CArrayIntrospection/FindStructElements.cc at master · AlisaMaas/CArrayIntrospection · GitHub

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#define DEBUG_TYPE "find-struct-elements"
#include "FindStructElements.hh"
#include "NameCompare.hh"

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#include <llvm/IR/InstVisitor.h>
#pragma GCC diagnostic pop

#include <fstream>
#include <llvm/IR/DerivedTypes.h>
#include <llvm/IR/Module.h>
#include <llvm/Support/CommandLine.h>
#include <llvm/Support/Debug.h>
#include <llvm/Support/raw_os_ostream.h>
#include <sstream>

using namespace llvm;
using namespace std;


namespace {
	struct FindStructsGEPVisitor : public InstVisitor<FindStructsGEPVisitor> {
		StructElementToValueSet &structCollection;
		std::vector<const StructType *> &orderedTypes;
		FindStructsGEPVisitor(StructElementToValueSet &s,vector<const StructType *> &o) : structCollection(s), orderedTypes(o) {}

		void visitGetElementPtrInst(GetElementPtrInst &);
	};
}


void FindStructsGEPVisitor::visitGetElementPtrInst(GetElementPtrInst &gepi)
{
	DEBUG(dbgs() << "Top of visitor\n");
	DEBUG(dbgs() << gepi << "\n");

	const auto element = StructElement::get(gepi);
	if (!element) return;
	structCollection.emplace(*element, make_shared<ValueSet>()).first->second->insert(&gepi);
	if (find(orderedTypes.begin(), orderedTypes.end(), &element->structure) == orderedTypes.end()) {
		orderedTypes.push_back(&element->structure);
	}

}


static const RegisterPass<FindStructElements> registration("find-struct-elements",
							   "Organize GEP instructions referring to struct element accesses by struct element.",
							   true, true);

char FindStructElements::ID;
static llvm::cl::opt<std::string>
testOutputName("test-find-struct-elements",
	       llvm::cl::Optional,
	       llvm::cl::value_desc("filename"),
	       llvm::cl::desc("Filename to write results to for regression tests"));

FindStructElements::FindStructElements()
	: ModulePass(ID) {
}

void FindStructElements::getAnalysisUsage(AnalysisUsage &usage) const {
	// read-only pass never changes anything
	usage.setPreservesAll();
}


bool FindStructElements::runOnModule(Module &module) {
	DEBUG(dbgs() << "Top of runOnModule()\n");

	for (Function &func : module) {
		DEBUG(dbgs() << "Analyzing " << func.getName() << "\n");
		FindStructsGEPVisitor visitor(structElementCollections, orderedTypes);
		for(BasicBlock &visitee :  func) {
			DEBUG(dbgs() << "Visiting a new basic block...\n");
			visitor.visit(visitee);
		}
	}
	if (!testOutputName.empty()) {
		ofstream out(testOutputName);
		llvm::raw_os_ostream sink(out);
		print(sink, &module);
		sink.flush();
		out.close();
	}
	// read-only pass never changes anything
	return false;
}

void FindStructElements::print(raw_ostream &sink, const Module* ) const {
	for (const StructType *structTy : orderedTypes) {
		sink << structTy->getName() << ":\n";
		for (unsigned i = 0; i < structTy->getNumElements(); i++) {
			const StructElement probe { *structTy, i };
			if (structElementCollections.count(probe) > 0)
				sink << "\telement " << i << " accessed\n";
		}

	}
}