x-sysv4

gcc-2.95.3 Linux下最常用的C编译器

# The svr4 reference port for the i860 contains an alloca.o routine
# in /usr/ucblib/libucb.a, but we can't just try to get that by
# setting CLIB to /usr/ucblib/libucb.a because (unfortunately)
# there are a lot of other routines in libucb.a which are supposed
# to be the Berkeley versions of library routines normally found in
# libc.a and many of these Berkeley versions are badly broken.  Thus,
# if we try to link programs with libucb.a before libc.a, those
# programs tend to crash.

# Also, the alloca() routine supplied in early version of svr4 for
# the i860 is non-ABI compliant.  It doesn't keep the stack aligned
# to a 16-byte boundary as the ABI requires.

# More importantly however, even a fully ABI compliant alloca() routine
# would fail to work correctly with some versions of the native svr4 C
# compiler currently being distributed for the i860 (as of 1/29/92).
# The problem is that the native C compiler generates non-ABI-compliant
# function epilogues which cut back the stack (upon function exit) in
# an incorrect manner.  Specifically, they cut back the stack by adding
# the nominal *static* frame size (determined statically at compile-time)
# to the stack pointer rather than setting the stack pointer based upon
# the current value of the frame pointer (as called for in the i860 ABI).
# This can cause serious trouble in cases where you repeatedly call a
# routine which itself calls alloca().  In such cases, the stack will
# grow continuously until you finally run out of swap space or exceed
# the system's process size limit.  To avoid this problem (which can
# arise when a stage1 gcc is being used to build a stage2 gcc) you
# *must* link in the C language version of alloca() which is supplied
# with gcc to your stage1 version of gcc.  The following definition
# forces that to happen.

ALLOCA=alloca.o

# We build all stages *without* shared libraries because that may make
# debugging the compiler easier (until there is a GDB which supports
# both Dwarf *and* svr4 shared libraries).

# Note that the native C compiler for the svr4 reference port on the
# i860 recognizes a special -gg option.  Using that option causes *full*
# Dwarf debugging information to be generated, whereas using only -g
# causes only limited Dwarf debugging information to be generated.
# (This is an undocumented feature of the native svr4 C compiler.)

CCLIBFLAGS=-Bstatic -dn -gg