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gerrit-public.fairphone.software / platform / external / clang / 01a41140cd8ec9475ed0c33384310fbdd3b6de11 / . / lib / Analysis / CFG.cpp
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//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the CFG and CFGBuilder classes for representing and
// building Control-Flow Graphs (CFGs) from ASTs.
//
//===----------------------------------------------------------------------===//
#include "clang/Analysis/CFG.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/PrettyPrinter.h"
#include "clang/AST/StmtVisitor.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/SaveAndRestore.h"
using namespace clang;
namespace {
static SourceLocation GetEndLoc(Decl *D) {
if (VarDecl *VD = dyn_cast<VarDecl>(D))
if (Expr *Ex = VD->getInit())
return Ex->getSourceRange().getEnd();
return D->getLocation();
}
class CFGBuilder;
/// The CFG builder uses a recursive algorithm to build the CFG. When
/// we process an expression, sometimes we know that we must add the
/// subexpressions as block-level expressions. For example:
///
/// exp1 || exp2
///
/// When processing the '||' expression, we know that exp1 and exp2
/// need to be added as block-level expressions, even though they
/// might not normally need to be. AddStmtChoice records this
/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then
/// the builder has an option not to add a subexpression as a
/// block-level expression.
///
class AddStmtChoice {
public:
enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 };
AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {}
bool alwaysAdd(CFGBuilder &builder,
const Stmt *stmt) const;
/// Return a copy of this object, except with the 'always-add' bit
/// set as specified.
AddStmtChoice withAlwaysAdd(bool alwaysAdd) const {
return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd);
}
private:
Kind kind;
};
/// LocalScope - Node in tree of local scopes created for C++ implicit
/// destructor calls generation. It contains list of automatic variables
/// declared in the scope and link to position in previous scope this scope
/// began in.
///
/// The process of creating local scopes is as follows:
/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null),
/// - Before processing statements in scope (e.g. CompoundStmt) create
/// LocalScope object using CFGBuilder::ScopePos as link to previous scope
/// and set CFGBuilder::ScopePos to the end of new scope,
/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points
/// at this VarDecl,
/// - For every normal (without jump) end of scope add to CFGBlock destructors
/// for objects in the current scope,
/// - For every jump add to CFGBlock destructors for objects
/// between CFGBuilder::ScopePos and local scope position saved for jump
/// target. Thanks to C++ restrictions on goto jumps we can be sure that
/// jump target position will be on the path to root from CFGBuilder::ScopePos
/// (adding any variable that doesn't need constructor to be called to
/// LocalScope can break this assumption),
///
class LocalScope {
public:
typedef BumpVector<VarDecl*> AutomaticVarsTy;
/// const_iterator - Iterates local scope backwards and jumps to previous
/// scope on reaching the beginning of currently iterated scope.
class const_iterator {
const LocalScope* Scope;
/// VarIter is guaranteed to be greater then 0 for every valid iterator.
/// Invalid iterator (with null Scope) has VarIter equal to 0.
unsigned VarIter;
public:
/// Create invalid iterator. Dereferencing invalid iterator is not allowed.
/// Incrementing invalid iterator is allowed and will result in invalid
/// iterator.
const_iterator()
: Scope(NULL), VarIter(0) {}
/// Create valid iterator. In case when S.Prev is an invalid iterator and
/// I is equal to 0, this will create invalid iterator.
const_iterator(const LocalScope& S, unsigned I)
: Scope(&S), VarIter(I) {
// Iterator to "end" of scope is not allowed. Handle it by going up
// in scopes tree possibly up to invalid iterator in the root.
if (VarIter == 0 && Scope)
*this = Scope->Prev;
}
VarDecl *const* operator->() const {
assert (Scope && "Dereferencing invalid iterator is not allowed");
assert (VarIter != 0 && "Iterator has invalid value of VarIter member");
return &Scope->Vars[VarIter - 1];
}
VarDecl *operator*() const {
return *this->operator->();
}
const_iterator &operator++() {
if (!Scope)
return *this;
assert (VarIter != 0 && "Iterator has invalid value of VarIter member");
--VarIter;
if (VarIter == 0)
*this = Scope->Prev;
return *this;
}
const_iterator operator++(int) {
const_iterator P = *this;
++*this;
return P;
}
bool operator==(const const_iterator &rhs) const {
return Scope == rhs.Scope && VarIter == rhs.VarIter;
}
bool operator!=(const const_iterator &rhs) const {
return !(*this == rhs);
}
operator bool() const {
return *this != const_iterator();
}
int distance(const_iterator L);
};
friend class const_iterator;
private:
BumpVectorContext ctx;
/// Automatic variables in order of declaration.
AutomaticVarsTy Vars;
/// Iterator to variable in previous scope that was declared just before
/// begin of this scope.
const_iterator Prev;
public:
/// Constructs empty scope linked to previous scope in specified place.
LocalScope(BumpVectorContext &ctx, const_iterator P)
: ctx(ctx), Vars(ctx, 4), Prev(P) {}
/// Begin of scope in direction of CFG building (backwards).
const_iterator begin() const { return const_iterator(*this, Vars.size()); }
void addVar(VarDecl *VD) {
Vars.push_back(VD, ctx);
}
};
/// distance - Calculates distance from this to L. L must be reachable from this
/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t.
/// number of scopes between this and L.
int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
int D = 0;
const_iterator F = *this;
while (F.Scope != L.Scope) {
assert (F != const_iterator()
&& "L iterator is not reachable from F iterator.");
D += F.VarIter;
F = F.Scope->Prev;
}
D += F.VarIter - L.VarIter;
return D;
}
/// BlockScopePosPair - Structure for specifying position in CFG during its
/// build process. It consists of CFGBlock that specifies position in CFG graph
/// and LocalScope::const_iterator that specifies position in LocalScope graph.
struct BlockScopePosPair {
BlockScopePosPair() : block(0) {}
BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos)
: block(b), scopePosition(scopePos) {}
CFGBlock *block;
LocalScope::const_iterator scopePosition;
};
/// TryResult - a class representing a variant over the values
/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool,
/// and is used by the CFGBuilder to decide if a branch condition
/// can be decided up front during CFG construction.
class TryResult {
int X;
public:
TryResult(bool b) : X(b ? 1 : 0) {}
TryResult() : X(-1) {}
bool isTrue() const { return X == 1; }
bool isFalse() const { return X == 0; }
bool isKnown() const { return X >= 0; }
void negate() {
assert(isKnown());
X ^= 0x1;
}
};
/// CFGBuilder - This class implements CFG construction from an AST.
/// The builder is stateful: an instance of the builder should be used to only
/// construct a single CFG.
///
/// Example usage:
///
/// CFGBuilder builder;
/// CFG* cfg = builder.BuildAST(stmt1);
///
/// CFG construction is done via a recursive walk of an AST. We actually parse
/// the AST in reverse order so that the successor of a basic block is
/// constructed prior to its predecessor. This allows us to nicely capture
/// implicit fall-throughs without extra basic blocks.
///
class CFGBuilder {
typedef BlockScopePosPair JumpTarget;
typedef BlockScopePosPair JumpSource;
ASTContext *Context;
OwningPtr<CFG> cfg;
CFGBlock *Block;
CFGBlock *Succ;
JumpTarget ContinueJumpTarget;
JumpTarget BreakJumpTarget;
CFGBlock *SwitchTerminatedBlock;
CFGBlock *DefaultCaseBlock;
CFGBlock *TryTerminatedBlock;
// Current position in local scope.
LocalScope::const_iterator ScopePos;
// LabelMap records the mapping from Label expressions to their jump targets.
typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy;
LabelMapTy LabelMap;
// A list of blocks that end with a "goto" that must be backpatched to their
// resolved targets upon completion of CFG construction.
typedef std::vector<JumpSource> BackpatchBlocksTy;
BackpatchBlocksTy BackpatchBlocks;
// A list of labels whose address has been taken (for indirect gotos).
typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy;
LabelSetTy AddressTakenLabels;
bool badCFG;
const CFG::BuildOptions &BuildOpts;
// State to track for building switch statements.
bool switchExclusivelyCovered;
Expr::EvalResult *switchCond;
CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry;
const Stmt *lastLookup;
// Caches boolean evaluations of expressions to avoid multiple re-evaluations
// during construction of branches for chained logical operators.
typedef llvm::DenseMap<Expr *, TryResult> CachedBoolEvalsTy;
CachedBoolEvalsTy CachedBoolEvals;
public:
explicit CFGBuilder(ASTContext *astContext,
const CFG::BuildOptions &buildOpts)
: Context(astContext), cfg(new CFG()), // crew a new CFG
Block(NULL), Succ(NULL),
SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL),
TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts),
switchExclusivelyCovered(false), switchCond(0),
cachedEntry(0), lastLookup(0) {}
// buildCFG - Used by external clients to construct the CFG.
CFG* buildCFG(const Decl *D, Stmt *Statement);
bool alwaysAdd(const Stmt *stmt);
private:
// Visitors to walk an AST and construct the CFG.
CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
CFGBlock *VisitBreakStmt(BreakStmt *B);
CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
CFGBlock *VisitCaseStmt(CaseStmt *C);
CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
CFGBlock *VisitCompoundStmt(CompoundStmt *C);
CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
AddStmtChoice asc);
CFGBlock *VisitContinueStmt(ContinueStmt *C);
CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
AddStmtChoice asc);
CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
AddStmtChoice asc);
CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
AddStmtChoice asc);
CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
CFGBlock *VisitDeclStmt(DeclStmt *DS);
CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
CFGBlock *VisitDefaultStmt(DefaultStmt *D);
CFGBlock *VisitDoStmt(DoStmt *D);
CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc);
CFGBlock *VisitForStmt(ForStmt *F);
CFGBlock *VisitGotoStmt(GotoStmt *G);
CFGBlock *VisitIfStmt(IfStmt *I);
CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
CFGBlock *VisitLabelStmt(LabelStmt *L);
CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
CFGBlock *VisitLogicalOperator(BinaryOperator *B);
std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
Stmt *Term,
CFGBlock *TrueBlock,
CFGBlock *FalseBlock);
CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
CFGBlock *VisitReturnStmt(ReturnStmt *R);
CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
CFGBlock *VisitSwitchStmt(SwitchStmt *S);
CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
AddStmtChoice asc);
CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
CFGBlock *VisitWhileStmt(WhileStmt *W);
CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
CFGBlock *VisitChildren(Stmt *S);
CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
// Visitors to walk an AST and generate destructors of temporaries in
// full expression.
CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false);
CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E);
CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E);
CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E,
bool BindToTemporary);
CFGBlock *
VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E,
bool BindToTemporary);
// NYS == Not Yet Supported
CFGBlock *NYS() {
badCFG = true;
return Block;
}
void autoCreateBlock() { if (!Block) Block = createBlock(); }
CFGBlock *createBlock(bool add_successor = true);
CFGBlock *createNoReturnBlock();
CFGBlock *addStmt(Stmt *S) {
return Visit(S, AddStmtChoice::AlwaysAdd);
}
CFGBlock *addInitializer(CXXCtorInitializer *I);
void addAutomaticObjDtors(LocalScope::const_iterator B,
LocalScope::const_iterator E, Stmt *S);
void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
// Local scopes creation.
LocalScope* createOrReuseLocalScope(LocalScope* Scope);
void addLocalScopeForStmt(Stmt *S);
LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL);
LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL);
void addLocalScopeAndDtors(Stmt *S);
// Interface to CFGBlock - adding CFGElements.
void appendStmt(CFGBlock *B, const Stmt *S) {
if (alwaysAdd(S) && cachedEntry)
cachedEntry->second = B;
// All block-level expressions should have already been IgnoreParens()ed.
assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
}
void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
B->appendInitializer(I, cfg->getBumpVectorContext());
}
void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
B->appendBaseDtor(BS, cfg->getBumpVectorContext());
}
void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
B->appendMemberDtor(FD, cfg->getBumpVectorContext());
}
void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
}
void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
}
void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
LocalScope::const_iterator B, LocalScope::const_iterator E);
void addSuccessor(CFGBlock *B, CFGBlock *S) {
B->addSuccessor(S, cfg->getBumpVectorContext());
}
/// Try and evaluate an expression to an integer constant.
bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
if (!BuildOpts.PruneTriviallyFalseEdges)
return false;
return !S->isTypeDependent() &&
!S->isValueDependent() &&
S->EvaluateAsRValue(outResult, *Context);
}
/// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
/// if we can evaluate to a known value, otherwise return -1.
TryResult tryEvaluateBool(Expr *S) {
if (!BuildOpts.PruneTriviallyFalseEdges ||
S->isTypeDependent() || S->isValueDependent())
return TryResult();
if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
if (Bop->isLogicalOp()) {
// Check the cache first.
CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
if (I != CachedBoolEvals.end())
return I->second; // already in map;
// Retrieve result at first, or the map might be updated.
TryResult Result = evaluateAsBooleanConditionNoCache(S);
CachedBoolEvals[S] = Result; // update or insert
return Result;
}
else {
switch (Bop->getOpcode()) {
default: break;
// For 'x & 0' and 'x * 0', we can determine that
// the value is always false.
case BO_Mul:
case BO_And: {
// If either operand is zero, we know the value
// must be false.
llvm::APSInt IntVal;
if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) {
if (IntVal.getBoolValue() == false) {
return TryResult(false);
}
}
if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) {
if (IntVal.getBoolValue() == false) {
return TryResult(false);
}
}
}
break;
}
}
}
return evaluateAsBooleanConditionNoCache(S);
}
/// \brief Evaluate as boolean \param E without using the cache.
TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
if (Bop->isLogicalOp()) {
TryResult LHS = tryEvaluateBool(Bop->getLHS());
if (LHS.isKnown()) {
// We were able to evaluate the LHS, see if we can get away with not
// evaluating the RHS: 0 && X -> 0, 1 || X -> 1
if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
return LHS.isTrue();
TryResult RHS = tryEvaluateBool(Bop->getRHS());
if (RHS.isKnown()) {
if (Bop->getOpcode() == BO_LOr)
return LHS.isTrue() || RHS.isTrue();
else
return LHS.isTrue() && RHS.isTrue();
}
} else {
TryResult RHS = tryEvaluateBool(Bop->getRHS());
if (RHS.isKnown()) {
// We can't evaluate the LHS; however, sometimes the result
// is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
return RHS.isTrue();
}
}
return TryResult();
}
}
bool Result;
if (E->EvaluateAsBooleanCondition(Result, *Context))
return Result;
return TryResult();
}
};
inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
const Stmt *stmt) const {
return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
}
bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
bool shouldAdd = BuildOpts.alwaysAdd(stmt);
if (!BuildOpts.forcedBlkExprs)
return shouldAdd;
if (lastLookup == stmt) {
if (cachedEntry) {
assert(cachedEntry->first == stmt);
return true;
}
return shouldAdd;
}
lastLookup = stmt;
// Perform the lookup!
CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
if (!fb) {
// No need to update 'cachedEntry', since it will always be null.
assert(cachedEntry == 0);
return shouldAdd;
}
CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
if (itr == fb->end()) {
cachedEntry = 0;
return shouldAdd;
}
cachedEntry = &*itr;
return true;
}
// FIXME: Add support for dependent-sized array types in C++?
// Does it even make sense to build a CFG for an uninstantiated template?
static const VariableArrayType *FindVA(const Type *t) {
while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
if (vat->getSizeExpr())
return vat;
t = vt->getElementType().getTypePtr();
}
return 0;
}
/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
/// arbitrary statement. Examples include a single expression or a function
/// body (compound statement). The ownership of the returned CFG is
/// transferred to the caller. If CFG construction fails, this method returns
/// NULL.
CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
assert(cfg.get());
if (!Statement)
return NULL;
// Create an empty block that will serve as the exit block for the CFG. Since
// this is the first block added to the CFG, it will be implicitly registered
// as the exit block.
Succ = createBlock();
assert(Succ == &cfg->getExit());
Block = NULL; // the EXIT block is empty. Create all other blocks lazily.
if (BuildOpts.AddImplicitDtors)
if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
addImplicitDtorsForDestructor(DD);
// Visit the statements and create the CFG.
CFGBlock *B = addStmt(Statement);
if (badCFG)
return NULL;
// For C++ constructor add initializers to CFG.
if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(),
E = CD->init_rend(); I != E; ++I) {
B = addInitializer(*I);
if (badCFG)
return NULL;
}
}
if (B)
Succ = B;
// Backpatch the gotos whose label -> block mappings we didn't know when we
// encountered them.
for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
E = BackpatchBlocks.end(); I != E; ++I ) {
CFGBlock *B = I->block;
GotoStmt *G = cast<GotoStmt>(B->getTerminator());
LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
// If there is no target for the goto, then we are looking at an
// incomplete AST. Handle this by not registering a successor.
if (LI == LabelMap.end()) continue;
JumpTarget JT = LI->second;
prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
JT.scopePosition);
addSuccessor(B, JT.block);
}
// Add successors to the Indirect Goto Dispatch block (if we have one).
if (CFGBlock *B = cfg->getIndirectGotoBlock())
for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
E = AddressTakenLabels.end(); I != E; ++I ) {
// Lookup the target block.
LabelMapTy::iterator LI = LabelMap.find(*I);
// If there is no target block that contains label, then we are looking
// at an incomplete AST. Handle this by not registering a successor.
if (LI == LabelMap.end()) continue;
addSuccessor(B, LI->second.block);
}
// Create an empty entry block that has no predecessors.
cfg->setEntry(createBlock());
return cfg.take();
}
/// createBlock - Used to lazily create blocks that are connected
/// to the current (global) succcessor.
CFGBlock *CFGBuilder::createBlock(bool add_successor) {
CFGBlock *B = cfg->createBlock();
if (add_successor && Succ)
addSuccessor(B, Succ);
return B;
}
/// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
/// CFG. It is *not* connected to the current (global) successor, and instead
/// directly tied to the exit block in order to be reachable.
CFGBlock *CFGBuilder::createNoReturnBlock() {
CFGBlock *B = createBlock(false);
B->setHasNoReturnElement();
addSuccessor(B, &cfg->getExit());
return B;
}
/// addInitializer - Add C++ base or member initializer element to CFG.
CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
if (!BuildOpts.AddInitializers)
return Block;
bool IsReference = false;
bool HasTemporaries = false;
// Destructors of temporaries in initialization expression should be called
// after initialization finishes.
Expr *Init = I->getInit();
if (Init) {
if (FieldDecl *FD = I->getAnyMember())
IsReference = FD->getType()->isReferenceType();
HasTemporaries = isa<ExprWithCleanups>(Init);
if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
// Generate destructors for temporaries in initialization expression.
VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
IsReference);
}
}
autoCreateBlock();
appendInitializer(Block, I);
if (Init) {
if (HasTemporaries) {
// For expression with temporaries go directly to subexpression to omit
// generating destructors for the second time.
return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
}
return Visit(Init);
}
return Block;
}
/// \brief Retrieve the type of the temporary object whose lifetime was
/// extended by a local reference with the given initializer.
static QualType getReferenceInitTemporaryType(ASTContext &Context,
const Expr *Init) {
while (true) {
// Skip parentheses.
Init = Init->IgnoreParens();
// Skip through cleanups.
if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
Init = EWC->getSubExpr();
continue;
}
// Skip through the temporary-materialization expression.
if (const MaterializeTemporaryExpr *MTE
= dyn_cast<MaterializeTemporaryExpr>(Init)) {
Init = MTE->GetTemporaryExpr();
continue;
}
// Skip derived-to-base and no-op casts.
if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) {
if ((CE->getCastKind() == CK_DerivedToBase ||
CE->getCastKind() == CK_UncheckedDerivedToBase ||
CE->getCastKind() == CK_NoOp) &&
Init->getType()->isRecordType()) {
Init = CE->getSubExpr();
continue;
}
}
// Skip member accesses into rvalues.
if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) {
if (!ME->isArrow() && ME->getBase()->isRValue()) {
Init = ME->getBase();
continue;
}
}
break;
}
return Init->getType();
}
/// addAutomaticObjDtors - Add to current block automatic objects destructors
/// for objects in range of local scope positions. Use S as trigger statement
/// for destructors.
void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
LocalScope::const_iterator E, Stmt *S) {
if (!BuildOpts.AddImplicitDtors)
return;
if (B == E)
return;
// We need to append the destructors in reverse order, but any one of them
// may be a no-return destructor which changes the CFG. As a result, buffer
// this sequence up and replay them in reverse order when appending onto the
// CFGBlock(s).
SmallVector<VarDecl*, 10> Decls;
Decls.reserve(B.distance(E));
for (LocalScope::const_iterator I = B; I != E; ++I)
Decls.push_back(*I);
for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
E = Decls.rend();
I != E; ++I) {
// If this destructor is marked as a no-return destructor, we need to
// create a new block for the destructor which does not have as a successor
// anything built thus far: control won't flow out of this block.
QualType Ty = (*I)->getType();
if (Ty->isReferenceType()) {
Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit());
}
Ty = Context->getBaseElementType(Ty);
const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor();
if (Dtor->isNoReturn())
Block = createNoReturnBlock();
else
autoCreateBlock();
appendAutomaticObjDtor(Block, *I, S);
}
}
/// addImplicitDtorsForDestructor - Add implicit destructors generated for
/// base and member objects in destructor.
void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
assert (BuildOpts.AddImplicitDtors
&& "Can be called only when dtors should be added");
const CXXRecordDecl *RD = DD->getParent();
// At the end destroy virtual base objects.
for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(),
VE = RD->vbases_end(); VI != VE; ++VI) {
const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl();
if (!CD->hasTrivialDestructor()) {
autoCreateBlock();
appendBaseDtor(Block, VI);
}
}
// Before virtual bases destroy direct base objects.
for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(),
BE = RD->bases_end(); BI != BE; ++BI) {
if (!BI->isVirtual()) {
const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl();
if (!CD->hasTrivialDestructor()) {
autoCreateBlock();
appendBaseDtor(Block, BI);
}
}
}
// First destroy member objects.
for (CXXRecordDecl::field_iterator FI = RD->field_begin(),
FE = RD->field_end(); FI != FE; ++FI) {
// Check for constant size array. Set type to array element type.
QualType QT = FI->getType();
if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
if (AT->getSize() == 0)
continue;
QT = AT->getElementType();
}
if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
if (!CD->hasTrivialDestructor()) {
autoCreateBlock();
appendMemberDtor(Block, *FI);
}
}
}
/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
/// way return valid LocalScope object.
LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
if (!Scope) {
llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
Scope = alloc.Allocate<LocalScope>();
BumpVectorContext ctx(alloc);
new (Scope) LocalScope(ctx, ScopePos);
}
return Scope;
}
/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
/// that should create implicit scope (e.g. if/else substatements).
void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
if (!BuildOpts.AddImplicitDtors)
return;
LocalScope *Scope = 0;
// For compound statement we will be creating explicit scope.
if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end()
; BI != BE; ++BI) {
Stmt *SI = (*BI)->stripLabelLikeStatements();
if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
Scope = addLocalScopeForDeclStmt(DS, Scope);
}
return;
}
// For any other statement scope will be implicit and as such will be
// interesting only for DeclStmt.
if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
addLocalScopeForDeclStmt(DS);
}
/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
/// reuse Scope if not NULL.
LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
LocalScope* Scope) {
if (!BuildOpts.AddImplicitDtors)
return Scope;
for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end()
; DI != DE; ++DI) {
if (VarDecl *VD = dyn_cast<VarDecl>(*DI))
Scope = addLocalScopeForVarDecl(VD, Scope);
}
return Scope;
}
/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
/// create add scope for automatic objects and temporary objects bound to
/// const reference. Will reuse Scope if not NULL.
LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
LocalScope* Scope) {
if (!BuildOpts.AddImplicitDtors)
return Scope;
// Check if variable is local.
switch (VD->getStorageClass()) {
case SC_None:
case SC_Auto:
case SC_Register:
break;
default: return Scope;
}
// Check for const references bound to temporary. Set type to pointee.
QualType QT = VD->getType();
if (QT.getTypePtr()->isReferenceType()) {
if (!VD->extendsLifetimeOfTemporary())
return Scope;
QT = getReferenceInitTemporaryType(*Context, VD->getInit());
}
// Check for constant size array. Set type to array element type.
while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
if (AT->getSize() == 0)
return Scope;
QT = AT->getElementType();
}
// Check if type is a C++ class with non-trivial destructor.
if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
if (!CD->hasTrivialDestructor()) {
// Add the variable to scope
Scope = createOrReuseLocalScope(Scope);
Scope->addVar(VD);
ScopePos = Scope->begin();
}
return Scope;
}
/// addLocalScopeAndDtors - For given statement add local scope for it and
/// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
if (!BuildOpts.AddImplicitDtors)
return;
LocalScope::const_iterator scopeBeginPos = ScopePos;
addLocalScopeForStmt(S);
addAutomaticObjDtors(ScopePos, scopeBeginPos, S);
}
/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
/// variables with automatic storage duration to CFGBlock's elements vector.
/// Elements will be prepended to physical beginning of the vector which
/// happens to be logical end. Use blocks terminator as statement that specifies
/// destructors call site.
/// FIXME: This mechanism for adding automatic destructors doesn't handle
/// no-return destructors properly.
void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
LocalScope::const_iterator B, LocalScope::const_iterator E) {
BumpVectorContext &C = cfg->getBumpVectorContext();
CFGBlock::iterator InsertPos
= Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
for (LocalScope::const_iterator I = B; I != E; ++I)
InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
Blk->getTerminator());
}
/// Visit - Walk the subtree of a statement and add extra
/// blocks for ternary operators, &&, and ||. We also process "," and
/// DeclStmts (which may contain nested control-flow).
CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
if (!S) {
badCFG = true;
return 0;
}
if (Expr *E = dyn_cast<Expr>(S))
S = E->IgnoreParens();
switch (S->getStmtClass()) {
default:
return VisitStmt(S, asc);
case Stmt::AddrLabelExprClass:
return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
case Stmt::BinaryConditionalOperatorClass:
return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
case Stmt::BinaryOperatorClass:
return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
case Stmt::BlockExprClass:
return VisitNoRecurse(cast<Expr>(S), asc);
case Stmt::BreakStmtClass:
return VisitBreakStmt(cast<BreakStmt>(S));
case Stmt::CallExprClass:
case Stmt::CXXOperatorCallExprClass:
case Stmt::CXXMemberCallExprClass:
case Stmt::UserDefinedLiteralClass:
return VisitCallExpr(cast<CallExpr>(S), asc);
case Stmt::CaseStmtClass:
return VisitCaseStmt(cast<CaseStmt>(S));
case Stmt::ChooseExprClass:
return VisitChooseExpr(cast<ChooseExpr>(S), asc);
case Stmt::CompoundStmtClass:
return VisitCompoundStmt(cast<CompoundStmt>(S));
case Stmt::ConditionalOperatorClass:
return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
case Stmt::ContinueStmtClass:
return VisitContinueStmt(cast<ContinueStmt>(S));
case Stmt::CXXCatchStmtClass:
return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
case Stmt::ExprWithCleanupsClass:
return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
case Stmt::CXXDefaultArgExprClass:
// FIXME: The expression inside a CXXDefaultArgExpr is owned by the
// called function's declaration, not by the caller. If we simply add
// this expression to the CFG, we could end up with the same Expr
// appearing multiple times.
// PR13385 / <rdar://problem/12156507>
return VisitStmt(S, asc);
case Stmt::CXXBindTemporaryExprClass:
return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
case Stmt::CXXConstructExprClass:
return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
case Stmt::CXXFunctionalCastExprClass:
return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
case Stmt::CXXTemporaryObjectExprClass:
return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
case Stmt::CXXThrowExprClass:
return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
case Stmt::CXXTryStmtClass:
return VisitCXXTryStmt(cast<CXXTryStmt>(S));
case Stmt::CXXForRangeStmtClass:
return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
case Stmt::DeclStmtClass:
return VisitDeclStmt(cast<DeclStmt>(S));
case Stmt::DefaultStmtClass:
return VisitDefaultStmt(cast<DefaultStmt>(S));
case Stmt::DoStmtClass:
return VisitDoStmt(cast<DoStmt>(S));
case Stmt::ForStmtClass:
return VisitForStmt(cast<ForStmt>(S));
case Stmt::GotoStmtClass:
return VisitGotoStmt(cast<GotoStmt>(S));
case Stmt::IfStmtClass:
return VisitIfStmt(cast<IfStmt>(S));
case Stmt::ImplicitCastExprClass:
return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
case Stmt::IndirectGotoStmtClass:
return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
case Stmt::LabelStmtClass:
return VisitLabelStmt(cast<LabelStmt>(S));
case Stmt::LambdaExprClass:
return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
case Stmt::MemberExprClass:
return VisitMemberExpr(cast<MemberExpr>(S), asc);
case Stmt::NullStmtClass:
return Block;
case Stmt::ObjCAtCatchStmtClass:
return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
case Stmt::ObjCAutoreleasePoolStmtClass:
return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
case Stmt::ObjCAtSynchronizedStmtClass:
return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
case Stmt::ObjCAtThrowStmtClass:
return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
case Stmt::ObjCAtTryStmtClass:
return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
case Stmt::ObjCForCollectionStmtClass:
return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
case Stmt::OpaqueValueExprClass:
return Block;
case Stmt::PseudoObjectExprClass:
return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
case Stmt::ReturnStmtClass:
return VisitReturnStmt(cast<ReturnStmt>(S));
case Stmt::UnaryExprOrTypeTraitExprClass:
return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
asc);
case Stmt::StmtExprClass:
return VisitStmtExpr(cast<StmtExpr>(S), asc);
case Stmt::SwitchStmtClass:
return VisitSwitchStmt(cast<SwitchStmt>(S));
case Stmt::UnaryOperatorClass:
return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
case Stmt::WhileStmtClass:
return VisitWhileStmt(cast<WhileStmt>(S));
}
}
CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
if (asc.alwaysAdd(*this, S)) {
autoCreateBlock();
appendStmt(Block, S);
}
return VisitChildren(S);
}
/// VisitChildren - Visit the children of a Stmt.
CFGBlock *CFGBuilder::VisitChildren(Stmt *Terminator) {
CFGBlock *lastBlock = Block;
for (Stmt::child_range I = Terminator->children(); I; ++I)
if (Stmt *child = *I)
if (CFGBlock *b = Visit(child))
lastBlock = b;
return lastBlock;
}
CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
AddStmtChoice asc) {
AddressTakenLabels.insert(A->getLabel());
if (asc.alwaysAdd(*this, A)) {
autoCreateBlock();
appendStmt(Block, A);
}
return Block;
}
CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
AddStmtChoice asc) {
if (asc.alwaysAdd(*this, U)) {
autoCreateBlock();
appendStmt(Block, U);
}
return Visit(U->getSubExpr(), AddStmtChoice());
}
CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
appendStmt(ConfluenceBlock, B);
if (badCFG)
return 0;
return VisitLogicalOperator(B, 0, ConfluenceBlock, ConfluenceBlock).first;
}
std::pair<CFGBlock*, CFGBlock*>
CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
Stmt *Term,
CFGBlock *TrueBlock,
CFGBlock *FalseBlock) {
// Introspect the RHS. If it is a nested logical operation, we recursively
// build the CFG using this function. Otherwise, resort to default
// CFG construction behavior.
Expr *RHS = B->getRHS()->IgnoreParens();
CFGBlock *RHSBlock, *ExitBlock;
do {
if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
if (B_RHS->isLogicalOp()) {
llvm::tie(RHSBlock, ExitBlock) =
VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
break;
}
// The RHS is not a nested logical operation. Don't push the terminator
// down further, but instead visit RHS and construct the respective
// pieces of the CFG, and link up the RHSBlock with the terminator
// we have been provided.
ExitBlock = RHSBlock = createBlock(false);
if (!Term) {
assert(TrueBlock == FalseBlock);
addSuccessor(RHSBlock, TrueBlock);
}
else {
RHSBlock->setTerminator(Term);
TryResult KnownVal = tryEvaluateBool(RHS);
addSuccessor(RHSBlock, KnownVal.isFalse() ? NULL : TrueBlock);
addSuccessor(RHSBlock, KnownVal.isTrue() ? NULL : FalseBlock);
}
Block = RHSBlock;
RHSBlock = addStmt(RHS);
}
while (false);
if (badCFG)
return std::make_pair((CFGBlock*)0, (CFGBlock*)0);
// Generate the blocks for evaluating the LHS.
Expr *LHS = B->getLHS()->IgnoreParens();
if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
if (B_LHS->isLogicalOp()) {
if (B->getOpcode() == BO_LOr)
FalseBlock = RHSBlock;
else
TrueBlock = RHSBlock;
// For the LHS, treat 'B' as the terminator that we want to sink
// into the nested branch. The RHS always gets the top-most
// terminator.
return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
}
// Create the block evaluating the LHS.
// This contains the '&&' or '||' as the terminator.
CFGBlock *LHSBlock = createBlock(false);
LHSBlock->setTerminator(B);
Block = LHSBlock;
CFGBlock *EntryLHSBlock = addStmt(LHS);
if (badCFG)
return std::make_pair((CFGBlock*)0, (CFGBlock*)0);
// See if this is a known constant.
TryResult KnownVal = tryEvaluateBool(LHS);
// Now link the LHSBlock with RHSBlock.
if (B->getOpcode() == BO_LOr) {
addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : TrueBlock);
addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : RHSBlock);
} else {
assert(B->getOpcode() == BO_LAnd);
addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : FalseBlock);
}
return std::make_pair(EntryLHSBlock, ExitBlock);
}
CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
AddStmtChoice asc) {
// && or ||
if (B->isLogicalOp())
return VisitLogicalOperator(B);
if (B->getOpcode() == BO_Comma) { // ,
autoCreateBlock();
appendStmt(Block, B);
addStmt(B->getRHS());
return addStmt(B->getLHS());
}
if (B->isAssignmentOp()) {
if (asc.alwaysAdd(*this, B)) {
autoCreateBlock();
appendStmt(Block, B);
}
Visit(B->getLHS());
return Visit(B->getRHS());
}
if (asc.alwaysAdd(*this, B)) {
autoCreateBlock();
appendStmt(Block, B);
}
CFGBlock *RBlock = Visit(B->getRHS());
CFGBlock *LBlock = Visit(B->getLHS());
// If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
// containing a DoStmt, and the LHS doesn't create a new block, then we should
// return RBlock. Otherwise we'll incorrectly return NULL.
return (LBlock ? LBlock : RBlock);
}
CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
if (asc.alwaysAdd(*this, E)) {
autoCreateBlock();
appendStmt(Block, E);
}
return Block;
}
CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
// "break" is a control-flow statement. Thus we stop processing the current
// block.
if (badCFG)
return 0;
// Now create a new block that ends with the break statement.
Block = createBlock(false);
Block->setTerminator(B);
// If there is no target for the break, then we are looking at an incomplete
// AST. This means that the CFG cannot be constructed.
if (BreakJumpTarget.block) {
addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B);
addSuccessor(Block, BreakJumpTarget.block);
} else
badCFG = true;
return Block;
}
static bool CanThrow(Expr *E, ASTContext &Ctx) {
QualType Ty = E->getType();
if (Ty->isFunctionPointerType())
Ty = Ty->getAs<PointerType>()->getPointeeType();
else if (Ty->isBlockPointerType())
Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
const FunctionType *FT = Ty->getAs<FunctionType>();
if (FT) {
if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
Proto->isNothrow(Ctx))
return false;
}
return true;
}
CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
// Compute the callee type.
QualType calleeType = C->getCallee()->getType();
if (calleeType == Context->BoundMemberTy) {
QualType boundType = Expr::findBoundMemberType(C->getCallee());
// We should only get a null bound type if processing a dependent
// CFG. Recover by assuming nothing.
if (!boundType.isNull()) calleeType = boundType;
}
// If this is a call to a no-return function, this stops the block here.
bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
bool AddEHEdge = false;
// Languages without exceptions are assumed to not throw.
if (Context->getLangOpts().Exceptions) {
if (BuildOpts.AddEHEdges)
AddEHEdge = true;
}
if (FunctionDecl *FD = C->getDirectCallee()) {
if (FD->isNoReturn())
NoReturn = true;
if (FD->hasAttr<NoThrowAttr>())
AddEHEdge = false;
}
if (!CanThrow(C->getCallee(), *Context))
AddEHEdge = false;
if (!NoReturn && !AddEHEdge)
return VisitStmt(C, asc.withAlwaysAdd(true));
if (Block) {
Succ = Block;
if (badCFG)
return 0;
}
if (NoReturn)
Block = createNoReturnBlock();
else
Block = createBlock();
appendStmt(Block, C);
if (AddEHEdge) {
// Add exceptional edges.
if (TryTerminatedBlock)
addSuccessor(Block, TryTerminatedBlock);
else
addSuccessor(Block, &cfg->getExit());
}
return VisitChildren(C);
}
CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
AddStmtChoice asc) {
CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
appendStmt(ConfluenceBlock, C);
if (badCFG)
return 0;
AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
Succ = ConfluenceBlock;
Block = NULL;
CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
if (badCFG)
return 0;
Succ = ConfluenceBlock;
Block = NULL;
CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
if (badCFG)
return 0;
Block = createBlock(false);
// See if this is a known constant.
const TryResult& KnownVal = tryEvaluateBool(C->getCond());
addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
Block->setTerminator(C);
return addStmt(C->getCond());
}
CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
addLocalScopeAndDtors(C);
CFGBlock *LastBlock = Block;
for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend();
I != E; ++I ) {
// If we hit a segment of code just containing ';' (NullStmts), we can
// get a null block back. In such cases, just use the LastBlock
if (CFGBlock *newBlock = addStmt(*I))
LastBlock = newBlock;
if (badCFG)
return NULL;
}
return LastBlock;
}
CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
AddStmtChoice asc) {
const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL);
// Create the confluence block that will "merge" the results of the ternary
// expression.
CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
appendStmt(ConfluenceBlock, C);
if (badCFG)
return 0;
AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
// Create a block for the LHS expression if there is an LHS expression. A
// GCC extension allows LHS to be NULL, causing the condition to be the
// value that is returned instead.
// e.g: x ?: y is shorthand for: x ? x : y;
Succ = ConfluenceBlock;
Block = NULL;
CFGBlock *LHSBlock = 0;
const Expr *trueExpr = C->getTrueExpr();
if (trueExpr != opaqueValue) {
LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
if (badCFG)
return 0;
Block = NULL;
}
else
LHSBlock = ConfluenceBlock;
// Create the block for the RHS expression.
Succ = ConfluenceBlock;
CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
if (badCFG)
return 0;
// If the condition is a logical '&&' or '||', build a more accurate CFG.
if (BinaryOperator *Cond =
dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
if (Cond->isLogicalOp())
return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
// Create the block that will contain the condition.
Block = createBlock(false);
// See if this is a known constant.
const TryResult& KnownVal = tryEvaluateBool(C->getCond());
addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
Block->setTerminator(C);
Expr *condExpr = C->getCond();
if (opaqueValue) {
// Run the condition expression if it's not trivially expressed in
// terms of the opaque value (or if there is no opaque value).
if (condExpr != opaqueValue)
addStmt(condExpr);
// Before that, run the common subexpression if there was one.
// At least one of this or the above will be run.
return addStmt(BCO->getCommon());
}
return addStmt(condExpr);
}
CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
// Check if the Decl is for an __label__. If so, elide it from the
// CFG entirely.
if (isa<LabelDecl>(*DS->decl_begin()))
return Block;
// This case also handles static_asserts.
if (DS->isSingleDecl())
return VisitDeclSubExpr(DS);
CFGBlock *B = 0;
// Build an individual DeclStmt for each decl.
for (DeclStmt::reverse_decl_iterator I = DS->decl_rbegin(),
E = DS->decl_rend();
I != E; ++I) {
// Get the alignment of the new DeclStmt, padding out to >=8 bytes.
unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8
? 8 : llvm::AlignOf<DeclStmt>::Alignment;
// Allocate the DeclStmt using the BumpPtrAllocator. It will get
// automatically freed with the CFG.
DeclGroupRef DG(*I);
Decl *D = *I;
void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
// Append the fake DeclStmt to block.
B = VisitDeclSubExpr(DSNew);
}
return B;
}
/// VisitDeclSubExpr - Utility method to add block-level expressions for
/// DeclStmts and initializers in them.
CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
assert(DS->isSingleDecl() && "Can handle single declarations only.");
Decl *D = DS->getSingleDecl();
if (isa<StaticAssertDecl>(D)) {
// static_asserts aren't added to the CFG because they do not impact
// runtime semantics.
return Block;
}
VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
if (!VD) {
autoCreateBlock();
appendStmt(Block, DS);
return Block;
}
bool IsReference = false;
bool HasTemporaries = false;
// Destructors of temporaries in initialization expression should be called
// after initialization finishes.
Expr *Init = VD->getInit();
if (Init) {
IsReference = VD->getType()->isReferenceType();
HasTemporaries = isa<ExprWithCleanups>(Init);
if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
// Generate destructors for temporaries in initialization expression.
VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
IsReference);
}
}
autoCreateBlock();
appendStmt(Block, DS);
// Keep track of the last non-null block, as 'Block' can be nulled out
// if the initializer expression is something like a 'while' in a
// statement-expression.
CFGBlock *LastBlock = Block;
if (Init) {
if (HasTemporaries) {
// For expression with temporaries go directly to subexpression to omit
// generating destructors for the second time.
ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
LastBlock = newBlock;
}
else {
if (CFGBlock *newBlock = Visit(Init))
LastBlock = newBlock;
}
}
// If the type of VD is a VLA, then we must process its size expressions.
for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) {
if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
LastBlock = newBlock;
}
// Remove variable from local scope.
if (ScopePos && VD == *ScopePos)
++ScopePos;
return Block ? Block : LastBlock;
}
CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
// We may see an if statement in the middle of a basic block, or it may be the
// first statement we are processing. In either case, we create a new basic
// block. First, we create the blocks for the then...else statements, and
// then we create the block containing the if statement. If we were in the
// middle of a block, we stop processing that block. That block is then the
// implicit successor for the "then" and "else" clauses.
// Save local scope position because in case of condition variable ScopePos
// won't be restored when traversing AST.
SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
// Create local scope for possible condition variable.
// Store scope position. Add implicit destructor.
if (VarDecl *VD = I->getConditionVariable()) {
LocalScope::const_iterator BeginScopePos = ScopePos;
addLocalScopeForVarDecl(VD);
addAutomaticObjDtors(ScopePos, BeginScopePos, I);
}
// The block we were processing is now finished. Make it the successor
// block.
if (Block) {
Succ = Block;
if (badCFG)
return 0;
}
// Process the false branch.
CFGBlock *ElseBlock = Succ;
if (Stmt *Else = I->getElse()) {
SaveAndRestore<CFGBlock*> sv(Succ);
// NULL out Block so that the recursive call to Visit will
// create a new basic block.
Block = NULL;
// If branch is not a compound statement create implicit scope
// and add destructors.
if (!isa<CompoundStmt>(Else))
addLocalScopeAndDtors(Else);
ElseBlock = addStmt(Else);
if (!ElseBlock) // Can occur when the Else body has all NullStmts.
ElseBlock = sv.get();
else if (Block) {
if (badCFG)
return 0;
}
}
// Process the true branch.
CFGBlock *ThenBlock;
{
Stmt *Then = I->getThen();
assert(Then);
SaveAndRestore<CFGBlock*> sv(Succ);
Block = NULL;
// If branch is not a compound statement create implicit scope
// and add destructors.
if (!isa<CompoundStmt>(Then))
addLocalScopeAndDtors(Then);
ThenBlock = addStmt(Then);
if (!ThenBlock) {
// We can reach here if the "then" body has all NullStmts.
// Create an empty block so we can distinguish between true and false
// branches in path-sensitive analyses.
ThenBlock = createBlock(false);
addSuccessor(ThenBlock, sv.get());
} else if (Block) {
if (badCFG)
return 0;
}
}
// Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
// having these handle the actual control-flow jump. Note that
// if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
// we resort to the old control-flow behavior. This special handling
// removes infeasible paths from the control-flow graph by having the
// control-flow transfer of '&&' or '||' go directly into the then/else
// blocks directly.
if (!I->getConditionVariable())
if (BinaryOperator *Cond =
dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens()))
if (Cond->isLogicalOp())
return VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
// Now create a new block containing the if statement.
Block = createBlock(false);
// Set the terminator of the new block to the If statement.
Block->setTerminator(I);
// See if this is a known constant.
const TryResult &KnownVal = tryEvaluateBool(I->getCond());
// Now add the successors.
addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock);
addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock);
// Add the condition as the last statement in the new block. This may create
// new blocks as the condition may contain control-flow. Any newly created
// blocks will be pointed to be "Block".
CFGBlock *LastBlock = addStmt(I->getCond());
// Finally, if the IfStmt contains a condition variable, add both the IfStmt
// and the condition variable initialization to the CFG.
if (VarDecl *VD = I->getConditionVariable()) {
if (Expr *Init = VD->getInit()) {
autoCreateBlock();
appendStmt(Block, I->getConditionVariableDeclStmt());
LastBlock = addStmt(Init);
}
}
return LastBlock;
}
CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
// If we were in the middle of a block we stop processing that block.
//
// NOTE: If a "return" appears in the middle of a block, this means that the
// code afterwards is DEAD (unreachable). We still keep a basic block
// for that code; a simple "mark-and-sweep" from the entry block will be
// able to report such dead blocks.
// Create the new block.
Block = createBlock(false);
// The Exit block is the only successor.
addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R);
addSuccessor(Block, &cfg->getExit());
// Add the return statement to the block. This may create new blocks if R
// contains control-flow (short-circuit operations).
return VisitStmt(R, AddStmtChoice::AlwaysAdd);
}
CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
// Get the block of the labeled statement. Add it to our map.
addStmt(L->getSubStmt());
CFGBlock *LabelBlock = Block;
if (!LabelBlock) // This can happen when the body is empty, i.e.
LabelBlock = createBlock(); // scopes that only contains NullStmts.
assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
"label already in map");
LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
// Labels partition blocks, so this is the end of the basic block we were
// processing (L is the block's label). Because this is label (and we have
// already processed the substatement) there is no extra control-flow to worry
// about.
LabelBlock->setLabel(L);
if (badCFG)
return 0;
// We set Block to NULL to allow lazy creation of a new block (if necessary);
Block = NULL;
// This block is now the implicit successor of other blocks.
Succ = LabelBlock;
return LabelBlock;
}
CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
CFGBlock *LastBlock = VisitNoRecurse(E, asc);
for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(),
et = E->capture_init_end(); it != et; ++it) {
if (Expr *Init = *it) {
CFGBlock *Tmp = Visit(Init);
if (Tmp != 0)
LastBlock = Tmp;
}
}
return LastBlock;
}
CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
// Goto is a control-flow statement. Thus we stop processing the current
// block and create a new one.
Block = createBlock(false);
Block->setTerminator(G);
// If we already know the mapping to the label block add the successor now.
LabelMapTy::iterator I = LabelMap.find(G->getLabel());
if (I == LabelMap.end())
// We will need to backpatch this block later.
BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
else {
JumpTarget JT = I->second;
addAutomaticObjDtors(ScopePos, JT.scopePosition, G);
addSuccessor(Block, JT.block);
}
return Block;
}
CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
CFGBlock *LoopSuccessor = NULL;
// Save local scope position because in case of condition variable ScopePos
// won't be restored when traversing AST.
SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
// Create local scope for init statement and possible condition variable.
// Add destructor for init statement and condition variable.
// Store scope position for continue statement.
if (Stmt *Init = F->getInit())
addLocalScopeForStmt(Init);
LocalScope::const_iterator LoopBeginScopePos = ScopePos;
if (VarDecl *VD = F->getConditionVariable())
addLocalScopeForVarDecl(VD);
LocalScope::const_iterator ContinueScopePos = ScopePos;
addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F);
// "for" is a control-flow statement. Thus we stop processing the current
// block.
if (Block) {
if (badCFG)
return 0;
LoopSuccessor = Block;
} else
LoopSuccessor = Succ;
// Save the current value for the break targets.
// All breaks should go to the code following the loop.
SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
CFGBlock *BodyBlock = 0, *TransitionBlock = 0;
// Now create the loop body.
{
assert(F->getBody());
// Save the current values for Block, Succ, continue and break targets.
SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
// Create an empty block to represent the transition block for looping back
// to the head of the loop. If we have increment code, it will
// go in this block as well.
Block = Succ = TransitionBlock = createBlock(false);
TransitionBlock->setLoopTarget(F);
if (Stmt *I = F->getInc()) {
// Generate increment code in its own basic block. This is the target of
// continue statements.
Succ = addStmt(I);
}
// Finish up the increment (or empty) block if it hasn't been already.
if (Block) {
assert(Block == Succ);
if (badCFG)
return 0;
Block = 0;
}
// The starting block for the loop increment is the block that should
// represent the 'loop target' for looping back to the start of the loop.
ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
ContinueJumpTarget.block->setLoopTarget(F);
// Loop body should end with destructor of Condition variable (if any).
addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F);
// If body is not a compound statement create implicit scope
// and add destructors.
if (!isa<CompoundStmt>(F->getBody()))
addLocalScopeAndDtors(F->getBody());
// Now populate the body block, and in the process create new blocks as we
// walk the body of the loop.
BodyBlock = addStmt(F->getBody());
if (!BodyBlock) {
// In the case of "for (...;...;...);" we can have a null BodyBlock.
// Use the continue jump target as the proxy for the body.
BodyBlock = ContinueJumpTarget.block;
}
else if (badCFG)
return 0;
}
// Because of short-circuit evaluation, the condition of the loop can span
// multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
// evaluate the condition.
CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0;
do {
Expr *C = F->getCond();
// Specially handle logical operators, which have a slightly
// more optimal CFG representation.
if (BinaryOperator *Cond =
dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : 0))
if (Cond->isLogicalOp()) {
llvm::tie(EntryConditionBlock, ExitConditionBlock) =
VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
break;
}
// The default case when not handling logical operators.
EntryConditionBlock = ExitConditionBlock = createBlock(false);
ExitConditionBlock->setTerminator(F);
// See if this is a known constant.
TryResult KnownVal(true);
if (C) {
// Now add the actual condition to the condition block.
// Because the condition itself may contain control-flow, new blocks may
// be created. Thus we update "Succ" after adding the condition.
Block = ExitConditionBlock;
EntryConditionBlock = addStmt(C);
// If this block contains a condition variable, add both the condition
// variable and initializer to the CFG.
if (VarDecl *VD = F->getConditionVariable()) {
if (Expr *Init = VD->getInit()) {
autoCreateBlock();
appendStmt(Block, F->getConditionVariableDeclStmt());
EntryConditionBlock = addStmt(Init);
assert(Block == EntryConditionBlock);
}
}
if (Block && badCFG)
return 0;
KnownVal = tryEvaluateBool(C);
}
// Add the loop body entry as a successor to the condition.
addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock);
// Link up the condition block with the code that follows the loop. (the
// false branch).
addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
} while (false);
// Link up the loop-back block to the entry condition block.
addSuccessor(TransitionBlock, EntryConditionBlock);
// The condition block is the implicit successor for any code above the loop.
Succ = EntryConditionBlock;
// If the loop contains initialization, create a new block for those
// statements. This block can also contain statements that precede the loop.
if (Stmt *I = F->getInit()) {
Block = createBlock();
return addStmt(I);
}
// There is no loop initialization. We are thus basically a while loop.
// NULL out Block to force lazy block construction.
Block = NULL;
Succ = EntryConditionBlock;
return EntryConditionBlock;
}
CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
if (asc.alwaysAdd(*this, M)) {
autoCreateBlock();
appendStmt(Block, M);
}
return Visit(M->getBase());
}
CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
// Objective-C fast enumeration 'for' statements:
// http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
//
// for ( Type newVariable in collection_expression ) { statements }
//
// becomes:
//
// prologue:
// 1. collection_expression
// T. jump to loop_entry
// loop_entry:
// 1. side-effects of element expression
// 1. ObjCForCollectionStmt [performs binding to newVariable]
// T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
// TB:
// statements
// T. jump to loop_entry
// FB:
// what comes after
//
// and
//
// Type existingItem;
// for ( existingItem in expression ) { statements }
//
// becomes:
//
// the same with newVariable replaced with existingItem; the binding works
// the same except that for one ObjCForCollectionStmt::getElement() returns
// a DeclStmt and the other returns a DeclRefExpr.
//
CFGBlock *LoopSuccessor = 0;
if (Block) {
if (badCFG)
return 0;
LoopSuccessor = Block;
Block = 0;
} else
LoopSuccessor = Succ;
// Build the condition blocks.
CFGBlock *ExitConditionBlock = createBlock(false);
// Set the terminator for the "exit" condition block.
ExitConditionBlock->setTerminator(S);
// The last statement in the block should be the ObjCForCollectionStmt, which
// performs the actual binding to 'element' and determines if there are any
// more items in the collection.
appendStmt(ExitConditionBlock, S);
Block = ExitConditionBlock;
// Walk the 'element' expression to see if there are any side-effects. We
// generate new blocks as necessary. We DON'T add the statement by default to
// the CFG unless it contains control-flow.
CFGBlock *EntryConditionBlock = Visit(S->getElement(),
AddStmtChoice::NotAlwaysAdd);
if (Block) {
if (badCFG)
return 0;
Block = 0;
}
// The condition block is the implicit successor for the loop body as well as
// any code above the loop.
Succ = EntryConditionBlock;
// Now create the true branch.
{
// Save the current values for Succ, continue and break targets.
SaveAndRestore<CFGBlock*> save_Succ(Succ);
SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
save_break(BreakJumpTarget);
BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
CFGBlock *BodyBlock = addStmt(S->getBody());
if (!BodyBlock)
BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;"
else if (Block) {
if (badCFG)
return 0;
}
// This new body block is a successor to our "exit" condition block.
addSuccessor(ExitConditionBlock, BodyBlock);
}
// Link up the condition block with the code that follows the loop.
// (the false branch).
addSuccessor(ExitConditionBlock, LoopSuccessor);
// Now create a prologue block to contain the collection expression.
Block = createBlock();
return addStmt(S->getCollection());
}
CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
// Inline the body.
return addStmt(S->getSubStmt());
// TODO: consider adding cleanups for the end of @autoreleasepool scope.
}
CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
// FIXME: Add locking 'primitives' to CFG for @synchronized.
// Inline the body.
CFGBlock *SyncBlock = addStmt(S->getSynchBody());
// The sync body starts its own basic block. This makes it a little easier
// for diagnostic clients.
if (SyncBlock) {
if (badCFG)
return 0;
Block = 0;
Succ = SyncBlock;
}
// Add the @synchronized to the CFG.
autoCreateBlock();
appendStmt(Block, S);
// Inline the sync expression.
return addStmt(S->getSynchExpr());
}
CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
// FIXME
return NYS();
}
CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
autoCreateBlock();
// Add the PseudoObject as the last thing.
appendStmt(Block, E);
CFGBlock *lastBlock = Block;
// Before that, evaluate all of the semantics in order. In
// CFG-land, that means appending them in reverse order.
for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
Expr *Semantic = E->getSemanticExpr(--i);
// If the semantic is an opaque value, we're being asked to bind
// it to its source expression.
if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
Semantic = OVE->getSourceExpr();
if (CFGBlock *B = Visit(Semantic))
lastBlock = B;
}
return lastBlock;
}
CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
CFGBlock *LoopSuccessor = NULL;
// Save local scope position because in case of condition variable ScopePos
// won't be restored when traversing AST.
SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
// Create local scope for possible condition variable.
// Store scope position for continue statement.
LocalScope::const_iterator LoopBeginScopePos = ScopePos;
if (VarDecl *VD = W->getConditionVariable()) {
addLocalScopeForVarDecl(VD);
addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W);
}
// "while" is a control-flow statement. Thus we stop processing the current
// block.
if (Block) {
if (badCFG)
return 0;
LoopSuccessor = Block;
Block = 0;
} else {
LoopSuccessor = Succ;
}
CFGBlock *BodyBlock = 0, *TransitionBlock = 0;
// Process the loop body.
{
assert(W->getBody());
// Save the current values for Block, Succ, continue and break targets.
SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
save_break(BreakJumpTarget);
// Create an empty block to represent the transition block for looping back
// to the head of the loop.
Succ = TransitionBlock = createBlock(false);
TransitionBlock->setLoopTarget(W);
ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
// All breaks should go to the code following the loop.
BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
// Loop body should end with destructor of Condition variable (if any).
addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W);
// If body is not a compound statement create implicit scope
// and add destructors.
if (!isa<CompoundStmt>(W->getBody()))
addLocalScopeAndDtors(W->getBody());
// Create the body. The returned block is the entry to the loop body.
BodyBlock = addStmt(W->getBody());
if (!BodyBlock)
BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
else if (Block && badCFG)
return 0;
}
// Because of short-circuit evaluation, the condition of the loop can span
// multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
// evaluate the condition.
CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0;
do {
Expr *C = W->getCond();
// Specially handle logical operators, which have a slightly
// more optimal CFG representation.
if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
if (Cond->isLogicalOp()) {
llvm::tie(EntryConditionBlock, ExitConditionBlock) =
VisitLogicalOperator(Cond, W, BodyBlock,
LoopSuccessor);
break;
}
// The default case when not handling logical operators.
ExitConditionBlock = createBlock(false);
ExitConditionBlock->setTerminator(W);
// Now add the actual condition to the condition block.
// Because the condition itself may contain control-flow, new blocks may
// be created. Thus we update "Succ" after adding the condition.
Block = ExitConditionBlock;
Block = EntryConditionBlock = addStmt(C);
// If this block contains a condition variable, add both the condition
// variable and initializer to the CFG.
if (VarDecl *VD = W->getConditionVariable()) {
if (Expr *Init = VD->getInit()) {
autoCreateBlock();
appendStmt(Block, W->getConditionVariableDeclStmt());
EntryConditionBlock = addStmt(Init);
assert(Block == EntryConditionBlock);
}
}
if (Block && badCFG)
return 0;
// See if this is a known constant.
const TryResult& KnownVal = tryEvaluateBool(C);
// Add the loop body entry as a successor to the condition.
addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock);
// Link up the condition block with the code that follows the loop. (the
// false branch).
addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
} while(false);
// Link up the loop-back block to the entry condition block.
addSuccessor(TransitionBlock, EntryConditionBlock);
// There can be no more statements in the condition block since we loop back
// to this block. NULL out Block to force lazy creation of another block.
Block = NULL;
// Return the condition block, which is the dominating block for the loop.
Succ = EntryConditionBlock;
return EntryConditionBlock;
}
CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
// FIXME: For now we pretend that @catch and the code it contains does not
// exit.
return Block;
}
CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
// FIXME: This isn't complete. We basically treat @throw like a return
// statement.
// If we were in the middle of a block we stop processing that block.
if (badCFG)
return 0;
// Create the new block.
Block = createBlock(false);
// The Exit block is the only successor.
addSuccessor(Block, &cfg->getExit());
// Add the statement to the block. This may create new blocks if S contains
// control-flow (short-circuit operations).
return VisitStmt(S, AddStmtChoice::AlwaysAdd);
}
CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
// If we were in the middle of a block we stop processing that block.
if (badCFG)
return 0;
// Create the new block.
Block = createBlock(false);
if (TryTerminatedBlock)
// The current try statement is the only successor.
addSuccessor(Block, TryTerminatedBlock);
else
// otherwise the Exit block is the only successor.
addSuccessor(Block, &cfg->getExit());
// Add the statement to the block. This may create new blocks if S contains
// control-flow (short-circuit operations).
return VisitStmt(T, AddStmtChoice::AlwaysAdd);
}
CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
CFGBlock *LoopSuccessor = NULL;
// "do...while" is a control-flow statement. Thus we stop processing the
// current block.
if (Block) {
if (badCFG)
return 0;
LoopSuccessor = Block;
} else
LoopSuccessor = Succ;
// Because of short-circuit evaluation, the condition of the loop can span
// multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
// evaluate the condition.
CFGBlock *ExitConditionBlock = createBlock(false);
CFGBlock *EntryConditionBlock = ExitConditionBlock;
// Set the terminator for the "exit" condition block.
ExitConditionBlock->setTerminator(D);
// Now add the actual condition to the condition block. Because the condition
// itself may contain control-flow, new blocks may be created.
if (Stmt *C = D->getCond()) {
Block = ExitConditionBlock;
EntryConditionBlock = addStmt(C);
if (Block) {
if (badCFG)
return 0;
}
}
// The condition block is the implicit successor for the loop body.
Succ = EntryConditionBlock;
// See if this is a known constant.
const TryResult &KnownVal = tryEvaluateBool(D->getCond());
// Process the loop body.
CFGBlock *BodyBlock = NULL;
{
assert(D->getBody());
// Save the current values for Block, Succ, and continue and break targets
SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
save_break(BreakJumpTarget);
// All continues within this loop should go to the condition block
ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
// All breaks should go to the code following the loop.
BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
// NULL out Block to force lazy instantiation of blocks for the body.
Block = NULL;
// If body is not a compound statement create implicit scope
// and add destructors.
if (!isa<CompoundStmt>(D->getBody()))
addLocalScopeAndDtors(D->getBody());
// Create the body. The returned block is the entry to the loop body.
BodyBlock = addStmt(D->getBody());
if (!BodyBlock)
BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
else if (Block) {
if (badCFG)
return 0;
}
if (!KnownVal.isFalse()) {
// Add an intermediate block between the BodyBlock and the
// ExitConditionBlock to represent the "loop back" transition. Create an
// empty block to represent the transition block for looping back to the
// head of the loop.
// FIXME: Can we do this more efficiently without adding another block?
Block = NULL;
Succ = BodyBlock;
CFGBlock *LoopBackBlock = createBlock();
LoopBackBlock->setLoopTarget(D);
// Add the loop body entry as a successor to the condition.
addSuccessor(ExitConditionBlock, LoopBackBlock);
}
else
addSuccessor(ExitConditionBlock, NULL);
}
// Link up the condition block with the code that follows the loop.
// (the false branch).
addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
// There can be no more statements in the body block(s) since we loop back to
// the body. NULL out Block to force lazy creation of another block.
Block = NULL;
// Return the loop body, which is the dominating block for the loop.
Succ = BodyBlock;
return BodyBlock;
}
CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
// "continue" is a control-flow statement. Thus we stop processing the
// current block.
if (badCFG)
return 0;
// Now create a new block that ends with the continue statement.
Block = createBlock(false);
Block->setTerminator(C);
// If there is no target for the continue, then we are looking at an
// incomplete AST. This means the CFG cannot be constructed.
if (ContinueJumpTarget.block) {
addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C);
addSuccessor(Block, ContinueJumpTarget.block);
} else
badCFG = true;
return Block;
}
CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
AddStmtChoice asc) {
if (asc.alwaysAdd(*this, E)) {
autoCreateBlock();
appendStmt(Block, E);
}
// VLA types have expressions that must be evaluated.
CFGBlock *lastBlock = Block;
if (E->isArgumentType()) {
for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
VA != 0; VA = FindVA(VA->getElementType().getTypePtr()))
lastBlock = addStmt(VA->getSizeExpr());
}
return lastBlock;
}
/// VisitStmtExpr - Utility method to handle (nested) statement
/// expressions (a GCC extension).
CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
if (asc.alwaysAdd(*this, SE)) {
autoCreateBlock();
appendStmt(Block, SE);
}
return VisitCompoundStmt(SE->getSubStmt());
}
CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
// "switch" is a control-flow statement. Thus we stop processing the current
// block.
CFGBlock *SwitchSuccessor = NULL;
// Save local scope position because in case of condition variable ScopePos
// won't be restored when traversing AST.
SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
// Create local scope for possible condition variable.
// Store scope position. Add implicit destructor.
if (VarDecl *VD = Terminator->getConditionVariable()) {
LocalScope::const_iterator SwitchBeginScopePos = ScopePos;
addLocalScopeForVarDecl(VD);
addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator);
}
if (Block) {
if (badCFG)
return 0;
SwitchSuccessor = Block;
} else SwitchSuccessor = Succ;
// Save the current "switch" context.
SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
save_default(DefaultCaseBlock);
SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
// Set the "default" case to be the block after the switch statement. If the
// switch statement contains a "default:", this value will be overwritten with
// the block for that code.
DefaultCaseBlock = SwitchSuccessor;
// Create a new block that will contain the switch statement.
SwitchTerminatedBlock = createBlock(false);
// Now process the switch body. The code after the switch is the implicit
// successor.
Succ = SwitchSuccessor;
BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
// When visiting the body, the case statements should automatically get linked
// up to the switch. We also don't keep a pointer to the body, since all
// control-flow from the switch goes to case/default statements.
assert(Terminator->getBody() && "switch must contain a non-NULL body");
Block = NULL;
// For pruning unreachable case statements, save the current state
// for tracking the condition value.
SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
false);
// Determine if the switch condition can be explicitly evaluated.
assert(Terminator->getCond() && "switch condition must be non-NULL");
Expr::EvalResult result;
bool b = tryEvaluate(Terminator->getCond(), result);
SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
b ? &result : 0);
// If body is not a compound statement create implicit scope
// and add destructors.
if (!isa<CompoundStmt>(Terminator->getBody()))
addLocalScopeAndDtors(Terminator->getBody());
addStmt(Terminator->getBody());
if (Block) {
if (badCFG)
return 0;
}
// If we have no "default:" case, the default transition is to the code
// following the switch body. Moreover, take into account if all the
// cases of a switch are covered (e.g., switching on an enum value).
addSuccessor(SwitchTerminatedBlock,
switchExclusivelyCovered || Terminator->isAllEnumCasesCovered()
? 0 : DefaultCaseBlock);
// Add the terminator and condition in the switch block.
SwitchTerminatedBlock->setTerminator(Terminator);
Block = SwitchTerminatedBlock;
CFGBlock *LastBlock = addStmt(Terminator->getCond());
// Finally, if the SwitchStmt contains a condition variable, add both the
// SwitchStmt and the condition variable initialization to the CFG.
if (VarDecl *VD = Terminator->getConditionVariable()) {
if (Expr *Init = VD->getInit()) {
autoCreateBlock();
appendStmt(Block, Terminator->getConditionVariableDeclStmt());
LastBlock = addStmt(Init);
}
}
return LastBlock;
}
static bool shouldAddCase(bool &switchExclusivelyCovered,
const Expr::EvalResult *switchCond,
const CaseStmt *CS,
ASTContext &Ctx) {
if (!switchCond)
return true;
bool addCase = false;
if (!switchExclusivelyCovered) {
if (switchCond->Val.isInt()) {
// Evaluate the LHS of the case value.
const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
const llvm::APSInt &condInt = switchCond->Val.getInt();
if (condInt == lhsInt) {
addCase = true;
switchExclusivelyCovered = true;
}
else if (condInt < lhsInt) {
if (const Expr *RHS = CS->getRHS()) {
// Evaluate the RHS of the case value.
const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
if (V2 <= condInt) {
addCase = true;
switchExclusivelyCovered = true;
}
}
}
}
else
addCase = true;
}
return addCase;
}
CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
// CaseStmts are essentially labels, so they are the first statement in a
// block.
CFGBlock *TopBlock = 0, *LastBlock = 0;
if (Stmt *Sub = CS->getSubStmt()) {
// For deeply nested chains of CaseStmts, instead of doing a recursion
// (which can blow out the stack), manually unroll and create blocks
// along the way.
while (isa<CaseStmt>(Sub)) {
CFGBlock *currentBlock = createBlock(false);
currentBlock->setLabel(CS);
if (TopBlock)
addSuccessor(LastBlock, currentBlock);
else
TopBlock = currentBlock;
addSuccessor(SwitchTerminatedBlock,
shouldAddCase(switchExclusivelyCovered, switchCond,
CS, *Context)
? currentBlock : 0);
LastBlock = currentBlock;
CS = cast<CaseStmt>(Sub);
Sub = CS->getSubStmt();
}
addStmt(Sub);
}
CFGBlock *CaseBlock = Block;
if (!CaseBlock)
CaseBlock = createBlock();
// Cases statements partition blocks, so this is the top of the basic block we
// were processing (the "case XXX:" is the label).
CaseBlock->setLabel(CS);
if (badCFG)
return 0;
// Add this block to the list of successors for the block with the switch
// statement.
assert(SwitchTerminatedBlock);
addSuccessor(SwitchTerminatedBlock,
shouldAddCase(switchExclusivelyCovered, switchCond,
CS, *Context)
? CaseBlock : 0);
// We set Block to NULL to allow lazy creation of a new block (if necessary)
Block = NULL;
if (TopBlock) {
addSuccessor(LastBlock, CaseBlock);
Succ = TopBlock;
} else {
// This block is now the implicit successor of other blocks.
Succ = CaseBlock;
}
return Succ;
}
CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
if (Terminator->getSubStmt())
addStmt(Terminator->getSubStmt());
DefaultCaseBlock = Block;
if (!DefaultCaseBlock)
DefaultCaseBlock = createBlock();
// Default statements partition blocks, so this is the top of the basic block
// we were processing (the "default:" is the label).
DefaultCaseBlock->setLabel(Terminator);
if (badCFG)
return 0;
// Unlike case statements, we don't add the default block to the successors
// for the switch statement immediately. This is done when we finish
// processing the switch statement. This allows for the default case
// (including a fall-through to the code after the switch statement) to always
// be the last successor of a switch-terminated block.
// We set Block to NULL to allow lazy creation of a new block (if necessary)
Block = NULL;
// This block is now the implicit successor of other blocks.
Succ = DefaultCaseBlock;
return DefaultCaseBlock;
}
CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
// "try"/"catch" is a control-flow statement. Thus we stop processing the
// current block.
CFGBlock *TrySuccessor = NULL;
if (Block) {
if (badCFG)
return 0;
TrySuccessor = Block;
} else TrySuccessor = Succ;
CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
// Create a new block that will contain the try statement.
CFGBlock *NewTryTerminatedBlock = createBlock(false);
// Add the terminator in the try block.
NewTryTerminatedBlock->setTerminator(Terminator);
bool HasCatchAll = false;
for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
// The code after the try is the implicit successor.
Succ = TrySuccessor;
CXXCatchStmt *CS = Terminator->getHandler(h);
if (CS->getExceptionDecl() == 0) {
HasCatchAll = true;
}
Block = NULL;
CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
if (CatchBlock == 0)
return 0;
// Add this block to the list of successors for the block with the try
// statement.
addSuccessor(NewTryTerminatedBlock, CatchBlock);
}
if (!HasCatchAll) {
if (PrevTryTerminatedBlock)
addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
else
addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
}
// The code after the try is the implicit successor.
Succ = TrySuccessor;
// Save the current "try" context.
SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
cfg->addTryDispatchBlock(TryTerminatedBlock);
assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
Block = NULL;
return addStmt(Terminator->getTryBlock());
}
CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
// CXXCatchStmt are treated like labels, so they are the first statement in a
// block.
// Save local scope position because in case of exception variable ScopePos
// won't be restored when traversing AST.
SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
// Create local scope for possible exception variable.
// Store scope position. Add implicit destructor.
if (VarDecl *VD = CS->getExceptionDecl()) {
LocalScope::const_iterator BeginScopePos = ScopePos;
addLocalScopeForVarDecl(VD);
addAutomaticObjDtors(ScopePos, BeginScopePos, CS);
}
if (CS->getHandlerBlock())
addStmt(CS->getHandlerBlock());
CFGBlock *CatchBlock = Block;
if (!CatchBlock)
CatchBlock = createBlock();
// CXXCatchStmt is more than just a label. They have semantic meaning
// as well, as they implicitly "initialize" the catch variable. Add
// it to the CFG as a CFGElement so that the control-flow of these
// semantics gets captured.
appendStmt(CatchBlock, CS);
// Also add the CXXCatchStmt as a label, to mirror handling of regular
// labels.
CatchBlock->setLabel(CS);
// Bail out if the CFG is bad.
if (badCFG)
return 0;
// We set Block to NULL to allow lazy creation of a new block (if necessary)
Block = NULL;
return CatchBlock;
}
CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
// C++0x for-range statements are specified as [stmt.ranged]:
//
// {
// auto && __range = range-init;
// for ( auto __begin = begin-expr,
// __end = end-expr;
// __begin != __end;
// ++__begin ) {
// for-range-declaration = *__begin;
// statement
// }
// }
// Save local scope position before the addition of the implicit variables.
SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
// Create local scopes and destructors for range, begin and end variables.
if (Stmt *Range = S->getRangeStmt())
addLocalScopeForStmt(Range);
if (Stmt *BeginEnd = S->getBeginEndStmt())
addLocalScopeForStmt(BeginEnd);
addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S);
LocalScope::const_iterator ContinueScopePos = ScopePos;
// "for" is a control-flow statement. Thus we stop processing the current
// block.
CFGBlock *LoopSuccessor = NULL;
if (Block) {
if (badCFG)
return 0;
LoopSuccessor = Block;
} else
LoopSuccessor = Succ;
// Save the current value for the break targets.
// All breaks should go to the code following the loop.
SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
// The block for the __begin != __end expression.
CFGBlock *ConditionBlock = createBlock(false);
ConditionBlock->setTerminator(S);
// Now add the actual condition to the condition block.
if (Expr *C = S->getCond()) {
Block = ConditionBlock;
CFGBlock *BeginConditionBlock = addStmt(C);
if (badCFG)
return 0;
assert(BeginConditionBlock == ConditionBlock &&
"condition block in for-range was unexpectedly complex");
(void)BeginConditionBlock;
}
// The condition block is the implicit successor for the loop body as well as
// any code above the loop.
Succ = ConditionBlock;
// See if this is a known constant.
TryResult KnownVal(true);
if (S->getCond())
KnownVal = tryEvaluateBool(S->getCond());
// Now create the loop body.
{
assert(S->getBody());
// Save the current values for Block, Succ, and continue targets.
SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
// Generate increment code in its own basic block. This is the target of
// continue statements.
Block = 0;
Succ = addStmt(S->getInc());
ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
// The starting block for the loop increment is the block that should
// represent the 'loop target' for looping back to the start of the loop.
ContinueJumpTarget.block->setLoopTarget(S);
// Finish up the increment block and prepare to start the loop body.
assert(Block);
if (badCFG)
return 0;
Block = 0;
// Add implicit scope and dtors for loop variable.
addLocalScopeAndDtors(S->getLoopVarStmt());
// Populate a new block to contain the loop body and loop variable.
addStmt(S->getBody());
if (badCFG)
return 0;
CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
if (badCFG)
return 0;
// This new body block is a successor to our condition block.
addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : LoopVarStmtBlock);
}
// Link up the condition block with the code that follows the loop (the
// false branch).
addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor);
// Add the initialization statements.
Block = createBlock();
addStmt(S->getBeginEndStmt());
return addStmt(S->getRangeStmt());
}
CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
AddStmtChoice asc) {
if (BuildOpts.AddTemporaryDtors) {
// If adding implicit destructors visit the full expression for adding
// destructors of temporaries.
VisitForTemporaryDtors(E->getSubExpr());
// Full expression has to be added as CFGStmt so it will be sequenced
// before destructors of it's temporaries.
asc = asc.withAlwaysAdd(true);
}
return Visit(E->getSubExpr(), asc);
}
CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
AddStmtChoice asc) {
if (asc.alwaysAdd(*this, E)) {
autoCreateBlock();
appendStmt(Block, E);
// We do not want to propagate the AlwaysAdd property.
asc = asc.withAlwaysAdd(false);
}
return Visit(E->getSubExpr(), asc);
}
CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
AddStmtChoice asc) {
autoCreateBlock();
appendStmt(Block, C);
return VisitChildren(C);
}
CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
AddStmtChoice asc) {
if (asc.alwaysAdd(*this, E)) {
autoCreateBlock();
appendStmt(Block, E);
// We do not want to propagate the AlwaysAdd property.
asc = asc.withAlwaysAdd(false);
}
return Visit(E->getSubExpr(), asc);
}
CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
AddStmtChoice asc) {
autoCreateBlock();
appendStmt(Block, C);
return VisitChildren(C);
}
CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
AddStmtChoice asc) {
if (asc.alwaysAdd(*this, E)) {
autoCreateBlock();
appendStmt(Block, E);
}
return Visit(E->getSubExpr(), AddStmtChoice());
}
CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
// Lazily create the indirect-goto dispatch block if there isn't one already.
CFGBlock *IBlock = cfg->getIndirectGotoBlock();
if (!IBlock) {
IBlock = createBlock(false);
cfg->setIndirectGotoBlock(IBlock);
}
// IndirectGoto is a control-flow statement. Thus we stop processing the
// current block and create a new one.
if (badCFG)
return 0;
Block = createBlock(false);
Block->setTerminator(I);
addSuccessor(Block, IBlock);
return addStmt(I->getTarget());
}
CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) {
assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
tryAgain:
if (!E) {
badCFG = true;
return NULL;
}
switch (E->getStmtClass()) {
default:
return VisitChildrenForTemporaryDtors(E);
case Stmt::BinaryOperatorClass:
return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E));
case Stmt::CXXBindTemporaryExprClass:
return VisitCXXBindTemporaryExprForTemporaryDtors(
cast<CXXBindTemporaryExpr>(E), BindToTemporary);
case Stmt::BinaryConditionalOperatorClass:
case Stmt::ConditionalOperatorClass:
return VisitConditionalOperatorForTemporaryDtors(
cast<AbstractConditionalOperator>(E), BindToTemporary);
case Stmt::ImplicitCastExprClass:
// For implicit cast we want BindToTemporary to be passed further.
E = cast<CastExpr>(E)->getSubExpr();
goto tryAgain;
case Stmt::ParenExprClass:
E = cast<ParenExpr>(E)->getSubExpr();
goto tryAgain;
case Stmt::MaterializeTemporaryExprClass:
E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr();
goto tryAgain;
}
}
CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) {
// When visiting children for destructors we want to visit them in reverse
// order. Because there's no reverse iterator for children must to reverse
// them in helper vector.
typedef SmallVector<Stmt *, 4> ChildrenVect;
ChildrenVect ChildrenRev;
for (Stmt::child_range I = E->children(); I; ++I) {
if (*I) ChildrenRev.push_back(*I);
}
CFGBlock *B = Block;
for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(),
L = ChildrenRev.rend(); I != L; ++I) {
if (CFGBlock *R = VisitForTemporaryDtors(*I))
B = R;
}
return B;
}
CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) {
if (E->isLogicalOp()) {
// Destructors for temporaries in LHS expression should be called after
// those for RHS expression. Even if this will unnecessarily create a block,
// this block will be used at least by the full expression.
autoCreateBlock();
CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS());
if (badCFG)
return NULL;
Succ = ConfluenceBlock;
Block = NULL;
CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
if (RHSBlock) {
if (badCFG)
return NULL;
// If RHS expression did produce destructors we need to connect created
// blocks to CFG in same manner as for binary operator itself.
CFGBlock *LHSBlock = createBlock(false);
LHSBlock->setTerminator(CFGTerminator(E, true));
// For binary operator LHS block is before RHS in list of predecessors
// of ConfluenceBlock.
std::reverse(ConfluenceBlock->pred_begin(),
ConfluenceBlock->pred_end());
// See if this is a known constant.
TryResult KnownVal = tryEvaluateBool(E->getLHS());
if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr))
KnownVal.negate();
// Link LHSBlock with RHSBlock exactly the same way as for binary operator
// itself.
if (E->getOpcode() == BO_LOr) {
addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock);
addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
} else {
assert (E->getOpcode() == BO_LAnd);
addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock);
}
Block = LHSBlock;
return LHSBlock;
}
Block = ConfluenceBlock;
return ConfluenceBlock;
}
if (E->isAssignmentOp()) {
// For assignment operator (=) LHS expression is visited
// before RHS expression. For destructors visit them in reverse order.
CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS());
return LHSBlock ? LHSBlock : RHSBlock;
}
// For any other binary operator RHS expression is visited before
// LHS expression (order of children). For destructors visit them in reverse
// order.
CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS());
CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
return RHSBlock ? RHSBlock : LHSBlock;
}
CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
CXXBindTemporaryExpr *E, bool BindToTemporary) {
// First add destructors for temporaries in subexpression.
CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr());
if (!BindToTemporary) {
// If lifetime of temporary is not prolonged (by assigning to constant
// reference) add destructor for it.
// If the destructor is marked as a no-return destructor, we need to create
// a new block for the destructor which does not have as a successor
// anything built thus far. Control won't flow out of this block.
const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
if (Dtor->isNoReturn())
Block = createNoReturnBlock();
else
autoCreateBlock();
appendTemporaryDtor(Block, E);
B = Block;
}
return B;
}
CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
AbstractConditionalOperator *E, bool BindToTemporary) {
// First add destructors for condition expression. Even if this will
// unnecessarily create a block, this block will be used at least by the full
// expression.
autoCreateBlock();
CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond());
if (badCFG)
return NULL;
if (BinaryConditionalOperator *BCO
= dyn_cast<BinaryConditionalOperator>(E)) {
ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon());
if (badCFG)
return NULL;
}
// Try to add block with destructors for LHS expression.
CFGBlock *LHSBlock = NULL;
Succ = ConfluenceBlock;
Block = NULL;
LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary);
if (badCFG)
return NULL;
// Try to add block with destructors for RHS expression;
Succ = ConfluenceBlock;
Block = NULL;
CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(),
BindToTemporary);
if (badCFG)
return NULL;
if (!RHSBlock && !LHSBlock) {
// If neither LHS nor RHS expression had temporaries to destroy don't create
// more blocks.
Block = ConfluenceBlock;
return Block;
}
Block = createBlock(false);
Block->setTerminator(CFGTerminator(E, true));
// See if this is a known constant.
const TryResult &KnownVal = tryEvaluateBool(E->getCond());
if (LHSBlock) {
addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
} else if (KnownVal.isFalse()) {
addSuccessor(Block, NULL);
} else {
addSuccessor(Block, ConfluenceBlock);
std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end());
}
if (!RHSBlock)
RHSBlock = ConfluenceBlock;
addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
return Block;
}
} // end anonymous namespace
/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
/// no successors or predecessors. If this is the first block created in the
/// CFG, it is automatically set to be the Entry and Exit of the CFG.
CFGBlock *CFG::createBlock() {
bool first_block = begin() == end();
// Create the block.
CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
Blocks.push_back(Mem, BlkBVC);
// If this is the first block, set it as the Entry and Exit.
if (first_block)
Entry = Exit = &back();
// Return the block.
return &back();
}
/// buildCFG - Constructs a CFG from an AST. Ownership of the returned
/// CFG is returned to the caller.
CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C,
const BuildOptions &BO) {
CFGBuilder Builder(C, BO);
return Builder.buildCFG(D, Statement);
}
const CXXDestructorDecl *
CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const {
switch (getKind()) {
case CFGElement::Invalid:
case CFGElement::Statement:
case CFGElement::Initializer:
llvm_unreachable("getDestructorDecl should only be used with "
"ImplicitDtors");
case CFGElement::AutomaticObjectDtor: {
const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl();
QualType ty = var->getType();
ty = ty.getNonReferenceType();
while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
ty = arrayType->getElementType();
}
const RecordType *recordType = ty->getAs<RecordType>();
const CXXRecordDecl *classDecl =
cast<CXXRecordDecl>(recordType->getDecl());
return classDecl->getDestructor();
}
case CFGElement::TemporaryDtor: {
const CXXBindTemporaryExpr *bindExpr =
cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr();
const CXXTemporary *temp = bindExpr->getTemporary();
return temp->getDestructor();
}
case CFGElement::BaseDtor:
case CFGElement::MemberDtor:
// Not yet supported.
return 0;
}
llvm_unreachable("getKind() returned bogus value");
}
bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
return DD->isNoReturn();
return false;
}
//===----------------------------------------------------------------------===//
// CFG: Queries for BlkExprs.
//===----------------------------------------------------------------------===//
namespace {
typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy;
}
static void FindSubExprAssignments(const Stmt *S,
llvm::SmallPtrSet<const Expr*,50>& Set) {
if (!S)
return;
for (Stmt::const_child_range I = S->children(); I; ++I) {
const Stmt *child = *I;
if (!child)
continue;
if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child))
if (B->isAssignmentOp()) Set.insert(B);
FindSubExprAssignments(child, Set);
}
}
static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) {
BlkExprMapTy* M = new BlkExprMapTy();
// Look for assignments that are used as subexpressions. These are the only
// assignments that we want to *possibly* register as a block-level
// expression. Basically, if an assignment occurs both in a subexpression and
// at the block-level, it is a block-level expression.
llvm::SmallPtrSet<const Expr*,50> SubExprAssignments;
for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I)
for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI)
if (const CFGStmt *S = BI->getAs<CFGStmt>())
FindSubExprAssignments(S->getStmt(), SubExprAssignments);
for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) {
// Iterate over the statements again on identify the Expr* and Stmt* at the
// block-level that are block-level expressions.
for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) {
const CFGStmt *CS = BI->getAs<CFGStmt>();
if (!CS)
continue;
if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) {
assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps");
if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) {
// Assignment expressions that are not nested within another
// expression are really "statements" whose value is never used by
// another expression.
if (B->isAssignmentOp() && !SubExprAssignments.count(Exp))
continue;
} else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) {
// Special handling for statement expressions. The last statement in
// the statement expression is also a block-level expr.
const CompoundStmt *C = SE->getSubStmt();
if (!C->body_empty()) {
const Stmt *Last = C->body_back();
if (const Expr *LastEx = dyn_cast<Expr>(Last))
Last = LastEx->IgnoreParens();
unsigned x = M->size();
(*M)[Last] = x;
}
}
unsigned x = M->size();
(*M)[Exp] = x;
}
}
// Look at terminators. The condition is a block-level expression.
Stmt *S = (*I)->getTerminatorCondition();
if (S && M->find(S) == M->end()) {
unsigned x = M->size();
(*M)[S] = x;
}
}
return M;
}
CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) {
assert(S != NULL);
if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); }
BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap);
BlkExprMapTy::iterator I = M->find(S);
return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second);
}
unsigned CFG::getNumBlkExprs() {
if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap))
return M->size();
// We assume callers interested in the number of BlkExprs will want
// the map constructed if it doesn't already exist.
BlkExprMap = (void*) PopulateBlkExprMap(*this);
return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size();
}
//===----------------------------------------------------------------------===//
// Filtered walking of the CFG.
//===----------------------------------------------------------------------===//
bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F,
const CFGBlock *From, const CFGBlock *To) {
if (To && F.IgnoreDefaultsWithCoveredEnums) {
// If the 'To' has no label or is labeled but the label isn't a
// CaseStmt then filter this edge.
if (const SwitchStmt *S =
dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
if (S->isAllEnumCasesCovered()) {
const Stmt *L = To->getLabel();
if (!L || !isa<CaseStmt>(L))
return true;
}
}
}
return false;
}
//===----------------------------------------------------------------------===//
// Cleanup: CFG dstor.
//===----------------------------------------------------------------------===//
CFG::~CFG() {
delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap);
}
//===----------------------------------------------------------------------===//
// CFG pretty printing
//===----------------------------------------------------------------------===//
namespace {
class StmtPrinterHelper : public PrinterHelper {
typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy;
typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy;
StmtMapTy StmtMap;
DeclMapTy DeclMap;
signed currentBlock;
unsigned currStmt;
const LangOptions &LangOpts;
public:
StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
: currentBlock(0), currStmt(0), LangOpts(LO)
{
for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
unsigned j = 1;
for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
BI != BEnd; ++BI, ++j ) {
if (const CFGStmt *SE = BI->getAs<CFGStmt>()) {
const Stmt *stmt= SE->getStmt();
std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
StmtMap[stmt] = P;
switch (stmt->getStmtClass()) {
case Stmt::DeclStmtClass:
DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
break;
case Stmt::IfStmtClass: {
const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
if (var)
DeclMap[var] = P;
break;
}
case Stmt::ForStmtClass: {
const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
if (var)
DeclMap[var] = P;
break;
}
case Stmt::WhileStmtClass: {
const VarDecl *var =
cast<WhileStmt>(stmt)->getConditionVariable();
if (var)
DeclMap[var] = P;
break;
}
case Stmt::SwitchStmtClass: {
const VarDecl *var =
cast<SwitchStmt>(stmt)->getConditionVariable();
if (var)
DeclMap[var] = P;
break;
}
case Stmt::CXXCatchStmtClass: {
const VarDecl *var =
cast<CXXCatchStmt>(stmt)->getExceptionDecl();
if (var)
DeclMap[var] = P;
break;
}
default:
break;
}
}
}
}
}
virtual ~StmtPrinterHelper() {}
const LangOptions &getLangOpts() const { return LangOpts; }
void setBlockID(signed i) { currentBlock = i; }
void setStmtID(unsigned i) { currStmt = i; }
virtual bool handledStmt(Stmt *S, raw_ostream &OS) {
StmtMapTy::iterator I = StmtMap.find(S);
if (I == StmtMap.end())
return false;
if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
&& I->second.second == currStmt) {
return false;
}
OS << "[B" << I->second.first << "." << I->second.second << "]";
return true;
}
bool handleDecl(const Decl *D, raw_ostream &OS) {
DeclMapTy::iterator I = DeclMap.find(D);
if (I == DeclMap.end())
return false;
if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
&& I->second.second == currStmt) {
return false;
}
OS << "[B" << I->second.first << "." << I->second.second << "]";
return true;
}
};
} // end anonymous namespace
namespace {
class CFGBlockTerminatorPrint
: public StmtVisitor<CFGBlockTerminatorPrint,void> {
raw_ostream &OS;
StmtPrinterHelper* Helper;
PrintingPolicy Policy;
public:
CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
const PrintingPolicy &Policy)
: OS(os), Helper(helper), Policy(Policy) {}
void VisitIfStmt(IfStmt *I) {
OS << "if ";
I->getCond()->printPretty(OS,Helper,Policy);
}
// Default case.
void VisitStmt(Stmt *Terminator) {
Terminator->printPretty(OS, Helper, Policy);
}
void VisitForStmt(ForStmt *F) {
OS << "for (" ;
if (F->getInit())
OS << "...";
OS << "; ";
if (Stmt *C = F->getCond())
C->printPretty(OS, Helper, Policy);
OS << "; ";
if (F->getInc())
OS << "...";
OS << ")";
}
void VisitWhileStmt(WhileStmt *W) {
OS << "while " ;
if (Stmt *C = W->getCond())
C->printPretty(OS, Helper, Policy);
}
void VisitDoStmt(DoStmt *D) {
OS << "do ... while ";
if (Stmt *C = D->getCond())
C->printPretty(OS, Helper, Policy);
}
void VisitSwitchStmt(SwitchStmt *Terminator) {
OS << "switch ";
Terminator->getCond()->printPretty(OS, Helper, Policy);
}
void VisitCXXTryStmt(CXXTryStmt *CS) {
OS << "try ...";
}
void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
C->getCond()->printPretty(OS, Helper, Policy);
OS << " ? ... : ...";
}
void VisitChooseExpr(ChooseExpr *C) {
OS << "__builtin_choose_expr( ";
C->getCond()->printPretty(OS, Helper, Policy);
OS << " )";
}
void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
OS << "goto *";
I->getTarget()->printPretty(OS, Helper, Policy);
}
void VisitBinaryOperator(BinaryOperator* B) {
if (!B->isLogicalOp()) {
VisitExpr(B);
return;
}
B->getLHS()->printPretty(OS, Helper, Policy);
switch (B->getOpcode()) {
case BO_LOr:
OS << " || ...";
return;
case BO_LAnd:
OS << " && ...";
return;
default:
llvm_unreachable("Invalid logical operator.");
}
}
void VisitExpr(Expr *E) {
E->printPretty(OS, Helper, Policy);
}
};
} // end anonymous namespace
static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper,
const CFGElement &E) {
if (const CFGStmt *CS = E.getAs<CFGStmt>()) {
const Stmt *S = CS->getStmt();
if (Helper) {
// special printing for statement-expressions.
if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
const CompoundStmt *Sub = SE->getSubStmt();
if (Sub->children()) {
OS << "({ ... ; ";
Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
OS << " })\n";
return;
}
}
// special printing for comma expressions.
if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
if (B->getOpcode() == BO_Comma) {
OS << "... , ";
Helper->handledStmt(B->getRHS(),OS);
OS << '\n';
return;
}
}
}
S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts()));
if (isa<CXXOperatorCallExpr>(S)) {
OS << " (OperatorCall)";
}
else if (isa<CXXBindTemporaryExpr>(S)) {
OS << " (BindTemporary)";
}
else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")";
}
else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
OS << " (" << CE->getStmtClassName() << ", "
<< CE->getCastKindName()
<< ", " << CE->getType().getAsString()
<< ")";
}
// Expressions need a newline.
if (isa<Expr>(S))
OS << '\n';
} else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) {
const CXXCtorInitializer *I = IE->getInitializer();
if (I->isBaseInitializer())
OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
else OS << I->getAnyMember()->getName();
OS << "(";
if (Expr *IE = I->getInit())
IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts()));
OS << ")";
if (I->isBaseInitializer())
OS << " (Base initializer)\n";
else OS << " (Member initializer)\n";
} else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){
const VarDecl *VD = DE->getVarDecl();
Helper->handleDecl(VD, OS);
const Type* T = VD->getType().getTypePtr();
if (const ReferenceType* RT = T->getAs<ReferenceType>())
T = RT->getPointeeType().getTypePtr();
T = T->getBaseElementTypeUnsafe();
OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
OS << " (Implicit destructor)\n";
} else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) {
const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
OS << " (Base object destructor)\n";
} else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) {
const FieldDecl *FD = ME->getFieldDecl();
const Type *T = FD->getType()->getBaseElementTypeUnsafe();
OS << "this->" << FD->getName();
OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
OS << " (Member object destructor)\n";
} else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) {
const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()";
OS << " (Temporary object destructor)\n";
}
}
static void print_block(raw_ostream &OS, const CFG* cfg,
const CFGBlock &B,
StmtPrinterHelper* Helper, bool print_edges,
bool ShowColors) {
if (Helper)
Helper->setBlockID(B.getBlockID());
// Print the header.
if (ShowColors)
OS.changeColor(raw_ostream::YELLOW, true);
OS << "\n [B" << B.getBlockID();
if (&B == &cfg->getEntry())
OS << " (ENTRY)]\n";
else if (&B == &cfg->getExit())
OS << " (EXIT)]\n";
else if (&B == cfg->getIndirectGotoBlock())
OS << " (INDIRECT GOTO DISPATCH)]\n";
else
OS << "]\n";
if (ShowColors)
OS.resetColor();
// Print the label of this block.
if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
if (print_edges)
OS << " ";
if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
OS << L->getName();
else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
OS << "case ";
C->getLHS()->printPretty(OS, Helper,
PrintingPolicy(Helper->getLangOpts()));
if (C->getRHS()) {
OS << " ... ";
C->getRHS()->printPretty(OS, Helper,
PrintingPolicy(Helper->getLangOpts()));
}
} else if (isa<DefaultStmt>(Label))
OS << "default";
else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
OS << "catch (";
if (CS->getExceptionDecl())
CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()),
0);
else
OS << "...";
OS << ")";
} else
llvm_unreachable("Invalid label statement in CFGBlock.");
OS << ":\n";
}
// Iterate through the statements in the block and print them.
unsigned j = 1;
for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
I != E ; ++I, ++j ) {
// Print the statement # in the basic block and the statement itself.
if (print_edges)
OS << " ";
OS << llvm::format("%3d", j) << ": ";
if (Helper)
Helper->setStmtID(j);
print_elem(OS, Helper, *I);
}
// Print the terminator of this block.
if (B.getTerminator()) {
if (ShowColors)
OS.changeColor(raw_ostream::GREEN);
OS << " T: ";
if (Helper) Helper->setBlockID(-1);
PrintingPolicy PP(Helper ? Helper->getLangOpts() : LangOptions());
CFGBlockTerminatorPrint TPrinter(OS, Helper, PP);
TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt()));
OS << '\n';
if (ShowColors)
OS.resetColor();
}
if (print_edges) {
// Print the predecessors of this block.
if (!B.pred_empty()) {
const raw_ostream::Colors Color = raw_ostream::BLUE;
if (ShowColors)
OS.changeColor(Color);
OS << " Preds " ;
if (ShowColors)
OS.resetColor();
OS << '(' << B.pred_size() << "):";
unsigned i = 0;
if (ShowColors)
OS.changeColor(Color);
for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
I != E; ++I, ++i) {
if (i % 10 == 8)
OS << "\n ";
OS << " B" << (*I)->getBlockID();
}
if (ShowColors)
OS.resetColor();
OS << '\n';
}
// Print the successors of this block.
if (!B.succ_empty()) {
const raw_ostream::Colors Color = raw_ostream::MAGENTA;
if (ShowColors)
OS.changeColor(Color);
OS << " Succs ";
if (ShowColors)
OS.resetColor();
OS << '(' << B.succ_size() << "):";
unsigned i = 0;
if (ShowColors)
OS.changeColor(Color);
for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
I != E; ++I, ++i) {
if (i % 10 == 8)
OS << "\n ";
if (*I)
OS << " B" << (*I)->getBlockID();
else
OS << " NULL";
}
if (ShowColors)
OS.resetColor();
OS << '\n';
}
}
}
/// dump - A simple pretty printer of a CFG that outputs to stderr.
void CFG::dump(const LangOptions &LO, bool ShowColors) const {
print(llvm::errs(), LO, ShowColors);
}
/// print - A simple pretty printer of a CFG that outputs to an ostream.
void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
StmtPrinterHelper Helper(this, LO);
// Print the entry block.
print_block(OS, this, getEntry(), &Helper, true, ShowColors);
// Iterate through the CFGBlocks and print them one by one.
for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
// Skip the entry block, because we already printed it.
if (&(**I) == &getEntry() || &(**I) == &getExit())
continue;
print_block(OS, this, **I, &Helper, true, ShowColors);
}
// Print the exit block.
print_block(OS, this, getExit(), &Helper, true, ShowColors);
OS << '\n';
OS.flush();
}
/// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
bool ShowColors) const {
print(llvm::errs(), cfg, LO, ShowColors);
}
/// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
/// Generally this will only be called from CFG::print.
void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
const LangOptions &LO, bool ShowColors) const {
StmtPrinterHelper Helper(cfg, LO);
print_block(OS, cfg, *this, &Helper, true, ShowColors);
OS << '\n';
}
/// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
void CFGBlock::printTerminator(raw_ostream &OS,
const LangOptions &LO) const {
CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO));
TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt()));
}
Stmt *CFGBlock::getTerminatorCondition() {
Stmt *Terminator = this->Terminator;
if (!Terminator)
return NULL;
Expr *E = NULL;
switch (Terminator->getStmtClass()) {
default:
break;
case Stmt::ForStmtClass:
E = cast<ForStmt>(Terminator)->getCond();
break;
case Stmt::WhileStmtClass:
E = cast<WhileStmt>(Terminator)->getCond();
break;
case Stmt::DoStmtClass:
E = cast<DoStmt>(Terminator)->getCond();
break;
case Stmt::IfStmtClass:
E = cast<IfStmt>(Terminator)->getCond();
break;
case Stmt::ChooseExprClass:
E = cast<ChooseExpr>(Terminator)->getCond();
break;
case Stmt::IndirectGotoStmtClass:
E = cast<IndirectGotoStmt>(Terminator)->getTarget();
break;
case Stmt::SwitchStmtClass:
E = cast<SwitchStmt>(Terminator)->getCond();
break;
case Stmt::BinaryConditionalOperatorClass:
E = cast<BinaryConditionalOperator>(Terminator)->getCond();
break;
case Stmt::ConditionalOperatorClass:
E = cast<ConditionalOperator>(Terminator)->getCond();
break;
case Stmt::BinaryOperatorClass: // '&&' and '||'
E = cast<BinaryOperator>(Terminator)->getLHS();
break;
case Stmt::ObjCForCollectionStmtClass:
return Terminator;
}
return E ? E->IgnoreParens() : NULL;
}
//===----------------------------------------------------------------------===//
// CFG Graphviz Visualization
//===----------------------------------------------------------------------===//
#ifndef NDEBUG
static StmtPrinterHelper* GraphHelper;
#endif
void CFG::viewCFG(const LangOptions &LO) const {
#ifndef NDEBUG
StmtPrinterHelper H(this, LO);
GraphHelper = &H;
llvm::ViewGraph(this,"CFG");
GraphHelper = NULL;
#endif
}
namespace llvm {
template<>
struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
#ifndef NDEBUG
std::string OutSStr;
llvm::raw_string_ostream Out(OutSStr);
print_block(Out,Graph, *Node, GraphHelper, false, false);
std::string& OutStr = Out.str();
if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
// Process string output to make it nicer...
for (unsigned i = 0; i != OutStr.length(); ++i)
if (OutStr[i] == '\n') { // Left justify
OutStr[i] = '\\';
OutStr.insert(OutStr.begin()+i+1, 'l');
}
return OutStr;
#else
return "";
#endif
}
};
} // end namespace llvm