Rewrite Obj-C workflow in Rust

This is functionally equivalent to the previous workflow_objc, with the
following changes:
1. It mutates the `core.function.metaAnalysis` workflow rather than
   registering a new named workflow. The activities now all check for
   the presence of the Objective-C metadata added by `ObjCProcessor` to
   determine whether they should do work, rather than relying on
   `MachoView` to override the function workflow when Objective-C
   metadata is present. This fixes
   https://github.com/Vector35/binaryninja-api/issues/6779.
2. The auto-inlining of `objc_msgSend` selector stub functions is
   performed in a separate activity from the processing of
   `objc_msgSend` call sites. The selector stub inlining activity is
   configured so that it does not run in `DSCView` as the shared cache
   needs different behavior for stub functions more generally that
   `SharedCacheWorkflow` already provides.
3. The way that types like `id` and `SEL` are referenced is fixed so
   that they show up as `id` rather than `objc_struct*`.

This also replaces the Objective-C portion of the shared cache's
workflow, and incorporates several bug fixes that had been applied to it
but not the standalone Objective-C workflow.

4 files changed, 11 insertions, 218 deletions

diff --git a/view/macho/machoview.cpp b/view/macho/machoview.cpp
index 1da2bda7..1c65629a 100644
--- a/view/macho/machoview.cpp
+++ b/view/macho/machoview.cpp
@@ -1845,6 +1845,17 @@ bool MachoView::InitializeHeader(MachOHeader& header, bool isMainHeader, uint64_
 	BinaryReader virtualReader(this);
 	virtualReader.SetEndianness(m_endian);
 
+	if (m_file->IsBackedByDatabase(GetTypeName()))
+	{
+		// The `core.function.objectiveC` workflow has been removed in favor of the meta-analysis
+		// workflow. If the file is backed by a database, we need to update any references to the
+		// old workflow to refer to the meta-analysis workflow.
+		Ref<Settings> analysisSettings = Settings::Instance();
+		auto workflow = analysisSettings->Get<string>("analysis.workflows.functionWorkflow", this);
+		if (workflow == "core.function.objectiveC")
+			analysisSettings->Set("analysis.workflows.functionWorkflow", "core.function.metaAnalysis", this);
+	}
+
 	bool parseObjCStructs = true;
 	bool parseCFStrings = true;
 	if (settings && settings->Contains("loader.macho.processObjectiveC"))
@@ -1861,20 +1872,6 @@ bool MachoView::InitializeHeader(MachOHeader& header, bool isMainHeader, uint64_
 	{
 		objcProcessor = std::make_unique<MachoObjCProcessor>(this);
 	}
-	if (parseObjCStructs)
-	{
-		if (!settings) // Add our defaults
-		{
-			Ref<Settings> programSettings = Settings::Instance();
-			if (programSettings->Contains("corePlugins.workflows.objc"))
-			{
-				if (programSettings->Get<bool>("corePlugins.workflows.objc"))
-				{
-					programSettings->Set("analysis.workflows.functionWorkflow", "core.function.objectiveC", this);
-				}
-			}
-		}
-	}
 
 	// parse thread starts section if available
 	bool rebaseThreadStarts = false;
@@ -4133,14 +4130,6 @@ Ref<Settings> MachoViewType::GetLoadSettingsForData(BinaryView* data)
 			"default" : true,
 			"description" : "Processes Objective-C structures, applying method names and types from encoded metadata"
 			})");
-		Ref<Settings> programSettings = Settings::Instance();
-		if (programSettings->Contains("corePlugins.workflows.objc"))
-		{
-			if (programSettings->Get<bool>("corePlugins.workflows.objc"))
-			{
-				programSettings->Set("analysis.workflows.functionWorkflow", "core.function.objectiveC", viewRef);
-			}
-		}
 	}
 	if (viewRef->GetSectionByName("__cfstring"))
 	{
diff --git a/view/sharedcache/workflow/ObjCActivity.cpp b/view/sharedcache/workflow/ObjCActivity.cpp
deleted file mode 100644
index f3efbccd..00000000
--- a/view/sharedcache/workflow/ObjCActivity.cpp
+++ /dev/null
@@ -1,184 +0,0 @@
-#include "ObjCActivity.h"
-#include "lowlevelilinstruction.h"
-
-// TODO: Consolidate this with the Obj-C workflow at some point https://github.com/Vector35/workflow_objc
-
-using namespace BinaryNinja;
-
-void ObjCActivity::Register(Workflow &workflow)
-{
-    workflow.RegisterActivity(new Activity(R"({
-	  "name": "core.analysis.sharedCache.objc.adjustCallType",
-	  "eligibility": {
-	    "predicates": [
-	      {
-	        "type": "viewType",
-	        "operator": "in",
-	        "value": [
-	          "DSCView"
-	        ]
-	      }
-	    ]
-	  }
-	})", &AdjustCallType));
-	workflow.Insert("core.function.analyzeTailCalls", "core.analysis.sharedCache.objc.adjustCallType");
-}
-
-std::vector<std::string> splitSelector(const std::string& selector) {
-	std::vector<std::string> components;
-	std::istringstream stream(selector);
-	std::string component;
-
-	while (std::getline(stream, component, ':')) {
-		if (!component.empty()) {
-			components.push_back(component);
-		}
-	}
-
-	return components;
-}
-
-std::vector<std::string> generateArgumentNames(const std::vector<std::string>& components) {
-	std::vector<std::string> argumentNames;
-
-	for (const std::string& component : components) {
-		size_t startPos = component.find_last_of(' ');
-		std::string argumentName = (startPos == std::string::npos) ? component : component.substr(startPos + 1);
-		argumentNames.push_back(argumentName);
-	}
-
-	return argumentNames;
-}
-
-void ObjCActivity::AdjustCallType(Ref<AnalysisContext> ctx)
-{
-    const auto func = ctx->GetFunction();
-	const auto arch = func->GetArchitecture();
-	const auto bv = func->GetView();
-	const auto baseAddr = bv->GetStart();
-
-	const auto llil = ctx->GetLowLevelILFunction();
-	if (!llil) {
-		return;
-	}
-	const auto ssa = llil->GetSSAForm();
-	if (!ssa) {
-		return;
-	}
-
-	const auto rewriteIfEligible = [bv, ssa, baseAddr](size_t insnIndex) {
-		auto insn = ssa->GetInstruction(insnIndex);
-		if (insn.operation != LLIL_CALL_SSA && insn.operation != LLIL_TAILCALL_SSA)
-			return;
-
-		enum class MessageSendType {
-			Normal,
-			Super,
-		};
-
-		MessageSendType messageSendType = MessageSendType::Normal;
-		// Filter out calls that aren't to `objc_msgSend`, `objc_msgSendSuper`, or `objc_msgSendSuper2`.
-		auto callExpr = insn.GetDestExpr();
-		if (auto symbol = bv->GetSymbolByAddress(callExpr.GetValue().value))
-		{
-			std::string_view symbolName = symbol->GetRawNameRef();
-			if (symbolName == "_objc_msgSend")
-				messageSendType = MessageSendType::Normal;
-			else if (symbolName == "_objc_msgSendSuper2" || symbolName == "_objc_msgSendSuper")
-				messageSendType = MessageSendType::Super;
-			else
-			 	return;
-		}
-
-		const auto params = insn.GetParameterExprs();
-		// The second parameter passed to the objc_msgSend call is the address of
-		// either the selector reference or the method's name, which in both cases
-		// is dereferenced to retrieve a selector.
-		if (params.size() < 2)
-			return;
-		uint64_t rawSelector = 0;
-		if (params[1].operation == LLIL_REG_SSA)
-		{
-			const auto selectorRegister = params[1].GetSourceSSARegister<LLIL_REG_SSA>();
-			rawSelector = ssa->GetSSARegisterValue(selectorRegister).value;
-		}
-		else if (params[0].operation == LLIL_SEPARATE_PARAM_LIST_SSA)
-		{
-			if (params[0].GetParameterExprs<LLIL_SEPARATE_PARAM_LIST_SSA>().size() == 0)
-				return;
-			const auto selectorRegister = params[0].GetParameterExprs<LLIL_SEPARATE_PARAM_LIST_SSA>()[1].GetSourceSSARegister<LLIL_REG_SSA>();
-			rawSelector = ssa->GetSSARegisterValue(selectorRegister).value;
-		}
-
-		// Skip if we don't have a
-		if (!rawSelector || rawSelector < baseAddr)
-			return;
-
-		std::string selector;
-		if (bv->IsValidOffset(rawSelector)) {
-			BinaryReader reader(bv);
-			reader.Seek(rawSelector);
-			selector = reader.ReadCString(500);
-		} else {
-			// Look for the `sel_` symbols that ObjCProcessor adds to represent selectors
-			// whose backing regions have not yet been loaded into the view.
-			constexpr std::string_view SelectorPrefix = "sel_";
-
-			auto symbol = bv->GetSymbolByAddress(rawSelector);
-			if (!symbol)
-				return;
-
-			std::string_view name = symbol->GetRawNameRef();
-			if (name.find(SelectorPrefix) != 0)
-				return;
-
-			selector = name.substr(SelectorPrefix.length());
-		}
-
-		// -- Do callsite override
-		auto additionalArgumentCount = std::count(selector.begin(), selector.end(), ':');
-
-		auto retType = bv->GetTypeByName({ "id" });
-		if (!retType)
-			retType = Type::PointerType(ssa->GetArchitecture(), Type::VoidType());
-
-		std::vector<FunctionParameter> callTypeParams;
-		auto cc = bv->GetDefaultPlatform()->GetDefaultCallingConvention();
-
-		if (messageSendType == MessageSendType::Normal)
-			callTypeParams.emplace_back("self", retType, true, Variable());
-		else
-		{
-			auto superType = bv->GetTypeByName({ "objc_super" });
-			if (!superType)
-				superType = Type::PointerType(ssa->GetArchitecture(), Type::VoidType());
-			callTypeParams.emplace_back("super", Type::PointerType(ssa->GetArchitecture(), superType), true, Variable());
-		}
-
-		auto selType = bv->GetTypeByName({ "SEL" });
-		if (!selType)
-			selType = Type::PointerType(ssa->GetArchitecture(), Type::IntegerType(1, true));
-		callTypeParams.emplace_back("sel", selType, true, Variable());
-
-		std::vector<std::string> selectorComponents = splitSelector(selector);
-		std::vector<std::string> argumentNames = generateArgumentNames(selectorComponents);
-
-		for (size_t i = 0; i < additionalArgumentCount; i++)
-		{
-			auto argType = Type::IntegerType(bv->GetAddressSize(), true);
-			if (argumentNames.size() > i && !argumentNames[i].empty())
-				callTypeParams.emplace_back(argumentNames[i], argType, true, Variable());
-			else
-				callTypeParams.emplace_back("arg" + std::to_string(i), argType, true, Variable());
-		}
-
-		auto funcType = Type::FunctionType(retType, cc, callTypeParams);
-		ssa->GetFunction()->SetAutoCallTypeAdjustment(ssa->GetFunction()->GetArchitecture(), insn.address, {funcType, BN_DEFAULT_CONFIDENCE});
-		// --
-	};
-
-	for (const auto& block : ssa->GetBasicBlocks())
-		for (size_t i = block->GetStart(), end = block->GetEnd(); i < end; ++i)
-			rewriteIfEligible(i);
-}
-
diff --git a/view/sharedcache/workflow/ObjCActivity.h b/view/sharedcache/workflow/ObjCActivity.h
deleted file mode 100644
index 05a0d1b8..00000000
--- a/view/sharedcache/workflow/ObjCActivity.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#pragma once
-#include "binaryninjaapi.h"
-
-class ObjCActivity
-{
-    static void AdjustCallType(BinaryNinja::Ref<BinaryNinja::AnalysisContext> ctx);
-public:
-    static void Register(BinaryNinja::Workflow& workflow);
-};
\ No newline at end of file
diff --git a/view/sharedcache/workflow/SharedCacheWorkflow.cpp b/view/sharedcache/workflow/SharedCacheWorkflow.cpp
index 3844516f..dcdf6c23 100644
--- a/view/sharedcache/workflow/SharedCacheWorkflow.cpp
+++ b/view/sharedcache/workflow/SharedCacheWorkflow.cpp
@@ -15,8 +15,6 @@
 #include "thread"
 #include <shared_mutex>
 
-#include "ObjCActivity.h"
-
 using namespace BinaryNinja;
 using namespace SharedCacheAPI;
 
@@ -373,7 +371,6 @@ void SharedCacheWorkflow::Register()
 	Ref<Workflow> workflow = Workflow::Get("core.function.metaAnalysis")->Clone("core.function.metaAnalysis");
 
 	// Register and insert activities here.
-	ObjCActivity::Register(*workflow);
 	workflow->RegisterActivity(new Activity(R"({
 	  "name": "core.analysis.sharedCache.analysis",
 	  "eligibility": {