feat: towards support for globals

[regehr]

this PR registers mlir__global and mlir__addressof, and then follows through with other code supporting this such as verifier support

the short-term goal (not nearly achieved yet) is to run Test/LLVM/global_load_store.mlir though the veir interpreter. this test simple loads from an i32 global, increments the value, and uses the result to store back to the global and also returns it from main().

[github-actions]

VeIR Benchmarks

Details

Benchmark suite	Current: 171e279	Previous: e995cda	Ratio
add-fold-worklist/create	1900000 ns (± 110274)	2266000 ns (± 118215)	0.84
add-fold-worklist/rewrite	3832500 ns (± 59435)	4192500 ns (± 63611)	0.91
add-fold-worklist-local/create	1925000 ns (± 48680)	2301000 ns (± 113070)	0.84
add-fold-worklist-local/rewrite	4671000 ns (± 70163)	5204000 ns (± 184667)	0.90
add-zero-worklist/create	2028500 ns (± 91143)	2257000 ns (± 98643)	0.90
add-zero-worklist/rewrite	2753500 ns (± 41289)	3009000 ns (± 28429)	0.92
add-zero-reuse-worklist/create	1581000 ns (± 23249)	1914000 ns (± 75035)	0.83
add-zero-reuse-worklist/rewrite	2386000 ns (± 25851)	2678000 ns (± 93937)	0.89
mul-two-worklist/create	1918000 ns (± 99760)	2234500 ns (± 112485)	0.86
mul-two-worklist/rewrite	5368500 ns (± 156944)	5918000 ns (± 161062)	0.91
add-fold-forwards/create	1922000 ns (± 86875)	2290000 ns (± 72400)	0.84
add-fold-forwards/rewrite	2713000 ns (± 32334)	3012000 ns (± 11606)	0.90
add-zero-forwards/create	1898000 ns (± 80315)	2343000 ns (± 112877)	0.81
add-zero-forwards/rewrite	1732000 ns (± 25446)	2007000 ns (± 68057)	0.86
add-zero-reuse-forwards/create	1554000 ns (± 17326)	1893000 ns (± 85786)	0.82
add-zero-reuse-forwards/rewrite	1390000 ns (± 16053)	1563000 ns (± 34470)	0.89
mul-two-forwards/create	1902000 ns (± 97085)	2233000 ns (± 94401)	0.85
mul-two-forwards/rewrite	3333000 ns (± 103331)	3673000 ns (± 187633)	0.91
add-zero-reuse-first/create	1582000 ns (± 54048)	1888000 ns (± 56993)	0.84
add-zero-reuse-first/rewrite	9000 ns (± 0)	8000 ns (± 0)	1.13
add-zero-lots-of-reuse-first/create	1581500 ns (± 68888)	2002000 ns (± 58122)	0.79
add-zero-lots-of-reuse-first/rewrite	770000 ns (± 38335)	830000 ns (± 25205)	0.93

This comment was automatically generated by workflow using github-action-benchmark.

[math-fehr]

Nice! I think I only have one two comments that should be addressed, the rest is comments where we should probably create an issue about it and fix it later.

[regehr]

@math-fehr comments addressed and code improved, ready for another quick look, thanks!