[meta] Small fixes in the settings generation;

cranelift/codegen/meta/src/gen_settings.rs

@@ -288,7 +288,8 @@ fn gen_descriptors(group: &SettingGroup, fmt: &mut Formatter) {
             });
             fmtln!(fmt, "},");
 
-            descriptor_index_map.insert(SettingOrPreset::Preset(preset), idx);
+            let whole_idx = idx + group.settings.len();
+            descriptor_index_map.insert(SettingOrPreset::Preset(preset), whole_idx);
         }
     });
     fmtln!(fmt, "];");
@@ -304,20 +305,9 @@ fn gen_descriptors(group: &SettingGroup, fmt: &mut Formatter) {
 
     // Generate hash table.
     let mut hash_entries: Vec<SettingOrPreset> = Vec::new();
-    hash_entries.extend(
-        group
-            .settings
-            .iter()
-            .map(|x| SettingOrPreset::Setting(x))
-            .collect::<Vec<SettingOrPreset>>(),
-    );
-    hash_entries.extend(
-        group
-            .presets
-            .iter()
-            .map(|x| SettingOrPreset::Preset(x))
-            .collect::<Vec<SettingOrPreset>>(),
-    );
+    hash_entries.extend(group.settings.iter().map(|x| SettingOrPreset::Setting(x)));
+    hash_entries.extend(group.presets.iter().map(|x| SettingOrPreset::Preset(x)));
+
     let hash_table = generate_table(&hash_entries, |entry| simple_hash(entry.name()));
     fmtln!(fmt, "static HASH_TABLE: [u16; {}] = [", hash_table.len());
     fmt.indent(|fmt| {
@@ -341,7 +331,7 @@ fn gen_descriptors(group: &SettingGroup, fmt: &mut Formatter) {
     fmtln!(
         fmt,
         "static PRESETS: [(u8, u8); {}] = [",
-        group.presets.len()
+        group.presets.len() * (group.settings_size as usize)
     );
     fmt.indent(|fmt| {
         for preset in &group.presets {

cranelift/codegen/meta/src/isa/riscv/mod.rs

@@ -41,7 +41,7 @@ fn define_settings(shared: &SettingGroup) -> SettingGroup {
     setting.add_bool(
         "enable_e",
         "Enable the 'RV32E' instruction set with only 16 registers",
-        true,
+        false,
     );
 
     let shared_enable_atomics = shared.get_bool("enable_atomics");

cranelift/codegen/meta/src/isa/x86/mod.rs

@@ -65,6 +65,8 @@ fn define_settings(shared: &SettingGroup) -> SettingGroup {
         predicate!(!allones_funcaddrs && !is_pic),
     );
 
+    // Presets corresponding to x86 CPUs.
+
     settings.add_preset("baseline", preset!());
     let nehalem = settings.add_preset(
         "nehalem",

cranelift/codegen/meta/src/lib.rs

@@ -59,7 +59,7 @@ pub fn generate(isas: &Vec<isa::Isa>, out_dir: &str) -> Result<(), error::Error>
         gen_settings::generate(
             &isa.settings,
             gen_settings::ParentGroup::Shared,
-            &format!("new_settings-{}", isa.name),
+            &format!("new_settings-{}.rs", isa.name),
             &out_dir,
         )?;
     }