1 files changed, 107 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_cranelift/src/config.rs b/compiler/rustc_codegen_cranelift/src/config.rs
new file mode 100644
index 000000000..e59a0cb0a
--- /dev/null
+++ b/compiler/rustc_codegen_cranelift/src/config.rs
@@ -0,0 +1,107 @@
+use std::env;
+use std::str::FromStr;
+
+fn bool_env_var(key: &str) -> bool {
+    env::var(key).as_ref().map(|val| &**val) == Ok("1")
+}
+
+/// The mode to use for compilation.
+#[derive(Copy, Clone, Debug)]
+pub enum CodegenMode {
+    /// AOT compile the crate. This is the default.
+    Aot,
+    /// JIT compile and execute the crate.
+    Jit,
+    /// JIT compile and execute the crate, but only compile functions the first time they are used.
+    JitLazy,
+}
+
+impl FromStr for CodegenMode {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "aot" => Ok(CodegenMode::Aot),
+            "jit" => Ok(CodegenMode::Jit),
+            "jit-lazy" => Ok(CodegenMode::JitLazy),
+            _ => Err(format!("Unknown codegen mode `{}`", s)),
+        }
+    }
+}
+
+/// Configuration of cg_clif as passed in through `-Cllvm-args` and various env vars.
+#[derive(Clone, Debug)]
+pub struct BackendConfig {
+    /// Should the crate be AOT compiled or JIT executed.
+    ///
+    /// Defaults to AOT compilation. Can be set using `-Cllvm-args=mode=...`.
+    pub codegen_mode: CodegenMode,
+
+    /// When JIT mode is enable pass these arguments to the program.
+    ///
+    /// Defaults to the value of `CG_CLIF_JIT_ARGS`.
+    pub jit_args: Vec<String>,
+
+    /// Display the time it took to perform codegen for a crate.
+    ///
+    /// Defaults to true when the `CG_CLIF_DISPLAY_CG_TIME` env var is set to 1 or false otherwise.
+    /// Can be set using `-Cllvm-args=display_cg_time=...`.
+    pub display_cg_time: bool,
+
+    /// Enable the Cranelift ir verifier for all compilation passes. If not set it will only run
+    /// once before passing the clif ir to Cranelift for compilation.
+    ///
+    /// Defaults to true when the `CG_CLIF_ENABLE_VERIFIER` env var is set to 1 or when cg_clif is
+    /// compiled with debug assertions enabled or false otherwise. Can be set using
+    /// `-Cllvm-args=enable_verifier=...`.
+    pub enable_verifier: bool,
+
+    /// Don't cache object files in the incremental cache. Useful during development of cg_clif
+    /// to make it possible to use incremental mode for all analyses performed by rustc without
+    /// caching object files when their content should have been changed by a change to cg_clif.
+    ///
+    /// Defaults to true when the `CG_CLIF_DISABLE_INCR_CACHE` env var is set to 1 or false
+    /// otherwise. Can be set using `-Cllvm-args=disable_incr_cache=...`.
+    pub disable_incr_cache: bool,
+}
+
+impl Default for BackendConfig {
+    fn default() -> Self {
+        BackendConfig {
+            codegen_mode: CodegenMode::Aot,
+            jit_args: {
+                let args = std::env::var("CG_CLIF_JIT_ARGS").unwrap_or_else(|_| String::new());
+                args.split(' ').map(|arg| arg.to_string()).collect()
+            },
+            display_cg_time: bool_env_var("CG_CLIF_DISPLAY_CG_TIME"),
+            enable_verifier: cfg!(debug_assertions) || bool_env_var("CG_CLIF_ENABLE_VERIFIER"),
+            disable_incr_cache: bool_env_var("CG_CLIF_DISABLE_INCR_CACHE"),
+        }
+    }
+}
+
+impl BackendConfig {
+    /// Parse the configuration passed in using `-Cllvm-args`.
+    pub fn from_opts(opts: &[String]) -> Result<Self, String> {
+        fn parse_bool(name: &str, value: &str) -> Result<bool, String> {
+            value.parse().map_err(|_| format!("failed to parse value `{}` for {}", value, name))
+        }
+
+        let mut config = BackendConfig::default();
+        for opt in opts {
+            if let Some((name, value)) = opt.split_once('=') {
+                match name {
+                    "mode" => config.codegen_mode = value.parse()?,
+                    "display_cg_time" => config.display_cg_time = parse_bool(name, value)?,
+                    "enable_verifier" => config.enable_verifier = parse_bool(name, value)?,
+                    "disable_incr_cache" => config.disable_incr_cache = parse_bool(name, value)?,
+                    _ => return Err(format!("Unknown option `{}`", name)),
+                }
+            } else {
+                return Err(format!("Invalid option `{}`", opt));
+            }
+        }
+
+        Ok(config)
+    }
+}