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clang-1/lib/AST/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/AST/CFG.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/AST/PrettyPrinter.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/Streams.h"
#include "llvm/Support/Compiler.h"
#include <llvm/Support/Allocator.h>
#include <iomanip>
#include <algorithm>
#include <sstream>
using namespace clang;
namespace {
// SaveAndRestore - A utility class that uses RIIA to save and restore
// the value of a variable.
template<typename T>
struct VISIBILITY_HIDDEN SaveAndRestore {
SaveAndRestore(T& x) : X(x), old_value(x) {}
~SaveAndRestore() { X = old_value; }
T get() { return old_value; }
T& X;
T old_value;
};
static SourceLocation GetEndLoc(ScopedDecl* D) {
if (VarDecl* VD = dyn_cast<VarDecl>(D))
if (Expr* Ex = VD->getInit())
return Ex->getSourceRange().getEnd();
return D->getLocation();
}
class VISIBILITY_HIDDEN UnaryDeclStmt : public DeclStmt {
Stmt* Ex;
public:
UnaryDeclStmt(ScopedDecl* D)
: DeclStmt(D, D->getLocation(), GetEndLoc(D)), Ex(0) {
if (VarDecl* VD = dyn_cast<VarDecl>(D))
Ex = VD->getInit();
}
virtual ~UnaryDeclStmt() {}
virtual void Destroy(ASTContext& Ctx) { assert(false && "Do not call"); }
virtual child_iterator child_begin() {
return Ex ? &Ex : 0;
}
virtual child_iterator child_end() {
return Ex ? &Ex + 1 : 0;
}
virtual decl_iterator decl_begin() {
return getDecl();
}
virtual decl_iterator decl_end() {
ScopedDecl* D = getDecl();
return D ? D->getNextDeclarator() : 0;
}
};
/// 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 VISIBILITY_HIDDEN CFGBuilder : public StmtVisitor<CFGBuilder,CFGBlock*> {
CFG* cfg;
CFGBlock* Block;
CFGBlock* Succ;
CFGBlock* ContinueTargetBlock;
CFGBlock* BreakTargetBlock;
CFGBlock* SwitchTerminatedBlock;
CFGBlock* DefaultCaseBlock;
// LabelMap records the mapping from Label expressions to their blocks.
typedef llvm::DenseMap<LabelStmt*,CFGBlock*> 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<CFGBlock*> BackpatchBlocksTy;
BackpatchBlocksTy BackpatchBlocks;
// A list of labels whose address has been taken (for indirect gotos).
typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy;
LabelSetTy AddressTakenLabels;
public:
explicit CFGBuilder() : cfg(NULL), Block(NULL), Succ(NULL),
ContinueTargetBlock(NULL), BreakTargetBlock(NULL),
SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL) {
// Create an empty CFG.
cfg = new CFG();
}
~CFGBuilder() { delete cfg; }
// buildCFG - Used by external clients to construct the CFG.
CFG* buildCFG(Stmt* Statement);
// Visitors to walk an AST and construct the CFG. Called by
// buildCFG. Do not call directly!
CFGBlock* VisitStmt(Stmt* Statement);
CFGBlock* VisitNullStmt(NullStmt* Statement);
CFGBlock* VisitCompoundStmt(CompoundStmt* C);
CFGBlock* VisitIfStmt(IfStmt* I);
CFGBlock* VisitReturnStmt(ReturnStmt* R);
CFGBlock* VisitLabelStmt(LabelStmt* L);
CFGBlock* VisitGotoStmt(GotoStmt* G);
CFGBlock* VisitForStmt(ForStmt* F);
CFGBlock* VisitWhileStmt(WhileStmt* W);
CFGBlock* VisitDoStmt(DoStmt* D);
CFGBlock* VisitContinueStmt(ContinueStmt* C);
CFGBlock* VisitBreakStmt(BreakStmt* B);
CFGBlock* VisitSwitchStmt(SwitchStmt* Terminator);
CFGBlock* VisitCaseStmt(CaseStmt* Terminator);
CFGBlock* VisitDefaultStmt(DefaultStmt* D);
CFGBlock* VisitIndirectGotoStmt(IndirectGotoStmt* I);
// FIXME: Add support for ObjC-specific control-flow structures.
// NYS == Not Yet Supported
CFGBlock* NYS() {
badCFG = true;
return Block;
}
CFGBlock* VisitObjCForCollectionStmt(ObjCForCollectionStmt* S){ return NYS();}
CFGBlock* VisitObjCAtTryStmt(ObjCAtTryStmt* S) { return NYS(); }
CFGBlock* VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { return NYS(); }
CFGBlock* VisitObjCAtFinallyStmt(ObjCAtFinallyStmt* S) { return NYS(); }
CFGBlock* VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { return NYS(); }
CFGBlock* VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S){
return NYS();
}
private:
CFGBlock* createBlock(bool add_successor = true);
CFGBlock* addStmt(Stmt* Terminator);
CFGBlock* WalkAST(Stmt* Terminator, bool AlwaysAddStmt);
CFGBlock* WalkAST_VisitChildren(Stmt* Terminator);
CFGBlock* WalkAST_VisitDeclSubExpr(ScopedDecl* D);
CFGBlock* WalkAST_VisitStmtExpr(StmtExpr* Terminator);
void FinishBlock(CFGBlock* B);
bool badCFG;
};
/// 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(Stmt* Statement) {
assert (cfg);
if (!Statement) return NULL;
badCFG = false;
// 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.
// Visit the statements and create the CFG.
CFGBlock* B = Visit(Statement);
if (!B) B = Succ;
if (B) {
// Finalize the last constructed block. This usually involves
// reversing the order of the statements in the block.
if (Block) FinishBlock(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;
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;
B->addSuccessor(LI->second);
}
// 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;
B->addSuccessor(LI->second);
}
Succ = B;
}
// Create an empty entry block that has no predecessors.
cfg->setEntry(createBlock());
if (badCFG) {
delete cfg;
cfg = NULL;
return NULL;
}
// NULL out cfg so that repeated calls to the builder will fail and that
// the ownership of the constructed CFG is passed to the caller.
CFG* t = cfg;
cfg = NULL;
return t;
}
/// 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) B->addSuccessor(Succ);
return B;
}
/// FinishBlock - When the last statement has been added to the block,
/// we must reverse the statements because they have been inserted
/// in reverse order.
void CFGBuilder::FinishBlock(CFGBlock* B) {
assert (B);
B->reverseStmts();
}
/// addStmt - Used to add statements/expressions to the current CFGBlock
/// "Block". This method calls WalkAST on the passed statement to see if it
/// contains any short-circuit expressions. If so, it recursively creates
/// the necessary blocks for such expressions. It returns the "topmost" block
/// of the created blocks, or the original value of "Block" when this method
/// was called if no additional blocks are created.
CFGBlock* CFGBuilder::addStmt(Stmt* Terminator) {
if (!Block) Block = createBlock();
return WalkAST(Terminator,true);
}
/// WalkAST - Used by addStmt to 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::WalkAST(Stmt* Terminator, bool AlwaysAddStmt = false) {
switch (Terminator->getStmtClass()) {
case Stmt::ConditionalOperatorClass: {
ConditionalOperator* C = cast<ConditionalOperator>(Terminator);
// Create the confluence block that will "merge" the results
// of the ternary expression.
CFGBlock* ConfluenceBlock = (Block) ? Block : createBlock();
ConfluenceBlock->appendStmt(C);
FinishBlock(ConfluenceBlock);
// 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 = NULL;
if (C->getLHS()) {
LHSBlock = Visit(C->getLHS());
FinishBlock(LHSBlock);
Block = NULL;
}
// Create the block for the RHS expression.
Succ = ConfluenceBlock;
CFGBlock* RHSBlock = Visit(C->getRHS());
FinishBlock(RHSBlock);
// Create the block that will contain the condition.
Block = createBlock(false);
if (LHSBlock)
Block->addSuccessor(LHSBlock);
else {
// If we have no LHS expression, add the ConfluenceBlock as a direct
// successor for the block containing the condition. Moreover,
// we need to reverse the order of the predecessors in the
// ConfluenceBlock because the RHSBlock will have been added to
// the succcessors already, and we want the first predecessor to the
// the block containing the expression for the case when the ternary
// expression evaluates to true.
Block->addSuccessor(ConfluenceBlock);
assert (ConfluenceBlock->pred_size() == 2);
std::reverse(ConfluenceBlock->pred_begin(),
ConfluenceBlock->pred_end());
}
Block->addSuccessor(RHSBlock);
Block->setTerminator(C);
return addStmt(C->getCond());
}
case Stmt::ChooseExprClass: {
ChooseExpr* C = cast<ChooseExpr>(Terminator);
CFGBlock* ConfluenceBlock = (Block) ? Block : createBlock();
ConfluenceBlock->appendStmt(C);
FinishBlock(ConfluenceBlock);
Succ = ConfluenceBlock;
Block = NULL;
CFGBlock* LHSBlock = Visit(C->getLHS());
FinishBlock(LHSBlock);
Succ = ConfluenceBlock;
Block = NULL;
CFGBlock* RHSBlock = Visit(C->getRHS());
FinishBlock(RHSBlock);
Block = createBlock(false);
Block->addSuccessor(LHSBlock);
Block->addSuccessor(RHSBlock);
Block->setTerminator(C);
return addStmt(C->getCond());
}
case Stmt::DeclStmtClass: {
ScopedDecl* D = cast<DeclStmt>(Terminator)->getDecl();
if (!D->getNextDeclarator()) {
Block->appendStmt(Terminator);
return WalkAST_VisitDeclSubExpr(D);
}
else {
typedef llvm::SmallVector<ScopedDecl*,10> BufTy;
BufTy Buf;
CFGBlock* B = 0;
do { Buf.push_back(D); D = D->getNextDeclarator(); } while (D);
for (BufTy::reverse_iterator I=Buf.rbegin(), E=Buf.rend(); I!=E; ++I) {
// Get the alignment of UnaryDeclStmt, padding out to >=8 bytes.
unsigned A = llvm::AlignOf<UnaryDeclStmt>::Alignment < 8
? 8 : llvm::AlignOf<UnaryDeclStmt>::Alignment;
// Allocate the UnaryDeclStmt using the BumpPtrAllocator. It will
// get automatically freed with the CFG.
void* Mem = cfg->getAllocator().Allocate(sizeof(UnaryDeclStmt), A);
// Append the fake DeclStmt to block.
Block->appendStmt(new (Mem) UnaryDeclStmt(*I));
B = WalkAST_VisitDeclSubExpr(*I);
}
return B;
}
}
case Stmt::AddrLabelExprClass: {
AddrLabelExpr* A = cast<AddrLabelExpr>(Terminator);
AddressTakenLabels.insert(A->getLabel());
if (AlwaysAddStmt) Block->appendStmt(Terminator);
return Block;
}
case Stmt::StmtExprClass:
return WalkAST_VisitStmtExpr(cast<StmtExpr>(Terminator));
case Stmt::UnaryOperatorClass: {
UnaryOperator* U = cast<UnaryOperator>(Terminator);
// sizeof(expressions). For such expressions,
// the subexpression is not really evaluated, so
// we don't care about control-flow within the sizeof.
if (U->getOpcode() == UnaryOperator::SizeOf) {
Block->appendStmt(Terminator);
return Block;
}
break;
}
case Stmt::BinaryOperatorClass: {
BinaryOperator* B = cast<BinaryOperator>(Terminator);
if (B->isLogicalOp()) { // && or ||
CFGBlock* ConfluenceBlock = (Block) ? Block : createBlock();
ConfluenceBlock->appendStmt(B);
FinishBlock(ConfluenceBlock);
// create the block evaluating the LHS
CFGBlock* LHSBlock = createBlock(false);
LHSBlock->setTerminator(B);
// create the block evaluating the RHS
Succ = ConfluenceBlock;
Block = NULL;
CFGBlock* RHSBlock = Visit(B->getRHS());
// Now link the LHSBlock with RHSBlock.
if (B->getOpcode() == BinaryOperator::LOr) {
LHSBlock->addSuccessor(ConfluenceBlock);
LHSBlock->addSuccessor(RHSBlock);
}
else {
assert (B->getOpcode() == BinaryOperator::LAnd);
LHSBlock->addSuccessor(RHSBlock);
LHSBlock->addSuccessor(ConfluenceBlock);
}
// Generate the blocks for evaluating the LHS.
Block = LHSBlock;
return addStmt(B->getLHS());
}
else if (B->getOpcode() == BinaryOperator::Comma) { // ,
Block->appendStmt(B);
addStmt(B->getRHS());
return addStmt(B->getLHS());
}
break;
}
case Stmt::ParenExprClass:
return WalkAST(cast<ParenExpr>(Terminator)->getSubExpr(), AlwaysAddStmt);
default:
break;
};
if (AlwaysAddStmt) Block->appendStmt(Terminator);
return WalkAST_VisitChildren(Terminator);
}
/// WalkAST_VisitDeclSubExpr - Utility method to add block-level expressions
/// for initializers in Decls.
CFGBlock* CFGBuilder::WalkAST_VisitDeclSubExpr(ScopedDecl* D) {
VarDecl* VD = dyn_cast<VarDecl>(D);
if (!VD)
return Block;
Expr* Init = VD->getInit();
if (!Init)
return Block;
// Optimization: Don't create separate block-level statements for literals.
switch (Init->getStmtClass()) {
case Stmt::IntegerLiteralClass:
case Stmt::CharacterLiteralClass:
case Stmt::StringLiteralClass:
break;
default:
Block = addStmt(Init);
}
return Block;
}
/// WalkAST_VisitChildren - Utility method to call WalkAST on the
/// children of a Stmt.
CFGBlock* CFGBuilder::WalkAST_VisitChildren(Stmt* Terminator) {
CFGBlock* B = Block;
for (Stmt::child_iterator I = Terminator->child_begin(), E = Terminator->child_end() ;
I != E; ++I)
if (*I) B = WalkAST(*I);
return B;
}
/// WalkAST_VisitStmtExpr - Utility method to handle (nested) statement
/// expressions (a GCC extension).
CFGBlock* CFGBuilder::WalkAST_VisitStmtExpr(StmtExpr* Terminator) {
Block->appendStmt(Terminator);
return VisitCompoundStmt(Terminator->getSubStmt());
}
/// VisitStmt - Handle statements with no branching control flow.
CFGBlock* CFGBuilder::VisitStmt(Stmt* Statement) {
// We cannot assume that we are in the middle of a basic block, since
// the CFG might only be constructed for this single statement. If
// we have no current basic block, just create one lazily.
if (!Block) Block = createBlock();
// Simply add the statement to the current block. We actually
// insert statements in reverse order; this order is reversed later
// when processing the containing element in the AST.
addStmt(Statement);
return Block;
}
CFGBlock* CFGBuilder::VisitNullStmt(NullStmt* Statement) {
return Block;
}
CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) {
CFGBlock* LastBlock = NULL;
for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend();
I != E; ++I ) {
LastBlock = Visit(*I);
}
return 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 and reverse its statements. That block
// is then the implicit successor for the "then" and "else" clauses.
// The block we were proccessing is now finished. Make it the
// successor block.
if (Block) {
Succ = Block;
FinishBlock(Block);
}
// Process the false branch. NULL out Block so that the recursive
// call to Visit will create a new basic block.
// Null out Block so that all successor
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;
ElseBlock = Visit(Else);
if (!ElseBlock) // Can occur when the Else body has all NullStmts.
ElseBlock = sv.get();
else if (Block)
FinishBlock(ElseBlock);
}
// Process the true branch. NULL out Block so that the recursive
// call to Visit will create a new basic block.
// Null out Block so that all successor
CFGBlock* ThenBlock;
{
Stmt* Then = I->getThen();
assert (Then);
SaveAndRestore<CFGBlock*> sv(Succ);
Block = NULL;
ThenBlock = Visit(Then);
if (!ThenBlock) // Can occur when the Then body has all NullStmts.
ThenBlock = sv.get();
else if (Block)
FinishBlock(ThenBlock);
}
// 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);
// Now add the successors.
Block->addSuccessor(ThenBlock);
Block->addSuccessor(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".
return addStmt(I->getCond()->IgnoreParens());
}
CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) {
// If we were in the middle of a block we stop processing that block
// and reverse its statements.
//
// 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.
if (Block) FinishBlock(Block);
// Create the new block.
Block = createBlock(false);
// The Exit block is the only successor.
Block->addSuccessor(&cfg->getExit());
// Add the return statement to the block. This may create new blocks
// if R contains control-flow (short-circuit operations).
return addStmt(R);
}
CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) {
// Get the block of the labeled statement. Add it to our map.
Visit(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) == LabelMap.end() && "label already in map");
LabelMap[ L ] = LabelBlock;
// 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);
FinishBlock(LabelBlock);
// 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::VisitGotoStmt(GotoStmt* G) {
// Goto is a control-flow statement. Thus we stop processing the
// current block and create a new one.
if (Block) FinishBlock(Block);
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(Block);
else
Block->addSuccessor(I->second);
return Block;
}
CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) {
// "for" is a control-flow statement. Thus we stop processing the
// current block.
CFGBlock* LoopSuccessor = NULL;
if (Block) {
FinishBlock(Block);
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(F);
// 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 = F->getCond()) {
Block = ExitConditionBlock;
EntryConditionBlock = addStmt(C);
if (Block) FinishBlock(EntryConditionBlock);
}
// The condition block is the implicit successor for the loop body as
// well as any code above the loop.
Succ = EntryConditionBlock;
// Now create the loop body.
{
assert (F->getBody());
// Save the current values for Block, Succ, and continue and break targets
SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ),
save_continue(ContinueTargetBlock),
save_break(BreakTargetBlock);
// All continues within this loop should go to the condition block
ContinueTargetBlock = EntryConditionBlock;
// All breaks should go to the code following the loop.
BreakTargetBlock = LoopSuccessor;
// Create a new block to contain the (bottom) of the loop body.
Block = NULL;
// If we have increment code, insert it at the end of the body block.
if (Stmt* I = F->getInc()) Block = addStmt(I);
// Now populate the body block, and in the process create new blocks
// as we walk the body of the loop.
CFGBlock* BodyBlock = Visit(F->getBody());
if (!BodyBlock)
BodyBlock = EntryConditionBlock; // can happen for "for (...;...; ) ;"
else if (Block)
FinishBlock(BodyBlock);
// This new body block is a successor to our "exit" condition block.
ExitConditionBlock->addSuccessor(BodyBlock);
}
// Link up the condition block with the code that follows the loop.
// (the false branch).
ExitConditionBlock->addSuccessor(LoopSuccessor);
// 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);
}
else {
// 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::VisitWhileStmt(WhileStmt* W) {
// "while" is a control-flow statement. Thus we stop processing the
// current block.
CFGBlock* LoopSuccessor = NULL;
if (Block) {
FinishBlock(Block);
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(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.
if (Stmt* C = W->getCond()) {
Block = ExitConditionBlock;
EntryConditionBlock = addStmt(C);
assert (Block == EntryConditionBlock);
if (Block) FinishBlock(EntryConditionBlock);
}
// The condition block is the implicit successor for the loop body as
// well as any code above the loop.
Succ = EntryConditionBlock;
// Process the loop body.
{
assert (W->getBody());
// Save the current values for Block, Succ, and continue and break targets
SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ),
save_continue(ContinueTargetBlock),
save_break(BreakTargetBlock);
// All continues within this loop should go to the condition block
ContinueTargetBlock = EntryConditionBlock;
// All breaks should go to the code following the loop.
BreakTargetBlock = LoopSuccessor;
// NULL out Block to force lazy instantiation of blocks for the body.
Block = NULL;
// Create the body. The returned block is the entry to the loop body.
CFGBlock* BodyBlock = Visit(W->getBody());
if (!BodyBlock)
BodyBlock = EntryConditionBlock; // can happen for "while(...) ;"
else if (Block)
FinishBlock(BodyBlock);
// Add the loop body entry as a successor to the condition.
ExitConditionBlock->addSuccessor(BodyBlock);
}
// Link up the condition block with the code that follows the loop.
// (the false branch).
ExitConditionBlock->addSuccessor(LoopSuccessor);
// 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::VisitDoStmt(DoStmt* D) {
// "do...while" is a control-flow statement. Thus we stop processing the
// current block.
CFGBlock* LoopSuccessor = NULL;
if (Block) {
FinishBlock(Block);
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) FinishBlock(EntryConditionBlock);
}
// The condition block is the implicit successor for the loop body.
Succ = EntryConditionBlock;
// 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),
save_continue(ContinueTargetBlock),
save_break(BreakTargetBlock);
// All continues within this loop should go to the condition block
ContinueTargetBlock = EntryConditionBlock;
// All breaks should go to the code following the loop.
BreakTargetBlock = LoopSuccessor;
// NULL out Block to force lazy instantiation of blocks for the body.
Block = NULL;
// Create the body. The returned block is the entry to the loop body.
BodyBlock = Visit(D->getBody());
if (!BodyBlock)
BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
else if (Block)
FinishBlock(BodyBlock);
// Add the loop body entry as a successor to the condition.
ExitConditionBlock->addSuccessor(BodyBlock);
}
// Link up the condition block with the code that follows the loop.
// (the false branch).
ExitConditionBlock->addSuccessor(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 (Block) FinishBlock(Block);
// 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. Handle this by not registering a successor.
if (ContinueTargetBlock) Block->addSuccessor(ContinueTargetBlock);
return Block;
}
CFGBlock* CFGBuilder::VisitBreakStmt(BreakStmt* B) {
// "break" is a control-flow statement. Thus we stop processing the
// current block.
if (Block) FinishBlock(Block);
// Now create a new block that ends with the continue statement.
Block = createBlock(false);
Block->setTerminator(B);
// If there is no target for the break, then we are looking at an
// incomplete AST. Handle this by not registering a successor.
if (BreakTargetBlock) Block->addSuccessor(BreakTargetBlock);
return Block;
}
CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) {
// "switch" is a control-flow statement. Thus we stop processing the
// current block.
CFGBlock* SwitchSuccessor = NULL;
if (Block) {
FinishBlock(Block);
SwitchSuccessor = Block;
}
else SwitchSuccessor = Succ;
// Save the current "switch" context.
SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
save_break(BreakTargetBlock),
save_default(DefaultCaseBlock);
// 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;
BreakTargetBlock = SwitchSuccessor;
// 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;
CFGBlock *BodyBlock = Visit(Terminator->getBody());
if (Block) FinishBlock(BodyBlock);
// If we have no "default:" case, the default transition is to the
// code following the switch body.
SwitchTerminatedBlock->addSuccessor(DefaultCaseBlock);
// Add the terminator and condition in the switch block.
SwitchTerminatedBlock->setTerminator(Terminator);
assert (Terminator->getCond() && "switch condition must be non-NULL");
Block = SwitchTerminatedBlock;
return addStmt(Terminator->getCond());
}
CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* Terminator) {
// CaseStmts are essentially labels, so they are the
// first statement in a block.
if (Terminator->getSubStmt()) Visit(Terminator->getSubStmt());
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(Terminator);
FinishBlock(CaseBlock);
// Add this block to the list of successors for the block with the
// switch statement.
assert (SwitchTerminatedBlock);
SwitchTerminatedBlock->addSuccessor(CaseBlock);
// 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 = CaseBlock;
return CaseBlock;
}
CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) {
if (Terminator->getSubStmt()) Visit(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);
FinishBlock(DefaultCaseBlock);
// 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::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 (Block) FinishBlock(Block);
Block = createBlock(false);
Block->setTerminator(I);
Block->addSuccessor(IBlock);
return addStmt(I->getTarget());
}
} // 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.
Blocks.push_front(CFGBlock(NumBlockIDs++));
// If this is the first block, set it as the Entry and Exit.
if (first_block) Entry = Exit = &front();
// Return the block.
return &front();
}
/// buildCFG - Constructs a CFG from an AST. Ownership of the returned
/// CFG is returned to the caller.
CFG* CFG::buildCFG(Stmt* Statement) {
CFGBuilder Builder;
return Builder.buildCFG(Statement);
}
/// reverseStmts - Reverses the orders of statements within a CFGBlock.
void CFGBlock::reverseStmts() { std::reverse(Stmts.begin(),Stmts.end()); }
//===----------------------------------------------------------------------===//
// CFG: Queries for BlkExprs.
//===----------------------------------------------------------------------===//
namespace {
typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy;
}
static void FindSubExprAssignments(Stmt* Terminator, llvm::SmallPtrSet<Expr*,50>& Set) {
if (!Terminator)
return;
for (Stmt::child_iterator I=Terminator->child_begin(), E=Terminator->child_end(); I!=E; ++I) {
if (!*I) continue;
if (BinaryOperator* B = dyn_cast<BinaryOperator>(*I))
if (B->isAssignmentOp()) Set.insert(B);
FindSubExprAssignments(*I, 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<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)
FindSubExprAssignments(*BI, 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)
if (Expr* Exp = dyn_cast<Expr>(*BI)) {
if (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* Terminator = 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 = Terminator->getSubStmt();
if (!C->body_empty()) {
unsigned x = M->size();
(*M)[C->body_back()] = x;
}
}
unsigned x = M->size();
(*M)[Exp] = x;
}
// Look at terminators. The condition is a block-level expression.
Expr* Exp = I->getTerminatorCondition();
if (Exp && M->find(Exp) == M->end()) {
unsigned x = M->size();
(*M)[Exp] = 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);
if (I == M->end()) return CFG::BlkExprNumTy();
else return CFG::BlkExprNumTy(I->second);
}
unsigned CFG::getNumBlkExprs() {
if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap))
return M->size();
else {
// 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();
}
}
//===----------------------------------------------------------------------===//
// Internal Block-Edge Set; used for modeling persistent <CFGBlock*,CFGBlock*>
// pairs for use with ProgramPoint.
//===----------------------------------------------------------------------===//
typedef std::pair<CFGBlock*,CFGBlock*> BPairTy;
namespace llvm {
template<> struct FoldingSetTrait<BPairTy*> {
static void Profile(const BPairTy* X, FoldingSetNodeID& profile) {
profile.AddPointer(X->first);
profile.AddPointer(X->second);
}
};
}
typedef llvm::FoldingSetNodeWrapper<BPairTy*> PersistPairTy;
typedef llvm::FoldingSet<PersistPairTy> BlkEdgeSetTy;
const std::pair<CFGBlock*,CFGBlock*>*
CFG::getBlockEdgeImpl(const CFGBlock* B1, const CFGBlock* B2) {
if (!BlkEdgeSet)
BlkEdgeSet = new BlkEdgeSetTy();
BlkEdgeSetTy* p = static_cast<BlkEdgeSetTy*>(BlkEdgeSet);
// Profile the edges.
llvm::FoldingSetNodeID profile;
void* InsertPos;
profile.AddPointer(B1);
profile.AddPointer(B2);
PersistPairTy* V = p->FindNodeOrInsertPos(profile, InsertPos);
if (!V) {
assert (llvm::AlignOf<BPairTy>::Alignment_LessEqual_8Bytes);
// Allocate the pair, forcing an 8-byte alignment.
BPairTy* pair = (BPairTy*) Alloc.Allocate(sizeof(*pair), 8);
new (pair) BPairTy(const_cast<CFGBlock*>(B1),
const_cast<CFGBlock*>(B2));
// Allocate the meta data to store the pair in the FoldingSet.
PersistPairTy* ppair = (PersistPairTy*) Alloc.Allocate<PersistPairTy>();
new (ppair) PersistPairTy(pair);
p->InsertNode(ppair, InsertPos);
return pair;
}
return V->getValue();
}
//===----------------------------------------------------------------------===//
// Cleanup: CFG dstor.
//===----------------------------------------------------------------------===//
CFG::~CFG() {
delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap);
delete reinterpret_cast<BlkEdgeSetTy*>(BlkEdgeSet);
}
//===----------------------------------------------------------------------===//
// CFG pretty printing
//===----------------------------------------------------------------------===//
namespace {
class VISIBILITY_HIDDEN StmtPrinterHelper : public PrinterHelper {
typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy;
StmtMapTy StmtMap;
signed CurrentBlock;
unsigned CurrentStmt;
public:
StmtPrinterHelper(const CFG* cfg) : CurrentBlock(0), CurrentStmt(0) {
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 )
StmtMap[*BI] = std::make_pair(I->getBlockID(),j);
}
}
virtual ~StmtPrinterHelper() {}
void setBlockID(signed i) { CurrentBlock = i; }
void setStmtID(unsigned i) { CurrentStmt = i; }
virtual bool handledStmt(Stmt* Terminator, std::ostream& OS) {
StmtMapTy::iterator I = StmtMap.find(Terminator);
if (I == StmtMap.end())
return false;
if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock
&& I->second.second == CurrentStmt)
return false;
OS << "[B" << I->second.first << "." << I->second.second << "]";
return true;
}
};
class VISIBILITY_HIDDEN CFGBlockTerminatorPrint
: public StmtVisitor<CFGBlockTerminatorPrint,void> {
std::ostream& OS;
StmtPrinterHelper* Helper;
public:
CFGBlockTerminatorPrint(std::ostream& os, StmtPrinterHelper* helper)
: OS(os), Helper(helper) {}
void VisitIfStmt(IfStmt* I) {
OS << "if ";
I->getCond()->printPretty(OS,Helper);
}
// Default case.
void VisitStmt(Stmt* Terminator) { Terminator->printPretty(OS); }
void VisitForStmt(ForStmt* F) {
OS << "for (" ;
if (F->getInit()) OS << "...";
OS << "; ";
if (Stmt* C = F->getCond()) C->printPretty(OS,Helper);
OS << "; ";
if (F->getInc()) OS << "...";
OS << ")";
}
void VisitWhileStmt(WhileStmt* W) {
OS << "while " ;
if (Stmt* C = W->getCond()) C->printPretty(OS,Helper);
}
void VisitDoStmt(DoStmt* D) {
OS << "do ... while ";
if (Stmt* C = D->getCond()) C->printPretty(OS,Helper);
}
void VisitSwitchStmt(SwitchStmt* Terminator) {
OS << "switch ";
Terminator->getCond()->printPretty(OS,Helper);
}
void VisitConditionalOperator(ConditionalOperator* C) {
C->getCond()->printPretty(OS,Helper);
OS << " ? ... : ...";
}
void VisitChooseExpr(ChooseExpr* C) {
OS << "__builtin_choose_expr( ";
C->getCond()->printPretty(OS,Helper);
OS << " )";
}
void VisitIndirectGotoStmt(IndirectGotoStmt* I) {
OS << "goto *";
I->getTarget()->printPretty(OS,Helper);
}
void VisitBinaryOperator(BinaryOperator* B) {
if (!B->isLogicalOp()) {
VisitExpr(B);
return;
}
B->getLHS()->printPretty(OS,Helper);
switch (B->getOpcode()) {
case BinaryOperator::LOr:
OS << " || ...";
return;
case BinaryOperator::LAnd:
OS << " && ...";
return;
default:
assert(false && "Invalid logical operator.");
}
}
void VisitExpr(Expr* E) {
E->printPretty(OS,Helper);
}
};
void print_stmt(std::ostream&OS, StmtPrinterHelper* Helper, Stmt* Terminator) {
if (Helper) {
// special printing for statement-expressions.
if (StmtExpr* SE = dyn_cast<StmtExpr>(Terminator)) {
CompoundStmt* Sub = SE->getSubStmt();
if (Sub->child_begin() != Sub->child_end()) {
OS << "({ ... ; ";
Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
OS << " })\n";
return;
}
}
// special printing for comma expressions.
if (BinaryOperator* B = dyn_cast<BinaryOperator>(Terminator)) {
if (B->getOpcode() == BinaryOperator::Comma) {
OS << "... , ";
Helper->handledStmt(B->getRHS(),OS);
OS << '\n';
return;
}
}
}
Terminator->printPretty(OS, Helper);
// Expressions need a newline.
if (isa<Expr>(Terminator)) OS << '\n';
}
void print_block(std::ostream& OS, const CFG* cfg, const CFGBlock& B,
StmtPrinterHelper* Helper, bool print_edges) {
if (Helper) Helper->setBlockID(B.getBlockID());
// Print the header.
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";
// Print the label of this block.
if (Stmt* Terminator = const_cast<Stmt*>(B.getLabel())) {
if (print_edges)
OS << " ";
if (LabelStmt* L = dyn_cast<LabelStmt>(Terminator))
OS << L->getName();
else if (CaseStmt* C = dyn_cast<CaseStmt>(Terminator)) {
OS << "case ";
C->getLHS()->printPretty(OS);
if (C->getRHS()) {
OS << " ... ";
C->getRHS()->printPretty(OS);
}
}
else if (isa<DefaultStmt>(Terminator))
OS << "default";
else
assert(false && "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 << std::setw(3) << j << ": ";
if (Helper)
Helper->setStmtID(j);
print_stmt(OS,Helper,*I);
}
// Print the terminator of this block.
if (B.getTerminator()) {
if (print_edges)
OS << " ";
OS << " T: ";
if (Helper) Helper->setBlockID(-1);
CFGBlockTerminatorPrint TPrinter(OS,Helper);
TPrinter.Visit(const_cast<Stmt*>(B.getTerminator()));
OS << '\n';
}
if (print_edges) {
// Print the predecessors of this block.
OS << " Predecessors (" << B.pred_size() << "):";
unsigned i = 0;
for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
I != E; ++I, ++i) {
if (i == 8 || (i-8) == 0)
OS << "\n ";
OS << " B" << (*I)->getBlockID();
}
OS << '\n';
// Print the successors of this block.
OS << " Successors (" << B.succ_size() << "):";
i = 0;
for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
I != E; ++I, ++i) {
if (i == 8 || (i-8) % 10 == 0)
OS << "\n ";
OS << " B" << (*I)->getBlockID();
}
OS << '\n';
}
}
} // end anonymous namespace
/// dump - A simple pretty printer of a CFG that outputs to stderr.
void CFG::dump() const { print(*llvm::cerr.stream()); }
/// print - A simple pretty printer of a CFG that outputs to an ostream.
void CFG::print(std::ostream& OS) const {
StmtPrinterHelper Helper(this);
// Print the entry block.
print_block(OS, this, getEntry(), &Helper, true);
// 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);
}
// Print the exit block.
print_block(OS, this, getExit(), &Helper, true);
}
/// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
void CFGBlock::dump(const CFG* cfg) const { print(*llvm::cerr.stream(), cfg); }
/// 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(std::ostream& OS, const CFG* cfg) const {
StmtPrinterHelper Helper(cfg);
print_block(OS, cfg, *this, &Helper, true);
}
/// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
void CFGBlock::printTerminator(std::ostream& OS) const {
CFGBlockTerminatorPrint TPrinter(OS,NULL);
TPrinter.Visit(const_cast<Stmt*>(getTerminator()));
}
Expr* CFGBlock::getTerminatorCondition() {
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::ConditionalOperatorClass:
E = cast<ConditionalOperator>(Terminator)->getCond();
break;
case Stmt::BinaryOperatorClass: // '&&' and '||'
E = cast<BinaryOperator>(Terminator)->getLHS();
break;
}
return E ? E->IgnoreParens() : NULL;
}
bool CFGBlock::hasBinaryBranchTerminator() const {
if (!Terminator)
return false;
Expr* E = NULL;
switch (Terminator->getStmtClass()) {
default:
return false;
case Stmt::ForStmtClass:
case Stmt::WhileStmtClass:
case Stmt::DoStmtClass:
case Stmt::IfStmtClass:
case Stmt::ChooseExprClass:
case Stmt::ConditionalOperatorClass:
case Stmt::BinaryOperatorClass:
return true;
}
return E ? E->IgnoreParens() : NULL;
}
//===----------------------------------------------------------------------===//
// CFG Graphviz Visualization
//===----------------------------------------------------------------------===//
#ifndef NDEBUG
static StmtPrinterHelper* GraphHelper;
#endif
void CFG::viewCFG() const {
#ifndef NDEBUG
StmtPrinterHelper H(this);
GraphHelper = &H;
llvm::ViewGraph(this,"CFG");
GraphHelper = NULL;
#endif
}
namespace llvm {
template<>
struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) {
#ifndef NDEBUG
std::ostringstream Out;
print_block(Out,Graph, *Node, GraphHelper, 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
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