https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85350
Bug ID: 85350
Summary: [GCOV] wrong coverage when using constant variable in
struct declaration
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: gcov-profile
Assignee: unassigned at gcc dot gnu.org
Reporter: yangyibiao at nju dot edu.cn
CC: marxin at gcc dot gnu.org
Target Milestone: ---
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
8-20170923-1ubuntu2' --with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs
--enable-languages=c,c++,go,brig,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-8
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie
--with-system-zlib --enable-objc-gc=auto --enable-multiarch --disable-werror
--with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32
--enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 8.0.0 20170923 (experimental) [trunk revision 253118] (Ubuntu
8-20170923-1ubuntu2)
$ cat small.c
#include <stdio.h>
int main (void)
{
const int t = 2;
struct s1 {
int x;
int g[t];
};
struct s2 {
int x;
int g[2];
};
printf("Sucess!\n");
return 0;
}
$ gcc --coverage small.c; ./a.out; gcov-8 small.c; cat small.c.gcov
Sucess!
File 'small.c'
Lines executed:100.00% of 6
Creating 'small.c.gcov'
-: 0:Source:small.c
-: 0:Graph:small.gcno
-: 0:Data:small.gcda
-: 0:Runs:1
-: 0:Programs:1
-: 1:#include <stdio.h>
-: 2:
1: 3:int main (void)
-: 4:{
1: 5: const int t = 2;
2: 6: struct s1 {
-: 7: int x;
1: 8: int g[t];
-: 9: };
-: 10:
-: 11: struct s2 {
-: 12: int x;
-: 13: int g[2];
-: 14: };
-: 15:
1: 16: printf("Sucess!\n");
1: 17: return 0;
-: 18:}
Line #6 is wrongly marked as executed twice.
The second struct declaration is not using constant variable t. By comparing
these two structs, we can know that constant variable should be the reason that
leads to the incorrect coverage.
