JDK14/Java14源码在线阅读
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#ifndef SHARE_RUNTIME_SIGNATURE_HPP
#define SHARE_RUNTIME_SIGNATURE_HPP
#include "memory/allocation.hpp"
#include "oops/method.hpp"
// SignatureIterators iterate over a Java signature (or parts of it).
// (Syntax according to: "The Java Virtual Machine Specification" by
// Tim Lindholm & Frank Yellin; section 4.3 Descriptors; p. 89ff.)
//
// Example: Iterating over ([Lfoo;D)I using
// 0123456789
//
// iterate_parameters() calls: do_array(2, 7); do_double();
// iterate_returntype() calls: do_int();
// iterate() calls: do_array(2, 7); do_double(); do_int();
//
// is_return_type() is: false ; false ; true
//
// NOTE: The new optimizer has an alternate, for-loop based signature
// iterator implemented in opto/type.cpp, TypeTuple::make().
class SignatureIterator: public ResourceObj {
protected:
Symbol* _signature; // the signature to iterate over
int _index; // the current character index (only valid during iteration)
int _parameter_index; // the current parameter index (0 outside iteration phase)
BasicType _return_type;
void expect(char c);
int parse_type(); // returns the parameter size in words (0 for void)
void check_signature_end();
public:
// Definitions used in generating and iterating the
// bit field form of the signature generated by the
// Fingerprinter.
enum {
static_feature_size = 1,
is_static_bit = 1,
result_feature_size = 4,
result_feature_mask = 0xF,
parameter_feature_size = 4,
parameter_feature_mask = 0xF,
bool_parm = 1,
byte_parm = 2,
char_parm = 3,
short_parm = 4,
int_parm = 5,
long_parm = 6,
float_parm = 7,
double_parm = 8,
obj_parm = 9,
done_parm = 10, // marker for end of parameters
// max parameters is wordsize minus
// The sign bit, termination field, the result and static bit fields
max_size_of_parameters = (BitsPerLong-1 -
result_feature_size - parameter_feature_size -
static_feature_size) / parameter_feature_size
};
// Constructors
SignatureIterator(Symbol* signature);
// Iteration
void iterate_parameters(); // iterates over parameters only
void iterate_parameters( uint64_t fingerprint );
void iterate_returntype(); // iterates over returntype only
void iterate(); // iterates over whole signature
// Returns the word index of the current parameter;
int parameter_index() const { return _parameter_index; }
bool is_return_type() const { return parameter_index() < 0; }
BasicType get_ret_type() const { return _return_type; }
// Basic types
virtual void do_bool () = 0;
virtual void do_char () = 0;
virtual void do_float () = 0;
virtual void do_double() = 0;
virtual void do_byte () = 0;
virtual void do_short () = 0;
virtual void do_int () = 0;
virtual void do_long () = 0;
virtual void do_void () = 0;
// Object types (begin indexes the first character of the entry, end indexes the first character after the entry)
virtual void do_object(int begin, int end) = 0;
virtual void do_array (int begin, int end) = 0;
static bool is_static(uint64_t fingerprint) {
assert(fingerprint != (uint64_t)CONST64(-1), "invalid fingerprint");
return fingerprint & is_static_bit;
}
static BasicType return_type(uint64_t fingerprint) {
assert(fingerprint != (uint64_t)CONST64(-1), "invalid fingerprint");
return (BasicType) ((fingerprint >> static_feature_size) & result_feature_mask);
}
};
// Specialized SignatureIterators: Used to compute signature specific values.
class SignatureTypeNames : public SignatureIterator {
protected:
virtual void type_name(const char* name) = 0;
void do_bool() { type_name("jboolean"); }
void do_char() { type_name("jchar" ); }
void do_float() { type_name("jfloat" ); }
void do_double() { type_name("jdouble" ); }
void do_byte() { type_name("jbyte" ); }
void do_short() { type_name("jshort" ); }
void do_int() { type_name("jint" ); }
void do_long() { type_name("jlong" ); }
void do_void() { type_name("void" ); }
void do_object(int begin, int end) { type_name("jobject" ); }
void do_array (int begin, int end) { type_name("jobject" ); }
public:
SignatureTypeNames(Symbol* signature) : SignatureIterator(signature) {}
};
class SignatureInfo: public SignatureIterator {
protected:
bool _has_iterated; // need this because iterate cannot be called in constructor (set is virtual!)
bool _has_iterated_return;
int _size;
void lazy_iterate_parameters() { if (!_has_iterated) { iterate_parameters(); _has_iterated = true; } }
void lazy_iterate_return() { if (!_has_iterated_return) { iterate_returntype(); _has_iterated_return = true; } }
virtual void set(int size, BasicType type) = 0;
void do_bool () { set(T_BOOLEAN_size, T_BOOLEAN); }
void do_char () { set(T_CHAR_size , T_CHAR ); }
void do_float () { set(T_FLOAT_size , T_FLOAT ); }
void do_double() { set(T_DOUBLE_size , T_DOUBLE ); }
void do_byte () { set(T_BYTE_size , T_BYTE ); }
void do_short () { set(T_SHORT_size , T_SHORT ); }
void do_int () { set(T_INT_size , T_INT ); }
void do_long () { set(T_LONG_size , T_LONG ); }
void do_void () { set(T_VOID_size , T_VOID ); }
void do_object(int begin, int end) { set(T_OBJECT_size , T_OBJECT ); }
void do_array (int begin, int end) { set(T_ARRAY_size , T_ARRAY ); }
public:
SignatureInfo(Symbol* signature) : SignatureIterator(signature) {
_has_iterated = _has_iterated_return = false;
_size = 0;
_return_type = T_ILLEGAL;
}
};
// Specialized SignatureIterator: Used to compute the argument size.
class ArgumentSizeComputer: public SignatureInfo {
private:
void set(int size, BasicType type) { _size += size; }
public:
ArgumentSizeComputer(Symbol* signature) : SignatureInfo(signature) {}
int size() { lazy_iterate_parameters(); return _size; }
};
class ArgumentCount: public SignatureInfo {
private:
void set(int size, BasicType type) { _size ++; }
public:
ArgumentCount(Symbol* signature) : SignatureInfo(signature) {}
int size() { lazy_iterate_parameters(); return _size; }
};
// Specialized SignatureIterator: Used to compute the result type.
class ResultTypeFinder: public SignatureInfo {
private:
void set(int size, BasicType type) { _return_type = type; }
public:
BasicType type() { lazy_iterate_return(); return _return_type; }
ResultTypeFinder(Symbol* signature) : SignatureInfo(signature) {}
};
// Fingerprinter computes a unique ID for a given method. The ID
// is a bitvector characterizing the methods signature (incl. the receiver).
class Fingerprinter: public SignatureIterator {
private:
uint64_t _fingerprint;
int _shift_count;
methodHandle mh;
public:
void do_bool() { _fingerprint |= (((uint64_t)bool_parm) << _shift_count); _shift_count += parameter_feature_size; }
void do_char() { _fingerprint |= (((uint64_t)char_parm) << _shift_count); _shift_count += parameter_feature_size; }
void do_byte() { _fingerprint |= (((uint64_t)byte_parm) << _shift_count); _shift_count += parameter_feature_size; }
void do_short() { _fingerprint |= (((uint64_t)short_parm) << _shift_count); _shift_count += parameter_feature_size; }
void do_int() { _fingerprint |= (((uint64_t)int_parm) << _shift_count); _shift_count += parameter_feature_size; }
void do_long() { _fingerprint |= (((uint64_t)long_parm) << _shift_count); _shift_count += parameter_feature_size; }
void do_float() { _fingerprint |= (((uint64_t)float_parm) << _shift_count); _shift_count += parameter_feature_size; }
void do_double() { _fingerprint |= (((uint64_t)double_parm) << _shift_count); _shift_count += parameter_feature_size; }
void do_object(int begin, int end) { _fingerprint |= (((uint64_t)obj_parm) << _shift_count); _shift_count += parameter_feature_size; }
void do_array (int begin, int end) { _fingerprint |= (((uint64_t)obj_parm) << _shift_count); _shift_count += parameter_feature_size; }
void do_void() { ShouldNotReachHere(); }
Fingerprinter(const methodHandle& method) : SignatureIterator(method->signature()) {
mh = method;
_fingerprint = 0;
}
uint64_t fingerprint() {
// See if we fingerprinted this method already
if (mh->constMethod()->fingerprint() != CONST64(0)) {
return mh->constMethod()->fingerprint();
}
if (mh->size_of_parameters() > max_size_of_parameters ) {
_fingerprint = (uint64_t)CONST64(-1);
mh->constMethod()->set_fingerprint(_fingerprint);
return _fingerprint;
}
assert( (int)mh->result_type() <= (int)result_feature_mask, "bad result type");
_fingerprint = mh->result_type();
_fingerprint <<= static_feature_size;
if (mh->is_static()) _fingerprint |= 1;
_shift_count = result_feature_size + static_feature_size;
iterate_parameters();
_fingerprint |= ((uint64_t)done_parm) << _shift_count;// mark end of sig
mh->constMethod()->set_fingerprint(_fingerprint);
return _fingerprint;
}
};
// Specialized SignatureIterator: Used for native call purposes
class NativeSignatureIterator: public SignatureIterator {
private:
methodHandle _method;
// We need separate JNI and Java offset values because in 64 bit mode,
// the argument offsets are not in sync with the Java stack.
// For example a long takes up 1 "C" stack entry but 2 Java stack entries.
int _offset; // The java stack offset
int _prepended; // number of prepended JNI parameters (1 JNIEnv, plus 1 mirror if static)
int _jni_offset; // the current parameter offset, starting with 0
void do_bool () { pass_int(); _jni_offset++; _offset++; }
void do_char () { pass_int(); _jni_offset++; _offset++; }
void do_float () { pass_float(); _jni_offset++; _offset++; }
#ifdef _LP64
void do_double() { pass_double(); _jni_offset++; _offset += 2; }
#else
void do_double() { pass_double(); _jni_offset += 2; _offset += 2; }
#endif
void do_byte () { pass_int(); _jni_offset++; _offset++; }
void do_short () { pass_int(); _jni_offset++; _offset++; }
void do_int () { pass_int(); _jni_offset++; _offset++; }
#ifdef _LP64
void do_long () { pass_long(); _jni_offset++; _offset += 2; }
#else
void do_long () { pass_long(); _jni_offset += 2; _offset += 2; }
#endif
void do_void () { ShouldNotReachHere(); }
void do_object(int begin, int end) { pass_object(); _jni_offset++; _offset++; }
void do_array (int begin, int end) { pass_object(); _jni_offset++; _offset++; }
public:
methodHandle method() const { return _method; }
int offset() const { return _offset; }
int jni_offset() const { return _jni_offset + _prepended; }
// int java_offset() const { return method()->size_of_parameters() - _offset - 1; }
bool is_static() const { return method()->is_static(); }
virtual void pass_int() = 0;
virtual void pass_long() = 0;
virtual void pass_object() = 0;
virtual void pass_float() = 0;
#ifdef _LP64
virtual void pass_double() = 0;
#else
virtual void pass_double() { pass_long(); } // may be same as long
#endif
NativeSignatureIterator(const methodHandle& method) : SignatureIterator(method->signature()) {
_method = method;
_offset = 0;
_jni_offset = 0;
const int JNIEnv_words = 1;
const int mirror_words = 1;
_prepended = !is_static() ? JNIEnv_words : JNIEnv_words + mirror_words;
}
// iterate() calles the 2 virtual methods according to the following invocation syntax:
//
// {pass_int | pass_long | pass_object}
//
// Arguments are handled from left to right (receiver first, if any).
// The offset() values refer to the Java stack offsets but are 0 based and increasing.
// The java_offset() values count down to 0, and refer to the Java TOS.
// The jni_offset() values increase from 1 or 2, and refer to C arguments.
void iterate() { iterate(Fingerprinter(method()).fingerprint());
}
// Optimized path if we have the bitvector form of signature
void iterate( uint64_t fingerprint ) {
if (!is_static()) {
// handle receiver (not handled by iterate because not in signature)
pass_object(); _jni_offset++; _offset++;
}
SignatureIterator::iterate_parameters( fingerprint );
}
};
// Handy stream for iterating over signature
class SignatureStream : public StackObj {
private:
Symbol* _signature;
int _begin;
int _end;
BasicType _type;
bool _at_return_type;
Symbol* _previous_name; // cache the previously looked up symbol to avoid lookups
GrowableArray<Symbol*>* _names; // symbols created while parsing that need to be dereferenced
public:
bool at_return_type() const { return _at_return_type; }
bool is_done() const;
void next_non_primitive(int t);
void next() {
Symbol* sig = _signature;
int len = sig->utf8_length();
if (_end >= len) {
_end = len + 1;
return;
}
_begin = _end;
int t = sig->char_at(_begin);
switch (t) {
case JVM_SIGNATURE_BYTE: _type = T_BYTE; break;
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