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/config-schema.json

@@ -25,6 +25,20 @@
         }
       ]
     },
+    {
+      "id": "analyzeDataFlow",
+      "type": "boolean",
+      "default": false,
+      "name": "(Experimental) Perform data flow analysis",
+      "description": "Use data flow analysis to display known information about register contents where possible"
+    },
+    {
+      "id": "showDataFlow",
+      "type": "boolean",
+      "default": true,
+      "name": "Show data flow",
+      "description": "Show data flow analysis results in place of register name where present"
+    },
     {
       "id": "spaceBetweenArgs",
       "type": "boolean",
@@ -264,7 +278,8 @@
       "id": "ppc",
       "name": "PowerPC",
       "properties": [
-        "ppc.calculatePoolRelocations"
+        "ppc.calculatePoolRelocations",
+        "analyzeDataFlow"
       ]
     },
     {