Mangling, currently only used on AArch64 for return address signing,
is an internal representation that should not be exposed via
__builtin_return_address return value,
__builtin_eh_return handler argument,
_Unwind_DebugHook handler argument.
Note that a mangled address might not even fit into a void *, e.g.
with AArch64 ilp32 ABI the return address is stored as 64bit, so
the mangled return address cannot be accessed via _Unwind_GetPtr.
This patch changes the unwinder hooks as follows:
MD_POST_EXTRACT_ROOT_ADDR is removed: root address comes from
__builtin_return_address which is not mangled.
MD_POST_EXTRACT_FRAME_ADDR is renamed to MD_DEMANGLE_RETURN_ADDR,
it now operates on _Unwind_Word instead of void *, so the hook
should work when return address signing is enabled on AArch64 ilp32.
(But for that __builtin_aarch64_autia1716 should be fixed to operate
on 64bit input instead of a void *.)
MD_POST_FROB_EH_HANDLER_ADDR is removed: it is the responsibility of
__builtin_eh_return to do the mangling if necessary.
2020-07-13 Szabolcs Nagy <szabolcs.nagy@arm.com>
libgcc/ChangeLog:
PR target/94891
* config/aarch64/aarch64-unwind.h (MD_POST_EXTRACT_ROOT_ADDR): Remove.
(MD_POST_FROB_EH_HANDLER_ADDR): Remove.
(MD_POST_EXTRACT_FRAME_ADDR): Rename to ...
(MD_DEMANGLE_RETURN_ADDR): This.
(aarch64_post_extract_frame_addr): Rename to ...
(aarch64_demangle_return_addr): This.
(aarch64_post_frob_eh_handler_addr): Remove.
* unwind-dw2.c (uw_update_context): Demangle return address.
(uw_frob_return_addr): Remove.
This patch adds support for unwinding frames that use the SVE
pseudo VG register. We want this register to act like a normal
register if the CFI explicitly sets it, but want to provide a
default value otherwise. Computing the default value requires
an SVE target, so we only want to compute it on demand.
aarch64_vg uses a hard-coded .inst in order to avoid a build
dependency on binutils 2.28 or later.
2018-01-13 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
* doc/tm.texi.in (DWARF_LAZY_REGISTER_VALUE): Document.
* doc/tm.texi: Regenerate.
libgcc/
* config/aarch64/value-unwind.h (aarch64_vg): New function.
(DWARF_LAZY_REGISTER_VALUE): Define.
* unwind-dw2.c (_Unwind_GetGR): Use DWARF_LAZY_REGISTER_VALUE
to provide a fallback register value.
gcc/testsuite/
* g++.target/aarch64/sve/aarch64-sve.exp: New harness.
* g++.target/aarch64/sve/catch_1.C: New test.
* g++.target/aarch64/sve/catch_2.C: Likewise.
* g++.target/aarch64/sve/catch_3.C: Likewise.
* g++.target/aarch64/sve/catch_4.C: Likewise.
* g++.target/aarch64/sve/catch_5.C: Likewise.
* g++.target/aarch64/sve/catch_6.C: Likewise.
Reviewed-by: James Greenhalgh <james.greenhalgh@arm.com>
From-SVN: r256615
Control-flow Enforcement Technology (CET), published by Intel,
introduces the Shadow Stack feature, which ensures a return from a
function is done to exactly the same location from where the function
was called. When EH is present the control-flow transfer may skip some
stack frames and the shadow stack has to be adjusted not to signal a
violation of a control-flow transfer. It's done by counting a number
of skiping frames and adjasting shadow stack pointer by this number.
Having new semantic of the 'ret' instruction if CET is supported in HW
the 'ret' instruction cannot be generated in ix86_expand_epilogue when
we are returning after EH is processed. Added a code in
ix86_expand_epilogue to adjust Shadow Stack pointer and to generate an
indirect jump instead of 'ret'. As sp register is used during this
adjustment thus the argument in pro_epilogue_adjust_stack is changed
to update cfa_reg based on whether control-flow instrumentation is set.
Without updating the cfa_reg field there is an assert later in dwarf2
pass related to mismatch the stack register and cfa_reg value.
gcc/
* config/i386/i386.c (ix86_expand_epilogue): Change simple
return to indirect jump for EH return if control-flow protection
is enabled. Change explicit 'false' argument in
pro_epilogue_adjust_stack with a value of flag_cf_protection.
* config/i386/i386.md (simple_return_indirect_internal): Remove
SImode restriction to support 64-bit.
libgcc/
* config/i386/linux-unwind.h: Include
config/i386/shadow-stack-unwind.h.
* config/i386/shadow-stack-unwind.h: New file.
* unwind-dw2.c: (uw_install_context): Add a frame parameter and
pass it to _Unwind_Frames_Extra.
* unwind-generic.h (_Unwind_Frames_Extra): New.
* unwind.inc (_Unwind_RaiseException_Phase2): Add frames_p
parameter. Add local variable frames to count number of frames.
(_Unwind_ForcedUnwind_Phase2): Likewise.
(_Unwind_RaiseException): Add local variable frames to count
number of frames, pass it to _Unwind_RaiseException_Phase2 and
uw_install_context.
(_Unwind_ForcedUnwind): Likewise.
(_Unwind_Resume): Likewise.
(_Unwind_Resume_or_Rethrow): Likewise.
From-SVN: r254876
libgcc/
* config/aarch64/aarch64-unwind.h: New file.
(DWARF_REGNUM_AARCH64_RA_STATE): Define.
(MD_POST_EXTRACT_ROOT_ADDR): New target marcro and define it on AArch64.
(MD_POST_EXTRACT_FRAME_ADDR): Likewise.
(MD_POST_FROB_EH_HANDLER_ADDR): Likewise.
(MD_FROB_UPDATE_CONTEXT): Define it on AArch64.
(aarch64_post_extract_frame_addr): New function.
(aarch64_post_frob_eh_handler_addr): New function.
(aarch64_frob_update_context): New function.
* config/aarch64/linux-unwind.h: Include aarch64-unwind.h
* config.host (aarch64*-*-elf, aarch64*-*-rtems*,
aarch64*-*-freebsd*):
Initialize md_unwind_header to include aarch64-unwind.h.
* unwind-dw2.c (struct _Unwind_Context): Define "RA_A_SIGNED_BIT".
(execute_cfa_program): Multiplex DW_CFA_GNU_window_save for
__aarch64__.
(uw_update_context): Honor MD_POST_EXTRACT_FRAME_ADDR.
(uw_init_context_1): Honor MD_POST_EXTRACT_ROOT_ADDR.
(uw_frob_return_addr): New function.
(uw_install_context): Use uw_frob_return_addr.
From-SVN: r244673
gcc/c-family:
* c-cppbuiltin.c (c_cpp_builtins): Also define
__LIBGCC_EH_TABLES_CAN_BE_READ_ONLY__,
__LIBGCC_EH_FRAME_SECTION_NAME__, __LIBGCC_JCR_SECTION_NAME__,
__LIBGCC_CTORS_SECTION_ASM_OP__, __LIBGCC_DTORS_SECTION_ASM_OP__,
__LIBGCC_TEXT_SECTION_ASM_OP__, __LIBGCC_INIT_SECTION_ASM_OP__,
__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__,
__LIBGCC_STACK_GROWS_DOWNWARD__,
__LIBGCC_DONT_USE_BUILTIN_SETJMP__,
__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__,
__LIBGCC_DWARF_FRAME_REGISTERS__,
__LIBGCC_EH_RETURN_STACKADJ_RTX__, __LIBGCC_JMP_BUF_SIZE__,
__LIBGCC_STACK_POINTER_REGNUM__ and
__LIBGCC_VTABLE_USES_DESCRIPTORS__ for -fbuilding-libgcc.
(builtin_define_with_value): Handle backslash-escaping in string
macro values.
libgcc:
* Makefile.in (CRTSTUFF_CFLAGS): Add -fbuilding-libgcc.
* config/aarch64/linux-unwind.h (STACK_POINTER_REGNUM): Change all
uses to __LIBGCC_STACK_POINTER_REGNUM__.
(DWARF_ALT_FRAME_RETURN_COLUMN): Change all uses to
__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/alpha/vms-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN):
Change use to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/cr16/unwind-cr16.c (STACK_GROWS_DOWNWARD): Change all
uses to __LIBGCC_STACK_GROWS_DOWNWARD__.
(DWARF_FRAME_REGISTERS): Change all uses to
__LIBGCC_DWARF_FRAME_REGISTERS__.
(EH_RETURN_STACKADJ_RTX): Change all uses to
__LIBGCC_EH_RETURN_STACKADJ_RTX__.
* config/cr16/unwind-dw2.h (DWARF_FRAME_REGISTERS): Change use to
__LIBGCC_DWARF_FRAME_REGISTERS__. Remove conditional definition.
* config/i386/cygming-crtbegin.c (EH_FRAME_SECTION_NAME): Change
use to __LIBGCC_EH_FRAME_SECTION_NAME__.
(JCR_SECTION_NAME): Change use to __LIBGCC_JCR_SECTION_NAME__.
* config/i386/cygming-crtend.c (EH_FRAME_SECTION_NAME): Change use
to __LIBGCC_EH_FRAME_SECTION_NAME__.
(JCR_SECTION_NAME): Change use to __LIBGCC_JCR_SECTION_NAME__
* config/mips/linux-unwind.h (STACK_POINTER_REGNUM): Change use to
__LIBGCC_STACK_POINTER_REGNUM__.
(DWARF_ALT_FRAME_RETURN_COLUMN): Change all uses to
__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/nios2/linux-unwind.h (STACK_POINTER_REGNUM): Change use
to __LIBGCC_STACK_POINTER_REGNUM__.
* config/pa/hpux-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN): Change
all uses to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/pa/linux-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN): Change
all uses to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/rs6000/aix-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN):
Change all uses to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
(STACK_POINTER_REGNUM): Change all uses to
__LIBGCC_STACK_POINTER_REGNUM__.
* config/rs6000/darwin-fallback.c (STACK_POINTER_REGNUM): Change
use to __LIBGCC_STACK_POINTER_REGNUM__.
* config/rs6000/linux-unwind.h (STACK_POINTER_REGNUM): Change all
uses to __LIBGCC_STACK_POINTER_REGNUM__.
* config/sparc/linux-unwind.h (DWARF_FRAME_REGISTERS): Change use
to __LIBGCC_DWARF_FRAME_REGISTERS__.
* config/sparc/sol2-unwind.h (DWARF_FRAME_REGISTERS): Change use
to __LIBGCC_DWARF_FRAME_REGISTERS__.
* config/tilepro/linux-unwind.h (STACK_POINTER_REGNUM): Change use
to __LIBGCC_STACK_POINTER_REGNUM__.
* config/xtensa/unwind-dw2-xtensa.h (DWARF_FRAME_REGISTERS):
Remove conditional definition.
* crtstuff.c (TEXT_SECTION_ASM_OP): Change all uses to
__LIBGCC_TEXT_SECTION_ASM_OP__.
(EH_FRAME_SECTION_NAME): Change all uses to
__LIBGCC_EH_FRAME_SECTION_NAME__.
(EH_TABLES_CAN_BE_READ_ONLY): Change all uses to
__LIBGCC_EH_TABLES_CAN_BE_READ_ONLY__.
(CTORS_SECTION_ASM_OP): Change all uses to
__LIBGCC_CTORS_SECTION_ASM_OP__.
(DTORS_SECTION_ASM_OP): Change all uses to
__LIBGCC_DTORS_SECTION_ASM_OP__.
(JCR_SECTION_NAME): Change all uses to
__LIBGCC_JCR_SECTION_NAME__.
(INIT_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_SECTION_ASM_OP__.
(INIT_ARRAY_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__.
* generic-morestack.c (STACK_GROWS_DOWNWARD): Change all uses to
__LIBGCC_STACK_GROWS_DOWNWARD__.
* libgcc2.c (INIT_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_SECTION_ASM_OP__.
(INIT_ARRAY_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__.
(EH_FRAME_SECTION_NAME): Change all uses to
__LIBGCC_EH_FRAME_SECTION_NAME__.
* libgcov-profiler.c (VTABLE_USES_DESCRIPTORS): Remove conditional
definitions. Change all uses to
__LIBGCC_VTABLE_USES_DESCRIPTORS__.
* unwind-dw2.c (STACK_GROWS_DOWNWARD): Change all uses to
__LIBGCC_STACK_GROWS_DOWNWARD__.
(DWARF_FRAME_REGISTERS): Change all uses to
__LIBGCC_DWARF_FRAME_REGISTERS__.
(EH_RETURN_STACKADJ_RTX): Change all uses to
__LIBGCC_EH_RETURN_STACKADJ_RTX__.
* unwind-dw2.h (DWARF_FRAME_REGISTERS): Remove conditional
definition. Change use to __LIBGCC_DWARF_FRAME_REGISTERS__.
* unwind-sjlj.c (DONT_USE_BUILTIN_SETJMP): Change all uses to
__LIBGCC_DONT_USE_BUILTIN_SETJMP__.
(JMP_BUF_SIZE): Change use to __LIBGCC_JMP_BUF_SIZE__.
From-SVN: r214954
PR tree-optimization/53265
* common.opt (Waggressive-loop-optimizations): New option.
* tree-ssa-loop-niter.c: Include tree-pass.h.
(do_warn_aggressive_loop_optimizations): New function.
(record_estimate): Call it. Don't add !is_exit bounds to loop->bounds
if number_of_latch_executions returned constant.
(estimate_numbers_of_iterations_loop): Call number_of_latch_executions
early. If number_of_latch_executions returned constant, set
nb_iterations_upper_bound back to it.
* cfgloop.h (struct loop): Add warned_aggressive_loop_optimizations
field.
* Makefile.in (tree-ssa-loop-niter.o): Depend on $(TREE_PASS_H).
* doc/invoke.texi (-Wno-aggressive-loop-optimizations): Document.
* gcc.dg/pr53265.c: New test.
* gcc.dg/torture/pr49518.c: Add -Wno-aggressive-loop-optimizations
to dg-options.
* g++.dg/opt/longbranch2.C (EBCOTLut): Double sizes of a2 and a3
arrays.
* gcc.dg/tree-ssa/cunroll-10.c (main): Rename to foo. Add argument
n, use it as high bound instead of 4.
* unwind-dw2.c (execute_cfa_program): Avoid
-Waggressive-array-optimizations warnings for DW_CFA_GNU_window_save
on targets with DWARF_FRAME_REGISTERS < 32.
* testsuite/libmudflap.c/fail37-frag.c: Add optimization barrier.
From-SVN: r196650
