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23623a08d6
C++ style guides I am aware of recommend specifically preferring = syntax for any classes with fairly obvious constructors[^0] that do not perform any complicated logic in their constructor. I contend that all constructors that the `rustc_llvm` code uses qualify. This has only become more common since C++ 17 guaranteed many cases of copy initialization elision. The other detail is that I tried to ask another contributor with infinitely more C++ experience than me (i.e. any) what this constructor syntax was, and they thought it was a macro. I know of no other language that has adopted this same syntax. As the rustc codebase features many contributors experienced in many other languages, using a less... unique... style has many other benefits in making this code more lucid and maintainable, which is something it direly needs. [^0]: e.g. https://abseil.io/tips/88
99 lines
3.5 KiB
C++
99 lines
3.5 KiB
C++
// Derived from code in LLVM, which is:
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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// Derived from:
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// * https://github.com/llvm/llvm-project/blob/8ef3e895ad8ab1724e2b87cabad1dacdc7a397a3/llvm/include/llvm/Object/ArchiveWriter.h
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// * https://github.com/llvm/llvm-project/blob/8ef3e895ad8ab1724e2b87cabad1dacdc7a397a3/llvm/lib/Object/ArchiveWriter.cpp
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#include "SuppressLLVMWarnings.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/Object/ObjectFile.h"
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#include <llvm/Support/raw_ostream.h>
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using namespace llvm;
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using namespace llvm::sys;
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using namespace llvm::object;
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static bool isArchiveSymbol(const object::BasicSymbolRef &S) {
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Expected<uint32_t> SymFlagsOrErr = S.getFlags();
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if (!SymFlagsOrErr)
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// FIXME: Actually report errors helpfully.
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report_fatal_error(SymFlagsOrErr.takeError());
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if (*SymFlagsOrErr & object::SymbolRef::SF_FormatSpecific)
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return false;
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if (!(*SymFlagsOrErr & object::SymbolRef::SF_Global))
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return false;
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if (*SymFlagsOrErr & object::SymbolRef::SF_Undefined)
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return false;
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return true;
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}
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typedef void *(*LLVMRustGetSymbolsCallback)(void *, const char *);
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typedef void *(*LLVMRustGetSymbolsErrorCallback)(const char *);
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// Note: This is implemented in C++ instead of using the C api from Rust as IRObjectFile doesn't
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// implement getSymbolName, only printSymbolName, which is inaccessible from the C api.
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extern "C" void *LLVMRustGetSymbols(
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char *BufPtr, size_t BufLen, void *State, LLVMRustGetSymbolsCallback Callback,
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LLVMRustGetSymbolsErrorCallback ErrorCallback) {
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std::unique_ptr<MemoryBuffer> Buf =
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MemoryBuffer::getMemBuffer(StringRef(BufPtr, BufLen), StringRef("LLVMRustGetSymbolsObject"),
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false);
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SmallString<0> SymNameBuf;
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auto SymName = raw_svector_ostream(SymNameBuf);
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// In the scenario when LLVMContext is populated SymbolicFile will contain a
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// reference to it, thus SymbolicFile should be destroyed first.
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LLVMContext Context;
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std::unique_ptr<object::SymbolicFile> Obj;
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const file_magic Type = identify_magic(Buf->getBuffer());
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if (!object::SymbolicFile::isSymbolicFile(Type, &Context)) {
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return 0;
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}
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if (Type == file_magic::bitcode) {
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auto ObjOrErr = object::SymbolicFile::createSymbolicFile(
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Buf->getMemBufferRef(), file_magic::bitcode, &Context);
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if (!ObjOrErr) {
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Error E = ObjOrErr.takeError();
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SmallString<0> ErrorBuf;
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auto Error = raw_svector_ostream(ErrorBuf);
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Error << E << '\0';
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return ErrorCallback(Error.str().data());
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}
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Obj = std::move(*ObjOrErr);
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} else {
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auto ObjOrErr = object::SymbolicFile::createSymbolicFile(Buf->getMemBufferRef());
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if (!ObjOrErr) {
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Error E = ObjOrErr.takeError();
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SmallString<0> ErrorBuf;
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auto Error = raw_svector_ostream(ErrorBuf);
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Error << E << '\0';
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return ErrorCallback(Error.str().data());
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}
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Obj = std::move(*ObjOrErr);
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}
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for (const object::BasicSymbolRef &S : Obj->symbols()) {
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if (!isArchiveSymbol(S))
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continue;
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if (Error E = S.printName(SymName)) {
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SmallString<0> ErrorBuf;
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auto Error = raw_svector_ostream(ErrorBuf);
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Error << E << '\0';
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return ErrorCallback(Error.str().data());
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}
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SymName << '\0';
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if (void *E = Callback(State, SymNameBuf.str().data())) {
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return E;
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}
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SymNameBuf.clear();
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}
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return 0;
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}
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