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revng-revng/lib/Decompiler/CDecompilerAction.cpp
T
2019-04-11 18:14:23 +02:00

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//
// This file is distributed under the MIT License. See LICENSE.md for details.
//
// LLVM includes
#include <llvm/IR/Constants.h>
#include <llvm/IR/Module.h>
#include <llvm/IR/Type.h>
// clang includes
#include <clang/AST/Expr.h>
#include <clang/AST/Stmt.h>
#include <clang/Basic/SourceLocation.h>
// revng includes
#include <revng/Support/Assert.h>
// local libraries includes
#include "revng-c/RestructureCFGPass/ASTTree.h"
#include "revng-c/RestructureCFGPass/ExprNode.h"
#include "revng-c/RestructureCFGPass/RegionCFGTree.h"
// local includes
#include "ASTBuildAnalysis.h"
#include "CDecompilerBeautify.h"
#include "DecompilationHelpers.h"
#include "FuncDeclCreationAction.h"
#include "GlobalDeclCreationAction.h"
#include "IRASTTypeTranslation.h"
#include "MarkForSerialization.h"
#include "TypeDeclCreationAction.h"
#include "CDecompilerAction.h"
namespace clang {
namespace tooling {
using GlobalsMap = GlobalDeclCreationAction::GlobalsMap;
using FunctionsMap = FuncDeclCreationAction::FunctionsMap;
using TypeDeclMap = TypeDeclCreationAction::TypeDeclMap;
using FieldDeclMap = IRASTTypeTranslation::FieldDeclMap;
static void buildAndAppendSmts(SmallVectorImpl<clang::Stmt *> &Stmts,
ASTNode *N,
clang::ASTContext &ASTCtx,
IR2AST::StmtBuilder &ASTBuilder,
MarkForSerialization::Analysis &Mark);
static clang::CompoundStmt *
buildCompoundScope(ASTNode *N,
clang::ASTContext &ASTCtx,
IR2AST::StmtBuilder &ASTBuilder,
MarkForSerialization::Analysis &Mark,
SmallVector<clang::Stmt *, 32> AdditionalStmts = {}) {
SmallVector<clang::Stmt *, 32> Stmts;
buildAndAppendSmts(Stmts, N, ASTCtx, ASTBuilder, Mark);
// Add additional statement to handle while e dowhile condition computation.
Stmts.append(AdditionalStmts.begin(), AdditionalStmts.end());
return CompoundStmt::Create(ASTCtx, Stmts, {}, {});
}
static clang::Expr *negateExpr(clang::ASTContext &ASTCtx, clang::Expr *E) {
if (isa<clang::BinaryOperator>(E) or isa<clang::ConditionalOperator>(E))
E = new (ASTCtx) ParenExpr({}, {}, E);
using Unary = clang::UnaryOperator;
E = new (ASTCtx) Unary(E,
UnaryOperatorKind::UO_Not,
E->getType(),
VK_RValue,
OK_Ordinary,
{},
false);
return E;
}
static clang::Expr *createCondExpr(ExprNode *E,
clang::ASTContext &ASTCtx,
SmallVectorImpl<clang::Stmt *> &Stmts,
IR2AST::StmtBuilder &ASTBuilder,
MarkForSerialization::Analysis &Mark) {
struct StackElement {
ExprNode *Node;
llvm::SmallVector<clang::Expr *, 2> ResolvedOperands;
};
llvm::SmallVector<StackElement, 4> VisitStack;
clang::Expr *Result = nullptr;
VisitStack.push_back({ nullptr, {} });
VisitStack.push_back({ E, {} });
bool FoundBasicBlock = false;
revng_assert(VisitStack.size() == 2);
while (VisitStack.size() > 1) {
StackElement &Current = VisitStack.back();
switch (Current.Node->getKind()) {
case ExprNode::NodeKind::NK_Atomic: {
AtomicNode *Atomic = cast<AtomicNode>(Current.Node);
llvm::BasicBlock *BB = Atomic->getConditionalBasicBlock();
auto StmtEnd = ASTBuilder.InstrStmts.end();
auto VDeclEnd = ASTBuilder.VarDecls.end();
auto AdditionalStmtsEnd = ASTBuilder.AdditionalStmts.end();
const std::set<llvm::Instruction *> &Serialized = Mark.getToSerialize(BB);
for (llvm::Instruction &Instr : *BB) {
if (Serialized.count(&Instr) == 0)
continue;
auto StmtIt = ASTBuilder.InstrStmts.find(&Instr);
if (StmtIt != StmtEnd and StmtIt->second != nullptr) {
revng_assert(not FoundBasicBlock);
clang::Stmt *EmittedStmt = nullptr;
auto VarDeclIt = ASTBuilder.VarDecls.find(&Instr);
if (VarDeclIt != VDeclEnd) {
clang::VarDecl *VDecl = VarDeclIt->second;
QualType VarType = VDecl->getType();
clang::Expr *LHS = new (ASTCtx)
DeclRefExpr(VDecl, false, VarType, VK_LValue, {});
clang::Expr *RHS = cast<clang::Expr>(StmtIt->second);
if (RHS->getType() != VarType) {
if (isa<clang::BinaryOperator>(RHS))
RHS = new (ASTCtx) ParenExpr({}, {}, RHS);
RHS = createCast(VarType, RHS, ASTCtx);
}
EmittedStmt = new (ASTCtx) clang::BinaryOperator(LHS,
RHS,
BO_Assign,
VarType,
VK_RValue,
OK_Ordinary,
{},
FPOptions());
} else {
EmittedStmt = StmtIt->second;
}
Stmts.push_back(EmittedStmt);
}
auto AdditionalStmtsIt = ASTBuilder.AdditionalStmts.find(&Instr);
if (AdditionalStmtsIt != AdditionalStmtsEnd)
for (clang::Stmt *S : AdditionalStmtsIt->second)
Stmts.push_back(S);
}
FoundBasicBlock = true;
llvm::Instruction *CondTerminator = BB->getTerminator();
llvm::BranchInst *Br = cast<llvm::BranchInst>(CondTerminator);
revng_assert(Br->isConditional());
llvm::Value *CondValue = Br->getCondition();
clang::Expr *CondExpr = ASTBuilder.getExprForValue(CondValue);
VisitStack.pop_back();
VisitStack.back().ResolvedOperands.push_back(CondExpr);
} break;
case ExprNode::NodeKind::NK_Not: {
NotNode *N = cast<NotNode>(Current.Node);
revng_assert(Current.ResolvedOperands.size() <= 1);
if (Current.ResolvedOperands.size() != 1) {
ExprNode *Negated = N->getNegatedNode();
VisitStack.push_back({ Negated, {} });
} else {
clang::Expr *NotExpr = negateExpr(ASTCtx, Current.ResolvedOperands[0]);
VisitStack.pop_back();
VisitStack.back().ResolvedOperands.push_back(NotExpr);
}
} break;
case ExprNode::NodeKind::NK_And:
case ExprNode::NodeKind::NK_Or: {
unsigned NumOperands = Current.ResolvedOperands.size();
revng_assert(NumOperands <= 2);
using ExprPair = std::pair<ExprNode *, ExprNode *>;
BinaryNode *Binary = cast<BinaryNode>(Current.Node);
if (NumOperands != 2) {
ExprPair Childs = Binary->getInternalNodes();
ExprNode *Op = (NumOperands == 0) ? Childs.first : Childs.second;
VisitStack.push_back({ Op, {} });
} else {
BinaryOperatorKind BinOpKind = isa<AndNode>(Binary) ?
clang::BinaryOperatorKind::BO_And :
clang::BinaryOperatorKind::BO_Or;
clang::Expr *LHS = Current.ResolvedOperands[0];
clang::Expr *RHS = Current.ResolvedOperands[1];
clang::Expr *BinExpr = new (ASTCtx)
clang::BinaryOperator(LHS,
RHS,
BinOpKind,
LHS->getType(),
VK_RValue,
OK_Ordinary,
{},
FPOptions());
VisitStack.pop_back();
VisitStack.back().ResolvedOperands.push_back(BinExpr);
}
} break;
default:
revng_abort();
}
}
revng_assert(VisitStack.size() == 1);
revng_assert(VisitStack.back().ResolvedOperands.size() == 1);
return VisitStack.back().ResolvedOperands[0];
}
static void buildAndAppendSmts(SmallVectorImpl<clang::Stmt *> &Stmts,
ASTNode *N,
clang::ASTContext &ASTCtx,
IR2AST::StmtBuilder &ASTBuilder,
MarkForSerialization::Analysis &Mark) {
if (N == nullptr)
return;
switch (N->getKind()) {
case ASTNode::NodeKind::NK_Break:
Stmts.push_back(new (ASTCtx) clang::BreakStmt(SourceLocation{}));
break;
case ASTNode::NodeKind::NK_Continue: {
ContinueNode *Continue = cast<ContinueNode>(N);
// Print the condition computation code of the if statement.
if (Continue->hasComputation()) {
IfNode *ComputationIfNode = Continue->getComputationIfNode();
createCondExpr(ComputationIfNode->getCondExpr(),
ASTCtx,
Stmts,
ASTBuilder,
Mark);
}
Stmts.push_back(new (ASTCtx) clang::ContinueStmt(SourceLocation{}));
break;
}
case ASTNode::NodeKind::NK_Code: {
CodeNode *Code = cast<CodeNode>(N);
llvm::BasicBlock *BB = Code->getOriginalBB();
revng_assert(BB != nullptr);
auto StmtEnd = ASTBuilder.InstrStmts.end();
auto VDeclEnd = ASTBuilder.VarDecls.end();
auto AdditionalStmtsEnd = ASTBuilder.AdditionalStmts.end();
const std::set<llvm::Instruction *> &Serialized = Mark.getToSerialize(BB);
for (llvm::Instruction &Instr : *BB) {
if (Serialized.count(&Instr) == 0)
continue;
auto StmtIt = ASTBuilder.InstrStmts.find(&Instr);
if (StmtIt != StmtEnd) {
clang::Stmt *EmittedStmt = nullptr;
auto VarDeclIt = ASTBuilder.VarDecls.find(&Instr);
if (VarDeclIt != VDeclEnd) {
clang::VarDecl *VDecl = VarDeclIt->second;
QualType VarType = VDecl->getType();
clang::Expr *LHS = new (ASTCtx)
DeclRefExpr(VDecl, false, VarType, VK_LValue, {});
clang::Expr *RHS = cast<clang::Expr>(StmtIt->second);
if (RHS->getType() != VarType) {
if (isa<clang::BinaryOperator>(RHS))
RHS = new (ASTCtx) ParenExpr({}, {}, RHS);
RHS = createCast(VarType, RHS, ASTCtx);
}
EmittedStmt = new (ASTCtx) clang::BinaryOperator(LHS,
RHS,
BO_Assign,
VarType,
VK_RValue,
OK_Ordinary,
{},
FPOptions());
} else {
EmittedStmt = StmtIt->second;
}
Stmts.push_back(EmittedStmt);
}
auto AdditionalStmtsIt = ASTBuilder.AdditionalStmts.find(&Instr);
if (AdditionalStmtsIt != AdditionalStmtsEnd)
for (clang::Stmt *S : AdditionalStmtsIt->second)
Stmts.push_back(S);
}
break;
}
case ASTNode::NodeKind::NK_If: {
IfNode *If = cast<IfNode>(N);
clang::Expr *CondExpr = createCondExpr(If->getCondExpr(),
ASTCtx,
Stmts,
ASTBuilder,
Mark);
revng_assert(CondExpr != nullptr);
clang::Stmt *ThenScope = buildCompoundScope(If->getThen(),
ASTCtx,
ASTBuilder,
Mark);
clang::Stmt *ElseScope = buildCompoundScope(If->getElse(),
ASTCtx,
ASTBuilder,
Mark);
Stmts.push_back(new (ASTCtx) IfStmt(ASTCtx,
{},
false,
nullptr,
nullptr,
CondExpr,
ThenScope,
{},
ElseScope));
break;
}
case ASTNode::NodeKind::NK_Scs: {
ScsNode *LoopBody = cast<ScsNode>(N);
if (LoopBody->isDoWhile()) {
SmallVector<clang::Stmt *, 32> AdditionalStmts;
// This shold retrieve the if which generates the condition of the loop
// by accesing a dedicated field in the ScsNode.
IfNode *LoopCondition = LoopBody->getRelatedCondition();
clang::Expr *CondExpr = createCondExpr(LoopCondition->getCondExpr(),
ASTCtx,
AdditionalStmts,
ASTBuilder,
Mark);
clang::Stmt *Body = buildCompoundScope(LoopBody->getBody(),
ASTCtx,
ASTBuilder,
Mark,
AdditionalStmts);
for (clang::Stmt *S : AdditionalStmts)
Stmts.push_back(S);
Stmts.push_back(new (ASTCtx) DoStmt(Body, CondExpr, {}, {}, {}));
} else if (LoopBody->isWhile()) {
// This shold retrieve the if which generates the condition of the loop
// by accesing a dedicated field in the ScsNode.
IfNode *LoopCondition = LoopBody->getRelatedCondition();
clang::Expr *CondExpr = createCondExpr(LoopCondition->getCondExpr(),
ASTCtx,
Stmts,
ASTBuilder,
Mark);
clang::Stmt *Body = buildCompoundScope(LoopBody->getBody(),
ASTCtx,
ASTBuilder,
Mark,
{});
Stmts.push_back(new (ASTCtx)
WhileStmt(ASTCtx, nullptr, CondExpr, Body, {}));
} else {
// Standard case.
clang::Stmt *Body = buildCompoundScope(LoopBody->getBody(),
ASTCtx,
ASTBuilder,
Mark);
QualType UInt = ASTCtx.UnsignedIntTy;
uint64_t UIntSize = ASTCtx.getTypeSize(UInt);
clang::Expr *TrueCond = IntegerLiteral::Create(ASTCtx,
llvm::APInt(UIntSize, 1),
UInt,
{});
Stmts.push_back(new (ASTCtx)
WhileStmt(ASTCtx, nullptr, TrueCond, Body, {}));
}
break;
}
case ASTNode::NodeKind::NK_List: {
SequenceNode *Seq = cast<SequenceNode>(N);
for (ASTNode *Child : Seq->nodes())
buildAndAppendSmts(Stmts, Child, ASTCtx, ASTBuilder, Mark);
break;
}
case ASTNode::NodeKind::NK_Switch: {
SwitchNode *Switch = cast<SwitchNode>(N);
llvm::Value *CondVal = Switch->getCondition();
clang::Expr *CondExpr = ASTBuilder.getExprForValue(CondVal);
clang::SwitchStmt *SwitchStatement = new (ASTCtx)
SwitchStmt(ASTCtx, nullptr, nullptr, CondExpr);
SmallVector<clang::Stmt *, 8> BodyStmts;
for (auto &Pair : Switch->cases()) {
llvm::ConstantInt *CaseVal = Pair.first;
ASTNode *CaseNode = Pair.second;
clang::Expr *CaseExpr = ASTBuilder.getExprForValue(CaseVal);
clang::CaseStmt *Case = new (ASTCtx)
CaseStmt(CaseExpr, nullptr, {}, {}, {});
clang::Stmt *CaseBody = buildCompoundScope(CaseNode,
ASTCtx,
ASTBuilder,
Mark);
Case->setSubStmt(CaseBody);
BodyStmts.push_back(Case);
BodyStmts.push_back(new (ASTCtx) clang::BreakStmt(SourceLocation{}));
SwitchStatement->addSwitchCase(Case);
}
clang::Stmt *SwitchBody = CompoundStmt::Create(ASTCtx, BodyStmts, {}, {});
SwitchStatement->setBody(SwitchBody);
Stmts.push_back(SwitchStatement);
} break;
case ASTNode::NodeKind::NK_SwitchCheck: {
SwitchCheckNode *Switch = cast<SwitchCheckNode>(N);
clang::VarDecl *StateVarDecl = ASTBuilder.LoopStateVarDecl;
QualType Type = StateVarDecl->getType();
clang::DeclRefExpr *CondExpr = new (ASTCtx)
DeclRefExpr(StateVarDecl, false, Type, VK_LValue, {});
clang::SwitchStmt *SwitchStatement = new (ASTCtx)
SwitchStmt(ASTCtx, nullptr, nullptr, CondExpr);
SmallVector<clang::Stmt *, 8> BodyStmts;
for (auto &Pair : Switch->cases()) {
unsigned CaseConst = Pair.first;
ASTNode *CaseNode = Pair.second;
clang::Expr *CaseExpr = ASTBuilder.getUIntLiteral(CaseConst);
clang::CaseStmt *Case = new (ASTCtx)
CaseStmt(CaseExpr, nullptr, {}, {}, {});
clang::Stmt *CaseBody = buildCompoundScope(CaseNode,
ASTCtx,
ASTBuilder,
Mark);
Case->setSubStmt(CaseBody);
BodyStmts.push_back(Case);
BodyStmts.push_back(new (ASTCtx) clang::BreakStmt(SourceLocation{}));
SwitchStatement->addSwitchCase(Case);
}
clang::Stmt *SwitchBody = CompoundStmt::Create(ASTCtx, BodyStmts, {}, {});
SwitchStatement->setBody(SwitchBody);
Stmts.push_back(SwitchStatement);
} break;
case ASTNode::NodeKind::NK_Set: {
SetNode *Set = cast<SetNode>(N);
clang::VarDecl *StateVarDecl = ASTBuilder.LoopStateVarDecl;
QualType Type = StateVarDecl->getType();
clang::DeclRefExpr *StateVar = new (ASTCtx)
DeclRefExpr(StateVarDecl, false, Type, VK_LValue, {});
unsigned StateValue = Set->getStateVariableValue();
clang::Expr *StateValueUInt = ASTBuilder.getUIntLiteral(StateValue);
QualType UIntType = StateValueUInt->getType();
clang::Stmt *AssignStmt = new (ASTCtx) clang::BinaryOperator(StateVar,
StateValueUInt,
BO_Assign,
UIntType,
VK_RValue,
OK_Ordinary,
{},
FPOptions());
Stmts.push_back(AssignStmt);
} break;
case ASTNode::NodeKind::NK_IfCheck:
default:
revng_abort();
}
}
static void buildFunctionBody(FunctionsMap::value_type &FPair,
ASTTree &CombedAST,
IR2AST::StmtBuilder &ASTBuilder,
MarkForSerialization::Analysis &Mark) {
llvm::Function &F = *FPair.first;
clang::FunctionDecl *FDecl = FPair.second;
ASTContext &ASTCtx = FDecl->getASTContext();
SmallVector<clang::Decl *, 16> LocalVarDecls;
for (auto &DeclPair : ASTBuilder.AllocaDecls)
LocalVarDecls.push_back(DeclPair.second);
for (auto &DeclPair : ASTBuilder.VarDecls)
LocalVarDecls.push_back(DeclPair.second);
LocalVarDecls.push_back(ASTBuilder.LoopStateVarDecl);
SmallVector<clang::Stmt *, 32> BodyStmts;
buildAndAppendSmts(BodyStmts, CombedAST.getRoot(), ASTCtx, ASTBuilder, Mark);
unsigned NumLocalVars = LocalVarDecls.size();
unsigned NumStmtsInBody = BodyStmts.size() + NumLocalVars;
CompoundStmt *Body = CompoundStmt::CreateEmpty(ASTCtx, NumStmtsInBody);
FDecl->setBody(Body);
for (unsigned I = 0; I < NumLocalVars; ++I) {
Decl *VDecl = LocalVarDecls[I];
auto *LocalVarDeclStmt = new (ASTCtx) DeclStmt(DeclGroupRef(VDecl), {}, {});
Body->body_begin()[I] = LocalVarDeclStmt;
}
for (unsigned I = NumLocalVars; I < NumStmtsInBody; ++I)
Body->body_begin()[I] = BodyStmts[I - NumLocalVars];
#if 0
int I = NumLocalVars;
auto End = ASTInfo.InstrStmts.end();
for (llvm::BasicBlock &BB : F) {
SmallVector<clang::Stmt *, 16> BBStmts;
for (llvm::Instruction &Instr : BB) {
auto It = ASTInfo.InstrStmts.find(&Instr);
if (It != End)
BBStmts.push_back(It->second);
}
auto *BBCompoundStmt = CompoundStmt::Create(ASTCtx, BBStmts, {}, {});
Body->body_begin()[I] = new (ASTCtx)
LabelStmt({}, ASTInfo.LabelDecls.at(&BB), BBCompoundStmt);
++I;
}
#endif
}
class Decompiler : public ASTConsumer {
private:
using PHIIncomingMap = SmallMap<llvm::PHINode *, unsigned, 4>;
using BBPHIMap = SmallMap<llvm::BasicBlock *, PHIIncomingMap, 4>;
public:
explicit Decompiler(llvm::Function &F,
RegionCFG &RCFG,
ASTTree &CombedAST,
BBPHIMap &BlockToPHIIncoming,
std::unique_ptr<llvm::raw_ostream> Out) :
TheF(F),
RCFG(RCFG),
CombedAST(CombedAST),
BlockToPHIIncoming(BlockToPHIIncoming),
Out(std::move(Out)) {}
virtual void HandleTranslationUnit(ASTContext &Context) override {
MarkForSerialization::Analysis Mark(TheF, RCFG);
Mark.initialize();
Mark.run();
beautifyAST(TheF, CombedAST, Mark);
using ConsumerPtr = std::unique_ptr<ASTConsumer>;
FunctionsMap FunctionDecls;
GlobalsMap GlobalVarAST;
TypeDeclMap TypeDecls;
FieldDeclMap FieldDecls;
{
// Build declaration of global types
ConsumerPtr TypeDeclCreate = CreateTypeDeclCreator(TheF,
TypeDecls,
FieldDecls);
TypeDeclCreate->HandleTranslationUnit(Context);
// Build declaration of global variables
ConsumerPtr GlobalDecls = CreateGlobalDeclCreator(TheF,
GlobalVarAST,
TypeDecls,
FieldDecls);
GlobalDecls->HandleTranslationUnit(Context);
// Build function declaration
ConsumerPtr FunDecls = CreateFuncDeclCreator(TheF,
FunctionDecls,
TypeDecls,
FieldDecls);
FunDecls->HandleTranslationUnit(Context);
}
revng_assert(not TheF.isDeclaration());
revng_assert(TheF.getName().startswith("bb."));
auto It = FunctionDecls.find(&TheF);
revng_assert(It != FunctionDecls.end());
clang::FunctionDecl *FunctionDecl = It->second;
IR2AST::StmtBuilder ASTBuilder(TheF,
Mark.getToSerialize(),
Context,
*FunctionDecl,
GlobalVarAST,
FunctionDecls,
BlockToPHIIncoming,
TypeDecls,
FieldDecls);
ASTBuilder.createAST();
buildFunctionBody(*It, CombedAST, ASTBuilder, Mark);
ConsumerPtr Printer = CreateASTPrinter(std::move(Out), "");
Printer->HandleTranslationUnit(Context);
}
private:
llvm::Function &TheF;
RegionCFG &RCFG;
ASTTree &CombedAST;
std::unique_ptr<llvm::raw_ostream> Out;
BBPHIMap &BlockToPHIIncoming;
};
std::unique_ptr<ASTConsumer> CDecompilerAction::newASTConsumer() {
return std::make_unique<Decompiler>(F,
RCFG,
CombedAST,
BlockToPHIIncoming,
std::move(O));
}
} // end namespace tooling
} // end namespace clang