Bug Summary

File:lib/CodeGen/LiveDebugVariables.cpp
Warning:line 641, 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~svn338205/build-llvm/lib/CodeGen -I /build/llvm-toolchain-snapshot-7~svn338205/lib/CodeGen -I /build/llvm-toolchain-snapshot-7~svn338205/build-llvm/include -I /build/llvm-toolchain-snapshot-7~svn338205/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/x86_64-linux-gnu/c++/8 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/x86_64-linux-gnu/c++/8 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/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/lib/gcc/x86_64-linux-gnu/8/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-class-memaccess -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-7~svn338205/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-2018-07-29-043837-17923-1 -x c++ /build/llvm-toolchain-snapshot-7~svn338205/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")(static_cast <bool> (locNo() == LocNo && "location truncation"
) ? void (0) : __assert_fail ("locNo() == LocNo && \"location truncation\""
, "/build/llvm-toolchain-snapshot-7~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 104, __extension__ __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
138namespace {
139
140class LDVImpl;
141
142/// UserValue - A user value is a part of a debug info user variable.
143///
144/// A DBG_VALUE instruction notes that (a sub-register of) a virtual register
145/// holds part of a user variable. The part is identified by a byte offset.
146///
147/// UserValues are grouped into equivalence classes for easier searching. Two
148/// user values are related if they refer to the same variable, or if they are
149/// held by the same virtual register. The equivalence class is the transitive
150/// closure of that relation.
151class UserValue {
152 const DILocalVariable *Variable; ///< The debug info variable we are part of.
153 const DIExpression *Expression; ///< Any complex address expression.
154 DebugLoc dl; ///< The debug location for the variable. This is
155 ///< used by dwarf writer to find lexical scope.
156 UserValue *leader; ///< Equivalence class leader.
157 UserValue *next = nullptr; ///< Next value in equivalence class, or null.
158
159 /// Numbered locations referenced by locmap.
160 SmallVector<MachineOperand, 4> locations;
161
162 /// Map of slot indices where this value is live.
163 LocMap locInts;
164
165 /// Set of interval start indexes that have been trimmed to the
166 /// lexical scope.
167 SmallSet<SlotIndex, 2> trimmedDefs;
168
169 /// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo.
170 void insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
171 SlotIndex StopIdx,
172 DbgValueLocation Loc, bool Spilled, LiveIntervals &LIS,
173 const TargetInstrInfo &TII,
174 const TargetRegisterInfo &TRI);
175
176 /// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs
177 /// is live. Returns true if any changes were made.
178 bool splitLocation(unsigned OldLocNo, ArrayRef<unsigned> NewRegs,
179 LiveIntervals &LIS);
180
181public:
182 /// UserValue - Create a new UserValue.
183 UserValue(const DILocalVariable *var, const DIExpression *expr, DebugLoc L,
184 LocMap::Allocator &alloc)
185 : Variable(var), Expression(expr), dl(std::move(L)), leader(this),
186 locInts(alloc) {}
187
188 /// getLeader - Get the leader of this value's equivalence class.
189 UserValue *getLeader() {
190 UserValue *l = leader;
191 while (l != l->leader)
192 l = l->leader;
193 return leader = l;
194 }
195
196 /// getNext - Return the next UserValue in the equivalence class.
197 UserValue *getNext() const { return next; }
198
199 /// match - Does this UserValue match the parameters?
200 bool match(const DILocalVariable *Var, const DIExpression *Expr,
201 const DILocation *IA) const {
202 // FIXME: The fragment should be part of the equivalence class, but not
203 // other things in the expression like stack values.
204 return Var == Variable && Expr == Expression && dl->getInlinedAt() == IA;
205 }
206
207 /// merge - Merge equivalence classes.
208 static UserValue *merge(UserValue *L1, UserValue *L2) {
209 L2 = L2->getLeader();
210 if (!L1)
211 return L2;
212 L1 = L1->getLeader();
213 if (L1 == L2)
214 return L1;
215 // Splice L2 before L1's members.
216 UserValue *End = L2;
217 while (End->next) {
218 End->leader = L1;
219 End = End->next;
220 }
221 End->leader = L1;
222 End->next = L1->next;
223 L1->next = L2;
224 return L1;
225 }
226
227 /// Return the location number that matches Loc.
228 ///
229 /// For undef values we always return location number UndefLocNo without
230 /// inserting anything in locations. Since locations is a vector and the
231 /// location number is the position in the vector and UndefLocNo is ~0,
232 /// we would need a very big vector to put the value at the right position.
233 unsigned getLocationNo(const MachineOperand &LocMO) {
234 if (LocMO.isReg()) {
235 if (LocMO.getReg() == 0)
236 return UndefLocNo;
237 // For register locations we dont care about use/def and other flags.
238 for (unsigned i = 0, e = locations.size(); i != e; ++i)
239 if (locations[i].isReg() &&
240 locations[i].getReg() == LocMO.getReg() &&
241 locations[i].getSubReg() == LocMO.getSubReg())
242 return i;
243 } else
244 for (unsigned i = 0, e = locations.size(); i != e; ++i)
245 if (LocMO.isIdenticalTo(locations[i]))
246 return i;
247 locations.push_back(LocMO);
248 // We are storing a MachineOperand outside a MachineInstr.
249 locations.back().clearParent();
250 // Don't store def operands.
251 if (locations.back().isReg()) {
252 if (locations.back().isDef())
253 locations.back().setIsDead(false);
254 locations.back().setIsUse();
255 }
256 return locations.size() - 1;
257 }
258
259 /// mapVirtRegs - Ensure that all virtual register locations are mapped.
260 void mapVirtRegs(LDVImpl *LDV);
261
262 /// addDef - Add a definition point to this value.
263 void addDef(SlotIndex Idx, const MachineOperand &LocMO, bool IsIndirect) {
264 DbgValueLocation Loc(getLocationNo(LocMO), IsIndirect);
265 // Add a singular (Idx,Idx) -> Loc mapping.
266 LocMap::iterator I = locInts.find(Idx);
267 if (!I.valid() || I.start() != Idx)
268 I.insert(Idx, Idx.getNextSlot(), Loc);
269 else
270 // A later DBG_VALUE at the same SlotIndex overrides the old location.
271 I.setValue(Loc);
272 }
273
274 /// extendDef - Extend the current definition as far as possible down.
275 /// Stop when meeting an existing def or when leaving the live
276 /// range of VNI.
277 /// End points where VNI is no longer live are added to Kills.
278 /// @param Idx Starting point for the definition.
279 /// @param Loc Location number to propagate.
280 /// @param LR Restrict liveness to where LR has the value VNI. May be null.
281 /// @param VNI When LR is not null, this is the value to restrict to.
282 /// @param Kills Append end points of VNI's live range to Kills.
283 /// @param LIS Live intervals analysis.
284 void extendDef(SlotIndex Idx, DbgValueLocation Loc,
285 LiveRange *LR, const VNInfo *VNI,
286 SmallVectorImpl<SlotIndex> *Kills,
287 LiveIntervals &LIS);
288
289 /// addDefsFromCopies - The value in LI/LocNo may be copies to other
290 /// registers. Determine if any of the copies are available at the kill
291 /// points, and add defs if possible.
292 /// @param LI Scan for copies of the value in LI->reg.
293 /// @param LocNo Location number of LI->reg.
294 /// @param WasIndirect Indicates if the original use of LI->reg was indirect
295 /// @param Kills Points where the range of LocNo could be extended.
296 /// @param NewDefs Append (Idx, LocNo) of inserted defs here.
297 void addDefsFromCopies(
298 LiveInterval *LI, unsigned LocNo, bool WasIndirect,
299 const SmallVectorImpl<SlotIndex> &Kills,
300 SmallVectorImpl<std::pair<SlotIndex, DbgValueLocation>> &NewDefs,
301 MachineRegisterInfo &MRI, LiveIntervals &LIS);
302
303 /// computeIntervals - Compute the live intervals of all locations after
304 /// collecting all their def points.
305 void computeIntervals(MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
306 LiveIntervals &LIS, LexicalScopes &LS);
307
308 /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
309 /// live. Returns true if any changes were made.
310 bool splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
311 LiveIntervals &LIS);
312
313 /// rewriteLocations - Rewrite virtual register locations according to the
314 /// provided virtual register map. Record which locations were spilled.
315 void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI,
316 BitVector &SpilledLocations);
317
318 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
319 void emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
320 const TargetInstrInfo &TII,
321 const TargetRegisterInfo &TRI,
322 const BitVector &SpilledLocations);
323
324 /// getDebugLoc - Return DebugLoc of this UserValue.
325 DebugLoc getDebugLoc() { return dl;}
326
327 void print(raw_ostream &, const TargetRegisterInfo *);
328};
329
330/// LDVImpl - Implementation of the LiveDebugVariables pass.
331class LDVImpl {
332 LiveDebugVariables &pass;
333 LocMap::Allocator allocator;
334 MachineFunction *MF = nullptr;
335 LiveIntervals *LIS;
336 const TargetRegisterInfo *TRI;
337
338 /// Whether emitDebugValues is called.
339 bool EmitDone = false;
340
341 /// Whether the machine function is modified during the pass.
342 bool ModifiedMF = false;
343
344 /// userValues - All allocated UserValue instances.
345 SmallVector<std::unique_ptr<UserValue>, 8> userValues;
346
347 /// Map virtual register to eq class leader.
348 using VRMap = DenseMap<unsigned, UserValue *>;
349 VRMap virtRegToEqClass;
350
351 /// Map user variable to eq class leader.
352 using UVMap = DenseMap<const DILocalVariable *, UserValue *>;
353 UVMap userVarMap;
354
355 /// getUserValue - Find or create a UserValue.
356 UserValue *getUserValue(const DILocalVariable *Var, const DIExpression *Expr,
357 const DebugLoc &DL);
358
359 /// lookupVirtReg - Find the EC leader for VirtReg or null.
360 UserValue *lookupVirtReg(unsigned VirtReg);
361
362 /// handleDebugValue - Add DBG_VALUE instruction to our maps.
363 /// @param MI DBG_VALUE instruction
364 /// @param Idx Last valid SLotIndex before instruction.
365 /// @return True if the DBG_VALUE instruction should be deleted.
366 bool handleDebugValue(MachineInstr &MI, SlotIndex Idx);
367
368 /// collectDebugValues - Collect and erase all DBG_VALUE instructions, adding
369 /// a UserValue def for each instruction.
370 /// @param mf MachineFunction to be scanned.
371 /// @return True if any debug values were found.
372 bool collectDebugValues(MachineFunction &mf);
373
374 /// computeIntervals - Compute the live intervals of all user values after
375 /// collecting all their def points.
376 void computeIntervals();
377
378public:
379 LDVImpl(LiveDebugVariables *ps) : pass(*ps) {}
380
381 bool runOnMachineFunction(MachineFunction &mf);
382
383 /// clear - Release all memory.
384 void clear() {
385 MF = nullptr;
386 userValues.clear();
387 virtRegToEqClass.clear();
388 userVarMap.clear();
389 // Make sure we call emitDebugValues if the machine function was modified.
390 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~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 391, __extension__ __PRETTY_FUNCTION__))
391 "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~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 391, __extension__ __PRETTY_FUNCTION__))
;
392 EmitDone = false;
393 ModifiedMF = false;
394 }
395
396 /// mapVirtReg - Map virtual register to an equivalence class.
397 void mapVirtReg(unsigned VirtReg, UserValue *EC);
398
399 /// splitRegister - Replace all references to OldReg with NewRegs.
400 void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs);
401
402 /// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
403 void emitDebugValues(VirtRegMap *VRM);
404
405 void print(raw_ostream&);
406};
407
408} // end anonymous namespace
409
410#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
411static void printDebugLoc(const DebugLoc &DL, raw_ostream &CommentOS,
412 const LLVMContext &Ctx) {
413 if (!DL)
414 return;
415
416 auto *Scope = cast<DIScope>(DL.getScope());
417 // Omit the directory, because it's likely to be long and uninteresting.
418 CommentOS << Scope->getFilename();
419 CommentOS << ':' << DL.getLine();
420 if (DL.getCol() != 0)
421 CommentOS << ':' << DL.getCol();
422
423 DebugLoc InlinedAtDL = DL.getInlinedAt();
424 if (!InlinedAtDL)
425 return;
426
427 CommentOS << " @[ ";
428 printDebugLoc(InlinedAtDL, CommentOS, Ctx);
429 CommentOS << " ]";
430}
431
432static void printExtendedName(raw_ostream &OS, const DILocalVariable *V,
433 const DILocation *DL) {
434 const LLVMContext &Ctx = V->getContext();
435 StringRef Res = V->getName();
436 if (!Res.empty())
437 OS << Res << "," << V->getLine();
438 if (auto *InlinedAt = DL->getInlinedAt()) {
439 if (DebugLoc InlinedAtDL = InlinedAt) {
440 OS << " @[";
441 printDebugLoc(InlinedAtDL, OS, Ctx);
442 OS << "]";
443 }
444 }
445}
446
447void UserValue::print(raw_ostream &OS, const TargetRegisterInfo *TRI) {
448 auto *DV = cast<DILocalVariable>(Variable);
449 OS << "!\"";
450 printExtendedName(OS, DV, dl);
451
452 OS << "\"\t";
453 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
454 OS << " [" << I.start() << ';' << I.stop() << "):";
455 if (I.value().isUndef())
456 OS << "undef";
457 else {
458 OS << I.value().locNo();
459 if (I.value().wasIndirect())
460 OS << " ind";
461 }
462 }
463 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
464 OS << " Loc" << i << '=';
465 locations[i].print(OS, TRI);
466 }
467 OS << '\n';
468}
469
470void LDVImpl::print(raw_ostream &OS) {
471 OS << "********** DEBUG VARIABLES **********\n";
472 for (unsigned i = 0, e = userValues.size(); i != e; ++i)
473 userValues[i]->print(OS, TRI);
474}
475#endif
476
477void UserValue::mapVirtRegs(LDVImpl *LDV) {
478 for (unsigned i = 0, e = locations.size(); i != e; ++i)
479 if (locations[i].isReg() &&
480 TargetRegisterInfo::isVirtualRegister(locations[i].getReg()))
481 LDV->mapVirtReg(locations[i].getReg(), this);
482}
483
484UserValue *LDVImpl::getUserValue(const DILocalVariable *Var,
485 const DIExpression *Expr, const DebugLoc &DL) {
486 UserValue *&Leader = userVarMap[Var];
487 if (Leader) {
488 UserValue *UV = Leader->getLeader();
489 Leader = UV;
490 for (; UV; UV = UV->getNext())
491 if (UV->match(Var, Expr, DL->getInlinedAt()))
492 return UV;
493 }
494
495 userValues.push_back(
496 llvm::make_unique<UserValue>(Var, Expr, DL, allocator));
497 UserValue *UV = userValues.back().get();
498 Leader = UserValue::merge(Leader, UV);
499 return UV;
500}
501
502void LDVImpl::mapVirtReg(unsigned VirtReg, UserValue *EC) {
503 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~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 503, __extension__ __PRETTY_FUNCTION__))
;
504 UserValue *&Leader = virtRegToEqClass[VirtReg];
505 Leader = UserValue::merge(Leader, EC);
506}
507
508UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
509 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
510 return UV->getLeader();
511 return nullptr;
512}
513
514bool LDVImpl::handleDebugValue(MachineInstr &MI, SlotIndex Idx) {
515 // DBG_VALUE loc, offset, variable
516 if (MI.getNumOperands() != 4 ||
517 !(MI.getOperand(1).isReg() || MI.getOperand(1).isImm()) ||
518 !MI.getOperand(2).isMetadata()) {
519 LLVM_DEBUG(dbgs() << "Can't handle " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Can't handle " <<
MI; } } while (false)
;
520 return false;
521 }
522
523 // Detect invalid DBG_VALUE instructions, with a debug-use of a virtual
524 // register that hasn't been defined yet. If we do not remove those here, then
525 // the re-insertion of the DBG_VALUE instruction after register allocation
526 // will be incorrect.
527 // TODO: If earlier passes are corrected to generate sane debug information
528 // (and if the machine verifier is improved to catch this), then these checks
529 // could be removed or replaced by asserts.
530 bool Discard = false;
531 if (MI.getOperand(0).isReg() &&
532 TargetRegisterInfo::isVirtualRegister(MI.getOperand(0).getReg())) {
533 const unsigned Reg = MI.getOperand(0).getReg();
534 if (!LIS->hasInterval(Reg)) {
535 // The DBG_VALUE is described by a virtual register that does not have a
536 // live interval. Discard the DBG_VALUE.
537 Discard = true;
538 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)
539 << " " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (no LIS interval): "
<< Idx << " " << MI; } } while (false)
;
540 } else {
541 // The DBG_VALUE is only valid if either Reg is live out from Idx, or Reg
542 // is defined dead at Idx (where Idx is the slot index for the instruction
543 // preceeding the DBG_VALUE).
544 const LiveInterval &LI = LIS->getInterval(Reg);
545 LiveQueryResult LRQ = LI.Query(Idx);
546 if (!LRQ.valueOutOrDead()) {
547 // We have found a DBG_VALUE with the value in a virtual register that
548 // is not live. Discard the DBG_VALUE.
549 Discard = true;
550 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)
551 << " " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (reg not live): "
<< Idx << " " << MI; } } while (false)
;
552 }
553 }
554 }
555
556 // Get or create the UserValue for (variable,offset) here.
557 bool IsIndirect = MI.getOperand(1).isImm();
558 if (IsIndirect)
559 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~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 559, __extension__ __PRETTY_FUNCTION__))
;
560 const DILocalVariable *Var = MI.getDebugVariable();
561 const DIExpression *Expr = MI.getDebugExpression();
562 UserValue *UV =
563 getUserValue(Var, Expr, MI.getDebugLoc());
564 if (!Discard)
565 UV->addDef(Idx, MI.getOperand(0), IsIndirect);
566 else {
567 MachineOperand MO = MachineOperand::CreateReg(0U, false);
568 MO.setIsDebug();
569 UV->addDef(Idx, MO, false);
570 }
571 return true;
572}
573
574bool LDVImpl::collectDebugValues(MachineFunction &mf) {
575 bool Changed = false;
576 for (MachineFunction::iterator MFI = mf.begin(), MFE = mf.end(); MFI != MFE;
577 ++MFI) {
578 MachineBasicBlock *MBB = &*MFI;
579 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
580 MBBI != MBBE;) {
581 if (!MBBI->isDebugValue()) {
582 ++MBBI;
583 continue;
584 }
585 // DBG_VALUE has no slot index, use the previous instruction instead.
586 SlotIndex Idx =
587 MBBI == MBB->begin()
588 ? LIS->getMBBStartIdx(MBB)
589 : LIS->getInstructionIndex(*std::prev(MBBI)).getRegSlot();
590 // Handle consecutive DBG_VALUE instructions with the same slot index.
591 do {
592 if (handleDebugValue(*MBBI, Idx)) {
593 MBBI = MBB->erase(MBBI);
594 Changed = true;
595 } else
596 ++MBBI;
597 } while (MBBI != MBBE && MBBI->isDebugValue());
598 }
599 }
600 return Changed;
601}
602
603/// We only propagate DBG_VALUES locally here. LiveDebugValues performs a
604/// data-flow analysis to propagate them beyond basic block boundaries.
605void UserValue::extendDef(SlotIndex Idx, DbgValueLocation Loc, LiveRange *LR,
606 const VNInfo *VNI, SmallVectorImpl<SlotIndex> *Kills,
607 LiveIntervals &LIS) {
608 SlotIndex Start = Idx;
609 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
610 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
611 LocMap::iterator I = locInts.find(Start);
612
613 // Limit to VNI's live range.
614 bool ToEnd = true;
615 if (LR && VNI) {
616 LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
617 if (!Segment || Segment->valno != VNI) {
618 if (Kills)
619 Kills->push_back(Start);
620 return;
621 }
622 if (Segment->end < Stop) {
623 Stop = Segment->end;
624 ToEnd = false;
625 }
626 }
627
628 // There could already be a short def at Start.
629 if (I.valid() && I.start() <= Start) {
630 // Stop when meeting a different location or an already extended interval.
631 Start = Start.getNextSlot();
632 if (I.value() != Loc || I.stop() != Start)
633 return;
634 // This is a one-slot placeholder. Just skip it.
635 ++I;
636 }
637
638 // Limited by the next def.
639 if (I.valid() && I.start() < Stop) {
640 Stop = I.start();
641 ToEnd = false;
Value stored to 'ToEnd' is never read
642 }
643 // Limited by VNI's live range.
644 else if (!ToEnd && Kills)
645 Kills->push_back(Stop);
646
647 if (Start < Stop)
648 I.insert(Start, Stop, Loc);
649}
650
651void UserValue::addDefsFromCopies(
652 LiveInterval *LI, unsigned LocNo, bool WasIndirect,
653 const SmallVectorImpl<SlotIndex> &Kills,
654 SmallVectorImpl<std::pair<SlotIndex, DbgValueLocation>> &NewDefs,
655 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
656 if (Kills.empty())
657 return;
658 // Don't track copies from physregs, there are too many uses.
659 if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
660 return;
661
662 // Collect all the (vreg, valno) pairs that are copies of LI.
663 SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
664 for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg)) {
665 MachineInstr *MI = MO.getParent();
666 // Copies of the full value.
667 if (MO.getSubReg() || !MI->isCopy())
668 continue;
669 unsigned DstReg = MI->getOperand(0).getReg();
670
671 // Don't follow copies to physregs. These are usually setting up call
672 // arguments, and the argument registers are always call clobbered. We are
673 // better off in the source register which could be a callee-saved register,
674 // or it could be spilled.
675 if (!TargetRegisterInfo::isVirtualRegister(DstReg))
676 continue;
677
678 // Is LocNo extended to reach this copy? If not, another def may be blocking
679 // it, or we are looking at a wrong value of LI.
680 SlotIndex Idx = LIS.getInstructionIndex(*MI);
681 LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
682 if (!I.valid() || I.value().locNo() != LocNo)
683 continue;
684
685 if (!LIS.hasInterval(DstReg))
686 continue;
687 LiveInterval *DstLI = &LIS.getInterval(DstReg);
688 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
689 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~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 689, __extension__ __PRETTY_FUNCTION__))
;
690 CopyValues.push_back(std::make_pair(DstLI, DstVNI));
691 }
692
693 if (CopyValues.empty())
694 return;
695
696 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)
697 << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Got " << CopyValues
.size() << " copies of " << *LI << '\n'; } }
while (false)
;
698
699 // Try to add defs of the copied values for each kill point.
700 for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
701 SlotIndex Idx = Kills[i];
702 for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
703 LiveInterval *DstLI = CopyValues[j].first;
704 const VNInfo *DstVNI = CopyValues[j].second;
705 if (DstLI->getVNInfoAt(Idx) != DstVNI)
706 continue;
707 // Check that there isn't already a def at Idx
708 LocMap::iterator I = locInts.find(Idx);
709 if (I.valid() && I.start() <= Idx)
710 continue;
711 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)
712 << 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)
;
713 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
714 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~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 714, __extension__ __PRETTY_FUNCTION__))
;
715 unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
716 DbgValueLocation NewLoc(LocNo, WasIndirect);
717 I.insert(Idx, Idx.getNextSlot(), NewLoc);
718 NewDefs.push_back(std::make_pair(Idx, NewLoc));
719 break;
720 }
721 }
722}
723
724void UserValue::computeIntervals(MachineRegisterInfo &MRI,
725 const TargetRegisterInfo &TRI,
726 LiveIntervals &LIS, LexicalScopes &LS) {
727 SmallVector<std::pair<SlotIndex, DbgValueLocation>, 16> Defs;
728
729 // Collect all defs to be extended (Skipping undefs).
730 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
731 if (!I.value().isUndef())
732 Defs.push_back(std::make_pair(I.start(), I.value()));
733
734 // Extend all defs, and possibly add new ones along the way.
735 for (unsigned i = 0; i != Defs.size(); ++i) {
736 SlotIndex Idx = Defs[i].first;
737 DbgValueLocation Loc = Defs[i].second;
738 const MachineOperand &LocMO = locations[Loc.locNo()];
739
740 if (!LocMO.isReg()) {
741 extendDef(Idx, Loc, nullptr, nullptr, nullptr, LIS);
742 continue;
743 }
744
745 // Register locations are constrained to where the register value is live.
746 if (TargetRegisterInfo::isVirtualRegister(LocMO.getReg())) {
747 LiveInterval *LI = nullptr;
748 const VNInfo *VNI = nullptr;
749 if (LIS.hasInterval(LocMO.getReg())) {
750 LI = &LIS.getInterval(LocMO.getReg());
751 VNI = LI->getVNInfoAt(Idx);
752 }
753 SmallVector<SlotIndex, 16> Kills;
754 extendDef(Idx, Loc, LI, VNI, &Kills, LIS);
755 if (LI)
756 addDefsFromCopies(LI, Loc.locNo(), Loc.wasIndirect(), Kills, Defs, MRI,
757 LIS);
758 continue;
759 }
760
761 // For physregs, we only mark the start slot idx. DwarfDebug will see it
762 // as if the DBG_VALUE is valid up until the end of the basic block, or
763 // the next def of the physical register. So we do not need to extend the
764 // range. It might actually happen that the DBG_VALUE is the last use of
765 // the physical register (e.g. if this is an unused input argument to a
766 // function).
767 }
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 LLVM_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 LLVM_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 LLVM_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~svn338205/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 LLVM_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 // Undef values always have location number UndefLocNo, so don't change
992 // locNo in that case. See getLocationNo().
993 if (!v.isUndef() && v.locNo() > OldLocNo)
994 LocMapI.setValueUnchecked(v.changeLocNo(v.locNo() - 1));
995 ++LocMapI;
996 }
997 }
998
999 LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1000 dbgs() << "Split result: \t";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1001 print(dbgs(), nullptr);do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1002 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
;
1003 return DidChange;
1004}
1005
1006bool
1007UserValue::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
1008 LiveIntervals &LIS) {
1009 bool DidChange = false;
1010 // Split locations referring to OldReg. Iterate backwards so splitLocation can
1011 // safely erase unused locations.
1012 for (unsigned i = locations.size(); i ; --i) {
1013 unsigned LocNo = i-1;
1014 const MachineOperand *Loc = &locations[LocNo];
1015 if (!Loc->isReg() || Loc->getReg() != OldReg)
1016 continue;
1017 DidChange |= splitLocation(LocNo, NewRegs, LIS);
1018 }
1019 return DidChange;
1020}
1021
1022void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs) {
1023 bool DidChange = false;
1024 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
1025 DidChange |= UV->splitRegister(OldReg, NewRegs, *LIS);
1026
1027 if (!DidChange)
1028 return;
1029
1030 // Map all of the new virtual registers.
1031 UserValue *UV = lookupVirtReg(OldReg);
1032 for (unsigned i = 0; i != NewRegs.size(); ++i)
1033 mapVirtReg(NewRegs[i], UV);
1034}
1035
1036void LiveDebugVariables::
1037splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, LiveIntervals &LIS) {
1038 if (pImpl)
1039 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
1040}
1041
1042void UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI,
1043 BitVector &SpilledLocations) {
1044 // Build a set of new locations with new numbers so we can coalesce our
1045 // IntervalMap if two vreg intervals collapse to the same physical location.
1046 // Use MapVector instead of SetVector because MapVector::insert returns the
1047 // position of the previously or newly inserted element. The boolean value
1048 // tracks if the location was produced by a spill.
1049 // FIXME: This will be problematic if we ever support direct and indirect
1050 // frame index locations, i.e. expressing both variables in memory and
1051 // 'int x, *px = &x'. The "spilled" bit must become part of the location.
1052 MapVector<MachineOperand, bool> NewLocations;
1053 SmallVector<unsigned, 4> LocNoMap(locations.size());
1054 for (unsigned I = 0, E = locations.size(); I != E; ++I) {
1055 bool Spilled = false;
1056 MachineOperand Loc = locations[I];
1057 // Only virtual registers are rewritten.
1058 if (Loc.isReg() && Loc.getReg() &&
1059 TargetRegisterInfo::isVirtualRegister(Loc.getReg())) {
1060 unsigned VirtReg = Loc.getReg();
1061 if (VRM.isAssignedReg(VirtReg) &&
1062 TargetRegisterInfo::isPhysicalRegister(VRM.getPhys(VirtReg))) {
1063 // This can create a %noreg operand in rare cases when the sub-register
1064 // index is no longer available. That means the user value is in a
1065 // non-existent sub-register, and %noreg is exactly what we want.
1066 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
1067 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
1068 // FIXME: Translate SubIdx to a stackslot offset.
1069 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
1070 Spilled = true;
1071 } else {
1072 Loc.setReg(0);
1073 Loc.setSubReg(0);
1074 }
1075 }
1076
1077 // Insert this location if it doesn't already exist and record a mapping
1078 // from the old number to the new number.
1079 auto InsertResult = NewLocations.insert({Loc, Spilled});
1080 unsigned NewLocNo = std::distance(NewLocations.begin(), InsertResult.first);
1081 LocNoMap[I] = NewLocNo;
1082 }
1083
1084 // Rewrite the locations and record which ones were spill slots.
1085 locations.clear();
1086 SpilledLocations.clear();
1087 SpilledLocations.resize(NewLocations.size());
1088 for (auto &Pair : NewLocations) {
1089 locations.push_back(Pair.first);
1090 if (Pair.second) {
1091 unsigned NewLocNo = std::distance(&*NewLocations.begin(), &Pair);
1092 SpilledLocations.set(NewLocNo);
1093 }
1094 }
1095
1096 // Update the interval map, but only coalesce left, since intervals to the
1097 // right use the old location numbers. This should merge two contiguous
1098 // DBG_VALUE intervals with different vregs that were allocated to the same
1099 // physical register.
1100 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
1101 DbgValueLocation Loc = I.value();
1102 // Undef values don't exist in locations (and thus not in LocNoMap either)
1103 // so skip over them. See getLocationNo().
1104 if (Loc.isUndef())
1105 continue;
1106 unsigned NewLocNo = LocNoMap[Loc.locNo()];
1107 I.setValueUnchecked(Loc.changeLocNo(NewLocNo));
1108 I.setStart(I.start());
1109 }
1110}
1111
1112/// Find an iterator for inserting a DBG_VALUE instruction.
1113static MachineBasicBlock::iterator
1114findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
1115 LiveIntervals &LIS) {
1116 SlotIndex Start = LIS.getMBBStartIdx(MBB);
1117 Idx = Idx.getBaseIndex();
1118
1119 // Try to find an insert location by going backwards from Idx.
1120 MachineInstr *MI;
1121 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
1122 // We've reached the beginning of MBB.
1123 if (Idx == Start) {
1124 MachineBasicBlock::iterator I = MBB->SkipPHIsLabelsAndDebug(MBB->begin());
1125 return I;
1126 }
1127 Idx = Idx.getPrevIndex();
1128 }
1129
1130 // Don't insert anything after the first terminator, though.
1131 return MI->isTerminator() ? MBB->getFirstTerminator() :
1132 std::next(MachineBasicBlock::iterator(MI));
1133}
1134
1135/// Find an iterator for inserting the next DBG_VALUE instruction
1136/// (or end if no more insert locations found).
1137static MachineBasicBlock::iterator
1138findNextInsertLocation(MachineBasicBlock *MBB,
1139 MachineBasicBlock::iterator I,
1140 SlotIndex StopIdx, MachineOperand &LocMO,
1141 LiveIntervals &LIS,
1142 const TargetRegisterInfo &TRI) {
1143 if (!LocMO.isReg())
1144 return MBB->instr_end();
1145 unsigned Reg = LocMO.getReg();
1146
1147 // Find the next instruction in the MBB that define the register Reg.
1148 while (I != MBB->end() && !I->isTerminator()) {
1149 if (!LIS.isNotInMIMap(*I) &&
1150 SlotIndex::isEarlierEqualInstr(StopIdx, LIS.getInstructionIndex(*I)))
1151 break;
1152 if (I->definesRegister(Reg, &TRI))
1153 // The insert location is directly after the instruction/bundle.
1154 return std::next(I);
1155 ++I;
1156 }
1157 return MBB->end();
1158}
1159
1160void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
1161 SlotIndex StopIdx,
1162 DbgValueLocation Loc, bool Spilled,
1163 LiveIntervals &LIS,
1164 const TargetInstrInfo &TII,
1165 const TargetRegisterInfo &TRI) {
1166 SlotIndex MBBEndIdx = LIS.getMBBEndIdx(&*MBB);
1167 // Only search within the current MBB.
1168 StopIdx = (MBBEndIdx < StopIdx) ? MBBEndIdx : StopIdx;
1169 MachineBasicBlock::iterator I = findInsertLocation(MBB, StartIdx, LIS);
1170 // Undef values don't exist in locations so create new "noreg" register MOs
1171 // for them. See getLocationNo().
1172 MachineOperand MO = !Loc.isUndef() ?
1173 locations[Loc.locNo()] :
1174 MachineOperand::CreateReg(/* Reg */ 0, /* isDef */ false, /* isImp */ false,
1175 /* isKill */ false, /* isDead */ false,
1176 /* isUndef */ false, /* isEarlyClobber */ false,
1177 /* SubReg */ 0, /* isDebug */ true);
1178
1179 ++NumInsertedDebugValues;
1180
1181 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~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 1183, __extension__ __PRETTY_FUNCTION__))
1182 ->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~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 1183, __extension__ __PRETTY_FUNCTION__))
1183 "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~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 1183, __extension__ __PRETTY_FUNCTION__))
;
1184
1185 // If the location was spilled, the new DBG_VALUE will be indirect. If the
1186 // original DBG_VALUE was indirect, we need to add DW_OP_deref to indicate
1187 // that the original virtual register was a pointer.
1188 const DIExpression *Expr = Expression;
1189 bool IsIndirect = Loc.wasIndirect();
1190 if (Spilled) {
1191 if (IsIndirect)
1192 Expr = DIExpression::prepend(Expr, DIExpression::WithDeref);
1193 IsIndirect = true;
1194 }
1195
1196 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~svn338205/lib/CodeGen/LiveDebugVariables.cpp"
, 1196, __extension__ __PRETTY_FUNCTION__))
;
1197
1198 do {
1199 BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
1200 IsIndirect, MO, Variable, Expr);
1201
1202 // Continue and insert DBG_VALUES after every redefinition of register
1203 // associated with the debug value within the range
1204 I = findNextInsertLocation(MBB, I, StopIdx, MO, LIS, TRI);
1205 } while (I != MBB->end());
1206}
1207
1208void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
1209 const TargetInstrInfo &TII,
1210 const TargetRegisterInfo &TRI,
1211 const BitVector &SpilledLocations) {
1212 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
1213
1214 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
1215 SlotIndex Start = I.start();
1216 SlotIndex Stop = I.stop();
1217 DbgValueLocation Loc = I.value();
1218 bool Spilled = !Loc.isUndef() ? SpilledLocations.test(Loc.locNo()) : false;
1219
1220 // If the interval start was trimmed to the lexical scope insert the
1221 // DBG_VALUE at the previous index (otherwise it appears after the
1222 // first instruction in the range).
1223 if (trimmedDefs.count(Start))
1224 Start = Start.getPrevIndex();
1225
1226 LLVM_DEBUG(dbgs() << "\t[" << Start << ';' << Stop << "):" << Loc.locNo())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "\t[" << Start <<
';' << Stop << "):" << Loc.locNo(); } } while
(false)
;
1227 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start)->getIterator();
1228 SlotIndex MBBEnd = LIS.getMBBEndIdx(&*MBB);
1229
1230 LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB) << '-' << MBBEnd; } } while (false)
;
1231 insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, LIS, TII, TRI);
1232 // This interval may span multiple basic blocks.
1233 // Insert a DBG_VALUE into each one.
1234 while (Stop > MBBEnd) {
1235 // Move to the next block.
1236 Start = MBBEnd;
1237 if (++MBB == MFEnd)
1238 break;
1239 MBBEnd = LIS.getMBBEndIdx(&*MBB);
1240 LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB) << '-' << MBBEnd; } } while (false)
;
1241 insertDebugValue(&*MBB, Start, Stop, Loc, Spilled, LIS, TII, TRI);
1242 }
1243 LLVM_DEBUG(dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << '\n'; } } while (false)
;
1244 if (MBB == MFEnd)
1245 break;
1246
1247 ++I;
1248 }
1249}
1250
1251void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
1252 LLVM_DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n"
; } } while (false)
;
1253 if (!MF)
1254 return;
1255 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
1256 BitVector SpilledLocations;
1257 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
1258 LLVM_DEBUG(userValues[i]->print(dbgs(), TRI))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { userValues[i]->print(dbgs(), TRI); } }
while (false)
;
1259 userValues[i]->rewriteLocations(*VRM, *TRI, SpilledLocations);
1260 userValues[i]->emitDebugValues(VRM, *LIS, *TII, *TRI, SpilledLocations);
1261 }
1262 EmitDone = true;
1263}
1264
1265void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
1266 if (pImpl)
1267 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
1268}
1269
1270bool LiveDebugVariables::doInitialization(Module &M) {
1271 return Pass::doInitialization(M);
1272}
1273
1274#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1275LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void LiveDebugVariables::dump() const {
1276 if (pImpl)
1277 static_cast<LDVImpl*>(pImpl)->print(dbgs());
1278}
1279#endif