LLVM  3.7.0
MergeFunctions.cpp
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1 //===- MergeFunctions.cpp - Merge identical functions ---------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This pass looks for equivalent functions that are mergable and folds them.
11 //
12 // Order relation is defined on set of functions. It was made through
13 // special function comparison procedure that returns
14 // 0 when functions are equal,
15 // -1 when Left function is less than right function, and
16 // 1 for opposite case. We need total-ordering, so we need to maintain
17 // four properties on the functions set:
18 // a <= a (reflexivity)
19 // if a <= b and b <= a then a = b (antisymmetry)
20 // if a <= b and b <= c then a <= c (transitivity).
21 // for all a and b: a <= b or b <= a (totality).
22 //
23 // Comparison iterates through each instruction in each basic block.
24 // Functions are kept on binary tree. For each new function F we perform
25 // lookup in binary tree.
26 // In practice it works the following way:
27 // -- We define Function* container class with custom "operator<" (FunctionPtr).
28 // -- "FunctionPtr" instances are stored in std::set collection, so every
29 // std::set::insert operation will give you result in log(N) time.
30 //
31 // When a match is found the functions are folded. If both functions are
32 // overridable, we move the functionality into a new internal function and
33 // leave two overridable thunks to it.
34 //
35 //===----------------------------------------------------------------------===//
36 //
37 // Future work:
38 //
39 // * virtual functions.
40 //
41 // Many functions have their address taken by the virtual function table for
42 // the object they belong to. However, as long as it's only used for a lookup
43 // and call, this is irrelevant, and we'd like to fold such functions.
44 //
45 // * be smarter about bitcasts.
46 //
47 // In order to fold functions, we will sometimes add either bitcast instructions
48 // or bitcast constant expressions. Unfortunately, this can confound further
49 // analysis since the two functions differ where one has a bitcast and the
50 // other doesn't. We should learn to look through bitcasts.
51 //
52 // * Compare complex types with pointer types inside.
53 // * Compare cross-reference cases.
54 // * Compare complex expressions.
55 //
56 // All the three issues above could be described as ability to prove that
57 // fA == fB == fC == fE == fF == fG in example below:
58 //
59 // void fA() {
60 // fB();
61 // }
62 // void fB() {
63 // fA();
64 // }
65 //
66 // void fE() {
67 // fF();
68 // }
69 // void fF() {
70 // fG();
71 // }
72 // void fG() {
73 // fE();
74 // }
75 //
76 // Simplest cross-reference case (fA <--> fB) was implemented in previous
77 // versions of MergeFunctions, though it presented only in two function pairs
78 // in test-suite (that counts >50k functions)
79 // Though possibility to detect complex cross-referencing (e.g.: A->B->C->D->A)
80 // could cover much more cases.
81 //
82 //===----------------------------------------------------------------------===//
83 
84 #include "llvm/Transforms/IPO.h"
85 #include "llvm/ADT/DenseSet.h"
86 #include "llvm/ADT/FoldingSet.h"
87 #include "llvm/ADT/STLExtras.h"
88 #include "llvm/ADT/SmallSet.h"
89 #include "llvm/ADT/Statistic.h"
90 #include "llvm/IR/CallSite.h"
91 #include "llvm/IR/Constants.h"
92 #include "llvm/IR/DataLayout.h"
93 #include "llvm/IR/IRBuilder.h"
94 #include "llvm/IR/InlineAsm.h"
95 #include "llvm/IR/Instructions.h"
96 #include "llvm/IR/LLVMContext.h"
97 #include "llvm/IR/Module.h"
98 #include "llvm/IR/Operator.h"
99 #include "llvm/IR/ValueHandle.h"
100 #include "llvm/Pass.h"
102 #include "llvm/Support/Debug.h"
105 #include <vector>
106 using namespace llvm;
107 
108 #define DEBUG_TYPE "mergefunc"
109 
110 STATISTIC(NumFunctionsMerged, "Number of functions merged");
111 STATISTIC(NumThunksWritten, "Number of thunks generated");
112 STATISTIC(NumAliasesWritten, "Number of aliases generated");
113 STATISTIC(NumDoubleWeak, "Number of new functions created");
114 
116  "mergefunc-sanity",
117  cl::desc("How many functions in module could be used for "
118  "MergeFunctions pass sanity check. "
119  "'0' disables this check. Works only with '-debug' key."),
120  cl::init(0), cl::Hidden);
121 
122 namespace {
123 
124 /// FunctionComparator - Compares two functions to determine whether or not
125 /// they will generate machine code with the same behaviour. DataLayout is
126 /// used if available. The comparator always fails conservatively (erring on the
127 /// side of claiming that two functions are different).
128 class FunctionComparator {
129 public:
130  FunctionComparator(const Function *F1, const Function *F2)
131  : FnL(F1), FnR(F2) {}
132 
133  /// Test whether the two functions have equivalent behaviour.
134  int compare();
135 
136 private:
137  /// Test whether two basic blocks have equivalent behaviour.
138  int compare(const BasicBlock *BBL, const BasicBlock *BBR);
139 
140  /// Constants comparison.
141  /// Its analog to lexicographical comparison between hypothetical numbers
142  /// of next format:
143  /// <bitcastability-trait><raw-bit-contents>
144  ///
145  /// 1. Bitcastability.
146  /// Check whether L's type could be losslessly bitcasted to R's type.
147  /// On this stage method, in case when lossless bitcast is not possible
148  /// method returns -1 or 1, thus also defining which type is greater in
149  /// context of bitcastability.
150  /// Stage 0: If types are equal in terms of cmpTypes, then we can go straight
151  /// to the contents comparison.
152  /// If types differ, remember types comparison result and check
153  /// whether we still can bitcast types.
154  /// Stage 1: Types that satisfies isFirstClassType conditions are always
155  /// greater then others.
156  /// Stage 2: Vector is greater then non-vector.
157  /// If both types are vectors, then vector with greater bitwidth is
158  /// greater.
159  /// If both types are vectors with the same bitwidth, then types
160  /// are bitcastable, and we can skip other stages, and go to contents
161  /// comparison.
162  /// Stage 3: Pointer types are greater than non-pointers. If both types are
163  /// pointers of the same address space - go to contents comparison.
164  /// Different address spaces: pointer with greater address space is
165  /// greater.
166  /// Stage 4: Types are neither vectors, nor pointers. And they differ.
167  /// We don't know how to bitcast them. So, we better don't do it,
168  /// and return types comparison result (so it determines the
169  /// relationship among constants we don't know how to bitcast).
170  ///
171  /// Just for clearance, let's see how the set of constants could look
172  /// on single dimension axis:
173  ///
174  /// [NFCT], [FCT, "others"], [FCT, pointers], [FCT, vectors]
175  /// Where: NFCT - Not a FirstClassType
176  /// FCT - FirstClassTyp:
177  ///
178  /// 2. Compare raw contents.
179  /// It ignores types on this stage and only compares bits from L and R.
180  /// Returns 0, if L and R has equivalent contents.
181  /// -1 or 1 if values are different.
182  /// Pretty trivial:
183  /// 2.1. If contents are numbers, compare numbers.
184  /// Ints with greater bitwidth are greater. Ints with same bitwidths
185  /// compared by their contents.
186  /// 2.2. "And so on". Just to avoid discrepancies with comments
187  /// perhaps it would be better to read the implementation itself.
188  /// 3. And again about overall picture. Let's look back at how the ordered set
189  /// of constants will look like:
190  /// [NFCT], [FCT, "others"], [FCT, pointers], [FCT, vectors]
191  ///
192  /// Now look, what could be inside [FCT, "others"], for example:
193  /// [FCT, "others"] =
194  /// [
195  /// [double 0.1], [double 1.23],
196  /// [i32 1], [i32 2],
197  /// { double 1.0 }, ; StructTyID, NumElements = 1
198  /// { i32 1 }, ; StructTyID, NumElements = 1
199  /// { double 1, i32 1 }, ; StructTyID, NumElements = 2
200  /// { i32 1, double 1 } ; StructTyID, NumElements = 2
201  /// ]
202  ///
203  /// Let's explain the order. Float numbers will be less than integers, just
204  /// because of cmpType terms: FloatTyID < IntegerTyID.
205  /// Floats (with same fltSemantics) are sorted according to their value.
206  /// Then you can see integers, and they are, like a floats,
207  /// could be easy sorted among each others.
208  /// The structures. Structures are grouped at the tail, again because of their
209  /// TypeID: StructTyID > IntegerTyID > FloatTyID.
210  /// Structures with greater number of elements are greater. Structures with
211  /// greater elements going first are greater.
212  /// The same logic with vectors, arrays and other possible complex types.
213  ///
214  /// Bitcastable constants.
215  /// Let's assume, that some constant, belongs to some group of
216  /// "so-called-equal" values with different types, and at the same time
217  /// belongs to another group of constants with equal types
218  /// and "really" equal values.
219  ///
220  /// Now, prove that this is impossible:
221  ///
222  /// If constant A with type TyA is bitcastable to B with type TyB, then:
223  /// 1. All constants with equal types to TyA, are bitcastable to B. Since
224  /// those should be vectors (if TyA is vector), pointers
225  /// (if TyA is pointer), or else (if TyA equal to TyB), those types should
226  /// be equal to TyB.
227  /// 2. All constants with non-equal, but bitcastable types to TyA, are
228  /// bitcastable to B.
229  /// Once again, just because we allow it to vectors and pointers only.
230  /// This statement could be expanded as below:
231  /// 2.1. All vectors with equal bitwidth to vector A, has equal bitwidth to
232  /// vector B, and thus bitcastable to B as well.
233  /// 2.2. All pointers of the same address space, no matter what they point to,
234  /// bitcastable. So if C is pointer, it could be bitcasted to A and to B.
235  /// So any constant equal or bitcastable to A is equal or bitcastable to B.
236  /// QED.
237  ///
238  /// In another words, for pointers and vectors, we ignore top-level type and
239  /// look at their particular properties (bit-width for vectors, and
240  /// address space for pointers).
241  /// If these properties are equal - compare their contents.
242  int cmpConstants(const Constant *L, const Constant *R);
243 
244  /// Assign or look up previously assigned numbers for the two values, and
245  /// return whether the numbers are equal. Numbers are assigned in the order
246  /// visited.
247  /// Comparison order:
248  /// Stage 0: Value that is function itself is always greater then others.
249  /// If left and right values are references to their functions, then
250  /// they are equal.
251  /// Stage 1: Constants are greater than non-constants.
252  /// If both left and right are constants, then the result of
253  /// cmpConstants is used as cmpValues result.
254  /// Stage 2: InlineAsm instances are greater than others. If both left and
255  /// right are InlineAsm instances, InlineAsm* pointers casted to
256  /// integers and compared as numbers.
257  /// Stage 3: For all other cases we compare order we meet these values in
258  /// their functions. If right value was met first during scanning,
259  /// then left value is greater.
260  /// In another words, we compare serial numbers, for more details
261  /// see comments for sn_mapL and sn_mapR.
262  int cmpValues(const Value *L, const Value *R);
263 
264  /// Compare two Instructions for equivalence, similar to
265  /// Instruction::isSameOperationAs but with modifications to the type
266  /// comparison.
267  /// Stages are listed in "most significant stage first" order:
268  /// On each stage below, we do comparison between some left and right
269  /// operation parts. If parts are non-equal, we assign parts comparison
270  /// result to the operation comparison result and exit from method.
271  /// Otherwise we proceed to the next stage.
272  /// Stages:
273  /// 1. Operations opcodes. Compared as numbers.
274  /// 2. Number of operands.
275  /// 3. Operation types. Compared with cmpType method.
276  /// 4. Compare operation subclass optional data as stream of bytes:
277  /// just convert it to integers and call cmpNumbers.
278  /// 5. Compare in operation operand types with cmpType in
279  /// most significant operand first order.
280  /// 6. Last stage. Check operations for some specific attributes.
281  /// For example, for Load it would be:
282  /// 6.1.Load: volatile (as boolean flag)
283  /// 6.2.Load: alignment (as integer numbers)
284  /// 6.3.Load: synch-scope (as integer numbers)
285  /// 6.4.Load: range metadata (as integer numbers)
286  /// On this stage its better to see the code, since its not more than 10-15
287  /// strings for particular instruction, and could change sometimes.
288  int cmpOperations(const Instruction *L, const Instruction *R) const;
289 
290  /// Compare two GEPs for equivalent pointer arithmetic.
291  /// Parts to be compared for each comparison stage,
292  /// most significant stage first:
293  /// 1. Address space. As numbers.
294  /// 2. Constant offset, (using GEPOperator::accumulateConstantOffset method).
295  /// 3. Pointer operand type (using cmpType method).
296  /// 4. Number of operands.
297  /// 5. Compare operands, using cmpValues method.
298  int cmpGEPs(const GEPOperator *GEPL, const GEPOperator *GEPR);
299  int cmpGEPs(const GetElementPtrInst *GEPL, const GetElementPtrInst *GEPR) {
300  return cmpGEPs(cast<GEPOperator>(GEPL), cast<GEPOperator>(GEPR));
301  }
302 
303  /// cmpType - compares two types,
304  /// defines total ordering among the types set.
305  ///
306  /// Return values:
307  /// 0 if types are equal,
308  /// -1 if Left is less than Right,
309  /// +1 if Left is greater than Right.
310  ///
311  /// Description:
312  /// Comparison is broken onto stages. Like in lexicographical comparison
313  /// stage coming first has higher priority.
314  /// On each explanation stage keep in mind total ordering properties.
315  ///
316  /// 0. Before comparison we coerce pointer types of 0 address space to
317  /// integer.
318  /// We also don't bother with same type at left and right, so
319  /// just return 0 in this case.
320  ///
321  /// 1. If types are of different kind (different type IDs).
322  /// Return result of type IDs comparison, treating them as numbers.
323  /// 2. If types are vectors or integers, compare Type* values as numbers.
324  /// 3. Types has same ID, so check whether they belongs to the next group:
325  /// * Void
326  /// * Float
327  /// * Double
328  /// * X86_FP80
329  /// * FP128
330  /// * PPC_FP128
331  /// * Label
332  /// * Metadata
333  /// If so - return 0, yes - we can treat these types as equal only because
334  /// their IDs are same.
335  /// 4. If Left and Right are pointers, return result of address space
336  /// comparison (numbers comparison). We can treat pointer types of same
337  /// address space as equal.
338  /// 5. If types are complex.
339  /// Then both Left and Right are to be expanded and their element types will
340  /// be checked with the same way. If we get Res != 0 on some stage, return it.
341  /// Otherwise return 0.
342  /// 6. For all other cases put llvm_unreachable.
343  int cmpTypes(Type *TyL, Type *TyR) const;
344 
345  int cmpNumbers(uint64_t L, uint64_t R) const;
346 
347  int cmpAPInts(const APInt &L, const APInt &R) const;
348  int cmpAPFloats(const APFloat &L, const APFloat &R) const;
349  int cmpStrings(StringRef L, StringRef R) const;
350  int cmpAttrs(const AttributeSet L, const AttributeSet R) const;
351 
352  // The two functions undergoing comparison.
353  const Function *FnL, *FnR;
354 
355  /// Assign serial numbers to values from left function, and values from
356  /// right function.
357  /// Explanation:
358  /// Being comparing functions we need to compare values we meet at left and
359  /// right sides.
360  /// Its easy to sort things out for external values. It just should be
361  /// the same value at left and right.
362  /// But for local values (those were introduced inside function body)
363  /// we have to ensure they were introduced at exactly the same place,
364  /// and plays the same role.
365  /// Let's assign serial number to each value when we meet it first time.
366  /// Values that were met at same place will be with same serial numbers.
367  /// In this case it would be good to explain few points about values assigned
368  /// to BBs and other ways of implementation (see below).
369  ///
370  /// 1. Safety of BB reordering.
371  /// It's safe to change the order of BasicBlocks in function.
372  /// Relationship with other functions and serial numbering will not be
373  /// changed in this case.
374  /// As follows from FunctionComparator::compare(), we do CFG walk: we start
375  /// from the entry, and then take each terminator. So it doesn't matter how in
376  /// fact BBs are ordered in function. And since cmpValues are called during
377  /// this walk, the numbering depends only on how BBs located inside the CFG.
378  /// So the answer is - yes. We will get the same numbering.
379  ///
380  /// 2. Impossibility to use dominance properties of values.
381  /// If we compare two instruction operands: first is usage of local
382  /// variable AL from function FL, and second is usage of local variable AR
383  /// from FR, we could compare their origins and check whether they are
384  /// defined at the same place.
385  /// But, we are still not able to compare operands of PHI nodes, since those
386  /// could be operands from further BBs we didn't scan yet.
387  /// So it's impossible to use dominance properties in general.
388  DenseMap<const Value*, int> sn_mapL, sn_mapR;
389 };
390 
391 class FunctionNode {
392  mutable AssertingVH<Function> F;
393 
394 public:
395  FunctionNode(Function *F) : F(F) {}
396  Function *getFunc() const { return F; }
397 
398  /// Replace the reference to the function F by the function G, assuming their
399  /// implementations are equal.
400  void replaceBy(Function *G) const {
401  assert(!(*this < FunctionNode(G)) && !(FunctionNode(G) < *this) &&
402  "The two functions must be equal");
403 
404  F = G;
405  }
406 
407  void release() { F = 0; }
408  bool operator<(const FunctionNode &RHS) const {
409  return (FunctionComparator(F, RHS.getFunc()).compare()) == -1;
410  }
411 };
412 }
413 
414 int FunctionComparator::cmpNumbers(uint64_t L, uint64_t R) const {
415  if (L < R) return -1;
416  if (L > R) return 1;
417  return 0;
418 }
419 
420 int FunctionComparator::cmpAPInts(const APInt &L, const APInt &R) const {
421  if (int Res = cmpNumbers(L.getBitWidth(), R.getBitWidth()))
422  return Res;
423  if (L.ugt(R)) return 1;
424  if (R.ugt(L)) return -1;
425  return 0;
426 }
427 
428 int FunctionComparator::cmpAPFloats(const APFloat &L, const APFloat &R) const {
429  if (int Res = cmpNumbers((uint64_t)&L.getSemantics(),
430  (uint64_t)&R.getSemantics()))
431  return Res;
432  return cmpAPInts(L.bitcastToAPInt(), R.bitcastToAPInt());
433 }
434 
435 int FunctionComparator::cmpStrings(StringRef L, StringRef R) const {
436  // Prevent heavy comparison, compare sizes first.
437  if (int Res = cmpNumbers(L.size(), R.size()))
438  return Res;
439 
440  // Compare strings lexicographically only when it is necessary: only when
441  // strings are equal in size.
442  return L.compare(R);
443 }
444 
445 int FunctionComparator::cmpAttrs(const AttributeSet L,
446  const AttributeSet R) const {
447  if (int Res = cmpNumbers(L.getNumSlots(), R.getNumSlots()))
448  return Res;
449 
450  for (unsigned i = 0, e = L.getNumSlots(); i != e; ++i) {
451  AttributeSet::iterator LI = L.begin(i), LE = L.end(i), RI = R.begin(i),
452  RE = R.end(i);
453  for (; LI != LE && RI != RE; ++LI, ++RI) {
454  Attribute LA = *LI;
455  Attribute RA = *RI;
456  if (LA < RA)
457  return -1;
458  if (RA < LA)
459  return 1;
460  }
461  if (LI != LE)
462  return 1;
463  if (RI != RE)
464  return -1;
465  }
466  return 0;
467 }
468 
469 /// Constants comparison:
470 /// 1. Check whether type of L constant could be losslessly bitcasted to R
471 /// type.
472 /// 2. Compare constant contents.
473 /// For more details see declaration comments.
474 int FunctionComparator::cmpConstants(const Constant *L, const Constant *R) {
475 
476  Type *TyL = L->getType();
477  Type *TyR = R->getType();
478 
479  // Check whether types are bitcastable. This part is just re-factored
480  // Type::canLosslesslyBitCastTo method, but instead of returning true/false,
481  // we also pack into result which type is "less" for us.
482  int TypesRes = cmpTypes(TyL, TyR);
483  if (TypesRes != 0) {
484  // Types are different, but check whether we can bitcast them.
485  if (!TyL->isFirstClassType()) {
486  if (TyR->isFirstClassType())
487  return -1;
488  // Neither TyL nor TyR are values of first class type. Return the result
489  // of comparing the types
490  return TypesRes;
491  }
492  if (!TyR->isFirstClassType()) {
493  if (TyL->isFirstClassType())
494  return 1;
495  return TypesRes;
496  }
497 
498  // Vector -> Vector conversions are always lossless if the two vector types
499  // have the same size, otherwise not.
500  unsigned TyLWidth = 0;
501  unsigned TyRWidth = 0;
502 
503  if (const VectorType *VecTyL = dyn_cast<VectorType>(TyL))
504  TyLWidth = VecTyL->getBitWidth();
505  if (const VectorType *VecTyR = dyn_cast<VectorType>(TyR))
506  TyRWidth = VecTyR->getBitWidth();
507 
508  if (TyLWidth != TyRWidth)
509  return cmpNumbers(TyLWidth, TyRWidth);
510 
511  // Zero bit-width means neither TyL nor TyR are vectors.
512  if (!TyLWidth) {
513  PointerType *PTyL = dyn_cast<PointerType>(TyL);
514  PointerType *PTyR = dyn_cast<PointerType>(TyR);
515  if (PTyL && PTyR) {
516  unsigned AddrSpaceL = PTyL->getAddressSpace();
517  unsigned AddrSpaceR = PTyR->getAddressSpace();
518  if (int Res = cmpNumbers(AddrSpaceL, AddrSpaceR))
519  return Res;
520  }
521  if (PTyL)
522  return 1;
523  if (PTyR)
524  return -1;
525 
526  // TyL and TyR aren't vectors, nor pointers. We don't know how to
527  // bitcast them.
528  return TypesRes;
529  }
530  }
531 
532  // OK, types are bitcastable, now check constant contents.
533 
534  if (L->isNullValue() && R->isNullValue())
535  return TypesRes;
536  if (L->isNullValue() && !R->isNullValue())
537  return 1;
538  if (!L->isNullValue() && R->isNullValue())
539  return -1;
540 
541  if (int Res = cmpNumbers(L->getValueID(), R->getValueID()))
542  return Res;
543 
544  switch (L->getValueID()) {
545  case Value::UndefValueVal: return TypesRes;
546  case Value::ConstantIntVal: {
547  const APInt &LInt = cast<ConstantInt>(L)->getValue();
548  const APInt &RInt = cast<ConstantInt>(R)->getValue();
549  return cmpAPInts(LInt, RInt);
550  }
551  case Value::ConstantFPVal: {
552  const APFloat &LAPF = cast<ConstantFP>(L)->getValueAPF();
553  const APFloat &RAPF = cast<ConstantFP>(R)->getValueAPF();
554  return cmpAPFloats(LAPF, RAPF);
555  }
556  case Value::ConstantArrayVal: {
557  const ConstantArray *LA = cast<ConstantArray>(L);
558  const ConstantArray *RA = cast<ConstantArray>(R);
559  uint64_t NumElementsL = cast<ArrayType>(TyL)->getNumElements();
560  uint64_t NumElementsR = cast<ArrayType>(TyR)->getNumElements();
561  if (int Res = cmpNumbers(NumElementsL, NumElementsR))
562  return Res;
563  for (uint64_t i = 0; i < NumElementsL; ++i) {
564  if (int Res = cmpConstants(cast<Constant>(LA->getOperand(i)),
565  cast<Constant>(RA->getOperand(i))))
566  return Res;
567  }
568  return 0;
569  }
570  case Value::ConstantStructVal: {
571  const ConstantStruct *LS = cast<ConstantStruct>(L);
572  const ConstantStruct *RS = cast<ConstantStruct>(R);
573  unsigned NumElementsL = cast<StructType>(TyL)->getNumElements();
574  unsigned NumElementsR = cast<StructType>(TyR)->getNumElements();
575  if (int Res = cmpNumbers(NumElementsL, NumElementsR))
576  return Res;
577  for (unsigned i = 0; i != NumElementsL; ++i) {
578  if (int Res = cmpConstants(cast<Constant>(LS->getOperand(i)),
579  cast<Constant>(RS->getOperand(i))))
580  return Res;
581  }
582  return 0;
583  }
584  case Value::ConstantVectorVal: {
585  const ConstantVector *LV = cast<ConstantVector>(L);
586  const ConstantVector *RV = cast<ConstantVector>(R);
587  unsigned NumElementsL = cast<VectorType>(TyL)->getNumElements();
588  unsigned NumElementsR = cast<VectorType>(TyR)->getNumElements();
589  if (int Res = cmpNumbers(NumElementsL, NumElementsR))
590  return Res;
591  for (uint64_t i = 0; i < NumElementsL; ++i) {
592  if (int Res = cmpConstants(cast<Constant>(LV->getOperand(i)),
593  cast<Constant>(RV->getOperand(i))))
594  return Res;
595  }
596  return 0;
597  }
598  case Value::ConstantExprVal: {
599  const ConstantExpr *LE = cast<ConstantExpr>(L);
600  const ConstantExpr *RE = cast<ConstantExpr>(R);
601  unsigned NumOperandsL = LE->getNumOperands();
602  unsigned NumOperandsR = RE->getNumOperands();
603  if (int Res = cmpNumbers(NumOperandsL, NumOperandsR))
604  return Res;
605  for (unsigned i = 0; i < NumOperandsL; ++i) {
606  if (int Res = cmpConstants(cast<Constant>(LE->getOperand(i)),
607  cast<Constant>(RE->getOperand(i))))
608  return Res;
609  }
610  return 0;
611  }
612  case Value::FunctionVal:
613  case Value::GlobalVariableVal:
614  case Value::GlobalAliasVal:
615  default: // Unknown constant, cast L and R pointers to numbers and compare.
616  return cmpNumbers((uint64_t)L, (uint64_t)R);
617  }
618 }
619 
620 /// cmpType - compares two types,
621 /// defines total ordering among the types set.
622 /// See method declaration comments for more details.
623 int FunctionComparator::cmpTypes(Type *TyL, Type *TyR) const {
624 
625  PointerType *PTyL = dyn_cast<PointerType>(TyL);
626  PointerType *PTyR = dyn_cast<PointerType>(TyR);
627 
628  const DataLayout &DL = FnL->getParent()->getDataLayout();
629  if (PTyL && PTyL->getAddressSpace() == 0)
630  TyL = DL.getIntPtrType(TyL);
631  if (PTyR && PTyR->getAddressSpace() == 0)
632  TyR = DL.getIntPtrType(TyR);
633 
634  if (TyL == TyR)
635  return 0;
636 
637  if (int Res = cmpNumbers(TyL->getTypeID(), TyR->getTypeID()))
638  return Res;
639 
640  switch (TyL->getTypeID()) {
641  default:
642  llvm_unreachable("Unknown type!");
643  // Fall through in Release mode.
644  case Type::IntegerTyID:
645  case Type::VectorTyID:
646  // TyL == TyR would have returned true earlier.
647  return cmpNumbers((uint64_t)TyL, (uint64_t)TyR);
648 
649  case Type::VoidTyID:
650  case Type::FloatTyID:
651  case Type::DoubleTyID:
652  case Type::X86_FP80TyID:
653  case Type::FP128TyID:
654  case Type::PPC_FP128TyID:
655  case Type::LabelTyID:
656  case Type::MetadataTyID:
657  return 0;
658 
659  case Type::PointerTyID: {
660  assert(PTyL && PTyR && "Both types must be pointers here.");
661  return cmpNumbers(PTyL->getAddressSpace(), PTyR->getAddressSpace());
662  }
663 
664  case Type::StructTyID: {
665  StructType *STyL = cast<StructType>(TyL);
666  StructType *STyR = cast<StructType>(TyR);
667  if (STyL->getNumElements() != STyR->getNumElements())
668  return cmpNumbers(STyL->getNumElements(), STyR->getNumElements());
669 
670  if (STyL->isPacked() != STyR->isPacked())
671  return cmpNumbers(STyL->isPacked(), STyR->isPacked());
672 
673  for (unsigned i = 0, e = STyL->getNumElements(); i != e; ++i) {
674  if (int Res = cmpTypes(STyL->getElementType(i), STyR->getElementType(i)))
675  return Res;
676  }
677  return 0;
678  }
679 
680  case Type::FunctionTyID: {
681  FunctionType *FTyL = cast<FunctionType>(TyL);
682  FunctionType *FTyR = cast<FunctionType>(TyR);
683  if (FTyL->getNumParams() != FTyR->getNumParams())
684  return cmpNumbers(FTyL->getNumParams(), FTyR->getNumParams());
685 
686  if (FTyL->isVarArg() != FTyR->isVarArg())
687  return cmpNumbers(FTyL->isVarArg(), FTyR->isVarArg());
688 
689  if (int Res = cmpTypes(FTyL->getReturnType(), FTyR->getReturnType()))
690  return Res;
691 
692  for (unsigned i = 0, e = FTyL->getNumParams(); i != e; ++i) {
693  if (int Res = cmpTypes(FTyL->getParamType(i), FTyR->getParamType(i)))
694  return Res;
695  }
696  return 0;
697  }
698 
699  case Type::ArrayTyID: {
700  ArrayType *ATyL = cast<ArrayType>(TyL);
701  ArrayType *ATyR = cast<ArrayType>(TyR);
702  if (ATyL->getNumElements() != ATyR->getNumElements())
703  return cmpNumbers(ATyL->getNumElements(), ATyR->getNumElements());
704  return cmpTypes(ATyL->getElementType(), ATyR->getElementType());
705  }
706  }
707 }
708 
709 // Determine whether the two operations are the same except that pointer-to-A
710 // and pointer-to-B are equivalent. This should be kept in sync with
711 // Instruction::isSameOperationAs.
712 // Read method declaration comments for more details.
713 int FunctionComparator::cmpOperations(const Instruction *L,
714  const Instruction *R) const {
715  // Differences from Instruction::isSameOperationAs:
716  // * replace type comparison with calls to isEquivalentType.
717  // * we test for I->hasSameSubclassOptionalData (nuw/nsw/tail) at the top
718  // * because of the above, we don't test for the tail bit on calls later on
719  if (int Res = cmpNumbers(L->getOpcode(), R->getOpcode()))
720  return Res;
721 
722  if (int Res = cmpNumbers(L->getNumOperands(), R->getNumOperands()))
723  return Res;
724 
725  if (int Res = cmpTypes(L->getType(), R->getType()))
726  return Res;
727 
728  if (int Res = cmpNumbers(L->getRawSubclassOptionalData(),
730  return Res;
731 
732  if (const AllocaInst *AI = dyn_cast<AllocaInst>(L)) {
733  if (int Res = cmpTypes(AI->getAllocatedType(),
734  cast<AllocaInst>(R)->getAllocatedType()))
735  return Res;
736  if (int Res =
737  cmpNumbers(AI->getAlignment(), cast<AllocaInst>(R)->getAlignment()))
738  return Res;
739  }
740 
741  // We have two instructions of identical opcode and #operands. Check to see
742  // if all operands are the same type
743  for (unsigned i = 0, e = L->getNumOperands(); i != e; ++i) {
744  if (int Res =
745  cmpTypes(L->getOperand(i)->getType(), R->getOperand(i)->getType()))
746  return Res;
747  }
748 
749  // Check special state that is a part of some instructions.
750  if (const LoadInst *LI = dyn_cast<LoadInst>(L)) {
751  if (int Res = cmpNumbers(LI->isVolatile(), cast<LoadInst>(R)->isVolatile()))
752  return Res;
753  if (int Res =
754  cmpNumbers(LI->getAlignment(), cast<LoadInst>(R)->getAlignment()))
755  return Res;
756  if (int Res =
757  cmpNumbers(LI->getOrdering(), cast<LoadInst>(R)->getOrdering()))
758  return Res;
759  if (int Res =
760  cmpNumbers(LI->getSynchScope(), cast<LoadInst>(R)->getSynchScope()))
761  return Res;
762  return cmpNumbers((uint64_t)LI->getMetadata(LLVMContext::MD_range),
763  (uint64_t)cast<LoadInst>(R)->getMetadata(LLVMContext::MD_range));
764  }
765  if (const StoreInst *SI = dyn_cast<StoreInst>(L)) {
766  if (int Res =
767  cmpNumbers(SI->isVolatile(), cast<StoreInst>(R)->isVolatile()))
768  return Res;
769  if (int Res =
770  cmpNumbers(SI->getAlignment(), cast<StoreInst>(R)->getAlignment()))
771  return Res;
772  if (int Res =
773  cmpNumbers(SI->getOrdering(), cast<StoreInst>(R)->getOrdering()))
774  return Res;
775  return cmpNumbers(SI->getSynchScope(), cast<StoreInst>(R)->getSynchScope());
776  }
777  if (const CmpInst *CI = dyn_cast<CmpInst>(L))
778  return cmpNumbers(CI->getPredicate(), cast<CmpInst>(R)->getPredicate());
779  if (const CallInst *CI = dyn_cast<CallInst>(L)) {
780  if (int Res = cmpNumbers(CI->getCallingConv(),
781  cast<CallInst>(R)->getCallingConv()))
782  return Res;
783  if (int Res =
784  cmpAttrs(CI->getAttributes(), cast<CallInst>(R)->getAttributes()))
785  return Res;
786  return cmpNumbers(
787  (uint64_t)CI->getMetadata(LLVMContext::MD_range),
788  (uint64_t)cast<CallInst>(R)->getMetadata(LLVMContext::MD_range));
789  }
790  if (const InvokeInst *CI = dyn_cast<InvokeInst>(L)) {
791  if (int Res = cmpNumbers(CI->getCallingConv(),
792  cast<InvokeInst>(R)->getCallingConv()))
793  return Res;
794  if (int Res =
795  cmpAttrs(CI->getAttributes(), cast<InvokeInst>(R)->getAttributes()))
796  return Res;
797  return cmpNumbers(
798  (uint64_t)CI->getMetadata(LLVMContext::MD_range),
799  (uint64_t)cast<InvokeInst>(R)->getMetadata(LLVMContext::MD_range));
800  }
801  if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(L)) {
802  ArrayRef<unsigned> LIndices = IVI->getIndices();
803  ArrayRef<unsigned> RIndices = cast<InsertValueInst>(R)->getIndices();
804  if (int Res = cmpNumbers(LIndices.size(), RIndices.size()))
805  return Res;
806  for (size_t i = 0, e = LIndices.size(); i != e; ++i) {
807  if (int Res = cmpNumbers(LIndices[i], RIndices[i]))
808  return Res;
809  }
810  }
811  if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(L)) {
812  ArrayRef<unsigned> LIndices = EVI->getIndices();
813  ArrayRef<unsigned> RIndices = cast<ExtractValueInst>(R)->getIndices();
814  if (int Res = cmpNumbers(LIndices.size(), RIndices.size()))
815  return Res;
816  for (size_t i = 0, e = LIndices.size(); i != e; ++i) {
817  if (int Res = cmpNumbers(LIndices[i], RIndices[i]))
818  return Res;
819  }
820  }
821  if (const FenceInst *FI = dyn_cast<FenceInst>(L)) {
822  if (int Res =
823  cmpNumbers(FI->getOrdering(), cast<FenceInst>(R)->getOrdering()))
824  return Res;
825  return cmpNumbers(FI->getSynchScope(), cast<FenceInst>(R)->getSynchScope());
826  }
827 
828  if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(L)) {
829  if (int Res = cmpNumbers(CXI->isVolatile(),
830  cast<AtomicCmpXchgInst>(R)->isVolatile()))
831  return Res;
832  if (int Res = cmpNumbers(CXI->isWeak(),
833  cast<AtomicCmpXchgInst>(R)->isWeak()))
834  return Res;
835  if (int Res = cmpNumbers(CXI->getSuccessOrdering(),
836  cast<AtomicCmpXchgInst>(R)->getSuccessOrdering()))
837  return Res;
838  if (int Res = cmpNumbers(CXI->getFailureOrdering(),
839  cast<AtomicCmpXchgInst>(R)->getFailureOrdering()))
840  return Res;
841  return cmpNumbers(CXI->getSynchScope(),
842  cast<AtomicCmpXchgInst>(R)->getSynchScope());
843  }
844  if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(L)) {
845  if (int Res = cmpNumbers(RMWI->getOperation(),
846  cast<AtomicRMWInst>(R)->getOperation()))
847  return Res;
848  if (int Res = cmpNumbers(RMWI->isVolatile(),
849  cast<AtomicRMWInst>(R)->isVolatile()))
850  return Res;
851  if (int Res = cmpNumbers(RMWI->getOrdering(),
852  cast<AtomicRMWInst>(R)->getOrdering()))
853  return Res;
854  return cmpNumbers(RMWI->getSynchScope(),
855  cast<AtomicRMWInst>(R)->getSynchScope());
856  }
857  return 0;
858 }
859 
860 // Determine whether two GEP operations perform the same underlying arithmetic.
861 // Read method declaration comments for more details.
862 int FunctionComparator::cmpGEPs(const GEPOperator *GEPL,
863  const GEPOperator *GEPR) {
864 
865  unsigned int ASL = GEPL->getPointerAddressSpace();
866  unsigned int ASR = GEPR->getPointerAddressSpace();
867 
868  if (int Res = cmpNumbers(ASL, ASR))
869  return Res;
870 
871  // When we have target data, we can reduce the GEP down to the value in bytes
872  // added to the address.
873  const DataLayout &DL = FnL->getParent()->getDataLayout();
874  unsigned BitWidth = DL.getPointerSizeInBits(ASL);
875  APInt OffsetL(BitWidth, 0), OffsetR(BitWidth, 0);
876  if (GEPL->accumulateConstantOffset(DL, OffsetL) &&
877  GEPR->accumulateConstantOffset(DL, OffsetR))
878  return cmpAPInts(OffsetL, OffsetR);
879 
880  if (int Res = cmpNumbers((uint64_t)GEPL->getPointerOperand()->getType(),
881  (uint64_t)GEPR->getPointerOperand()->getType()))
882  return Res;
883 
884  if (int Res = cmpNumbers(GEPL->getNumOperands(), GEPR->getNumOperands()))
885  return Res;
886 
887  for (unsigned i = 0, e = GEPL->getNumOperands(); i != e; ++i) {
888  if (int Res = cmpValues(GEPL->getOperand(i), GEPR->getOperand(i)))
889  return Res;
890  }
891 
892  return 0;
893 }
894 
895 /// Compare two values used by the two functions under pair-wise comparison. If
896 /// this is the first time the values are seen, they're added to the mapping so
897 /// that we will detect mismatches on next use.
898 /// See comments in declaration for more details.
899 int FunctionComparator::cmpValues(const Value *L, const Value *R) {
900  // Catch self-reference case.
901  if (L == FnL) {
902  if (R == FnR)
903  return 0;
904  return -1;
905  }
906  if (R == FnR) {
907  if (L == FnL)
908  return 0;
909  return 1;
910  }
911 
912  const Constant *ConstL = dyn_cast<Constant>(L);
913  const Constant *ConstR = dyn_cast<Constant>(R);
914  if (ConstL && ConstR) {
915  if (L == R)
916  return 0;
917  return cmpConstants(ConstL, ConstR);
918  }
919 
920  if (ConstL)
921  return 1;
922  if (ConstR)
923  return -1;
924 
925  const InlineAsm *InlineAsmL = dyn_cast<InlineAsm>(L);
926  const InlineAsm *InlineAsmR = dyn_cast<InlineAsm>(R);
927 
928  if (InlineAsmL && InlineAsmR)
929  return cmpNumbers((uint64_t)L, (uint64_t)R);
930  if (InlineAsmL)
931  return 1;
932  if (InlineAsmR)
933  return -1;
934 
935  auto LeftSN = sn_mapL.insert(std::make_pair(L, sn_mapL.size())),
936  RightSN = sn_mapR.insert(std::make_pair(R, sn_mapR.size()));
937 
938  return cmpNumbers(LeftSN.first->second, RightSN.first->second);
939 }
940 // Test whether two basic blocks have equivalent behaviour.
941 int FunctionComparator::compare(const BasicBlock *BBL, const BasicBlock *BBR) {
942  BasicBlock::const_iterator InstL = BBL->begin(), InstLE = BBL->end();
943  BasicBlock::const_iterator InstR = BBR->begin(), InstRE = BBR->end();
944 
945  do {
946  if (int Res = cmpValues(InstL, InstR))
947  return Res;
948 
949  const GetElementPtrInst *GEPL = dyn_cast<GetElementPtrInst>(InstL);
950  const GetElementPtrInst *GEPR = dyn_cast<GetElementPtrInst>(InstR);
951 
952  if (GEPL && !GEPR)
953  return 1;
954  if (GEPR && !GEPL)
955  return -1;
956 
957  if (GEPL && GEPR) {
958  if (int Res =
959  cmpValues(GEPL->getPointerOperand(), GEPR->getPointerOperand()))
960  return Res;
961  if (int Res = cmpGEPs(GEPL, GEPR))
962  return Res;
963  } else {
964  if (int Res = cmpOperations(InstL, InstR))
965  return Res;
966  assert(InstL->getNumOperands() == InstR->getNumOperands());
967 
968  for (unsigned i = 0, e = InstL->getNumOperands(); i != e; ++i) {
969  Value *OpL = InstL->getOperand(i);
970  Value *OpR = InstR->getOperand(i);
971  if (int Res = cmpValues(OpL, OpR))
972  return Res;
973  if (int Res = cmpNumbers(OpL->getValueID(), OpR->getValueID()))
974  return Res;
975  // TODO: Already checked in cmpOperation
976  if (int Res = cmpTypes(OpL->getType(), OpR->getType()))
977  return Res;
978  }
979  }
980 
981  ++InstL, ++InstR;
982  } while (InstL != InstLE && InstR != InstRE);
983 
984  if (InstL != InstLE && InstR == InstRE)
985  return 1;
986  if (InstL == InstLE && InstR != InstRE)
987  return -1;
988  return 0;
989 }
990 
991 // Test whether the two functions have equivalent behaviour.
993 
994  sn_mapL.clear();
995  sn_mapR.clear();
996 
997  if (int Res = cmpAttrs(FnL->getAttributes(), FnR->getAttributes()))
998  return Res;
999 
1000  if (int Res = cmpNumbers(FnL->hasGC(), FnR->hasGC()))
1001  return Res;
1002 
1003  if (FnL->hasGC()) {
1004  if (int Res = cmpNumbers((uint64_t)FnL->getGC(), (uint64_t)FnR->getGC()))
1005  return Res;
1006  }
1007 
1008  if (int Res = cmpNumbers(FnL->hasSection(), FnR->hasSection()))
1009  return Res;
1010 
1011  if (FnL->hasSection()) {
1012  if (int Res = cmpStrings(FnL->getSection(), FnR->getSection()))
1013  return Res;
1014  }
1015 
1016  if (int Res = cmpNumbers(FnL->isVarArg(), FnR->isVarArg()))
1017  return Res;
1018 
1019  // TODO: if it's internal and only used in direct calls, we could handle this
1020  // case too.
1021  if (int Res = cmpNumbers(FnL->getCallingConv(), FnR->getCallingConv()))
1022  return Res;
1023 
1024  if (int Res = cmpTypes(FnL->getFunctionType(), FnR->getFunctionType()))
1025  return Res;
1026 
1027  assert(FnL->arg_size() == FnR->arg_size() &&
1028  "Identically typed functions have different numbers of args!");
1029 
1030  // Visit the arguments so that they get enumerated in the order they're
1031  // passed in.
1032  for (Function::const_arg_iterator ArgLI = FnL->arg_begin(),
1033  ArgRI = FnR->arg_begin(),
1034  ArgLE = FnL->arg_end();
1035  ArgLI != ArgLE; ++ArgLI, ++ArgRI) {
1036  if (cmpValues(ArgLI, ArgRI) != 0)
1037  llvm_unreachable("Arguments repeat!");
1038  }
1039 
1040  // We do a CFG-ordered walk since the actual ordering of the blocks in the
1041  // linked list is immaterial. Our walk starts at the entry block for both
1042  // functions, then takes each block from each terminator in order. As an
1043  // artifact, this also means that unreachable blocks are ignored.
1044  SmallVector<const BasicBlock *, 8> FnLBBs, FnRBBs;
1045  SmallSet<const BasicBlock *, 128> VisitedBBs; // in terms of F1.
1046 
1047  FnLBBs.push_back(&FnL->getEntryBlock());
1048  FnRBBs.push_back(&FnR->getEntryBlock());
1049 
1050  VisitedBBs.insert(FnLBBs[0]);
1051  while (!FnLBBs.empty()) {
1052  const BasicBlock *BBL = FnLBBs.pop_back_val();
1053  const BasicBlock *BBR = FnRBBs.pop_back_val();
1054 
1055  if (int Res = cmpValues(BBL, BBR))
1056  return Res;
1057 
1058  if (int Res = compare(BBL, BBR))
1059  return Res;
1060 
1061  const TerminatorInst *TermL = BBL->getTerminator();
1062  const TerminatorInst *TermR = BBR->getTerminator();
1063 
1064  assert(TermL->getNumSuccessors() == TermR->getNumSuccessors());
1065  for (unsigned i = 0, e = TermL->getNumSuccessors(); i != e; ++i) {
1066  if (!VisitedBBs.insert(TermL->getSuccessor(i)).second)
1067  continue;
1068 
1069  FnLBBs.push_back(TermL->getSuccessor(i));
1070  FnRBBs.push_back(TermR->getSuccessor(i));
1071  }
1072  }
1073  return 0;
1074 }
1075 
1076 namespace {
1077 
1078 /// MergeFunctions finds functions which will generate identical machine code,
1079 /// by considering all pointer types to be equivalent. Once identified,
1080 /// MergeFunctions will fold them by replacing a call to one to a call to a
1081 /// bitcast of the other.
1082 ///
1083 class MergeFunctions : public ModulePass {
1084 public:
1085  static char ID;
1086  MergeFunctions()
1087  : ModulePass(ID), HasGlobalAliases(false) {
1089  }
1090 
1091  bool runOnModule(Module &M) override;
1092 
1093 private:
1094  typedef std::set<FunctionNode> FnTreeType;
1095 
1096  /// A work queue of functions that may have been modified and should be
1097  /// analyzed again.
1098  std::vector<WeakVH> Deferred;
1099 
1100  /// Checks the rules of order relation introduced among functions set.
1101  /// Returns true, if sanity check has been passed, and false if failed.
1102  bool doSanityCheck(std::vector<WeakVH> &Worklist);
1103 
1104  /// Insert a ComparableFunction into the FnTree, or merge it away if it's
1105  /// equal to one that's already present.
1106  bool insert(Function *NewFunction);
1107 
1108  /// Remove a Function from the FnTree and queue it up for a second sweep of
1109  /// analysis.
1110  void remove(Function *F);
1111 
1112  /// Find the functions that use this Value and remove them from FnTree and
1113  /// queue the functions.
1114  void removeUsers(Value *V);
1115 
1116  /// Replace all direct calls of Old with calls of New. Will bitcast New if
1117  /// necessary to make types match.
1118  void replaceDirectCallers(Function *Old, Function *New);
1119 
1120  /// Merge two equivalent functions. Upon completion, G may be deleted, or may
1121  /// be converted into a thunk. In either case, it should never be visited
1122  /// again.
1123  void mergeTwoFunctions(Function *F, Function *G);
1124 
1125  /// Replace G with a thunk or an alias to F. Deletes G.
1126  void writeThunkOrAlias(Function *F, Function *G);
1127 
1128  /// Replace G with a simple tail call to bitcast(F). Also replace direct uses
1129  /// of G with bitcast(F). Deletes G.
1130  void writeThunk(Function *F, Function *G);
1131 
1132  /// Replace G with an alias to F. Deletes G.
1133  void writeAlias(Function *F, Function *G);
1134 
1135  /// Replace function F with function G in the function tree.
1136  void replaceFunctionInTree(FnTreeType::iterator &IterToF, Function *G);
1137 
1138  /// The set of all distinct functions. Use the insert() and remove() methods
1139  /// to modify it.
1140  FnTreeType FnTree;
1141 
1142  /// Whether or not the target supports global aliases.
1143  bool HasGlobalAliases;
1144 };
1145 
1146 } // end anonymous namespace
1147 
1148 char MergeFunctions::ID = 0;
1149 INITIALIZE_PASS(MergeFunctions, "mergefunc", "Merge Functions", false, false)
1150 
1152  return new MergeFunctions();
1153 }
1154 
1155 bool MergeFunctions::doSanityCheck(std::vector<WeakVH> &Worklist) {
1156  if (const unsigned Max = NumFunctionsForSanityCheck) {
1157  unsigned TripleNumber = 0;
1158  bool Valid = true;
1159 
1160  dbgs() << "MERGEFUNC-SANITY: Started for first " << Max << " functions.\n";
1161 
1162  unsigned i = 0;
1163  for (std::vector<WeakVH>::iterator I = Worklist.begin(), E = Worklist.end();
1164  I != E && i < Max; ++I, ++i) {
1165  unsigned j = i;
1166  for (std::vector<WeakVH>::iterator J = I; J != E && j < Max; ++J, ++j) {
1167  Function *F1 = cast<Function>(*I);
1168  Function *F2 = cast<Function>(*J);
1169  int Res1 = FunctionComparator(F1, F2).compare();
1170  int Res2 = FunctionComparator(F2, F1).compare();
1171 
1172  // If F1 <= F2, then F2 >= F1, otherwise report failure.
1173  if (Res1 != -Res2) {
1174  dbgs() << "MERGEFUNC-SANITY: Non-symmetric; triple: " << TripleNumber
1175  << "\n";
1176  F1->dump();
1177  F2->dump();
1178  Valid = false;
1179  }
1180 
1181  if (Res1 == 0)
1182  continue;
1183 
1184  unsigned k = j;
1185  for (std::vector<WeakVH>::iterator K = J; K != E && k < Max;
1186  ++k, ++K, ++TripleNumber) {
1187  if (K == J)
1188  continue;
1189 
1190  Function *F3 = cast<Function>(*K);
1191  int Res3 = FunctionComparator(F1, F3).compare();
1192  int Res4 = FunctionComparator(F2, F3).compare();
1193 
1194  bool Transitive = true;
1195 
1196  if (Res1 != 0 && Res1 == Res4) {
1197  // F1 > F2, F2 > F3 => F1 > F3
1198  Transitive = Res3 == Res1;
1199  } else if (Res3 != 0 && Res3 == -Res4) {
1200  // F1 > F3, F3 > F2 => F1 > F2
1201  Transitive = Res3 == Res1;
1202  } else if (Res4 != 0 && -Res3 == Res4) {
1203  // F2 > F3, F3 > F1 => F2 > F1
1204  Transitive = Res4 == -Res1;
1205  }
1206 
1207  if (!Transitive) {
1208  dbgs() << "MERGEFUNC-SANITY: Non-transitive; triple: "
1209  << TripleNumber << "\n";
1210  dbgs() << "Res1, Res3, Res4: " << Res1 << ", " << Res3 << ", "
1211  << Res4 << "\n";
1212  F1->dump();
1213  F2->dump();
1214  F3->dump();
1215  Valid = false;
1216  }
1217  }
1218  }
1219  }
1220 
1221  dbgs() << "MERGEFUNC-SANITY: " << (Valid ? "Passed." : "Failed.") << "\n";
1222  return Valid;
1223  }
1224  return true;
1225 }
1226 
1227 bool MergeFunctions::runOnModule(Module &M) {
1228  bool Changed = false;
1229 
1230  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
1231  if (!I->isDeclaration() && !I->hasAvailableExternallyLinkage())
1232  Deferred.push_back(WeakVH(I));
1233  }
1234 
1235  do {
1236  std::vector<WeakVH> Worklist;
1237  Deferred.swap(Worklist);
1238 
1239  DEBUG(doSanityCheck(Worklist));
1240 
1241  DEBUG(dbgs() << "size of module: " << M.size() << '\n');
1242  DEBUG(dbgs() << "size of worklist: " << Worklist.size() << '\n');
1243 
1244  // Insert only strong functions and merge them. Strong function merging
1245  // always deletes one of them.
1246  for (std::vector<WeakVH>::iterator I = Worklist.begin(),
1247  E = Worklist.end(); I != E; ++I) {
1248  if (!*I) continue;
1249  Function *F = cast<Function>(*I);
1250  if (!F->isDeclaration() && !F->hasAvailableExternallyLinkage() &&
1251  !F->mayBeOverridden()) {
1252  Changed |= insert(F);
1253  }
1254  }
1255 
1256  // Insert only weak functions and merge them. By doing these second we
1257  // create thunks to the strong function when possible. When two weak
1258  // functions are identical, we create a new strong function with two weak
1259  // weak thunks to it which are identical but not mergable.
1260  for (std::vector<WeakVH>::iterator I = Worklist.begin(),
1261  E = Worklist.end(); I != E; ++I) {
1262  if (!*I) continue;
1263  Function *F = cast<Function>(*I);
1264  if (!F->isDeclaration() && !F->hasAvailableExternallyLinkage() &&
1265  F->mayBeOverridden()) {
1266  Changed |= insert(F);
1267  }
1268  }
1269  DEBUG(dbgs() << "size of FnTree: " << FnTree.size() << '\n');
1270  } while (!Deferred.empty());
1271 
1272  FnTree.clear();
1273 
1274  return Changed;
1275 }
1276 
1277 // Replace direct callers of Old with New.
1278 void MergeFunctions::replaceDirectCallers(Function *Old, Function *New) {
1279  Constant *BitcastNew = ConstantExpr::getBitCast(New, Old->getType());
1280  for (auto UI = Old->use_begin(), UE = Old->use_end(); UI != UE;) {
1281  Use *U = &*UI;
1282  ++UI;
1283  CallSite CS(U->getUser());
1284  if (CS && CS.isCallee(U)) {
1285  remove(CS.getInstruction()->getParent()->getParent());
1286  U->set(BitcastNew);
1287  }
1288  }
1289 }
1290 
1291 // Replace G with an alias to F if possible, or else a thunk to F. Deletes G.
1292 void MergeFunctions::writeThunkOrAlias(Function *F, Function *G) {
1293  if (HasGlobalAliases && G->hasUnnamedAddr()) {
1294  if (G->hasExternalLinkage() || G->hasLocalLinkage() ||
1295  G->hasWeakLinkage()) {
1296  writeAlias(F, G);
1297  return;
1298  }
1299  }
1300 
1301  writeThunk(F, G);
1302 }
1303 
1304 // Helper for writeThunk,
1305 // Selects proper bitcast operation,
1306 // but a bit simpler then CastInst::getCastOpcode.
1307 static Value *createCast(IRBuilder<false> &Builder, Value *V, Type *DestTy) {
1308  Type *SrcTy = V->getType();
1309  if (SrcTy->isStructTy()) {
1310  assert(DestTy->isStructTy());
1311  assert(SrcTy->getStructNumElements() == DestTy->getStructNumElements());
1312  Value *Result = UndefValue::get(DestTy);
1313  for (unsigned int I = 0, E = SrcTy->getStructNumElements(); I < E; ++I) {
1314  Value *Element = createCast(
1315  Builder, Builder.CreateExtractValue(V, makeArrayRef(I)),
1316  DestTy->getStructElementType(I));
1317 
1318  Result =
1319  Builder.CreateInsertValue(Result, Element, makeArrayRef(I));
1320  }
1321  return Result;
1322  }
1323  assert(!DestTy->isStructTy());
1324  if (SrcTy->isIntegerTy() && DestTy->isPointerTy())
1325  return Builder.CreateIntToPtr(V, DestTy);
1326  else if (SrcTy->isPointerTy() && DestTy->isIntegerTy())
1327  return Builder.CreatePtrToInt(V, DestTy);
1328  else
1329  return Builder.CreateBitCast(V, DestTy);
1330 }
1331 
1332 // Replace G with a simple tail call to bitcast(F). Also replace direct uses
1333 // of G with bitcast(F). Deletes G.
1334 void MergeFunctions::writeThunk(Function *F, Function *G) {
1335  if (!G->mayBeOverridden()) {
1336  // Redirect direct callers of G to F.
1337  replaceDirectCallers(G, F);
1338  }
1339 
1340  // If G was internal then we may have replaced all uses of G with F. If so,
1341  // stop here and delete G. There's no need for a thunk.
1342  if (G->hasLocalLinkage() && G->use_empty()) {
1343  G->eraseFromParent();
1344  return;
1345  }
1346 
1347  Function *NewG = Function::Create(G->getFunctionType(), G->getLinkage(), "",
1348  G->getParent());
1349  BasicBlock *BB = BasicBlock::Create(F->getContext(), "", NewG);
1350  IRBuilder<false> Builder(BB);
1351 
1353  unsigned i = 0;
1354  FunctionType *FFTy = F->getFunctionType();
1355  for (Function::arg_iterator AI = NewG->arg_begin(), AE = NewG->arg_end();
1356  AI != AE; ++AI) {
1357  Args.push_back(createCast(Builder, (Value*)AI, FFTy->getParamType(i)));
1358  ++i;
1359  }
1360 
1361  CallInst *CI = Builder.CreateCall(F, Args);
1362  CI->setTailCall();
1363  CI->setCallingConv(F->getCallingConv());
1364  if (NewG->getReturnType()->isVoidTy()) {
1365  Builder.CreateRetVoid();
1366  } else {
1367  Builder.CreateRet(createCast(Builder, CI, NewG->getReturnType()));
1368  }
1369 
1370  NewG->copyAttributesFrom(G);
1371  NewG->takeName(G);
1372  removeUsers(G);
1373  G->replaceAllUsesWith(NewG);
1374  G->eraseFromParent();
1375 
1376  DEBUG(dbgs() << "writeThunk: " << NewG->getName() << '\n');
1377  ++NumThunksWritten;
1378 }
1379 
1380 // Replace G with an alias to F and delete G.
1381 void MergeFunctions::writeAlias(Function *F, Function *G) {
1382  PointerType *PTy = G->getType();
1383  auto *GA = GlobalAlias::create(PTy, G->getLinkage(), "", F);
1384  F->setAlignment(std::max(F->getAlignment(), G->getAlignment()));
1385  GA->takeName(G);
1386  GA->setVisibility(G->getVisibility());
1387  removeUsers(G);
1388  G->replaceAllUsesWith(GA);
1389  G->eraseFromParent();
1390 
1391  DEBUG(dbgs() << "writeAlias: " << GA->getName() << '\n');
1392  ++NumAliasesWritten;
1393 }
1394 
1395 // Merge two equivalent functions. Upon completion, Function G is deleted.
1396 void MergeFunctions::mergeTwoFunctions(Function *F, Function *G) {
1397  if (F->mayBeOverridden()) {
1398  assert(G->mayBeOverridden());
1399 
1400  // Make them both thunks to the same internal function.
1402  F->getParent());
1403  H->copyAttributesFrom(F);
1404  H->takeName(F);
1405  removeUsers(F);
1406  F->replaceAllUsesWith(H);
1407 
1408  unsigned MaxAlignment = std::max(G->getAlignment(), H->getAlignment());
1409 
1410  if (HasGlobalAliases) {
1411  writeAlias(F, G);
1412  writeAlias(F, H);
1413  } else {
1414  writeThunk(F, G);
1415  writeThunk(F, H);
1416  }
1417 
1418  F->setAlignment(MaxAlignment);
1420  ++NumDoubleWeak;
1421  } else {
1422  writeThunkOrAlias(F, G);
1423  }
1424 
1425  ++NumFunctionsMerged;
1426 }
1427 
1428 /// Replace function F for function G in the map.
1429 void MergeFunctions::replaceFunctionInTree(FnTreeType::iterator &IterToF,
1430  Function *G) {
1431  Function *F = IterToF->getFunc();
1432 
1433  // A total order is already guaranteed otherwise because we process strong
1434  // functions before weak functions.
1435  assert(((F->mayBeOverridden() && G->mayBeOverridden()) ||
1436  (!F->mayBeOverridden() && !G->mayBeOverridden())) &&
1437  "Only change functions if both are strong or both are weak");
1438  (void)F;
1439 
1440  IterToF->replaceBy(G);
1441 }
1442 
1443 // Insert a ComparableFunction into the FnTree, or merge it away if equal to one
1444 // that was already inserted.
1445 bool MergeFunctions::insert(Function *NewFunction) {
1446  std::pair<FnTreeType::iterator, bool> Result =
1447  FnTree.insert(FunctionNode(NewFunction));
1448 
1449  if (Result.second) {
1450  DEBUG(dbgs() << "Inserting as unique: " << NewFunction->getName() << '\n');
1451  return false;
1452  }
1453 
1454  const FunctionNode &OldF = *Result.first;
1455 
1456  // Don't merge tiny functions, since it can just end up making the function
1457  // larger.
1458  // FIXME: Should still merge them if they are unnamed_addr and produce an
1459  // alias.
1460  if (NewFunction->size() == 1) {
1461  if (NewFunction->front().size() <= 2) {
1462  DEBUG(dbgs() << NewFunction->getName()
1463  << " is to small to bother merging\n");
1464  return false;
1465  }
1466  }
1467 
1468  // Impose a total order (by name) on the replacement of functions. This is
1469  // important when operating on more than one module independently to prevent
1470  // cycles of thunks calling each other when the modules are linked together.
1471  //
1472  // When one function is weak and the other is strong there is an order imposed
1473  // already. We process strong functions before weak functions.
1474  if ((OldF.getFunc()->mayBeOverridden() && NewFunction->mayBeOverridden()) ||
1475  (!OldF.getFunc()->mayBeOverridden() && !NewFunction->mayBeOverridden()))
1476  if (OldF.getFunc()->getName() > NewFunction->getName()) {
1477  // Swap the two functions.
1478  Function *F = OldF.getFunc();
1479  replaceFunctionInTree(Result.first, NewFunction);
1480  NewFunction = F;
1481  assert(OldF.getFunc() != F && "Must have swapped the functions.");
1482  }
1483 
1484  // Never thunk a strong function to a weak function.
1485  assert(!OldF.getFunc()->mayBeOverridden() || NewFunction->mayBeOverridden());
1486 
1487  DEBUG(dbgs() << " " << OldF.getFunc()->getName()
1488  << " == " << NewFunction->getName() << '\n');
1489 
1490  Function *DeleteF = NewFunction;
1491  mergeTwoFunctions(OldF.getFunc(), DeleteF);
1492  return true;
1493 }
1494 
1495 // Remove a function from FnTree. If it was already in FnTree, add
1496 // it to Deferred so that we'll look at it in the next round.
1498  // We need to make sure we remove F, not a function "equal" to F per the
1499  // function equality comparator.
1500  FnTreeType::iterator found = FnTree.find(FunctionNode(F));
1501  size_t Erased = 0;
1502  if (found != FnTree.end() && found->getFunc() == F) {
1503  Erased = 1;
1504  FnTree.erase(found);
1505  }
1506 
1507  if (Erased) {
1508  DEBUG(dbgs() << "Removed " << F->getName()
1509  << " from set and deferred it.\n");
1510  Deferred.emplace_back(F);
1511  }
1512 }
1513 
1514 // For each instruction used by the value, remove() the function that contains
1515 // the instruction. This should happen right before a call to RAUW.
1516 void MergeFunctions::removeUsers(Value *V) {
1517  std::vector<Value *> Worklist;
1518  Worklist.push_back(V);
1519  while (!Worklist.empty()) {
1520  Value *V = Worklist.back();
1521  Worklist.pop_back();
1522 
1523  for (User *U : V->users()) {
1524  if (Instruction *I = dyn_cast<Instruction>(U)) {
1525  remove(I->getParent()->getParent());
1526  } else if (isa<GlobalValue>(U)) {
1527  // do nothing
1528  } else if (Constant *C = dyn_cast<Constant>(U)) {
1529  for (User *UU : C->users())
1530  Worklist.push_back(UU);
1531  }
1532  }
1533  }
1534 }
use_iterator use_end()
Definition: Value.h:281
7: Labels
Definition: Type.h:63
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:104
LinkageTypes getLinkage() const
Definition: GlobalValue.h:289
static Value * createCast(IRBuilder< false > &Builder, Value *V, Type *DestTy)
This class is the base class for the comparison instructions.
Definition: InstrTypes.h:679
ExtractValueInst - This instruction extracts a struct member or array element value from an aggregate...
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
LLVMContext & getContext() const
getContext - Return a reference to the LLVMContext associated with this function. ...
Definition: Function.cpp:223
VisibilityTypes getVisibility() const
Definition: GlobalValue.h:139
unsigned getStructNumElements() const
Definition: Type.cpp:196
STATISTIC(NumFunctions,"Total number of functions")
size_t size() const
size - Get the string size.
Definition: StringRef.h:113
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:114
unsigned getNumParams() const
getNumParams - Return the number of fixed parameters this function type requires. ...
Definition: DerivedTypes.h:136
2: 32-bit floating point type
Definition: Type.h:58
FenceInst - an instruction for ordering other memory operations.
Definition: Instructions.h:445
AtomicCmpXchgInst - an instruction that atomically checks whether a specified value is in a memory lo...
Definition: Instructions.h:515
std::error_code remove(const Twine &path, bool IgnoreNonExisting=true)
Remove path.
ModulePass * createMergeFunctionsPass()
createMergeFunctionsPass - This pass discovers identical functions and collapses them.
unsigned getNumOperands() const
Definition: User.h:138
CallInst - This class represents a function call, abstracting a target machine's calling convention...
Like Internal, but omit from symbol table.
Definition: GlobalValue.h:48
bool hasAvailableExternallyLinkage() const
Definition: GlobalValue.h:261
iterator begin(unsigned Slot) const
Type * getReturnType() const
Definition: Function.cpp:233
arg_iterator arg_end()
Definition: Function.h:480
12: Structures
Definition: Type.h:71
unsigned getAlignment() const
Returns the alignment field of an attribute as a byte alignment value.
Definition: Attributes.cpp:157
F(f)
4: 80-bit floating point type (X87)
Definition: Type.h:60
unsigned getAddressSpace() const
Return the address space of the Pointer type.
Definition: DerivedTypes.h:472
LoadInst - an instruction for reading from memory.
Definition: Instructions.h:177
AtomicRMWInst - an instruction that atomically reads a memory location, combines it with another valu...
Definition: Instructions.h:674
14: Pointers
Definition: Type.h:73
void setAlignment(unsigned Align)
Definition: Globals.cpp:77
11: Functions
Definition: Type.h:70
CallingConv::ID getCallingConv() const
getCallingConv()/setCallingConv(CC) - These method get and set the calling convention of this functio...
Definition: Function.h:172
StringRef getName() const
Return a constant reference to the value's name.
Definition: Value.cpp:188
iterator begin()
Instruction iterator methods.
Definition: BasicBlock.h:231
void setCallingConv(CallingConv::ID CC)
int compare(StringRef RHS) const
compare - Compare two strings; the result is -1, 0, or 1 if this string is lexicographically less tha...
Definition: StringRef.h:148
Value * CreateExtractValue(Value *Agg, ArrayRef< unsigned > Idxs, const Twine &Name="")
Definition: IRBuilder.h:1541
bool isPacked() const
Definition: DerivedTypes.h:242
ArrayRef< T > makeArrayRef(const T &OneElt)
Construct an ArrayRef from a single element.
Definition: ArrayRef.h:308
T LLVM_ATTRIBUTE_UNUSED_RESULT pop_back_val()
Definition: SmallVector.h:406
StructType - Class to represent struct types.
Definition: DerivedTypes.h:191
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Definition: ErrorHandling.h:98
Value * CreateIntToPtr(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1249
A Use represents the edge between a Value definition and its users.
Definition: Use.h:69
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:517
#define false
Definition: ConvertUTF.c:65
#define G(x, y, z)
Definition: MD5.cpp:52
FunctionType - Class to represent function types.
Definition: DerivedTypes.h:96
ConstantExpr - a constant value that is initialized with an expression using other constant values...
Definition: Constants.h:852
bool accumulateConstantOffset(const DataLayout &DL, APInt &Offset) const
Accumulate the constant address offset of this GEP if possible.
Definition: Operator.cpp:15
bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const
Definition: SmallVector.h:57
Value handle that is nullable, but tries to track the Value.
Definition: ValueHandle.h:141
unsigned getAlignment() const
Definition: GlobalObject.h:46
ArrayType - Class to represent array types.
Definition: DerivedTypes.h:336
bool isFirstClassType() const
isFirstClassType - Return true if the type is "first class", meaning it is a valid type for a Value...
Definition: Type.h:242
TypeID getTypeID() const
getTypeID - Return the type id for the type.
Definition: Type.h:134
StoreInst - an instruction for storing to memory.
Definition: Instructions.h:316
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:351
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:256
void initializeMergeFunctionsPass(PassRegistry &)
Type * getElementType() const
Definition: DerivedTypes.h:323
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:134
PointerType - Class to represent pointers.
Definition: DerivedTypes.h:449
10: Arbitrary bit width integers
Definition: Type.h:69
static Constant * getBitCast(Constant *C, Type *Ty, bool OnlyIfReduced=false)
Definition: Constants.cpp:1835
unsigned getNumSuccessors() const
Return the number of successors that this terminator has.
Definition: InstrTypes.h:57
GetElementPtrInst - an instruction for type-safe pointer arithmetic to access elements of arrays and ...
Definition: Instructions.h:830
A self-contained host- and target-independent arbitrary-precision floating-point software implementat...
Definition: APFloat.h:122
0: type with no size
Definition: Type.h:56
unsigned getNumSlots() const
Return the number of slots used in this attribute list.
Type * getParamType(unsigned i) const
Parameter type accessors.
Definition: DerivedTypes.h:131
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:325
Subclasses of this class are all able to terminate a basic block.
Definition: InstrTypes.h:35
LLVM Basic Block Representation.
Definition: BasicBlock.h:65
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:45
BasicBlock * getSuccessor(unsigned idx) const
Return the specified successor.
Definition: InstrTypes.h:62
static bool mayBeOverridden(LinkageTypes Linkage)
Whether the definition of this global may be replaced by something non-equivalent at link time...
Definition: GlobalValue.h:245
static GlobalAlias * create(PointerType *Ty, LinkageTypes Linkage, const Twine &Name, Constant *Aliasee, Module *Parent)
If a parent module is specified, the alias is automatically inserted into the end of the specified mo...
Definition: Globals.cpp:243
Type * getElementType(unsigned N) const
Definition: DerivedTypes.h:291
Value * CreatePtrToInt(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1245
This is an important base class in LLVM.
Definition: Constant.h:41
SmallSet - This maintains a set of unique values, optimizing for the case when the set is small (less...
Definition: SmallSet.h:32
This file contains the declarations for the subclasses of Constant, which represent the different fla...
#define H(x, y, z)
Definition: MD5.cpp:53
uint64_t getNumElements() const
Definition: DerivedTypes.h:352
unsigned getBitWidth() const
Return the number of bits in the APInt.
Definition: APInt.h:1273
unsigned getValueID() const
Return an ID for the concrete type of this object.
Definition: Value.h:362
Value * getPointerOperand()
Definition: Operator.h:388
size_t size() const
Definition: Function.h:462
void copyAttributesFrom(const GlobalValue *Src) override
copyAttributesFrom - copy all additional attributes (those not needed to create a Function) from the ...
Definition: Function.cpp:416
6: 128-bit floating point type (two 64-bits, PowerPC)
Definition: Type.h:62
Value * getOperand(unsigned i) const
Definition: User.h:118
static BasicBlock * Create(LLVMContext &Context, const Twine &Name="", Function *Parent=nullptr, BasicBlock *InsertBefore=nullptr)
Creates a new BasicBlock.
Definition: BasicBlock.h:103
arg_iterator arg_begin()
Definition: Function.h:472
std::pair< NoneType, bool > insert(const T &V)
insert - Insert an element into the set if it isn't already there.
Definition: SmallSet.h:69
ConstantVector - Constant Vector Declarations.
Definition: Constants.h:461
void setTailCall(bool isTC=true)
bool isPointerTy() const
isPointerTy - True if this is an instance of PointerType.
Definition: Type.h:217
static UndefValue * get(Type *T)
get() - Static factory methods - Return an 'undef' object of the specified type.
Definition: Constants.cpp:1473
bool hasWeakLinkage() const
Definition: GlobalValue.h:268
void dump() const
Support for debugging, callable in GDB: V->dump()
Definition: AsmWriter.cpp:3353
#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)
Definition: PassSupport.h:56
bool ugt(const APInt &RHS) const
Unsigned greather than comparison.
Definition: APInt.h:1101
13: Arrays
Definition: Type.h:72
bool hasExternalLinkage() const
Definition: GlobalValue.h:260
15: SIMD 'packed' format, or other vector type
Definition: Type.h:74
iterator end()
Definition: BasicBlock.h:233
Value * CreateBitCast(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1253
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:861
Module.h This file contains the declarations for the Module class.
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:222
iterator end(unsigned Slot) const
bool isNullValue() const
isNullValue - Return true if this is the value that would be returned by getNullValue.
Definition: Constants.cpp:75
Value handle that asserts if the Value is deleted.
Definition: ValueHandle.h:187
void setLinkage(LinkageTypes LT)
Definition: GlobalValue.h:284
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:123
8: Metadata
Definition: Type.h:64
VectorType - Class to represent vector types.
Definition: DerivedTypes.h:362
ConstantArray - Constant Array Declarations.
Definition: Constants.h:356
Class for arbitrary precision integers.
Definition: APInt.h:73
static bool isWeak(const MCSymbolELF &Sym)
bool isIntegerTy() const
isIntegerTy - True if this is an instance of IntegerType.
Definition: Type.h:193
iterator_range< user_iterator > users()
Definition: Value.h:300
size_t size() const
Definition: Module.h:577
APInt bitcastToAPInt() const
Definition: APFloat.cpp:3084
LLVM_ATTRIBUTE_UNUSED_RESULT std::enable_if< !is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:285
void eraseFromParent() override
eraseFromParent - This method unlinks 'this' from the containing module and deletes it...
Definition: Function.cpp:241
Value * CreateInsertValue(Value *Agg, Value *Val, ArrayRef< unsigned > Idxs, const Twine &Name="")
Definition: IRBuilder.h:1549
bool isStructTy() const
isStructTy - True if this is an instance of StructType.
Definition: Type.h:209
use_iterator use_begin()
Definition: Value.h:279
PointerType * getType() const
Global values are always pointers.
Definition: GlobalValue.h:185
iterator end()
Definition: Module.h:571
bool isDeclaration() const
Return true if the primary definition of this global value is outside of the current translation unit...
Definition: Globals.cpp:128
unsigned getRawSubclassOptionalData() const
Return the raw optional flags value contained in this value.
Definition: Value.h:369
static cl::opt< unsigned > NumFunctionsForSanityCheck("mergefunc-sanity", cl::desc("How many functions in module could be used for ""MergeFunctions pass sanity check. ""'0' disables this check. Works only with '-debug' key."), cl::init(0), cl::Hidden)
#define I(x, y, z)
Definition: MD5.cpp:54
TerminatorInst * getTerminator()
Returns the terminator instruction if the block is well formed or null if the block is not well forme...
Definition: BasicBlock.cpp:124
FunctionType * getFunctionType() const
Definition: Function.cpp:227
ModulePass class - This class is used to implement unstructured interprocedural optimizations and ana...
Definition: Pass.h:236
unsigned getPointerSizeInBits(unsigned AS=0) const
Layout pointer size, in bits FIXME: The defaults need to be removed once all of the backends/clients ...
Definition: DataLayout.h:329
iterator begin()
Definition: Module.h:569
unsigned getPointerAddressSpace() const
Method to return the address space of the pointer operand.
Definition: Operator.h:406
size_t size() const
Definition: BasicBlock.h:241
AttributeSet getAttributes(LLVMContext &C, ID id)
Return the attributes for an intrinsic.
bool hasLocalLinkage() const
Definition: GlobalValue.h:280
bool isVarArg() const
Definition: DerivedTypes.h:120
int compare(DigitsT LDigits, int16_t LScale, DigitsT RDigits, int16_t RScale)
Compare two scaled numbers.
Definition: ScaledNumber.h:252
3: 64-bit floating point type
Definition: Type.h:59
bool use_empty() const
Definition: Value.h:275
Type * getReturnType() const
Definition: DerivedTypes.h:121
const BasicBlock & front() const
Definition: Function.h:464
bool operator<(int64_t V1, const APSInt &V2)
Definition: APSInt.h:332
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:365
LLVM Value Representation.
Definition: Value.h:69
bool hasUnnamedAddr() const
Definition: GlobalValue.h:130
unsigned getOpcode() const
getOpcode() returns a member of one of the enums like Instruction::Add.
Definition: Instruction.h:112
InvokeInst - Invoke instruction.
#define DEBUG(X)
Definition: Debug.h:92
Type * getStructElementType(unsigned N) const
Definition: Type.cpp:200
C - The default llvm calling convention, compatible with C.
Definition: CallingConv.h:34
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:40
static Function * Create(FunctionType *Ty, LinkageTypes Linkage, const Twine &N="", Module *M=nullptr)
Definition: Function.h:121
static bool isVolatile(Instruction *Inst)
unsigned getNumElements() const
Random access to the elements.
Definition: DerivedTypes.h:290
const fltSemantics & getSemantics() const
Definition: APFloat.h:435
bool isVoidTy() const
isVoidTy - Return true if this is 'void'.
Definition: Type.h:137
AllocaInst - an instruction to allocate memory on the stack.
Definition: Instructions.h:76
InsertValueInst - This instruction inserts a struct field of array element value into an aggregate va...
5: 128-bit floating point type (112-bit mantissa)
Definition: Type.h:61