diff options
Diffstat (limited to 'llvm/lib/Analysis/Lint.cpp')
| -rw-r--r-- | llvm/lib/Analysis/Lint.cpp | 188 |
1 files changed, 0 insertions, 188 deletions
diff --git a/llvm/lib/Analysis/Lint.cpp b/llvm/lib/Analysis/Lint.cpp index 15acc783f07..b63049c2591 100644 --- a/llvm/lib/Analysis/Lint.cpp +++ b/llvm/lib/Analysis/Lint.cpp @@ -345,13 +345,6 @@ void Lint::visitCallSite(CallSite CS) { visitMemoryReference(I, CS.getArgument(0), MemoryLocation::UnknownSize, 0, nullptr, MemRef::Read | MemRef::Write); break; - - case Intrinsic::eh_begincatch: - visitEHBeginCatch(II); - break; - case Intrinsic::eh_endcatch: - visitEHEndCatch(II); - break; } } @@ -511,187 +504,6 @@ void Lint::visitShl(BinaryOperator &I) { "Undefined result: Shift count out of range", &I); } -static bool -allPredsCameFromLandingPad(BasicBlock *BB, - SmallSet<BasicBlock *, 4> &VisitedBlocks) { - VisitedBlocks.insert(BB); - if (BB->isLandingPad()) - return true; - // If we find a block with no predecessors, the search failed. - if (pred_empty(BB)) - return false; - for (BasicBlock *Pred : predecessors(BB)) { - if (VisitedBlocks.count(Pred)) - continue; - if (!allPredsCameFromLandingPad(Pred, VisitedBlocks)) - return false; - } - return true; -} - -static bool -allSuccessorsReachEndCatch(BasicBlock *BB, BasicBlock::iterator InstBegin, - IntrinsicInst **SecondBeginCatch, - SmallSet<BasicBlock *, 4> &VisitedBlocks) { - VisitedBlocks.insert(BB); - for (BasicBlock::iterator I = InstBegin, E = BB->end(); I != E; ++I) { - IntrinsicInst *IC = dyn_cast<IntrinsicInst>(I); - if (IC && IC->getIntrinsicID() == Intrinsic::eh_endcatch) - return true; - // If we find another begincatch while looking for an endcatch, - // that's also an error. - if (IC && IC->getIntrinsicID() == Intrinsic::eh_begincatch) { - *SecondBeginCatch = IC; - return false; - } - } - - // If we reach a block with no successors while searching, the - // search has failed. - if (succ_empty(BB)) - return false; - // Otherwise, search all of the successors. - for (BasicBlock *Succ : successors(BB)) { - if (VisitedBlocks.count(Succ)) - continue; - if (!allSuccessorsReachEndCatch(Succ, Succ->begin(), SecondBeginCatch, - VisitedBlocks)) - return false; - } - return true; -} - -void Lint::visitEHBeginCatch(IntrinsicInst *II) { - // The checks in this function make a potentially dubious assumption about - // the CFG, namely that any block involved in a catch is only used for the - // catch. This will very likely be true of IR generated by a front end, - // but it may cease to be true, for example, if the IR is run through a - // pass which combines similar blocks. - // - // In general, if we encounter a block the isn't dominated by the catch - // block while we are searching the catch block's successors for a call - // to end catch intrinsic, then it is possible that it will be legal for - // a path through this block to never reach a call to llvm.eh.endcatch. - // An analogous statement could be made about our search for a landing - // pad among the catch block's predecessors. - // - // What is actually required is that no path is possible at runtime that - // reaches a call to llvm.eh.begincatch without having previously visited - // a landingpad instruction and that no path is possible at runtime that - // calls llvm.eh.begincatch and does not subsequently call llvm.eh.endcatch - // (mentally adjusting for the fact that in reality these calls will be - // removed before code generation). - // - // Because this is a lint check, we take a pessimistic approach and warn if - // the control flow is potentially incorrect. - - SmallSet<BasicBlock *, 4> VisitedBlocks; - BasicBlock *CatchBB = II->getParent(); - - // The begin catch must occur in a landing pad block or all paths - // to it must have come from a landing pad. - Assert(allPredsCameFromLandingPad(CatchBB, VisitedBlocks), - "llvm.eh.begincatch may be reachable without passing a landingpad", - II); - - // Reset the visited block list. - VisitedBlocks.clear(); - - IntrinsicInst *SecondBeginCatch = nullptr; - - // This has to be called before it is asserted. Otherwise, the first assert - // below can never be hit. - bool EndCatchFound = allSuccessorsReachEndCatch( - CatchBB, std::next(static_cast<BasicBlock::iterator>(II)), - &SecondBeginCatch, VisitedBlocks); - Assert( - SecondBeginCatch == nullptr, - "llvm.eh.begincatch may be called a second time before llvm.eh.endcatch", - II, SecondBeginCatch); - Assert(EndCatchFound, - "Some paths from llvm.eh.begincatch may not reach llvm.eh.endcatch", - II); -} - -static bool allPredCameFromBeginCatch( - BasicBlock *BB, BasicBlock::reverse_iterator InstRbegin, - IntrinsicInst **SecondEndCatch, SmallSet<BasicBlock *, 4> &VisitedBlocks) { - VisitedBlocks.insert(BB); - // Look for a begincatch in this block. - for (BasicBlock::reverse_iterator RI = InstRbegin, RE = BB->rend(); RI != RE; - ++RI) { - IntrinsicInst *IC = dyn_cast<IntrinsicInst>(&*RI); - if (IC && IC->getIntrinsicID() == Intrinsic::eh_begincatch) - return true; - // If we find another end catch before we find a begin catch, that's - // an error. - if (IC && IC->getIntrinsicID() == Intrinsic::eh_endcatch) { - *SecondEndCatch = IC; - return false; - } - // If we encounter a landingpad instruction, the search failed. - if (isa<LandingPadInst>(*RI)) - return false; - } - // If while searching we find a block with no predeccesors, - // the search failed. - if (pred_empty(BB)) - return false; - // Search any predecessors we haven't seen before. - for (BasicBlock *Pred : predecessors(BB)) { - if (VisitedBlocks.count(Pred)) - continue; - if (!allPredCameFromBeginCatch(Pred, Pred->rbegin(), SecondEndCatch, - VisitedBlocks)) - return false; - } - return true; -} - -void Lint::visitEHEndCatch(IntrinsicInst *II) { - // The check in this function makes a potentially dubious assumption about - // the CFG, namely that any block involved in a catch is only used for the - // catch. This will very likely be true of IR generated by a front end, - // but it may cease to be true, for example, if the IR is run through a - // pass which combines similar blocks. - // - // In general, if we encounter a block the isn't post-dominated by the - // end catch block while we are searching the end catch block's predecessors - // for a call to the begin catch intrinsic, then it is possible that it will - // be legal for a path to reach the end catch block without ever having - // called llvm.eh.begincatch. - // - // What is actually required is that no path is possible at runtime that - // reaches a call to llvm.eh.endcatch without having previously visited - // a call to llvm.eh.begincatch (mentally adjusting for the fact that in - // reality these calls will be removed before code generation). - // - // Because this is a lint check, we take a pessimistic approach and warn if - // the control flow is potentially incorrect. - - BasicBlock *EndCatchBB = II->getParent(); - - // Alls paths to the end catch call must pass through a begin catch call. - - // If llvm.eh.begincatch wasn't called in the current block, we'll use this - // lambda to recursively look for it in predecessors. - SmallSet<BasicBlock *, 4> VisitedBlocks; - IntrinsicInst *SecondEndCatch = nullptr; - - // This has to be called before it is asserted. Otherwise, the first assert - // below can never be hit. - bool BeginCatchFound = - allPredCameFromBeginCatch(EndCatchBB, BasicBlock::reverse_iterator(II), - &SecondEndCatch, VisitedBlocks); - Assert( - SecondEndCatch == nullptr, - "llvm.eh.endcatch may be called a second time after llvm.eh.begincatch", - II, SecondEndCatch); - Assert(BeginCatchFound, - "llvm.eh.endcatch may be reachable without passing llvm.eh.begincatch", - II); -} - static bool isZero(Value *V, const DataLayout &DL, DominatorTree *DT, AssumptionCache *AC) { // Assume undef could be zero. |
