[LLVMdev] LLVM C++ API memory management
clattner at apple.com
Mon Nov 10 13:29:52 PST 2008
On Nov 10, 2008, at 6:11 AM, Gregory Petrosyan wrote:
> While reading LLVM API docs, I have noticed a lot of plain
> statements, and lots of bare pointers ("Value* = foo.getSomeValue()"
> How exactly LLVM manages it's own memory? Who is responsible for
> allocating/deallocating things? Why smart pointers are not used?
The ownership model is very simple. We have a simple structured
system (e.g. module is a list of functions, function is a list of
blocks, blocks are a list of instructions). When a node is inserted
into a parent container (e.g. an instruction in a basic block) then
the parent owns the node.
This means that if you create an instruction and insert it into a
block, you're fine. If you remove an instruction from a block, you
have to either reinsert it or delete it. The "remove" methods remove
a node from its parent and returns it, the "erase" methods do a remove
> Thanks in advance. I hope I haven't missed some basic chapter about
> in tutorial :-)
Unfortunately this is not really documented anywhere. It would be
really really good to add a section about this in the Programmer's
Manual. Can you write up a patch?
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