[llvm-tapi] initial commit, supports ELF text stubs

http://lists.llvm.org/pipermail/llvm-dev/2018-September/126472.html

TextAPI is a library and accompanying tool that allows conversion between binary shared object stubs and textual counterparts. The motivations and uses cases for this are explained thoroughly in the llvm-dev proposal [1]. This initial commit proposes a potential structure for the TAPI library, also including support for reading/writing text-based ELF stubs (.tbe) in addition to preliminary support for reading binary ELF files. The goal for this patch is to ensure the project architecture appropriately welcomes integration of Mach-O stubbing from Apple's TAPI [2].

Added:

 - TextAPI library
 - .tbe read support
 - .tbe write (to raw_ostream) support

[1] http://lists.llvm.org/pipermail/llvm-dev/2018-September/126472.html
[2] https://github.com/ributzka/tapi

Differential Revision: https://reviews.llvm.org/D53051

llvm-svn: 348170

1 files changed, 216 insertions, 0 deletions

diff --git a/llvm/unittests/TextAPI/ELFYAMLTest.cpp b/llvm/unittests/TextAPI/ELFYAMLTest.cpp
new file mode 100644
index 00000000000..4616531de98
--- /dev/null
+++ b/llvm/unittests/TextAPI/ELFYAMLTest.cpp
@@ -0,0 +1,216 @@
+//===- llvm/unittests/TextAPI/YAMLTest.cpp --------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===-----------------------------------------------------------------------===/
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/TextAPI/ELF/ELFStub.h"
+#include "llvm/TextAPI/ELF/TBEHandler.h"
+#include "llvm/Support/Error.h"
+#include "gtest/gtest.h"
+#include <string>
+
+using namespace llvm;
+using namespace llvm::ELF;
+using namespace llvm::elfabi;
+
+std::unique_ptr<ELFStub> readFromBuffer(const char Data[]) {
+  TBEHandler Handler;
+
+  StringRef Buf(Data);
+
+  std::unique_ptr<ELFStub> Stub = Handler.readFile(Buf);
+  EXPECT_NE(Stub.get(), nullptr);
+  return Stub;
+}
+
+void compareByLine(StringRef LHS, StringRef RHS) {
+  StringRef Line1;
+  StringRef Line2;
+  while (LHS.size() > 0 && RHS.size() > 0) {
+    std::tie(Line1, LHS) = LHS.split('\n');
+    std::tie(Line2, RHS) = RHS.split('\n');
+    // Comparing StringRef objects works, but has messy output when not equal.
+    // Using STREQ on StringRef.data() doesn't work since these substrings are
+    // not null terminated.
+    // This is inefficient, but forces null terminated strings that can be
+    // cleanly compared.
+    EXPECT_STREQ(Line1.str().data(), Line2.str().data());
+  }
+}
+
+TEST(ElfYamlTextAPI, YAMLReadableTBE) {
+  const char Data[] = "--- !tapi-tbe\n"
+                      "TbeVersion: 1.0\n"
+                      "SoName: test.so\n"
+                      "Arch: x86_64\n"
+                      "NeededLibs: [libc.so, libfoo.so, libbar.so]\n"
+                      "Symbols:\n"
+                      "  foo: { Type: Func, Undefined: true }\n"
+                      "...\n";
+  StringRef Buf = StringRef(Data);
+  TBEHandler Handler;
+  std::unique_ptr<ELFStub> Stub = Handler.readFile(Buf);
+  EXPECT_NE(Stub.get(), nullptr);
+  EXPECT_EQ(Stub->Arch, (uint16_t)llvm::ELF::EM_X86_64);
+  EXPECT_STREQ(Stub->SoName.c_str(), "test.so");
+  EXPECT_EQ(Stub->NeededLibs.size(), 3u);
+  EXPECT_STREQ(Stub->NeededLibs[0].c_str(), "libc.so");
+  EXPECT_STREQ(Stub->NeededLibs[1].c_str(), "libfoo.so");
+  EXPECT_STREQ(Stub->NeededLibs[2].c_str(), "libbar.so");
+}
+
+TEST(ElfYamlTextAPI, YAMLReadsTBESymbols) {
+  const char Data[] = "--- !tapi-tbe\n"
+                      "TbeVersion: 1.0\n"
+                      "SoName: test.so\n"
+                      "Arch: x86_64\n"
+                      "Symbols:\n"
+                      "  bar: { Type: Object, Size: 42 }\n"
+                      "  baz: { Type: TLS, Size: 3 }\n"
+                      "  foo: { Type: Func, Warning: \"Deprecated!\" }\n"
+                      "  nor: { Type: NoType, Undefined: true }\n"
+                      "  not: { Type: File, Undefined: true, Size: 111, "
+                      "Warning: \'All fields populated!\' }\n"
+                      "...\n";
+  std::unique_ptr<ELFStub> Stub = readFromBuffer(Data);
+  EXPECT_EQ(Stub->Symbols.size(), 5u);
+
+  auto Iterator = Stub->Symbols.begin();
+  ELFSymbol const &SymBar = *Iterator++;
+  EXPECT_STREQ(SymBar.Name.c_str(), "bar");
+  EXPECT_EQ(SymBar.Size, 42u);
+  EXPECT_EQ(SymBar.Type, ELFSymbolType::Object);
+  EXPECT_FALSE(SymBar.Undefined);
+  EXPECT_FALSE(SymBar.Warning.hasValue());
+
+  ELFSymbol const &SymBaz = *Iterator++;
+  EXPECT_STREQ(SymBaz.Name.c_str(), "baz");
+  EXPECT_EQ(SymBaz.Size, 3u);
+  EXPECT_EQ(SymBaz.Type, ELFSymbolType::TLS);
+  EXPECT_FALSE(SymBaz.Undefined);
+  EXPECT_FALSE(SymBaz.Warning.hasValue());
+
+  ELFSymbol const &SymFoo = *Iterator++;
+  EXPECT_STREQ(SymFoo.Name.c_str(), "foo");
+  EXPECT_EQ(SymFoo.Size, 0u);
+  EXPECT_EQ(SymFoo.Type, ELFSymbolType::Func);
+  EXPECT_FALSE(SymFoo.Undefined);
+  EXPECT_TRUE(SymFoo.Warning.hasValue());
+  EXPECT_STREQ(SymFoo.Warning->c_str(), "Deprecated!");
+
+  ELFSymbol const &SymNor = *Iterator++;
+  EXPECT_STREQ(SymNor.Name.c_str(), "nor");
+  EXPECT_EQ(SymNor.Size, 0u);
+  EXPECT_EQ(SymNor.Type, ELFSymbolType::NoType);
+  EXPECT_TRUE(SymNor.Undefined);
+  EXPECT_FALSE(SymNor.Warning.hasValue());
+
+  ELFSymbol const &SymNot = *Iterator++;
+  EXPECT_STREQ(SymNot.Name.c_str(), "not");
+  EXPECT_EQ(SymNot.Size, 111u);
+  EXPECT_EQ(SymNot.Type, ELFSymbolType::Unknown);
+  EXPECT_TRUE(SymNot.Undefined);
+  EXPECT_TRUE(SymNot.Warning.hasValue());
+  EXPECT_STREQ(SymNot.Warning->c_str(), "All fields populated!");
+}
+
+TEST(ElfYamlTextAPI, YAMLReadsNoTBESyms) {
+  const char Data[] = "--- !tapi-tbe\n"
+                      "TbeVersion: 1.0\n"
+                      "SoName: test.so\n"
+                      "Arch: x86_64\n"
+                      "Symbols: {}\n"
+                      "...\n";
+  std::unique_ptr<ELFStub> Stub = readFromBuffer(Data);
+  EXPECT_EQ(0u, Stub->Symbols.size());
+}
+
+TEST(ElfYamlTextAPI, YAMLUnreadableTBE) {
+  TBEHandler Handler;
+  // Can't read: wrong format/version.
+  const char Data[] = "--- !tapi-tbz\n"
+                      "TbeVersion: z.3\n"
+                      "SoName: test.so\n"
+                      "Arch: x86_64\n"
+                      "Symbols:\n"
+                      "  foo: { Type: Func, Undefined: true }\n";
+  StringRef Buf = StringRef(Data);
+  std::unique_ptr<ELFStub> Stub = Handler.readFile(Buf);
+  EXPECT_EQ(Stub.get(), nullptr);
+}
+
+TEST(ElfYamlTextAPI, YAMLWritesTBESymbols) {
+  const char Expected[] =
+      "--- !tapi-tbe\n"
+      "TbeVersion:      1.0\n"
+      "SoName:          test.so\n"
+      "Arch:            AArch64\n"
+      "Symbols:         \n"
+      "  foo:             { Type: NoType, Size: 99, Warning: Does nothing }\n"
+      "  nor:             { Type: Func, Undefined: true }\n"
+      "  not:             { Type: Unknown, Size: 12345678901234 }\n"
+      "...\n";
+  ELFStub Stub;
+  Stub.TbeVersion = VersionTuple(1, 0);
+  Stub.SoName = "test.so";
+  Stub.Arch = ELF::EM_AARCH64;
+
+  ELFSymbol SymFoo("foo");
+  SymFoo.Size = 99u;
+  SymFoo.Type = ELFSymbolType::NoType;
+  SymFoo.Undefined = false;
+  SymFoo.Warning = "Does nothing";
+
+  ELFSymbol SymNor("nor");
+  SymNor.Type = ELFSymbolType::Func;
+  SymNor.Undefined = true;
+
+  ELFSymbol SymNot("not");
+  SymNot.Size = 12345678901234u;
+  SymNot.Type = ELFSymbolType::Unknown;
+  SymNot.Undefined = false;
+
+  // Deliberately not in order to check that result is sorted.
+  Stub.Symbols.insert(SymNot);
+  Stub.Symbols.insert(SymFoo);
+  Stub.Symbols.insert(SymNor);
+
+  // Ensure move constructor works as expected.
+  ELFStub Moved = std::move(Stub);
+
+  std::string Result;
+  raw_string_ostream OS(Result);
+  TBEHandler Handler;
+  EXPECT_FALSE(Handler.writeFile(OS, Moved));
+  Result = OS.str();
+  compareByLine(Result.c_str(), Expected);
+}
+
+TEST(ElfYamlTextAPI, YAMLWritesNoTBESyms) {
+  const char Expected[] = "--- !tapi-tbe\n"
+                          "TbeVersion:      1.0\n"
+                          "SoName:          nosyms.so\n"
+                          "Arch:            x86_64\n"
+                          "NeededLibs:      [ libc.so, libfoo.so, libbar.so ]\n"
+                          "Symbols:         {}\n"
+                          "...\n";
+  ELFStub Stub;
+  Stub.TbeVersion = VersionTuple(1, 0);
+  Stub.SoName = "nosyms.so";
+  Stub.Arch = ELF::EM_X86_64;
+  Stub.NeededLibs.push_back("libc.so");
+  Stub.NeededLibs.push_back("libfoo.so");
+  Stub.NeededLibs.push_back("libbar.so");
+
+  std::string Result;
+  raw_string_ostream OS(Result);
+  TBEHandler Handler;
+  EXPECT_FALSE(Handler.writeFile(OS, Stub));
+  Result = OS.str();
+  compareByLine(Result.c_str(), Expected);
+}