diff options
| -rw-r--r-- | lib/VMCore/BasicBlock.cpp | 18 | ||||
| -rw-r--r-- | test/Transforms/SimplifyCFG/basictest.ll | 9 |
2 files changed, 25 insertions, 2 deletions
diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp index e8069c0..23d0557 100644 --- a/lib/VMCore/BasicBlock.cpp +++ b/lib/VMCore/BasicBlock.cpp @@ -58,6 +58,24 @@ BasicBlock::BasicBlock(LLVMContext &C, const Twine &Name, Function *NewParent, BasicBlock::~BasicBlock() { + // If the address of the block is taken and it is being deleted (e.g. because + // it is dead), this means that there is either a dangling constant expr + // hanging off the block, or an undefined use of the block (source code + // expecting the address of a label to keep the block alive even though there + // is no indirect branch). Handle these cases by zapping the BlockAddress + // nodes. There are no other possible uses at this point. + if (hasAddressTaken()) { + assert(!use_empty() && "There should be at least one blockaddress!"); + Constant *Replacement = + ConstantInt::get(llvm::Type::getInt32Ty(getContext()), 1); + while (!use_empty()) { + BlockAddress *BA = cast<BlockAddress>(use_back()); + BA->replaceAllUsesWith(ConstantExpr::getIntToPtr(Replacement, + BA->getType())); + BA->destroyConstant(); + } + } + assert(getParent() == 0 && "BasicBlock still linked into the program!"); dropAllReferences(); InstList.clear(); diff --git a/test/Transforms/SimplifyCFG/basictest.ll b/test/Transforms/SimplifyCFG/basictest.ll index 468b6ed..a829e03 100644 --- a/test/Transforms/SimplifyCFG/basictest.ll +++ b/test/Transforms/SimplifyCFG/basictest.ll @@ -21,5 +21,10 @@ BB1: ; preds = %0, %0 } - - +define void @test4() { +entry: + br label %return +return: + ret void +} +@test4g = global i8* blockaddress(@test4, %return) |