compiler/linker/linker_patch.h - platform/art - Git at Google

 /*
  * 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_
	/*
	* 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_