Mercurial > hg > graal-compiler
diff src/share/vm/code/relocInfo.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | dc7f315e41f7 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/code/relocInfo.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,1328 @@ +/* + * Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +// Types in this file: +// relocInfo +// One element of an array of halfwords encoding compressed relocations. +// Also, the source of relocation types (relocInfo::oop_type, ...). +// Relocation +// A flyweight object representing a single relocation. +// It is fully unpacked from the compressed relocation array. +// oop_Relocation, ... (subclasses of Relocation) +// The location of some type-specific operations (oop_addr, ...). +// Also, the source of relocation specs (oop_Relocation::spec, ...). +// RelocationHolder +// A ValueObj type which acts as a union holding a Relocation object. +// Represents a relocation spec passed into a CodeBuffer during assembly. +// RelocIterator +// A StackObj which iterates over the relocations associated with +// a range of code addresses. Can be used to operate a copy of code. +// PatchingRelocIterator +// Specialized subtype of RelocIterator which removes breakpoints +// temporarily during iteration, then restores them. +// BoundRelocation +// An _internal_ type shared by packers and unpackers of relocations. +// It pastes together a RelocationHolder with some pointers into +// code and relocInfo streams. + + +// Notes on relocType: +// +// These hold enough information to read or write a value embedded in +// the instructions of an CodeBlob. They're used to update: +// +// 1) embedded oops (isOop() == true) +// 2) inline caches (isIC() == true) +// 3) runtime calls (isRuntimeCall() == true) +// 4) internal word ref (isInternalWord() == true) +// 5) external word ref (isExternalWord() == true) +// +// when objects move (GC) or if code moves (compacting the code heap). +// They are also used to patch the code (if a call site must change) +// +// A relocInfo is represented in 16 bits: +// 4 bits indicating the relocation type +// 12 bits indicating the offset from the previous relocInfo address +// +// The offsets accumulate along the relocInfo stream to encode the +// address within the CodeBlob, which is named RelocIterator::addr(). +// The address of a particular relocInfo always points to the first +// byte of the relevant instruction (and not to any of its subfields +// or embedded immediate constants). +// +// The offset value is scaled appropriately for the target machine. +// (See relocInfo_<arch>.hpp for the offset scaling.) +// +// On some machines, there may also be a "format" field which may provide +// additional information about the format of the instruction stream +// at the corresponding code address. The format value is usually zero. +// Any machine (such as Intel) whose instructions can sometimes contain +// more than one relocatable constant needs format codes to distinguish +// which operand goes with a given relocation. +// +// If the target machine needs N format bits, the offset has 12-N bits, +// the format is encoded between the offset and the type, and the +// relocInfo_<arch>.hpp file has manifest constants for the format codes. +// +// If the type is "data_prefix_tag" then the offset bits are further encoded, +// and in fact represent not a code-stream offset but some inline data. +// The data takes the form of a counted sequence of halfwords, which +// precedes the actual relocation record. (Clients never see it directly.) +// The interpetation of this extra data depends on the relocation type. +// +// On machines that have 32-bit immediate fields, there is usually +// little need for relocation "prefix" data, because the instruction stream +// is a perfectly reasonable place to store the value. On machines in +// which 32-bit values must be "split" across instructions, the relocation +// data is the "true" specification of the value, which is then applied +// to some field of the instruction (22 or 13 bits, on SPARC). +// +// Whenever the location of the CodeBlob changes, any PC-relative +// relocations, and any internal_word_type relocations, must be reapplied. +// After the GC runs, oop_type relocations must be reapplied. +// +// +// Here are meanings of the types: +// +// relocInfo::none -- a filler record +// Value: none +// Instruction: The corresponding code address is ignored +// Data: Any data prefix and format code are ignored +// (This means that any relocInfo can be disabled by setting +// its type to none. See relocInfo::remove.) +// +// relocInfo::oop_type -- a reference to an oop +// Value: an oop, or else the address (handle) of an oop +// Instruction types: memory (load), set (load address) +// Data: [] an oop stored in 4 bytes of instruction +// [n] n is the index of an oop in the CodeBlob's oop pool +// [[N]n l] and l is a byte offset to be applied to the oop +// [Nn Ll] both index and offset may be 32 bits if necessary +// Here is a special hack, used only by the old compiler: +// [[N]n 00] the value is the __address__ of the nth oop in the pool +// (Note that the offset allows optimal references to class variables.) +// +// relocInfo::internal_word_type -- an address within the same CodeBlob +// relocInfo::section_word_type -- same, but can refer to another section +// Value: an address in the CodeBlob's code or constants section +// Instruction types: memory (load), set (load address) +// Data: [] stored in 4 bytes of instruction +// [[L]l] a relative offset (see [About Offsets] below) +// In the case of section_word_type, the offset is relative to a section +// base address, and the section number (e.g., SECT_INSTS) is encoded +// into the low two bits of the offset L. +// +// relocInfo::external_word_type -- a fixed address in the runtime system +// Value: an address +// Instruction types: memory (load), set (load address) +// Data: [] stored in 4 bytes of instruction +// [n] the index of a "well-known" stub (usual case on RISC) +// [Ll] a 32-bit address +// +// relocInfo::runtime_call_type -- a fixed subroutine in the runtime system +// Value: an address +// Instruction types: PC-relative call (or a PC-relative branch) +// Data: [] stored in 4 bytes of instruction +// +// relocInfo::static_call_type -- a static call +// Value: an CodeBlob, a stub, or a fixup routine +// Instruction types: a call +// Data: [] +// The identity of the callee is extracted from debugging information. +// //%note reloc_3 +// +// relocInfo::virtual_call_type -- a virtual call site (which includes an inline +// cache) +// Value: an CodeBlob, a stub, the interpreter, or a fixup routine +// Instruction types: a call, plus some associated set-oop instructions +// Data: [] the associated set-oops are adjacent to the call +// [n] n is a relative offset to the first set-oop +// [[N]n l] and l is a limit within which the set-oops occur +// [Nn Ll] both n and l may be 32 bits if necessary +// The identity of the callee is extracted from debugging information. +// +// relocInfo::opt_virtual_call_type -- a virtual call site that is statically bound +// +// Same info as a static_call_type. We use a special type, so the handling of +// virtuals and statics are separated. +// +// +// The offset n points to the first set-oop. (See [About Offsets] below.) +// In turn, the set-oop instruction specifies or contains an oop cell devoted +// exclusively to the IC call, which can be patched along with the call. +// +// The locations of any other set-oops are found by searching the relocation +// information starting at the first set-oop, and continuing until all +// relocations up through l have been inspected. The value l is another +// relative offset. (Both n and l are relative to the call's first byte.) +// +// The limit l of the search is exclusive. However, if it points within +// the call (e.g., offset zero), it is adjusted to point after the call and +// any associated machine-specific delay slot. +// +// Since the offsets could be as wide as 32-bits, these conventions +// put no restrictions whatever upon code reorganization. +// +// The compiler is responsible for ensuring that transition from a clean +// state to a monomorphic compiled state is MP-safe. This implies that +// the system must respond well to intermediate states where a random +// subset of the set-oops has been correctly from the clean state +// upon entry to the VEP of the compiled method. In the case of a +// machine (Intel) with a single set-oop instruction, the 32-bit +// immediate field must not straddle a unit of memory coherence. +// //%note reloc_3 +// +// relocInfo::breakpoint_type -- a conditional breakpoint in the code +// Value: none +// Instruction types: any whatsoever +// Data: [b [T]t i...] +// The b is a bit-packed word representing the breakpoint's attributes. +// The t is a target address which the breakpoint calls (when it is enabled). +// The i... is a place to store one or two instruction words overwritten +// by a trap, so that the breakpoint may be subsequently removed. +// +// relocInfo::static_stub_type -- an extra stub for each static_call_type +// Value: none +// Instruction types: a virtual call: { set_oop; jump; } +// Data: [[N]n] the offset of the associated static_call reloc +// This stub becomes the target of a static call which must be upgraded +// to a virtual call (because the callee is interpreted). +// See [About Offsets] below. +// //%note reloc_2 +// +// For example: +// +// INSTRUCTIONS RELOC: TYPE PREFIX DATA +// ------------ ---- ----------- +// sethi %hi(myObject), R oop_type [n(myObject)] +// ld [R+%lo(myObject)+fldOffset], R2 oop_type [n(myObject) fldOffset] +// add R2, 1, R2 +// st R2, [R+%lo(myObject)+fldOffset] oop_type [n(myObject) fldOffset] +//%note reloc_1 +// +// This uses 4 instruction words, 8 relocation halfwords, +// and an entry (which is sharable) in the CodeBlob's oop pool, +// for a total of 36 bytes. +// +// Note that the compiler is responsible for ensuring the "fldOffset" when +// added to "%lo(myObject)" does not overflow the immediate fields of the +// memory instructions. +// +// +// [About Offsets] Relative offsets are supplied to this module as +// positive byte offsets, but they may be internally stored scaled +// and/or negated, depending on what is most compact for the target +// system. Since the object pointed to by the offset typically +// precedes the relocation address, it is profitable to store +// these negative offsets as positive numbers, but this decision +// is internal to the relocation information abstractions. +// + +class Relocation; +class CodeBuffer; +class CodeSection; +class RelocIterator; + +class relocInfo VALUE_OBJ_CLASS_SPEC { + friend class RelocIterator; + public: + enum relocType { + none = 0, // Used when no relocation should be generated + oop_type = 1, // embedded oop + virtual_call_type = 2, // a standard inline cache call for a virtual send + opt_virtual_call_type = 3, // a virtual call that has been statically bound (i.e., no IC cache) + static_call_type = 4, // a static send + static_stub_type = 5, // stub-entry for static send (takes care of interpreter case) + runtime_call_type = 6, // call to fixed external routine + external_word_type = 7, // reference to fixed external address + internal_word_type = 8, // reference within the current code blob + section_word_type = 9, // internal, but a cross-section reference + poll_type = 10, // polling instruction for safepoints + poll_return_type = 11, // polling instruction for safepoints at return + breakpoint_type = 12, // an initialization barrier or safepoint + yet_unused_type = 13, // Still unused + yet_unused_type_2 = 14, // Still unused + data_prefix_tag = 15, // tag for a prefix (carries data arguments) + type_mask = 15 // A mask which selects only the above values + }; + + protected: + unsigned short _value; + + enum RawBitsToken { RAW_BITS }; + relocInfo(relocType type, RawBitsToken ignore, int bits) + : _value((type << nontype_width) + bits) { } + + relocInfo(relocType type, RawBitsToken ignore, int off, int f) + : _value((type << nontype_width) + (off / (unsigned)offset_unit) + (f << offset_width)) { } + + public: + // constructor + relocInfo(relocType type, int offset, int format = 0) +#ifndef ASSERT + { + (*this) = relocInfo(type, RAW_BITS, offset, format); + } +#else + // Put a bunch of assertions out-of-line. + ; +#endif + + #define APPLY_TO_RELOCATIONS(visitor) \ + visitor(oop) \ + visitor(virtual_call) \ + visitor(opt_virtual_call) \ + visitor(static_call) \ + visitor(static_stub) \ + visitor(runtime_call) \ + visitor(external_word) \ + visitor(internal_word) \ + visitor(poll) \ + visitor(poll_return) \ + visitor(breakpoint) \ + visitor(section_word) \ + + + public: + enum { + value_width = sizeof(unsigned short) * BitsPerByte, + type_width = 4, // == log2(type_mask+1) + nontype_width = value_width - type_width, + datalen_width = nontype_width-1, + datalen_tag = 1 << datalen_width, // or-ed into _value + datalen_limit = 1 << datalen_width, + datalen_mask = (1 << datalen_width)-1 + }; + + // accessors + public: + relocType type() const { return (relocType)((unsigned)_value >> nontype_width); } + int format() const { return format_mask==0? 0: format_mask & + ((unsigned)_value >> offset_width); } + int addr_offset() const { assert(!is_prefix(), "must have offset"); + return (_value & offset_mask)*offset_unit; } + + protected: + const short* data() const { assert(is_datalen(), "must have data"); + return (const short*)(this + 1); } + int datalen() const { assert(is_datalen(), "must have data"); + return (_value & datalen_mask); } + int immediate() const { assert(is_immediate(), "must have immed"); + return (_value & datalen_mask); } + public: + static int addr_unit() { return offset_unit; } + static int offset_limit() { return (1 << offset_width) * offset_unit; } + + void set_type(relocType type); + void set_format(int format); + + void remove() { set_type(none); } + + protected: + bool is_none() const { return type() == none; } + bool is_prefix() const { return type() == data_prefix_tag; } + bool is_datalen() const { assert(is_prefix(), "must be prefix"); + return (_value & datalen_tag) != 0; } + bool is_immediate() const { assert(is_prefix(), "must be prefix"); + return (_value & datalen_tag) == 0; } + + public: + // Occasionally records of type relocInfo::none will appear in the stream. + // We do not bother to filter these out, but clients should ignore them. + // These records serve as "filler" in three ways: + // - to skip large spans of unrelocated code (this is rare) + // - to pad out the relocInfo array to the required oop alignment + // - to disable old relocation information which is no longer applicable + + inline friend relocInfo filler_relocInfo(); + + // Every non-prefix relocation may be preceded by at most one prefix, + // which supplies 1 or more halfwords of associated data. Conventionally, + // an int is represented by 0, 1, or 2 halfwords, depending on how + // many bits are required to represent the value. (In addition, + // if the sole halfword is a 10-bit unsigned number, it is made + // "immediate" in the prefix header word itself. This optimization + // is invisible outside this module.) + + inline friend relocInfo prefix_relocInfo(int datalen = 0); + + protected: + // an immediate relocInfo optimizes a prefix with one 10-bit unsigned value + static relocInfo immediate_relocInfo(int data0) { + assert(fits_into_immediate(data0), "data0 in limits"); + return relocInfo(relocInfo::data_prefix_tag, RAW_BITS, data0); + } + static bool fits_into_immediate(int data0) { + return (data0 >= 0 && data0 < datalen_limit); + } + + public: + // Support routines for compilers. + + // This routine takes an infant relocInfo (unprefixed) and + // edits in its prefix, if any. It also updates dest.locs_end. + void initialize(CodeSection* dest, Relocation* reloc); + + // This routine updates a prefix and returns the limit pointer. + // It tries to compress the prefix from 32 to 16 bits, and if + // successful returns a reduced "prefix_limit" pointer. + relocInfo* finish_prefix(short* prefix_limit); + + // bit-packers for the data array: + + // As it happens, the bytes within the shorts are ordered natively, + // but the shorts within the word are ordered big-endian. + // This is an arbitrary choice, made this way mainly to ease debugging. + static int data0_from_int(jint x) { return x >> value_width; } + static int data1_from_int(jint x) { return (short)x; } + static jint jint_from_data(short* data) { + return (data[0] << value_width) + (unsigned short)data[1]; + } + + static jint short_data_at(int n, short* data, int datalen) { + return datalen > n ? data[n] : 0; + } + + static jint jint_data_at(int n, short* data, int datalen) { + return datalen > n+1 ? jint_from_data(&data[n]) : short_data_at(n, data, datalen); + } + + // Update methods for relocation information + // (since code is dynamically patched, we also need to dynamically update the relocation info) + // Both methods takes old_type, so it is able to performe sanity checks on the information removed. + static void change_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type, relocType new_type); + static void remove_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type); + + // Machine dependent stuff + #include "incls/_relocInfo_pd.hpp.incl" + + protected: + // Derived constant, based on format_width which is PD: + enum { + offset_width = nontype_width - format_width, + offset_mask = (1<<offset_width) - 1, + format_mask = (1<<format_width) - 1 + }; + public: + enum { + // Conservatively large estimate of maximum length (in shorts) + // of any relocation record (probably breakpoints are largest). + // Extended format is length prefix, data words, and tag/offset suffix. + length_limit = 1 + 1 + (3*BytesPerWord/BytesPerShort) + 1, + have_format = format_width > 0 + }; +}; + +#define FORWARD_DECLARE_EACH_CLASS(name) \ +class name##_Relocation; +APPLY_TO_RELOCATIONS(FORWARD_DECLARE_EACH_CLASS) +#undef FORWARD_DECLARE_EACH_CLASS + + + +inline relocInfo filler_relocInfo() { + return relocInfo(relocInfo::none, relocInfo::offset_limit() - relocInfo::offset_unit); +} + +inline relocInfo prefix_relocInfo(int datalen) { + assert(relocInfo::fits_into_immediate(datalen), "datalen in limits"); + return relocInfo(relocInfo::data_prefix_tag, relocInfo::RAW_BITS, relocInfo::datalen_tag | datalen); +} + + +// Holder for flyweight relocation objects. +// Although the flyweight subclasses are of varying sizes, +// the holder is "one size fits all". +class RelocationHolder VALUE_OBJ_CLASS_SPEC { + friend class Relocation; + friend class CodeSection; + + private: + // this preallocated memory must accommodate all subclasses of Relocation + // (this number is assertion-checked in Relocation::operator new) + enum { _relocbuf_size = 5 }; + void* _relocbuf[ _relocbuf_size ]; + + public: + Relocation* reloc() const { return (Relocation*) &_relocbuf[0]; } + inline relocInfo::relocType type() const; + + // Add a constant offset to a relocation. Helper for class Address. + RelocationHolder plus(int offset) const; + + inline RelocationHolder(); // initializes type to none + + inline RelocationHolder(Relocation* r); // make a copy + + static const RelocationHolder none; +}; + +// A RelocIterator iterates through the relocation information of a CodeBlob. +// It is a variable BoundRelocation which is able to take on successive +// values as it is advanced through a code stream. +// Usage: +// RelocIterator iter(nm); +// while (iter.next()) { +// iter.reloc()->some_operation(); +// } +// or: +// RelocIterator iter(nm); +// while (iter.next()) { +// switch (iter.type()) { +// case relocInfo::oop_type : +// case relocInfo::ic_type : +// case relocInfo::prim_type : +// case relocInfo::uncommon_type : +// case relocInfo::runtime_call_type : +// case relocInfo::internal_word_type: +// case relocInfo::external_word_type: +// ... +// } +// } + +class RelocIterator : public StackObj { + enum { SECT_CONSTS = 2, + SECT_LIMIT = 3 }; // must be equal to CodeBuffer::SECT_LIMIT + friend class Relocation; + friend class relocInfo; // for change_reloc_info_for_address only + typedef relocInfo::relocType relocType; + + private: + address _limit; // stop producing relocations after this _addr + relocInfo* _current; // the current relocation information + relocInfo* _end; // end marker; we're done iterating when _current == _end + CodeBlob* _code; // compiled method containing _addr + address _addr; // instruction to which the relocation applies + short _databuf; // spare buffer for compressed data + short* _data; // pointer to the relocation's data + short _datalen; // number of halfwords in _data + char _format; // position within the instruction + + // Base addresses needed to compute targets of section_word_type relocs. + address _section_start[SECT_LIMIT]; + + void set_has_current(bool b) { + _datalen = !b ? -1 : 0; + debug_only(_data = NULL); + } + void set_current(relocInfo& ri) { + _current = &ri; + set_has_current(true); + } + + RelocationHolder _rh; // where the current relocation is allocated + + relocInfo* current() const { assert(has_current(), "must have current"); + return _current; } + + void set_limits(address begin, address limit); + + void advance_over_prefix(); // helper method + + void initialize_misc() { + set_has_current(false); + for (int i = 0; i < SECT_LIMIT; i++) { + _section_start[i] = NULL; // these will be lazily computed, if needed + } + } + + address compute_section_start(int n) const; // out-of-line helper + + void initialize(CodeBlob* nm, address begin, address limit); + + friend class PatchingRelocIterator; + // make an uninitialized one, for PatchingRelocIterator: + RelocIterator() { initialize_misc(); } + + public: + // constructor + RelocIterator(CodeBlob* cb, address begin = NULL, address limit = NULL); + RelocIterator(CodeSection* cb, address begin = NULL, address limit = NULL); + + // get next reloc info, return !eos + bool next() { + _current++; + assert(_current <= _end, "must not overrun relocInfo"); + if (_current == _end) { + set_has_current(false); + return false; + } + set_has_current(true); + + if (_current->is_prefix()) { + advance_over_prefix(); + assert(!current()->is_prefix(), "only one prefix at a time"); + } + + _addr += _current->addr_offset(); + + if (_limit != NULL && _addr >= _limit) { + set_has_current(false); + return false; + } + + if (relocInfo::have_format) _format = current()->format(); + return true; + } + + // accessors + address limit() const { return _limit; } + void set_limit(address x); + relocType type() const { return current()->type(); } + int format() const { return (relocInfo::have_format) ? current()->format() : 0; } + address addr() const { return _addr; } + CodeBlob* code() const { return _code; } + short* data() const { return _data; } + int datalen() const { return _datalen; } + bool has_current() const { return _datalen >= 0; } + + void set_addr(address addr) { _addr = addr; } + bool addr_in_const() const { return addr() >= section_start(SECT_CONSTS); } + + address section_start(int n) const { + address res = _section_start[n]; + return (res != NULL) ? res : compute_section_start(n); + } + + // The address points to the affected displacement part of the instruction. + // For RISC, this is just the whole instruction. + // For Intel, this is an unaligned 32-bit word. + + // type-specific relocation accessors: oop_Relocation* oop_reloc(), etc. + #define EACH_TYPE(name) \ + inline name##_Relocation* name##_reloc(); + APPLY_TO_RELOCATIONS(EACH_TYPE) + #undef EACH_TYPE + // generic relocation accessor; switches on type to call the above + Relocation* reloc(); + + // CodeBlob's have relocation indexes for faster random access: + static int locs_and_index_size(int code_size, int locs_size); + // Store an index into [dest_start+dest_count..dest_end). + // At dest_start[0..dest_count] is the actual relocation information. + // Everything else up to dest_end is free space for the index. + static void create_index(relocInfo* dest_begin, int dest_count, relocInfo* dest_end); + +#ifndef PRODUCT + public: + void print(); + void print_current(); +#endif +}; + + +// A Relocation is a flyweight object allocated within a RelocationHolder. +// It represents the relocation data of relocation record. +// So, the RelocIterator unpacks relocInfos into Relocations. + +class Relocation VALUE_OBJ_CLASS_SPEC { + friend class RelocationHolder; + friend class RelocIterator; + + private: + static void guarantee_size(); + + // When a relocation has been created by a RelocIterator, + // this field is non-null. It allows the relocation to know + // its context, such as the address to which it applies. + RelocIterator* _binding; + + protected: + RelocIterator* binding() const { + assert(_binding != NULL, "must be bound"); + return _binding; + } + void set_binding(RelocIterator* b) { + assert(_binding == NULL, "must be unbound"); + _binding = b; + assert(_binding != NULL, "must now be bound"); + } + + Relocation() { + _binding = NULL; + } + + static RelocationHolder newHolder() { + return RelocationHolder(); + } + + public: + void* operator new(size_t size, const RelocationHolder& holder) { + if (size > sizeof(holder._relocbuf)) guarantee_size(); + assert((void* const *)holder.reloc() == &holder._relocbuf[0], "ptrs must agree"); + return holder.reloc(); + } + + // make a generic relocation for a given type (if possible) + static RelocationHolder spec_simple(relocInfo::relocType rtype); + + // here is the type-specific hook which writes relocation data: + virtual void pack_data_to(CodeSection* dest) { } + + // here is the type-specific hook which reads (unpacks) relocation data: + virtual void unpack_data() { + assert(datalen()==0 || type()==relocInfo::none, "no data here"); + } + + protected: + // Helper functions for pack_data_to() and unpack_data(). + + // Most of the compression logic is confined here. + // (The "immediate data" mechanism of relocInfo works independently + // of this stuff, and acts to further compress most 1-word data prefixes.) + + // A variable-width int is encoded as a short if it will fit in 16 bits. + // The decoder looks at datalen to decide whether to unpack short or jint. + // Most relocation records are quite simple, containing at most two ints. + + static bool is_short(jint x) { return x == (short)x; } + static short* add_short(short* p, int x) { *p++ = x; return p; } + static short* add_jint (short* p, jint x) { + *p++ = relocInfo::data0_from_int(x); *p++ = relocInfo::data1_from_int(x); + return p; + } + static short* add_var_int(short* p, jint x) { // add a variable-width int + if (is_short(x)) p = add_short(p, x); + else p = add_jint (p, x); + return p; + } + + static short* pack_1_int_to(short* p, jint x0) { + // Format is one of: [] [x] [Xx] + if (x0 != 0) p = add_var_int(p, x0); + return p; + } + int unpack_1_int() { + assert(datalen() <= 2, "too much data"); + return relocInfo::jint_data_at(0, data(), datalen()); + } + + // With two ints, the short form is used only if both ints are short. + short* pack_2_ints_to(short* p, jint x0, jint x1) { + // Format is one of: [] [x y?] [Xx Y?y] + if (x0 == 0 && x1 == 0) { + // no halfwords needed to store zeroes + } else if (is_short(x0) && is_short(x1)) { + // 1-2 halfwords needed to store shorts + p = add_short(p, x0); if (x1!=0) p = add_short(p, x1); + } else { + // 3-4 halfwords needed to store jints + p = add_jint(p, x0); p = add_var_int(p, x1); + } + return p; + } + void unpack_2_ints(jint& x0, jint& x1) { + int dlen = datalen(); + short* dp = data(); + if (dlen <= 2) { + x0 = relocInfo::short_data_at(0, dp, dlen); + x1 = relocInfo::short_data_at(1, dp, dlen); + } else { + assert(dlen <= 4, "too much data"); + x0 = relocInfo::jint_data_at(0, dp, dlen); + x1 = relocInfo::jint_data_at(2, dp, dlen); + } + } + + protected: + // platform-dependent utilities for decoding and patching instructions + void pd_set_data_value (address x, intptr_t off); // a set or mem-ref + address pd_call_destination (address orig_addr = NULL); + void pd_set_call_destination (address x); + void pd_swap_in_breakpoint (address x, short* instrs, int instrlen); + void pd_swap_out_breakpoint (address x, short* instrs, int instrlen); + static int pd_breakpoint_size (); + + // this extracts the address of an address in the code stream instead of the reloc data + address* pd_address_in_code (); + + // this extracts an address from the code stream instead of the reloc data + address pd_get_address_from_code (); + + // these convert from byte offsets, to scaled offsets, to addresses + static jint scaled_offset(address x, address base) { + int byte_offset = x - base; + int offset = -byte_offset / relocInfo::addr_unit(); + assert(address_from_scaled_offset(offset, base) == x, "just checkin'"); + return offset; + } + static jint scaled_offset_null_special(address x, address base) { + // Some relocations treat offset=0 as meaning NULL. + // Handle this extra convention carefully. + if (x == NULL) return 0; + assert(x != base, "offset must not be zero"); + return scaled_offset(x, base); + } + static address address_from_scaled_offset(jint offset, address base) { + int byte_offset = -( offset * relocInfo::addr_unit() ); + return base + byte_offset; + } + + // these convert between indexes and addresses in the runtime system + static int32_t runtime_address_to_index(address runtime_address); + static address index_to_runtime_address(int32_t index); + + // helpers for mapping between old and new addresses after a move or resize + address old_addr_for(address newa, const CodeBuffer* src, CodeBuffer* dest); + address new_addr_for(address olda, const CodeBuffer* src, CodeBuffer* dest); + void normalize_address(address& addr, const CodeSection* dest, bool allow_other_sections = false); + + public: + // accessors which only make sense for a bound Relocation + address addr() const { return binding()->addr(); } + CodeBlob* code() const { return binding()->code(); } + bool addr_in_const() const { return binding()->addr_in_const(); } + protected: + short* data() const { return binding()->data(); } + int datalen() const { return binding()->datalen(); } + int format() const { return binding()->format(); } + + public: + virtual relocInfo::relocType type() { return relocInfo::none; } + + // is it a call instruction? + virtual bool is_call() { return false; } + + // is it a data movement instruction? + virtual bool is_data() { return false; } + + // some relocations can compute their own values + virtual address value(); + + // all relocations are able to reassert their values + virtual void set_value(address x); + + virtual void clear_inline_cache() { } + + // This method assumes that all virtual/static (inline) caches are cleared (since for static_call_type and + // ic_call_type is not always posisition dependent (depending on the state of the cache)). However, this is + // probably a reasonable assumption, since empty caches simplifies code reloacation. + virtual void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { } + + void print(); +}; + + +// certain inlines must be deferred until class Relocation is defined: + +inline RelocationHolder::RelocationHolder() { + // initialize the vtbl, just to keep things type-safe + new(*this) Relocation(); +} + + +inline RelocationHolder::RelocationHolder(Relocation* r) { + // wordwise copy from r (ok if it copies garbage after r) + for (int i = 0; i < _relocbuf_size; i++) { + _relocbuf[i] = ((void**)r)[i]; + } +} + + +relocInfo::relocType RelocationHolder::type() const { + return reloc()->type(); +} + +// A DataRelocation always points at a memory or load-constant instruction.. +// It is absolute on most machines, and the constant is split on RISCs. +// The specific subtypes are oop, external_word, and internal_word. +// By convention, the "value" does not include a separately reckoned "offset". +class DataRelocation : public Relocation { + public: + bool is_data() { return true; } + + // both target and offset must be computed somehow from relocation data + virtual int offset() { return 0; } + address value() = 0; + void set_value(address x) { set_value(x, offset()); } + void set_value(address x, intptr_t o) { + if (addr_in_const()) + *(address*)addr() = x; + else + pd_set_data_value(x, o); + } + + // The "o" (displacement) argument is relevant only to split relocations + // on RISC machines. In some CPUs (SPARC), the set-hi and set-lo ins'ns + // can encode more than 32 bits between them. This allows compilers to + // share set-hi instructions between addresses that differ by a small + // offset (e.g., different static variables in the same class). + // On such machines, the "x" argument to set_value on all set-lo + // instructions must be the same as the "x" argument for the + // corresponding set-hi instructions. The "o" arguments for the + // set-hi instructions are ignored, and must not affect the high-half + // immediate constant. The "o" arguments for the set-lo instructions are + // added into the low-half immediate constant, and must not overflow it. +}; + +// A CallRelocation always points at a call instruction. +// It is PC-relative on most machines. +class CallRelocation : public Relocation { + public: + bool is_call() { return true; } + + address destination() { return pd_call_destination(); } + void set_destination(address x); // pd_set_call_destination + + void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); + address value() { return destination(); } + void set_value(address x) { set_destination(x); } +}; + +class oop_Relocation : public DataRelocation { + relocInfo::relocType type() { return relocInfo::oop_type; } + + public: + // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll] + // an oop in the CodeBlob's oop pool + static RelocationHolder spec(int oop_index, int offset = 0) { + assert(oop_index > 0, "must be a pool-resident oop"); + RelocationHolder rh = newHolder(); + new(rh) oop_Relocation(oop_index, offset); + return rh; + } + // an oop in the instruction stream + static RelocationHolder spec_for_immediate() { + const int oop_index = 0; + const int offset = 0; // if you want an offset, use the oop pool + RelocationHolder rh = newHolder(); + new(rh) oop_Relocation(oop_index, offset); + return rh; + } + + private: + jint _oop_index; // if > 0, index into CodeBlob::oop_at + jint _offset; // byte offset to apply to the oop itself + + oop_Relocation(int oop_index, int offset) { + _oop_index = oop_index; _offset = offset; + } + + friend class RelocIterator; + oop_Relocation() { } + + public: + int oop_index() { return _oop_index; } + int offset() { return _offset; } + + // data is packed in "2_ints" format: [i o] or [Ii Oo] + void pack_data_to(CodeSection* dest); + void unpack_data(); + + void fix_oop_relocation(); // reasserts oop value + + address value() { return (address) *oop_addr(); } + + bool oop_is_immediate() { return oop_index() == 0; } + + oop* oop_addr(); // addr or &pool[jint_data] + oop oop_value(); // *oop_addr + // Note: oop_value transparently converts Universe::non_oop_word to NULL. +}; + +class virtual_call_Relocation : public CallRelocation { + relocInfo::relocType type() { return relocInfo::virtual_call_type; } + + public: + // "first_oop" points to the first associated set-oop. + // The oop_limit helps find the last associated set-oop. + // (See comments at the top of this file.) + static RelocationHolder spec(address first_oop, address oop_limit = NULL) { + RelocationHolder rh = newHolder(); + new(rh) virtual_call_Relocation(first_oop, oop_limit); + return rh; + } + + virtual_call_Relocation(address first_oop, address oop_limit) { + _first_oop = first_oop; _oop_limit = oop_limit; + assert(first_oop != NULL, "first oop address must be specified"); + } + + private: + address _first_oop; // location of first set-oop instruction + address _oop_limit; // search limit for set-oop instructions + + friend class RelocIterator; + virtual_call_Relocation() { } + + + public: + address first_oop(); + address oop_limit(); + + // data is packed as scaled offsets in "2_ints" format: [f l] or [Ff Ll] + // oop_limit is set to 0 if the limit falls somewhere within the call. + // When unpacking, a zero oop_limit is taken to refer to the end of the call. + // (This has the effect of bringing in the call's delay slot on SPARC.) + void pack_data_to(CodeSection* dest); + void unpack_data(); + + void clear_inline_cache(); + + // Figure out where an ic_call is hiding, given a set-oop or call. + // Either ic_call or first_oop must be non-null; the other is deduced. + // Code if non-NULL must be the CodeBlob, else it is deduced. + // The address of the patchable oop is also deduced. + // The returned iterator will enumerate over the oops and the ic_call, + // as well as any other relocations that happen to be in that span of code. + // Recognize relevant set_oops with: oop_reloc()->oop_addr() == oop_addr. + static RelocIterator parse_ic(CodeBlob* &code, address &ic_call, address &first_oop, oop* &oop_addr, bool *is_optimized); +}; + + +class opt_virtual_call_Relocation : public CallRelocation { + relocInfo::relocType type() { return relocInfo::opt_virtual_call_type; } + + public: + static RelocationHolder spec() { + RelocationHolder rh = newHolder(); + new(rh) opt_virtual_call_Relocation(); + return rh; + } + + private: + friend class RelocIterator; + opt_virtual_call_Relocation() { } + + public: + void clear_inline_cache(); + + // find the matching static_stub + address static_stub(); +}; + + +class static_call_Relocation : public CallRelocation { + relocInfo::relocType type() { return relocInfo::static_call_type; } + + public: + static RelocationHolder spec() { + RelocationHolder rh = newHolder(); + new(rh) static_call_Relocation(); + return rh; + } + + private: + friend class RelocIterator; + static_call_Relocation() { } + + public: + void clear_inline_cache(); + + // find the matching static_stub + address static_stub(); +}; + +class static_stub_Relocation : public Relocation { + relocInfo::relocType type() { return relocInfo::static_stub_type; } + + public: + static RelocationHolder spec(address static_call) { + RelocationHolder rh = newHolder(); + new(rh) static_stub_Relocation(static_call); + return rh; + } + + private: + address _static_call; // location of corresponding static_call + + static_stub_Relocation(address static_call) { + _static_call = static_call; + } + + friend class RelocIterator; + static_stub_Relocation() { } + + public: + void clear_inline_cache(); + + address static_call() { return _static_call; } + + // data is packed as a scaled offset in "1_int" format: [c] or [Cc] + void pack_data_to(CodeSection* dest); + void unpack_data(); +}; + +class runtime_call_Relocation : public CallRelocation { + relocInfo::relocType type() { return relocInfo::runtime_call_type; } + + public: + static RelocationHolder spec() { + RelocationHolder rh = newHolder(); + new(rh) runtime_call_Relocation(); + return rh; + } + + private: + friend class RelocIterator; + runtime_call_Relocation() { } + + public: +}; + +class external_word_Relocation : public DataRelocation { + relocInfo::relocType type() { return relocInfo::external_word_type; } + + public: + static RelocationHolder spec(address target) { + assert(target != NULL, "must not be null"); + RelocationHolder rh = newHolder(); + new(rh) external_word_Relocation(target); + return rh; + } + + // Use this one where all 32/64 bits of the target live in the code stream. + // The target must be an intptr_t, and must be absolute (not relative). + static RelocationHolder spec_for_immediate() { + RelocationHolder rh = newHolder(); + new(rh) external_word_Relocation(NULL); + return rh; + } + + private: + address _target; // address in runtime + + external_word_Relocation(address target) { + _target = target; + } + + friend class RelocIterator; + external_word_Relocation() { } + + public: + // data is packed as a well-known address in "1_int" format: [a] or [Aa] + // The function runtime_address_to_index is used to turn full addresses + // to short indexes, if they are pre-registered by the stub mechanism. + // If the "a" value is 0 (i.e., _target is NULL), the address is stored + // in the code stream. See external_word_Relocation::target(). + void pack_data_to(CodeSection* dest); + void unpack_data(); + + void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); + address target(); // if _target==NULL, fetch addr from code stream + address value() { return target(); } +}; + +class internal_word_Relocation : public DataRelocation { + relocInfo::relocType type() { return relocInfo::internal_word_type; } + + public: + static RelocationHolder spec(address target) { + assert(target != NULL, "must not be null"); + RelocationHolder rh = newHolder(); + new(rh) internal_word_Relocation(target); + return rh; + } + + // use this one where all the bits of the target can fit in the code stream: + static RelocationHolder spec_for_immediate() { + RelocationHolder rh = newHolder(); + new(rh) internal_word_Relocation(NULL); + return rh; + } + + internal_word_Relocation(address target) { + _target = target; + _section = -1; // self-relative + } + + protected: + address _target; // address in CodeBlob + int _section; // section providing base address, if any + + friend class RelocIterator; + internal_word_Relocation() { } + + // bit-width of LSB field in packed offset, if section >= 0 + enum { section_width = 2 }; // must equal CodeBuffer::sect_bits + + public: + // data is packed as a scaled offset in "1_int" format: [o] or [Oo] + // If the "o" value is 0 (i.e., _target is NULL), the offset is stored + // in the code stream. See internal_word_Relocation::target(). + // If _section is not -1, it is appended to the low bits of the offset. + void pack_data_to(CodeSection* dest); + void unpack_data(); + + void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); + address target(); // if _target==NULL, fetch addr from code stream + int section() { return _section; } + address value() { return target(); } +}; + +class section_word_Relocation : public internal_word_Relocation { + relocInfo::relocType type() { return relocInfo::section_word_type; } + + public: + static RelocationHolder spec(address target, int section) { + RelocationHolder rh = newHolder(); + new(rh) section_word_Relocation(target, section); + return rh; + } + + section_word_Relocation(address target, int section) { + assert(target != NULL, "must not be null"); + assert(section >= 0, "must be a valid section"); + _target = target; + _section = section; + } + + //void pack_data_to -- inherited + void unpack_data(); + + private: + friend class RelocIterator; + section_word_Relocation() { } +}; + + +class poll_Relocation : public Relocation { + bool is_data() { return true; } + relocInfo::relocType type() { return relocInfo::poll_type; } +}; + +class poll_return_Relocation : public Relocation { + bool is_data() { return true; } + relocInfo::relocType type() { return relocInfo::poll_return_type; } +}; + + +class breakpoint_Relocation : public Relocation { + relocInfo::relocType type() { return relocInfo::breakpoint_type; } + + enum { + // attributes which affect the interpretation of the data: + removable_attr = 0x0010, // buffer [i...] allows for undoing the trap + internal_attr = 0x0020, // the target is an internal addr (local stub) + settable_attr = 0x0040, // the target is settable + + // states which can change over time: + enabled_state = 0x0100, // breakpoint must be active in running code + active_state = 0x0200, // breakpoint instruction actually in code + + kind_mask = 0x000F, // mask for extracting kind + high_bit = 0x4000 // extra bit which is always set + }; + + public: + enum { + // kinds: + initialization = 1, + safepoint = 2 + }; + + // If target is NULL, 32 bits are reserved for a later set_target(). + static RelocationHolder spec(int kind, address target = NULL, bool internal_target = false) { + RelocationHolder rh = newHolder(); + new(rh) breakpoint_Relocation(kind, target, internal_target); + return rh; + } + + private: + // We require every bits value to NOT to fit into relocInfo::datalen_width, + // because we are going to actually store state in the reloc, and so + // cannot allow it to be compressed (and hence copied by the iterator). + + short _bits; // bit-encoded kind, attrs, & state + address _target; + + breakpoint_Relocation(int kind, address target, bool internal_target); + + friend class RelocIterator; + breakpoint_Relocation() { } + + short bits() const { return _bits; } + short& live_bits() const { return data()[0]; } + short* instrs() const { return data() + datalen() - instrlen(); } + int instrlen() const { return removable() ? pd_breakpoint_size() : 0; } + + void set_bits(short x) { + assert(live_bits() == _bits, "must be the only mutator of reloc info"); + live_bits() = _bits = x; + } + + public: + address target() const; + void set_target(address x); + + int kind() const { return bits() & kind_mask; } + bool enabled() const { return (bits() & enabled_state) != 0; } + bool active() const { return (bits() & active_state) != 0; } + bool internal() const { return (bits() & internal_attr) != 0; } + bool removable() const { return (bits() & removable_attr) != 0; } + bool settable() const { return (bits() & settable_attr) != 0; } + + void set_enabled(bool b); // to activate, you must also say set_active + void set_active(bool b); // actually inserts bpt (must be enabled 1st) + + // data is packed as 16 bits, followed by the target (1 or 2 words), followed + // if necessary by empty storage for saving away original instruction bytes. + void pack_data_to(CodeSection* dest); + void unpack_data(); + + // during certain operations, breakpoints must be out of the way: + void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { + assert(!active(), "cannot perform relocation on enabled breakpoints"); + } +}; + + +// We know all the xxx_Relocation classes, so now we can define these: +#define EACH_CASE(name) \ +inline name##_Relocation* RelocIterator::name##_reloc() { \ + assert(type() == relocInfo::name##_type, "type must agree"); \ + /* The purpose of the placed "new" is to re-use the same */ \ + /* stack storage for each new iteration. */ \ + name##_Relocation* r = new(_rh) name##_Relocation(); \ + r->set_binding(this); \ + r->name##_Relocation::unpack_data(); \ + return r; \ +} +APPLY_TO_RELOCATIONS(EACH_CASE); +#undef EACH_CASE + +inline RelocIterator::RelocIterator(CodeBlob* cb, address begin, address limit) { + initialize(cb, begin, limit); +} + +// if you are going to patch code, you should use this subclass of +// RelocIterator +class PatchingRelocIterator : public RelocIterator { + private: + RelocIterator _init_state; + + void prepass(); // deactivates all breakpoints + void postpass(); // reactivates all enabled breakpoints + + // do not copy these puppies; it would have unpredictable side effects + // these are private and have no bodies defined because they should not be called + PatchingRelocIterator(const RelocIterator&); + void operator=(const RelocIterator&); + + public: + PatchingRelocIterator(CodeBlob* cb, address begin =NULL, address limit =NULL) + : RelocIterator(cb, begin, limit) { prepass(); } + + ~PatchingRelocIterator() { postpass(); } +};