Better detection of features for USDT (#295)

Author: bnaecker

Cargo.toml

@@ -123,6 +123,7 @@ tracing-bunyan-formatter = "0.3.3"
 tracing-subscriber = "0.3.14"
 usdt = "0.3.2"
 uuid = "1.0.0"
+version_check = "0.9"
 viona_api = { path = "crates/viona-api" }
 vte = "0.10.1"
 

bin/propolis-server/Cargo.toml

@@ -60,6 +60,9 @@ slog = { workspace = true, features = [ "max_level_trace", "release_max_level_de
 expectorate.workspace = true
 mockall.workspace = true
 
+[build-dependencies]
+version_check.workspace = true
+
 [features]
 default = ["dtrace-probes"]
 dtrace-probes = ["propolis/dtrace-probes", "dropshot/usdt-probes"]

bin/propolis-server/build.rs

@@ -0,0 +1,16 @@
+// Copyright 2023 Oxide Computer Company
+
+fn main() {
+    println!("cargo:rerun-if-changed=build.rs");
+
+    if !version_check::is_min_version("1.59").unwrap_or(false) {
+        println!("cargo:rustc-cfg=usdt_need_asm");
+    }
+
+    #[cfg(target_os = "macos")]
+    if version_check::supports_feature("asm_sym").unwrap_or(false)
+        && !version_check::is_min_version("1.67").unwrap_or(false)
+    {
+        println!("cargo:rustc-cfg=usdt_need_asm_sym");
+    }
+}

bin/propolis-server/src/main.rs

@@ -1,8 +1,6 @@
 // Required for USDT
-#![cfg_attr(
-    all(feature = "dtrace-probes", target_os = "macos"),
-    feature(asm_sym)
-)]
+#![cfg_attr(usdt_need_asm, feature(asm))]
+#![cfg_attr(all(target_os = "macos", usdt_need_asm_sym), feature(asm_sym))]
 
 use anyhow::anyhow;
 use clap::Parser;

lib/propolis/Cargo.toml

@@ -51,6 +51,9 @@ slog-term.workspace = true
 slog-async.workspace = true
 rand.workspace = true
 
+[build-dependencies]
+version_check.workspace = true
+
 [features]
 default = ["dtrace-probes"]
 dtrace-probes = ["usdt/asm"]

lib/propolis/build.rs

@@ -0,0 +1,16 @@
+// Copyright 2023 Oxide Computer Company
+
+fn main() {
+    println!("cargo:rerun-if-changed=build.rs");
+
+    if !version_check::is_min_version("1.59").unwrap_or(false) {
+        println!("cargo:rustc-cfg=usdt_need_asm");
+    }
+
+    #[cfg(target_os = "macos")]
+    if version_check::supports_feature("asm_sym").unwrap_or(false)
+        && !version_check::is_min_version("1.67").unwrap_or(false)
+    {
+        println!("cargo:rustc-cfg=usdt_need_asm_sym");
+    }
+}

lib/propolis/src/lib.rs

@@ -1,9 +1,7 @@
 #![allow(clippy::style)]
 #![allow(clippy::drop_non_drop)]
-#![cfg_attr(
-    all(feature = "dtrace-probes", target_os = "macos"),
-    feature(asm_sym)
-)]
+#![cfg_attr(usdt_need_asm, feature(asm))]
+#![cfg_attr(all(target_os = "macos", usdt_need_asm_sym), feature(asm_sym))]
 
 pub extern crate bhyve_api;
 pub extern crate usdt;