【发布时间】：2016-11-23 13:14:39
【问题描述】：
我生成覆盖数据并使用在线服务进行可视化和 CI。但是我有奇怪的“部分”（没有完全覆盖的 if 分支）。查看 gcov 数据，似乎检测到了过多的分支。
一个例子：
function _ZNK5World8AdjustBQE5PointItEh15BuildingQuality called 415 returned 100% blocks executed 76%
415: 377:BuildingQuality World::AdjustBQ(const MapPoint pt, unsigned char player, BuildingQuality nodeBQ) const
-: 378:{
415: 379: if(nodeBQ == BQ_NOTHING || GetNode(pt).owner != player + 1 || !IsPlayerTerritory(pt))
branch 0 taken 95% (fallthrough)
branch 1 taken 5%
call 2 returned 100%
call 3 returned 100%
branch 4 taken 100% (fallthrough)
branch 5 taken 0% (throw)
branch 6 taken 85% (fallthrough)
branch 7 taken 15%
call 8 returned 100%
call 9 returned 100%
branch 10 taken 100% (fallthrough)
branch 11 taken 0% (throw)
branch 12 taken 17% (fallthrough)
branch 13 taken 83%
branch 14 taken 80% (fallthrough)
branch 15 taken 20%
branch 16 taken 95% (fallthrough)
branch 17 taken 5%
branch 18 taken 33% (fallthrough)
branch 19 taken 67%
branch 20 never executed
branch 21 never executed
branch 22 never executed
branch 23 never executed
call 24 never executed
虽然我已经在使用-g -O0 --coverage -fno-default-inline -fno-inline 进行编译，但这些函数似乎仍然被内联和计数。我该怎么办，所以我只能得到“有意义的”数据，并且内联函数在其定义中被正确归因？
我正在使用 g++-4.8 和 gcov-4.8
编辑：如果我将 if 拆分为它的调用，我会得到：
415: 379: unsigned char owner = GetNode(pt).owner;
call 0 returned 100%
call 1 returned 100%
branch 2 taken 100% (fallthrough)
branch 3 taken 0% (throw)
call 4 never executed
415: 380: bool isPlayerTer = IsPlayerTerritory(pt);
call 0 returned 100%
call 1 returned 100%
branch 2 taken 100% (fallthrough)
branch 3 taken 0% (throw)
call 4 never executed
415: 381: if(nodeBQ == BQ_NOTHING || owner != player + 1 || !isPlayerTer)
branch 0 taken 95% (fallthrough)
branch 1 taken 5%
branch 2 taken 85% (fallthrough)
branch 3 taken 15%
branch 4 taken 17% (fallthrough)
branch 5 taken 83%
所以问题真的出在电话上。我该怎么做才能使这些调用（及其分支 (???)）不被添加到覆盖数据中？
刚刚在 asm 代码中发现了一个人工分支，它只检查一个寄存器并执行 nop（除了 gcov 计数器增量）WTF？
0x0000000000d967de <World::AdjustBQ(Point<unsigned short>, unsigned char, BuildingQuality) const+340>: test %bl,%bl
0x0000000000d967e0 <World::AdjustBQ(Point<unsigned short>, unsigned char, BuildingQuality) const+342>: je 0xd967f5 <World::AdjustBQ(Point<unsigned short>, unsigned char, BuildingQuality) const+363>
0x0000000000d967e2 <World::AdjustBQ(Point<unsigned short>, unsigned char, BuildingQuality) const+344>: nop
0x0000000000d967e3 <World::AdjustBQ(Point<unsigned short>, unsigned char, BuildingQuality) const+345>: mov 0x1206c9e(%rip),%rax # 0x1f9d488 <__gcov0._ZNK5World8AdjustBQE5PointItEh15BuildingQuality+72>
0x0000000000d967ea <World::AdjustBQ(Point<unsigned short>, unsigned char, BuildingQuality) const+352>: add $0x1,%rax
0x0000000000d967ee <World::AdjustBQ(Point<unsigned short>, unsigned char, BuildingQuality) const+356>: mov %rax,0x1206c93(%rip) # 0x1f9d488 <__gcov0._ZNK5World8AdjustBQE5PointItEh15BuildingQuality+72>
0x0000000000d967f5 <World::AdjustBQ(Point<unsigned short>, unsigned char, BuildingQuality) const+363>: test %dl,%dl
我切换到 clang++ 和 llvm-cov gcov 并得到了这个案例的正确结果（只有 6 个分支）。然而，我在其他地方也得到了一些误报。最令人不安的一个似乎是“函数 __cxx_global_array_dtor 调用”，位于函数中间的类似行（仅更改整数参数）没有这个的行。所以我目前的解决方案是使用没有分支数据的 gcov-4.8，因为它完全不可靠。
【问题讨论】：
标签： c++ code-coverage gcov