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diff --git a/compiler/dex/verified_method.cc b/compiler/dex/verified_method.cc
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+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "verified_method.h"
+
+#include <algorithm>
+#include <vector>
+
+#include "base/logging.h"
+#include "base/stl_util.h"
+#include "dex_file.h"
+#include "dex_instruction.h"
+#include "dex_instruction-inl.h"
+#include "base/mutex.h"
+#include "base/mutex-inl.h"
+#include "mirror/art_method.h"
+#include "mirror/art_method-inl.h"
+#include "mirror/class.h"
+#include "mirror/class-inl.h"
+#include "mirror/dex_cache.h"
+#include "mirror/dex_cache-inl.h"
+#include "mirror/object.h"
+#include "mirror/object-inl.h"
+#include "UniquePtr.h"
+#include "verifier/dex_gc_map.h"
+#include "verifier/method_verifier.h"
+#include "verifier/method_verifier-inl.h"
+#include "verifier/register_line.h"
+#include "verifier/register_line-inl.h"
+
+namespace art {
+
+const VerifiedMethod* VerifiedMethod::Create(verifier::MethodVerifier* method_verifier,
+ bool compile) {
+ UniquePtr<VerifiedMethod> verified_method(new VerifiedMethod);
+ if (compile) {
+ /* Generate a register map. */
+ if (!verified_method->GenerateGcMap(method_verifier)) {
+ CHECK(method_verifier->HasFailures());
+ return nullptr; // Not a real failure, but a failure to encode.
+ }
+ if (kIsDebugBuild) {
+ VerifyGcMap(method_verifier, verified_method->dex_gc_map_);
+ }
+
+ // TODO: move this out when DEX-to-DEX supports devirtualization.
+ if (method_verifier->HasVirtualOrInterfaceInvokes()) {
+ verified_method->GenerateDevirtMap(method_verifier);
+ }
+ }
+
+ if (method_verifier->HasCheckCasts()) {
+ verified_method->GenerateSafeCastSet(method_verifier);
+ }
+ return verified_method.release();
+}
+
+const MethodReference* VerifiedMethod::GetDevirtTarget(uint32_t dex_pc) const {
+ auto it = devirt_map_.find(dex_pc);
+ return (it != devirt_map_.end()) ? &it->second : nullptr;
+}
+
+bool VerifiedMethod::IsSafeCast(uint32_t pc) const {
+ return std::binary_search(safe_cast_set_.begin(), safe_cast_set_.end(), pc);
+}
+
+bool VerifiedMethod::GenerateGcMap(verifier::MethodVerifier* method_verifier) {
+ DCHECK(dex_gc_map_.empty());
+ size_t num_entries, ref_bitmap_bits, pc_bits;
+ ComputeGcMapSizes(method_verifier, &num_entries, &ref_bitmap_bits, &pc_bits);
+ // There's a single byte to encode the size of each bitmap.
+ if (ref_bitmap_bits >= (8 /* bits per byte */ * 8192 /* 13-bit size */ )) {
+ // TODO: either a better GC map format or per method failures
+ method_verifier->Fail(verifier::VERIFY_ERROR_BAD_CLASS_HARD)
+ << "Cannot encode GC map for method with " << ref_bitmap_bits << " registers";
+ return false;
+ }
+ size_t ref_bitmap_bytes = (ref_bitmap_bits + 7) / 8;
+ // There are 2 bytes to encode the number of entries.
+ if (num_entries >= 65536) {
+ // TODO: Either a better GC map format or per method failures.
+ method_verifier->Fail(verifier::VERIFY_ERROR_BAD_CLASS_HARD)
+ << "Cannot encode GC map for method with " << num_entries << " entries";
+ return false;
+ }
+ size_t pc_bytes;
+ verifier::RegisterMapFormat format;
+ if (pc_bits <= 8) {
+ format = verifier::kRegMapFormatCompact8;
+ pc_bytes = 1;
+ } else if (pc_bits <= 16) {
+ format = verifier::kRegMapFormatCompact16;
+ pc_bytes = 2;
+ } else {
+ // TODO: Either a better GC map format or per method failures.
+ method_verifier->Fail(verifier::VERIFY_ERROR_BAD_CLASS_HARD)
+ << "Cannot encode GC map for method with "
+ << (1 << pc_bits) << " instructions (number is rounded up to nearest power of 2)";
+ return false;
+ }
+ size_t table_size = ((pc_bytes + ref_bitmap_bytes) * num_entries) + 4;
+ dex_gc_map_.reserve(table_size);
+ // Write table header.
+ dex_gc_map_.push_back(format | ((ref_bitmap_bytes & ~0xFF) >> 5));
+ dex_gc_map_.push_back(ref_bitmap_bytes & 0xFF);
+ dex_gc_map_.push_back(num_entries & 0xFF);
+ dex_gc_map_.push_back((num_entries >> 8) & 0xFF);
+ // Write table data.
+ const DexFile::CodeItem* code_item = method_verifier->CodeItem();
+ for (size_t i = 0; i < code_item->insns_size_in_code_units_; i++) {
+ if (method_verifier->GetInstructionFlags(i).IsCompileTimeInfoPoint()) {
+ dex_gc_map_.push_back(i & 0xFF);
+ if (pc_bytes == 2) {
+ dex_gc_map_.push_back((i >> 8) & 0xFF);
+ }
+ verifier::RegisterLine* line = method_verifier->GetRegLine(i);
+ line->WriteReferenceBitMap(dex_gc_map_, ref_bitmap_bytes);
+ }
+ }
+ DCHECK_EQ(dex_gc_map_.size(), table_size);
+ return true;
+}
+
+void VerifiedMethod::VerifyGcMap(verifier::MethodVerifier* method_verifier,
+ const std::vector<uint8_t>& data) {
+ // Check that for every GC point there is a map entry, there aren't entries for non-GC points,
+ // that the table data is well formed and all references are marked (or not) in the bitmap.
+ verifier::DexPcToReferenceMap map(&data[0]);
+ DCHECK_EQ(data.size(), map.RawSize());
+ size_t map_index = 0;
+ const DexFile::CodeItem* code_item = method_verifier->CodeItem();
+ for (size_t i = 0; i < code_item->insns_size_in_code_units_; i++) {
+ const uint8_t* reg_bitmap = map.FindBitMap(i, false);
+ if (method_verifier->GetInstructionFlags(i).IsCompileTimeInfoPoint()) {
+ DCHECK_LT(map_index, map.NumEntries());
+ DCHECK_EQ(map.GetDexPc(map_index), i);
+ DCHECK_EQ(map.GetBitMap(map_index), reg_bitmap);
+ map_index++;
+ verifier::RegisterLine* line = method_verifier->GetRegLine(i);
+ for (size_t j = 0; j < code_item->registers_size_; j++) {
+ if (line->GetRegisterType(j).IsNonZeroReferenceTypes()) {
+ DCHECK_LT(j / 8, map.RegWidth());
+ DCHECK_EQ((reg_bitmap[j / 8] >> (j % 8)) & 1, 1);
+ } else if ((j / 8) < map.RegWidth()) {
+ DCHECK_EQ((reg_bitmap[j / 8] >> (j % 8)) & 1, 0);
+ } else {
+ // If a register doesn't contain a reference then the bitmap may be shorter than the line.
+ }
+ }
+ } else {
+ DCHECK(reg_bitmap == NULL);
+ }
+ }
+}
+
+void VerifiedMethod::ComputeGcMapSizes(verifier::MethodVerifier* method_verifier,
+ size_t* gc_points, size_t* ref_bitmap_bits,
+ size_t* log2_max_gc_pc) {
+ size_t local_gc_points = 0;
+ size_t max_insn = 0;
+ size_t max_ref_reg = -1;
+ const DexFile::CodeItem* code_item = method_verifier->CodeItem();
+ for (size_t i = 0; i < code_item->insns_size_in_code_units_; i++) {
+ if (method_verifier->GetInstructionFlags(i).IsCompileTimeInfoPoint()) {
+ local_gc_points++;
+ max_insn = i;
+ verifier::RegisterLine* line = method_verifier->GetRegLine(i);
+ max_ref_reg = line->GetMaxNonZeroReferenceReg(max_ref_reg);
+ }
+ }
+ *gc_points = local_gc_points;
+ *ref_bitmap_bits = max_ref_reg + 1; // If max register is 0 we need 1 bit to encode (ie +1).
+ size_t i = 0;
+ while ((1U << i) <= max_insn) {
+ i++;
+ }
+ *log2_max_gc_pc = i;
+}
+
+void VerifiedMethod::GenerateDevirtMap(verifier::MethodVerifier* method_verifier) {
+ // It is risky to rely on reg_types for sharpening in cases of soft
+ // verification, we might end up sharpening to a wrong implementation. Just abort.
+ if (method_verifier->HasFailures()) {
+ return;
+ }
+
+ const DexFile::CodeItem* code_item = method_verifier->CodeItem();
+ const uint16_t* insns = code_item->insns_;
+ const Instruction* inst = Instruction::At(insns);
+ const Instruction* end = Instruction::At(insns + code_item->insns_size_in_code_units_);
+
+ for (; inst < end; inst = inst->Next()) {
+ bool is_virtual = (inst->Opcode() == Instruction::INVOKE_VIRTUAL) ||
+ (inst->Opcode() == Instruction::INVOKE_VIRTUAL_RANGE);
+ bool is_interface = (inst->Opcode() == Instruction::INVOKE_INTERFACE) ||
+ (inst->Opcode() == Instruction::INVOKE_INTERFACE_RANGE);
+
+ if (!is_interface && !is_virtual) {
+ continue;
+ }
+ // Get reg type for register holding the reference to the object that will be dispatched upon.
+ uint32_t dex_pc = inst->GetDexPc(insns);
+ verifier::RegisterLine* line = method_verifier->GetRegLine(dex_pc);
+ bool is_range = (inst->Opcode() == Instruction::INVOKE_VIRTUAL_RANGE) ||
+ (inst->Opcode() == Instruction::INVOKE_INTERFACE_RANGE);
+ const verifier::RegType&
+ reg_type(line->GetRegisterType(is_range ? inst->VRegC_3rc() : inst->VRegC_35c()));
+
+ if (!reg_type.HasClass()) {
+ // We will compute devirtualization information only when we know the Class of the reg type.
+ continue;
+ }
+ mirror::Class* reg_class = reg_type.GetClass();
+ if (reg_class->IsInterface()) {
+ // We can't devirtualize when the known type of the register is an interface.
+ continue;
+ }
+ if (reg_class->IsAbstract() && !reg_class->IsArrayClass()) {
+ // We can't devirtualize abstract classes except on arrays of abstract classes.
+ continue;
+ }
+ mirror::ArtMethod* abstract_method = method_verifier->GetDexCache()->GetResolvedMethod(
+ is_range ? inst->VRegB_3rc() : inst->VRegB_35c());
+ if (abstract_method == NULL) {
+ // If the method is not found in the cache this means that it was never found
+ // by ResolveMethodAndCheckAccess() called when verifying invoke_*.
+ continue;
+ }
+ // Find the concrete method.
+ mirror::ArtMethod* concrete_method = NULL;
+ if (is_interface) {
+ concrete_method = reg_type.GetClass()->FindVirtualMethodForInterface(abstract_method);
+ }
+ if (is_virtual) {
+ concrete_method = reg_type.GetClass()->FindVirtualMethodForVirtual(abstract_method);
+ }
+ if (concrete_method == NULL || concrete_method->IsAbstract()) {
+ // In cases where concrete_method is not found, or is abstract, continue to the next invoke.
+ continue;
+ }
+ if (reg_type.IsPreciseReference() || concrete_method->IsFinal() ||
+ concrete_method->GetDeclaringClass()->IsFinal()) {
+ // If we knew exactly the class being dispatched upon, or if the target method cannot be
+ // overridden record the target to be used in the compiler driver.
+ MethodReference concrete_ref(
+ concrete_method->GetDeclaringClass()->GetDexCache()->GetDexFile(),
+ concrete_method->GetDexMethodIndex());
+ devirt_map_.Put(dex_pc, concrete_ref);
+ }
+ }
+}
+
+void VerifiedMethod::GenerateSafeCastSet(verifier::MethodVerifier* method_verifier) {
+ /*
+ * Walks over the method code and adds any cast instructions in which
+ * the type cast is implicit to a set, which is used in the code generation
+ * to elide these casts.
+ */
+ if (method_verifier->HasFailures()) {
+ return;
+ }
+ const DexFile::CodeItem* code_item = method_verifier->CodeItem();
+ const Instruction* inst = Instruction::At(code_item->insns_);
+ const Instruction* end = Instruction::At(code_item->insns_ +
+ code_item->insns_size_in_code_units_);
+
+ for (; inst < end; inst = inst->Next()) {
+ Instruction::Code code = inst->Opcode();
+ if ((code == Instruction::CHECK_CAST) || (code == Instruction::APUT_OBJECT)) {
+ uint32_t dex_pc = inst->GetDexPc(code_item->insns_);
+ const verifier::RegisterLine* line = method_verifier->GetRegLine(dex_pc);
+ bool is_safe_cast = false;
+ if (code == Instruction::CHECK_CAST) {
+ const verifier::RegType& reg_type(line->GetRegisterType(inst->VRegA_21c()));
+ const verifier::RegType& cast_type =
+ method_verifier->ResolveCheckedClass(inst->VRegB_21c());
+ is_safe_cast = cast_type.IsStrictlyAssignableFrom(reg_type);
+ } else {
+ const verifier::RegType& array_type(line->GetRegisterType(inst->VRegB_23x()));
+ // We only know its safe to assign to an array if the array type is precise. For example,
+ // an Object[] can have any type of object stored in it, but it may also be assigned a
+ // String[] in which case the stores need to be of Strings.
+ if (array_type.IsPreciseReference()) {
+ const verifier::RegType& value_type(line->GetRegisterType(inst->VRegA_23x()));
+ const verifier::RegType& component_type = method_verifier->GetRegTypeCache()
+ ->GetComponentType(array_type, method_verifier->GetClassLoader());
+ is_safe_cast = component_type.IsStrictlyAssignableFrom(value_type);
+ }
+ }
+ if (is_safe_cast) {
+ // Verify ordering for push_back() to the sorted vector.
+ DCHECK(safe_cast_set_.empty() || safe_cast_set_.back() < dex_pc);
+ safe_cast_set_.push_back(dex_pc);
+ }
+ }
+ }
+}
+
+} // namespace art
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