Nul terminate rust string literals

[bjorn3]

This allows taking advantage of the C string merging functionality of linkers, reducing code size.

Marked as draft to see if this actually has much of an effect. The disadvantage of this is that people may start to rely on string literals getting nul terminated. A potential solution for that would be to put a byte that is not part of a valid UTF-8 character right before the nul terminator.

Builds on #138503

[rustbot]

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[bjorn3]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 7c1cd9b with merge f949c9f...

[bors]

☀️ Try build successful - checks-actions
Build commit: f949c9f (f949c9f96faec0a24e98f55e36cfa88c14c2199c)

[rust-timer]

Finished benchmarking commit (f949c9f): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.2%	[0.3%, 1.8%]	5
Improvements ✅ (primary)	-1.2%	[-4.3%, -0.3%]	12
Improvements ✅ (secondary)	-1.5%	[-6.6%, -0.4%]	21
All ❌✅ (primary)	-1.2%	[-4.3%, -0.3%]	12

Max RSS (memory usage)

Results (primary 1.6%, secondary 2.0%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	2.2%	[1.1%, 4.4%]	4
Regressions ❌ (secondary)	3.7%	[1.9%, 4.8%]	3
Improvements ✅ (primary)	-1.2%	[-1.2%, -1.2%]	1
Improvements ✅ (secondary)	-3.3%	[-3.3%, -3.3%]	1
All ❌✅ (primary)	1.6%	[-1.2%, 4.4%]	5

Cycles

Results (primary -2.3%, secondary -3.2%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.4%	[2.3%, 2.6%]	2
Improvements ✅ (primary)	-2.3%	[-3.8%, -1.2%]	3
Improvements ✅ (secondary)	-5.5%	[-6.4%, -4.1%]	5
All ❌✅ (primary)	-2.3%	[-3.8%, -1.2%]	3

Binary size

Results (primary -0.5%, secondary -0.3%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.0%, 0.1%]	8
Regressions ❌ (secondary)	0.0%	[0.0%, 0.0%]	32
Improvements ✅ (primary)	-0.6%	[-2.5%, -0.0%]	100
Improvements ✅ (secondary)	-0.5%	[-3.0%, -0.0%]	43
All ❌✅ (primary)	-0.5%	[-2.5%, 0.1%]	108

Bootstrap: 775.364s -> 772.882s (-0.32%)
Artifact size: 365.01 MiB -> 365.44 MiB (0.12%)