While we're on the subject of linkers... What is it about linkers these days and relocatable code placed at upload time ? I can't seem to get an absolute code listing anymore. Freescale (code terrorist) , IAR (arm) for example. How are they "located" at upload time ? Can I still get listings with meaningful code placement ? Thanks, bob On 17 May 2006 17:54:11 +0200, David Brown <david@westcontrol.removethisbit.com> wrote:>Dirk Zabel wrote: >> Hi, >> I am using the IAR toolchain for our Renesas M16C based project. The >> device uses a lot of configuration data which are stored within an >> eeprom. In order to define the placement, I have something like this: >> eeprom.c: >> #pragma dataseg="E2PROM_DATA" >> #define extern /* empty */ >> #include "eeprom.h" >> #pragma dataseg=default >> /* EOF */ >> and >> eeprom.h: >> extern __no_init unsigned char MBUS_exist; >> extern __no_init char E2_VERSION_TEXT[20]; >> extern __no_init unsigned char CAN_exists; >> extern __no_init unsigned char MBUS_exists; >> /* and so on. */ >> /* EOF */ >> > >Any code which uses the preprocessor to redefine a keyword like "extern" >is incorrect code. It doesn't matter whether it works or not - it's >still so bad that any experienced reviewer would reject it outright. > > >> I tell the linker to place the E2PROM_DATA segment where the eeprom is >> mapped into the address space and can use the data from other c sources >> by including eeprom.h >> BUT >> The linker throws away all variables in eeprom.h which are not used >> anywhere in the projet (there is NO OPTIMIZATION selected!!). This is >> really bad, since I need a stable address mapping for all configuration >> data; there might be parameters which may be needed in later software >> versions; sometimes I build testversions which do not contain all parts. >> I allways need the variables at the same adresses. >> >> I did already asked the IAR support, but did not get a usable answer >> (they told me to use volatile, but this does not change anything). >> > >IAR support are not famed for being helpful - on the other hand, their >tools are well known for making correct and efficient code. The >compiler (and linker) is doing exactly the right thing - if you declare >variables that are never used, then the compiler and/or linker is free >to remove them - they have no effect on the running of your program. >You might think that the declarations have an effect on the addressing >in eeprom - but that is not true. The order you declare or define data >has no defined effect on the order in memory. For many targets, >compilers will re-order the data for better alignment or padding. So >even if you manage to persuade the tools to keep the unused data, you >are getting a false sense of security - a new compilation could >re-arrange the data. > >The easiest way to get the effect you are looking for is to define a >single structure for all the eeprom-based data, and ensure that it is >linked to one specific address (solution "a" below). If you want to >access struct members without having to add "s." in front of them, you >could use #defines to avoid it (although it is almost certainly best to >correct the old code rather than add hacks around it). > >Solution (b) would not work (as explained above). Solution (c) is >perfectly reasonable (although more effort than (a)), and solution (d) >is again possible, but lots of effort to do well. > > >> I see the following approaches: >> a) define a big struct which contains all variables and put that struct >> into E2PROM_DATA >> b) put dummy references to all variables into my project >> c) define the variables in some assembler source. >> d) the IAR toolchain allows to put variables at numerically known >> addresses, I could place every variable at some pre-calculated address >> >> a) I would have to change all code referring to (say) E2_VERSION_TEXT to >> s.E2_VERSION_TEXT (where s is the name of the struct variable). Since my >> project contains lot of old code, this is not very good. >> b) ugly, blows up my project with "useless" code (the linker is quite >> "smart", you have to DO something with a variable or the code is >> optimized away). >> c) ugly and dangerous, I have to keep the assembler definitions and c >> declarations in sync. >> d) IMHO address calculations should be done by tools, not by programmes >> due to possible errors. >> >> Has anyone some better idea? >> >> >> Greetings >> Dirk Zabel >>
IAR linker: too smart
Started by ●May 16, 2006
Reply by ●May 17, 20062006-05-17
Reply by ●May 17, 20062006-05-17
bob <bob@> wrote:>... >Freescale (code terrorist) ,...May I ask why that label? (I am not using Freescale tools at this time, but one never knows.)
Reply by ●May 18, 20062006-05-18
On Wed, 17 May 2006 19:57:05 -0400, Roberto Waltman <usenet@rwaltman.net> wrote:> bob <bob@> wrote: >>... >>Freescale (code terrorist) ,... > >May I ask why that label? (I am not using Freescale tools at this >time, but one never knows.)There are several things I don't like about it, but especially the DSP 56FXXX compiler version... I couldn't get the output I wanted, like a decent list output file, let alone an absolute listing (which is why my question) Their support sucked for this version where I had lots of questions... No forums or users groups to ask questions really... When I did try to ask questions on a small yahoo group, no answers. And the forum was moderated so my question didn't show up for a few days. When I sent in questions to support at freescale, it would take 6 days to get an answer and then they wouldn't usually understand my question so it took another 4 to 6 days to get another answer. Not always the right answer. Other little things about the interface they need to clean up as well. I also just got through with a project using CW for a 9S08QG8 project but it didn't give me too many problems, luckily except that I was happy to be able to remove it the other day finally. However, Code Warrior leave MANY MANY entries in the windows registry and after uninstalling either version, I have to run a registry cleaner afterwards to remove all the entries. Otherwise, the PC will run slower. THAT's terror ! That's part of it anyway. bob
Reply by ●May 18, 20062006-05-18
In article <in7o6295mvc4fcauap587fd40hrdr4bb77@4ax.com>, bob <bob@> says...> On Wed, 17 May 2006 19:57:05 -0400, Roberto Waltman > <usenet@rwaltman.net> wrote: > > > bob <bob@> wrote: > >>... > >>Freescale (code terrorist) ,... > > > >May I ask why that label? (I am not using Freescale tools at this > >time, but one never knows.)Code Terrorist, play on the real name Code Warrior.> > There are several things I don't like about it, but especially the DSP > 56FXXX compiler version... I couldn't get the output I wanted, like > a decent list output file, let alone an absolute listing (which is why > my question) > Their support sucked for this version where I had lots of questions... > No forums or users groups to ask questions really... When I did try > to ask questions on a small yahoo group, no answers. And the forum > was moderated so my question didn't show up for a few days. > > When I sent in questions to support at freescale, it would take 6 days > to get an answer and then they wouldn't usually understand my question > so it took another 4 to 6 days to get another answer. Not always the > right answer. > Other little things about the interface they need to clean up as well. > > I also just got through with a project using CW for a 9S08QG8 project > but it didn't give me too many problems, luckily except that I was > happy to be able to remove it the other day finally. > However, Code Warrior leave MANY MANY entries in the windows > registry and after uninstalling either version, I have to run a > registry cleaner afterwards to remove all the entries. Otherwise, the > PC will run slower. THAT's terror ! > > > That's part of it anyway. > bob >Add, CW also registers itself as the default program to open about 25 different file types. MAYBE OK, if you only used their tools, but how many of us use multiple tools from many different vendors. CW (Metrowerks) is the only tool chain that I have ever loaded that assumes you run only their tools. I am still finding messed up file associations 2 years later. Jim
Reply by ●May 18, 20062006-05-18
On Thu, 18 May 2006 10:31:37 -0400, James Beck <jim@reallykillersystems.com> wrote:>Add, CW also registers itself as the default program to open about 25 >different file types. MAYBE OK, if you only used their tools, but how >many of us use multiple tools from many different vendors. CW >(Metrowerks) is the only tool chain that I have ever loaded that assumes >you run only their tools. I am still finding messed up file >associations 2 years later. > > Jim >I believe that cleaning the registry after CW has been un-installed will help with the file name associations. I'd better take a look myself though. bob>In article <in7o6295mvc4fcauap587fd40hrdr4bb77@4ax.com>, bob <bob@> >says... >> On Wed, 17 May 2006 19:57:05 -0400, Roberto Waltman >> <usenet@rwaltman.net> wrote: >> >> > bob <bob@> wrote: >> >>... >> >>Freescale (code terrorist) ,... >> > >> >May I ask why that label? (I am not using Freescale tools at this >> >time, but one never knows.) > >Code Terrorist, play on the real name Code Warrior. > >> >> There are several things I don't like about it, but especially the DSP >> 56FXXX compiler version... I couldn't get the output I wanted, like >> a decent list output file, let alone an absolute listing (which is why >> my question) >> Their support sucked for this version where I had lots of questions... >> No forums or users groups to ask questions really... When I did try >> to ask questions on a small yahoo group, no answers. And the forum >> was moderated so my question didn't show up for a few days. >> >> When I sent in questions to support at freescale, it would take 6 days >> to get an answer and then they wouldn't usually understand my question >> so it took another 4 to 6 days to get another answer. Not always the >> right answer. >> Other little things about the interface they need to clean up as well. >> >> I also just got through with a project using CW for a 9S08QG8 project >> but it didn't give me too many problems, luckily except that I was >> happy to be able to remove it the other day finally. >> However, Code Warrior leave MANY MANY entries in the windows >> registry and after uninstalling either version, I have to run a >> registry cleaner afterwards to remove all the entries. Otherwise, the >> PC will run slower. THAT's terror ! >> >> >> That's part of it anyway. >> bob >> >
Reply by ●May 18, 20062006-05-18
In article <t2hp625q8desgrfcmr7916qr11bkbpvur0@4ax.com>, bob <bob@> says...> On Thu, 18 May 2006 10:31:37 -0400, James Beck > <jim@reallykillersystems.com> wrote: > > > > >Add, CW also registers itself as the default program to open about 25 > >different file types. MAYBE OK, if you only used their tools, but how > >many of us use multiple tools from many different vendors. CW > >(Metrowerks) is the only tool chain that I have ever loaded that assumes > >you run only their tools. I am still finding messed up file > >associations 2 years later. > > > > Jim > > > > I believe that cleaning the registry after CW has been un-installed > will help with the file name associations. I'd better take a look > myself though. > > bobIf you have to use the CW stuff then that isn't an option. I have to support some older PalmOS stuff so un-installing it isn't an option.> > > > > > > > >In article <in7o6295mvc4fcauap587fd40hrdr4bb77@4ax.com>, bob <bob@> > >says... > >> On Wed, 17 May 2006 19:57:05 -0400, Roberto Waltman > >> <usenet@rwaltman.net> wrote: > >> > >> > bob <bob@> wrote: > >> >>... > >> >>Freescale (code terrorist) ,... > >> > > >> >May I ask why that label? (I am not using Freescale tools at this > >> >time, but one never knows.) > > > >Code Terrorist, play on the real name Code Warrior. > > > >> > >> There are several things I don't like about it, but especially the DSP > >> 56FXXX compiler version... I couldn't get the output I wanted, like > >> a decent list output file, let alone an absolute listing (which is why > >> my question) > >> Their support sucked for this version where I had lots of questions... > >> No forums or users groups to ask questions really... When I did try > >> to ask questions on a small yahoo group, no answers. And the forum > >> was moderated so my question didn't show up for a few days.
