Refactor set/isa parsing into a utility function.

cranelift/src/utils.rs

@@ -4,13 +4,16 @@ use cretonne::ir::entities::AnyEntity;
 use cretonne::{ir, verifier};
 use cretonne::result::CtonError;
 use cretonne::isa::TargetIsa;
+use cretonne::settings::{self, FlagsOrIsa};
+use cretonne::isa;
+use cton_reader::{parse_options, Location};
 use std::fmt::Write;
 use std::fs::File;
-use std::io::{Result, Read};
+use std::io::{self, Read};
 use std::path::Path;
 
 /// Read an entire file into a string.
-pub fn read_to_string<P: AsRef<Path>>(path: P) -> Result<String> {
+pub fn read_to_string<P: AsRef<Path>>(path: P) -> io::Result<String> {
     let mut file = File::open(path)?;
     let mut buffer = String::new();
     file.read_to_string(&mut buffer)?;
@@ -62,6 +65,49 @@ pub fn pretty_error(func: &ir::Function, isa: Option<&TargetIsa>, err: CtonError
     }
 }
 
+/// Like FlagsOrIsa, but holds ownership.
+pub enum OwnedFlagsOrIsa {
+    Flags(settings::Flags),
+    Isa(Box<TargetIsa>),
+}
+
+impl OwnedFlagsOrIsa {
+    /// Produce a FlagsOrIsa reference.
+    pub fn as_fisa(&self) -> FlagsOrIsa {
+        match *self {
+            OwnedFlagsOrIsa::Flags(ref flags) => FlagsOrIsa::from(flags),
+            OwnedFlagsOrIsa::Isa(ref isa) => FlagsOrIsa::from(&**isa),
+        }
+    }
+}
+
+/// Parse "set" and "isa" commands.
+pub fn parse_sets_and_isa(
+    flag_set: Vec<String>,
+    flag_isa: String,
+) -> Result<OwnedFlagsOrIsa, String> {
+    let mut flag_builder = settings::builder();
+    parse_options(
+        flag_set.iter().map(|x| x.as_str()),
+        &mut flag_builder,
+        &Location { line_number: 0 },
+    ).map_err(|err| err.to_string())?;
+
+    let mut words = flag_isa.trim().split_whitespace();
+    // Look for `isa foo`.
+    if let Some(isa_name) = words.next() {
+        let isa_builder = isa::lookup(isa_name).map_err(|err| match err {
+            isa::LookupError::Unknown => format!("unknown ISA '{}'", isa_name),
+            isa::LookupError::Unsupported => format!("support for ISA '{}' not enabled", isa_name),
+        })?;
+        Ok(OwnedFlagsOrIsa::Isa(
+            isa_builder.finish(settings::Flags::new(&flag_builder)),
+        ))
+    } else {
+        Ok(OwnedFlagsOrIsa::Flags(settings::Flags::new(&flag_builder)))
+    }
+}
+
 #[test]
 fn test_match_directive() {
     assert_eq!(match_directive("; foo: bar  ", "foo:"), Some("bar"));