Add symbol mapping feature (#118)

This allows users to "map" (or "link") symbols with different names so that they can be compared without having to update either the target or base objects. Symbol mappings are persisted in objdiff.json, so generators will need to ensure that they're preserved when updating. (Example: encounter/dtk-template@d1334bb)

Resolves #117

Author: encounter

Cargo.lock

@@ -13,7 +13,7 @@ strip = "debuginfo"
 codegen-units = 1
 
 [workspace.package]
-version = "2.2.2"
+version = "2.3.0"
 authors = ["Luke Street <luke@street.dev>"]
 edition = "2021"
 license = "MIT OR Apache-2.0"

Cargo.toml

@@ -133,6 +133,13 @@
         },
         "metadata": {
           "ref": "#/$defs/metadata"
+        },
+        "symbol_mappings": {
+          "type": "object",
+          "description": "Manual symbol mappings from target to base.",
+          "additionalProperties": {
+            "type": "string"
+          }
         }
       }
     },

config.schema.json

@@ -102,34 +102,46 @@ pub fn run(args: Args) -> Result<()> {
                     let unit_path =
                         PathBuf::from_str(u).ok().and_then(|p| fs::canonicalize(p).ok());
 
-                    let Some(object) = project_config.objects.iter_mut().find_map(|obj| {
-                        if obj.name.as_deref() == Some(u) {
-                            resolve_paths(obj);
-                            return Some(obj);
-                        }
+                    let Some(object) = project_config
+                        .units
+                        .as_deref_mut()
+                        .unwrap_or_default()
+                        .iter_mut()
+                        .find_map(|obj| {
+                            if obj.name.as_deref() == Some(u) {
+                                resolve_paths(obj);
+                                return Some(obj);
+                            }
 
-                        let up = unit_path.as_deref()?;
+                            let up = unit_path.as_deref()?;
 
-                        resolve_paths(obj);
+                            resolve_paths(obj);
 
-                        if [&obj.base_path, &obj.target_path]
-                            .into_iter()
-                            .filter_map(|p| p.as_ref().and_then(|p| p.canonicalize().ok()))
-                            .any(|p| p == up)
-                        {
-                            return Some(obj);
-                        }
+                            if [&obj.base_path, &obj.target_path]
+                                .into_iter()
+                                .filter_map(|p| p.as_ref().and_then(|p| p.canonicalize().ok()))
+                                .any(|p| p == up)
+                            {
+                                return Some(obj);
+                            }
 
-                        None
-                    }) else {
+                            None
+                        })
+                    else {
                         bail!("Unit not found: {}", u)
                     };
 
                     object
                 } else if let Some(symbol_name) = &args.symbol {
                     let mut idx = None;
                     let mut count = 0usize;
-                    for (i, obj) in project_config.objects.iter_mut().enumerate() {
+                    for (i, obj) in project_config
+                        .units
+                        .as_deref_mut()
+                        .unwrap_or_default()
+                        .iter_mut()
+                        .enumerate()
+                    {
                         resolve_paths(obj);
 
                         if obj
@@ -148,7 +160,7 @@ pub fn run(args: Args) -> Result<()> {
                     }
                     match (count, idx) {
                         (0, None) => bail!("Symbol not found: {}", symbol_name),
-                        (1, Some(i)) => &mut project_config.objects[i],
+                        (1, Some(i)) => &mut project_config.units_mut()[i],
                         (2.., Some(_)) => bail!(
                             "Multiple instances of {} were found, try specifying a unit",
                             symbol_name
@@ -303,7 +315,7 @@ fn find_function(obj: &ObjInfo, name: &str) -> Option<SymbolRef> {
     None
 }
 
-#[allow(dead_code)]
+#[expect(dead_code)]
 struct FunctionDiffUi {
     relax_reloc_diffs: bool,
     left_highlight: HighlightKind,
@@ -758,7 +770,7 @@ impl FunctionDiffUi {
         self.scroll_y += self.per_page / if half { 2 } else { 1 };
     }
 
-    #[allow(clippy::too_many_arguments)]
+    #[expect(clippy::too_many_arguments)]
     fn print_sym(
         &self,
         out: &mut Text<'static>,

objdiff-cli/src/cmd/diff.rs

@@ -94,7 +94,7 @@ fn generate(args: GenerateArgs) -> Result<()> {
     };
     info!(
         "Generating report for {} units (using {} threads)",
-        project.objects.len(),
+        project.units().len(),
         if args.deduplicate { 1 } else { rayon::current_num_threads() }
     );
 
@@ -103,7 +103,7 @@ fn generate(args: GenerateArgs) -> Result<()> {
     let mut existing_functions: HashSet<String> = HashSet::new();
     if args.deduplicate {
         // If deduplicating, we need to run single-threaded
-        for object in &mut project.objects {
+        for object in project.units.as_deref_mut().unwrap_or_default() {
             if let Some(unit) = report_object(
                 object,
                 project_dir,
@@ -116,7 +116,9 @@ fn generate(args: GenerateArgs) -> Result<()> {
         }
     } else {
         let vec = project
-            .objects
+            .units
+            .as_deref_mut()
+            .unwrap_or_default()
             .par_iter_mut()
             .map(|object| {
                 report_object(
@@ -132,7 +134,7 @@ fn generate(args: GenerateArgs) -> Result<()> {
     }
     let measures = units.iter().flat_map(|u| u.measures.into_iter()).collect();
     let mut categories = Vec::new();
-    for category in &project.progress_categories {
+    for category in project.progress_categories() {
         categories.push(ReportCategory {
             id: category.id.clone(),
             name: category.name.clone(),

objdiff-cli/src/cmd/report.rs

@@ -17,8 +17,8 @@ crate-type = ["cdylib", "rlib"]
 
 [features]
 all = ["config", "dwarf", "mips", "ppc", "x86", "arm", "bindings"]
-any-arch = [] # Implicit, used to check if any arch is enabled
-config = ["globset", "semver", "serde_json", "serde_yaml"]
+any-arch = ["bimap"] # Implicit, used to check if any arch is enabled
+config = ["bimap", "globset", "semver", "serde_json", "serde_yaml"]
 dwarf = ["gimli"]
 mips = ["any-arch", "rabbitizer"]
 ppc = ["any-arch", "cwdemangle", "cwextab", "ppc750cl"]
@@ -32,6 +32,7 @@ features = ["all"]
 
 [dependencies]
 anyhow = "1.0"
+bimap = { version = "0.6", features = ["serde"], optional = true }
 byteorder = "1.5"
 filetime = "0.2"
 flagset = "0.4"