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Sema: Avoid a stack overflow on large CFGs 

Large CFGs cause `checkForFunctionCall()` to overflow its stack.  Break
the recursion by manually managing the call stack instead.

Patch by Vedant Kumar!

llvm-svn: 243039
This commit is contained in:
Duncan P. N. Exon Smith 2015-07-23 20:15:50 +00:00
parent f0eafc78e0
commit dccc30a7ef
1 changed files with 24 additions and 16 deletions
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40
clang/lib/Sema/AnalysisBasedWarnings.cpp
View File

@ -207,27 +207,35 @@ static void checkForFunctionCall(Sema &S, const FunctionDecl *FD,
CFGBlock &Block, unsigned ExitID,
llvm::SmallVectorImpl<RecursiveState> &States,
RecursiveState State) {
unsigned ID = Block.getBlockID();
SmallVector<std::pair<CFGBlock *, RecursiveState>, 16> Stack;
Stack.emplace_back(&Block, State);
// A block's state can only move to a higher state.
if (States[ID] >= State)
return;
while (!Stack.empty()) {
CFGBlock &CurBlock = *Stack.back().first;
RecursiveState CurState = Stack.back().second;
Stack.pop_back();
States[ID] = State;
unsigned ID = CurBlock.getBlockID();
if (State == FoundPathWithNoRecursiveCall) {
// Found a path to the exit node without a recursive call.
if (ExitID == ID)
return;
// A block's state can only move to a higher state.
if (States[ID] >= CurState)
continue;
if (hasRecursiveCallInPath(FD, Block))
State = FoundPath;
States[ID] = CurState;
if (CurState == FoundPathWithNoRecursiveCall) {
// Found a path to the exit node without a recursive call.
if (ExitID == ID)
continue;
if (hasRecursiveCallInPath(FD, CurBlock))
CurState = FoundPath;
}
for (auto I = CurBlock.succ_begin(), E = CurBlock.succ_end(); I != E; ++I)
if (*I)
Stack.emplace_back(*I, CurState);
}
for (CFGBlock::succ_iterator I = Block.succ_begin(), E = Block.succ_end();
I != E; ++I)
if (*I)
checkForFunctionCall(S, FD, **I, ExitID, States, State);
}
static void checkRecursiveFunction(Sema &S, const FunctionDecl *FD,