValues[i]->emitDebugValues(VRM, *LIS, *TII, *TRI, SpillOffsets);
1308 }
1309 EmitDone = true;
1310}
1311
1312void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
1313 if (pImpl)
1314 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
1315}
1316
1317bool LiveDebugVariables::doInitialization(Module &M) {
1318 return Pass::doInitialization(M);
1319}
1320
1321#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1322LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void LiveDebugVariables::dump() const {
1323 if (pImpl)
1324 static_cast<LDVImpl*>(pImpl)->print(dbgs());
1325}
1326#endif