Bug Summary

File:lib/CodeGen/LiveDebugVariables.cpp
Warning:line 653, 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 -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~svn345461/build-llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-8~svn345461/lib/CodeGen -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/include -I /build/llvm-toolchain-snapshot-8~svn345461/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~svn345461/build-llvm/lib/CodeGen -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-10-27-211344-32123-1 -x c++ /build/llvm-toolchain-snapshot-8~svn345461/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~svn345461/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/// LocMap - Map of where a user value is live, and its location.
136using LocMap = IntervalMap<SlotIndex, DbgValueLocation, 4>;
137
138/// SpillOffsetMap - 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/// UserValue - 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 /// insertDebugValue - 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 /// splitLocation - 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 /// UserValue - 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 /// getLeader - 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 /// getNext - Return the next UserValue in the equivalence class.
201 UserValue *getNext() const { return next; }
202
203 /// match - 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 - 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 /// mapVirtRegs - Ensure that all virtual register locations are mapped.
264 void mapVirtRegs(LDVImpl *LDV);
265
266 /// addDef - 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 /// extendDef - Extend the current definition as far as possible down.
279 /// Stop when meeting an existing def or when leaving the live
280 /// range of VNI.
281 /// End points where VNI is no longer live are added to Kills.
282 /// @param Idx Starting point for the definition.
283 /// @param Loc Location number to propagate.
284 /// @param LR Restrict liveness to where LR has the value VNI. May be null.
285 /// @param VNI When LR is not null, this is the value to restrict to.
286 /// @param Kills Append end points of VNI's live range to Kills.
287 /// @param LIS Live intervals analysis.
288 void extendDef(SlotIndex Idx, DbgValueLocation Loc,
289 LiveRange *LR, const VNInfo *VNI,
290 SmallVectorImpl<SlotIndex> *Kills,
291 LiveIntervals &LIS);
292
293 /// addDefsFromCopies - The value in LI/LocNo may be copies to other
294 /// registers. Determine if any of the copies are available at the kill
295 /// points, and add defs if possible.
296 /// @param LI Scan for copies of the value in LI->reg.
297 /// @param LocNo Location number of LI->reg.
298 /// @param WasIndirect Indicates if the original use of LI->reg was indirect
299 /// @param Kills Points where the range of LocNo could be extended.
300 /// @param NewDefs Append (Idx, LocNo) of inserted defs here.
301 void addDefsFromCopies(
302 LiveInterval *LI, unsigned LocNo, bool WasIndirect,
303 const SmallVectorImpl<SlotIndex> &Kills,
304 SmallVectorImpl<std::pair<SlotIndex, DbgValueLocation>> &NewDefs,
305 MachineRegisterInfo &MRI, LiveIntervals &LIS);
306
307 /// computeIntervals - Compute the live intervals of all locations after
308 /// collecting all their def points.
309 void computeIntervals(MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
310 LiveIntervals &LIS, LexicalScopes &LS);
311
312 /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
313 /// live. Returns true if any changes were made.
314 bool splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
315 LiveIntervals &LIS);
316
317 /// rewriteLocations - Rewrite virtual register locations according to the
318 /// provided virtual register map. Record the stack slot offsets for the
319 /// locations that were spilled.
320 void rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF,
321 const TargetInstrInfo &TII,
322 const TargetRegisterInfo &TRI,
323 SpillOffsetMap &SpillOffsets);
324
325 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
326 void emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
327 const TargetInstrInfo &TII,
328 const TargetRegisterInfo &TRI,
329 const SpillOffsetMap &SpillOffsets);
330
331 /// getDebugLoc - Return DebugLoc of this UserValue.
332 DebugLoc getDebugLoc() { return dl;}
333
334 void print(raw_ostream &, const TargetRegisterInfo *);
335};
336
337/// LDVImpl - Implementation of the LiveDebugVariables pass.
338class LDVImpl {
339 LiveDebugVariables &pass;
340 LocMap::Allocator allocator;
341 MachineFunction *MF = nullptr;
342 LiveIntervals *LIS;
343 const TargetRegisterInfo *TRI;
344
345 /// Whether emitDebugValues is called.
346 bool EmitDone = false;
347
348 /// Whether the machine function is modified during the pass.
349 bool ModifiedMF = false;
350
351 /// userValues - All allocated UserValue instances.
352 SmallVector<std::unique_ptr<UserValue>, 8> userValues;
353
354 /// Map virtual register to eq class leader.
355 using VRMap = DenseMap<unsigned, UserValue *>;
356 VRMap virtRegToEqClass;
357
358 /// Map user variable to eq class leader.
359 using UVMap = DenseMap<const DILocalVariable *, UserValue *>;
360 UVMap userVarMap;
361
362 /// getUserValue - Find or create a UserValue.
363 UserValue *getUserValue(const DILocalVariable *Var, const DIExpression *Expr,
364 const DebugLoc &DL);
365
366 /// lookupVirtReg - Find the EC leader for VirtReg or null.
367 UserValue *lookupVirtReg(unsigned VirtReg);
368
369 /// handleDebugValue - Add DBG_VALUE instruction to our maps.
370 /// @param MI DBG_VALUE instruction
371 /// @param Idx Last valid SLotIndex before instruction.
372 /// @return True if the DBG_VALUE instruction should be deleted.
373 bool handleDebugValue(MachineInstr &MI, SlotIndex Idx);
374
375 /// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding
376 /// a UserValue def for each instruction.
377 /// @param mf MachineFunction to be scanned.
378 /// @return True if any debug values were found.
379 bool collectDebugValues(MachineFunction &mf);
380
381 /// computeIntervals - Compute the live intervals of all user values after
382 /// collecting all their def points.
383 void computeIntervals();
384
385public:
386 LDVImpl(LiveDebugVariables *ps) : pass(*ps) {}
387
388 bool runOnMachineFunction(MachineFunction &mf);
389
390 /// clear - Release all memory.
391 void clear() {
392 MF = nullptr;
393 userValues.clear();
394 virtRegToEqClass.clear();
395 userVarMap.clear();
396 // Make sure we call emitDebugValues if the machine function was modified.
397 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~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 398, __PRETTY_FUNCTION__))
398 "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~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 398, __PRETTY_FUNCTION__))
;
399 EmitDone = false;
400 ModifiedMF = false;
401 }
402
403 /// mapVirtReg - Map virtual register to an equivalence class.
404 void mapVirtReg(unsigned VirtReg, UserValue *EC);
405
406 /// splitRegister - Replace all references to OldReg with NewRegs.
407 void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs);
408
409 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
410 void emitDebugValues(VirtRegMap *VRM);
411
412 void print(raw_ostream&);
413};
414
415} // end anonymous namespace
416
417#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
418static void printDebugLoc(const DebugLoc &DL, raw_ostream &CommentOS,
419 const LLVMContext &Ctx) {
420 if (!DL)
421 return;
422
423 auto *Scope = cast<DIScope>(DL.getScope());
424 // Omit the directory, because it's likely to be long and uninteresting.
425 CommentOS << Scope->getFilename();
426 CommentOS << ':' << DL.getLine();
427 if (DL.getCol() != 0)
428 CommentOS << ':' << DL.getCol();
429
430 DebugLoc InlinedAtDL = DL.getInlinedAt();
431 if (!InlinedAtDL)
432 return;
433
434 CommentOS << " @[ ";
435 printDebugLoc(InlinedAtDL, CommentOS, Ctx);
436 CommentOS << " ]";
437}
438
439static void printExtendedName(raw_ostream &OS, const DILocalVariable *V,
440 const DILocation *DL) {
441 const LLVMContext &Ctx = V->getContext();
442 StringRef Res = V->getName();
443 if (!Res.empty())
444 OS << Res << "," << V->getLine();
445 if (auto *InlinedAt = DL->getInlinedAt()) {
446 if (DebugLoc InlinedAtDL = InlinedAt) {
447 OS << " @[";
448 printDebugLoc(InlinedAtDL, OS, Ctx);
449 OS << "]";
450 }
451 }
452}
453
454void UserValue::print(raw_ostream &OS, const TargetRegisterInfo *TRI) {
455 auto *DV = cast<DILocalVariable>(Variable);
456 OS << "!\"";
457 printExtendedName(OS, DV, dl);
458
459 OS << "\"\t";
460 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
461 OS << " [" << I.start() << ';' << I.stop() << "):";
462 if (I.value().isUndef())
463 OS << "undef";
464 else {
465 OS << I.value().locNo();
466 if (I.value().wasIndirect())
467 OS << " ind";
468 }
469 }
470 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
471 OS << " Loc" << i << '=';
472 locations[i].print(OS, TRI);
473 }
474 OS << '\n';
475}
476
477void LDVImpl::print(raw_ostream &OS) {
478 OS << "********** DEBUG VARIABLES **********\n";
479 for (unsigned i = 0, e = userValues.size(); i != e; ++i)
480 userValues[i]->print(OS, TRI);
481}
482#endif
483
484void UserValue::mapVirtRegs(LDVImpl *LDV) {
485 for (unsigned i = 0, e = locations.size(); i != e; ++i)
486 if (locations[i].isReg() &&
487 TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
488 LDV->mapVirtReg(locations[i].getReg(), this);
489}
490
491UserValue *LDVImpl::getUserValue(const DILocalVariable *Var,
492 const DIExpression *Expr, const DebugLoc &DL) {
493 UserValue *&Leader = userVarMap[Var];
494 if (Leader) {
495 UserValue *UV = Leader->getLeader();
496 Leader = UV;
497 for (; UV; UV = UV->getNext())
498 if (UV->match(Var, Expr, DL->getInlinedAt()))
499 return UV;
500 }
501
502 userValues.push_back(
503 llvm::make_unique<UserValue>(Var, Expr, DL, allocator));
504 UserValue *UV = userValues.back().get();
505 Leader = UserValue::merge(Leader, UV);
506 return UV;
507}
508
509void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
510 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~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 510, __PRETTY_FUNCTION__))
;
511 UserValue *&Leader = virtRegToEqClass[VirtReg];
512 Leader = UserValue::merge(Leader, EC);
513}
514
515UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
516 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
517 return UV->getLeader();
518 return nullptr;
519}
520
521bool LDVImpl::handleDebugValue(MachineInstr &MI, SlotIndex Idx) {
522 // DBG_VALUE loc, offset, variable
523 if (MI.getNumOperands() != 4 ||
524 !(MI.getOperand(1).isReg() || MI.getOperand(1).isImm()) ||
525 !MI.getOperand(2).isMetadata()) {
526 LLVM_DEBUG(dbgs() << "Can't handle " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Can't handle " <<
MI; } } while (false)
;
527 return false;
528 }
529
530 // Detect invalid DBG_VALUE instructions, with a debug-use of a virtual
531 // register that hasn't been defined yet. If we do not remove those here, then
532 // the re-insertion of the DBG_VALUE instruction after register allocation
533 // will be incorrect.
534 // TODO: If earlier passes are corrected to generate sane debug information
535 // (and if the machine verifier is improved to catch this), then these checks
536 // could be removed or replaced by asserts.
537 bool Discard = false;
538 if (MI.getOperand(0).isReg() &&
539 TargetRegisterInfo::isVirtualRegister(MI.getOperand(0).getReg())) {
540 const unsigned Reg = MI.getOperand(0).getReg();
541 if (!LIS->hasInterval(Reg)) {
542 // The DBG_VALUE is described by a virtual register that does not have a
543 // live interval. Discard the DBG_VALUE.
544 Discard = true;
545 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)
546 << " " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (no LIS interval): "
<< Idx << " " << MI; } } while (false)
;
547 } else {
548 // The DBG_VALUE is only valid if either Reg is live out from Idx, or Reg
549 // is defined dead at Idx (where Idx is the slot index for the instruction
550 // preceeding the DBG_VALUE).
551 const LiveInterval &LI = LIS->getInterval(Reg);
552 LiveQueryResult LRQ = LI.Query(Idx);
553 if (!LRQ.valueOutOrDead()) {
554 // We have found a DBG_VALUE with the value in a virtual register that
555 // is not live. Discard the DBG_VALUE.
556 Discard = true;
557 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)
558 << " " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (reg not live): "
<< Idx << " " << MI; } } while (false)
;
559 }
560 }
561 }
562
563 // Get or create the UserValue for (variable,offset) here.
564 bool IsIndirect = MI.getOperand(1).isImm();
565 if (IsIndirect)
566 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~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 566, __PRETTY_FUNCTION__))
;
567 const DILocalVariable *Var = MI.getDebugVariable();
568 const DIExpression *Expr = MI.getDebugExpression();
569 UserValue *UV =
570 getUserValue(Var, Expr, MI.getDebugLoc());
571 if (!Discard)
572 UV->addDef(Idx, MI.getOperand(0), IsIndirect);
573 else {
574 MachineOperand MO = MachineOperand::CreateReg(0U, false);
575 MO.setIsDebug();
576 UV->addDef(Idx, MO, false);
577 }
578 return true;
579}
580
581bool LDVImpl::collectDebugValues(MachineFunction &mf) {
582 bool Changed = false;
583 for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
584 ++MFI) {
585 MachineBasicBlock *MBB = &*MFI;
586 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
587 MBBI != MBBE;) {
588 // Use the first debug instruction in the sequence to get a SlotIndex
589 // for following consecutive debug instructions.
590 if (!MBBI->isDebugInstr()) {
591 ++MBBI;
592 continue;
593 }
594 // Debug instructions has no slot index. Use the previous
595 // non-debug instruction's SlotIndex as its SlotIndex.
596 SlotIndex Idx =
597 MBBI == MBB->begin()
598 ? LIS->getMBBStartIdx(MBB)
599 : LIS->getInstructionIndex(*std::prev(MBBI)).getRegSlot();
600 // Handle consecutive debug instructions with the same slot index.
601 do {
602 // Only handle DBG_VALUE in handleDebugValue(). Skip all other
603 // kinds of debug instructions.
604 if (MBBI->isDebugValue() && handleDebugValue(*MBBI, Idx)) {
605 MBBI = MBB->erase(MBBI);
606 Changed = true;
607 } else
608 ++MBBI;
609 } while (MBBI != MBBE && MBBI->isDebugInstr());
610 }
611 }
612 return Changed;
613}
614
615/// We only propagate DBG_VALUES locally here. LiveDebugValues performs a
616/// data-flow analysis to propagate them beyond basic block boundaries.
617void UserValue::extendDef(SlotIndex Idx, DbgValueLocation Loc, LiveRange *LR,
618 const VNInfo *VNI, SmallVectorImpl<SlotIndex> *Kills,
619 LiveIntervals &LIS) {
620 SlotIndex Start = Idx;
621 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
622 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
623 LocMap::iterator I = locInts.find(Start);
624
625 // Limit to VNI's live range.
626 bool ToEnd = true;
627 if (LR && VNI) {
628 LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
629 if (!Segment || Segment->valno != VNI) {
630 if (Kills)
631 Kills->push_back(Start);
632 return;
633 }
634 if (Segment->end < Stop) {
635 Stop = Segment->end;
636 ToEnd = false;
637 }
638 }
639
640 // There could already be a short def at Start.
641 if (I.valid() && I.start() <= Start) {
642 // Stop when meeting a different location or an already extended interval.
643 Start = Start.getNextSlot();
644 if (I.value() != Loc || I.stop() != Start)
645 return;
646 // This is a one-slot placeholder. Just skip it.
647 ++I;
648 }
649
650 // Limited by the next def.
651 if (I.valid() && I.start() < Stop) {
652 Stop = I.start();
653 ToEnd = false;
Value stored to 'ToEnd' is never read
654 }
655 // Limited by VNI's live range.
656 else if (!ToEnd && Kills)
657 Kills->push_back(Stop);
658
659 if (Start < Stop)
660 I.insert(Start, Stop, Loc);
661}
662
663void UserValue::addDefsFromCopies(
664 LiveInterval *LI, unsigned LocNo, bool WasIndirect,
665 const SmallVectorImpl<SlotIndex> &Kills,
666 SmallVectorImpl<std::pair<SlotIndex, DbgValueLocation>> &NewDefs,
667 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
668 if (Kills.empty())
669 return;
670 // Don't track copies from physregs, there are too many uses.
671 if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
672 return;
673
674 // Collect all the (vreg, valno) pairs that are copies of LI.
675 SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
676 for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg)) {
677 MachineInstr *MI = MO.getParent();
678 // Copies of the full value.
679 if (MO.getSubReg() || !MI->isCopy())
680 continue;
681 unsigned DstReg = MI->getOperand(0).getReg();
682
683 // Don't follow copies to physregs. These are usually setting up call
684 // arguments, and the argument registers are always call clobbered. We are
685 // better off in the source register which could be a callee-saved register,
686 // or it could be spilled.
687 if (!TargetRegisterInfo::isVirtualRegister(DstReg))
688 continue;
689
690 // Is LocNo extended to reach this copy? If not, another def may be blocking
691 // it, or we are looking at a wrong value of LI.
692 SlotIndex Idx = LIS.getInstructionIndex(*MI);
693 LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
694 if (!I.valid() || I.value().locNo() != LocNo)
695 continue;
696
697 if (!LIS.hasInterval(DstReg))
698 continue;
699 LiveInterval *DstLI = &LIS.getInterval(DstReg);
700 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
701 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~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 701, __PRETTY_FUNCTION__))
;
702 CopyValues.push_back(std::make_pair(DstLI, DstVNI));
703 }
704
705 if (CopyValues.empty())
706 return;
707
708 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)
709 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Got " << CopyValues
.size() << " copies of " << *LI << '\n'; } }
while (false)
;
710
711 // Try to add defs of the copied values for each kill point.
712 for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
713 SlotIndex Idx = Kills[i];
714 for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
715 LiveInterval *DstLI = CopyValues[j].first;
716 const VNInfo *DstVNI = CopyValues[j].second;
717 if (DstLI->getVNInfoAt(Idx) != DstVNI)
718 continue;
719 // Check that there isn't already a def at Idx
720 LocMap::iterator I = locInts.find(Idx);
721 if (I.valid() && I.start() <= Idx)
722 continue;
723 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)
724 << 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)
;
725 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
726 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~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 726, __PRETTY_FUNCTION__))
;
727 unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
728 DbgValueLocation NewLoc(LocNo, WasIndirect);
729 I.insert(Idx, Idx.getNextSlot(), NewLoc);
730 NewDefs.push_back(std::make_pair(Idx, NewLoc));
731 break;
732 }
733 }
734}
735
736void UserValue::computeIntervals(MachineRegisterInfo &MRI,
737 const TargetRegisterInfo &TRI,
738 LiveIntervals &LIS, LexicalScopes &LS) {
739 SmallVector<std::pair<SlotIndex, DbgValueLocation>, 16> Defs;
740
741 // Collect all defs to be extended (Skipping undefs).
742 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
743 if (!I.value().isUndef())
744 Defs.push_back(std::make_pair(I.start(), I.value()));
745
746 // Extend all defs, and possibly add new ones along the way.
747 for (unsigned i = 0; i != Defs.size(); ++i) {
748 SlotIndex Idx = Defs[i].first;
749 DbgValueLocation Loc = Defs[i].second;
750 const MachineOperand &LocMO = locations[Loc.locNo()];
751
752 if (!LocMO.isReg()) {
753 extendDef(Idx, Loc, nullptr, nullptr, nullptr, LIS);
754 continue;
755 }
756
757 // Register locations are constrained to where the register value is live.
758 if (TargetRegisterInfo::isVirtualRegister(LocMO.getReg())) {
759 LiveInterval *LI = nullptr;
760 const VNInfo *VNI = nullptr;
761 if (LIS.hasInterval(LocMO.getReg())) {
762 LI = &LIS.getInterval(LocMO.getReg());
763 VNI = LI->getVNInfoAt(Idx);
764 }
765 SmallVector<SlotIndex, 16> Kills;
766 extendDef(Idx, Loc, LI, VNI, &Kills, LIS);
767 // FIXME: Handle sub-registers in addDefsFromCopies. The problem is that
768 // if the original location for example is %vreg0:sub_hi, and we find a
769 // full register copy in addDefsFromCopies (at the moment it only handles
770 // full register copies), then we must add the sub1 sub-register index to
771 // the new location. However, that is only possible if the new virtual
772 // register is of the same regclass (or if there is an equivalent
773 // sub-register in that regclass). For now, simply skip handling copies if
774 // a sub-register is involved.
775 if (LI && !LocMO.getSubReg())
776 addDefsFromCopies(LI, Loc.locNo(), Loc.wasIndirect(), Kills, Defs, MRI,
777 LIS);
778 continue;
779 }
780
781 // For physregs, we only mark the start slot idx. DwarfDebug will see it
782 // as if the DBG_VALUE is valid up until the end of the basic block, or
783 // the next def of the physical register. So we do not need to extend the
784 // range. It might actually happen that the DBG_VALUE is the last use of
785 // the physical register (e.g. if this is an unused input argument to a
786 // function).
787 }
788
789 // The computed intervals may extend beyond the range of the debug
790 // location's lexical scope. In this case, splitting of an interval
791 // can result in an interval outside of the scope being created,
792 // causing extra unnecessary DBG_VALUEs to be emitted. To prevent
793 // this, trim the intervals to the lexical scope.
794
795 LexicalScope *Scope = LS.findLexicalScope(dl);
796 if (!Scope)
797 return;
798
799 SlotIndex PrevEnd;
800 LocMap::iterator I = locInts.begin();
801
802 // Iterate over the lexical scope ranges. Each time round the loop
803 // we check the intervals for overlap with the end of the previous
804 // range and the start of the next. The first range is handled as
805 // a special case where there is no PrevEnd.
806 for (const InsnRange &Range : Scope->getRanges()) {
807 SlotIndex RStart = LIS.getInstructionIndex(*Range.first);
808 SlotIndex REnd = LIS.getInstructionIndex(*Range.second);
809
810 // At the start of each iteration I has been advanced so that
811 // I.stop() >= PrevEnd. Check for overlap.
812 if (PrevEnd && I.start() < PrevEnd) {
813 SlotIndex IStop = I.stop();
814 DbgValueLocation Loc = I.value();
815
816 // Stop overlaps previous end - trim the end of the interval to
817 // the scope range.
818 I.setStopUnchecked(PrevEnd);
819 ++I;
820
821 // If the interval also overlaps the start of the "next" (i.e.
822 // current) range create a new interval for the remainder (which
823 // may be further trimmed).
824 if (RStart < IStop)
825 I.insert(RStart, IStop, Loc);
826 }
827
828 // Advance I so that I.stop() >= RStart, and check for overlap.
829 I.advanceTo(RStart);
830 if (!I.valid())
831 return;
832
833 if (I.start() < RStart) {
834 // Interval start overlaps range - trim to the scope range.
835 I.setStartUnchecked(RStart);
836 // Remember that this interval was trimmed.
837 trimmedDefs.insert(RStart);
838 }
839
840 // The end of a lexical scope range is the last instruction in the
841 // range. To convert to an interval we need the index of the
842 // instruction after it.
843 REnd = REnd.getNextIndex();
844
845 // Advance I to first interval outside current range.
846 I.advanceTo(REnd);
847 if (!I.valid())
848 return;
849
850 PrevEnd = REnd;
851 }
852
853 // Check for overlap with end of final range.
854 if (PrevEnd && I.start() < PrevEnd)
855 I.setStopUnchecked(PrevEnd);
856}
857
858void LDVImpl::computeIntervals() {
859 LexicalScopes LS;
860 LS.initialize(*MF);
861
862 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
863 userValues[i]->computeIntervals(MF->getRegInfo(), *TRI, *LIS, LS);
864 userValues[i]->mapVirtRegs(this);
865 }
866}
867
868bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
869 clear();
870 MF = &mf;
871 LIS = &pass.getAnalysis<LiveIntervals>();
872 TRI = mf.getSubtarget().getRegisterInfo();
873 LLVM_DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
<< mf.getName() << " **********\n"; } } while (false
)
874 << mf.getName() << " **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
<< mf.getName() << " **********\n"; } } while (false
)
;
875
876 bool Changed = collectDebugValues(mf);
877 computeIntervals();
878 LLVM_DEBUG(print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { print(dbgs()); } } while (false)
;
879 ModifiedMF = Changed;
880 return Changed;
881}
882
883static void removeDebugValues(MachineFunction &mf) {
884 for (MachineBasicBlock &MBB : mf) {
885 for (auto MBBI = MBB.begin(), MBBE = MBB.end(); MBBI != MBBE; ) {
886 if (!MBBI->isDebugValue()) {
887 ++MBBI;
888 continue;
889 }
890 MBBI = MBB.erase(MBBI);
891 }
892 }
893}
894
895bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
896 if (!EnableLDV)
897 return false;
898 if (!mf.getFunction().getSubprogram()) {
899 removeDebugValues(mf);
900 return false;
901 }
902 if (!pImpl)
903 pImpl = new LDVImpl(this);
904 return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);
905}
906
907void LiveDebugVariables::releaseMemory() {
908 if (pImpl)
909 static_cast<LDVImpl*>(pImpl)->clear();
910}
911
912LiveDebugVariables::~LiveDebugVariables() {
913 if (pImpl)
914 delete static_cast<LDVImpl*>(pImpl);
915}
916
917//===----------------------------------------------------------------------===//
918// Live Range Splitting
919//===----------------------------------------------------------------------===//
920
921bool
922UserValue::splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
923 LiveIntervals& LIS) {
924 LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
925 dbgs() << "Splitting Loc" << OldLocNo << '\t';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
926 print(dbgs(), nullptr);do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
927 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
;
928 bool DidChange = false;
929 LocMap::iterator LocMapI;
930 LocMapI.setMap(locInts);
931 for (unsigned i = 0; i != NewRegs.size(); ++i) {
932 LiveInterval *LI = &LIS.getInterval(NewRegs[i]);
933 if (LI->empty())
934 continue;
935
936 // Don't allocate the new LocNo until it is needed.
937 unsigned NewLocNo = UndefLocNo;
938
939 // Iterate over the overlaps between locInts and LI.
940 LocMapI.find(LI->beginIndex());
941 if (!LocMapI.valid())
942 continue;
943 LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
944 LiveInterval::iterator LIE = LI->end();
945 while (LocMapI.valid() && LII != LIE) {
946 // At this point, we know that LocMapI.stop() > LII->start.
947 LII = LI->advanceTo(LII, LocMapI.start());
948 if (LII == LIE)
949 break;
950
951 // Now LII->end > LocMapI.start(). Do we have an overlap?
952 if (LocMapI.value().locNo() == OldLocNo && LII->start < LocMapI.stop()) {
953 // Overlapping correct location. Allocate NewLocNo now.
954 if (NewLocNo == UndefLocNo) {
955 MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
956 MO.setSubReg(locations[OldLocNo].getSubReg());
957 NewLocNo = getLocationNo(MO);
958 DidChange = true;
959 }
960
961 SlotIndex LStart = LocMapI.start();
962 SlotIndex LStop = LocMapI.stop();
963 DbgValueLocation OldLoc = LocMapI.value();
964
965 // Trim LocMapI down to the LII overlap.
966 if (LStart < LII->start)
967 LocMapI.setStartUnchecked(LII->start);
968 if (LStop > LII->end)
969 LocMapI.setStopUnchecked(LII->end);
970
971 // Change the value in the overlap. This may trigger coalescing.
972 LocMapI.setValue(OldLoc.changeLocNo(NewLocNo));
973
974 // Re-insert any removed OldLocNo ranges.
975 if (LStart < LocMapI.start()) {
976 LocMapI.insert(LStart, LocMapI.start(), OldLoc);
977 ++LocMapI;
978 assert(LocMapI.valid() && "Unexpected coalescing")((LocMapI.valid() && "Unexpected coalescing") ? static_cast
<void> (0) : __assert_fail ("LocMapI.valid() && \"Unexpected coalescing\""
, "/build/llvm-toolchain-snapshot-8~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 978, __PRETTY_FUNCTION__))
;
979 }
980 if (LStop > LocMapI.stop()) {
981 ++LocMapI;
982 LocMapI.insert(LII->end, LStop, OldLoc);
983 --LocMapI;
984 }
985 }
986
987 // Advance to the next overlap.
988 if (LII->end < LocMapI.stop()) {
989 if (++LII == LIE)
990 break;
991 LocMapI.advanceTo(LII->start);
992 } else {
993 ++LocMapI;
994 if (!LocMapI.valid())
995 break;
996 LII = LI->advanceTo(LII, LocMapI.start());
997 }
998 }
999 }
1000
1001 // Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
1002 locations.erase(locations.begin() + OldLocNo);
1003 LocMapI.goToBegin();
1004 while (LocMapI.valid()) {
1005 DbgValueLocation v = LocMapI.value();
1006 if (v.locNo() == OldLocNo) {
1007 LLVM_DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Erasing [" << LocMapI
.start() << ';' << LocMapI.stop() << ")\n";
} } while (false)
1008 << LocMapI.stop() << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Erasing [" << LocMapI
.start() << ';' << LocMapI.stop() << ")\n";
} } while (false)
;
1009 LocMapI.erase();
1010 } else {
1011 // Undef values always have location number UndefLocNo, so don't change
1012 // locNo in that case. See getLocationNo().
1013 if (!v.isUndef() && v.locNo() > OldLocNo)
1014 LocMapI.setValueUnchecked(v.changeLocNo(v.locNo() - 1));
1015 ++LocMapI;
1016 }
1017 }
1018
1019 LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1020 dbgs() << "Split result: \t";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1021 print(dbgs(), nullptr);do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1022 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
;
1023 return DidChange;
1024}
1025
1026bool
1027UserValue::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
1028 LiveIntervals &LIS) {
1029 bool DidChange = false;
1030 // Split locations referring to OldReg. Iterate backwards so splitLocation can
1031 // safely erase unused locations.
1032 for (unsigned i = locations.size(); i ; --i) {
1033 unsigned LocNo = i-1;
1034 const MachineOperand *Loc = &locations[LocNo];
1035 if (!Loc->isReg() || Loc->getReg() != OldReg)
1036 continue;
1037 DidChange |= splitLocation(LocNo, NewRegs, LIS);
1038 }
1039 return DidChange;
1040}
1041
1042void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs) {
1043 bool DidChange = false;
1044 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
1045 DidChange |= UV->splitRegister(OldReg, NewRegs, *LIS);
1046
1047 if (!DidChange)
1048 return;
1049
1050 // Map all of the new virtual registers.
1051 UserValue *UV = lookupVirtReg(OldReg);
1052 for (unsigned i = 0; i != NewRegs.size(); ++i)
1053 mapVirtReg(NewRegs[i], UV);
1054}
1055
1056void LiveDebugVariables::
1057splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, LiveIntervals &LIS) {
1058 if (pImpl)
1059 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
1060}
1061
1062void UserValue::rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF,
1063 const TargetInstrInfo &TII,
1064 const TargetRegisterInfo &TRI,
1065 SpillOffsetMap &SpillOffsets) {
1066 // Build a set of new locations with new numbers so we can coalesce our
1067 // IntervalMap if two vreg intervals collapse to the same physical location.
1068 // Use MapVector instead of SetVector because MapVector::insert returns the
1069 // position of the previously or newly inserted element. The boolean value
1070 // tracks if the location was produced by a spill.
1071 // FIXME: This will be problematic if we ever support direct and indirect
1072 // frame index locations, i.e. expressing both variables in memory and
1073 // 'int x, *px = &x'. The "spilled" bit must become part of the location.
1074 MapVector<MachineOperand, std::pair<bool, unsigned>> NewLocations;
1075 SmallVector<unsigned, 4> LocNoMap(locations.size());
1076 for (unsigned I = 0, E = locations.size(); I != E; ++I) {
1077 bool Spilled = false;
1078 unsigned SpillOffset = 0;
1079 MachineOperand Loc = locations[I];
1080 // Only virtual registers are rewritten.
1081 if (Loc.isReg() && Loc.getReg() &&
1082 TargetRegisterInfo::isVirtualRegister(Loc.getReg())) {
1083 unsigned VirtReg = Loc.getReg();
1084 if (VRM.isAssignedReg(VirtReg) &&
1085 TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
1086 // This can create a %noreg operand in rare cases when the sub-register
1087 // index is no longer available. That means the user value is in a
1088 // non-existent sub-register, and %noreg is exactly what we want.
1089 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
1090 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
1091 // Retrieve the stack slot offset.
1092 unsigned SpillSize;
1093 const MachineRegisterInfo &MRI = MF.getRegInfo();
1094 const TargetRegisterClass *TRC = MRI.getRegClass(VirtReg);
1095 bool Success = TII.getStackSlotRange(TRC, Loc.getSubReg(), SpillSize,
1096 SpillOffset, MF);
1097
1098 // FIXME: Invalidate the location if the offset couldn't be calculated.
1099 (void)Success;
1100
1101 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
1102 Spilled = true;
1103 } else {
1104 Loc.setReg(0);
1105 Loc.setSubReg(0);
1106 }
1107 }
1108
1109 // Insert this location if it doesn't already exist and record a mapping
1110 // from the old number to the new number.
1111 auto InsertResult = NewLocations.insert({Loc, {Spilled, SpillOffset}});
1112 unsigned NewLocNo = std::distance(NewLocations.begin(), InsertResult.first);
1113 LocNoMap[I] = NewLocNo;
1114 }
1115
1116 // Rewrite the locations and record the stack slot offsets for spills.
1117 locations.clear();
1118 SpillOffsets.clear();
1119 for (auto &Pair : NewLocations) {
1120 bool Spilled;
1121 unsigned SpillOffset;
1122 std::tie(Spilled, SpillOffset) = Pair.second;
1123 locations.push_back(Pair.first);
1124 if (Spilled) {
1125 unsigned NewLocNo = std::distance(&*NewLocations.begin(), &Pair);
1126 SpillOffsets[NewLocNo] = SpillOffset;
1127 }
1128 }
1129
1130 // Update the interval map, but only coalesce left, since intervals to the
1131 // right use the old location numbers. This should merge two contiguous
1132 // DBG_VALUE intervals with different vregs that were allocated to the same
1133 // physical register.
1134 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
1135 DbgValueLocation Loc = I.value();
1136 // Undef values don't exist in locations (and thus not in LocNoMap either)
1137 // so skip over them. See getLocationNo().
1138 if (Loc.isUndef())
1139 continue;
1140 unsigned NewLocNo = LocNoMap[Loc.locNo()];
1141 I.setValueUnchecked(Loc.changeLocNo(NewLocNo));
1142 I.setStart(I.start());
1143 }
1144}
1145
1146/// Find an iterator for inserting a DBG_VALUE instruction.
1147static MachineBasicBlock::iterator
1148findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
1149 LiveIntervals &LIS) {
1150 SlotIndex Start = LIS.getMBBStartIdx(MBB);
1151 Idx = Idx.getBaseIndex();
1152
1153 // Try to find an insert location by going backwards from Idx.
1154 MachineInstr *MI;
1155 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
1156 // We've reached the beginning of MBB.
1157 if (Idx == Start) {
1158 MachineBasicBlock::iterator I = MBB->SkipPHIsLabelsAndDebug(MBB->begin());
1159 return I;
1160 }
1161 Idx = Idx.getPrevIndex();
1162 }
1163
1164 // Don't insert anything after the first terminator, though.
1165 return MI->isTerminator() ? MBB->getFirstTerminator() :
1166 std::next(MachineBasicBlock::iterator(MI));
1167}
1168
1169/// Find an iterator for inserting the next DBG_VALUE instruction
1170/// (or end if no more insert locations found).
1171static MachineBasicBlock::iterator
1172findNextInsertLocation(MachineBasicBlock *MBB,
1173 MachineBasicBlock::iterator I,
1174 SlotIndex StopIdx, MachineOperand &LocMO,
1175 LiveIntervals &LIS,
1176 const TargetRegisterInfo &TRI) {
1177 if (!LocMO.isReg())
1178 return MBB->instr_end();
1179 unsigned Reg = LocMO.getReg();
1180
1181 // Find the next instruction in the MBB that define the register Reg.
1182 while (I != MBB->end() && !I->isTerminator()) {
1183 if (!LIS.isNotInMIMap(*I) &&
1184 SlotIndex::isEarlierEqualInstr(StopIdx, LIS.getInstructionIndex(*I)))
1185 break;
1186 if (I->definesRegister(Reg, &TRI))
1187 // The insert location is directly after the instruction/bundle.
1188 return std::next(I);
1189 ++I;
1190 }
1191 return MBB->end();
1192}
1193
1194void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
1195 SlotIndex StopIdx, DbgValueLocation Loc,
1196 bool Spilled, unsigned SpillOffset,
1197 LiveIntervals &LIS, const TargetInstrInfo &TII,
1198 const TargetRegisterInfo &TRI) {
1199 SlotIndex MBBEndIdx = LIS.getMBBEndIdx(&*MBB);
1200 // Only search within the current MBB.
1201 StopIdx = (MBBEndIdx < StopIdx) ? MBBEndIdx : StopIdx;
1202 MachineBasicBlock::iterator I = findInsertLocation(MBB, StartIdx, LIS);
1203 // Undef values don't exist in locations so create new "noreg" register MOs
1204 // for them. See getLocationNo().
1205 MachineOperand MO = !Loc.isUndef() ?
1206 locations[Loc.locNo()] :
1207 MachineOperand::CreateReg(/* Reg */ 0, /* isDef */ false, /* isImp */ false,
1208 /* isKill */ false, /* isDead */ false,
1209 /* isUndef */ false, /* isEarlyClobber */ false,
1210 /* SubReg */ 0, /* isDebug */ true);
1211
1212 ++NumInsertedDebugValues;
1213
1214 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~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 1216, __PRETTY_FUNCTION__))
1215 ->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~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 1216, __PRETTY_FUNCTION__))
1216 "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~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 1216, __PRETTY_FUNCTION__))
;
1217
1218 // If the location was spilled, the new DBG_VALUE will be indirect. If the
1219 // original DBG_VALUE was indirect, we need to add DW_OP_deref to indicate
1220 // that the original virtual register was a pointer. Also, add the stack slot
1221 // offset for the spilled register to the expression.
1222 const DIExpression *Expr = Expression;
1223 bool IsIndirect = Loc.wasIndirect();
1224 if (Spilled) {
1225 auto Deref = IsIndirect ? DIExpression::WithDeref : DIExpression::NoDeref;
1226 Expr =
1227 DIExpression::prepend(Expr, DIExpression::NoDeref, SpillOffset, Deref);
1228 IsIndirect = true;
1229 }
1230
1231 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~svn345461/lib/CodeGen/LiveDebugVariables.cpp"
, 1231, __PRETTY_FUNCTION__))
;
1232
1233 do {
1234 BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
1235 IsIndirect, MO, Variable, Expr);
1236
1237 // Continue and insert DBG_VALUES after every redefinition of register
1238 // associated with the debug value within the range
1239 I = findNextInsertLocation(MBB, I, StopIdx, MO, LIS, TRI);
1240 } while (I != MBB->end());
1241}
1242
1243void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
1244 const TargetInstrInfo &TII,
1245 const TargetRegisterInfo &TRI,
1246 const SpillOffsetMap &SpillOffsets) {
1247 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
1248
1249 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
1250 SlotIndex Start = I.start();
1251 SlotIndex Stop = I.stop();
1252 DbgValueLocation Loc = I.value();
1253 auto SpillIt =
1254 !Loc.isUndef() ? SpillOffsets.find(Loc.locNo()) : SpillOffsets.end();
1255 bool Spilled = SpillIt != SpillOffsets.end();
1256 unsigned SpillOffset = Spilled ? SpillIt->second : 0;
1257
1258 // If the interval start was trimmed to the lexical scope insert the
1259 // DBG_VALUE at the previous index (otherwise it appears after the
1260 // first instruction in the range).
1261 if (trimmedDefs.count(Start))
1262 Start = Start.getPrevIndex();
1263
1264 LLVM_DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << Loc.locNo())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "\t[" << Start <<
';' << Stop << "):" << Loc.locNo(); } } while
(false)
;
1265 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start)->getIterator();
1266 SlotIndex MBBEnd = LIS.getMBBEndIdx(&*MBB);
1267
1268 LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB) << '-' << MBBEnd; } } while (false)
;
1269 insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, SpillOffset, LIS, TII,
1270 TRI);
1271 // This interval may span multiple basic blocks.
1272 // Insert a DBG_VALUE into each one.
1273 while (Stop > MBBEnd) {
1274 // Move to the next block.
1275 Start = MBBEnd;
1276 if (++MBB == MFEnd)
1277 break;
1278 MBBEnd = LIS.getMBBEndIdx(&*MBB);
1279 LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB) << '-' << MBBEnd; } } while (false)
;
1280 insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, SpillOffset, LIS, TII,
1281 TRI);
1282 }
1283 LLVM_DEBUG(dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << '\n'; } } while (false)
;
1284 if (MBB == MFEnd)
1285 break;
1286
1287 ++I;
1288 }
1289}
1290
1291void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
1292 LLVM_DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n"
; } } while (false)
;
1293 if (!MF)
1294 return;
1295 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
1296 SpillOffsetMap SpillOffsets;
1297 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
1298 LLVM_DEBUG(userValues[i]->print(dbgs(), TRI))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { userValues[i]->print(dbgs(), TRI); } }
while (false)
;
1299 userValues[i]->rewriteLocations(*VRM, *MF, *TII, *TRI, SpillOffsets);
1300 userValues[i]->emitDebugValues(VRM, *LIS, *TII, *TRI, SpillOffsets);
1301 }
1302 EmitDone = true;
1303}
1304
1305void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
1306 if (pImpl)
1307 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
1308}
1309
1310bool LiveDebugVariables::doInitialization(Module &M) {
1311 return Pass::doInitialization(M);
1312}
1313
1314#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1315LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void LiveDebugVariables::dump() const {
1316 if (pImpl)
1317 static_cast<LDVImpl*>(pImpl)->print(dbgs());
1318}
1319#endif