Set lto = "thin" for metadata build to fix linkme on macOS

crates/build/src/lib.rs

@@ -60,8 +60,11 @@ pub use self::{
         OptimizationResult,
     },
     workspace::{
+        Lto,
         Manifest,
         ManifestPath,
+        OptLevel,
+        PanicStrategy,
         Profile,
         Workspace,
     },

crates/build/src/metadata.rs

@@ -26,8 +26,10 @@ use crate::{
     BuildMode,
     BuildSteps,
     Features,
+    Lto,
     Network,
     OptimizationPasses,
+    Profile,
     UnstableFlags,
     Verbosity,
 };
@@ -188,7 +190,10 @@ pub(crate) fn execute(
             .with_root_package_manifest(|manifest| {
                 manifest
                     .with_added_crate_type("rlib")?
-                    .with_profile_release_lto(false)?
+                    .with_profile_release_defaults(Profile {
+                        lto: Some(Lto::Thin),
+                        ..Profile::default()
+                    })?
                     .with_empty_workspace();
                 Ok(())
             })?

crates/build/src/workspace/manifest.rs

@@ -214,16 +214,6 @@ impl Manifest {
             .map(Into::into)
     }
 
-    /// Set `[profile.release]` lto flag
-    pub fn with_profile_release_lto(&mut self, enabled: bool) -> Result<&mut Self> {
-        let lto = self
-            .profile_release_table_mut()?
-            .entry("lto")
-            .or_insert(enabled.into());
-        *lto = enabled.into();
-        Ok(self)
-    }
-
     /// Set preferred defaults for the `[profile.release]` section
     ///
     /// # Note

crates/build/src/workspace/mod.rs

@@ -24,7 +24,12 @@ pub use self::{
         Manifest,
         ManifestPath,
     },
-    profile::Profile,
+    profile::{
+        Lto,
+        OptLevel,
+        PanicStrategy,
+        Profile,
+    },
 };
 
 use anyhow::Result;

crates/build/src/workspace/profile.rs

@@ -16,25 +16,29 @@
 
 use toml::value;
 
-/// Subset of cargo profile settings to configure defaults for building contracts
+/// Subset of cargo profile settings to configure defaults for building contracts.
+///
+/// All fields are optional, and if not set, the default value from cargo will be used.
+/// See https://doc.rust-lang.org/cargo/reference/profiles.html#default-profiles.
+#[derive(Default)]
 pub struct Profile {
-    opt_level: OptLevel,
-    lto: Lto,
+    pub opt_level: Option<OptLevel>,
+    pub lto: Option<Lto>,
     // `None` means use rustc default.
-    codegen_units: Option<u32>,
-    overflow_checks: bool,
-    panic: PanicStrategy,
+    pub codegen_units: Option<u32>,
+    pub overflow_checks: Option<bool>,
+    pub panic: Option<PanicStrategy>,
 }
 
 impl Profile {
     /// The preferred set of defaults for compiling a release build of a contract
     pub fn default_contract_release() -> Profile {
         Profile {
-            opt_level: OptLevel::Z,
-            lto: Lto::Fat,
+            opt_level: Some(OptLevel::Z),
+            lto: Some(Lto::Fat),
             codegen_units: Some(1),
-            overflow_checks: true,
-            panic: PanicStrategy::Abort,
+            overflow_checks: Some(true),
+            panic: Some(PanicStrategy::Abort),
         }
     }
 
@@ -46,18 +50,32 @@ impl Profile {
     ///   - If a profile setting is not defined, the value from this profile instance will
     ///     be added
     pub(super) fn merge(&self, profile: &mut value::Table) {
-        let mut set_value_if_vacant = |key: &'static str, value: value::Value| {
-            if !profile.contains_key(key) {
-                profile.insert(key.into(), value);
+        fn set_value_if_vacant<T>(
+            key: &'static str,
+            value: Option<T>,
+            profile: &mut value::Table,
+        ) where
+            T: Into<value::Value>,
+        {
+            if let Some(value) = value {
+                if !profile.contains_key(key) {
+                    profile.insert(key.into(), value.into());
+                }
             }
-        };
-        set_value_if_vacant("opt-level", self.opt_level.to_toml_value());
-        set_value_if_vacant("lto", self.lto.to_toml_value());
-        if let Some(codegen_units) = self.codegen_units {
-            set_value_if_vacant("codegen-units", codegen_units.into());
         }
-        set_value_if_vacant("overflow-checks", self.overflow_checks.into());
-        set_value_if_vacant("panic", self.panic.to_toml_value());
+        set_value_if_vacant(
+            "opt-level",
+            self.opt_level.map(OptLevel::to_toml_value),
+            profile,
+        );
+        set_value_if_vacant("lto", self.lto.map(Lto::to_toml_value), profile);
+        set_value_if_vacant("codegen-units", self.codegen_units, profile);
+        set_value_if_vacant("overflow-checks", self.overflow_checks, profile);
+        set_value_if_vacant(
+            "panic",
+            self.panic.map(PanicStrategy::to_toml_value),
+            profile,
+        );
     }
 }