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| 1 | +//===- tools/dsymutil/SwiftModule.cpp -------------------------------------===// |
| 2 | +// |
| 3 | +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | +// See https://llvm.org/LICENSE.txt for license information. |
| 5 | +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | +// |
| 7 | +//===----------------------------------------------------------------------===// |
| 8 | + |
| 9 | +#include "llvm/Bitcode/BitcodeReader.h" |
| 10 | +#include "llvm/Bitcode/LLVMBitCodes.h" |
| 11 | +#include "llvm/Bitstream/BitCodes.h" |
| 12 | +#include "llvm/Bitstream/BitstreamReader.h" |
| 13 | + |
| 14 | +namespace { |
| 15 | +// Copied from swift/lib/Serialization/ModuleFormat.h |
| 16 | +constexpr unsigned char SWIFTMODULE_SIGNATURE[] = {0xE2, 0x9C, 0xA8, 0x0E}; |
| 17 | +constexpr uint16_t expectedMajorVersion = 0; |
| 18 | +constexpr unsigned MODULE_BLOCK_ID = llvm::bitc::FIRST_APPLICATION_BLOCKID; |
| 19 | +constexpr unsigned CONTROL_BLOCK_ID = llvm::bitc::FIRST_APPLICATION_BLOCKID + 1; |
| 20 | +constexpr unsigned METADATA = 1; |
| 21 | +constexpr unsigned OPTIONS_BLOCK_ID = llvm::bitc::FIRST_APPLICATION_BLOCKID + 8; |
| 22 | +constexpr unsigned IS_BUILT_FROM_INTERFACE = 11; |
| 23 | + |
| 24 | +llvm::Error checkModuleSignature(llvm::BitstreamCursor &cursor, |
| 25 | + llvm::ArrayRef<unsigned char> signature) { |
| 26 | + for (unsigned char byte : signature) { |
| 27 | + if (cursor.AtEndOfStream()) |
| 28 | + return llvm::createStringError("malformed bitstream"); |
| 29 | + llvm::Expected<llvm::SimpleBitstreamCursor::word_t> maybeRead = |
| 30 | + cursor.Read(8); |
| 31 | + if (!maybeRead) |
| 32 | + return maybeRead.takeError(); |
| 33 | + if (maybeRead.get() != byte) |
| 34 | + return llvm::createStringError("malformed bitstream"); |
| 35 | + } |
| 36 | + return llvm::Error::success(); |
| 37 | +} |
| 38 | + |
| 39 | +llvm::Error enterTopLevelModuleBlock(llvm::BitstreamCursor &cursor, |
| 40 | + unsigned ID) { |
| 41 | + llvm::Expected<llvm::BitstreamEntry> maybeNext = cursor.advance(); |
| 42 | + if (!maybeNext) |
| 43 | + return maybeNext.takeError(); |
| 44 | + llvm::BitstreamEntry next = maybeNext.get(); |
| 45 | + |
| 46 | + if (next.Kind != llvm::BitstreamEntry::SubBlock) |
| 47 | + return llvm::createStringError("malformed bitstream"); |
| 48 | + |
| 49 | + if (next.ID == llvm::bitc::BLOCKINFO_BLOCK_ID) { |
| 50 | + if (cursor.SkipBlock()) |
| 51 | + return llvm::createStringError("malformed bitstream"); |
| 52 | + return enterTopLevelModuleBlock(cursor, ID); |
| 53 | + } |
| 54 | + |
| 55 | + if (next.ID != ID) |
| 56 | + return llvm::createStringError("malformed bitstream"); |
| 57 | + |
| 58 | + if (llvm::Error Err = cursor.EnterSubBlock(ID)) |
| 59 | + return Err; |
| 60 | + |
| 61 | + return llvm::Error::success(); |
| 62 | +} |
| 63 | + |
| 64 | +llvm::Expected<bool> |
| 65 | +readOptionsBlock(llvm::BitstreamCursor &cursor, |
| 66 | + llvm::SmallVectorImpl<uint64_t> &scratch) { |
| 67 | + bool is_built_from_interface = false; |
| 68 | + while (!cursor.AtEndOfStream()) { |
| 69 | + llvm::Expected<llvm::BitstreamEntry> maybeEntry = cursor.advance(); |
| 70 | + if (!maybeEntry) |
| 71 | + return maybeEntry.takeError(); |
| 72 | + |
| 73 | + llvm::BitstreamEntry entry = maybeEntry.get(); |
| 74 | + if (entry.Kind == llvm::BitstreamEntry::EndBlock) |
| 75 | + break; |
| 76 | + |
| 77 | + if (entry.Kind == llvm::BitstreamEntry::Error) |
| 78 | + return llvm::createStringError("malformed bitstream"); |
| 79 | + |
| 80 | + if (entry.Kind == llvm::BitstreamEntry::SubBlock) { |
| 81 | + if (cursor.SkipBlock()) |
| 82 | + return llvm::createStringError("malformed bitstream"); |
| 83 | + continue; |
| 84 | + } |
| 85 | + |
| 86 | + scratch.clear(); |
| 87 | + llvm::StringRef blobData; |
| 88 | + llvm::Expected<unsigned> maybeKind = |
| 89 | + cursor.readRecord(entry.ID, scratch, &blobData); |
| 90 | + if (!maybeKind) |
| 91 | + return maybeKind.takeError(); |
| 92 | + unsigned kind = maybeKind.get(); |
| 93 | + switch (kind) { |
| 94 | + case IS_BUILT_FROM_INTERFACE: |
| 95 | + is_built_from_interface = true; |
| 96 | + continue; |
| 97 | + default: |
| 98 | + continue; |
| 99 | + } |
| 100 | + } |
| 101 | + return is_built_from_interface; |
| 102 | +} |
| 103 | + |
| 104 | +llvm::Expected<bool> |
| 105 | +parseControlBlock(llvm::BitstreamCursor &cursor, |
| 106 | + llvm::SmallVectorImpl<uint64_t> &scratch) { |
| 107 | + // The control block is malformed until we've at least read a major version |
| 108 | + // number. |
| 109 | + bool versionSeen = false; |
| 110 | + |
| 111 | + while (!cursor.AtEndOfStream()) { |
| 112 | + llvm::Expected<llvm::BitstreamEntry> maybeEntry = cursor.advance(); |
| 113 | + if (!maybeEntry) |
| 114 | + return maybeEntry.takeError(); |
| 115 | + |
| 116 | + llvm::BitstreamEntry entry = maybeEntry.get(); |
| 117 | + if (entry.Kind == llvm::BitstreamEntry::EndBlock) |
| 118 | + break; |
| 119 | + |
| 120 | + if (entry.Kind == llvm::BitstreamEntry::Error) |
| 121 | + return llvm::createStringError("malformed bitstream"); |
| 122 | + |
| 123 | + if (entry.Kind == llvm::BitstreamEntry::SubBlock) { |
| 124 | + if (entry.ID == OPTIONS_BLOCK_ID) { |
| 125 | + if (llvm::Error Err = cursor.EnterSubBlock(OPTIONS_BLOCK_ID)) |
| 126 | + return Err; |
| 127 | + |
| 128 | + return readOptionsBlock(cursor, scratch); |
| 129 | + } else { |
| 130 | + // Unknown metadata sub-block, possibly for use by a future version of |
| 131 | + // the module format. |
| 132 | + if (cursor.SkipBlock()) |
| 133 | + return llvm::createStringError("malformed bitstream"); |
| 134 | + } |
| 135 | + continue; |
| 136 | + } |
| 137 | + |
| 138 | + scratch.clear(); |
| 139 | + llvm::StringRef blobData; |
| 140 | + llvm::Expected<unsigned> maybeKind = |
| 141 | + cursor.readRecord(entry.ID, scratch, &blobData); |
| 142 | + if (!maybeKind) |
| 143 | + return maybeKind.takeError(); |
| 144 | + |
| 145 | + unsigned kind = maybeKind.get(); |
| 146 | + if (kind == METADATA) { |
| 147 | + if (versionSeen) |
| 148 | + return llvm::createStringError("multiple metadata blocks"); |
| 149 | + |
| 150 | + uint16_t versionMajor = scratch[0]; |
| 151 | + if (versionMajor != expectedMajorVersion) |
| 152 | + return llvm::createStringError("unsupported module version"); |
| 153 | + |
| 154 | + versionSeen = true; |
| 155 | + } |
| 156 | + } |
| 157 | + return llvm::createStringError("could not find control block"); |
| 158 | +} |
| 159 | + |
| 160 | +} // namespace |
| 161 | + |
| 162 | +llvm::Expected<bool> IsBuiltFromSwiftInterface(llvm::StringRef data) { |
| 163 | + llvm::BitstreamCursor cursor(data); |
| 164 | + if (llvm::Error Err = checkModuleSignature(cursor, SWIFTMODULE_SIGNATURE)) |
| 165 | + return llvm::joinErrors( |
| 166 | + llvm::createStringError("could not check signature"), std::move(Err)); |
| 167 | + if (llvm::Error Err = enterTopLevelModuleBlock(cursor, MODULE_BLOCK_ID)) |
| 168 | + return llvm::joinErrors( |
| 169 | + llvm::createStringError("could not enter top level block"), |
| 170 | + std::move(Err)); |
| 171 | + |
| 172 | + llvm::BitstreamEntry topLevelEntry; |
| 173 | + llvm::SmallVector<uint64_t, 32> scratch; |
| 174 | + |
| 175 | + while (!cursor.AtEndOfStream()) { |
| 176 | + llvm::Expected<llvm::BitstreamEntry> maybeEntry = |
| 177 | + cursor.advance(llvm::BitstreamCursor::AF_DontPopBlockAtEnd); |
| 178 | + if (!maybeEntry) |
| 179 | + return maybeEntry.takeError(); |
| 180 | + |
| 181 | + topLevelEntry = maybeEntry.get(); |
| 182 | + if (topLevelEntry.Kind != llvm::BitstreamEntry::SubBlock) |
| 183 | + break; |
| 184 | + |
| 185 | + if (topLevelEntry.ID == CONTROL_BLOCK_ID) { |
| 186 | + if (llvm::Error Err = cursor.EnterSubBlock(CONTROL_BLOCK_ID)) |
| 187 | + return Err; |
| 188 | + return parseControlBlock(cursor, scratch); |
| 189 | + } |
| 190 | + } |
| 191 | + return llvm::createStringError("no control block found"); |
| 192 | +} |
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