Users always want to run all the checks. The spv_validate_options_t
mechanism, which provides little benefits to users, complicates the
internal implementation and also makes the tests exercise different
paths as users do.
Right now the tests are more like integration tests instead of
unit tests, which should be our next refactoring aim.
This adds function and block layout checks to the validator. Very
basic CFG code has been added to make sure labels and branches
are correctly ordered.
Also:
* MemoryModel and Variable instruction checks/tests
* Use spvCheckReturn instead of CHECK_RESULT
* Fix invalid SSA tests
* Created libspirv::spvResultToString in diagnostic.h
* Documented various functions and classes
* Fixed error messages
* Fixed using declaration for FunctionDecl enum class
* Validates module level instructions for logical layout
conformance
* Does not validate:
1. Function logical layout
2. Minor cases with OpVariable
3. Missing MemoryModel instruction in module
4. Order of function definition and function declaration
* 782 unit tests for logical layout
Addressed feedback
