1 files changed, 233 insertions, 0 deletions
diff --git a/llvm/lib/Support/ELFAttributeParser.cpp b/llvm/lib/Support/ELFAttributeParser.cpp
new file mode 100644
index 0000000000000..df955cdf5d30a
--- /dev/null
+++ b/llvm/lib/Support/ELFAttributeParser.cpp
@@ -0,0 +1,233 @@
+//===--- ELFAttributeParser.cpp - ELF Attribute Parser --------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/ELFAttributeParser.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/ScopedPrinter.h"
+
+using namespace llvm;
+using namespace llvm::ELFAttrs;
+
+static const EnumEntry<unsigned> tagNames[] = {
+    {"Tag_File", ELFAttrs::File},
+    {"Tag_Section", ELFAttrs::Section},
+    {"Tag_Symbol", ELFAttrs::Symbol},
+};
+
+Error ELFAttributeParser::parseStringAttribute(const char *name, unsigned tag,
+                                               ArrayRef<const char *> strings) {
+  uint64_t value = de.getULEB128(cursor);
+  if (value >= strings.size()) {
+    printAttribute(tag, value, "");
+    return createStringError(errc::invalid_argument,
+                             "unknown " + Twine(name) +
+                                 " value: " + Twine(value));
+  }
+  printAttribute(tag, value, strings[value]);
+  return Error::success();
+}
+
+Error ELFAttributeParser::integerAttribute(unsigned tag) {
+  StringRef tagName =
+      ELFAttrs::attrTypeAsString(tag, tagToStringMap, /*hasTagPrefix=*/false);
+  uint64_t value = de.getULEB128(cursor);
+  attributes.insert(std::make_pair(tag, value));
+
+  if (sw) {
+    DictScope scope(*sw, "Attribute");
+    sw->printNumber("Tag", tag);
+    if (!tagName.empty())
+      sw->printString("TagName", tagName);
+    sw->printNumber("Value", value);
+  }
+  return Error::success();
+}
+
+Error ELFAttributeParser::stringAttribute(unsigned tag) {
+  StringRef tagName =
+      ELFAttrs::attrTypeAsString(tag, tagToStringMap, /*hasTagPrefix=*/false);
+  StringRef desc = de.getCStrRef(cursor);
+  attributesStr.insert(std::make_pair(tag, desc));
+
+  if (sw) {
+    DictScope scope(*sw, "Attribute");
+    sw->printNumber("Tag", tag);
+    if (!tagName.empty())
+      sw->printString("TagName", tagName);
+    sw->printString("Value", desc);
+  }
+  return Error::success();
+}
+
+void ELFAttributeParser::printAttribute(unsigned tag, unsigned value,
+                                        StringRef valueDesc) {
+  attributes.insert(std::make_pair(tag, value));
+
+  if (sw) {
+    StringRef tagName = ELFAttrs::attrTypeAsString(tag, tagToStringMap,
+                                                   /*hasTagPrefix=*/false);
+    DictScope as(*sw, "Attribute");
+    sw->printNumber("Tag", tag);
+    sw->printNumber("Value", value);
+    if (!tagName.empty())
+      sw->printString("TagName", tagName);
+    if (!valueDesc.empty())
+      sw->printString("Description", valueDesc);
+  }
+}
+
+void ELFAttributeParser::parseIndexList(SmallVectorImpl<uint8_t> &indexList) {
+  for (;;) {
+    uint64_t value = de.getULEB128(cursor);
+    if (!cursor || !value)
+      break;
+    indexList.push_back(value);
+  }
+}
+
+Error ELFAttributeParser::parseAttributeList(uint32_t length) {
+  uint64_t pos;
+  uint64_t end = cursor.tell() + length;
+  while ((pos = cursor.tell()) < end) {
+    uint64_t tag = de.getULEB128(cursor);
+    bool handled;
+    if (Error e = handler(tag, handled))
+      return e;
+
+    if (!handled) {
+      if (tag < 32) {
+        return createStringError(errc::invalid_argument,
+                                 "invalid tag 0x" + Twine::utohexstr(tag) +
+                                     " at offset 0x" + Twine::utohexstr(pos));
+      }
+
+      if (tag % 2 == 0) {
+        if (Error e = integerAttribute(tag))
+          return e;
+      } else {
+        if (Error e = stringAttribute(tag))
+          return e;
+      }
+    }
+  }
+  return Error::success();
+}
+
+Error ELFAttributeParser::parseSubsection(uint32_t length) {
+  uint64_t end = cursor.tell() - sizeof(length) + length;
+  StringRef vendorName = de.getCStrRef(cursor);
+  if (sw) {
+    sw->printNumber("SectionLength", length);
+    sw->printString("Vendor", vendorName);
+  }
+
+  // Ignore unrecognized vendor-name.
+  if (vendorName.lower() != vendor)
+    return createStringError(errc::invalid_argument,
+                             "unrecognized vendor-name: " + vendorName);
+
+  while (cursor.tell() < end) {
+    /// Tag_File | Tag_Section | Tag_Symbol   uleb128:byte-size
+    uint8_t tag = de.getU8(cursor);
+    uint32_t size = de.getU32(cursor);
+    if (!cursor)
+      return cursor.takeError();
+
+    if (sw) {
+      sw->printEnum("Tag", tag, makeArrayRef(tagNames));
+      sw->printNumber("Size", size);
+    }
+    if (size < 5)
+      return createStringError(errc::invalid_argument,
+                               "invalid attribute size " + Twine(size) +
+                                   " at offset 0x" +
+                                   Twine::utohexstr(cursor.tell() - 5));
+
+    StringRef scopeName, indexName;
+    SmallVector<uint8_t, 8> indicies;
+    switch (tag) {
+    case ELFAttrs::File:
+      scopeName = "FileAttributes";
+      break;
+    case ELFAttrs::Section:
+      scopeName = "SectionAttributes";
+      indexName = "Sections";
+      parseIndexList(indicies);
+      break;
+    case ELFAttrs::Symbol:
+      scopeName = "SymbolAttributes";
+      indexName = "Symbols";
+      parseIndexList(indicies);
+      break;
+    default:
+      return createStringError(errc::invalid_argument,
+                               "unrecognized tag 0x" + Twine::utohexstr(tag) +
+                                   " at offset 0x" +
+                                   Twine::utohexstr(cursor.tell() - 5));
+    }
+
+    if (sw) {
+      DictScope scope(*sw, scopeName);
+      if (!indicies.empty())
+        sw->printList(indexName, indicies);
+      if (Error e = parseAttributeList(size - 5))
+        return e;
+    } else if (Error e = parseAttributeList(size - 5))
+      return e;
+  }
+  return Error::success();
+}
+
+Error ELFAttributeParser::parse(ArrayRef<uint8_t> section,
+                                support::endianness endian) {
+  unsigned sectionNumber = 0;
+  de = DataExtractor(section, endian == support::little, 0);
+
+  // For early returns, we have more specific errors, consume the Error in
+  // cursor.
+  struct ClearCursorError {
+    DataExtractor::Cursor &cursor;
+    ~ClearCursorError() { consumeError(cursor.takeError()); }
+  } clear{cursor};
+
+  // Unrecognized format-version.
+  uint8_t formatVersion = de.getU8(cursor);
+  if (formatVersion != 'A')
+    return createStringError(errc::invalid_argument,
+                             "unrecognized format-version: 0x" +
+                                 utohexstr(formatVersion));
+
+  while (!de.eof(cursor)) {
+    uint32_t sectionLength = de.getU32(cursor);
+    if (!cursor)
+      return cursor.takeError();
+
+    if (sw) {
+      sw->startLine() << "Section " << ++sectionNumber << " {\n";
+      sw->indent();
+    }
+
+    if (sectionLength < 4 || cursor.tell() - 4 + sectionLength > section.size())
+      return createStringError(errc::invalid_argument,
+                               "invalid section length " +
+                                   Twine(sectionLength) + " at offset 0x" +
+                                   utohexstr(cursor.tell() - 4));
+
+    if (Error e = parseSubsection(sectionLength))
+      return e;
+    if (sw) {
+      sw->unindent();
+      sw->startLine() << "}\n";
+    }
+  }
+
+  return cursor.takeError();
+}