clang-1/lib/Analysis/CFGStmtMap.cpp

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//===--- CFGStmtMap.h - Map from Stmt* to CFGBlock* -----------*- 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 CFGStmtMap class, which defines a mapping from
// Stmt* to CFGBlock*
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/DenseMap.h"
#include "clang/AST/ParentMap.h"
#include "clang/Analysis/CFG.h"
#include "clang/Analysis/CFGStmtMap.h"
using namespace clang;
typedef llvm::DenseMap<const Stmt*, CFGBlock*> SMap;
static SMap *AsMap(void *m) { return (SMap*) m; }
CFGStmtMap::~CFGStmtMap() { delete AsMap(M); }
CFGBlock *CFGStmtMap::getBlock(Stmt *S) {
SMap *SM = AsMap(M);
Stmt *X = S;
// If 'S' isn't in the map, walk the ParentMap to see if one of its ancestors
// is in the map.
while (X) {
SMap::iterator I = SM->find(X);
if (I != SM->end()) {
CFGBlock *B = I->second;
// Memoize this lookup.
if (X != S)
(*SM)[X] = B;
return B;
}
X = PM->getParentIgnoreParens(X);
}
return 0;
}
static void Accumulate(SMap &SM, CFGBlock *B) {
// First walk the block-level expressions.
for (CFGBlock::iterator I = B->begin(), E = B->end(); I != E; ++I) {
const CFGElement &CE = *I;
Optional<CFGStmt> CS = CE.getAs<CFGStmt>();
if (!CS)
continue;
CFGBlock *&Entry = SM[CS->getStmt()];
// If 'Entry' is already initialized (e.g., a terminator was already),
// skip.
if (Entry)
continue;
Entry = B;
}
// Look at the label of the block.
if (Stmt *Label = B->getLabel())
SM[Label] = B;
// Finally, look at the terminator. If the terminator was already added
// because it is a block-level expression in another block, overwrite
// that mapping.
if (Stmt *Term = B->getTerminator())
SM[Term] = B;
}
CFGStmtMap *CFGStmtMap::Build(CFG *C, ParentMap *PM) {
if (!C || !PM)
return 0;
SMap *SM = new SMap();
// Walk all blocks, accumulating the block-level expressions, labels,
// and terminators.
for (CFG::iterator I = C->begin(), E = C->end(); I != E; ++I)
Accumulate(*SM, *I);
return new CFGStmtMap(PM, SM);
}