DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (d1ed7de67f5a)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Basic/Version.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/FrontendPluginRegistry.h"
#include "clang/Frontend/MultiplexConsumer.h"
#include "clang/Sema/Sema.h"
#include "llvm/ADT/DenseMap.h"

#define CLANG_VERSION_FULL (CLANG_VERSION_MAJOR * 100 + CLANG_VERSION_MINOR)

using namespace llvm;
using namespace clang;

namespace {

using namespace clang::ast_matchers;
class DiagnosticsMatcher {
public:
  DiagnosticsMatcher();

  ASTConsumer *makeASTConsumer() {
    return astMatcher.newASTConsumer();
  }

private:
  class StackClassChecker : public MatchFinder::MatchCallback {
  public:
    virtual void run(const MatchFinder::MatchResult &Result);
    void noteInferred(QualType T, DiagnosticsEngine &Diag);
  };

  class NonHeapClassChecker : public MatchFinder::MatchCallback {
  public:
    virtual void run(const MatchFinder::MatchResult &Result);
    void noteInferred(QualType T, DiagnosticsEngine &Diag);
  };

  StackClassChecker stackClassChecker;
  NonHeapClassChecker nonheapClassChecker;
  MatchFinder astMatcher;
};

class MozChecker : public ASTConsumer, public RecursiveASTVisitor<MozChecker> {
  DiagnosticsEngine &Diag;
  const CompilerInstance &CI;
  DiagnosticsMatcher matcher;
public:
  MozChecker(const CompilerInstance &CI) : Diag(CI.getDiagnostics()), CI(CI) {}

  ASTConsumer *getOtherConsumer() {
    return matcher.makeASTConsumer();
  }

  virtual void HandleTranslationUnit(ASTContext &ctx) {
    TraverseDecl(ctx.getTranslationUnitDecl());
  }

  static bool hasCustomAnnotation(const Decl *d, const char *spelling) {
    AnnotateAttr *attr = d->getAttr<AnnotateAttr>();
    if (!attr)
      return false;

    return attr->getAnnotation() == spelling;
  }

  bool VisitCXXRecordDecl(CXXRecordDecl *d) {
    // We need definitions, not declarations
    if (!d->isThisDeclarationADefinition()) return true;

    // Look through all of our immediate bases to find methods that need to be
    // overridden
    typedef std::vector<CXXMethodDecl *> OverridesVector;
    OverridesVector must_overrides;
    for (CXXRecordDecl::base_class_iterator base = d->bases_begin(),
         e = d->bases_end(); base != e; ++base) {
      // The base is either a class (CXXRecordDecl) or it's a templated class...
      CXXRecordDecl *parent = base->getType()
        .getDesugaredType(d->getASTContext())->getAsCXXRecordDecl();
      // The parent might not be resolved to a type yet. In this case, we can't
      // do any checking here. For complete correctness, we should visit
      // template instantiations, but this case is likely to be rare, so we will
      // ignore it until it becomes important.
      if (!parent) {
        continue;
      }
      parent = parent->getDefinition();
      for (CXXRecordDecl::method_iterator M = parent->method_begin();
          M != parent->method_end(); ++M) {
        if (hasCustomAnnotation(*M, "moz_must_override"))
          must_overrides.push_back(*M);
      }
    }

    for (OverridesVector::iterator it = must_overrides.begin();
        it != must_overrides.end(); ++it) {
      bool overridden = false;
      for (CXXRecordDecl::method_iterator M = d->method_begin();
          !overridden && M != d->method_end(); ++M) {
        // The way that Clang checks if a method M overrides its parent method
        // is if the method has the same name but would not overload.
        if (M->getName() == (*it)->getName() &&
            !CI.getSema().IsOverload(*M, (*it), false))
          overridden = true;
      }
      if (!overridden) {
        unsigned overrideID = Diag.getDiagnosticIDs()->getCustomDiagID(
            DiagnosticIDs::Error, "%0 must override %1");
        unsigned overrideNote = Diag.getDiagnosticIDs()->getCustomDiagID(
            DiagnosticIDs::Note, "function to override is here");
        Diag.Report(d->getLocation(), overrideID) << d->getDeclName() <<
          (*it)->getDeclName();
        Diag.Report((*it)->getLocation(), overrideNote);
      }
    }
    return true;
  }
};

/**
 * Where classes may be allocated. Regular classes can be allocated anywhere,
 * non-heap classes on the stack or as static variables, and stack classes only
 * on the stack. Note that stack classes subsumes non-heap classes.
 */
enum ClassAllocationNature {
  RegularClass = 0,
  NonHeapClass = 1,
  StackClass = 2
};

/// A cached data of whether classes are stack classes, non-heap classes, or
/// neither.
DenseMap<const CXXRecordDecl *,
  std::pair<const Decl *, ClassAllocationNature> > inferredAllocCauses;

ClassAllocationNature getClassAttrs(QualType T);

ClassAllocationNature getClassAttrs(CXXRecordDecl *D) {
  // Normalize so that D points to the definition if it exists. If it doesn't,
  // then we can't allocate it anyways.
  if (!D->hasDefinition())
    return RegularClass;
  D = D->getDefinition();
  // Base class: anyone with this annotation is obviously a stack class
  if (MozChecker::hasCustomAnnotation(D, "moz_stack_class"))
    return StackClass;

  // See if we cached the result.
  DenseMap<const CXXRecordDecl *,
    std::pair<const Decl *, ClassAllocationNature> >::iterator it =
    inferredAllocCauses.find(D);
  if (it != inferredAllocCauses.end()) {
    return it->second.second;
  }

  // Continue looking, we might be a stack class yet. Even if we're a nonheap
  // class, it might be possible that we've inferred to be a stack class.
  ClassAllocationNature type = RegularClass;
  if (MozChecker::hasCustomAnnotation(D, "moz_nonheap_class")) {
    type = NonHeapClass;
  }
  inferredAllocCauses.insert(std::make_pair(D,
    std::make_pair((const Decl *)0, type)));

  // Look through all base cases to figure out if the parent is a stack class or
  // a non-heap class. Since we might later infer to also be a stack class, keep
  // going.
  for (CXXRecordDecl::base_class_iterator base = D->bases_begin(),
       e = D->bases_end(); base != e; ++base) {
    ClassAllocationNature super = getClassAttrs(base->getType());
    if (super == StackClass) {
      inferredAllocCauses[D] = std::make_pair(
        base->getType()->getAsCXXRecordDecl(), StackClass);
      return StackClass;
    } else if (super == NonHeapClass) {
      inferredAllocCauses[D] = std::make_pair(
        base->getType()->getAsCXXRecordDecl(), NonHeapClass);
      type = NonHeapClass;
    }
  }

  // Maybe it has a member which is a stack class.
  for (RecordDecl::field_iterator field = D->field_begin(), e = D->field_end();
       field != e; ++field) {
    ClassAllocationNature fieldType = getClassAttrs(field->getType());
    if (fieldType == StackClass) {
      inferredAllocCauses[D] = std::make_pair(*field, StackClass);
      return StackClass;
    } else if (fieldType == NonHeapClass) {
      inferredAllocCauses[D] = std::make_pair(*field, NonHeapClass);
      type = NonHeapClass;
    }
  }

  return type;
}

ClassAllocationNature getClassAttrs(QualType T) {
  while (const ArrayType *arrTy = T->getAsArrayTypeUnsafe())
    T = arrTy->getElementType();
  CXXRecordDecl *clazz = T->getAsCXXRecordDecl();
  return clazz ? getClassAttrs(clazz) : RegularClass;
}

}

namespace clang {
namespace ast_matchers {

/// This matcher will match any class with the stack class assertion or an
/// array of such classes.
AST_MATCHER(QualType, stackClassAggregate) {
  return getClassAttrs(Node) == StackClass;
}

/// This matcher will match any class with the stack class assertion or an
/// array of such classes.
AST_MATCHER(QualType, nonheapClassAggregate) {
  return getClassAttrs(Node) == NonHeapClass;
}

/// This matcher will match any function declaration that is declared as a heap
/// allocator.
AST_MATCHER(FunctionDecl, heapAllocator) {
  return MozChecker::hasCustomAnnotation(&Node, "moz_heap_allocator");
}
}
}

namespace {

bool isPlacementNew(const CXXNewExpr *expr) {
  // Regular new expressions aren't placement new
  if (expr->getNumPlacementArgs() == 0)
    return false;
  if (MozChecker::hasCustomAnnotation(expr->getOperatorNew(),
      "moz_heap_allocator"))
    return false;
  return true;
}

DiagnosticsMatcher::DiagnosticsMatcher() {
  // Stack class assertion: non-local variables of a stack class are forbidden
  // (non-localness checked in the callback)
  astMatcher.addMatcher(varDecl(hasType(stackClassAggregate())).bind("node"),
    &stackClassChecker);
  // Stack class assertion: new stack class is forbidden (unless placement new)
  astMatcher.addMatcher(newExpr(hasType(pointerType(
      pointee(stackClassAggregate())
    ))).bind("node"), &stackClassChecker);
  // Non-heap class assertion: new non-heap class is forbidden (unless placement
  // new)
  astMatcher.addMatcher(newExpr(hasType(pointerType(
      pointee(nonheapClassAggregate())
    ))).bind("node"), &nonheapClassChecker);

  // Any heap allocation function that returns a non-heap or a stack class is
  // definitely doing something wrong
  astMatcher.addMatcher(callExpr(callee(functionDecl(allOf(heapAllocator(),
      returns(pointerType(pointee(nonheapClassAggregate()))))))).bind("node"),
    &nonheapClassChecker);
  astMatcher.addMatcher(callExpr(callee(functionDecl(allOf(heapAllocator(),
      returns(pointerType(pointee(stackClassAggregate()))))))).bind("node"),
    &stackClassChecker);
}

void DiagnosticsMatcher::StackClassChecker::run(
    const MatchFinder::MatchResult &Result) {
  DiagnosticsEngine &Diag = Result.Context->getDiagnostics();
  unsigned stackID = Diag.getDiagnosticIDs()->getCustomDiagID(
    DiagnosticIDs::Error, "variable of type %0 only valid on the stack");
  if (const VarDecl *d = Result.Nodes.getNodeAs<VarDecl>("node")) {
    // Ignore the match if it's a local variable.
    if (d->hasLocalStorage())
      return;

    Diag.Report(d->getLocation(), stackID) << d->getType();
    noteInferred(d->getType(), Diag);
  } else if (const CXXNewExpr *expr =
      Result.Nodes.getNodeAs<CXXNewExpr>("node")) {
    // If it's placement new, then this match doesn't count.
    if (isPlacementNew(expr))
      return;
    Diag.Report(expr->getStartLoc(), stackID) << expr->getAllocatedType();
    noteInferred(expr->getAllocatedType(), Diag);
  } else if (const CallExpr *expr =
      Result.Nodes.getNodeAs<CallExpr>("node")) {
    QualType badType = expr->getCallReturnType()->getPointeeType();
    Diag.Report(expr->getLocStart(), stackID) << badType;
    noteInferred(badType, Diag);
  }
}

void DiagnosticsMatcher::StackClassChecker::noteInferred(QualType T,
    DiagnosticsEngine &Diag) {
  unsigned inheritsID = Diag.getDiagnosticIDs()->getCustomDiagID(
    DiagnosticIDs::Note,
    "%0 is a stack class because it inherits from a stack class %1");
  unsigned memberID = Diag.getDiagnosticIDs()->getCustomDiagID(
    DiagnosticIDs::Note,
    "%0 is a stack class because member %1 is a stack class %2");

  // Find the CXXRecordDecl that is the stack class of interest
  while (const ArrayType *arrTy = T->getAsArrayTypeUnsafe())
    T = arrTy->getElementType();
  CXXRecordDecl *clazz = T->getAsCXXRecordDecl();

  // Direct result, we're done.
  if (MozChecker::hasCustomAnnotation(clazz, "moz_stack_class"))
    return;

  const Decl *cause = inferredAllocCauses[clazz].first;
  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(cause)) {
    Diag.Report(clazz->getLocation(), inheritsID) << T << CRD->getDeclName();
  } else if (const FieldDecl *FD = dyn_cast<FieldDecl>(cause)) {
    Diag.Report(FD->getLocation(), memberID) << T << FD << FD->getType();
  }
  
  // Recursively follow this back.
  noteInferred(cast<ValueDecl>(cause)->getType(), Diag);
}

void DiagnosticsMatcher::NonHeapClassChecker::run(
    const MatchFinder::MatchResult &Result) {
  DiagnosticsEngine &Diag = Result.Context->getDiagnostics();
  unsigned stackID = Diag.getDiagnosticIDs()->getCustomDiagID(
    DiagnosticIDs::Error, "variable of type %0 is not valid on the heap");
  if (const CXXNewExpr *expr = Result.Nodes.getNodeAs<CXXNewExpr>("node")) {
    // If it's placement new, then this match doesn't count.
    if (isPlacementNew(expr))
      return;
    Diag.Report(expr->getStartLoc(), stackID) << expr->getAllocatedType();
    noteInferred(expr->getAllocatedType(), Diag);
  } else if (const CallExpr *expr = Result.Nodes.getNodeAs<CallExpr>("node")) {
    QualType badType = expr->getCallReturnType()->getPointeeType();
    Diag.Report(expr->getLocStart(), stackID) << badType;
    noteInferred(badType, Diag);
  }
}

void DiagnosticsMatcher::NonHeapClassChecker::noteInferred(QualType T,
    DiagnosticsEngine &Diag) {
  unsigned inheritsID = Diag.getDiagnosticIDs()->getCustomDiagID(
    DiagnosticIDs::Note,
    "%0 is a non-heap class because it inherits from a non-heap class %1");
  unsigned memberID = Diag.getDiagnosticIDs()->getCustomDiagID(
    DiagnosticIDs::Note,
    "%0 is a non-heap class because member %1 is a non-heap class %2");

  // Find the CXXRecordDecl that is the stack class of interest
  while (const ArrayType *arrTy = T->getAsArrayTypeUnsafe())
    T = arrTy->getElementType();
  CXXRecordDecl *clazz = T->getAsCXXRecordDecl();

  // Direct result, we're done.
  if (MozChecker::hasCustomAnnotation(clazz, "moz_nonheap_class"))
    return;

  const Decl *cause = inferredAllocCauses[clazz].first;
  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(cause)) {
    Diag.Report(clazz->getLocation(), inheritsID) << T << CRD->getDeclName();
  } else if (const FieldDecl *FD = dyn_cast<FieldDecl>(cause)) {
    Diag.Report(FD->getLocation(), memberID) << T << FD << FD->getType();
  }
  
  // Recursively follow this back.
  noteInferred(cast<ValueDecl>(cause)->getType(), Diag);
}

class MozCheckAction : public PluginASTAction {
public:
  ASTConsumer *CreateASTConsumer(CompilerInstance &CI, StringRef fileName) {
    MozChecker *checker = new MozChecker(CI);

    ASTConsumer *consumers[] = { checker, checker->getOtherConsumer() };
    return new MultiplexConsumer(consumers);
  }

  bool ParseArgs(const CompilerInstance &CI,
                 const std::vector<std::string> &args) {
    return true;
  }
};
}

static FrontendPluginRegistry::Add<MozCheckAction>
X("moz-check", "check moz action");