https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123891
Bug ID: 123891
Summary: Some functions entirely missing from gcov results
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: gcov-profile
Assignee: unassigned at gcc dot gnu.org
Reporter: tromey at gcc dot gnu.org
Target Milestone: ---
I'm using the Fedora 41 system gcc, though this problem
has affected the last few Fedora releases at least.
bapiya. gcc --version
gcc (GCC) 14.3.1 20251022 (Red Hat 14.3.1-4)
I used to regularly run gcov on gdb but now I find the results
are unreliable. Some functions -- which I am absolutely sure
are being called -- are recorded as having no execution.
I do not have a smaller test case but it is very easy to reproduce
if you have gdb.
Configure like so:
bapiya. ./config.status --version
config.status
configured by ../binutils-gdb/configure, generated by GNU Autoconf 2.69,
with options "'--disable-binutils' '--disable-gas' '--disable-gold'
'--disable-gprof' '--disable-gprofng' '--disable-ld' '--disable-sim'
'CFLAGS=-fprofile-arcs -ftest-coverage -g -O0' 'CXXFLAGS=-fprofile-arcs
-ftest-coverage -g -O0'"
This configures a relatively minimal gdb.
Then build: "make -j10" or whatever.
Then, run just the rust tests:
cd $build/gdb/testsuite
make site.exp
runtest --directory gdb.rust
After this, examine rust-lang.c:
cd $build/gdb
gcov -m rust-lang.c
less rust-lang.c.gcov
I see many functions marked with "#####".
However I know most of these are called when the Rust tests are
run, and in the past I've debugged gdb to be 100% certain.
E.g.:
-: 70:static bool
#####: 71:rust_enum_p (struct type *type)
-: 72:{
-: 73: /* is_dynamic_type will return true if any field has a
dynamic
-: 74: attribute -- but we only want to check the top level. */
#####: 75: return TYPE_HAS_VARIANT_PARTS (type);
-: 76:}
