This revision was automatically updated to reflect the committed changes.
Closed by commit rL328173: Improve -Winfinite-recursion (authored by CodaFi,
committed by ).
Herald added a subscriber: llvm-commits.
Changed prior to commit:
https://reviews.llvm.org/D43737?vs=139325&id=139408#toc
Repository:
rL LLVM
https://reviews.llvm.org/D43737
Files:
cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
cfe/trunk/test/SemaCXX/warn-infinite-recursion.cpp
Index: cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
===================================================================
--- cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
+++ cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
@@ -200,60 +200,41 @@
return false;
}
-// All blocks are in one of three states. States are ordered so that blocks
-// can only move to higher states.
-enum RecursiveState {
- FoundNoPath,
- FoundPath,
- FoundPathWithNoRecursiveCall
-};
-
-// Returns true if there exists a path to the exit block and every path
-// to the exit block passes through a call to FD.
+// Returns true if every path from the entry block passes through a call to FD.
static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg) {
+ llvm::SmallPtrSet<CFGBlock *, 16> Visited;
+ llvm::SmallVector<CFGBlock *, 16> WorkList;
+ // Keep track of whether we found at least one recursive path.
+ bool foundRecursion = false;
const unsigned ExitID = cfg->getExit().getBlockID();
- // Mark all nodes as FoundNoPath, then set the status of the entry block.
- SmallVector<RecursiveState, 16> States(cfg->getNumBlockIDs(), FoundNoPath);
- States[cfg->getEntry().getBlockID()] = FoundPathWithNoRecursiveCall;
+ // Seed the work list with the entry block.
+ WorkList.push_back(&cfg->getEntry());
- // Make the processing stack and seed it with the entry block.
- SmallVector<CFGBlock *, 16> Stack;
- Stack.push_back(&cfg->getEntry());
-
- while (!Stack.empty()) {
- CFGBlock *CurBlock = Stack.back();
- Stack.pop_back();
-
- unsigned ID = CurBlock->getBlockID();
- RecursiveState CurState = States[ID];
-
- if (CurState == FoundPathWithNoRecursiveCall) {
- // Found a path to the exit node without a recursive call.
- if (ExitID == ID)
- return false;
+ while (!WorkList.empty()) {
+ CFGBlock *Block = WorkList.pop_back_val();
- // Only change state if the block has a recursive call.
- if (hasRecursiveCallInPath(FD, *CurBlock))
- CurState = FoundPath;
- }
+ for (auto I = Block->succ_begin(), E = Block->succ_end(); I != E; ++I) {
+ if (CFGBlock *SuccBlock = *I) {
+ if (!Visited.insert(SuccBlock).second)
+ continue;
- // Loop over successor blocks and add them to the Stack if their state
- // changes.
- for (auto I = CurBlock->succ_begin(), E = CurBlock->succ_end(); I != E; ++I)
- if (*I) {
- unsigned next_ID = (*I)->getBlockID();
- if (States[next_ID] < CurState) {
- States[next_ID] = CurState;
- Stack.push_back(*I);
+ // Found a path to the exit node without a recursive call.
+ if (ExitID == SuccBlock->getBlockID())
+ return false;
+
+ // If the successor block contains a recursive call, end analysis there.
+ if (hasRecursiveCallInPath(FD, *SuccBlock)) {
+ foundRecursion = true;
+ continue;
}
+
+ WorkList.push_back(SuccBlock);
}
+ }
}
-
- // Return true if the exit node is reachable, and only reachable through
- // a recursive call.
- return States[ExitID] == FoundPath;
+ return foundRecursion;
}
static void checkRecursiveFunction(Sema &S, const FunctionDecl *FD,
@@ -269,10 +250,6 @@
CFG *cfg = AC.getCFG();
if (!cfg) return;
- // If the exit block is unreachable, skip processing the function.
- if (cfg->getExit().pred_empty())
- return;
-
// Emit diagnostic if a recursive function call is detected for all paths.
if (checkForRecursiveFunctionCall(FD, cfg))
S.Diag(Body->getLocStart(), diag::warn_infinite_recursive_function);
Index: cfe/trunk/test/SemaCXX/warn-infinite-recursion.cpp
===================================================================
--- cfe/trunk/test/SemaCXX/warn-infinite-recursion.cpp
+++ cfe/trunk/test/SemaCXX/warn-infinite-recursion.cpp
@@ -29,8 +29,7 @@
void e() { f(); }
void f() { e(); }
-// Don't warn on infinite loops
-void g() {
+void g() { // expected-warning{{call itself}}
while (true)
g();
@@ -54,6 +53,19 @@
return 5 + j();
}
+void k() { // expected-warning{{call itself}}
+ while(true) {
+ k();
+ }
+}
+
+// Don't warn on infinite loops
+void l() {
+ while (true) {}
+
+ l();
+}
+
class S {
static void a();
void b();
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