Bug Summary

File:lib/CodeGen/LiveDebugVariables.cpp
Warning:line 635, 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-eagerly-assume -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 -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-7/lib/clang/7.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-7~svn329677/build-llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen -I /build/llvm-toolchain-snapshot-7~svn329677/build-llvm/include -I /build/llvm-toolchain-snapshot-7~svn329677/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0/backward -internal-isystem /usr/include/clang/7.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-7/lib/clang/7.0.0/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-7~svn329677/build-llvm/lib/CodeGen -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-04-11-031539-24776-1 -x c++ /build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp
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/IR/DebugInfoMetadata.h"
48#include "llvm/IR/DebugLoc.h"
49#include "llvm/IR/Function.h"
50#include "llvm/IR/Metadata.h"
51#include "llvm/MC/MCRegisterInfo.h"
52#include "llvm/Pass.h"
53#include "llvm/Support/Casting.h"
54#include "llvm/Support/CommandLine.h"
55#include "llvm/Support/Compiler.h"
56#include "llvm/Support/Debug.h"
57#include "llvm/Support/raw_ostream.h"
58#include <algorithm>
59#include <cassert>
60#include <iterator>
61#include <memory>
62#include <utility>
63
64using namespace llvm;
65
66#define DEBUG_TYPE"livedebugvars" "livedebugvars"
67
68static cl::opt<bool>
69EnableLDV("live-debug-variables", cl::init(true),
70 cl::desc("Enable the live debug variables pass"), cl::Hidden);
71
72STATISTIC(NumInsertedDebugValues, "Number of DBG_VALUEs inserted")static llvm::Statistic NumInsertedDebugValues = {"livedebugvars"
, "NumInsertedDebugValues", "Number of DBG_VALUEs inserted", {
0}, {false}}
;
73
74char LiveDebugVariables::ID = 0;
75
76INITIALIZE_PASS_BEGIN(LiveDebugVariables, DEBUG_TYPE,static void *initializeLiveDebugVariablesPassOnce(PassRegistry
&Registry) {
77 "Debug Variable Analysis", false, false)static void *initializeLiveDebugVariablesPassOnce(PassRegistry
&Registry) {
78INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)initializeMachineDominatorTreePass(Registry);
79INITIALIZE_PASS_DEPENDENCY(LiveIntervals)initializeLiveIntervalsPass(Registry);
80INITIALIZE_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)); }
81 "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)); }
82
83void LiveDebugVariables::getAnalysisUsage(AnalysisUsage &AU) const {
84 AU.addRequired<MachineDominatorTree>();
85 AU.addRequiredTransitive<LiveIntervals>();
86 AU.setPreservesAll();
87 MachineFunctionPass::getAnalysisUsage(AU);
88}
89
90LiveDebugVariables::LiveDebugVariables() : MachineFunctionPass(ID) {
91 initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
92}
93
94enum : unsigned { UndefLocNo = ~0U };
95
96/// Describes a location by number along with some flags about the original
97/// usage of the location.
98class DbgValueLocation {
99public:
100 DbgValueLocation(unsigned LocNo, bool WasIndirect)
101 : LocNo(LocNo), WasIndirect(WasIndirect) {
102 static_assert(sizeof(*this) == sizeof(unsigned), "bad bitfield packing");
103 assert(locNo() == LocNo && "location truncation")(static_cast <bool> (locNo() == LocNo && "location truncation"
) ? void (0) : __assert_fail ("locNo() == LocNo && \"location truncation\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 103, __extension__ __PRETTY_FUNCTION__))
;
104 }
105
106 DbgValueLocation() : LocNo(0), WasIndirect(0) {}
107
108 unsigned locNo() const {
109 // Fix up the undef location number, which gets truncated.
110 return LocNo == INT_MAX2147483647 ? UndefLocNo : LocNo;
111 }
112 bool wasIndirect() const { return WasIndirect; }
113 bool isUndef() const { return locNo() == UndefLocNo; }
114
115 DbgValueLocation changeLocNo(unsigned NewLocNo) const {
116 return DbgValueLocation(NewLocNo, WasIndirect);
117 }
118
119 friend inline bool operator==(const DbgValueLocation &LHS,
120 const DbgValueLocation &RHS) {
121 return LHS.LocNo == RHS.LocNo && LHS.WasIndirect == RHS.WasIndirect;
122 }
123
124 friend inline bool operator!=(const DbgValueLocation &LHS,
125 const DbgValueLocation &RHS) {
126 return !(LHS == RHS);
127 }
128
129private:
130 unsigned LocNo : 31;
131 unsigned WasIndirect : 1;
132};
133
134/// LocMap - Map of where a user value is live, and its location.
135using LocMap = IntervalMap<SlotIndex, DbgValueLocation, 4>;
136
137namespace {
138
139class LDVImpl;
140
141/// UserValue - A user value is a part of a debug info user variable.
142///
143/// A DBG_VALUE instruction notes that (a sub-register of) a virtual register
144/// holds part of a user variable. The part is identified by a byte offset.
145///
146/// UserValues are grouped into equivalence classes for easier searching. Two
147/// user values are related if they refer to the same variable, or if they are
148/// held by the same virtual register. The equivalence class is the transitive
149/// closure of that relation.
150class UserValue {
151 const DILocalVariable *Variable; ///< The debug info variable we are part of.
152 const DIExpression *Expression; ///< Any complex address expression.
153 DebugLoc dl; ///< The debug location for the variable. This is
154 ///< used by dwarf writer to find lexical scope.
155 UserValue *leader; ///< Equivalence class leader.
156 UserValue *next = nullptr; ///< Next value in equivalence class, or null.
157
158 /// Numbered locations referenced by locmap.
159 SmallVector<MachineOperand, 4> locations;
160
161 /// Map of slot indices where this value is live.
162 LocMap locInts;
163
164 /// Set of interval start indexes that have been trimmed to the
165 /// lexical scope.
166 SmallSet<SlotIndex, 2> trimmedDefs;
167
168 /// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo.
169 void insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
170 SlotIndex StopIdx,
171 DbgValueLocation Loc, bool Spilled, LiveIntervals &LIS,
172 const TargetInstrInfo &TII,
173 const TargetRegisterInfo &TRI);
174
175 /// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs
176 /// is live. Returns true if any changes were made.
177 bool splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
178 LiveIntervals &LIS);
179
180public:
181 /// UserValue - Create a new UserValue.
182 UserValue(const DILocalVariable *var, const DIExpression *expr, DebugLoc L,
183 LocMap::Allocator &alloc)
184 : Variable(var), Expression(expr), dl(std::move(L)), leader(this),
185 locInts(alloc) {}
186
187 /// getLeader - Get the leader of this value's equivalence class.
188 UserValue *getLeader() {
189 UserValue *l = leader;
190 while (l != l->leader)
191 l = l->leader;
192 return leader = l;
193 }
194
195 /// getNext - Return the next UserValue in the equivalence class.
196 UserValue *getNext() const { return next; }
197
198 /// match - Does this UserValue match the parameters?
199 bool match(const DILocalVariable *Var, const DIExpression *Expr,
200 const DILocation *IA) const {
201 // FIXME: The fragment should be part of the equivalence class, but not
202 // other things in the expression like stack values.
203 return Var == Variable && Expr == Expression && dl->getInlinedAt() == IA;
204 }
205
206 /// merge - Merge equivalence classes.
207 static UserValue *merge(UserValue *L1, UserValue *L2) {
208 L2 = L2->getLeader();
209 if (!L1)
210 return L2;
211 L1 = L1->getLeader();
212 if (L1 == L2)
213 return L1;
214 // Splice L2 before L1's members.
215 UserValue *End = L2;
216 while (End->next) {
217 End->leader = L1;
218 End = End->next;
219 }
220 End->leader = L1;
221 End->next = L1->next;
222 L1->next = L2;
223 return L1;
224 }
225
226 /// getLocationNo - Return the location number that matches Loc.
227 unsigned getLocationNo(const MachineOperand &LocMO) {
228 if (LocMO.isReg()) {
229 if (LocMO.getReg() == 0)
230 return UndefLocNo;
231 // For register locations we dont care about use/def and other flags.
232 for (unsigned i = 0, e = locations.size(); i != e; ++i)
233 if (locations[i].isReg() &&
234 locations[i].getReg() == LocMO.getReg() &&
235 locations[i].getSubReg() == LocMO.getSubReg())
236 return i;
237 } else
238 for (unsigned i = 0, e = locations.size(); i != e; ++i)
239 if (LocMO.isIdenticalTo(locations[i]))
240 return i;
241 locations.push_back(LocMO);
242 // We are storing a MachineOperand outside a MachineInstr.
243 locations.back().clearParent();
244 // Don't store def operands.
245 if (locations.back().isReg()) {
246 if (locations.back().isDef())
247 locations.back().setIsDead(false);
248 locations.back().setIsUse();
249 }
250 return locations.size() - 1;
251 }
252
253 /// mapVirtRegs - Ensure that all virtual register locations are mapped.
254 void mapVirtRegs(LDVImpl *LDV);
255
256 /// addDef - Add a definition point to this value.
257 void addDef(SlotIndex Idx, const MachineOperand &LocMO, bool IsIndirect) {
258 DbgValueLocation Loc(getLocationNo(LocMO), IsIndirect);
259 // Add a singular (Idx,Idx) -> Loc mapping.
260 LocMap::iterator I = locInts.find(Idx);
261 if (!I.valid() || I.start() != Idx)
262 I.insert(Idx, Idx.getNextSlot(), Loc);
263 else
264 // A later DBG_VALUE at the same SlotIndex overrides the old location.
265 I.setValue(Loc);
266 }
267
268 /// extendDef - Extend the current definition as far as possible down.
269 /// Stop when meeting an existing def or when leaving the live
270 /// range of VNI.
271 /// End points where VNI is no longer live are added to Kills.
272 /// @param Idx Starting point for the definition.
273 /// @param Loc Location number to propagate.
274 /// @param LR Restrict liveness to where LR has the value VNI. May be null.
275 /// @param VNI When LR is not null, this is the value to restrict to.
276 /// @param Kills Append end points of VNI's live range to Kills.
277 /// @param LIS Live intervals analysis.
278 void extendDef(SlotIndex Idx, DbgValueLocation Loc,
279 LiveRange *LR, const VNInfo *VNI,
280 SmallVectorImpl<SlotIndex> *Kills,
281 LiveIntervals &LIS);
282
283 /// addDefsFromCopies - The value in LI/LocNo may be copies to other
284 /// registers. Determine if any of the copies are available at the kill
285 /// points, and add defs if possible.
286 /// @param LI Scan for copies of the value in LI->reg.
287 /// @param LocNo Location number of LI->reg.
288 /// @param WasIndirect Indicates if the original use of LI->reg was indirect
289 /// @param Kills Points where the range of LocNo could be extended.
290 /// @param NewDefs Append (Idx, LocNo) of inserted defs here.
291 void addDefsFromCopies(
292 LiveInterval *LI, unsigned LocNo, bool WasIndirect,
293 const SmallVectorImpl<SlotIndex> &Kills,
294 SmallVectorImpl<std::pair<SlotIndex, DbgValueLocation>> &NewDefs,
295 MachineRegisterInfo &MRI, LiveIntervals &LIS);
296
297 /// computeIntervals - Compute the live intervals of all locations after
298 /// collecting all their def points.
299 void computeIntervals(MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
300 LiveIntervals &LIS, LexicalScopes &LS);
301
302 /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
303 /// live. Returns true if any changes were made.
304 bool splitRegister(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
305 LiveIntervals &LIS);
306
307 /// rewriteLocations - Rewrite virtual register locations according to the
308 /// provided virtual register map. Record which locations were spilled.
309 void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI,
310 BitVector &SpilledLocations);
311
312 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
313 void emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
314 const TargetInstrInfo &TII,
315 const TargetRegisterInfo &TRI,
316 const BitVector &SpilledLocations);
317
318 /// getDebugLoc - Return DebugLoc of this UserValue.
319 DebugLoc getDebugLoc() { return dl;}
320
321 void print(raw_ostream &, const TargetRegisterInfo *);
322};
323
324/// LDVImpl - Implementation of the LiveDebugVariables pass.
325class LDVImpl {
326 LiveDebugVariables &pass;
327 LocMap::Allocator allocator;
328 MachineFunction *MF = nullptr;
329 LiveIntervals *LIS;
330 const TargetRegisterInfo *TRI;
331
332 /// Whether emitDebugValues is called.
333 bool EmitDone = false;
334
335 /// Whether the machine function is modified during the pass.
336 bool ModifiedMF = false;
337
338 /// userValues - All allocated UserValue instances.
339 SmallVector<std::unique_ptr<UserValue>, 8> userValues;
340
341 /// Map virtual register to eq class leader.
342 using VRMap = DenseMap<unsigned, UserValue *>;
343 VRMap virtRegToEqClass;
344
345 /// Map user variable to eq class leader.
346 using UVMap = DenseMap<const DILocalVariable *, UserValue *>;
347 UVMap userVarMap;
348
349 /// getUserValue - Find or create a UserValue.
350 UserValue *getUserValue(const DILocalVariable *Var, const DIExpression *Expr,
351 const DebugLoc &DL);
352
353 /// lookupVirtReg - Find the EC leader for VirtReg or null.
354 UserValue *lookupVirtReg(unsigned VirtReg);
355
356 /// handleDebugValue - Add DBG_VALUE instruction to our maps.
357 /// @param MI DBG_VALUE instruction
358 /// @param Idx Last valid SLotIndex before instruction.
359 /// @return True if the DBG_VALUE instruction should be deleted.
360 bool handleDebugValue(MachineInstr &MI, SlotIndex Idx);
361
362 /// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding
363 /// a UserValue def for each instruction.
364 /// @param mf MachineFunction to be scanned.
365 /// @return True if any debug values were found.
366 bool collectDebugValues(MachineFunction &mf);
367
368 /// computeIntervals - Compute the live intervals of all user values after
369 /// collecting all their def points.
370 void computeIntervals();
371
372public:
373 LDVImpl(LiveDebugVariables *ps) : pass(*ps) {}
374
375 bool runOnMachineFunction(MachineFunction &mf);
376
377 /// clear - Release all memory.
378 void clear() {
379 MF = nullptr;
380 userValues.clear();
381 virtRegToEqClass.clear();
382 userVarMap.clear();
383 // Make sure we call emitDebugValues if the machine function was modified.
384 assert((!ModifiedMF || EmitDone) &&(static_cast <bool> ((!ModifiedMF || EmitDone) &&
"Dbg values are not emitted in LDV") ? void (0) : __assert_fail
("(!ModifiedMF || EmitDone) && \"Dbg values are not emitted in LDV\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 385, __extension__ __PRETTY_FUNCTION__))
385 "Dbg values are not emitted in LDV")(static_cast <bool> ((!ModifiedMF || EmitDone) &&
"Dbg values are not emitted in LDV") ? void (0) : __assert_fail
("(!ModifiedMF || EmitDone) && \"Dbg values are not emitted in LDV\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 385, __extension__ __PRETTY_FUNCTION__))
;
386 EmitDone = false;
387 ModifiedMF = false;
388 }
389
390 /// mapVirtReg - Map virtual register to an equivalence class.
391 void mapVirtReg(unsigned VirtReg, UserValue *EC);
392
393 /// splitRegister - Replace all references to OldReg with NewRegs.
394 void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs);
395
396 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
397 void emitDebugValues(VirtRegMap *VRM);
398
399 void print(raw_ostream&);
400};
401
402} // end anonymous namespace
403
404#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
405static void printDebugLoc(const DebugLoc &DL, raw_ostream &CommentOS,
406 const LLVMContext &Ctx) {
407 if (!DL)
408 return;
409
410 auto *Scope = cast<DIScope>(DL.getScope());
411 // Omit the directory, because it's likely to be long and uninteresting.
412 CommentOS << Scope->getFilename();
413 CommentOS << ':' << DL.getLine();
414 if (DL.getCol() != 0)
415 CommentOS << ':' << DL.getCol();
416
417 DebugLoc InlinedAtDL = DL.getInlinedAt();
418 if (!InlinedAtDL)
419 return;
420
421 CommentOS << " @[ ";
422 printDebugLoc(InlinedAtDL, CommentOS, Ctx);
423 CommentOS << " ]";
424}
425
426static void printExtendedName(raw_ostream &OS, const DILocalVariable *V,
427 const DILocation *DL) {
428 const LLVMContext &Ctx = V->getContext();
429 StringRef Res = V->getName();
430 if (!Res.empty())
431 OS << Res << "," << V->getLine();
432 if (auto *InlinedAt = DL->getInlinedAt()) {
433 if (DebugLoc InlinedAtDL = InlinedAt) {
434 OS << " @[";
435 printDebugLoc(InlinedAtDL, OS, Ctx);
436 OS << "]";
437 }
438 }
439}
440
441void UserValue::print(raw_ostream &OS, const TargetRegisterInfo *TRI) {
442 auto *DV = cast<DILocalVariable>(Variable);
443 OS << "!\"";
444 printExtendedName(OS, DV, dl);
445
446 OS << "\"\t";
447 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
448 OS << " [" << I.start() << ';' << I.stop() << "):";
449 if (I.value().isUndef())
450 OS << "undef";
451 else {
452 OS << I.value().locNo();
453 if (I.value().wasIndirect())
454 OS << " ind";
455 }
456 }
457 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
458 OS << " Loc" << i << '=';
459 locations[i].print(OS, TRI);
460 }
461 OS << '\n';
462}
463
464void LDVImpl::print(raw_ostream &OS) {
465 OS << "********** DEBUG VARIABLES **********\n";
466 for (unsigned i = 0, e = userValues.size(); i != e; ++i)
467 userValues[i]->print(OS, TRI);
468}
469#endif
470
471void UserValue::mapVirtRegs(LDVImpl *LDV) {
472 for (unsigned i = 0, e = locations.size(); i != e; ++i)
473 if (locations[i].isReg() &&
474 TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
475 LDV->mapVirtReg(locations[i].getReg(), this);
476}
477
478UserValue *LDVImpl::getUserValue(const DILocalVariable *Var,
479 const DIExpression *Expr, const DebugLoc &DL) {
480 UserValue *&Leader = userVarMap[Var];
481 if (Leader) {
482 UserValue *UV = Leader->getLeader();
483 Leader = UV;
484 for (; UV; UV = UV->getNext())
485 if (UV->match(Var, Expr, DL->getInlinedAt()))
486 return UV;
487 }
488
489 userValues.push_back(
490 llvm::make_unique<UserValue>(Var, Expr, DL, allocator));
491 UserValue *UV = userValues.back().get();
492 Leader = UserValue::merge(Leader, UV);
493 return UV;
494}
495
496void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
497 assert(TargetRegisterInfo::isVirtualRegister(VirtReg) && "Only map VirtRegs")(static_cast <bool> (TargetRegisterInfo::isVirtualRegister
(VirtReg) && "Only map VirtRegs") ? void (0) : __assert_fail
("TargetRegisterInfo::isVirtualRegister(VirtReg) && \"Only map VirtRegs\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 497, __extension__ __PRETTY_FUNCTION__))
;
498 UserValue *&Leader = virtRegToEqClass[VirtReg];
499 Leader = UserValue::merge(Leader, EC);
500}
501
502UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
503 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
504 return UV->getLeader();
505 return nullptr;
506}
507
508bool LDVImpl::handleDebugValue(MachineInstr &MI, SlotIndex Idx) {
509 // DBG_VALUE loc, offset, variable
510 if (MI.getNumOperands() != 4 ||
511 !(MI.getOperand(1).isReg() || MI.getOperand(1).isImm()) ||
512 !MI.getOperand(2).isMetadata()) {
513 DEBUG(dbgs() << "Can't handle " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Can't handle " <<
MI; } } while (false)
;
514 return false;
515 }
516
517 // Detect invalid DBG_VALUE instructions, with a debug-use of a virtual
518 // register that hasn't been defined yet. If we do not remove those here, then
519 // the re-insertion of the DBG_VALUE instruction after register allocation
520 // will be incorrect.
521 // TODO: If earlier passes are corrected to generate sane debug information
522 // (and if the machine verifier is improved to catch this), then these checks
523 // could be removed or replaced by asserts.
524 bool Discard = false;
525 if (MI.getOperand(0).isReg() &&
526 TargetRegisterInfo::isVirtualRegister(MI.getOperand(0).getReg())) {
527 const unsigned Reg = MI.getOperand(0).getReg();
528 if (!LIS->hasInterval(Reg)) {
529 // The DBG_VALUE is described by a virtual register that does not have a
530 // live interval. Discard the DBG_VALUE.
531 Discard = true;
532 DEBUG(dbgs() << "Discarding debug info (no LIS interval): "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (no LIS interval): "
<< Idx << " " << MI; } } while (false)
533 << Idx << " " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (no LIS interval): "
<< Idx << " " << MI; } } while (false)
;
534 } else {
535 // The DBG_VALUE is only valid if either Reg is live out from Idx, or Reg
536 // is defined dead at Idx (where Idx is the slot index for the instruction
537 // preceeding the DBG_VALUE).
538 const LiveInterval &LI = LIS->getInterval(Reg);
539 LiveQueryResult LRQ = LI.Query(Idx);
540 if (!LRQ.valueOutOrDead()) {
541 // We have found a DBG_VALUE with the value in a virtual register that
542 // is not live. Discard the DBG_VALUE.
543 Discard = true;
544 DEBUG(dbgs() << "Discarding debug info (reg not live): "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (reg not live): "
<< Idx << " " << MI; } } while (false)
545 << Idx << " " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (reg not live): "
<< Idx << " " << MI; } } while (false)
;
546 }
547 }
548 }
549
550 // Get or create the UserValue for (variable,offset) here.
551 bool IsIndirect = MI.getOperand(1).isImm();
552 if (IsIndirect)
553 assert(MI.getOperand(1).getImm() == 0 && "DBG_VALUE with nonzero offset")(static_cast <bool> (MI.getOperand(1).getImm() == 0 &&
"DBG_VALUE with nonzero offset") ? void (0) : __assert_fail (
"MI.getOperand(1).getImm() == 0 && \"DBG_VALUE with nonzero offset\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 553, __extension__ __PRETTY_FUNCTION__))
;
554 const DILocalVariable *Var = MI.getDebugVariable();
555 const DIExpression *Expr = MI.getDebugExpression();
556 UserValue *UV =
557 getUserValue(Var, Expr, MI.getDebugLoc());
558 if (!Discard)
559 UV->addDef(Idx, MI.getOperand(0), IsIndirect);
560 else {
561 MachineOperand MO = MachineOperand::CreateReg(0U, false);
562 MO.setIsDebug();
563 UV->addDef(Idx, MO, false);
564 }
565 return true;
566}
567
568bool LDVImpl::collectDebugValues(MachineFunction &mf) {
569 bool Changed = false;
570 for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
571 ++MFI) {
572 MachineBasicBlock *MBB = &*MFI;
573 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
574 MBBI != MBBE;) {
575 if (!MBBI->isDebugValue()) {
576 ++MBBI;
577 continue;
578 }
579 // DBG_VALUE has no slot index, use the previous instruction instead.
580 SlotIndex Idx =
581 MBBI == MBB->begin()
582 ? LIS->getMBBStartIdx(MBB)
583 : LIS->getInstructionIndex(*std::prev(MBBI)).getRegSlot();
584 // Handle consecutive DBG_VALUE instructions with the same slot index.
585 do {
586 if (handleDebugValue(*MBBI, Idx)) {
587 MBBI = MBB->erase(MBBI);
588 Changed = true;
589 } else
590 ++MBBI;
591 } while (MBBI != MBBE && MBBI->isDebugValue());
592 }
593 }
594 return Changed;
595}
596
597/// We only propagate DBG_VALUES locally here. LiveDebugValues performs a
598/// data-flow analysis to propagate them beyond basic block boundaries.
599void UserValue::extendDef(SlotIndex Idx, DbgValueLocation Loc, LiveRange *LR,
600 const VNInfo *VNI, SmallVectorImpl<SlotIndex> *Kills,
601 LiveIntervals &LIS) {
602 SlotIndex Start = Idx;
603 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
604 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
605 LocMap::iterator I = locInts.find(Start);
606
607 // Limit to VNI's live range.
608 bool ToEnd = true;
609 if (LR && VNI) {
610 LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
611 if (!Segment || Segment->valno != VNI) {
612 if (Kills)
613 Kills->push_back(Start);
614 return;
615 }
616 if (Segment->end < Stop) {
617 Stop = Segment->end;
618 ToEnd = false;
619 }
620 }
621
622 // There could already be a short def at Start.
623 if (I.valid() && I.start() <= Start) {
624 // Stop when meeting a different location or an already extended interval.
625 Start = Start.getNextSlot();
626 if (I.value() != Loc || I.stop() != Start)
627 return;
628 // This is a one-slot placeholder. Just skip it.
629 ++I;
630 }
631
632 // Limited by the next def.
633 if (I.valid() && I.start() < Stop) {
634 Stop = I.start();
635 ToEnd = false;
Value stored to 'ToEnd' is never read
636 }
637 // Limited by VNI's live range.
638 else if (!ToEnd && Kills)
639 Kills->push_back(Stop);
640
641 if (Start < Stop)
642 I.insert(Start, Stop, Loc);
643}
644
645void UserValue::addDefsFromCopies(
646 LiveInterval *LI, unsigned LocNo, bool WasIndirect,
647 const SmallVectorImpl<SlotIndex> &Kills,
648 SmallVectorImpl<std::pair<SlotIndex, DbgValueLocation>> &NewDefs,
649 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
650 if (Kills.empty())
651 return;
652 // Don't track copies from physregs, there are too many uses.
653 if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
654 return;
655
656 // Collect all the (vreg, valno) pairs that are copies of LI.
657 SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
658 for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg)) {
659 MachineInstr *MI = MO.getParent();
660 // Copies of the full value.
661 if (MO.getSubReg() || !MI->isCopy())
662 continue;
663 unsigned DstReg = MI->getOperand(0).getReg();
664
665 // Don't follow copies to physregs. These are usually setting up call
666 // arguments, and the argument registers are always call clobbered. We are
667 // better off in the source register which could be a callee-saved register,
668 // or it could be spilled.
669 if (!TargetRegisterInfo::isVirtualRegister(DstReg))
670 continue;
671
672 // Is LocNo extended to reach this copy? If not, another def may be blocking
673 // it, or we are looking at a wrong value of LI.
674 SlotIndex Idx = LIS.getInstructionIndex(*MI);
675 LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
676 if (!I.valid() || I.value().locNo() != LocNo)
677 continue;
678
679 if (!LIS.hasInterval(DstReg))
680 continue;
681 LiveInterval *DstLI = &LIS.getInterval(DstReg);
682 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
683 assert(DstVNI && DstVNI->def == Idx.getRegSlot() && "Bad copy value")(static_cast <bool> (DstVNI && DstVNI->def ==
Idx.getRegSlot() && "Bad copy value") ? void (0) : __assert_fail
("DstVNI && DstVNI->def == Idx.getRegSlot() && \"Bad copy value\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 683, __extension__ __PRETTY_FUNCTION__))
;
684 CopyValues.push_back(std::make_pair(DstLI, DstVNI));
685 }
686
687 if (CopyValues.empty())
688 return;
689
690 DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Got " << CopyValues
.size() << " copies of " << *LI << '\n'; } }
while (false)
;
691
692 // Try to add defs of the copied values for each kill point.
693 for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
694 SlotIndex Idx = Kills[i];
695 for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
696 LiveInterval *DstLI = CopyValues[j].first;
697 const VNInfo *DstVNI = CopyValues[j].second;
698 if (DstLI->getVNInfoAt(Idx) != DstVNI)
699 continue;
700 // Check that there isn't already a def at Idx
701 LocMap::iterator I = locInts.find(Idx);
702 if (I.valid() && I.start() <= Idx)
703 continue;
704 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)
705 << 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)
;
706 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
707 assert(CopyMI && CopyMI->isCopy() && "Bad copy value")(static_cast <bool> (CopyMI && CopyMI->isCopy
() && "Bad copy value") ? void (0) : __assert_fail ("CopyMI && CopyMI->isCopy() && \"Bad copy value\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 707, __extension__ __PRETTY_FUNCTION__))
;
708 unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
709 DbgValueLocation NewLoc(LocNo, WasIndirect);
710 I.insert(Idx, Idx.getNextSlot(), NewLoc);
711 NewDefs.push_back(std::make_pair(Idx, NewLoc));
712 break;
713 }
714 }
715}
716
717void UserValue::computeIntervals(MachineRegisterInfo &MRI,
718 const TargetRegisterInfo &TRI,
719 LiveIntervals &LIS, LexicalScopes &LS) {
720 SmallVector<std::pair<SlotIndex, DbgValueLocation>, 16> Defs;
721
722 // Collect all defs to be extended (Skipping undefs).
723 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
724 if (!I.value().isUndef())
725 Defs.push_back(std::make_pair(I.start(), I.value()));
726
727 // Extend all defs, and possibly add new ones along the way.
728 for (unsigned i = 0; i != Defs.size(); ++i) {
729 SlotIndex Idx = Defs[i].first;
730 DbgValueLocation Loc = Defs[i].second;
731 const MachineOperand &LocMO = locations[Loc.locNo()];
732
733 if (!LocMO.isReg()) {
734 extendDef(Idx, Loc, nullptr, nullptr, nullptr, LIS);
735 continue;
736 }
737
738 // Register locations are constrained to where the register value is live.
739 if (TargetRegisterInfo::isVirtualRegister(LocMO.getReg())) {
740 LiveInterval *LI = nullptr;
741 const VNInfo *VNI = nullptr;
742 if (LIS.hasInterval(LocMO.getReg())) {
743 LI = &LIS.getInterval(LocMO.getReg());
744 VNI = LI->getVNInfoAt(Idx);
745 }
746 SmallVector<SlotIndex, 16> Kills;
747 extendDef(Idx, Loc, LI, VNI, &Kills, LIS);
748 if (LI)
749 addDefsFromCopies(LI, Loc.locNo(), Loc.wasIndirect(), Kills, Defs, MRI,
750 LIS);
751 continue;
752 }
753
754 // For physregs, we only mark the start slot idx. DwarfDebug will see it
755 // as if the DBG_VALUE is valid up until the end of the basic block, or
756 // the next def of the physical register. So we do not need to extend the
757 // range. It might actually happen that the DBG_VALUE is the last use of
758 // the physical register (e.g. if this is an unused input argument to a
759 // function).
760 }
761
762 // Erase all the undefs.
763 for (LocMap::iterator I = locInts.begin(); I.valid();)
764 if (I.value().isUndef())
765 I.erase();
766 else
767 ++I;
768
769 // The computed intervals may extend beyond the range of the debug
770 // location's lexical scope. In this case, splitting of an interval
771 // can result in an interval outside of the scope being created,
772 // causing extra unnecessary DBG_VALUEs to be emitted. To prevent
773 // this, trim the intervals to the lexical scope.
774
775 LexicalScope *Scope = LS.findLexicalScope(dl);
776 if (!Scope)
777 return;
778
779 SlotIndex PrevEnd;
780 LocMap::iterator I = locInts.begin();
781
782 // Iterate over the lexical scope ranges. Each time round the loop
783 // we check the intervals for overlap with the end of the previous
784 // range and the start of the next. The first range is handled as
785 // a special case where there is no PrevEnd.
786 for (const InsnRange &Range : Scope->getRanges()) {
787 SlotIndex RStart = LIS.getInstructionIndex(*Range.first);
788 SlotIndex REnd = LIS.getInstructionIndex(*Range.second);
789
790 // At the start of each iteration I has been advanced so that
791 // I.stop() >= PrevEnd. Check for overlap.
792 if (PrevEnd && I.start() < PrevEnd) {
793 SlotIndex IStop = I.stop();
794 DbgValueLocation Loc = I.value();
795
796 // Stop overlaps previous end - trim the end of the interval to
797 // the scope range.
798 I.setStopUnchecked(PrevEnd);
799 ++I;
800
801 // If the interval also overlaps the start of the "next" (i.e.
802 // current) range create a new interval for the remainder (which
803 // may be further trimmed).
804 if (RStart < IStop)
805 I.insert(RStart, IStop, Loc);
806 }
807
808 // Advance I so that I.stop() >= RStart, and check for overlap.
809 I.advanceTo(RStart);
810 if (!I.valid())
811 return;
812
813 if (I.start() < RStart) {
814 // Interval start overlaps range - trim to the scope range.
815 I.setStartUnchecked(RStart);
816 // Remember that this interval was trimmed.
817 trimmedDefs.insert(RStart);
818 }
819
820 // The end of a lexical scope range is the last instruction in the
821 // range. To convert to an interval we need the index of the
822 // instruction after it.
823 REnd = REnd.getNextIndex();
824
825 // Advance I to first interval outside current range.
826 I.advanceTo(REnd);
827 if (!I.valid())
828 return;
829
830 PrevEnd = REnd;
831 }
832
833 // Check for overlap with end of final range.
834 if (PrevEnd && I.start() < PrevEnd)
835 I.setStopUnchecked(PrevEnd);
836}
837
838void LDVImpl::computeIntervals() {
839 LexicalScopes LS;
840 LS.initialize(*MF);
841
842 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
843 userValues[i]->computeIntervals(MF->getRegInfo(), *TRI, *LIS, LS);
844 userValues[i]->mapVirtRegs(this);
845 }
846}
847
848bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
849 clear();
850 MF = &mf;
851 LIS = &pass.getAnalysis<LiveIntervals>();
852 TRI = mf.getSubtarget().getRegisterInfo();
853 DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
<< mf.getName() << " **********\n"; } } while (false
)
854 << mf.getName() << " **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
<< mf.getName() << " **********\n"; } } while (false
)
;
855
856 bool Changed = collectDebugValues(mf);
857 computeIntervals();
858 DEBUG(print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { print(dbgs()); } } while (false)
;
859 ModifiedMF = Changed;
860 return Changed;
861}
862
863static void removeDebugValues(MachineFunction &mf) {
864 for (MachineBasicBlock &MBB : mf) {
865 for (auto MBBI = MBB.begin(), MBBE = MBB.end(); MBBI != MBBE; ) {
866 if (!MBBI->isDebugValue()) {
867 ++MBBI;
868 continue;
869 }
870 MBBI = MBB.erase(MBBI);
871 }
872 }
873}
874
875bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
876 if (!EnableLDV)
877 return false;
878 if (!mf.getFunction().getSubprogram()) {
879 removeDebugValues(mf);
880 return false;
881 }
882 if (!pImpl)
883 pImpl = new LDVImpl(this);
884 return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
885}
886
887void LiveDebugVariables::releaseMemory() {
888 if (pImpl)
889 static_cast<LDVImpl*>(pImpl)->clear();
890}
891
892LiveDebugVariables::~LiveDebugVariables() {
893 if (pImpl)
894 delete static_cast<LDVImpl*>(pImpl);
895}
896
897//===----------------------------------------------------------------------===//
898// Live Range Splitting
899//===----------------------------------------------------------------------===//
900
901bool
902UserValue::splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
903 LiveIntervals& LIS) {
904 DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
905 dbgs() << "Splitting Loc" << OldLocNo << '\t';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
906 print(dbgs(), nullptr);do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
907 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
;
908 bool DidChange = false;
909 LocMap::iterator LocMapI;
910 LocMapI.setMap(locInts);
911 for (unsigned i = 0; i != NewRegs.size(); ++i) {
912 LiveInterval *LI = &LIS.getInterval(NewRegs[i]);
913 if (LI->empty())
914 continue;
915
916 // Don't allocate the new LocNo until it is needed.
917 unsigned NewLocNo = UndefLocNo;
918
919 // Iterate over the overlaps between locInts and LI.
920 LocMapI.find(LI->beginIndex());
921 if (!LocMapI.valid())
922 continue;
923 LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
924 LiveInterval::iterator LIE = LI->end();
925 while (LocMapI.valid() && LII != LIE) {
926 // At this point, we know that LocMapI.stop() > LII->start.
927 LII = LI->advanceTo(LII, LocMapI.start());
928 if (LII == LIE)
929 break;
930
931 // Now LII->end > LocMapI.start(). Do we have an overlap?
932 if (LocMapI.value().locNo() == OldLocNo && LII->start < LocMapI.stop()) {
933 // Overlapping correct location. Allocate NewLocNo now.
934 if (NewLocNo == UndefLocNo) {
935 MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
936 MO.setSubReg(locations[OldLocNo].getSubReg());
937 NewLocNo = getLocationNo(MO);
938 DidChange = true;
939 }
940
941 SlotIndex LStart = LocMapI.start();
942 SlotIndex LStop = LocMapI.stop();
943 DbgValueLocation OldLoc = LocMapI.value();
944
945 // Trim LocMapI down to the LII overlap.
946 if (LStart < LII->start)
947 LocMapI.setStartUnchecked(LII->start);
948 if (LStop > LII->end)
949 LocMapI.setStopUnchecked(LII->end);
950
951 // Change the value in the overlap. This may trigger coalescing.
952 LocMapI.setValue(OldLoc.changeLocNo(NewLocNo));
953
954 // Re-insert any removed OldLocNo ranges.
955 if (LStart < LocMapI.start()) {
956 LocMapI.insert(LStart, LocMapI.start(), OldLoc);
957 ++LocMapI;
958 assert(LocMapI.valid() && "Unexpected coalescing")(static_cast <bool> (LocMapI.valid() && "Unexpected coalescing"
) ? void (0) : __assert_fail ("LocMapI.valid() && \"Unexpected coalescing\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 958, __extension__ __PRETTY_FUNCTION__))
;
959 }
960 if (LStop > LocMapI.stop()) {
961 ++LocMapI;
962 LocMapI.insert(LII->end, LStop, OldLoc);
963 --LocMapI;
964 }
965 }
966
967 // Advance to the next overlap.
968 if (LII->end < LocMapI.stop()) {
969 if (++LII == LIE)
970 break;
971 LocMapI.advanceTo(LII->start);
972 } else {
973 ++LocMapI;
974 if (!LocMapI.valid())
975 break;
976 LII = LI->advanceTo(LII, LocMapI.start());
977 }
978 }
979 }
980
981 // Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
982 locations.erase(locations.begin() + OldLocNo);
983 LocMapI.goToBegin();
984 while (LocMapI.valid()) {
985 DbgValueLocation v = LocMapI.value();
986 if (v.locNo() == OldLocNo) {
987 DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Erasing [" << LocMapI
.start() << ';' << LocMapI.stop() << ")\n";
} } while (false)
988 << LocMapI.stop() << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Erasing [" << LocMapI
.start() << ';' << LocMapI.stop() << ")\n";
} } while (false)
;
989 LocMapI.erase();
990 } else {
991 if (v.locNo() > OldLocNo)
992 LocMapI.setValueUnchecked(v.changeLocNo(v.locNo() - 1));
993 ++LocMapI;
994 }
995 }
996
997 DEBUG({dbgs() << "Split result: \t"; print(dbgs(), nullptr);})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { {dbgs() << "Split result: \t"; print
(dbgs(), nullptr);}; } } while (false)
;
998 return DidChange;
999}
1000
1001bool
1002UserValue::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
1003 LiveIntervals &LIS) {
1004 bool DidChange = false;
1005 // Split locations referring to OldReg. Iterate backwards so splitLocation can
1006 // safely erase unused locations.
1007 for (unsigned i = locations.size(); i ; --i) {
1008 unsigned LocNo = i-1;
1009 const MachineOperand *Loc = &locations[LocNo];
1010 if (!Loc->isReg() || Loc->getReg() != OldReg)
1011 continue;
1012 DidChange |= splitLocation(LocNo, NewRegs, LIS);
1013 }
1014 return DidChange;
1015}
1016
1017void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs) {
1018 bool DidChange = false;
1019 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
1020 DidChange |= UV->splitRegister(OldReg, NewRegs, *LIS);
1021
1022 if (!DidChange)
1023 return;
1024
1025 // Map all of the new virtual registers.
1026 UserValue *UV = lookupVirtReg(OldReg);
1027 for (unsigned i = 0; i != NewRegs.size(); ++i)
1028 mapVirtReg(NewRegs[i], UV);
1029}
1030
1031void LiveDebugVariables::
1032splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, LiveIntervals &LIS) {
1033 if (pImpl)
1034 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
1035}
1036
1037void UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI,
1038 BitVector &SpilledLocations) {
1039 // Build a set of new locations with new numbers so we can coalesce our
1040 // IntervalMap if two vreg intervals collapse to the same physical location.
1041 // Use MapVector instead of SetVector because MapVector::insert returns the
1042 // position of the previously or newly inserted element. The boolean value
1043 // tracks if the location was produced by a spill.
1044 // FIXME: This will be problematic if we ever support direct and indirect
1045 // frame index locations, i.e. expressing both variables in memory and
1046 // 'int x, *px = &x'. The "spilled" bit must become part of the location.
1047 MapVector<MachineOperand, bool> NewLocations;
1048 SmallVector<unsigned, 4> LocNoMap(locations.size());
1049 for (unsigned I = 0, E = locations.size(); I != E; ++I) {
1050 bool Spilled = false;
1051 MachineOperand Loc = locations[I];
1052 // Only virtual registers are rewritten.
1053 if (Loc.isReg() && Loc.getReg() &&
1054 TargetRegisterInfo::isVirtualRegister(Loc.getReg())) {
1055 unsigned VirtReg = Loc.getReg();
1056 if (VRM.isAssignedReg(VirtReg) &&
1057 TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
1058 // This can create a %noreg operand in rare cases when the sub-register
1059 // index is no longer available. That means the user value is in a
1060 // non-existent sub-register, and %noreg is exactly what we want.
1061 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
1062 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
1063 // FIXME: Translate SubIdx to a stackslot offset.
1064 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
1065 Spilled = true;
1066 } else {
1067 Loc.setReg(0);
1068 Loc.setSubReg(0);
1069 }
1070 }
1071
1072 // Insert this location if it doesn't already exist and record a mapping
1073 // from the old number to the new number.
1074 auto InsertResult = NewLocations.insert({Loc, Spilled});
1075 unsigned NewLocNo = std::distance(NewLocations.begin(), InsertResult.first);
1076 LocNoMap[I] = NewLocNo;
1077 }
1078
1079 // Rewrite the locations and record which ones were spill slots.
1080 locations.clear();
1081 SpilledLocations.clear();
1082 SpilledLocations.resize(NewLocations.size());
1083 for (auto &Pair : NewLocations) {
1084 locations.push_back(Pair.first);
1085 if (Pair.second) {
1086 unsigned NewLocNo = std::distance(&*NewLocations.begin(), &Pair);
1087 SpilledLocations.set(NewLocNo);
1088 }
1089 }
1090
1091 // Update the interval map, but only coalesce left, since intervals to the
1092 // right use the old location numbers. This should merge two contiguous
1093 // DBG_VALUE intervals with different vregs that were allocated to the same
1094 // physical register.
1095 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
1096 DbgValueLocation Loc = I.value();
1097 unsigned NewLocNo = LocNoMap[Loc.locNo()];
1098 I.setValueUnchecked(Loc.changeLocNo(NewLocNo));
1099 I.setStart(I.start());
1100 }
1101}
1102
1103/// Find an iterator for inserting a DBG_VALUE instruction.
1104static MachineBasicBlock::iterator
1105findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
1106 LiveIntervals &LIS) {
1107 SlotIndex Start = LIS.getMBBStartIdx(MBB);
1108 Idx = Idx.getBaseIndex();
1109
1110 // Try to find an insert location by going backwards from Idx.
1111 MachineInstr *MI;
1112 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
1113 // We've reached the beginning of MBB.
1114 if (Idx == Start) {
1115 MachineBasicBlock::iterator I = MBB->SkipPHIsLabelsAndDebug(MBB->begin());
1116 return I;
1117 }
1118 Idx = Idx.getPrevIndex();
1119 }
1120
1121 // Don't insert anything after the first terminator, though.
1122 return MI->isTerminator() ? MBB->getFirstTerminator() :
1123 std::next(MachineBasicBlock::iterator(MI));
1124}
1125
1126/// Find an iterator for inserting the next DBG_VALUE instruction
1127/// (or end if no more insert locations found).
1128static MachineBasicBlock::iterator
1129findNextInsertLocation(MachineBasicBlock *MBB,
1130 MachineBasicBlock::iterator I,
1131 SlotIndex StopIdx, MachineOperand &LocMO,
1132 LiveIntervals &LIS,
1133 const TargetRegisterInfo &TRI) {
1134 if (!LocMO.isReg())
1135 return MBB->instr_end();
1136 unsigned Reg = LocMO.getReg();
1137
1138 // Find the next instruction in the MBB that define the register Reg.
1139 while (I != MBB->end() && !I->isTerminator()) {
1140 if (!LIS.isNotInMIMap(*I) &&
1141 SlotIndex::isEarlierEqualInstr(StopIdx, LIS.getInstructionIndex(*I)))
1142 break;
1143 if (I->definesRegister(Reg, &TRI))
1144 // The insert location is directly after the instruction/bundle.
1145 return std::next(I);
1146 ++I;
1147 }
1148 return MBB->end();
1149}
1150
1151void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
1152 SlotIndex StopIdx,
1153 DbgValueLocation Loc, bool Spilled,
1154 LiveIntervals &LIS,
1155 const TargetInstrInfo &TII,
1156 const TargetRegisterInfo &TRI) {
1157 SlotIndex MBBEndIdx = LIS.getMBBEndIdx(&*MBB);
1158 // Only search within the current MBB.
1159 StopIdx = (MBBEndIdx < StopIdx) ? MBBEndIdx : StopIdx;
1160 MachineBasicBlock::iterator I = findInsertLocation(MBB, StartIdx, LIS);
1161 MachineOperand &MO = locations[Loc.locNo()];
1162 ++NumInsertedDebugValues;
1163
1164 assert(cast<DILocalVariable>(Variable)(static_cast <bool> (cast<DILocalVariable>(Variable
) ->isValidLocationForIntrinsic(getDebugLoc()) && "Expected inlined-at fields to agree"
) ? void (0) : __assert_fail ("cast<DILocalVariable>(Variable) ->isValidLocationForIntrinsic(getDebugLoc()) && \"Expected inlined-at fields to agree\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 1166, __extension__ __PRETTY_FUNCTION__))
1165 ->isValidLocationForIntrinsic(getDebugLoc()) &&(static_cast <bool> (cast<DILocalVariable>(Variable
) ->isValidLocationForIntrinsic(getDebugLoc()) && "Expected inlined-at fields to agree"
) ? void (0) : __assert_fail ("cast<DILocalVariable>(Variable) ->isValidLocationForIntrinsic(getDebugLoc()) && \"Expected inlined-at fields to agree\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 1166, __extension__ __PRETTY_FUNCTION__))
1166 "Expected inlined-at fields to agree")(static_cast <bool> (cast<DILocalVariable>(Variable
) ->isValidLocationForIntrinsic(getDebugLoc()) && "Expected inlined-at fields to agree"
) ? void (0) : __assert_fail ("cast<DILocalVariable>(Variable) ->isValidLocationForIntrinsic(getDebugLoc()) && \"Expected inlined-at fields to agree\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 1166, __extension__ __PRETTY_FUNCTION__))
;
1167
1168 // If the location was spilled, the new DBG_VALUE will be indirect. If the
1169 // original DBG_VALUE was indirect, we need to add DW_OP_deref to indicate
1170 // that the original virtual register was a pointer.
1171 const DIExpression *Expr = Expression;
1172 bool IsIndirect = Loc.wasIndirect();
1173 if (Spilled) {
1174 if (IsIndirect)
1175 Expr = DIExpression::prepend(Expr, DIExpression::WithDeref);
1176 IsIndirect = true;
1177 }
1178
1179 assert((!Spilled || MO.isFI()) && "a spilled location must be a frame index")(static_cast <bool> ((!Spilled || MO.isFI()) &&
"a spilled location must be a frame index") ? void (0) : __assert_fail
("(!Spilled || MO.isFI()) && \"a spilled location must be a frame index\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/CodeGen/LiveDebugVariables.cpp"
, 1179, __extension__ __PRETTY_FUNCTION__))
;
1180
1181 do {
1182 MachineInstrBuilder MIB =
1183 BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
1184 .add(MO);
1185 if (IsIndirect)
1186 MIB.addImm(0U);
1187 else
1188 MIB.addReg(0U, RegState::Debug);
1189 MIB.addMetadata(Variable).addMetadata(Expr);
1190
1191 // Continue and insert DBG_VALUES after every redefinition of register
1192 // associated with the debug value within the range
1193 I = findNextInsertLocation(MBB, I, StopIdx, MO, LIS, TRI);
1194 } while (I != MBB->end());
1195}
1196
1197void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
1198 const TargetInstrInfo &TII,
1199 const TargetRegisterInfo &TRI,
1200 const BitVector &SpilledLocations) {
1201 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
1202
1203 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
1204 SlotIndex Start = I.start();
1205 SlotIndex Stop = I.stop();
1206 DbgValueLocation Loc = I.value();
1207 bool Spilled = !Loc.isUndef() ? SpilledLocations.test(Loc.locNo()) : false;
1208
1209 // If the interval start was trimmed to the lexical scope insert the
1210 // DBG_VALUE at the previous index (otherwise it appears after the
1211 // first instruction in the range).
1212 if (trimmedDefs.count(Start))
1213 Start = Start.getPrevIndex();
1214
1215 DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << Loc.locNo())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "\t[" << Start <<
';' << Stop << "):" << Loc.locNo(); } } while
(false)
;
1216 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start)->getIterator();
1217 SlotIndex MBBEnd = LIS.getMBBEndIdx(&*MBB);
1218
1219 DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB) << '-' << MBBEnd; } } while (false)
;
1220 insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, LIS, TII, TRI);
1221 // This interval may span multiple basic blocks.
1222 // Insert a DBG_VALUE into each one.
1223 while (Stop > MBBEnd) {
1224 // Move to the next block.
1225 Start = MBBEnd;
1226 if (++MBB == MFEnd)
1227 break;
1228 MBBEnd = LIS.getMBBEndIdx(&*MBB);
1229 DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB) << '-' << MBBEnd; } } while (false)
;
1230 insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, LIS, TII, TRI);
1231 }
1232 DEBUG(dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << '\n'; } } while (false)
;
1233 if (MBB == MFEnd)
1234 break;
1235
1236 ++I;
1237 }
1238}
1239
1240void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
1241 DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n"
; } } while (false)
;
1242 if (!MF)
1243 return;
1244 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
1245 BitVector SpilledLocations;
1246 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
1247 DEBUG(userValues[i]->print(dbgs(), TRI))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { userValues[i]->print(dbgs(), TRI); } }
while (false)
;
1248 userValues[i]->rewriteLocations(*VRM, *TRI, SpilledLocations);
1249 userValues[i]->emitDebugValues(VRM, *LIS, *TII, *TRI, SpilledLocations);
1250 }
1251 EmitDone = true;
1252}
1253
1254void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
1255 if (pImpl)
1256 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
1257}
1258
1259bool LiveDebugVariables::doInitialization(Module &M) {
1260 return Pass::doInitialization(M);
1261}
1262
1263#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1264LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void LiveDebugVariables::dump() const {
1265 if (pImpl)
1266 static_cast<LDVImpl*>(pImpl)->print(dbgs());
1267}
1268#endif