jdk8-mips64-public/hotspot: comparison src/share/vm/code/relocInfo.hpp

--1:000000000000
+:f90c822e73f8
+/*
+* Copyright (c) 1997, 2013, 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"
+class NativeMovConstReg;
+// 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.
+//    metadata_Relocation, ... (subclasses of Relocation)
+//      The location of some type-specific operations (metadata_addr, ...).
+//      Also, the source of relocation specs (metadata_Relocation::spec, ...).
+//    oop_Relocation, ... (subclasses of Relocation)
+//      oops in the code stream (strings, class loaders)
+//      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.
+//    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, relocInfo::metadata_type -- a reference to an oop or meta data
+//   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::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
+metadata_type           = 12, // metadata that used to be oops
+trampoline_stub_type    = 13, // stub-entry for trampoline
+yet_unused_type_1       = 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(metadata) \
+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(section_word) \
+visitor(trampoline_stub) \
+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);
+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.
+// 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 = 0) {
+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);
+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) throw() {
+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);
+// 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.
+};
+// copy of oop_Relocation for now but may delete stuff in both/either
+class metadata_Relocation : public DataRelocation {
+relocInfo::relocType type() { return relocInfo::metadata_type; }
+public:
+// encode in one of these formats:  [] [n] [n l] [Nn l] [Nn Ll]
+// an metadata in the CodeBlob's metadata pool
+static RelocationHolder spec(int metadata_index, int offset = 0) {
+assert(metadata_index > 0, "must be a pool-resident metadata");
+RelocationHolder rh = newHolder();
+new(rh) metadata_Relocation(metadata_index, offset);
+return rh;
+}
+// an metadata in the instruction stream
+static RelocationHolder spec_for_immediate() {
+const int metadata_index = 0;
+const int offset    = 0;    // if you want an offset, use the metadata pool
+RelocationHolder rh = newHolder();
+new(rh) metadata_Relocation(metadata_index, offset);
+return rh;
+}
+private:
+jint _metadata_index;            // if > 0, index into nmethod::metadata_at
+jint _offset;                     // byte offset to apply to the metadata itself
+metadata_Relocation(int metadata_index, int offset) {
+_metadata_index = metadata_index; _offset = offset;
+}
+friend class RelocIterator;
+metadata_Relocation() { }
+// Fixes a Metadata pointer in the code. Most platforms embeds the
+// Metadata pointer in the code at compile time so this is empty
+// for them.
+void pd_fix_value(address x);
+public:
+int metadata_index() { return _metadata_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_metadata_relocation();        // reasserts metadata value
+void verify_metadata_relocation();
+address value()  { return (address) *metadata_addr(); }
+bool metadata_is_immediate()  { return metadata_index() == 0; }
+Metadata**   metadata_addr();                  // addr or &pool[jint_data]
+Metadata*    metadata_value();                 // *metadata_addr
+// Note:  metadata_value transparently converts Universe::non_metadata_word to NULL.
+};
+class virtual_call_Relocation : public CallRelocation {
+relocInfo::relocType type() { return relocInfo::virtual_call_type; }
+public:
+// "cached_value" 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 cached_value) {
+RelocationHolder rh = newHolder();
+new(rh) virtual_call_Relocation(cached_value);
+return rh;
+}
+virtual_call_Relocation(address cached_value) {
+_cached_value = cached_value;
+assert(cached_value != NULL, "first oop address must be specified");
+}
+private:
+address _cached_value;               // location of set-value instruction
+friend class RelocIterator;
+virtual_call_Relocation() { }
+public:
+address cached_value();
+// 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();
+};
+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:
+};
+// Trampoline Relocations.
+// A trampoline allows to encode a small branch in the code, even if there
+// is the chance that this branch can not reach all possible code locations.
+// If the relocation finds that a branch is too far for the instruction
+// in the code, it can patch it to jump to the trampoline where is
+// sufficient space for a far branch. Needed on PPC.
+class trampoline_stub_Relocation : public Relocation {
+relocInfo::relocType type() { return relocInfo::trampoline_stub_type; }
+public:
+static RelocationHolder spec(address static_call) {
+RelocationHolder rh = newHolder();
+return (new (rh) trampoline_stub_Relocation(static_call));
+}
+private:
+address _owner;    // Address of the NativeCall that owns the trampoline.
+trampoline_stub_Relocation(address owner) {
+_owner = owner;
+}
+friend class RelocIterator;
+trampoline_stub_Relocation() { }
+public:
+// Return the address of the NativeCall that owns the trampoline.
+address owner() { return _owner; }
+void pack_data_to(CodeSection * dest);
+void unpack_data();
+// Find the trampoline stub for a call.
+static address get_trampoline_for(address call, nmethod* code);
+};
+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);
+};
+// 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);
+}
+#endif // SHARE_VM_CODE_RELOCINFO_HPP

Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/code/relocInfo.hpp

src/share/vm/code/relocInfo.hpp