Zhongxing Xu | 7c9624b | 2009-12-08 09:07:59 +0000 | [diff] [blame] | 1 | //=== BuiltinFunctionChecker.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 | // This checker evaluates clang builtin functions. |
| 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #include "GRExprEngineInternalChecks.h" |
| 15 | #include "clang/Analysis/PathSensitive/Checker.h" |
| 16 | #include "clang/Basic/Builtins.h" |
| 17 | #include "llvm/ADT/StringSwitch.h" |
| 18 | |
| 19 | using namespace clang; |
| 20 | |
| 21 | namespace { |
| 22 | |
| 23 | class BuiltinFunctionChecker : public Checker { |
| 24 | public: |
| 25 | static void *getTag() { static int tag = 0; return &tag; } |
| 26 | virtual bool EvalCallExpr(CheckerContext &C, const CallExpr *CE); |
| 27 | }; |
| 28 | |
| 29 | } |
| 30 | |
| 31 | void clang::RegisterBuiltinFunctionChecker(GRExprEngine &Eng) { |
| 32 | Eng.registerCheck(new BuiltinFunctionChecker()); |
| 33 | } |
| 34 | |
| 35 | bool BuiltinFunctionChecker::EvalCallExpr(CheckerContext &C,const CallExpr *CE){ |
| 36 | const GRState *state = C.getState(); |
| 37 | const Expr *Callee = CE->getCallee(); |
| 38 | SVal L = state->getSVal(Callee); |
| 39 | const FunctionDecl *FD = L.getAsFunctionDecl(); |
| 40 | |
| 41 | if (!FD) |
| 42 | return false; |
| 43 | |
| 44 | unsigned id = FD->getBuiltinID(); |
| 45 | |
| 46 | if (!id) |
| 47 | return false; |
| 48 | |
| 49 | switch (id) { |
| 50 | case Builtin::BI__builtin_expect: { |
| 51 | // For __builtin_expect, just return the value of the subexpression. |
| 52 | assert (CE->arg_begin() != CE->arg_end()); |
| 53 | SVal X = state->getSVal(*(CE->arg_begin())); |
| 54 | C.GenerateNode(state->BindExpr(CE, X)); |
| 55 | return true; |
| 56 | } |
| 57 | |
| 58 | case Builtin::BI__builtin_alloca: { |
| 59 | // FIXME: Refactor into StoreManager itself? |
| 60 | MemRegionManager& RM = C.getStoreManager().getRegionManager(); |
| 61 | const MemRegion* R = |
| 62 | RM.getAllocaRegion(CE, C.getNodeBuilder().getCurrentBlockCount(), |
| 63 | C.getPredecessor()->getLocationContext()); |
| 64 | |
| 65 | // Set the extent of the region in bytes. This enables us to use the |
| 66 | // SVal of the argument directly. If we save the extent in bits, we |
| 67 | // cannot represent values like symbol*8. |
| 68 | SVal Extent = state->getSVal(*(CE->arg_begin())); |
| 69 | state = C.getStoreManager().setExtent(state, R, Extent); |
| 70 | C.GenerateNode(state->BindExpr(CE, loc::MemRegionVal(R))); |
| 71 | return true; |
| 72 | } |
| 73 | } |
| 74 | |
| 75 | return false; |
| 76 | } |