Re: Debugging "missing callgraph edge for call stmt"

[Iain Buclaw]

On 1 January 2013 19:22, Johannes Pfau <nos...@example.com> wrote:

> This is a bug which only seems to happen with gdc-4.7. At least I can't
> reproduce it with gcc 4.8 but I'd like to fix it in 4.7 as well if
> possible. (It prevents some phobos modules from being built in unittest
> mode).
>
> First, here's the reduced test case:
> ----------------
> void main()
> {
>     topNIndex();
> }
>
> void topNIndex()() //<= only fails if this is a template
> {
>     bool indirectLess(int a, int b) //<= adding 'static' makes it work
>     {
>         return a > b;
>     }
>     auto a = BinaryHeap!(indirectLess)();
> }
>
> struct BinaryHeap(alias less )
> {
>     void percolateDown()
>     {
>         less(0, 1);
>     }
> }
> ----------------
>
> It's somehow related to closures in templated functions. Making
> topNIndex a function or making indirectLess static fixes the issue.
>
> This is the compiler error:
> ----------------
> bug/std/algorithm2.d:1: error: missing callgraph edge for call stmt:
> algorithm2.topNIndex!().topNIndex.indirectLess (0B, 0, 1);
>
>
> algorithm2.topNIndex!().topNIndex.BinaryHeap!(indirectLess).BinaryHeap.percolateDown/3
> @0x7fe2ce7a6b40 (asm:
>
> _D10algorithm214__T9topNIndexZ9topNIndexFZv82__T10BinaryHeapS63_D10algorithm214__T9topNIndexZ9topNIndexFZv12indirectLessMFiiZbZ10BinaryHeap13percolateDownMFZv)
> analyzed needed reachable body finalized called by: calls:
> _d_assert_msg/5 (1.00 per call) References: Refering this function:
> bug/std/algorithm2.d:1: internal compiler error: verify_cgraph_node
> failed
> ----------------
>
> Any clue what to do about this?
> * Was it probably a gdc specific issue fixed in master but missed when
>   backporting?
> * Could be an issue fixed in the GCC backend, but I can't find a
>   matching bug report?
> * Any clue how to debug this further?
>


Only two suggestions I can give are:

a) Make sure that indirectLess DECL_CONTEXT is topNIndex, and not main in
code generation (eg: you don't want it to look logically like this)

void main()
{
    bool indirectLess(int a, int b)
    {
        return a > b;
    }
    topNIndex();
}

void topNIndex()
{
    auto a = BinaryHeap!(indirectLess);
}


b) Make sure that indirectLess is codegen'd and pushed before topNIndex.


Regards,
-- 
Iain Buclaw

*(p < e ? p++ : p) = (c & 0x0f) + '0';