Mark .rmeta files as /SAFESEH on x86 Windows.

[zetafunction]

Chrome links .rlibs with /WHOLEARCHIVE or -Wl,--whole-archive to prevent the linker from discarding static initializers. This works well, except on Windows x86, where lld complains:

error: /safeseh: lib.rmeta is not compatible with SEH

The fix is simply to mark the .rmeta as SAFESEH aware. This is trivially true, since the metadata file does not contain any executable code.

[rustbot]

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[zetafunction]

Is there a good place to put a helper function for managing the @feat.00 symbol? Right now, this is copied from

rust/compiler/rustc_codegen_ssa/src/back/link.rs

Line 1901 in b2d2184

// Add feature flags to the object file. On MSVC this is optional but LLD will complain if

which I discovered in the course of fixing this bug. @nbdd0121 @petrochenkov

[bjorn3]

You can probably put it in create_object_file and then remove this code from link.rs.

[zetafunction]

You can probably put it in create_object_file and then remove this code from link.rs.

Thanks, that's a good suggestion. I moved it to create_object_file(); however, I made it so create_object_file() always returns an object with mangling enabled.

link.rs separately (re-)disables mangling.

I think having create_object_file() silently return an Object with mangling disabled only for COFF objects is too action-at-a-distance.

[bjorn3]

Thanks, that's a good suggestion. I moved it to create_object_file(); however, I made it so create_object_file() always returns an object with mangling enabled.

link.rs separately (re-)disables mangling.

I think having create_object_file() silently return an Object with mangling disabled only for COFF objects is too action-at-a-distance.

Makes sense.

LGTM with the above nit fixed.

[bjorn3]

@bors r+

[bors]

📌 Commit 8fa800d has been approved by bjorn3

It is now in the queue for this repository.

[bors]

⌛ Testing commit 8fa800d with merge ccb160d...

[bors]

☀️ Test successful - checks-actions
Approved by: bjorn3
Pushing ccb160d to master...

[rust-timer]

Finished benchmarking commit (ccb160d): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.2%	[0.2%, 0.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

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%	[1.7%, 1.7%]	1
Regressions ❌ (secondary)	1.3%	[1.3%, 1.3%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.7%	[1.7%, 1.7%]	1

Cycles

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

Binary size

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

Bootstrap: missing data
Artifact size: 304.46 MiB -> 304.45 MiB (-0.00%)