Question

我能够通过llvm-cov以json格式导出代码覆盖率数据，但是内容对我来说似乎很神秘。 segments部分中的每个数字是什么意思？

{
   "filename":"file.m",
   "segments":[
      [
         11,
         22,
         23,
         1,
         1
      ],
      [
         12,
         11,
         23,
         1,
         1
      ],
      ...
   ],
   "expansions":[

   ],
   "summary":{
      ...
   }
}

Answer 1

按照https://clang.llvm.org/docs/SourceBasedCodeCoverage.html进行操作，JSON格式在源代码中进行了解释，我在https://github.com/llvm-mirror/llvm/tree/master/tools/llvm-cov上找到了源代码。

source code包含以下描述：

The json code coverage export follows the following format
Root: dict => Root Element containing metadata
-- Data: array => Homogeneous array of one or more export objects
    -- Export: dict => Json representation of one CoverageMapping
    -- Files: array => List of objects describing coverage for files
        -- File: dict => Coverage for a single file
        -- Segments: array => List of Segments contained in the file
            -- Segment: dict => Describes a segment of the file with a counter
        -- Expansions: array => List of expansion records
            -- Expansion: dict => Object that descibes a single expansion
            -- CountedRegion: dict => The region to be expanded
            -- TargetRegions: array => List of Regions in the expansion
                -- CountedRegion: dict => Single Region in the expansion
        -- Summary: dict => Object summarizing the coverage for this file
            -- LineCoverage: dict => Object summarizing line coverage
            -- FunctionCoverage: dict => Object summarizing function coverage
            -- RegionCoverage: dict => Object summarizing region coverage
    -- Functions: array => List of objects describing coverage for functions
        -- Function: dict => Coverage info for a single function
        -- Filenames: array => List of filenames that the function relates to
    -- Summary: dict => Object summarizing the coverage for the entire binary
    -- LineCoverage: dict => Object summarizing line coverage
    -- FunctionCoverage: dict => Object summarizing function coverage
    -- InstantiationCoverage: dict => Object summarizing inst. coverage
    -- RegionCoverage: dict => Object summarizing region coverage

遗憾的是，这仍然不是关于段是什么或其结构的解释。

仔细看一下代码，我们发现以下两个片段：

json::Array renderSegment(const coverage::CoverageSegment &Segment) {
  return json::Array({Segment.Line, Segment.Col, int64_t(Segment.Count),
                      Segment.HasCount, Segment.IsRegionEntry});
}

json::Array renderRegion(const coverage::CountedRegion &Region) {
  return json::Array({Region.LineStart, Region.ColumnStart, Region.LineEnd,
                      Region.ColumnEnd, int64_t(Region.ExecutionCount),
                      Region.FileID, Region.ExpandedFileID,
                      int64_t(Region.Kind)});
}

哪个应该让您更好地了解条目的含义。

文件ID似乎索引到扩展名中提供的文件名中。

Answer 2

除了先前的答案，我还发现此页面非常有用：page。它有助于解释segment中的每个概念，例如line，column。

如何读取llvm-cov json格式？

2 个答案: