Diff reloc data by display string instead of raw bytes

This is to handle data symbols that contain multiple values in them at once, such as stringBase. If you compare the target symbol's bytes directly, then any part of the symbol having different bytes will cause *all* relocations to that symbol to show as a diff, even if the specific string being accessed is the same.

Author: LagoLunatic

objdiff-core/src/arch/mod.rs

@@ -156,6 +156,17 @@ pub trait ObjArch: Send + Sync {
         Some(format!("Bytes: {:#x?}", bytes))
     }
 
+    fn display_ins_data(&self, ins: &ObjIns) -> Option<String> {
+        let reloc = ins.reloc.as_ref()?;
+        if reloc.addend >= 0 && reloc.target.bytes.len() > reloc.addend as usize {
+            self.guess_data_type(ins).and_then(|ty| {
+                self.display_data_type(ty, &reloc.target.bytes[reloc.addend as usize..])
+            })
+        } else {
+            None
+        }
+    }
+
     // Downcast methods
     #[cfg(feature = "ppc")]
     fn ppc(&self) -> Option<&ppc::ObjArchPpc> { None }

objdiff-core/src/diff/code.rs

@@ -10,7 +10,7 @@ use crate::{
         ObjSymbolDiff,
     },
     obj::{
-        ObjInfo, ObjInsArg, ObjReloc, ObjSection, ObjSymbol, ObjSymbolFlags, ObjSymbolKind,
+        ObjInfo, ObjIns, ObjInsArg, ObjReloc, ObjSection, ObjSymbol, ObjSymbolFlags, ObjSymbolKind,
         SymbolRef,
     },
 };
@@ -218,10 +218,13 @@ fn reloc_eq(
     config: &DiffObjConfig,
     left_obj: &ObjInfo,
     right_obj: &ObjInfo,
-    left_reloc: Option<&ObjReloc>,
-    right_reloc: Option<&ObjReloc>,
+    left_ins: Option<&ObjIns>,
+    right_ins: Option<&ObjIns>,
 ) -> bool {
-    let (Some(left), Some(right)) = (left_reloc, right_reloc) else {
+    let (Some(left_ins), Some(right_ins)) = (left_ins, right_ins) else {
+        return false;
+    };
+    let (Some(left), Some(right)) = (&left_ins.reloc, &right_ins.reloc) else {
         return false;
     };
     if left.flags != right.flags {
@@ -241,7 +244,8 @@ fn reloc_eq(
                     || config.relax_shifted_data_diffs)
                 && (left.target.kind != ObjSymbolKind::Object
                     || right.target.name.starts_with("...")
-                    || left.target.bytes == right.target.bytes)
+                    || left_obj.arch.display_ins_data(left_ins)
+                        == left_obj.arch.display_ins_data(right_ins))
         }
         (Some(_), None) => false,
         (None, Some(_)) => {
@@ -279,8 +283,8 @@ fn arg_eq(
                     config,
                     left_obj,
                     right_obj,
-                    left_diff.ins.as_ref().and_then(|i| i.reloc.as_ref()),
-                    right_diff.ins.as_ref().and_then(|i| i.reloc.as_ref()),
+                    left_diff.ins.as_ref(),
+                    right_diff.ins.as_ref(),
                 )
         }
         ObjInsArg::BranchDest(_) => match right {

objdiff-gui/src/views/function_diff.rs

@@ -149,12 +149,8 @@ fn ins_hover_ui(
                     appearance.highlight_color,
                     format!("Size: {:x}", reloc.target.size),
                 );
-                if reloc.addend >= 0 && reloc.target.bytes.len() > reloc.addend as usize {
-                    if let Some(s) = obj.arch.guess_data_type(ins).and_then(|ty| {
-                        obj.arch.display_data_type(ty, &reloc.target.bytes[reloc.addend as usize..])
-                    }) {
-                        ui.colored_label(appearance.highlight_color, s);
-                    }
+                if let Some(s) = obj.arch.display_ins_data(ins) {
+                    ui.colored_label(appearance.highlight_color, s);
                 }
             } else {
                 ui.colored_label(appearance.highlight_color, "Extern".to_string());