https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93735
Bug ID: 93735
Summary: [GCOV] incorrect coverage for calling variable
arguments function with incremental expression in its
parameter list
Product: gcc
Version: 9.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: gcov-profile
Assignee: unassigned at gcc dot gnu.org
Reporter: yangyibiao at hust dot edu.cn
CC: marxin at gcc dot gnu.org
Target Milestone: ---
$ gcov -v
gcov (GCC) 9.2.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/9.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --enable-shared
--enable-threads=posix --with-system-zlib --with-isl --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch
--disable-libssp --enable-gnu-unique-object --enable-linker-build-id
--enable-lto --enable-plugin --enable-install-libiberty
--with-linker-hash-style=gnu --enable-gnu-indirect-function --enable-multilib
--disable-werror --enable-checking=release --enable-default-pie
--enable-default-ssp --enable-cet=auto gdc_include_dir=/usr/include/dlang/gdc
Thread model: posix
gcc version 9.2.0 (GCC)
$ cat small.c
int v = 8;
__attribute__((noinline)) int foo(int x, int y, ...) { return x; }
inline __attribute__((always_inline, gnu_inline)) int bar(int x, ...) { return
foo(x, 1, 2); }
int main(void)
{
bar(0, ++v, 1);
if (bar(0, ++v, 1) != 0)
return 1;
return 0;
}
$ gcc -O0 -g --coverage small.c; ./a.out; gcov small.c; cat small.c.gcov
File 'small.c'
Lines executed:71.43% of 7
Creating 'small.c.gcov'
-: 0:Source:small.c
-: 0:Graph:small.gcno
-: 0:Data:small.gcda
-: 0:Runs:1
-: 1:int v = 8;
-: 2:
2: 3:__attribute__((noinline)) int foo(int x, int y, ...) { return x; }
-: 4:
#####: 5:inline __attribute__((always_inline, gnu_inline)) int bar(int x,
...) { return foo(x, 1, 2); }
-: 6:
1: 7:int main(void)
-: 8:{
1: 9: bar(0, ++v, 1);
2: 10: if (bar(0, ++v, 1) != 0)
#####: 11: return 1;
1: 12: return 0;
-: 13:}
################################################################################
### We can find that: Line #9 is marked as executed one time.
### However, Line #10 is wrongly marked as executed two times.
### when removing ++v in its parameter list, the coverage will be correct.
################################################################################
