ada: Pass -msmp when linking for ppc-vx6 --RTS=rtp-smp

gprbuild and gnatmake won't pass --RTS=rtp-smp to the compiler driver
for linking.  The flag was not used during linking: the .spec files
named as linker options were all we passed for the linker to get the
-L flags for lib_smp and lib.

There was a problem, though: although /lib_smp/ and /lib/ were to be
searched in this order, and the specs files did that correctly, the
compiler would search /lib/ first regardless, because
STARTFILE_PREFIX_SPEC said so, and specs files cannot override that.

With this patch, we make sure the rtp-smp runtime causes -msmp to be
added to the command line passed to the compiler driver for linking,
and a corresponding patch for the ppc-vxworks configuration makes the
GCC compiler driver use this flag to select /lib_smp/ rather than
/lib/.

gcc/ada/

	* libgnat/system-vxworks-ppc-rtp-smp.ads: Add -msmp to
	Linker_Options pragma.

• [DBH] gcc/ada/libgnat/system-vxworks-ppc-rtp-smp.ads

Control flow redundancy hardening

This patch introduces an optional hardening pass to catch unexpected
execution flows.  Functions are transformed so that basic blocks set a
bit in an automatic array, and (non-exceptional) function exit edges
check that the bits in the array represent an expected execution path
in the CFG.

Functions with multiple exit edges, or with too many blocks, call an
out-of-line checker builtin implemented in libgcc.  For simpler
functions, the verification is performed in-line.

-fharden-control-flow-redundancy enables the pass for eligible
functions, --param hardcfr-max-blocks sets a block count limit for
functions to be eligible, and --param hardcfr-max-inline-blocks
tunes the "too many blocks" limit for in-line verification.
-fhardcfr-skip-leaf makes leaf functions non-eligible.

Additional -fhardcfr-check-* options are added to enable checking at
exception escape points, before potential sibcalls, hereby dubbed
returning calls, and before noreturn calls and exception raises.  A
notable case is the distinction between noreturn calls expected to
throw and those expected to terminate or loop forever: the default
setting for -fhardcfr-check-noreturn-calls, no-xthrow, performs
checking before the latter, but the former only gets checking in the
exception handler.  GCC can only tell between them by explicit marking
noreturn functions expected to raise with the newly-introduced
expected_throw attribute, and corresponding ECF_XTHROW flag.


for  gcc/ChangeLog

	* tree-core.h (ECF_XTHROW): New macro.
	* tree.cc (set_call_expr): Add expected_throw attribute when
	ECF_XTHROW is set.
	(build_common_builtin_node): Add ECF_XTHROW to
	__cxa_end_cleanup and _Unwind_Resume or _Unwind_SjLj_Resume.
	* calls.cc (flags_from_decl_or_type): Check for expected_throw
	attribute to set ECF_XTHROW.
	* gimple.cc (gimple_build_call_from_tree): Propagate
	ECF_XTHROW from decl flags to gimple call...
	(gimple_call_flags): ... and back.
	* gimple.h (GF_CALL_XTHROW): New gf_mask flag.
	(gimple_call_set_expected_throw): New.
	(gimple_call_expected_throw_p): New.
	* Makefile.in (OBJS): Add gimple-harden-control-flow.o.
	* builtins.def (BUILT_IN___HARDCFR_CHECK): New.
	* common.opt (fharden-control-flow-redundancy): New.
	(-fhardcfr-check-returning-calls): New.
	(-fhardcfr-check-exceptions): New.
	(-fhardcfr-check-noreturn-calls=*): New.
	(Enum hardcfr_check_noreturn_calls): New.
	(fhardcfr-skip-leaf): New.
	* doc/invoke.texi: Document them.
	(hardcfr-max-blocks, hardcfr-max-inline-blocks): New params.
	* flag-types.h (enum hardcfr_noret): New.
	* gimple-harden-control-flow.cc: New.
	* params.opt (-param=hardcfr-max-blocks=): New.
	(-param=hradcfr-max-inline-blocks=): New.
	* passes.def (pass_harden_control_flow_redundancy): Add.
	* tree-pass.h (make_pass_harden_control_flow_redundancy):
	Declare.
	* doc/extend.texi: Document expected_throw attribute.

for  gcc/ada/ChangeLog

	* gcc-interface/trans.cc (gigi): Mark __gnat_reraise_zcx with
	ECF_XTHROW.
	(build_raise_check): Likewise for all rcheck subprograms.

for  gcc/c-family/ChangeLog

	* c-attribs.cc (handle_expected_throw_attribute): New.
	(c_common_attribute_table): Add expected_throw.

for  gcc/cp/ChangeLog

	* decl.cc (push_throw_library_fn): Mark with ECF_XTHROW.
	* except.cc (build_throw): Likewise __cxa_throw,
	_ITM_cxa_throw, __cxa_rethrow.

for  gcc/testsuite/ChangeLog

	* c-c++-common/torture/harden-cfr.c: New.
	* c-c++-common/harden-cfr-noret-never-O0.c: New.
	* c-c++-common/torture/harden-cfr-noret-never.c: New.
	* c-c++-common/torture/harden-cfr-noret-noexcept.c: New.
	* c-c++-common/torture/harden-cfr-noret-nothrow.c: New.
	* c-c++-common/torture/harden-cfr-noret.c: New.
	* c-c++-common/torture/harden-cfr-notail.c: New.
	* c-c++-common/torture/harden-cfr-returning.c: New.
	* c-c++-common/torture/harden-cfr-tail.c: New.
	* c-c++-common/torture/harden-cfr-abrt-always.c: New.
	* c-c++-common/torture/harden-cfr-abrt-never.c: New.
	* c-c++-common/torture/harden-cfr-abrt-no-xthrow.c: New.
	* c-c++-common/torture/harden-cfr-abrt-nothrow.c: New.
	* c-c++-common/torture/harden-cfr-abrt.c: New.
	* c-c++-common/torture/harden-cfr-always.c: New.
	* c-c++-common/torture/harden-cfr-never.c: New.
	* c-c++-common/torture/harden-cfr-no-xthrow.c: New.
	* c-c++-common/torture/harden-cfr-nothrow.c: New.
	* c-c++-common/torture/harden-cfr-bret-always.c: New.
	* c-c++-common/torture/harden-cfr-bret-never.c: New.
	* c-c++-common/torture/harden-cfr-bret-noopt.c: New.
	* c-c++-common/torture/harden-cfr-bret-noret.c: New.
	* c-c++-common/torture/harden-cfr-bret-no-xthrow.c: New.
	* c-c++-common/torture/harden-cfr-bret-nothrow.c: New.
	* c-c++-common/torture/harden-cfr-bret-retcl.c: New.
	* c-c++-common/torture/harden-cfr-bret.c: New.
	* g++.dg/harden-cfr-throw-always-O0.C: New.
	* g++.dg/harden-cfr-throw-returning-O0.C: New.
	* g++.dg/torture/harden-cfr-noret-always-no-nothrow.C: New.
	* g++.dg/torture/harden-cfr-noret-never-no-nothrow.C: New.
	* g++.dg/torture/harden-cfr-noret-no-nothrow.C: New.
	* g++.dg/torture/harden-cfr-throw-always.C: New.
	* g++.dg/torture/harden-cfr-throw-never.C: New.
	* g++.dg/torture/harden-cfr-throw-no-xthrow.C: New.
	* g++.dg/torture/harden-cfr-throw-no-xthrow-expected.C: New.
	* g++.dg/torture/harden-cfr-throw-nothrow.C: New.
	* g++.dg/torture/harden-cfr-throw-nocleanup.C: New.
	* g++.dg/torture/harden-cfr-throw-returning.C: New.
	* g++.dg/torture/harden-cfr-throw.C: New.
	* gcc.dg/torture/harden-cfr-noret-no-nothrow.c: New.
	* gcc.dg/torture/harden-cfr-tail-ub.c: New.
	* gnat.dg/hardcfr.adb: New.

for  libgcc/ChangeLog

	* Makefile.in (LIB2ADD): Add hardcfr.c.
	* hardcfr.c: New.

• [DBH] gcc/ada/gcc-interface/trans.cc

Introduce strub: machine-independent stack scrubbing

This patch adds the strub attribute for function and variable types,
command-line options, passes and adjustments to implement it,
documentation, and tests.

Stack scrubbing is implemented in a machine-independent way: functions
with strub enabled are modified so that they take an extra stack
watermark argument, that they update with their stack use, and the
caller can then zero it out once it regains control, whether by return
or exception.  There are two ways to go about it: at-calls, that
modifies the visible interface (signature) of the function, and
internal, in which the body is moved to a clone, the clone undergoes
the interface change, and the function becomes a wrapper, preserving
its original interface, that calls the clone and then clears the stack
used by it.

Variables can also be annotated with the strub attribute, so that
functions that read from them get stack scrubbing enabled implicitly,
whether at-calls, for functions only usable within a translation unit,
or internal, for functions whose interfaces must not be modified.

There is a strict mode, in which functions that have their stack
scrubbed can only call other functions with stack-scrubbing
interfaces, or those explicitly marked as callable from strub
contexts, so that an entire call chain gets scrubbing, at once or
piecemeal depending on optimization levels.  In the default mode,
relaxed, this requirement is not enforced by the compiler.

The implementation adds two IPA passes, one that assigns strub modes
early on, another that modifies interfaces and adds calls to the
builtins that jointly implement stack scrubbing.  Another builtin,
that obtains the stack pointer, is added for use in the implementation
of the builtins, whether expanded inline or called in libgcc.

There are new command-line options to change operation modes and to
force the feature disabled; it is enabled by default, but it has no
effect and is implicitly disabled if the strub attribute is never
used.  There are also options meant to use for testing the feature,
enabling different strubbing modes for all (viable) functions.


for  gcc/ChangeLog

	* Makefile.in (OBJS): Add ipa-strub.o.
	(GTFILES): Add ipa-strub.cc.
	* builtins.def (BUILT_IN_STACK_ADDRESS): New.
	(BUILT_IN___STRUB_ENTER): New.
	(BUILT_IN___STRUB_UPDATE): New.
	(BUILT_IN___STRUB_LEAVE): New.
	* builtins.cc: Include ipa-strub.h.
	(STACK_STOPS, STACK_UNSIGNED): Define.
	(expand_builtin_stack_address): New.
	(expand_builtin_strub_enter): New.
	(expand_builtin_strub_update): New.
	(expand_builtin_strub_leave): New.
	(expand_builtin): Call them.
	* common.opt (fstrub=*): New options.
	* doc/extend.texi (strub): New type attribute.
	(__builtin_stack_address): New function.
	(Stack Scrubbing): New section.
	* doc/invoke.texi (-fstrub=*): New options.
	(-fdump-ipa-*): New passes.
	* gengtype-lex.l: Ignore multi-line pp-directives.
	* ipa-inline.cc: Include ipa-strub.h.
	(can_inline_edge_p): Test strub_inlinable_to_p.
	* ipa-split.cc: Include ipa-strub.h.
	(execute_split_functions): Test strub_splittable_p.
	* ipa-strub.cc, ipa-strub.h: New.
	* passes.def: Add strub_mode and strub passes.
	* tree-cfg.cc (gimple_verify_flow_info): Note on debug stmts.
	* tree-pass.h (make_pass_ipa_strub_mode): Declare.
	(make_pass_ipa_strub): Declare.
	(make_pass_ipa_function_and_variable_visibility): Fix
	formatting.
	* tree-ssa-ccp.cc (optimize_stack_restore): Keep restores
	before strub leave.
	* attribs.cc: Include ipa-strub.h.
	(decl_attributes): Support applying attributes to function
	type, rather than pointer type, at handler's request.
	(comp_type_attributes): Combine strub_comptypes and target
	comp_type results.
	* doc/tm.texi.in (TARGET_STRUB_USE_DYNAMIC_ARRAY): New.
	(TARGET_STRUB_MAY_USE_MEMSET): New.
	* doc/tm.texi: Rebuilt.
	* cgraph.h (symtab_node::reset): Add preserve_comdat_group
	param, with a default.
	* cgraphunit.cc (symtab_node::reset): Use it.

for  gcc/c-family/ChangeLog

	* c-attribs.cc: Include ipa-strub.h.
	(handle_strub_attribute): New.
	(c_common_attribute_table): Add strub.

for  gcc/ada/ChangeLog

	* gcc-interface/trans.cc: Include ipa-strub.h.
	(gigi): Make internal decls for targets of compiler-generated
	calls strub-callable too.
	(build_raise_check): Likewise.
	* gcc-interface/utils.cc: Include ipa-strub.h.
	(handle_strub_attribute): New.
	(gnat_internal_attribute_table): Add strub.

for  gcc/testsuite/ChangeLog

	* c-c++-common/strub-O0.c: New.
	* c-c++-common/strub-O1.c: New.
	* c-c++-common/strub-O2.c: New.
	* c-c++-common/strub-O2fni.c: New.
	* c-c++-common/strub-O3.c: New.
	* c-c++-common/strub-O3fni.c: New.
	* c-c++-common/strub-Og.c: New.
	* c-c++-common/strub-Os.c: New.
	* c-c++-common/strub-all1.c: New.
	* c-c++-common/strub-all2.c: New.
	* c-c++-common/strub-apply1.c: New.
	* c-c++-common/strub-apply2.c: New.
	* c-c++-common/strub-apply3.c: New.
	* c-c++-common/strub-apply4.c: New.
	* c-c++-common/strub-at-calls1.c: New.
	* c-c++-common/strub-at-calls2.c: New.
	* c-c++-common/strub-defer-O1.c: New.
	* c-c++-common/strub-defer-O2.c: New.
	* c-c++-common/strub-defer-O3.c: New.
	* c-c++-common/strub-defer-Os.c: New.
	* c-c++-common/strub-internal1.c: New.
	* c-c++-common/strub-internal2.c: New.
	* c-c++-common/strub-parms1.c: New.
	* c-c++-common/strub-parms2.c: New.
	* c-c++-common/strub-parms3.c: New.
	* c-c++-common/strub-relaxed1.c: New.
	* c-c++-common/strub-relaxed2.c: New.
	* c-c++-common/strub-short-O0-exc.c: New.
	* c-c++-common/strub-short-O0.c: New.
	* c-c++-common/strub-short-O1.c: New.
	* c-c++-common/strub-short-O2.c: New.
	* c-c++-common/strub-short-O3.c: New.
	* c-c++-common/strub-short-Os.c: New.
	* c-c++-common/strub-strict1.c: New.
	* c-c++-common/strub-strict2.c: New.
	* c-c++-common/strub-tail-O1.c: New.
	* c-c++-common/strub-tail-O2.c: New.
	* c-c++-common/torture/strub-callable1.c: New.
	* c-c++-common/torture/strub-callable2.c: New.
	* c-c++-common/torture/strub-const1.c: New.
	* c-c++-common/torture/strub-const2.c: New.
	* c-c++-common/torture/strub-const3.c: New.
	* c-c++-common/torture/strub-const4.c: New.
	* c-c++-common/torture/strub-data1.c: New.
	* c-c++-common/torture/strub-data2.c: New.
	* c-c++-common/torture/strub-data3.c: New.
	* c-c++-common/torture/strub-data4.c: New.
	* c-c++-common/torture/strub-data5.c: New.
	* c-c++-common/torture/strub-indcall1.c: New.
	* c-c++-common/torture/strub-indcall2.c: New.
	* c-c++-common/torture/strub-indcall3.c: New.
	* c-c++-common/torture/strub-inlinable1.c: New.
	* c-c++-common/torture/strub-inlinable2.c: New.
	* c-c++-common/torture/strub-ptrfn1.c: New.
	* c-c++-common/torture/strub-ptrfn2.c: New.
	* c-c++-common/torture/strub-ptrfn3.c: New.
	* c-c++-common/torture/strub-ptrfn4.c: New.
	* c-c++-common/torture/strub-pure1.c: New.
	* c-c++-common/torture/strub-pure2.c: New.
	* c-c++-common/torture/strub-pure3.c: New.
	* c-c++-common/torture/strub-pure4.c: New.
	* c-c++-common/torture/strub-run1.c: New.
	* c-c++-common/torture/strub-run2.c: New.
	* c-c++-common/torture/strub-run3.c: New.
	* c-c++-common/torture/strub-run4.c: New.
	* c-c++-common/torture/strub-run4c.c: New.
	* c-c++-common/torture/strub-run4d.c: New.
	* c-c++-common/torture/strub-run4i.c: New.
	* g++.dg/strub-run1.C: New.
	* g++.dg/torture/strub-init1.C: New.
	* g++.dg/torture/strub-init2.C: New.
	* g++.dg/torture/strub-init3.C: New.
	* gnat.dg/strub_attr.adb, gnat.dg/strub_attr.ads: New.
	* gnat.dg/strub_ind.adb, gnat.dg/strub_ind.ads: New.

for  libgcc/ChangeLog

	* Makefile.in (LIB2ADD): Add strub.c.
	* libgcc2.h (__strub_enter, __strub_update, __strub_leave):
	Declare.
	* strub.c: New.
	* libgcc-std.ver.in (__strub_enter): Add to GCC_14.0.0.
	(__strub_update, __strub_leave): Likewise.

• [DBH] gcc/ada/gcc-interface/trans.cc
• [DBH] gcc/ada/gcc-interface/utils.cc