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| 1 // Copyright 2015 The Chromium Authors. All rights reserved. | 1 // Copyright 2015 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 #ifndef COURGETTE_IMAGE_UTILS_H_ | 5 #ifndef COURGETTE_IMAGE_UTILS_H_ |
| 6 #define COURGETTE_IMAGE_UTILS_H_ | 6 #define COURGETTE_IMAGE_UTILS_H_ |
| 7 | 7 |
| 8 #include <stddef.h> | 8 #include <stddef.h> |
| 9 #include <stdint.h> | 9 #include <stdint.h> |
| 10 | 10 |
| 11 // COURGETTE_HISTOGRAM_TARGETS prints out a histogram of how frequently | 11 // COURGETTE_HISTOGRAM_TARGETS prints out a histogram of how frequently |
| 12 // different target addresses are referenced. Purely for debugging. | 12 // different target addresses are referenced. Purely for debugging. |
| 13 #define COURGETTE_HISTOGRAM_TARGETS 0 | 13 #define COURGETTE_HISTOGRAM_TARGETS 0 |
| 14 | 14 |
| 15 namespace courgette { | 15 namespace courgette { |
| 16 | 16 |
| 17 // There are several ways to reason about addresses in an image: | 17 typedef uint32_t RVA; |
| 18 // - File Offset: Position relative to start of image. | |
| 19 // - VA (Virtual Address): Virtual memory address of a loaded image. This is | |
| 20 // subject to relocation by the OS. | |
| 21 // - RVA (Relative Virtual Address): VA relative to some base address. This is | |
| 22 // the preferred way to specify pointers in an image. Two ways to encode RVA | |
| 23 // are: | |
| 24 // - abs32: RVA value is encoded directly. | |
| 25 // - rel32: RVA is encoded as offset from an instruction address. This is | |
| 26 // commonly used for relative branch/call opcodes. | |
| 27 // Courgette operates on File Offsets and RVAs only. | |
| 28 | |
| 29 using RVA = uint32_t; | |
| 30 const RVA kUnassignedRVA = 0xFFFFFFFFU; | 18 const RVA kUnassignedRVA = 0xFFFFFFFFU; |
| 31 const RVA kNoRVA = 0xFFFFFFFFU; | |
| 32 | |
| 33 using FileOffset = size_t; | |
| 34 const FileOffset kNoFileOffset = UINTPTR_MAX; | |
| 35 | |
| 36 // An interface for {File Offset, RVA, pointer to image data} translation. | |
| 37 class AddressTranslator { | |
| 38 public: | |
| 39 // Returns the RVA corresponding to |file_offset|, or kNoRVA if nonexistent. | |
| 40 virtual RVA FileOffsetToRVA(FileOffset file_offset) const = 0; | |
| 41 | |
| 42 // Returns the file offset corresponding to |rva|, or kNoFileOffset if | |
| 43 // nonexistent. | |
| 44 virtual FileOffset RVAToFileOffset(RVA rva) const = 0; | |
| 45 | |
| 46 // Returns the pointer to the image data for |file_offset|. Assumes that | |
| 47 // 0 <= |file_offset| <= image size. If |file_offset| == image, the resulting | |
| 48 // pointer is an end bound for iteration that should never be dereferenced. | |
| 49 virtual const uint8_t* FileOffsetToPointer(FileOffset file_offset) const = 0; | |
| 50 | |
| 51 // Returns the pointer to the image data for |rva|, or null if |rva| is | |
| 52 // invalid. | |
| 53 virtual const uint8_t* RVAToPointer(RVA rva) const = 0; | |
| 54 }; | |
| 55 | 19 |
| 56 // A Label is a symbolic reference to an address. Unlike a conventional | 20 // A Label is a symbolic reference to an address. Unlike a conventional |
| 57 // assembly language, we always know the address. The address will later be | 21 // assembly language, we always know the address. The address will later be |
| 58 // stored in a table and the Label will be replaced with the index into the | 22 // stored in a table and the Label will be replaced with the index into the |
| 59 // table. | 23 // table. |
| 60 // TODO(huangs): Make this a struct, and remove "_" from member names. | 24 // TODO(huangs): Make this a struct, and remove "_" from member names. |
| 61 class Label { | 25 class Label { |
| 62 public: | 26 public: |
| 63 enum : int { kNoIndex = -1 }; | 27 enum : int { kNoIndex = -1 }; |
| 64 explicit Label(RVA rva) : rva_(rva) {} | 28 explicit Label(RVA rva) : rva_(rva) {} |
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| 97 return *reinterpret_cast<const uint32_t*>(address); | 61 return *reinterpret_cast<const uint32_t*>(address); |
| 98 } | 62 } |
| 99 | 63 |
| 100 inline uint64_t Read64LittleEndian(const void* address) { | 64 inline uint64_t Read64LittleEndian(const void* address) { |
| 101 return *reinterpret_cast<const uint64_t*>(address); | 65 return *reinterpret_cast<const uint64_t*>(address); |
| 102 } | 66 } |
| 103 | 67 |
| 104 } // namespace courgette | 68 } // namespace courgette |
| 105 | 69 |
| 106 #endif // COURGETTE_IMAGE_UTILS_H_ | 70 #endif // COURGETTE_IMAGE_UTILS_H_ |
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