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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "mir_field_info.h"
     18 
     19 #include <string.h>
     20 
     21 #include "base/logging.h"
     22 #include "driver/compiler_driver.h"
     23 #include "driver/compiler_driver-inl.h"
     24 #include "mirror/class_loader.h"  // Only to allow casts in Handle<ClassLoader>.
     25 #include "mirror/dex_cache.h"     // Only to allow casts in Handle<DexCache>.
     26 #include "scoped_thread_state_change.h"
     27 #include "handle_scope-inl.h"
     28 
     29 namespace art {
     30 
     31 void MirIFieldLoweringInfo::Resolve(CompilerDriver* compiler_driver,
     32                                     const DexCompilationUnit* mUnit,
     33                                     MirIFieldLoweringInfo* field_infos, size_t count) {
     34   if (kIsDebugBuild) {
     35     DCHECK(field_infos != nullptr);
     36     DCHECK_NE(count, 0u);
     37     for (auto it = field_infos, end = field_infos + count; it != end; ++it) {
     38       MirIFieldLoweringInfo unresolved(it->field_idx_);
     39       DCHECK_EQ(memcmp(&unresolved, &*it, sizeof(*it)), 0);
     40     }
     41   }
     42 
     43   // We're going to resolve fields and check access in a tight loop. It's better to hold
     44   // the lock and needed references once than re-acquiring them again and again.
     45   ScopedObjectAccess soa(Thread::Current());
     46   StackHandleScope<3> hs(soa.Self());
     47   Handle<mirror::DexCache> dex_cache(hs.NewHandle(compiler_driver->GetDexCache(mUnit)));
     48   Handle<mirror::ClassLoader> class_loader(
     49       hs.NewHandle(compiler_driver->GetClassLoader(soa, mUnit)));
     50   Handle<mirror::Class> referrer_class(hs.NewHandle(
     51       compiler_driver->ResolveCompilingMethodsClass(soa, dex_cache, class_loader, mUnit)));
     52   // Even if the referrer class is unresolved (i.e. we're compiling a method without class
     53   // definition) we still want to resolve fields and record all available info.
     54 
     55   for (auto it = field_infos, end = field_infos + count; it != end; ++it) {
     56     uint32_t field_idx = it->field_idx_;
     57     mirror::ArtField* resolved_field =
     58         compiler_driver->ResolveField(soa, dex_cache, class_loader, mUnit, field_idx, false);
     59     if (UNLIKELY(resolved_field == nullptr)) {
     60       continue;
     61     }
     62     compiler_driver->GetResolvedFieldDexFileLocation(resolved_field,
     63         &it->declaring_dex_file_, &it->declaring_class_idx_, &it->declaring_field_idx_);
     64     bool is_volatile = compiler_driver->IsFieldVolatile(resolved_field);
     65     it->field_offset_ = resolved_field->GetOffset();
     66     std::pair<bool, bool> fast_path = compiler_driver->IsFastInstanceField(
     67         dex_cache.Get(), referrer_class.Get(), resolved_field, field_idx);
     68     it->flags_ = 0u |  // Without kFlagIsStatic.
     69         (is_volatile ? kFlagIsVolatile : 0u) |
     70         (fast_path.first ? kFlagFastGet : 0u) |
     71         (fast_path.second ? kFlagFastPut : 0u);
     72   }
     73 }
     74 
     75 void MirSFieldLoweringInfo::Resolve(CompilerDriver* compiler_driver,
     76                                     const DexCompilationUnit* mUnit,
     77                                     MirSFieldLoweringInfo* field_infos, size_t count) {
     78   if (kIsDebugBuild) {
     79     DCHECK(field_infos != nullptr);
     80     DCHECK_NE(count, 0u);
     81     for (auto it = field_infos, end = field_infos + count; it != end; ++it) {
     82       MirSFieldLoweringInfo unresolved(it->field_idx_);
     83       // In 64-bit builds, there's padding after storage_index_, don't include it in memcmp.
     84       size_t size = OFFSETOF_MEMBER(MirSFieldLoweringInfo, storage_index_) +
     85           sizeof(it->storage_index_);
     86       DCHECK_EQ(memcmp(&unresolved, &*it, size), 0);
     87     }
     88   }
     89 
     90   // We're going to resolve fields and check access in a tight loop. It's better to hold
     91   // the lock and needed references once than re-acquiring them again and again.
     92   ScopedObjectAccess soa(Thread::Current());
     93   StackHandleScope<3> hs(soa.Self());
     94   Handle<mirror::DexCache> dex_cache(hs.NewHandle(compiler_driver->GetDexCache(mUnit)));
     95   Handle<mirror::ClassLoader> class_loader(
     96       hs.NewHandle(compiler_driver->GetClassLoader(soa, mUnit)));
     97   Handle<mirror::Class> referrer_class(hs.NewHandle(
     98       compiler_driver->ResolveCompilingMethodsClass(soa, dex_cache, class_loader, mUnit)));
     99   // Even if the referrer class is unresolved (i.e. we're compiling a method without class
    100   // definition) we still want to resolve fields and record all available info.
    101 
    102   for (auto it = field_infos, end = field_infos + count; it != end; ++it) {
    103     uint32_t field_idx = it->field_idx_;
    104     mirror::ArtField* resolved_field =
    105         compiler_driver->ResolveField(soa, dex_cache, class_loader, mUnit, field_idx, true);
    106     if (UNLIKELY(resolved_field == nullptr)) {
    107       continue;
    108     }
    109     compiler_driver->GetResolvedFieldDexFileLocation(resolved_field,
    110         &it->declaring_dex_file_, &it->declaring_class_idx_, &it->declaring_field_idx_);
    111     bool is_volatile = compiler_driver->IsFieldVolatile(resolved_field) ? 1u : 0u;
    112 
    113     bool is_referrers_class, is_initialized;
    114     std::pair<bool, bool> fast_path = compiler_driver->IsFastStaticField(
    115         dex_cache.Get(), referrer_class.Get(), resolved_field, field_idx, &it->field_offset_,
    116         &it->storage_index_, &is_referrers_class, &is_initialized);
    117     it->flags_ = kFlagIsStatic |
    118         (is_volatile ? kFlagIsVolatile : 0u) |
    119         (fast_path.first ? kFlagFastGet : 0u) |
    120         (fast_path.second ? kFlagFastPut : 0u) |
    121         (is_referrers_class ? kFlagIsReferrersClass : 0u) |
    122         (is_initialized ? kFlagIsInitialized : 0u);
    123   }
    124 }
    125 
    126 }  // namespace art
    127