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Auto merge of #12535 - hi-rustin:rustin-patch-linker, r=weihanglo
Add support for `target.'cfg(..)'.linker`
2 parents b8df7aa + c9cc3b9 commit bfa04bb

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10 files changed

+189
-19
lines changed

10 files changed

+189
-19
lines changed

‎src/cargo/core/compiler/build_context/mod.rs

-10
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,6 @@ use crate::util::errors::CargoResult;
1010
use crate::util::interning::InternedString;
1111
use crate::util::Rustc;
1212
use std::collections::{HashMap, HashSet};
13-
use std::path::PathBuf;
1413

1514
mod target_info;
1615
pub use self::target_info::{
@@ -120,15 +119,6 @@ impl<'a, 'cfg> BuildContext<'a, 'cfg> {
120119
&self.target_data.rustc
121120
}
122121

123-
/// Gets the user-specified linker for a particular host or target.
124-
pub fn linker(&self, kind: CompileKind) -> Option<PathBuf> {
125-
self.target_data
126-
.target_config(kind)
127-
.linker
128-
.as_ref()
129-
.map(|l| l.val.clone().resolve_program(self.config))
130-
}
131-
132122
/// Gets the host architecture triple.
133123
///
134124
/// For example, x86_64-unknown-linux-gnu, would be

‎src/cargo/core/compiler/compilation.rs

+50
Original file line numberDiff line numberDiff line change
@@ -104,6 +104,8 @@ pub struct Compilation<'cfg> {
104104
primary_rustc_process: Option<ProcessBuilder>,
105105

106106
target_runners: HashMap<CompileKind, Option<(PathBuf, Vec<String>)>>,
107+
/// The linker to use for each host or target.
108+
target_linkers: HashMap<CompileKind, Option<PathBuf>>,
107109
}
108110

109111
impl<'cfg> Compilation<'cfg> {
@@ -150,6 +152,13 @@ impl<'cfg> Compilation<'cfg> {
150152
.chain(Some(&CompileKind::Host))
151153
.map(|kind| Ok((*kind, target_runner(bcx, *kind)?)))
152154
.collect::<CargoResult<HashMap<_, _>>>()?,
155+
target_linkers: bcx
156+
.build_config
157+
.requested_kinds
158+
.iter()
159+
.chain(Some(&CompileKind::Host))
160+
.map(|kind| Ok((*kind, target_linker(bcx, *kind)?)))
161+
.collect::<CargoResult<HashMap<_, _>>>()?,
153162
})
154163
}
155164

@@ -221,6 +230,11 @@ impl<'cfg> Compilation<'cfg> {
221230
self.target_runners.get(&kind).and_then(|x| x.as_ref())
222231
}
223232

233+
/// Gets the user-specified linker for a particular host or target.
234+
pub fn target_linker(&self, kind: CompileKind) -> Option<PathBuf> {
235+
self.target_linkers.get(&kind).and_then(|x| x.clone())
236+
}
237+
224238
/// Returns a [`ProcessBuilder`] appropriate for running a process for the
225239
/// target platform. This is typically used for `cargo run` and `cargo
226240
/// test`.
@@ -442,3 +456,39 @@ fn target_runner(
442456
)
443457
}))
444458
}
459+
460+
/// Gets the user-specified linker for a particular host or target from the configuration.
461+
fn target_linker(bcx: &BuildContext<'_, '_>, kind: CompileKind) -> CargoResult<Option<PathBuf>> {
462+
// Try host.linker and target.{}.linker.
463+
if let Some(path) = bcx
464+
.target_data
465+
.target_config(kind)
466+
.linker
467+
.as_ref()
468+
.map(|l| l.val.clone().resolve_program(bcx.config))
469+
{
470+
return Ok(Some(path));
471+
}
472+
473+
// Try target.'cfg(...)'.linker.
474+
let target_cfg = bcx.target_data.info(kind).cfg();
475+
let mut cfgs = bcx
476+
.config
477+
.target_cfgs()?
478+
.iter()
479+
.filter_map(|(key, cfg)| cfg.linker.as_ref().map(|linker| (key, linker)))
480+
.filter(|(key, _linker)| CfgExpr::matches_key(key, target_cfg));
481+
let matching_linker = cfgs.next();
482+
if let Some((key, linker)) = cfgs.next() {
483+
anyhow::bail!(
484+
"several matching instances of `target.'cfg(..)'.linker` in configurations\n\
485+
first match `{}` located in {}\n\
486+
second match `{}` located in {}",
487+
matching_linker.unwrap().0,
488+
matching_linker.unwrap().1.definition,
489+
key,
490+
linker.definition
491+
);
492+
}
493+
Ok(matching_linker.map(|(_k, linker)| linker.val.clone().resolve_program(bcx.config)))
494+
}

‎src/cargo/core/compiler/context/mod.rs

+1-1
Original file line numberDiff line numberDiff line change
@@ -272,7 +272,7 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
272272
unit: unit.clone(),
273273
args,
274274
unstable_opts,
275-
linker: self.bcx.linker(unit.kind),
275+
linker: self.compilation.target_linker(unit.kind).clone(),
276276
script_meta,
277277
env: artifact::get_env(&self, self.unit_deps(unit))?,
278278
});

‎src/cargo/core/compiler/custom_build.rs

+2-5
Original file line numberDiff line numberDiff line change
@@ -299,11 +299,8 @@ fn build_work(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Job> {
299299
cmd.env(&var, value);
300300
}
301301

302-
if let Some(linker) = &bcx.target_data.target_config(unit.kind).linker {
303-
cmd.env(
304-
"RUSTC_LINKER",
305-
linker.val.clone().resolve_program(bcx.config),
306-
);
302+
if let Some(linker) = &cx.compilation.target_linker(unit.kind) {
303+
cmd.env("RUSTC_LINKER", linker);
307304
}
308305

309306
if let Some(links) = unit.pkg.manifest().links() {

‎src/cargo/core/compiler/fingerprint/mod.rs

+1-1
Original file line numberDiff line numberDiff line change
@@ -1426,7 +1426,7 @@ fn calculate_normal(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Finger
14261426
let m = unit.pkg.manifest().metadata();
14271427
let metadata = util::hash_u64((&m.authors, &m.description, &m.homepage, &m.repository));
14281428
let mut config = StableHasher::new();
1429-
if let Some(linker) = cx.bcx.linker(unit.kind) {
1429+
if let Some(linker) = cx.compilation.target_linker(unit.kind) {
14301430
linker.hash(&mut config);
14311431
}
14321432
if unit.mode.is_doc() && cx.bcx.config.cli_unstable().rustdoc_map {

‎src/cargo/core/compiler/mod.rs

+4-1
Original file line numberDiff line numberDiff line change
@@ -1117,7 +1117,10 @@ fn build_base_args(cx: &Context<'_, '_>, cmd: &mut ProcessBuilder, unit: &Unit)
11171117
cmd,
11181118
"-C",
11191119
"linker=",
1120-
bcx.linker(unit.kind).as_ref().map(|s| s.as_ref()),
1120+
cx.compilation
1121+
.target_linker(unit.kind)
1122+
.as_ref()
1123+
.map(|s| s.as_ref()),
11211124
);
11221125
if incremental {
11231126
let dir = cx.files().layout(unit.kind).incremental().as_os_str();

‎src/cargo/util/config/target.rs

+1
Original file line numberDiff line numberDiff line change
@@ -12,6 +12,7 @@ use std::path::PathBuf;
1212
pub struct TargetCfgConfig {
1313
pub runner: OptValue<PathAndArgs>,
1414
pub rustflags: OptValue<StringList>,
15+
pub linker: OptValue<ConfigRelativePath>,
1516
// This is here just to ignore fields from normal `TargetConfig` because
1617
// all `[target]` tables are getting deserialized, whether they start with
1718
// `cfg(` or not.

‎src/doc/src/reference/config.md

+6
Original file line numberDiff line numberDiff line change
@@ -1099,6 +1099,12 @@ This option is deprecated and unused.
10991099
Specifies the linker which is passed to `rustc` (via [`-C linker`]) when the
11001100
[`<triple>`] is being compiled for. By default, the linker is not overridden.
11011101

1102+
##### `target.<cfg>.linker`
1103+
This is similar to the [target linker](#targettriplelinker), but using
1104+
a [`cfg()` expression]. If both a [`<triple>`] and `<cfg>` runner match,
1105+
the `<triple>` will take precedence. It is an error if more than one
1106+
`<cfg>` runner matches the current target.
1107+
11021108
##### `target.<triple>.runner`
11031109
* Type: string or array of strings ([program path with args])
11041110
* Default: none

‎tests/testsuite/build_script.rs

+37
Original file line numberDiff line numberDiff line change
@@ -453,6 +453,43 @@ fn custom_build_env_var_rustc_linker() {
453453
p.cargo("build --target").arg(&target).run();
454454
}
455455

456+
// Only run this test on linux, since it's difficult to construct
457+
// a case suitable for all platforms.
458+
// See:https://github.com/rust-lang/cargo/pull/12535#discussion_r1306618264
459+
#[cargo_test]
460+
#[cfg(target_os = "linux")]
461+
fn custom_build_env_var_rustc_linker_with_target_cfg() {
462+
if cross_compile::disabled() {
463+
return;
464+
}
465+
466+
let target = cross_compile::alternate();
467+
let p = project()
468+
.file(
469+
".cargo/config",
470+
r#"
471+
[target.'cfg(target_pointer_width = "32")']
472+
linker = "/path/to/linker"
473+
"#,
474+
)
475+
.file(
476+
"build.rs",
477+
r#"
478+
use std::env;
479+
480+
fn main() {
481+
assert!(env::var("RUSTC_LINKER").unwrap().ends_with("/path/to/linker"));
482+
}
483+
"#,
484+
)
485+
.file("src/lib.rs", "")
486+
.build();
487+
488+
// no crate type set => linker never called => build succeeds if and
489+
// only if build.rs succeeds, despite linker binary not existing.
490+
p.cargo("build --target").arg(&target).run();
491+
}
492+
456493
#[cargo_test]
457494
fn custom_build_env_var_rustc_linker_bad_host_target() {
458495
let target = rustc_host();

‎tests/testsuite/tool_paths.rs

+87-1
Original file line numberDiff line numberDiff line change
@@ -32,6 +32,93 @@ fn pathless_tools() {
3232
.run();
3333
}
3434

35+
// can set a custom linker via `target.'cfg(..)'.linker`
36+
#[cargo_test]
37+
fn custom_linker_cfg() {
38+
let foo = project()
39+
.file("Cargo.toml", &basic_lib_manifest("foo"))
40+
.file("src/lib.rs", "")
41+
.file(
42+
".cargo/config",
43+
r#"
44+
[target.'cfg(not(target_os = "none"))']
45+
linker = "nonexistent-linker"
46+
"#,
47+
)
48+
.build();
49+
50+
foo.cargo("build --verbose")
51+
.with_stderr(
52+
"\
53+
[COMPILING] foo v0.5.0 ([CWD])
54+
[RUNNING] `rustc [..] -C linker=nonexistent-linker [..]`
55+
[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
56+
",
57+
)
58+
.run();
59+
}
60+
61+
// custom linker set via `target.$triple.linker` have precede over `target.'cfg(..)'.linker`
62+
#[cargo_test]
63+
fn custom_linker_cfg_precedence() {
64+
let target = rustc_host();
65+
66+
let foo = project()
67+
.file("Cargo.toml", &basic_lib_manifest("foo"))
68+
.file("src/lib.rs", "")
69+
.file(
70+
".cargo/config",
71+
&format!(
72+
r#"
73+
[target.'cfg(not(target_os = "none"))']
74+
linker = "ignored-linker"
75+
[target.{}]
76+
linker = "nonexistent-linker"
77+
"#,
78+
target
79+
),
80+
)
81+
.build();
82+
83+
foo.cargo("build --verbose")
84+
.with_stderr(
85+
"\
86+
[COMPILING] foo v0.5.0 ([CWD])
87+
[RUNNING] `rustc [..] -C linker=nonexistent-linker [..]`
88+
[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
89+
",
90+
)
91+
.run();
92+
}
93+
94+
#[cargo_test]
95+
fn custom_linker_cfg_collision() {
96+
let foo = project()
97+
.file("Cargo.toml", &basic_lib_manifest("foo"))
98+
.file("src/lib.rs", "")
99+
.file(
100+
".cargo/config",
101+
r#"
102+
[target.'cfg(not(target_arch = "avr"))']
103+
linker = "nonexistent-linker1"
104+
[target.'cfg(not(target_os = "none"))']
105+
linker = "nonexistent-linker2"
106+
"#,
107+
)
108+
.build();
109+
110+
foo.cargo("build --verbose")
111+
.with_status(101)
112+
.with_stderr(&format!(
113+
"\
114+
[ERROR] several matching instances of `target.'cfg(..)'.linker` in configurations
115+
first match `cfg(not(target_arch = \"avr\"))` located in [..]/foo/.cargo/config
116+
second match `cfg(not(target_os = \"none\"))` located in [..]/foo/.cargo/config
117+
",
118+
))
119+
.run();
120+
}
121+
35122
#[cargo_test]
36123
fn absolute_tools() {
37124
let target = rustc_host();
@@ -393,7 +480,6 @@ fn cfg_ignored_fields() {
393480
[WARNING] unused key `ar` in [target] config table `cfg(not(target_os = \"none\"))`
394481
[WARNING] unused key `foo` in [target] config table `cfg(not(target_os = \"none\"))`
395482
[WARNING] unused key `invalid` in [target] config table `cfg(not(target_os = \"none\"))`
396-
[WARNING] unused key `linker` in [target] config table `cfg(not(target_os = \"none\"))`
397483
[CHECKING] foo v0.0.1 ([..])
398484
[FINISHED] [..]
399485
",

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