ubuntu - gprof 产生空输出

Question

我正在运行 Ubuntu 16.10 并尝试使用 gprof 分析程序。我用标志 -pg 编译，程序是单线程的。实际的编译命令是:

g++ -I. -std=c++11 -Wall -Wextra -O3 -pg -fPIC -Wno-unused-parameter -c -o build/obj/performance/stencil_application.o test/performance/stencil_application.cpp
g++ -I. -std=c++11 -Wall -Wextra -O3 -pg -Wno-unused-parameter build/obj/performance/stencil_application.o -o build/test/performance/stencil_application

程序在我运行时需要几秒钟才能完成，并生成一个名为 gmon.out 的文件。但是，当我运行 gprof ./build/test/performance/stencil_application 时，我得到的输出不包含任何数字。我只得到表标题和不同字段的解释，如下所示:

Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total           
 time   seconds   seconds    calls  Ts/call  Ts/call  name    

 %         the percentage of the total running time of the
time       program used by this function.

cumulative a running sum of the number of seconds accounted
 seconds   for by this function and those listed above it.

 self      the number of seconds accounted for by this
seconds    function alone.  This is the major sort for this
           listing.

calls      the number of times this function was invoked, if
           this function is profiled, else blank.

 self      the average number of milliseconds spent in this
ms/call    function per call, if this function is profiled,
           else blank.

 total     the average number of milliseconds spent in this
ms/call    function and its descendents per call, if this
           function is profiled, else blank.

name       the name of the function.  This is the minor sort
           for this listing. The index shows the location of
           the function in the gprof listing. If the index is
           in parenthesis it shows where it would appear in
           the gprof listing if it were to be printed.

Copyright (C) 2012-2016 Free Software Foundation, Inc.

Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.

                     Call graph (explanation follows)


granularity: each sample hit covers 2 byte(s) no time propagated

index % time    self  children    called     name

 This table describes the call tree of the program, and was sorted by
 the total amount of time spent in each function and its children.

等等。

我也试过在不使用 -O3 和使用 -g 的情况下进行编译，但结果相同。有人知道怎么回事吗？

Answer 1

正如 Tony Beta Lambda 在上面的评论中所指出的，这是一个 bug in gcc .有两种可能的解决方法:降级到 gcc-4.9，或使用标记 -no-pie 进行编译。