Move the source-level CFG from libAST to libAnalysis.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@76092 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/BugReporter.cpp b/lib/Analysis/BugReporter.cpp
index 3db96ca..a691bb6 100644
--- a/lib/Analysis/BugReporter.cpp
+++ b/lib/Analysis/BugReporter.cpp
@@ -15,7 +15,7 @@
#include "clang/Analysis/PathSensitive/BugReporter.h"
#include "clang/Analysis/PathSensitive/GRExprEngine.h"
#include "clang/AST/ASTContext.h"
-#include "clang/AST/CFG.h"
+#include "clang/Analysis/CFG.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ParentMap.h"
#include "clang/AST/StmtObjC.h"
diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
new file mode 100644
index 0000000..d423716
--- /dev/null
+++ b/lib/Analysis/CFG.cpp
@@ -0,0 +1,1924 @@
+//===--- 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/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 <llvm/Support/Format.h>
+
+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(Decl* D) {
+ if (VarDecl* VD = dyn_cast<VarDecl>(D))
+ if (Expr* Ex = VD->getInit())
+ return Ex->getSourceRange().getEnd();
+
+ return D->getLocation();
+}
+
+/// 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* VisitBreakStmt(BreakStmt* B);
+ CFGBlock* VisitCaseStmt(CaseStmt* Terminator);
+ CFGBlock* VisitCompoundStmt(CompoundStmt* C);
+ CFGBlock* VisitContinueStmt(ContinueStmt* C);
+ CFGBlock* VisitDefaultStmt(DefaultStmt* D);
+ CFGBlock* VisitDoStmt(DoStmt* D);
+ CFGBlock* VisitForStmt(ForStmt* F);
+ CFGBlock* VisitGotoStmt(GotoStmt* G);
+ CFGBlock* VisitIfStmt(IfStmt* I);
+ CFGBlock* VisitIndirectGotoStmt(IndirectGotoStmt* I);
+ CFGBlock* VisitLabelStmt(LabelStmt* L);
+ CFGBlock* VisitNullStmt(NullStmt* Statement);
+ CFGBlock* VisitObjCForCollectionStmt(ObjCForCollectionStmt* S);
+ CFGBlock* VisitReturnStmt(ReturnStmt* R);
+ CFGBlock* VisitStmt(Stmt* Statement);
+ CFGBlock* VisitSwitchStmt(SwitchStmt* Terminator);
+ CFGBlock* VisitWhileStmt(WhileStmt* W);
+
+ // FIXME: Add support for ObjC-specific control-flow structures.
+
+ // NYS == Not Yet Supported
+ CFGBlock* NYS() {
+ badCFG = true;
+ return Block;
+ }
+
+ CFGBlock* VisitObjCAtTryStmt(ObjCAtTryStmt* S);
+ CFGBlock* VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) {
+ // FIXME: For now we pretend that @catch and the code it contains
+ // does not exit.
+ return Block;
+ }
+
+ // FIXME: This is not completely supported. We basically @throw like
+ // a 'return'.
+ CFGBlock* VisitObjCAtThrowStmt(ObjCAtThrowStmt* S);
+
+ CFGBlock* VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S);
+
+ // Blocks.
+ CFGBlock* VisitBlockExpr(BlockExpr* E) { return NYS(); }
+ CFGBlock* VisitBlockDeclRefExpr(BlockDeclRefExpr* E) { 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(Decl* D);
+ CFGBlock* WalkAST_VisitStmtExpr(StmtExpr* Terminator);
+ bool FinishBlock(CFGBlock* B);
+
+ bool badCFG;
+};
+
+// FIXME: Add support for dependent-sized array types in C++?
+// Does it even make sense to build a CFG for an uninstantiated template?
+static VariableArrayType* FindVA(Type* t) {
+ while (ArrayType* vt = dyn_cast<ArrayType>(t)) {
+ if (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(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.
+bool CFGBuilder::FinishBlock(CFGBlock* B) {
+ if (badCFG)
+ return false;
+
+ assert (B);
+ B->reverseStmts();
+ return true;
+}
+
+/// 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);
+ if (!FinishBlock(ConfluenceBlock))
+ return 0;
+
+ // 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());
+ if (!FinishBlock(LHSBlock))
+ return 0;
+ Block = NULL;
+ }
+
+ // Create the block for the RHS expression.
+ Succ = ConfluenceBlock;
+ CFGBlock* RHSBlock = Visit(C->getRHS());
+ if (!FinishBlock(RHSBlock))
+ return 0;
+
+ // 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);
+ if (!FinishBlock(ConfluenceBlock))
+ return 0;
+
+ Succ = ConfluenceBlock;
+ Block = NULL;
+ CFGBlock* LHSBlock = Visit(C->getLHS());
+ if (!FinishBlock(LHSBlock))
+ return 0;
+
+ Succ = ConfluenceBlock;
+ Block = NULL;
+ CFGBlock* RHSBlock = Visit(C->getRHS());
+ if (!FinishBlock(RHSBlock))
+ return 0;
+
+ Block = createBlock(false);
+ Block->addSuccessor(LHSBlock);
+ Block->addSuccessor(RHSBlock);
+ Block->setTerminator(C);
+ return addStmt(C->getCond());
+ }
+
+ case Stmt::DeclStmtClass: {
+ DeclStmt *DS = cast<DeclStmt>(Terminator);
+ if (DS->isSingleDecl()) {
+ Block->appendStmt(Terminator);
+ return WalkAST_VisitDeclSubExpr(DS->getSingleDecl());
+ }
+
+ CFGBlock* B = 0;
+
+ // FIXME: Add a reverse iterator for DeclStmt to avoid this
+ // extra copy.
+ typedef llvm::SmallVector<Decl*,10> BufTy;
+ BufTy Buf(DS->decl_begin(), DS->decl_end());
+
+ for (BufTy::reverse_iterator I=Buf.rbegin(), E=Buf.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* DS = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
+
+ // Append the fake DeclStmt to block.
+ Block->appendStmt(DS);
+ B = WalkAST_VisitDeclSubExpr(D);
+ }
+ 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::SizeOfAlignOfExprClass: {
+ SizeOfAlignOfExpr* E = cast<SizeOfAlignOfExpr>(Terminator);
+
+ // VLA types have expressions that must be evaluated.
+ if (E->isArgumentType()) {
+ for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr());
+ VA != 0; VA = FindVA(VA->getElementType().getTypePtr()))
+ addStmt(VA->getSizeExpr());
+ }
+ // Expressions in sizeof/alignof are not evaluated and thus have no
+ // control flow.
+ else
+ Block->appendStmt(Terminator);
+
+ return Block;
+ }
+
+ case Stmt::BinaryOperatorClass: {
+ BinaryOperator* B = cast<BinaryOperator>(Terminator);
+
+ if (B->isLogicalOp()) { // && or ||
+ CFGBlock* ConfluenceBlock = (Block) ? Block : createBlock();
+ ConfluenceBlock->appendStmt(B);
+ if (!FinishBlock(ConfluenceBlock))
+ return 0;
+
+ // 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());
+ if (!FinishBlock(RHSBlock))
+ return 0;
+
+ // 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;
+ }
+
+ // Blocks: No support for blocks ... yet
+ case Stmt::BlockExprClass:
+ case Stmt::BlockDeclRefExprClass:
+ return NYS();
+
+ 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(Decl* D) {
+ VarDecl* VD = dyn_cast<VarDecl>(D);
+
+ if (!VD)
+ return Block;
+
+ Expr* Init = VD->getInit();
+
+ if (Init) {
+ // 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);
+ }
+ }
+
+ // If the type of VD is a VLA, then we must process its size expressions.
+ for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0;
+ VA = FindVA(VA->getElementType().getTypePtr()))
+ Block = addStmt(VA->getSizeExpr());
+
+ 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 = Block;
+
+ 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;
+ if (!FinishBlock(Block))
+ return 0;
+ }
+
+ // 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) {
+ if (!FinishBlock(ElseBlock))
+ return 0;
+ }
+ }
+
+ // 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) {
+ // 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);
+ ThenBlock->addSuccessor(sv.get());
+ }
+ else if (Block) {
+ if (!FinishBlock(ThenBlock))
+ return 0;
+ }
+ }
+
+ // 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);
+ if (!FinishBlock(LabelBlock))
+ 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::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) {
+ if (!FinishBlock(Block))
+ 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(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) {
+ if (!FinishBlock(EntryConditionBlock))
+ return 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 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);
+
+ // Create a new block to contain the (bottom) of the loop body.
+ Block = NULL;
+
+ if (Stmt* I = F->getInc()) {
+ // Generate increment code in its own basic block. This is the target
+ // of continue statements.
+ Succ = Visit(I);
+ }
+ else {
+ // No increment code. Create a special, empty, block that is used as
+ // the target block for "looping back" to the start of the loop.
+ assert(Succ == EntryConditionBlock);
+ Succ = createBlock();
+ }
+
+ // Finish up the increment (or empty) block if it hasn't been already.
+ if (Block) {
+ assert(Block == Succ);
+ if (!FinishBlock(Block))
+ return 0;
+ Block = 0;
+ }
+
+ ContinueTargetBlock = Succ;
+
+ // 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.
+ ContinueTargetBlock->setLoopTarget(F);
+
+ // All breaks should go to the code following the loop.
+ BreakTargetBlock = LoopSuccessor;
+
+ // 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) {
+ if (!FinishBlock(BodyBlock))
+ return 0;
+ }
+
+ // 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::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 (!FinishBlock(Block))
+ return 0;
+ LoopSuccessor = Block;
+ Block = 0;
+ }
+ else LoopSuccessor = Succ;
+
+ // Build the condition blocks.
+ CFGBlock* ExitConditionBlock = createBlock(false);
+ CFGBlock* EntryConditionBlock = ExitConditionBlock;
+
+ // 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.
+ ExitConditionBlock->appendStmt(S);
+ Block = ExitConditionBlock;
+
+ // Walk the 'element' expression to see if there are any side-effects. We
+ // generate new blocks as necesary. We DON'T add the statement by default
+ // to the CFG unless it contains control-flow.
+ EntryConditionBlock = WalkAST(S->getElement(), false);
+ if (Block) {
+ if (!FinishBlock(EntryConditionBlock))
+ 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),
+ save_continue(ContinueTargetBlock), save_break(BreakTargetBlock);
+
+ BreakTargetBlock = LoopSuccessor;
+ ContinueTargetBlock = EntryConditionBlock;
+
+ CFGBlock* BodyBlock = Visit(S->getBody());
+
+ if (!BodyBlock)
+ BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;"
+ else if (Block) {
+ if (!FinishBlock(BodyBlock))
+ return 0;
+ }
+
+ // 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);
+
+ // Now create a prologue block to contain the collection expression.
+ Block = createBlock();
+ return addStmt(S->getCollection());
+}
+
+CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) {
+ // FIXME: Add locking 'primitives' to CFG for @synchronized.
+
+ // Inline the body.
+ CFGBlock *SyncBlock = Visit(S->getSynchBody());
+
+ // The sync body starts its own basic block. This makes it a little easier
+ // for diagnostic clients.
+ if (SyncBlock) {
+ if (!FinishBlock(SyncBlock))
+ return 0;
+
+ Block = 0;
+ }
+
+ Succ = SyncBlock;
+
+ // Inline the sync expression.
+ return Visit(S->getSynchExpr());
+}
+
+CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) {
+ return NYS();
+}
+
+CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) {
+ // "while" is a control-flow statement. Thus we stop processing the
+ // current block.
+
+ CFGBlock* LoopSuccessor = NULL;
+
+ if (Block) {
+ if (!FinishBlock(Block))
+ 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(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) {
+ if (!FinishBlock(EntryConditionBlock))
+ return 0;
+ }
+ }
+
+ // 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);
+
+ // Create an empty block to represent the transition block for looping
+ // back to the head of the loop.
+ Block = 0;
+ assert(Succ == EntryConditionBlock);
+ Succ = createBlock();
+ Succ->setLoopTarget(W);
+ ContinueTargetBlock = Succ;
+
+ // 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) {
+ if (!FinishBlock(BodyBlock))
+ return 0;
+ }
+
+ // 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::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
+ // and reverse its statements.
+ if (Block) {
+ if (!FinishBlock(Block))
+ return 0;
+ }
+
+ // Create the new block.
+ Block = createBlock(false);
+
+ // The Exit block is the only successor.
+ Block->addSuccessor(&cfg->getExit());
+
+ // Add the statement to the block. This may create new blocks
+ // if S contains control-flow (short-circuit operations).
+ return addStmt(S);
+}
+
+CFGBlock* CFGBuilder::VisitDoStmt(DoStmt* D) {
+ // "do...while" is a control-flow statement. Thus we stop processing the
+ // current block.
+
+ CFGBlock* LoopSuccessor = NULL;
+
+ if (Block) {
+ if (!FinishBlock(Block))
+ 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 (!FinishBlock(EntryConditionBlock))
+ return 0;
+ }
+ }
+
+ // 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) {
+ if (!FinishBlock(BodyBlock))
+ return 0;
+ }
+
+ // 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.
+ ExitConditionBlock->addSuccessor(LoopBackBlock);
+ }
+
+ // 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) {
+ if (!FinishBlock(Block))
+ 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 (ContinueTargetBlock)
+ Block->addSuccessor(ContinueTargetBlock);
+ else
+ badCFG = true;
+
+ return Block;
+}
+
+CFGBlock* CFGBuilder::VisitBreakStmt(BreakStmt* B) {
+ // "break" is a control-flow statement. Thus we stop processing the
+ // current block.
+ if (Block) {
+ if (!FinishBlock(Block))
+ return 0;
+ }
+
+ // 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. This means that the CFG cannot be constructed.
+ if (BreakTargetBlock)
+ Block->addSuccessor(BreakTargetBlock);
+ else
+ badCFG = true;
+
+
+ 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) {
+ if (!FinishBlock(Block))
+ return 0;
+ 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) {
+ if (!FinishBlock(BodyBlock))
+ return 0;
+ }
+
+ // 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);
+ if (!FinishBlock(CaseBlock))
+ return 0;
+
+ // 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);
+ if (!FinishBlock(DefaultCaseBlock))
+ 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::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) {
+ if (!FinishBlock(Block))
+ return 0;
+ }
+ 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.
+
+ 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);
+
+ 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();
+ }
+}
+
+//===----------------------------------------------------------------------===//
+// Cleanup: CFG dstor.
+//===----------------------------------------------------------------------===//
+
+CFG::~CFG() {
+ delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap);
+}
+
+//===----------------------------------------------------------------------===//
+// 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;
+ const LangOptions &LangOpts;
+public:
+
+ StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
+ : CurrentBlock(0), CurrentStmt(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 )
+ StmtMap[*BI] = std::make_pair(I->getBlockID(),j);
+ }
+ }
+
+ virtual ~StmtPrinterHelper() {}
+
+ const LangOptions &getLangOpts() const { return LangOpts; }
+ void setBlockID(signed i) { CurrentBlock = i; }
+ void setStmtID(unsigned i) { CurrentStmt = i; }
+
+ virtual bool handledStmt(Stmt* Terminator, llvm::raw_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;
+ }
+};
+} // end anonymous namespace
+
+
+namespace {
+class VISIBILITY_HIDDEN CFGBlockTerminatorPrint
+ : public StmtVisitor<CFGBlockTerminatorPrint,void> {
+
+ llvm::raw_ostream& OS;
+ StmtPrinterHelper* Helper;
+ PrintingPolicy Policy;
+
+public:
+ CFGBlockTerminatorPrint(llvm::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 VisitConditionalOperator(ConditionalOperator* 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 BinaryOperator::LOr:
+ OS << " || ...";
+ return;
+ case BinaryOperator::LAnd:
+ OS << " && ...";
+ return;
+ default:
+ assert(false && "Invalid logical operator.");
+ }
+ }
+
+ void VisitExpr(Expr* E) {
+ E->printPretty(OS, Helper, Policy);
+ }
+};
+} // end anonymous namespace
+
+
+static void print_stmt(llvm::raw_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, PrintingPolicy(Helper->getLangOpts()));
+
+ // Expressions need a newline.
+ if (isa<Expr>(Terminator)) OS << '\n';
+}
+
+static void print_block(llvm::raw_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, Helper,
+ PrintingPolicy(Helper->getLangOpts()));
+ if (C->getRHS()) {
+ OS << " ... ";
+ C->getRHS()->printPretty(OS, Helper,
+ PrintingPolicy(Helper->getLangOpts()));
+ }
+ }
+ 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 << llvm::format("%3d", 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,
+ PrintingPolicy(Helper->getLangOpts()));
+ 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';
+ }
+}
+
+
+/// dump - A simple pretty printer of a CFG that outputs to stderr.
+void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); }
+
+/// print - A simple pretty printer of a CFG that outputs to an ostream.
+void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const {
+ StmtPrinterHelper Helper(this, LO);
+
+ // 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);
+ OS.flush();
+}
+
+/// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
+void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const {
+ print(llvm::errs(), cfg, LO);
+}
+
+/// 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(llvm::raw_ostream& OS, const CFG* cfg,
+ const LangOptions &LO) const {
+ StmtPrinterHelper Helper(cfg, LO);
+ print_block(OS, cfg, *this, &Helper, true);
+}
+
+/// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
+void CFGBlock::printTerminator(llvm::raw_ostream &OS,
+ const LangOptions &LO) const {
+ CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO));
+ TPrinter.Visit(const_cast<Stmt*>(getTerminator()));
+}
+
+Stmt* 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;
+
+ case Stmt::ObjCForCollectionStmtClass:
+ return Terminator;
+ }
+
+ 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 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 {
+ static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph,
+ bool ShortNames) {
+
+#ifndef NDEBUG
+ std::string OutSStr;
+ llvm::raw_string_ostream Out(OutSStr);
+ 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
diff --git a/lib/Analysis/CMakeLists.txt b/lib/Analysis/CMakeLists.txt
index 2ef777d..6c49e8f 100644
--- a/lib/Analysis/CMakeLists.txt
+++ b/lib/Analysis/CMakeLists.txt
@@ -6,6 +6,7 @@
BasicStore.cpp
BasicValueFactory.cpp
BugReporter.cpp
+ CFG.cpp
CFRefCount.cpp
CallGraph.cpp
CheckDeadStores.cpp
diff --git a/lib/Analysis/LiveVariables.cpp b/lib/Analysis/LiveVariables.cpp
index aead7f4..c9828ce 100644
--- a/lib/Analysis/LiveVariables.cpp
+++ b/lib/Analysis/LiveVariables.cpp
@@ -15,7 +15,7 @@
#include "clang/Basic/SourceManager.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Expr.h"
-#include "clang/AST/CFG.h"
+#include "clang/Analysis/CFG.h"
#include "clang/Analysis/Visitors/CFGRecStmtDeclVisitor.h"
#include "clang/Analysis/FlowSensitive/DataflowSolver.h"
#include "llvm/ADT/SmallPtrSet.h"