There was a potential problem if variables were invalidated and SPIR-V
read expressions which depended on other expression which in turn depended on the
invalidated variable.
Also fixes issue where variables were considered immutable if they were
forwardable. This allowed some incorrect optimizations to slip through.
OpName is only for debug information, so we must be very careful that
we do not reuse the same name for different variables.
This was previously done for local variables, but this commit extends
this to global variables as well.
Reformats the entire codebase. Better to do it now than later.
Adds .clang-format and a convenience script format_all.sh which formats
everything automatically.
Add virtual CompilerGLSL emit_sampled_image_op function for OpSampledImage.
Under MSL, set sampler ID for local OpSampledImage objects and extract it when emitting sampler.
