llvm-project/lldb/source/Core/FileSpecList.cpp
Pavel Labath 3f35ab8b30 SymbolFileBreakpad: Add line table support
Summary:
This patch teaches SymbolFileBreakpad to parse the line information in
breakpad files and present it to lldb.

The trickiest question here was what kind of "compile units" to present
to lldb, as there really isn't enough information in breakpad files to
correctly reconstruct those.

A couple of options were considered
- have the entire file be one compile unit
- have one compile unit for each FILE record
- have one compile unit for each FUNC record

The main drawback of the first approach is that all of the files would
be considered "headers" by lldb, and so they wouldn't be searched if
target.inline-breakpoint-strategy=never. The single compile unit would
also be huge, and there isn't a good way to name it.

The second approach will create mostly correct compile units for cpp
files, but it will still be wrong for headers. However, the biggest
drawback here seemed to be the fact that this can cause a compile unit
to change mid-function (for example when a function from another file is
inlined or another file is #included into a function). While I don't
know of any specific thing that would break in this case, it does sound
like a thing that we should avoid.

In the end, we chose the third option, as it didn't seem to have any
major disadvantages, though it was not ideal either. One disadvantage
here is that this generates a large number of compile units, and there
is still a question on how to name it. We chose to simply name it after
the first line record in that function. This should be correct 99.99% of
the time, though it can produce somewhat strange results if the very
first line record comes from an #included file.

Reviewers: clayborg, zturner, lemo, markmentovai

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D56595

llvm-svn: 353404
2019-02-07 13:42:32 +00:00

138 lines
5.1 KiB
C++

//===-- FileSpecList.cpp ----------------------------------------*- C++ -*-===//
//
// 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 "lldb/Core/FileSpecList.h"
#include "lldb/Utility/ConstString.h"
#include "lldb/Utility/Stream.h"
#include <utility>
#include <stdint.h>
using namespace lldb_private;
using namespace std;
FileSpecList::FileSpecList() : m_files() {}
FileSpecList::~FileSpecList() = default;
//------------------------------------------------------------------
// Append the "file_spec" to the end of the file spec list.
//------------------------------------------------------------------
void FileSpecList::Append(const FileSpec &file_spec) {
m_files.push_back(file_spec);
}
//------------------------------------------------------------------
// Only append the "file_spec" if this list doesn't already contain it.
//
// Returns true if "file_spec" was added, false if this list already contained
// a copy of "file_spec".
//------------------------------------------------------------------
bool FileSpecList::AppendIfUnique(const FileSpec &file_spec) {
collection::iterator end = m_files.end();
if (find(m_files.begin(), end, file_spec) == end) {
m_files.push_back(file_spec);
return true;
}
return false;
}
//------------------------------------------------------------------
// Clears the file list.
//------------------------------------------------------------------
void FileSpecList::Clear() { m_files.clear(); }
//------------------------------------------------------------------
// Dumps the file list to the supplied stream pointer "s".
//------------------------------------------------------------------
void FileSpecList::Dump(Stream *s, const char *separator_cstr) const {
collection::const_iterator pos, end = m_files.end();
for (pos = m_files.begin(); pos != end; ++pos) {
pos->Dump(s);
if (separator_cstr && ((pos + 1) != end))
s->PutCString(separator_cstr);
}
}
//------------------------------------------------------------------
// Find the index of the file in the file spec list that matches "file_spec"
// starting "start_idx" entries into the file spec list.
//
// Returns the valid index of the file that matches "file_spec" if it is found,
// else std::numeric_limits<uint32_t>::max() is returned.
//------------------------------------------------------------------
size_t FileSpecList::FindFileIndex(size_t start_idx, const FileSpec &file_spec,
bool full) const {
const size_t num_files = m_files.size();
// When looking for files, we will compare only the filename if the FILE_SPEC
// argument is empty
bool compare_filename_only = file_spec.GetDirectory().IsEmpty();
for (size_t idx = start_idx; idx < num_files; ++idx) {
if (compare_filename_only) {
if (ConstString::Equals(
m_files[idx].GetFilename(), file_spec.GetFilename(),
file_spec.IsCaseSensitive() || m_files[idx].IsCaseSensitive()))
return idx;
} else {
if (FileSpec::Equal(m_files[idx], file_spec, full))
return idx;
}
}
// We didn't find the file, return an invalid index
return UINT32_MAX;
}
//------------------------------------------------------------------
// Returns the FileSpec object at index "idx". If "idx" is out of range, then
// an empty FileSpec object will be returned.
//------------------------------------------------------------------
const FileSpec &FileSpecList::GetFileSpecAtIndex(size_t idx) const {
if (idx < m_files.size())
return m_files[idx];
static FileSpec g_empty_file_spec;
return g_empty_file_spec;
}
const FileSpec *FileSpecList::GetFileSpecPointerAtIndex(size_t idx) const {
if (idx < m_files.size())
return &m_files[idx];
return nullptr;
}
//------------------------------------------------------------------
// Return the size in bytes that this object takes in memory. This returns the
// size in bytes of this object's member variables and any FileSpec objects its
// member variables contain, the result doesn't not include the string values
// for the directories any filenames as those are in shared string pools.
//------------------------------------------------------------------
size_t FileSpecList::MemorySize() const {
size_t mem_size = sizeof(FileSpecList);
collection::const_iterator pos, end = m_files.end();
for (pos = m_files.begin(); pos != end; ++pos) {
mem_size += pos->MemorySize();
}
return mem_size;
}
//------------------------------------------------------------------
// Return the number of files in the file spec list.
//------------------------------------------------------------------
size_t FileSpecList::GetSize() const { return m_files.size(); }
size_t FileSpecList::GetFilesMatchingPartialPath(const char *path,
bool dir_okay,
FileSpecList &matches) {
return 0;
}