Hi Kumar,
When building the MPC8572DS_config w/gcc-4.4 I get:
sys_eeprom.c: In function ‘do_mac’: sys_eeprom.c:323: warning: dereferencing type-punned pointer will break strict-aliasing rules sys_eeprom.c: In function ‘mac_read_from_eeprom’: sys_eeprom.c:395: warning: dereferencing type-punned pointer will break strict-aliasing rules ahci.c: In function ‘ata_scsiop_read_capacity10’: ahci.c:616: warning: dereferencing type-punned pointer will break strict-aliasing rules biosemu.c: In function ‘BE_setVGA’: biosemu.c:147: warning: dereferencing type-punned pointer will break strict-aliasing rules tsec.c: In function ‘tsec_init’: tsec.c:200: warning: dereferencing type-punned pointer will break strict-aliasing rules dlmalloc.c: In function ‘malloc_bin_reloc’: dlmalloc.c:1502: warning: dereferencing pointer ‘p’ does break strict- aliasing rules dlmalloc.c:1502: warning: dereferencing pointer ‘p’ does break strict- aliasing rules dlmalloc.c:1499: note: initialized from here dlmalloc.c:1502: note: initialized from here dlmalloc.c: In function ‘free’: dlmalloc.c:2474: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2474: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2474: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2474: note: initialized from here dlmalloc.c: In function ‘malloc’: dlmalloc.c:2219: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2219: note: initialized from here dlmalloc.c:2228: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2228: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2228: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2228: note: initialized from here dlmalloc.c:2235: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2235: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2235: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2235: note: initialized from here dlmalloc.c:2292: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2292: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2292: warning: dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules dlmalloc.c:2292: note: initialized from here
You already fixed quite a few problems in dlmalloc:
commit 57c219ad5d34dd9d49991777a62e3899595f2ec7 Author: Kumar Gala galak@kernel.crashing.org Date: Wed Jul 30 08:01:15 2008 -0500
Fix compile warnings in dlmalloc
The origional code was using on odd reference to get to the first real element in av_[]. The first two elements of the array are not used for actual bins, but for house keeping. If we are more explicit about how use the first few elements we can get rid of the warnings:
dlmalloc.c: In function 'malloc_extend_top': dlmalloc.c:1971: warning: dereferencing type-punned pointer will break strict-aliasing rules dlmalloc.c:1999: warning: dereferencing type-punned pointer will break strict-aliasing rules dlmalloc.c:2029: warning: dereferencing type-punned pointer will break strict-aliasing rules ...
The logic of how this code came to be is: bin_at(0) = (char*)&(av_[2]) - 2*SIZE_SZ
SIZE_SZ is the size of pointer, and av_ is arry of pointers so: bin_at(0) = &(av_[0])
Going from there to bin_at(0)->fd or bin_at(0)->size should be straight forward.
Signed-off-by: Kumar Gala galak@kernel.crashing.org
xyzModem.c: In function ‘xyzModem_stream_open’: xyzModem.c:564: warning: ‘dummy’ is used uninitialized in this function xyzModem.c:547: note: ‘dummy’ was declared here
Should would be turning on -fno-strict-aliasing. The linux kernel has been doing this for some time.
Last time around, i.e. moving to gcc 4.x (as proven by the commit above), we were able to fix the problems. Did anything significantly change in the arguments?
Cheers Detlev