Add new engine based on Ghidra's P-Code IR (angr#2328)

This patch adds a new engine to angr that uses Ghidra's P-Code
intermediate representation. Lifting is handled by the SLEIGH library,
with bindings to Python via pypcode. Symbolic execution is supported for
a majority of ops.

angr/analyses/cfg/indirect_jump_resolvers/jumptable.py

@@ -18,7 +18,12 @@
 from ....exploration_techniques.explorer import Explorer
 from ....utils.constants import DEFAULT_STATEMENT
 from .resolver import IndirectJumpResolver
+from ....misc.ux import once
 
+try:
+    from ....engines import pcode
+except ImportError:
+    pcode = None
 
 l = logging.getLogger(name=__name__)
 
@@ -521,6 +526,10 @@ def __init__(self, project):
         self._find_bss_region()
 
     def filter(self, cfg, addr, func_addr, block, jumpkind):
+        if pcode is not None and isinstance(block.vex, pcode.lifter.IRSB):
+            if once('pcode__indirect_jump_resolver'):
+                l.warning('JumpTableResolver does not support P-Code IR yet; CFG may be incomplete.')
+            return False
 
         if is_arm_arch(self.project.arch):
             # For ARM, we support both jump tables and "call tables" (because of how crazy ARM compilers are...)

angr/engines/__init__.py

@@ -13,3 +13,9 @@
 class UberEngine(SimEngineFailure, SimEngineSyscall, HooksMixin, SimEngineUnicorn, SuperFastpathMixin, TrackActionsMixin, SimInspectMixin, HeavyResilienceMixin, SootMixin, HeavyVEXMixin):
     pass
 
+try:
+	from .pcode import HeavyPcodeMixin
+	class UberEnginePcode(SimEngineFailure, SimEngineSyscall, HooksMixin, HeavyPcodeMixin): # pylint:disable=abstract-method
+		pass
+except ImportError:
+	pass

angr/engines/pcode/__init__.py

@@ -0,0 +1 @@
+from .engine import HeavyPcodeMixin