This patch fixes a rare but serious bug. The Go garbage
collector only examines Go stacks. When Go code calls a
function that is not written in Go, it first calls
syscall.Entersyscall. Entersyscall records the position of
the Go stack pointer and saves a copy of all the registers.
If the garbage collector runs while the thread is executing
the non-Go code, the garbage collector fetches the stack
pointer and registers from the saved location.
Entersyscall saves the registers using the getcontext
function. Unfortunately I didn't consider the possibility
that Entersyscall might itself change a register before
calling getcontext. This only matters for callee-saved
registers, as caller-saved registers would be visible on the
saved stack. And it only matters if Entersyscall is compiled
to save and modify a callee-saved register before it calls
getcontext. And it only matters if a garbage collection
occurs while the non-Go code is executing. And it only
matters if the only copy of a valid Go pointer happens to be
in the callee-saved register when Entersyscall is called.
When all those conditions are true, the Go pointer might get
collected incorrectly, leading to memory corruption.
This patch tries to avoid the problem by splitting
Entersyscall into two functions. The first is a simple
function that just calls getcontext and then calls the rest of
Entersyscall. This should fix the problem, provided the
simple Entersyscall function does not itself modify any
callee-saved registers before calling getcontext. That seems
to be true on the systems I checked. But since the argument
to getcontext is an offset from a TLS variable, it won't be
true on a system which needs to save callee-saved registers in
order to get the address of a TLS variable. I don't know why
any system would work that way, but I don't know how to rule
it out. I think that on any such system this will have to be
implemented in assembler. I can't put the ucontext_t
structure on the stack, because this function can not split
stacks, and the ucontext_t structure is large enough that it
could cause a stack overflow.
From-SVN: r208390
2014-03-06 Paul Thomas <pault@gcc.gnu.org>
Janus Weil <janus@gcc.gnu.org>
PR fortran/51976
* gfortran.h (symbol_attribute): Add deferred_parameter attribute.
* primary.c (build_actual_constructor): It is not an error if
a missing component has the deferred_parameter attribute;
equally, if one is given a value, it is an error.
* resolve.c (resolve_fl_derived0): Remove error for deferred
character length components. Add the hidden string length
field to the structure. Give it the deferred_parameter
attribute.
* trans-array.c (duplicate_allocatable): Add a strlen field
which is used as the element size if it is non-null.
(gfc_duplicate_allocatable, gfc_copy_allocatable_data): Pass a
NULL to the new argument in duplicate_allocatable.
(structure_alloc_comps): Set the hidden string length as
appropriate. Use it in calls to duplicate_allocatable.
(gfc_alloc_allocatable_for_assignment): When a deferred length
backend declaration is variable, use that; otherwise use the
string length from the expression evaluation.
* trans-expr.c (gfc_conv_component_ref): If this is a deferred
character length component, the string length should have the
value of the hidden string length field.
(gfc_trans_subcomponent_assign): Set the hidden string length
field for deferred character length components. Allocate the
necessary memory for the string.
(alloc_scalar_allocatable_for_assignment): Same change as in
gfc_alloc_allocatable_for_assignment above.
* trans-stmt.c (gfc_trans_allocate): Likewise.
* trans-intrinsic (size_of_string_in_bytes): Make non-static.
* trans-types.c (gfc_get_derived_type): Set the tree type for
a deferred character length component.
* trans.c (gfc_deferred_strlen): New function.
* trans.h (size_of_string_in_bytes,gfc_deferred_strlen): New prototypes.
2014-03-06 Paul Thomas <pault@gcc.gnu.org>
Janus Weil <janus@gcc.gnu.org>
PR fortran/51976
* gfortran.dg/deferred_type_component_1.f90 : New test.
* gfortran.dg/deferred_type_component_2.f90 : New test.
Co-Authored-By: Janus Weil <janus@gcc.gnu.org>
From-SVN: r208386
2014-03-06 Matthias Klose <doko@ubuntu.com>
* Makefile.in (s-mlib): Only pass MULTIARCH_DIRNAME if
MULTILIB_OSDIRNAMES is not defined.
From-SVN: r208383
2014-03-06 Richard Biener <rguenther@suse.de>
PR middle-end/60445
PR lto/60424
PR lto/60427
Revert
2014-03-04 Paulo Matos <paulo@matos-sorge.com>
* tree-streamer.c (record_common_node): Assert we don't record
nodes with type double.
(preload_common_node): Skip type double, complex double and
double pointer since it is now frontend dependent due to
fshort-double option.
* gcc.dg/lto/pr55113_0.c: New testcase.
From-SVN: r208379
2014-03-06 Richard Biener <rguenther@suse.de>
* gcc.c (PLUGIN_COND): Always enable unless -fno-use-linker-plugin
or -fno-lto is specified and the linker has full plugin support.
* collect2.c (lto_mode): Default to LTO_MODE_WHOPR if LTO is
enabled.
(main): Remove -flto processing, adjust lto_mode using
use_plugin late.
* lto-wrapper.c (merge_and_complain): Merge compile-time
optimization levels.
(run_gcc): And pass it through to the link options.
From-SVN: r208375
PR testsuite/59308
* gcc.dg/pr46309.c: Don't compile on logical_op_short_circuit targets
other than mips/avr. Use -mbranch-cost=2 even for i?86/x86_64.
* gcc.dg/tree-ssa/reassoc-32.c: Use -mbranch-cost=2 even for
s390*/i?86/x86_64.
* gcc.dg/tree-ssa/reassoc-33.c: Likewise.
* gcc.dg/tree-ssa/reassoc-34.c: Likewise.
* gcc.dg/tree-ssa/reassoc-35.c: Likewise.
* gcc.dg/tree-ssa/reassoc-36.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-1.c: Don't compile on
logical_op_short_circuit targets other than avr. Use -mbranch-cost=2
even for mips*/s390*/i?86/x86_64.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-2.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-3.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-4.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-5.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-6.c: Likewise.
From-SVN: r208354
PR c++/60361
* parser.c (cp_parser_template_id): Don't set up a CPP_TEMPLATE_ID
if re-parsing might succeed.
* semantics.c (finish_id_expression): Use of a parameter outside
the function body is a parse error.
From-SVN: r208351
PR lto/60404
* cfgexpand.c (expand_used_vars): Do not assume all SSA_NAMEs
of PARM/RESULT_DECLs must be coalesced with optimize && in_lto_p.
* tree-ssa-coalesce.c (coalesce_ssa_name): Use MUST_COALESCE_COST - 1
cost for in_lto_p.
* gcc.dg/lto/pr60404_0.c: New test.
* gcc.dg/lto/pr60404_1.c: New file.
* gcc.dg/lto/pr60404_2.c: New file.
From-SVN: r208340
2014-03-04 Paulo Matos <paulo@matos-sorge.com>
* tree-streamer.c (record_common_node): Assert we don't record
nodes with type double.
(preload_common_node): Skip type double, complex double and
double pointer since it is now frontend dependent due to
fshort-double option.
2014-03-04 Paulo Matos <paulo@matos-sorge.com>
* gcc.dg/lto/pr55113_0.c: New testcase.
From-SVN: r208312
2014-03-04 Richard Biener <rguenther@suse.de>
PR lto/60405
* lto-streamer-in.c (lto_read_body): Remove LTO bytecode version
check.
(lto_input_toplevel_asms): Likewise.
* lto-section-in.c (lto_get_section_data): Instead do it here
for every section.
From-SVN: r208311
2014-03-04 Richard Biener <rguenther@suse.de>
PR tree-optimization/60382
* tree-vect-loop.c (vect_is_simple_reduction_1): Do not consider
dead PHIs a reduction.
* gcc.dg/vect/pr60382.c: New testcase.
From-SVN: r208305
2014-03-03 Jerry DeLisle <jvdelisle@gcc.gnu>
PR libfortran/60148
* io/inquire.c (inquire_via_unit): In the case of
DELIM_UNSPECIFIED set inquire return string to "NONE".
* io/list_read.c (read_character): In the case of DELIM_NONE and
namelists, complete the character read using the namelist
variable length.
* io/open.c (new_unit): Don't set delim status to none if not
specified so that DELIM_UNSPECIFIED can be used later.
* io/transfer.c (data_transfer_init): For namelist I/O, if the
unit delim status is unspecified set the current status to quote.
Otherwise, set current status to the unit status.
* io/unit.c (get_internel_unit, init_unit): Remember to set
flags_delim initially to DELIM_UNSPECIFIED so defaults come out
correctly.
* io/write.c (write_character): Add a new function argument
"mode" to signify that raw output is to be used vs output with
delimiters. If the mode is set to DELIM (1) proceed with
delimiters. (list_formatted_write_scalar): Write the separator
only if a delimiter was previously specified. Update the call to
write_character with the mode argument given.
(namelist_write_newline): Use the mode argument. (nml_write_obj):
Use the mode argument. Remove use of tmp_delim. Write the
semi-colon or comma correctly only when needed with using
delimiters. Cleanup whitespace.
(namelist_write): If delim is not specified in namelist I/O,
default to using quotes. Get rid of the tmp_delim variable and
use the new mode argument in write_character.
From-SVN: r208302
* go-gcc.cc (Gcc_backend::immutable_struct): If IS_COMMON, set
DECL_WEAK.
(GCC_backend::immutable_struct_set_init): If IS_COMMON, clear
DECL_WEAK.
From-SVN: r208301
2014-03-03 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
* config/rs6000/rs6000.c (rs6000_preferred_reload_class): Disallow
reload of PLUS rtx's outside of GENERAL_REGS or BASE_REGS; relax
constraint on constants to permit them being loaded into
GENERAL_REGS or BASE_REGS.
From-SVN: r208287
