98456a64b0
BPF considers that every call to a function allocates a fresh set of registers that are available to the callee, of which the first five may have bee initialized with the function arguments. This is implemented by both interpreter and JIT in the Linux kernel. This is enforced by the kernel BPF verifier, which will reject any code in which non-initialized registers are accessed before being written. Consequently, the spill instructions generated in function prologue were causing the verifier to reject our compiled programs. This patch makes GCC to not save/restore callee-saved registers in function prologue/epilogue, unless xBPF mode is enabled. 2020-05-19 Jose E. Marchesi <jose.marchesi@oracle.com> gcc/ * config/bpf/bpf.c (bpf_compute_frame_layout): Include space for callee saved registers only in xBPF. (bpf_expand_prologue): Save callee saved registers only in xBPF. (bpf_expand_epilogue): Likewise for restoring. * doc/invoke.texi (eBPF Options): Document this is activated by -mxbpf. gcc/testsuite/ * gcc.target/bpf/xbpf-callee-saved-regs-1.c: New test. * gcc.target/bpf/xbpf-callee-saved-regs-2.c: Likewise. |
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config | ||
contrib | ||
fixincludes | ||
gcc | ||
gnattools | ||
gotools | ||
include | ||
INSTALL | ||
intl | ||
libada | ||
libatomic | ||
libbacktrace | ||
libcc1 | ||
libcpp | ||
libdecnumber | ||
libffi | ||
libgcc | ||
libgfortran | ||
libgo | ||
libgomp | ||
libhsail-rt | ||
libiberty | ||
libitm | ||
libobjc | ||
liboffloadmic | ||
libphobos | ||
libquadmath | ||
libsanitizer | ||
libssp | ||
libstdc++-v3 | ||
libvtv | ||
lto-plugin | ||
maintainer-scripts | ||
zlib | ||
.dir-locals.el | ||
.gitattributes | ||
.gitignore | ||
ABOUT-NLS | ||
ar-lib | ||
ChangeLog | ||
ChangeLog.jit | ||
ChangeLog.tree-ssa | ||
compile | ||
config-ml.in | ||
config.guess | ||
config.rpath | ||
config.sub | ||
configure | ||
configure.ac | ||
COPYING | ||
COPYING3 | ||
COPYING3.LIB | ||
COPYING.LIB | ||
COPYING.RUNTIME | ||
depcomp | ||
install-sh | ||
libtool-ldflags | ||
libtool.m4 | ||
lt~obsolete.m4 | ||
ltgcc.m4 | ||
ltmain.sh | ||
ltoptions.m4 | ||
ltsugar.m4 | ||
ltversion.m4 | ||
MAINTAINERS | ||
Makefile.def | ||
Makefile.in | ||
Makefile.tpl | ||
missing | ||
mkdep | ||
mkinstalldirs | ||
move-if-change | ||
multilib.am | ||
README | ||
symlink-tree | ||
test-driver | ||
ylwrap |
This directory contains the GNU Compiler Collection (GCC). The GNU Compiler Collection is free software. See the files whose names start with COPYING for copying permission. The manuals, and some of the runtime libraries, are under different terms; see the individual source files for details. The directory INSTALL contains copies of the installation information as HTML and plain text. The source of this information is gcc/doc/install.texi. The installation information includes details of what is included in the GCC sources and what files GCC installs. See the file gcc/doc/gcc.texi (together with other files that it includes) for usage and porting information. An online readable version of the manual is in the files gcc/doc/gcc.info*. See http://gcc.gnu.org/bugs/ for how to report bugs usefully. Copyright years on GCC source files may be listed using range notation, e.g., 1987-2012, indicating that every year in the range, inclusive, is a copyrightable year that could otherwise be listed individually.