position independent executable (-pie) for arm(cortex-m3)

Question

I'm programming for stm32 (Cortex-m3) with codesourcery g++ lite(based on gcc4.7.2 version). And I want the executables to be loaded dynamically. I knew I have two options available:
1. relocatable elf, which needs a elf parser.
2. position independent code (PIC) with a global offset register

I prefer PIC with global offset register, because it seems it's easier to implement and I'm not familiar with elf or any elf library. Also, It's easy to generate a .bin file from an elf file with some tools.

I've tried building my program with "-msingle-pic-base -fpic" compiling options and "-pie" linking options, but then I got a linking error:

...path...ld.exe: ...path...thumb2\\libstdc++.a(pure.o): relocation R_ARM_THM_MOVW_ABS_NC against `a local symbol' can not be used when making a shared object; recompile with -fPIC

I don't quite understand the error message. It seems the default standard c/c++ library can't go with my options and I need to get the source of the library and rebuild for my own purpose.
So,
1. Could anyone provide me any useful information/link on how to work with the position independent executable ?
2. with the -msingle-pic-base option, I don't need to care too much about the GOT and ld script anymore, right?

Note: Without the "-pie" linking option I can build the program. But the program fails when calling a c++ virtual function (when I'm using the IDE(keil)'s simulator to debug my program). I don't understand what's going on and what I've been missing.

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-- added 20130314

1. with the -msingle-pic-base option, I don't need to care too much about the GOT and ld script anymore, right?

From my experiments, the register (r9 is used in my program) should point to the beginning of the got.plt sections . Delete the "-pie" option, the linking will success, (with r9 properly set) then the c++ virtual function is called successfully. However, I still think the "-pie" option is important, which may ensure that the current standard library is position independent. Could anyone explain this for me?

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-- added 20130315
I took a look at the documents on ABI from ARM's website. But it was of little help because they are not targeting a specific platform. There seems to be a concept of EABI (I'm using sourcery's arm-none-eabi edition), but I couldn't find any documentation on "EABI" from arm's website. I can't neither find documentation on this topic from sourcery and gcc's. There're more than one implementation of PIC, so which one is the sourcery g++ using in the none-eabi case? I think the behaviors of the "-msingle-pic-base", "-fpie", "-pie" options are so poorly documented !
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From the dis-assembly code, I just figured out that, whit the "-msingle-pic-base", the r9 should point to the base address of the ".got" section, the pointers in the .got sections are absolute pointer and the addressing of variable is similar to the description in the article : Position Independent Code (PIC) in shared libraries . So I still need to modify the ".got" sections on loading. I don't know what is the ".got.plt" section used for in my program. It seems that function calls are using PC-relative addressing.
How to build with the "-pie" or how to link a standard library compiled with "-fpic" is still a problem for me .

Answer 1

The error message tells you to recompile the libstdc++ library, which is most often built, when the gcc compiler is built.

Thus you must recompile your standard libraries (libstdc++, libgcc_*, libc, libm and the all) with -fPIC and link your project against them.

If you rely on prebuilt compiler packages, you're mostly out of the game in the microcontroller world. If you build your compiler yourself (which is, by the way, not too difficult, but an advanced/expert task) you are on the go.

It is also possible to compile your stdandard libraries yourself with the compiler you have. You will need the sources of libraries and figure out, how the compiler package build system builds them and you have to mimic this. Perhaps here are some experts, who can advise you on this way.