+2019-09-30 Richard Sandiford <richard.sandiford@arm.com>
+
+ * Makefile.in (OBJS): Add function-abi.o.
+ (GTFILES): Add function-abi.h.
+ * function-abi.cc: New file.
+ * function-abi.h: Likewise.
+ * emit-rtl.h (rtl_data::abi): New field.
+ * function.c: Include function-abi.h.
+ (prepare_function_start): Initialize crtl->abi.
+ * read-rtl-function.c: Include regs.h and function-abi.h.
+ (read_rtl_function_body): Initialize crtl->abi.
+ (read_rtl_function_body_from_file_range): Likewise.
+ * reginfo.c: Include function-abi.h.
+ (init_reg_sets_1): Initialize default_function_abi.
+ (globalize_reg): Call add_full_reg_clobber for each predefined ABI
+ when making a register global.
+ * target-globals.h (this_target_function_abi_info): Declare.
+ (target_globals::function_abi_info): New field.
+ (restore_target_globals): Copy it.
+ * target-globals.c: Include function-abi.h.
+ (default_target_globals): Initialize the function_abi_info field.
+ (target_globals): Allocate it.
+ (save_target_globals): Free it.
+
2019-09-30 Nick Clifton <nickc@redhat.com>
PR target/85978
fold-const.o \
fold-const-call.o \
function.o \
+ function-abi.o \
function-tests.o \
fwprop.o \
gcc-rich-location.o \
$(srcdir)/libfuncs.h $(SYMTAB_H) \
$(srcdir)/real.h $(srcdir)/function.h $(srcdir)/insn-addr.h $(srcdir)/hwint.h \
$(srcdir)/fixed-value.h \
+ $(srcdir)/function-abi.h \
$(srcdir)/output.h $(srcdir)/cfgloop.h $(srcdir)/cfg.h $(srcdir)/profile-count.h \
$(srcdir)/cselib.h $(srcdir)/basic-block.h $(srcdir)/ipa-ref.h $(srcdir)/cgraph.h \
$(srcdir)/reload.h $(srcdir)/caller-save.c $(srcdir)/symtab.c \
class temp_slot;
typedef class temp_slot *temp_slot_p;
+class predefined_function_abi;
/* Information mainlined about RTL representation of incoming arguments. */
struct GTY(()) incoming_args {
struct function_subsections subsections;
struct rtl_eh eh;
+ /* The ABI of the function, i.e. the interface it presents to its callers.
+ This is the ABI that should be queried to see which registers the
+ function needs to save before it uses them.
+
+ Other functions (including those called by this function) might use
+ different ABIs. */
+ const predefined_function_abi *GTY((skip)) abi;
+
/* For function.c */
/* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
--- /dev/null
+/* Information about fuunction binary interfaces.
+ Copyright (C) 2019 Free Software Foundation, Inc.
+
+This file is part of GCC
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "backend.h"
+#include "target.h"
+#include "rtl.h"
+#include "tree.h"
+#include "regs.h"
+#include "function-abi.h"
+#include "varasm.h"
+#include "cgraph.h"
+
+target_function_abi_info default_target_function_abi_info;
+#if SWITCHABLE_TARGET
+target_function_abi_info *this_target_function_abi_info
+ = &default_target_function_abi_info;
+#endif
+
+/* Initialize a predefined function ABI with the given values of
+ ID and FULL_REG_CLOBBERS. */
+
+void
+predefined_function_abi::initialize (unsigned int id,
+ const_hard_reg_set full_reg_clobbers)
+{
+ m_id = id;
+ m_initialized = true;
+ m_full_reg_clobbers = full_reg_clobbers;
+
+ /* Set up the value of m_full_and_partial_reg_clobbers.
+
+ If the ABI specifies that part of a hard register R is call-clobbered,
+ we should be able to find a single-register mode M for which
+ targetm.hard_regno_call_part_clobbered (NULL, R, M) is true.
+ In other words, it shouldn't be the case that R can hold all
+ single-register modes across a call, but can't hold part of
+ a multi-register mode.
+
+ If that assumption doesn't hold for a future target, we would need
+ to change the interface of TARGET_HARD_REGNO_CALL_PART_CLOBBERED so
+ that it tells us which registers in a multi-register value are
+ actually clobbered. */
+ m_full_and_partial_reg_clobbers = full_reg_clobbers;
+ for (unsigned int i = 0; i < NUM_MACHINE_MODES; ++i)
+ {
+ machine_mode mode = (machine_mode) i;
+ for (unsigned int regno = 0; regno < FIRST_PSEUDO_REGISTER; ++regno)
+ if (targetm.hard_regno_mode_ok (regno, mode)
+ && hard_regno_nregs (regno, mode) == 1
+ && targetm.hard_regno_call_part_clobbered (NULL, regno, mode))
+ SET_HARD_REG_BIT (m_full_and_partial_reg_clobbers, regno);
+ }
+
+ /* For each mode MODE, work out which registers are unable to hold
+ any part of a MODE value across a call, i.e. those for which no
+ overlapping call-preserved (reg:MODE REGNO) exists.
+
+ We assume that this can be flipped around to say that a call
+ preserves (reg:MODE REGNO) unless the register overlaps this set.
+ The usual reason for this being true is that if (reg:MODE REGNO)
+ contains a part-clobbered register, that register would be
+ part-clobbered regardless of which part of MODE it holds.
+ For example, if (reg:M 2) occupies two registers and if the
+ register 3 portion of it is part-clobbered, (reg:M 3) is usually
+ either invalid or also part-clobbered. */
+ for (unsigned int i = 0; i < NUM_MACHINE_MODES; ++i)
+ {
+ machine_mode mode = (machine_mode) i;
+ m_mode_clobbers[i] = m_full_and_partial_reg_clobbers;
+ for (unsigned int regno = 0; regno < FIRST_PSEUDO_REGISTER; ++regno)
+ if (targetm.hard_regno_mode_ok (regno, mode)
+ && !overlaps_hard_reg_set_p (m_full_reg_clobbers, mode, regno)
+ && !targetm.hard_regno_call_part_clobbered (NULL, regno, mode))
+ remove_from_hard_reg_set (&m_mode_clobbers[i], mode, regno);
+ }
+
+ /* Check that the assumptions above actually hold, i.e. that testing
+ for single-register modes makes sense, and that overlap tests for
+ mode_clobbers work as expected. */
+ if (flag_checking)
+ for (unsigned int i = 0; i < NUM_MACHINE_MODES; ++i)
+ {
+ machine_mode mode = (machine_mode) i;
+ const_hard_reg_set all_clobbers = m_full_and_partial_reg_clobbers;
+ for (unsigned int regno = 0; regno < FIRST_PSEUDO_REGISTER; ++regno)
+ if (targetm.hard_regno_mode_ok (regno, mode)
+ && !overlaps_hard_reg_set_p (m_full_reg_clobbers, mode, regno)
+ && targetm.hard_regno_call_part_clobbered (NULL, regno, mode))
+ gcc_assert (overlaps_hard_reg_set_p (all_clobbers, mode, regno)
+ && overlaps_hard_reg_set_p (m_mode_clobbers[i],
+ mode, regno));
+ }
+}
+
+/* If the ABI has been initialized, add REGNO to the set of registers
+ that can be completely altered by a call. */
+
+void
+predefined_function_abi::add_full_reg_clobber (unsigned int regno)
+{
+ if (!m_initialized)
+ return;
+
+ SET_HARD_REG_BIT (m_full_reg_clobbers, regno);
+ SET_HARD_REG_BIT (m_full_and_partial_reg_clobbers, regno);
+ for (unsigned int i = 0; i < NUM_MACHINE_MODES; ++i)
+ SET_HARD_REG_BIT (m_mode_clobbers[i], regno);
+}
+
+/* Return the predefined ABI used by functions with type TYPE. */
+
+const predefined_function_abi &
+fntype_abi (const_tree type)
+{
+ gcc_assert (FUNC_OR_METHOD_TYPE_P (type));
+ return default_function_abi;
+}
+
+/* Return the ABI of function decl FNDECL. */
+
+function_abi
+fndecl_abi (const_tree fndecl)
+{
+ gcc_assert (TREE_CODE (fndecl) == FUNCTION_DECL);
+ return fntype_abi (TREE_TYPE (fndecl));
+}
--- /dev/null
+/* Information about fuunction binary interfaces.
+ Copyright (C) 2019 Free Software Foundation, Inc.
+
+This file is part of GCC
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#ifndef GCC_FUNCTION_ABI_H
+#define GCC_FUNCTION_ABI_H
+
+/* Most targets use the same ABI for all functions in a translation
+ unit, but some targets support interoperability between several ABIs.
+ Each such ABI has a unique 0-based identifier, with 0 always being
+ the default choice of ABI.
+
+ NUM_ABI_IDS is the maximum number of such ABIs that GCC can handle at once.
+ A bitfield with this number of bits can represent any combinaion of the
+ supported ABIs. */
+const size_t NUM_ABI_IDS = 8;
+
+/* Information about one of the target's predefined ABIs. */
+class predefined_function_abi
+{
+public:
+ /* A target-specific identifier for this ABI. The value must be in
+ the range [0, NUM_ABI_IDS - 1]. */
+ unsigned int id () const { return m_id; }
+
+ /* True if this ABI has been initialized. */
+ bool initialized_p () const { return m_initialized; }
+
+ /* Return true if a function call is allowed to alter every bit of
+ register REGNO, so that the register contains an arbitrary value
+ on return. If so, the register cannot hold any part of a value
+ that is live across a call. */
+ bool
+ clobbers_full_reg_p (unsigned int regno) const
+ {
+ return TEST_HARD_REG_BIT (m_full_reg_clobbers, regno);
+ }
+
+ /* Return true if a function call is allowed to alter some or all bits
+ of register REGNO.
+
+ This is true whenever clobbers_full_reg_p (REGNO) is true. It is
+ also true if, for example, the ABI says that a call must preserve the
+ low 32 or 64 bits of REGNO, but can clobber the upper bits of REGNO.
+ In the latter case, it is possible for REGNO to hold values that
+ are live across a call, provided that the value occupies only the
+ call-preserved part of the register. */
+ bool
+ clobbers_at_least_part_of_reg_p (unsigned int regno) const
+ {
+ return TEST_HARD_REG_BIT (m_full_and_partial_reg_clobbers, regno);
+ }
+
+ /* Return true if a function call is allowed to clobber at least part
+ of (reg:MODE REGNO). If so, it is not possible for the register
+ as a whole to be live across a call. */
+ bool
+ clobbers_reg_p (machine_mode mode, unsigned int regno) const
+ {
+ return overlaps_hard_reg_set_p (m_mode_clobbers[mode], mode, regno);
+ }
+
+ /* Return the set of registers that a function call is allowed to
+ alter completely, so that the registers contain arbitrary values
+ on return. This doesn't include registers that a call can only
+ partly clobber (as per TARGET_HARD_REGNO_CALL_PART_CLOBBERED).
+
+ These registers cannot hold any part of a value that is live across
+ a call. */
+ HARD_REG_SET full_reg_clobbers () const { return m_full_reg_clobbers; }
+
+ /* Return the set of registers that a function call is allowed to alter
+ to some degree. For example, if an ABI says that a call must preserve
+ the low 32 or 64 bits of a register R, but can clobber the upper bits
+ of R, R would be in this set but not in full_reg_clobbers ().
+
+ This set is a superset of full_reg_clobbers (). It is possible for a
+ register in full_and_partial_reg_clobbers () & ~full_reg_clobbers ()
+ to contain values that are live across a call, provided that the live
+ value only occupies the call-preserved part of the register. */
+ HARD_REG_SET
+ full_and_partial_reg_clobbers () const
+ {
+ return m_full_and_partial_reg_clobbers;
+ }
+
+ /* Return the set of registers that cannot be used to hold a value of
+ mode MODE across a function call. That is:
+
+ (reg:REGNO MODE)
+
+ might be clobbered by a call whenever:
+
+ overlaps_hard_reg_set (mode_clobbers (MODE), MODE, REGNO)
+
+ In allocation terms, the registers in the returned set conflict
+ with any value of mode MODE that is live across a call. */
+ HARD_REG_SET
+ mode_clobbers (machine_mode mode) const
+ {
+ return m_mode_clobbers[mode];
+ }
+
+ void initialize (unsigned int, const_hard_reg_set);
+ void add_full_reg_clobber (unsigned int);
+
+private:
+ unsigned int m_id : NUM_ABI_IDS;
+ unsigned int m_initialized : 1;
+ HARD_REG_SET m_full_reg_clobbers;
+ HARD_REG_SET m_full_and_partial_reg_clobbers;
+ HARD_REG_SET m_mode_clobbers[NUM_MACHINE_MODES];
+};
+
+/* Describes either a predefined ABI or the ABI of a particular function.
+ In the latter case, the ABI might make use of extra function-specific
+ information, such as for -fipa-ra. */
+class function_abi
+{
+public:
+ /* Initialize the structure for a general function with the given ABI. */
+ function_abi (const predefined_function_abi &base_abi)
+ : m_base_abi (&base_abi),
+ m_mask (base_abi.full_and_partial_reg_clobbers ()) {}
+
+ /* Initialize the structure for a function that has the given ABI and
+ that is known not to clobber registers outside MASK. */
+ function_abi (const predefined_function_abi &base_abi,
+ const_hard_reg_set mask)
+ : m_base_abi (&base_abi), m_mask (mask) {}
+
+ /* The predefined ABI from which this ABI is derived. */
+ const predefined_function_abi &base_abi () const { return *m_base_abi; }
+
+ /* The target-specific identifier of the predefined ABI. */
+ unsigned int id () const { return m_base_abi->id (); }
+
+ /* See the corresponding predefined_function_abi functions for
+ details about the following functions. */
+
+ HARD_REG_SET
+ full_reg_clobbers () const
+ {
+ return m_mask & m_base_abi->full_reg_clobbers ();
+ }
+
+ HARD_REG_SET
+ full_and_partial_reg_clobbers () const
+ {
+ return m_mask & m_base_abi->full_and_partial_reg_clobbers ();
+ }
+
+ HARD_REG_SET
+ mode_clobbers (machine_mode mode) const
+ {
+ return m_mask & m_base_abi->mode_clobbers (mode);
+ }
+
+ bool
+ clobbers_full_reg_p (unsigned int regno) const
+ {
+ return (TEST_HARD_REG_BIT (m_mask, regno)
+ & m_base_abi->clobbers_full_reg_p (regno));
+ }
+
+ bool
+ clobbers_at_least_part_of_reg_p (unsigned int regno) const
+ {
+ return (TEST_HARD_REG_BIT (m_mask, regno)
+ & m_base_abi->clobbers_at_least_part_of_reg_p (regno));
+ }
+
+ bool
+ clobbers_reg_p (machine_mode mode, unsigned int regno) const
+ {
+ return overlaps_hard_reg_set_p (mode_clobbers (mode), mode, regno);
+ }
+
+ bool
+ operator== (const function_abi &other) const
+ {
+ return m_base_abi == other.m_base_abi && m_mask == other.m_mask;
+ }
+
+ bool
+ operator!= (const function_abi &other) const
+ {
+ return !operator== (other);
+ }
+
+protected:
+ const predefined_function_abi *m_base_abi;
+ HARD_REG_SET m_mask;
+};
+
+struct target_function_abi_info
+{
+ /* An array of all the target ABIs that are available in this
+ translation unit. Not all entries are used for all targets,
+ but the structures are relatively small, and using a fixed-size
+ array avoids extra indirection.
+
+ There are various ways of getting an ABI descriptor:
+
+ * fndecl_abi (FNDECL) is the ABI of function FNDECL.
+
+ * fntype_abi (FNTYPE) is the ABI of a function with type FNTYPE.
+
+ * crtl->abi is the ABI of the function that we are currently
+ compiling to rtl.
+
+ * eh_edge_abi is the "ABI" used when taking an EH edge from an
+ exception-throwing statement to an exception handler. Catching
+ exceptions from calls can be treated as an abnormal return from
+ those calls, and this ABI therefore describes the ABI of functions
+ on such an abnormal return. Statements that throw non-call
+ exceptions can be treated as being implicitly wrapped in a call
+ that has such an abnormal return.
+
+ At present, no target needs to support more than one EH ABI.
+
+ * function_abis[N] is the ABI with identifier N. This can be useful
+ when referring back to ABIs that have been collected by number in
+ a bitmask, such as after walking function calls in a particular
+ region of code.
+
+ * default_function_abi refers specifically to the target's default
+ choice of ABI, regardless of which (if any) functions actually
+ use it. This ABI and data derived from it do *not* provide
+ globally conservatively-correct information, so it is only
+ useful in very specific circumstances. */
+ predefined_function_abi x_function_abis[NUM_ABI_IDS];
+};
+
+extern target_function_abi_info default_target_function_abi_info;
+#if SWITCHABLE_TARGET
+extern target_function_abi_info *this_target_function_abi_info;
+#else
+#define this_target_function_abi_info (&default_target_function_abi_info)
+#endif
+
+/* See the comment above x_function_abis for when these macros should be used.
+ At present, eh_edge_abi is always the default ABI, but that could change
+ in future if a target needs it to. */
+#define function_abis \
+ (this_target_function_abi_info->x_function_abis)
+#define default_function_abi \
+ (this_target_function_abi_info->x_function_abis[0])
+#define eh_edge_abi default_function_abi
+
+extern const predefined_function_abi &fntype_abi (const_tree);
+extern function_abi fndecl_abi (const_tree);
+
+#endif
#include "attribs.h"
#include "gimple.h"
#include "options.h"
+#include "function-abi.h"
/* So we can assign to cfun in this file. */
#undef cfun
prepare_function_start (void)
{
gcc_assert (!get_last_insn ());
+
+ if (in_dummy_function)
+ crtl->abi = &default_function_abi;
+ else
+ crtl->abi = &fndecl_abi (cfun->decl).base_abi ();
+
init_temp_slots ();
init_emit ();
init_varasm_status ();
#include "read-rtl-function.h"
#include "selftest.h"
#include "selftest-rtl.h"
+#include "regs.h"
+#include "function-abi.h"
/* Forward decls. */
class function_reader;
read_rtl_function_body (const char *path)
{
initialize_rtl ();
+ crtl->abi = &default_function_abi;
init_emit ();
init_varasm_status ();
}
initialize_rtl ();
+ crtl->abi = &fndecl_abi (cfun->decl).base_abi ();
init_emit ();
init_varasm_status ();
#include "reload.h"
#include "output.h"
#include "tree-pass.h"
+#include "function-abi.h"
/* Maximum register number used in this function, plus one. */
}
}
}
+
+ default_function_abi.initialize (0, regs_invalidated_by_call);
}
/* Compute the table of register modes.
appropriate regs_invalidated_by_call bit, even if it's already
set in fixed_regs. */
if (i != STACK_POINTER_REGNUM)
- SET_HARD_REG_BIT (regs_invalidated_by_call, i);
+ {
+ SET_HARD_REG_BIT (regs_invalidated_by_call, i);
+ for (unsigned int i = 0; i < NUM_ABI_IDS; ++i)
+ function_abis[i].add_full_reg_clobber (i);
+ }
/* If already fixed, nothing else to do. */
if (fixed_regs[i])
#include "gcse.h"
#include "bb-reorder.h"
#include "lower-subreg.h"
+#include "function-abi.h"
#if SWITCHABLE_TARGET
class target_globals default_target_globals = {
&default_target_rtl,
&default_target_recog,
&default_target_hard_regs,
+ &default_target_function_abi_info,
&default_target_reload,
&default_target_expmed,
&default_target_optabs,
g->rtl = ggc_cleared_alloc<target_rtl> ();
g->recog = XCNEW (struct target_recog);
g->hard_regs = XCNEW (struct target_hard_regs);
+ g->function_abi_info = XCNEW (struct target_function_abi_info);
g->reload = XCNEW (struct target_reload);
g->expmed = XCNEW (struct target_expmed);
g->optabs = XCNEW (struct target_optabs);
XDELETE (regs);
XDELETE (recog);
XDELETE (hard_regs);
+ XDELETE (function_abi_info);
XDELETE (reload);
XDELETE (expmed);
XDELETE (optabs);
extern struct target_rtl *this_target_rtl;
extern struct target_recog *this_target_recog;
extern struct target_hard_regs *this_target_hard_regs;
+extern struct target_function_abi_info *this_target_function_abi_info;
extern struct target_reload *this_target_reload;
extern struct target_expmed *this_target_expmed;
extern struct target_optabs *this_target_optabs;
struct target_rtl *rtl;
struct target_recog *GTY((skip)) recog;
struct target_hard_regs *GTY((skip)) hard_regs;
+ struct target_function_abi_info *GTY((skip)) function_abi_info;
struct target_reload *GTY((skip)) reload;
struct target_expmed *GTY((skip)) expmed;
struct target_optabs *GTY((skip)) optabs;
this_target_rtl = g->rtl;
this_target_recog = g->recog;
this_target_hard_regs = g->hard_regs;
+ this_target_function_abi_info = g->function_abi_info;
this_target_reload = g->reload;
this_target_expmed = g->expmed;
this_target_optabs = g->optabs;
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