folly: symbolizer: add minimal folly-addr2line tool -- intented for validation...

folly: symbolizer: add minimal folly-addr2line tool -- intented for validation tests/debugging, not as a full-featured replacement for addr2line

Reviewed By: Orvid

Differential Revision: D25991335

fbshipit-source-id: fcdc1b1cdeab7623c67b69ce2f80b062c0935436

CMakeLists.txt

@@ -165,6 +165,7 @@ list(REMOVE_ITEM files
   ${FOLLY_DIR}/python/fibers.cpp
   ${FOLLY_DIR}/python/GILAwareManualExecutor.cpp
   ${FOLLY_DIR}/cybld/folly/executor.cpp
+  ${FOLLY_DIR}/experimental/symbolizer/Addr2Line.cpp
 )
 list(REMOVE_ITEM hfiles
   ${FOLLY_DIR}/python/fibers.h

folly/experimental/symbolizer/Addr2Line.cpp

+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Minimal addr2line using folly::symbolizer. Used for tests.
+ *
+ *    folly-addr2line -e objectfile --demangle <addr1> [<addr2> ...]
+ */
+
+#include <algorithm>
+#include <array>
+#include <iostream>
+
+#include <folly/Range.h>
+#include <folly/experimental/symbolizer/Dwarf.h>
+#include <folly/experimental/symbolizer/Elf.h>
+#include <folly/experimental/symbolizer/SymbolizedFrame.h>
+#include <folly/experimental/symbolizer/Symbolizer.h>
+#include <folly/init/Init.h>
+#include <folly/portability/GFlags.h>
+
+#if FOLLY_HAVE_DWARF && FOLLY_HAVE_ELF
+
+DEFINE_string(e, "", "Path to ELF object file (.so, binary)");
+DEFINE_bool(demangle, false, "Degmangle symbols");
+
+using namespace folly::symbolizer;
+
+void addr2line(std::shared_ptr<ElfFile> elfFile, uintptr_t address) {
+  if (elfFile->getSectionContainingAddress(address) == nullptr) {
+    std::cout << "0x" << std::hex << address << std::dec << "\n??\n??:0\n";
+    return;
+  }
+
+  auto sym = elfFile->getDefinitionByAddress(address);
+  if (sym.first == nullptr) {
+    std::cout << "0x" << std::hex << address << std::dec << "\n??\n??:0\n";
+    return;
+  }
+
+  std::array<SymbolizedFrame, 100> frames;
+  frames[0].found = true;
+  frames[0].addr = address;
+  frames[0].file = elfFile;
+  frames[0].name = elfFile->getSymbolName(sym);
+
+  Dwarf(elfFile.get())
+      .findAddress(
+          address,
+          LocationInfoMode::FULL_WITH_INLINE,
+          frames[0].location,
+          /* extraInlineFrames */ folly::range(frames).subpiece(1));
+
+  size_t n = 0;
+  while (frames[n].found) {
+    n++;
+  }
+
+  // Inlined frames [1,n) are filled in deepest call first order,
+  // but frames[0] is used for the non-inlined caller.
+  // Move frames[0] to the end so the entire array is ordered.
+  std::rotate(&frames[0], &frames[1], &frames[0] + n);
+
+  CHECK_NE(n, 0);
+  std::cout << "0x" << std::hex << address << std::dec << '\n';
+  for (size_t i = 0; i < n; i++) {
+    const auto& f = frames[i];
+    std::cout << (f.name ? (FLAGS_demangle ? folly::demangle(f.name) : f.name)
+                         : "??")
+              << '\n';
+    auto path = f.location.file.toString();
+    path = path.empty() ? "??" : path;
+    std::cout << path << ":" << f.location.line << '\n';
+  }
+}
+
+int main(int argc, char* argv[]) {
+  folly::Init init(&argc, &argv);
+  auto elfFile = std::make_shared<ElfFile>(FLAGS_e.c_str());
+
+  for (int i = 1; i < argc; i++) {
+    addr2line(elfFile, folly::to<uintptr_t>(argv[i]));
+  }
+  return 0;
+}
+
+#else // FOLLY_HAVE_DWARF && FOLLY_HAVE_ELF
+
+int main(int argc, char* argv[]) {
+  return 1;
+}
+
+#endif // FOLLY_HAVE_DWARF && FOLLY_HAVE_ELF