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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/link.cc | |
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Diffstat (limited to 'libjava/link.cc')
-rw-r--r-- | libjava/link.cc | 2105 |
1 files changed, 2105 insertions, 0 deletions
diff --git a/libjava/link.cc b/libjava/link.cc new file mode 100644 index 000000000..25114085b --- /dev/null +++ b/libjava/link.cc @@ -0,0 +1,2105 @@ +// link.cc - Code for linking and resolving classes and pool entries. + +/* Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 + Free Software Foundation + + This file is part of libgcj. + +This software is copyrighted work licensed under the terms of the +Libgcj License. Please consult the file "LIBGCJ_LICENSE" for +details. */ + +/* Author: Kresten Krab Thorup <krab@gnu.org> */ + +#include <config.h> +#include <platform.h> + +#include <stdio.h> + +#ifdef USE_LIBFFI +#include <ffi.h> +#endif + +#include <java-interp.h> + +// Set GC_DEBUG before including gc.h! +#ifdef LIBGCJ_GC_DEBUG +# define GC_DEBUG +#endif +#include <gc.h> + +#include <jvm.h> +#include <gcj/cni.h> +#include <string.h> +#include <limits.h> +#include <java-cpool.h> +#include <execution.h> +#ifdef INTERPRETER +#include <jvmti.h> +#include "jvmti-int.h" +#endif +#include <java/lang/Class.h> +#include <java/lang/String.h> +#include <java/lang/StringBuffer.h> +#include <java/lang/Thread.h> +#include <java/lang/InternalError.h> +#include <java/lang/VirtualMachineError.h> +#include <java/lang/VerifyError.h> +#include <java/lang/NoSuchFieldError.h> +#include <java/lang/NoSuchMethodError.h> +#include <java/lang/ClassFormatError.h> +#include <java/lang/IllegalAccessError.h> +#include <java/lang/InternalError.h> +#include <java/lang/AbstractMethodError.h> +#include <java/lang/NoClassDefFoundError.h> +#include <java/lang/IncompatibleClassChangeError.h> +#include <java/lang/VerifyError.h> +#include <java/lang/VMClassLoader.h> +#include <java/lang/reflect/Modifier.h> +#include <java/security/CodeSource.h> + +using namespace gcj; + +template<typename T> +struct aligner +{ + char c; + T field; +}; + +#define ALIGNOF(TYPE) (offsetof (aligner<TYPE>, field)) + +// This returns the alignment of a type as it would appear in a +// structure. This can be different from the alignment of the type +// itself. For instance on x86 double is 8-aligned but struct{double} +// is 4-aligned. +int +_Jv_Linker::get_alignment_from_class (jclass klass) +{ + if (klass == JvPrimClass (byte)) + return ALIGNOF (jbyte); + else if (klass == JvPrimClass (short)) + return ALIGNOF (jshort); + else if (klass == JvPrimClass (int)) + return ALIGNOF (jint); + else if (klass == JvPrimClass (long)) + return ALIGNOF (jlong); + else if (klass == JvPrimClass (boolean)) + return ALIGNOF (jboolean); + else if (klass == JvPrimClass (char)) + return ALIGNOF (jchar); + else if (klass == JvPrimClass (float)) + return ALIGNOF (jfloat); + else if (klass == JvPrimClass (double)) + return ALIGNOF (jdouble); + else + return ALIGNOF (jobject); +} + +void +_Jv_Linker::resolve_field (_Jv_Field *field, java::lang::ClassLoader *loader) +{ + if (! field->isResolved ()) + { + _Jv_Utf8Const *sig = (_Jv_Utf8Const *) field->type; + jclass type = _Jv_FindClassFromSignature (sig->chars(), loader); + if (type == NULL) + throw new java::lang::NoClassDefFoundError(field->name->toString()); + field->type = type; + field->flags &= ~_Jv_FIELD_UNRESOLVED_FLAG; + } +} + +// A helper for find_field that knows how to recursively search +// superclasses and interfaces. +_Jv_Field * +_Jv_Linker::find_field_helper (jclass search, _Jv_Utf8Const *name, + _Jv_Utf8Const *type_name, jclass type, + jclass *declarer) +{ + while (search) + { + // From 5.4.3.2. First search class itself. + for (int i = 0; i < search->field_count; ++i) + { + _Jv_Field *field = &search->fields[i]; + if (! _Jv_equalUtf8Consts (field->name, name)) + continue; + + // Checks for the odd situation where we were able to retrieve the + // field's class from signature but the resolution of the field itself + // failed which means a different class was resolved. + if (type != NULL) + { + try + { + resolve_field (field, search->loader); + } + catch (java::lang::Throwable *exc) + { + java::lang::LinkageError *le = new java::lang::LinkageError + (JvNewStringLatin1 + ("field type mismatch with different loaders")); + + le->initCause(exc); + + throw le; + } + } + + // Note that we compare type names and not types. This is + // bizarre, but we do it because we want to find a field + // (and terminate the search) if it has the correct + // descriptor -- but then later reject it if the class + // loader check results in different classes. We can't just + // pass in the descriptor and check that way, because when + // the field is already resolved there is no easy way to + // find its descriptor again. + if ((field->isResolved () + ? _Jv_equalUtf8Classnames (type_name, field->type->name) + : _Jv_equalUtf8Classnames (type_name, + (_Jv_Utf8Const *) field->type))) + { + *declarer = search; + return field; + } + } + + // Next search direct interfaces. + for (int i = 0; i < search->interface_count; ++i) + { + _Jv_Field *result = find_field_helper (search->interfaces[i], name, + type_name, type, declarer); + if (result) + return result; + } + + // Now search superclass. + search = search->superclass; + } + + return NULL; +} + +bool +_Jv_Linker::has_field_p (jclass search, _Jv_Utf8Const *field_name) +{ + for (int i = 0; i < search->field_count; ++i) + { + _Jv_Field *field = &search->fields[i]; + if (_Jv_equalUtf8Consts (field->name, field_name)) + return true; + } + return false; +} + +// Find a field. +// KLASS is the class that is requesting the field. +// OWNER is the class in which the field should be found. +// FIELD_TYPE_NAME is the type descriptor for the field. +// Fill FOUND_CLASS with the address of the class in which the field +// is actually declared. +// This function does the class loader type checks, and +// also access checks. Returns the field, or throws an +// exception on error. +_Jv_Field * +_Jv_Linker::find_field (jclass klass, jclass owner, + jclass *found_class, + _Jv_Utf8Const *field_name, + _Jv_Utf8Const *field_type_name) +{ + // FIXME: this allocates a _Jv_Utf8Const each time. We should make + // it cheaper. + // Note: This call will resolve the primitive type names ("Z", "B", ...) to + // their Java counterparts ("boolean", "byte", ...) if accessed via + // field_type->name later. Using these variants of the type name is in turn + // important for the find_field_helper function. However if the class + // resolution failed then we can only use the already given type name. + jclass field_type + = _Jv_FindClassFromSignatureNoException (field_type_name->chars(), + klass->loader); + + _Jv_Field *the_field + = find_field_helper (owner, field_name, + (field_type + ? field_type->name : + field_type_name ), + field_type, found_class); + + if (the_field == 0) + { + java::lang::StringBuffer *sb = new java::lang::StringBuffer(); + sb->append(JvNewStringLatin1("field ")); + sb->append(owner->getName()); + sb->append(JvNewStringLatin1(".")); + sb->append(_Jv_NewStringUTF(field_name->chars())); + sb->append(JvNewStringLatin1(" was not found.")); + throw new java::lang::NoSuchFieldError (sb->toString()); + } + + // Accept it when the field's class could not be resolved. + if (field_type == NULL) + // Silently ignore that we were not able to retrieve the type to make it + // possible to run code which does not access this field. + return the_field; + + if (_Jv_CheckAccess (klass, *found_class, the_field->flags)) + { + // Note that the field returned by find_field_helper is always + // resolved. However, we still use the constraint mechanism + // because this may affect other lookups. + _Jv_CheckOrCreateLoadingConstraint (field_type, (*found_class)->loader); + } + else + { + java::lang::StringBuffer *sb + = new java::lang::StringBuffer (); + sb->append(klass->getName()); + sb->append(JvNewStringLatin1(": ")); + sb->append((*found_class)->getName()); + sb->append(JvNewStringLatin1(".")); + sb->append(_Jv_NewStringUtf8Const (field_name)); + throw new java::lang::IllegalAccessError(sb->toString()); + } + + return the_field; +} + +// Check loading constraints for method. +void +_Jv_Linker::check_loading_constraints (_Jv_Method *method, jclass self_class, + jclass other_class) +{ + JArray<jclass> *klass_args; + jclass klass_return; + + _Jv_GetTypesFromSignature (method, self_class, &klass_args, &klass_return); + jclass *klass_arg = elements (klass_args); + java::lang::ClassLoader *found_loader = other_class->loader; + + _Jv_CheckOrCreateLoadingConstraint (klass_return, found_loader); + for (int i = 0; i < klass_args->length; i++) + _Jv_CheckOrCreateLoadingConstraint (*(klass_arg++), found_loader); +} + +_Jv_Method * +_Jv_Linker::resolve_method_entry (jclass klass, jclass &found_class, + int class_index, int name_and_type_index, + bool init, bool is_iface) +{ + _Jv_Constants *pool = &klass->constants; + jclass owner = resolve_pool_entry (klass, class_index).clazz; + + if (init && owner != klass) + _Jv_InitClass (owner); + + _Jv_ushort name_index, type_index; + _Jv_loadIndexes (&pool->data[name_and_type_index], + name_index, + type_index); + + _Jv_Utf8Const *method_name = pool->data[name_index].utf8; + _Jv_Utf8Const *method_signature = pool->data[type_index].utf8; + + _Jv_Method *the_method = 0; + found_class = 0; + + // We're going to cache a pointer to the _Jv_Method object + // when we find it. So, to ensure this doesn't get moved from + // beneath us, we first put all the needed Miranda methods + // into the target class. + wait_for_state (klass, JV_STATE_LOADED); + + // First search the class itself. + the_method = search_method_in_class (owner, klass, + method_name, method_signature); + + if (the_method != 0) + { + found_class = owner; + goto end_of_method_search; + } + + // If we are resolving an interface method, search the + // interface's superinterfaces (A superinterface is not an + // interface's superclass - a superinterface is implemented by + // the interface). + if (is_iface) + { + _Jv_ifaces ifaces; + ifaces.count = 0; + ifaces.len = 4; + ifaces.list = (jclass *) _Jv_Malloc (ifaces.len + * sizeof (jclass *)); + + get_interfaces (owner, &ifaces); + + for (int i = 0; i < ifaces.count; i++) + { + jclass cls = ifaces.list[i]; + the_method = search_method_in_class (cls, klass, method_name, + method_signature); + if (the_method != 0) + { + found_class = cls; + break; + } + } + + _Jv_Free (ifaces.list); + + if (the_method != 0) + goto end_of_method_search; + } + + // Finally, search superclasses. + the_method = (search_method_in_superclasses + (owner->getSuperclass (), klass, method_name, + method_signature, &found_class)); + + + end_of_method_search: + if (the_method == 0) + { + java::lang::StringBuffer *sb = new java::lang::StringBuffer(); + sb->append(JvNewStringLatin1("method ")); + sb->append(owner->getName()); + sb->append(JvNewStringLatin1(".")); + sb->append(_Jv_NewStringUTF(method_name->chars())); + sb->append(JvNewStringLatin1(" with signature ")); + sb->append(_Jv_NewStringUTF(method_signature->chars())); + sb->append(JvNewStringLatin1(" was not found.")); + throw new java::lang::NoSuchMethodError (sb->toString()); + } + + // if (found_class->loader != klass->loader), then we must actually + // check that the types of arguments correspond. JVMS 5.4.3.3. + if (found_class->loader != klass->loader) + check_loading_constraints (the_method, klass, found_class); + + return the_method; +} + +_Jv_Mutex_t _Jv_Linker::resolve_mutex; + +void +_Jv_Linker::init (void) +{ + _Jv_MutexInit (&_Jv_Linker::resolve_mutex); +} + +// Locking in resolve_pool_entry is somewhat subtle. Constant +// resolution is idempotent, so it doesn't matter if two threads +// resolve the same entry. However, it is important that we always +// write the resolved flag and the data together, atomically. It is +// also important that we read them atomically. +_Jv_word +_Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy) +{ + using namespace java::lang::reflect; + + if (GC_base (klass) && klass->constants.data + && ! GC_base (klass->constants.data)) + // If a class is heap-allocated but the constant pool is not this + // is a "new ABI" class, i.e. one where the initial constant pool + // is in the read-only data section of an object file. Copy the + // initial constant pool from there to a new heap-allocated pool. + { + jsize count = klass->constants.size; + if (count) + { + _Jv_word* constants + = (_Jv_word*) _Jv_AllocRawObj (count * sizeof (_Jv_word)); + memcpy ((void*)constants, + (void*)klass->constants.data, + count * sizeof (_Jv_word)); + klass->constants.data = constants; + } + } + + _Jv_Constants *pool = &klass->constants; + + jbyte tags; + _Jv_word data; + tags = read_cpool_entry (&data, pool, index); + + if ((tags & JV_CONSTANT_ResolvedFlag) != 0) + return data; + + switch (tags & ~JV_CONSTANT_LazyFlag) + { + case JV_CONSTANT_Class: + { + _Jv_Utf8Const *name = data.utf8; + + jclass found; + if (name->first() == '[') + found = _Jv_FindClassFromSignatureNoException (name->chars(), + klass->loader); + else + found = _Jv_FindClassNoException (name, klass->loader); + + // If the class could not be loaded a phantom class is created. Any + // function that deals with such a class but cannot do something useful + // with it should just throw a NoClassDefFoundError with the class' + // name. + if (! found) + { + if (lazy) + { + found = _Jv_NewClass(name, NULL, NULL); + found->state = JV_STATE_PHANTOM; + tags |= JV_CONSTANT_ResolvedFlag; + data.clazz = found; + break; + } + else + throw new java::lang::NoClassDefFoundError (name->toString()); + } + + // Check accessibility, but first strip array types as + // _Jv_ClassNameSamePackage can't handle arrays. + jclass check; + for (check = found; + check && check->isArray(); + check = check->getComponentType()) + ; + if ((found->accflags & Modifier::PUBLIC) == Modifier::PUBLIC + || (_Jv_ClassNameSamePackage (check->name, + klass->name))) + { + data.clazz = found; + tags |= JV_CONSTANT_ResolvedFlag; + } + else + { + java::lang::StringBuffer *sb = new java::lang::StringBuffer (); + sb->append(klass->getName()); + sb->append(JvNewStringLatin1(" can't access class ")); + sb->append(found->getName()); + throw new java::lang::IllegalAccessError(sb->toString()); + } + } + break; + + case JV_CONSTANT_String: + { + jstring str; + str = _Jv_NewStringUtf8Const (data.utf8); + data.o = str; + tags |= JV_CONSTANT_ResolvedFlag; + } + break; + + case JV_CONSTANT_Fieldref: + { + _Jv_ushort class_index, name_and_type_index; + _Jv_loadIndexes (&data, + class_index, + name_and_type_index); + jclass owner = (resolve_pool_entry (klass, class_index, true)).clazz; + + // If a phantom class was resolved our field reference is + // unusable because of the missing class. + if (owner->state == JV_STATE_PHANTOM) + throw new java::lang::NoClassDefFoundError(owner->getName()); + + // We don't initialize 'owner', but we do make sure that its + // fields exist. + wait_for_state (owner, JV_STATE_PREPARED); + + _Jv_ushort name_index, type_index; + _Jv_loadIndexes (&pool->data[name_and_type_index], + name_index, + type_index); + + _Jv_Utf8Const *field_name = pool->data[name_index].utf8; + _Jv_Utf8Const *field_type_name = pool->data[type_index].utf8; + + jclass found_class = 0; + _Jv_Field *the_field = find_field (klass, owner, + &found_class, + field_name, + field_type_name); + // Initialize the field's declaring class, not its qualifying + // class. + _Jv_InitClass (found_class); + data.field = the_field; + tags |= JV_CONSTANT_ResolvedFlag; + } + break; + + case JV_CONSTANT_Methodref: + case JV_CONSTANT_InterfaceMethodref: + { + _Jv_ushort class_index, name_and_type_index; + _Jv_loadIndexes (&data, + class_index, + name_and_type_index); + + _Jv_Method *the_method; + jclass found_class; + the_method = resolve_method_entry (klass, found_class, + class_index, name_and_type_index, + true, + tags == JV_CONSTANT_InterfaceMethodref); + + data.rmethod + = klass->engine->resolve_method(the_method, + found_class, + ((the_method->accflags + & Modifier::STATIC) != 0)); + tags |= JV_CONSTANT_ResolvedFlag; + } + break; + } + + write_cpool_entry (data, tags, pool, index); + + return data; +} + +// This function is used to lazily locate superclasses and +// superinterfaces. This must be called with the class lock held. +void +_Jv_Linker::resolve_class_ref (jclass klass, jclass *classref) +{ + jclass ret = *classref; + + // If superclass looks like a constant pool entry, resolve it now. + if (ret && (uaddr) ret < (uaddr) klass->constants.size) + { + if (klass->state < JV_STATE_LINKED) + { + _Jv_Utf8Const *name = klass->constants.data[(uaddr) *classref].utf8; + ret = _Jv_FindClass (name, klass->loader); + if (! ret) + { + throw new java::lang::NoClassDefFoundError (name->toString()); + } + } + else + ret = klass->constants.data[(uaddr) classref].clazz; + *classref = ret; + } +} + +// Find a method declared in the cls that is referenced from klass and +// perform access checks if CHECK_PERMS is true. +_Jv_Method * +_Jv_Linker::search_method_in_class (jclass cls, jclass klass, + _Jv_Utf8Const *method_name, + _Jv_Utf8Const *method_signature, + bool check_perms) +{ + using namespace java::lang::reflect; + + for (int i = 0; i < cls->method_count; i++) + { + _Jv_Method *method = &cls->methods[i]; + if ( (!_Jv_equalUtf8Consts (method->name, + method_name)) + || (!_Jv_equalUtf8Consts (method->signature, + method_signature))) + continue; + + if (!check_perms || _Jv_CheckAccess (klass, cls, method->accflags)) + return method; + else + { + java::lang::StringBuffer *sb = new java::lang::StringBuffer(); + sb->append(klass->getName()); + sb->append(JvNewStringLatin1(": ")); + sb->append(cls->getName()); + sb->append(JvNewStringLatin1(".")); + sb->append(_Jv_NewStringUTF(method_name->chars())); + sb->append(_Jv_NewStringUTF(method_signature->chars())); + throw new java::lang::IllegalAccessError (sb->toString()); + } + } + return 0; +} + +// Like search_method_in_class, but work our way up the superclass +// chain. +_Jv_Method * +_Jv_Linker::search_method_in_superclasses (jclass cls, jclass klass, + _Jv_Utf8Const *method_name, + _Jv_Utf8Const *method_signature, + jclass *found_class, bool check_perms) +{ + _Jv_Method *the_method = NULL; + + for ( ; cls != 0; cls = cls->getSuperclass ()) + { + the_method = search_method_in_class (cls, klass, method_name, + method_signature, check_perms); + if (the_method != 0) + { + if (found_class) + *found_class = cls; + break; + } + } + + return the_method; +} + +#define INITIAL_IOFFSETS_LEN 4 +#define INITIAL_IFACES_LEN 4 + +static _Jv_IDispatchTable null_idt = {SHRT_MAX, 0, {}}; + +// Generate tables for constant-time assignment testing and interface +// method lookup. This implements the technique described by Per Bothner +// <per@bothner.com> on the java-discuss mailing list on 1999-09-02: +// http://gcc.gnu.org/ml/java/1999-q3/msg00377.html +void +_Jv_Linker::prepare_constant_time_tables (jclass klass) +{ + if (klass->isPrimitive () || klass->isInterface ()) + return; + + // Short-circuit in case we've been called already. + if ((klass->idt != NULL) || klass->depth != 0) + return; + + // Calculate the class depth and ancestor table. The depth of a class + // is how many "extends" it is removed from Object. Thus the depth of + // java.lang.Object is 0, but the depth of java.io.FilterOutputStream + // is 2. Depth is defined for all regular and array classes, but not + // interfaces or primitive types. + + jclass klass0 = klass; + jboolean has_interfaces = false; + while (klass0 != &java::lang::Object::class$) + { + if (klass0->interface_count) + has_interfaces = true; + klass0 = klass0->superclass; + klass->depth++; + } + + // We do class member testing in constant time by using a small table + // of all the ancestor classes within each class. The first element is + // a pointer to the current class, and the rest are pointers to the + // classes ancestors, ordered from the current class down by decreasing + // depth. We do not include java.lang.Object in the table of ancestors, + // since it is redundant. Note that the classes pointed to by + // 'ancestors' will always be reachable by other paths. + + klass->ancestors = (jclass *) _Jv_AllocBytes (klass->depth + * sizeof (jclass)); + klass0 = klass; + for (int index = 0; index < klass->depth; index++) + { + klass->ancestors[index] = klass0; + klass0 = klass0->superclass; + } + + if ((klass->accflags & java::lang::reflect::Modifier::ABSTRACT) != 0) + return; + + // Optimization: If class implements no interfaces, use a common + // predefined interface table. + if (!has_interfaces) + { + klass->idt = &null_idt; + return; + } + + _Jv_ifaces ifaces; + ifaces.count = 0; + ifaces.len = INITIAL_IFACES_LEN; + ifaces.list = (jclass *) _Jv_Malloc (ifaces.len * sizeof (jclass *)); + + int itable_size = get_interfaces (klass, &ifaces); + + if (ifaces.count > 0) + { + // The classes pointed to by the itable will always be reachable + // via other paths. + int idt_bytes = sizeof (_Jv_IDispatchTable) + (itable_size + * sizeof (void *)); + klass->idt = (_Jv_IDispatchTable *) _Jv_AllocBytes (idt_bytes); + klass->idt->itable_length = itable_size; + + jshort *itable_offsets = + (jshort *) _Jv_Malloc (ifaces.count * sizeof (jshort)); + + generate_itable (klass, &ifaces, itable_offsets); + + jshort cls_iindex = find_iindex (ifaces.list, itable_offsets, + ifaces.count); + + for (int i = 0; i < ifaces.count; i++) + { + ifaces.list[i]->ioffsets[cls_iindex] = itable_offsets[i]; + } + + klass->idt->iindex = cls_iindex; + + _Jv_Free (ifaces.list); + _Jv_Free (itable_offsets); + } + else + { + klass->idt->iindex = SHRT_MAX; + } +} + +// Return index of item in list, or -1 if item is not present. +inline jshort +_Jv_Linker::indexof (void *item, void **list, jshort list_len) +{ + for (int i=0; i < list_len; i++) + { + if (list[i] == item) + return i; + } + return -1; +} + +// Find all unique interfaces directly or indirectly implemented by klass. +// Returns the size of the interface dispatch table (itable) for klass, which +// is the number of unique interfaces plus the total number of methods that +// those interfaces declare. May extend ifaces if required. +jshort +_Jv_Linker::get_interfaces (jclass klass, _Jv_ifaces *ifaces) +{ + jshort result = 0; + + for (int i = 0; i < klass->interface_count; i++) + { + jclass iface = klass->interfaces[i]; + + /* Make sure interface is linked. */ + wait_for_state(iface, JV_STATE_LINKED); + + if (indexof (iface, (void **) ifaces->list, ifaces->count) == -1) + { + if (ifaces->count + 1 >= ifaces->len) + { + /* Resize ifaces list */ + ifaces->len = ifaces->len * 2; + ifaces->list + = (jclass *) _Jv_Realloc (ifaces->list, + ifaces->len * sizeof(jclass)); + } + ifaces->list[ifaces->count] = iface; + ifaces->count++; + + result += get_interfaces (klass->interfaces[i], ifaces); + } + } + + if (klass->isInterface()) + { + // We want to add 1 plus the number of interface methods here. + // But, we take special care to skip <clinit>. + ++result; + for (int i = 0; i < klass->method_count; ++i) + { + if (klass->methods[i].name->first() != '<') + ++result; + } + } + else if (klass->superclass) + result += get_interfaces (klass->superclass, ifaces); + return result; +} + +// Fill out itable in klass, resolving method declarations in each ifaces. +// itable_offsets is filled out with the position of each iface in itable, +// such that itable[itable_offsets[n]] == ifaces.list[n]. +void +_Jv_Linker::generate_itable (jclass klass, _Jv_ifaces *ifaces, + jshort *itable_offsets) +{ + void **itable = klass->idt->itable; + jshort itable_pos = 0; + + for (int i = 0; i < ifaces->count; i++) + { + jclass iface = ifaces->list[i]; + itable_offsets[i] = itable_pos; + itable_pos = append_partial_itable (klass, iface, itable, itable_pos); + + /* Create ioffsets table for iface */ + if (iface->ioffsets == NULL) + { + // The first element of ioffsets is its length (itself included). + jshort *ioffsets = (jshort *) _Jv_AllocBytes (INITIAL_IOFFSETS_LEN + * sizeof (jshort)); + ioffsets[0] = INITIAL_IOFFSETS_LEN; + for (int i = 1; i < INITIAL_IOFFSETS_LEN; i++) + ioffsets[i] = -1; + + iface->ioffsets = ioffsets; + } + } +} + +// Format method name for use in error messages. +jstring +_Jv_GetMethodString (jclass klass, _Jv_Method *meth, + jclass derived) +{ + using namespace java::lang; + StringBuffer *buf = new StringBuffer (klass->name->toString()); + buf->append (jchar ('.')); + buf->append (meth->name->toString()); + buf->append ((jchar) ' '); + buf->append (meth->signature->toString()); + if (derived) + { + buf->append(JvNewStringLatin1(" in ")); + buf->append(derived->name->toString()); + } + return buf->toString(); +} + +void +_Jv_ThrowNoSuchMethodError () +{ + throw new java::lang::NoSuchMethodError; +} + +#if defined USE_LIBFFI && FFI_CLOSURES && defined(INTERPRETER) +// A function whose invocation is prepared using libffi. It gets called +// whenever a static method of a missing class is invoked. The data argument +// holds a reference to a String denoting the missing class. +// The prepared function call is stored in a class' atable. +void +_Jv_ThrowNoClassDefFoundErrorTrampoline(ffi_cif *, + void *, + void **, + void *data) +{ + throw new java::lang::NoClassDefFoundError( + _Jv_NewStringUtf8Const((_Jv_Utf8Const *) data)); +} +#else +// A variant of the NoClassDefFoundError throwing method that can +// be used without libffi. +void +_Jv_ThrowNoClassDefFoundError() +{ + throw new java::lang::NoClassDefFoundError(); +} +#endif + +// Throw a NoSuchFieldError. Called by compiler-generated code when +// an otable entry is zero. OTABLE_INDEX is the index in the caller's +// otable that refers to the missing field. This index may be used to +// print diagnostic information about the field. +void +_Jv_ThrowNoSuchFieldError (int /* otable_index */) +{ + throw new java::lang::NoSuchFieldError; +} + +// This is put in empty vtable slots. +void +_Jv_ThrowAbstractMethodError () +{ + throw new java::lang::AbstractMethodError(); +} + +// Each superinterface of a class (i.e. each interface that the class +// directly or indirectly implements) has a corresponding "Partial +// Interface Dispatch Table" whose size is (number of methods + 1) words. +// The first word is a pointer to the interface (i.e. the java.lang.Class +// instance for that interface). The remaining words are pointers to the +// actual methods that implement the methods declared in the interface, +// in order of declaration. +// +// Append partial interface dispatch table for "iface" to "itable", at +// position itable_pos. +// Returns the offset at which the next partial ITable should be appended. +jshort +_Jv_Linker::append_partial_itable (jclass klass, jclass iface, + void **itable, jshort pos) +{ + using namespace java::lang::reflect; + + itable[pos++] = (void *) iface; + _Jv_Method *meth; + + for (int j=0; j < iface->method_count; j++) + { + // Skip '<clinit>' here. + if (iface->methods[j].name->first() == '<') + continue; + + meth = NULL; + jclass cl; + for (cl = klass; cl; cl = cl->getSuperclass()) + { + meth = _Jv_GetMethodLocal (cl, iface->methods[j].name, + iface->methods[j].signature); + + if (meth) + break; + } + + if (meth) + { + if ((meth->accflags & Modifier::STATIC) != 0) + throw new java::lang::IncompatibleClassChangeError + (_Jv_GetMethodString (klass, meth)); + if ((meth->accflags & Modifier::PUBLIC) == 0) + throw new java::lang::IllegalAccessError + (_Jv_GetMethodString (klass, meth)); + + if ((meth->accflags & Modifier::ABSTRACT) != 0) + itable[pos] = (void *) &_Jv_ThrowAbstractMethodError; + else + itable[pos] = meth->ncode; + + if (cl->loader != iface->loader) + check_loading_constraints (meth, cl, iface); + } + else + { + // The method doesn't exist in klass. Binary compatibility rules + // permit this, so we delay the error until runtime using a pointer + // to a method which throws an exception. + itable[pos] = (void *) _Jv_ThrowNoSuchMethodError; + } + pos++; + } + + return pos; +} + +static _Jv_Mutex_t iindex_mutex; +static bool iindex_mutex_initialized = false; + +// We need to find the correct offset in the Class Interface Dispatch +// Table for a given interface. Once we have that, invoking an interface +// method just requires combining the Method's index in the interface +// (known at compile time) to get the correct method. Doing a type test +// (cast or instanceof) is the same problem: Once we have a possible Partial +// Interface Dispatch Table, we just compare the first element to see if it +// matches the desired interface. So how can we find the correct offset? +// Our solution is to keep a vector of candiate offsets in each interface +// (ioffsets), and in each class we have an index (idt->iindex) used to +// select the correct offset from ioffsets. +// +// Calculate and return iindex for a new class. +// ifaces is a vector of num interfaces that the class implements. +// offsets[j] is the offset in the interface dispatch table for the +// interface corresponding to ifaces[j]. +// May extend the interface ioffsets if required. +jshort +_Jv_Linker::find_iindex (jclass *ifaces, jshort *offsets, jshort num) +{ + int i; + int j; + + // Acquire a global lock to prevent itable corruption in case of multiple + // classes that implement an intersecting set of interfaces being linked + // simultaneously. We can assume that the mutex will be initialized + // single-threaded. + if (! iindex_mutex_initialized) + { + _Jv_MutexInit (&iindex_mutex); + iindex_mutex_initialized = true; + } + + _Jv_MutexLock (&iindex_mutex); + + for (i=1;; i++) /* each potential position in ioffsets */ + { + for (j=0;; j++) /* each iface */ + { + if (j >= num) + goto found; + if (i >= ifaces[j]->ioffsets[0]) + continue; + int ioffset = ifaces[j]->ioffsets[i]; + /* We can potentially share this position with another class. */ + if (ioffset >= 0 && ioffset != offsets[j]) + break; /* Nope. Try next i. */ + } + } + found: + for (j = 0; j < num; j++) + { + int len = ifaces[j]->ioffsets[0]; + if (i >= len) + { + // Resize ioffsets. + int newlen = 2 * len; + if (i >= newlen) + newlen = i + 3; + + jshort *old_ioffsets = ifaces[j]->ioffsets; + jshort *new_ioffsets = (jshort *) _Jv_AllocBytes (newlen + * sizeof(jshort)); + memcpy (&new_ioffsets[1], &old_ioffsets[1], + (len - 1) * sizeof (jshort)); + new_ioffsets[0] = newlen; + + while (len < newlen) + new_ioffsets[len++] = -1; + + ifaces[j]->ioffsets = new_ioffsets; + } + ifaces[j]->ioffsets[i] = offsets[j]; + } + + _Jv_MutexUnlock (&iindex_mutex); + + return i; +} + +#if defined USE_LIBFFI && FFI_CLOSURES && defined(INTERPRETER) +// We use a structure of this type to store the closure that +// represents a missing method. +struct method_closure +{ + // This field must come first, since the address of this field will + // be the same as the address of the overall structure. This is due + // to disabling interior pointers in the GC. + ffi_closure closure; + _Jv_ClosureList list; + ffi_cif cif; + ffi_type *arg_types[1]; +}; + +void * +_Jv_Linker::create_error_method (_Jv_Utf8Const *class_name, jclass klass) +{ + void *code; + method_closure *closure + = (method_closure *)ffi_closure_alloc (sizeof (method_closure), &code); + + closure->arg_types[0] = &ffi_type_void; + + // Initializes the cif and the closure. If that worked the closure + // is returned and can be used as a function pointer in a class' + // atable. + if ( ffi_prep_cif (&closure->cif, + FFI_DEFAULT_ABI, + 1, + &ffi_type_void, + closure->arg_types) == FFI_OK + && ffi_prep_closure_loc (&closure->closure, + &closure->cif, + _Jv_ThrowNoClassDefFoundErrorTrampoline, + class_name, + code) == FFI_OK) + { + closure->list.registerClosure (klass, closure); + return code; + } + else + { + ffi_closure_free (closure); + java::lang::StringBuffer *buffer = new java::lang::StringBuffer(); + buffer->append(JvNewStringLatin1("Error setting up FFI closure" + " for static method of" + " missing class: ")); + buffer->append (_Jv_NewStringUtf8Const(class_name)); + throw new java::lang::InternalError(buffer->toString()); + } +} +#else +void * +_Jv_Linker::create_error_method (_Jv_Utf8Const *, jclass) +{ + // Codepath for platforms which do not support (or want) libffi. + // You have to accept that it is impossible to provide the name + // of the missing class then. + return (void *) _Jv_ThrowNoClassDefFoundError; +} +#endif // USE_LIBFFI && FFI_CLOSURES + +// Functions for indirect dispatch (symbolic virtual binding) support. + +// There are three tables, atable otable and itable. atable is an +// array of addresses, and otable is an array of offsets, and these +// are used for static and virtual members respectively. itable is an +// array of pairs {address, index} where each address is a pointer to +// an interface. + +// {a,o,i}table_syms is an array of _Jv_MethodSymbols. Each such +// symbol is a tuple of {classname, member name, signature}. + +// Set this to true to enable debugging of indirect dispatch tables/linking. +static bool debug_link = false; + +// link_symbol_table() scans these two arrays and fills in the +// corresponding atable and otable with the addresses of static +// members and the offsets of virtual members. + +// The offset (in bytes) for each resolved method or field is placed +// at the corresponding position in the virtual method offset table +// (klass->otable). + +// This must be called while holding the class lock. + +void +_Jv_Linker::link_symbol_table (jclass klass) +{ + int index = 0; + _Jv_MethodSymbol sym; + if (klass->otable == NULL + || klass->otable->state != 0) + goto atable; + + klass->otable->state = 1; + + if (debug_link) + fprintf (stderr, "Fixing up otable in %s:\n", klass->name->chars()); + for (index = 0; + (sym = klass->otable_syms[index]).class_name != NULL; + ++index) + { + jclass target_class = _Jv_FindClass (sym.class_name, klass->loader); + _Jv_Method *meth = NULL; + + _Jv_Utf8Const *signature = sym.signature; + uaddr special; + maybe_adjust_signature (signature, special); + + if (target_class == NULL) + throw new java::lang::NoClassDefFoundError + (_Jv_NewStringUTF (sym.class_name->chars())); + + // We're looking for a field or a method, and we can tell + // which is needed by looking at the signature. + if (signature->first() == '(' && signature->len() >= 2) + { + // Looks like someone is trying to invoke an interface method + if (target_class->isInterface()) + { + using namespace java::lang; + StringBuffer *sb = new StringBuffer(); + sb->append(JvNewStringLatin1("found interface ")); + sb->append(target_class->getName()); + sb->append(JvNewStringLatin1(" when searching for a class")); + throw new VerifyError(sb->toString()); + } + + // If the target class does not have a vtable_method_count yet, + // then we can't tell the offsets for its methods, so we must lay + // it out now. + wait_for_state(target_class, JV_STATE_PREPARED); + + try + { + meth = (search_method_in_superclasses + (target_class, klass, sym.name, signature, + NULL, special == 0)); + } + catch (::java::lang::IllegalAccessError *e) + { + } + + // Every class has a throwNoSuchMethodErrorIndex method that + // it inherits from java.lang.Object. Find its vtable + // offset. + static int throwNoSuchMethodErrorIndex; + if (throwNoSuchMethodErrorIndex == 0) + { + Utf8Const* name + = _Jv_makeUtf8Const ("throwNoSuchMethodError", + strlen ("throwNoSuchMethodError")); + _Jv_Method* meth + = _Jv_LookupDeclaredMethod (&java::lang::Object::class$, + name, gcj::void_signature); + throwNoSuchMethodErrorIndex + = _Jv_VTable::idx_to_offset (meth->index); + } + + // If we don't find a nonstatic method, insert the + // vtable index of Object.throwNoSuchMethodError(). + // This defers the missing method error until an attempt + // is made to execute it. + { + int offset; + + if (meth != NULL) + offset = _Jv_VTable::idx_to_offset (meth->index); + else + offset = throwNoSuchMethodErrorIndex; + + if (offset == -1) + JvFail ("Bad method index"); + JvAssert (meth->index < target_class->vtable_method_count); + + klass->otable->offsets[index] = offset; + } + + if (debug_link) + fprintf (stderr, " offsets[%d] = %d (class %s@%p : %s(%s))\n", + (int)index, + (int)klass->otable->offsets[index], + (const char*)target_class->name->chars(), + target_class, + (const char*)sym.name->chars(), + (const char*)signature->chars()); + continue; + } + + // Try fields. + { + wait_for_state(target_class, JV_STATE_PREPARED); + jclass found_class; + _Jv_Field *the_field = NULL; + try + { + the_field = find_field (klass, target_class, &found_class, + sym.name, signature); + if ((the_field->flags & java::lang::reflect::Modifier::STATIC)) + throw new java::lang::IncompatibleClassChangeError; + else + klass->otable->offsets[index] = the_field->u.boffset; + } + catch (java::lang::NoSuchFieldError *err) + { + klass->otable->offsets[index] = 0; + } + } + } + + atable: + if (klass->atable == NULL || klass->atable->state != 0) + goto itable; + + klass->atable->state = 1; + + for (index = 0; + (sym = klass->atable_syms[index]).class_name != NULL; + ++index) + { + jclass target_class = + _Jv_FindClassNoException (sym.class_name, klass->loader); + + _Jv_Method *meth = NULL; + + _Jv_Utf8Const *signature = sym.signature; + uaddr special; + maybe_adjust_signature (signature, special); + + // ??? Setting this pointer to null will at least get us a + // NullPointerException + klass->atable->addresses[index] = NULL; + + bool use_error_method = false; + + // If the target class is missing we prepare a function call + // that throws a NoClassDefFoundError and store the address of + // that newly prepared method in the atable. The user can run + // code in classes where the missing class is part of the + // execution environment as long as it is never referenced. + if (target_class == NULL) + use_error_method = true; + // We're looking for a static field or a static method, and we + // can tell which is needed by looking at the signature. + else if (signature->first() == '(' && signature->len() >= 2) + { + // If the target class does not have a vtable_method_count yet, + // then we can't tell the offsets for its methods, so we must lay + // it out now. + wait_for_state (target_class, JV_STATE_PREPARED); + + // Interface methods cannot have bodies. + if (target_class->isInterface()) + { + using namespace java::lang; + StringBuffer *sb = new StringBuffer(); + sb->append(JvNewStringLatin1("class ")); + sb->append(target_class->getName()); + sb->append(JvNewStringLatin1(" is an interface: " + "class expected")); + throw new VerifyError(sb->toString()); + } + + try + { + meth = (search_method_in_superclasses + (target_class, klass, sym.name, signature, + NULL, special == 0)); + } + catch (::java::lang::IllegalAccessError *e) + { + } + + if (meth != NULL) + { + if (meth->ncode) // Maybe abstract? + { + klass->atable->addresses[index] = meth->ncode; + if (debug_link) + fprintf (stderr, " addresses[%d] = %p (class %s@%p : %s(%s))\n", + index, + &klass->atable->addresses[index], + (const char*)target_class->name->chars(), + klass, + (const char*)sym.name->chars(), + (const char*)signature->chars()); + } + } + else + use_error_method = true; + + if (use_error_method) + klass->atable->addresses[index] + = create_error_method(sym.class_name, klass); + + continue; + } + + + // Try fields only if the target class exists. + if (target_class != NULL) + { + wait_for_state(target_class, JV_STATE_PREPARED); + jclass found_class; + _Jv_Field *the_field = find_field (klass, target_class, &found_class, + sym.name, signature); + if ((the_field->flags & java::lang::reflect::Modifier::STATIC)) + klass->atable->addresses[index] = the_field->u.addr; + else + throw new java::lang::IncompatibleClassChangeError; + } + } + + itable: + if (klass->itable == NULL + || klass->itable->state != 0) + return; + + klass->itable->state = 1; + + for (index = 0; + (sym = klass->itable_syms[index]).class_name != NULL; + ++index) + { + jclass target_class = _Jv_FindClass (sym.class_name, klass->loader); + + _Jv_Utf8Const *signature = sym.signature; + uaddr special; + maybe_adjust_signature (signature, special); + + jclass cls; + int i; + + wait_for_state(target_class, JV_STATE_LOADED); + bool found = _Jv_getInterfaceMethod (target_class, cls, i, + sym.name, signature); + + if (found) + { + klass->itable->addresses[index * 2] = cls; + klass->itable->addresses[index * 2 + 1] = (void *)(unsigned long) i; + if (debug_link) + { + fprintf (stderr, " interfaces[%d] = %p (interface %s@%p : %s(%s))\n", + index, + klass->itable->addresses[index * 2], + (const char*)cls->name->chars(), + cls, + (const char*)sym.name->chars(), + (const char*)signature->chars()); + fprintf (stderr, " [%d] = offset %d\n", + index + 1, + (int)(unsigned long)klass->itable->addresses[index * 2 + 1]); + } + + } + else + throw new java::lang::IncompatibleClassChangeError; + } + +} + +// For each catch_record in the list of caught classes, fill in the +// address field. +void +_Jv_Linker::link_exception_table (jclass self) +{ + struct _Jv_CatchClass *catch_record = self->catch_classes; + if (!catch_record || catch_record->classname) + return; + catch_record++; + while (catch_record->classname) + { + try + { + jclass target_class + = _Jv_FindClass (catch_record->classname, + self->getClassLoaderInternal ()); + *catch_record->address = target_class; + } + catch (::java::lang::Throwable *t) + { + // FIXME: We need to do something better here. + *catch_record->address = 0; + } + catch_record++; + } + self->catch_classes->classname = (_Jv_Utf8Const *)-1; +} + +// Set itable method indexes for members of interface IFACE. +void +_Jv_Linker::layout_interface_methods (jclass iface) +{ + if (! iface->isInterface()) + return; + + // itable indexes start at 1. + // FIXME: Static initalizers currently get a NULL placeholder entry in the + // itable so they are also assigned an index here. + for (int i = 0; i < iface->method_count; i++) + iface->methods[i].index = i + 1; +} + +// Prepare virtual method declarations in KLASS, and any superclasses +// as required, by determining their vtable index, setting +// method->index, and finally setting the class's vtable_method_count. +// Must be called with the lock for KLASS held. +void +_Jv_Linker::layout_vtable_methods (jclass klass) +{ + if (klass->vtable != NULL || klass->isInterface() + || klass->vtable_method_count != -1) + return; + + jclass superclass = klass->getSuperclass(); + + if (superclass != NULL && superclass->vtable_method_count == -1) + { + JvSynchronize sync (superclass); + layout_vtable_methods (superclass); + } + + int index = (superclass == NULL ? 0 : superclass->vtable_method_count); + + for (int i = 0; i < klass->method_count; ++i) + { + _Jv_Method *meth = &klass->methods[i]; + _Jv_Method *super_meth = NULL; + + if (! _Jv_isVirtualMethod (meth)) + continue; + + if (superclass != NULL) + { + jclass declarer; + super_meth = _Jv_LookupDeclaredMethod (superclass, meth->name, + meth->signature, &declarer); + // See if this method actually overrides the other method + // we've found. + if (super_meth) + { + if (! _Jv_isVirtualMethod (super_meth) + || ! _Jv_CheckAccess (klass, declarer, + super_meth->accflags)) + super_meth = NULL; + else if ((super_meth->accflags + & java::lang::reflect::Modifier::FINAL) != 0) + { + using namespace java::lang; + StringBuffer *sb = new StringBuffer(); + sb->append(JvNewStringLatin1("method ")); + sb->append(_Jv_GetMethodString(klass, meth)); + sb->append(JvNewStringLatin1(" overrides final method ")); + sb->append(_Jv_GetMethodString(declarer, super_meth)); + throw new VerifyError(sb->toString()); + } + else if (declarer->loader != klass->loader) + { + // JVMS 5.4.2. + check_loading_constraints (meth, klass, declarer); + } + } + } + + if (super_meth) + meth->index = super_meth->index; + else + meth->index = index++; + } + + klass->vtable_method_count = index; +} + +// Set entries in VTABLE for virtual methods declared in KLASS. +void +_Jv_Linker::set_vtable_entries (jclass klass, _Jv_VTable *vtable) +{ + for (int i = klass->method_count - 1; i >= 0; i--) + { + using namespace java::lang::reflect; + + _Jv_Method *meth = &klass->methods[i]; + if (meth->index == (_Jv_ushort) -1) + continue; + if ((meth->accflags & Modifier::ABSTRACT)) + // FIXME: it might be nice to have a libffi trampoline here, + // so we could pass in the method name and other information. + vtable->set_method(meth->index, + (void *) &_Jv_ThrowAbstractMethodError); + else + vtable->set_method(meth->index, meth->ncode); + } +} + +// Allocate and lay out the virtual method table for KLASS. This will +// also cause vtables to be generated for any non-abstract +// superclasses, and virtual method layout to occur for any abstract +// superclasses. Must be called with monitor lock for KLASS held. +void +_Jv_Linker::make_vtable (jclass klass) +{ + using namespace java::lang::reflect; + + // If the vtable exists, or for interface classes, do nothing. All + // other classes, including abstract classes, need a vtable. + if (klass->vtable != NULL || klass->isInterface()) + return; + + // Ensure all the `ncode' entries are set. + klass->engine->create_ncode(klass); + + // Class must be laid out before we can create a vtable. + if (klass->vtable_method_count == -1) + layout_vtable_methods (klass); + + // Allocate the new vtable. + _Jv_VTable *vtable = _Jv_VTable::new_vtable (klass->vtable_method_count); + klass->vtable = vtable; + + // Copy the vtable of the closest superclass. + jclass superclass = klass->superclass; + { + JvSynchronize sync (superclass); + make_vtable (superclass); + } + for (int i = 0; i < superclass->vtable_method_count; ++i) + vtable->set_method (i, superclass->vtable->get_method (i)); + + // Set the class pointer and GC descriptor. + vtable->clas = klass; + vtable->gc_descr = _Jv_BuildGCDescr (klass); + + // For each virtual declared in klass, set new vtable entry or + // override an old one. + set_vtable_entries (klass, vtable); + + // Note that we don't check for abstract methods here. We used to, + // but there is a JVMS clarification that indicates that a check + // here would be too eager. And, a simple test case confirms this. +} + +// Lay out the class, allocating space for static fields and computing +// offsets of instance fields. The class lock must be held by the +// caller. +void +_Jv_Linker::ensure_fields_laid_out (jclass klass) +{ + if (klass->size_in_bytes != -1) + return; + + // Compute the alignment for this type by searching through the + // superclasses and finding the maximum required alignment. We + // could consider caching this in the Class. + int max_align = __alignof__ (java::lang::Object); + jclass super = klass->getSuperclass(); + while (super != NULL) + { + // Ensure that our super has its super installed before + // recursing. + wait_for_state(super, JV_STATE_LOADING); + ensure_fields_laid_out(super); + int num = JvNumInstanceFields (super); + _Jv_Field *field = JvGetFirstInstanceField (super); + while (num > 0) + { + int field_align = get_alignment_from_class (field->type); + if (field_align > max_align) + max_align = field_align; + ++field; + --num; + } + super = super->getSuperclass(); + } + + int instance_size; + // This is the size of the 'static' non-reference fields. + int non_reference_size = 0; + // This is the size of the 'static' reference fields. We count + // these separately to make it simpler for the GC to scan them. + int reference_size = 0; + + // Although java.lang.Object is never interpreted, an interface can + // have a null superclass. Note that we have to lay out an + // interface because it might have static fields. + if (klass->superclass) + instance_size = klass->superclass->size(); + else + instance_size = java::lang::Object::class$.size(); + + klass->engine->allocate_field_initializers (klass); + + for (int i = 0; i < klass->field_count; i++) + { + int field_size; + int field_align; + + _Jv_Field *field = &klass->fields[i]; + + if (! field->isRef ()) + { + // It is safe to resolve the field here, since it's a + // primitive class, which does not cause loading to happen. + resolve_field (field, klass->loader); + field_size = field->type->size (); + field_align = get_alignment_from_class (field->type); + } + else + { + field_size = sizeof (jobject); + field_align = __alignof__ (jobject); + } + + field->bsize = field_size; + + if ((field->flags & java::lang::reflect::Modifier::STATIC)) + { + if (field->u.addr == NULL) + { + // This computes an offset into a region we'll allocate + // shortly, and then adds this offset to the start + // address. + if (field->isRef()) + { + reference_size = ROUND (reference_size, field_align); + field->u.boffset = reference_size; + reference_size += field_size; + } + else + { + non_reference_size = ROUND (non_reference_size, field_align); + field->u.boffset = non_reference_size; + non_reference_size += field_size; + } + } + } + else + { + instance_size = ROUND (instance_size, field_align); + field->u.boffset = instance_size; + instance_size += field_size; + if (field_align > max_align) + max_align = field_align; + } + } + + if (reference_size != 0 || non_reference_size != 0) + klass->engine->allocate_static_fields (klass, reference_size, + non_reference_size); + + // Set the instance size for the class. Note that first we round it + // to the alignment required for this object; this keeps us in sync + // with our current ABI. + instance_size = ROUND (instance_size, max_align); + klass->size_in_bytes = instance_size; +} + +// This takes the class to state JV_STATE_LINKED. The class lock must +// be held when calling this. +void +_Jv_Linker::ensure_class_linked (jclass klass) +{ + if (klass->state >= JV_STATE_LINKED) + return; + + int state = klass->state; + try + { + // Short-circuit, so that mutually dependent classes are ok. + klass->state = JV_STATE_LINKED; + + _Jv_Constants *pool = &klass->constants; + + // Compiled classes require that their class constants be + // resolved here. However, interpreted classes need their + // constants to be resolved lazily. If we resolve an + // interpreted class' constants eagerly, we can end up with + // spurious IllegalAccessErrors when the constant pool contains + // a reference to a class we can't access. This can validly + // occur in an obscure case involving the InnerClasses + // attribute. + if (! _Jv_IsInterpretedClass (klass)) + { + // Resolve class constants first, since other constant pool + // entries may rely on these. + for (int index = 1; index < pool->size; ++index) + { + if (pool->tags[index] == JV_CONSTANT_Class) + // Lazily resolve the entries. + resolve_pool_entry (klass, index, true); + } + } + + // Resolve the remaining constant pool entries. + for (int index = 1; index < pool->size; ++index) + { + jbyte tags; + _Jv_word data; + + tags = read_cpool_entry (&data, pool, index); + if (tags == JV_CONSTANT_String) + { + data.o = _Jv_NewStringUtf8Const (data.utf8); + tags |= JV_CONSTANT_ResolvedFlag; + write_cpool_entry (data, tags, pool, index); + } + } + + if (klass->engine->need_resolve_string_fields()) + { + jfieldID f = JvGetFirstStaticField (klass); + for (int n = JvNumStaticFields (klass); n > 0; --n) + { + int mod = f->getModifiers (); + // If we have a static String field with a non-null initial + // value, we know it points to a Utf8Const. + + // Finds out whether we have to initialize a String without the + // need to resolve the field. + if ((f->isResolved() + ? (f->type == &java::lang::String::class$) + : _Jv_equalUtf8Classnames((_Jv_Utf8Const *) f->type, + java::lang::String::class$.name)) + && (mod & java::lang::reflect::Modifier::STATIC) != 0) + { + jstring *strp = (jstring *) f->u.addr; + if (*strp) + *strp = _Jv_NewStringUtf8Const ((_Jv_Utf8Const *) *strp); + } + f = f->getNextField (); + } + } + + klass->notifyAll (); + + _Jv_PushClass (klass); + } + catch (java::lang::Throwable *t) + { + klass->state = state; + throw t; + } +} + +// This ensures that symbolic superclass and superinterface references +// are resolved for the indicated class. This must be called with the +// class lock held. +void +_Jv_Linker::ensure_supers_installed (jclass klass) +{ + resolve_class_ref (klass, &klass->superclass); + // An interface won't have a superclass. + if (klass->superclass) + wait_for_state (klass->superclass, JV_STATE_LOADING); + + for (int i = 0; i < klass->interface_count; ++i) + { + resolve_class_ref (klass, &klass->interfaces[i]); + wait_for_state (klass->interfaces[i], JV_STATE_LOADING); + } +} + +// This adds missing `Miranda methods' to a class. +void +_Jv_Linker::add_miranda_methods (jclass base, jclass iface_class) +{ + // Note that at this point, all our supers, and the supers of all + // our superclasses and superinterfaces, will have been installed. + + for (int i = 0; i < iface_class->interface_count; ++i) + { + jclass interface = iface_class->interfaces[i]; + + for (int j = 0; j < interface->method_count; ++j) + { + _Jv_Method *meth = &interface->methods[j]; + // Don't bother with <clinit>. + if (meth->name->first() == '<') + continue; + _Jv_Method *new_meth = _Jv_LookupDeclaredMethod (base, meth->name, + meth->signature); + if (! new_meth) + { + // We assume that such methods are very unlikely, so we + // just reallocate the method array each time one is + // found. This greatly simplifies the searching -- + // otherwise we have to make sure that each such method + // found is really unique among all superinterfaces. + int new_count = base->method_count + 1; + _Jv_Method *new_m + = (_Jv_Method *) _Jv_AllocRawObj (sizeof (_Jv_Method) + * new_count); + memcpy (new_m, base->methods, + sizeof (_Jv_Method) * base->method_count); + + // Add new method. + new_m[base->method_count] = *meth; + new_m[base->method_count].index = (_Jv_ushort) -1; + new_m[base->method_count].accflags + |= java::lang::reflect::Modifier::INVISIBLE; + + base->methods = new_m; + base->method_count = new_count; + } + } + + wait_for_state (interface, JV_STATE_LOADED); + add_miranda_methods (base, interface); + } +} + +// This ensures that the class' method table is "complete". This must +// be called with the class lock held. +void +_Jv_Linker::ensure_method_table_complete (jclass klass) +{ + if (klass->vtable != NULL) + return; + + // We need our superclass to have its own Miranda methods installed. + if (! klass->isInterface()) + wait_for_state (klass->getSuperclass (), JV_STATE_LOADED); + + // A class might have so-called "Miranda methods". This is a method + // that is declared in an interface and not re-declared in an + // abstract class. Some compilers don't emit declarations for such + // methods in the class; this will give us problems since we expect + // a declaration for any method requiring a vtable entry. We handle + // this here by searching for such methods and constructing new + // internal declarations for them. Note that we do this + // unconditionally, and not just for abstract classes, to correctly + // account for cases where a class is modified to be concrete and + // still incorrectly inherits an abstract method. + int pre_count = klass->method_count; + add_miranda_methods (klass, klass); + + // Let the execution engine know that we've added methods. + if (klass->method_count != pre_count) + klass->engine->post_miranda_hook(klass); +} + +// Verify a class. Must be called with class lock held. +void +_Jv_Linker::verify_class (jclass klass) +{ + klass->engine->verify(klass); +} + +// Check the assertions contained in the type assertion table for KLASS. +// This is the equivilent of bytecode verification for native, BC-ABI code. +void +_Jv_Linker::verify_type_assertions (jclass klass) +{ + if (debug_link) + fprintf (stderr, "Evaluating type assertions for %s:\n", + klass->name->chars()); + + if (klass->assertion_table == NULL) + return; + + for (int i = 0;; i++) + { + int assertion_code = klass->assertion_table[i].assertion_code; + _Jv_Utf8Const *op1 = klass->assertion_table[i].op1; + _Jv_Utf8Const *op2 = klass->assertion_table[i].op2; + + if (assertion_code == JV_ASSERT_END_OF_TABLE) + return; + else if (assertion_code == JV_ASSERT_TYPES_COMPATIBLE) + { + if (debug_link) + { + fprintf (stderr, " code=%i, operand A=%s B=%s\n", + assertion_code, op1->chars(), op2->chars()); + } + + // The operands are class signatures. op1 is the source, + // op2 is the target. + jclass cl1 = _Jv_FindClassFromSignature (op1->chars(), + klass->getClassLoaderInternal()); + jclass cl2 = _Jv_FindClassFromSignature (op2->chars(), + klass->getClassLoaderInternal()); + + // If the class doesn't exist, ignore the assertion. An exception + // will be thrown later if an attempt is made to actually + // instantiate the class. + if (cl1 == NULL || cl2 == NULL) + continue; + + if (! _Jv_IsAssignableFromSlow (cl1, cl2)) + { + jstring s = JvNewStringUTF ("Incompatible types: In class "); + s = s->concat (klass->getName()); + s = s->concat (JvNewStringUTF (": ")); + s = s->concat (cl1->getName()); + s = s->concat (JvNewStringUTF (" is not assignable to ")); + s = s->concat (cl2->getName()); + throw new java::lang::VerifyError (s); + } + } + else if (assertion_code == JV_ASSERT_IS_INSTANTIABLE) + { + // TODO: Implement this. + } + // Unknown assertion codes are ignored, for forwards-compatibility. + } +} + +void +_Jv_Linker::print_class_loaded (jclass klass) +{ + char *codesource = NULL; + if (klass->protectionDomain != NULL) + { + java::security::CodeSource *cs + = klass->protectionDomain->getCodeSource(); + if (cs != NULL) + { + jstring css = cs->toString(); + int len = JvGetStringUTFLength(css); + codesource = (char *) _Jv_AllocBytes(len + 1); + JvGetStringUTFRegion(css, 0, css->length(), codesource); + codesource[len] = '\0'; + } + } + if (codesource == NULL) + codesource = (char *) "<no code source>"; + + const char *abi; + if (_Jv_IsInterpretedClass (klass)) + abi = "bytecode"; + else if (_Jv_IsBinaryCompatibilityABI (klass)) + abi = "BC-compiled"; + else + abi = "pre-compiled"; + + fprintf (stderr, "[Loaded (%s) %s from %s]\n", abi, klass->name->chars(), + codesource); +} + +// FIXME: mention invariants and stuff. +void +_Jv_Linker::wait_for_state (jclass klass, int state) +{ + if (klass->state >= state) + return; + + java::lang::Thread *self = java::lang::Thread::currentThread(); + + { + JvSynchronize sync (klass); + + // This is similar to the strategy for class initialization. If we + // already hold the lock, just leave. + while (klass->state <= state + && klass->thread + && klass->thread != self) + klass->wait (); + + java::lang::Thread *save = klass->thread; + klass->thread = self; + + // Allocate memory for static fields and constants. + if (GC_base (klass) && klass->fields && ! GC_base (klass->fields)) + { + jsize count = klass->field_count; + if (count) + { + _Jv_Field* fields + = (_Jv_Field*) _Jv_AllocRawObj (count * sizeof (_Jv_Field)); + memcpy ((void*)fields, + (void*)klass->fields, + count * sizeof (_Jv_Field)); + klass->fields = fields; + } + } + + // Print some debugging info if requested. Interpreted classes are + // handled in defineclass, so we only need to handle the two + // pre-compiled cases here. + if ((klass->state == JV_STATE_COMPILED + || klass->state == JV_STATE_PRELOADING) + && ! _Jv_IsInterpretedClass (klass)) + { + if (gcj::verbose_class_flag) + print_class_loaded (klass); + ++gcj::loadedClasses; + } + + try + { + if (state >= JV_STATE_LOADING && klass->state < JV_STATE_LOADING) + { + ensure_supers_installed (klass); + klass->set_state(JV_STATE_LOADING); + } + + if (state >= JV_STATE_LOADED && klass->state < JV_STATE_LOADED) + { + ensure_method_table_complete (klass); + klass->set_state(JV_STATE_LOADED); + } + + if (state >= JV_STATE_PREPARED && klass->state < JV_STATE_PREPARED) + { + ensure_fields_laid_out (klass); + make_vtable (klass); + layout_interface_methods (klass); + prepare_constant_time_tables (klass); + klass->set_state(JV_STATE_PREPARED); + } + + if (state >= JV_STATE_LINKED && klass->state < JV_STATE_LINKED) + { + if (gcj::verifyClasses) + verify_class (klass); + + ensure_class_linked (klass); + link_exception_table (klass); + link_symbol_table (klass); + klass->set_state(JV_STATE_LINKED); + } + } + catch (java::lang::Throwable *exc) + { + klass->thread = save; + klass->set_state(JV_STATE_ERROR); + throw exc; + } + + klass->thread = save; + + if (klass->state == JV_STATE_ERROR) + throw new java::lang::LinkageError; + } + +#ifdef INTERPRETER + if (__builtin_expect (klass->state == JV_STATE_LINKED, false) + && state >= JV_STATE_LINKED + && JVMTI_REQUESTED_EVENT (ClassPrepare)) + { + JNIEnv *jni_env = _Jv_GetCurrentJNIEnv (); + _Jv_JVMTI_PostEvent (JVMTI_EVENT_CLASS_PREPARE, self, jni_env, + klass); + } +#endif +} |