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if basic blocks are destroyed while there are *just* BlockAddress' hanging
around, then zap them. This is analogous to dangling constantexprs hanging off functions. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85627 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -58,6 +58,24 @@ BasicBlock::BasicBlock(LLVMContext &C, const Twine &Name, Function *NewParent,
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BasicBlock::~BasicBlock() {
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// If the address of the block is taken and it is being deleted (e.g. because
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// it is dead), this means that there is either a dangling constant expr
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// hanging off the block, or an undefined use of the block (source code
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// expecting the address of a label to keep the block alive even though there
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// is no indirect branch). Handle these cases by zapping the BlockAddress
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// nodes. There are no other possible uses at this point.
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if (hasAddressTaken()) {
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assert(!use_empty() && "There should be at least one blockaddress!");
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Constant *Replacement =
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ConstantInt::get(llvm::Type::getInt32Ty(getContext()), 1);
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while (!use_empty()) {
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BlockAddress *BA = cast<BlockAddress>(use_back());
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BA->replaceAllUsesWith(ConstantExpr::getIntToPtr(Replacement,
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BA->getType()));
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BA->destroyConstant();
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}
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}
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assert(getParent() == 0 && "BasicBlock still linked into the program!");
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dropAllReferences();
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InstList.clear();
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@ -21,5 +21,10 @@ BB1: ; preds = %0, %0
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}
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define void @test4() {
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entry:
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br label %return
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return:
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ret void
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}
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@test4g = global i8* blockaddress(@test4, %return)
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