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/* Code for range operators.
Copyright (C) 2017-2024 Free Software Foundation, Inc.
Contributed by Andrew MacLeod <amacleod@redhat.com>
and Aldy Hernandez <aldyh@redhat.com>.
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 "insn-codes.h"
#include "rtl.h"
#include "tree.h"
#include "gimple.h"
#include "cfghooks.h"
#include "tree-pass.h"
#include "ssa.h"
#include "optabs-tree.h"
#include "gimple-pretty-print.h"
#include "diagnostic-core.h"
#include "flags.h"
#include "fold-const.h"
#include "stor-layout.h"
#include "calls.h"
#include "cfganal.h"
#include "gimple-iterator.h"
#include "gimple-fold.h"
#include "tree-eh.h"
#include "gimple-walk.h"
#include "tree-cfg.h"
#include "wide-int.h"
#include "value-relation.h"
#include "range-op.h"
#include "tree-ssa-ccp.h"
#include "range-op-mixed.h"
class pointer_plus_operator : public range_operator
{
using range_operator::op2_range;
public:
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio = TRIO_VARYING) const;
void update_bitmask (irange &r, const irange &lh, const irange &rh) const
{ update_known_bitmask (r, POINTER_PLUS_EXPR, lh, rh); }
} op_pointer_plus;
void
pointer_plus_operator::wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const
{
// Check for [0,0] + const, and simply return the const.
if (lh_lb == 0 && lh_ub == 0 && rh_lb == rh_ub)
{
r.set (type, rh_lb, rh_lb);
return;
}
// For pointer types, we are really only interested in asserting
// whether the expression evaluates to non-NULL.
//
// With -fno-delete-null-pointer-checks we need to be more
// conservative. As some object might reside at address 0,
// then some offset could be added to it and the same offset
// subtracted again and the result would be NULL.
// E.g.
// static int a[12]; where &a[0] is NULL and
// ptr = &a[6];
// ptr -= 6;
// ptr will be NULL here, even when there is POINTER_PLUS_EXPR
// where the first range doesn't include zero and the second one
// doesn't either. As the second operand is sizetype (unsigned),
// consider all ranges where the MSB could be set as possible
// subtractions where the result might be NULL.
if ((!wi_includes_zero_p (type, lh_lb, lh_ub)
|| !wi_includes_zero_p (type, rh_lb, rh_ub))
&& !TYPE_OVERFLOW_WRAPS (type)
&& (flag_delete_null_pointer_checks
|| !wi::sign_mask (rh_ub)))
r = range_nonzero (type);
else if (lh_lb == lh_ub && lh_lb == 0
&& rh_lb == rh_ub && rh_lb == 0)
r = range_zero (type);
else
r.set_varying (type);
}
bool
pointer_plus_operator::op2_range (irange &r, tree type,
const irange &lhs ATTRIBUTE_UNUSED,
const irange &op1 ATTRIBUTE_UNUSED,
relation_trio trio) const
{
relation_kind rel = trio.lhs_op1 ();
r.set_varying (type);
// If the LHS and OP1 are equal, the op2 must be zero.
if (rel == VREL_EQ)
r.set_zero (type);
// If the LHS and OP1 are not equal, the offset must be non-zero.
else if (rel == VREL_NE)
r.set_nonzero (type);
else
return false;
return true;
}
class pointer_min_max_operator : public range_operator
{
public:
virtual void wi_fold (irange & r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const;
} op_ptr_min_max;
void
pointer_min_max_operator::wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const
{
// For MIN/MAX expressions with pointers, we only care about
// nullness. If both are non null, then the result is nonnull.
// If both are null, then the result is null. Otherwise they
// are varying.
if (!wi_includes_zero_p (type, lh_lb, lh_ub)
&& !wi_includes_zero_p (type, rh_lb, rh_ub))
r = range_nonzero (type);
else if (wi_zero_p (type, lh_lb, lh_ub) && wi_zero_p (type, rh_lb, rh_ub))
r = range_zero (type);
else
r.set_varying (type);
}
class pointer_and_operator : public range_operator
{
public:
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const;
} op_pointer_and;
void
pointer_and_operator::wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb ATTRIBUTE_UNUSED,
const wide_int &rh_ub ATTRIBUTE_UNUSED) const
{
// For pointer types, we are really only interested in asserting
// whether the expression evaluates to non-NULL.
if (wi_zero_p (type, lh_lb, lh_ub) || wi_zero_p (type, lh_lb, lh_ub))
r = range_zero (type);
else
r.set_varying (type);
}
class pointer_or_operator : public range_operator
{
public:
using range_operator::op1_range;
using range_operator::op2_range;
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio rel = TRIO_VARYING) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio rel = TRIO_VARYING) const;
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const;
} op_pointer_or;
bool
pointer_or_operator::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2 ATTRIBUTE_UNUSED,
relation_trio) const
{
if (lhs.undefined_p ())
return false;
if (lhs.zero_p ())
{
r.set_zero (type);
return true;
}
r.set_varying (type);
return true;
}
bool
pointer_or_operator::op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio) const
{
return pointer_or_operator::op1_range (r, type, lhs, op1);
}
void
pointer_or_operator::wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const
{
// For pointer types, we are really only interested in asserting
// whether the expression evaluates to non-NULL.
if (!wi_includes_zero_p (type, lh_lb, lh_ub)
&& !wi_includes_zero_p (type, rh_lb, rh_ub))
r = range_nonzero (type);
else if (wi_zero_p (type, lh_lb, lh_ub) && wi_zero_p (type, rh_lb, rh_ub))
r = range_zero (type);
else
r.set_varying (type);
}
class operator_pointer_diff : public range_operator
{
virtual bool op1_op2_relation_effect (irange &lhs_range,
tree type,
const irange &op1_range,
const irange &op2_range,
relation_kind rel) const;
void update_bitmask (irange &r, const irange &lh, const irange &rh) const
{ update_known_bitmask (r, POINTER_DIFF_EXPR, lh, rh); }
} op_pointer_diff;
bool
operator_pointer_diff::op1_op2_relation_effect (irange &lhs_range, tree type,
const irange &op1_range,
const irange &op2_range,
relation_kind rel) const
{
return minus_op1_op2_relation_effect (lhs_range, type, op1_range, op2_range,
rel);
}
// ----------------------------------------------------------------------
// Hybrid operators for the 4 operations which integer and pointers share,
// but which have different implementations. Simply check the type in
// the call and choose the appropriate method.
// Once there is a PRANGE signature, simply add the appropriate
// prototypes in the rmixed range class, and remove these hybrid classes.
class hybrid_and_operator : public operator_bitwise_and
{
public:
using range_operator::op1_range;
using range_operator::op2_range;
using range_operator::lhs_op1_relation;
bool op1_range (irange &r, tree type,
const irange &lhs, const irange &op2,
relation_trio rel = TRIO_VARYING) const final override
{
if (INTEGRAL_TYPE_P (type))
return operator_bitwise_and::op1_range (r, type, lhs, op2, rel);
else
return false;
}
bool op2_range (irange &r, tree type,
const irange &lhs, const irange &op1,
relation_trio rel = TRIO_VARYING) const final override
{
if (INTEGRAL_TYPE_P (type))
return operator_bitwise_and::op2_range (r, type, lhs, op1, rel);
else
return false;
}
relation_kind lhs_op1_relation (const irange &lhs,
const irange &op1, const irange &op2,
relation_kind rel) const final override
{
if (!lhs.undefined_p () && INTEGRAL_TYPE_P (lhs.type ()))
return operator_bitwise_and::lhs_op1_relation (lhs, op1, op2, rel);
else
return VREL_VARYING;
}
void update_bitmask (irange &r, const irange &lh,
const irange &rh) const final override
{
if (!r.undefined_p () && INTEGRAL_TYPE_P (r.type ()))
operator_bitwise_and::update_bitmask (r, lh, rh);
}
void wi_fold (irange &r, tree type, const wide_int &lh_lb,
const wide_int &lh_ub, const wide_int &rh_lb,
const wide_int &rh_ub) const final override
{
if (INTEGRAL_TYPE_P (type))
return operator_bitwise_and::wi_fold (r, type, lh_lb, lh_ub,
rh_lb, rh_ub);
else
return op_pointer_and.wi_fold (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
}
} op_hybrid_and;
// Temporary class which dispatches routines to either the INT version or
// the pointer version depending on the type. Once PRANGE is a range
// class, we can remove the hybrid.
class hybrid_or_operator : public operator_bitwise_or
{
public:
using range_operator::op1_range;
using range_operator::op2_range;
using range_operator::lhs_op1_relation;
bool op1_range (irange &r, tree type,
const irange &lhs, const irange &op2,
relation_trio rel = TRIO_VARYING) const final override
{
if (INTEGRAL_TYPE_P (type))
return operator_bitwise_or::op1_range (r, type, lhs, op2, rel);
else
return op_pointer_or.op1_range (r, type, lhs, op2, rel);
}
bool op2_range (irange &r, tree type,
const irange &lhs, const irange &op1,
relation_trio rel = TRIO_VARYING) const final override
{
if (INTEGRAL_TYPE_P (type))
return operator_bitwise_or::op2_range (r, type, lhs, op1, rel);
else
return op_pointer_or.op2_range (r, type, lhs, op1, rel);
}
void update_bitmask (irange &r, const irange &lh,
const irange &rh) const final override
{
if (!r.undefined_p () && INTEGRAL_TYPE_P (r.type ()))
operator_bitwise_or::update_bitmask (r, lh, rh);
}
void wi_fold (irange &r, tree type, const wide_int &lh_lb,
const wide_int &lh_ub, const wide_int &rh_lb,
const wide_int &rh_ub) const final override
{
if (INTEGRAL_TYPE_P (type))
return operator_bitwise_or::wi_fold (r, type, lh_lb, lh_ub,
rh_lb, rh_ub);
else
return op_pointer_or.wi_fold (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
}
} op_hybrid_or;
// Temporary class which dispatches routines to either the INT version or
// the pointer version depending on the type. Once PRANGE is a range
// class, we can remove the hybrid.
class hybrid_min_operator : public operator_min
{
public:
void update_bitmask (irange &r, const irange &lh,
const irange &rh) const final override
{
if (!r.undefined_p () && INTEGRAL_TYPE_P (r.type ()))
operator_min::update_bitmask (r, lh, rh);
}
void wi_fold (irange &r, tree type, const wide_int &lh_lb,
const wide_int &lh_ub, const wide_int &rh_lb,
const wide_int &rh_ub) const final override
{
if (INTEGRAL_TYPE_P (type))
return operator_min::wi_fold (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
else
return op_ptr_min_max.wi_fold (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
}
} op_hybrid_min;
class hybrid_max_operator : public operator_max
{
public:
void update_bitmask (irange &r, const irange &lh,
const irange &rh) const final override
{
if (!r.undefined_p () && INTEGRAL_TYPE_P (r.type ()))
operator_max::update_bitmask (r, lh, rh);
}
void wi_fold (irange &r, tree type, const wide_int &lh_lb,
const wide_int &lh_ub, const wide_int &rh_lb,
const wide_int &rh_ub) const final override
{
if (INTEGRAL_TYPE_P (type))
return operator_max::wi_fold (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
else
return op_ptr_min_max.wi_fold (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
}
} op_hybrid_max;
// Initialize any pointer operators to the primary table
void
range_op_table::initialize_pointer_ops ()
{
set (POINTER_PLUS_EXPR, op_pointer_plus);
set (POINTER_DIFF_EXPR, op_pointer_diff);
set (BIT_AND_EXPR, op_hybrid_and);
set (BIT_IOR_EXPR, op_hybrid_or);
set (MIN_EXPR, op_hybrid_min);
set (MAX_EXPR, op_hybrid_max);
}
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