Mercurial > hg > graal-compiler
view src/share/vm/code/relocInfo.hpp @ 6494:df02fa2bce58
refactored all AMD64 specific HotSpot code in com.oracle.graal.hotspot.target.amd64 package
author | Doug Simon <doug.simon@oracle.com> |
---|---|
date | Wed, 03 Oct 2012 00:25:30 +0200 |
parents | 6c97c830fb6f |
children | da91efe96a93 |
line wrap: on
line source
/* * Copyright (c) 1997, 2011, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_VM_CODE_RELOCINFO_HPP #define SHARE_VM_CODE_RELOCINFO_HPP #include "memory/allocation.hpp" #include "utilities/top.hpp" // 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 #ifdef TARGET_ARCH_x86 # include "relocInfo_x86.hpp" #endif #ifdef TARGET_ARCH_sparc # include "relocInfo_sparc.hpp" #endif #ifdef TARGET_ARCH_zero # include "relocInfo_zero.hpp" #endif #ifdef TARGET_ARCH_arm # include "relocInfo_arm.hpp" #endif #ifdef TARGET_ARCH_ppc # include "relocInfo_ppc.hpp" #endif 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_LIMIT = 3 }; // must be equal to CodeBuffer::SECT_LIMIT, checked in ctor 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 nmethod* _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]; address _section_end [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(); void initialize(nmethod* nm, address begin, address limit); friend class PatchingRelocIterator; // make an uninitialized one, for PatchingRelocIterator: RelocIterator() { initialize_misc(); } public: // constructor RelocIterator(nmethod* nm, 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; } nmethod* 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; address section_start(int n) const { assert(_section_start[n], "must be initialized"); return _section_start[n]; } address section_end(int n) const { assert(_section_end[n], "must be initialized"); return _section_end[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"); } static bool is_reloc_index(intptr_t index) { return 0 < index && index < os::vm_page_size(); } 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, bool verify_only = false); // a set or mem-ref void pd_verify_data_value (address x, intptr_t off) { pd_set_data_value(x, off, true); } 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(); } nmethod* 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); } void verify_value(address x) { if (addr_in_const()) assert(*(address*)addr() == x, "must agree"); else pd_verify_data_value(x, offset()); } // 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 void verify_oop_relocation(); 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 nmethod, 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(nmethod* &nm, 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; } // Some address looking values aren't safe to treat as relocations // and should just be treated as constants. static bool can_be_relocated(address target) { return target != NULL && !is_reloc_index((intptr_t)target); } 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; } void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); }; class poll_return_Relocation : public Relocation { bool is_data() { return true; } relocInfo::relocType type() { return relocInfo::poll_return_type; } void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); }; 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(nmethod* nm, address begin, address limit) { initialize(nm, 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(nmethod* nm, address begin = NULL, address limit = NULL) : RelocIterator(nm, begin, limit) { prepass(); } ~PatchingRelocIterator() { postpass(); } }; #endif // SHARE_VM_CODE_RELOCINFO_HPP