Implementation of basic data flow analysis for PowerPC (#212)

* WIP implementation

* * Move flow analysis to dedicated file
* Show string constants inline
* Handle calls to MWCC "sled" helpers which otherwise disrupt flow analysis

* Run cargo insta review

* Apply clippy feedback

* Update more tests.

* Remove std use from ppc flow analysis

* Try to make wasm build work again

* More test changes

* Probably last wasm fix

* Formatting

* Fix WASM

* One more clippy thing

* Fixed display of float constants in a LFS or LFD instruction in case where there is a branch to the subsequent instruction with a different register value.

* On lines with a reloc, only hide Symbol type data flow values rather than all data flow values.

* Formatting

objdiff-core/src/arch/mod.rs

@@ -1,5 +1,8 @@
 use alloc::{borrow::Cow, boxed::Box, format, string::String, vec::Vec};
-use core::{ffi::CStr, fmt, fmt::Debug};
+use core::{
+    ffi::CStr,
+    fmt::{self, Debug},
+};
 
 use anyhow::{Result, bail};
 use encoding_rs::SHIFT_JIS;
@@ -11,8 +14,9 @@ use crate::{
         display::{ContextItem, HoverItem, InstructionPart},
     },
     obj::{
-        InstructionArg, InstructionRef, Object, ParsedInstruction, Relocation, RelocationFlags,
-        ResolvedInstructionRef, ResolvedSymbol, Section, Symbol, SymbolFlagSet, SymbolKind,
+        FlowAnalysisResult, InstructionArg, InstructionRef, Object, ParsedInstruction, Relocation,
+        RelocationFlags, ResolvedInstructionRef, ResolvedSymbol, Section, Symbol, SymbolFlagSet,
+        SymbolKind,
     },
     util::ReallySigned,
 };
@@ -31,6 +35,7 @@ pub mod superh;
 pub mod x86;
 
 /// Represents the type of data associated with an instruction
+#[derive(PartialEq)]
 pub enum DataType {
     Int8,
     Int16,
@@ -335,6 +340,17 @@ pub trait Arch: Send + Sync + Debug {
         Vec::new()
     }
 
+    // Perform detailed data flow analysis
+    fn data_flow_analysis(
+        &self,
+        _obj: &Object,
+        _symbol: &Symbol,
+        _code: &[u8],
+        _relocations: &[Relocation],
+    ) -> Option<Box<dyn FlowAnalysisResult>> {
+        None
+    }
+
     fn implcit_addend(
         &self,
         file: &object::File<'_>,