Every time an event happens in the library that the user should be
aware of, the callback will be invoked.
The existing diagnostic mechanism is hijacked internally by a
callback that creates an diagnostic object each time an event
happens.
For fulfilling this purpose, the |opcode| field in the
|spv_parsed_instruction_t| struct is changed to of type uint16_t.
Also add functions to query the information of a given SPIR-V
target environment.
This patch uses a Python script to parse the JSON grammar file to
generate the opcode table and operand kind tables.
Now we don't need to do the post-processing (from OperandClass
to spv_operand_type_t) and copying of the opcode info table is
not required anymore!
Previously the opcode table is declared as an global array and we
have spvOpcodeTableInitialize() modifying it. That can result in
race condition. Now spvOpcodeTabelGet() copies the whole underlying
array.
