1 /*
  2  * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
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 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
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 24 
 25 #ifndef SHARE_CDS_ARCHIVEUTILS_HPP
 26 #define SHARE_CDS_ARCHIVEUTILS_HPP
 27 
 28 #include "logging/log.hpp"
 29 #include "memory/iterator.hpp"
 30 #include "memory/virtualspace.hpp"
 31 #include "utilities/bitMap.hpp"
 32 #include "utilities/exceptions.hpp"
 33 #include "utilities/macros.hpp"
 34 
 35 class BootstrapInfo;
 36 class ReservedSpace;
 37 class VirtualSpace;
 38 
 39 // ArchivePtrMarker is used to mark the location of pointers embedded in a CDS archive. E.g., when an
 40 // InstanceKlass k is dumped, we mark the location of the k->_name pointer by effectively calling
 41 // mark_pointer(/*ptr_loc=*/&k->_name). It's required that (_prt_base <= ptr_loc < _ptr_end). _ptr_base is
 42 // fixed, but _ptr_end can be expanded as more objects are dumped.
 43 class ArchivePtrMarker : AllStatic {
 44   static CHeapBitMap*  _ptrmap;
 45   static VirtualSpace* _vs;
 46 
 47   // Once _ptrmap is compacted, we don't allow bit marking anymore. This is to
 48   // avoid unintentional copy operations after the bitmap has been finalized and written.
 49   static bool         _compacted;
 50 
 51   static address* ptr_base() { return (address*)_vs->low();  } // committed lower bound (inclusive)
 52   static address* ptr_end()  { return (address*)_vs->high(); } // committed upper bound (exclusive)
 53 
 54 public:
 55   static void initialize(CHeapBitMap* ptrmap, VirtualSpace* vs);
 56   static void mark_pointer(address* ptr_loc);
 57   static void clear_pointer(address* ptr_loc);
 58   static void compact(address relocatable_base, address relocatable_end);
 59   static void compact(size_t max_non_null_offset);
 60 
 61   template <typename T>
 62   static void mark_pointer(T* ptr_loc) {
 63     mark_pointer((address*)ptr_loc);
 64   }
 65 
 66   template <typename T>
 67   static void set_and_mark_pointer(T* ptr_loc, T ptr_value) {
 68     *ptr_loc = ptr_value;
 69     mark_pointer(ptr_loc);
 70   }
 71 
 72   static CHeapBitMap* ptrmap() {
 73     return _ptrmap;
 74   }
 75 
 76   static void reset_map_and_vs() {
 77     _ptrmap = nullptr;
 78     _vs = nullptr;
 79   }
 80 };
 81 
 82 // SharedDataRelocator is used to shift pointers in the CDS archive.
 83 //
 84 // The CDS archive is basically a contiguous block of memory (divided into several regions)
 85 // that contains multiple objects. The objects may contain direct pointers that point to other objects
 86 // within the archive (e.g., InstanceKlass::_name points to a Symbol in the archive). During dumping, we
 87 // built a bitmap that marks the locations of all these pointers (using ArchivePtrMarker, see comments above).
 88 //
 89 // The contents of the archive assumes that it’s mapped at the default SharedBaseAddress (e.g. 0x800000000).
 90 // If the archive ends up being mapped at a different address (e.g. 0x810000000), SharedDataRelocator
 91 // is used to shift each marked pointer by a delta (0x10000000 in this example), so that it points to
 92 // the actually mapped location of the target object.
 93 class SharedDataRelocator: public BitMapClosure {
 94   // for all (address** p), where (is_marked(p) && _patch_base <= p && p < _patch_end) { *p += delta; }
 95 
 96   // Patch all pointers within this region that are marked.
 97   address* _patch_base;
 98   address* _patch_end;
 99 
100   // Before patching, all pointers must point to this region.
101   address _valid_old_base;
102   address _valid_old_end;
103 
104   // After patching, all pointers must point to this region.
105   address _valid_new_base;
106   address _valid_new_end;
107 
108   // How much to relocate for each pointer.
109   intx _delta;
110 
111  public:
112   SharedDataRelocator(address* patch_base, address* patch_end,
113                       address valid_old_base, address valid_old_end,
114                       address valid_new_base, address valid_new_end, intx delta) :
115     _patch_base(patch_base), _patch_end(patch_end),
116     _valid_old_base(valid_old_base), _valid_old_end(valid_old_end),
117     _valid_new_base(valid_new_base), _valid_new_end(valid_new_end),
118     _delta(delta) {
119     log_debug(cds, reloc)("SharedDataRelocator::_patch_base     = " PTR_FORMAT, p2i(_patch_base));
120     log_debug(cds, reloc)("SharedDataRelocator::_patch_end      = " PTR_FORMAT, p2i(_patch_end));
121     log_debug(cds, reloc)("SharedDataRelocator::_valid_old_base = " PTR_FORMAT, p2i(_valid_old_base));
122     log_debug(cds, reloc)("SharedDataRelocator::_valid_old_end  = " PTR_FORMAT, p2i(_valid_old_end));
123     log_debug(cds, reloc)("SharedDataRelocator::_valid_new_base = " PTR_FORMAT, p2i(_valid_new_base));
124     log_debug(cds, reloc)("SharedDataRelocator::_valid_new_end  = " PTR_FORMAT, p2i(_valid_new_end));
125   }
126 
127   bool do_bit(size_t offset);
128 };
129 
130 class DumpRegion {
131 private:
132   const char* _name;
133   char* _base;
134   char* _top;
135   char* _end;
136   uintx _max_delta;
137   bool _is_packed;
138   ReservedSpace* _rs;
139   VirtualSpace* _vs;
140 
141   void commit_to(char* newtop);
142 
143 public:
144   DumpRegion(const char* name, uintx max_delta = 0)
145     : _name(name), _base(NULL), _top(NULL), _end(NULL),
146       _max_delta(max_delta), _is_packed(false) {}
147 
148   char* expand_top_to(char* newtop);
149   char* allocate(size_t num_bytes);
150 
151   void append_intptr_t(intptr_t n, bool need_to_mark = false) NOT_CDS_RETURN;
152 
153   char* base()      const { return _base;        }
154   char* top()       const { return _top;         }
155   char* end()       const { return _end;         }
156   size_t reserved() const { return _end - _base; }
157   size_t used()     const { return _top - _base; }
158   bool is_packed()  const { return _is_packed;   }
159   bool is_allocatable() const {
160     return !is_packed() && _base != NULL;
161   }
162 
163   void print(size_t total_bytes) const;
164   void print_out_of_space_msg(const char* failing_region, size_t needed_bytes);
165 
166   void init(ReservedSpace* rs, VirtualSpace* vs);
167 
168   void pack(DumpRegion* next = NULL);
169 
170   bool contains(char* p) {
171     return base() <= p && p < top();
172   }
173 };
174 
175 // Closure for serializing initialization data out to a data area to be
176 // written to the shared file.
177 
178 class WriteClosure : public SerializeClosure {
179 private:
180   DumpRegion* _dump_region;
181 
182 public:
183   WriteClosure(DumpRegion* r) {
184     _dump_region = r;
185   }
186 
187   void do_ptr(void** p) {
188     _dump_region->append_intptr_t((intptr_t)*p, true);
189   }
190 
191   void do_u4(u4* p) {
192     _dump_region->append_intptr_t((intptr_t)(*p));
193   }
194 
195   void do_bool(bool *p) {
196     _dump_region->append_intptr_t((intptr_t)(*p));
197   }
198 
199   void do_tag(int tag) {
200     _dump_region->append_intptr_t((intptr_t)tag);
201   }
202 
203   void do_oop(oop* o);
204   void do_region(u_char* start, size_t size);
205   bool reading() const { return false; }
206 };
207 
208 // Closure for serializing initialization data in from a data area
209 // (ptr_array) read from the shared file.
210 
211 class ReadClosure : public SerializeClosure {
212 private:
213   intptr_t** _ptr_array;
214 
215   inline intptr_t nextPtr() {
216     return *(*_ptr_array)++;
217   }
218 
219 public:
220   ReadClosure(intptr_t** ptr_array) { _ptr_array = ptr_array; }
221 
222   void do_ptr(void** p);
223   void do_u4(u4* p);
224   void do_bool(bool *p);
225   void do_tag(int tag);
226   void do_oop(oop *p);
227   void do_region(u_char* start, size_t size);
228   bool reading() const { return true; }
229 };
230 
231 class ArchiveUtils {
232 public:
233   static void log_to_classlist(BootstrapInfo* bootstrap_specifier, TRAPS) NOT_CDS_RETURN;
234 };
235 
236 #endif // SHARE_CDS_ARCHIVEUTILS_HPP