cling/lib/Interpreter/Value.cpp

349 lines
12 KiB
C++

//------------------------------------------------------------------------------
// CLING - the C++ LLVM-based InterpreterG :)
// author: Axel Naumann <axel@cern.ch>
//
// This file is dual-licensed: you can choose to license it under the University
// of Illinois Open Source License or the GNU Lesser General Public License. See
// LICENSE.TXT for details.
//------------------------------------------------------------------------------
#include "cling/Interpreter/Value.h"
#include "EnterUserCodeRAII.h"
#include "cling/Interpreter/Interpreter.h"
#include "cling/Interpreter/Transaction.h"
#include "cling/Utils/AST.h"
#include "cling/Utils/Casting.h"
#include "cling/Utils/Output.h"
#include "cling/Utils/UTF8.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CanonicalType.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/Type.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Overload.h"
#include "clang/Sema/Sema.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/raw_os_ostream.h"
#include <cstring>
namespace {
///\brief The allocation starts with this layout; it is followed by the
/// value's object at m_Payload. This class does not inherit from
/// llvm::RefCountedBase because deallocation cannot use this type but must
/// free the character array.
class AllocatedValue {
public:
typedef void (*DtorFunc_t)(void*);
private:
///\brief The reference count - once 0, this object will be deallocated.
mutable unsigned m_RefCnt;
///\brief The destructor function.
DtorFunc_t m_DtorFunc;
///\brief The size of the allocation (for arrays)
unsigned long m_AllocSize;
///\brief The number of elements in the array
unsigned long m_NElements;
///\brief The start of the allocation.
char m_Payload[1];
static const unsigned char kCanaryUnconstructedObject[8];
///\brief Return whether the contained object has been constructed,
/// or rather, whether the canary has been changed.
bool IsAlive() const
{
// If the canary values are still there
return (std::memcmp(getPayload(), kCanaryUnconstructedObject,
sizeof(kCanaryUnconstructedObject)) != 0);
}
///\brief Initialize the storage management part of the allocated object.
/// The allocator is referencing it, thus initialize m_RefCnt with 1.
///\param [in] dtorFunc - the function to be called before deallocation.
AllocatedValue(void* dtorFunc, size_t allocSize, size_t nElements):
m_RefCnt(1),
m_DtorFunc(cling::utils::VoidToFunctionPtr<DtorFunc_t>(dtorFunc)),
m_AllocSize(allocSize), m_NElements(nElements)
{}
public:
///\brief Allocate the memory needed by the AllocatedValue managing
/// an object of payloadSize bytes, and return the address of the
/// payload object.
static char* CreatePayload(unsigned payloadSize, void* dtorFunc,
size_t nElements) {
if (payloadSize < sizeof(kCanaryUnconstructedObject))
payloadSize = sizeof(kCanaryUnconstructedObject);
char* alloc = new char[AllocatedValue::getPayloadOffset() + payloadSize];
AllocatedValue* allocVal
= new (alloc) AllocatedValue(dtorFunc, payloadSize, nElements);
std::memcpy(allocVal->getPayload(), kCanaryUnconstructedObject,
sizeof(kCanaryUnconstructedObject));
return allocVal->getPayload();
}
const char* getPayload() const { return m_Payload; }
char* getPayload() { return m_Payload; }
static unsigned getPayloadOffset() {
static const AllocatedValue Dummy(0,0,0);
return Dummy.m_Payload - (const char*)&Dummy;
}
static AllocatedValue* getFromPayload(void* payload) {
return
reinterpret_cast<AllocatedValue*>((char*)payload - getPayloadOffset());
}
void Retain() { ++m_RefCnt; }
///\brief This object must be allocated as a char array. Deallocate it as
/// such.
void Release() {
assert (m_RefCnt > 0 && "Reference count is already zero.");
if (--m_RefCnt == 0) {
if (m_DtorFunc && IsAlive()) {
assert(m_NElements && "No elements!");
char* Payload = getPayload();
const auto Skip = m_AllocSize / m_NElements;
while (m_NElements-- != 0)
(*m_DtorFunc)(Payload + m_NElements * Skip);
}
delete [] (char*)this;
}
}
};
const unsigned char AllocatedValue::kCanaryUnconstructedObject[8]
= {0x4c, 0x37, 0xad, 0x8f, 0x2d, 0x23, 0x95, 0x91};
}
namespace cling {
Value::Value(const Value& other):
m_Storage(other.m_Storage), m_NeedsManagedAlloc(other.m_NeedsManagedAlloc),
m_TypeKind(other.m_TypeKind),
m_Type(other.m_Type), m_Interpreter(other.m_Interpreter) {
if (other.needsManagedAllocation())
AllocatedValue::getFromPayload(m_Storage.m_Ptr)->Retain();
}
static Value::TypeKind getCorrespondingTypeKind(clang::QualType QT) {
using namespace clang;
if (QT->isVoidType())
return Value::kVoid;
if (const auto *ET = dyn_cast<EnumType>(QT.getTypePtr()))
QT = ET->getDecl()->getIntegerType();
if (!QT->isBuiltinType() || QT->castAs<BuiltinType>()->isNullPtrType())
return Value::kPtrOrObjTy;
switch(QT->getAs<BuiltinType>()->getKind()) {
default:
#ifndef NDEBUG
QT->dump();
#endif // NDEBUG
assert(false && "Type not supported");
return Value::kInvalid;
#define X(type, name) \
case BuiltinType::name: return Value::k##name;
CLING_VALUE_BUILTIN_TYPES
#undef X
}
}
Value::Value(clang::QualType clangTy, Interpreter& Interp):
m_TypeKind(getCorrespondingTypeKind(clangTy)),
m_Type(clangTy.getAsOpaquePtr()), // FIXME: What if clangTy is freed?
m_Interpreter(&Interp) {
if (m_TypeKind == Value::kPtrOrObjTy) {
clang::QualType Canon = clangTy.getCanonicalType();
if (Canon->isPointerType() || Canon->isObjectType() ||
Canon->isReferenceType())
if (Canon->isRecordType() || Canon->isConstantArrayType() ||
Canon->isMemberPointerType())
m_NeedsManagedAlloc = true;
}
if (needsManagedAllocation())
ManagedAllocate();
}
Value& Value::operator =(const Value& other) {
// Release old value.
if (needsManagedAllocation())
AllocatedValue::getFromPayload(m_Storage.m_Ptr)->Release();
// Retain new one.
m_Type = other.m_Type;
m_Storage = other.m_Storage;
m_NeedsManagedAlloc = other.m_NeedsManagedAlloc;
m_TypeKind = other.m_TypeKind;
m_Interpreter = other.m_Interpreter;
if (needsManagedAllocation())
AllocatedValue::getFromPayload(m_Storage.m_Ptr)->Retain();
return *this;
}
Value& Value::operator =(Value&& other) {
// Release old value.
if (needsManagedAllocation())
AllocatedValue::getFromPayload(m_Storage.m_Ptr)->Release();
// Move new one.
m_Type = other.m_Type;
m_Storage = other.m_Storage;
m_NeedsManagedAlloc = other.m_NeedsManagedAlloc;
m_TypeKind = other.m_TypeKind;
m_Interpreter = other.m_Interpreter;
// Invalidate other so it will not release.
other.m_NeedsManagedAlloc = false;
other.m_TypeKind = kInvalid;
return *this;
}
Value::~Value() {
if (needsManagedAllocation())
AllocatedValue::getFromPayload(m_Storage.m_Ptr)->Release();
}
clang::QualType Value::getType() const {
return clang::QualType::getFromOpaquePtr(m_Type);
}
clang::ASTContext& Value::getASTContext() const {
return m_Interpreter->getCI()->getASTContext();
}
static size_t GetNumberOfElements(clang::QualType QT) {
if (const clang::ConstantArrayType* ArrTy
= llvm::dyn_cast<clang::ConstantArrayType>(QT.getTypePtr())) {
llvm::APInt arrSize(sizeof(size_t)*8, 1);
do {
arrSize *= ArrTy->getSize();
ArrTy = llvm::dyn_cast<clang::ConstantArrayType>(ArrTy->getElementType()
.getTypePtr());
} while (ArrTy);
return static_cast<size_t>(arrSize.getZExtValue());
}
return 1;
}
void Value::ManagedAllocate() {
assert(needsManagedAllocation() && "Does not need managed allocation");
void* dtorFunc = 0;
clang::QualType DtorType = getType();
// For arrays we destruct the elements.
if (const clang::ConstantArrayType* ArrTy
= llvm::dyn_cast<clang::ConstantArrayType>(DtorType.getTypePtr())) {
DtorType = ArrTy->getElementType();
}
if (const clang::RecordType* RTy = DtorType->getAs<clang::RecordType>()) {
LockCompilationDuringUserCodeExecutionRAII LCDUCER(*m_Interpreter);
dtorFunc = m_Interpreter->compileDtorCallFor(RTy->getDecl());
}
const clang::ASTContext& ctx = getASTContext();
unsigned payloadSize = ctx.getTypeSizeInChars(getType()).getQuantity();
m_Storage.m_Ptr = AllocatedValue::CreatePayload(payloadSize, dtorFunc,
GetNumberOfElements(getType()));
}
void Value::AssertTypeMismatch(const char* Type) const {
#ifndef NDEBUG
assert(isBuiltinType() && "Must be a builtin!");
const clang::BuiltinType *BT = getType()->castAs<clang::BuiltinType>();
clang::PrintingPolicy Policy = getASTContext().getPrintingPolicy();
#endif // NDEBUG
assert(BT->getName(Policy).equals(Type));
}
static clang::QualType getCorrespondingBuiltin(clang::ASTContext &C,
clang::BuiltinType::Kind K) {
using namespace clang;
switch(K) {
default:
assert(false && "Type not supported");
return {};
#define BUILTIN_TYPE(Id, SingletonId) \
case BuiltinType::Id: return C.SingletonId;
#include "clang/AST/BuiltinTypes.def"
}
}
#define X(type, name) \
template <> Value Value::Create(Interpreter& Interp, type val) { \
clang::ASTContext &C = Interp.getCI()->getASTContext(); \
clang::BuiltinType::Kind K = clang::BuiltinType::name; \
Value res = Value(getCorrespondingBuiltin(C, K), Interp); \
res.set##name(val); \
return res; \
} \
CLING_VALUE_BUILTIN_TYPES
#undef X
void Value::AssertOnUnsupportedTypeCast() const {
assert("unsupported type in Value, cannot cast!" && 0);
}
namespace valuePrinterInternal {
std::string printTypeInternal(const Value& V);
std::string printValueInternal(const Value& V);
} // end namespace valuePrinterInternal
void Value::print(llvm::raw_ostream& Out, bool Escape) const {
// Save the default type string representation so output can occur as one
// operation (calling printValueInternal below may write to stderr).
const std::string Type = valuePrinterInternal::printTypeInternal(*this);
// Get the value string representation, by printValue() method overloading
const std::string Val
= cling::valuePrinterInternal::printValueInternal(*this);
if (Escape) {
const char* Data = Val.data();
const size_t N = Val.size();
switch (N ? Data[0] : 0) {
case 'u': case 'U': case 'L':
if (N < 3 || Data[1] != '\"')
break;
LLVM_FALLTHROUGH;
case '\"':
// Unicode string, encoded as Utf-8
if (N > 2 && Data[N-1] == '\"') {
// Drop the terminating " so Utf-8 errors can be detected ("\xeA")
Out << Type << ' ';
utils::utf8::EscapeSequence().encode(Data, N-1, Out) << "\"\n";
return;
}
LLVM_FALLTHROUGH;
default:
break;
}
}
Out << Type << ' ' << Val << '\n';
}
void Value::dump(bool Escape) const {
print(cling::outs(), Escape);
}
} // end namespace cling