gecko/build/clang-plugin/clang-plugin.cpp

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/* 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");