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Executor.cpp
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Executor.cpp
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//===-- Executor.cpp ------------------------------------------------------===//
//
// The KLEE Symbolic Virtual Machine
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "Executor.h"
#include "AddressSpace.h"
#include "Context.h"
#include "CoreStats.h"
#include "ExecutionState.h"
#include "ExternalDispatcher.h"
#include "GetElementPtrTypeIterator.h"
#include "ImpliedValue.h"
#include "Memory.h"
#include "MemoryManager.h"
#include "PTree.h"
#include "Searcher.h"
#include "SeedInfo.h"
#include "SpecialFunctionHandler.h"
#include "StatsTracker.h"
#include "TimingSolver.h"
#include "UserSearcher.h"
#include "klee/ADT/KTest.h"
#include "klee/ADT/RNG.h"
#include "klee/Config/Version.h"
#include "klee/Core/Interpreter.h"
#include "klee/Expr/ArrayExprOptimizer.h"
#include "klee/Expr/Assignment.h"
#include "klee/Expr/Expr.h"
#include "klee/Expr/ExprPPrinter.h"
#include "klee/Expr/ExprSMTLIBPrinter.h"
#include "klee/Expr/ExprUtil.h"
#include "klee/KDAlloc/kdalloc.h"
#include "klee/Module/Cell.h"
#include "klee/Module/InstructionInfoTable.h"
#include "klee/Module/KCallable.h"
#include "klee/Module/KInstruction.h"
#include "klee/Module/KModule.h"
#include "klee/Solver/Common.h"
#include "klee/Solver/SolverCmdLine.h"
#include "klee/Solver/SolverStats.h"
#include "klee/Statistics/TimerStatIncrementer.h"
#include "klee/Support/Casting.h"
#include "klee/Support/ErrorHandling.h"
#include "klee/Support/FileHandling.h"
#include "klee/Support/ModuleUtil.h"
#include "klee/Support/OptionCategories.h"
#include "klee/System/MemoryUsage.h"
#include "klee/System/Time.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Process.h"
#if LLVM_VERSION_CODE >= LLVM_VERSION(10, 0)
#include "llvm/Support/TypeSize.h"
#else
typedef unsigned TypeSize;
#endif
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cerrno>
#include <cstdint>
#include <cstring>
#include <cxxabi.h>
#include <fstream>
#include <iomanip>
#include <iosfwd>
#include <limits>
#include <sstream>
#include <string>
#include <sys/mman.h>
#include <sys/resource.h>
#include <vector>
using namespace llvm;
using namespace klee;
namespace klee {
cl::OptionCategory DebugCat("Debugging options",
"These are debugging options.");
cl::OptionCategory ExtCallsCat("External call policy options",
"These options impact external calls.");
cl::OptionCategory SeedingCat(
"Seeding options",
"These options are related to the use of seeds to start exploration.");
cl::OptionCategory
TerminationCat("State and overall termination options",
"These options control termination of the overall KLEE "
"execution and of individual states.");
cl::OptionCategory TestGenCat("Test generation options",
"These options impact test generation.");
cl::opt<std::string> MaxTime(
"max-time",
cl::desc("Halt execution after the specified duration. "
"Set to 0s to disable (default=0s)"),
cl::init("0s"),
cl::cat(TerminationCat));
} // namespace klee
namespace {
/*** Test generation options ***/
cl::opt<bool> DumpStatesOnHalt(
"dump-states-on-halt",
cl::init(true),
cl::desc("Dump test cases for all active states on exit (default=true)"),
cl::cat(TestGenCat));
cl::opt<bool> OnlyOutputStatesCoveringNew(
"only-output-states-covering-new",
cl::init(false),
cl::desc("Only output test cases covering new code (default=false)"),
cl::cat(TestGenCat));
cl::opt<bool> EmitAllErrors(
"emit-all-errors", cl::init(false),
cl::desc("Generate tests cases for all errors "
"(default=false, i.e. one per (error,instruction) pair)"),
cl::cat(TestGenCat));
/* Constraint solving options */
cl::opt<unsigned> MaxSymArraySize(
"max-sym-array-size",
cl::desc(
"If a symbolic array exceeds this size (in bytes), symbolic addresses "
"into this array are concretized. Set to 0 to disable (default=0)"),
cl::init(0),
cl::cat(SolvingCat));
cl::opt<bool>
SimplifySymIndices("simplify-sym-indices",
cl::init(false),
cl::desc("Simplify symbolic accesses using equalities "
"from other constraints (default=false)"),
cl::cat(SolvingCat));
cl::opt<bool>
EqualitySubstitution("equality-substitution", cl::init(true),
cl::desc("Simplify equality expressions before "
"querying the solver (default=true)"),
cl::cat(SolvingCat));
/*** External call policy options ***/
enum class ExternalCallPolicy {
None, // No external calls allowed
Concrete, // Only external calls with concrete arguments allowed
All, // All external calls allowed
};
cl::opt<ExternalCallPolicy> ExternalCalls(
"external-calls",
cl::desc("Specify the external call policy"),
cl::values(
clEnumValN(
ExternalCallPolicy::None, "none",
"No external function calls are allowed. Note that KLEE always "
"allows some external calls with concrete arguments to go through "
"(in particular printf and puts), regardless of this option."),
clEnumValN(ExternalCallPolicy::Concrete, "concrete",
"Only external function calls with concrete arguments are "
"allowed (default)"),
clEnumValN(ExternalCallPolicy::All, "all",
"All external function calls are allowed. This concretizes "
"any symbolic arguments in calls to external functions.")),
cl::init(ExternalCallPolicy::Concrete),
cl::cat(ExtCallsCat));
cl::opt<bool> SuppressExternalWarnings(
"suppress-external-warnings",
cl::init(false),
cl::desc("Supress warnings about calling external functions."),
cl::cat(ExtCallsCat));
cl::opt<bool> AllExternalWarnings(
"all-external-warnings",
cl::init(false),
cl::desc("Issue a warning everytime an external call is made, "
"as opposed to once per function (default=false)"),
cl::cat(ExtCallsCat));
cl::opt<std::size_t> ExternalPageThreshold(
"kdalloc-external-page-threshold", cl::init(1024),
cl::desc(
"Threshold for garbage collecting pages used by external calls. If "
"there is a significant number of infrequently used pages resident in "
"memory, these will only be cleaned up if the total number of pages "
"used for external calls is above the given threshold (default=1024)."),
cl::cat(ExtCallsCat));
/*** Seeding options ***/
cl::opt<bool> AlwaysOutputSeeds(
"always-output-seeds",
cl::init(true),
cl::desc(
"Dump test cases even if they are driven by seeds only (default=true)"),
cl::cat(SeedingCat));
cl::opt<bool> OnlyReplaySeeds(
"only-replay-seeds",
cl::init(false),
cl::desc("Discard states that do not have a seed (default=false)."),
cl::cat(SeedingCat));
cl::opt<bool> OnlySeed("only-seed",
cl::init(false),
cl::desc("Stop execution after seeding is done without "
"doing regular search (default=false)."),
cl::cat(SeedingCat));
cl::opt<bool>
AllowSeedExtension("allow-seed-extension",
cl::init(false),
cl::desc("Allow extra (unbound) values to become "
"symbolic during seeding (default=false)."),
cl::cat(SeedingCat));
cl::opt<bool> ZeroSeedExtension(
"zero-seed-extension",
cl::init(false),
cl::desc(
"Use zero-filled objects if matching seed not found (default=false)"),
cl::cat(SeedingCat));
cl::opt<bool> AllowSeedTruncation(
"allow-seed-truncation",
cl::init(false),
cl::desc("Allow smaller buffers than in seeds (default=false)."),
cl::cat(SeedingCat));
cl::opt<bool> NamedSeedMatching(
"named-seed-matching",
cl::init(false),
cl::desc("Use names to match symbolic objects to inputs (default=false)."),
cl::cat(SeedingCat));
cl::opt<std::string>
SeedTime("seed-time",
cl::desc("Amount of time to dedicate to seeds, before normal "
"search (default=0s (off))"),
cl::cat(SeedingCat));
/*** Termination criteria options ***/
cl::list<StateTerminationType> ExitOnErrorType(
"exit-on-error-type",
cl::desc("Stop execution after reaching a specified condition (default=false)"),
cl::values(
clEnumValN(StateTerminationType::Abort, "Abort",
"The program crashed (reached abort()/klee_abort())"),
clEnumValN(StateTerminationType::Assert, "Assert",
"An assertion was hit"),
clEnumValN(StateTerminationType::BadVectorAccess, "BadVectorAccess",
"Vector accessed out of bounds"),
clEnumValN(StateTerminationType::Execution, "Execution",
"Trying to execute an unexpected instruction"),
clEnumValN(StateTerminationType::External, "External",
"External objects referenced"),
clEnumValN(StateTerminationType::Free, "Free",
"Freeing invalid memory"),
clEnumValN(StateTerminationType::Model, "Model",
"Memory model limit hit"),
clEnumValN(StateTerminationType::Overflow, "Overflow",
"An overflow occurred"),
clEnumValN(StateTerminationType::Ptr, "Ptr", "Pointer error"),
clEnumValN(StateTerminationType::ReadOnly, "ReadOnly",
"Write to read-only memory"),
clEnumValN(StateTerminationType::ReportError, "ReportError",
"klee_report_error called"),
clEnumValN(StateTerminationType::InvalidBuiltin, "InvalidBuiltin",
"Passing invalid value to compiler builtin"),
clEnumValN(StateTerminationType::ImplicitTruncation, "ImplicitTruncation",
"Implicit conversion from integer of larger bit width to "
"smaller bit width that results in data loss"),
clEnumValN(StateTerminationType::ImplicitConversion, "ImplicitConversion",
"Implicit conversion between integer types that changes the "
"sign of the value"),
clEnumValN(StateTerminationType::UnreachableCall, "UnreachableCall",
"Control flow reached an unreachable program point"),
clEnumValN(StateTerminationType::MissingReturn, "MissingReturn",
"Reaching the end of a value-returning function without "
"returning a value"),
clEnumValN(StateTerminationType::InvalidLoad, "InvalidLoad",
"Load of a value which is not in the range of representable "
"values for that type"),
clEnumValN(StateTerminationType::NullableAttribute, "NullableAttribute",
"Violation of nullable attribute detected"),
clEnumValN(StateTerminationType::User, "User",
"Wrong klee_* functions invocation")),
cl::ZeroOrMore,
cl::cat(TerminationCat));
cl::opt<unsigned long long> MaxInstructions(
"max-instructions",
cl::desc("Stop execution after this many instructions. Set to 0 to disable (default=0)"),
cl::init(0),
cl::cat(TerminationCat));
cl::opt<unsigned>
MaxForks("max-forks",
cl::desc("Only fork this many times. Set to -1 to disable (default=-1)"),
cl::init(~0u),
cl::cat(TerminationCat));
cl::opt<unsigned> MaxDepth(
"max-depth",
cl::desc("Only allow this many symbolic branches. Set to 0 to disable (default=0)"),
cl::init(0),
cl::cat(TerminationCat));
cl::opt<unsigned> MaxMemory("max-memory",
cl::desc("Refuse to fork when above this amount of "
"memory (in MB) (see -max-memory-inhibit) and terminate "
"states when additional 100MB allocated (default=2000)"),
cl::init(2000),
cl::cat(TerminationCat));
cl::opt<bool> MaxMemoryInhibit(
"max-memory-inhibit",
cl::desc(
"Inhibit forking when above memory cap (see -max-memory) (default=true)"),
cl::init(true),
cl::cat(TerminationCat));
cl::opt<unsigned> RuntimeMaxStackFrames(
"max-stack-frames",
cl::desc("Terminate a state after this many stack frames. Set to 0 to "
"disable (default=8192)"),
cl::init(8192),
cl::cat(TerminationCat));
cl::opt<double> MaxStaticForkPct(
"max-static-fork-pct", cl::init(1.),
cl::desc("Maximum percentage spent by an instruction forking out of the "
"forking of all instructions (default=1.0 (always))"),
cl::cat(TerminationCat));
cl::opt<double> MaxStaticSolvePct(
"max-static-solve-pct", cl::init(1.),
cl::desc("Maximum percentage of solving time that can be spent by a single "
"instruction over total solving time for all instructions "
"(default=1.0 (always))"),
cl::cat(TerminationCat));
cl::opt<double> MaxStaticCPForkPct(
"max-static-cpfork-pct", cl::init(1.),
cl::desc("Maximum percentage spent by an instruction of a call path "
"forking out of the forking of all instructions in the call path "
"(default=1.0 (always))"),
cl::cat(TerminationCat));
cl::opt<double> MaxStaticCPSolvePct(
"max-static-cpsolve-pct", cl::init(1.),
cl::desc("Maximum percentage of solving time that can be spent by a single "
"instruction of a call path over total solving time for all "
"instructions (default=1.0 (always))"),
cl::cat(TerminationCat));
cl::opt<unsigned> MaxStaticPctCheckDelay(
"max-static-pct-check-delay",
cl::desc("Number of forks after which the --max-static-*-pct checks are enforced (default=1000)"),
cl::init(1000),
cl::cat(TerminationCat));
cl::opt<std::string> TimerInterval(
"timer-interval",
cl::desc("Minimum interval to check timers. "
"Affects -max-time, -istats-write-interval, -stats-write-interval, and -uncovered-update-interval (default=1s)"),
cl::init("1s"),
cl::cat(TerminationCat));
/*** Debugging options ***/
/// The different query logging solvers that can switched on/off
enum PrintDebugInstructionsType {
STDERR_ALL, ///
STDERR_SRC,
STDERR_COMPACT,
FILE_ALL, ///
FILE_SRC, ///
FILE_COMPACT ///
};
llvm::cl::bits<PrintDebugInstructionsType> DebugPrintInstructions(
"debug-print-instructions",
llvm::cl::desc("Log instructions during execution."),
llvm::cl::values(
clEnumValN(STDERR_ALL, "all:stderr",
"Log all instructions to stderr "
"in format [src, inst_id, "
"llvm_inst]"),
clEnumValN(STDERR_SRC, "src:stderr",
"Log all instructions to stderr in format [src, inst_id]"),
clEnumValN(STDERR_COMPACT, "compact:stderr",
"Log all instructions to stderr in format [inst_id]"),
clEnumValN(FILE_ALL, "all:file",
"Log all instructions to file "
"instructions.txt in format [src, "
"inst_id, llvm_inst]"),
clEnumValN(FILE_SRC, "src:file",
"Log all instructions to file "
"instructions.txt in format [src, "
"inst_id]"),
clEnumValN(FILE_COMPACT, "compact:file",
"Log all instructions to file instructions.txt in format "
"[inst_id]")),
llvm::cl::CommaSeparated,
cl::cat(DebugCat));
#ifdef HAVE_ZLIB_H
cl::opt<bool> DebugCompressInstructions(
"debug-compress-instructions", cl::init(false),
cl::desc(
"Compress the logged instructions in gzip format (default=false)."),
cl::cat(DebugCat));
#endif
cl::opt<bool> DebugCheckForImpliedValues(
"debug-check-for-implied-values", cl::init(false),
cl::desc("Debug the implied value optimization"),
cl::cat(DebugCat));
} // namespace
// XXX hack
extern "C" unsigned dumpStates, dumpPTree;
unsigned dumpStates = 0, dumpPTree = 0;
Executor::Executor(LLVMContext &ctx, const InterpreterOptions &opts,
InterpreterHandler *ih)
: Interpreter(opts), interpreterHandler(ih), searcher(0),
externalDispatcher(new ExternalDispatcher(ctx)), statsTracker(0),
pathWriter(0), symPathWriter(0), specialFunctionHandler(0), timers{time::Span(TimerInterval)},
replayKTest(0), replayPath(0), usingSeeds(0),
atMemoryLimit(false), inhibitForking(false), haltExecution(false),
ivcEnabled(false), debugLogBuffer(debugBufferString) {
const time::Span maxTime{MaxTime};
if (maxTime) timers.add(
std::make_unique<Timer>(maxTime, [&]{
klee_message("HaltTimer invoked");
setHaltExecution(true);
}));
coreSolverTimeout = time::Span{MaxCoreSolverTime};
if (coreSolverTimeout) UseForkedCoreSolver = true;
std::unique_ptr<Solver> coreSolver = klee::createCoreSolver(CoreSolverToUse);
if (!coreSolver) {
klee_error("Failed to create core solver\n");
}
std::unique_ptr<Solver> solver = constructSolverChain(
std::move(coreSolver),
interpreterHandler->getOutputFilename(ALL_QUERIES_SMT2_FILE_NAME),
interpreterHandler->getOutputFilename(SOLVER_QUERIES_SMT2_FILE_NAME),
interpreterHandler->getOutputFilename(ALL_QUERIES_KQUERY_FILE_NAME),
interpreterHandler->getOutputFilename(SOLVER_QUERIES_KQUERY_FILE_NAME));
this->solver = std::make_unique<TimingSolver>(std::move(solver), EqualitySubstitution);
memory = std::make_unique<MemoryManager>(&arrayCache);
initializeSearchOptions();
if (OnlyOutputStatesCoveringNew && !StatsTracker::useIStats())
klee_error("To use --only-output-states-covering-new, you need to enable --output-istats.");
if (DebugPrintInstructions.isSet(FILE_ALL) ||
DebugPrintInstructions.isSet(FILE_COMPACT) ||
DebugPrintInstructions.isSet(FILE_SRC)) {
std::string debug_file_name =
interpreterHandler->getOutputFilename("instructions.txt");
std::string error;
#ifdef HAVE_ZLIB_H
if (!DebugCompressInstructions) {
#endif
debugInstFile = klee_open_output_file(debug_file_name, error);
#ifdef HAVE_ZLIB_H
} else {
debug_file_name.append(".gz");
debugInstFile = klee_open_compressed_output_file(debug_file_name, error);
}
#endif
if (!debugInstFile) {
klee_error("Could not open file %s : %s", debug_file_name.c_str(),
error.c_str());
}
}
}
llvm::Module *
Executor::setModule(std::vector<std::unique_ptr<llvm::Module>> &modules,
const ModuleOptions &opts) {
assert(!kmodule && !modules.empty() &&
"can only register one module"); // XXX gross
kmodule = std::unique_ptr<KModule>(new KModule());
// Preparing the final module happens in multiple stages
// Link with KLEE intrinsics library before running any optimizations
SmallString<128> LibPath(opts.LibraryDir);
llvm::sys::path::append(LibPath,
"libkleeRuntimeIntrinsic" + opts.OptSuffix + ".bca");
std::string error;
if (!klee::loadFile(LibPath.c_str(), modules[0]->getContext(), modules,
error)) {
klee_error("Could not load KLEE intrinsic file %s", LibPath.c_str());
}
// 1.) Link the modules together
while (kmodule->link(modules, opts.EntryPoint)) {
// 2.) Apply different instrumentation
kmodule->instrument(opts);
}
// 3.) Optimise and prepare for KLEE
// Create a list of functions that should be preserved if used
std::vector<const char *> preservedFunctions;
specialFunctionHandler = new SpecialFunctionHandler(*this);
specialFunctionHandler->prepare(preservedFunctions);
preservedFunctions.push_back(opts.EntryPoint.c_str());
// Preserve the free-standing library calls
preservedFunctions.push_back("memset");
preservedFunctions.push_back("memcpy");
preservedFunctions.push_back("memcmp");
preservedFunctions.push_back("memmove");
kmodule->optimiseAndPrepare(opts, preservedFunctions);
kmodule->checkModule();
// 4.) Manifest the module
kmodule->manifest(interpreterHandler, StatsTracker::useStatistics());
specialFunctionHandler->bind();
if (StatsTracker::useStatistics() || userSearcherRequiresMD2U()) {
statsTracker =
new StatsTracker(*this,
interpreterHandler->getOutputFilename("assembly.ll"),
userSearcherRequiresMD2U());
}
// Initialize the context.
DataLayout *TD = kmodule->targetData.get();
Context::initialize(TD->isLittleEndian(),
(Expr::Width)TD->getPointerSizeInBits());
return kmodule->module.get();
}
Executor::~Executor() {
delete externalDispatcher;
delete specialFunctionHandler;
delete statsTracker;
}
/***/
void Executor::initializeGlobalObject(ExecutionState &state, ObjectState *os,
const Constant *c,
unsigned offset) {
const auto targetData = kmodule->targetData.get();
if (const ConstantVector *cp = dyn_cast<ConstantVector>(c)) {
unsigned elementSize =
targetData->getTypeStoreSize(cp->getType()->getElementType());
for (unsigned i=0, e=cp->getNumOperands(); i != e; ++i)
initializeGlobalObject(state, os, cp->getOperand(i),
offset + i*elementSize);
} else if (isa<ConstantAggregateZero>(c)) {
unsigned i, size = targetData->getTypeStoreSize(c->getType());
for (i=0; i<size; i++)
os->write8(offset+i, (uint8_t) 0);
} else if (const ConstantArray *ca = dyn_cast<ConstantArray>(c)) {
unsigned elementSize =
targetData->getTypeStoreSize(ca->getType()->getElementType());
for (unsigned i=0, e=ca->getNumOperands(); i != e; ++i)
initializeGlobalObject(state, os, ca->getOperand(i),
offset + i*elementSize);
} else if (const ConstantStruct *cs = dyn_cast<ConstantStruct>(c)) {
const StructLayout *sl =
targetData->getStructLayout(cast<StructType>(cs->getType()));
for (unsigned i=0, e=cs->getNumOperands(); i != e; ++i)
initializeGlobalObject(state, os, cs->getOperand(i),
offset + sl->getElementOffset(i));
} else if (const ConstantDataSequential *cds =
dyn_cast<ConstantDataSequential>(c)) {
unsigned elementSize =
targetData->getTypeStoreSize(cds->getElementType());
for (unsigned i=0, e=cds->getNumElements(); i != e; ++i)
initializeGlobalObject(state, os, cds->getElementAsConstant(i),
offset + i*elementSize);
} else if (!isa<UndefValue>(c) && !isa<MetadataAsValue>(c)) {
unsigned StoreBits = targetData->getTypeStoreSizeInBits(c->getType());
ref<ConstantExpr> C = evalConstant(c);
// Extend the constant if necessary;
assert(StoreBits >= C->getWidth() && "Invalid store size!");
if (StoreBits > C->getWidth())
C = C->ZExt(StoreBits);
os->write(offset, C);
}
}
MemoryObject * Executor::addExternalObject(ExecutionState &state,
void *addr, unsigned size,
bool isReadOnly) {
auto mo = memory->allocateFixed(reinterpret_cast<std::uint64_t>(addr),
size, nullptr);
ObjectState *os = bindObjectInState(state, mo, false);
for(unsigned i = 0; i < size; i++)
os->write8(i, ((uint8_t*)addr)[i]);
if(isReadOnly)
os->setReadOnly(true);
return mo;
}
extern void *__dso_handle __attribute__ ((__weak__));
void Executor::initializeGlobals(ExecutionState &state) {
// allocate and initialize globals, done in two passes since we may
// need address of a global in order to initialize some other one.
// allocate memory objects for all globals
allocateGlobalObjects(state);
// initialize aliases first, may be needed for global objects
initializeGlobalAliases();
// finally, do the actual initialization
initializeGlobalObjects(state);
}
void Executor::allocateGlobalObjects(ExecutionState &state) {
Module *m = kmodule->module.get();
if (m->getModuleInlineAsm() != "")
klee_warning("executable has module level assembly (ignoring)");
// represent function globals using the address of the actual llvm function
// object. given that we use malloc to allocate memory in states this also
// ensures that we won't conflict. we don't need to allocate a memory object
// since reading/writing via a function pointer is unsupported anyway.
for (Function &f : *m) {
ref<ConstantExpr> addr;
// If the symbol has external weak linkage then it is implicitly
// not defined in this module; if it isn't resolvable then it
// should be null.
if (f.hasExternalWeakLinkage() &&
!externalDispatcher->resolveSymbol(f.getName().str())) {
addr = Expr::createPointer(0);
} else {
// We allocate an object to represent each function,
// its address can be used for function pointers.
// TODO: Check whether the object is accessed?
auto mo = memory->allocate(8, false, true, &state, &f, 8);
addr = Expr::createPointer(mo->address);
legalFunctions.emplace(mo->address, &f);
}
globalAddresses.emplace(&f, addr);
}
#ifndef WINDOWS
int *errno_addr = getErrnoLocation(state);
MemoryObject *errnoObj =
addExternalObject(state, (void *)errno_addr, sizeof *errno_addr, false);
// Copy values from and to program space explicitly
errnoObj->isUserSpecified = true;
#endif
// Disabled, we don't want to promote use of live externals.
#ifdef HAVE_CTYPE_EXTERNALS
#ifndef WINDOWS
#ifndef DARWIN
/* from /usr/include/ctype.h:
These point into arrays of 384, so they can be indexed by any `unsigned
char' value [0,255]; by EOF (-1); or by any `signed char' value
[-128,-1). ISO C requires that the ctype functions work for `unsigned */
const uint16_t **addr = __ctype_b_loc();
addExternalObject(state, const_cast<uint16_t*>(*addr-128),
384 * sizeof **addr, true);
addExternalObject(state, addr, sizeof(*addr), true);
const int32_t **lower_addr = __ctype_tolower_loc();
addExternalObject(state, const_cast<int32_t*>(*lower_addr-128),
384 * sizeof **lower_addr, true);
addExternalObject(state, lower_addr, sizeof(*lower_addr), true);
const int32_t **upper_addr = __ctype_toupper_loc();
addExternalObject(state, const_cast<int32_t*>(*upper_addr-128),
384 * sizeof **upper_addr, true);
addExternalObject(state, upper_addr, sizeof(*upper_addr), true);
#endif
#endif
#endif
for (const GlobalVariable &v : m->globals()) {
std::size_t globalObjectAlignment = getAllocationAlignment(&v);
Type *ty = v.getValueType();
std::uint64_t size = 0;
if (ty->isSized())
size = kmodule->targetData->getTypeStoreSize(ty);
if (v.isDeclaration()) {
// FIXME: We have no general way of handling unknown external
// symbols. If we really cared about making external stuff work
// better we could support user definition, or use the EXE style
// hack where we check the object file information.
if (!ty->isSized()) {
klee_warning("Type for %.*s is not sized",
static_cast<int>(v.getName().size()), v.getName().data());
}
// XXX - DWD - hardcode some things until we decide how to fix.
#ifndef WINDOWS
if (v.getName() == "_ZTVN10__cxxabiv117__class_type_infoE") {
size = 0x2C;
} else if (v.getName() == "_ZTVN10__cxxabiv120__si_class_type_infoE") {
size = 0x2C;
} else if (v.getName() == "_ZTVN10__cxxabiv121__vmi_class_type_infoE") {
size = 0x2C;
}
#endif
if (size == 0) {
klee_warning("Unable to find size for global variable: %.*s (use will "
"result in out of bounds access)",
static_cast<int>(v.getName().size()), v.getName().data());
}
}
MemoryObject *mo = memory->allocate(size, /*isLocal=*/false,
/*isGlobal=*/true, /*state=*/nullptr,
/*allocSite=*/&v,
/*alignment=*/globalObjectAlignment);
if (!mo)
klee_error("out of memory");
globalObjects.emplace(&v, mo);
globalAddresses.emplace(&v, mo->getBaseExpr());
}
}
void Executor::initializeGlobalAlias(const llvm::Constant *c) {
// aliasee may either be a global value or constant expression
const auto *ga = dyn_cast<GlobalAlias>(c);
if (ga) {
if (globalAddresses.count(ga)) {
// already resolved by previous invocation
return;
}
const llvm::Constant *aliasee = ga->getAliasee();
if (const auto *gv = dyn_cast<GlobalValue>(aliasee)) {
// aliasee is global value
auto it = globalAddresses.find(gv);
// uninitialized only if aliasee is another global alias
if (it != globalAddresses.end()) {
globalAddresses.emplace(ga, it->second);
return;
}
}
}
// resolve aliases in all sub-expressions
for (const auto *op : c->operand_values()) {
initializeGlobalAlias(cast<Constant>(op));
}
if (ga) {
// aliasee is constant expression (or global alias)
globalAddresses.emplace(ga, evalConstant(ga->getAliasee()));
}
}
void Executor::initializeGlobalAliases() {
const Module *m = kmodule->module.get();
for (const GlobalAlias &a : m->aliases()) {
initializeGlobalAlias(&a);
}
}
void Executor::initializeGlobalObjects(ExecutionState &state) {
const Module *m = kmodule->module.get();
for (const GlobalVariable &v : m->globals()) {
MemoryObject *mo = globalObjects.find(&v)->second;
ObjectState *os = bindObjectInState(state, mo, false);
if (v.isDeclaration() && mo->size) {
// Program already running -> object already initialized.
// Read concrete value and write it to our copy.
void *addr;
if (v.getName() == "__dso_handle") {
addr = &__dso_handle; // wtf ?
} else {
addr = externalDispatcher->resolveSymbol(v.getName().str());
}
if (!addr) {
klee_error("Unable to load symbol(%.*s) while initializing globals",
static_cast<int>(v.getName().size()), v.getName().data());
}
for (unsigned offset = 0; offset < mo->size; offset++) {
os->write8(offset, static_cast<unsigned char *>(addr)[offset]);
}
} else if (v.hasInitializer()) {
initializeGlobalObject(state, os, v.getInitializer(), 0);
if (v.isConstant()) {
os->setReadOnly(true);
// initialise constant memory that may be used with external calls
state.addressSpace.copyOutConcrete(mo, os);
}
} else {
os->initializeToRandom();
}
}
}
bool Executor::branchingPermitted(const ExecutionState &state) const {
if ((MaxMemoryInhibit && atMemoryLimit) ||
state.forkDisabled ||
inhibitForking ||
(MaxForks!=~0u && stats::forks >= MaxForks)) {
if (MaxMemoryInhibit && atMemoryLimit)
klee_warning_once(0, "skipping fork (memory cap exceeded)");
else if (state.forkDisabled)
klee_warning_once(0, "skipping fork (fork disabled on current path)");
else if (inhibitForking)
klee_warning_once(0, "skipping fork (fork disabled globally)");
else
klee_warning_once(0, "skipping fork (max-forks reached)");
return false;
}
return true;
}
void Executor::branch(ExecutionState &state,
const std::vector<ref<Expr>> &conditions,
std::vector<ExecutionState *> &result,
BranchType reason) {
TimerStatIncrementer timer(stats::forkTime);
unsigned N = conditions.size();
assert(N);
if (!branchingPermitted(state)) {
unsigned next = theRNG.getInt32() % N;
for (unsigned i=0; i<N; ++i) {
if (i == next) {
result.push_back(&state);
} else {
result.push_back(nullptr);
}
}
stats::inhibitedForks += N - 1;
} else {
stats::forks += N-1;
stats::incBranchStat(reason, N-1);
// XXX do proper balance or keep random?
result.push_back(&state);
for (unsigned i=1; i<N; ++i) {
ExecutionState *es = result[theRNG.getInt32() % i];
ExecutionState *ns = es->branch();
addedStates.push_back(ns);
result.push_back(ns);
processTree->attach(es->ptreeNode, ns, es, reason);
}
}
// If necessary redistribute seeds to match conditions, killing
// states if necessary due to OnlyReplaySeeds (inefficient but
// simple).
std::map< ExecutionState*, std::vector<SeedInfo> >::iterator it =
seedMap.find(&state);
if (it != seedMap.end()) {
std::vector<SeedInfo> seeds = it->second;
seedMap.erase(it);
// Assume each seed only satisfies one condition (necessarily true
// when conditions are mutually exclusive and their conjunction is
// a tautology).
for (std::vector<SeedInfo>::iterator siit = seeds.begin(),
siie = seeds.end(); siit != siie; ++siit) {
unsigned i;
for (i=0; i<N; ++i) {
ref<ConstantExpr> res;
bool success = solver->getValue(
state.constraints, siit->assignment.evaluate(conditions[i]), res,
state.queryMetaData);
assert(success && "FIXME: Unhandled solver failure");
(void) success;
if (res->isTrue())
break;
}
// If we didn't find a satisfying condition randomly pick one
// (the seed will be patched).
if (i==N)
i = theRNG.getInt32() % N;
// Extra check in case we're replaying seeds with a max-fork
if (result[i])
seedMap[result[i]].push_back(*siit);
}
if (OnlyReplaySeeds) {
for (unsigned i=0; i<N; ++i) {
if (result[i] && !seedMap.count(result[i])) {
terminateStateEarlyAlgorithm(*result[i], "Unseeded path during replay", StateTerminationType::Replay);
result[i] = nullptr;
}
}
}
}
for (unsigned i=0; i<N; ++i)
if (result[i])
addConstraint(*result[i], conditions[i]);
}
ref<Expr> Executor::maxStaticPctChecks(ExecutionState ¤t,
ref<Expr> condition) {
if (isa<klee::ConstantExpr>(condition))
return condition;
if (MaxStaticForkPct == 1. && MaxStaticSolvePct == 1. &&
MaxStaticCPForkPct == 1. && MaxStaticCPSolvePct == 1.)
return condition;
// These checks are performed only after at least MaxStaticPctCheckDelay forks
// have been performed since execution started
if (stats::forks < MaxStaticPctCheckDelay)
return condition;
StatisticManager &sm = *theStatisticManager;
CallPathNode *cpn = current.stack.back().callPathNode;
bool reached_max_fork_limit =
(MaxStaticForkPct < 1. &&
(sm.getIndexedValue(stats::forks, sm.getIndex()) >
stats::forks * MaxStaticForkPct));
bool reached_max_cp_fork_limit = (MaxStaticCPForkPct < 1. && cpn &&
(cpn->statistics.getValue(stats::forks) >
stats::forks * MaxStaticCPForkPct));
bool reached_max_solver_limit =
(MaxStaticSolvePct < 1 &&
(sm.getIndexedValue(stats::solverTime, sm.getIndex()) >
stats::solverTime * MaxStaticSolvePct));
bool reached_max_cp_solver_limit =
(MaxStaticCPForkPct < 1. && cpn &&
(cpn->statistics.getValue(stats::solverTime) >