diff options
Diffstat (limited to 'clang/lib/Analysis/ReachableCode.cpp')
| -rw-r--r-- | clang/lib/Analysis/ReachableCode.cpp | 35 |
1 files changed, 27 insertions, 8 deletions
diff --git a/clang/lib/Analysis/ReachableCode.cpp b/clang/lib/Analysis/ReachableCode.cpp index 797e02e..4a19280 100644 --- a/clang/lib/Analysis/ReachableCode.cpp +++ b/clang/lib/Analysis/ReachableCode.cpp @@ -337,12 +337,6 @@ void DeadCodeScan::reportDeadCode(const CFGBlock *B, if (isTrivialReturnPrecededByNoReturn(B, S)) return; - // Was this an unreachable 'default' case? Such cases are covered - // by -Wcovered-switch-default, if the user so desires. - const Stmt *Label = B->getLabel(); - if (Label && isa<DefaultStmt>(Label)) - return; - SourceRange R1, R2; SourceLocation Loc = GetUnreachableLoc(S, R1, R2); CB.HandleUnreachable(Loc, R1, R2); @@ -374,8 +368,32 @@ unsigned ScanReachableFromBlock(const CFGBlock *Start, // Look at the successors and mark then reachable. for (CFGBlock::const_succ_iterator I = item->succ_begin(), - E = item->succ_end(); I != E; ++I) - if (const CFGBlock *B = *I) { + E = item->succ_end(); I != E; ++I) { + const CFGBlock *B = *I; + if (!B) { + // + // For switch statements, treat all cases as being reachable. + // There are many cases where a switch can contain values that + // are not in an enumeration but they are still reachable because + // other values are possible. + // + // Note that this is quite conservative. If one saw: + // + // switch (1) { + // case 2: ... + // + // we should be able to say that 'case 2' is unreachable. To do + // this we can either put more heuristics here, or possibly retain + // that information in the CFG itself. + // + if (const CFGBlock *UB = I->getPossiblyUnreachableBlock()) { + const Stmt *Label = UB->getLabel(); + if (Label && isa<SwitchCase>(Label)) { + B = UB; + } + } + } + if (B) { unsigned blockID = B->getBlockID(); if (!Reachable[blockID]) { Reachable.set(blockID); @@ -383,6 +401,7 @@ unsigned ScanReachableFromBlock(const CFGBlock *Start, ++count; } } + } } return count; } |