coverage: Prepare mappings separately from injecting statements

[Zalathar]

These two tasks historically needed to be interleaved, but after various recent changes (including #116046 and #116917) they can now be fully separated.

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@rustbot label +A-code-coverage

[rustbot]

r? @cjgillot

(rustbot has picked a reviewer for you, use r? to override)

[rustbot]

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

[cjgillot]

@bors r+

[bors]

📌 Commit 3f67118 has been approved by cjgillot

It is now in the queue for this repository.

[bors]

⌛ Testing commit 3f67118 with merge e45a937...

[bors]

☀️ Test successful - checks-actions
Approved by: cjgillot
Pushing e45a937 to master...

[rust-timer]

Finished benchmarking commit (e45a937): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

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)	1.7%	[1.1%, 2.4%]	2
Regressions ❌ (secondary)	3.2%	[3.2%, 3.2%]	1
Improvements ✅ (primary)	-2.9%	[-2.9%, -2.9%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[-2.9%, 2.4%]	3

Cycles

Results

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)	-	-	0
Improvements ✅ (primary)	-0.5%	[-0.5%, -0.5%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.5%	[-0.5%, -0.5%]	1

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 668.324s -> 669.011s (0.10%)
Artifact size: 311.76 MiB -> 311.79 MiB (0.01%)