/*******************************************************************************
* Copyright (c) 2011, 2015 Google, Inc and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Sergey Prigogin (Google) - initial API and implementation
* Nathan Ridge
*******************************************************************************/
package org.eclipse.cdt.internal.core.dom.parser;
import java.util.HashMap;
import java.util.Map;
import org.eclipse.cdt.core.dom.ast.IASTNode;
import org.eclipse.cdt.core.dom.ast.IASTPreprocessorMacroDefinition;
import org.eclipse.cdt.core.dom.ast.IASTTranslationUnit;
import org.eclipse.cdt.core.dom.ast.IArrayType;
import org.eclipse.cdt.core.dom.ast.IBasicType;
import org.eclipse.cdt.core.dom.ast.IBasicType.Kind;
import org.eclipse.cdt.core.dom.ast.IBinding;
import org.eclipse.cdt.core.dom.ast.ICompositeType;
import org.eclipse.cdt.core.dom.ast.IEnumeration;
import org.eclipse.cdt.core.dom.ast.IField;
import org.eclipse.cdt.core.dom.ast.IFunctionType;
import org.eclipse.cdt.core.dom.ast.IPointerType;
import org.eclipse.cdt.core.dom.ast.IType;
import org.eclipse.cdt.core.dom.ast.IValue;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPBase;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPClassType;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPMethod;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPPointerToMemberType;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPReferenceType;
import org.eclipse.cdt.internal.core.dom.parser.cpp.ClassTypeHelper;
import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.SemanticUtil;
import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.TypeTraits;
/**
* Calculator of in-memory size and alignment of types.
*/
public class SizeofCalculator {
/** Size and alignment pair */
public static class SizeAndAlignment {
public final long size;
public final int alignment;
public SizeAndAlignment(long size, int alignment) {
this.size = size;
this.alignment = alignment;
}
}
private static final SizeofCalculator defaultInstance = new SizeofCalculator();
private static final SizeAndAlignment SIZE_1 = new SizeAndAlignment(1, 1);
public final SizeAndAlignment size_2;
public final SizeAndAlignment size_4;
public final SizeAndAlignment size_8;
public final SizeAndAlignment size_16;
public final SizeAndAlignment sizeof_pointer;
public final SizeAndAlignment sizeof_int;
public final SizeAndAlignment sizeof_long;
public final SizeAndAlignment sizeof_long_long;
public final SizeAndAlignment sizeof_int128;
public final SizeAndAlignment sizeof_short;
public final SizeAndAlignment sizeof_bool;
public final SizeAndAlignment sizeof_wchar_t;
public final SizeAndAlignment sizeof_float;
public final SizeAndAlignment sizeof_complex_float;
public final SizeAndAlignment sizeof_double;
public final SizeAndAlignment sizeof_complex_double;
public final SizeAndAlignment sizeof_long_double;
public final SizeAndAlignment sizeof_complex_long_double;
public final SizeAndAlignment sizeof_float128;
public final SizeAndAlignment sizeof_complex_float128;
public final SizeAndAlignment sizeof_decimal32;
public final SizeAndAlignment sizeof_decimal64;
public final SizeAndAlignment sizeof_decimal128;
private final IASTTranslationUnit ast;
/**
* Calculates size and alignment for the given type.
*
* @param type the type to get size and alignment for.
* @param point a node belonging to the AST of the translation unit defining context for
* the size calculation.
* @return size and alignment, or {@code null} if could not be calculated.
*/
public static SizeAndAlignment getSizeAndAlignment(IType type, IASTNode point) {
SizeofCalculator calc = point == null ?
getDefault() : ((ASTTranslationUnit) point.getTranslationUnit()).getSizeofCalculator();
return calc.sizeAndAlignment(type);
}
/**
* Returns the default instance of sizeof calculator. The default instance is not aware
* of the parser configuration and can only calculate sizes that are the same across all
* C/C++ implementations.
*/
public static SizeofCalculator getDefault() {
return defaultInstance;
}
public SizeofCalculator(IASTTranslationUnit ast) {
this.ast = ast;
int maxAlignment = 32;
Map<String, String> sizeofMacros = new HashMap<String, String>();
for (IASTPreprocessorMacroDefinition macro : ast.getBuiltinMacroDefinitions()) {
String name = macro.getName().toString();
if ("__BIGGEST_ALIGNMENT__".equals(name)) { //$NON-NLS-1$
try {
maxAlignment = Integer.parseInt(macro.getExpansion());
} catch (NumberFormatException e) {
// Ignore.
}
} else {
if (name.startsWith("__SIZEOF_")) { //$NON-NLS-1$
sizeofMacros.put(name, macro.getExpansion());
}
}
}
size_2 = new SizeAndAlignment(2, Math.min(2, maxAlignment));
size_4 = new SizeAndAlignment(4, Math.min(4, maxAlignment));
size_8 = new SizeAndAlignment(8, Math.min(8, maxAlignment));
size_16 = new SizeAndAlignment(16, Math.min(16, maxAlignment));
sizeof_pointer = getSize(sizeofMacros, "__SIZEOF_POINTER__", maxAlignment); //$NON-NLS-1$
sizeof_int = getSize(sizeofMacros, "__SIZEOF_INT__", maxAlignment); //$NON-NLS-1$
sizeof_long = getSize(sizeofMacros, "__SIZEOF_LONG__", maxAlignment); //$NON-NLS-1$
sizeof_long_long = getSize(sizeofMacros, "__SIZEOF_LONG_LONG__", maxAlignment); //$NON-NLS-1$
sizeof_int128 = getSize(sizeofMacros, "__SIZEOF_INT128__", maxAlignment); //$NON-NLS-1$
sizeof_short = getSize(sizeofMacros, "__SIZEOF_SHORT__", maxAlignment); //$NON-NLS-1$
SizeAndAlignment size = getSize(sizeofMacros, "__SIZEOF_BOOL__", maxAlignment); //$NON-NLS-1$
// __SIZEOF_BOOL__ is not defined by GCC but sizeof(bool) is needed for template resolution.
if (size == null)
size = SIZE_1;
sizeof_bool = size;
sizeof_wchar_t = getSize(sizeofMacros, "__SIZEOF_WCHAR_T__", maxAlignment); //$NON-NLS-1$
sizeof_float = getSize(sizeofMacros, "__SIZEOF_FLOAT__", maxAlignment); //$NON-NLS-1$
sizeof_complex_float = getSizeOfPair(sizeof_float);
sizeof_double = getSize(sizeofMacros, "__SIZEOF_DOUBLE__", maxAlignment); //$NON-NLS-1$
sizeof_complex_double = getSizeOfPair(sizeof_double);
sizeof_long_double = getSize(sizeofMacros, "__SIZEOF_LONG_DOUBLE__", maxAlignment); //$NON-NLS-1$
sizeof_complex_long_double = getSizeOfPair(sizeof_long_double);
sizeof_float128 = size_16; // GCC does not define __SIZEOF_FLOAT128__
sizeof_complex_float128 = getSizeOfPair(sizeof_float128);
sizeof_decimal32 = size_4; // GCC does not define __SIZEOF_DECIMAL32__
sizeof_decimal64 = size_8; // GCC does not define __SIZEOF_DECIMAL64__
sizeof_decimal128 = size_16; // GCC does not define __SIZEOF_DECIMAL128__
}
private SizeofCalculator() {
size_2 = new SizeAndAlignment(2, 2);
size_4 = new SizeAndAlignment(4, 4);
size_8 = new SizeAndAlignment(8, 8);
size_16 = new SizeAndAlignment(16, 16);
sizeof_pointer = null;
sizeof_int = null;
sizeof_long = null;
sizeof_long_long = null;
sizeof_int128 = size_16;
sizeof_short = null;
sizeof_bool = SIZE_1;
sizeof_wchar_t = null;
sizeof_float = null;
sizeof_complex_float = null;
sizeof_double = null;
sizeof_complex_double = null;
sizeof_long_double = null;
sizeof_complex_long_double = null;
sizeof_float128 = size_16;
sizeof_complex_float128 = getSizeOfPair(sizeof_float128);
sizeof_decimal32 = size_4;
sizeof_decimal64 = size_8;
sizeof_decimal128 = size_16;
ast = null;
}
/**
* Calculates size and alignment for the given type.
* @param type the type to get size and alignment for.
* @return size and alignment, or {@code null} if could not be calculated.
*/
public SizeAndAlignment sizeAndAlignment(IType type) {
type = SemanticUtil.getNestedType(type, SemanticUtil.CVTYPE | SemanticUtil.TDEF);
if (type instanceof IFunctionType) {
return sizeAndAlignment(((IFunctionType) type).getReturnType());
}
if (type instanceof IBasicType) {
return sizeAndAlignment((IBasicType) type);
}
// [expr.sizeof]/2: "When applied to a reference or a reference type,
// the result is the size of the referenced type."
if (type instanceof ICPPReferenceType) {
return sizeAndAlignment(((ICPPReferenceType) type).getType());
}
if (type instanceof IPointerType) {
if (type instanceof ICPPPointerToMemberType)
return null;
return sizeof_pointer;
}
if (type instanceof IEnumeration) {
return sizeAndAlignment((IEnumeration) type);
}
if (type instanceof IArrayType) {
return sizeAndAlignment((IArrayType) type);
}
if (type instanceof ICompositeType) {
return sizeAndAlignment((ICompositeType) type);
}
return null;
}
/**
* Returns size and alignment of pointer types.
* @return size and alignment of pointer types, or {@code null} if unknown.
*/
public SizeAndAlignment sizeAndAlignmentOfPointer() {
return sizeof_pointer;
}
private SizeAndAlignment sizeAndAlignment(IBasicType type) {
Kind kind = type.getKind();
switch (kind) {
case eBoolean:
return sizeof_bool;
case eChar:
return SIZE_1;
case eInt:
return type.isShort() ? sizeof_short : type.isLong() ? sizeof_long :
type.isLongLong() ? sizeof_long_long : sizeof_int;
case eInt128:
return sizeof_int128;
case eFloat:
return type.isComplex() ? sizeof_complex_float : sizeof_float;
case eDouble:
return type.isComplex() ?
(type.isLong() ? sizeof_complex_long_double : sizeof_complex_double) :
(type.isLong() ? sizeof_long_double : sizeof_double);
case eFloat128:
return type.isComplex() ? sizeof_complex_float128 : sizeof_float128;
case eDecimal32:
return sizeof_decimal32;
case eDecimal64:
return sizeof_decimal64;
case eDecimal128:
return sizeof_decimal128;
case eWChar:
return sizeof_wchar_t;
case eChar16:
return size_2;
case eChar32:
return size_4;
case eNullPtr:
return sizeof_pointer;
default:
return null;
}
}
private SizeAndAlignment sizeAndAlignment(IEnumeration type) {
IType underlyingType = TypeTraits.underlyingType(type);
if (underlyingType instanceof IBasicType) {
return sizeAndAlignment((IBasicType) underlyingType);
}
return null;
}
private SizeAndAlignment sizeAndAlignment(IArrayType type) {
IValue value = type.getSize();
if (value == null)
return null;
Number numElements = value.numberValue();
if (numElements == null)
return null;
IType elementType = type.getType();
SizeAndAlignment info = sizeAndAlignment(elementType);
if (numElements.longValue() == 1)
return info;
if (info == null)
return null;
return new SizeAndAlignment(info.size * numElements.longValue(), info.alignment);
}
private SizeAndAlignment sizeAndAlignment(ICompositeType type) {
/* TODO(sprigogin): May produce incorrect result for structures containing bit fields.
* Unfortunately widths of bit fields are not preserved in the AST. */
long size = 0;
int maxAlignment = 1;
IField[] fields;
if (type instanceof ICPPClassType) {
ICPPClassType classType = (ICPPClassType) type;
for (ICPPBase base : ClassTypeHelper.getBases(classType, ast)) {
if (base.isVirtual())
return null; // Don't know how to calculate size when there are virtual bases.
IBinding baseClass = base.getBaseClass();
if (!(baseClass instanceof IType))
return null;
SizeAndAlignment info = sizeAndAlignment((IType) baseClass);
if (info == null)
return null;
size += info.alignment - (size - 1) % info.alignment - 1 + info.size;
if (maxAlignment < info.alignment)
maxAlignment = info.alignment;
for (ICPPMethod method : ClassTypeHelper.getDeclaredMethods(classType, ast)) {
if (method.isVirtual()) {
// Don't know how to calculate size when there are virtual functions.
return null;
}
}
}
fields = ClassTypeHelper.getDeclaredFields(classType, ast);
} else {
fields = type.getFields();
}
boolean union = type.getKey() == ICompositeType.k_union;
for (IField field : fields) {
if (field.isStatic())
continue;
IType fieldType = field.getType();
SizeAndAlignment info;
// sizeof() on a reference type returns the size of the referenced type.
// However, a reference field in a structure only occupies as much space
// as a pointer.
if (fieldType instanceof ICPPReferenceType) {
info = sizeof_pointer;
} else {
info = sizeAndAlignment(fieldType);
}
if (info == null)
return null;
if (union) {
if (size < info.size)
size = info.size;
} else {
if (size > 0)
size += info.alignment - (size - 1) % info.alignment - 1;
size += info.size;
}
if (maxAlignment < info.alignment)
maxAlignment = info.alignment;
}
if (size == 0) // a structure cannot have size 0
size = 1;
size += maxAlignment - (size - 1) % maxAlignment - 1;
return new SizeAndAlignment(size, maxAlignment);
}
private static SizeAndAlignment getSize(Map<String, String> macros, String name,
int maxAlignment) {
String value = macros.get(name);
if (value == null)
return null;
try {
int size = Integer.parseInt(value);
return new SizeAndAlignment(size, Math.min(size, maxAlignment));
} catch (NumberFormatException e) {
return null;
}
}
private SizeAndAlignment getSizeOfPair(SizeAndAlignment sizeAndAlignment) {
return sizeAndAlignment == null ?
null : new SizeAndAlignment(sizeAndAlignment.size * 2, sizeAndAlignment.alignment);
}
}