rustc: Implement #[link(cfg(..))] and crt-static #37545

alexcrichton · 2016-11-03T00:42:39Z

This commit is an implementation of RFC 1721 which adds a new target feature
to the compiler, crt-static, which can be used to select how the C runtime for
a target is linked. Most targets dynamically linke the C runtime by default with
the notable exception of some of the musl targets.

This commit first adds the new target-feature, crt-static. If enabled, then
the cfg(target_feature = "crt-static") will be available. Targets like musl
will have this enabled by default. This feature can be controlled through the
standard target-feature interface, -C target-feature=+crt-static or
-C target-feature=-crt-static.

Next this adds an gated and unstable #[link(cfg(..))] feature to enable the
crt-static semantics we want with libc. The exact behavior of this attribute
is a little squishy, but it's intended to be a forever-unstable
implementation detail of the liblibc crate.

Specifically the #[link(cfg(..))] annotation means that the #[link]
directive is only active in a compilation unit if that cfg value is satisfied.
For example when compiling an rlib, these directives are just encoded and
ignored for dylibs, and all staticlibs are continued to be put into the rlib as
usual. When placing that rlib into a staticlib, executable, or dylib, however,
the cfg is evaluated as if it were defined in the final artifact and the
library is decided to be linked or not.

Essentially, what'll happen is:

On MSVC with -C target-feature=-crt-static, the msvcrt.lib library will be
linked to.
On MSVC with -C target-feature=+crt-static, the libcmt.lib library will be
linked to.
On musl with -C target-feature=-crt-static, the object files in liblibc.rlib
are removed and -lc is passed instead.
On musl with -C target-feature=+crt-static, the object files in liblibc.rlib
are used and -lc is not passed.

This commit does not include an update to the liblibc module to implement
these changes. I plan to do that just after the 1.14.0 beta release is cut to
ensure we get ample time to test this feature.

cc #37406

rust-highfive · 2016-11-03T00:42:44Z

r? @eddyb

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

alexcrichton · 2016-11-03T00:46:18Z

r? @brson

alexcrichton · 2016-11-03T00:47:39Z

I tested bootstrapping this with this commit: alexcrichton/libc@5699631. With that I was able to produce static/dynamic MSVC and musl binaries with the flip of this switch, so it's at least confirmed to work there!

retep998 · 2016-11-03T04:18:41Z

If possible, it would be really nice to have options for the debug versions of the CRT, msvcrtd.lib and libcmtd.lib.

bors · 2016-11-06T09:58:27Z

☔ The latest upstream changes (presumably #37597) made this pull request unmergeable. Please resolve the merge conflicts.

bors · 2016-11-09T23:19:23Z

☔ The latest upstream changes (presumably #37670) made this pull request unmergeable. Please resolve the merge conflicts.

In preparation for rust-lang/rust#37545 this is adding the appropriate directives to libc to get included.

Use `#[link(cfg(..))]` in preparation for libstd In preparation for rust-lang/rust#37545 this is adding the appropriate directives to libc to get included.

alexcrichton · 2016-11-10T03:33:24Z

Ok, I've updated this and now that beta has been released I went ahead and included the update to liblibc.

bors · 2016-11-10T13:13:38Z

☔ The latest upstream changes (presumably #37463) made this pull request unmergeable. Please resolve the merge conflicts.

bors · 2016-11-10T16:21:15Z

☔ The latest upstream changes (presumably #37542) made this pull request unmergeable. Please resolve the merge conflicts.

brson · 2016-11-10T23:56:02Z

@bors r+

bors · 2016-11-10T23:56:03Z

📌 Commit aede832 has been approved by brson

brson · 2016-11-11T00:01:19Z

@bors r-

Seems like we should feature-gate the crt-static target feature so it can't be mentioned on the command line yet.

alexcrichton · 2016-11-11T17:07:24Z

@bors: r=brson

Hooked up -C target-feature=+crt-static to -Z unstable-options

bors · 2016-11-11T17:07:25Z

📌 Commit 791763b has been approved by brson

rustc: Implement #[link(cfg(..))] and crt-static This commit is an implementation of [RFC 1721] which adds a new target feature to the compiler, `crt-static`, which can be used to select how the C runtime for a target is linked. Most targets dynamically linke the C runtime by default with the notable exception of some of the musl targets. [RFC 1721]: https://github.com/rust-lang/rfcs/blob/master/text/1721-crt-static.md This commit first adds the new target-feature, `crt-static`. If enabled, then the `cfg(target_feature = "crt-static")` will be available. Targets like musl will have this enabled by default. This feature can be controlled through the standard target-feature interface, `-C target-feature=+crt-static` or `-C target-feature=-crt-static`. Next this adds an gated and unstable `#[link(cfg(..))]` feature to enable the `crt-static` semantics we want with libc. The exact behavior of this attribute is a little squishy, but it's intended to be a forever-unstable implementation detail of the liblibc crate. Specifically the `#[link(cfg(..))]` annotation means that the `#[link]` directive is only active in a compilation unit if that `cfg` value is satisfied. For example when compiling an rlib, these directives are just encoded and ignored for dylibs, and all staticlibs are continued to be put into the rlib as usual. When placing that rlib into a staticlib, executable, or dylib, however, the `cfg` is evaluated *as if it were defined in the final artifact* and the library is decided to be linked or not. Essentially, what'll happen is: * On MSVC with `-C target-feature=-crt-static`, the `msvcrt.lib` library will be linked to. * On MSVC with `-C target-feature=+crt-static`, the `libcmt.lib` library will be linked to. * On musl with `-C target-feature=-crt-static`, the object files in liblibc.rlib are removed and `-lc` is passed instead. * On musl with `-C target-feature=+crt-static`, the object files in liblibc.rlib are used and `-lc` is not passed. This commit does **not** include an update to the liblibc module to implement these changes. I plan to do that just after the 1.14.0 beta release is cut to ensure we get ample time to test this feature. cc rust-lang#37406

bors · 2016-11-15T15:21:29Z

📌 Commit 957d3e9 has been approved by brson

bors · 2016-11-15T15:58:12Z

⌛ Testing commit 957d3e9 with merge a4add40...

rustc: Implement #[link(cfg(..))] and crt-static This commit is an implementation of [RFC 1721] which adds a new target feature to the compiler, `crt-static`, which can be used to select how the C runtime for a target is linked. Most targets dynamically linke the C runtime by default with the notable exception of some of the musl targets. [RFC 1721]: https://github.com/rust-lang/rfcs/blob/master/text/1721-crt-static.md This commit first adds the new target-feature, `crt-static`. If enabled, then the `cfg(target_feature = "crt-static")` will be available. Targets like musl will have this enabled by default. This feature can be controlled through the standard target-feature interface, `-C target-feature=+crt-static` or `-C target-feature=-crt-static`. Next this adds an gated and unstable `#[link(cfg(..))]` feature to enable the `crt-static` semantics we want with libc. The exact behavior of this attribute is a little squishy, but it's intended to be a forever-unstable implementation detail of the liblibc crate. Specifically the `#[link(cfg(..))]` annotation means that the `#[link]` directive is only active in a compilation unit if that `cfg` value is satisfied. For example when compiling an rlib, these directives are just encoded and ignored for dylibs, and all staticlibs are continued to be put into the rlib as usual. When placing that rlib into a staticlib, executable, or dylib, however, the `cfg` is evaluated *as if it were defined in the final artifact* and the library is decided to be linked or not. Essentially, what'll happen is: * On MSVC with `-C target-feature=-crt-static`, the `msvcrt.lib` library will be linked to. * On MSVC with `-C target-feature=+crt-static`, the `libcmt.lib` library will be linked to. * On musl with `-C target-feature=-crt-static`, the object files in liblibc.rlib are removed and `-lc` is passed instead. * On musl with `-C target-feature=+crt-static`, the object files in liblibc.rlib are used and `-lc` is not passed. This commit does **not** include an update to the liblibc module to implement these changes. I plan to do that just after the 1.14.0 beta release is cut to ensure we get ample time to test this feature. cc #37406

bors · 2016-11-15T17:10:20Z

💔 Test failed - auto-win-gnu-32-opt-rustbuild

alexcrichton · 2016-11-15T17:47:20Z

@bors: r=brson

bors · 2016-11-15T17:47:21Z

📌 Commit 9a9189c has been approved by brson

bors · 2016-11-15T20:15:47Z

⌛ Testing commit 9a9189c with merge fdb5fa1...

bors · 2016-11-15T21:19:29Z

💔 Test failed - auto-win-gnu-32-opt-rustbuild

This commit is an implementation of [RFC 1721] which adds a new target feature to the compiler, `crt-static`, which can be used to select how the C runtime for a target is linked. Most targets dynamically linke the C runtime by default with the notable exception of some of the musl targets. [RFC 1721]: https://github.com/rust-lang/rfcs/blob/master/text/1721-crt-static.md This commit first adds the new target-feature, `crt-static`. If enabled, then the `cfg(target_feature = "crt-static")` will be available. Targets like musl will have this enabled by default. This feature can be controlled through the standard target-feature interface, `-C target-feature=+crt-static` or `-C target-feature=-crt-static`. Next this adds an gated and unstable `#[link(cfg(..))]` feature to enable the `crt-static` semantics we want with libc. The exact behavior of this attribute is a little squishy, but it's intended to be a forever-unstable implementation detail of the liblibc crate. Specifically the `#[link(cfg(..))]` annotation means that the `#[link]` directive is only active in a compilation unit if that `cfg` value is satisfied. For example when compiling an rlib, these directives are just encoded and ignored for dylibs, and all staticlibs are continued to be put into the rlib as usual. When placing that rlib into a staticlib, executable, or dylib, however, the `cfg` is evaluated *as if it were defined in the final artifact* and the library is decided to be linked or not. Essentially, what'll happen is: * On MSVC with `-C target-feature=-crt-static`, the `msvcrt.lib` library will be linked to. * On MSVC with `-C target-feature=+crt-static`, the `libcmt.lib` library will be linked to. * On musl with `-C target-feature=-crt-static`, the object files in liblibc.rlib are removed and `-lc` is passed instead. * On musl with `-C target-feature=+crt-static`, the object files in liblibc.rlib are used and `-lc` is not passed. This commit does **not** include an update to the liblibc module to implement these changes. I plan to do that just after the 1.14.0 beta release is cut to ensure we get ample time to test this feature. cc rust-lang#37406

alexcrichton · 2016-11-16T15:01:51Z

@bors: r=brson

bors · 2016-11-16T15:01:55Z

📌 Commit 06242ff has been approved by brson

bors · 2016-11-16T16:25:39Z

⌛ Testing commit 06242ff with merge 9d4b6fa...

rustc: Implement #[link(cfg(..))] and crt-static This commit is an implementation of [RFC 1721] which adds a new target feature to the compiler, `crt-static`, which can be used to select how the C runtime for a target is linked. Most targets dynamically linke the C runtime by default with the notable exception of some of the musl targets. [RFC 1721]: https://github.com/rust-lang/rfcs/blob/master/text/1721-crt-static.md This commit first adds the new target-feature, `crt-static`. If enabled, then the `cfg(target_feature = "crt-static")` will be available. Targets like musl will have this enabled by default. This feature can be controlled through the standard target-feature interface, `-C target-feature=+crt-static` or `-C target-feature=-crt-static`. Next this adds an gated and unstable `#[link(cfg(..))]` feature to enable the `crt-static` semantics we want with libc. The exact behavior of this attribute is a little squishy, but it's intended to be a forever-unstable implementation detail of the liblibc crate. Specifically the `#[link(cfg(..))]` annotation means that the `#[link]` directive is only active in a compilation unit if that `cfg` value is satisfied. For example when compiling an rlib, these directives are just encoded and ignored for dylibs, and all staticlibs are continued to be put into the rlib as usual. When placing that rlib into a staticlib, executable, or dylib, however, the `cfg` is evaluated *as if it were defined in the final artifact* and the library is decided to be linked or not. Essentially, what'll happen is: * On MSVC with `-C target-feature=-crt-static`, the `msvcrt.lib` library will be linked to. * On MSVC with `-C target-feature=+crt-static`, the `libcmt.lib` library will be linked to. * On musl with `-C target-feature=-crt-static`, the object files in liblibc.rlib are removed and `-lc` is passed instead. * On musl with `-C target-feature=+crt-static`, the object files in liblibc.rlib are used and `-lc` is not passed. This commit does **not** include an update to the liblibc module to implement these changes. I plan to do that just after the 1.14.0 beta release is cut to ensure we get ample time to test this feature. cc #37406

bors · 2016-11-16T19:47:16Z

This dependency requirement should go away once rust-lang/rust#37545 is implemented. I'm creating version 0.2.9.1, which points to upstream 0.2.9 as a package only version to get this dependency in.

-gnu is somewhat broken using cdylib: rust-lang/rust#37530 But we should be able to statically link msvcrt: rust-lang/rust#37545

rust-highfive assigned eddyb Nov 3, 2016

rust-highfive assigned brson and unassigned eddyb Nov 3, 2016

japaric mentioned this pull request Nov 4, 2016

How to compile rust in a musl libc based linux system #31322

Closed

alexcrichton force-pushed the crt-static branch from 4487091 to 6da63c8 Compare November 6, 2016 16:33

alexcrichton added a commit to alexcrichton/libc that referenced this pull request Nov 10, 2016

Use #[link(cfg(..))] in preparation for libstd

f9323d1

In preparation for rust-lang/rust#37545 this is adding the appropriate directives to libc to get included.

alexcrichton mentioned this pull request Nov 10, 2016

Use #[link(cfg(..))] in preparation for libstd rust-lang/libc#446

Merged

alexcrichton force-pushed the crt-static branch from 6da63c8 to f5c9fb6 Compare November 10, 2016 03:32

alexcrichton force-pushed the crt-static branch from f5c9fb6 to 0d329a2 Compare November 10, 2016 16:08

alexcrichton force-pushed the crt-static branch 2 times, most recently from 51af985 to aede832 Compare November 10, 2016 19:52

alexcrichton added the T-tools label Nov 10, 2016

alexcrichton force-pushed the crt-static branch 2 times, most recently from 21d77be to 791763b Compare November 11, 2016 17:06

alexcrichton force-pushed the crt-static branch from 957d3e9 to 9a9189c Compare November 15, 2016 17:46

alexcrichton force-pushed the crt-static branch from 9a9189c to 06242ff Compare November 16, 2016 15:00

This was referenced Nov 16, 2016

Do not link statically against libc by default for musl targets rust-lang/libc#314

Closed

Can't statically link MSVC runtime rust-lang/libc#290

Closed

bors merged commit 06242ff into rust-lang:master Nov 16, 2016

This was referenced Nov 16, 2016

add --crate-type metadata #37681

Merged

Support useing externally defined macros behind #![feature(use_extern_macros)] #37732

Merged

Implement the loop_break_value feature. #37487

Merged

retep998 mentioned this pull request Nov 18, 2016

add to package repositories BurntSushi/ripgrep#10

Closed

urschrei added a commit to urschrei/lonlat_bng that referenced this pull request Nov 20, 2016

Switch back to dylib

6c640e6

-gnu is somewhat broken using cdylib: rust-lang/rust#37530 But we should be able to statically link msvcrt: rust-lang/rust#37545

retep998 mentioned this pull request Dec 14, 2016

Don't get memcpy, memmove, memcmp, memset, and strlen from msvcrt.dll #29130

Closed

alexcrichton deleted the crt-static branch December 19, 2016 20:45

jdm mentioned this pull request Jan 23, 2017

rustc always links against non-debug Windows runtime #39016

Open

petrochenkov mentioned this pull request May 10, 2020

rustc-book: Document -C target-feature=+crt-static #71586

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rustc: Implement #[link(cfg(..))] and crt-static #37545

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rustc: Implement #[link(cfg(..))] and crt-static #37545

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