Allow controlling the Cargo profile used for macro expansion

If there's already a release build, it's better for cbindgen to reuse
the build artifacts from that to expand macros rather than starting
from scratch with a debug build. Controlled with

  --profile (debug|release)

as well as parse.expand.profile in cbindgen.toml, though hardcoding a
profile in a config file seems unlikely.

Cargo.toml

@@ -31,6 +31,9 @@ version = "1.0.3"
 default-features = false
 features = ["clone-impls", "extra-traits", "full", "parsing", "printing"]
 
+[dev-dependencies]
+serial_test = "0.5.0"
+
 [features]
 default =  ["clap"]
 

src/bindgen/builder.rs

@@ -6,7 +6,7 @@ use std::path;
 
 use crate::bindgen::bindings::Bindings;
 use crate::bindgen::cargo::Cargo;
-use crate::bindgen::config::{Braces, Config, Language, Style};
+use crate::bindgen::config::{Braces, Config, Language, Profile, Style};
 use crate::bindgen::error::Error;
 use crate::bindgen::library::Library;
 use crate::bindgen::parser::{self, Parse};
@@ -225,6 +225,12 @@ impl Builder {
         self
     }
 
+    #[allow(unused)]
+    pub fn with_parse_expand_profile(mut self, profile: Profile) -> Builder {
+        self.config.parse.expand.profile = profile;
+        self
+    }
+
     #[allow(unused)]
     pub fn with_documentation(mut self, documentation: bool) -> Builder {
         self.config.documentation = documentation;

src/bindgen/cargo/cargo.rs

@@ -11,6 +11,7 @@ use crate::bindgen::cargo::cargo_metadata::{self, Metadata};
 use crate::bindgen::cargo::cargo_toml;
 use crate::bindgen::error::Error;
 use crate::bindgen::ir::Cfg;
+pub(crate) use cargo_expand::Profile;
 
 /// Parse a dependency string used in Cargo.lock
 fn parse_dep_string(dep_string: &str) -> (&str, Option<&str>) {
@@ -233,6 +234,7 @@ impl Cargo {
         expand_all_features: bool,
         expand_default_features: bool,
         expand_features: &Option<Vec<String>>,
+        profile: Profile,
     ) -> Result<String, cargo_expand::Error> {
         cargo_expand::expand(
             &self.manifest_path,
@@ -242,6 +244,7 @@ impl Cargo {
             expand_all_features,
             expand_default_features,
             expand_features,
+            profile,
         )
     }
 }

src/bindgen/cargo/cargo_expand.rs

@@ -24,6 +24,14 @@ pub enum Error {
     Compile(String),
 }
 
+/// Which Cargo profile (group) to use when expanding macros.
+pub enum Profile {
+    /// Do not pass `--release` when expanding macros
+    Debug,
+    /// Pass `--release` when expanding macros
+    Release,
+}
+
 impl From<io::Error> for Error {
     fn from(err: io::Error) -> Self {
         Error::Io(err)
@@ -65,6 +73,7 @@ pub fn expand(
     expand_all_features: bool,
     expand_default_features: bool,
     expand_features: &Option<Vec<String>>,
+    profile: Profile,
 ) -> Result<String, Error> {
     let cargo = env::var("CARGO").unwrap_or_else(|_| String::from("cargo"));
     let mut cmd = Command::new(cargo);
@@ -108,6 +117,12 @@ pub fn expand(
     if !expand_default_features {
         cmd.arg("--no-default-features");
     }
+    match profile {
+        Profile::Debug => {}
+        Profile::Release => {
+            cmd.arg("--release");
+        }
+    }
     cmd.arg("-p");
     let mut package = crate_name.to_owned();
     if let Some(version) = version {

src/bindgen/config.rs

@@ -668,6 +668,27 @@ pub struct MacroExpansionConfig {
     pub bitflags: bool,
 }
 
+/// Controls which Cargo profile is used for macro expansion.
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub enum Profile {
+    Debug,
+    Release,
+}
+
+impl FromStr for Profile {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Profile, Self::Err> {
+        match s {
+            "debug" | "Debug" => Ok(Profile::Debug),
+            "release" | "Release" => Ok(Profile::Release),
+            _ => Err(format!("Unrecognized Profile: '{}'.", s)),
+        }
+    }
+}
+
+deserialize_enum_str!(Profile);
+
 /// Settings to apply when running `rustc --pretty=expanded`
 #[derive(Debug, Clone, Deserialize)]
 #[serde(rename_all = "snake_case")]
@@ -683,6 +704,8 @@ pub struct ParseExpandConfig {
     /// List of features to use when expanding. Combines with `default_features` like in
     /// `Cargo.toml`.
     pub features: Option<Vec<String>>,
+    /// Controls whether or not to pass `--release` when expanding.
+    pub profile: Profile,
 }
 
 impl Default for ParseExpandConfig {
@@ -692,6 +715,7 @@ impl Default for ParseExpandConfig {
             all_features: false,
             default_features: true,
             features: None,
+            profile: Profile::Debug,
         }
     }
 }
@@ -723,6 +747,7 @@ fn retrocomp_parse_expand_config_deserialize<'de, D: Deserializer<'de>>(
                 all_features: true,
                 default_features: true,
                 features: None,
+                profile: Profile::Debug,
             })
         }
 

src/bindgen/mod.rs

@@ -60,5 +60,6 @@ pub(crate) use self::cargo::*;
 
 pub use self::bindings::Bindings;
 pub use self::builder::Builder;
+pub use self::config::Profile; // disambiguate with cargo::Profile
 pub use self::config::*;
 pub use self::error::Error;

src/bindgen/parser.rs

@@ -9,8 +9,9 @@ use std::io::Read;
 use std::path::{Path as FilePath, PathBuf as FilePathBuf};
 
 use crate::bindgen::bitflags;
+use crate::bindgen::cargo;
 use crate::bindgen::cargo::{Cargo, PackageRef};
-use crate::bindgen::config::{Config, ParseConfig};
+use crate::bindgen::config::{Config, ParseConfig, Profile};
 use crate::bindgen::error::Error;
 use crate::bindgen::ir::{
     AnnotationSet, Cfg, Constant, Documentation, Enum, Function, GenericParams, ItemMap,
@@ -191,6 +192,10 @@ impl<'a> Parser<'a> {
                         self.config.parse.expand.all_features,
                         self.config.parse.expand.default_features,
                         &self.config.parse.expand.features,
+                        match self.config.parse.expand.profile {
+                            Profile::Debug => cargo::Profile::Debug,
+                            Profile::Release => cargo::Profile::Release,
+                        },
                     )
                     .map_err(|x| Error::CargoExpand(pkg.name.clone(), x))?;
                 let i = syn::parse_file(&s).map_err(|x| Error::ParseSyntaxError {

src/main.rs

@@ -5,6 +5,7 @@
 use std::env;
 use std::io;
 use std::path::{Path, PathBuf};
+use std::str::FromStr;
 
 extern crate clap;
 #[macro_use]
@@ -24,7 +25,7 @@ use clap::{App, Arg, ArgMatches};
 mod bindgen;
 mod logging;
 
-use crate::bindgen::{Bindings, Builder, Cargo, Config, Error, Language, Style};
+use crate::bindgen::{Bindings, Builder, Cargo, Config, Error, Language, Profile, Style};
 
 fn apply_config_overrides<'a>(config: &mut Config, matches: &ArgMatches<'a>) {
     // We allow specifying a language to override the config default. This is
@@ -61,6 +62,16 @@ fn apply_config_overrides<'a>(config: &mut Config, matches: &ArgMatches<'a>) {
         }
     }
 
+    if let Some(profile) = matches.value_of("profile") {
+        config.parse.expand.profile = match Profile::from_str(profile) {
+            Ok(p) => p,
+            Err(e) => {
+                error!("{}", e);
+                return;
+            }
+        }
+    }
+
     if matches.is_present("d") {
         config.parse.parse_deps = true;
     }
@@ -226,6 +237,16 @@ fn main() {
                 )
                 .required(false),
         )
+        .arg(
+            Arg::with_name("profile")
+                .long("profile")
+                .value_name("PROFILE")
+                .help(
+                    "Specify the profile to use when expanding macros. \
+                     Has no effect otherwise."
+                )
+                .possible_values(&["Debug", "debug", "Release", "release"]),
+        )
         .arg(
             Arg::with_name("quiet")
                 .short("q")