Author: szepet Date: Sat Oct 28 05:19:08 2017 New Revision: 316830 URL: http://llvm.org/viewvc/llvm-project?rev=316830&view=rev Log: [analyzer] LoopUnrolling: check the bitwidth of the used numbers (pr34943)
The loop unrolling feature aims to track the maximum possible steps a loop can make. In order to implement this, it investigates the initial value of the counter variable and the bound number. (It has to be known.) These numbers are used as llvm::APInts, however, it was not checked if their bitwidths are the same which lead to some crashes. This revision solves this problem by extending the "shorter" one (to the length of the "longer" one). For the detailed bug report, see: https://bugs.llvm.org/show_bug.cgi?id=34943 Differential Revision: https://reviews.llvm.org/D38922 Modified: cfe/trunk/lib/StaticAnalyzer/Core/LoopUnrolling.cpp cfe/trunk/test/Analysis/loop-unrolling.cpp Modified: cfe/trunk/lib/StaticAnalyzer/Core/LoopUnrolling.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/LoopUnrolling.cpp?rev=316830&r1=316829&r2=316830&view=diff ============================================================================== --- cfe/trunk/lib/StaticAnalyzer/Core/LoopUnrolling.cpp (original) +++ cfe/trunk/lib/StaticAnalyzer/Core/LoopUnrolling.cpp Sat Oct 28 05:19:08 2017 @@ -208,9 +208,16 @@ bool shouldCompletelyUnroll(const Stmt * return false; auto CounterVar = Matches[0].getNodeAs<VarDecl>("initVarName"); - auto BoundNum = Matches[0].getNodeAs<IntegerLiteral>("boundNum")->getValue(); - auto InitNum = Matches[0].getNodeAs<IntegerLiteral>("initNum")->getValue(); + llvm::APInt BoundNum = + Matches[0].getNodeAs<IntegerLiteral>("boundNum")->getValue(); + llvm::APInt InitNum = + Matches[0].getNodeAs<IntegerLiteral>("initNum")->getValue(); auto CondOp = Matches[0].getNodeAs<BinaryOperator>("conditionOperator"); + if (InitNum.getBitWidth() != BoundNum.getBitWidth()) { + InitNum = InitNum.zextOrSelf(BoundNum.getBitWidth()); + BoundNum = BoundNum.zextOrSelf(InitNum.getBitWidth()); + } + if (CondOp->getOpcode() == BO_GE || CondOp->getOpcode() == BO_LE) maxStep = (BoundNum - InitNum + 1).abs().getZExtValue(); else Modified: cfe/trunk/test/Analysis/loop-unrolling.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/loop-unrolling.cpp?rev=316830&r1=316829&r2=316830&view=diff ============================================================================== --- cfe/trunk/test/Analysis/loop-unrolling.cpp (original) +++ cfe/trunk/test/Analysis/loop-unrolling.cpp Sat Oct 28 05:19:08 2017 @@ -373,3 +373,9 @@ int num_steps_over_limit3() { return 0; } + +void pr34943() { + for (int i = 0; i < 6L; ++i) { + clang_analyzer_numTimesReached(); // expected-warning {{6}} + } +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
