clif-util: try both global and target-dependent settings when parsing --set flags;

cranelift/src/utils.rs

@@ -3,7 +3,7 @@
 use cranelift_codegen::isa;
 use cranelift_codegen::isa::TargetIsa;
 use cranelift_codegen::settings::{self, FlagsOrIsa};
-use cranelift_reader::{parse_options, Location};
+use cranelift_reader::{parse_options, Location, ParseError, ParseOptionError};
 use std::fs::File;
 use std::io::{self, Read};
 use std::path::Path;
@@ -46,12 +46,21 @@ pub fn parse_sets_and_triple(
     flag_triple: &str,
 ) -> Result<OwnedFlagsOrIsa, String> {
     let mut flag_builder = settings::builder();
-    parse_options(
+
+    // Collect unknown system-wide settings, so we can try to parse them as target specific
+    // settings, if a target is defined.
+    let mut unknown_settings = Vec::new();
+    match parse_options(
         flag_set.iter().map(|x| x.as_str()),
         &mut flag_builder,
         Location { line_number: 0 },
-    )
-    .map_err(|err| err.to_string())?;
+    ) {
+        Err(ParseOptionError::UnknownFlag { name, .. }) => {
+            unknown_settings.push(name);
+        }
+        Err(ParseOptionError::Generic(err)) => return Err(err.to_string()),
+        Ok(()) => {}
+    }
 
     let mut words = flag_triple.trim().split_whitespace();
     // Look for `target foo`.
@@ -60,6 +69,7 @@ pub fn parse_sets_and_triple(
             Ok(triple) => triple,
             Err(parse_error) => return Err(parse_error.to_string()),
         };
+
         let mut isa_builder = isa::lookup(triple).map_err(|err| match err {
             isa::LookupError::SupportDisabled => {
                 format!("support for triple '{}' is disabled", triple_name)
@@ -69,14 +79,29 @@ pub fn parse_sets_and_triple(
                 triple_name
             ),
         })?;
+
+        // Try to parse system-wide unknown settings as target-specific settings.
+        parse_options(
+            unknown_settings.iter().map(|x| x.as_str()),
+            &mut isa_builder,
+            Location { line_number: 0 },
+        )
+        .map_err(|err| ParseError::from(err).to_string())?;
+
         // Apply the ISA-specific settings to `isa_builder`.
         parse_options(words, &mut isa_builder, Location { line_number: 0 })
-            .map_err(|err| err.to_string())?;
+            .map_err(|err| ParseError::from(err).to_string())?;
 
         Ok(OwnedFlagsOrIsa::Isa(
             isa_builder.finish(settings::Flags::new(flag_builder)),
         ))
     } else {
+        if !unknown_settings.is_empty() {
+            return Err(format!(
+                "unknown settings: '{}'",
+                unknown_settings.join("', '")
+            ));
+        }
         Ok(OwnedFlagsOrIsa::Flags(settings::Flags::new(flag_builder)))
     }
 }