Bug Summary

File:llvm/lib/CodeGen/LiveDebugVariables.cpp
Warning:line 223, column 55
Dereference of null pointer

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -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 -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I lib/CodeGen -I /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/llvm/lib/CodeGen -I include -I /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/llvm/include -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm=build-llvm -fmacro-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/= -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm=build-llvm -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/= -O3 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/build-llvm=build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2022-01-16-232930-107970-1 -x c++ /build/llvm-toolchain-snapshot-14~++20220116100644+5f782d25a742/llvm/lib/CodeGen/LiveDebugVariables.cpp
1//===- LiveDebugVariables.cpp - Tracking debug info variables -------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the LiveDebugVariables analysis.
10//
11// Remove all DBG_VALUE instructions referencing virtual registers and replace
12// them with a data structure tracking where live user variables are kept - in a
13// virtual register or in a stack slot.
14//
15// Allow the data structure to be updated during register allocation when values
16// are moved between registers and stack slots. Finally emit new DBG_VALUE
17// instructions after register allocation is complete.
18//
19//===----------------------------------------------------------------------===//
20
21#include "LiveDebugVariables.h"
22#include "llvm/ADT/ArrayRef.h"
23#include "llvm/ADT/DenseMap.h"
24#include "llvm/ADT/IntervalMap.h"
25#include "llvm/ADT/MapVector.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/Passes.h"
42#include "llvm/CodeGen/SlotIndexes.h"
43#include "llvm/CodeGen/TargetInstrInfo.h"
44#include "llvm/CodeGen/TargetOpcodes.h"
45#include "llvm/CodeGen/TargetPassConfig.h"
46#include "llvm/CodeGen/TargetRegisterInfo.h"
47#include "llvm/CodeGen/TargetSubtargetInfo.h"
48#include "llvm/CodeGen/VirtRegMap.h"
49#include "llvm/Config/llvm-config.h"
50#include "llvm/IR/DebugInfoMetadata.h"
51#include "llvm/IR/DebugLoc.h"
52#include "llvm/IR/Function.h"
53#include "llvm/IR/Metadata.h"
54#include "llvm/InitializePasses.h"
55#include "llvm/MC/MCRegisterInfo.h"
56#include "llvm/Pass.h"
57#include "llvm/Support/Casting.h"
58#include "llvm/Support/CommandLine.h"
59#include "llvm/Support/Debug.h"
60#include "llvm/Support/raw_ostream.h"
61#include "llvm/Target/TargetMachine.h"
62#include <algorithm>
63#include <cassert>
64#include <iterator>
65#include <memory>
66#include <utility>
67
68using namespace llvm;
69
70#define DEBUG_TYPE"livedebugvars" "livedebugvars"
71
72static cl::opt<bool>
73EnableLDV("live-debug-variables", cl::init(true),
74 cl::desc("Enable the live debug variables pass"), cl::Hidden);
75
76STATISTIC(NumInsertedDebugValues, "Number of DBG_VALUEs inserted")static llvm::Statistic NumInsertedDebugValues = {"livedebugvars"
, "NumInsertedDebugValues", "Number of DBG_VALUEs inserted"}
;
77STATISTIC(NumInsertedDebugLabels, "Number of DBG_LABELs inserted")static llvm::Statistic NumInsertedDebugLabels = {"livedebugvars"
, "NumInsertedDebugLabels", "Number of DBG_LABELs inserted"}
;
78
79char LiveDebugVariables::ID = 0;
80
81INITIALIZE_PASS_BEGIN(LiveDebugVariables, DEBUG_TYPE,static void *initializeLiveDebugVariablesPassOnce(PassRegistry
&Registry) {
82 "Debug Variable Analysis", false, false)static void *initializeLiveDebugVariablesPassOnce(PassRegistry
&Registry) {
83INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)initializeMachineDominatorTreePass(Registry);
84INITIALIZE_PASS_DEPENDENCY(LiveIntervals)initializeLiveIntervalsPass(Registry);
85INITIALIZE_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)); }
86 "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)); }
87
88void LiveDebugVariables::getAnalysisUsage(AnalysisUsage &AU) const {
89 AU.addRequired<MachineDominatorTree>();
90 AU.addRequiredTransitive<LiveIntervals>();
91 AU.setPreservesAll();
92 MachineFunctionPass::getAnalysisUsage(AU);
93}
94
95LiveDebugVariables::LiveDebugVariables() : MachineFunctionPass(ID) {
96 initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
97}
98
99enum : unsigned { UndefLocNo = ~0U };
100
101namespace {
102/// Describes a debug variable value by location number and expression along
103/// with some flags about the original usage of the location.
104class DbgVariableValue {
105public:
106 DbgVariableValue(ArrayRef<unsigned> NewLocs, bool WasIndirect, bool WasList,
107 const DIExpression &Expr)
108 : WasIndirect(WasIndirect), WasList(WasList), Expression(&Expr) {
109 assert(!(WasIndirect && WasList) &&(static_cast <bool> (!(WasIndirect && WasList) &&
"DBG_VALUE_LISTs should not be indirect.") ? void (0) : __assert_fail
("!(WasIndirect && WasList) && \"DBG_VALUE_LISTs should not be indirect.\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 110, __extension__
__PRETTY_FUNCTION__))
110 "DBG_VALUE_LISTs should not be indirect.")(static_cast <bool> (!(WasIndirect && WasList) &&
"DBG_VALUE_LISTs should not be indirect.") ? void (0) : __assert_fail
("!(WasIndirect && WasList) && \"DBG_VALUE_LISTs should not be indirect.\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 110, __extension__
__PRETTY_FUNCTION__))
;
111 SmallVector<unsigned> LocNoVec;
112 for (unsigned LocNo : NewLocs) {
113 auto It = find(LocNoVec, LocNo);
114 if (It == LocNoVec.end())
115 LocNoVec.push_back(LocNo);
116 else {
117 // Loc duplicates an element in LocNos; replace references to Op
118 // with references to the duplicating element.
119 unsigned OpIdx = LocNoVec.size();
120 unsigned DuplicatingIdx = std::distance(LocNoVec.begin(), It);
121 Expression =
122 DIExpression::replaceArg(Expression, OpIdx, DuplicatingIdx);
123 }
124 }
125 // FIXME: Debug values referencing 64+ unique machine locations are rare and
126 // currently unsupported for performance reasons. If we can verify that
127 // performance is acceptable for such debug values, we can increase the
128 // bit-width of LocNoCount to 14 to enable up to 16384 unique machine
129 // locations. We will also need to verify that this does not cause issues
130 // with LiveDebugVariables' use of IntervalMap.
131 if (LocNoVec.size() < 64) {
132 LocNoCount = LocNoVec.size();
133 if (LocNoCount > 0) {
134 LocNos = std::make_unique<unsigned[]>(LocNoCount);
135 std::copy(LocNoVec.begin(), LocNoVec.end(), loc_nos_begin());
136 }
137 } else {
138 LLVM_DEBUG(dbgs() << "Found debug value with 64+ unique machine "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Found debug value with 64+ unique machine "
"locations, dropping...\n"; } } while (false)
139 "locations, dropping...\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Found debug value with 64+ unique machine "
"locations, dropping...\n"; } } while (false)
;
140 LocNoCount = 1;
141 // Turn this into an undef debug value list; right now, the simplest form
142 // of this is an expression with one arg, and an undef debug operand.
143 Expression =
144 DIExpression::get(Expr.getContext(), {dwarf::DW_OP_LLVM_arg, 0,
145 dwarf::DW_OP_stack_value});
146 if (auto FragmentInfoOpt = Expr.getFragmentInfo())
147 Expression = *DIExpression::createFragmentExpression(
148 Expression, FragmentInfoOpt->OffsetInBits,
149 FragmentInfoOpt->SizeInBits);
150 LocNos = std::make_unique<unsigned[]>(LocNoCount);
151 LocNos[0] = UndefLocNo;
152 }
153 }
154
155 DbgVariableValue() : LocNoCount(0), WasIndirect(false), WasList(false) {}
156 DbgVariableValue(const DbgVariableValue &Other)
157 : LocNoCount(Other.LocNoCount), WasIndirect(Other.getWasIndirect()),
158 WasList(Other.getWasList()), Expression(Other.getExpression()) {
159 if (Other.getLocNoCount()) {
160 LocNos.reset(new unsigned[Other.getLocNoCount()]);
161 std::copy(Other.loc_nos_begin(), Other.loc_nos_end(), loc_nos_begin());
162 }
163 }
164
165 DbgVariableValue &operator=(const DbgVariableValue &Other) {
166 if (this == &Other)
167 return *this;
168 if (Other.getLocNoCount()) {
169 LocNos.reset(new unsigned[Other.getLocNoCount()]);
170 std::copy(Other.loc_nos_begin(), Other.loc_nos_end(), loc_nos_begin());
171 } else {
172 LocNos.release();
173 }
174 LocNoCount = Other.getLocNoCount();
175 WasIndirect = Other.getWasIndirect();
176 WasList = Other.getWasList();
177 Expression = Other.getExpression();
178 return *this;
179 }
180
181 const DIExpression *getExpression() const { return Expression; }
182 uint8_t getLocNoCount() const { return LocNoCount; }
183 bool containsLocNo(unsigned LocNo) const {
184 return is_contained(loc_nos(), LocNo);
185 }
186 bool getWasIndirect() const { return WasIndirect; }
187 bool getWasList() const { return WasList; }
188 bool isUndef() const { return LocNoCount == 0 || containsLocNo(UndefLocNo); }
189
190 DbgVariableValue decrementLocNosAfterPivot(unsigned Pivot) const {
191 SmallVector<unsigned, 4> NewLocNos;
192 for (unsigned LocNo : loc_nos())
193 NewLocNos.push_back(LocNo != UndefLocNo && LocNo > Pivot ? LocNo - 1
194 : LocNo);
195 return DbgVariableValue(NewLocNos, WasIndirect, WasList, *Expression);
196 }
197
198 DbgVariableValue remapLocNos(ArrayRef<unsigned> LocNoMap) const {
199 SmallVector<unsigned> NewLocNos;
200 for (unsigned LocNo : loc_nos())
201 // Undef values don't exist in locations (and thus not in LocNoMap
202 // either) so skip over them. See getLocationNo().
203 NewLocNos.push_back(LocNo == UndefLocNo ? UndefLocNo : LocNoMap[LocNo]);
204 return DbgVariableValue(NewLocNos, WasIndirect, WasList, *Expression);
205 }
206
207 DbgVariableValue changeLocNo(unsigned OldLocNo, unsigned NewLocNo) const {
208 SmallVector<unsigned> NewLocNos;
209 NewLocNos.assign(loc_nos_begin(), loc_nos_end());
210 auto OldLocIt = find(NewLocNos, OldLocNo);
211 assert(OldLocIt != NewLocNos.end() && "Old location must be present.")(static_cast <bool> (OldLocIt != NewLocNos.end() &&
"Old location must be present.") ? void (0) : __assert_fail (
"OldLocIt != NewLocNos.end() && \"Old location must be present.\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 211, __extension__
__PRETTY_FUNCTION__))
;
212 *OldLocIt = NewLocNo;
213 return DbgVariableValue(NewLocNos, WasIndirect, WasList, *Expression);
214 }
215
216 bool hasLocNoGreaterThan(unsigned LocNo) const {
217 return any_of(loc_nos(),
218 [LocNo](unsigned ThisLocNo) { return ThisLocNo > LocNo; });
219 }
220
221 void printLocNos(llvm::raw_ostream &OS) const {
222 for (const unsigned &Loc : loc_nos())
20
Assuming '__begin2' is not equal to '__end2'
21
'Loc' initialized to the value of '__begin2'
223 OS << (&Loc == loc_nos_begin() ? " " : ", ") << Loc;
22
Assuming pointer value is null
23
'?' condition is true
24
Dereference of null pointer
224 }
225
226 friend inline bool operator==(const DbgVariableValue &LHS,
227 const DbgVariableValue &RHS) {
228 if (std::tie(LHS.LocNoCount, LHS.WasIndirect, LHS.WasList,
229 LHS.Expression) !=
230 std::tie(RHS.LocNoCount, RHS.WasIndirect, RHS.WasList, RHS.Expression))
231 return false;
232 return std::equal(LHS.loc_nos_begin(), LHS.loc_nos_end(),
233 RHS.loc_nos_begin());
234 }
235
236 friend inline bool operator!=(const DbgVariableValue &LHS,
237 const DbgVariableValue &RHS) {
238 return !(LHS == RHS);
239 }
240
241 unsigned *loc_nos_begin() { return LocNos.get(); }
242 const unsigned *loc_nos_begin() const { return LocNos.get(); }
243 unsigned *loc_nos_end() { return LocNos.get() + LocNoCount; }
244 const unsigned *loc_nos_end() const { return LocNos.get() + LocNoCount; }
245 ArrayRef<unsigned> loc_nos() const {
246 return ArrayRef<unsigned>(LocNos.get(), LocNoCount);
247 }
248
249private:
250 // IntervalMap requires the value object to be very small, to the extent
251 // that we do not have enough room for an std::vector. Using a C-style array
252 // (with a unique_ptr wrapper for convenience) allows us to optimize for this
253 // specific case by packing the array size into only 6 bits (it is highly
254 // unlikely that any debug value will need 64+ locations).
255 std::unique_ptr<unsigned[]> LocNos;
256 uint8_t LocNoCount : 6;
257 bool WasIndirect : 1;
258 bool WasList : 1;
259 const DIExpression *Expression = nullptr;
260};
261} // namespace
262
263/// Map of where a user value is live to that value.
264using LocMap = IntervalMap<SlotIndex, DbgVariableValue, 4>;
265
266/// Map of stack slot offsets for spilled locations.
267/// Non-spilled locations are not added to the map.
268using SpillOffsetMap = DenseMap<unsigned, unsigned>;
269
270/// Cache to save the location where it can be used as the starting
271/// position as input for calling MachineBasicBlock::SkipPHIsLabelsAndDebug.
272/// This is to prevent MachineBasicBlock::SkipPHIsLabelsAndDebug from
273/// repeatedly searching the same set of PHIs/Labels/Debug instructions
274/// if it is called many times for the same block.
275using BlockSkipInstsMap =
276 DenseMap<MachineBasicBlock *, MachineBasicBlock::iterator>;
277
278namespace {
279
280class LDVImpl;
281
282/// A user value is a part of a debug info user variable.
283///
284/// A DBG_VALUE instruction notes that (a sub-register of) a virtual register
285/// holds part of a user variable. The part is identified by a byte offset.
286///
287/// UserValues are grouped into equivalence classes for easier searching. Two
288/// user values are related if they are held by the same virtual register. The
289/// equivalence class is the transitive closure of that relation.
290class UserValue {
291 const DILocalVariable *Variable; ///< The debug info variable we are part of.
292 /// The part of the variable we describe.
293 const Optional<DIExpression::FragmentInfo> Fragment;
294 DebugLoc dl; ///< The debug location for the variable. This is
295 ///< used by dwarf writer to find lexical scope.
296 UserValue *leader; ///< Equivalence class leader.
297 UserValue *next = nullptr; ///< Next value in equivalence class, or null.
298
299 /// Numbered locations referenced by locmap.
300 SmallVector<MachineOperand, 4> locations;
301
302 /// Map of slot indices where this value is live.
303 LocMap locInts;
304
305 /// Set of interval start indexes that have been trimmed to the
306 /// lexical scope.
307 SmallSet<SlotIndex, 2> trimmedDefs;
308
309 /// Insert a DBG_VALUE into MBB at Idx for DbgValue.
310 void insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
311 SlotIndex StopIdx, DbgVariableValue DbgValue,
312 ArrayRef<bool> LocSpills,
313 ArrayRef<unsigned> SpillOffsets, LiveIntervals &LIS,
314 const TargetInstrInfo &TII,
315 const TargetRegisterInfo &TRI,
316 BlockSkipInstsMap &BBSkipInstsMap);
317
318 /// Replace OldLocNo ranges with NewRegs ranges where NewRegs
319 /// is live. Returns true if any changes were made.
320 bool splitLocation(unsigned OldLocNo, ArrayRef<Register> NewRegs,
321 LiveIntervals &LIS);
322
323public:
324 /// Create a new UserValue.
325 UserValue(const DILocalVariable *var,
326 Optional<DIExpression::FragmentInfo> Fragment, DebugLoc L,
327 LocMap::Allocator &alloc)
328 : Variable(var), Fragment(Fragment), dl(std::move(L)), leader(this),
329 locInts(alloc) {}
330
331 /// Get the leader of this value's equivalence class.
332 UserValue *getLeader() {
333 UserValue *l = leader;
334 while (l != l->leader)
335 l = l->leader;
336 return leader = l;
337 }
338
339 /// Return the next UserValue in the equivalence class.
340 UserValue *getNext() const { return next; }
341
342 /// Merge equivalence classes.
343 static UserValue *merge(UserValue *L1, UserValue *L2) {
344 L2 = L2->getLeader();
345 if (!L1)
346 return L2;
347 L1 = L1->getLeader();
348 if (L1 == L2)
349 return L1;
350 // Splice L2 before L1's members.
351 UserValue *End = L2;
352 while (End->next) {
353 End->leader = L1;
354 End = End->next;
355 }
356 End->leader = L1;
357 End->next = L1->next;
358 L1->next = L2;
359 return L1;
360 }
361
362 /// Return the location number that matches Loc.
363 ///
364 /// For undef values we always return location number UndefLocNo without
365 /// inserting anything in locations. Since locations is a vector and the
366 /// location number is the position in the vector and UndefLocNo is ~0,
367 /// we would need a very big vector to put the value at the right position.
368 unsigned getLocationNo(const MachineOperand &LocMO) {
369 if (LocMO.isReg()) {
370 if (LocMO.getReg() == 0)
371 return UndefLocNo;
372 // For register locations we dont care about use/def and other flags.
373 for (unsigned i = 0, e = locations.size(); i != e; ++i)
374 if (locations[i].isReg() &&
375 locations[i].getReg() == LocMO.getReg() &&
376 locations[i].getSubReg() == LocMO.getSubReg())
377 return i;
378 } else
379 for (unsigned i = 0, e = locations.size(); i != e; ++i)
380 if (LocMO.isIdenticalTo(locations[i]))
381 return i;
382 locations.push_back(LocMO);
383 // We are storing a MachineOperand outside a MachineInstr.
384 locations.back().clearParent();
385 // Don't store def operands.
386 if (locations.back().isReg()) {
387 if (locations.back().isDef())
388 locations.back().setIsDead(false);
389 locations.back().setIsUse();
390 }
391 return locations.size() - 1;
392 }
393
394 /// Remove (recycle) a location number. If \p LocNo still is used by the
395 /// locInts nothing is done.
396 void removeLocationIfUnused(unsigned LocNo) {
397 // Bail out if LocNo still is used.
398 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
399 const DbgVariableValue &DbgValue = I.value();
400 if (DbgValue.containsLocNo(LocNo))
401 return;
402 }
403 // Remove the entry in the locations vector, and adjust all references to
404 // location numbers above the removed entry.
405 locations.erase(locations.begin() + LocNo);
406 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
407 const DbgVariableValue &DbgValue = I.value();
408 if (DbgValue.hasLocNoGreaterThan(LocNo))
409 I.setValueUnchecked(DbgValue.decrementLocNosAfterPivot(LocNo));
410 }
411 }
412
413 /// Ensure that all virtual register locations are mapped.
414 void mapVirtRegs(LDVImpl *LDV);
415
416 /// Add a definition point to this user value.
417 void addDef(SlotIndex Idx, ArrayRef<MachineOperand> LocMOs, bool IsIndirect,
418 bool IsList, const DIExpression &Expr) {
419 SmallVector<unsigned> Locs;
420 for (const MachineOperand &Op : LocMOs)
421 Locs.push_back(getLocationNo(Op));
422 DbgVariableValue DbgValue(Locs, IsIndirect, IsList, Expr);
423 // Add a singular (Idx,Idx) -> value mapping.
424 LocMap::iterator I = locInts.find(Idx);
425 if (!I.valid() || I.start() != Idx)
426 I.insert(Idx, Idx.getNextSlot(), std::move(DbgValue));
427 else
428 // A later DBG_VALUE at the same SlotIndex overrides the old location.
429 I.setValue(std::move(DbgValue));
430 }
431
432 /// Extend the current definition as far as possible down.
433 ///
434 /// Stop when meeting an existing def or when leaving the live
435 /// range of VNI. End points where VNI is no longer live are added to Kills.
436 ///
437 /// We only propagate DBG_VALUES locally here. LiveDebugValues performs a
438 /// data-flow analysis to propagate them beyond basic block boundaries.
439 ///
440 /// \param Idx Starting point for the definition.
441 /// \param DbgValue value to propagate.
442 /// \param LiveIntervalInfo For each location number key in this map,
443 /// restricts liveness to where the LiveRange has the value equal to the\
444 /// VNInfo.
445 /// \param [out] Kills Append end points of VNI's live range to Kills.
446 /// \param LIS Live intervals analysis.
447 void extendDef(SlotIndex Idx, DbgVariableValue DbgValue,
448 SmallDenseMap<unsigned, std::pair<LiveRange *, const VNInfo *>>
449 &LiveIntervalInfo,
450 Optional<std::pair<SlotIndex, SmallVector<unsigned>>> &Kills,
451 LiveIntervals &LIS);
452
453 /// The value in LI may be copies to other registers. Determine if
454 /// any of the copies are available at the kill points, and add defs if
455 /// possible.
456 ///
457 /// \param DbgValue Location number of LI->reg, and DIExpression.
458 /// \param LocIntervals Scan for copies of the value for each location in the
459 /// corresponding LiveInterval->reg.
460 /// \param KilledAt The point where the range of DbgValue could be extended.
461 /// \param [in,out] NewDefs Append (Idx, DbgValue) of inserted defs here.
462 void addDefsFromCopies(
463 DbgVariableValue DbgValue,
464 SmallVectorImpl<std::pair<unsigned, LiveInterval *>> &LocIntervals,
465 SlotIndex KilledAt,
466 SmallVectorImpl<std::pair<SlotIndex, DbgVariableValue>> &NewDefs,
467 MachineRegisterInfo &MRI, LiveIntervals &LIS);
468
469 /// Compute the live intervals of all locations after collecting all their
470 /// def points.
471 void computeIntervals(MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
472 LiveIntervals &LIS, LexicalScopes &LS);
473
474 /// Replace OldReg ranges with NewRegs ranges where NewRegs is
475 /// live. Returns true if any changes were made.
476 bool splitRegister(Register OldReg, ArrayRef<Register> NewRegs,
477 LiveIntervals &LIS);
478
479 /// Rewrite virtual register locations according to the provided virtual
480 /// register map. Record the stack slot offsets for the locations that
481 /// were spilled.
482 void rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF,
483 const TargetInstrInfo &TII,
484 const TargetRegisterInfo &TRI,
485 SpillOffsetMap &SpillOffsets);
486
487 /// Recreate DBG_VALUE instruction from data structures.
488 void emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
489 const TargetInstrInfo &TII,
490 const TargetRegisterInfo &TRI,
491 const SpillOffsetMap &SpillOffsets,
492 BlockSkipInstsMap &BBSkipInstsMap);
493
494 /// Return DebugLoc of this UserValue.
495 const DebugLoc &getDebugLoc() { return dl; }
496
497 void print(raw_ostream &, const TargetRegisterInfo *);
498};
499
500/// A user label is a part of a debug info user label.
501class UserLabel {
502 const DILabel *Label; ///< The debug info label we are part of.
503 DebugLoc dl; ///< The debug location for the label. This is
504 ///< used by dwarf writer to find lexical scope.
505 SlotIndex loc; ///< Slot used by the debug label.
506
507 /// Insert a DBG_LABEL into MBB at Idx.
508 void insertDebugLabel(MachineBasicBlock *MBB, SlotIndex Idx,
509 LiveIntervals &LIS, const TargetInstrInfo &TII,
510 BlockSkipInstsMap &BBSkipInstsMap);
511
512public:
513 /// Create a new UserLabel.
514 UserLabel(const DILabel *label, DebugLoc L, SlotIndex Idx)
515 : Label(label), dl(std::move(L)), loc(Idx) {}
516
517 /// Does this UserLabel match the parameters?
518 bool matches(const DILabel *L, const DILocation *IA,
519 const SlotIndex Index) const {
520 return Label == L && dl->getInlinedAt() == IA && loc == Index;
521 }
522
523 /// Recreate DBG_LABEL instruction from data structures.
524 void emitDebugLabel(LiveIntervals &LIS, const TargetInstrInfo &TII,
525 BlockSkipInstsMap &BBSkipInstsMap);
526
527 /// Return DebugLoc of this UserLabel.
528 const DebugLoc &getDebugLoc() { return dl; }
529
530 void print(raw_ostream &, const TargetRegisterInfo *);
531};
532
533/// Implementation of the LiveDebugVariables pass.
534class LDVImpl {
535 LiveDebugVariables &pass;
536 LocMap::Allocator allocator;
537 MachineFunction *MF = nullptr;
538 LiveIntervals *LIS;
539 const TargetRegisterInfo *TRI;
540
541 /// Position and VReg of a PHI instruction during register allocation.
542 struct PHIValPos {
543 SlotIndex SI; /// Slot where this PHI occurs.
544 Register Reg; /// VReg this PHI occurs in.
545 unsigned SubReg; /// Qualifiying subregister for Reg.
546 };
547
548 /// Map from debug instruction number to PHI position during allocation.
549 std::map<unsigned, PHIValPos> PHIValToPos;
550 /// Index of, for each VReg, which debug instruction numbers and corresponding
551 /// PHIs are sensitive to splitting. Each VReg may have multiple PHI defs,
552 /// at different positions.
553 DenseMap<Register, std::vector<unsigned>> RegToPHIIdx;
554
555 /// Record for any debug instructions unlinked from their blocks during
556 /// regalloc. Stores the instr and it's location, so that they can be
557 /// re-inserted after regalloc is over.
558 struct InstrPos {
559 MachineInstr *MI; ///< Debug instruction, unlinked from it's block.
560 SlotIndex Idx; ///< Slot position where MI should be re-inserted.
561 MachineBasicBlock *MBB; ///< Block that MI was in.
562 };
563
564 /// Collection of stored debug instructions, preserved until after regalloc.
565 SmallVector<InstrPos, 32> StashedDebugInstrs;
566
567 /// Whether emitDebugValues is called.
568 bool EmitDone = false;
569
570 /// Whether the machine function is modified during the pass.
571 bool ModifiedMF = false;
572
573 /// All allocated UserValue instances.
574 SmallVector<std::unique_ptr<UserValue>, 8> userValues;
575
576 /// All allocated UserLabel instances.
577 SmallVector<std::unique_ptr<UserLabel>, 2> userLabels;
578
579 /// Map virtual register to eq class leader.
580 using VRMap = DenseMap<unsigned, UserValue *>;
581 VRMap virtRegToEqClass;
582
583 /// Map to find existing UserValue instances.
584 using UVMap = DenseMap<DebugVariable, UserValue *>;
585 UVMap userVarMap;
586
587 /// Find or create a UserValue.
588 UserValue *getUserValue(const DILocalVariable *Var,
589 Optional<DIExpression::FragmentInfo> Fragment,
590 const DebugLoc &DL);
591
592 /// Find the EC leader for VirtReg or null.
593 UserValue *lookupVirtReg(Register VirtReg);
594
595 /// Add DBG_VALUE instruction to our maps.
596 ///
597 /// \param MI DBG_VALUE instruction
598 /// \param Idx Last valid SLotIndex before instruction.
599 ///
600 /// \returns True if the DBG_VALUE instruction should be deleted.
601 bool handleDebugValue(MachineInstr &MI, SlotIndex Idx);
602
603 /// Track variable location debug instructions while using the instruction
604 /// referencing implementation. Such debug instructions do not need to be
605 /// updated during regalloc because they identify instructions rather than
606 /// register locations. However, they needs to be removed from the
607 /// MachineFunction during regalloc, then re-inserted later, to avoid
608 /// disrupting the allocator.
609 ///
610 /// \param MI Any DBG_VALUE / DBG_INSTR_REF / DBG_PHI instruction
611 /// \param Idx Last valid SlotIndex before instruction
612 ///
613 /// \returns Iterator to continue processing from after unlinking.
614 MachineBasicBlock::iterator handleDebugInstr(MachineInstr &MI, SlotIndex Idx);
615
616 /// Add DBG_LABEL instruction to UserLabel.
617 ///
618 /// \param MI DBG_LABEL instruction
619 /// \param Idx Last valid SlotIndex before instruction.
620 ///
621 /// \returns True if the DBG_LABEL instruction should be deleted.
622 bool handleDebugLabel(MachineInstr &MI, SlotIndex Idx);
623
624 /// Collect and erase all DBG_VALUE instructions, adding a UserValue def
625 /// for each instruction.
626 ///
627 /// \param mf MachineFunction to be scanned.
628 /// \param InstrRef Whether to operate in instruction referencing mode. If
629 /// true, most of LiveDebugVariables doesn't run.
630 ///
631 /// \returns True if any debug values were found.
632 bool collectDebugValues(MachineFunction &mf, bool InstrRef);
633
634 /// Compute the live intervals of all user values after collecting all
635 /// their def points.
636 void computeIntervals();
637
638public:
639 LDVImpl(LiveDebugVariables *ps) : pass(*ps) {}
640
641 bool runOnMachineFunction(MachineFunction &mf, bool InstrRef);
642
643 /// Release all memory.
644 void clear() {
645 MF = nullptr;
646 PHIValToPos.clear();
647 RegToPHIIdx.clear();
648 StashedDebugInstrs.clear();
649 userValues.clear();
650 userLabels.clear();
651 virtRegToEqClass.clear();
652 userVarMap.clear();
653 // Make sure we call emitDebugValues if the machine function was modified.
654 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\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 655, __extension__
__PRETTY_FUNCTION__))
655 "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\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 655, __extension__
__PRETTY_FUNCTION__))
;
656 EmitDone = false;
657 ModifiedMF = false;
658 }
659
660 /// Map virtual register to an equivalence class.
661 void mapVirtReg(Register VirtReg, UserValue *EC);
662
663 /// Replace any PHI referring to OldReg with its corresponding NewReg, if
664 /// present.
665 void splitPHIRegister(Register OldReg, ArrayRef<Register> NewRegs);
666
667 /// Replace all references to OldReg with NewRegs.
668 void splitRegister(Register OldReg, ArrayRef<Register> NewRegs);
669
670 /// Recreate DBG_VALUE instruction from data structures.
671 void emitDebugValues(VirtRegMap *VRM);
672
673 void print(raw_ostream&);
674};
675
676} // end anonymous namespace
677
678#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
679static void printDebugLoc(const DebugLoc &DL, raw_ostream &CommentOS,
680 const LLVMContext &Ctx) {
681 if (!DL)
682 return;
683
684 auto *Scope = cast<DIScope>(DL.getScope());
685 // Omit the directory, because it's likely to be long and uninteresting.
686 CommentOS << Scope->getFilename();
687 CommentOS << ':' << DL.getLine();
688 if (DL.getCol() != 0)
689 CommentOS << ':' << DL.getCol();
690
691 DebugLoc InlinedAtDL = DL.getInlinedAt();
692 if (!InlinedAtDL)
693 return;
694
695 CommentOS << " @[ ";
696 printDebugLoc(InlinedAtDL, CommentOS, Ctx);
697 CommentOS << " ]";
698}
699
700static void printExtendedName(raw_ostream &OS, const DINode *Node,
701 const DILocation *DL) {
702 const LLVMContext &Ctx = Node->getContext();
703 StringRef Res;
704 unsigned Line = 0;
705 if (const auto *V = dyn_cast<const DILocalVariable>(Node)) {
706 Res = V->getName();
707 Line = V->getLine();
708 } else if (const auto *L = dyn_cast<const DILabel>(Node)) {
709 Res = L->getName();
710 Line = L->getLine();
711 }
712
713 if (!Res.empty())
714 OS << Res << "," << Line;
715 auto *InlinedAt = DL ? DL->getInlinedAt() : nullptr;
716 if (InlinedAt) {
717 if (DebugLoc InlinedAtDL = InlinedAt) {
718 OS << " @[";
719 printDebugLoc(InlinedAtDL, OS, Ctx);
720 OS << "]";
721 }
722 }
723}
724
725void UserValue::print(raw_ostream &OS, const TargetRegisterInfo *TRI) {
726 OS << "!\"";
727 printExtendedName(OS, Variable, dl);
728
729 OS << "\"\t";
730 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) {
731 OS << " [" << I.start() << ';' << I.stop() << "):";
732 if (I.value().isUndef())
733 OS << " undef";
734 else {
735 I.value().printLocNos(OS);
736 if (I.value().getWasIndirect())
737 OS << " ind";
738 else if (I.value().getWasList())
739 OS << " list";
740 }
741 }
742 for (unsigned i = 0, e = locations.size(); i != e; ++i) {
743 OS << " Loc" << i << '=';
744 locations[i].print(OS, TRI);
745 }
746 OS << '\n';
747}
748
749void UserLabel::print(raw_ostream &OS, const TargetRegisterInfo *TRI) {
750 OS << "!\"";
751 printExtendedName(OS, Label, dl);
752
753 OS << "\"\t";
754 OS << loc;
755 OS << '\n';
756}
757
758void LDVImpl::print(raw_ostream &OS) {
759 OS << "********** DEBUG VARIABLES **********\n";
760 for (auto &userValue : userValues)
761 userValue->print(OS, TRI);
762 OS << "********** DEBUG LABELS **********\n";
763 for (auto &userLabel : userLabels)
764 userLabel->print(OS, TRI);
765}
766#endif
767
768void UserValue::mapVirtRegs(LDVImpl *LDV) {
769 for (unsigned i = 0, e = locations.size(); i != e; ++i)
770 if (locations[i].isReg() &&
771 Register::isVirtualRegister(locations[i].getReg()))
772 LDV->mapVirtReg(locations[i].getReg(), this);
773}
774
775UserValue *LDVImpl::getUserValue(const DILocalVariable *Var,
776 Optional<DIExpression::FragmentInfo> Fragment,
777 const DebugLoc &DL) {
778 // FIXME: Handle partially overlapping fragments. See
779 // https://reviews.llvm.org/D70121#1849741.
780 DebugVariable ID(Var, Fragment, DL->getInlinedAt());
781 UserValue *&UV = userVarMap[ID];
782 if (!UV) {
783 userValues.push_back(
784 std::make_unique<UserValue>(Var, Fragment, DL, allocator));
785 UV = userValues.back().get();
786 }
787 return UV;
788}
789
790void LDVImpl::mapVirtReg(Register VirtReg, UserValue *EC) {
791 assert(Register::isVirtualRegister(VirtReg) && "Only map VirtRegs")(static_cast <bool> (Register::isVirtualRegister(VirtReg
) && "Only map VirtRegs") ? void (0) : __assert_fail (
"Register::isVirtualRegister(VirtReg) && \"Only map VirtRegs\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 791, __extension__
__PRETTY_FUNCTION__))
;
792 UserValue *&Leader = virtRegToEqClass[VirtReg];
793 Leader = UserValue::merge(Leader, EC);
794}
795
796UserValue *LDVImpl::lookupVirtReg(Register VirtReg) {
797 if (UserValue *UV = virtRegToEqClass.lookup(VirtReg))
798 return UV->getLeader();
799 return nullptr;
800}
801
802bool LDVImpl::handleDebugValue(MachineInstr &MI, SlotIndex Idx) {
803 // DBG_VALUE loc, offset, variable, expr
804 // DBG_VALUE_LIST variable, expr, locs...
805 if (!MI.isDebugValue()) {
806 LLVM_DEBUG(dbgs() << "Can't handle non-DBG_VALUE*: " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Can't handle non-DBG_VALUE*: "
<< MI; } } while (false)
;
807 return false;
808 }
809 if (!MI.getDebugVariableOp().isMetadata()) {
810 LLVM_DEBUG(dbgs() << "Can't handle DBG_VALUE* with invalid variable: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Can't handle DBG_VALUE* with invalid variable: "
<< MI; } } while (false)
811 << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Can't handle DBG_VALUE* with invalid variable: "
<< MI; } } while (false)
;
812 return false;
813 }
814 if (MI.isNonListDebugValue() &&
815 (MI.getNumOperands() != 4 ||
816 !(MI.getDebugOffset().isImm() || MI.getDebugOffset().isReg()))) {
817 LLVM_DEBUG(dbgs() << "Can't handle malformed DBG_VALUE: " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Can't handle malformed DBG_VALUE: "
<< MI; } } while (false)
;
818 return false;
819 }
820
821 // Detect invalid DBG_VALUE instructions, with a debug-use of a virtual
822 // register that hasn't been defined yet. If we do not remove those here, then
823 // the re-insertion of the DBG_VALUE instruction after register allocation
824 // will be incorrect.
825 bool Discard = false;
826 for (const MachineOperand &Op : MI.debug_operands()) {
827 if (Op.isReg() && Register::isVirtualRegister(Op.getReg())) {
828 const Register Reg = Op.getReg();
829 if (!LIS->hasInterval(Reg)) {
830 // The DBG_VALUE is described by a virtual register that does not have a
831 // live interval. Discard the DBG_VALUE.
832 Discard = true;
833 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)
834 << " " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (no LIS interval): "
<< Idx << " " << MI; } } while (false)
;
835 } else {
836 // The DBG_VALUE is only valid if either Reg is live out from Idx, or
837 // Reg is defined dead at Idx (where Idx is the slot index for the
838 // instruction preceding the DBG_VALUE).
839 const LiveInterval &LI = LIS->getInterval(Reg);
840 LiveQueryResult LRQ = LI.Query(Idx);
841 if (!LRQ.valueOutOrDead()) {
842 // We have found a DBG_VALUE with the value in a virtual register that
843 // is not live. Discard the DBG_VALUE.
844 Discard = true;
845 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)
846 << " " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Discarding debug info (reg not live): "
<< Idx << " " << MI; } } while (false)
;
847 }
848 }
849 }
850 }
851
852 // Get or create the UserValue for (variable,offset) here.
853 bool IsIndirect = MI.isDebugOffsetImm();
854 if (IsIndirect)
855 assert(MI.getDebugOffset().getImm() == 0 &&(static_cast <bool> (MI.getDebugOffset().getImm() == 0 &&
"DBG_VALUE with nonzero offset") ? void (0) : __assert_fail (
"MI.getDebugOffset().getImm() == 0 && \"DBG_VALUE with nonzero offset\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 856, __extension__
__PRETTY_FUNCTION__))
856 "DBG_VALUE with nonzero offset")(static_cast <bool> (MI.getDebugOffset().getImm() == 0 &&
"DBG_VALUE with nonzero offset") ? void (0) : __assert_fail (
"MI.getDebugOffset().getImm() == 0 && \"DBG_VALUE with nonzero offset\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 856, __extension__
__PRETTY_FUNCTION__))
;
857 bool IsList = MI.isDebugValueList();
858 const DILocalVariable *Var = MI.getDebugVariable();
859 const DIExpression *Expr = MI.getDebugExpression();
860 UserValue *UV = getUserValue(Var, Expr->getFragmentInfo(), MI.getDebugLoc());
861 if (!Discard)
862 UV->addDef(Idx,
863 ArrayRef<MachineOperand>(MI.debug_operands().begin(),
864 MI.debug_operands().end()),
865 IsIndirect, IsList, *Expr);
866 else {
867 MachineOperand MO = MachineOperand::CreateReg(0U, false);
868 MO.setIsDebug();
869 // We should still pass a list the same size as MI.debug_operands() even if
870 // all MOs are undef, so that DbgVariableValue can correctly adjust the
871 // expression while removing the duplicated undefs.
872 SmallVector<MachineOperand, 4> UndefMOs(MI.getNumDebugOperands(), MO);
873 UV->addDef(Idx, UndefMOs, false, IsList, *Expr);
874 }
875 return true;
876}
877
878MachineBasicBlock::iterator LDVImpl::handleDebugInstr(MachineInstr &MI,
879 SlotIndex Idx) {
880 assert(MI.isDebugValue() || MI.isDebugRef() || MI.isDebugPHI())(static_cast <bool> (MI.isDebugValue() || MI.isDebugRef
() || MI.isDebugPHI()) ? void (0) : __assert_fail ("MI.isDebugValue() || MI.isDebugRef() || MI.isDebugPHI()"
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 880, __extension__
__PRETTY_FUNCTION__))
;
881
882 // In instruction referencing mode, there should be no DBG_VALUE instructions
883 // that refer to virtual registers. They might still refer to constants.
884 if (MI.isDebugValue())
885 assert(!MI.getOperand(0).isReg() || !MI.getOperand(0).getReg().isVirtual())(static_cast <bool> (!MI.getOperand(0).isReg() || !MI.getOperand
(0).getReg().isVirtual()) ? void (0) : __assert_fail ("!MI.getOperand(0).isReg() || !MI.getOperand(0).getReg().isVirtual()"
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 885, __extension__
__PRETTY_FUNCTION__))
;
886
887 // Unlink the instruction, store it in the debug instructions collection.
888 auto NextInst = std::next(MI.getIterator());
889 auto *MBB = MI.getParent();
890 MI.removeFromParent();
891 StashedDebugInstrs.push_back({&MI, Idx, MBB});
892 return NextInst;
893}
894
895bool LDVImpl::handleDebugLabel(MachineInstr &MI, SlotIndex Idx) {
896 // DBG_LABEL label
897 if (MI.getNumOperands() != 1 || !MI.getOperand(0).isMetadata()) {
898 LLVM_DEBUG(dbgs() << "Can't handle " << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Can't handle " <<
MI; } } while (false)
;
899 return false;
900 }
901
902 // Get or create the UserLabel for label here.
903 const DILabel *Label = MI.getDebugLabel();
904 const DebugLoc &DL = MI.getDebugLoc();
905 bool Found = false;
906 for (auto const &L : userLabels) {
907 if (L->matches(Label, DL->getInlinedAt(), Idx)) {
908 Found = true;
909 break;
910 }
911 }
912 if (!Found)
913 userLabels.push_back(std::make_unique<UserLabel>(Label, DL, Idx));
914
915 return true;
916}
917
918bool LDVImpl::collectDebugValues(MachineFunction &mf, bool InstrRef) {
919 bool Changed = false;
920 for (MachineBasicBlock &MBB : mf) {
921 for (MachineBasicBlock::iterator MBBI = MBB.begin(), MBBE = MBB.end();
922 MBBI != MBBE;) {
923 // Use the first debug instruction in the sequence to get a SlotIndex
924 // for following consecutive debug instructions.
925 if (!MBBI->isDebugOrPseudoInstr()) {
926 ++MBBI;
927 continue;
928 }
929 // Debug instructions has no slot index. Use the previous
930 // non-debug instruction's SlotIndex as its SlotIndex.
931 SlotIndex Idx =
932 MBBI == MBB.begin()
933 ? LIS->getMBBStartIdx(&MBB)
934 : LIS->getInstructionIndex(*std::prev(MBBI)).getRegSlot();
935 // Handle consecutive debug instructions with the same slot index.
936 do {
937 // In instruction referencing mode, pass each instr to handleDebugInstr
938 // to be unlinked. Ignore DBG_VALUE_LISTs -- they refer to vregs, and
939 // need to go through the normal live interval splitting process.
940 if (InstrRef && (MBBI->isNonListDebugValue() || MBBI->isDebugPHI() ||
941 MBBI->isDebugRef())) {
942 MBBI = handleDebugInstr(*MBBI, Idx);
943 Changed = true;
944 // In normal debug mode, use the dedicated DBG_VALUE / DBG_LABEL handler
945 // to track things through register allocation, and erase the instr.
946 } else if ((MBBI->isDebugValue() && handleDebugValue(*MBBI, Idx)) ||
947 (MBBI->isDebugLabel() && handleDebugLabel(*MBBI, Idx))) {
948 MBBI = MBB.erase(MBBI);
949 Changed = true;
950 } else
951 ++MBBI;
952 } while (MBBI != MBBE && MBBI->isDebugOrPseudoInstr());
953 }
954 }
955 return Changed;
956}
957
958void UserValue::extendDef(
959 SlotIndex Idx, DbgVariableValue DbgValue,
960 SmallDenseMap<unsigned, std::pair<LiveRange *, const VNInfo *>>
961 &LiveIntervalInfo,
962 Optional<std::pair<SlotIndex, SmallVector<unsigned>>> &Kills,
963 LiveIntervals &LIS) {
964 SlotIndex Start = Idx;
965 MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
966 SlotIndex Stop = LIS.getMBBEndIdx(MBB);
967 LocMap::iterator I = locInts.find(Start);
968
969 // Limit to the intersection of the VNIs' live ranges.
970 for (auto &LII : LiveIntervalInfo) {
971 LiveRange *LR = LII.second.first;
972 assert(LR && LII.second.second && "Missing range info for Idx.")(static_cast <bool> (LR && LII.second.second &&
"Missing range info for Idx.") ? void (0) : __assert_fail ("LR && LII.second.second && \"Missing range info for Idx.\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 972, __extension__
__PRETTY_FUNCTION__))
;
973 LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
974 assert(Segment && Segment->valno == LII.second.second &&(static_cast <bool> (Segment && Segment->valno
== LII.second.second && "Invalid VNInfo for Idx given?"
) ? void (0) : __assert_fail ("Segment && Segment->valno == LII.second.second && \"Invalid VNInfo for Idx given?\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 975, __extension__
__PRETTY_FUNCTION__))
975 "Invalid VNInfo for Idx given?")(static_cast <bool> (Segment && Segment->valno
== LII.second.second && "Invalid VNInfo for Idx given?"
) ? void (0) : __assert_fail ("Segment && Segment->valno == LII.second.second && \"Invalid VNInfo for Idx given?\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 975, __extension__
__PRETTY_FUNCTION__))
;
976 if (Segment->end < Stop) {
977 Stop = Segment->end;
978 Kills = {Stop, {LII.first}};
979 } else if (Segment->end == Stop && Kills.hasValue()) {
980 // If multiple locations end at the same place, track all of them in
981 // Kills.
982 Kills->second.push_back(LII.first);
983 }
984 }
985
986 // There could already be a short def at Start.
987 if (I.valid() && I.start() <= Start) {
988 // Stop when meeting a different location or an already extended interval.
989 Start = Start.getNextSlot();
990 if (I.value() != DbgValue || I.stop() != Start) {
991 // Clear `Kills`, as we have a new def available.
992 Kills = None;
993 return;
994 }
995 // This is a one-slot placeholder. Just skip it.
996 ++I;
997 }
998
999 // Limited by the next def.
1000 if (I.valid() && I.start() < Stop) {
1001 Stop = I.start();
1002 // Clear `Kills`, as we have a new def available.
1003 Kills = None;
1004 }
1005
1006 if (Start < Stop) {
1007 DbgVariableValue ExtDbgValue(DbgValue);
1008 I.insert(Start, Stop, std::move(ExtDbgValue));
1009 }
1010}
1011
1012void UserValue::addDefsFromCopies(
1013 DbgVariableValue DbgValue,
1014 SmallVectorImpl<std::pair<unsigned, LiveInterval *>> &LocIntervals,
1015 SlotIndex KilledAt,
1016 SmallVectorImpl<std::pair<SlotIndex, DbgVariableValue>> &NewDefs,
1017 MachineRegisterInfo &MRI, LiveIntervals &LIS) {
1018 // Don't track copies from physregs, there are too many uses.
1019 if (any_of(LocIntervals, [](auto LocI) {
1020 return !Register::isVirtualRegister(LocI.second->reg());
1021 }))
1022 return;
1023
1024 // Collect all the (vreg, valno) pairs that are copies of LI.
1025 SmallDenseMap<unsigned,
1026 SmallVector<std::pair<LiveInterval *, const VNInfo *>, 4>>
1027 CopyValues;
1028 for (auto &LocInterval : LocIntervals) {
1029 unsigned LocNo = LocInterval.first;
1030 LiveInterval *LI = LocInterval.second;
1031 for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg())) {
1032 MachineInstr *MI = MO.getParent();
1033 // Copies of the full value.
1034 if (MO.getSubReg() || !MI->isCopy())
1035 continue;
1036 Register DstReg = MI->getOperand(0).getReg();
1037
1038 // Don't follow copies to physregs. These are usually setting up call
1039 // arguments, and the argument registers are always call clobbered. We are
1040 // better off in the source register which could be a callee-saved
1041 // register, or it could be spilled.
1042 if (!Register::isVirtualRegister(DstReg))
1043 continue;
1044
1045 // Is the value extended to reach this copy? If not, another def may be
1046 // blocking it, or we are looking at a wrong value of LI.
1047 SlotIndex Idx = LIS.getInstructionIndex(*MI);
1048 LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
1049 if (!I.valid() || I.value() != DbgValue)
1050 continue;
1051
1052 if (!LIS.hasInterval(DstReg))
1053 continue;
1054 LiveInterval *DstLI = &LIS.getInterval(DstReg);
1055 const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
1056 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\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 1056, __extension__
__PRETTY_FUNCTION__))
;
1057 CopyValues[LocNo].push_back(std::make_pair(DstLI, DstVNI));
1058 }
1059 }
1060
1061 if (CopyValues.empty())
1062 return;
1063
1064#if !defined(NDEBUG)
1065 for (auto &LocInterval : LocIntervals)
1066 LLVM_DEBUG(dbgs() << "Got " << CopyValues[LocInterval.first].size()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Got " << CopyValues
[LocInterval.first].size() << " copies of " << *LocInterval
.second << '\n'; } } while (false)
1067 << " copies of " << *LocInterval.second << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Got " << CopyValues
[LocInterval.first].size() << " copies of " << *LocInterval
.second << '\n'; } } while (false)
;
1068#endif
1069
1070 // Try to add defs of the copied values for the kill point. Check that there
1071 // isn't already a def at Idx.
1072 LocMap::iterator I = locInts.find(KilledAt);
1073 if (I.valid() && I.start() <= KilledAt)
1074 return;
1075 DbgVariableValue NewValue(DbgValue);
1076 for (auto &LocInterval : LocIntervals) {
1077 unsigned LocNo = LocInterval.first;
1078 bool FoundCopy = false;
1079 for (auto &LIAndVNI : CopyValues[LocNo]) {
1080 LiveInterval *DstLI = LIAndVNI.first;
1081 const VNInfo *DstVNI = LIAndVNI.second;
1082 if (DstLI->getVNInfoAt(KilledAt) != DstVNI)
1083 continue;
1084 LLVM_DEBUG(dbgs() << "Kill at " << KilledAt << " covered by valno #"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Kill at " << KilledAt
<< " covered by valno #" << DstVNI->id <<
" in " << *DstLI << '\n'; } } while (false)
1085 << DstVNI->id << " in " << *DstLI << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "Kill at " << KilledAt
<< " covered by valno #" << DstVNI->id <<
" in " << *DstLI << '\n'; } } while (false)
;
1086 MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
1087 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\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 1087, __extension__
__PRETTY_FUNCTION__))
;
1088 unsigned NewLocNo = getLocationNo(CopyMI->getOperand(0));
1089 NewValue = NewValue.changeLocNo(LocNo, NewLocNo);
1090 FoundCopy = true;
1091 break;
1092 }
1093 // If there are any killed locations we can't find a copy for, we can't
1094 // extend the variable value.
1095 if (!FoundCopy)
1096 return;
1097 }
1098 I.insert(KilledAt, KilledAt.getNextSlot(), NewValue);
1099 NewDefs.push_back(std::make_pair(KilledAt, NewValue));
1100}
1101
1102void UserValue::computeIntervals(MachineRegisterInfo &MRI,
1103 const TargetRegisterInfo &TRI,
1104 LiveIntervals &LIS, LexicalScopes &LS) {
1105 SmallVector<std::pair<SlotIndex, DbgVariableValue>, 16> Defs;
1106
1107 // Collect all defs to be extended (Skipping undefs).
1108 for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
1109 if (!I.value().isUndef())
1110 Defs.push_back(std::make_pair(I.start(), I.value()));
1111
1112 // Extend all defs, and possibly add new ones along the way.
1113 for (unsigned i = 0; i != Defs.size(); ++i) {
1114 SlotIndex Idx = Defs[i].first;
1115 DbgVariableValue DbgValue = Defs[i].second;
1116 SmallDenseMap<unsigned, std::pair<LiveRange *, const VNInfo *>> LIs;
1117 SmallVector<const VNInfo *, 4> VNIs;
1118 bool ShouldExtendDef = false;
1119 for (unsigned LocNo : DbgValue.loc_nos()) {
1120 const MachineOperand &LocMO = locations[LocNo];
1121 if (!LocMO.isReg() || !Register::isVirtualRegister(LocMO.getReg())) {
1122 ShouldExtendDef |= !LocMO.isReg();
1123 continue;
1124 }
1125 ShouldExtendDef = true;
1126 LiveInterval *LI = nullptr;
1127 const VNInfo *VNI = nullptr;
1128 if (LIS.hasInterval(LocMO.getReg())) {
1129 LI = &LIS.getInterval(LocMO.getReg());
1130 VNI = LI->getVNInfoAt(Idx);
1131 }
1132 if (LI && VNI)
1133 LIs[LocNo] = {LI, VNI};
1134 }
1135 if (ShouldExtendDef) {
1136 Optional<std::pair<SlotIndex, SmallVector<unsigned>>> Kills;
1137 extendDef(Idx, DbgValue, LIs, Kills, LIS);
1138
1139 if (Kills) {
1140 SmallVector<std::pair<unsigned, LiveInterval *>, 2> KilledLocIntervals;
1141 bool AnySubreg = false;
1142 for (unsigned LocNo : Kills->second) {
1143 const MachineOperand &LocMO = this->locations[LocNo];
1144 if (LocMO.getSubReg()) {
1145 AnySubreg = true;
1146 break;
1147 }
1148 LiveInterval *LI = &LIS.getInterval(LocMO.getReg());
1149 KilledLocIntervals.push_back({LocNo, LI});
1150 }
1151
1152 // FIXME: Handle sub-registers in addDefsFromCopies. The problem is that
1153 // if the original location for example is %vreg0:sub_hi, and we find a
1154 // full register copy in addDefsFromCopies (at the moment it only
1155 // handles full register copies), then we must add the sub1 sub-register
1156 // index to the new location. However, that is only possible if the new
1157 // virtual register is of the same regclass (or if there is an
1158 // equivalent sub-register in that regclass). For now, simply skip
1159 // handling copies if a sub-register is involved.
1160 if (!AnySubreg)
1161 addDefsFromCopies(DbgValue, KilledLocIntervals, Kills->first, Defs,
1162 MRI, LIS);
1163 }
1164 }
1165
1166 // For physregs, we only mark the start slot idx. DwarfDebug will see it
1167 // as if the DBG_VALUE is valid up until the end of the basic block, or
1168 // the next def of the physical register. So we do not need to extend the
1169 // range. It might actually happen that the DBG_VALUE is the last use of
1170 // the physical register (e.g. if this is an unused input argument to a
1171 // function).
1172 }
1173
1174 // The computed intervals may extend beyond the range of the debug
1175 // location's lexical scope. In this case, splitting of an interval
1176 // can result in an interval outside of the scope being created,
1177 // causing extra unnecessary DBG_VALUEs to be emitted. To prevent
1178 // this, trim the intervals to the lexical scope in the case of inlined
1179 // variables, since heavy inlining may cause production of dramatically big
1180 // number of DBG_VALUEs to be generated.
1181 if (!dl.getInlinedAt())
1182 return;
1183
1184 LexicalScope *Scope = LS.findLexicalScope(dl);
1185 if (!Scope)
1186 return;
1187
1188 SlotIndex PrevEnd;
1189 LocMap::iterator I = locInts.begin();
1190
1191 // Iterate over the lexical scope ranges. Each time round the loop
1192 // we check the intervals for overlap with the end of the previous
1193 // range and the start of the next. The first range is handled as
1194 // a special case where there is no PrevEnd.
1195 for (const InsnRange &Range : Scope->getRanges()) {
1196 SlotIndex RStart = LIS.getInstructionIndex(*Range.first);
1197 SlotIndex REnd = LIS.getInstructionIndex(*Range.second);
1198
1199 // Variable locations at the first instruction of a block should be
1200 // based on the block's SlotIndex, not the first instruction's index.
1201 if (Range.first == Range.first->getParent()->begin())
1202 RStart = LIS.getSlotIndexes()->getIndexBefore(*Range.first);
1203
1204 // At the start of each iteration I has been advanced so that
1205 // I.stop() >= PrevEnd. Check for overlap.
1206 if (PrevEnd && I.start() < PrevEnd) {
1207 SlotIndex IStop = I.stop();
1208 DbgVariableValue DbgValue = I.value();
1209
1210 // Stop overlaps previous end - trim the end of the interval to
1211 // the scope range.
1212 I.setStopUnchecked(PrevEnd);
1213 ++I;
1214
1215 // If the interval also overlaps the start of the "next" (i.e.
1216 // current) range create a new interval for the remainder (which
1217 // may be further trimmed).
1218 if (RStart < IStop)
1219 I.insert(RStart, IStop, DbgValue);
1220 }
1221
1222 // Advance I so that I.stop() >= RStart, and check for overlap.
1223 I.advanceTo(RStart);
1224 if (!I.valid())
1225 return;
1226
1227 if (I.start() < RStart) {
1228 // Interval start overlaps range - trim to the scope range.
1229 I.setStartUnchecked(RStart);
1230 // Remember that this interval was trimmed.
1231 trimmedDefs.insert(RStart);
1232 }
1233
1234 // The end of a lexical scope range is the last instruction in the
1235 // range. To convert to an interval we need the index of the
1236 // instruction after it.
1237 REnd = REnd.getNextIndex();
1238
1239 // Advance I to first interval outside current range.
1240 I.advanceTo(REnd);
1241 if (!I.valid())
1242 return;
1243
1244 PrevEnd = REnd;
1245 }
1246
1247 // Check for overlap with end of final range.
1248 if (PrevEnd && I.start() < PrevEnd)
1249 I.setStopUnchecked(PrevEnd);
1250}
1251
1252void LDVImpl::computeIntervals() {
1253 LexicalScopes LS;
1254 LS.initialize(*MF);
1255
1256 for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
1257 userValues[i]->computeIntervals(MF->getRegInfo(), *TRI, *LIS, LS);
1258 userValues[i]->mapVirtRegs(this);
1259 }
1260}
1261
1262bool LDVImpl::runOnMachineFunction(MachineFunction &mf, bool InstrRef) {
1263 clear();
1264 MF = &mf;
1265 LIS = &pass.getAnalysis<LiveIntervals>();
1266 TRI = mf.getSubtarget().getRegisterInfo();
1267 LLVM_DEBUG(dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
<< mf.getName() << " **********\n"; } } while (false
)
1268 << mf.getName() << " **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** COMPUTING LIVE DEBUG VARIABLES: "
<< mf.getName() << " **********\n"; } } while (false
)
;
1269
1270 bool Changed = collectDebugValues(mf, InstrRef);
1271 computeIntervals();
1272 LLVM_DEBUG(print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { print(dbgs()); } } while (false)
;
1273
1274 // Collect the set of VReg / SlotIndexs where PHIs occur; index the sensitive
1275 // VRegs too, for when we're notified of a range split.
1276 SlotIndexes *Slots = LIS->getSlotIndexes();
1277 for (const auto &PHIIt : MF->DebugPHIPositions) {
1278 const MachineFunction::DebugPHIRegallocPos &Position = PHIIt.second;
1279 MachineBasicBlock *MBB = Position.MBB;
1280 Register Reg = Position.Reg;
1281 unsigned SubReg = Position.SubReg;
1282 SlotIndex SI = Slots->getMBBStartIdx(MBB);
1283 PHIValPos VP = {SI, Reg, SubReg};
1284 PHIValToPos.insert(std::make_pair(PHIIt.first, VP));
1285 RegToPHIIdx[Reg].push_back(PHIIt.first);
1286 }
1287
1288 ModifiedMF = Changed;
1289 return Changed;
1290}
1291
1292static void removeDebugInstrs(MachineFunction &mf) {
1293 for (MachineBasicBlock &MBB : mf) {
1294 for (MachineInstr &MI : llvm::make_early_inc_range(MBB))
1295 if (MI.isDebugInstr())
1296 MBB.erase(&MI);
1297 }
1298}
1299
1300bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
1301 if (!EnableLDV)
1302 return false;
1303 if (!mf.getFunction().getSubprogram()) {
1304 removeDebugInstrs(mf);
1305 return false;
1306 }
1307
1308 // Have we been asked to track variable locations using instruction
1309 // referencing?
1310 bool InstrRef = mf.useDebugInstrRef();
1311
1312 if (!pImpl)
1313 pImpl = new LDVImpl(this);
1314 return static_cast<LDVImpl *>(pImpl)->runOnMachineFunction(mf, InstrRef);
1315}
1316
1317void LiveDebugVariables::releaseMemory() {
1318 if (pImpl)
1319 static_cast<LDVImpl*>(pImpl)->clear();
1320}
1321
1322LiveDebugVariables::~LiveDebugVariables() {
1323 if (pImpl)
1324 delete static_cast<LDVImpl*>(pImpl);
1325}
1326
1327//===----------------------------------------------------------------------===//
1328// Live Range Splitting
1329//===----------------------------------------------------------------------===//
1330
1331bool
1332UserValue::splitLocation(unsigned OldLocNo, ArrayRef<Register> NewRegs,
1333 LiveIntervals& LIS) {
1334 LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
1335 dbgs() << "Splitting Loc" << OldLocNo << '\t';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
1336 print(dbgs(), nullptr);do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
1337 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Splitting Loc" <<
OldLocNo << '\t'; print(dbgs(), nullptr); }; } } while
(false)
;
1338 bool DidChange = false;
1339 LocMap::iterator LocMapI;
1340 LocMapI.setMap(locInts);
1341 for (Register NewReg : NewRegs) {
1342 LiveInterval *LI = &LIS.getInterval(NewReg);
1343 if (LI->empty())
1344 continue;
1345
1346 // Don't allocate the new LocNo until it is needed.
1347 unsigned NewLocNo = UndefLocNo;
1348
1349 // Iterate over the overlaps between locInts and LI.
1350 LocMapI.find(LI->beginIndex());
1351 if (!LocMapI.valid())
1352 continue;
1353 LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
1354 LiveInterval::iterator LIE = LI->end();
1355 while (LocMapI.valid() && LII != LIE) {
1356 // At this point, we know that LocMapI.stop() > LII->start.
1357 LII = LI->advanceTo(LII, LocMapI.start());
1358 if (LII == LIE)
1359 break;
1360
1361 // Now LII->end > LocMapI.start(). Do we have an overlap?
1362 if (LocMapI.value().containsLocNo(OldLocNo) &&
1363 LII->start < LocMapI.stop()) {
1364 // Overlapping correct location. Allocate NewLocNo now.
1365 if (NewLocNo == UndefLocNo) {
1366 MachineOperand MO = MachineOperand::CreateReg(LI->reg(), false);
1367 MO.setSubReg(locations[OldLocNo].getSubReg());
1368 NewLocNo = getLocationNo(MO);
1369 DidChange = true;
1370 }
1371
1372 SlotIndex LStart = LocMapI.start();
1373 SlotIndex LStop = LocMapI.stop();
1374 DbgVariableValue OldDbgValue = LocMapI.value();
1375
1376 // Trim LocMapI down to the LII overlap.
1377 if (LStart < LII->start)
1378 LocMapI.setStartUnchecked(LII->start);
1379 if (LStop > LII->end)
1380 LocMapI.setStopUnchecked(LII->end);
1381
1382 // Change the value in the overlap. This may trigger coalescing.
1383 LocMapI.setValue(OldDbgValue.changeLocNo(OldLocNo, NewLocNo));
1384
1385 // Re-insert any removed OldDbgValue ranges.
1386 if (LStart < LocMapI.start()) {
1387 LocMapI.insert(LStart, LocMapI.start(), OldDbgValue);
1388 ++LocMapI;
1389 assert(LocMapI.valid() && "Unexpected coalescing")(static_cast <bool> (LocMapI.valid() && "Unexpected coalescing"
) ? void (0) : __assert_fail ("LocMapI.valid() && \"Unexpected coalescing\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 1389, __extension__
__PRETTY_FUNCTION__))
;
1390 }
1391 if (LStop > LocMapI.stop()) {
1392 ++LocMapI;
1393 LocMapI.insert(LII->end, LStop, OldDbgValue);
1394 --LocMapI;
1395 }
1396 }
1397
1398 // Advance to the next overlap.
1399 if (LII->end < LocMapI.stop()) {
1400 if (++LII == LIE)
1401 break;
1402 LocMapI.advanceTo(LII->start);
1403 } else {
1404 ++LocMapI;
1405 if (!LocMapI.valid())
1406 break;
1407 LII = LI->advanceTo(LII, LocMapI.start());
1408 }
1409 }
1410 }
1411
1412 // Finally, remove OldLocNo unless it is still used by some interval in the
1413 // locInts map. One case when OldLocNo still is in use is when the register
1414 // has been spilled. In such situations the spilled register is kept as a
1415 // location until rewriteLocations is called (VirtRegMap is mapping the old
1416 // register to the spill slot). So for a while we can have locations that map
1417 // to virtual registers that have been removed from both the MachineFunction
1418 // and from LiveIntervals.
1419 //
1420 // We may also just be using the location for a value with a different
1421 // expression.
1422 removeLocationIfUnused(OldLocNo);
1423
1424 LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1425 dbgs() << "Split result: \t";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1426 print(dbgs(), nullptr);do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
1427 })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { { dbgs() << "Split result: \t"; print
(dbgs(), nullptr); }; } } while (false)
;
1428 return DidChange;
1429}
1430
1431bool
1432UserValue::splitRegister(Register OldReg, ArrayRef<Register> NewRegs,
1433 LiveIntervals &LIS) {
1434 bool DidChange = false;
1435 // Split locations referring to OldReg. Iterate backwards so splitLocation can
1436 // safely erase unused locations.
1437 for (unsigned i = locations.size(); i ; --i) {
1438 unsigned LocNo = i-1;
1439 const MachineOperand *Loc = &locations[LocNo];
1440 if (!Loc->isReg() || Loc->getReg() != OldReg)
1441 continue;
1442 DidChange |= splitLocation(LocNo, NewRegs, LIS);
1443 }
1444 return DidChange;
1445}
1446
1447void LDVImpl::splitPHIRegister(Register OldReg, ArrayRef<Register> NewRegs) {
1448 auto RegIt = RegToPHIIdx.find(OldReg);
1449 if (RegIt == RegToPHIIdx.end())
1450 return;
1451
1452 std::vector<std::pair<Register, unsigned>> NewRegIdxes;
1453 // Iterate over all the debug instruction numbers affected by this split.
1454 for (unsigned InstrID : RegIt->second) {
1455 auto PHIIt = PHIValToPos.find(InstrID);
1456 assert(PHIIt != PHIValToPos.end())(static_cast <bool> (PHIIt != PHIValToPos.end()) ? void
(0) : __assert_fail ("PHIIt != PHIValToPos.end()", "llvm/lib/CodeGen/LiveDebugVariables.cpp"
, 1456, __extension__ __PRETTY_FUNCTION__))
;
1457 const SlotIndex &Slot = PHIIt->second.SI;
1458 assert(OldReg == PHIIt->second.Reg)(static_cast <bool> (OldReg == PHIIt->second.Reg) ? void
(0) : __assert_fail ("OldReg == PHIIt->second.Reg", "llvm/lib/CodeGen/LiveDebugVariables.cpp"
, 1458, __extension__ __PRETTY_FUNCTION__))
;
1459
1460 // Find the new register that covers this position.
1461 for (auto NewReg : NewRegs) {
1462 const LiveInterval &LI = LIS->getInterval(NewReg);
1463 auto LII = LI.find(Slot);
1464 if (LII != LI.end() && LII->start <= Slot) {
1465 // This new register covers this PHI position, record this for indexing.
1466 NewRegIdxes.push_back(std::make_pair(NewReg, InstrID));
1467 // Record that this value lives in a different VReg now.
1468 PHIIt->second.Reg = NewReg;
1469 break;
1470 }
1471 }
1472
1473 // If we do not find a new register covering this PHI, then register
1474 // allocation has dropped its location, for example because it's not live.
1475 // The old VReg will not be mapped to a physreg, and the instruction
1476 // number will have been optimized out.
1477 }
1478
1479 // Re-create register index using the new register numbers.
1480 RegToPHIIdx.erase(RegIt);
1481 for (auto &RegAndInstr : NewRegIdxes)
1482 RegToPHIIdx[RegAndInstr.first].push_back(RegAndInstr.second);
1483}
1484
1485void LDVImpl::splitRegister(Register OldReg, ArrayRef<Register> NewRegs) {
1486 // Consider whether this split range affects any PHI locations.
1487 splitPHIRegister(OldReg, NewRegs);
1488
1489 // Check whether any intervals mapped by a DBG_VALUE were split and need
1490 // updating.
1491 bool DidChange = false;
1492 for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
1493 DidChange |= UV->splitRegister(OldReg, NewRegs, *LIS);
1494
1495 if (!DidChange)
1496 return;
1497
1498 // Map all of the new virtual registers.
1499 UserValue *UV = lookupVirtReg(OldReg);
1500 for (Register NewReg : NewRegs)
1501 mapVirtReg(NewReg, UV);
1502}
1503
1504void LiveDebugVariables::
1505splitRegister(Register OldReg, ArrayRef<Register> NewRegs, LiveIntervals &LIS) {
1506 if (pImpl)
1507 static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
1508}
1509
1510void UserValue::rewriteLocations(VirtRegMap &VRM, const MachineFunction &MF,
1511 const TargetInstrInfo &TII,
1512 const TargetRegisterInfo &TRI,
1513 SpillOffsetMap &SpillOffsets) {
1514 // Build a set of new locations with new numbers so we can coalesce our
1515 // IntervalMap if two vreg intervals collapse to the same physical location.
1516 // Use MapVector instead of SetVector because MapVector::insert returns the
1517 // position of the previously or newly inserted element. The boolean value
1518 // tracks if the location was produced by a spill.
1519 // FIXME: This will be problematic if we ever support direct and indirect
1520 // frame index locations, i.e. expressing both variables in memory and
1521 // 'int x, *px = &x'. The "spilled" bit must become part of the location.
1522 MapVector<MachineOperand, std::pair<bool, unsigned>> NewLocations;
1523 SmallVector<unsigned, 4> LocNoMap(locations.size());
1524 for (unsigned I = 0, E = locations.size(); I != E; ++I) {
1525 bool Spilled = false;
1526 unsigned SpillOffset = 0;
1527 MachineOperand Loc = locations[I];
1528 // Only virtual registers are rewritten.
1529 if (Loc.isReg() && Loc.getReg() &&
1530 Register::isVirtualRegister(Loc.getReg())) {
1531 Register VirtReg = Loc.getReg();
1532 if (VRM.isAssignedReg(VirtReg) &&
1533 Register::isPhysicalRegister(VRM.getPhys(VirtReg))) {
1534 // This can create a %noreg operand in rare cases when the sub-register
1535 // index is no longer available. That means the user value is in a
1536 // non-existent sub-register, and %noreg is exactly what we want.
1537 Loc.substPhysReg(VRM.getPhys(VirtReg), TRI);
1538 } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
1539 // Retrieve the stack slot offset.
1540 unsigned SpillSize;
1541 const MachineRegisterInfo &MRI = MF.getRegInfo();
1542 const TargetRegisterClass *TRC = MRI.getRegClass(VirtReg);
1543 bool Success = TII.getStackSlotRange(TRC, Loc.getSubReg(), SpillSize,
1544 SpillOffset, MF);
1545
1546 // FIXME: Invalidate the location if the offset couldn't be calculated.
1547 (void)Success;
1548
1549 Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
1550 Spilled = true;
1551 } else {
1552 Loc.setReg(0);
1553 Loc.setSubReg(0);
1554 }
1555 }
1556
1557 // Insert this location if it doesn't already exist and record a mapping
1558 // from the old number to the new number.
1559 auto InsertResult = NewLocations.insert({Loc, {Spilled, SpillOffset}});
1560 unsigned NewLocNo = std::distance(NewLocations.begin(), InsertResult.first);
1561 LocNoMap[I] = NewLocNo;
1562 }
1563
1564 // Rewrite the locations and record the stack slot offsets for spills.
1565 locations.clear();
1566 SpillOffsets.clear();
1567 for (auto &Pair : NewLocations) {
1568 bool Spilled;
1569 unsigned SpillOffset;
1570 std::tie(Spilled, SpillOffset) = Pair.second;
1571 locations.push_back(Pair.first);
1572 if (Spilled) {
1573 unsigned NewLocNo = std::distance(&*NewLocations.begin(), &Pair);
1574 SpillOffsets[NewLocNo] = SpillOffset;
1575 }
1576 }
1577
1578 // Update the interval map, but only coalesce left, since intervals to the
1579 // right use the old location numbers. This should merge two contiguous
1580 // DBG_VALUE intervals with different vregs that were allocated to the same
1581 // physical register.
1582 for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
1583 I.setValueUnchecked(I.value().remapLocNos(LocNoMap));
1584 I.setStart(I.start());
1585 }
1586}
1587
1588/// Find an iterator for inserting a DBG_VALUE instruction.
1589static MachineBasicBlock::iterator
1590findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx, LiveIntervals &LIS,
1591 BlockSkipInstsMap &BBSkipInstsMap) {
1592 SlotIndex Start = LIS.getMBBStartIdx(MBB);
1593 Idx = Idx.getBaseIndex();
1594
1595 // Try to find an insert location by going backwards from Idx.
1596 MachineInstr *MI;
1597 while (!(MI = LIS.getInstructionFromIndex(Idx))) {
1598 // We've reached the beginning of MBB.
1599 if (Idx == Start) {
1600 // Retrieve the last PHI/Label/Debug location found when calling
1601 // SkipPHIsLabelsAndDebug last time. Start searching from there.
1602 //
1603 // Note the iterator kept in BBSkipInstsMap is one step back based
1604 // on the iterator returned by SkipPHIsLabelsAndDebug last time.
1605 // One exception is when SkipPHIsLabelsAndDebug returns MBB->begin(),
1606 // BBSkipInstsMap won't save it. This is to consider the case that
1607 // new instructions may be inserted at the beginning of MBB after
1608 // last call of SkipPHIsLabelsAndDebug. If we save MBB->begin() in
1609 // BBSkipInstsMap, after new non-phi/non-label/non-debug instructions
1610 // are inserted at the beginning of the MBB, the iterator in
1611 // BBSkipInstsMap won't point to the beginning of the MBB anymore.
1612 // Therefore The next search in SkipPHIsLabelsAndDebug will skip those
1613 // newly added instructions and that is unwanted.
1614 MachineBasicBlock::iterator BeginIt;
1615 auto MapIt = BBSkipInstsMap.find(MBB);
1616 if (MapIt == BBSkipInstsMap.end())
1617 BeginIt = MBB->begin();
1618 else
1619 BeginIt = std::next(MapIt->second);
1620 auto I = MBB->SkipPHIsLabelsAndDebug(BeginIt);
1621 if (I != BeginIt)
1622 BBSkipInstsMap[MBB] = std::prev(I);
1623 return I;
1624 }
1625 Idx = Idx.getPrevIndex();
1626 }
1627
1628 // Don't insert anything after the first terminator, though.
1629 return MI->isTerminator() ? MBB->getFirstTerminator() :
1630 std::next(MachineBasicBlock::iterator(MI));
1631}
1632
1633/// Find an iterator for inserting the next DBG_VALUE instruction
1634/// (or end if no more insert locations found).
1635static MachineBasicBlock::iterator
1636findNextInsertLocation(MachineBasicBlock *MBB, MachineBasicBlock::iterator I,
1637 SlotIndex StopIdx, ArrayRef<MachineOperand> LocMOs,
1638 LiveIntervals &LIS, const TargetRegisterInfo &TRI) {
1639 SmallVector<Register, 4> Regs;
1640 for (const MachineOperand &LocMO : LocMOs)
1641 if (LocMO.isReg())
1642 Regs.push_back(LocMO.getReg());
1643 if (Regs.empty())
1644 return MBB->instr_end();
1645
1646 // Find the next instruction in the MBB that define the register Reg.
1647 while (I != MBB->end() && !I->isTerminator()) {
1648 if (!LIS.isNotInMIMap(*I) &&
1649 SlotIndex::isEarlierEqualInstr(StopIdx, LIS.getInstructionIndex(*I)))
1650 break;
1651 if (any_of(Regs, [&I, &TRI](Register &Reg) {
1652 return I->definesRegister(Reg, &TRI);
1653 }))
1654 // The insert location is directly after the instruction/bundle.
1655 return std::next(I);
1656 ++I;
1657 }
1658 return MBB->end();
1659}
1660
1661void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
1662 SlotIndex StopIdx, DbgVariableValue DbgValue,
1663 ArrayRef<bool> LocSpills,
1664 ArrayRef<unsigned> SpillOffsets,
1665 LiveIntervals &LIS, const TargetInstrInfo &TII,
1666 const TargetRegisterInfo &TRI,
1667 BlockSkipInstsMap &BBSkipInstsMap) {
1668 SlotIndex MBBEndIdx = LIS.getMBBEndIdx(&*MBB);
1669 // Only search within the current MBB.
1670 StopIdx = (MBBEndIdx < StopIdx) ? MBBEndIdx : StopIdx;
1671 MachineBasicBlock::iterator I =
1672 findInsertLocation(MBB, StartIdx, LIS, BBSkipInstsMap);
1673 // Undef values don't exist in locations so create new "noreg" register MOs
1674 // for them. See getLocationNo().
1675 SmallVector<MachineOperand, 8> MOs;
1676 if (DbgValue.isUndef()) {
1677 MOs.assign(DbgValue.loc_nos().size(),
1678 MachineOperand::CreateReg(
1679 /* Reg */ 0, /* isDef */ false, /* isImp */ false,
1680 /* isKill */ false, /* isDead */ false,
1681 /* isUndef */ false, /* isEarlyClobber */ false,
1682 /* SubReg */ 0, /* isDebug */ true));
1683 } else {
1684 for (unsigned LocNo : DbgValue.loc_nos())
1685 MOs.push_back(locations[LocNo]);
1686 }
1687
1688 ++NumInsertedDebugValues;
1689
1690 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\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 1692, __extension__
__PRETTY_FUNCTION__))
1691 ->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\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 1692, __extension__
__PRETTY_FUNCTION__))
1692 "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\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 1692, __extension__
__PRETTY_FUNCTION__))
;
1693
1694 // If the location was spilled, the new DBG_VALUE will be indirect. If the
1695 // original DBG_VALUE was indirect, we need to add DW_OP_deref to indicate
1696 // that the original virtual register was a pointer. Also, add the stack slot
1697 // offset for the spilled register to the expression.
1698 const DIExpression *Expr = DbgValue.getExpression();
1699 bool IsIndirect = DbgValue.getWasIndirect();
1700 bool IsList = DbgValue.getWasList();
1701 for (unsigned I = 0, E = LocSpills.size(); I != E; ++I) {
1702 if (LocSpills[I]) {
1703 if (!IsList) {
1704 uint8_t DIExprFlags = DIExpression::ApplyOffset;
1705 if (IsIndirect)
1706 DIExprFlags |= DIExpression::DerefAfter;
1707 Expr = DIExpression::prepend(Expr, DIExprFlags, SpillOffsets[I]);
1708 IsIndirect = true;
1709 } else {
1710 SmallVector<uint64_t, 4> Ops;
1711 DIExpression::appendOffset(Ops, SpillOffsets[I]);
1712 Ops.push_back(dwarf::DW_OP_deref);
1713 Expr = DIExpression::appendOpsToArg(Expr, Ops, I);
1714 }
1715 }
1716
1717 assert((!LocSpills[I] || MOs[I].isFI()) &&(static_cast <bool> ((!LocSpills[I] || MOs[I].isFI()) &&
"a spilled location must be a frame index") ? void (0) : __assert_fail
("(!LocSpills[I] || MOs[I].isFI()) && \"a spilled location must be a frame index\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 1718, __extension__
__PRETTY_FUNCTION__))
1718 "a spilled location must be a frame index")(static_cast <bool> ((!LocSpills[I] || MOs[I].isFI()) &&
"a spilled location must be a frame index") ? void (0) : __assert_fail
("(!LocSpills[I] || MOs[I].isFI()) && \"a spilled location must be a frame index\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 1718, __extension__
__PRETTY_FUNCTION__))
;
1719 }
1720
1721 unsigned DbgValueOpcode =
1722 IsList ? TargetOpcode::DBG_VALUE_LIST : TargetOpcode::DBG_VALUE;
1723 do {
1724 BuildMI(*MBB, I, getDebugLoc(), TII.get(DbgValueOpcode), IsIndirect, MOs,
1725 Variable, Expr);
1726
1727 // Continue and insert DBG_VALUES after every redefinition of a register
1728 // associated with the debug value within the range
1729 I = findNextInsertLocation(MBB, I, StopIdx, MOs, LIS, TRI);
1730 } while (I != MBB->end());
1731}
1732
1733void UserLabel::insertDebugLabel(MachineBasicBlock *MBB, SlotIndex Idx,
1734 LiveIntervals &LIS, const TargetInstrInfo &TII,
1735 BlockSkipInstsMap &BBSkipInstsMap) {
1736 MachineBasicBlock::iterator I =
1737 findInsertLocation(MBB, Idx, LIS, BBSkipInstsMap);
1738 ++NumInsertedDebugLabels;
1739 BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_LABEL))
1740 .addMetadata(Label);
1741}
1742
1743void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
1744 const TargetInstrInfo &TII,
1745 const TargetRegisterInfo &TRI,
1746 const SpillOffsetMap &SpillOffsets,
1747 BlockSkipInstsMap &BBSkipInstsMap) {
1748 MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
1749
1750 for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
12
Loop condition is true. Entering loop body
1751 SlotIndex Start = I.start();
1752 SlotIndex Stop = I.stop();
1753 DbgVariableValue DbgValue = I.value();
1754
1755 SmallVector<bool> SpilledLocs;
1756 SmallVector<unsigned> LocSpillOffsets;
1757 for (unsigned LocNo : DbgValue.loc_nos()) {
13
Assuming '__begin2' is equal to '__end2'
1758 auto SpillIt =
1759 !DbgValue.isUndef() ? SpillOffsets.find(LocNo) : SpillOffsets.end();
1760 bool Spilled = SpillIt != SpillOffsets.end();
1761 SpilledLocs.push_back(Spilled);
1762 LocSpillOffsets.push_back(Spilled ? SpillIt->second : 0);
1763 }
1764
1765 // If the interval start was trimmed to the lexical scope insert the
1766 // DBG_VALUE at the previous index (otherwise it appears after the
1767 // first instruction in the range).
1768 if (trimmedDefs.count(Start))
14
Assuming the condition is false
1769 Start = Start.getPrevIndex();
1770
1771 LLVM_DEBUG(auto &dbg = dbgs(); dbg << "\t[" << Start << ';' << Stop << "):";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { auto &dbg = dbgs(); dbg << "\t["
<< Start << ';' << Stop << "):"; DbgValue
.printLocNos(dbg); } } while (false)
15
Taking false branch
16
Assuming 'DebugFlag' is true
17
Assuming the condition is true
18
Taking true branch
19
Calling 'DbgVariableValue::printLocNos'
1772 DbgValue.printLocNos(dbg))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { auto &dbg = dbgs(); dbg << "\t["
<< Start << ';' << Stop << "):"; DbgValue
.printLocNos(dbg); } } while (false)
;
1773 MachineFunction::iterator MBB = LIS.getMBBFromIndex(Start)->getIterator();
1774 SlotIndex MBBEnd = LIS.getMBBEndIdx(&*MBB);
1775
1776 LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB) << '-' << MBBEnd; } } while (false)
;
1777 insertDebugValue(&*MBB, Start, Stop, DbgValue, SpilledLocs, LocSpillOffsets,
1778 LIS, TII, TRI, BBSkipInstsMap);
1779 // This interval may span multiple basic blocks.
1780 // Insert a DBG_VALUE into each one.
1781 while (Stop > MBBEnd) {
1782 // Move to the next block.
1783 Start = MBBEnd;
1784 if (++MBB == MFEnd)
1785 break;
1786 MBBEnd = LIS.getMBBEndIdx(&*MBB);
1787 LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB) << '-' << MBBEnd)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB) << '-' << MBBEnd; } } while (false)
;
1788 insertDebugValue(&*MBB, Start, Stop, DbgValue, SpilledLocs,
1789 LocSpillOffsets, LIS, TII, TRI, BBSkipInstsMap);
1790 }
1791 LLVM_DEBUG(dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << '\n'; } } while (false)
;
1792 if (MBB == MFEnd)
1793 break;
1794
1795 ++I;
1796 }
1797}
1798
1799void UserLabel::emitDebugLabel(LiveIntervals &LIS, const TargetInstrInfo &TII,
1800 BlockSkipInstsMap &BBSkipInstsMap) {
1801 LLVM_DEBUG(dbgs() << "\t" << loc)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "\t" << loc; } } while
(false)
;
1802 MachineFunction::iterator MBB = LIS.getMBBFromIndex(loc)->getIterator();
1803
1804 LLVM_DEBUG(dbgs() << ' ' << printMBBReference(*MBB))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << ' ' << printMBBReference
(*MBB); } } while (false)
;
1805 insertDebugLabel(&*MBB, loc, LIS, TII, BBSkipInstsMap);
1806
1807 LLVM_DEBUG(dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << '\n'; } } while (false)
;
1808}
1809
1810void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
1811 LLVM_DEBUG(dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** EMITTING LIVE DEBUG VARIABLES **********\n"
; } } while (false)
;
4
Assuming 'DebugFlag' is false
5
Loop condition is false. Exiting loop
1812 if (!MF)
6
Assuming field 'MF' is non-null
7
Taking false branch
1813 return;
1814
1815 BlockSkipInstsMap BBSkipInstsMap;
1816 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
1817 SpillOffsetMap SpillOffsets;
1818 for (auto &userValue : userValues) {
8
Assuming '__begin1' is not equal to '__end1'
1819 LLVM_DEBUG(userValue->print(dbgs(), TRI))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { userValue->print(dbgs(), TRI); } } while
(false)
;
9
Assuming 'DebugFlag' is false
10
Loop condition is false. Exiting loop
1820 userValue->rewriteLocations(*VRM, *MF, *TII, *TRI, SpillOffsets);
1821 userValue->emitDebugValues(VRM, *LIS, *TII, *TRI, SpillOffsets,
11
Calling 'UserValue::emitDebugValues'
1822 BBSkipInstsMap);
1823 }
1824 LLVM_DEBUG(dbgs() << "********** EMITTING LIVE DEBUG LABELS **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** EMITTING LIVE DEBUG LABELS **********\n"
; } } while (false)
;
1825 for (auto &userLabel : userLabels) {
1826 LLVM_DEBUG(userLabel->print(dbgs(), TRI))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { userLabel->print(dbgs(), TRI); } } while
(false)
;
1827 userLabel->emitDebugLabel(*LIS, *TII, BBSkipInstsMap);
1828 }
1829
1830 LLVM_DEBUG(dbgs() << "********** EMITTING DEBUG PHIS **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** EMITTING DEBUG PHIS **********\n"
; } } while (false)
;
1831
1832 auto Slots = LIS->getSlotIndexes();
1833 for (auto &It : PHIValToPos) {
1834 // For each ex-PHI, identify its physreg location or stack slot, and emit
1835 // a DBG_PHI for it.
1836 unsigned InstNum = It.first;
1837 auto Slot = It.second.SI;
1838 Register Reg = It.second.Reg;
1839 unsigned SubReg = It.second.SubReg;
1840
1841 MachineBasicBlock *OrigMBB = Slots->getMBBFromIndex(Slot);
1842 if (VRM->isAssignedReg(Reg) &&
1843 Register::isPhysicalRegister(VRM->getPhys(Reg))) {
1844 unsigned PhysReg = VRM->getPhys(Reg);
1845 if (SubReg != 0)
1846 PhysReg = TRI->getSubReg(PhysReg, SubReg);
1847
1848 auto Builder = BuildMI(*OrigMBB, OrigMBB->begin(), DebugLoc(),
1849 TII->get(TargetOpcode::DBG_PHI));
1850 Builder.addReg(PhysReg);
1851 Builder.addImm(InstNum);
1852 } else if (VRM->getStackSlot(Reg) != VirtRegMap::NO_STACK_SLOT) {
1853 const MachineRegisterInfo &MRI = MF->getRegInfo();
1854 const TargetRegisterClass *TRC = MRI.getRegClass(Reg);
1855 unsigned SpillSize, SpillOffset;
1856
1857 // Test whether this location is legal with the given subreg.
1858 bool Success =
1859 TII->getStackSlotRange(TRC, SubReg, SpillSize, SpillOffset, *MF);
1860
1861 if (Success) {
1862 auto Builder = BuildMI(*OrigMBB, OrigMBB->begin(), DebugLoc(),
1863 TII->get(TargetOpcode::DBG_PHI));
1864 Builder.addFrameIndex(VRM->getStackSlot(Reg));
1865 Builder.addImm(InstNum);
1866 }
1867 }
1868 // If there was no mapping for a value ID, it's optimized out. Create no
1869 // DBG_PHI, and any variables using this value will become optimized out.
1870 }
1871 MF->DebugPHIPositions.clear();
1872
1873 LLVM_DEBUG(dbgs() << "********** EMITTING INSTR REFERENCES **********\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("livedebugvars")) { dbgs() << "********** EMITTING INSTR REFERENCES **********\n"
; } } while (false)
;
1874
1875 // Re-insert any debug instrs back in the position they were. We must
1876 // re-insert in the same order to ensure that debug instructions don't swap,
1877 // which could re-order assignments. Do so in a batch -- once we find the
1878 // insert position, insert all instructions at the same SlotIdx. They are
1879 // guaranteed to appear in-sequence in StashedDebugInstrs because we insert
1880 // them in order.
1881 for (auto StashIt = StashedDebugInstrs.begin();
1882 StashIt != StashedDebugInstrs.end(); ++StashIt) {
1883 SlotIndex Idx = StashIt->Idx;
1884 MachineBasicBlock *MBB = StashIt->MBB;
1885 MachineInstr *MI = StashIt->MI;
1886
1887 auto EmitInstsHere = [this, &StashIt, MBB, Idx,
1888 MI](MachineBasicBlock::iterator InsertPos) {
1889 // Insert this debug instruction.
1890 MBB->insert(InsertPos, MI);
1891
1892 // Look at subsequent stashed debug instructions: if they're at the same
1893 // index, insert those too.
1894 auto NextItem = std::next(StashIt);
1895 while (NextItem != StashedDebugInstrs.end() && NextItem->Idx == Idx) {
1896 assert(NextItem->MBB == MBB && "Instrs with same slot index should be"(static_cast <bool> (NextItem->MBB == MBB &&
"Instrs with same slot index should be" "in the same block")
? void (0) : __assert_fail ("NextItem->MBB == MBB && \"Instrs with same slot index should be\" \"in the same block\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 1897, __extension__
__PRETTY_FUNCTION__))
1897 "in the same block")(static_cast <bool> (NextItem->MBB == MBB &&
"Instrs with same slot index should be" "in the same block")
? void (0) : __assert_fail ("NextItem->MBB == MBB && \"Instrs with same slot index should be\" \"in the same block\""
, "llvm/lib/CodeGen/LiveDebugVariables.cpp", 1897, __extension__
__PRETTY_FUNCTION__))
;
1898 MBB->insert(InsertPos, NextItem->MI);
1899 StashIt = NextItem;
1900 NextItem = std::next(StashIt);
1901 };
1902 };
1903
1904 // Start block index: find the first non-debug instr in the block, and
1905 // insert before it.
1906 if (Idx == Slots->getMBBStartIdx(MBB)) {
1907 MachineBasicBlock::iterator InsertPos =
1908 findInsertLocation(MBB, Idx, *LIS, BBSkipInstsMap);
1909 EmitInstsHere(InsertPos);
1910 continue;
1911 }
1912
1913 if (MachineInstr *Pos = Slots->getInstructionFromIndex(Idx)) {
1914 // Insert at the end of any debug instructions.
1915 auto PostDebug = std::next(Pos->getIterator());
1916 PostDebug = skipDebugInstructionsForward(PostDebug, MBB->instr_end());
1917 EmitInstsHere(PostDebug);
1918 } else {
1919 // Insert position disappeared; walk forwards through slots until we
1920 // find a new one.
1921 SlotIndex End = Slots->getMBBEndIdx(MBB);
1922 for (; Idx < End; Idx = Slots->getNextNonNullIndex(Idx)) {
1923 Pos = Slots->getInstructionFromIndex(Idx);
1924 if (Pos) {
1925 EmitInstsHere(Pos->getIterator());
1926 break;
1927 }
1928 }
1929
1930 // We have reached the end of the block and didn't find anywhere to
1931 // insert! It's not safe to discard any debug instructions; place them
1932 // in front of the first terminator, or in front of end().
1933 if (Idx >= End) {
1934 auto TermIt = MBB->getFirstTerminator();
1935 EmitInstsHere(TermIt);
1936 }
1937 }
1938 }
1939
1940 EmitDone = true;
1941 BBSkipInstsMap.clear();
1942}
1943
1944void LiveDebugVariables::emitDebugValues(VirtRegMap *VRM) {
1945 if (pImpl)
1
Assuming field 'pImpl' is non-null
2
Taking true branch
1946 static_cast<LDVImpl*>(pImpl)->emitDebugValues(VRM);
3
Calling 'LDVImpl::emitDebugValues'
1947}
1948
1949#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1950LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void LiveDebugVariables::dump() const {
1951 if (pImpl)
1952 static_cast<LDVImpl*>(pImpl)->print(dbgs());
1953}
1954#endif