[Bug gcov-profile/105238] Regression: using -fprofile-dir: gcno files not ccache cachable anymore / gcovr report broken

[esgergn at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105238

--- Comment #6 from Esger Abbink <esgergn at hotmail dot com> ---
After patching ccache 4.5.1 to understand -fprofile-prefix-map it does cache .o
and .gcno:

$ ccache -z -C

$ cd /home/esger/src/application/coverage_test/dir1/source/ && CCACHE_DEBUG=
CCACHE_BASEDIR=/home/esger/src/application/coverage_test/dir1 ccache
/usr/bin/g++-9.4p --coverage
-fprofile-prefix-map=/home/esger/src/application/coverage_test/dir1=.
-fdebug-prefix-map=/home/esger/src/application/coverage_test/dir1=. -c
/home/esger/src/application/coverage_test/dir1/source/main.cpp

$ ccache -s
Summary:
  Hits:               0 /    1 (0.00 %)
    Direct:           0 /    1 (0.00 %)
    Preprocessed:     0 /    1 (0.00 %)
  Misses:             1
    Direct:           1
    Preprocessed:     1
Primary storage:
  Hits:               0 /    2 (0.00 %)
  Misses:             2
  Cache size (GB): 0.00 / 5.00 (0.00 %)
  Cleanups:           4

$ cd /home/esger/src/application/coverage_test/dir2/source/ && CCACHE_DEBUG=
CCACHE_BASEDIR=/home/esger/src/application/coverage_test/dir2 ccache
/usr/bin/g++-9.4p --coverage
-fprofile-prefix-map=/home/esger/src/application/coverage_test/dir2=.
-fdebug-prefix-map=/home/esger/src/application/coverage_test/dir2=. -c
/home/esger/src/application/coverage_test/dir2/source/main.cpp

$ ccache -s
Summary:
  Hits:               1 /    2 (50.00 %)
    Direct:           1 /    2 (50.00 %)
    Preprocessed:     0 /    1 (0.00 %)
  Misses:             1
    Direct:           1
    Preprocessed:     1
Primary storage:
  Hits:               2 /    4 (50.00 %)
  Misses:             2
  Cache size (GB): 0.00 / 5.00 (0.00 %)
  Cleanups:           4

Using the cached .o/.gcno also generates a gcda in the correct location:

$ cd /home/esger/src/application/coverage_test/dir2/source/ && CCACHE_DEBUG=
CCACHE_BASEDIR=/home/esger/src/application/coverage_test/dir2 ccache
/usr/bin/g++-9.4p --coverage
-fprofile-prefix-map=/home/esger/src/application/coverage_test/dir2=.
-fdebug-prefix-map=/home/esger/src/application/coverage_test/dir2=. main.o -o
../bin/a.out

$ cd /home/esger/src/application/coverage_test/dir2 && ./bin/a.out

$ ls source/
main.cpp  main.gcda  main.gcno  main.o

$ gcovr --html coverage.html .
[ coverage report OK ]



Though the gcno of source still contains a wrong CWD:

$ gcov-dump-9.4p source/main.gcno |more
main.gcno:note:magic `gcno':version `A94*'
main.gcno:stamp 761679940
main.gcno:cwd: /home/esger/src/application/coverage_test/dir1/source
main.gcno:  01000000:  20:FUNCTION ident=1826217343,
lineno_checksum=0x36a9d8e5, cfg_checksum=0xc0bbb23e, `_GLOBAL__sub_I__Z5funcAi'
main.cpp:21:1-21:1, artificial
main.gcno:    01410000:   1:BLOCKS 4 blocks
main.gcno:    01430000:   3:ARCS 1 arcs
main.gcno:    01430000:   5:ARCS 2 arcs
main.gcno:    01430000:   3:ARCS 1 arcs
main.gcno:    01450000:   9:LINES
main.gcno:    01450000:   9:LINES
...


Not sure though what (negative) impact that will/could have?