llvm dev - Apr 2010 - [LLVMdev] raw_os_ostream: symbol not found

Hi,

I'm writing some code that prints to std::ostream. However, it seems  
that all of the LLVM objects can only print to llvm::raw_ostream, so I  
can't do this:

void write(std::ostream &out) {
    ...
    for (BasicBlock::iterator i = block->begin(), e = block->end(); i ! 
= e; ++i) {
       Instruction *instruction = i;
       out << *instruction << std::endl;
       ...
    }
    ...
}

I tried working around this problem using the raw_os_ostream adapter:

    #include <llvm/Support/raw_os_ostream.h>
    ...
    raw_os_ostream raw_out(out);
    raw_out << *instruction << std::endl;

It compiles fine, but opt gives a runtime error when trying to load  
the pass:

    Symbol not found: __ZTVN4llvm14raw_os_ostreamE

Any thoughts on why this is happening? And is there a workaround that  
doesn't involve raw_os_ostream? Thanks,

Trevor

On Apr 1, 2010, at 3:52 PM, Trevor Harmon wrote:
> Hi,
> 
> I'm writing some code that prints to std::ostream. However, it seems  
> that all of the LLVM objects can only print to llvm::raw_ostream, so I  
> can't do this:
> 
> void write(std::ostream &out) {
>    ...
>    for (BasicBlock::iterator i = block->begin(), e = block->end(); i
!
> = e; ++i) {
>       Instruction *instruction = i;
>       out << *instruction << std::endl;
>       ...
>    }
>    ...
> }
> 
> I tried working around this problem using the raw_os_ostream adapter:
> 
>    #include <llvm/Support/raw_os_ostream.h>
>    ...
>    raw_os_ostream raw_out(out);
>    raw_out << *instruction << std::endl;
> 
> It compiles fine, but opt gives a runtime error when trying to load  
> the pass:
> 
>    Symbol not found: __ZTVN4llvm14raw_os_ostreamE
> 
> Any thoughts on why this is happening? And is there a workaround that  
> doesn't involve raw_os_ostream? Thanks,
It's hard to say: __ZTVN4llvm14raw_os_ostreamE is the vtable for
raw_os_ostream.  This should be provided by lib/Support/raw_os_ostream.cpp. 
Perhaps you're not linking in that .o file for some reason.  A workaround
would be to use raw_ostream in your code instead of ostream :)

-Chris

On Apr 1, 2010, at 3:58 PM, Chris Lattner wrote:
> It's hard to say: __ZTVN4llvm14raw_os_ostreamE is the vtable for  
> raw_os_ostream.  This should be provided by lib/Support/ 
> raw_os_ostream.cpp.  Perhaps you're not linking in that .o file for  
> some reason.
raw_os_ostream is definitely linked into Debug/lib/libLLVMSupport.a in  
my LLVM build. (Confirmed with otool.) I'm using the 2.7 release  
branch from a couple weeks ago.

Just for kicks, I added some code to my pass that creates a  
circular_raw_ostream object, and it runs without errors. I wonder  
what's different about raw_os_ostream... Any other possibilities?

Trevor