This times each phase of compilation, so you can see where time is being
spent. This doesn't cover all of compilation, but does get all the major
work being done.
Note that these times are non-overlapping, and should stay that way.
If we add more timers, they should go in a different timer group, so we
don't end up double-counting.
Based on a patch by @cwillmor---thanks, Chris!
Example output, from an -Onone build using a debug compiler:
===-------------------------------------------------------------------------===
Swift compilation
===-------------------------------------------------------------------------===
Total Execution Time: 8.7215 seconds (8.7779 wall clock)
---User Time--- --System Time-- --User+System-- ---Wall Time--- --- Name ---
2.6670 ( 30.8%) 0.0180 ( 25.3%) 2.6850 ( 30.8%) 2.7064 ( 30.8%) Type checking / Semantic analysis
1.9381 ( 22.4%) 0.0034 ( 4.8%) 1.9415 ( 22.3%) 1.9422 ( 22.1%) AST verification
1.0746 ( 12.4%) 0.0089 ( 12.5%) 1.0834 ( 12.4%) 1.0837 ( 12.3%) SILGen
0.8468 ( 9.8%) 0.0171 ( 24.0%) 0.8638 ( 9.9%) 0.8885 ( 10.1%) IRGen
0.6595 ( 7.6%) 0.0142 ( 20.0%) 0.6737 ( 7.7%) 0.6739 ( 7.7%) LLVM output
0.6449 ( 7.5%) 0.0019 ( 2.6%) 0.6468 ( 7.4%) 0.6469 ( 7.4%) SIL verification (pre-optimization)
0.3505 ( 4.1%) 0.0023 ( 3.2%) 0.3528 ( 4.0%) 0.3530 ( 4.0%) SIL optimization
0.2632 ( 3.0%) 0.0005 ( 0.7%) 0.2637 ( 3.0%) 0.2639 ( 3.0%) SIL verification (post-optimization)
0.0718 ( 0.8%) 0.0021 ( 3.0%) 0.0739 ( 0.8%) 0.0804 ( 0.9%) Parsing
0.0618 ( 0.7%) 0.0010 ( 1.4%) 0.0628 ( 0.7%) 0.0628 ( 0.7%) LLVM optimization
0.0484 ( 0.6%) 0.0011 ( 1.5%) 0.0495 ( 0.6%) 0.0495 ( 0.6%) Serialization (swiftmodule)
0.0240 ( 0.3%) 0.0006 ( 0.9%) 0.0246 ( 0.3%) 0.0267 ( 0.3%) Serialization (swiftdoc)
0.0000 ( 0.0%) 0.0000 ( 0.0%) 0.0000 ( 0.0%) 0.0000 ( 0.0%) Name binding
8.6505 (100.0%) 0.0710 (100.0%) 8.7215 (100.0%) 8.7779 (100.0%) Total
