[cfe-dev] Compiling xv6 with Clang

[Csaba Raduly via cfe-dev]

Hi Ahmad,


On Fri, Nov 9, 2018 at 12:08 AM Ahmad Nouralizadeh Khorrami via
cfe-dev <cfe-dev at lists.llvm.org> wrote:
>
> Hi David,
> The problem is still there. The sequence of commands to build the bootblock (for gcc) is as follows:
> gcc -fno-pic -static -fno-builtin -fno-strict-aliasing -O2 -Wall -MD -ggdb -m32 -Werror -fno-omit-frame-pointer -fno-stack-protector -fno-pic -O -nostdinc -I. -c bootmain.c

You seem to have a -O towards the end of the command line, which would
override the earlier -O2 . Is this intentional?

You have two object files (bootmain.o and bootasm.o). Compare the
sizes generated by gcc and clang for both object files.

You could use -save-temps when compiling the .c file to look at the
generated assembly and try to spot differences between clang and GCC.

Csaba
-- 
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So if you're looking for a completely portable, 100% standards-conformat way
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