[Object] Add tapi files to object

Summary:
The intention for this is to allow reading and printing symbols out from
llvm-nm. Tapi file, and Tapi universal follow a similiar format to
their respective MachO Object format.

The tests are dependent on llvm-nm processing tbd files which is why its in D66160

Reviewers: ributzka, steven_wu, lhames

Reviewed By: ributzka, lhames

Subscribers: mgorny, hiraditya, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66159

llvm-svn: 369600

1 files changed, 104 insertions, 0 deletions

diff --git a/llvm/lib/Object/TapiFile.cpp b/llvm/lib/Object/TapiFile.cpp
new file mode 100644
index 0000000..be7d762
--- /dev/null
+++ b/llvm/lib/Object/TapiFile.cpp
@@ -0,0 +1,104 @@
+//===- TapiFile.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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the Text-based Dynamcic Library Stub format.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Object/TapiFile.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Object/Error.h"
+#include "llvm/Support/MemoryBuffer.h"
+
+using namespace llvm;
+using namespace MachO;
+using namespace object;
+
+static constexpr StringLiteral ObjC1ClassNamePrefix = ".objc_class_name_";
+static constexpr StringLiteral ObjC2ClassNamePrefix = "_OBJC_CLASS_$_";
+static constexpr StringLiteral ObjC2MetaClassNamePrefix = "_OBJC_METACLASS_$_";
+static constexpr StringLiteral ObjC2EHTypePrefix = "_OBJC_EHTYPE_$_";
+static constexpr StringLiteral ObjC2IVarPrefix = "_OBJC_IVAR_$_";
+
+static uint32_t getFlags(const Symbol *Sym) {
+  uint32_t Flags = BasicSymbolRef::SF_Global;
+  if (Sym->isUndefined())
+    Flags |= BasicSymbolRef::SF_Undefined;
+  else
+    Flags |= BasicSymbolRef::SF_Exported;
+
+  if (Sym->isWeakDefined() || Sym->isWeakReferenced())
+    Flags |= BasicSymbolRef::SF_Weak;
+
+  return Flags;
+}
+
+TapiFile::TapiFile(MemoryBufferRef Source, const InterfaceFile &interface,
+                   Architecture Arch)
+    : SymbolicFile(ID_TapiFile, Source) {
+  for (const auto *Symbol : interface.symbols()) {
+    if (!Symbol->getArchitectures().has(Arch))
+      continue;
+
+    auto PlatformKind = interface.getPlatform();
+    switch (Symbol->getKind()) {
+    case SymbolKind::GlobalSymbol:
+      Symbols.emplace_back(StringRef(), Symbol->getName(), getFlags(Symbol));
+      break;
+    case SymbolKind::ObjectiveCClass:
+      if (PlatformKind == PlatformKind::macOS && Arch == AK_i386) {
+        Symbols.emplace_back(ObjC1ClassNamePrefix, Symbol->getName(),
+                             getFlags(Symbol));
+      } else {
+        Symbols.emplace_back(ObjC2ClassNamePrefix, Symbol->getName(),
+                             getFlags(Symbol));
+        Symbols.emplace_back(ObjC2MetaClassNamePrefix, Symbol->getName(),
+                             getFlags(Symbol));
+      }
+      break;
+    case SymbolKind::ObjectiveCClassEHType:
+      Symbols.emplace_back(ObjC2EHTypePrefix, Symbol->getName(),
+                           getFlags(Symbol));
+      break;
+    case SymbolKind::ObjectiveCInstanceVariable:
+      Symbols.emplace_back(ObjC2IVarPrefix, Symbol->getName(),
+                           getFlags(Symbol));
+      break;
+    }
+  }
+}
+
+TapiFile::~TapiFile() = default;
+
+void TapiFile::moveSymbolNext(DataRefImpl &DRI) const {
+  const auto *Sym = reinterpret_cast<const Symbol *>(DRI.p);
+  DRI.p = reinterpret_cast<uintptr_t>(++Sym);
+}
+
+Error TapiFile::printSymbolName(raw_ostream &OS, DataRefImpl DRI) const {
+  const auto *Sym = reinterpret_cast<const Symbol *>(DRI.p);
+  OS << Sym->Prefix << Sym->Name;
+  return Error::success();
+}
+
+uint32_t TapiFile::getSymbolFlags(DataRefImpl DRI) const {
+  const auto *Sym = reinterpret_cast<const Symbol *>(DRI.p);
+  return Sym->Flags;
+}
+
+basic_symbol_iterator TapiFile::symbol_begin() const {
+  DataRefImpl DRI;
+  DRI.p = reinterpret_cast<uintptr_t>(&*Symbols.begin());
+  return BasicSymbolRef{DRI, this};
+}
+
+basic_symbol_iterator TapiFile::symbol_end() const {
+  DataRefImpl DRI;
+  DRI.p = reinterpret_cast<uintptr_t>(&*Symbols.end());
+  return BasicSymbolRef{DRI, this};
+}