LLVM  14.0.0git
BasicBlockSections.cpp
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1 //===-- BasicBlockSections.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 // BasicBlockSections implementation.
10 //
11 // The purpose of this pass is to assign sections to basic blocks when
12 // -fbasic-block-sections= option is used. Further, with profile information
13 // only the subset of basic blocks with profiles are placed in separate sections
14 // and the rest are grouped in a cold section. The exception handling blocks are
15 // treated specially to ensure they are all in one seciton.
16 //
17 // Basic Block Sections
18 // ====================
19 //
20 // With option, -fbasic-block-sections=list, every function may be split into
21 // clusters of basic blocks. Every cluster will be emitted into a separate
22 // section with its basic blocks sequenced in the given order. To get the
23 // optimized performance, the clusters must form an optimal BB layout for the
24 // function. We insert a symbol at the beginning of every cluster's section to
25 // allow the linker to reorder the sections in any arbitrary sequence. A global
26 // order of these sections would encapsulate the function layout.
27 // For example, consider the following clusters for a function foo (consisting
28 // of 6 basic blocks 0, 1, ..., 5).
29 //
30 // 0 2
31 // 1 3 5
32 //
33 // * Basic blocks 0 and 2 are placed in one section with symbol `foo`
34 // referencing the beginning of this section.
35 // * Basic blocks 1, 3, 5 are placed in a separate section. A new symbol
36 // `foo.__part.1` will reference the beginning of this section.
37 // * Basic block 4 (note that it is not referenced in the list) is placed in
38 // one section, and a new symbol `foo.cold` will point to it.
39 //
40 // There are a couple of challenges to be addressed:
41 //
42 // 1. The last basic block of every cluster should not have any implicit
43 // fallthrough to its next basic block, as it can be reordered by the linker.
44 // The compiler should make these fallthroughs explicit by adding
45 // unconditional jumps..
46 //
47 // 2. All inter-cluster branch targets would now need to be resolved by the
48 // linker as they cannot be calculated during compile time. This is done
49 // using static relocations. Further, the compiler tries to use short branch
50 // instructions on some ISAs for small branch offsets. This is not possible
51 // for inter-cluster branches as the offset is not determined at compile
52 // time, and therefore, long branch instructions have to be used for those.
53 //
54 // 3. Debug Information (DebugInfo) and Call Frame Information (CFI) emission
55 // needs special handling with basic block sections. DebugInfo needs to be
56 // emitted with more relocations as basic block sections can break a
57 // function into potentially several disjoint pieces, and CFI needs to be
58 // emitted per cluster. This also bloats the object file and binary sizes.
59 //
60 // Basic Block Labels
61 // ==================
62 //
63 // With -fbasic-block-sections=labels, we emit the offsets of BB addresses of
64 // every function into the .llvm_bb_addr_map section. Along with the function
65 // symbols, this allows for mapping of virtual addresses in PMU profiles back to
66 // the corresponding basic blocks. This logic is implemented in AsmPrinter. This
67 // pass only assigns the BBSectionType of every function to ``labels``.
68 //
69 //===----------------------------------------------------------------------===//
70 
71 #include "llvm/ADT/Optional.h"
72 #include "llvm/ADT/SmallSet.h"
73 #include "llvm/ADT/SmallVector.h"
74 #include "llvm/ADT/StringMap.h"
75 #include "llvm/ADT/StringRef.h"
80 #include "llvm/CodeGen/Passes.h"
82 #include "llvm/InitializePasses.h"
83 #include "llvm/Support/Error.h"
87 
88 using llvm::SmallSet;
89 using llvm::SmallVector;
90 using llvm::StringMap;
91 using llvm::StringRef;
92 using namespace llvm;
93 
94 // Placing the cold clusters in a separate section mitigates against poor
95 // profiles and allows optimizations such as hugepage mapping to be applied at a
96 // section granularity. Defaults to ".text.split." which is recognized by lld
97 // via the `-z keep-text-section-prefix` flag.
99  "bbsections-cold-text-prefix",
100  cl::desc("The text prefix to use for cold basic block clusters"),
101  cl::init(".text.split."), cl::Hidden);
102 
104  "bbsections-detect-source-drift",
105  cl::desc("This checks if there is a fdo instr. profile hash "
106  "mismatch for this function"),
107  cl::init(true), cl::Hidden);
108 
109 namespace {
110 
111 // This struct represents the cluster information for a machine basic block.
112 struct BBClusterInfo {
113  // MachineBasicBlock ID.
114  unsigned MBBNumber;
115  // Cluster ID this basic block belongs to.
116  unsigned ClusterID;
117  // Position of basic block within the cluster.
118  unsigned PositionInCluster;
119 };
120 
121 using ProgramBBClusterInfoMapTy = StringMap<SmallVector<BBClusterInfo, 4>>;
122 
123 class BasicBlockSections : public MachineFunctionPass {
124 public:
125  static char ID;
126 
127  // This contains the basic-block-sections profile.
128  const MemoryBuffer *MBuf = nullptr;
129 
130  // This encapsulates the BB cluster information for the whole program.
131  //
132  // For every function name, it contains the cluster information for (all or
133  // some of) its basic blocks. The cluster information for every basic block
134  // includes its cluster ID along with the position of the basic block in that
135  // cluster.
136  ProgramBBClusterInfoMapTy ProgramBBClusterInfo;
137 
138  // Some functions have alias names. We use this map to find the main alias
139  // name for which we have mapping in ProgramBBClusterInfo.
140  StringMap<StringRef> FuncAliasMap;
141 
142  BasicBlockSections(const MemoryBuffer *Buf)
143  : MachineFunctionPass(ID), MBuf(Buf) {
145  };
146 
147  BasicBlockSections() : MachineFunctionPass(ID) {
149  }
150 
151  StringRef getPassName() const override {
152  return "Basic Block Sections Analysis";
153  }
154 
155  void getAnalysisUsage(AnalysisUsage &AU) const override;
156 
157  /// Read profiles of basic blocks if available here.
158  bool doInitialization(Module &M) override;
159 
160  /// Identify basic blocks that need separate sections and prepare to emit them
161  /// accordingly.
162  bool runOnMachineFunction(MachineFunction &MF) override;
163 };
164 
165 } // end anonymous namespace
166 
167 char BasicBlockSections::ID = 0;
168 INITIALIZE_PASS(BasicBlockSections, "bbsections-prepare",
169  "Prepares for basic block sections, by splitting functions "
170  "into clusters of basic blocks.",
171  false, false)
172 
173 // This function updates and optimizes the branching instructions of every basic
174 // block in a given function to account for changes in the layout.
175 static void updateBranches(
176  MachineFunction &MF,
178  const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
180  for (auto &MBB : MF) {
181  auto NextMBBI = std::next(MBB.getIterator());
182  auto *FTMBB = PreLayoutFallThroughs[MBB.getNumber()];
183  // If this block had a fallthrough before we need an explicit unconditional
184  // branch to that block if either
185  // 1- the block ends a section, which means its next block may be
186  // reorderd by the linker, or
187  // 2- the fallthrough block is not adjacent to the block in the new
188  // order.
189  if (FTMBB && (MBB.isEndSection() || &*NextMBBI != FTMBB))
190  TII->insertUnconditionalBranch(MBB, FTMBB, MBB.findBranchDebugLoc());
191 
192  // We do not optimize branches for machine basic blocks ending sections, as
193  // their adjacent block might be reordered by the linker.
194  if (MBB.isEndSection())
195  continue;
196 
197  // It might be possible to optimize branches by flipping the branch
198  // condition.
199  Cond.clear();
200  MachineBasicBlock *TBB = nullptr, *FBB = nullptr; // For analyzeBranch.
201  if (TII->analyzeBranch(MBB, TBB, FBB, Cond))
202  continue;
203  MBB.updateTerminator(FTMBB);
204  }
205 }
206 
207 // This function provides the BBCluster information associated with a function.
208 // Returns true if a valid association exists and false otherwise.
210  const MachineFunction &MF, const StringMap<StringRef> FuncAliasMap,
211  const ProgramBBClusterInfoMapTy &ProgramBBClusterInfo,
212  std::vector<Optional<BBClusterInfo>> &V) {
213  // Get the main alias name for the function.
214  auto FuncName = MF.getName();
215  auto R = FuncAliasMap.find(FuncName);
216  StringRef AliasName = R == FuncAliasMap.end() ? FuncName : R->second;
217 
218  // Find the assoicated cluster information.
219  auto P = ProgramBBClusterInfo.find(AliasName);
220  if (P == ProgramBBClusterInfo.end())
221  return false;
222 
223  if (P->second.empty()) {
224  // This indicates that sections are desired for all basic blocks of this
225  // function. We clear the BBClusterInfo vector to denote this.
226  V.clear();
227  return true;
228  }
229 
230  V.resize(MF.getNumBlockIDs());
231  for (auto bbClusterInfo : P->second) {
232  // Bail out if the cluster information contains invalid MBB numbers.
233  if (bbClusterInfo.MBBNumber >= MF.getNumBlockIDs())
234  return false;
235  V[bbClusterInfo.MBBNumber] = bbClusterInfo;
236  }
237  return true;
238 }
239 
240 // This function sorts basic blocks according to the cluster's information.
241 // All explicitly specified clusters of basic blocks will be ordered
242 // accordingly. All non-specified BBs go into a separate "Cold" section.
243 // Additionally, if exception handling landing pads end up in more than one
244 // clusters, they are moved into a single "Exception" section. Eventually,
245 // clusters are ordered in increasing order of their IDs, with the "Exception"
246 // and "Cold" succeeding all other clusters.
247 // FuncBBClusterInfo represent the cluster information for basic blocks. If this
248 // is empty, it means unique sections for all basic blocks in the function.
249 static void
251  const std::vector<Optional<BBClusterInfo>> &FuncBBClusterInfo) {
252  assert(MF.hasBBSections() && "BB Sections is not set for function.");
253  // This variable stores the section ID of the cluster containing eh_pads (if
254  // all eh_pads are one cluster). If more than one cluster contain eh_pads, we
255  // set it equal to ExceptionSectionID.
256  Optional<MBBSectionID> EHPadsSectionID;
257 
258  for (auto &MBB : MF) {
259  // With the 'all' option, every basic block is placed in a unique section.
260  // With the 'list' option, every basic block is placed in a section
261  // associated with its cluster, unless we want individual unique sections
262  // for every basic block in this function (if FuncBBClusterInfo is empty).
263  if (MF.getTarget().getBBSectionsType() == llvm::BasicBlockSection::All ||
264  FuncBBClusterInfo.empty()) {
265  // If unique sections are desired for all basic blocks of the function, we
266  // set every basic block's section ID equal to its number (basic block
267  // id). This further ensures that basic blocks are ordered canonically.
268  MBB.setSectionID({static_cast<unsigned int>(MBB.getNumber())});
269  } else if (FuncBBClusterInfo[MBB.getNumber()].hasValue())
270  MBB.setSectionID(FuncBBClusterInfo[MBB.getNumber()]->ClusterID);
271  else {
272  // BB goes into the special cold section if it is not specified in the
273  // cluster info map.
275  }
276 
277  if (MBB.isEHPad() && EHPadsSectionID != MBB.getSectionID() &&
278  EHPadsSectionID != MBBSectionID::ExceptionSectionID) {
279  // If we already have one cluster containing eh_pads, this must be updated
280  // to ExceptionSectionID. Otherwise, we set it equal to the current
281  // section ID.
282  EHPadsSectionID = EHPadsSectionID.hasValue()
284  : MBB.getSectionID();
285  }
286  }
287 
288  // If EHPads are in more than one section, this places all of them in the
289  // special exception section.
290  if (EHPadsSectionID == MBBSectionID::ExceptionSectionID)
291  for (auto &MBB : MF)
292  if (MBB.isEHPad())
293  MBB.setSectionID(EHPadsSectionID.getValue());
294 }
295 
299  MF.getNumBlockIDs());
300  for (auto &MBB : MF)
302 
303  MF.sort(MBBCmp);
304 
305  // Set IsBeginSection and IsEndSection according to the assigned section IDs.
306  MF.assignBeginEndSections();
307 
308  // After reordering basic blocks, we must update basic block branches to
309  // insert explicit fallthrough branches when required and optimize branches
310  // when possible.
311  updateBranches(MF, PreLayoutFallThroughs);
312 }
313 
314 // If the exception section begins with a landing pad, that landing pad will
315 // assume a zero offset (relative to @LPStart) in the LSDA. However, a value of
316 // zero implies "no landing pad." This function inserts a NOP just before the EH
317 // pad label to ensure a nonzero offset. Returns true if padding is not needed.
319  for (auto &MBB : MF) {
320  if (MBB.isBeginSection() && MBB.isEHPad()) {
322  while (!MI->isEHLabel())
323  ++MI;
324  MCInst Nop = MF.getSubtarget().getInstrInfo()->getNop();
325  BuildMI(MBB, MI, DebugLoc(),
326  MF.getSubtarget().getInstrInfo()->get(Nop.getOpcode()));
327  return false;
328  }
329  }
330  return true;
331 }
332 
333 // This checks if the source of this function has drifted since this binary was
334 // profiled previously. For now, we are piggy backing on what PGO does to
335 // detect this with instrumented profiles. PGO emits an hash of the IR and
336 // checks if the hash has changed. Advanced basic block layout is usually done
337 // on top of PGO optimized binaries and hence this check works well in practice.
340  return false;
341 
342  const char MetadataName[] = "instr_prof_hash_mismatch";
343  auto *Existing = MF.getFunction().getMetadata(LLVMContext::MD_annotation);
344  if (Existing) {
345  MDTuple *Tuple = cast<MDTuple>(Existing);
346  for (auto &N : Tuple->operands())
347  if (cast<MDString>(N.get())->getString() == MetadataName)
348  return true;
349  }
350 
351  return false;
352 }
353 
354 bool BasicBlockSections::runOnMachineFunction(MachineFunction &MF) {
355  auto BBSectionsType = MF.getTarget().getBBSectionsType();
356  assert(BBSectionsType != BasicBlockSection::None &&
357  "BB Sections not enabled!");
358 
359  // Check for source drift. If the source has changed since the profiles
360  // were obtained, optimizing basic blocks might be sub-optimal.
361  // This only applies to BasicBlockSection::List as it creates
362  // clusters of basic blocks using basic block ids. Source drift can
363  // invalidate these groupings leading to sub-optimal code generation with
364  // regards to performance.
365  if (BBSectionsType == BasicBlockSection::List &&
367  return true;
368 
369  // Renumber blocks before sorting them for basic block sections. This is
370  // useful during sorting, basic blocks in the same section will retain the
371  // default order. This renumbering should also be done for basic block
372  // labels to match the profiles with the correct blocks.
373  MF.RenumberBlocks();
374 
375  if (BBSectionsType == BasicBlockSection::Labels) {
376  MF.setBBSectionsType(BBSectionsType);
377  return true;
378  }
379 
380  std::vector<Optional<BBClusterInfo>> FuncBBClusterInfo;
381  if (BBSectionsType == BasicBlockSection::List &&
382  !getBBClusterInfoForFunction(MF, FuncAliasMap, ProgramBBClusterInfo,
383  FuncBBClusterInfo))
384  return true;
385  MF.setBBSectionsType(BBSectionsType);
386  assignSections(MF, FuncBBClusterInfo);
387 
388  // We make sure that the cluster including the entry basic block precedes all
389  // other clusters.
390  auto EntryBBSectionID = MF.front().getSectionID();
391 
392  // Helper function for ordering BB sections as follows:
393  // * Entry section (section including the entry block).
394  // * Regular sections (in increasing order of their Number).
395  // ...
396  // * Exception section
397  // * Cold section
398  auto MBBSectionOrder = [EntryBBSectionID](const MBBSectionID &LHS,
399  const MBBSectionID &RHS) {
400  // We make sure that the section containing the entry block precedes all the
401  // other sections.
402  if (LHS == EntryBBSectionID || RHS == EntryBBSectionID)
403  return LHS == EntryBBSectionID;
404  return LHS.Type == RHS.Type ? LHS.Number < RHS.Number : LHS.Type < RHS.Type;
405  };
406 
407  // We sort all basic blocks to make sure the basic blocks of every cluster are
408  // contiguous and ordered accordingly. Furthermore, clusters are ordered in
409  // increasing order of their section IDs, with the exception and the
410  // cold section placed at the end of the function.
411  auto Comparator = [&](const MachineBasicBlock &X,
412  const MachineBasicBlock &Y) {
413  auto XSectionID = X.getSectionID();
414  auto YSectionID = Y.getSectionID();
415  if (XSectionID != YSectionID)
416  return MBBSectionOrder(XSectionID, YSectionID);
417  // If the two basic block are in the same section, the order is decided by
418  // their position within the section.
419  if (XSectionID.Type == MBBSectionID::SectionType::Default)
420  return FuncBBClusterInfo[X.getNumber()]->PositionInCluster <
421  FuncBBClusterInfo[Y.getNumber()]->PositionInCluster;
422  return X.getNumber() < Y.getNumber();
423  };
424 
425  sortBasicBlocksAndUpdateBranches(MF, Comparator);
427  return true;
428 }
429 
430 // Basic Block Sections can be enabled for a subset of machine basic blocks.
431 // This is done by passing a file containing names of functions for which basic
432 // block sections are desired. Additionally, machine basic block ids of the
433 // functions can also be specified for a finer granularity. Moreover, a cluster
434 // of basic blocks could be assigned to the same section.
435 // A file with basic block sections for all of function main and three blocks
436 // for function foo (of which 1 and 2 are placed in a cluster) looks like this:
437 // ----------------------------
438 // list.txt:
439 // !main
440 // !foo
441 // !!1 2
442 // !!4
444  ProgramBBClusterInfoMapTy &ProgramBBClusterInfo,
445  StringMap<StringRef> &FuncAliasMap) {
446  assert(MBuf);
447  line_iterator LineIt(*MBuf, /*SkipBlanks=*/true, /*CommentMarker=*/'#');
448 
449  auto invalidProfileError = [&](auto Message) {
450  return make_error<StringError>(
451  Twine("Invalid profile " + MBuf->getBufferIdentifier() + " at line " +
452  Twine(LineIt.line_number()) + ": " + Message),
454  };
455 
456  auto FI = ProgramBBClusterInfo.end();
457 
458  // Current cluster ID corresponding to this function.
459  unsigned CurrentCluster = 0;
460  // Current position in the current cluster.
461  unsigned CurrentPosition = 0;
462 
463  // Temporary set to ensure every basic block ID appears once in the clusters
464  // of a function.
465  SmallSet<unsigned, 4> FuncBBIDs;
466 
467  for (; !LineIt.is_at_eof(); ++LineIt) {
468  StringRef S(*LineIt);
469  if (S[0] == '@')
470  continue;
471  // Check for the leading "!"
472  if (!S.consume_front("!") || S.empty())
473  break;
474  // Check for second "!" which indicates a cluster of basic blocks.
475  if (S.consume_front("!")) {
476  if (FI == ProgramBBClusterInfo.end())
477  return invalidProfileError(
478  "Cluster list does not follow a function name specifier.");
479  SmallVector<StringRef, 4> BBIndexes;
480  S.split(BBIndexes, ' ');
481  // Reset current cluster position.
482  CurrentPosition = 0;
483  for (auto BBIndexStr : BBIndexes) {
484  unsigned long long BBIndex;
485  if (getAsUnsignedInteger(BBIndexStr, 10, BBIndex))
486  return invalidProfileError(Twine("Unsigned integer expected: '") +
487  BBIndexStr + "'.");
488  if (!FuncBBIDs.insert(BBIndex).second)
489  return invalidProfileError(Twine("Duplicate basic block id found '") +
490  BBIndexStr + "'.");
491  if (!BBIndex && CurrentPosition)
492  return invalidProfileError("Entry BB (0) does not begin a cluster.");
493 
494  FI->second.emplace_back(BBClusterInfo{
495  ((unsigned)BBIndex), CurrentCluster, CurrentPosition++});
496  }
497  CurrentCluster++;
498  } else { // This is a function name specifier.
499  // Function aliases are separated using '/'. We use the first function
500  // name for the cluster info mapping and delegate all other aliases to
501  // this one.
503  S.split(Aliases, '/');
504  for (size_t i = 1; i < Aliases.size(); ++i)
505  FuncAliasMap.try_emplace(Aliases[i], Aliases.front());
506 
507  // Prepare for parsing clusters of this function name.
508  // Start a new cluster map for this function name.
509  FI = ProgramBBClusterInfo.try_emplace(Aliases.front()).first;
510  CurrentCluster = 0;
511  FuncBBIDs.clear();
512  }
513  }
514  return Error::success();
515 }
516 
517 bool BasicBlockSections::doInitialization(Module &M) {
518  if (!MBuf)
519  return false;
520  if (auto Err = getBBClusterInfo(MBuf, ProgramBBClusterInfo, FuncAliasMap))
522  return false;
523 }
524 
525 void BasicBlockSections::getAnalysisUsage(AnalysisUsage &AU) const {
526  AU.setPreservesAll();
528 }
529 
532  return new BasicBlockSections(Buf);
533 }
i
i
Definition: README.txt:29
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Definition: IRTranslator.cpp:105
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Definition: AllocatorList.h:23
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Definition: BasicBlockSections.cpp:296
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static const unsigned Nop
Instruction opcodes emitted via means other than CodeGen.
Definition: WebAssemblyMCTargetDesc.h:136
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A forward iterator which reads text lines from a buffer.
Definition: LineIterator.h:33
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cl::opt< std::string > BBSectionsColdTextPrefix
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This currently compiles esp xmm0 movsd esp eax eax esp ret We should use not the dag combiner This is because dagcombine2 needs to be able to see through the X86ISD::Wrapper which DAGCombine can t really do The code for turning x load into a single vector load is target independent and should be moved to the dag combiner The code for turning x load into a vector load can only handle a direct load from a global or a direct load from the stack It should be generalized to handle any load from P
Definition: README-SSE.txt:411
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bool analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB, MachineBasicBlock *&FBB, SmallVectorImpl< MachineOperand > &Cond, bool AllowModify) const override
Analyze the branching code at the end of MBB, returning true if it cannot be understood (e....
Definition: HexagonInstrInfo.cpp:389
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static bool getBBClusterInfoForFunction(const MachineFunction &MF, const StringMap< StringRef > FuncAliasMap, const ProgramBBClusterInfoMapTy &ProgramBBClusterInfo, std::vector< Optional< BBClusterInfo >> &V)
Definition: BasicBlockSections.cpp:209
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Definition: SmallVector.h:1168
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static ErrorSuccess success()
Create a success value.
Definition: Error.h:331
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MDNode * getMetadata(unsigned KindID) const
Get the current metadata attachments for the given kind, if any.
Definition: Metadata.cpp:1197
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Definition: MachineFunctionPass.h:30
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Definition: BasicBlockSections.cpp:318
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Definition: CommandLine.h:143
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unsigned getNumBlockIDs() const
getNumBlockIDs - Return the number of MBB ID's allocated.
Definition: MachineFunction.h:761
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Definition: StringMap.h:203
TargetInstrInfo.h
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unsigned Number
Definition: MachineBasicBlock.h:59
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Definition: SmallSet.h:134
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Definition: APInt.h:33
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Definition: BasicBlockSections.cpp:443
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Instances of this class represent a single low-level machine instruction.
Definition: MCInst.h:184
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Definition: StringMap.h:216
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Definition: MachineBasicBlock.h:52
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Definition: MemoryBuffer.h:50
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Definition: MachineBasicBlock.h:564
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Definition: Optional.h:288
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Sets the section ID for this basic block.
Definition: MachineBasicBlock.h:583
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Definition: MachineFunction.h:828
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Definition: SmallVector.h:1095
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Definition: TargetInstrInfo.h:97
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static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
Definition: PassRegistry.cpp:31
llvm::getAsUnsignedInteger
bool getAsUnsignedInteger(StringRef Str, unsigned Radix, unsigned long long &Result)
Helper functions for StringRef::getAsInteger.
Definition: StringRef.cpp:485
Y
static GCMetadataPrinterRegistry::Add< OcamlGCMetadataPrinter > Y("ocaml", "ocaml 3.10-compatible collector")
llvm::AnalysisUsage
Represent the analysis usage information of a pass.
Definition: PassAnalysisSupport.h:47
llvm::MDTuple
Tuple of metadata.
Definition: Metadata.h:1174
TII
const HexagonInstrInfo * TII
Definition: HexagonCopyToCombine.cpp:129
llvm::BasicBlockSection::Labels
@ Labels
INITIALIZE_PASS
INITIALIZE_PASS(BasicBlockSections, "bbsections-prepare", "Prepares for basic block sections, by splitting functions " "into clusters of basic blocks.", false, false) static void updateBranches(MachineFunction &MF
LineIterator.h
llvm::report_fatal_error
void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:143
llvm::BasicBlockSection::All
@ All
StringMap.h
X
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
llvm::MachineBasicBlock
Definition: MachineBasicBlock.h:95
llvm::StringMap
StringMap - This is an unconventional map that is specialized for handling keys that are "strings",...
Definition: StringMap.h:108
llvm::MemoryBuffer::getBufferIdentifier
virtual StringRef getBufferIdentifier() const
Return an identifier for this buffer, typically the filename it was read from.
Definition: MemoryBuffer.h:75
Passes.h
llvm::function_ref
An efficient, type-erasing, non-owning reference to a callable.
Definition: STLExtras.h:168
llvm::cl::opt
Definition: CommandLine.h:1432
const
aarch64 promote const
Definition: AArch64PromoteConstant.cpp:232
move
compiles ldr LCPI1_0 ldr ldr mov lsr tst moveq r1 ldr LCPI1_1 and r0 bx lr It would be better to do something like to fold the shift into the conditional move
Definition: README.txt:546
BasicBlockSectionUtils.h
llvm::cl::init
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:441
MachineFunctionPass.h
llvm::MachineFunction::getName
StringRef getName() const
getName - Return the name of the corresponding LLVM function.
Definition: MachineFunction.cpp:542
llvm::MBBSectionID::ExceptionSectionID
const static MBBSectionID ExceptionSectionID
Definition: MachineBasicBlock.h:65
assert
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
MachineModuleInfo.h
llvm::Module
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:67
llvm::MachineFunction
Definition: MachineFunction.h:234
llvm::MachineBasicBlock::getNumber
int getNumber() const
MachineBasicBlocks are uniquely numbered at the function level, unless they're not in a MachineFuncti...
Definition: MachineBasicBlock.h:1056
Cond
SmallVector< MachineOperand, 4 > Cond
Definition: BasicBlockSections.cpp:179
llvm::MachineBasicBlock::isEHPad
bool isEHPad() const
Returns true if the block is a landing pad.
Definition: MachineBasicBlock.h:526
llvm::StringRef
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:57
llvm::MachineBasicBlock::findBranchDebugLoc
DebugLoc findBranchDebugLoc()
Find and return the merged DebugLoc of the branch instructions of the block.
Definition: MachineBasicBlock.cpp:1414
llvm::MBBSectionID::Type
enum llvm::MBBSectionID::SectionType Type
llvm::ilist_node_impl::getIterator
self_iterator getIterator()
Definition: ilist_node.h:81
S
add sub stmia L5 ldr r0 bl L_printf $stub Instead of a and a wouldn t it be better to do three moves *Return an aggregate type is even return S
Definition: README.txt:210
llvm::MachineFunction::hasBBSections
bool hasBBSections() const
Returns true if this function has basic block sections enabled.
Definition: MachineFunction.h:612
llvm::initializeBasicBlockSectionsPass
void initializeBasicBlockSectionsPass(PassRegistry &)
llvm::SmallSet::insert
std::pair< NoneType, bool > insert(const T &V)
insert - Insert an element into the set if it isn't already there.
Definition: SmallSet.h:180
llvm::MachineBasicBlock::getSectionID
MBBSectionID getSectionID() const
Returns the section ID of this basic block.
Definition: MachineBasicBlock.h:574
MBB
MachineBasicBlock & MBB
Definition: AArch64SLSHardening.cpp:74
llvm::Twine
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:83
hasInstrProfHashMismatch
static bool hasInstrProfHashMismatch(MachineFunction &MF)
Definition: BasicBlockSections.cpp:338
llvm::MachineFunction::getFunction
Function & getFunction()
Return the LLVM function that this machine code represents.
Definition: MachineFunction.h:600
llvm::inconvertibleErrorCode
std::error_code inconvertibleErrorCode()
The value returned by this function can be returned from convertToErrorCode for Error values where no...
Definition: Error.cpp:77
llvm::AnalysisUsage::setPreservesAll
void setPreservesAll()
Set by analyses that do not transform their input at all.
Definition: PassAnalysisSupport.h:130
llvm::MachineFunction::getTarget
const LLVMTargetMachine & getTarget() const
getTarget - Return the target machine this machine code is compiled with
Definition: MachineFunction.h:630
llvm::MachineBasicBlock::isEndSection
bool isEndSection() const
Returns true if this block ends any section.
Definition: MachineBasicBlock.h:567
llvm::MBBSectionID::ColdSectionID
const static MBBSectionID ColdSectionID
Definition: MachineBasicBlock.h:64
BBSectionsDetectSourceDrift
cl::opt< bool > BBSectionsDetectSourceDrift("bbsections-detect-source-drift", cl::desc("This checks if there is a fdo instr. profile hash " "mismatch for this function"), cl::init(true), cl::Hidden)
llvm::createBasicBlockSectionsPass
MachineFunctionPass * createBasicBlockSectionsPass(const MemoryBuffer *Buf)
createBasicBlockSections Pass - This pass assigns sections to machine basic blocks and is enabled wit...
Definition: BasicBlockSections.cpp:531
llvm::Error
Lightweight error class with error context and mandatory checking.
Definition: Error.h:157
llvm::TargetStackID::Default
@ Default
Definition: TargetFrameLowering.h:28
llvm::line_iterator::is_at_eof
bool is_at_eof() const
Return true if we've reached EOF or are an "end" iterator.
Definition: LineIterator.h:60
llvm::MachineBasicBlock::getFallThrough
MachineBasicBlock * getFallThrough()
Return the fallthrough block if the block can implicitly transfer control to the block after it by fa...
Definition: MachineBasicBlock.cpp:921
llvm::line_iterator::line_number
int64_t line_number() const
Return the current line number. May return any number at EOF.
Definition: LineIterator.h:66
SmallVector.h
PreLayoutFallThroughs
const SmallVector< MachineBasicBlock *, 4 > & PreLayoutFallThroughs
Definition: BasicBlockSections.cpp:177
llvm::MachineBasicBlock::begin
iterator begin()
Definition: MachineBasicBlock.h:268
assignSections
static void assignSections(MachineFunction &MF, const std::vector< Optional< BBClusterInfo >> &FuncBBClusterInfo)
Definition: BasicBlockSections.cpp:250
llvm::BuildMI
MachineInstrBuilder BuildMI(MachineFunction &MF, const DebugLoc &DL, const MCInstrDesc &MCID)
Builder interface. Specify how to create the initial instruction itself.
Definition: MachineInstrBuilder.h:328
N
#define N
llvm::SmallSet::clear
void clear()
Definition: SmallSet.h:218
llvm::DebugLoc
A debug info location.
Definition: DebugLoc.h:33
llvm::cl::desc
Definition: CommandLine.h:412
llvm::MachineBasicBlock::updateTerminator
void updateTerminator(MachineBasicBlock *PreviousLayoutSuccessor)
Update the terminator instructions in block to account for changes to block layout which may have bee...
Definition: MachineBasicBlock.cpp:645
MachineFunction.h
llvm::MachineInstrBundleIterator< MachineInstr >
llvm::MachineFunction::setBBSectionsType
void setBBSectionsType(BasicBlockSection V)
Definition: MachineFunction.h:623
InitializePasses.h
llvm::MachineFunction::RenumberBlocks
void RenumberBlocks(MachineBasicBlock *MBBFrom=nullptr)
RenumberBlocks - This discards all of the MachineBasicBlock numbers and recomputes them.
Definition: MachineFunction.cpp:295
llvm::StringMap::try_emplace
std::pair< iterator, bool > try_emplace(StringRef Key, ArgsTy &&... Args)
Emplace a new element for the specified key into the map if the key isn't already in the map.
Definition: StringMap.h:328
llvm::Optional::getValue
constexpr const T & getValue() const LLVM_LVALUE_FUNCTION
Definition: Optional.h:282
llvm::TargetMachine::getBBSectionsType
llvm::BasicBlockSection getBBSectionsType() const
If basic blocks should be emitted into their own section, corresponding to -fbasic-block-sections.
Definition: TargetMachine.h:298
SmallSet.h
llvm::Intrinsic::ID
unsigned ID
Definition: TargetTransformInfo.h:38