Previously we keep a separate static grammar table for opcodes/
operands per SPIR-V version. This commit changes that to use a
single unified static grammar table for opcodes/operands.
This essentially changes how grammar facts are queried against
a certain target environment. There are only limited filtering
according to the desired target environment; a symbol is
considered as available as long as:
1. The target environment satisfies the minimal requirement of
the symbol; or
2. There is at least one extension enabling this symbol.
Note that the second rule assumes the extension enabling the
symbol is indeed requested in the SPIR-V code; checking that
should be the validator's work.
Also fixed a few grammar related issues:
* Rounding mode capability requirements are moved to client APIs.
* Reserved symbols not available in any extension is no longer
recognized by assembler.
Function static non-POD data causes problems with DLL lifetime.
This pull request turns all static info tables into strict POD
tables. Specifically, the capabilities/extensions field of
opcode/operand/extended-instruction table are turned into two
fields, one for the count and the other a pointer to an array of
capabilities/extensions. CapabilitySet/EnumSet are not used in
the static table anymore, but they are still used for checking
inclusion by constructing on the fly, which should be cheap for
the majority cases.
Also moves all these tables into the global namespace to avoid
C++11 function static thread-safe initialization overhead.
