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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14843 91177308-0d34-0410-b5e6-96231b3b80d8
107 lines
3.5 KiB
C++
107 lines
3.5 KiB
C++
//===- FindUnsafePointerTypes.cpp - Check pointer usage safety ------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines a pass that can be used to determine, interprocedurally,
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// which pointer types are accessed unsafely in a program. If there is an
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// "unsafe" access to a specific pointer type, transformations that depend on
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// type safety cannot be permitted.
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//
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// The result of running this analysis over a program is a set of unsafe pointer
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// types that cannot be transformed. Safe pointer types are not tracked.
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//
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// Additionally, this analysis exports a hidden command line argument that (when
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// enabled) prints out the reasons a type was determined to be unsafe.
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//
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// Currently, the only allowed operations on pointer types are:
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// alloca, malloc, free, getelementptr, load, and store
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/FindUnsafePointerTypes.h"
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#include "llvm/Assembly/CachedWriter.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Module.h"
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#include "llvm/Support/InstIterator.h"
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#include "Support/CommandLine.h"
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using namespace llvm;
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static RegisterAnalysis<FindUnsafePointerTypes>
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X("unsafepointertypes", "Find Unsafe Pointer Types");
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// Provide a command line option to turn on printing of which instructions cause
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// a type to become invalid
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//
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static cl::opt<bool>
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PrintFailures("printunsafeptrinst", cl::Hidden,
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cl::desc("Print Unsafe Pointer Access Instructions"));
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static inline bool isSafeInstruction(const Instruction &I) {
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switch (I.getOpcode()) {
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case Instruction::Alloca:
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case Instruction::Malloc:
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case Instruction::Free:
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case Instruction::Load:
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case Instruction::Store:
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case Instruction::GetElementPtr:
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case Instruction::Call:
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case Instruction::Invoke:
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case Instruction::PHI:
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return true;
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}
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return false;
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}
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bool FindUnsafePointerTypes::run(Module &Mod) {
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for (Module::iterator FI = Mod.begin(), E = Mod.end();
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FI != E; ++FI) {
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const Function *F = FI; // We don't need/want write access
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for (const_inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
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const Type *ITy = I->getType();
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if (isa<PointerType>(ITy) && !UnsafeTypes.count((PointerType*)ITy))
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if (!isSafeInstruction(*I)) {
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UnsafeTypes.insert((PointerType*)ITy);
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if (PrintFailures) {
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CachedWriter CW(F->getParent(), std::cerr);
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std::cerr << "FindUnsafePointerTypes: Type '";
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CW << *ITy;
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std::cerr << "' marked unsafe in '" << F->getName() << "' by:\n";
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CW << *I;
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}
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}
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}
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}
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return false;
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}
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// printResults - Loop over the results of the analysis, printing out unsafe
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// types.
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//
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void FindUnsafePointerTypes::print(std::ostream &o, const Module *M) const {
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if (UnsafeTypes.empty()) {
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o << "SafePointerAccess Analysis: No unsafe types found!\n";
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return;
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}
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CachedWriter CW(M, o);
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o << "SafePointerAccess Analysis: Found these unsafe types:\n";
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unsigned Counter = 1;
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for (std::set<PointerType*>::const_iterator I = getUnsafeTypes().begin(),
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E = getUnsafeTypes().end(); I != E; ++I, ++Counter) {
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o << " #" << Counter << ". ";
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CW << **I << "\n";
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}
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}
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