/*
* Copyright (C) 2017 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.
*/
#ifndef ART_COMPILER_LINKER_LINKER_PATCH_H_
#define ART_COMPILER_LINKER_LINKER_PATCH_H_
#include <iosfwd>
#include <stdint.h>
#include <android-base/logging.h>
#include "base/bit_utils.h"
#include "dex/method_reference.h"
namespace art {
class DexFile;
namespace linker {
class LinkerPatch {
public:
// Note: We explicitly specify the underlying type of the enum because GCC
// would otherwise select a bigger underlying type and then complain that
// 'art::LinkerPatch::patch_type_' is too small to hold all
// values of 'enum class art::LinkerPatch::Type'
// which is ridiculous given we have only a handful of values here. If we
// choose to squeeze the Type into fewer than 8 bits, we'll have to declare
// patch_type_ as an uintN_t and do explicit static_cast<>s.
//
// Note: Actual patching is instruction_set-dependent.
enum class Type : uint8_t {
kIntrinsicReference, // Boot image reference for an intrinsic, see IntrinsicObjects.
kDataBimgRelRo,
kMethodRelative,
kMethodBssEntry,
kCallRelative,
kTypeRelative,
kTypeBssEntry,
kStringRelative,
kStringBssEntry,
kBakerReadBarrierBranch,
};
static LinkerPatch IntrinsicReferencePatch(size_t literal_offset,
uint32_t pc_insn_offset,
uint32_t intrinsic_data) {
LinkerPatch patch(literal_offset, Type::kIntrinsicReference, /* target_dex_file= */ nullptr);
patch.intrinsic_data_ = intrinsic_data;
patch.pc_insn_offset_ = pc_insn_offset;
return patch;
}
static LinkerPatch DataBimgRelRoPatch(size_t literal_offset,
uint32_t pc_insn_offset,
uint32_t boot_image_offset) {
LinkerPatch patch(literal_offset, Type::kDataBimgRelRo, /* target_dex_file= */ nullptr);
patch.boot_image_offset_ = boot_image_offset;
patch.pc_insn_offset_ = pc_insn_offset;
return patch;
}
static LinkerPatch RelativeMethodPatch(size_t literal_offset,
const DexFile* target_dex_file,
uint32_t pc_insn_offset,
uint32_t target_method_idx) {
LinkerPatch patch(literal_offset, Type::kMethodRelative, target_dex_file);
patch.method_idx_ = target_method_idx;
patch.pc_insn_offset_ = pc_insn_offset;
return patch;
}
static LinkerPatch MethodBssEntryPatch(size_t literal_offset,
const DexFile* target_dex_file,
uint32_t pc_insn_offset,
uint32_t target_method_idx) {
LinkerPatch patch(literal_offset, Type::kMethodBssEntry, target_dex_file);
patch.method_idx_ = target_method_idx;
patch.pc_insn_offset_ = pc_insn_offset;
return patch;
}
static LinkerPatch RelativeCodePatch(size_t literal_offset,
const DexFile* target_dex_file,
uint32_t target_method_idx) {
LinkerPatch patch(literal_offset, Type::kCallRelative, target_dex_file);
patch.method_idx_ = target_method_idx;
return patch;
}
static LinkerPatch RelativeTypePatch(size_t literal_offset,
const DexFile* target_dex_file,
uint32_t pc_insn_offset,
uint32_t target_type_idx) {
LinkerPatch patch(literal_offset, Type::kTypeRelative, target_dex_file);
patch.type_idx_ = target_type_idx;
patch.pc_insn_offset_ = pc_insn_offset;
return patch;
}
static LinkerPatch TypeBssEntryPatch(size_t literal_offset,
const DexFile* target_dex_file,
uint32_t pc_insn_offset,
uint32_t target_type_idx) {
LinkerPatch patch(literal_offset, Type::kTypeBssEntry, target_dex_file);
patch.type_idx_ = target_type_idx;
patch.pc_insn_offset_ = pc_insn_offset;
return patch;
}
static LinkerPatch RelativeStringPatch(size_t literal_offset,
const DexFile* target_dex_file,
uint32_t pc_insn_offset,
uint32_t target_string_idx) {
LinkerPatch patch(literal_offset, Type::kStringRelative, target_dex_file);
patch.string_idx_ = target_string_idx;
patch.pc_insn_offset_ = pc_insn_offset;
return patch;
}
static LinkerPatch StringBssEntryPatch(size_t literal_offset,
const DexFile* target_dex_file,
uint32_t pc_insn_offset,
uint32_t target_string_idx) {
LinkerPatch patch(literal_offset, Type::kStringBssEntry, target_dex_file);
patch.string_idx_ = target_string_idx;
patch.pc_insn_offset_ = pc_insn_offset;
return patch;
}
static LinkerPatch BakerReadBarrierBranchPatch(size_t literal_offset,
uint32_t custom_value1 = 0u,
uint32_t custom_value2 = 0u) {
LinkerPatch patch(literal_offset,
Type::kBakerReadBarrierBranch,
/* target_dex_file= */ nullptr);
patch.baker_custom_value1_ = custom_value1;
patch.baker_custom_value2_ = custom_value2;
return patch;
}
LinkerPatch(const LinkerPatch& other) = default;
LinkerPatch& operator=(const LinkerPatch& other) = default;
size_t LiteralOffset() const {
return literal_offset_;
}
Type GetType() const {
return patch_type_;
}
uint32_t IntrinsicData() const {
DCHECK(patch_type_ == Type::kIntrinsicReference);
return intrinsic_data_;
}
uint32_t BootImageOffset() const {
DCHECK(patch_type_ == Type::kDataBimgRelRo);
return boot_image_offset_;
}
MethodReference TargetMethod() const {
DCHECK(patch_type_ == Type::kMethodRelative ||
patch_type_ == Type::kMethodBssEntry ||
patch_type_ == Type::kCallRelative);
return MethodReference(target_dex_file_, method_idx_);
}
const DexFile* TargetTypeDexFile() const {
DCHECK(patch_type_ == Type::kTypeRelative ||
patch_type_ == Type::kTypeBssEntry);
return target_dex_file_;
}
dex::TypeIndex TargetTypeIndex() const {
DCHECK(patch_type_ == Type::kTypeRelative ||
patch_type_ == Type::kTypeBssEntry);
return dex::TypeIndex(type_idx_);
}
const DexFile* TargetStringDexFile() const {
DCHECK(patch_type_ == Type::kStringRelative ||
patch_type_ == Type::kStringBssEntry);
return target_dex_file_;
}
dex::StringIndex TargetStringIndex() const {
DCHECK(patch_type_ == Type::kStringRelative ||
patch_type_ == Type::kStringBssEntry);
return dex::StringIndex(string_idx_);
}
uint32_t PcInsnOffset() const {
DCHECK(patch_type_ == Type::kIntrinsicReference ||
patch_type_ == Type::kDataBimgRelRo ||
patch_type_ == Type::kMethodRelative ||
patch_type_ == Type::kMethodBssEntry ||
patch_type_ == Type::kTypeRelative ||
patch_type_ == Type::kTypeBssEntry ||
patch_type_ == Type::kStringRelative ||
patch_type_ == Type::kStringBssEntry);
return pc_insn_offset_;
}
uint32_t GetBakerCustomValue1() const {
DCHECK(patch_type_ == Type::kBakerReadBarrierBranch);
return baker_custom_value1_;
}
uint32_t GetBakerCustomValue2() const {
DCHECK(patch_type_ == Type::kBakerReadBarrierBranch);
return baker_custom_value2_;
}
private:
LinkerPatch(size_t literal_offset, Type patch_type, const DexFile* target_dex_file)
: target_dex_file_(target_dex_file),
literal_offset_(literal_offset),
patch_type_(patch_type) {
cmp1_ = 0u;
cmp2_ = 0u;
// The compiler rejects methods that are too big, so the compiled code
// of a single method really shouln't be anywhere close to 16MiB.
DCHECK(IsUint<24>(literal_offset));
}
const DexFile* target_dex_file_;
// TODO: Clean up naming. Some patched locations are literals but others are not.
uint32_t literal_offset_ : 24; // Method code size up to 16MiB.
Type patch_type_ : 8;
union {
uint32_t cmp1_; // Used for relational operators.
uint32_t boot_image_offset_; // Data to write to the .data.bimg.rel.ro entry.
uint32_t method_idx_; // Method index for Call/Method patches.
uint32_t type_idx_; // Type index for Type patches.
uint32_t string_idx_; // String index for String patches.
uint32_t intrinsic_data_; // Data for IntrinsicObjects.
uint32_t baker_custom_value1_;
static_assert(sizeof(method_idx_) == sizeof(cmp1_), "needed by relational operators");
static_assert(sizeof(type_idx_) == sizeof(cmp1_), "needed by relational operators");
static_assert(sizeof(string_idx_) == sizeof(cmp1_), "needed by relational operators");
static_assert(sizeof(intrinsic_data_) == sizeof(cmp1_), "needed by relational operators");
static_assert(sizeof(baker_custom_value1_) == sizeof(cmp1_), "needed by relational operators");
};
union {
// Note: To avoid uninitialized padding on 64-bit systems, we use `size_t` for `cmp2_`.
// This allows a hashing function to treat an array of linker patches as raw memory.
size_t cmp2_; // Used for relational operators.
// Literal offset of the insn loading PC (same as literal_offset if it's the same insn,
// may be different if the PC-relative addressing needs multiple insns).
uint32_t pc_insn_offset_;
uint32_t baker_custom_value2_;
static_assert(sizeof(pc_insn_offset_) <= sizeof(cmp2_), "needed by relational operators");
static_assert(sizeof(baker_custom_value2_) <= sizeof(cmp2_), "needed by relational operators");
};
friend bool operator==(const LinkerPatch& lhs, const LinkerPatch& rhs);
friend bool operator<(const LinkerPatch& lhs, const LinkerPatch& rhs);
};
std::ostream& operator<<(std::ostream& os, const LinkerPatch::Type& type);
inline bool operator==(const LinkerPatch& lhs, const LinkerPatch& rhs) {
return lhs.literal_offset_ == rhs.literal_offset_ &&
lhs.patch_type_ == rhs.patch_type_ &&
lhs.target_dex_file_ == rhs.target_dex_file_ &&
lhs.cmp1_ == rhs.cmp1_ &&
lhs.cmp2_ == rhs.cmp2_;
}
inline bool operator<(const LinkerPatch& lhs, const LinkerPatch& rhs) {
return (lhs.literal_offset_ != rhs.literal_offset_) ? lhs.literal_offset_ < rhs.literal_offset_
: (lhs.patch_type_ != rhs.patch_type_) ? lhs.patch_type_ < rhs.patch_type_
: (lhs.target_dex_file_ != rhs.target_dex_file_) ? lhs.target_dex_file_ < rhs.target_dex_file_
: (lhs.cmp1_ != rhs.cmp1_) ? lhs.cmp1_ < rhs.cmp1_
: lhs.cmp2_ < rhs.cmp2_;
}
} // namespace linker
} // namespace art
#endif // ART_COMPILER_LINKER_LINKER_PATCH_H_