C ++ character analysis: how to determine which static initialization is performed?

Question

I want to analyze what causes the huge size of my shared C ++ library, which is compiled by GCC (v.6.1.1) on Linux.

readelf -sW libfoo.sosays these are especially large functions, called __static_initialization_and_destruction_0for example:

000000000026c420 10272 FUNC    LOCAL  DEFAULT   12 __static_initialization_and_destruction_0(int, int) [clone .constprop.1774]

I added flags -Wl,-Map,foo.mapin CXXto create the linker map file. A search 0x000000000026c420in this map file gives:

.text.startup  0x000000000026c420     0x2825 CMakeFiles/foo.dir/bar.cpp.o

So now I know that bar.cpp- this is a translation unit that causes static initialization, but the specified file does not contain any variables static. However, it includes many headlines.

How to find out which variables are statically initialized in these functions?

Answer 1

: -g3 -Wa, -adhln

. - :

_Z41__static_initialization_and_destruction_0ii:

, , (ret).

:

struct Foo {
    Foo() {}
};

static Foo a;
static Foo b;

Compile:

g++ text.cpp -c -O0 -g3 -Wa,-ahln > out.txt

:

35              _Z41__static_initialization_and_destruction_0ii:
36                  .LFB3:
3:text.cpp      **** };
4:text.cpp      **** 
5:text.cpp      **** static Foo a;
6:text.cpp      **** static Foo b;
37                      .loc 1 6 0
38                      .cfi_startproc
39 0000 55              pushq   %rbp
40                      .cfi_def_cfa_offset 16
41                      .cfi_offset 6, -16
42 0001 4889E5          movq    %rsp, %rbp
43                      .cfi_def_cfa_register 6
44 0004 4883EC10        subq    $16, %rsp
45 0008 897DFC          movl    %edi, -4(%rbp)
46 000b 8975F8          movl    %esi, -8(%rbp)
47                      .loc 1 6 0
48 000e 837DFC01        cmpl    $1, -4(%rbp)
49 0012 751D            jne .L4
50                      .loc 1 6 0 is_stmt 0 discriminator 1
51 0014 817DF8FF        cmpl    $65535, -8(%rbp)
51      FF0000
52 001b 7514            jne .L4
5:text.cpp      **** struct Foo {
    Foo() {}
};

static Foo a;
static Foo b;

53                      .loc 1 5 0 is_stmt 1 discriminator 3
54 001d BF000000        movl    $_ZL1a, %edi
54      00
55 0022 E8000000        call    _ZN3FooC1Ev
55      00
56                      .loc 1 6 0 discriminator 3
57 0027 BF000000        movl    $_ZL1b, %edi
57      00
58 002c E8000000        call    _ZN3FooC1Ev
58      00
59                  .L4:
60                      .loc 1 6 0 is_stmt 0
61 0031 90              nop
62 0032 C9              leave
63                      .cfi_def_cfa 7, 8
64 0033 C3              ret
65                      .cfi_endproc

54 001d BF000000        movl    $_ZL1a, %edi
57 0027 BF000000        movl    $_ZL1b, %edi

- . ++ filter .

:

call    _ZN3FooC1Ev