19602b7194
Summary: The DWARF transformer is added as a class so it can be unit tested fully. The DWARF is converted to GSYM format and handles many special cases for functions: - omit functions in compile units with 4 byte addresses whose address is UINT32_MAX (dead stripped) - omit functions in compile units with 8 byte addresses whose address is UINT64_MAX (dead stripped) - omit any functions whose high PC is <= low PC (dead stripped) - StringTable builder doesn't copy strings, so we need to make backing copies of strings but only when needed. Many strings come from sections in object files and won't need to have backing copies, but some do. - When a function doesn't have a mangled name, store the fully qualified name by creating a string by traversing the parent decl context DIEs and then. If we don't do this, we end up having cases where some function might appear in the GSYM as "erase" instead of "std::vector<int>::erase". - omit any functions whose address isn't in the optional TextRanges member variable of DwarfTransformer. This allows object file to register address ranges that are known valid code ranges and can help omit functions that should have been dead stripped, but just had their low PC values set to zero. In this case we have many functions that all appear at address zero and can omit these functions by making sure they fall into good address ranges on the object file. Many compilers do this when the DWARF has a DW_AT_low_pc with a DW_FORM_addr, and a DW_AT_high_pc with a DW_FORM_data4 as the offset from the low PC. In this case the linker can't write the same address to both the high and low PC since there is only a relocation for the DW_AT_low_pc, so many linkers tend to just zero it out. Reviewers: aprantl, dblaikie, probinson Subscribers: mgorny, hiraditya, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D74450
253 lines
9.4 KiB
C++
253 lines
9.4 KiB
C++
//===- FunctionInfo.cpp ---------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/DebugInfo/GSYM/FunctionInfo.h"
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#include "llvm/DebugInfo/GSYM/FileWriter.h"
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#include "llvm/DebugInfo/GSYM/GsymReader.h"
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#include "llvm/DebugInfo/GSYM/LineTable.h"
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#include "llvm/DebugInfo/GSYM/InlineInfo.h"
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#include "llvm/Support/DataExtractor.h"
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using namespace llvm;
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using namespace gsym;
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/// FunctionInfo information type that is used to encode the optional data
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/// that is associated with a FunctionInfo object.
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enum InfoType : uint32_t {
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EndOfList = 0u,
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LineTableInfo = 1u,
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InlineInfo = 2u
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};
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raw_ostream &llvm::gsym::operator<<(raw_ostream &OS, const FunctionInfo &FI) {
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OS << FI.Range << ": " << "Name=" << HEX32(FI.Name) << '\n';
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if (FI.OptLineTable)
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OS << FI.OptLineTable << '\n';
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if (FI.Inline)
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OS << FI.Inline << '\n';
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return OS;
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}
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llvm::Expected<FunctionInfo> FunctionInfo::decode(DataExtractor &Data,
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uint64_t BaseAddr) {
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FunctionInfo FI;
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FI.Range.Start = BaseAddr;
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uint64_t Offset = 0;
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if (!Data.isValidOffsetForDataOfSize(Offset, 4))
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return createStringError(std::errc::io_error,
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"0x%8.8" PRIx64 ": missing FunctionInfo Size", Offset);
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FI.Range.End = FI.Range.Start + Data.getU32(&Offset);
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if (!Data.isValidOffsetForDataOfSize(Offset, 4))
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return createStringError(std::errc::io_error,
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"0x%8.8" PRIx64 ": missing FunctionInfo Name", Offset);
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FI.Name = Data.getU32(&Offset);
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if (FI.Name == 0)
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return createStringError(std::errc::io_error,
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"0x%8.8" PRIx64 ": invalid FunctionInfo Name value 0x%8.8x",
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Offset - 4, FI.Name);
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bool Done = false;
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while (!Done) {
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if (!Data.isValidOffsetForDataOfSize(Offset, 4))
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return createStringError(std::errc::io_error,
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"0x%8.8" PRIx64 ": missing FunctionInfo InfoType value", Offset);
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const uint32_t IT = Data.getU32(&Offset);
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if (!Data.isValidOffsetForDataOfSize(Offset, 4))
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return createStringError(std::errc::io_error,
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"0x%8.8" PRIx64 ": missing FunctionInfo InfoType length", Offset);
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const uint32_t InfoLength = Data.getU32(&Offset);
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if (!Data.isValidOffsetForDataOfSize(Offset, InfoLength))
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return createStringError(std::errc::io_error,
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"0x%8.8" PRIx64 ": missing FunctionInfo data for InfoType %u",
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Offset, IT);
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DataExtractor InfoData(Data.getData().substr(Offset, InfoLength),
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Data.isLittleEndian(),
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Data.getAddressSize());
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switch (IT) {
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case InfoType::EndOfList:
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Done = true;
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break;
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case InfoType::LineTableInfo:
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if (Expected<LineTable> LT = LineTable::decode(InfoData, BaseAddr))
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FI.OptLineTable = std::move(LT.get());
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else
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return LT.takeError();
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break;
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case InfoType::InlineInfo:
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if (Expected<InlineInfo> II = InlineInfo::decode(InfoData, BaseAddr))
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FI.Inline = std::move(II.get());
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else
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return II.takeError();
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break;
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default:
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return createStringError(std::errc::io_error,
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"0x%8.8" PRIx64 ": unsupported InfoType %u",
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Offset-8, IT);
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}
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Offset += InfoLength;
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}
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return std::move(FI);
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}
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llvm::Expected<uint64_t> FunctionInfo::encode(FileWriter &O) const {
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if (!isValid())
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return createStringError(std::errc::invalid_argument,
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"attempted to encode invalid FunctionInfo object");
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// Align FunctionInfo data to a 4 byte alignment.
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O.alignTo(4);
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const uint64_t FuncInfoOffset = O.tell();
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// Write the size in bytes of this function as a uint32_t. This can be zero
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// if we just have a symbol from a symbol table and that symbol has no size.
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O.writeU32(size());
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// Write the name of this function as a uint32_t string table offset.
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O.writeU32(Name);
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if (OptLineTable.hasValue()) {
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O.writeU32(InfoType::LineTableInfo);
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// Write a uint32_t length as zero for now, we will fix this up after
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// writing the LineTable out with the number of bytes that were written.
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O.writeU32(0);
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const auto StartOffset = O.tell();
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llvm::Error err = OptLineTable->encode(O, Range.Start);
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if (err)
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return std::move(err);
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const auto Length = O.tell() - StartOffset;
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if (Length > UINT32_MAX)
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return createStringError(std::errc::invalid_argument,
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"LineTable length is greater than UINT32_MAX");
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// Fixup the size of the LineTable data with the correct size.
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O.fixup32(static_cast<uint32_t>(Length), StartOffset - 4);
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}
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// Write out the inline function info if we have any and if it is valid.
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if (Inline.hasValue()) {
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O.writeU32(InfoType::InlineInfo);
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// Write a uint32_t length as zero for now, we will fix this up after
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// writing the LineTable out with the number of bytes that were written.
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O.writeU32(0);
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const auto StartOffset = O.tell();
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llvm::Error err = Inline->encode(O, Range.Start);
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if (err)
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return std::move(err);
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const auto Length = O.tell() - StartOffset;
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if (Length > UINT32_MAX)
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return createStringError(std::errc::invalid_argument,
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"InlineInfo length is greater than UINT32_MAX");
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// Fixup the size of the InlineInfo data with the correct size.
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O.fixup32(static_cast<uint32_t>(Length), StartOffset - 4);
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}
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// Terminate the data chunks with and end of list with zero size
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O.writeU32(InfoType::EndOfList);
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O.writeU32(0);
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return FuncInfoOffset;
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}
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llvm::Expected<LookupResult> FunctionInfo::lookup(DataExtractor &Data,
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const GsymReader &GR,
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uint64_t FuncAddr,
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uint64_t Addr) {
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LookupResult LR;
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LR.LookupAddr = Addr;
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LR.FuncRange.Start = FuncAddr;
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uint64_t Offset = 0;
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LR.FuncRange.End = FuncAddr + Data.getU32(&Offset);
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uint32_t NameOffset = Data.getU32(&Offset);
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// The "lookup" functions doesn't report errors as accurately as the "decode"
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// function as it is meant to be fast. For more accurage errors we could call
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// "decode".
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if (!Data.isValidOffset(Offset))
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return createStringError(std::errc::io_error,
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"FunctionInfo data is truncated");
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// This function will be called with the result of a binary search of the
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// address table, we must still make sure the address does not fall into a
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// gap between functions are after the last function.
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if (Addr >= LR.FuncRange.End)
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return createStringError(std::errc::io_error,
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"address 0x%" PRIx64 " is not in GSYM", Addr);
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if (NameOffset == 0)
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return createStringError(std::errc::io_error,
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"0x%8.8" PRIx64 ": invalid FunctionInfo Name value 0x00000000",
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Offset - 4);
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LR.FuncName = GR.getString(NameOffset);
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bool Done = false;
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Optional<LineEntry> LineEntry;
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Optional<DataExtractor> InlineInfoData;
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while (!Done) {
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if (!Data.isValidOffsetForDataOfSize(Offset, 8))
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return createStringError(std::errc::io_error,
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"FunctionInfo data is truncated");
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const uint32_t IT = Data.getU32(&Offset);
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const uint32_t InfoLength = Data.getU32(&Offset);
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const StringRef InfoBytes = Data.getData().substr(Offset, InfoLength);
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if (InfoLength != InfoBytes.size())
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return createStringError(std::errc::io_error,
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"FunctionInfo data is truncated");
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DataExtractor InfoData(InfoBytes, Data.isLittleEndian(),
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Data.getAddressSize());
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switch (IT) {
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case InfoType::EndOfList:
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Done = true;
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break;
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case InfoType::LineTableInfo:
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if (auto ExpectedLE = LineTable::lookup(InfoData, FuncAddr, Addr))
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LineEntry = ExpectedLE.get();
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else
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return ExpectedLE.takeError();
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break;
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case InfoType::InlineInfo:
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// We will parse the inline info after our line table, but only if
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// we have a line entry.
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InlineInfoData = InfoData;
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break;
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default:
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break;
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}
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Offset += InfoLength;
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}
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if (!LineEntry) {
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// We don't have a valid line entry for our address, fill in our source
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// location as best we can and return.
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SourceLocation SrcLoc;
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SrcLoc.Name = LR.FuncName;
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LR.Locations.push_back(SrcLoc);
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return LR;
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}
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Optional<FileEntry> LineEntryFile = GR.getFile(LineEntry->File);
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if (!LineEntryFile)
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return createStringError(std::errc::invalid_argument,
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"failed to extract file[%" PRIu32 "]",
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LineEntry->File);
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SourceLocation SrcLoc;
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SrcLoc.Name = LR.FuncName;
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SrcLoc.Dir = GR.getString(LineEntryFile->Dir);
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SrcLoc.Base = GR.getString(LineEntryFile->Base);
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SrcLoc.Line = LineEntry->Line;
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LR.Locations.push_back(SrcLoc);
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// If we don't have inline information, we are done.
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if (!InlineInfoData)
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return LR;
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// We have inline information. Try to augment the lookup result with this
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// data.
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llvm::Error Err = InlineInfo::lookup(GR, *InlineInfoData, FuncAddr, Addr,
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LR.Locations);
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if (Err)
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return std::move(Err);
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return LR;
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}
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