While reading LLVM API docs, I have noticed a lot of plain
"new"/"delete"
statements, and lots of bare pointers ("Value* = foo.getSomeValue()"
etc.).
How exactly LLVM manages it's own memory? Who is responsible for
allocating/deallocating things? Why smart pointers are not used?
Thanks in advance. I hope I haven't missed some basic chapter about this
in tutorial :-)
--
Regards, Gregory.
On Nov 10, 2008, at 6:11 AM, Gregory Petrosyan wrote:> While reading LLVM API docs, I have noticed a lot of plain > "new"/"delete" > statements, and lots of bare pointers ("Value* = foo.getSomeValue()" > etc.). > > 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 +delete.> Thanks in advance. I hope I haven't missed some basic chapter about > this > 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? -Chris
2008/11/11 Chris Lattner <clattner at apple.com>:> 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 > +delete.Thanks once again.> 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?I'll try. -- Regards, Gregory.