Move all architecture-specific code into modules

No more scattered relocation handling and
feature checks. Everything will go through
the ObjArch trait, which makes it easier
to add new architectures going forward.

objdiff-core/src/arch/mod.rs

@@ -0,0 +1,47 @@
+use std::borrow::Cow;
+use std::collections::BTreeMap;
+
+use anyhow::{bail, Result};
+use object::{Architecture, Object, Relocation, RelocationFlags};
+
+use crate::{
+    diff::{DiffObjConfig, ProcessCodeResult},
+    obj::{ObjReloc, ObjSection},
+};
+
+#[cfg(feature = "mips")]
+mod mips;
+#[cfg(feature = "ppc")]
+mod ppc;
+#[cfg(feature = "x86")]
+mod x86;
+
+pub trait ObjArch: Send + Sync {
+    fn process_code(
+        &self,
+        config: &DiffObjConfig,
+        data: &[u8],
+        address: u64,
+        relocs: &[ObjReloc],
+        line_info: &Option<BTreeMap<u64, u64>>,
+    ) -> Result<ProcessCodeResult>;
+
+    fn implcit_addend(&self, section: &ObjSection, address: u64, reloc: &Relocation)
+        -> Result<i64>;
+
+    fn demangle(&self, _name: &str) -> Option<String> { None }
+
+    fn display_reloc(&self, flags: RelocationFlags) -> Cow<'static, str>;
+}
+
+pub fn new_arch(object: &object::File) -> Result<Box<dyn ObjArch>> {
+    Ok(match object.architecture() {
+        #[cfg(feature = "ppc")]
+        Architecture::PowerPc => Box::new(ppc::ObjArchPpc::new(object)?),
+        #[cfg(feature = "mips")]
+        Architecture::Mips => Box::new(mips::ObjArchMips::new(object)?),
+        #[cfg(feature = "x86")]
+        Architecture::I386 | Architecture::X86_64 => Box::new(x86::ObjArchX86::new(object)?),
+        arch => bail!("Unsupported architecture: {arch:?}"),
+    })
+}