Reduce the build time of the tests (#3304)

When building the tests we also build extra stuff that we don't need,
for example the linux-api C bindings. This PR reduces the build time of
the tests from 66 seconds to 42 seconds (207 compilation units to 150)
when built with `./setup build --test`, as documented in the report from
`cargo build --timings`. The next most problematic crates are the
linux-api, vasi-sync, formatting-nostd/toml-edit, and neli crates due to
their use of syn and related proc macros, but there's not much we can do
about those.

src/lib/linux-api/Cargo.toml

@@ -6,28 +6,28 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [features]
-default = ["rustix"]
 std = []
 rustix = ["dep:rustix"]
+c_bindings = ["dep:shadow-build-common", "dep:cbindgen"]
 
 [dependencies]
 bitflags = "2.4.1"
 log = { version = "0.4.20", default-features = false }
 shadow-pod = { path = "../pod" }
 static_assertions = "1.1.0"
 vasi = { path = "../vasi" }
-num_enum = { version = "0.7.1", default-features=false }
+num_enum = { version = "0.7.1", default-features = false }
 memoffset = "0.9.0"
 bytemuck = "1.14.0"
 linux-syscall = "1.0.0"
 linux-errno = "1.0.1"
 naked-function = "0.1.5"
 linux-raw-sys = "0.6.3"
-rustix = { optional=true, version = "0.38.28", default-features=false, features = ["process"] }
+rustix = { optional = true, version = "0.38.28", default-features = false, features = ["process"] }
 
 [dev-dependencies]
 rustix = { version = "0.38.28", default-features=false, features = ["thread", "process", "time"] }
 
 [build-dependencies]
-shadow-build-common = { path = "../shadow-build-common" }
-cbindgen = { version = "0.26.0", default_features = false }
+shadow-build-common = { optional = true, path = "../shadow-build-common", features = ["cbindgen"] }
+cbindgen = { optional = true, version = "0.26.0", default_features = false }

src/lib/linux-api/build.rs

@@ -1,5 +1,7 @@
+#[cfg(feature = "c_bindings")]
 use shadow_build_common::ShadowBuildCommon;
 
+#[cfg(feature = "c_bindings")]
 fn run_cbindgen(build_common: &ShadowBuildCommon) {
     let base_config = build_common.cbindgen_base_config();
     let crate_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
@@ -29,7 +31,10 @@ fn run_cbindgen(build_common: &ShadowBuildCommon) {
 }
 
 fn main() {
-    let build_common =
-        shadow_build_common::ShadowBuildCommon::new(std::path::Path::new("../../.."), None);
-    run_cbindgen(&build_common);
+    #[cfg(feature = "c_bindings")]
+    {
+        let build_common =
+            shadow_build_common::ShadowBuildCommon::new(std::path::Path::new("../../.."), None);
+        run_cbindgen(&build_common);
+    }
 }

src/lib/log-c2rust/Cargo.toml

@@ -15,5 +15,5 @@ va_list = { version = "0.1.4", default-features = false }
 
 [build-dependencies]
 cc = { version = "1.0", features = ["parallel"] }
-shadow-build-common = { path = "../shadow-build-common" }
+shadow-build-common = { path = "../shadow-build-common", features = ["cbindgen"] }
 cbindgen = { version = "0.26.0", default_features = false }

src/lib/logger/Cargo.toml

@@ -13,8 +13,8 @@ cc = { version = "1.0", features = ["parallel"] }
 bindgen = { version = "0.69.1" }
 # Needs to be a build-dependency as well for its generated header files
 # to be present, which our C build needs.
-linux-api = { path = "../linux-api" }
-shadow-build-common = { path = "../shadow-build-common" }
+linux-api = { path = "../linux-api", features = ["c_bindings"] }
+shadow-build-common = { path = "../shadow-build-common", features = ["bindgen"] }
 
 [lib]
 path = "src/lib.rs"

src/lib/shadow-build-common/Cargo.toml

@@ -5,9 +5,13 @@ edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+bindgen = ["dep:bindgen"]
+cbindgen = ["dep:cbindgen"]
+
 [dependencies]
-bindgen = { version = "0.69.1" }
-cbindgen = { version = "0.26.0", default_features = false }
+bindgen = { optional = true, version = "0.69.1" }
+cbindgen = { optional = true, version = "0.26.0", default_features = false }
 cc = { version = "1.0", features = ["parallel"] }
 system-deps = "6.2"
 

src/lib/shadow-build-common/src/lib.rs

@@ -73,6 +73,7 @@ impl ShadowBuildCommon {
         b
     }
 
+    #[cfg(feature = "bindgen")]
     pub fn bindgen_builder(&self) -> bindgen::Builder {
         let mut builder = bindgen::Builder::default()
             // Tell cargo to invalidate the built crate whenever any of the
@@ -94,6 +95,7 @@ impl ShadowBuildCommon {
         builder
     }
 
+    #[cfg(feature = "cbindgen")]
     pub fn cbindgen_base_config(&self) -> cbindgen::Config {
         let header = "
 /*
@@ -143,6 +145,7 @@ impl ShadowBuildCommon {
     }
 }
 
+#[cfg(feature = "cbindgen")]
 pub trait CBindgenExt {
     fn get_mut(&mut self) -> &mut cbindgen::Config;
 
@@ -169,6 +172,7 @@ pub trait CBindgenExt {
     }
 }
 
+#[cfg(feature = "cbindgen")]
 impl CBindgenExt for cbindgen::Config {
     fn get_mut(&mut self) -> &mut cbindgen::Config {
         self

src/lib/shadow-shim-helper-rs/Cargo.toml

@@ -27,7 +27,7 @@ bytemuck = "1.14.0"
 
 [build-dependencies]
 cc = { version = "1.0", features = ["parallel"] }
-shadow-build-common = { path = "../shadow-build-common" }
+shadow-build-common = { path = "../shadow-build-common", features = ["cbindgen"] }
 system-deps = "6.2"
 cbindgen = { version = "0.26.0", default_features = false }
 

src/lib/shim/Cargo.toml

@@ -14,7 +14,7 @@ perf_timers = []
 [dependencies]
 formatting-nostd = { path = "../formatting-nostd" }
 libc = { version = "0.2", default-features = false }
-linux-api = { path = "../linux-api"}
+linux-api = { path = "../linux-api", features = ["rustix"] }
 num_enum = { version = "0.7.1", default-features=false }
 shadow-shim-helper-rs = { path = "../shadow-shim-helper-rs" }
 shadow_shmem = { path = "../shmem" }
@@ -37,7 +37,7 @@ test-log = "0.2.14"
 bindgen = { version = "0.69.1" }
 cbindgen = { version = "0.26.0", default_features = false }
 cc = { version = "1.0", features = ["parallel"] }
-shadow-build-common = { path = "../shadow-build-common" }
+shadow-build-common = { path = "../shadow-build-common", features = ["bindgen", "cbindgen"] }
 # Building the C code from this crate's build script requires
 # that these bindings have been generated.
 shadow-shim-helper-rs = { path = "../shadow-shim-helper-rs" }

src/lib/tsc/Cargo.toml

@@ -11,7 +11,7 @@ logger = { path = "../logger" }
 [build-dependencies]
 bindgen = { version = "0.69.1" }
 cc = { version = "1.0", features = ["parallel"] }
-shadow-build-common = { path = "../shadow-build-common" }
+shadow-build-common = { path = "../shadow-build-common", features = ["bindgen", "cbindgen"] }
 system-deps = "6.2"
 cbindgen = { version = "0.26.0", default_features = false }
 

src/lib/vasi-sync/Cargo.toml

@@ -6,18 +6,18 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-num_enum = { version = "0.7.1", default-features=false }
-rustix = { version = "0.38.28", default-features = false, features=["fs", "thread", "process"] }
+num_enum = { version = "0.7.1", default-features = false }
+rustix = { version = "0.38.28", default-features = false, features = ["fs", "thread", "process"] }
 static_assertions = "1.1.0"
 vasi = { path = "../vasi" }
-rustc-hash = { version = "1.1.0", default-features=false }
+rustc-hash = { version = "1.1.0", default-features = false }
 
 [dev-dependencies]
 criterion = "0.5.1"
 rand = "0.8.5"
-rustix = { version = "0.38.28", default-features = false, features=["process"] }
+rustix = { version = "0.38.28", default-features = false, features = ["process"] }
 libc = "0.2"
-nix =  "0.27.1"
+nix = "0.27.1"
 
 [target.'cfg(loom)'.dependencies]
 loom = { version = "0.7", features = ["checkpoint"] }

src/main/Cargo.toml

@@ -10,7 +10,7 @@ path = "lib.rs"
 crate-type = ["rlib", "staticlib"]
 
 [dependencies]
-anyhow = { version = "1.0.78", features = ["backtrace"] }
+anyhow = "1.0.78"
 atomic_refcell = "0.1"
 backtrace = "0.3.69"
 bitflags = "2.4"
@@ -22,7 +22,7 @@ clap = { version = "4.5.0", features = ["derive", "wrap_help"] }
 crossbeam = "0.8.3"
 gml-parser = { path = "../lib/gml-parser" }
 libc = "0.2"
-linux-api = { path = "../lib/linux-api", features = ["std"] }
+linux-api = { path = "../lib/linux-api", features = ["c_bindings", "std"] }
 # don't log debug or trace levels in release mode
 log = { version = "0.4", features = ["release_max_level_debug"] }
 log-c2rust = { path = "../lib/log-c2rust" }
@@ -71,7 +71,7 @@ bytemuck = "1.14.0"
 perf_timers = []
 
 [build-dependencies]
-shadow-build-common = { path = "../lib/shadow-build-common" }
+shadow-build-common = { path = "../lib/shadow-build-common", features = ["bindgen", "cbindgen"] }
 bindgen = { version = "0.69.1" }
 cbindgen = { version = "0.26.0", default_features = false }
 cc = { version = "1.0", features = ["parallel"] }

src/test/Cargo.toml

@@ -217,14 +217,14 @@ name = "test_prctl"
 path = "prctl/test_prctl.rs"
 
 [dependencies]
-anyhow = { version = "1.0.78", features = ["backtrace"] }
+anyhow = "1.0.78"
 formatting-nostd = { path = "../lib/formatting-nostd" }
 libc = "0.2"
-linux-api = { path = "../lib/linux-api", features  = ["std"] }
+linux-api = { path = "../lib/linux-api", features = ["rustix", "std"] }
 neli = "0.6.4"
 nix = { version = "0.26.4", features = ["event", "feature", "fs", "poll", "process", "sched", "signal", "socket", "uio"] }
-rand = { version="0.8.5", features=["small_rng"] }
-rustix = { version = "0.38.28", default-features=false, features=["fs", "mm", "pipe", "time", "thread"]}
+rand = { version = "0.8.5", features = ["small_rng"] }
+rustix = { version = "0.38.28", default-features = false, features = ["fs", "mm", "pipe", "time", "thread"] }
 signal-hook = "0.3.17"
 once_cell = "1.19.0"
 vasi-sync = { path = "../lib/vasi-sync" }