+++ /dev/null
-
-
-Brian
-Gallew
-
-
-Transcribed 1998-02-12
-
-
-
gcc Default Optimizations
-
-
-
-
-
-
-Configuring gcc to use certain flags by default is a simple matter of
-editing the
-/usr/local/lib/gcc-lib/platform/version/specs
-file.
-The format of this file pretty simple. The file is broken into
-sections, each of which is three lines long. The first line is
-"*section_name:" (e.g. "*asm:").
-The second line is a list of flags,
-and the third line is blank.
-
-
-The easiest change to make is to append
-the desired default flags to the list in the appropriate section. As
-an example, let's suppose that I have linux running on a '486 with gcc
-2.7.2 installed in the default location. In the file
-/usr/local/lib/gcc-lib/i486-linux/2.7.2/specs, 13 lines down I find
-the following section:
-- ----------SECTION----------
-*cc1:
-
-
-- ----------SECTION----------
-
-As you can see, there aren't any default flags. If I always wanted
-compiles of C code to use "-m486 -fomit-frame-pointer", I would
-change it to look like:
-- ----------SECTION----------
-*cc1:
-- -m486 -fomit-frame-pointer
-
-- ----------SECTION----------
-
-If I wanted to be able to generate 386 code for another, older linux
-box lying around, I'd have to make it look like this:
-- ----------SECTION----------
-*cc1:
-%{!m386:-m486} -fomit-frame-pointer
-
-- ----------SECTION----------
-
-This will always omit frame pointers, any will build 486-optimized
-code unless -m386 is specified on the command line.
-
-
-You can actually do quite a lot of customization with the specs file.
-Always remember, however, that these changes are global, and affect
-all users of the system.
-
-
-