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bazel / bazel / 77497410a23bd212e8c3b4e48903d805e7d9097f / . / third_party / ijar / classfile.cc
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// Copyright 2015 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// classfile.cc -- classfile parsing and stripping.
//
// TODO(adonovan) don't pass pointers by reference; this is not
// compatible with Google C++ style.
// See README.txt for details.
//
// For definition of JVM class file format, see:
// Java SE 8 Edition:
// http://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4
#define __STDC_FORMAT_MACROS 1
#define __STDC_LIMIT_MACROS 1
#include <inttypes.h> // for PRIx32
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include "third_party/ijar/common.h"
namespace {
// Converts a value to string.
// Workaround for mingw where std::to_string is not implemented.
// See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52015.
template <typename T>
std::string ToString(const T& value) {
std::ostringstream oss;
oss << value;
return oss.str();
}
} // namespace
namespace devtools_ijar {
// See Table 4.3 in JVM Spec.
enum CONSTANT {
CONSTANT_Class = 7,
CONSTANT_FieldRef = 9,
CONSTANT_Methodref = 10,
CONSTANT_Interfacemethodref = 11,
CONSTANT_String = 8,
CONSTANT_Integer = 3,
CONSTANT_Float = 4,
CONSTANT_Long = 5,
CONSTANT_Double = 6,
CONSTANT_NameAndType = 12,
CONSTANT_Utf8 = 1,
CONSTANT_MethodHandle = 15,
CONSTANT_MethodType = 16,
CONSTANT_InvokeDynamic = 18
};
// See Tables 4.1, 4.4, 4.5 in JVM Spec.
enum ACCESS {
ACC_PUBLIC = 0x0001,
ACC_PRIVATE = 0x0002,
ACC_PROTECTED = 0x0004,
ACC_STATIC = 0x0008,
ACC_FINAL = 0x0010,
ACC_SYNCHRONIZED = 0x0020,
ACC_BRIDGE = 0x0040,
ACC_VOLATILE = 0x0040,
ACC_TRANSIENT = 0x0080,
ACC_INTERFACE = 0x0200,
ACC_ABSTRACT = 0x0400,
ACC_SYNTHETIC = 0x1000
};
// See Table 4.7.20-A in Java 8 JVM Spec.
enum TARGET_TYPE {
// Targets for type parameter declarations (ElementType.TYPE_PARAMETER):
CLASS_TYPE_PARAMETER = 0x00,
METHOD_TYPE_PARAMETER = 0x01,
// Targets for type uses that may be externally visible in classes and members
// (ElementType.TYPE_USE):
CLASS_EXTENDS = 0x10,
CLASS_TYPE_PARAMETER_BOUND = 0x11,
METHOD_TYPE_PARAMETER_BOUND = 0x12,
FIELD = 0x13,
METHOD_RETURN = 0x14,
METHOD_RECEIVER = 0x15,
METHOD_FORMAL_PARAMETER = 0x16,
THROWS = 0x17,
// TARGET_TYPE >= 0x40 is reserved for type uses that occur only within code
// blocks. Ijar doesn't need to know about these.
};
struct Constant;
// TODO(adonovan) these globals are unfortunate
static std::vector<Constant*> const_pool_in; // input constant pool
static std::vector<Constant*> const_pool_out; // output constant_pool
static std::set<std::string> used_class_names;
static Constant * class_name;
// Returns the Constant object, given an index into the input constant pool.
// Note: constant(0) == NULL; this invariant is exploited by the
// InnerClassesAttribute, inter alia.
inline Constant *constant(int idx) {
if (idx < 0 || (unsigned)idx >= const_pool_in.size()) {
fprintf(stderr, "Illegal constant pool index: %d\n", idx);
abort();
}
return const_pool_in[idx];
}
/**********************************************************************
* *
* Constants *
* *
**********************************************************************/
// See sec.4.4 of JVM spec.
struct Constant {
Constant(u1 tag) :
slot_(0),
tag_(tag) {}
virtual ~Constant() {}
// For UTF-8 string constants, returns the encoded string.
// Otherwise, returns an undefined string value suitable for debugging.
virtual std::string Display() = 0;
virtual void Write(u1 *&p) = 0;
// Called by slot() when a constant has been identified as required
// in the output classfile's constant pool. This is a hook allowing
// constants to register their dependency on other constants, by
// calling slot() on them in turn.
virtual void Keep() {}
bool Kept() {
return slot_ != 0;
}
// Returns the index of this constant in the output class's constant
// pool, assigning a slot if not already done.
u2 slot() {
if (slot_ == 0) {
Keep();
slot_ = const_pool_out.size(); // BugBot's "narrowing" warning
// is bogus. The number of
// output constants can't exceed
// the number of input constants.
if (slot_ == 0) {
fprintf(stderr, "Constant::slot() called before output phase.\n");
abort();
}
const_pool_out.push_back(this);
if (tag_ == CONSTANT_Long || tag_ == CONSTANT_Double) {
const_pool_out.push_back(NULL);
}
}
return slot_;
}
u2 slot_; // zero => "this constant is unreachable garbage"
u1 tag_;
};
// Extracts class names from a signature and puts them into the global
// variable used_class_names.
//
// desc: the descriptor class names should be extracted from.
// p: the position where the extraction should tart.
void ExtractClassNames(const std::string& desc, size_t* p);
// See sec.4.4.1 of JVM spec.
struct Constant_Class : Constant
{
Constant_Class(u2 name_index) :
Constant(CONSTANT_Class),
name_index_(name_index) {}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, constant(name_index_)->slot());
}
std::string Display() {
return constant(name_index_)->Display();
}
void Keep() { constant(name_index_)->slot(); }
u2 name_index_;
};
// See sec.4.4.2 of JVM spec.
struct Constant_FMIref : Constant
{
Constant_FMIref(u1 tag,
u2 class_index,
u2 name_type_index) :
Constant(tag),
class_index_(class_index),
name_type_index_(name_type_index) {}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, constant(class_index_)->slot());
put_u2be(p, constant(name_type_index_)->slot());
}
std::string Display() {
return constant(class_index_)->Display() + "::" +
constant(name_type_index_)->Display();
}
void Keep() {
constant(class_index_)->slot();
constant(name_type_index_)->slot();
}
u2 class_index_;
u2 name_type_index_;
};
// See sec.4.4.3 of JVM spec.
struct Constant_String : Constant
{
Constant_String(u2 string_index) :
Constant(CONSTANT_String),
string_index_(string_index) {}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, constant(string_index_)->slot());
}
std::string Display() {
return "\"" + constant(string_index_)->Display() + "\"";
}
void Keep() { constant(string_index_)->slot(); }
u2 string_index_;
};
// See sec.4.4.4 of JVM spec.
struct Constant_IntegerOrFloat : Constant
{
Constant_IntegerOrFloat(u1 tag, u4 bytes) :
Constant(tag),
bytes_(bytes) {}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u4be(p, bytes_);
}
std::string Display() { return "int/float"; }
u4 bytes_;
};
// See sec.4.4.5 of JVM spec.
struct Constant_LongOrDouble : Constant_IntegerOrFloat
{
Constant_LongOrDouble(u1 tag, u4 high_bytes, u4 low_bytes) :
Constant_IntegerOrFloat(tag, high_bytes),
low_bytes_(low_bytes) {}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u4be(p, bytes_);
put_u4be(p, low_bytes_);
}
std::string Display() { return "long/double"; }
u4 low_bytes_;
};
// See sec.4.4.6 of JVM spec.
struct Constant_NameAndType : Constant
{
Constant_NameAndType(u2 name_index, u2 descr_index) :
Constant(CONSTANT_NameAndType),
name_index_(name_index),
descr_index_(descr_index) {}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, constant(name_index_)->slot());
put_u2be(p, constant(descr_index_)->slot());
}
std::string Display() {
return constant(name_index_)->Display() + "::" +
constant(descr_index_)->Display();
}
void Keep() {
constant(name_index_)->slot();
constant(descr_index_)->slot();
}
u2 name_index_;
u2 descr_index_;
};
// See sec.4.4.7 of JVM spec.
struct Constant_Utf8 : Constant
{
Constant_Utf8(u4 length, const u1 *utf8) :
Constant(CONSTANT_Utf8),
length_(length),
utf8_(utf8) {}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, length_);
put_n(p, utf8_, length_);
}
std::string Display() {
return std::string((const char*) utf8_, length_);
}
u4 length_;
const u1 *utf8_;
};
// See sec.4.4.8 of JVM spec.
struct Constant_MethodHandle : Constant
{
Constant_MethodHandle(u1 reference_kind, u2 reference_index) :
Constant(CONSTANT_MethodHandle),
reference_kind_(reference_kind),
reference_index_(reference_index) {}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u1(p, reference_kind_);
put_u2be(p, reference_index_);
}
std::string Display() {
return "Constant_MethodHandle::" + ToString(reference_kind_) + "::"
+ constant(reference_index_)->Display();
}
u1 reference_kind_;
u2 reference_index_;
};
// See sec.4.4.9 of JVM spec.
struct Constant_MethodType : Constant
{
Constant_MethodType(u2 descriptor_index) :
Constant(CONSTANT_MethodType),
descriptor_index_(descriptor_index) {}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, descriptor_index_);
}
std::string Display() {
return "Constant_MethodType::" + constant(descriptor_index_)->Display();
}
u2 descriptor_index_;
};
// See sec.4.4.10 of JVM spec.
struct Constant_InvokeDynamic : Constant
{
Constant_InvokeDynamic(u2 bootstrap_method_attr_index, u2 name_and_type_index) :
Constant(CONSTANT_InvokeDynamic),
bootstrap_method_attr_index_(bootstrap_method_attr_index),
name_and_type_index_(name_and_type_index) {}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, bootstrap_method_attr_index_);
put_u2be(p, name_and_type_index_);
}
std::string Display() {
return "Constant_InvokeDynamic::"
+ ToString(bootstrap_method_attr_index_) + "::"
+ constant(name_and_type_index_)->Display();
}
u2 bootstrap_method_attr_index_;
u2 name_and_type_index_;
};
/**********************************************************************
* *
* Attributes *
* *
**********************************************************************/
// See sec.4.7 of JVM spec.
struct Attribute {
virtual ~Attribute() {}
virtual void Write(u1 *&p) = 0;
virtual void ExtractClassNames() {}
void WriteProlog(u1 *&p, u2 length) {
put_u2be(p, attribute_name_->slot());
put_u4be(p, length);
}
Constant *attribute_name_;
};
struct KeepForCompileAttribute : Attribute {
void Write(u1 *&p) { WriteProlog(p, 0); }
};
// See sec.4.7.5 of JVM spec.
struct ExceptionsAttribute : Attribute {
static ExceptionsAttribute* Read(const u1 *&p, Constant *attribute_name) {
ExceptionsAttribute *attr = new ExceptionsAttribute;
attr->attribute_name_ = attribute_name;
u2 number_of_exceptions = get_u2be(p);
for (int ii = 0; ii < number_of_exceptions; ++ii) {
attr->exceptions_.push_back(constant(get_u2be(p)));
}
return attr;
}
void Write(u1 *&p) {
WriteProlog(p, exceptions_.size() * 2 + 2);
put_u2be(p, exceptions_.size());
for (size_t ii = 0; ii < exceptions_.size(); ++ii) {
put_u2be(p, exceptions_[ii]->slot());
}
}
std::vector<Constant*> exceptions_;
};
// See sec.4.7.6 of JVM spec.
struct InnerClassesAttribute : Attribute {
struct Entry {
Constant *inner_class_info;
Constant *outer_class_info;
Constant *inner_name;
u2 inner_class_access_flags;
};
virtual ~InnerClassesAttribute() {
for (size_t i = 0; i < entries_.size(); i++) {
delete entries_[i];
}
}
static InnerClassesAttribute* Read(const u1 *&p, Constant *attribute_name) {
InnerClassesAttribute *attr = new InnerClassesAttribute;
attr->attribute_name_ = attribute_name;
u2 number_of_classes = get_u2be(p);
for (int ii = 0; ii < number_of_classes; ++ii) {
Entry *entry = new Entry;
entry->inner_class_info = constant(get_u2be(p));
entry->outer_class_info = constant(get_u2be(p));
entry->inner_name = constant(get_u2be(p));
entry->inner_class_access_flags = get_u2be(p);
attr->entries_.push_back(entry);
}
return attr;
}
void Write(u1 *&p) {
std::set<int> kept_entries;
// We keep an entry if the constant referring to the inner class is already
// kept. Then we mark its outer class and its class name as kept, too, then
// iterate until a fixed point is reached.
int entry_count;
int iteration = 0;
do {
entry_count = kept_entries.size();
for (int i_entry = 0; i_entry < static_cast<int>(entries_.size());
++i_entry) {
Entry* entry = entries_[i_entry];
if (entry->inner_class_info->Kept() ||
used_class_names.find(entry->inner_class_info->Display()) !=
used_class_names.end() ||
entry->outer_class_info == class_name) {
if (entry->inner_name == NULL) {
// JVMS 4.7.6: inner_name_index is zero iff the class is anonymous
continue;
}
kept_entries.insert(i_entry);
// JVMS 4.7.6: outer_class_info_index is zero for top-level classes
if (entry->outer_class_info != NULL) {
entry->outer_class_info->slot();
}
entry->inner_name->slot();
}
}
iteration += 1;
} while (entry_count != static_cast<int>(kept_entries.size()));
if (kept_entries.empty()) {
return;
}
WriteProlog(p, 2 + kept_entries.size() * 8);
put_u2be(p, kept_entries.size());
for (std::set<int>::iterator it = kept_entries.begin();
it != kept_entries.end();
++it) {
Entry *entry = entries_[*it];
put_u2be(p, entry->inner_class_info == NULL
? 0
: entry->inner_class_info->slot());
put_u2be(p, entry->outer_class_info == NULL
? 0
: entry->outer_class_info->slot());
put_u2be(p, entry->inner_name == NULL
? 0
: entry->inner_name->slot());
put_u2be(p, entry->inner_class_access_flags);
}
}
std::vector<Entry*> entries_;
};
// See sec.4.7.7 of JVM spec.
// We preserve EnclosingMethod attributes to be able to identify local and
// anonymous classes. These classes will be stripped of most content, as they
// represent implementation details that shoudn't leak into the ijars. Omitting
// EnclosingMethod attributes can lead to type-checking failures in the presence
// of generics (see b/9070939).
struct EnclosingMethodAttribute : Attribute {
static EnclosingMethodAttribute* Read(const u1 *&p,
Constant *attribute_name) {
EnclosingMethodAttribute *attr = new EnclosingMethodAttribute;
attr->attribute_name_ = attribute_name;
attr->class_ = constant(get_u2be(p));
attr->method_ = constant(get_u2be(p));
return attr;
}
void Write(u1 *&p) {
WriteProlog(p, 4);
put_u2be(p, class_->slot());
put_u2be(p, method_ == NULL ? 0 : method_->slot());
}
Constant *class_;
Constant *method_;
};
// See sec.4.7.16.1 of JVM spec.
// Used by AnnotationDefault and other attributes.
struct ElementValue {
virtual ~ElementValue() {}
virtual void Write(u1 *&p) = 0;
virtual void ExtractClassNames() {}
static ElementValue* Read(const u1 *&p);
u1 tag_;
u4 length_;
};
struct BaseTypeElementValue : ElementValue {
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, const_value_->slot());
}
static BaseTypeElementValue *Read(const u1 *&p) {
BaseTypeElementValue *value = new BaseTypeElementValue;
value->const_value_ = constant(get_u2be(p));
return value;
}
Constant *const_value_;
};
struct EnumTypeElementValue : ElementValue {
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, type_name_->slot());
put_u2be(p, const_name_->slot());
}
static EnumTypeElementValue *Read(const u1 *&p) {
EnumTypeElementValue *value = new EnumTypeElementValue;
value->type_name_ = constant(get_u2be(p));
value->const_name_ = constant(get_u2be(p));
return value;
}
Constant *type_name_;
Constant *const_name_;
};
struct ClassTypeElementValue : ElementValue {
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, class_info_->slot());
}
virtual void ExtractClassNames() {
size_t idx = 0;
devtools_ijar::ExtractClassNames(class_info_->Display(), &idx);
}
static ClassTypeElementValue *Read(const u1 *&p) {
ClassTypeElementValue *value = new ClassTypeElementValue;
value->class_info_ = constant(get_u2be(p));
return value;
}
Constant *class_info_;
};
struct ArrayTypeElementValue : ElementValue {
virtual ~ArrayTypeElementValue() {
for (const auto *value : values_) {
delete value;
}
}
virtual void ExtractClassNames() {
for (auto *value : values_) {
value->ExtractClassNames();
}
}
void Write(u1 *&p) {
put_u1(p, tag_);
put_u2be(p, values_.size());
for (auto *value : values_) {
value->Write(p);
}
}
static ArrayTypeElementValue *Read(const u1 *&p) {
ArrayTypeElementValue *value = new ArrayTypeElementValue;
u2 num_values = get_u2be(p);
for (int ii = 0; ii < num_values; ++ii) {
value->values_.push_back(ElementValue::Read(p));
}
return value;
}
std::vector<ElementValue*> values_;
};
// See sec.4.7.16 of JVM spec.
struct Annotation {
virtual ~Annotation() {
for (size_t i = 0; i < element_value_pairs_.size(); i++) {
delete element_value_pairs_[i]->element_value_;
delete element_value_pairs_[i];
}
}
void ExtractClassNames() {
for (size_t i = 0; i < element_value_pairs_.size(); i++) {
element_value_pairs_[i]->element_value_->ExtractClassNames();
}
}
void Write(u1 *&p) {
put_u2be(p, type_->slot());
put_u2be(p, element_value_pairs_.size());
for (size_t ii = 0; ii < element_value_pairs_.size(); ++ii) {
put_u2be(p, element_value_pairs_[ii]->element_name_->slot());
element_value_pairs_[ii]->element_value_->Write(p);
}
}
static Annotation *Read(const u1 *&p) {
Annotation *value = new Annotation;
value->type_ = constant(get_u2be(p));
u2 num_element_value_pairs = get_u2be(p);
for (int ii = 0; ii < num_element_value_pairs; ++ii) {
ElementValuePair *pair = new ElementValuePair;
pair->element_name_ = constant(get_u2be(p));
pair->element_value_ = ElementValue::Read(p);
value->element_value_pairs_.push_back(pair);
}
return value;
}
Constant *type_;
struct ElementValuePair {
Constant *element_name_;
ElementValue *element_value_;
};
std::vector<ElementValuePair*> element_value_pairs_;
};
// See sec 4.7.20 of Java 8 JVM Spec
//
// Each entry in the annotations table represents a single run-time visible
// annotation on a type used in a declaration or expression. The type_annotation
// structure has the following format:
//
// type_annotation {
// u1 target_type;
// union {
// type_parameter_target;
// supertype_target;
// type_parameter_bound_target;
// empty_target;
// method_formal_parameter_target;
// throws_target;
// localvar_target;
// catch_target;
// offset_target;
// type_argument_target;
// } target_info;
// type_path target_path;
// u2 type_index;
// u2 num_element_value_pairs;
// {
// u2 element_name_index;
// element_value value;
// }
// element_value_pairs[num_element_value_pairs];
// }
//
struct TypeAnnotation {
virtual ~TypeAnnotation() {
delete target_info_;
delete type_path_;
delete annotation_;
}
void ExtractClassNames() {
annotation_->ExtractClassNames();
}
void Write(u1 *&p) {
put_u1(p, target_type_);
target_info_->Write(p);
type_path_->Write(p);
annotation_->Write(p);
}
static TypeAnnotation *Read(const u1 *&p) {
TypeAnnotation *value = new TypeAnnotation;
value->target_type_ = get_u1(p);
value->target_info_ = ReadTargetInfo(p, value->target_type_);
value->type_path_ = TypePath::Read(p);
value->annotation_ = Annotation::Read(p);
return value;
}
struct TargetInfo {
virtual ~TargetInfo() {}
virtual void Write(u1 *&p) = 0;
};
struct TypeParameterTargetInfo : TargetInfo {
void Write(u1 *&p) {
put_u1(p, type_parameter_index_);
}
static TypeParameterTargetInfo *Read(const u1 *&p) {
TypeParameterTargetInfo *value = new TypeParameterTargetInfo;
value->type_parameter_index_ = get_u1(p);
return value;
}
u1 type_parameter_index_;
};
struct ClassExtendsInfo : TargetInfo {
void Write(u1 *&p) {
put_u2be(p, supertype_index_);
}
static ClassExtendsInfo *Read(const u1 *&p) {
ClassExtendsInfo *value = new ClassExtendsInfo;
value->supertype_index_ = get_u2be(p);
return value;
}
u2 supertype_index_;
};
struct TypeParameterBoundInfo : TargetInfo {
void Write(u1 *&p) {
put_u1(p, type_parameter_index_);
put_u1(p, bound_index_);
}
static TypeParameterBoundInfo *Read(const u1 *&p) {
TypeParameterBoundInfo *value = new TypeParameterBoundInfo;
value->type_parameter_index_ = get_u1(p);
value->bound_index_ = get_u1(p);
return value;
}
u1 type_parameter_index_;
u1 bound_index_;
};
struct EmptyInfo : TargetInfo {
void Write(u1 *& /*p*/) {}
static EmptyInfo *Read(const u1 *& /*p*/) { return new EmptyInfo; }
};
struct MethodFormalParameterInfo : TargetInfo {
void Write(u1 *&p) {
put_u1(p, method_formal_parameter_index_);
}
static MethodFormalParameterInfo *Read(const u1 *&p) {
MethodFormalParameterInfo *value = new MethodFormalParameterInfo;
value->method_formal_parameter_index_ = get_u1(p);
return value;
}
u1 method_formal_parameter_index_;
};
struct ThrowsTypeInfo : TargetInfo {
void Write(u1 *&p) {
put_u2be(p, throws_type_index_);
}
static ThrowsTypeInfo *Read(const u1 *&p) {
ThrowsTypeInfo *value = new ThrowsTypeInfo;
value->throws_type_index_ = get_u2be(p);
return value;
}
u2 throws_type_index_;
};
static TargetInfo *ReadTargetInfo(const u1 *&p, u1 target_type) {
switch (target_type) {
case CLASS_TYPE_PARAMETER:
case METHOD_TYPE_PARAMETER:
return TypeParameterTargetInfo::Read(p);
case CLASS_EXTENDS:
return ClassExtendsInfo::Read(p);
case CLASS_TYPE_PARAMETER_BOUND:
case METHOD_TYPE_PARAMETER_BOUND:
return TypeParameterBoundInfo::Read(p);
case FIELD:
case METHOD_RETURN:
case METHOD_RECEIVER:
return new EmptyInfo;
case METHOD_FORMAL_PARAMETER:
return MethodFormalParameterInfo::Read(p);
case THROWS:
return ThrowsTypeInfo::Read(p);
default:
fprintf(stderr, "Illegal type annotation target type: %d\n",
target_type);
abort();
}
}
struct TypePath {
void Write(u1 *&p) {
put_u1(p, path_.size());
for (TypePathEntry entry : path_) {
put_u1(p, entry.type_path_kind_);
put_u1(p, entry.type_argument_index_);
}
}
static TypePath *Read(const u1 *&p) {
TypePath *value = new TypePath;
u1 path_length = get_u1(p);
for (int ii = 0; ii < path_length; ++ii) {
TypePathEntry entry;
entry.type_path_kind_ = get_u1(p);
entry.type_argument_index_ = get_u1(p);
value->path_.push_back(entry);
}
return value;
}
struct TypePathEntry {
u1 type_path_kind_;
u1 type_argument_index_;
};
std::vector<TypePathEntry> path_;
};
u1 target_type_;
TargetInfo *target_info_;
TypePath *type_path_;
Annotation *annotation_;
};
struct AnnotationTypeElementValue : ElementValue {
virtual ~AnnotationTypeElementValue() {
delete annotation_;
}
void Write(u1 *&p) {
put_u1(p, tag_);
annotation_->Write(p);
}
static AnnotationTypeElementValue *Read(const u1 *&p) {
AnnotationTypeElementValue *value = new AnnotationTypeElementValue;
value->annotation_ = Annotation::Read(p);
return value;
}
Annotation *annotation_;
};
ElementValue* ElementValue::Read(const u1 *&p) {
const u1* start = p;
ElementValue *result;
u1 tag = get_u1(p);
if (tag != 0 && strchr("BCDFIJSZs", (char) tag) != NULL) {
result = BaseTypeElementValue::Read(p);
} else if ((char) tag == 'e') {
result = EnumTypeElementValue::Read(p);
} else if ((char) tag == 'c') {
result = ClassTypeElementValue::Read(p);
} else if ((char) tag == '[') {
result = ArrayTypeElementValue::Read(p);
} else if ((char) tag == '@') {
result = AnnotationTypeElementValue::Read(p);
} else {
fprintf(stderr, "Illegal element_value::tag: %d\n", tag);
abort();
}
result->tag_ = tag;
result->length_ = p - start;
return result;
}
// See sec.4.7.20 of JVM spec.
// We preserve AnnotationDefault attributes because they are required
// in order to make use of an annotation in new code.
struct AnnotationDefaultAttribute : Attribute {
virtual ~AnnotationDefaultAttribute() {
delete default_value_;
}
static AnnotationDefaultAttribute* Read(const u1 *&p,
Constant *attribute_name) {
AnnotationDefaultAttribute *attr = new AnnotationDefaultAttribute;
attr->attribute_name_ = attribute_name;
attr->default_value_ = ElementValue::Read(p);
return attr;
}
void Write(u1 *&p) {
WriteProlog(p, default_value_->length_);
default_value_->Write(p);
}
virtual void ExtractClassNames() {
default_value_->ExtractClassNames();
}
ElementValue *default_value_;
};
// See sec.4.7.2 of JVM spec.
// We preserve ConstantValue attributes because they are required for
// compile-time constant propagation.
struct ConstantValueAttribute : Attribute {
static ConstantValueAttribute* Read(const u1 *&p, Constant *attribute_name) {
ConstantValueAttribute *attr = new ConstantValueAttribute;
attr->attribute_name_ = attribute_name;
attr->constantvalue_ = constant(get_u2be(p));
return attr;
}
void Write(u1 *&p) {
WriteProlog(p, 2);
put_u2be(p, constantvalue_->slot());
}
Constant *constantvalue_;
};
// See sec.4.7.9 of JVM spec.
// We preserve Signature attributes because they are required by the
// compiler for type-checking of generics.
struct SignatureAttribute : Attribute {
static SignatureAttribute* Read(const u1 *&p, Constant *attribute_name) {
SignatureAttribute *attr = new SignatureAttribute;
attr->attribute_name_ = attribute_name;
attr->signature_ = constant(get_u2be(p));
return attr;
}
void Write(u1 *&p) {
WriteProlog(p, 2);
put_u2be(p, signature_->slot());
}
virtual void ExtractClassNames() {
size_t signature_idx = 0;
devtools_ijar::ExtractClassNames(signature_->Display(), &signature_idx);
}
Constant *signature_;
};
// See sec.4.7.15 of JVM spec.
// We preserve Deprecated attributes because they are required by the
// compiler to generate warning messages.
struct DeprecatedAttribute : Attribute {
static DeprecatedAttribute *Read(const u1 *& /*p*/,
Constant *attribute_name) {
DeprecatedAttribute *attr = new DeprecatedAttribute;
attr->attribute_name_ = attribute_name;
return attr;
}
void Write(u1 *&p) {
WriteProlog(p, 0);
}
};
// See sec.4.7.16-17 of JVM spec v3. Includes RuntimeVisible and
// RuntimeInvisible.
//
// We preserve all annotations.
struct AnnotationsAttribute : Attribute {
virtual ~AnnotationsAttribute() {
for (size_t i = 0; i < annotations_.size(); i++) {
delete annotations_[i];
}
}
static AnnotationsAttribute* Read(const u1 *&p, Constant *attribute_name) {
AnnotationsAttribute *attr = new AnnotationsAttribute;
attr->attribute_name_ = attribute_name;
u2 num_annotations = get_u2be(p);
for (int ii = 0; ii < num_annotations; ++ii) {
Annotation *annotation = Annotation::Read(p);
attr->annotations_.push_back(annotation);
}
return attr;
}
virtual void ExtractClassNames() {
for (auto *annotation : annotations_) {
annotation->ExtractClassNames();
}
}
void Write(u1 *&p) {
WriteProlog(p, -1);
u1 *payload_start = p - 4;
put_u2be(p, annotations_.size());
for (auto *annotation : annotations_) {
annotation->Write(p);
}
put_u4be(payload_start, p - 4 - payload_start); // backpatch length
}
std::vector<Annotation*> annotations_;
};
// See sec.4.7.18-19 of JVM spec. Includes RuntimeVisible and
// RuntimeInvisible.
//
// We preserve all annotations.
struct ParameterAnnotationsAttribute : Attribute {
static ParameterAnnotationsAttribute* Read(const u1 *&p,
Constant *attribute_name) {
ParameterAnnotationsAttribute *attr = new ParameterAnnotationsAttribute;
attr->attribute_name_ = attribute_name;
u1 num_parameters = get_u1(p);
for (int ii = 0; ii < num_parameters; ++ii) {
std::vector<Annotation*> annotations;
u2 num_annotations = get_u2be(p);
for (int ii = 0; ii < num_annotations; ++ii) {
Annotation *annotation = Annotation::Read(p);
annotations.push_back(annotation);
}
attr->parameter_annotations_.push_back(annotations);
}
return attr;
}
virtual void ExtractClassNames() {
for (size_t i = 0; i < parameter_annotations_.size(); i++) {
const std::vector<Annotation*>& annotations = parameter_annotations_[i];
for (size_t j = 0; j < annotations.size(); j++) {
annotations[j]->ExtractClassNames();
}
}
}
void Write(u1 *&p) {
WriteProlog(p, -1);
u1 *payload_start = p - 4;
put_u1(p, parameter_annotations_.size());
for (size_t ii = 0; ii < parameter_annotations_.size(); ++ii) {
std::vector<Annotation *> &annotations = parameter_annotations_[ii];
put_u2be(p, annotations.size());
for (size_t jj = 0; jj < annotations.size(); ++jj) {
annotations[jj]->Write(p);
}
}
put_u4be(payload_start, p - 4 - payload_start); // backpatch length
}
std::vector<std::vector<Annotation*> > parameter_annotations_;
};
// See sec.4.7.20 of Java 8 JVM spec. Includes RuntimeVisibleTypeAnnotations
// and RuntimeInvisibleTypeAnnotations.
struct TypeAnnotationsAttribute : Attribute {
static TypeAnnotationsAttribute *Read(const u1 *&p, Constant *attribute_name,
u4 /*attribute_length*/) {
auto attr = new TypeAnnotationsAttribute;
attr->attribute_name_ = attribute_name;
u2 num_annotations = get_u2be(p);
for (int ii = 0; ii < num_annotations; ++ii) {
TypeAnnotation *annotation = TypeAnnotation::Read(p);
attr->type_annotations_.push_back(annotation);
}
return attr;
}
virtual void ExtractClassNames() {
for (auto *type_annotation : type_annotations_) {
type_annotation->ExtractClassNames();
}
}
void Write(u1 *&p) {
WriteProlog(p, -1);
u1 *payload_start = p - 4;
put_u2be(p, type_annotations_.size());
for (TypeAnnotation *annotation : type_annotations_) {
annotation->Write(p);
}
put_u4be(payload_start, p - 4 - payload_start); // backpatch length
}
std::vector<TypeAnnotation*> type_annotations_;
};
// See JVMS §4.7.24
struct MethodParametersAttribute : Attribute {
static MethodParametersAttribute *Read(const u1 *&p, Constant *attribute_name,
u4 /*attribute_length*/) {
auto attr = new MethodParametersAttribute;
attr->attribute_name_ = attribute_name;
u1 parameters_count = get_u1(p);
for (int ii = 0; ii < parameters_count; ++ii) {
MethodParameter* parameter = new MethodParameter;
parameter->name_ = constant(get_u2be(p));
parameter->access_flags_ = get_u2be(p);
attr->parameters_.push_back(parameter);
}
return attr;
}
void Write(u1 *&p) {
WriteProlog(p, -1);
u1 *payload_start = p - 4;
put_u1(p, parameters_.size());
for (MethodParameter* parameter : parameters_) {
put_u2be(p, parameter->name_->slot());
put_u2be(p, parameter->access_flags_);
}
put_u4be(payload_start, p - 4 - payload_start); // backpatch length
}
struct MethodParameter {
Constant *name_;
u2 access_flags_;
};
std::vector<MethodParameter*> parameters_;
};
// See JVMS §4.7.28
struct NestHostAttribute : Attribute {
static NestHostAttribute *Read(const u1 *&p, Constant *attribute_name,
u4 /*attribute_length*/) {
auto attr = new NestHostAttribute;
attr->attribute_name_ = attribute_name;
attr->host_class_index_ = constant(get_u2be(p));
return attr;
}
void Write(u1 *&p) {
WriteProlog(p, 2);
put_u2be(p, host_class_index_->slot());
}
Constant *host_class_index_;
};
// See JVMS §4.7.29
struct NestMembersAttribute : Attribute {
static NestMembersAttribute *Read(const u1 *&p, Constant *attribute_name,
u4 /*attribute_length*/) {
auto attr = new NestMembersAttribute;
attr->attribute_name_ = attribute_name;
u2 number_of_classes = get_u2be(p);
for (int ii = 0; ii < number_of_classes; ++ii) {
attr->classes_.push_back(constant(get_u2be(p)));
}
return attr;
}
void Write(u1 *&p) {
WriteProlog(p, classes_.size() * 2 + 2);
put_u2be(p, classes_.size());
for (size_t ii = 0; ii < classes_.size(); ++ii) {
put_u2be(p, classes_[ii]->slot());
}
}
std::vector<Constant *> classes_;
};
struct GeneralAttribute : Attribute {
static GeneralAttribute* Read(const u1 *&p, Constant *attribute_name,
u4 attribute_length) {
auto attr = new GeneralAttribute;
attr->attribute_name_ = attribute_name;
attr->attribute_length_ = attribute_length;
attr->attribute_content_ = p;
p += attribute_length;
return attr;
}
void Write(u1 *&p) {
WriteProlog(p, attribute_length_);
put_n(p, attribute_content_, attribute_length_);
}
u4 attribute_length_;
const u1 *attribute_content_;
};
/**********************************************************************
* *
* ClassFile *
* *
**********************************************************************/
struct HasAttrs {
std::vector<Attribute*> attributes;
void WriteAttrs(u1 *&p);
void ReadAttrs(const u1 *&p);
virtual ~HasAttrs() {
for (const auto *attribute : attributes) {
delete attribute;
}
}
void ExtractClassNames() {
for (auto *attribute : attributes) {
attribute->ExtractClassNames();
}
}
};
// A field or method.
// See sec.4.5 and 4.6 of JVM spec.
struct Member : HasAttrs {
u2 access_flags;
Constant *name;
Constant *descriptor;
static Member* Read(const u1 *&p) {
Member *m = new Member;
m->access_flags = get_u2be(p);
m->name = constant(get_u2be(p));
m->descriptor = constant(get_u2be(p));
m->ReadAttrs(p);
return m;
}
void Write(u1 *&p) {
put_u2be(p, access_flags);
put_u2be(p, name->slot());
put_u2be(p, descriptor->slot());
WriteAttrs(p);
}
};
// See sec.4.1 of JVM spec.
struct ClassFile : HasAttrs {
size_t length;
// Header:
u4 magic;
u2 major;
u2 minor;
// Body:
u2 access_flags;
Constant *this_class;
Constant *super_class;
std::vector<Constant*> interfaces;
std::vector<Member*> fields;
std::vector<Member*> methods;
virtual ~ClassFile() {
for (size_t i = 0; i < fields.size(); i++) {
delete fields[i];
}
for (size_t i = 0; i < methods.size(); i++) {
delete methods[i];
}
// Constants do not need to be deleted; they are owned by the constant pool.
}
void WriteClass(u1 *&p);
bool ReadConstantPool(const u1 *&p);
bool IsExplicitlyKept();
bool IsLocalOrAnonymous();
void WriteHeader(u1 *&p) {
put_u4be(p, magic);
put_u2be(p, major);
put_u2be(p, minor);
put_u2be(p, const_pool_out.size());
for (u2 ii = 1; ii < const_pool_out.size(); ++ii) {
if (const_pool_out[ii] != NULL) { // NB: NULLs appear after long/double.
const_pool_out[ii]->Write(p);
}
}
}
void WriteBody(u1 *&p) {
put_u2be(p, access_flags);
put_u2be(p, this_class->slot());
put_u2be(p, super_class == NULL ? 0 : super_class->slot());
put_u2be(p, interfaces.size());
for (size_t ii = 0; ii < interfaces.size(); ++ii) {
put_u2be(p, interfaces[ii]->slot());
}
put_u2be(p, fields.size());
for (size_t ii = 0; ii < fields.size(); ++ii) {
fields[ii]->Write(p);
}
put_u2be(p, methods.size());
for (size_t ii = 0; ii < methods.size(); ++ii) {
methods[ii]->Write(p);
}
Attribute* inner_classes = NULL;
// Make the inner classes attribute the last, so that it can know which
// constants were needed
for (size_t ii = 0; ii < attributes.size(); ii++) {
if (attributes[ii]->attribute_name_->Display() == "InnerClasses") {
inner_classes = attributes[ii];
attributes.erase(attributes.begin() + ii);
break;
}
}
if (inner_classes != NULL) {
attributes.push_back(inner_classes);
}
WriteAttrs(p);
}
};
void HasAttrs::ReadAttrs(const u1 *&p) {
u2 attributes_count = get_u2be(p);
for (int ii = 0; ii < attributes_count; ii++) {
Constant *attribute_name = constant(get_u2be(p));
u4 attribute_length = get_u4be(p);
std::string attr_name = attribute_name->Display();
if (attr_name == "SourceFile" ||
attr_name == "StackMapTable" ||
attr_name == "LineNumberTable" ||
attr_name == "LocalVariableTable" ||
attr_name == "LocalVariableTypeTable" ||
attr_name == "Code" ||
attr_name == "Synthetic" ||
attr_name == "BootstrapMethods" ||
attr_name == "SourceDebugExtension") {
p += attribute_length; // drop these attributes
} else if (attr_name == "Exceptions") {
attributes.push_back(ExceptionsAttribute::Read(p, attribute_name));
} else if (attr_name == "Signature") {
attributes.push_back(SignatureAttribute::Read(p, attribute_name));
} else if (attr_name == "Deprecated") {
attributes.push_back(DeprecatedAttribute::Read(p, attribute_name));
} else if (attr_name == "EnclosingMethod") {
attributes.push_back(EnclosingMethodAttribute::Read(p, attribute_name));
} else if (attr_name == "InnerClasses") {
// TODO(bazel-team): omit private inner classes
attributes.push_back(InnerClassesAttribute::Read(p, attribute_name));
} else if (attr_name == "AnnotationDefault") {
attributes.push_back(AnnotationDefaultAttribute::Read(p, attribute_name));
} else if (attr_name == "ConstantValue") {
attributes.push_back(ConstantValueAttribute::Read(p, attribute_name));
} else if (attr_name == "RuntimeVisibleAnnotations" ||
attr_name == "RuntimeInvisibleAnnotations") {
attributes.push_back(AnnotationsAttribute::Read(p, attribute_name));
} else if (attr_name == "RuntimeVisibleParameterAnnotations" ||
attr_name == "RuntimeInvisibleParameterAnnotations") {
attributes.push_back(
ParameterAnnotationsAttribute::Read(p, attribute_name));
} else if (attr_name == "Scala" ||
attr_name == "ScalaSig" ||
attr_name == "ScalaInlineInfo") {
// These are opaque blobs, so can be handled with a general
// attribute handler
attributes.push_back(GeneralAttribute::Read(p, attribute_name,
attribute_length));
} else if (attr_name == "RuntimeVisibleTypeAnnotations" ||
attr_name == "RuntimeInvisibleTypeAnnotations") {
attributes.push_back(TypeAnnotationsAttribute::Read(p, attribute_name,
attribute_length));
} else if (attr_name == "MethodParameters") {
attributes.push_back(
MethodParametersAttribute::Read(p, attribute_name, attribute_length));
} else if (attr_name == "NestHost") {
attributes.push_back(
NestHostAttribute::Read(p, attribute_name, attribute_length));
} else if (attr_name == "NestMembers") {
attributes.push_back(
NestMembersAttribute::Read(p, attribute_name, attribute_length));
} else if (attr_name == "com.google.devtools.ijar.KeepForCompile") {
auto attr = new KeepForCompileAttribute;
attr->attribute_name_ = attribute_name;
attributes.push_back(attr);
} else {
// Skip over unknown attributes with a warning. The JVM spec
// says this is ok, so long as we handle the mandatory attributes.
fprintf(stderr, "ijar: skipping unknown attribute: \"%s\".\n",
attr_name.c_str());
p += attribute_length;
}
}
}
void HasAttrs::WriteAttrs(u1 *&p) {
u1* p_size = p;
put_u2be(p, 0);
int n_written_attrs = 0;
for (size_t ii = 0; ii < attributes.size(); ii++) {
u1* before = p;
attributes[ii]->Write(p);
if (p != before) {
n_written_attrs++;
}
}
put_u2be(p_size, n_written_attrs);
}
// See sec.4.4 of JVM spec.
bool ClassFile::ReadConstantPool(const u1 *&p) {
const_pool_in.clear();
const_pool_in.push_back(NULL); // dummy first item
u2 cp_count = get_u2be(p);
for (int ii = 1; ii < cp_count; ++ii) {
u1 tag = get_u1(p);
if (devtools_ijar::verbose) {
fprintf(stderr, "cp[%d/%d] = tag %d\n", ii, cp_count, tag);
}
switch(tag) {
case CONSTANT_Class: {
u2 name_index = get_u2be(p);
const_pool_in.push_back(new Constant_Class(name_index));
break;
}
case CONSTANT_FieldRef:
case CONSTANT_Methodref:
case CONSTANT_Interfacemethodref: {
u2 class_index = get_u2be(p);
u2 nti = get_u2be(p);
const_pool_in.push_back(new Constant_FMIref(tag, class_index, nti));
break;
}
case CONSTANT_String: {
u2 string_index = get_u2be(p);
const_pool_in.push_back(new Constant_String(string_index));
break;
}
case CONSTANT_NameAndType: {
u2 name_index = get_u2be(p);
u2 descriptor_index = get_u2be(p);
const_pool_in.push_back(
new Constant_NameAndType(name_index, descriptor_index));
break;
}
case CONSTANT_Utf8: {
u2 length = get_u2be(p);
if (devtools_ijar::verbose) {
fprintf(stderr, "Utf8: \"%s\" (%d)\n",
std::string((const char*) p, length).c_str(), length);
}
const_pool_in.push_back(new Constant_Utf8(length, p));
p += length;
break;
}
case CONSTANT_Integer:
case CONSTANT_Float: {
u4 bytes = get_u4be(p);
const_pool_in.push_back(new Constant_IntegerOrFloat(tag, bytes));
break;
}
case CONSTANT_Long:
case CONSTANT_Double: {
u4 high_bytes = get_u4be(p);
u4 low_bytes = get_u4be(p);
const_pool_in.push_back(
new Constant_LongOrDouble(tag, high_bytes, low_bytes));
// Longs and doubles occupy two constant pool slots.
// ("In retrospect, making 8-byte constants take two "constant
// pool entries was a poor choice." --JVM Spec.)
const_pool_in.push_back(NULL);
ii++;
break;
}
case CONSTANT_MethodHandle: {
u1 reference_kind = get_u1(p);
u2 reference_index = get_u2be(p);
const_pool_in.push_back(
new Constant_MethodHandle(reference_kind, reference_index));
break;
}
case CONSTANT_MethodType: {
u2 descriptor_index = get_u2be(p);
const_pool_in.push_back(new Constant_MethodType(descriptor_index));
break;
}
case CONSTANT_InvokeDynamic: {
u2 bootstrap_method_attr = get_u2be(p);
u2 name_name_type_index = get_u2be(p);
const_pool_in.push_back(new Constant_InvokeDynamic(
bootstrap_method_attr, name_name_type_index));
break;
}
default: {
fprintf(stderr, "Unknown constant: %02x. Passing class through.\n",
tag);
return false;
}
}
}
return true;
}
bool ClassFile::IsLocalOrAnonymous() {
for (const Attribute *attribute : attributes) {
if (attribute->attribute_name_->Display() == "EnclosingMethod") {
// JVMS 4.7.6: a class must has EnclosingMethod attribute iff it
// represents a local class or an anonymous class
return true;
}
}
return false;
}
static bool HasKeepForCompile(const std::vector<Attribute *> attributes) {
for (const Attribute *attribute : attributes) {
if (attribute->attribute_name_->Display() ==
"com.google.devtools.ijar.KeepForCompile") {
return true;
}
}
return false;
}
bool ClassFile::IsExplicitlyKept() {
if (HasKeepForCompile(attributes)) {
return true;
}
for (const Member *method : methods) {
if (HasKeepForCompile(method->attributes)) {
return true;
}
}
return false;
}
static ClassFile *ReadClass(const void *classdata, size_t length) {
const u1 *p = (u1*) classdata;
ClassFile *clazz = new ClassFile;
clazz->length = length;
clazz->magic = get_u4be(p);
if (clazz->magic != 0xCAFEBABE) {
fprintf(stderr, "Bad magic %" PRIx32 "\n", clazz->magic);
abort();
}
clazz->major = get_u2be(p);
clazz->minor = get_u2be(p);
if (!clazz->ReadConstantPool(p)) {
delete clazz;
return NULL;
}
clazz->access_flags = get_u2be(p);
clazz->this_class = constant(get_u2be(p));
class_name = clazz->this_class;
u2 super_class_id = get_u2be(p);
clazz->super_class = super_class_id == 0 ? NULL : constant(super_class_id);
u2 interfaces_count = get_u2be(p);
for (int ii = 0; ii < interfaces_count; ++ii) {
clazz->interfaces.push_back(constant(get_u2be(p)));
}
u2 fields_count = get_u2be(p);
for (int ii = 0; ii < fields_count; ++ii) {
Member *field = Member::Read(p);
if ((field->access_flags & ACC_PRIVATE) == ACC_PRIVATE) {
// drop private fields
continue;
}
clazz->fields.push_back(field);
}
u2 methods_count = get_u2be(p);
for (int ii = 0; ii < methods_count; ++ii) {
Member *method = Member::Read(p);
if (HasKeepForCompile(method->attributes)) {
// Always keep methods marked as such
clazz->methods.push_back(method);
continue;
}
// drop class initializers
if (method->name->Display() == "<clinit>") continue;
if ((method->access_flags & ACC_PRIVATE) == ACC_PRIVATE) {
// drop private methods
continue;
}
if ((method->access_flags & (ACC_SYNTHETIC | ACC_BRIDGE | ACC_PUBLIC |
ACC_PROTECTED)) == ACC_SYNTHETIC) {
// drop package-private non-bridge synthetic methods, e.g. synthetic
// constructors used to instantiate private nested classes within their
// declaring compilation unit
continue;
}
clazz->methods.push_back(method);
}
clazz->ReadAttrs(p);
return clazz;
}
// In theory, '/' is also reserved, but it's okay if we just parse package
// identifiers as part of the class name. Note that signatures are UTF-8, but
// this works just as well as in plain ASCII.
static const char *SIGNATURE_NON_IDENTIFIER_CHARS = ".;[<>:";
void Expect(const std::string& desc, size_t* p, char expected) {
if (desc[*p] != expected) {
fprintf(stderr, "Expected '%c' in '%s' at %zd in signature\n",
expected, desc.substr(*p).c_str(), *p);
exit(1);
}
*p += 1;
}
// These functions form a crude recursive descent parser for descriptors and
// signatures in class files (see JVM spec 4.3).
//
// This parser is a bit more liberal than the spec, but this should be fine,
// because it accepts all valid class files and croaks only on invalid ones.
void ParseFromClassTypeSignature(const std::string& desc, size_t* p);
void ParseSimpleClassTypeSignature(const std::string& desc, size_t* p);
void ParseClassTypeSignatureSuffix(const std::string& desc, size_t* p);
void ParseIdentifier(const std::string& desc, size_t* p);
void ParseTypeArgumentsOpt(const std::string& desc, size_t* p);
void ParseMethodDescriptor(const std::string& desc, size_t* p);
void ParseClassTypeSignature(const std::string& desc, size_t* p) {
Expect(desc, p, 'L');
ParseSimpleClassTypeSignature(desc, p);
ParseClassTypeSignatureSuffix(desc, p);
Expect(desc, p, ';');
}
void ParseSimpleClassTypeSignature(const std::string& desc, size_t* p) {
ParseIdentifier(desc, p);
ParseTypeArgumentsOpt(desc, p);
}
void ParseClassTypeSignatureSuffix(const std::string& desc, size_t* p) {
while (desc[*p] == '.') {
*p += 1;
ParseSimpleClassTypeSignature(desc, p);
}
}
void ParseIdentifier(const std::string& desc, size_t* p) {
size_t next = desc.find_first_of(SIGNATURE_NON_IDENTIFIER_CHARS, *p);
std::string id = desc.substr(*p, next - *p);
used_class_names.insert(id);
*p = next;
}
void ParseTypeArgumentsOpt(const std::string& desc, size_t* p) {
if (desc[*p] != '<') {
return;
}
*p += 1;
while (desc[*p] != '>') {
switch (desc[*p]) {
case '*':
*p += 1;
break;
case '+':
case '-':
*p += 1;
ExtractClassNames(desc, p);
break;
default:
ExtractClassNames(desc, p);
break;
}
}
*p += 1;
}
void ParseMethodDescriptor(const std::string& desc, size_t* p) {
Expect(desc, p, '(');
while (desc[*p] != ')') {
ExtractClassNames(desc, p);
}
Expect(desc, p, ')');
ExtractClassNames(desc, p);
}
void ParseFormalTypeParameters(const std::string& desc, size_t* p) {
Expect(desc, p, '<');
while (desc[*p] != '>') {
ParseIdentifier(desc, p);
Expect(desc, p, ':');
if (desc[*p] != ':' && desc[*p] != '>') {
ExtractClassNames(desc, p);
}
while (desc[*p] == ':') {
Expect(desc, p, ':');
ExtractClassNames(desc, p);
}
}
Expect(desc, p, '>');
}
void ExtractClassNames(const std::string& desc, size_t* p) {
switch (desc[*p]) {
case '<':
ParseFormalTypeParameters(desc, p);
ExtractClassNames(desc, p);
break;
case 'L':
ParseClassTypeSignature(desc, p);
break;
case '[':
*p += 1;
ExtractClassNames(desc, p);
break;
case 'T':
*p += 1;
ParseIdentifier(desc, p);
Expect(desc, p, ';');
break;
case '(':
ParseMethodDescriptor(desc, p);
break;
case 'B':
case 'C':
case 'D':
case 'F':
case 'I':
case 'J':
case 'S':
case 'Z':
case 'V':
*p += 1;
break;
default:
fprintf(stderr, "Invalid signature %s\n", desc.substr(*p).c_str());
}
}
void ClassFile::WriteClass(u1 *&p) {
used_class_names.clear();
std::vector<Member *> members;
members.insert(members.end(), fields.begin(), fields.end());
members.insert(members.end(), methods.begin(), methods.end());
ExtractClassNames();
for (auto *member : members) {
size_t idx = 0;
devtools_ijar::ExtractClassNames(member->descriptor->Display(), &idx);
member->ExtractClassNames();
}
// We have to write the body out before the header in order to reference
// the essential constants and populate the output constant pool:
u1 *body = new u1[length];
u1 *q = body;
WriteBody(q); // advances q
u4 body_length = q - body;
WriteHeader(p); // advances p
put_n(p, body, body_length);
delete[] body;
}
bool StripClass(u1 *&classdata_out, const u1 *classdata_in, size_t in_length) {
ClassFile *clazz = ReadClass(classdata_in, in_length);
bool keep = true;
if (clazz == NULL || clazz->IsExplicitlyKept()) {
// Class is invalid or kept. Simply copy it to the output and call it a day.
// TODO: If kept, only emit methods marked with KeepForCompile attribute,
// as opposed to the entire type.
put_n(classdata_out, classdata_in, in_length);
} else if (clazz->IsLocalOrAnonymous()) {
keep = false;
} else {
// Constant pool item zero is a dummy entry. Setting it marks the
// beginning of the output phase; calls to Constant::slot() will
// fail if called prior to this.
const_pool_out.push_back(NULL);
clazz->WriteClass(classdata_out);
delete clazz;
}
// Now clean up all the mess we left behind.
for (size_t i = 0; i < const_pool_in.size(); i++) {
delete const_pool_in[i];
}
const_pool_in.clear();
const_pool_out.clear();
return keep;
}
} // namespace devtools_ijar