6791469314
2019-01-09 Sandra Loosemore <sandra@codesourcery.com> PR other/16615 [1/5] contrib/ * mklog: Mechanically replace "can not" with "cannot". gcc/ * Makefile.in: Mechanically replace "can not" with "cannot". * alias.c: Likewise. * builtins.c: Likewise. * calls.c: Likewise. * cgraph.c: Likewise. * cgraph.h: Likewise. * cgraphclones.c: Likewise. * cgraphunit.c: Likewise. * combine-stack-adj.c: Likewise. * combine.c: Likewise. * common/config/i386/i386-common.c: Likewise. * config/aarch64/aarch64.c: Likewise. * config/alpha/sync.md: Likewise. * config/arc/arc.c: Likewise. * config/arc/predicates.md: Likewise. * config/arm/arm-c.c: Likewise. * config/arm/arm.c: Likewise. * config/arm/arm.h: Likewise. * config/arm/arm.md: Likewise. * config/arm/cortex-r4f.md: Likewise. * config/csky/csky.c: Likewise. * config/csky/csky.h: Likewise. * config/darwin-f.c: Likewise. * config/epiphany/epiphany.md: Likewise. * config/i386/i386.c: Likewise. * config/i386/sol2.h: Likewise. * config/m68k/m68k.c: Likewise. * config/mcore/mcore.h: Likewise. * config/microblaze/microblaze.md: Likewise. * config/mips/20kc.md: Likewise. * config/mips/sb1.md: Likewise. * config/nds32/nds32.c: Likewise. * config/nds32/predicates.md: Likewise. * config/pa/pa.c: Likewise. * config/rs6000/e300c2c3.md: Likewise. * config/rs6000/rs6000.c: Likewise. * config/s390/s390.h: Likewise. * config/sh/sh.c: Likewise. * config/sh/sh.md: Likewise. * config/spu/vmx2spu.h: Likewise. * cprop.c: Likewise. * dbxout.c: Likewise. * df-scan.c: Likewise. * doc/cfg.texi: Likewise. * doc/extend.texi: Likewise. * doc/fragments.texi: Likewise. * doc/gty.texi: Likewise. * doc/invoke.texi: Likewise. * doc/lto.texi: Likewise. * doc/md.texi: Likewise. * doc/objc.texi: Likewise. * doc/rtl.texi: Likewise. * doc/tm.texi: Likewise. * dse.c: Likewise. * emit-rtl.c: Likewise. * emit-rtl.h: Likewise. * except.c: Likewise. * expmed.c: Likewise. * expr.c: Likewise. * fold-const.c: Likewise. * genautomata.c: Likewise. * gimple-fold.c: Likewise. * hard-reg-set.h: Likewise. * ifcvt.c: Likewise. * ipa-comdats.c: Likewise. * ipa-cp.c: Likewise. * ipa-devirt.c: Likewise. * ipa-fnsummary.c: Likewise. * ipa-icf.c: Likewise. * ipa-inline-transform.c: Likewise. * ipa-inline.c: Likewise. * ipa-polymorphic-call.c: Likewise. * ipa-profile.c: Likewise. * ipa-prop.c: Likewise. * ipa-pure-const.c: Likewise. * ipa-reference.c: Likewise. * ipa-split.c: Likewise. * ipa-visibility.c: Likewise. * ipa.c: Likewise. * ira-build.c: Likewise. * ira-color.c: Likewise. * ira-conflicts.c: Likewise. * ira-costs.c: Likewise. * ira-int.h: Likewise. * ira-lives.c: Likewise. * ira.c: Likewise. * ira.h: Likewise. * loop-invariant.c: Likewise. * loop-unroll.c: Likewise. * lower-subreg.c: Likewise. * lra-assigns.c: Likewise. * lra-constraints.c: Likewise. * lra-eliminations.c: Likewise. * lra-lives.c: Likewise. * lra-remat.c: Likewise. * lra-spills.c: Likewise. * lra.c: Likewise. * lto-cgraph.c: Likewise. * lto-streamer-out.c: Likewise. * postreload-gcse.c: Likewise. * predict.c: Likewise. * profile-count.h: Likewise. * profile.c: Likewise. * recog.c: Likewise. * ree.c: Likewise. * reload.c: Likewise. * reload1.c: Likewise. * reorg.c: Likewise. * resource.c: Likewise. * rtl.def: Likewise. * rtl.h: Likewise. * rtlanal.c: Likewise. * sched-deps.c: Likewise. * sched-ebb.c: Likewise. * sched-rgn.c: Likewise. * sel-sched-ir.c: Likewise. * sel-sched.c: Likewise. * shrink-wrap.c: Likewise. * simplify-rtx.c: Likewise. * symtab.c: Likewise. * target.def: Likewise. * toplev.c: Likewise. * tree-call-cdce.c: Likewise. * tree-cfg.c: Likewise. * tree-complex.c: Likewise. * tree-core.h: Likewise. * tree-eh.c: Likewise. * tree-inline.c: Likewise. * tree-loop-distribution.c: Likewise. * tree-nrv.c: Likewise. * tree-profile.c: Likewise. * tree-sra.c: Likewise. * tree-ssa-alias.c: Likewise. * tree-ssa-dce.c: Likewise. * tree-ssa-dom.c: Likewise. * tree-ssa-forwprop.c: Likewise. * tree-ssa-loop-im.c: Likewise. * tree-ssa-loop-ivcanon.c: Likewise. * tree-ssa-loop-ivopts.c: Likewise. * tree-ssa-loop-niter.c: Likewise. * tree-ssa-phionlycprop.c: Likewise. * tree-ssa-phiopt.c: Likewise. * tree-ssa-propagate.c: Likewise. * tree-ssa-threadedge.c: Likewise. * tree-ssa-threadupdate.c: Likewise. * tree-ssa-uninit.c: Likewise. * tree-ssanames.c: Likewise. * tree-streamer-out.c: Likewise. * tree.c: Likewise. * tree.h: Likewise. * vr-values.c: Likewise. gcc/ada/ * exp_ch9.adb: Mechanically replace "can not" with "cannot". * libgnat/s-regpat.ads: Likewise. * par-ch4.adb: Likewise. * set_targ.adb: Likewise. * types.ads: Likewise. gcc/cp/ * cp-tree.h: Mechanically replace "can not" with "cannot". * parser.c: Likewise. * pt.c: Likewise. gcc/fortran/ * class.c: Mechanically replace "can not" with "cannot". * decl.c: Likewise. * expr.c: Likewise. * gfc-internals.texi: Likewise. * intrinsic.texi: Likewise. * invoke.texi: Likewise. * io.c: Likewise. * match.c: Likewise. * parse.c: Likewise. * primary.c: Likewise. * resolve.c: Likewise. * symbol.c: Likewise. * trans-array.c: Likewise. * trans-decl.c: Likewise. * trans-intrinsic.c: Likewise. * trans-stmt.c: Likewise. gcc/go/ * go-backend.c: Mechanically replace "can not" with "cannot". * go-gcc.cc: Likewise. gcc/lto/ * lto-partition.c: Mechanically replace "can not" with "cannot". * lto-symtab.c: Likewise. * lto.c: Likewise. gcc/objc/ * objc-act.c: Mechanically replace "can not" with "cannot". libbacktrace/ * backtrace.h: Mechanically replace "can not" with "cannot". libgcc/ * config/c6x/libunwind.S: Mechanically replace "can not" with "cannot". * config/tilepro/atomic.h: Likewise. * config/vxlib-tls.c: Likewise. * generic-morestack-thread.c: Likewise. * generic-morestack.c: Likewise. * mkmap-symver.awk: Likewise. libgfortran/ * caf/single.c: Mechanically replace "can not" with "cannot". * io/unit.c: Likewise. libobjc/ * class.c: Mechanically replace "can not" with "cannot". * objc/runtime.h: Likewise. * sendmsg.c: Likewise. liboffloadmic/ * include/coi/common/COIResult_common.h: Mechanically replace "can not" with "cannot". * include/coi/source/COIBuffer_source.h: Likewise. libstdc++-v3/ * include/ext/bitmap_allocator.h: Mechanically replace "can not" with "cannot". From-SVN: r267783
407 lines
12 KiB
C
407 lines
12 KiB
C
/* Language independent return value optimizations
|
|
Copyright (C) 2004-2019 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 "tree.h"
|
|
#include "gimple.h"
|
|
#include "tree-pass.h"
|
|
#include "ssa.h"
|
|
#include "tree-pretty-print.h"
|
|
#include "gimple-iterator.h"
|
|
#include "gimple-walk.h"
|
|
#include "internal-fn.h"
|
|
|
|
/* This file implements return value optimizations for functions which
|
|
return aggregate types.
|
|
|
|
Basically this pass searches the function for return statements which
|
|
return a local aggregate. When converted to RTL such statements will
|
|
generate a copy from the local aggregate to final return value destination
|
|
mandated by the target's ABI.
|
|
|
|
That copy can often be avoided by directly constructing the return value
|
|
into the final destination mandated by the target's ABI.
|
|
|
|
This is basically a generic equivalent to the C++ front-end's
|
|
Named Return Value optimization. */
|
|
|
|
struct nrv_data_t
|
|
{
|
|
/* This is the temporary (a VAR_DECL) which appears in all of
|
|
this function's RETURN_EXPR statements. */
|
|
tree var;
|
|
|
|
/* This is the function's RESULT_DECL. We will replace all occurrences
|
|
of VAR with RESULT_DECL when we apply this optimization. */
|
|
tree result;
|
|
int modified;
|
|
};
|
|
|
|
static tree finalize_nrv_r (tree *, int *, void *);
|
|
|
|
/* Callback for the tree walker.
|
|
|
|
If TP refers to a RETURN_EXPR, then set the expression being returned
|
|
to nrv_data->result.
|
|
|
|
If TP refers to nrv_data->var, then replace nrv_data->var with
|
|
nrv_data->result.
|
|
|
|
If we reach a node where we know all the subtrees are uninteresting,
|
|
then set *WALK_SUBTREES to zero. */
|
|
|
|
static tree
|
|
finalize_nrv_r (tree *tp, int *walk_subtrees, void *data)
|
|
{
|
|
struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
|
|
struct nrv_data_t *dp = (struct nrv_data_t *) wi->info;
|
|
|
|
/* No need to walk into types. */
|
|
if (TYPE_P (*tp))
|
|
*walk_subtrees = 0;
|
|
|
|
/* Otherwise replace all occurrences of VAR with RESULT. */
|
|
else if (*tp == dp->var)
|
|
{
|
|
*tp = dp->result;
|
|
dp->modified = 1;
|
|
}
|
|
|
|
/* Keep iterating. */
|
|
return NULL_TREE;
|
|
}
|
|
|
|
/* Main entry point for return value optimizations.
|
|
|
|
If this function always returns the same local variable, and that
|
|
local variable is an aggregate type, then replace the variable with
|
|
the function's DECL_RESULT.
|
|
|
|
This is the equivalent of the C++ named return value optimization
|
|
applied to optimized trees in a language independent form. If we
|
|
ever encounter languages which prevent this kind of optimization,
|
|
then we could either have the languages register the optimization or
|
|
we could change the gating function to check the current language. */
|
|
|
|
namespace {
|
|
|
|
const pass_data pass_data_nrv =
|
|
{
|
|
GIMPLE_PASS, /* type */
|
|
"nrv", /* name */
|
|
OPTGROUP_NONE, /* optinfo_flags */
|
|
TV_TREE_NRV, /* tv_id */
|
|
( PROP_ssa | PROP_cfg ), /* properties_required */
|
|
0, /* properties_provided */
|
|
0, /* properties_destroyed */
|
|
0, /* todo_flags_start */
|
|
0, /* todo_flags_finish */
|
|
};
|
|
|
|
class pass_nrv : public gimple_opt_pass
|
|
{
|
|
public:
|
|
pass_nrv (gcc::context *ctxt)
|
|
: gimple_opt_pass (pass_data_nrv, ctxt)
|
|
{}
|
|
|
|
/* opt_pass methods: */
|
|
virtual bool gate (function *) { return optimize > 0; }
|
|
|
|
virtual unsigned int execute (function *);
|
|
|
|
}; // class pass_nrv
|
|
|
|
unsigned int
|
|
pass_nrv::execute (function *fun)
|
|
{
|
|
tree result = DECL_RESULT (current_function_decl);
|
|
tree result_type = TREE_TYPE (result);
|
|
tree found = NULL;
|
|
basic_block bb;
|
|
gimple_stmt_iterator gsi;
|
|
struct nrv_data_t data;
|
|
|
|
/* If this function does not return an aggregate type in memory, then
|
|
there is nothing to do. */
|
|
if (!aggregate_value_p (result, current_function_decl))
|
|
return 0;
|
|
|
|
/* If a GIMPLE type is returned in memory, finalize_nrv_r might create
|
|
non-GIMPLE. */
|
|
if (is_gimple_reg_type (result_type))
|
|
return 0;
|
|
|
|
/* If the front end already did something like this, don't do it here. */
|
|
if (DECL_NAME (result))
|
|
return 0;
|
|
|
|
/* If the result has its address taken then it might be modified
|
|
by means not detected in the following loop. Bail out in this
|
|
case. */
|
|
if (TREE_ADDRESSABLE (result))
|
|
return 0;
|
|
|
|
/* Look through each block for assignments to the RESULT_DECL. */
|
|
FOR_EACH_BB_FN (bb, fun)
|
|
{
|
|
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
|
|
{
|
|
gimple *stmt = gsi_stmt (gsi);
|
|
tree ret_val;
|
|
|
|
if (greturn *return_stmt = dyn_cast <greturn *> (stmt))
|
|
{
|
|
/* In a function with an aggregate return value, the
|
|
gimplifier has changed all non-empty RETURN_EXPRs to
|
|
return the RESULT_DECL. */
|
|
ret_val = gimple_return_retval (return_stmt);
|
|
if (ret_val)
|
|
gcc_assert (ret_val == result);
|
|
}
|
|
else if (gimple_has_lhs (stmt)
|
|
&& gimple_get_lhs (stmt) == result)
|
|
{
|
|
tree rhs;
|
|
|
|
if (!gimple_assign_copy_p (stmt))
|
|
return 0;
|
|
|
|
rhs = gimple_assign_rhs1 (stmt);
|
|
|
|
/* Now verify that this return statement uses the same value
|
|
as any previously encountered return statement. */
|
|
if (found != NULL)
|
|
{
|
|
/* If we found a return statement using a different variable
|
|
than previous return statements, then we cannot perform
|
|
NRV optimizations. */
|
|
if (found != rhs)
|
|
return 0;
|
|
}
|
|
else
|
|
found = rhs;
|
|
|
|
/* The returned value must be a local automatic variable of the
|
|
same type and alignment as the function's result. */
|
|
if (!VAR_P (found)
|
|
|| TREE_THIS_VOLATILE (found)
|
|
|| !auto_var_in_fn_p (found, current_function_decl)
|
|
|| TREE_ADDRESSABLE (found)
|
|
|| DECL_ALIGN (found) > DECL_ALIGN (result)
|
|
|| !useless_type_conversion_p (result_type,
|
|
TREE_TYPE (found)))
|
|
return 0;
|
|
}
|
|
else if (gimple_has_lhs (stmt))
|
|
{
|
|
tree addr = get_base_address (gimple_get_lhs (stmt));
|
|
/* If there's any MODIFY of component of RESULT,
|
|
then bail out. */
|
|
if (addr && addr == result)
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!found)
|
|
return 0;
|
|
|
|
/* If dumping details, then note once and only the NRV replacement. */
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "NRV Replaced: ");
|
|
print_generic_expr (dump_file, found, dump_flags);
|
|
fprintf (dump_file, " with: ");
|
|
print_generic_expr (dump_file, result, dump_flags);
|
|
fprintf (dump_file, "\n");
|
|
}
|
|
|
|
/* At this point we know that all the return statements return the
|
|
same local which has suitable attributes for NRV. Copy debugging
|
|
information from FOUND to RESULT if it will be useful. But don't set
|
|
DECL_ABSTRACT_ORIGIN to point at another function. */
|
|
if (!DECL_IGNORED_P (found)
|
|
&& !(DECL_ABSTRACT_ORIGIN (found)
|
|
&& DECL_CONTEXT (DECL_ABSTRACT_ORIGIN (found)) != current_function_decl))
|
|
{
|
|
DECL_NAME (result) = DECL_NAME (found);
|
|
DECL_SOURCE_LOCATION (result) = DECL_SOURCE_LOCATION (found);
|
|
DECL_ABSTRACT_ORIGIN (result) = DECL_ABSTRACT_ORIGIN (found);
|
|
}
|
|
|
|
TREE_ADDRESSABLE (result) |= TREE_ADDRESSABLE (found);
|
|
|
|
/* Now walk through the function changing all references to VAR to be
|
|
RESULT. */
|
|
data.var = found;
|
|
data.result = result;
|
|
FOR_EACH_BB_FN (bb, fun)
|
|
{
|
|
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
|
|
{
|
|
gimple *stmt = gsi_stmt (gsi);
|
|
/* If this is a copy from VAR to RESULT, remove it. */
|
|
if (gimple_assign_copy_p (stmt)
|
|
&& gimple_assign_lhs (stmt) == result
|
|
&& gimple_assign_rhs1 (stmt) == found)
|
|
{
|
|
unlink_stmt_vdef (stmt);
|
|
gsi_remove (&gsi, true);
|
|
release_defs (stmt);
|
|
}
|
|
else
|
|
{
|
|
struct walk_stmt_info wi;
|
|
memset (&wi, 0, sizeof (wi));
|
|
wi.info = &data;
|
|
data.modified = 0;
|
|
walk_gimple_op (stmt, finalize_nrv_r, &wi);
|
|
if (data.modified)
|
|
update_stmt (stmt);
|
|
gsi_next (&gsi);
|
|
}
|
|
}
|
|
}
|
|
|
|
SET_DECL_VALUE_EXPR (found, result);
|
|
DECL_HAS_VALUE_EXPR_P (found) = 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
} // anon namespace
|
|
|
|
gimple_opt_pass *
|
|
make_pass_nrv (gcc::context *ctxt)
|
|
{
|
|
return new pass_nrv (ctxt);
|
|
}
|
|
|
|
/* Determine (pessimistically) whether DEST is available for NRV
|
|
optimization, where DEST is expected to be the LHS of a modify
|
|
expression where the RHS is a function returning an aggregate.
|
|
|
|
DEST is available if it is not clobbered or used by the call. */
|
|
|
|
static bool
|
|
dest_safe_for_nrv_p (gcall *call)
|
|
{
|
|
tree dest = gimple_call_lhs (call);
|
|
|
|
dest = get_base_address (dest);
|
|
if (! dest)
|
|
return false;
|
|
|
|
if (TREE_CODE (dest) == SSA_NAME)
|
|
return true;
|
|
|
|
if (call_may_clobber_ref_p (call, dest)
|
|
|| ref_maybe_used_by_stmt_p (call, dest))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/* Walk through the function looking for GIMPLE_ASSIGNs with calls that
|
|
return in memory on the RHS. For each of these, determine whether it is
|
|
safe to pass the address of the LHS as the return slot, and mark the
|
|
call appropriately if so.
|
|
|
|
The NRV shares the return slot with a local variable in the callee; this
|
|
optimization shares the return slot with the target of the call within
|
|
the caller. If the NRV is performed (which we can't know in general),
|
|
this optimization is safe if the address of the target has not
|
|
escaped prior to the call. If it has, modifications to the local
|
|
variable will produce visible changes elsewhere, as in PR c++/19317. */
|
|
|
|
namespace {
|
|
|
|
const pass_data pass_data_return_slot =
|
|
{
|
|
GIMPLE_PASS, /* type */
|
|
"retslot", /* name */
|
|
OPTGROUP_NONE, /* optinfo_flags */
|
|
TV_NONE, /* tv_id */
|
|
PROP_ssa, /* properties_required */
|
|
0, /* properties_provided */
|
|
0, /* properties_destroyed */
|
|
0, /* todo_flags_start */
|
|
0, /* todo_flags_finish */
|
|
};
|
|
|
|
class pass_return_slot : public gimple_opt_pass
|
|
{
|
|
public:
|
|
pass_return_slot (gcc::context *ctxt)
|
|
: gimple_opt_pass (pass_data_return_slot, ctxt)
|
|
{}
|
|
|
|
/* opt_pass methods: */
|
|
virtual unsigned int execute (function *);
|
|
|
|
}; // class pass_return_slot
|
|
|
|
unsigned int
|
|
pass_return_slot::execute (function *fun)
|
|
{
|
|
basic_block bb;
|
|
|
|
FOR_EACH_BB_FN (bb, fun)
|
|
{
|
|
gimple_stmt_iterator gsi;
|
|
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
|
|
{
|
|
gcall *stmt;
|
|
bool slot_opt_p;
|
|
|
|
stmt = dyn_cast <gcall *> (gsi_stmt (gsi));
|
|
if (stmt
|
|
&& gimple_call_lhs (stmt)
|
|
&& !gimple_call_return_slot_opt_p (stmt)
|
|
/* Ignore internal functions without direct optabs,
|
|
those are expanded specially and aggregate_value_p
|
|
on their result might result in undesirable warnings
|
|
with some backends. */
|
|
&& (!gimple_call_internal_p (stmt)
|
|
|| direct_internal_fn_p (gimple_call_internal_fn (stmt)))
|
|
&& aggregate_value_p (TREE_TYPE (gimple_call_lhs (stmt)),
|
|
gimple_call_fndecl (stmt)))
|
|
{
|
|
/* Check if the location being assigned to is
|
|
clobbered by the call. */
|
|
slot_opt_p = dest_safe_for_nrv_p (stmt);
|
|
gimple_call_set_return_slot_opt (stmt, slot_opt_p);
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
} // anon namespace
|
|
|
|
gimple_opt_pass *
|
|
make_pass_return_slot (gcc::context *ctxt)
|
|
{
|
|
return new pass_return_slot (ctxt);
|
|
}
|