Shader debug printf doesn't work as expected

[Inori]

As state by the comments:

There may be some bugs for current implementation
(or bugs for validation layer, I'm not sure),
It can not print more than one debug string,
and even worse, the validation layer always complains 
buffer size not enough even I provide 65536 bytes.
And crashes randomly.
I've compared the spir-v code generated by
this function and glslc compiler, and I see
no difference, so I don't know why by now.

[Inori]

Problem solved.
What we need is just a very big printf buffer.

[Inori]

KhronosGroup/Vulkan-ValidationLayers#4074