image_writer.cc revision e24fa61603a60ade3797e4a0c8b3fccb346cb048 
1// Copyright 2011 Google Inc. All Rights Reserved.
2
3#include "image_writer.h"
4
5#include <sys/mman.h>
6
7#include <vector>
8
9#include "UniquePtr.h"
10#include "class_linker.h"
11#include "class_loader.h"
12#include "dex_cache.h"
13#include "file.h"
14#include "globals.h"
15#include "heap.h"
16#include "image.h"
17#include "intern_table.h"
18#include "logging.h"
19#include "object.h"
20#include "runtime.h"
21#include "space.h"
22#include "utils.h"
23
24namespace art {
25
26bool ImageWriter::Write(const char* image_filename, uintptr_t image_base,
27                        const std::string& oat_filename, const std::string& strip_location_prefix) {
28  CHECK_NE(image_base, 0U);
29  image_base_ = reinterpret_cast<byte*>(image_base);
30
31  const std::vector<Space*>& spaces = Heap::GetSpaces();
32  // currently just write the last space, assuming it is the space that was being used for allocation
33  CHECK_GE(spaces.size(), 1U);
34  source_space_ = spaces[spaces.size()-1];
35
36  oat_file_.reset(OatFile::Open(oat_filename, strip_location_prefix, NULL));
37  if (oat_file_.get() == NULL) {
38    LOG(ERROR) << "Failed to open oat file " << oat_filename;
39    return false;
40  }
41
42  if (!Init()) {
43    return false;
44  }
45  Heap::CollectGarbage();
46  CalculateNewObjectOffsets();
47  CopyAndFixupObjects();
48
49  UniquePtr<File> file(OS::OpenFile(image_filename, true));
50  if (file.get() == NULL) {
51    LOG(ERROR) << "Failed to open image file " << image_filename;
52    return false;
53  }
54  bool success = file->WriteFully(image_->GetAddress(), image_top_);
55  if (!success) {
56    PLOG(ERROR) << "Failed to write image file " << image_filename;
57    return false;
58  }
59  return true;
60}
61
62bool ImageWriter::Init() {
63  size_t size = source_space_->Size();
64  int prot = PROT_READ | PROT_WRITE;
65  size_t length = RoundUp(size, kPageSize);
66  image_.reset(MemMap::Map(length, prot));
67  if (image_.get() == NULL) {
68    LOG(ERROR) << "Failed to allocate memory for image file generation";
69    return false;
70  }
71  return true;
72}
73
74void ImageWriter::CalculateNewObjectOffsetsCallback(Object* obj, void* arg) {
75  DCHECK(obj != NULL);
76  DCHECK(arg != NULL);
77  ImageWriter* image_writer = reinterpret_cast<ImageWriter*>(arg);
78  if (!image_writer->InSourceSpace(obj)) {
79    return;
80  }
81
82  // if it is a string, we want to intern it if its not interned.
83  if (obj->IsString()) {
84    // we must be an interned string that was forward referenced and already assigned
85    if (IsImageOffsetAssigned(obj)) {
86      DCHECK_EQ(obj, obj->AsString()->Intern());
87      return;
88    }
89    String* interned = obj->AsString()->Intern();
90    if (obj != interned) {
91      if (!IsImageOffsetAssigned(interned)) {
92        // interned obj is after us, allocate its location early
93        image_writer->AssignImageOffset(interned);
94      }
95      // point those looking for this object to the interned version.
96      SetImageOffset(obj, GetImageOffset(interned));
97      return;
98    }
99    // else (obj == interned), nothing to do but fall through to the normal case
100  }
101
102  image_writer->AssignImageOffset(obj);
103
104  // sniff out the DexCaches on this pass for use on the next pass
105  if (obj->IsClass()) {
106    Class* klass = obj->AsClass();
107    DexCache* dex_cache = klass->GetDexCache();
108    if (dex_cache != NULL) {
109      image_writer->dex_caches_.insert(dex_cache);
110    } else {
111      DCHECK(klass->IsArrayClass() || klass->IsPrimitive()) << PrettyClass(klass);
112    }
113  }
114}
115
116ObjectArray<Object>* ImageWriter::CreateImageRoots() const {
117  // build a Object[] of the roots needed to restore the runtime
118  Runtime* runtime = Runtime::Current();
119  ClassLinker* class_linker = runtime->GetClassLinker();
120  Class* object_array_class = class_linker->FindSystemClass("[Ljava/lang/Object;");
121  ObjectArray<Object>* image_roots = ObjectArray<Object>::Alloc(object_array_class,
122                                                                ImageHeader::kImageRootsMax);
123  image_roots->Set(ImageHeader::kJniStubArray,
124                   runtime->GetJniStubArray());
125  image_roots->Set(ImageHeader::kAbstractMethodErrorStubArray,
126                   runtime->GetAbstractMethodErrorStubArray());
127  image_roots->Set(ImageHeader::kCalleeSaveMethod,
128                   runtime->GetCalleeSaveMethod());
129  image_roots->Set(ImageHeader::kOatLocation,
130                   String::AllocFromModifiedUtf8(oat_file_->GetLocation().c_str()));
131  for (int i = 0; i < ImageHeader::kImageRootsMax; i++) {
132    CHECK(image_roots->Get(i) != NULL);
133  }
134  return image_roots;
135}
136
137void ImageWriter::CalculateNewObjectOffsets() {
138  ObjectArray<Object>* image_roots = CreateImageRoots();
139
140  HeapBitmap* heap_bitmap = Heap::GetLiveBits();
141  DCHECK(heap_bitmap != NULL);
142  DCHECK_EQ(0U, image_top_);
143
144  // leave space for the header, but do not write it yet, we need to
145  // know where image_roots is going to end up
146  image_top_ += RoundUp(sizeof(ImageHeader), 8); // 64-bit-alignment
147
148  heap_bitmap->Walk(CalculateNewObjectOffsetsCallback, this);  // TODO: add Space-limited Walk
149  DCHECK_LT(image_top_, image_->GetLength());
150
151  // Note that image_top_ is left at end of used space
152  oat_base_ = image_base_ +  RoundUp(image_top_, kPageSize);
153  byte* oat_limit = oat_base_ +  oat_file_->GetSize();
154
155  // return to write header at start of image with future location of image_roots
156  ImageHeader image_header(reinterpret_cast<uint32_t>(image_base_),
157                           reinterpret_cast<uint32_t>(GetImageAddress(image_roots)),
158                           oat_file_->GetOatHeader().GetChecksum(),
159                           reinterpret_cast<uint32_t>(oat_base_),
160                           reinterpret_cast<uint32_t>(oat_limit));
161  memcpy(image_->GetAddress(), &image_header, sizeof(image_header));
162}
163
164void ImageWriter::CopyAndFixupObjects() {
165  HeapBitmap* heap_bitmap = Heap::GetLiveBits();
166  DCHECK(heap_bitmap != NULL);
167  // TODO: heap validation can't handle this fix up pass
168  Heap::DisableObjectValidation();
169  heap_bitmap->Walk(CopyAndFixupObjectsCallback, this);  // TODO: add Space-limited Walk
170  FixupDexCaches();
171}
172
173void ImageWriter::CopyAndFixupObjectsCallback(Object* object, void* arg) {
174  DCHECK(object != NULL);
175  DCHECK(arg != NULL);
176  const Object* obj = object;
177  ImageWriter* image_writer = reinterpret_cast<ImageWriter*>(arg);
178  if (!image_writer->InSourceSpace(object)) {
179    return;
180  }
181
182  // see GetLocalAddress for similar computation
183  size_t offset = image_writer->GetImageOffset(obj);
184  byte* dst = image_writer->image_->GetAddress() + offset;
185  const byte* src = reinterpret_cast<const byte*>(obj);
186  size_t n = obj->SizeOf();
187  DCHECK_LT(offset + n, image_writer->image_->GetLength());
188  memcpy(dst, src, n);
189  Object* copy = reinterpret_cast<Object*>(dst);
190  ResetImageOffset(copy);
191  image_writer->FixupObject(obj, copy);
192}
193
194void ImageWriter::FixupObject(const Object* orig, Object* copy) {
195  DCHECK(orig != NULL);
196  DCHECK(copy != NULL);
197  copy->SetClass(down_cast<Class*>(GetImageAddress(orig->GetClass())));
198  // TODO: special case init of pointers to malloc data (or removal of these pointers)
199  if (orig->IsClass()) {
200    FixupClass(orig->AsClass(), down_cast<Class*>(copy));
201  } else if (orig->IsObjectArray()) {
202    FixupObjectArray(orig->AsObjectArray<Object>(), down_cast<ObjectArray<Object>*>(copy));
203  } else if (orig->IsMethod()) {
204    FixupMethod(orig->AsMethod(), down_cast<Method*>(copy));
205  } else {
206    FixupInstanceFields(orig, copy);
207  }
208}
209
210void ImageWriter::FixupClass(const Class* orig, Class* copy) {
211  FixupInstanceFields(orig, copy);
212  FixupStaticFields(orig, copy);
213}
214
215const void* FixupCode(const ByteArray* copy_code_array, const void* orig_code) {
216  // TODO: change to DCHECK when all code compiling
217  if (copy_code_array == NULL) {
218    return NULL;
219  }
220  const void* copy_code = copy_code_array->GetData();
221  // TODO: remember InstructionSet with each code array so we know if we need to do thumb fixup?
222  if ((reinterpret_cast<uintptr_t>(orig_code) % 2) == 1) {
223    return reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(copy_code) + 1);
224  }
225  return copy_code;
226}
227
228void ImageWriter::FixupMethod(const Method* orig, Method* copy) {
229  FixupInstanceFields(orig, copy);
230
231  // OatWriter clears the code_array_ after writing the code.
232  // It replaces the code_ with an offset value we now adjust to be a pointer.
233  DCHECK(copy->code_array_ == NULL)
234          << PrettyMethod(orig)
235          << " orig_code_array_=" << orig->GetCodeArray() << " orig_code_=" << orig->GetCode()
236          << " copy_code_array_=" << copy->code_array_ << " orig_code_=" << copy->code_
237          << " jni_stub=" << Runtime::Current()->GetJniStubArray()
238          << " ame_stub=" << Runtime::Current()->GetAbstractMethodErrorStubArray();
239  copy->invoke_stub_ = reinterpret_cast<Method::InvokeStub*>(FixupCode(copy->invoke_stub_array_, reinterpret_cast<void*>(orig->invoke_stub_)));
240  if (orig->IsNative()) {
241    ByteArray* orig_jni_stub_array_ = Runtime::Current()->GetJniStubArray();
242    ByteArray* copy_jni_stub_array_ = down_cast<ByteArray*>(GetImageAddress(orig_jni_stub_array_));
243    copy->native_method_ = copy_jni_stub_array_->GetData();
244    copy->code_ = oat_base_ + orig->GetOatCodeOffset();
245  } else {
246    DCHECK(copy->native_method_ == NULL) << copy->native_method_;
247    if (orig->IsAbstract()) {
248        ByteArray* orig_ame_stub_array_ = Runtime::Current()->GetAbstractMethodErrorStubArray();
249        ByteArray* copy_ame_stub_array_ = down_cast<ByteArray*>(GetImageAddress(orig_ame_stub_array_));
250        copy->code_ = copy_ame_stub_array_->GetData();
251    } else {
252        copy->code_ = oat_base_ + orig->GetOatCodeOffset();
253    }
254  }
255}
256
257void ImageWriter::FixupObjectArray(const ObjectArray<Object>* orig, ObjectArray<Object>* copy) {
258  for (int32_t i = 0; i < orig->GetLength(); ++i) {
259    const Object* element = orig->Get(i);
260    copy->SetWithoutChecks(i, GetImageAddress(element));
261  }
262}
263
264void ImageWriter::FixupInstanceFields(const Object* orig, Object* copy) {
265  DCHECK(orig != NULL);
266  DCHECK(copy != NULL);
267  Class* klass = orig->GetClass();
268  DCHECK(klass != NULL);
269  FixupFields(orig,
270              copy,
271              klass->GetReferenceInstanceOffsets(),
272              false);
273}
274
275void ImageWriter::FixupStaticFields(const Class* orig, Class* copy) {
276  DCHECK(orig != NULL);
277  DCHECK(copy != NULL);
278  FixupFields(orig,
279              copy,
280              orig->GetReferenceStaticOffsets(),
281              true);
282}
283
284void ImageWriter::FixupFields(const Object* orig,
285                              Object* copy,
286                              uint32_t ref_offsets,
287                              bool is_static) {
288  if (ref_offsets != CLASS_WALK_SUPER) {
289    // Found a reference offset bitmap.  Fixup the specified offsets.
290    while (ref_offsets != 0) {
291      size_t right_shift = CLZ(ref_offsets);
292      MemberOffset byte_offset = CLASS_OFFSET_FROM_CLZ(right_shift);
293      const Object* ref = orig->GetFieldObject<const Object*>(byte_offset, false);
294      copy->SetFieldObject(byte_offset, GetImageAddress(ref), false);
295      ref_offsets &= ~(CLASS_HIGH_BIT >> right_shift);
296    }
297  } else {
298    // There is no reference offset bitmap.  In the non-static case,
299    // walk up the class inheritance hierarchy and find reference
300    // offsets the hard way. In the static case, just consider this
301    // class.
302    for (const Class *klass = is_static ? orig->AsClass() : orig->GetClass();
303         klass != NULL;
304         klass = is_static ? NULL : klass->GetSuperClass()) {
305      size_t num_reference_fields = (is_static
306                                     ? klass->NumReferenceStaticFields()
307                                     : klass->NumReferenceInstanceFields());
308      for (size_t i = 0; i < num_reference_fields; ++i) {
309        Field* field = (is_static
310                        ? klass->GetStaticField(i)
311                        : klass->GetInstanceField(i));
312        MemberOffset field_offset = field->GetOffset();
313        const Object* ref = orig->GetFieldObject<const Object*>(field_offset, false);
314        copy->SetFieldObject(field_offset, GetImageAddress(ref), false);
315      }
316    }
317  }
318}
319
320void ImageWriter::FixupDexCaches() {
321  typedef Set::const_iterator It;  // TODO: C++0x auto
322  for (It it = dex_caches_.begin(), end = dex_caches_.end(); it != end; ++it) {
323    DexCache* orig = *it;
324    DexCache* copy = down_cast<DexCache*>(GetLocalAddress(orig));
325    FixupDexCache(orig, copy);
326  }
327}
328
329void ImageWriter::FixupDexCache(const DexCache* orig, DexCache* copy) {
330  CHECK(orig != NULL);
331  CHECK(copy != NULL);
332
333  CodeAndDirectMethods* orig_cadms = orig->GetCodeAndDirectMethods();
334  CodeAndDirectMethods* copy_cadms = down_cast<CodeAndDirectMethods*>(GetLocalAddress(orig_cadms));
335  for (size_t i = 0; i < orig->NumResolvedMethods(); i++) {
336    Method* orig_method = orig->GetResolvedMethod(i);
337    // if it was resolved in the original, resolve it in the copy
338    if (orig_method != NULL
339        && InSourceSpace(orig_method)
340        && orig_method == orig_cadms->GetResolvedMethod(i)) {
341      Method* copy_method = down_cast<Method*>(GetLocalAddress(orig_method));
342      copy_cadms->Set(CodeAndDirectMethods::CodeIndex(i),
343                      reinterpret_cast<int32_t>(copy_method->code_));
344      copy_cadms->Set(CodeAndDirectMethods::MethodIndex(i),
345                      reinterpret_cast<int32_t>(GetImageAddress(orig_method)));
346    }
347  }
348}
349
350}  // namespace art
351