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Jose E. Marchesi 98456a64b0 bpf: do not save/restore callee-saved registers in function prolog/epilog
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.
2020-05-19 11:46:40 +02:00
config bootstrap: Update requirement to C++11. 2020-05-18 14:29:18 -04:00
contrib New mklog script. 2020-05-19 11:40:55 +02:00
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gcc bpf: do not save/restore callee-saved registers in function prolog/epilog 2020-05-19 11:46:40 +02:00
gnattools
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include Do not use HAVE_DOS_BASED_FILE_SYSTEM for Cygwin. 2020-04-17 09:22:51 +02:00
INSTALL
intl intl: Unbreak intl build with bison 3 when no regeneration is needed [PR92008] 2020-04-16 11:55:00 +02:00
libada
libatomic x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
libbacktrace x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
libcc1 x86: Default CET run-time support to auto 2020-05-14 09:05:02 -07:00
libcpp Update cpplib sv.po. 2020-05-15 22:40:40 +00:00
libdecnumber x86: Default CET run-time support to auto 2020-05-14 09:05:02 -07:00
libffi libffi/test: Fix compilation for build sysroot 2020-04-25 21:27:14 +01:00
libgcc x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
libgfortran x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
libgo libgo: only build syscall test with -static if it works 2020-05-15 15:33:20 -07:00
libgomp openmp: Add basic library allocator support. 2020-05-19 10:11:01 +02:00
libhsail-rt
libiberty libiberty: Handle @live attribute in D demangler. 2020-05-15 10:40:47 +02:00
libitm x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
libobjc x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
liboffloadmic Add missing ChangeLog entries. 2020-05-05 16:10:13 +02:00
libphobos libphobos: Merge upstream druntime 5cc061a8, phobos 64ed4684f 2020-05-17 18:49:19 +02:00
libquadmath x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
libsanitizer x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
libssp x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
libstdc++-v3 c++: Explain fn template argument type/value mismatches [PR66439] 2020-05-18 23:50:14 -04:00
libvtv x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
lto-plugin Enable CET in cross compiler if possible 2020-05-12 10:39:54 -07:00
maintainer-scripts Adjust crontab. 2020-04-30 19:25:03 +02:00
zlib x86: Also check if -fcf-protection works 2020-05-15 09:07:17 -07:00
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ltmain.sh Do not use HAVE_DOS_BASED_FILE_SYSTEM for Cygwin. 2020-04-17 09:22:51 +02:00
ltoptions.m4
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MAINTAINERS MAINTAINERS: Add myself for write after approval. 2020-05-18 12:21:17 +01:00
Makefile.def Merge top-level configury changes from gdb 2020-04-09 06:52:55 -06:00
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