-//===- FindUnsafePointerTypes.cpp - Check pointer usage safety ------------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file defines a pass that can be used to determine, interprocedurally,
-// which pointer types are accessed unsafely in a program. If there is an
-// "unsafe" access to a specific pointer type, transformations that depend on
-// type safety cannot be permitted.
-//
-// The result of running this analysis over a program is a set of unsafe pointer
-// types that cannot be transformed. Safe pointer types are not tracked.
-//
-// Additionally, this analysis exports a hidden command line argument that (when
-// enabled) prints out the reasons a type was determined to be unsafe.
-//
-// Currently, the only allowed operations on pointer types are:
-// alloca, malloc, free, getelementptr, load, and store
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Analysis/FindUnsafePointerTypes.h"
-#include "llvm/Assembly/CachedWriter.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Module.h"
-#include "llvm/Support/InstIterator.h"
-#include "llvm/Support/CommandLine.h"
-using namespace llvm;
-
-static RegisterAnalysis<FindUnsafePointerTypes>
-X("unsafepointertypes", "Find Unsafe Pointer Types");
-
-// Provide a command line option to turn on printing of which instructions cause
-// a type to become invalid
-//
-static cl::opt<bool>
-PrintFailures("printunsafeptrinst", cl::Hidden,
- cl::desc("Print Unsafe Pointer Access Instructions"));
-
-static inline bool isSafeInstruction(const Instruction &I) {
- switch (I.getOpcode()) {
- case Instruction::Alloca:
- case Instruction::Malloc:
- case Instruction::Free:
- case Instruction::Load:
- case Instruction::Store:
- case Instruction::GetElementPtr:
- case Instruction::Call:
- case Instruction::Invoke:
- case Instruction::PHI:
- return true;
- }
- return false;
-}
-
-
-bool FindUnsafePointerTypes::runOnModule(Module &Mod) {
- for (Module::iterator FI = Mod.begin(), E = Mod.end();
- FI != E; ++FI) {
- const Function *F = FI; // We don't need/want write access
- for (const_inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
- const Type *ITy = I->getType();
- if (isa<PointerType>(ITy) && !UnsafeTypes.count((PointerType*)ITy))
- if (!isSafeInstruction(*I)) {
- UnsafeTypes.insert((PointerType*)ITy);
-
- if (PrintFailures) {
- CachedWriter CW(F->getParent(), std::cerr);
- std::cerr << "FindUnsafePointerTypes: Type '";
- CW << *ITy;
- std::cerr << "' marked unsafe in '" << F->getName() << "' by:\n";
- CW << *I;
- }
- }
- }
- }
-
- return false;
-}
-
-
-// printResults - Loop over the results of the analysis, printing out unsafe
-// types.
-//
-void FindUnsafePointerTypes::print(std::ostream &o, const Module *M) const {
- if (UnsafeTypes.empty()) {
- o << "SafePointerAccess Analysis: No unsafe types found!\n";
- return;
- }
-
- CachedWriter CW(M, o);
-
- o << "SafePointerAccess Analysis: Found these unsafe types:\n";
- unsigned Counter = 1;
- for (std::set<PointerType*>::const_iterator I = getUnsafeTypes().begin(),
- E = getUnsafeTypes().end(); I != E; ++I, ++Counter) {
-
- o << " #" << Counter << ". ";
- CW << **I << "\n";
- }
-}
-