Bug Summary

File:build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/llvm/lib/CodeGen/RDFGraph.cpp
Warning:line 510, column 17
Called C++ object pointer is null

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 RDFGraph.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-15~++20220420111733+e13d2efed663/build-llvm -resource-dir /usr/lib/llvm-15/lib/clang/15.0.0 -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-15~++20220420111733+e13d2efed663/llvm/lib/CodeGen -I include -I /build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/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-15/lib/clang/15.0.0/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-15~++20220420111733+e13d2efed663/build-llvm=build-llvm -fmacro-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/= -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/build-llvm=build-llvm -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/= -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-15~++20220420111733+e13d2efed663/build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/build-llvm=build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/= -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-2022-04-20-140412-16051-1 -x c++ /build/llvm-toolchain-snapshot-15~++20220420111733+e13d2efed663/llvm/lib/CodeGen/RDFGraph.cpp
1//===- RDFGraph.cpp -------------------------------------------------------===//
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// Target-independent, SSA-based data flow graph for register data flow (RDF).
10//
11#include "llvm/CodeGen/RDFGraph.h"
12#include "llvm/ADT/BitVector.h"
13#include "llvm/ADT/STLExtras.h"
14#include "llvm/ADT/SetVector.h"
15#include "llvm/CodeGen/MachineBasicBlock.h"
16#include "llvm/CodeGen/MachineDominanceFrontier.h"
17#include "llvm/CodeGen/MachineDominators.h"
18#include "llvm/CodeGen/MachineFunction.h"
19#include "llvm/CodeGen/MachineInstr.h"
20#include "llvm/CodeGen/MachineOperand.h"
21#include "llvm/CodeGen/MachineRegisterInfo.h"
22#include "llvm/CodeGen/RDFRegisters.h"
23#include "llvm/CodeGen/TargetInstrInfo.h"
24#include "llvm/CodeGen/TargetLowering.h"
25#include "llvm/CodeGen/TargetRegisterInfo.h"
26#include "llvm/CodeGen/TargetSubtargetInfo.h"
27#include "llvm/IR/Function.h"
28#include "llvm/MC/LaneBitmask.h"
29#include "llvm/MC/MCInstrDesc.h"
30#include "llvm/Support/ErrorHandling.h"
31#include "llvm/Support/raw_ostream.h"
32#include <algorithm>
33#include <cassert>
34#include <cstdint>
35#include <cstring>
36#include <iterator>
37#include <set>
38#include <utility>
39#include <vector>
40
41using namespace llvm;
42using namespace rdf;
43
44// Printing functions. Have them here first, so that the rest of the code
45// can use them.
46namespace llvm {
47namespace rdf {
48
49raw_ostream &operator<< (raw_ostream &OS, const PrintLaneMaskOpt &P) {
50 if (!P.Mask.all())
51 OS << ':' << PrintLaneMask(P.Mask);
52 return OS;
53}
54
55raw_ostream &operator<< (raw_ostream &OS, const Print<RegisterRef> &P) {
56 auto &TRI = P.G.getTRI();
57 if (P.Obj.Reg > 0 && P.Obj.Reg < TRI.getNumRegs())
58 OS << TRI.getName(P.Obj.Reg);
59 else
60 OS << '#' << P.Obj.Reg;
61 OS << PrintLaneMaskOpt(P.Obj.Mask);
62 return OS;
63}
64
65raw_ostream &operator<< (raw_ostream &OS, const Print<NodeId> &P) {
66 auto NA = P.G.addr<NodeBase*>(P.Obj);
67 uint16_t Attrs = NA.Addr->getAttrs();
68 uint16_t Kind = NodeAttrs::kind(Attrs);
69 uint16_t Flags = NodeAttrs::flags(Attrs);
70 switch (NodeAttrs::type(Attrs)) {
71 case NodeAttrs::Code:
72 switch (Kind) {
73 case NodeAttrs::Func: OS << 'f'; break;
74 case NodeAttrs::Block: OS << 'b'; break;
75 case NodeAttrs::Stmt: OS << 's'; break;
76 case NodeAttrs::Phi: OS << 'p'; break;
77 default: OS << "c?"; break;
78 }
79 break;
80 case NodeAttrs::Ref:
81 if (Flags & NodeAttrs::Undef)
82 OS << '/';
83 if (Flags & NodeAttrs::Dead)
84 OS << '\\';
85 if (Flags & NodeAttrs::Preserving)
86 OS << '+';
87 if (Flags & NodeAttrs::Clobbering)
88 OS << '~';
89 switch (Kind) {
90 case NodeAttrs::Use: OS << 'u'; break;
91 case NodeAttrs::Def: OS << 'd'; break;
92 case NodeAttrs::Block: OS << 'b'; break;
93 default: OS << "r?"; break;
94 }
95 break;
96 default:
97 OS << '?';
98 break;
99 }
100 OS << P.Obj;
101 if (Flags & NodeAttrs::Shadow)
102 OS << '"';
103 return OS;
104}
105
106static void printRefHeader(raw_ostream &OS, const NodeAddr<RefNode*> RA,
107 const DataFlowGraph &G) {
108 OS << Print<NodeId>(RA.Id, G) << '<'
109 << Print<RegisterRef>(RA.Addr->getRegRef(G), G) << '>';
110 if (RA.Addr->getFlags() & NodeAttrs::Fixed)
111 OS << '!';
112}
113
114raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<DefNode*>> &P) {
115 printRefHeader(OS, P.Obj, P.G);
116 OS << '(';
117 if (NodeId N = P.Obj.Addr->getReachingDef())
118 OS << Print<NodeId>(N, P.G);
119 OS << ',';
120 if (NodeId N = P.Obj.Addr->getReachedDef())
121 OS << Print<NodeId>(N, P.G);
122 OS << ',';
123 if (NodeId N = P.Obj.Addr->getReachedUse())
124 OS << Print<NodeId>(N, P.G);
125 OS << "):";
126 if (NodeId N = P.Obj.Addr->getSibling())
127 OS << Print<NodeId>(N, P.G);
128 return OS;
129}
130
131raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<UseNode*>> &P) {
132 printRefHeader(OS, P.Obj, P.G);
133 OS << '(';
134 if (NodeId N = P.Obj.Addr->getReachingDef())
135 OS << Print<NodeId>(N, P.G);
136 OS << "):";
137 if (NodeId N = P.Obj.Addr->getSibling())
138 OS << Print<NodeId>(N, P.G);
139 return OS;
140}
141
142raw_ostream &operator<< (raw_ostream &OS,
143 const Print<NodeAddr<PhiUseNode*>> &P) {
144 printRefHeader(OS, P.Obj, P.G);
145 OS << '(';
146 if (NodeId N = P.Obj.Addr->getReachingDef())
147 OS << Print<NodeId>(N, P.G);
148 OS << ',';
149 if (NodeId N = P.Obj.Addr->getPredecessor())
150 OS << Print<NodeId>(N, P.G);
151 OS << "):";
152 if (NodeId N = P.Obj.Addr->getSibling())
153 OS << Print<NodeId>(N, P.G);
154 return OS;
155}
156
157raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<RefNode*>> &P) {
158 switch (P.Obj.Addr->getKind()) {
159 case NodeAttrs::Def:
160 OS << PrintNode<DefNode*>(P.Obj, P.G);
161 break;
162 case NodeAttrs::Use:
163 if (P.Obj.Addr->getFlags() & NodeAttrs::PhiRef)
164 OS << PrintNode<PhiUseNode*>(P.Obj, P.G);
165 else
166 OS << PrintNode<UseNode*>(P.Obj, P.G);
167 break;
168 }
169 return OS;
170}
171
172raw_ostream &operator<< (raw_ostream &OS, const Print<NodeList> &P) {
173 unsigned N = P.Obj.size();
174 for (auto I : P.Obj) {
175 OS << Print<NodeId>(I.Id, P.G);
176 if (--N)
177 OS << ' ';
178 }
179 return OS;
180}
181
182raw_ostream &operator<< (raw_ostream &OS, const Print<NodeSet> &P) {
183 unsigned N = P.Obj.size();
184 for (auto I : P.Obj) {
185 OS << Print<NodeId>(I, P.G);
186 if (--N)
187 OS << ' ';
188 }
189 return OS;
190}
191
192namespace {
193
194 template <typename T>
195 struct PrintListV {
196 PrintListV(const NodeList &L, const DataFlowGraph &G) : List(L), G(G) {}
197
198 using Type = T;
199 const NodeList &List;
200 const DataFlowGraph &G;
201 };
202
203 template <typename T>
204 raw_ostream &operator<< (raw_ostream &OS, const PrintListV<T> &P) {
205 unsigned N = P.List.size();
206 for (NodeAddr<T> A : P.List) {
207 OS << PrintNode<T>(A, P.G);
208 if (--N)
209 OS << ", ";
210 }
211 return OS;
212 }
213
214} // end anonymous namespace
215
216raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<PhiNode*>> &P) {
217 OS << Print<NodeId>(P.Obj.Id, P.G) << ": phi ["
218 << PrintListV<RefNode*>(P.Obj.Addr->members(P.G), P.G) << ']';
219 return OS;
220}
221
222raw_ostream &operator<<(raw_ostream &OS, const Print<NodeAddr<StmtNode *>> &P) {
223 const MachineInstr &MI = *P.Obj.Addr->getCode();
224 unsigned Opc = MI.getOpcode();
225 OS << Print<NodeId>(P.Obj.Id, P.G) << ": " << P.G.getTII().getName(Opc);
226 // Print the target for calls and branches (for readability).
227 if (MI.isCall() || MI.isBranch()) {
228 MachineInstr::const_mop_iterator T =
229 llvm::find_if(MI.operands(),
230 [] (const MachineOperand &Op) -> bool {
231 return Op.isMBB() || Op.isGlobal() || Op.isSymbol();
232 });
233 if (T != MI.operands_end()) {
234 OS << ' ';
235 if (T->isMBB())
236 OS << printMBBReference(*T->getMBB());
237 else if (T->isGlobal())
238 OS << T->getGlobal()->getName();
239 else if (T->isSymbol())
240 OS << T->getSymbolName();
241 }
242 }
243 OS << " [" << PrintListV<RefNode*>(P.Obj.Addr->members(P.G), P.G) << ']';
244 return OS;
245}
246
247raw_ostream &operator<< (raw_ostream &OS,
248 const Print<NodeAddr<InstrNode*>> &P) {
249 switch (P.Obj.Addr->getKind()) {
250 case NodeAttrs::Phi:
251 OS << PrintNode<PhiNode*>(P.Obj, P.G);
252 break;
253 case NodeAttrs::Stmt:
254 OS << PrintNode<StmtNode*>(P.Obj, P.G);
255 break;
256 default:
257 OS << "instr? " << Print<NodeId>(P.Obj.Id, P.G);
258 break;
259 }
260 return OS;
261}
262
263raw_ostream &operator<< (raw_ostream &OS,
264 const Print<NodeAddr<BlockNode*>> &P) {
265 MachineBasicBlock *BB = P.Obj.Addr->getCode();
266 unsigned NP = BB->pred_size();
267 std::vector<int> Ns;
268 auto PrintBBs = [&OS] (std::vector<int> Ns) -> void {
269 unsigned N = Ns.size();
270 for (int I : Ns) {
271 OS << "%bb." << I;
272 if (--N)
273 OS << ", ";
274 }
275 };
276
277 OS << Print<NodeId>(P.Obj.Id, P.G) << ": --- " << printMBBReference(*BB)
278 << " --- preds(" << NP << "): ";
279 for (MachineBasicBlock *B : BB->predecessors())
280 Ns.push_back(B->getNumber());
281 PrintBBs(Ns);
282
283 unsigned NS = BB->succ_size();
284 OS << " succs(" << NS << "): ";
285 Ns.clear();
286 for (MachineBasicBlock *B : BB->successors())
287 Ns.push_back(B->getNumber());
288 PrintBBs(Ns);
289 OS << '\n';
290
291 for (auto I : P.Obj.Addr->members(P.G))
292 OS << PrintNode<InstrNode*>(I, P.G) << '\n';
293 return OS;
294}
295
296raw_ostream &operator<<(raw_ostream &OS, const Print<NodeAddr<FuncNode *>> &P) {
297 OS << "DFG dump:[\n" << Print<NodeId>(P.Obj.Id, P.G) << ": Function: "
298 << P.Obj.Addr->getCode()->getName() << '\n';
299 for (auto I : P.Obj.Addr->members(P.G))
300 OS << PrintNode<BlockNode*>(I, P.G) << '\n';
301 OS << "]\n";
302 return OS;
303}
304
305raw_ostream &operator<< (raw_ostream &OS, const Print<RegisterSet> &P) {
306 OS << '{';
307 for (auto I : P.Obj)
308 OS << ' ' << Print<RegisterRef>(I, P.G);
309 OS << " }";
310 return OS;
311}
312
313raw_ostream &operator<< (raw_ostream &OS, const Print<RegisterAggr> &P) {
314 P.Obj.print(OS);
315 return OS;
316}
317
318raw_ostream &operator<< (raw_ostream &OS,
319 const Print<DataFlowGraph::DefStack> &P) {
320 for (auto I = P.Obj.top(), E = P.Obj.bottom(); I != E; ) {
321 OS << Print<NodeId>(I->Id, P.G)
322 << '<' << Print<RegisterRef>(I->Addr->getRegRef(P.G), P.G) << '>';
323 I.down();
324 if (I != E)
325 OS << ' ';
326 }
327 return OS;
328}
329
330} // end namespace rdf
331} // end namespace llvm
332
333// Node allocation functions.
334//
335// Node allocator is like a slab memory allocator: it allocates blocks of
336// memory in sizes that are multiples of the size of a node. Each block has
337// the same size. Nodes are allocated from the currently active block, and
338// when it becomes full, a new one is created.
339// There is a mapping scheme between node id and its location in a block,
340// and within that block is described in the header file.
341//
342void NodeAllocator::startNewBlock() {
343 void *T = MemPool.Allocate(NodesPerBlock*NodeMemSize, NodeMemSize);
344 char *P = static_cast<char*>(T);
345 Blocks.push_back(P);
346 // Check if the block index is still within the allowed range, i.e. less
347 // than 2^N, where N is the number of bits in NodeId for the block index.
348 // BitsPerIndex is the number of bits per node index.
349 assert((Blocks.size() < ((size_t)1 << (8*sizeof(NodeId)-BitsPerIndex))) &&(static_cast <bool> ((Blocks.size() < ((size_t)1 <<
(8*sizeof(NodeId)-BitsPerIndex))) && "Out of bits for block index"
) ? void (0) : __assert_fail ("(Blocks.size() < ((size_t)1 << (8*sizeof(NodeId)-BitsPerIndex))) && \"Out of bits for block index\""
, "llvm/lib/CodeGen/RDFGraph.cpp", 350, __extension__ __PRETTY_FUNCTION__
))
350 "Out of bits for block index")(static_cast <bool> ((Blocks.size() < ((size_t)1 <<
(8*sizeof(NodeId)-BitsPerIndex))) && "Out of bits for block index"
) ? void (0) : __assert_fail ("(Blocks.size() < ((size_t)1 << (8*sizeof(NodeId)-BitsPerIndex))) && \"Out of bits for block index\""
, "llvm/lib/CodeGen/RDFGraph.cpp", 350, __extension__ __PRETTY_FUNCTION__
))
;
351 ActiveEnd = P;
352}
353
354bool NodeAllocator::needNewBlock() {
355 if (Blocks.empty())
356 return true;
357
358 char *ActiveBegin = Blocks.back();
359 uint32_t Index = (ActiveEnd-ActiveBegin)/NodeMemSize;
360 return Index >= NodesPerBlock;
361}
362
363NodeAddr<NodeBase*> NodeAllocator::New() {
364 if (needNewBlock())
365 startNewBlock();
366
367 uint32_t ActiveB = Blocks.size()-1;
368 uint32_t Index = (ActiveEnd - Blocks[ActiveB])/NodeMemSize;
369 NodeAddr<NodeBase*> NA = { reinterpret_cast<NodeBase*>(ActiveEnd),
370 makeId(ActiveB, Index) };
371 ActiveEnd += NodeMemSize;
372 return NA;
373}
374
375NodeId NodeAllocator::id(const NodeBase *P) const {
376 uintptr_t A = reinterpret_cast<uintptr_t>(P);
377 for (unsigned i = 0, n = Blocks.size(); i != n; ++i) {
378 uintptr_t B = reinterpret_cast<uintptr_t>(Blocks[i]);
379 if (A < B || A >= B + NodesPerBlock*NodeMemSize)
380 continue;
381 uint32_t Idx = (A-B)/NodeMemSize;
382 return makeId(i, Idx);
383 }
384 llvm_unreachable("Invalid node address")::llvm::llvm_unreachable_internal("Invalid node address", "llvm/lib/CodeGen/RDFGraph.cpp"
, 384)
;
385}
386
387void NodeAllocator::clear() {
388 MemPool.Reset();
389 Blocks.clear();
390 ActiveEnd = nullptr;
391}
392
393// Insert node NA after "this" in the circular chain.
394void NodeBase::append(NodeAddr<NodeBase*> NA) {
395 NodeId Nx = Next;
396 // If NA is already "next", do nothing.
397 if (Next != NA.Id) {
398 Next = NA.Id;
399 NA.Addr->Next = Nx;
400 }
401}
402
403// Fundamental node manipulator functions.
404
405// Obtain the register reference from a reference node.
406RegisterRef RefNode::getRegRef(const DataFlowGraph &G) const {
407 assert(NodeAttrs::type(Attrs) == NodeAttrs::Ref)(static_cast <bool> (NodeAttrs::type(Attrs) == NodeAttrs
::Ref) ? void (0) : __assert_fail ("NodeAttrs::type(Attrs) == NodeAttrs::Ref"
, "llvm/lib/CodeGen/RDFGraph.cpp", 407, __extension__ __PRETTY_FUNCTION__
))
;
408 if (NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef)
409 return G.unpack(Ref.PR);
410 assert(Ref.Op != nullptr)(static_cast <bool> (Ref.Op != nullptr) ? void (0) : __assert_fail
("Ref.Op != nullptr", "llvm/lib/CodeGen/RDFGraph.cpp", 410, __extension__
__PRETTY_FUNCTION__))
;
411 return G.makeRegRef(*Ref.Op);
412}
413
414// Set the register reference in the reference node directly (for references
415// in phi nodes).
416void RefNode::setRegRef(RegisterRef RR, DataFlowGraph &G) {
417 assert(NodeAttrs::type(Attrs) == NodeAttrs::Ref)(static_cast <bool> (NodeAttrs::type(Attrs) == NodeAttrs
::Ref) ? void (0) : __assert_fail ("NodeAttrs::type(Attrs) == NodeAttrs::Ref"
, "llvm/lib/CodeGen/RDFGraph.cpp", 417, __extension__ __PRETTY_FUNCTION__
))
;
418 assert(NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef)(static_cast <bool> (NodeAttrs::flags(Attrs) & NodeAttrs
::PhiRef) ? void (0) : __assert_fail ("NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef"
, "llvm/lib/CodeGen/RDFGraph.cpp", 418, __extension__ __PRETTY_FUNCTION__
))
;
419 Ref.PR = G.pack(RR);
420}
421
422// Set the register reference in the reference node based on a machine
423// operand (for references in statement nodes).
424void RefNode::setRegRef(MachineOperand *Op, DataFlowGraph &G) {
425 assert(NodeAttrs::type(Attrs) == NodeAttrs::Ref)(static_cast <bool> (NodeAttrs::type(Attrs) == NodeAttrs
::Ref) ? void (0) : __assert_fail ("NodeAttrs::type(Attrs) == NodeAttrs::Ref"
, "llvm/lib/CodeGen/RDFGraph.cpp", 425, __extension__ __PRETTY_FUNCTION__
))
;
426 assert(!(NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef))(static_cast <bool> (!(NodeAttrs::flags(Attrs) & NodeAttrs
::PhiRef)) ? void (0) : __assert_fail ("!(NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef)"
, "llvm/lib/CodeGen/RDFGraph.cpp", 426, __extension__ __PRETTY_FUNCTION__
))
;
427 (void)G;
428 Ref.Op = Op;
429}
430
431// Get the owner of a given reference node.
432NodeAddr<NodeBase*> RefNode::getOwner(const DataFlowGraph &G) {
433 NodeAddr<NodeBase*> NA = G.addr<NodeBase*>(getNext());
434
435 while (NA.Addr != this) {
436 if (NA.Addr->getType() == NodeAttrs::Code)
437 return NA;
438 NA = G.addr<NodeBase*>(NA.Addr->getNext());
439 }
440 llvm_unreachable("No owner in circular list")::llvm::llvm_unreachable_internal("No owner in circular list"
, "llvm/lib/CodeGen/RDFGraph.cpp", 440)
;
441}
442
443// Connect the def node to the reaching def node.
444void DefNode::linkToDef(NodeId Self, NodeAddr<DefNode*> DA) {
445 Ref.RD = DA.Id;
446 Ref.Sib = DA.Addr->getReachedDef();
447 DA.Addr->setReachedDef(Self);
448}
449
450// Connect the use node to the reaching def node.
451void UseNode::linkToDef(NodeId Self, NodeAddr<DefNode*> DA) {
452 Ref.RD = DA.Id;
453 Ref.Sib = DA.Addr->getReachedUse();
454 DA.Addr->setReachedUse(Self);
455}
456
457// Get the first member of the code node.
458NodeAddr<NodeBase*> CodeNode::getFirstMember(const DataFlowGraph &G) const {
459 if (Code.FirstM == 0)
460 return NodeAddr<NodeBase*>();
461 return G.addr<NodeBase*>(Code.FirstM);
462}
463
464// Get the last member of the code node.
465NodeAddr<NodeBase*> CodeNode::getLastMember(const DataFlowGraph &G) const {
466 if (Code.LastM == 0)
467 return NodeAddr<NodeBase*>();
468 return G.addr<NodeBase*>(Code.LastM);
469}
470
471// Add node NA at the end of the member list of the given code node.
472void CodeNode::addMember(NodeAddr<NodeBase*> NA, const DataFlowGraph &G) {
473 NodeAddr<NodeBase*> ML = getLastMember(G);
474 if (ML.Id != 0) {
475 ML.Addr->append(NA);
476 } else {
477 Code.FirstM = NA.Id;
478 NodeId Self = G.id(this);
479 NA.Addr->setNext(Self);
480 }
481 Code.LastM = NA.Id;
482}
483
484// Add node NA after member node MA in the given code node.
485void CodeNode::addMemberAfter(NodeAddr<NodeBase*> MA, NodeAddr<NodeBase*> NA,
486 const DataFlowGraph &G) {
487 MA.Addr->append(NA);
488 if (Code.LastM == MA.Id)
489 Code.LastM = NA.Id;
490}
491
492// Remove member node NA from the given code node.
493void CodeNode::removeMember(NodeAddr<NodeBase*> NA, const DataFlowGraph &G) {
494 NodeAddr<NodeBase*> MA = getFirstMember(G);
495 assert(MA.Id != 0)(static_cast <bool> (MA.Id != 0) ? void (0) : __assert_fail
("MA.Id != 0", "llvm/lib/CodeGen/RDFGraph.cpp", 495, __extension__
__PRETTY_FUNCTION__))
;
22
'?' condition is true
496
497 // Special handling if the member to remove is the first member.
498 if (MA.Id == NA.Id) {
23
Assuming 'MA.Id' is not equal to 'NA.Id'
24
Taking false branch
499 if (Code.LastM == MA.Id) {
500 // If it is the only member, set both first and last to 0.
501 Code.FirstM = Code.LastM = 0;
502 } else {
503 // Otherwise, advance the first member.
504 Code.FirstM = MA.Addr->getNext();
505 }
506 return;
507 }
508
509 while (MA.Addr != this) {
25
Assuming the condition is true
26
Loop condition is true. Entering loop body
30
Loop condition is true. Entering loop body
510 NodeId MX = MA.Addr->getNext();
31
Called C++ object pointer is null
511 if (MX == NA.Id) {
27
Assuming 'MX' is not equal to field 'Id'
28
Taking false branch
512 MA.Addr->setNext(NA.Addr->getNext());
513 // If the member to remove happens to be the last one, update the
514 // LastM indicator.
515 if (Code.LastM == NA.Id)
516 Code.LastM = MA.Id;
517 return;
518 }
519 MA = G.addr<NodeBase*>(MX);
29
Null pointer value stored to 'MA.Addr'
520 }
521 llvm_unreachable("No such member")::llvm::llvm_unreachable_internal("No such member", "llvm/lib/CodeGen/RDFGraph.cpp"
, 521)
;
522}
523
524// Return the list of all members of the code node.
525NodeList CodeNode::members(const DataFlowGraph &G) const {
526 static auto True = [] (NodeAddr<NodeBase*>) -> bool { return true; };
527 return members_if(True, G);
528}
529
530// Return the owner of the given instr node.
531NodeAddr<NodeBase*> InstrNode::getOwner(const DataFlowGraph &G) {
532 NodeAddr<NodeBase*> NA = G.addr<NodeBase*>(getNext());
533
534 while (NA.Addr != this) {
535 assert(NA.Addr->getType() == NodeAttrs::Code)(static_cast <bool> (NA.Addr->getType() == NodeAttrs
::Code) ? void (0) : __assert_fail ("NA.Addr->getType() == NodeAttrs::Code"
, "llvm/lib/CodeGen/RDFGraph.cpp", 535, __extension__ __PRETTY_FUNCTION__
))
;
536 if (NA.Addr->getKind() == NodeAttrs::Block)
537 return NA;
538 NA = G.addr<NodeBase*>(NA.Addr->getNext());
539 }
540 llvm_unreachable("No owner in circular list")::llvm::llvm_unreachable_internal("No owner in circular list"
, "llvm/lib/CodeGen/RDFGraph.cpp", 540)
;
541}
542
543// Add the phi node PA to the given block node.
544void BlockNode::addPhi(NodeAddr<PhiNode*> PA, const DataFlowGraph &G) {
545 NodeAddr<NodeBase*> M = getFirstMember(G);
546 if (M.Id == 0) {
547 addMember(PA, G);
548 return;
549 }
550
551 assert(M.Addr->getType() == NodeAttrs::Code)(static_cast <bool> (M.Addr->getType() == NodeAttrs::
Code) ? void (0) : __assert_fail ("M.Addr->getType() == NodeAttrs::Code"
, "llvm/lib/CodeGen/RDFGraph.cpp", 551, __extension__ __PRETTY_FUNCTION__
))
;
552 if (M.Addr->getKind() == NodeAttrs::Stmt) {
553 // If the first member of the block is a statement, insert the phi as
554 // the first member.
555 Code.FirstM = PA.Id;
556 PA.Addr->setNext(M.Id);
557 } else {
558 // If the first member is a phi, find the last phi, and append PA to it.
559 assert(M.Addr->getKind() == NodeAttrs::Phi)(static_cast <bool> (M.Addr->getKind() == NodeAttrs::
Phi) ? void (0) : __assert_fail ("M.Addr->getKind() == NodeAttrs::Phi"
, "llvm/lib/CodeGen/RDFGraph.cpp", 559, __extension__ __PRETTY_FUNCTION__
))
;
560 NodeAddr<NodeBase*> MN = M;
561 do {
562 M = MN;
563 MN = G.addr<NodeBase*>(M.Addr->getNext());
564 assert(MN.Addr->getType() == NodeAttrs::Code)(static_cast <bool> (MN.Addr->getType() == NodeAttrs
::Code) ? void (0) : __assert_fail ("MN.Addr->getType() == NodeAttrs::Code"
, "llvm/lib/CodeGen/RDFGraph.cpp", 564, __extension__ __PRETTY_FUNCTION__
))
;
565 } while (MN.Addr->getKind() == NodeAttrs::Phi);
566
567 // M is the last phi.
568 addMemberAfter(M, PA, G);
569 }
570}
571
572// Find the block node corresponding to the machine basic block BB in the
573// given func node.
574NodeAddr<BlockNode*> FuncNode::findBlock(const MachineBasicBlock *BB,
575 const DataFlowGraph &G) const {
576 auto EqBB = [BB] (NodeAddr<NodeBase*> NA) -> bool {
577 return NodeAddr<BlockNode*>(NA).Addr->getCode() == BB;
578 };
579 NodeList Ms = members_if(EqBB, G);
580 if (!Ms.empty())
581 return Ms[0];
582 return NodeAddr<BlockNode*>();
583}
584
585// Get the block node for the entry block in the given function.
586NodeAddr<BlockNode*> FuncNode::getEntryBlock(const DataFlowGraph &G) {
587 MachineBasicBlock *EntryB = &getCode()->front();
588 return findBlock(EntryB, G);
589}
590
591// Target operand information.
592//
593
594// For a given instruction, check if there are any bits of RR that can remain
595// unchanged across this def.
596bool TargetOperandInfo::isPreserving(const MachineInstr &In, unsigned OpNum)
597 const {
598 return TII.isPredicated(In);
599}
600
601// Check if the definition of RR produces an unspecified value.
602bool TargetOperandInfo::isClobbering(const MachineInstr &In, unsigned OpNum)
603 const {
604 const MachineOperand &Op = In.getOperand(OpNum);
605 if (Op.isRegMask())
606 return true;
607 assert(Op.isReg())(static_cast <bool> (Op.isReg()) ? void (0) : __assert_fail
("Op.isReg()", "llvm/lib/CodeGen/RDFGraph.cpp", 607, __extension__
__PRETTY_FUNCTION__))
;
608 if (In.isCall())
609 if (Op.isDef() && Op.isDead())
610 return true;
611 return false;
612}
613
614// Check if the given instruction specifically requires
615bool TargetOperandInfo::isFixedReg(const MachineInstr &In, unsigned OpNum)
616 const {
617 if (In.isCall() || In.isReturn() || In.isInlineAsm())
618 return true;
619 // Check for a tail call.
620 if (In.isBranch())
621 for (const MachineOperand &O : In.operands())
622 if (O.isGlobal() || O.isSymbol())
623 return true;
624
625 const MCInstrDesc &D = In.getDesc();
626 if (!D.getImplicitDefs() && !D.getImplicitUses())
627 return false;
628 const MachineOperand &Op = In.getOperand(OpNum);
629 // If there is a sub-register, treat the operand as non-fixed. Currently,
630 // fixed registers are those that are listed in the descriptor as implicit
631 // uses or defs, and those lists do not allow sub-registers.
632 if (Op.getSubReg() != 0)
633 return false;
634 Register Reg = Op.getReg();
635 const MCPhysReg *ImpR = Op.isDef() ? D.getImplicitDefs()
636 : D.getImplicitUses();
637 if (!ImpR)
638 return false;
639 while (*ImpR)
640 if (*ImpR++ == Reg)
641 return true;
642 return false;
643}
644
645//
646// The data flow graph construction.
647//
648
649DataFlowGraph::DataFlowGraph(MachineFunction &mf, const TargetInstrInfo &tii,
650 const TargetRegisterInfo &tri, const MachineDominatorTree &mdt,
651 const MachineDominanceFrontier &mdf, const TargetOperandInfo &toi)
652 : MF(mf), TII(tii), TRI(tri), PRI(tri, mf), MDT(mdt), MDF(mdf), TOI(toi),
653 LiveIns(PRI) {
654}
655
656// The implementation of the definition stack.
657// Each register reference has its own definition stack. In particular,
658// for a register references "Reg" and "Reg:subreg" will each have their
659// own definition stacks.
660
661// Construct a stack iterator.
662DataFlowGraph::DefStack::Iterator::Iterator(const DataFlowGraph::DefStack &S,
663 bool Top) : DS(S) {
664 if (!Top) {
665 // Initialize to bottom.
666 Pos = 0;
667 return;
668 }
669 // Initialize to the top, i.e. top-most non-delimiter (or 0, if empty).
670 Pos = DS.Stack.size();
671 while (Pos > 0 && DS.isDelimiter(DS.Stack[Pos-1]))
672 Pos--;
673}
674
675// Return the size of the stack, including block delimiters.
676unsigned DataFlowGraph::DefStack::size() const {
677 unsigned S = 0;
678 for (auto I = top(), E = bottom(); I != E; I.down())
679 S++;
680 return S;
681}
682
683// Remove the top entry from the stack. Remove all intervening delimiters
684// so that after this, the stack is either empty, or the top of the stack
685// is a non-delimiter.
686void DataFlowGraph::DefStack::pop() {
687 assert(!empty())(static_cast <bool> (!empty()) ? void (0) : __assert_fail
("!empty()", "llvm/lib/CodeGen/RDFGraph.cpp", 687, __extension__
__PRETTY_FUNCTION__))
;
688 unsigned P = nextDown(Stack.size());
689 Stack.resize(P);
690}
691
692// Push a delimiter for block node N on the stack.
693void DataFlowGraph::DefStack::start_block(NodeId N) {
694 assert(N != 0)(static_cast <bool> (N != 0) ? void (0) : __assert_fail
("N != 0", "llvm/lib/CodeGen/RDFGraph.cpp", 694, __extension__
__PRETTY_FUNCTION__))
;
695 Stack.push_back(NodeAddr<DefNode*>(nullptr, N));
696}
697
698// Remove all nodes from the top of the stack, until the delimited for
699// block node N is encountered. Remove the delimiter as well. In effect,
700// this will remove from the stack all definitions from block N.
701void DataFlowGraph::DefStack::clear_block(NodeId N) {
702 assert(N != 0)(static_cast <bool> (N != 0) ? void (0) : __assert_fail
("N != 0", "llvm/lib/CodeGen/RDFGraph.cpp", 702, __extension__
__PRETTY_FUNCTION__))
;
703 unsigned P = Stack.size();
704 while (P > 0) {
705 bool Found = isDelimiter(Stack[P-1], N);
706 P--;
707 if (Found)
708 break;
709 }
710 // This will also remove the delimiter, if found.
711 Stack.resize(P);
712}
713
714// Move the stack iterator up by one.
715unsigned DataFlowGraph::DefStack::nextUp(unsigned P) const {
716 // Get the next valid position after P (skipping all delimiters).
717 // The input position P does not have to point to a non-delimiter.
718 unsigned SS = Stack.size();
719 bool IsDelim;
720 assert(P < SS)(static_cast <bool> (P < SS) ? void (0) : __assert_fail
("P < SS", "llvm/lib/CodeGen/RDFGraph.cpp", 720, __extension__
__PRETTY_FUNCTION__))
;
721 do {
722 P++;
723 IsDelim = isDelimiter(Stack[P-1]);
724 } while (P < SS && IsDelim);
725 assert(!IsDelim)(static_cast <bool> (!IsDelim) ? void (0) : __assert_fail
("!IsDelim", "llvm/lib/CodeGen/RDFGraph.cpp", 725, __extension__
__PRETTY_FUNCTION__))
;
726 return P;
727}
728
729// Move the stack iterator down by one.
730unsigned DataFlowGraph::DefStack::nextDown(unsigned P) const {
731 // Get the preceding valid position before P (skipping all delimiters).
732 // The input position P does not have to point to a non-delimiter.
733 assert(P > 0 && P <= Stack.size())(static_cast <bool> (P > 0 && P <= Stack.
size()) ? void (0) : __assert_fail ("P > 0 && P <= Stack.size()"
, "llvm/lib/CodeGen/RDFGraph.cpp", 733, __extension__ __PRETTY_FUNCTION__
))
;
734 bool IsDelim = isDelimiter(Stack[P-1]);
735 do {
736 if (--P == 0)
737 break;
738 IsDelim = isDelimiter(Stack[P-1]);
739 } while (P > 0 && IsDelim);
740 assert(!IsDelim)(static_cast <bool> (!IsDelim) ? void (0) : __assert_fail
("!IsDelim", "llvm/lib/CodeGen/RDFGraph.cpp", 740, __extension__
__PRETTY_FUNCTION__))
;
741 return P;
742}
743
744// Register information.
745
746RegisterSet DataFlowGraph::getLandingPadLiveIns() const {
747 RegisterSet LR;
748 const Function &F = MF.getFunction();
749 const Constant *PF = F.hasPersonalityFn() ? F.getPersonalityFn()
750 : nullptr;
751 const TargetLowering &TLI = *MF.getSubtarget().getTargetLowering();
752 if (RegisterId R = TLI.getExceptionPointerRegister(PF))
753 LR.insert(RegisterRef(R));
754 if (!isFuncletEHPersonality(classifyEHPersonality(PF))) {
755 if (RegisterId R = TLI.getExceptionSelectorRegister(PF))
756 LR.insert(RegisterRef(R));
757 }
758 return LR;
759}
760
761// Node management functions.
762
763// Get the pointer to the node with the id N.
764NodeBase *DataFlowGraph::ptr(NodeId N) const {
765 if (N == 0)
766 return nullptr;
767 return Memory.ptr(N);
768}
769
770// Get the id of the node at the address P.
771NodeId DataFlowGraph::id(const NodeBase *P) const {
772 if (P == nullptr)
773 return 0;
774 return Memory.id(P);
775}
776
777// Allocate a new node and set the attributes to Attrs.
778NodeAddr<NodeBase*> DataFlowGraph::newNode(uint16_t Attrs) {
779 NodeAddr<NodeBase*> P = Memory.New();
780 P.Addr->init();
781 P.Addr->setAttrs(Attrs);
782 return P;
783}
784
785// Make a copy of the given node B, except for the data-flow links, which
786// are set to 0.
787NodeAddr<NodeBase*> DataFlowGraph::cloneNode(const NodeAddr<NodeBase*> B) {
788 NodeAddr<NodeBase*> NA = newNode(0);
789 memcpy(NA.Addr, B.Addr, sizeof(NodeBase));
790 // Ref nodes need to have the data-flow links reset.
791 if (NA.Addr->getType() == NodeAttrs::Ref) {
792 NodeAddr<RefNode*> RA = NA;
793 RA.Addr->setReachingDef(0);
794 RA.Addr->setSibling(0);
795 if (NA.Addr->getKind() == NodeAttrs::Def) {
796 NodeAddr<DefNode*> DA = NA;
797 DA.Addr->setReachedDef(0);
798 DA.Addr->setReachedUse(0);
799 }
800 }
801 return NA;
802}
803
804// Allocation routines for specific node types/kinds.
805
806NodeAddr<UseNode*> DataFlowGraph::newUse(NodeAddr<InstrNode*> Owner,
807 MachineOperand &Op, uint16_t Flags) {
808 NodeAddr<UseNode*> UA = newNode(NodeAttrs::Ref | NodeAttrs::Use | Flags);
809 UA.Addr->setRegRef(&Op, *this);
810 return UA;
811}
812
813NodeAddr<PhiUseNode*> DataFlowGraph::newPhiUse(NodeAddr<PhiNode*> Owner,
814 RegisterRef RR, NodeAddr<BlockNode*> PredB, uint16_t Flags) {
815 NodeAddr<PhiUseNode*> PUA = newNode(NodeAttrs::Ref | NodeAttrs::Use | Flags);
816 assert(Flags & NodeAttrs::PhiRef)(static_cast <bool> (Flags & NodeAttrs::PhiRef) ? void
(0) : __assert_fail ("Flags & NodeAttrs::PhiRef", "llvm/lib/CodeGen/RDFGraph.cpp"
, 816, __extension__ __PRETTY_FUNCTION__))
;
817 PUA.Addr->setRegRef(RR, *this);
818 PUA.Addr->setPredecessor(PredB.Id);
819 return PUA;
820}
821
822NodeAddr<DefNode*> DataFlowGraph::newDef(NodeAddr<InstrNode*> Owner,
823 MachineOperand &Op, uint16_t Flags) {
824 NodeAddr<DefNode*> DA = newNode(NodeAttrs::Ref | NodeAttrs::Def | Flags);
825 DA.Addr->setRegRef(&Op, *this);
826 return DA;
827}
828
829NodeAddr<DefNode*> DataFlowGraph::newDef(NodeAddr<InstrNode*> Owner,
830 RegisterRef RR, uint16_t Flags) {
831 NodeAddr<DefNode*> DA = newNode(NodeAttrs::Ref | NodeAttrs::Def | Flags);
832 assert(Flags & NodeAttrs::PhiRef)(static_cast <bool> (Flags & NodeAttrs::PhiRef) ? void
(0) : __assert_fail ("Flags & NodeAttrs::PhiRef", "llvm/lib/CodeGen/RDFGraph.cpp"
, 832, __extension__ __PRETTY_FUNCTION__))
;
833 DA.Addr->setRegRef(RR, *this);
834 return DA;
835}
836
837NodeAddr<PhiNode*> DataFlowGraph::newPhi(NodeAddr<BlockNode*> Owner) {
838 NodeAddr<PhiNode*> PA = newNode(NodeAttrs::Code | NodeAttrs::Phi);
839 Owner.Addr->addPhi(PA, *this);
840 return PA;
841}
842
843NodeAddr<StmtNode*> DataFlowGraph::newStmt(NodeAddr<BlockNode*> Owner,
844 MachineInstr *MI) {
845 NodeAddr<StmtNode*> SA = newNode(NodeAttrs::Code | NodeAttrs::Stmt);
846 SA.Addr->setCode(MI);
847 Owner.Addr->addMember(SA, *this);
848 return SA;
849}
850
851NodeAddr<BlockNode*> DataFlowGraph::newBlock(NodeAddr<FuncNode*> Owner,
852 MachineBasicBlock *BB) {
853 NodeAddr<BlockNode*> BA = newNode(NodeAttrs::Code | NodeAttrs::Block);
854 BA.Addr->setCode(BB);
855 Owner.Addr->addMember(BA, *this);
856 return BA;
857}
858
859NodeAddr<FuncNode*> DataFlowGraph::newFunc(MachineFunction *MF) {
860 NodeAddr<FuncNode*> FA = newNode(NodeAttrs::Code | NodeAttrs::Func);
861 FA.Addr->setCode(MF);
862 return FA;
863}
864
865// Build the data flow graph.
866void DataFlowGraph::build(unsigned Options) {
867 reset();
868 Func = newFunc(&MF);
869
870 if (MF.empty())
1
Assuming the condition is false
2
Taking false branch
871 return;
872
873 for (MachineBasicBlock &B : MF) {
874 NodeAddr<BlockNode*> BA = newBlock(Func, &B);
875 BlockNodes.insert(std::make_pair(&B, BA));
876 for (MachineInstr &I : B) {
877 if (I.isDebugInstr())
878 continue;
879 buildStmt(BA, I);
880 }
881 }
882
883 NodeAddr<BlockNode*> EA = Func.Addr->getEntryBlock(*this);
884 NodeList Blocks = Func.Addr->members(*this);
885
886 // Collect information about block references.
887 RegisterSet AllRefs;
888 for (NodeAddr<BlockNode*> BA : Blocks)
3
Assuming '__begin1' is equal to '__end1'
889 for (NodeAddr<InstrNode*> IA : BA.Addr->members(*this))
890 for (NodeAddr<RefNode*> RA : IA.Addr->members(*this))
891 AllRefs.insert(RA.Addr->getRegRef(*this));
892
893 // Collect function live-ins and entry block live-ins.
894 MachineRegisterInfo &MRI = MF.getRegInfo();
895 MachineBasicBlock &EntryB = *EA.Addr->getCode();
896 assert(EntryB.pred_empty() && "Function entry block has predecessors")(static_cast <bool> (EntryB.pred_empty() && "Function entry block has predecessors"
) ? void (0) : __assert_fail ("EntryB.pred_empty() && \"Function entry block has predecessors\""
, "llvm/lib/CodeGen/RDFGraph.cpp", 896, __extension__ __PRETTY_FUNCTION__
))
;
4
Assuming the condition is true
5
'?' condition is true
897 for (std::pair<unsigned,unsigned> P : MRI.liveins())
6
Assuming '__begin1' is equal to '__end1'
898 LiveIns.insert(RegisterRef(P.first));
899 if (MRI.tracksLiveness()) {
7
Taking false branch
900 for (auto I : EntryB.liveins())
901 LiveIns.insert(RegisterRef(I.PhysReg, I.LaneMask));
902 }
903
904 // Add function-entry phi nodes for the live-in registers.
905 //for (std::pair<RegisterId,LaneBitmask> P : LiveIns) {
906 for (auto I = LiveIns.rr_begin(), E = LiveIns.rr_end(); I != E; ++I) {
8
Loop condition is false. Execution continues on line 919
907 RegisterRef RR = *I;
908 NodeAddr<PhiNode*> PA = newPhi(EA);
909 uint16_t PhiFlags = NodeAttrs::PhiRef | NodeAttrs::Preserving;
910 NodeAddr<DefNode*> DA = newDef(PA, RR, PhiFlags);
911 PA.Addr->addMember(DA, *this);
912 }
913
914 // Add phis for landing pads.
915 // Landing pads, unlike usual backs blocks, are not entered through
916 // branches in the program, or fall-throughs from other blocks. They
917 // are entered from the exception handling runtime and target's ABI
918 // may define certain registers as defined on entry to such a block.
919 RegisterSet EHRegs = getLandingPadLiveIns();
920 if (!EHRegs.empty()) {
9
Assuming the condition is false
10
Taking false branch
921 for (NodeAddr<BlockNode*> BA : Blocks) {
922 const MachineBasicBlock &B = *BA.Addr->getCode();
923 if (!B.isEHPad())
924 continue;
925
926 // Prepare a list of NodeIds of the block's predecessors.
927 NodeList Preds;
928 for (MachineBasicBlock *PB : B.predecessors())
929 Preds.push_back(findBlock(PB));
930
931 // Build phi nodes for each live-in.
932 for (RegisterRef RR : EHRegs) {
933 NodeAddr<PhiNode*> PA = newPhi(BA);
934 uint16_t PhiFlags = NodeAttrs::PhiRef | NodeAttrs::Preserving;
935 // Add def:
936 NodeAddr<DefNode*> DA = newDef(PA, RR, PhiFlags);
937 PA.Addr->addMember(DA, *this);
938 // Add uses (no reaching defs for phi uses):
939 for (NodeAddr<BlockNode*> PBA : Preds) {
940 NodeAddr<PhiUseNode*> PUA = newPhiUse(PA, RR, PBA);
941 PA.Addr->addMember(PUA, *this);
942 }
943 }
944 }
945 }
946
947 // Build a map "PhiM" which will contain, for each block, the set
948 // of references that will require phi definitions in that block.
949 BlockRefsMap PhiM;
950 for (NodeAddr<BlockNode*> BA : Blocks)
11
Assuming '__begin1' is equal to '__end1'
951 recordDefsForDF(PhiM, BA);
952 for (NodeAddr<BlockNode*> BA : Blocks)
12
Assuming '__begin1' is equal to '__end1'
953 buildPhis(PhiM, AllRefs, BA);
954
955 // Link all the refs. This will recursively traverse the dominator tree.
956 DefStackMap DM;
957 linkBlockRefs(DM, EA);
958
959 // Finally, remove all unused phi nodes.
960 if (!(Options & BuildOptions::KeepDeadPhis))
13
Assuming the condition is true
14
Taking true branch
961 removeUnusedPhis();
15
Calling 'DataFlowGraph::removeUnusedPhis'
962}
963
964RegisterRef DataFlowGraph::makeRegRef(unsigned Reg, unsigned Sub) const {
965 assert(PhysicalRegisterInfo::isRegMaskId(Reg) ||(static_cast <bool> (PhysicalRegisterInfo::isRegMaskId(
Reg) || Register::isPhysicalRegister(Reg)) ? void (0) : __assert_fail
("PhysicalRegisterInfo::isRegMaskId(Reg) || Register::isPhysicalRegister(Reg)"
, "llvm/lib/CodeGen/RDFGraph.cpp", 966, __extension__ __PRETTY_FUNCTION__
))
966 Register::isPhysicalRegister(Reg))(static_cast <bool> (PhysicalRegisterInfo::isRegMaskId(
Reg) || Register::isPhysicalRegister(Reg)) ? void (0) : __assert_fail
("PhysicalRegisterInfo::isRegMaskId(Reg) || Register::isPhysicalRegister(Reg)"
, "llvm/lib/CodeGen/RDFGraph.cpp", 966, __extension__ __PRETTY_FUNCTION__
))
;
967 assert(Reg != 0)(static_cast <bool> (Reg != 0) ? void (0) : __assert_fail
("Reg != 0", "llvm/lib/CodeGen/RDFGraph.cpp", 967, __extension__
__PRETTY_FUNCTION__))
;
968 if (Sub != 0)
969 Reg = TRI.getSubReg(Reg, Sub);
970 return RegisterRef(Reg);
971}
972
973RegisterRef DataFlowGraph::makeRegRef(const MachineOperand &Op) const {
974 assert(Op.isReg() || Op.isRegMask())(static_cast <bool> (Op.isReg() || Op.isRegMask()) ? void
(0) : __assert_fail ("Op.isReg() || Op.isRegMask()", "llvm/lib/CodeGen/RDFGraph.cpp"
, 974, __extension__ __PRETTY_FUNCTION__))
;
975 if (Op.isReg())
976 return makeRegRef(Op.getReg(), Op.getSubReg());
977 return RegisterRef(PRI.getRegMaskId(Op.getRegMask()), LaneBitmask::getAll());
978}
979
980RegisterRef DataFlowGraph::restrictRef(RegisterRef AR, RegisterRef BR) const {
981 if (AR.Reg == BR.Reg) {
982 LaneBitmask M = AR.Mask & BR.Mask;
983 return M.any() ? RegisterRef(AR.Reg, M) : RegisterRef();
984 }
985 // This isn't strictly correct, because the overlap may happen in the
986 // part masked out.
987 if (PRI.alias(AR, BR))
988 return AR;
989 return RegisterRef();
990}
991
992// For each stack in the map DefM, push the delimiter for block B on it.
993void DataFlowGraph::markBlock(NodeId B, DefStackMap &DefM) {
994 // Push block delimiters.
995 for (auto &P : DefM)
996 P.second.start_block(B);
997}
998
999// Remove all definitions coming from block B from each stack in DefM.
1000void DataFlowGraph::releaseBlock(NodeId B, DefStackMap &DefM) {
1001 // Pop all defs from this block from the definition stack. Defs that were
1002 // added to the map during the traversal of instructions will not have a
1003 // delimiter, but for those, the whole stack will be emptied.
1004 for (auto &P : DefM)
1005 P.second.clear_block(B);
1006
1007 // Finally, remove empty stacks from the map.
1008 for (auto I = DefM.begin(), E = DefM.end(), NextI = I; I != E; I = NextI) {
1009 NextI = std::next(I);
1010 // This preserves the validity of iterators other than I.
1011 if (I->second.empty())
1012 DefM.erase(I);
1013 }
1014}
1015
1016// Push all definitions from the instruction node IA to an appropriate
1017// stack in DefM.
1018void DataFlowGraph::pushAllDefs(NodeAddr<InstrNode*> IA, DefStackMap &DefM) {
1019 pushClobbers(IA, DefM);
1020 pushDefs(IA, DefM);
1021}
1022
1023// Push all definitions from the instruction node IA to an appropriate
1024// stack in DefM.
1025void DataFlowGraph::pushClobbers(NodeAddr<InstrNode*> IA, DefStackMap &DefM) {
1026 NodeSet Visited;
1027 std::set<RegisterId> Defined;
1028
1029 // The important objectives of this function are:
1030 // - to be able to handle instructions both while the graph is being
1031 // constructed, and after the graph has been constructed, and
1032 // - maintain proper ordering of definitions on the stack for each
1033 // register reference:
1034 // - if there are two or more related defs in IA (i.e. coming from
1035 // the same machine operand), then only push one def on the stack,
1036 // - if there are multiple unrelated defs of non-overlapping
1037 // subregisters of S, then the stack for S will have both (in an
1038 // unspecified order), but the order does not matter from the data-
1039 // -flow perspective.
1040
1041 for (NodeAddr<DefNode*> DA : IA.Addr->members_if(IsDef, *this)) {
1042 if (Visited.count(DA.Id))
1043 continue;
1044 if (!(DA.Addr->getFlags() & NodeAttrs::Clobbering))
1045 continue;
1046
1047 NodeList Rel = getRelatedRefs(IA, DA);
1048 NodeAddr<DefNode*> PDA = Rel.front();
1049 RegisterRef RR = PDA.Addr->getRegRef(*this);
1050
1051 // Push the definition on the stack for the register and all aliases.
1052 // The def stack traversal in linkNodeUp will check the exact aliasing.
1053 DefM[RR.Reg].push(DA);
1054 Defined.insert(RR.Reg);
1055 for (RegisterId A : PRI.getAliasSet(RR.Reg)) {
1056 // Check that we don't push the same def twice.
1057 assert(A != RR.Reg)(static_cast <bool> (A != RR.Reg) ? void (0) : __assert_fail
("A != RR.Reg", "llvm/lib/CodeGen/RDFGraph.cpp", 1057, __extension__
__PRETTY_FUNCTION__))
;
1058 if (!Defined.count(A))
1059 DefM[A].push(DA);
1060 }
1061 // Mark all the related defs as visited.
1062 for (NodeAddr<NodeBase*> T : Rel)
1063 Visited.insert(T.Id);
1064 }
1065}
1066
1067// Push all definitions from the instruction node IA to an appropriate
1068// stack in DefM.
1069void DataFlowGraph::pushDefs(NodeAddr<InstrNode*> IA, DefStackMap &DefM) {
1070 NodeSet Visited;
1071#ifndef NDEBUG
1072 std::set<RegisterId> Defined;
1073#endif
1074
1075 // The important objectives of this function are:
1076 // - to be able to handle instructions both while the graph is being
1077 // constructed, and after the graph has been constructed, and
1078 // - maintain proper ordering of definitions on the stack for each
1079 // register reference:
1080 // - if there are two or more related defs in IA (i.e. coming from
1081 // the same machine operand), then only push one def on the stack,
1082 // - if there are multiple unrelated defs of non-overlapping
1083 // subregisters of S, then the stack for S will have both (in an
1084 // unspecified order), but the order does not matter from the data-
1085 // -flow perspective.
1086
1087 for (NodeAddr<DefNode*> DA : IA.Addr->members_if(IsDef, *this)) {
1088 if (Visited.count(DA.Id))
1089 continue;
1090 if (DA.Addr->getFlags() & NodeAttrs::Clobbering)
1091 continue;
1092
1093 NodeList Rel = getRelatedRefs(IA, DA);
1094 NodeAddr<DefNode*> PDA = Rel.front();
1095 RegisterRef RR = PDA.Addr->getRegRef(*this);
1096#ifndef NDEBUG
1097 // Assert if the register is defined in two or more unrelated defs.
1098 // This could happen if there are two or more def operands defining it.
1099 if (!Defined.insert(RR.Reg).second) {
1100 MachineInstr *MI = NodeAddr<StmtNode*>(IA).Addr->getCode();
1101 dbgs() << "Multiple definitions of register: "
1102 << Print<RegisterRef>(RR, *this) << " in\n " << *MI << "in "
1103 << printMBBReference(*MI->getParent()) << '\n';
1104 llvm_unreachable(nullptr)::llvm::llvm_unreachable_internal(nullptr, "llvm/lib/CodeGen/RDFGraph.cpp"
, 1104)
;
1105 }
1106#endif
1107 // Push the definition on the stack for the register and all aliases.
1108 // The def stack traversal in linkNodeUp will check the exact aliasing.
1109 DefM[RR.Reg].push(DA);
1110 for (RegisterId A : PRI.getAliasSet(RR.Reg)) {
1111 // Check that we don't push the same def twice.
1112 assert(A != RR.Reg)(static_cast <bool> (A != RR.Reg) ? void (0) : __assert_fail
("A != RR.Reg", "llvm/lib/CodeGen/RDFGraph.cpp", 1112, __extension__
__PRETTY_FUNCTION__))
;
1113 DefM[A].push(DA);
1114 }
1115 // Mark all the related defs as visited.
1116 for (NodeAddr<NodeBase*> T : Rel)
1117 Visited.insert(T.Id);
1118 }
1119}
1120
1121// Return the list of all reference nodes related to RA, including RA itself.
1122// See "getNextRelated" for the meaning of a "related reference".
1123NodeList DataFlowGraph::getRelatedRefs(NodeAddr<InstrNode*> IA,
1124 NodeAddr<RefNode*> RA) const {
1125 assert(IA.Id != 0 && RA.Id != 0)(static_cast <bool> (IA.Id != 0 && RA.Id != 0) ?
void (0) : __assert_fail ("IA.Id != 0 && RA.Id != 0"
, "llvm/lib/CodeGen/RDFGraph.cpp", 1125, __extension__ __PRETTY_FUNCTION__
))
;
1126
1127 NodeList Refs;
1128 NodeId Start = RA.Id;
1129 do {
1130 Refs.push_back(RA);
1131 RA = getNextRelated(IA, RA);
1132 } while (RA.Id != 0 && RA.Id != Start);
1133 return Refs;
1134}
1135
1136// Clear all information in the graph.
1137void DataFlowGraph::reset() {
1138 Memory.clear();
1139 BlockNodes.clear();
1140 Func = NodeAddr<FuncNode*>();
1141}
1142
1143// Return the next reference node in the instruction node IA that is related
1144// to RA. Conceptually, two reference nodes are related if they refer to the
1145// same instance of a register access, but differ in flags or other minor
1146// characteristics. Specific examples of related nodes are shadow reference
1147// nodes.
1148// Return the equivalent of nullptr if there are no more related references.
1149NodeAddr<RefNode*> DataFlowGraph::getNextRelated(NodeAddr<InstrNode*> IA,
1150 NodeAddr<RefNode*> RA) const {
1151 assert(IA.Id != 0 && RA.Id != 0)(static_cast <bool> (IA.Id != 0 && RA.Id != 0) ?
void (0) : __assert_fail ("IA.Id != 0 && RA.Id != 0"
, "llvm/lib/CodeGen/RDFGraph.cpp", 1151, __extension__ __PRETTY_FUNCTION__
))
;
1152
1153 auto Related = [this,RA](NodeAddr<RefNode*> TA) -> bool {
1154 if (TA.Addr->getKind() != RA.Addr->getKind())
1155 return false;
1156 if (TA.Addr->getRegRef(*this) != RA.Addr->getRegRef(*this))
1157 return false;
1158 return true;
1159 };
1160 auto RelatedStmt = [&Related,RA](NodeAddr<RefNode*> TA) -> bool {
1161 return Related(TA) &&
1162 &RA.Addr->getOp() == &TA.Addr->getOp();
1163 };
1164 auto RelatedPhi = [&Related,RA](NodeAddr<RefNode*> TA) -> bool {
1165 if (!Related(TA))
1166 return false;
1167 if (TA.Addr->getKind() != NodeAttrs::Use)
1168 return true;
1169 // For phi uses, compare predecessor blocks.
1170 const NodeAddr<const PhiUseNode*> TUA = TA;
1171 const NodeAddr<const PhiUseNode*> RUA = RA;
1172 return TUA.Addr->getPredecessor() == RUA.Addr->getPredecessor();
1173 };
1174
1175 RegisterRef RR = RA.Addr->getRegRef(*this);
1176 if (IA.Addr->getKind() == NodeAttrs::Stmt)
1177 return RA.Addr->getNextRef(RR, RelatedStmt, true, *this);
1178 return RA.Addr->getNextRef(RR, RelatedPhi, true, *this);
1179}
1180
1181// Find the next node related to RA in IA that satisfies condition P.
1182// If such a node was found, return a pair where the second element is the
1183// located node. If such a node does not exist, return a pair where the
1184// first element is the element after which such a node should be inserted,
1185// and the second element is a null-address.
1186template <typename Predicate>
1187std::pair<NodeAddr<RefNode*>,NodeAddr<RefNode*>>
1188DataFlowGraph::locateNextRef(NodeAddr<InstrNode*> IA, NodeAddr<RefNode*> RA,
1189 Predicate P) const {
1190 assert(IA.Id != 0 && RA.Id != 0)(static_cast <bool> (IA.Id != 0 && RA.Id != 0) ?
void (0) : __assert_fail ("IA.Id != 0 && RA.Id != 0"
, "llvm/lib/CodeGen/RDFGraph.cpp", 1190, __extension__ __PRETTY_FUNCTION__
))
;
1191
1192 NodeAddr<RefNode*> NA;
1193 NodeId Start = RA.Id;
1194 while (true) {
1195 NA = getNextRelated(IA, RA);
1196 if (NA.Id == 0 || NA.Id == Start)
1197 break;
1198 if (P(NA))
1199 break;
1200 RA = NA;
1201 }
1202
1203 if (NA.Id != 0 && NA.Id != Start)
1204 return std::make_pair(RA, NA);
1205 return std::make_pair(RA, NodeAddr<RefNode*>());
1206}
1207
1208// Get the next shadow node in IA corresponding to RA, and optionally create
1209// such a node if it does not exist.
1210NodeAddr<RefNode*> DataFlowGraph::getNextShadow(NodeAddr<InstrNode*> IA,
1211 NodeAddr<RefNode*> RA, bool Create) {
1212 assert(IA.Id != 0 && RA.Id != 0)(static_cast <bool> (IA.Id != 0 && RA.Id != 0) ?
void (0) : __assert_fail ("IA.Id != 0 && RA.Id != 0"
, "llvm/lib/CodeGen/RDFGraph.cpp", 1212, __extension__ __PRETTY_FUNCTION__
))
;
1213
1214 uint16_t Flags = RA.Addr->getFlags() | NodeAttrs::Shadow;
1215 auto IsShadow = [Flags] (NodeAddr<RefNode*> TA) -> bool {
1216 return TA.Addr->getFlags() == Flags;
1217 };
1218 auto Loc = locateNextRef(IA, RA, IsShadow);
1219 if (Loc.second.Id != 0 || !Create)
1220 return Loc.second;
1221
1222 // Create a copy of RA and mark is as shadow.
1223 NodeAddr<RefNode*> NA = cloneNode(RA);
1224 NA.Addr->setFlags(Flags | NodeAttrs::Shadow);
1225 IA.Addr->addMemberAfter(Loc.first, NA, *this);
1226 return NA;
1227}
1228
1229// Get the next shadow node in IA corresponding to RA. Return null-address
1230// if such a node does not exist.
1231NodeAddr<RefNode*> DataFlowGraph::getNextShadow(NodeAddr<InstrNode*> IA,
1232 NodeAddr<RefNode*> RA) const {
1233 assert(IA.Id != 0 && RA.Id != 0)(static_cast <bool> (IA.Id != 0 && RA.Id != 0) ?
void (0) : __assert_fail ("IA.Id != 0 && RA.Id != 0"
, "llvm/lib/CodeGen/RDFGraph.cpp", 1233, __extension__ __PRETTY_FUNCTION__
))
;
1234 uint16_t Flags = RA.Addr->getFlags() | NodeAttrs::Shadow;
1235 auto IsShadow = [Flags] (NodeAddr<RefNode*> TA) -> bool {
1236 return TA.Addr->getFlags() == Flags;
1237 };
1238 return locateNextRef(IA, RA, IsShadow).second;
1239}
1240
1241// Create a new statement node in the block node BA that corresponds to
1242// the machine instruction MI.
1243void DataFlowGraph::buildStmt(NodeAddr<BlockNode*> BA, MachineInstr &In) {
1244 NodeAddr<StmtNode*> SA = newStmt(BA, &In);
1245
1246 auto isCall = [] (const MachineInstr &In) -> bool {
1247 if (In.isCall())
1248 return true;
1249 // Is tail call?
1250 if (In.isBranch()) {
1251 for (const MachineOperand &Op : In.operands())
1252 if (Op.isGlobal() || Op.isSymbol())
1253 return true;
1254 // Assume indirect branches are calls. This is for the purpose of
1255 // keeping implicit operands, and so it won't hurt on intra-function
1256 // indirect branches.
1257 if (In.isIndirectBranch())
1258 return true;
1259 }
1260 return false;
1261 };
1262
1263 auto isDefUndef = [this] (const MachineInstr &In, RegisterRef DR) -> bool {
1264 // This instruction defines DR. Check if there is a use operand that
1265 // would make DR live on entry to the instruction.
1266 for (const MachineOperand &Op : In.operands()) {
1267 if (!Op.isReg() || Op.getReg() == 0 || !Op.isUse() || Op.isUndef())
1268 continue;
1269 RegisterRef UR = makeRegRef(Op);
1270 if (PRI.alias(DR, UR))
1271 return false;
1272 }
1273 return true;
1274 };
1275
1276 bool IsCall = isCall(In);
1277 unsigned NumOps = In.getNumOperands();
1278
1279 // Avoid duplicate implicit defs. This will not detect cases of implicit
1280 // defs that define registers that overlap, but it is not clear how to
1281 // interpret that in the absence of explicit defs. Overlapping explicit
1282 // defs are likely illegal already.
1283 BitVector DoneDefs(TRI.getNumRegs());
1284 // Process explicit defs first.
1285 for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
1286 MachineOperand &Op = In.getOperand(OpN);
1287 if (!Op.isReg() || !Op.isDef() || Op.isImplicit())
1288 continue;
1289 Register R = Op.getReg();
1290 if (!R || !Register::isPhysicalRegister(R))
1291 continue;
1292 uint16_t Flags = NodeAttrs::None;
1293 if (TOI.isPreserving(In, OpN)) {
1294 Flags |= NodeAttrs::Preserving;
1295 // If the def is preserving, check if it is also undefined.
1296 if (isDefUndef(In, makeRegRef(Op)))
1297 Flags |= NodeAttrs::Undef;
1298 }
1299 if (TOI.isClobbering(In, OpN))
1300 Flags |= NodeAttrs::Clobbering;
1301 if (TOI.isFixedReg(In, OpN))
1302 Flags |= NodeAttrs::Fixed;
1303 if (IsCall && Op.isDead())
1304 Flags |= NodeAttrs::Dead;
1305 NodeAddr<DefNode*> DA = newDef(SA, Op, Flags);
1306 SA.Addr->addMember(DA, *this);
1307 assert(!DoneDefs.test(R))(static_cast <bool> (!DoneDefs.test(R)) ? void (0) : __assert_fail
("!DoneDefs.test(R)", "llvm/lib/CodeGen/RDFGraph.cpp", 1307,
__extension__ __PRETTY_FUNCTION__))
;
1308 DoneDefs.set(R);
1309 }
1310
1311 // Process reg-masks (as clobbers).
1312 BitVector DoneClobbers(TRI.getNumRegs());
1313 for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
1314 MachineOperand &Op = In.getOperand(OpN);
1315 if (!Op.isRegMask())
1316 continue;
1317 uint16_t Flags = NodeAttrs::Clobbering | NodeAttrs::Fixed |
1318 NodeAttrs::Dead;
1319 NodeAddr<DefNode*> DA = newDef(SA, Op, Flags);
1320 SA.Addr->addMember(DA, *this);
1321 // Record all clobbered registers in DoneDefs.
1322 const uint32_t *RM = Op.getRegMask();
1323 for (unsigned i = 1, e = TRI.getNumRegs(); i != e; ++i)
1324 if (!(RM[i/32] & (1u << (i%32))))
1325 DoneClobbers.set(i);
1326 }
1327
1328 // Process implicit defs, skipping those that have already been added
1329 // as explicit.
1330 for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
1331 MachineOperand &Op = In.getOperand(OpN);
1332 if (!Op.isReg() || !Op.isDef() || !Op.isImplicit())
1333 continue;
1334 Register R = Op.getReg();
1335 if (!R || !Register::isPhysicalRegister(R) || DoneDefs.test(R))
1336 continue;
1337 RegisterRef RR = makeRegRef(Op);
1338 uint16_t Flags = NodeAttrs::None;
1339 if (TOI.isPreserving(In, OpN)) {
1340 Flags |= NodeAttrs::Preserving;
1341 // If the def is preserving, check if it is also undefined.
1342 if (isDefUndef(In, RR))
1343 Flags |= NodeAttrs::Undef;
1344 }
1345 if (TOI.isClobbering(In, OpN))
1346 Flags |= NodeAttrs::Clobbering;
1347 if (TOI.isFixedReg(In, OpN))
1348 Flags |= NodeAttrs::Fixed;
1349 if (IsCall && Op.isDead()) {
1350 if (DoneClobbers.test(R))
1351 continue;
1352 Flags |= NodeAttrs::Dead;
1353 }
1354 NodeAddr<DefNode*> DA = newDef(SA, Op, Flags);
1355 SA.Addr->addMember(DA, *this);
1356 DoneDefs.set(R);
1357 }
1358
1359 for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
1360 MachineOperand &Op = In.getOperand(OpN);
1361 if (!Op.isReg() || !Op.isUse())
1362 continue;
1363 Register R = Op.getReg();
1364 if (!R || !Register::isPhysicalRegister(R))
1365 continue;
1366 uint16_t Flags = NodeAttrs::None;
1367 if (Op.isUndef())
1368 Flags |= NodeAttrs::Undef;
1369 if (TOI.isFixedReg(In, OpN))
1370 Flags |= NodeAttrs::Fixed;
1371 NodeAddr<UseNode*> UA = newUse(SA, Op, Flags);
1372 SA.Addr->addMember(UA, *this);
1373 }
1374}
1375
1376// Scan all defs in the block node BA and record in PhiM the locations of
1377// phi nodes corresponding to these defs.
1378void DataFlowGraph::recordDefsForDF(BlockRefsMap &PhiM,
1379 NodeAddr<BlockNode*> BA) {
1380 // Check all defs from block BA and record them in each block in BA's
1381 // iterated dominance frontier. This information will later be used to
1382 // create phi nodes.
1383 MachineBasicBlock *BB = BA.Addr->getCode();
1384 assert(BB)(static_cast <bool> (BB) ? void (0) : __assert_fail ("BB"
, "llvm/lib/CodeGen/RDFGraph.cpp", 1384, __extension__ __PRETTY_FUNCTION__
))
;
1385 auto DFLoc = MDF.find(BB);
1386 if (DFLoc == MDF.end() || DFLoc->second.empty())
1387 return;
1388
1389 // Traverse all instructions in the block and collect the set of all
1390 // defined references. For each reference there will be a phi created
1391 // in the block's iterated dominance frontier.
1392 // This is done to make sure that each defined reference gets only one
1393 // phi node, even if it is defined multiple times.
1394 RegisterSet Defs;
1395 for (NodeAddr<InstrNode*> IA : BA.Addr->members(*this))
1396 for (NodeAddr<RefNode*> RA : IA.Addr->members_if(IsDef, *this))
1397 Defs.insert(RA.Addr->getRegRef(*this));
1398
1399 // Calculate the iterated dominance frontier of BB.
1400 const MachineDominanceFrontier::DomSetType &DF = DFLoc->second;
1401 SetVector<MachineBasicBlock*> IDF(DF.begin(), DF.end());
1402 for (unsigned i = 0; i < IDF.size(); ++i) {
1403 auto F = MDF.find(IDF[i]);
1404 if (F != MDF.end())
1405 IDF.insert(F->second.begin(), F->second.end());
1406 }
1407
1408 // Finally, add the set of defs to each block in the iterated dominance
1409 // frontier.
1410 for (auto DB : IDF) {
1411 NodeAddr<BlockNode*> DBA = findBlock(DB);
1412 PhiM[DBA.Id].insert(Defs.begin(), Defs.end());
1413 }
1414}
1415
1416// Given the locations of phi nodes in the map PhiM, create the phi nodes
1417// that are located in the block node BA.
1418void DataFlowGraph::buildPhis(BlockRefsMap &PhiM, RegisterSet &AllRefs,
1419 NodeAddr<BlockNode*> BA) {
1420 // Check if this blocks has any DF defs, i.e. if there are any defs
1421 // that this block is in the iterated dominance frontier of.
1422 auto HasDF = PhiM.find(BA.Id);
1423 if (HasDF == PhiM.end() || HasDF->second.empty())
1424 return;
1425
1426 // First, remove all R in Refs in such that there exists T in Refs
1427 // such that T covers R. In other words, only leave those refs that
1428 // are not covered by another ref (i.e. maximal with respect to covering).
1429
1430 auto MaxCoverIn = [this] (RegisterRef RR, RegisterSet &RRs) -> RegisterRef {
1431 for (RegisterRef I : RRs)
1432 if (I != RR && RegisterAggr::isCoverOf(I, RR, PRI))
1433 RR = I;
1434 return RR;
1435 };
1436
1437 RegisterSet MaxDF;
1438 for (RegisterRef I : HasDF->second)
1439 MaxDF.insert(MaxCoverIn(I, HasDF->second));
1440
1441 std::vector<RegisterRef> MaxRefs;
1442 for (RegisterRef I : MaxDF)
1443 MaxRefs.push_back(MaxCoverIn(I, AllRefs));
1444
1445 // Now, for each R in MaxRefs, get the alias closure of R. If the closure
1446 // only has R in it, create a phi a def for R. Otherwise, create a phi,
1447 // and add a def for each S in the closure.
1448
1449 // Sort the refs so that the phis will be created in a deterministic order.
1450 llvm::sort(MaxRefs);
1451 // Remove duplicates.
1452 auto NewEnd = std::unique(MaxRefs.begin(), MaxRefs.end());
1453 MaxRefs.erase(NewEnd, MaxRefs.end());
1454
1455 auto Aliased = [this,&MaxRefs](RegisterRef RR,
1456 std::vector<unsigned> &Closure) -> bool {
1457 for (unsigned I : Closure)
1458 if (PRI.alias(RR, MaxRefs[I]))
1459 return true;
1460 return false;
1461 };
1462
1463 // Prepare a list of NodeIds of the block's predecessors.
1464 NodeList Preds;
1465 const MachineBasicBlock *MBB = BA.Addr->getCode();
1466 for (MachineBasicBlock *PB : MBB->predecessors())
1467 Preds.push_back(findBlock(PB));
1468
1469 while (!MaxRefs.empty()) {
1470 // Put the first element in the closure, and then add all subsequent
1471 // elements from MaxRefs to it, if they alias at least one element
1472 // already in the closure.
1473 // ClosureIdx: vector of indices in MaxRefs of members of the closure.
1474 std::vector<unsigned> ClosureIdx = { 0 };
1475 for (unsigned i = 1; i != MaxRefs.size(); ++i)
1476 if (Aliased(MaxRefs[i], ClosureIdx))
1477 ClosureIdx.push_back(i);
1478
1479 // Build a phi for the closure.
1480 unsigned CS = ClosureIdx.size();
1481 NodeAddr<PhiNode*> PA = newPhi(BA);
1482
1483 // Add defs.
1484 for (unsigned X = 0; X != CS; ++X) {
1485 RegisterRef RR = MaxRefs[ClosureIdx[X]];
1486 uint16_t PhiFlags = NodeAttrs::PhiRef | NodeAttrs::Preserving;
1487 NodeAddr<DefNode*> DA = newDef(PA, RR, PhiFlags);
1488 PA.Addr->addMember(DA, *this);
1489 }
1490 // Add phi uses.
1491 for (NodeAddr<BlockNode*> PBA : Preds) {
1492 for (unsigned X = 0; X != CS; ++X) {
1493 RegisterRef RR = MaxRefs[ClosureIdx[X]];
1494 NodeAddr<PhiUseNode*> PUA = newPhiUse(PA, RR, PBA);
1495 PA.Addr->addMember(PUA, *this);
1496 }
1497 }
1498
1499 // Erase from MaxRefs all elements in the closure.
1500 auto Begin = MaxRefs.begin();
1501 for (unsigned Idx : llvm::reverse(ClosureIdx))
1502 MaxRefs.erase(Begin + Idx);
1503 }
1504}
1505
1506// Remove any unneeded phi nodes that were created during the build process.
1507void DataFlowGraph::removeUnusedPhis() {
1508 // This will remove unused phis, i.e. phis where each def does not reach
1509 // any uses or other defs. This will not detect or remove circular phi
1510 // chains that are otherwise dead. Unused/dead phis are created during
1511 // the build process and this function is intended to remove these cases
1512 // that are easily determinable to be unnecessary.
1513
1514 SetVector<NodeId> PhiQ;
1515 for (NodeAddr<BlockNode*> BA : Func.Addr->members(*this)) {
16
Assuming '__begin1' is equal to '__end1'
1516 for (auto P : BA.Addr->members_if(IsPhi, *this))
1517 PhiQ.insert(P.Id);
1518 }
1519
1520 static auto HasUsedDef = [](NodeList &Ms) -> bool {
1521 for (NodeAddr<NodeBase*> M : Ms) {
1522 if (M.Addr->getKind() != NodeAttrs::Def)
1523 continue;
1524 NodeAddr<DefNode*> DA = M;
1525 if (DA.Addr->getReachedDef() != 0 || DA.Addr->getReachedUse() != 0)
1526 return true;
1527 }
1528 return false;
1529 };
1530
1531 // Any phi, if it is removed, may affect other phis (make them dead).
1532 // For each removed phi, collect the potentially affected phis and add
1533 // them back to the queue.
1534 while (!PhiQ.empty()) {
17
Assuming the condition is true
18
Loop condition is true. Entering loop body
1535 auto PA = addr<PhiNode*>(PhiQ[0]);
1536 PhiQ.remove(PA.Id);
1537 NodeList Refs = PA.Addr->members(*this);
1538 if (HasUsedDef(Refs))
19
Taking false branch
1539 continue;
1540 for (NodeAddr<RefNode*> RA : Refs) {
20
Assuming '__begin2' is equal to '__end2'
1541 if (NodeId RD = RA.Addr->getReachingDef()) {
1542 auto RDA = addr<DefNode*>(RD);
1543 NodeAddr<InstrNode*> OA = RDA.Addr->getOwner(*this);
1544 if (IsPhi(OA))
1545 PhiQ.insert(OA.Id);
1546 }
1547 if (RA.Addr->isDef())
1548 unlinkDef(RA, true);
1549 else
1550 unlinkUse(RA, true);
1551 }
1552 NodeAddr<BlockNode*> BA = PA.Addr->getOwner(*this);
1553 BA.Addr->removeMember(PA, *this);
21
Calling 'CodeNode::removeMember'
1554 }
1555}
1556
1557// For a given reference node TA in an instruction node IA, connect the
1558// reaching def of TA to the appropriate def node. Create any shadow nodes
1559// as appropriate.
1560template <typename T>
1561void DataFlowGraph::linkRefUp(NodeAddr<InstrNode*> IA, NodeAddr<T> TA,
1562 DefStack &DS) {
1563 if (DS.empty())
1564 return;
1565 RegisterRef RR = TA.Addr->getRegRef(*this);
1566 NodeAddr<T> TAP;
1567
1568 // References from the def stack that have been examined so far.
1569 RegisterAggr Defs(PRI);
1570
1571 for (auto I = DS.top(), E = DS.bottom(); I != E; I.down()) {
1572 RegisterRef QR = I->Addr->getRegRef(*this);
1573
1574 // Skip all defs that are aliased to any of the defs that we have already
1575 // seen. If this completes a cover of RR, stop the stack traversal.
1576 bool Alias = Defs.hasAliasOf(QR);
1577 bool Cover = Defs.insert(QR).hasCoverOf(RR);
1578 if (Alias) {
1579 if (Cover)
1580 break;
1581 continue;
1582 }
1583
1584 // The reaching def.
1585 NodeAddr<DefNode*> RDA = *I;
1586
1587 // Pick the reached node.
1588 if (TAP.Id == 0) {
1589 TAP = TA;
1590 } else {
1591 // Mark the existing ref as "shadow" and create a new shadow.
1592 TAP.Addr->setFlags(TAP.Addr->getFlags() | NodeAttrs::Shadow);
1593 TAP = getNextShadow(IA, TAP, true);
1594 }
1595
1596 // Create the link.
1597 TAP.Addr->linkToDef(TAP.Id, RDA);
1598
1599 if (Cover)
1600 break;
1601 }
1602}
1603
1604// Create data-flow links for all reference nodes in the statement node SA.
1605template <typename Predicate>
1606void DataFlowGraph::linkStmtRefs(DefStackMap &DefM, NodeAddr<StmtNode*> SA,
1607 Predicate P) {
1608#ifndef NDEBUG
1609 RegisterSet Defs;
1610#endif
1611
1612 // Link all nodes (upwards in the data-flow) with their reaching defs.
1613 for (NodeAddr<RefNode*> RA : SA.Addr->members_if(P, *this)) {
1614 uint16_t Kind = RA.Addr->getKind();
1615 assert(Kind == NodeAttrs::Def || Kind == NodeAttrs::Use)(static_cast <bool> (Kind == NodeAttrs::Def || Kind == NodeAttrs
::Use) ? void (0) : __assert_fail ("Kind == NodeAttrs::Def || Kind == NodeAttrs::Use"
, "llvm/lib/CodeGen/RDFGraph.cpp", 1615, __extension__ __PRETTY_FUNCTION__
))
;
1616 RegisterRef RR = RA.Addr->getRegRef(*this);
1617#ifndef NDEBUG
1618 // Do not expect multiple defs of the same reference.
1619 assert(Kind != NodeAttrs::Def || !Defs.count(RR))(static_cast <bool> (Kind != NodeAttrs::Def || !Defs.count
(RR)) ? void (0) : __assert_fail ("Kind != NodeAttrs::Def || !Defs.count(RR)"
, "llvm/lib/CodeGen/RDFGraph.cpp", 1619, __extension__ __PRETTY_FUNCTION__
))
;
1620 Defs.insert(RR);
1621#endif
1622
1623 auto F = DefM.find(RR.Reg);
1624 if (F == DefM.end())
1625 continue;
1626 DefStack &DS = F->second;
1627 if (Kind == NodeAttrs::Use)
1628 linkRefUp<UseNode*>(SA, RA, DS);
1629 else if (Kind == NodeAttrs::Def)
1630 linkRefUp<DefNode*>(SA, RA, DS);
1631 else
1632 llvm_unreachable("Unexpected node in instruction")::llvm::llvm_unreachable_internal("Unexpected node in instruction"
, "llvm/lib/CodeGen/RDFGraph.cpp", 1632)
;
1633 }
1634}
1635
1636// Create data-flow links for all instructions in the block node BA. This
1637// will include updating any phi nodes in BA.
1638void DataFlowGraph::linkBlockRefs(DefStackMap &DefM, NodeAddr<BlockNode*> BA) {
1639 // Push block delimiters.
1640 markBlock(BA.Id, DefM);
1641
1642 auto IsClobber = [] (NodeAddr<RefNode*> RA) -> bool {
1643 return IsDef(RA) && (RA.Addr->getFlags() & NodeAttrs::Clobbering);
1644 };
1645 auto IsNoClobber = [] (NodeAddr<RefNode*> RA) -> bool {
1646 return IsDef(RA) && !(RA.Addr->getFlags() & NodeAttrs::Clobbering);
1647 };
1648
1649 assert(BA.Addr && "block node address is needed to create a data-flow link")(static_cast <bool> (BA.Addr && "block node address is needed to create a data-flow link"
) ? void (0) : __assert_fail ("BA.Addr && \"block node address is needed to create a data-flow link\""
, "llvm/lib/CodeGen/RDFGraph.cpp", 1649, __extension__ __PRETTY_FUNCTION__
))
;
1650 // For each non-phi instruction in the block, link all the defs and uses
1651 // to their reaching defs. For any member of the block (including phis),
1652 // push the defs on the corresponding stacks.
1653 for (NodeAddr<InstrNode*> IA : BA.Addr->members(*this)) {
1654 // Ignore phi nodes here. They will be linked part by part from the
1655 // predecessors.
1656 if (IA.Addr->getKind() == NodeAttrs::Stmt) {
1657 linkStmtRefs(DefM, IA, IsUse);
1658 linkStmtRefs(DefM, IA, IsClobber);
1659 }
1660
1661 // Push the definitions on the stack.
1662 pushClobbers(IA, DefM);
1663
1664 if (IA.Addr->getKind() == NodeAttrs::Stmt)
1665 linkStmtRefs(DefM, IA, IsNoClobber);
1666
1667 pushDefs(IA, DefM);
1668 }
1669
1670 // Recursively process all children in the dominator tree.
1671 MachineDomTreeNode *N = MDT.getNode(BA.Addr->getCode());
1672 for (auto I : *N) {
1673 MachineBasicBlock *SB = I->getBlock();
1674 NodeAddr<BlockNode*> SBA = findBlock(SB);
1675 linkBlockRefs(DefM, SBA);
1676 }
1677
1678 // Link the phi uses from the successor blocks.
1679 auto IsUseForBA = [BA](NodeAddr<NodeBase*> NA) -> bool {
1680 if (NA.Addr->getKind() != NodeAttrs::Use)
1681 return false;
1682 assert(NA.Addr->getFlags() & NodeAttrs::PhiRef)(static_cast <bool> (NA.Addr->getFlags() & NodeAttrs
::PhiRef) ? void (0) : __assert_fail ("NA.Addr->getFlags() & NodeAttrs::PhiRef"
, "llvm/lib/CodeGen/RDFGraph.cpp", 1682, __extension__ __PRETTY_FUNCTION__
))
;
1683 NodeAddr<PhiUseNode*> PUA = NA;
1684 return PUA.Addr->getPredecessor() == BA.Id;
1685 };
1686
1687 RegisterSet EHLiveIns = getLandingPadLiveIns();
1688 MachineBasicBlock *MBB = BA.Addr->getCode();
1689
1690 for (MachineBasicBlock *SB : MBB->successors()) {
1691 bool IsEHPad = SB->isEHPad();
1692 NodeAddr<BlockNode*> SBA = findBlock(SB);
1693 for (NodeAddr<InstrNode*> IA : SBA.Addr->members_if(IsPhi, *this)) {
1694 // Do not link phi uses for landing pad live-ins.
1695 if (IsEHPad) {
1696 // Find what register this phi is for.
1697 NodeAddr<RefNode*> RA = IA.Addr->getFirstMember(*this);
1698 assert(RA.Id != 0)(static_cast <bool> (RA.Id != 0) ? void (0) : __assert_fail
("RA.Id != 0", "llvm/lib/CodeGen/RDFGraph.cpp", 1698, __extension__
__PRETTY_FUNCTION__))
;
1699 if (EHLiveIns.count(RA.Addr->getRegRef(*this)))
1700 continue;
1701 }
1702 // Go over each phi use associated with MBB, and link it.
1703 for (auto U : IA.Addr->members_if(IsUseForBA, *this)) {
1704 NodeAddr<PhiUseNode*> PUA = U;
1705 RegisterRef RR = PUA.Addr->getRegRef(*this);
1706 linkRefUp<UseNode*>(IA, PUA, DefM[RR.Reg]);
1707 }
1708 }
1709 }
1710
1711 // Pop all defs from this block from the definition stacks.
1712 releaseBlock(BA.Id, DefM);
1713}
1714
1715// Remove the use node UA from any data-flow and structural links.
1716void DataFlowGraph::unlinkUseDF(NodeAddr<UseNode*> UA) {
1717 NodeId RD = UA.Addr->getReachingDef();
1718 NodeId Sib = UA.Addr->getSibling();
1719
1720 if (RD == 0) {
1721 assert(Sib == 0)(static_cast <bool> (Sib == 0) ? void (0) : __assert_fail
("Sib == 0", "llvm/lib/CodeGen/RDFGraph.cpp", 1721, __extension__
__PRETTY_FUNCTION__))
;
1722 return;
1723 }
1724
1725 auto RDA = addr<DefNode*>(RD);
1726 auto TA = addr<UseNode*>(RDA.Addr->getReachedUse());
1727 if (TA.Id == UA.Id) {
1728 RDA.Addr->setReachedUse(Sib);
1729 return;
1730 }
1731
1732 while (TA.Id != 0) {
1733 NodeId S = TA.Addr->getSibling();
1734 if (S == UA.Id) {
1735 TA.Addr->setSibling(UA.Addr->getSibling());
1736 return;
1737 }
1738 TA = addr<UseNode*>(S);
1739 }
1740}
1741
1742// Remove the def node DA from any data-flow and structural links.
1743void DataFlowGraph::unlinkDefDF(NodeAddr<DefNode*> DA) {
1744 //
1745 // RD
1746 // | reached
1747 // | def
1748 // :
1749 // .
1750 // +----+
1751 // ... -- | DA | -- ... -- 0 : sibling chain of DA
1752 // +----+
1753 // | | reached
1754 // | : def
1755 // | .
1756 // | ... : Siblings (defs)
1757 // |
1758 // : reached
1759 // . use
1760 // ... : sibling chain of reached uses
1761
1762 NodeId RD = DA.Addr->getReachingDef();
1763
1764 // Visit all siblings of the reached def and reset their reaching defs.
1765 // Also, defs reached by DA are now "promoted" to being reached by RD,
1766 // so all of them will need to be spliced into the sibling chain where
1767 // DA belongs.
1768 auto getAllNodes = [this] (NodeId N) -> NodeList {
1769 NodeList Res;
1770 while (N) {
1771 auto RA = addr<RefNode*>(N);
1772 // Keep the nodes in the exact sibling order.
1773 Res.push_back(RA);
1774 N = RA.Addr->getSibling();
1775 }
1776 return Res;
1777 };
1778 NodeList ReachedDefs = getAllNodes(DA.Addr->getReachedDef());
1779 NodeList ReachedUses = getAllNodes(DA.Addr->getReachedUse());
1780
1781 if (RD == 0) {
1782 for (NodeAddr<RefNode*> I : ReachedDefs)
1783 I.Addr->setSibling(0);
1784 for (NodeAddr<RefNode*> I : ReachedUses)
1785 I.Addr->setSibling(0);
1786 }
1787 for (NodeAddr<DefNode*> I : ReachedDefs)
1788 I.Addr->setReachingDef(RD);
1789 for (NodeAddr<UseNode*> I : ReachedUses)
1790 I.Addr->setReachingDef(RD);
1791
1792 NodeId Sib = DA.Addr->getSibling();
1793 if (RD == 0) {
1794 assert(Sib == 0)(static_cast <bool> (Sib == 0) ? void (0) : __assert_fail
("Sib == 0", "llvm/lib/CodeGen/RDFGraph.cpp", 1794, __extension__
__PRETTY_FUNCTION__))
;
1795 return;
1796 }
1797
1798 // Update the reaching def node and remove DA from the sibling list.
1799 auto RDA = addr<DefNode*>(RD);
1800 auto TA = addr<DefNode*>(RDA.Addr->getReachedDef());
1801 if (TA.Id == DA.Id) {
1802 // If DA is the first reached def, just update the RD's reached def
1803 // to the DA's sibling.
1804 RDA.Addr->setReachedDef(Sib);
1805 } else {
1806 // Otherwise, traverse the sibling list of the reached defs and remove
1807 // DA from it.
1808 while (TA.Id != 0) {
1809 NodeId S = TA.Addr->getSibling();
1810 if (S == DA.Id) {
1811 TA.Addr->setSibling(Sib);
1812 break;
1813 }
1814 TA = addr<DefNode*>(S);
1815 }
1816 }
1817
1818 // Splice the DA's reached defs into the RDA's reached def chain.
1819 if (!ReachedDefs.empty()) {
1820 auto Last = NodeAddr<DefNode*>(ReachedDefs.back());
1821 Last.Addr->setSibling(RDA.Addr->getReachedDef());
1822 RDA.Addr->setReachedDef(ReachedDefs.front().Id);
1823 }
1824 // Splice the DA's reached uses into the RDA's reached use chain.
1825 if (!ReachedUses.empty()) {
1826 auto Last = NodeAddr<UseNode*>(ReachedUses.back());
1827 Last.Addr->setSibling(RDA.Addr->getReachedUse());
1828 RDA.Addr->setReachedUse(ReachedUses.front().Id);
1829 }
1830}