[CodeExtractor] Prevent extraction of block involving blockaddress
BlockAddress are only valid within their function context, which does not
interact well with CodeExtractor. Detect this case and prevent it.
Differential Revision: https://reviews.llvm.org/D33839
llvm-svn: 306448
diff --git a/llvm/lib/Transforms/Utils/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index 5d57ed9..30d8856 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -59,6 +59,33 @@
// Landing pads must be in the function where they were inserted for cleanup.
if (BB.isEHPad())
return false;
+ // taking the address of a basic block moved to another function is illegal
+ if (BB.hasAddressTaken())
+ return false;
+
+ // don't hoist code that uses another basicblock address, as it's likely to
+ // lead to unexpected behavior, like cross-function jumps
+ SmallPtrSet<User const *, 16> Visited;
+ SmallVector<User const *, 16> ToVisit;
+
+ for (Instruction const &Inst : BB)
+ ToVisit.push_back(&Inst);
+
+ while (!ToVisit.empty()) {
+ User const *Curr = ToVisit.pop_back_val();
+ if (!Visited.insert(Curr).second)
+ continue;
+ if (isa<BlockAddress const>(Curr))
+ return false; // even a reference to self is likely to be not compatible
+
+ if (isa<Instruction>(Curr) && cast<Instruction>(Curr)->getParent() != &BB)
+ continue;
+
+ for (auto const &U : Curr->operands()) {
+ if (auto *UU = dyn_cast<User>(U))
+ ToVisit.push_back(UU);
+ }
+ }
// Don't hoist code containing allocas, invokes, or vastarts.
for (BasicBlock::const_iterator I = BB.begin(), E = BB.end(); I != E; ++I) {