[lld][WebAssembly] Replace config-> with ctx.arg.

Change the global variable reference to a member access of another
variable `ctx`. In the future, we may pass through `ctx` to functions to
eliminate global variables.

Pull Request: #119835

Author: MaskRay

lld/wasm/Config.h

@@ -126,17 +126,9 @@ struct Config {
   llvm::SmallVector<uint8_t, 0> buildIdVector;
 };
 
-struct ConfigWrapper {
-  Config c;
-  Config *operator->() { return &c; }
-};
-
-// The only instance of Configuration struct.
-extern ConfigWrapper config;
-
 // The Ctx object hold all other (non-configuration) global state.
 struct Ctx {
-  Config &arg;
+  Config arg;
 
   llvm::SmallVector<ObjFile *, 0> objectFiles;
   llvm::SmallVector<StubFile *, 0> stubFiles;

lld/wasm/Driver.cpp

@@ -67,7 +67,7 @@ uint32_t InputChunk::getSize() const {
     return ms->builder.getSize();
 
   if (const auto *f = dyn_cast<InputFunction>(this)) {
-    if (config->compressRelocations && f->file) {
+    if (ctx.arg.compressRelocations && f->file) {
       return f->getCompressedSize();
     }
   }
@@ -84,7 +84,7 @@ uint32_t InputChunk::getInputSize() const {
 // Copy this input chunk to an mmap'ed output file and apply relocations.
 void InputChunk::writeTo(uint8_t *buf) const {
   if (const auto *f = dyn_cast<InputFunction>(this)) {
-    if (file && config->compressRelocations)
+    if (file && ctx.arg.compressRelocations)
       return f->writeCompressed(buf);
   } else if (const auto *ms = dyn_cast<SyntheticMergedChunk>(this)) {
     ms->builder.write(buf + outSecOff);
@@ -269,7 +269,7 @@ static unsigned getRelocWidth(const WasmRelocation &rel, uint64_t value) {
 // This function only computes the final output size.  It must be called
 // before getSize() is used to calculate of layout of the code section.
 void InputFunction::calculateSize() {
-  if (!file || !config->compressRelocations)
+  if (!file || !ctx.arg.compressRelocations)
     return;
 
   LLVM_DEBUG(dbgs() << "calculateSize: " << name << "\n");
@@ -365,7 +365,7 @@ bool InputChunk::generateRelocationCode(raw_ostream &os) const {
   LLVM_DEBUG(dbgs() << "generating runtime relocations: " << name
                     << " count=" << relocations.size() << "\n");
 
-  bool is64 = config->is64.value_or(false);
+  bool is64 = ctx.arg.is64.value_or(false);
   bool generated = false;
   unsigned opcode_ptr_const = is64 ? WASM_OPCODE_I64_CONST
                                    : WASM_OPCODE_I32_CONST;

lld/wasm/InputChunks.cpp

@@ -112,7 +112,7 @@ class InputChunk {
   InputChunk(ObjFile *f, Kind k, StringRef name, uint32_t alignment = 0,
              uint32_t flags = 0)
       : name(name), file(f), alignment(alignment), flags(flags), sectionKind(k),
-        live(!config->gcSections), discarded(false) {}
+        live(!ctx.arg.gcSections), discarded(false) {}
   ArrayRef<uint8_t> data() const { return rawData; }
   uint64_t getTombstone() const;
 
@@ -156,7 +156,7 @@ class SyntheticMergedChunk;
 // be found by looking at the next one).
 struct SectionPiece {
   SectionPiece(size_t off, uint32_t hash, bool live)
-      : inputOff(off), live(live || !config->gcSections), hash(hash >> 1) {}
+      : inputOff(off), live(live || !ctx.arg.gcSections), hash(hash >> 1) {}
 
   uint32_t inputOff;
   uint32_t live : 1;

lld/wasm/InputChunks.h

@@ -24,7 +24,7 @@ namespace wasm {
 class InputElement {
 protected:
   InputElement(StringRef name, ObjFile *f)
-      : file(f), live(!config->gcSections), name(name) {}
+      : file(f), live(!ctx.arg.gcSections), name(name) {}
 
 public:
   StringRef getName() const { return name; }
@@ -65,7 +65,7 @@ class InputGlobal : public InputElement {
   const WasmInitExpr &getInitExpr() const { return initExpr; }
 
   void setPointerValue(uint64_t value) {
-    initExpr = intConst(value, config->is64.value_or(false));
+    initExpr = intConst(value, ctx.arg.is64.value_or(false));
   }
 
 private:

lld/wasm/InputElement.h

@@ -47,18 +47,18 @@ std::string toString(const wasm::InputFile *file) {
 namespace wasm {
 
 std::string replaceThinLTOSuffix(StringRef path) {
-  auto [suffix, repl] = config->thinLTOObjectSuffixReplace;
+  auto [suffix, repl] = ctx.arg.thinLTOObjectSuffixReplace;
   if (path.consume_back(suffix))
     return (path + repl).str();
   return std::string(path);
 }
 
 void InputFile::checkArch(Triple::ArchType arch) const {
   bool is64 = arch == Triple::wasm64;
-  if (is64 && !config->is64) {
+  if (is64 && !ctx.arg.is64) {
     fatal(toString(this) +
           ": must specify -mwasm64 to process wasm64 object files");
-  } else if (config->is64.value_or(false) != is64) {
+  } else if (ctx.arg.is64.value_or(false) != is64) {
     fatal(toString(this) +
           ": wasm32 object file can't be linked in wasm64 mode");
   }
@@ -169,7 +169,7 @@ uint64_t ObjFile::calcNewValue(const WasmRelocation &reloc, uint64_t tombstone,
     uint32_t index = getFunctionSymbol(reloc.Index)->getTableIndex();
     if (reloc.Type == R_WASM_TABLE_INDEX_REL_SLEB ||
         reloc.Type == R_WASM_TABLE_INDEX_REL_SLEB64)
-      index -= config->tableBase;
+      index -= ctx.arg.tableBase;
     return index;
   }
   case R_WASM_MEMORY_ADDR_LEB:
@@ -360,7 +360,7 @@ void ObjFile::addLegacyIndirectFunctionTableIfNeeded(
 }
 
 static bool shouldMerge(const WasmSection &sec) {
-  if (config->optimize == 0)
+  if (ctx.arg.optimize == 0)
     return false;
   // Sadly we don't have section attributes yet for custom sections, so we
   // currently go by the name alone.
@@ -383,7 +383,7 @@ static bool shouldMerge(const WasmSegment &seg) {
   // On a regular link we don't merge sections if -O0 (default is -O1). This
   // sometimes makes the linker significantly faster, although the output will
   // be bigger.
-  if (config->optimize == 0)
+  if (ctx.arg.optimize == 0)
     return false;
 
   // A mergeable section with size 0 is useless because they don't have
@@ -845,7 +845,7 @@ BitcodeFile::BitcodeFile(MemoryBufferRef m, StringRef archiveName,
   this->archiveName = std::string(archiveName);
 
   std::string path = mb.getBufferIdentifier().str();
-  if (config->thinLTOIndexOnly)
+  if (ctx.arg.thinLTOIndexOnly)
     path = replaceThinLTOSuffix(mb.getBufferIdentifier());
 
   // ThinLTO assumes that all MemoryBufferRefs given to it have a unique

lld/wasm/InputFiles.cpp

@@ -73,7 +73,7 @@ class InputFile {
 
 protected:
   InputFile(Kind k, MemoryBufferRef m)
-      : mb(m), fileKind(k), live(!config->gcSections) {}
+      : mb(m), fileKind(k), live(!ctx.arg.gcSections) {}
 
   void checkArch(llvm::Triple::ArchType arch) const;
 

lld/wasm/InputFiles.h

@@ -44,8 +44,8 @@ using namespace lld::wasm;
 using namespace lld;
 
 static std::string getThinLTOOutputFile(StringRef modulePath) {
-  return lto::getThinLTOOutputFile(modulePath, config->thinLTOPrefixReplaceOld,
-                                   config->thinLTOPrefixReplaceNew);
+  return lto::getThinLTOOutputFile(modulePath, ctx.arg.thinLTOPrefixReplaceOld,
+                                   ctx.arg.thinLTOPrefixReplaceNew);
 }
 
 static lto::Config createConfig() {
@@ -56,23 +56,23 @@ static lto::Config createConfig() {
   c.Options.FunctionSections = true;
   c.Options.DataSections = true;
 
-  c.DisableVerify = config->disableVerify;
+  c.DisableVerify = ctx.arg.disableVerify;
   c.DiagHandler = diagnosticHandler;
-  c.OptLevel = config->ltoo;
+  c.OptLevel = ctx.arg.ltoo;
   c.MAttrs = getMAttrs();
-  c.CGOptLevel = config->ltoCgo;
-  c.DebugPassManager = config->ltoDebugPassManager;
-  c.AlwaysEmitRegularLTOObj = !config->ltoObjPath.empty();
+  c.CGOptLevel = ctx.arg.ltoCgo;
+  c.DebugPassManager = ctx.arg.ltoDebugPassManager;
+  c.AlwaysEmitRegularLTOObj = !ctx.arg.ltoObjPath.empty();
 
-  if (config->relocatable)
+  if (ctx.arg.relocatable)
     c.RelocModel = std::nullopt;
   else if (ctx.isPic)
     c.RelocModel = Reloc::PIC_;
   else
     c.RelocModel = Reloc::Static;
 
-  if (config->saveTemps)
-    checkError(c.addSaveTemps(config->outputFile.str() + ".",
+  if (ctx.arg.saveTemps)
+    checkError(c.addSaveTemps(ctx.arg.outputFile.str() + ".",
                               /*UseInputModulePath*/ true));
   return c;
 }
@@ -81,27 +81,27 @@ namespace lld::wasm {
 
 BitcodeCompiler::BitcodeCompiler() {
   // Initialize indexFile.
-  if (!config->thinLTOIndexOnlyArg.empty())
-    indexFile = openFile(config->thinLTOIndexOnlyArg);
+  if (!ctx.arg.thinLTOIndexOnlyArg.empty())
+    indexFile = openFile(ctx.arg.thinLTOIndexOnlyArg);
 
   // Initialize ltoObj.
   lto::ThinBackend backend;
   auto onIndexWrite = [&](StringRef s) { thinIndices.erase(s); };
-  if (config->thinLTOIndexOnly) {
+  if (ctx.arg.thinLTOIndexOnly) {
     backend = lto::createWriteIndexesThinBackend(
-        llvm::hardware_concurrency(config->thinLTOJobs),
-        std::string(config->thinLTOPrefixReplaceOld),
-        std::string(config->thinLTOPrefixReplaceNew),
-        std::string(config->thinLTOPrefixReplaceNativeObject),
-        config->thinLTOEmitImportsFiles, indexFile.get(), onIndexWrite);
+        llvm::hardware_concurrency(ctx.arg.thinLTOJobs),
+        std::string(ctx.arg.thinLTOPrefixReplaceOld),
+        std::string(ctx.arg.thinLTOPrefixReplaceNew),
+        std::string(ctx.arg.thinLTOPrefixReplaceNativeObject),
+        ctx.arg.thinLTOEmitImportsFiles, indexFile.get(), onIndexWrite);
   } else {
     backend = lto::createInProcessThinBackend(
-        llvm::heavyweight_hardware_concurrency(config->thinLTOJobs),
-        onIndexWrite, config->thinLTOEmitIndexFiles,
-        config->thinLTOEmitImportsFiles);
+        llvm::heavyweight_hardware_concurrency(ctx.arg.thinLTOJobs),
+        onIndexWrite, ctx.arg.thinLTOEmitIndexFiles,
+        ctx.arg.thinLTOEmitImportsFiles);
   }
   ltoObj = std::make_unique<lto::LTO>(createConfig(), backend,
-                                      config->ltoPartitions);
+                                      ctx.arg.ltoPartitions);
 }
 
 BitcodeCompiler::~BitcodeCompiler() = default;
@@ -123,7 +123,7 @@ void BitcodeCompiler::add(BitcodeFile &f) {
   ArrayRef<Symbol *> syms = f.getSymbols();
   std::vector<lto::SymbolResolution> resols(syms.size());
 
-  if (config->thinLTOEmitIndexFiles) {
+  if (ctx.arg.thinLTOEmitIndexFiles) {
     thinIndices.insert(obj.getName());
   }
 
@@ -139,7 +139,7 @@ void BitcodeCompiler::add(BitcodeFile &f) {
     // Once IRObjectFile is fixed to report only one symbol this hack can
     // be removed.
     r.Prevailing = !objSym.isUndefined() && sym->getFile() == &f;
-    r.VisibleToRegularObj = config->relocatable || sym->isUsedInRegularObj ||
+    r.VisibleToRegularObj = ctx.arg.relocatable || sym->isUsedInRegularObj ||
                             sym->isNoStrip() ||
                             (r.Prevailing && sym->isExported());
     if (r.Prevailing)
@@ -175,7 +175,7 @@ static void thinLTOCreateEmptyIndexFiles() {
     ModuleSummaryIndex m(/*HaveGVs*/ false);
     m.setSkipModuleByDistributedBackend();
     writeIndexToFile(m, *os);
-    if (config->thinLTOEmitImportsFiles)
+    if (ctx.arg.thinLTOEmitImportsFiles)
       openFile(path + ".imports");
   }
 }
@@ -191,8 +191,8 @@ std::vector<StringRef> BitcodeCompiler::compile() {
   // to cache native object files for ThinLTO incremental builds. If a path was
   // specified, configure LTO to use it as the cache directory.
   FileCache cache;
-  if (!config->thinLTOCacheDir.empty())
-    cache = check(localCache("ThinLTO", "Thin", config->thinLTOCacheDir,
+  if (!ctx.arg.thinLTOCacheDir.empty())
+    cache = check(localCache("ThinLTO", "Thin", ctx.arg.thinLTOCacheDir,
                              [&](size_t task, const Twine &moduleName,
                                  std::unique_ptr<MemoryBuffer> mb) {
                                files[task] = std::move(mb);
@@ -210,16 +210,16 @@ std::vector<StringRef> BitcodeCompiler::compile() {
   for (StringRef s : thinIndices) {
     std::string path(s);
     openFile(path + ".thinlto.bc");
-    if (config->thinLTOEmitImportsFiles)
+    if (ctx.arg.thinLTOEmitImportsFiles)
       openFile(path + ".imports");
   }
 
-  if (config->thinLTOEmitIndexFiles)
+  if (ctx.arg.thinLTOEmitIndexFiles)
     thinLTOCreateEmptyIndexFiles();
 
-  if (config->thinLTOIndexOnly) {
-    if (!config->ltoObjPath.empty())
-      saveBuffer(buf[0].second, config->ltoObjPath);
+  if (ctx.arg.thinLTOIndexOnly) {
+    if (!ctx.arg.ltoObjPath.empty())
+      saveBuffer(buf[0].second, ctx.arg.ltoObjPath);
 
     // ThinLTO with index only option is required to generate only the index
     // files. After that, we exit from linker and ThinLTO backend runs in a
@@ -229,8 +229,8 @@ std::vector<StringRef> BitcodeCompiler::compile() {
     return {};
   }
 
-  if (!config->thinLTOCacheDir.empty())
-    pruneCache(config->thinLTOCacheDir, config->thinLTOCachePolicy, files);
+  if (!ctx.arg.thinLTOCacheDir.empty())
+    pruneCache(ctx.arg.thinLTOCacheDir, ctx.arg.thinLTOCachePolicy, files);
 
   std::vector<StringRef> ret;
   for (unsigned i = 0; i != maxTasks; ++i) {
@@ -239,7 +239,7 @@ std::vector<StringRef> BitcodeCompiler::compile() {
     if (objBuf.empty())
       continue;
     ret.emplace_back(objBuf.data(), objBuf.size());
-    if (!config->saveTemps)
+    if (!ctx.arg.saveTemps)
       continue;
 
     // If the input bitcode file is path/to/x.o and -o specifies a.out, the
@@ -248,7 +248,7 @@ std::vector<StringRef> BitcodeCompiler::compile() {
     StringRef ltoObjName;
     if (bitcodeFilePath == "ld-temp.o") {
       ltoObjName =
-          saver().save(Twine(config->outputFile) + ".lto" +
+          saver().save(Twine(ctx.arg.outputFile) + ".lto" +
                        (i == 0 ? Twine("") : Twine('.') + Twine(i)) + ".o");
     } else {
       StringRef directory = sys::path::parent_path(bitcodeFilePath);
@@ -258,7 +258,7 @@ std::vector<StringRef> BitcodeCompiler::compile() {
       StringRef baseName = bitcodeFilePath.ends_with(")")
                                ? sys::path::filename(bitcodeFilePath)
                                : sys::path::stem(bitcodeFilePath);
-      StringRef outputFileBaseName = sys::path::filename(config->outputFile);
+      StringRef outputFileBaseName = sys::path::filename(ctx.arg.outputFile);
       SmallString<256> path;
       sys::path::append(path, directory,
                         outputFileBaseName + ".lto." + baseName + ".o");
@@ -268,10 +268,10 @@ std::vector<StringRef> BitcodeCompiler::compile() {
     saveBuffer(objBuf, ltoObjName);
   }
 
-  if (!config->ltoObjPath.empty()) {
-    saveBuffer(buf[0].second, config->ltoObjPath);
+  if (!ctx.arg.ltoObjPath.empty()) {
+    saveBuffer(buf[0].second, ctx.arg.ltoObjPath);
     for (unsigned i = 1; i != maxTasks; ++i)
-      saveBuffer(buf[i].second, config->ltoObjPath + Twine(i));
+      saveBuffer(buf[i].second, ctx.arg.ltoObjPath + Twine(i));
   }
 
   for (std::unique_ptr<MemoryBuffer> &file : files)

lld/wasm/LTO.cpp

@@ -103,14 +103,14 @@ getSymbolStrings(ArrayRef<Symbol *> syms) {
 }
 
 void lld::wasm::writeMapFile(ArrayRef<OutputSection *> outputSections) {
-  if (config->mapFile.empty())
+  if (ctx.arg.mapFile.empty())
     return;
 
   // Open a map file for writing.
   std::error_code ec;
-  raw_fd_ostream os(config->mapFile, ec, sys::fs::OF_None);
+  raw_fd_ostream os(ctx.arg.mapFile, ec, sys::fs::OF_None);
   if (ec) {
-    error("cannot open " + config->mapFile + ": " + ec.message());
+    error("cannot open " + ctx.arg.mapFile + ": " + ec.message());
     return;
   }