Implement diffing relocations within data sections (#154)

* Data view: Show data bytes with differing relocations as a diff

* Data view: Show differing relocations on hover

* Symbol list view: Adjust symbol/section match %s when relocations differ

* Improve data reloc diffing logic

* Don't make reloc diffs cause bytes to show as red or green

* Properly detect byte size of each relocation

* Data view: Add context menu for copying relocation target symbols

* Also show already-matching relocations on hover/right click

* Change font color for nonmatching relocs on hover

Author: LagoLunatic

objdiff-core/src/arch/arm.rs

@@ -276,6 +276,19 @@ impl ObjArch for ObjArchArm {
     fn display_reloc(&self, flags: RelocationFlags) -> Cow<'static, str> {
         Cow::Owned(format!("<{flags:?}>"))
     }
+
+    fn get_reloc_byte_size(&self, flags: RelocationFlags) -> usize {
+        match flags {
+            RelocationFlags::Elf { r_type } => match r_type {
+                elf::R_ARM_ABS32 => 4,
+                elf::R_ARM_REL32 => 4,
+                elf::R_ARM_ABS16 => 2,
+                elf::R_ARM_ABS8 => 1,
+                _ => 1,
+            },
+            _ => 1,
+        }
+    }
 }
 
 #[derive(Clone, Copy, Debug)]

objdiff-core/src/arch/arm64.rs

@@ -173,6 +173,21 @@ impl ObjArch for ObjArchArm64 {
             _ => Cow::Owned(format!("<{flags:?}>")),
         }
     }
+
+    fn get_reloc_byte_size(&self, flags: RelocationFlags) -> usize {
+        match flags {
+            RelocationFlags::Elf { r_type } => match r_type {
+                elf::R_AARCH64_ABS64 => 8,
+                elf::R_AARCH64_ABS32 => 4,
+                elf::R_AARCH64_ABS16 => 2,
+                elf::R_AARCH64_PREL64 => 8,
+                elf::R_AARCH64_PREL32 => 4,
+                elf::R_AARCH64_PREL16 => 2,
+                _ => 1,
+            },
+            _ => 1,
+        }
+    }
 }
 
 struct DisplayCtx<'a> {

objdiff-core/src/arch/mips.rs

@@ -271,6 +271,17 @@ impl ObjArch for ObjArchMips {
             _ => Cow::Owned(format!("<{flags:?}>")),
         }
     }
+
+    fn get_reloc_byte_size(&self, flags: RelocationFlags) -> usize {
+        match flags {
+            RelocationFlags::Elf { r_type } => match r_type {
+                elf::R_MIPS_16 => 2,
+                elf::R_MIPS_32 => 4,
+                _ => 1,
+            },
+            _ => 1,
+        }
+    }
 }
 
 fn push_reloc(args: &mut Vec<ObjInsArg>, reloc: &ObjReloc) -> Result<()> {

objdiff-core/src/arch/mod.rs

@@ -148,6 +148,8 @@ pub trait ObjArch: Send + Sync {
 
     fn display_reloc(&self, flags: RelocationFlags) -> Cow<'static, str>;
 
+    fn get_reloc_byte_size(&self, flags: RelocationFlags) -> usize;
+
     fn symbol_address(&self, symbol: &Symbol) -> u64 { symbol.address() }
 
     fn guess_data_type(&self, _instruction: &ObjIns) -> Option<DataType> { None }

objdiff-core/src/arch/ppc.rs

@@ -202,6 +202,17 @@ impl ObjArch for ObjArchPpc {
         }
     }
 
+    fn get_reloc_byte_size(&self, flags: RelocationFlags) -> usize {
+        match flags {
+            RelocationFlags::Elf { r_type } => match r_type {
+                elf::R_PPC_ADDR32 => 4,
+                elf::R_PPC_UADDR32 => 4,
+                _ => 1,
+            },
+            _ => 1,
+        }
+    }
+
     fn guess_data_type(&self, instruction: &ObjIns) -> Option<super::DataType> {
         if instruction.reloc.as_ref().is_some_and(|r| r.target.name.starts_with("@stringBase")) {
             return Some(DataType::String);

objdiff-core/src/arch/x86.rs

@@ -162,6 +162,19 @@ impl ObjArch for ObjArchX86 {
             _ => Cow::Owned(format!("<{flags:?}>")),
         }
     }
+
+    fn get_reloc_byte_size(&self, flags: RelocationFlags) -> usize {
+        match flags {
+            RelocationFlags::Coff { typ } => match typ {
+                pe::IMAGE_REL_I386_DIR16 => 2,
+                pe::IMAGE_REL_I386_REL16 => 2,
+                pe::IMAGE_REL_I386_DIR32 => 4,
+                pe::IMAGE_REL_I386_REL32 => 4,
+                _ => 1,
+            },
+            _ => 1,
+        }
+    }
 }
 
 fn replace_arg(

objdiff-core/src/diff/code.rs

@@ -196,7 +196,7 @@ fn address_eq(left: &ObjReloc, right: &ObjReloc) -> bool {
     left.target.address as i64 + left.addend == right.target.address as i64 + right.addend
 }
 
-fn section_name_eq(
+pub fn section_name_eq(
     left_obj: &ObjInfo,
     right_obj: &ObjInfo,
     left_orig_section_index: usize,