513 lines
20 KiB
C++
513 lines
20 KiB
C++
//===--- CFG.h - Classes for representing and building CFGs------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the CFG and CFGBuilder classes for representing and
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// building Control-Flow Graphs (CFGs) from ASTs.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_CFG_H
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#define LLVM_CLANG_CFG_H
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#include "llvm/ADT/PointerIntPair.h"
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#include "llvm/ADT/GraphTraits.h"
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#include "llvm/Support/Allocator.h"
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#include "llvm/Support/Casting.h"
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#include "clang/Analysis/Support/BumpVector.h"
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#include "clang/Basic/SourceLocation.h"
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#include <cassert>
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namespace llvm {
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class raw_ostream;
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}
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namespace clang {
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class Decl;
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class Stmt;
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class Expr;
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class CFG;
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class PrinterHelper;
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class LangOptions;
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class ASTContext;
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namespace {
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// An element of the CFG for implicit descructor calls implied by the language
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// rules.
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class Dtor {
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// Statement that introduces the variable.
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Stmt *S;
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// A token which ends the scope, return, goto, throw, }.
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SourceLocation Loc;
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public:
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Dtor(Stmt *s, SourceLocation l) : S(s), Loc(l) {
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}
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SourceLocation getLoc() { return Loc; }
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Stmt *getStmt() { return S; }
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};
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}
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/// CFGElement - Represents a top-level expression in a basic block.
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class CFGElement {
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llvm::PointerIntPair<Stmt *, 2> Data;
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public:
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enum Type { StartScope, EndScope };
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explicit CFGElement() {}
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CFGElement(Stmt *S, bool lvalue) : Data(S, lvalue ? 1 : 0) {}
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CFGElement(Stmt *S, Type t) : Data(S, t == StartScope ? 2 : 3) {}
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// CFGElement(Dtor *S, Type t) : Data(reinterpret_cast<Stmt*>(S), 4) {}
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Stmt *getStmt() const { return Data.getPointer(); }
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bool asLValue() const { return Data.getInt() == 1; }
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bool asStartScope() const { return Data.getInt() == 2; }
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bool asEndScope() const { return Data.getInt() == 3; }
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bool asDtor() const { return Data.getInt() == 4; }
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operator Stmt*() const { return getStmt(); }
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operator bool() const { return getStmt() != 0; }
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operator Dtor*() const { return reinterpret_cast<Dtor*>(getStmt()); }
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};
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/// CFGBlock - Represents a single basic block in a source-level CFG.
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/// It consists of:
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///
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/// (1) A set of statements/expressions (which may contain subexpressions).
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/// (2) A "terminator" statement (not in the set of statements).
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/// (3) A list of successors and predecessors.
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///
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/// Terminator: The terminator represents the type of control-flow that occurs
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/// at the end of the basic block. The terminator is a Stmt* referring to an
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/// AST node that has control-flow: if-statements, breaks, loops, etc.
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/// If the control-flow is conditional, the condition expression will appear
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/// within the set of statements in the block (usually the last statement).
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///
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/// Predecessors: the order in the set of predecessors is arbitrary.
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///
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/// Successors: the order in the set of successors is NOT arbitrary. We
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/// currently have the following orderings based on the terminator:
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///
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/// Terminator Successor Ordering
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/// -----------------------------------------------------
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/// if Then Block; Else Block
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/// ? operator LHS expression; RHS expression
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/// &&, || expression that uses result of && or ||, RHS
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///
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class CFGBlock {
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class StatementList {
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typedef BumpVector<CFGElement> ImplTy;
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ImplTy Impl;
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public:
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StatementList(BumpVectorContext &C) : Impl(C, 4) {}
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typedef std::reverse_iterator<ImplTy::iterator> iterator;
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typedef std::reverse_iterator<ImplTy::const_iterator> const_iterator;
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typedef ImplTy::iterator reverse_iterator;
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typedef ImplTy::const_iterator const_reverse_iterator;
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void push_back(CFGElement e, BumpVectorContext &C) { Impl.push_back(e, C); }
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CFGElement front() const { return Impl.back(); }
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CFGElement back() const { return Impl.front(); }
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iterator begin() { return Impl.rbegin(); }
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iterator end() { return Impl.rend(); }
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const_iterator begin() const { return Impl.rbegin(); }
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const_iterator end() const { return Impl.rend(); }
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reverse_iterator rbegin() { return Impl.begin(); }
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reverse_iterator rend() { return Impl.end(); }
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const_reverse_iterator rbegin() const { return Impl.begin(); }
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const_reverse_iterator rend() const { return Impl.end(); }
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CFGElement operator[](size_t i) const {
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assert(i < Impl.size());
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return Impl[Impl.size() - 1 - i];
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}
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size_t size() const { return Impl.size(); }
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bool empty() const { return Impl.empty(); }
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};
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/// Stmts - The set of statements in the basic block.
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StatementList Stmts;
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/// Label - An (optional) label that prefixes the executable
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/// statements in the block. When this variable is non-NULL, it is
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/// either an instance of LabelStmt, SwitchCase or CXXCatchStmt.
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Stmt *Label;
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/// Terminator - The terminator for a basic block that
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/// indicates the type of control-flow that occurs between a block
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/// and its successors.
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Stmt *Terminator;
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/// LoopTarget - Some blocks are used to represent the "loop edge" to
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/// the start of a loop from within the loop body. This Stmt* will be
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/// refer to the loop statement for such blocks (and be null otherwise).
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const Stmt *LoopTarget;
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/// BlockID - A numerical ID assigned to a CFGBlock during construction
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/// of the CFG.
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unsigned BlockID;
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/// Predecessors/Successors - Keep track of the predecessor / successor
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/// CFG blocks.
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typedef BumpVector<CFGBlock*> AdjacentBlocks;
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AdjacentBlocks Preds;
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AdjacentBlocks Succs;
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public:
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explicit CFGBlock(unsigned blockid, BumpVectorContext &C)
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: Stmts(C), Label(NULL), Terminator(NULL), LoopTarget(NULL),
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BlockID(blockid), Preds(C, 1), Succs(C, 1) {}
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~CFGBlock() {}
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// Statement iterators
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typedef StatementList::iterator iterator;
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typedef StatementList::const_iterator const_iterator;
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typedef StatementList::reverse_iterator reverse_iterator;
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typedef StatementList::const_reverse_iterator const_reverse_iterator;
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CFGElement front() const { return Stmts.front(); }
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CFGElement back() const { return Stmts.back(); }
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iterator begin() { return Stmts.begin(); }
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iterator end() { return Stmts.end(); }
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const_iterator begin() const { return Stmts.begin(); }
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const_iterator end() const { return Stmts.end(); }
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reverse_iterator rbegin() { return Stmts.rbegin(); }
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reverse_iterator rend() { return Stmts.rend(); }
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const_reverse_iterator rbegin() const { return Stmts.rbegin(); }
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const_reverse_iterator rend() const { return Stmts.rend(); }
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unsigned size() const { return Stmts.size(); }
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bool empty() const { return Stmts.empty(); }
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CFGElement operator[](size_t i) const { return Stmts[i]; }
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// CFG iterators
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typedef AdjacentBlocks::iterator pred_iterator;
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typedef AdjacentBlocks::const_iterator const_pred_iterator;
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typedef AdjacentBlocks::reverse_iterator pred_reverse_iterator;
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typedef AdjacentBlocks::const_reverse_iterator const_pred_reverse_iterator;
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typedef AdjacentBlocks::iterator succ_iterator;
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typedef AdjacentBlocks::const_iterator const_succ_iterator;
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typedef AdjacentBlocks::reverse_iterator succ_reverse_iterator;
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typedef AdjacentBlocks::const_reverse_iterator const_succ_reverse_iterator;
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pred_iterator pred_begin() { return Preds.begin(); }
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pred_iterator pred_end() { return Preds.end(); }
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const_pred_iterator pred_begin() const { return Preds.begin(); }
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const_pred_iterator pred_end() const { return Preds.end(); }
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pred_reverse_iterator pred_rbegin() { return Preds.rbegin(); }
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pred_reverse_iterator pred_rend() { return Preds.rend(); }
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const_pred_reverse_iterator pred_rbegin() const { return Preds.rbegin(); }
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const_pred_reverse_iterator pred_rend() const { return Preds.rend(); }
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succ_iterator succ_begin() { return Succs.begin(); }
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succ_iterator succ_end() { return Succs.end(); }
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const_succ_iterator succ_begin() const { return Succs.begin(); }
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const_succ_iterator succ_end() const { return Succs.end(); }
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succ_reverse_iterator succ_rbegin() { return Succs.rbegin(); }
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succ_reverse_iterator succ_rend() { return Succs.rend(); }
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const_succ_reverse_iterator succ_rbegin() const { return Succs.rbegin(); }
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const_succ_reverse_iterator succ_rend() const { return Succs.rend(); }
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unsigned succ_size() const { return Succs.size(); }
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bool succ_empty() const { return Succs.empty(); }
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unsigned pred_size() const { return Preds.size(); }
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bool pred_empty() const { return Preds.empty(); }
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// Manipulation of block contents
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void setTerminator(Stmt* Statement) { Terminator = Statement; }
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void setLabel(Stmt* Statement) { Label = Statement; }
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void setLoopTarget(const Stmt *loopTarget) { LoopTarget = loopTarget; }
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Stmt* getTerminator() { return Terminator; }
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const Stmt* getTerminator() const { return Terminator; }
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Stmt* getTerminatorCondition();
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const Stmt* getTerminatorCondition() const {
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return const_cast<CFGBlock*>(this)->getTerminatorCondition();
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}
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const Stmt *getLoopTarget() const { return LoopTarget; }
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bool hasBinaryBranchTerminator() const;
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Stmt* getLabel() { return Label; }
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const Stmt* getLabel() const { return Label; }
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unsigned getBlockID() const { return BlockID; }
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void dump(const CFG *cfg, const LangOptions &LO) const;
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void print(llvm::raw_ostream &OS, const CFG* cfg, const LangOptions &LO) const;
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void printTerminator(llvm::raw_ostream &OS, const LangOptions &LO) const;
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void addSuccessor(CFGBlock* Block, BumpVectorContext &C) {
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if (Block)
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Block->Preds.push_back(this, C);
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Succs.push_back(Block, C);
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}
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void appendStmt(Stmt* Statement, BumpVectorContext &C, bool asLValue) {
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Stmts.push_back(CFGElement(Statement, asLValue), C);
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}
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void StartScope(Stmt* S, BumpVectorContext &C) {
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Stmts.push_back(CFGElement(S, CFGElement::StartScope), C);
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}
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void EndScope(Stmt* S, BumpVectorContext &C) {
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Stmts.push_back(CFGElement(S, CFGElement::EndScope), C);
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}
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};
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/// CFG - Represents a source-level, intra-procedural CFG that represents the
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/// control-flow of a Stmt. The Stmt can represent an entire function body,
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/// or a single expression. A CFG will always contain one empty block that
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/// represents the Exit point of the CFG. A CFG will also contain a designated
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/// Entry block. The CFG solely represents control-flow; it consists of
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/// CFGBlocks which are simply containers of Stmt*'s in the AST the CFG
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/// was constructed from.
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class CFG {
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public:
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//===--------------------------------------------------------------------===//
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// CFG Construction & Manipulation.
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//===--------------------------------------------------------------------===//
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/// buildCFG - Builds a CFG from an AST. The responsibility to free the
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/// constructed CFG belongs to the caller.
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static CFG* buildCFG(const Decl *D, Stmt* AST, ASTContext *C,
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bool AddEHEdges = false,
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bool AddScopes = false /* NOT FULLY IMPLEMENTED.
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NOT READY FOR GENERAL USE. */);
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/// createBlock - Create a new block in the CFG. The CFG owns the block;
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/// the caller should not directly free it.
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CFGBlock* createBlock();
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/// setEntry - Set the entry block of the CFG. This is typically used
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/// only during CFG construction. Most CFG clients expect that the
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/// entry block has no predecessors and contains no statements.
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void setEntry(CFGBlock *B) { Entry = B; }
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/// setIndirectGotoBlock - Set the block used for indirect goto jumps.
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/// This is typically used only during CFG construction.
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void setIndirectGotoBlock(CFGBlock* B) { IndirectGotoBlock = B; }
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//===--------------------------------------------------------------------===//
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// Block Iterators
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//===--------------------------------------------------------------------===//
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typedef BumpVector<CFGBlock*> CFGBlockListTy;
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typedef CFGBlockListTy::iterator iterator;
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typedef CFGBlockListTy::const_iterator const_iterator;
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typedef std::reverse_iterator<iterator> reverse_iterator;
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typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
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CFGBlock& front() { return *Blocks.front(); }
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CFGBlock& back() { return *Blocks.back(); }
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iterator begin() { return Blocks.begin(); }
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iterator end() { return Blocks.end(); }
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const_iterator begin() const { return Blocks.begin(); }
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const_iterator end() const { return Blocks.end(); }
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reverse_iterator rbegin() { return Blocks.rbegin(); }
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reverse_iterator rend() { return Blocks.rend(); }
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const_reverse_iterator rbegin() const { return Blocks.rbegin(); }
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const_reverse_iterator rend() const { return Blocks.rend(); }
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CFGBlock& getEntry() { return *Entry; }
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const CFGBlock& getEntry() const { return *Entry; }
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CFGBlock& getExit() { return *Exit; }
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const CFGBlock& getExit() const { return *Exit; }
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CFGBlock* getIndirectGotoBlock() { return IndirectGotoBlock; }
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const CFGBlock* getIndirectGotoBlock() const { return IndirectGotoBlock; }
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//===--------------------------------------------------------------------===//
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// Member templates useful for various batch operations over CFGs.
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//===--------------------------------------------------------------------===//
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template <typename CALLBACK>
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void VisitBlockStmts(CALLBACK& O) const {
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for (const_iterator I=begin(), E=end(); I != E; ++I)
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for (CFGBlock::const_iterator BI=(*I)->begin(), BE=(*I)->end();
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BI != BE; ++BI)
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O(*BI);
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}
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//===--------------------------------------------------------------------===//
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// CFG Introspection.
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//===--------------------------------------------------------------------===//
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struct BlkExprNumTy {
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const signed Idx;
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explicit BlkExprNumTy(signed idx) : Idx(idx) {}
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explicit BlkExprNumTy() : Idx(-1) {}
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operator bool() const { return Idx >= 0; }
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operator unsigned() const { assert(Idx >=0); return (unsigned) Idx; }
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};
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bool isBlkExpr(const Stmt* S) { return getBlkExprNum(S); }
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BlkExprNumTy getBlkExprNum(const Stmt* S);
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unsigned getNumBlkExprs();
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/// getNumBlockIDs - Returns the total number of BlockIDs allocated (which
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/// start at 0).
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unsigned getNumBlockIDs() const { return NumBlockIDs; }
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//===--------------------------------------------------------------------===//
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// CFG Debugging: Pretty-Printing and Visualization.
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//===--------------------------------------------------------------------===//
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void viewCFG(const LangOptions &LO) const;
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void print(llvm::raw_ostream& OS, const LangOptions &LO) const;
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void dump(const LangOptions &LO) const;
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//===--------------------------------------------------------------------===//
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// Internal: constructors and data.
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//===--------------------------------------------------------------------===//
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CFG() : Entry(NULL), Exit(NULL), IndirectGotoBlock(NULL), NumBlockIDs(0),
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BlkExprMap(NULL), Blocks(BlkBVC, 10) {}
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~CFG();
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llvm::BumpPtrAllocator& getAllocator() {
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return BlkBVC.getAllocator();
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}
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BumpVectorContext &getBumpVectorContext() {
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return BlkBVC;
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}
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private:
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CFGBlock* Entry;
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CFGBlock* Exit;
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CFGBlock* IndirectGotoBlock; // Special block to contain collective dispatch
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// for indirect gotos
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unsigned NumBlockIDs;
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// BlkExprMap - An opaque pointer to prevent inclusion of DenseMap.h.
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// It represents a map from Expr* to integers to record the set of
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// block-level expressions and their "statement number" in the CFG.
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void* BlkExprMap;
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BumpVectorContext BlkBVC;
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CFGBlockListTy Blocks;
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};
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} // end namespace clang
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//===----------------------------------------------------------------------===//
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// GraphTraits specializations for CFG basic block graphs (source-level CFGs)
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//===----------------------------------------------------------------------===//
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namespace llvm {
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/// Implement simplify_type for CFGElement, so that we can dyn_cast from
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/// CFGElement to a specific Stmt class.
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template <> struct simplify_type<const ::clang::CFGElement> {
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typedef ::clang::Stmt* SimpleType;
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static SimpleType getSimplifiedValue(const ::clang::CFGElement &Val) {
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return Val.getStmt();
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}
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};
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template <> struct simplify_type< ::clang::CFGElement>
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: public simplify_type<const ::clang::CFGElement> {};
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// Traits for: CFGBlock
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template <> struct GraphTraits< ::clang::CFGBlock* > {
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typedef ::clang::CFGBlock NodeType;
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typedef ::clang::CFGBlock::succ_iterator ChildIteratorType;
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static NodeType* getEntryNode(::clang::CFGBlock* BB)
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{ return BB; }
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static inline ChildIteratorType child_begin(NodeType* N)
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{ return N->succ_begin(); }
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static inline ChildIteratorType child_end(NodeType* N)
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{ return N->succ_end(); }
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};
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template <> struct GraphTraits< const ::clang::CFGBlock* > {
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typedef const ::clang::CFGBlock NodeType;
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typedef ::clang::CFGBlock::const_succ_iterator ChildIteratorType;
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static NodeType* getEntryNode(const clang::CFGBlock* BB)
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{ return BB; }
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static inline ChildIteratorType child_begin(NodeType* N)
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{ return N->succ_begin(); }
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static inline ChildIteratorType child_end(NodeType* N)
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{ return N->succ_end(); }
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};
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template <> struct GraphTraits<Inverse<const ::clang::CFGBlock*> > {
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typedef const ::clang::CFGBlock NodeType;
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typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType;
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static NodeType *getEntryNode(Inverse<const ::clang::CFGBlock*> G)
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{ return G.Graph; }
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static inline ChildIteratorType child_begin(NodeType* N)
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{ return N->pred_begin(); }
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static inline ChildIteratorType child_end(NodeType* N)
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{ return N->pred_end(); }
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};
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// Traits for: CFG
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template <> struct GraphTraits< ::clang::CFG* >
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: public GraphTraits< ::clang::CFGBlock* > {
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typedef ::clang::CFG::iterator nodes_iterator;
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static NodeType *getEntryNode(::clang::CFG* F) { return &F->getEntry(); }
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static nodes_iterator nodes_begin(::clang::CFG* F) { return F->begin(); }
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static nodes_iterator nodes_end(::clang::CFG* F) { return F->end(); }
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};
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template <> struct GraphTraits<const ::clang::CFG* >
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: public GraphTraits<const ::clang::CFGBlock* > {
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typedef ::clang::CFG::const_iterator nodes_iterator;
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static NodeType *getEntryNode( const ::clang::CFG* F) {
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return &F->getEntry();
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}
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static nodes_iterator nodes_begin( const ::clang::CFG* F) {
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return F->begin();
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}
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static nodes_iterator nodes_end( const ::clang::CFG* F) {
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return F->end();
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}
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};
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template <> struct GraphTraits<Inverse<const ::clang::CFG*> >
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: public GraphTraits<Inverse<const ::clang::CFGBlock*> > {
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typedef ::clang::CFG::const_iterator nodes_iterator;
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|
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static NodeType *getEntryNode(const ::clang::CFG* F) { return &F->getExit(); }
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static nodes_iterator nodes_begin(const ::clang::CFG* F) { return F->begin();}
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static nodes_iterator nodes_end(const ::clang::CFG* F) { return F->end(); }
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};
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} // end llvm namespace
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#endif
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