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swift-mirror/lib/ASTSectionImporter/ASTSectionImporter.cpp

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//===--- ASTSectionImporter.cpp - Import AST Section Modules --------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements support for loading modules serialized into a
// Mach-O AST section into Swift.
//
//===----------------------------------------------------------------------===//
#include "swift/Serialization/SerializedModuleLoader.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
namespace swift {
bool parseASTSection(SerializedModuleLoader* SML,
const std::unique_ptr<llvm::MemoryBuffer> &MemoryBuffer,
SmallVectorImpl<std::string> &foundModules) {
struct apple_ast_hdr {
uint32_t version;
uint32_t nmods;
};
struct module_header {
uint64_t bitstream_ofs;
uint64_t bitstream_size;
uint64_t name_ofs;
uint32_t language;
uint32_t flags;
};
if (MemoryBuffer->getBufferSize() < sizeof(struct apple_ast_hdr)
+ sizeof(struct module_header)) {
llvm::dbgs() << "__apple_ast section is too small.\n";
return false;
}
size_t size = MemoryBuffer->getBufferSize();
const char *data = MemoryBuffer->getBufferStart();
auto apple_ast_hdr = reinterpret_cast<const struct apple_ast_hdr *>(data);
if (apple_ast_hdr->version != 1) {
llvm::dbgs() << "Unsupported __apple_ast section version.\n";
return false;
}
// Iterate over all AST modules.
for (uint32_t i = 0; i < apple_ast_hdr->nmods; ++i) {
auto mh = reinterpret_cast<const struct module_header *>
(data+sizeof(apple_ast_hdr));
if (mh->language != dwarf::DW_LANG_Swift)
continue;
// Get the access path.
if (mh->name_ofs + 4 > size) return false;
auto nchars = *reinterpret_cast<const uint32_t *>(data + mh->name_ofs);
if (mh->name_ofs+sizeof(nchars) > size) return false;
assert(nchars < (2 << 10) && "path failed sanity check");
llvm::StringRef AccessPath(data+mh->name_ofs+sizeof(nchars), nchars);
// loadModule() wants to take ownership of the input memory buffer.
// Copy the bitstream into a new memory buffer.
if (mh->bitstream_ofs + mh->bitstream_size > size) return false;
auto mem = llvm::StringRef(data+mh->bitstream_ofs, mh->bitstream_size);
auto bitstream = llvm::MemoryBuffer::getMemBufferCopy(mem, AccessPath);
// Register the memory buffer.
SML->registerMemoryBuffer(AccessPath,
std::unique_ptr<llvm::MemoryBuffer>(bitstream));
foundModules.push_back(AccessPath);
}
return true;
}
}