164 lines · cpp
1//===- WasmObjcopy.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-exception6//7//===----------------------------------------------------------------------===//8 9#include "llvm/ObjCopy/wasm/WasmObjcopy.h"10#include "WasmObject.h"11#include "WasmReader.h"12#include "WasmWriter.h"13#include "llvm/ObjCopy/CommonConfig.h"14#include "llvm/Support/Errc.h"15#include "llvm/Support/FileOutputBuffer.h"16 17namespace llvm {18namespace objcopy {19namespace wasm {20 21using namespace object;22using SectionPred = std::function<bool(const Section &Sec)>;23 24static bool isDebugSection(const Section &Sec) {25 return Sec.Name.starts_with(".debug") || Sec.Name.starts_with("reloc..debug");26}27 28static bool isLinkerSection(const Section &Sec) {29 return Sec.Name.starts_with("reloc.") || Sec.Name == "linking";30}31 32static bool isNameSection(const Section &Sec) { return Sec.Name == "name"; }33 34// Sections which are known to be "comments" or informational and do not affect35// program semantics.36static bool isCommentSection(const Section &Sec) {37 return Sec.Name == "producers";38}39 40static Error dumpSectionToFile(StringRef SecName, StringRef Filename,41 StringRef InputFilename, Object &Obj) {42 for (const Section &Sec : Obj.Sections) {43 if (Sec.Name == SecName) {44 ArrayRef<uint8_t> Contents = Sec.Contents;45 Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr =46 FileOutputBuffer::create(Filename, Contents.size());47 if (!BufferOrErr)48 return createFileError(Filename, BufferOrErr.takeError());49 std::unique_ptr<FileOutputBuffer> Buf = std::move(*BufferOrErr);50 llvm::copy(Contents, Buf->getBufferStart());51 if (Error E = Buf->commit())52 return createFileError(Filename, std::move(E));53 return Error::success();54 }55 }56 return createFileError(Filename, errc::invalid_argument,57 "section '%s' not found", SecName.str().c_str());58}59 60static void removeSections(const CommonConfig &Config, Object &Obj) {61 SectionPred RemovePred = [](const Section &) { return false; };62 63 // Explicitly-requested sections.64 if (!Config.ToRemove.empty()) {65 RemovePred = [&Config](const Section &Sec) {66 return Config.ToRemove.matches(Sec.Name);67 };68 }69 70 if (Config.StripDebug) {71 RemovePred = [RemovePred](const Section &Sec) {72 return RemovePred(Sec) || isDebugSection(Sec);73 };74 }75 76 if (Config.StripAll) {77 RemovePred = [RemovePred](const Section &Sec) {78 return RemovePred(Sec) || isDebugSection(Sec) || isLinkerSection(Sec) ||79 isNameSection(Sec) || isCommentSection(Sec);80 };81 }82 83 if (Config.OnlyKeepDebug) {84 RemovePred = [&Config](const Section &Sec) {85 // Keep debug sections, unless explicitly requested to remove.86 // Remove everything else, including known sections.87 return Config.ToRemove.matches(Sec.Name) || !isDebugSection(Sec);88 };89 }90 91 if (!Config.OnlySection.empty()) {92 RemovePred = [&Config](const Section &Sec) {93 // Explicitly keep these sections regardless of previous removes.94 // Remove everything else, inluding known sections.95 return !Config.OnlySection.matches(Sec.Name);96 };97 }98 99 if (!Config.KeepSection.empty()) {100 RemovePred = [&Config, RemovePred](const Section &Sec) {101 // Explicitly keep these sections regardless of previous removes.102 if (Config.KeepSection.matches(Sec.Name))103 return false;104 // Otherwise defer to RemovePred.105 return RemovePred(Sec);106 };107 }108 109 Obj.removeSections(RemovePred);110}111 112static Error handleArgs(const CommonConfig &Config, Object &Obj) {113 // Only support AddSection, DumpSection, RemoveSection for now.114 for (StringRef Flag : Config.DumpSection) {115 StringRef SecName;116 StringRef FileName;117 std::tie(SecName, FileName) = Flag.split("=");118 if (Error E =119 dumpSectionToFile(SecName, FileName, Config.InputFilename, Obj))120 return E;121 }122 123 removeSections(Config, Obj);124 125 for (const NewSectionInfo &NewSection : Config.AddSection) {126 Section Sec;127 Sec.SectionType = llvm::wasm::WASM_SEC_CUSTOM;128 Sec.Name = NewSection.SectionName;129 130 llvm::StringRef InputData =131 llvm::StringRef(NewSection.SectionData->getBufferStart(),132 NewSection.SectionData->getBufferSize());133 std::unique_ptr<MemoryBuffer> BufferCopy = MemoryBuffer::getMemBufferCopy(134 InputData, NewSection.SectionData->getBufferIdentifier());135 Sec.Contents = ArrayRef<uint8_t>(136 reinterpret_cast<const uint8_t *>(BufferCopy->getBufferStart()),137 BufferCopy->getBufferSize());138 139 Obj.addSectionWithOwnedContents(Sec, std::move(BufferCopy));140 }141 142 return Error::success();143}144 145Error executeObjcopyOnBinary(const CommonConfig &Config, const WasmConfig &,146 object::WasmObjectFile &In, raw_ostream &Out) {147 Reader TheReader(In);148 Expected<std::unique_ptr<Object>> ObjOrErr = TheReader.create();149 if (!ObjOrErr)150 return createFileError(Config.InputFilename, ObjOrErr.takeError());151 Object *Obj = ObjOrErr->get();152 assert(Obj && "Unable to deserialize Wasm object");153 if (Error E = handleArgs(Config, *Obj))154 return E;155 Writer TheWriter(*Obj, Out);156 if (Error E = TheWriter.write())157 return createFileError(Config.OutputFilename, std::move(E));158 return Error::success();159}160 161} // end namespace wasm162} // end namespace objcopy163} // end namespace llvm164