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//===-- ExecutionTree.cpp -------------------------------------------------===//
//
// The KLEE Symbolic Virtual Machine
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "ExecutionTree.h"
#include "ExecutionState.h"
#include "klee/Core/Interpreter.h"
#include "klee/Expr/ExprPPrinter.h"
#include "klee/Module/KInstruction.h"
#include "klee/Support/OptionCategories.h"
#include <bitset>
#include <vector>
using namespace klee;
namespace klee {
llvm::cl::OptionCategory
ExecTreeCat("Execution tree related options",
"These options affect the execution tree handling.");
}
namespace {
llvm::cl::opt<bool> CompressExecutionTree(
"compress-exec-tree",
llvm::cl::desc("Remove intermediate nodes in the execution "
"tree whenever possible (default=false)"),
llvm::cl::init(false), llvm::cl::cat(ExecTreeCat));
llvm::cl::opt<bool> WriteExecutionTree(
"write-exec-tree", llvm::cl::init(false),
llvm::cl::desc("Write execution tree into exec_tree.db (default=false)"),
llvm::cl::cat(ExecTreeCat));
} // namespace
// ExecutionTreeNode
ExecutionTreeNode::ExecutionTreeNode(ExecutionTreeNode *parent,
ExecutionState *state) noexcept
: parent{parent}, left{nullptr}, right{nullptr}, state{state} {
state->executionTreeNode = this;
}
// AnnotatedExecutionTreeNode
AnnotatedExecutionTreeNode::AnnotatedExecutionTreeNode(
ExecutionTreeNode *parent, ExecutionState *state) noexcept
: ExecutionTreeNode(parent, state) {
id = nextID++;
}
// NoopExecutionTree
void NoopExecutionTree::dump(llvm::raw_ostream &os) noexcept {
os << "digraph G {\nTreeNotAvailable [shape=box]\n}";
}
// InMemoryExecutionTree
InMemoryExecutionTree::InMemoryExecutionTree(
ExecutionState &initialState) noexcept {
root = ExecutionTreeNodePtr(createNode(nullptr, &initialState));
initialState.executionTreeNode = root.getPointer();
}
ExecutionTreeNode *InMemoryExecutionTree::createNode(ExecutionTreeNode *parent,
ExecutionState *state) {
return new ExecutionTreeNode(parent, state);
}
void InMemoryExecutionTree::attach(ExecutionTreeNode *node,
ExecutionState *leftState,
ExecutionState *rightState,
BranchType reason) noexcept {
assert(node && !node->left.getPointer() && !node->right.getPointer());
assert(node == rightState->executionTreeNode &&
"Attach assumes the right state is the current state");
node->left = ExecutionTreeNodePtr(createNode(node, leftState));
// The current node inherits the tag
uint8_t currentNodeTag = root.getInt();
if (node->parent)
currentNodeTag = node->parent->left.getPointer() == node
? node->parent->left.getInt()
: node->parent->right.getInt();
node->right =
ExecutionTreeNodePtr(createNode(node, rightState), currentNodeTag);
updateBranchingNode(*node, reason);
node->state = nullptr;
}
void InMemoryExecutionTree::remove(ExecutionTreeNode *n) noexcept {
assert(!n->left.getPointer() && !n->right.getPointer());
updateTerminatingNode(*n);
do {
ExecutionTreeNode *p = n->parent;
if (p) {
if (n == p->left.getPointer()) {
p->left = ExecutionTreeNodePtr(nullptr);
} else {
assert(n == p->right.getPointer());
p->right = ExecutionTreeNodePtr(nullptr);
}
}
delete n;
n = p;
} while (n && !n->left.getPointer() && !n->right.getPointer());
if (n && CompressExecutionTree) {
// We are now at a node that has exactly one child; we've just deleted the
// other one. Eliminate the node and connect its child to the parent
// directly (if it's not the root).
ExecutionTreeNodePtr child = n->left.getPointer() ? n->left : n->right;
ExecutionTreeNode *parent = n->parent;
child.getPointer()->parent = parent;
if (!parent) {
// We are at the root
root = child;
} else {
if (n == parent->left.getPointer()) {
parent->left = child;
} else {
assert(n == parent->right.getPointer());
parent->right = child;
}
}
delete n;
}
}
void InMemoryExecutionTree::dump(llvm::raw_ostream &os) noexcept {
std::unique_ptr<ExprPPrinter> pp(ExprPPrinter::create(os));
pp->setNewline("\\l");
os << "digraph G {\n"
<< "\tsize=\"10,7.5\";\n"
<< "\tratio=fill;\n"
<< "\trotate=90;\n"
<< "\tcenter = \"true\";\n"
<< "\tnode [style=\"filled\",width=.1,height=.1,fontname=\"Terminus\"]\n"
<< "\tedge [arrowsize=.3]\n";
std::vector<const ExecutionTreeNode *> stack;
stack.push_back(root.getPointer());
while (!stack.empty()) {
const ExecutionTreeNode *n = stack.back();
stack.pop_back();
os << "\tn" << n << " [shape=diamond";
if (n->state)
os << ",fillcolor=green";
os << "];\n";
if (n->left.getPointer()) {
os << "\tn" << n << " -> n" << n->left.getPointer() << " [label=0b"
<< std::bitset<PtrBitCount>(n->left.getInt()).to_string() << "];\n";
stack.push_back(n->left.getPointer());
}
if (n->right.getPointer()) {
os << "\tn" << n << " -> n" << n->right.getPointer() << " [label=0b"
<< std::bitset<PtrBitCount>(n->right.getInt()).to_string() << "];\n";
stack.push_back(n->right.getPointer());
}
}
os << "}\n";
}
std::uint8_t InMemoryExecutionTree::getNextId() noexcept {
static_assert(PtrBitCount <= 8);
std::uint8_t id = 1 << registeredIds++;
if (registeredIds > PtrBitCount) {
klee_error("ExecutionTree cannot support more than %d RandomPathSearchers",
PtrBitCount);
}
return id;
}
// PersistentExecutionTree
PersistentExecutionTree::PersistentExecutionTree(
ExecutionState &initialState, InterpreterHandler &ih) noexcept
: writer(ih.getOutputFilename("exec_tree.db")) {
root = ExecutionTreeNodePtr(createNode(nullptr, &initialState));
initialState.executionTreeNode = root.getPointer();
}
void PersistentExecutionTree::dump(llvm::raw_ostream &os) noexcept {
writer.batchCommit(true);
InMemoryExecutionTree::dump(os);
}
ExecutionTreeNode *
PersistentExecutionTree::createNode(ExecutionTreeNode *parent,
ExecutionState *state) {
return new AnnotatedExecutionTreeNode(parent, state);
}
void PersistentExecutionTree::setTerminationType(ExecutionState &state,
StateTerminationType type) {
auto *annotatedNode =
llvm::cast<AnnotatedExecutionTreeNode>(state.executionTreeNode);
annotatedNode->kind = type;
}
void PersistentExecutionTree::updateBranchingNode(ExecutionTreeNode &node,
BranchType reason) {
auto *annotatedNode = llvm::cast<AnnotatedExecutionTreeNode>(&node);
const auto &state = *node.state;
const auto prevPC = state.prevPC;
annotatedNode->asmLine =
prevPC && prevPC->info ? prevPC->info->assemblyLine : 0;
annotatedNode->kind = reason;
writer.write(*annotatedNode);
}
void PersistentExecutionTree::updateTerminatingNode(ExecutionTreeNode &node) {
assert(node.state);
auto *annotatedNode = llvm::cast<AnnotatedExecutionTreeNode>(&node);
const auto &state = *node.state;
const auto prevPC = state.prevPC;
annotatedNode->asmLine =
prevPC && prevPC->info ? prevPC->info->assemblyLine : 0;
annotatedNode->stateID = state.getID();
writer.write(*annotatedNode);
}
// Factory
std::unique_ptr<ExecutionTree>
klee::createExecutionTree(ExecutionState &initialState, bool inMemory,
InterpreterHandler &ih) {
if (WriteExecutionTree)
return std::make_unique<PersistentExecutionTree>(initialState, ih);
if (inMemory)
return std::make_unique<InMemoryExecutionTree>(initialState);
return std::make_unique<NoopExecutionTree>();
};
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