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https://github.com/c64scene-ar/llvm-6502.git
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221d688a5e
Method::inst_* is now in llvm/Support/InstIterator.h GraphTraits specializations for BasicBlock and Methods are now in llvm/Support/CFG.h git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1746 91177308-0d34-0410-b5e6-96231b3b80d8
110 lines
3.8 KiB
C++
110 lines
3.8 KiB
C++
//===- SafePointerAccess.cpp - Check pointer usage safety -------------------=//
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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/Type.h"
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#include "llvm/Instruction.h"
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#include "llvm/Method.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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AnalysisID FindUnsafePointerTypes::ID(AnalysisID::create<FindUnsafePointerTypes>());
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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::Flag
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PrintFailures("printunsafeptrinst", "Print Unsafe Pointer Access Instructions",
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cl::Hidden, false);
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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::PHINode:
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return true;
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}
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return false;
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}
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// runOnMethod - Inspect the operations that the specified method does on
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// values of various types. If they are deemed to be 'unsafe' note that the
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// type is not safe to transform.
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//
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bool FindUnsafePointerTypes::run(Module *Mod) {
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for (Module::iterator MI = Mod->begin(), ME = Mod->end();
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MI != ME; ++MI) {
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const Method *M = *MI; // We don't need/want write access
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for (const_inst_iterator I = inst_begin(M), E = inst_end(M); I != E; ++I) {
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const Instruction *Inst = *I;
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const Type *ITy = Inst->getType();
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if (ITy->isPointerType() && !UnsafeTypes.count((PointerType*)ITy))
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if (!isSafeInstruction(Inst)) {
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UnsafeTypes.insert((PointerType*)ITy);
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if (PrintFailures) {
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CachedWriter CW(M->getParent(), std::cerr);
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CW << "FindUnsafePointerTypes: Type '" << ITy
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<< "' marked unsafe in '" << M->getName() << "' by:\n" << Inst;
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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::printResults(const Module *M,
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std::ostream &o) 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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CW << "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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CW << " #" << Counter << ". " << (Value*)*I << "\n";
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}
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}
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// getAnalysisUsageInfo - Of course, we provide ourself...
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//
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void FindUnsafePointerTypes::getAnalysisUsageInfo(Pass::AnalysisSet &Required,
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Pass::AnalysisSet &Destroyed,
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Pass::AnalysisSet &Provided) {
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Provided.push_back(FindUnsafePointerTypes::ID);
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}
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