1//===- ThreadSafetyCommon.cpp ----------------------------------*- C++ --*-===//
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// Implementation of the interfaces declared in ThreadSafetyCommon.h
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Analysis/Analyses/ThreadSafetyCommon.h"
15#include "clang/AST/Attr.h"
16#include "clang/AST/DeclCXX.h"
17#include "clang/AST/DeclObjC.h"
18#include "clang/AST/ExprCXX.h"
19#include "clang/AST/StmtCXX.h"
20#include "clang/Analysis/Analyses/PostOrderCFGView.h"
21#include "clang/Analysis/Analyses/ThreadSafetyTIL.h"
22#include "clang/Analysis/Analyses/ThreadSafetyTraverse.h"
23#include "clang/Analysis/AnalysisContext.h"
24#include "clang/Analysis/CFG.h"
25#include "clang/Basic/OperatorKinds.h"
26#include "clang/Basic/SourceLocation.h"
27#include "clang/Basic/SourceManager.h"
28#include "llvm/ADT/DenseMap.h"
29#include "llvm/ADT/SmallVector.h"
30#include "llvm/ADT/StringRef.h"
31
32#include <algorithm>
33#include <climits>
34#include <vector>
35
36
37namespace clang {
38namespace threadSafety {
39
40// From ThreadSafetyUtil.h
41std::string getSourceLiteralString(const clang::Expr *CE) {
42  switch (CE->getStmtClass()) {
43    case Stmt::IntegerLiteralClass:
44      return cast<IntegerLiteral>(CE)->getValue().toString(10, true);
45    case Stmt::StringLiteralClass: {
46      std::string ret("\"");
47      ret += cast<StringLiteral>(CE)->getString();
48      ret += "\"";
49      return ret;
50    }
51    case Stmt::CharacterLiteralClass:
52    case Stmt::CXXNullPtrLiteralExprClass:
53    case Stmt::GNUNullExprClass:
54    case Stmt::CXXBoolLiteralExprClass:
55    case Stmt::FloatingLiteralClass:
56    case Stmt::ImaginaryLiteralClass:
57    case Stmt::ObjCStringLiteralClass:
58    default:
59      return "#lit";
60  }
61}
62
63namespace til {
64
65// Return true if E is a variable that points to an incomplete Phi node.
66static bool isIncompleteVar(const SExpr *E) {
67  if (const auto *V = dyn_cast<Variable>(E)) {
68    if (const auto *Ph = dyn_cast<Phi>(V->definition()))
69      return Ph->status() == Phi::PH_Incomplete;
70  }
71  return false;
72}
73
74}  // end namespace til
75
76
77typedef SExprBuilder::CallingContext CallingContext;
78
79
80til::SExpr *SExprBuilder::lookupStmt(const Stmt *S) {
81  auto It = SMap.find(S);
82  if (It != SMap.end())
83    return It->second;
84  return nullptr;
85}
86
87
88til::SCFG *SExprBuilder::buildCFG(CFGWalker &Walker) {
89  Walker.walk(*this);
90  return Scfg;
91}
92
93
94// Translate a clang statement or expression to a TIL expression.
95// Also performs substitution of variables; Ctx provides the context.
96// Dispatches on the type of S.
97til::SExpr *SExprBuilder::translate(const Stmt *S, CallingContext *Ctx) {
98  if (!S)
99    return nullptr;
100
101  // Check if S has already been translated and cached.
102  // This handles the lookup of SSA names for DeclRefExprs here.
103  if (til::SExpr *E = lookupStmt(S))
104    return E;
105
106  switch (S->getStmtClass()) {
107  case Stmt::DeclRefExprClass:
108    return translateDeclRefExpr(cast<DeclRefExpr>(S), Ctx);
109  case Stmt::CXXThisExprClass:
110    return translateCXXThisExpr(cast<CXXThisExpr>(S), Ctx);
111  case Stmt::MemberExprClass:
112    return translateMemberExpr(cast<MemberExpr>(S), Ctx);
113  case Stmt::CallExprClass:
114    return translateCallExpr(cast<CallExpr>(S), Ctx);
115  case Stmt::CXXMemberCallExprClass:
116    return translateCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), Ctx);
117  case Stmt::CXXOperatorCallExprClass:
118    return translateCXXOperatorCallExpr(cast<CXXOperatorCallExpr>(S), Ctx);
119  case Stmt::UnaryOperatorClass:
120    return translateUnaryOperator(cast<UnaryOperator>(S), Ctx);
121  case Stmt::BinaryOperatorClass:
122  case Stmt::CompoundAssignOperatorClass:
123    return translateBinaryOperator(cast<BinaryOperator>(S), Ctx);
124
125  case Stmt::ArraySubscriptExprClass:
126    return translateArraySubscriptExpr(cast<ArraySubscriptExpr>(S), Ctx);
127  case Stmt::ConditionalOperatorClass:
128    return translateConditionalOperator(cast<ConditionalOperator>(S), Ctx);
129  case Stmt::BinaryConditionalOperatorClass:
130    return translateBinaryConditionalOperator(
131             cast<BinaryConditionalOperator>(S), Ctx);
132
133  // We treat these as no-ops
134  case Stmt::ParenExprClass:
135    return translate(cast<ParenExpr>(S)->getSubExpr(), Ctx);
136  case Stmt::ExprWithCleanupsClass:
137    return translate(cast<ExprWithCleanups>(S)->getSubExpr(), Ctx);
138  case Stmt::CXXBindTemporaryExprClass:
139    return translate(cast<CXXBindTemporaryExpr>(S)->getSubExpr(), Ctx);
140
141  // Collect all literals
142  case Stmt::CharacterLiteralClass:
143  case Stmt::CXXNullPtrLiteralExprClass:
144  case Stmt::GNUNullExprClass:
145  case Stmt::CXXBoolLiteralExprClass:
146  case Stmt::FloatingLiteralClass:
147  case Stmt::ImaginaryLiteralClass:
148  case Stmt::IntegerLiteralClass:
149  case Stmt::StringLiteralClass:
150  case Stmt::ObjCStringLiteralClass:
151    return new (Arena) til::Literal(cast<Expr>(S));
152
153  case Stmt::DeclStmtClass:
154    return translateDeclStmt(cast<DeclStmt>(S), Ctx);
155  default:
156    break;
157  }
158  if (const CastExpr *CE = dyn_cast<CastExpr>(S))
159    return translateCastExpr(CE, Ctx);
160
161  return new (Arena) til::Undefined(S);
162}
163
164
165til::SExpr *SExprBuilder::translateDeclRefExpr(const DeclRefExpr *DRE,
166                                               CallingContext *Ctx) {
167  const ValueDecl *VD = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
168
169  // Function parameters require substitution and/or renaming.
170  if (const ParmVarDecl *PV = dyn_cast_or_null<ParmVarDecl>(VD)) {
171    const FunctionDecl *FD =
172        cast<FunctionDecl>(PV->getDeclContext())->getCanonicalDecl();
173    unsigned I = PV->getFunctionScopeIndex();
174
175    if (Ctx && Ctx->FunArgs && FD == Ctx->AttrDecl->getCanonicalDecl()) {
176      // Substitute call arguments for references to function parameters
177      assert(I < Ctx->NumArgs);
178      return translate(Ctx->FunArgs[I], Ctx->Prev);
179    }
180    // Map the param back to the param of the original function declaration
181    // for consistent comparisons.
182    VD = FD->getParamDecl(I);
183  }
184
185  // For non-local variables, treat it as a referenced to a named object.
186  return new (Arena) til::LiteralPtr(VD);
187}
188
189
190til::SExpr *SExprBuilder::translateCXXThisExpr(const CXXThisExpr *TE,
191                                               CallingContext *Ctx) {
192  // Substitute for 'this'
193  if (Ctx && Ctx->SelfArg)
194    return translate(Ctx->SelfArg, Ctx->Prev);
195  assert(SelfVar && "We have no variable for 'this'!");
196  return SelfVar;
197}
198
199
200til::SExpr *SExprBuilder::translateMemberExpr(const MemberExpr *ME,
201                                              CallingContext *Ctx) {
202  til::SExpr *E = translate(ME->getBase(), Ctx);
203  E = new (Arena) til::SApply(E);
204  return new (Arena) til::Project(E, ME->getMemberDecl());
205}
206
207
208til::SExpr *SExprBuilder::translateCallExpr(const CallExpr *CE,
209                                            CallingContext *Ctx) {
210  // TODO -- Lock returned
211  til::SExpr *E = translate(CE->getCallee(), Ctx);
212  for (const auto *Arg : CE->arguments()) {
213    til::SExpr *A = translate(Arg, Ctx);
214    E = new (Arena) til::Apply(E, A);
215  }
216  return new (Arena) til::Call(E, CE);
217}
218
219
220til::SExpr *SExprBuilder::translateCXXMemberCallExpr(
221    const CXXMemberCallExpr *ME, CallingContext *Ctx) {
222  return translateCallExpr(cast<CallExpr>(ME), Ctx);
223}
224
225
226til::SExpr *SExprBuilder::translateCXXOperatorCallExpr(
227    const CXXOperatorCallExpr *OCE, CallingContext *Ctx) {
228  return translateCallExpr(cast<CallExpr>(OCE), Ctx);
229}
230
231
232til::SExpr *SExprBuilder::translateUnaryOperator(const UnaryOperator *UO,
233                                                 CallingContext *Ctx) {
234  switch (UO->getOpcode()) {
235  case UO_PostInc:
236  case UO_PostDec:
237  case UO_PreInc:
238  case UO_PreDec:
239    return new (Arena) til::Undefined(UO);
240
241  // We treat these as no-ops
242  case UO_AddrOf:
243  case UO_Deref:
244  case UO_Plus:
245    return translate(UO->getSubExpr(), Ctx);
246
247  case UO_Minus:
248    return new (Arena)
249      til::UnaryOp(til::UOP_Minus, translate(UO->getSubExpr(), Ctx));
250  case UO_Not:
251    return new (Arena)
252      til::UnaryOp(til::UOP_BitNot, translate(UO->getSubExpr(), Ctx));
253  case UO_LNot:
254    return new (Arena)
255      til::UnaryOp(til::UOP_LogicNot, translate(UO->getSubExpr(), Ctx));
256
257  // Currently unsupported
258  case UO_Real:
259  case UO_Imag:
260  case UO_Extension:
261    return new (Arena) til::Undefined(UO);
262  }
263  return new (Arena) til::Undefined(UO);
264}
265
266
267til::SExpr *SExprBuilder::translateBinOp(til::TIL_BinaryOpcode Op,
268                                         const BinaryOperator *BO,
269                                         CallingContext *Ctx, bool Reverse) {
270   til::SExpr *E0 = translate(BO->getLHS(), Ctx);
271   til::SExpr *E1 = translate(BO->getRHS(), Ctx);
272   if (Reverse)
273     return new (Arena) til::BinaryOp(Op, E1, E0);
274   else
275     return new (Arena) til::BinaryOp(Op, E0, E1);
276}
277
278
279til::SExpr *SExprBuilder::translateBinAssign(til::TIL_BinaryOpcode Op,
280                                             const BinaryOperator *BO,
281                                             CallingContext *Ctx,
282                                             bool Assign) {
283  const Expr *LHS = BO->getLHS();
284  const Expr *RHS = BO->getRHS();
285  til::SExpr *E0 = translate(LHS, Ctx);
286  til::SExpr *E1 = translate(RHS, Ctx);
287
288  const ValueDecl *VD = nullptr;
289  til::SExpr *CV = nullptr;
290  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(LHS)) {
291    VD = DRE->getDecl();
292    CV = lookupVarDecl(VD);
293  }
294
295  if (!Assign) {
296    til::SExpr *Arg = CV ? CV : new (Arena) til::Load(E0);
297    E1 = new (Arena) til::BinaryOp(Op, Arg, E1);
298    E1 = addStatement(E1, nullptr, VD);
299  }
300  if (VD && CV)
301    return updateVarDecl(VD, E1);
302  return new (Arena) til::Store(E0, E1);
303}
304
305
306til::SExpr *SExprBuilder::translateBinaryOperator(const BinaryOperator *BO,
307                                                  CallingContext *Ctx) {
308  switch (BO->getOpcode()) {
309  case BO_PtrMemD:
310  case BO_PtrMemI:
311    return new (Arena) til::Undefined(BO);
312
313  case BO_Mul:  return translateBinOp(til::BOP_Mul, BO, Ctx);
314  case BO_Div:  return translateBinOp(til::BOP_Div, BO, Ctx);
315  case BO_Rem:  return translateBinOp(til::BOP_Rem, BO, Ctx);
316  case BO_Add:  return translateBinOp(til::BOP_Add, BO, Ctx);
317  case BO_Sub:  return translateBinOp(til::BOP_Sub, BO, Ctx);
318  case BO_Shl:  return translateBinOp(til::BOP_Shl, BO, Ctx);
319  case BO_Shr:  return translateBinOp(til::BOP_Shr, BO, Ctx);
320  case BO_LT:   return translateBinOp(til::BOP_Lt,  BO, Ctx);
321  case BO_GT:   return translateBinOp(til::BOP_Lt,  BO, Ctx, true);
322  case BO_LE:   return translateBinOp(til::BOP_Leq, BO, Ctx);
323  case BO_GE:   return translateBinOp(til::BOP_Leq, BO, Ctx, true);
324  case BO_EQ:   return translateBinOp(til::BOP_Eq,  BO, Ctx);
325  case BO_NE:   return translateBinOp(til::BOP_Neq, BO, Ctx);
326  case BO_And:  return translateBinOp(til::BOP_BitAnd,   BO, Ctx);
327  case BO_Xor:  return translateBinOp(til::BOP_BitXor,   BO, Ctx);
328  case BO_Or:   return translateBinOp(til::BOP_BitOr,    BO, Ctx);
329  case BO_LAnd: return translateBinOp(til::BOP_LogicAnd, BO, Ctx);
330  case BO_LOr:  return translateBinOp(til::BOP_LogicOr,  BO, Ctx);
331
332  case BO_Assign:    return translateBinAssign(til::BOP_Eq,  BO, Ctx, true);
333  case BO_MulAssign: return translateBinAssign(til::BOP_Mul, BO, Ctx);
334  case BO_DivAssign: return translateBinAssign(til::BOP_Div, BO, Ctx);
335  case BO_RemAssign: return translateBinAssign(til::BOP_Rem, BO, Ctx);
336  case BO_AddAssign: return translateBinAssign(til::BOP_Add, BO, Ctx);
337  case BO_SubAssign: return translateBinAssign(til::BOP_Sub, BO, Ctx);
338  case BO_ShlAssign: return translateBinAssign(til::BOP_Shl, BO, Ctx);
339  case BO_ShrAssign: return translateBinAssign(til::BOP_Shr, BO, Ctx);
340  case BO_AndAssign: return translateBinAssign(til::BOP_BitAnd, BO, Ctx);
341  case BO_XorAssign: return translateBinAssign(til::BOP_BitXor, BO, Ctx);
342  case BO_OrAssign:  return translateBinAssign(til::BOP_BitOr,  BO, Ctx);
343
344  case BO_Comma:
345    // The clang CFG should have already processed both sides.
346    return translate(BO->getRHS(), Ctx);
347  }
348  return new (Arena) til::Undefined(BO);
349}
350
351
352til::SExpr *SExprBuilder::translateCastExpr(const CastExpr *CE,
353                                            CallingContext *Ctx) {
354  clang::CastKind K = CE->getCastKind();
355  switch (K) {
356  case CK_LValueToRValue: {
357    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
358      til::SExpr *E0 = lookupVarDecl(DRE->getDecl());
359      if (E0)
360        return E0;
361    }
362    til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
363    return new (Arena) til::Load(E0);
364  }
365  case CK_NoOp:
366  case CK_DerivedToBase:
367  case CK_UncheckedDerivedToBase:
368  case CK_ArrayToPointerDecay:
369  case CK_FunctionToPointerDecay: {
370    til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
371    return E0;
372  }
373  default: {
374    // FIXME: handle different kinds of casts.
375    til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
376    return new (Arena) til::Cast(til::CAST_none, E0);
377  }
378  }
379}
380
381
382til::SExpr *
383SExprBuilder::translateArraySubscriptExpr(const ArraySubscriptExpr *E,
384                                          CallingContext *Ctx) {
385  til::SExpr *E0 = translate(E->getBase(), Ctx);
386  til::SExpr *E1 = translate(E->getIdx(), Ctx);
387  return new (Arena) til::ArrayIndex(E0, E1);
388}
389
390
391til::SExpr *
392SExprBuilder::translateConditionalOperator(const ConditionalOperator *C,
393                                           CallingContext *Ctx) {
394  return new (Arena) til::Undefined(C);
395}
396
397
398til::SExpr *SExprBuilder::translateBinaryConditionalOperator(
399    const BinaryConditionalOperator *C, CallingContext *Ctx) {
400  return new (Arena) til::Undefined(C);
401}
402
403
404til::SExpr *
405SExprBuilder::translateDeclStmt(const DeclStmt *S, CallingContext *Ctx) {
406  DeclGroupRef DGrp = S->getDeclGroup();
407  for (DeclGroupRef::iterator I = DGrp.begin(), E = DGrp.end(); I != E; ++I) {
408    if (VarDecl *VD = dyn_cast_or_null<VarDecl>(*I)) {
409      Expr *E = VD->getInit();
410      til::SExpr* SE = translate(E, Ctx);
411
412      // Add local variables with trivial type to the variable map
413      QualType T = VD->getType();
414      if (T.isTrivialType(VD->getASTContext())) {
415        return addVarDecl(VD, SE);
416      }
417      else {
418        // TODO: add alloca
419      }
420    }
421  }
422  return nullptr;
423}
424
425
426
427// If (E) is non-trivial, then add it to the current basic block, and
428// update the statement map so that S refers to E.  Returns a new variable
429// that refers to E.
430// If E is trivial returns E.
431til::SExpr *SExprBuilder::addStatement(til::SExpr* E, const Stmt *S,
432                                       const ValueDecl *VD) {
433  if (!E)
434    return nullptr;
435  if (til::ThreadSafetyTIL::isTrivial(E))
436    return E;
437
438  til::Variable *V = new (Arena) til::Variable(E, VD);
439  CurrentInstructions.push_back(V);
440  if (S)
441    insertStmt(S, V);
442  return V;
443}
444
445
446// Returns the current value of VD, if known, and nullptr otherwise.
447til::SExpr *SExprBuilder::lookupVarDecl(const ValueDecl *VD) {
448  auto It = LVarIdxMap.find(VD);
449  if (It != LVarIdxMap.end()) {
450    assert(CurrentLVarMap[It->second].first == VD);
451    return CurrentLVarMap[It->second].second;
452  }
453  return nullptr;
454}
455
456
457// if E is a til::Variable, update its clangDecl.
458inline void maybeUpdateVD(til::SExpr *E, const ValueDecl *VD) {
459  if (!E)
460    return;
461  if (til::Variable *V = dyn_cast<til::Variable>(E)) {
462    if (!V->clangDecl())
463      V->setClangDecl(VD);
464  }
465}
466
467// Adds a new variable declaration.
468til::SExpr *SExprBuilder::addVarDecl(const ValueDecl *VD, til::SExpr *E) {
469  maybeUpdateVD(E, VD);
470  LVarIdxMap.insert(std::make_pair(VD, CurrentLVarMap.size()));
471  CurrentLVarMap.makeWritable();
472  CurrentLVarMap.push_back(std::make_pair(VD, E));
473  return E;
474}
475
476
477// Updates a current variable declaration.  (E.g. by assignment)
478til::SExpr *SExprBuilder::updateVarDecl(const ValueDecl *VD, til::SExpr *E) {
479  maybeUpdateVD(E, VD);
480  auto It = LVarIdxMap.find(VD);
481  if (It == LVarIdxMap.end()) {
482    til::SExpr *Ptr = new (Arena) til::LiteralPtr(VD);
483    til::SExpr *St  = new (Arena) til::Store(Ptr, E);
484    return St;
485  }
486  CurrentLVarMap.makeWritable();
487  CurrentLVarMap.elem(It->second).second = E;
488  return E;
489}
490
491
492// Make a Phi node in the current block for the i^th variable in CurrentVarMap.
493// If E != null, sets Phi[CurrentBlockInfo->ArgIndex] = E.
494// If E == null, this is a backedge and will be set later.
495void SExprBuilder::makePhiNodeVar(unsigned i, unsigned NPreds, til::SExpr *E) {
496  unsigned ArgIndex = CurrentBlockInfo->ProcessedPredecessors;
497  assert(ArgIndex > 0 && ArgIndex < NPreds);
498
499  til::Variable *V = dyn_cast<til::Variable>(CurrentLVarMap[i].second);
500  if (V && V->getBlockID() == CurrentBB->blockID()) {
501    // We already have a Phi node in the current block,
502    // so just add the new variable to the Phi node.
503    til::Phi *Ph = dyn_cast<til::Phi>(V->definition());
504    assert(Ph && "Expecting Phi node.");
505    if (E)
506      Ph->values()[ArgIndex] = E;
507    return;
508  }
509
510  // Make a new phi node: phi(..., E)
511  // All phi args up to the current index are set to the current value.
512  til::SExpr *CurrE = CurrentLVarMap[i].second;
513  til::Phi *Ph = new (Arena) til::Phi(Arena, NPreds);
514  Ph->values().setValues(NPreds, nullptr);
515  for (unsigned PIdx = 0; PIdx < ArgIndex; ++PIdx)
516    Ph->values()[PIdx] = CurrE;
517  if (E)
518    Ph->values()[ArgIndex] = E;
519  // If E is from a back-edge, or either E or CurrE are incomplete, then
520  // mark this node as incomplete; we may need to remove it later.
521  if (!E || isIncompleteVar(E) || isIncompleteVar(CurrE)) {
522    Ph->setStatus(til::Phi::PH_Incomplete);
523  }
524
525  // Add Phi node to current block, and update CurrentLVarMap[i]
526  auto *Var = new (Arena) til::Variable(Ph, CurrentLVarMap[i].first);
527  CurrentArguments.push_back(Var);
528  if (Ph->status() == til::Phi::PH_Incomplete)
529    IncompleteArgs.push_back(Var);
530
531  CurrentLVarMap.makeWritable();
532  CurrentLVarMap.elem(i).second = Var;
533}
534
535
536// Merge values from Map into the current variable map.
537// This will construct Phi nodes in the current basic block as necessary.
538void SExprBuilder::mergeEntryMap(LVarDefinitionMap Map) {
539  assert(CurrentBlockInfo && "Not processing a block!");
540
541  if (!CurrentLVarMap.valid()) {
542    // Steal Map, using copy-on-write.
543    CurrentLVarMap = std::move(Map);
544    return;
545  }
546  if (CurrentLVarMap.sameAs(Map))
547    return;  // Easy merge: maps from different predecessors are unchanged.
548
549  unsigned NPreds = CurrentBB->numPredecessors();
550  unsigned ESz = CurrentLVarMap.size();
551  unsigned MSz = Map.size();
552  unsigned Sz  = std::min(ESz, MSz);
553
554  for (unsigned i=0; i<Sz; ++i) {
555    if (CurrentLVarMap[i].first != Map[i].first) {
556      // We've reached the end of variables in common.
557      CurrentLVarMap.makeWritable();
558      CurrentLVarMap.downsize(i);
559      break;
560    }
561    if (CurrentLVarMap[i].second != Map[i].second)
562      makePhiNodeVar(i, NPreds, Map[i].second);
563  }
564  if (ESz > MSz) {
565    CurrentLVarMap.makeWritable();
566    CurrentLVarMap.downsize(Map.size());
567  }
568}
569
570
571// Merge a back edge into the current variable map.
572// This will create phi nodes for all variables in the variable map.
573void SExprBuilder::mergeEntryMapBackEdge() {
574  // We don't have definitions for variables on the backedge, because we
575  // haven't gotten that far in the CFG.  Thus, when encountering a back edge,
576  // we conservatively create Phi nodes for all variables.  Unnecessary Phi
577  // nodes will be marked as incomplete, and stripped out at the end.
578  //
579  // An Phi node is unnecessary if it only refers to itself and one other
580  // variable, e.g. x = Phi(y, y, x)  can be reduced to x = y.
581
582  assert(CurrentBlockInfo && "Not processing a block!");
583
584  if (CurrentBlockInfo->HasBackEdges)
585    return;
586  CurrentBlockInfo->HasBackEdges = true;
587
588  CurrentLVarMap.makeWritable();
589  unsigned Sz = CurrentLVarMap.size();
590  unsigned NPreds = CurrentBB->numPredecessors();
591
592  for (unsigned i=0; i < Sz; ++i) {
593    makePhiNodeVar(i, NPreds, nullptr);
594  }
595}
596
597
598// Update the phi nodes that were initially created for a back edge
599// once the variable definitions have been computed.
600// I.e., merge the current variable map into the phi nodes for Blk.
601void SExprBuilder::mergePhiNodesBackEdge(const CFGBlock *Blk) {
602  til::BasicBlock *BB = lookupBlock(Blk);
603  unsigned ArgIndex = BBInfo[Blk->getBlockID()].ProcessedPredecessors;
604  assert(ArgIndex > 0 && ArgIndex < BB->numPredecessors());
605
606  for (til::Variable *V : BB->arguments()) {
607    til::Phi *Ph = dyn_cast_or_null<til::Phi>(V->definition());
608    assert(Ph && "Expecting Phi Node.");
609    assert(Ph->values()[ArgIndex] == nullptr && "Wrong index for back edge.");
610    assert(V->clangDecl() && "No local variable for Phi node.");
611
612    til::SExpr *E = lookupVarDecl(V->clangDecl());
613    assert(E && "Couldn't find local variable for Phi node.");
614
615    Ph->values()[ArgIndex] = E;
616  }
617}
618
619void SExprBuilder::enterCFG(CFG *Cfg, const NamedDecl *D,
620                            const CFGBlock *First) {
621  // Perform initial setup operations.
622  unsigned NBlocks = Cfg->getNumBlockIDs();
623  Scfg = new (Arena) til::SCFG(Arena, NBlocks);
624
625  // allocate all basic blocks immediately, to handle forward references.
626  BBInfo.resize(NBlocks);
627  BlockMap.resize(NBlocks, nullptr);
628  // create map from clang blockID to til::BasicBlocks
629  for (auto *B : *Cfg) {
630    auto *BB = new (Arena) til::BasicBlock(Arena);
631    BB->reserveInstructions(B->size());
632    BlockMap[B->getBlockID()] = BB;
633  }
634  CallCtx.reset(new SExprBuilder::CallingContext(D));
635
636  CurrentBB = lookupBlock(&Cfg->getEntry());
637  auto Parms = isa<ObjCMethodDecl>(D) ? cast<ObjCMethodDecl>(D)->parameters()
638                                      : cast<FunctionDecl>(D)->parameters();
639  for (auto *Pm : Parms) {
640    QualType T = Pm->getType();
641    if (!T.isTrivialType(Pm->getASTContext()))
642      continue;
643
644    // Add parameters to local variable map.
645    // FIXME: right now we emulate params with loads; that should be fixed.
646    til::SExpr *Lp = new (Arena) til::LiteralPtr(Pm);
647    til::SExpr *Ld = new (Arena) til::Load(Lp);
648    til::SExpr *V  = addStatement(Ld, nullptr, Pm);
649    addVarDecl(Pm, V);
650  }
651}
652
653
654void SExprBuilder::enterCFGBlock(const CFGBlock *B) {
655  // Intialize TIL basic block and add it to the CFG.
656  CurrentBB = lookupBlock(B);
657  CurrentBB->reservePredecessors(B->pred_size());
658  Scfg->add(CurrentBB);
659
660  CurrentBlockInfo = &BBInfo[B->getBlockID()];
661
662  // CurrentLVarMap is moved to ExitMap on block exit.
663  // FIXME: the entry block will hold function parameters.
664  // assert(!CurrentLVarMap.valid() && "CurrentLVarMap already initialized.");
665}
666
667
668void SExprBuilder::handlePredecessor(const CFGBlock *Pred) {
669  // Compute CurrentLVarMap on entry from ExitMaps of predecessors
670
671  CurrentBB->addPredecessor(BlockMap[Pred->getBlockID()]);
672  BlockInfo *PredInfo = &BBInfo[Pred->getBlockID()];
673  assert(PredInfo->UnprocessedSuccessors > 0);
674
675  if (--PredInfo->UnprocessedSuccessors == 0)
676    mergeEntryMap(std::move(PredInfo->ExitMap));
677  else
678    mergeEntryMap(PredInfo->ExitMap.clone());
679
680  ++CurrentBlockInfo->ProcessedPredecessors;
681}
682
683
684void SExprBuilder::handlePredecessorBackEdge(const CFGBlock *Pred) {
685  mergeEntryMapBackEdge();
686}
687
688
689void SExprBuilder::enterCFGBlockBody(const CFGBlock *B) {
690  // The merge*() methods have created arguments.
691  // Push those arguments onto the basic block.
692  CurrentBB->arguments().reserve(
693    static_cast<unsigned>(CurrentArguments.size()), Arena);
694  for (auto *V : CurrentArguments)
695    CurrentBB->addArgument(V);
696}
697
698
699void SExprBuilder::handleStatement(const Stmt *S) {
700  til::SExpr *E = translate(S, CallCtx.get());
701  addStatement(E, S);
702}
703
704
705void SExprBuilder::handleDestructorCall(const VarDecl *VD,
706                                        const CXXDestructorDecl *DD) {
707  til::SExpr *Sf = new (Arena) til::LiteralPtr(VD);
708  til::SExpr *Dr = new (Arena) til::LiteralPtr(DD);
709  til::SExpr *Ap = new (Arena) til::Apply(Dr, Sf);
710  til::SExpr *E = new (Arena) til::Call(Ap);
711  addStatement(E, nullptr);
712}
713
714
715
716void SExprBuilder::exitCFGBlockBody(const CFGBlock *B) {
717  CurrentBB->instructions().reserve(
718    static_cast<unsigned>(CurrentInstructions.size()), Arena);
719  for (auto *V : CurrentInstructions)
720    CurrentBB->addInstruction(V);
721
722  // Create an appropriate terminator
723  unsigned N = B->succ_size();
724  auto It = B->succ_begin();
725  if (N == 1) {
726    til::BasicBlock *BB = *It ? lookupBlock(*It) : nullptr;
727    // TODO: set index
728    unsigned Idx = BB ? BB->findPredecessorIndex(CurrentBB) : 0;
729    til::SExpr *Tm = new (Arena) til::Goto(BB, Idx);
730    CurrentBB->setTerminator(Tm);
731  }
732  else if (N == 2) {
733    til::SExpr *C = translate(B->getTerminatorCondition(true), CallCtx.get());
734    til::BasicBlock *BB1 = *It ? lookupBlock(*It) : nullptr;
735    ++It;
736    til::BasicBlock *BB2 = *It ? lookupBlock(*It) : nullptr;
737    unsigned Idx1 = BB1 ? BB1->findPredecessorIndex(CurrentBB) : 0;
738    unsigned Idx2 = BB2 ? BB2->findPredecessorIndex(CurrentBB) : 0;
739    til::SExpr *Tm = new (Arena) til::Branch(C, BB1, BB2, Idx1, Idx2);
740    CurrentBB->setTerminator(Tm);
741  }
742}
743
744
745void SExprBuilder::handleSuccessor(const CFGBlock *Succ) {
746  ++CurrentBlockInfo->UnprocessedSuccessors;
747}
748
749
750void SExprBuilder::handleSuccessorBackEdge(const CFGBlock *Succ) {
751  mergePhiNodesBackEdge(Succ);
752  ++BBInfo[Succ->getBlockID()].ProcessedPredecessors;
753}
754
755
756void SExprBuilder::exitCFGBlock(const CFGBlock *B) {
757  CurrentArguments.clear();
758  CurrentInstructions.clear();
759  CurrentBlockInfo->ExitMap = std::move(CurrentLVarMap);
760  CurrentBB = nullptr;
761  CurrentBlockInfo = nullptr;
762}
763
764
765void SExprBuilder::exitCFG(const CFGBlock *Last) {
766  for (auto *V : IncompleteArgs) {
767    til::Phi *Ph = dyn_cast<til::Phi>(V->definition());
768    if (Ph && Ph->status() == til::Phi::PH_Incomplete)
769      simplifyIncompleteArg(V, Ph);
770  }
771
772  CurrentArguments.clear();
773  CurrentInstructions.clear();
774  IncompleteArgs.clear();
775}
776
777
778
779class TILPrinter : public til::PrettyPrinter<TILPrinter, llvm::raw_ostream> {};
780
781
782void printSCFG(CFGWalker &Walker) {
783  llvm::BumpPtrAllocator Bpa;
784  til::MemRegionRef Arena(&Bpa);
785  SExprBuilder builder(Arena);
786  til::SCFG *Cfg = builder.buildCFG(Walker);
787  TILPrinter::print(Cfg, llvm::errs());
788}
789
790
791
792} // end namespace threadSafety
793
794} // end namespace clang
795