GCC_EXEC_PREFIX behavior doesn't match the manual or reason and several ways.
The manual says GCC_EXEC_PREFIX is a prefix for the program name, which means
'gcc' should look for 'cc1' as GCC_EXEC_PREFIX/cc1. But Strace indicates that
'gcc' looks at GCC_EXEC_PREFIX/MACHINE/VERSION/../../../..
MACHINE/bin/MACHINE/VERSION/cc1.
This is a rather strange path.
The manual says gcc looks using GCC_EXEC_PREFIX first, and then the usual
places. That would be normal. For me, it looks in a bunch of places unrelated
to GCC_EXEC_PREFIX, then the path described above, then gives up.
The "bunch of places" mentioned above starts with something that is apparently
based on the path by which 'gcc' was invoked, but has too many .. in it:
MY_GCC_INSTALL_DIRECTORY/lib/../../lbiexec/gcc/MACHINE/VERSION/cc1.
On the other hand, if I don't set GCC_EXEC_PREFIX, it properly looks at
MY_GCC_INSTALL_DIRECTORY/bin/../libexec/gcc/MACHINE/VERSION/cc1.
The manual says GCC_EXEC_PREFIX is used for finding subprograms and linker
files, but it is apparently also used for the specs file --
GCC_EXEC_PREFIX/MACHINE/VERSION/specs .
The manual says the default for GCC_EXEC_PREFIX is PREFIX/lib/gcc . But it
also
says when GCC_EXEC_PREFIX is not set, gcc searches based on the pathname with
which it was invoked. The latter matches what the program does for me.
(For clarity, I have written the above as if gcc add a slash after
GCC_EXEC_PREFIX; as documented, it doesn't).
Note that in these experiments, I built gcc with PREFIX = nonexistent directory
to ensure no built-in path gets used.
Finally, if someone works on the manual section, I highly recommend moving the
environment variable section out of the "Gcc Command Options" section. It
doesn't fit there; I had a hard time finding it.
--
Summary: GCC_EXEC_PREFIX used wrong
Product: gcc
Version: 3.4.3
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: driver
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: bryanh at giraffe-data dot com
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19856
