[PATCH] Allocate stack storage for .block_descriptor and captured self.

[Adrian Prantl]

John,

I think there is a bug in the existing code in lib/CodeGen/Blocks.cpp:1181

   unsigned align = getContext().getDeclAlign(variable).getQuantity();

    llvm::AllocaInst *alloca =
      CreateMemTemp(variable->getType(), "block.captured-const");
    alloca->setAlignment(align);

    Builder.CreateStore(capture.getConstant(), alloca, align);

                                                       ^^^^^

The third argument of IRBuilder::CreateStore() is the “volatile” flag.
http://llvm.org/doxygen/classllvm_1_1IRBuilder.html

I assume that “align” is usually nonzero — so it would likely output a "store volatile". Do you think that’s unintentional and it’s safe to replace it with false? Or is the volatile modifier needed here?

Adrian