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|
/* Functions to analyze and validate GIMPLE trees.
Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>
Rewritten by Jason Merrill <jason@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 2, 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 COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "ggc.h"
#include "tm.h"
#include "tree.h"
#include "tree-gimple.h"
#include "tree-flow.h"
#include "output.h"
#include "rtl.h"
#include "expr.h"
#include "bitmap.h"
/* GCC GIMPLE structure
Inspired by the SIMPLE C grammar at
http://www-acaps.cs.mcgill.ca/info/McCAT/McCAT.html
function : FUNCTION_DECL
DECL_SAVED_TREE -> compound-stmt
compound-stmt: STATEMENT_LIST
members -> stmt
stmt : block
| if-stmt
| switch-stmt
| goto-stmt
| return-stmt
| resx-stmt
| label-stmt
| try-stmt
| modify-stmt
| call-stmt
block : BIND_EXPR
BIND_EXPR_VARS -> chain of DECLs
BIND_EXPR_BLOCK -> BLOCK
BIND_EXPR_BODY -> compound-stmt
if-stmt : COND_EXPR
op0 -> condition
op1 -> compound-stmt
op2 -> compound-stmt
switch-stmt : SWITCH_EXPR
op0 -> val
op1 -> NULL
op2 -> TREE_VEC of CASE_LABEL_EXPRs
The CASE_LABEL_EXPRs are sorted by CASE_LOW,
and default is last.
goto-stmt : GOTO_EXPR
op0 -> LABEL_DECL | val
return-stmt : RETURN_EXPR
op0 -> return-value
return-value : NULL
| RESULT_DECL
| MODIFY_EXPR
op0 -> RESULT_DECL
op1 -> lhs
resx-stmt : RESX_EXPR
label-stmt : LABEL_EXPR
op0 -> LABEL_DECL
try-stmt : TRY_CATCH_EXPR
op0 -> compound-stmt
op1 -> handler
| TRY_FINALLY_EXPR
op0 -> compound-stmt
op1 -> compound-stmt
handler : catch-seq
| EH_FILTER_EXPR
| compound-stmt
catch-seq : STATEMENT_LIST
members -> CATCH_EXPR
modify-stmt : MODIFY_EXPR
op0 -> lhs
op1 -> rhs
call-stmt : CALL_EXPR
op0 -> val | OBJ_TYPE_REF
op1 -> call-arg-list
call-arg-list: TREE_LIST
members -> lhs
addr-expr-arg: ID
| compref
addressable : addr-expr-arg
| indirectref
with-size-arg: addressable
| call-stmt
indirectref : INDIRECT_REF
op0 -> val
lhs : addressable
| bitfieldref
| WITH_SIZE_EXPR
op0 -> with-size-arg
op1 -> val
min-lval : ID
| indirectref
bitfieldref : BIT_FIELD_REF
op0 -> inner-compref
op1 -> CONST
op2 -> var
compref : inner-compref
| REALPART_EXPR
op0 -> inner-compref
| IMAGPART_EXPR
op0 -> inner-compref
inner-compref: min-lval
| COMPONENT_REF
op0 -> inner-compref
op1 -> FIELD_DECL
op2 -> val
| ARRAY_REF
op0 -> inner-compref
op1 -> val
op2 -> val
op3 -> val
| ARRAY_RANGE_REF
op0 -> inner-compref
op1 -> val
op2 -> val
op3 -> val
| VIEW_CONVERT_EXPR
op0 -> inner-compref
condition : val
| RELOP
op0 -> val
op1 -> val
val : ID
| CONST
rhs : lhs
| CONST
| call-stmt
| ADDR_EXPR
op0 -> addr-expr-arg
| UNOP
op0 -> val
| BINOP
op0 -> val
op1 -> val
| RELOP
op0 -> val
op1 -> val
*/
static inline bool is_gimple_id (tree);
/* Validation of GIMPLE expressions. */
/* Return true if T is a GIMPLE RHS for an assignment to a temporary. */
bool
is_gimple_tmp_rhs (tree t)
{
enum tree_code code = TREE_CODE (t);
switch (TREE_CODE_CLASS (code))
{
case '1':
case '2':
case '<':
return true;
default:
break;
}
switch (code)
{
case TRUTH_NOT_EXPR:
case TRUTH_AND_EXPR:
case TRUTH_OR_EXPR:
case TRUTH_XOR_EXPR:
case ADDR_EXPR:
case CALL_EXPR:
case CONSTRUCTOR:
case COMPLEX_EXPR:
case INTEGER_CST:
case REAL_CST:
case STRING_CST:
case COMPLEX_CST:
case VECTOR_CST:
case OBJ_TYPE_REF:
return true;
default:
break;
}
return is_gimple_lvalue (t) || is_gimple_val (t);
}
/* Returns true iff T is a valid RHS for an assignment to a renamed user
variable. */
bool
is_gimple_reg_rhs (tree t)
{
/* If the RHS of the MODIFY_EXPR may throw or make a nonlocal goto and
the LHS is a user variable, then we need to introduce a temporary.
ie temp = RHS; LHS = temp.
This way the optimizers can determine that the user variable is
only modified if evaluation of the RHS does not throw. */
if (is_gimple_reg_type (TREE_TYPE (t))
&& TREE_SIDE_EFFECTS (t)
&& (TREE_CODE (t) == CALL_EXPR
|| (flag_non_call_exceptions && tree_could_trap_p (t))))
return is_gimple_val (t);
else
/* Don't force a temp of a non-renamable type; the copy could be
arbitrarily expensive. Instead we will generate a V_MAY_DEF for
the assignment. */
return is_gimple_tmp_rhs (t);
}
/* Returns true iff T is a valid RHS for an assignment to an un-renamed
LHS, or for a call argument. */
bool
is_gimple_mem_rhs (tree t)
{
/* If we're dealing with a renamable type, either source or dest
must be a renamed variable. */
if (is_gimple_reg_type (TREE_TYPE (t)))
return is_gimple_val (t);
else
return is_gimple_tmp_rhs (t);
}
/* Returns the appropriate RHS predicate for this LHS. */
gimple_predicate
rhs_predicate_for (tree lhs)
{
if (is_gimple_tmp_var (lhs))
return is_gimple_tmp_rhs;
else if (is_gimple_reg (lhs))
return is_gimple_reg_rhs;
else
return is_gimple_mem_rhs;
}
/* Returns true if T is a valid CONSTRUCTOR component in GIMPLE, either
a val or another CONSTRUCTOR. */
bool
is_gimple_constructor_elt (tree t)
{
return (is_gimple_val (t)
|| TREE_CODE (t) == CONSTRUCTOR);
}
/* Return true if T is a valid LHS for a GIMPLE assignment expression. */
bool
is_gimple_lvalue (tree t)
{
return (is_gimple_addressable (t)
|| TREE_CODE (t) == WITH_SIZE_EXPR
/* These are complex lvalues, but don't have addresses, so they
go here. */
|| TREE_CODE (t) == BIT_FIELD_REF);
}
/* Return true if T is a GIMPLE condition. */
bool
is_gimple_condexpr (tree t)
{
return (is_gimple_val (t)
|| TREE_CODE_CLASS (TREE_CODE (t)) == '<');
}
/* Return true if T is something whose address can be taken. */
bool
is_gimple_addressable (tree t)
{
return (is_gimple_id (t) || handled_component_p (t)
|| TREE_CODE (t) == REALPART_EXPR
|| TREE_CODE (t) == IMAGPART_EXPR
|| TREE_CODE (t) == INDIRECT_REF);
}
/* Return true if T is function invariant. Or rather a restricted
form of function invariant. */
bool
is_gimple_min_invariant (tree t)
{
switch (TREE_CODE (t))
{
case ADDR_EXPR:
return TREE_INVARIANT (t);
case INTEGER_CST:
case REAL_CST:
case STRING_CST:
case COMPLEX_CST:
case VECTOR_CST:
return !TREE_OVERFLOW (t);
default:
return false;
}
}
/* Return true if T looks like a valid GIMPLE statement. */
bool
is_gimple_stmt (tree t)
{
enum tree_code code = TREE_CODE (t);
if (IS_EMPTY_STMT (t))
return 1;
switch (code)
{
case BIND_EXPR:
case COND_EXPR:
/* These are only valid if they're void. */
return TREE_TYPE (t) == NULL || VOID_TYPE_P (TREE_TYPE (t));
case SWITCH_EXPR:
case GOTO_EXPR:
case RETURN_EXPR:
case LABEL_EXPR:
case CASE_LABEL_EXPR:
case TRY_CATCH_EXPR:
case TRY_FINALLY_EXPR:
case EH_FILTER_EXPR:
case CATCH_EXPR:
case ASM_EXPR:
case RESX_EXPR:
case PHI_NODE:
case STATEMENT_LIST:
/* These are always void. */
return true;
case CALL_EXPR:
case MODIFY_EXPR:
/* These are valid regardless of their type. */
return true;
default:
return false;
}
}
/* Return true if T is a variable. */
bool
is_gimple_variable (tree t)
{
return (TREE_CODE (t) == VAR_DECL
|| TREE_CODE (t) == PARM_DECL
|| TREE_CODE (t) == RESULT_DECL
|| TREE_CODE (t) == SSA_NAME);
}
/* Return true if T is a GIMPLE identifier (something with an address). */
static inline bool
is_gimple_id (tree t)
{
return (is_gimple_variable (t)
|| TREE_CODE (t) == FUNCTION_DECL
|| TREE_CODE (t) == LABEL_DECL
|| TREE_CODE (t) == CONST_DECL
/* Allow string constants, since they are addressable. */
|| TREE_CODE (t) == STRING_CST);
}
/* Return true if TYPE is a suitable type for a scalar register variable. */
bool
is_gimple_reg_type (tree type)
{
return (!AGGREGATE_TYPE_P (type)
&& TREE_CODE (type) != COMPLEX_TYPE);
}
/* Return true if T is a scalar register variable. */
bool
is_gimple_reg (tree t)
{
if (TREE_CODE (t) == SSA_NAME)
t = SSA_NAME_VAR (t);
return (is_gimple_variable (t)
&& is_gimple_reg_type (TREE_TYPE (t))
/* A volatile decl is not acceptable because we can't reuse it as
needed. We need to copy it into a temp first. */
&& ! TREE_THIS_VOLATILE (t)
&& ! needs_to_live_in_memory (t));
}
/* Returns true if T is a GIMPLE temporary variable, false otherwise. */
bool
is_gimple_tmp_var (tree t)
{
/* FIXME this could trigger for other local artificials, too. */
return (TREE_CODE (t) == VAR_DECL && DECL_ARTIFICIAL (t)
&& !TREE_STATIC (t) && !DECL_EXTERNAL (t));
}
/* Returns true if T is a GIMPLE temporary register variable. */
bool
is_gimple_tmp_reg (tree t)
{
/* The intent of this is to get hold of a value that won't change.
An SSA_NAME qualifies no matter if its of a user variable or not. */
if (TREE_CODE (t) == SSA_NAME)
return true;
/* We don't know the lifetime characteristics of user variables. */
if (TREE_CODE (t) != VAR_DECL || !DECL_ARTIFICIAL (t))
return false;
/* Finally, it must be capable of being placed in a register. */
return is_gimple_reg (t);
}
/* Return true if T is a GIMPLE variable whose address is not needed. */
bool
is_gimple_non_addressable (tree t)
{
if (TREE_CODE (t) == SSA_NAME)
t = SSA_NAME_VAR (t);
return (is_gimple_variable (t) && ! needs_to_live_in_memory (t));
}
/* Return true if T is a GIMPLE rvalue, i.e. an identifier or a constant. */
bool
is_gimple_val (tree t)
{
/* Make loads from volatiles and memory vars explicit. */
if (is_gimple_variable (t)
&& is_gimple_reg_type (TREE_TYPE (t))
&& !is_gimple_reg (t))
return false;
/* FIXME make these decls. That can happen only when we expose the
entire landing-pad construct at the tree level. */
if (TREE_CODE (t) == EXC_PTR_EXPR || TREE_CODE (t) == FILTER_EXPR)
return 1;
return (is_gimple_variable (t) || is_gimple_min_invariant (t));
}
/* Return true if T is a GIMPLE minimal lvalue. */
bool
is_gimple_min_lval (tree t)
{
return (is_gimple_id (t)
|| TREE_CODE (t) == INDIRECT_REF);
}
/* Return true if T is a typecast operation. */
bool
is_gimple_cast (tree t)
{
return (TREE_CODE (t) == NOP_EXPR
|| TREE_CODE (t) == CONVERT_EXPR
|| TREE_CODE (t) == FIX_TRUNC_EXPR
|| TREE_CODE (t) == FIX_CEIL_EXPR
|| TREE_CODE (t) == FIX_FLOOR_EXPR
|| TREE_CODE (t) == FIX_ROUND_EXPR);
}
/* Return true if T is a valid op0 of a CALL_EXPR. */
bool
is_gimple_call_addr (tree t)
{
return (TREE_CODE (t) == OBJ_TYPE_REF
|| is_gimple_val (t));
}
/* If T makes a function call, return the corresponding CALL_EXPR operand.
Otherwise, return NULL_TREE. */
tree
get_call_expr_in (tree t)
{
if (TREE_CODE (t) == MODIFY_EXPR)
t = TREE_OPERAND (t, 1);
if (TREE_CODE (t) == WITH_SIZE_EXPR)
t = TREE_OPERAND (t, 0);
if (TREE_CODE (t) == CALL_EXPR)
return t;
return NULL_TREE;
}
/* Given a memory reference expression, return the base address. Note that,
in contrast with get_base_var, this will not recurse inside INDIRECT_REF
expressions. Therefore, given the reference PTR->FIELD, this function
will return *PTR. Whereas get_base_var would've returned PTR. */
tree
get_base_address (tree t)
{
while (TREE_CODE (t) == REALPART_EXPR || TREE_CODE (t) == IMAGPART_EXPR
|| handled_component_p (t))
t = TREE_OPERAND (t, 0);
if (SSA_VAR_P (t)
|| TREE_CODE (t) == STRING_CST
|| TREE_CODE (t) == CONSTRUCTOR
|| TREE_CODE (t) == INDIRECT_REF)
return t;
else
return NULL_TREE;
}
void
recalculate_side_effects (tree t)
{
enum tree_code code = TREE_CODE (t);
int fro = first_rtl_op (code);
int i;
switch (TREE_CODE_CLASS (code))
{
case 'e':
switch (code)
{
case INIT_EXPR:
case MODIFY_EXPR:
case VA_ARG_EXPR:
case PREDECREMENT_EXPR:
case PREINCREMENT_EXPR:
case POSTDECREMENT_EXPR:
case POSTINCREMENT_EXPR:
/* All of these have side-effects, no matter what their
operands are. */
return;
default:
break;
}
/* Fall through. */
case '<': /* a comparison expression */
case '1': /* a unary arithmetic expression */
case '2': /* a binary arithmetic expression */
case 'r': /* a reference */
TREE_SIDE_EFFECTS (t) = TREE_THIS_VOLATILE (t);
for (i = 0; i < fro; ++i)
{
tree op = TREE_OPERAND (t, i);
if (op && TREE_SIDE_EFFECTS (op))
TREE_SIDE_EFFECTS (t) = 1;
}
break;
}
}
|