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|
//===- tools/dsymutil/SwiftModule.cpp -------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Bitcode/BitcodeReader.h"
#include "llvm/Bitcode/LLVMBitCodes.h"
#include "llvm/Bitstream/BitCodes.h"
#include "llvm/Bitstream/BitstreamReader.h"
namespace {
// Copied from swift/lib/Serialization/ModuleFormat.h
constexpr unsigned char SWIFTMODULE_SIGNATURE[] = {0xE2, 0x9C, 0xA8, 0x0E};
constexpr uint16_t expectedMajorVersion = 0;
constexpr unsigned MODULE_BLOCK_ID = llvm::bitc::FIRST_APPLICATION_BLOCKID;
constexpr unsigned CONTROL_BLOCK_ID = llvm::bitc::FIRST_APPLICATION_BLOCKID + 1;
constexpr unsigned METADATA = 1;
constexpr unsigned OPTIONS_BLOCK_ID = llvm::bitc::FIRST_APPLICATION_BLOCKID + 8;
constexpr unsigned IS_BUILT_FROM_INTERFACE = 11;
llvm::Error checkModuleSignature(llvm::BitstreamCursor &cursor,
llvm::ArrayRef<unsigned char> signature) {
for (unsigned char byte : signature) {
if (cursor.AtEndOfStream())
return llvm::createStringError("malformed bitstream");
llvm::Expected<llvm::SimpleBitstreamCursor::word_t> maybeRead =
cursor.Read(8);
if (!maybeRead)
return maybeRead.takeError();
if (maybeRead.get() != byte)
return llvm::createStringError("malformed bitstream");
}
return llvm::Error::success();
}
llvm::Error enterTopLevelModuleBlock(llvm::BitstreamCursor &cursor,
unsigned ID) {
llvm::Expected<llvm::BitstreamEntry> maybeNext = cursor.advance();
if (!maybeNext)
return maybeNext.takeError();
llvm::BitstreamEntry next = maybeNext.get();
if (next.Kind != llvm::BitstreamEntry::SubBlock)
return llvm::createStringError("malformed bitstream");
if (next.ID == llvm::bitc::BLOCKINFO_BLOCK_ID) {
if (cursor.SkipBlock())
return llvm::createStringError("malformed bitstream");
return enterTopLevelModuleBlock(cursor, ID);
}
if (next.ID != ID)
return llvm::createStringError("malformed bitstream");
if (llvm::Error Err = cursor.EnterSubBlock(ID))
return Err;
return llvm::Error::success();
}
llvm::Expected<bool>
readOptionsBlock(llvm::BitstreamCursor &cursor,
llvm::SmallVectorImpl<uint64_t> &scratch) {
bool is_built_from_interface = false;
while (!cursor.AtEndOfStream()) {
llvm::Expected<llvm::BitstreamEntry> maybeEntry = cursor.advance();
if (!maybeEntry)
return maybeEntry.takeError();
llvm::BitstreamEntry entry = maybeEntry.get();
if (entry.Kind == llvm::BitstreamEntry::EndBlock)
break;
if (entry.Kind == llvm::BitstreamEntry::Error)
return llvm::createStringError("malformed bitstream");
if (entry.Kind == llvm::BitstreamEntry::SubBlock) {
if (cursor.SkipBlock())
return llvm::createStringError("malformed bitstream");
continue;
}
scratch.clear();
llvm::StringRef blobData;
llvm::Expected<unsigned> maybeKind =
cursor.readRecord(entry.ID, scratch, &blobData);
if (!maybeKind)
return maybeKind.takeError();
unsigned kind = maybeKind.get();
switch (kind) {
case IS_BUILT_FROM_INTERFACE:
is_built_from_interface = true;
continue;
default:
continue;
}
}
return is_built_from_interface;
}
llvm::Expected<bool>
parseControlBlock(llvm::BitstreamCursor &cursor,
llvm::SmallVectorImpl<uint64_t> &scratch) {
// The control block is malformed until we've at least read a major version
// number.
bool versionSeen = false;
while (!cursor.AtEndOfStream()) {
llvm::Expected<llvm::BitstreamEntry> maybeEntry = cursor.advance();
if (!maybeEntry)
return maybeEntry.takeError();
llvm::BitstreamEntry entry = maybeEntry.get();
if (entry.Kind == llvm::BitstreamEntry::EndBlock)
break;
if (entry.Kind == llvm::BitstreamEntry::Error)
return llvm::createStringError("malformed bitstream");
if (entry.Kind == llvm::BitstreamEntry::SubBlock) {
if (entry.ID == OPTIONS_BLOCK_ID) {
if (llvm::Error Err = cursor.EnterSubBlock(OPTIONS_BLOCK_ID))
return Err;
return readOptionsBlock(cursor, scratch);
} else {
// Unknown metadata sub-block, possibly for use by a future version of
// the module format.
if (cursor.SkipBlock())
return llvm::createStringError("malformed bitstream");
}
continue;
}
scratch.clear();
llvm::StringRef blobData;
llvm::Expected<unsigned> maybeKind =
cursor.readRecord(entry.ID, scratch, &blobData);
if (!maybeKind)
return maybeKind.takeError();
unsigned kind = maybeKind.get();
if (kind == METADATA) {
if (versionSeen)
return llvm::createStringError("multiple metadata blocks");
uint16_t versionMajor = scratch[0];
if (versionMajor != expectedMajorVersion)
return llvm::createStringError("unsupported module version");
versionSeen = true;
}
}
return llvm::createStringError("could not find control block");
}
} // namespace
llvm::Expected<bool> IsBuiltFromSwiftInterface(llvm::StringRef data) {
llvm::BitstreamCursor cursor(data);
if (llvm::Error Err = checkModuleSignature(cursor, SWIFTMODULE_SIGNATURE))
return llvm::joinErrors(
llvm::createStringError("could not check signature"), std::move(Err));
if (llvm::Error Err = enterTopLevelModuleBlock(cursor, MODULE_BLOCK_ID))
return llvm::joinErrors(
llvm::createStringError("could not enter top level block"),
std::move(Err));
llvm::BitstreamEntry topLevelEntry;
llvm::SmallVector<uint64_t, 32> scratch;
while (!cursor.AtEndOfStream()) {
llvm::Expected<llvm::BitstreamEntry> maybeEntry =
cursor.advance(llvm::BitstreamCursor::AF_DontPopBlockAtEnd);
if (!maybeEntry)
return maybeEntry.takeError();
topLevelEntry = maybeEntry.get();
if (topLevelEntry.Kind != llvm::BitstreamEntry::SubBlock)
break;
if (topLevelEntry.ID == CONTROL_BLOCK_ID) {
if (llvm::Error Err = cursor.EnterSubBlock(CONTROL_BLOCK_ID))
return Err;
return parseControlBlock(cursor, scratch);
}
}
return llvm::createStringError("no control block found");
}
|
