GSYM: add encoding and decoding to FunctionInfo

This patch adds encoding and decoding of the FunctionInfo objects along with full error handling and tests. Full details of the FunctionInfo encoding format appear in the FunctionInfo.h header file.

Differential Revision: https://reviews.llvm.org/D67506

llvm-svn: 372135

1 files changed, 132 insertions, 4 deletions

diff --git a/llvm/lib/DebugInfo/GSYM/FunctionInfo.cpp b/llvm/lib/DebugInfo/GSYM/FunctionInfo.cpp
index 5b8b7ea44fb..dff867d66eb 100644
--- a/llvm/lib/DebugInfo/GSYM/FunctionInfo.cpp
+++ b/llvm/lib/DebugInfo/GSYM/FunctionInfo.cpp
@@ -1,19 +1,147 @@
 //===- FunctionInfo.cpp -----------------------------------------*- C++ -*-===//
 //
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
+// 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/DebugInfo/GSYM/FunctionInfo.h"
+#include "llvm/DebugInfo/GSYM/FileWriter.h"
+#include "llvm/DebugInfo/GSYM/LineTable.h"
+#include "llvm/DebugInfo/GSYM/InlineInfo.h"
+#include "llvm/Support/DataExtractor.h"
 
 using namespace llvm;
 using namespace gsym;
 
+/// FunctionInfo information type that is used to encode the optional data
+/// that is associated with a FunctionInfo object.
+enum InfoType : uint32_t {
+  EndOfList = 0u,
+  LineTableInfo = 1u,
+  InlineInfo = 2u
+};
+
 raw_ostream &llvm::gsym::operator<<(raw_ostream &OS, const FunctionInfo &FI) {
   OS << '[' << HEX64(FI.Range.Start) << '-' << HEX64(FI.Range.End) << "): "
      << "Name=" << HEX32(FI.Name) << '\n' << FI.OptLineTable << FI.Inline;
   return OS;
 }
+
+llvm::Expected<FunctionInfo> FunctionInfo::decode(DataExtractor &Data,
+                                                  uint64_t BaseAddr) {
+  FunctionInfo FI;
+  FI.Range.Start = BaseAddr;
+  uint64_t Offset = 0;
+  if (!Data.isValidOffsetForDataOfSize(Offset, 4))
+    return createStringError(std::errc::io_error,
+        "0x%8.8" PRIx64 ": missing FunctionInfo Size", Offset);
+  FI.Range.End = FI.Range.Start + Data.getU32(&Offset);
+  if (!Data.isValidOffsetForDataOfSize(Offset, 4))
+    return createStringError(std::errc::io_error,
+        "0x%8.8" PRIx64 ": missing FunctionInfo Name", Offset);
+  FI.Name = Data.getU32(&Offset);
+  if (FI.Name == 0)
+    return createStringError(std::errc::io_error,
+        "0x%8.8" PRIx64 ": invalid FunctionInfo Name value 0x%8.8x",
+        Offset - 4, FI.Name);
+  bool Done = false;
+  while (!Done) {
+    if (!Data.isValidOffsetForDataOfSize(Offset, 4))
+      return createStringError(std::errc::io_error,
+          "0x%8.8" PRIx64 ": missing FunctionInfo InfoType value", Offset);
+    const uint32_t IT = Data.getU32(&Offset);
+    if (!Data.isValidOffsetForDataOfSize(Offset, 4))
+      return createStringError(std::errc::io_error,
+          "0x%8.8" PRIx64 ": missing FunctionInfo InfoType length", Offset);
+    const uint32_t InfoLength = Data.getU32(&Offset);
+    if (!Data.isValidOffsetForDataOfSize(Offset, InfoLength))
+      return createStringError(std::errc::io_error,
+          "0x%8.8" PRIx64 ": missing FunctionInfo data for InfoType %u",
+          Offset, IT);
+    DataExtractor InfoData(Data.getData().substr(Offset, InfoLength),
+                           Data.isLittleEndian(),
+                           Data.getAddressSize());
+    switch (IT) {
+      case InfoType::EndOfList:
+        Done = true;
+        break;
+
+      case InfoType::LineTableInfo:
+        if (Expected<LineTable> LT = LineTable::decode(InfoData, BaseAddr))
+          FI.OptLineTable = std::move(LT.get());
+        else
+          return LT.takeError();
+        break;
+
+      case InfoType::InlineInfo:
+        if (Expected<InlineInfo> II = InlineInfo::decode(InfoData, BaseAddr))
+          FI.Inline = std::move(II.get());
+        else
+          return II.takeError();
+        break;
+
+      default:
+        return createStringError(std::errc::io_error,
+                                 "0x%8.8" PRIx64 ": unsupported InfoType %u",
+                                 Offset-8, IT);
+    }
+    Offset += InfoLength;
+  }
+  return std::move(FI);
+}
+
+llvm::Expected<uint64_t> FunctionInfo::encode(FileWriter &O) const {
+  if (!isValid())
+    return createStringError(std::errc::invalid_argument,
+        "attempted to encode invalid FunctionInfo object");
+  // Align FunctionInfo data to a 4 byte alignment.
+  O.alignTo(4);
+  const uint64_t FuncInfoOffset = O.tell();
+  // Write the size in bytes of this function as a uint32_t. This can be zero
+  // if we just have a symbol from a symbol table and that symbol has no size.
+  O.writeU32(size());
+  // Write the name of this function as a uint32_t string table offset.
+  O.writeU32(Name);
+
+  if (OptLineTable.hasValue()) {
+    O.writeU32(InfoType::LineTableInfo);
+    // Write a uint32_t length as zero for now, we will fix this up after
+    // writing the LineTable out with the number of bytes that were written.
+    O.writeU32(0);
+    const auto StartOffset = O.tell();
+    llvm::Error err = OptLineTable->encode(O, Range.Start);
+    if (err)
+      return std::move(err);
+    const off_t Length = O.tell() - StartOffset;
+    if (Length > UINT32_MAX)
+        return createStringError(std::errc::invalid_argument,
+            "LineTable length is greater than UINT32_MAX");
+    // Fixup the size of the LineTable data with the correct size.
+    O.fixup32(static_cast<uint32_t>(Length), StartOffset - 4);
+  }
+
+  // Write out the inline function info if we have any and if it is valid.
+  if (Inline.hasValue()) {
+    O.writeU32(InfoType::InlineInfo);
+    // Write a uint32_t length as zero for now, we will fix this up after
+    // writing the LineTable out with the number of bytes that were written.
+    O.writeU32(0);
+    const auto StartOffset = O.tell();
+    llvm::Error err = Inline->encode(O, Range.Start);
+    if (err)
+      return std::move(err);
+    const off_t Length = O.tell() - StartOffset;
+    if (Length > UINT32_MAX)
+        return createStringError(std::errc::invalid_argument,
+            "InlineInfo length is greater than UINT32_MAX");
+    // Fixup the size of the InlineInfo data with the correct size.
+    O.fixup32(static_cast<uint32_t>(Length), StartOffset - 4);
+  }
+
+  // Terminate the data chunks with and end of list with zero size
+  O.writeU32(InfoType::EndOfList);
+  O.writeU32(0);
+  return FuncInfoOffset;
+}