/* Alias analysis for GNU C
- Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
+ Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
Free Software Foundation, Inc.
Contributed by John Carr (jfc@mit.edu).
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. */
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "target.h"
#include "cgraph.h"
#include "varray.h"
+#include "tree-pass.h"
+#include "ipa-type-escape.h"
+
+/* The aliasing API provided here solves related but different problems:
+
+ Say there exists (in c)
+
+ struct X {
+ struct Y y1;
+ struct Z z2;
+ } x1, *px1, *px2;
+
+ struct Y y2, *py;
+ struct Z z2, *pz;
+
+
+ py = &px1.y1;
+ px2 = &x1;
+
+ Consider the four questions:
+
+ Can a store to x1 interfere with px2->y1?
+ Can a store to x1 interfere with px2->z2?
+ (*px2).z2
+ Can a store to x1 change the value pointed to by with py?
+ Can a store to x1 change the value pointed to by with pz?
+
+ The answer to these questions can be yes, yes, yes, and maybe.
+
+ The first two questions can be answered with a simple examination
+ of the type system. If structure X contains a field of type Y then
+ a store thru a pointer to an X can overwrite any field that is
+ contained (recursively) in an X (unless we know that px1 != px2).
+
+ The last two of the questions can be solved in the same way as the
+ first two questions but this is too conservative. The observation
+ is that in some cases analysis we can know if which (if any) fields
+ are addressed and if those addresses are used in bad ways. This
+ analysis may be language specific. In C, arbitrary operations may
+ be applied to pointers. However, there is some indication that
+ this may be too conservative for some C++ types.
+
+ The pass ipa-type-escape does this analysis for the types whose
+ instances do not escape across the compilation boundary.
+
+ Historically in GCC, these two problems were combined and a single
+ data structure was used to represent the solution to these
+ problems. We now have two similar but different data structures,
+ The data structure to solve the last two question is similar to the
+ first, but does not contain have the fields in it whose address are
+ never taken. For types that do escape the compilation unit, the
+ data structures will have identical information.
+*/
/* The alias sets assigned to MEMs assist the back-end in determining
which MEMs can alias which other MEMs. In general, two MEMs in
static tree decl_for_component_ref (tree);
static rtx adjust_offset_for_component_ref (tree, rtx);
static int nonoverlapping_memrefs_p (rtx, rtx);
-static int write_dependence_p (rtx, rtx, int, int);
-
-static int nonlocal_mentioned_p_1 (rtx *, void *);
-static int nonlocal_mentioned_p (rtx);
-static int nonlocal_referenced_p_1 (rtx *, void *);
-static int nonlocal_referenced_p (rtx);
-static int nonlocal_set_p_1 (rtx *, void *);
-static int nonlocal_set_p (rtx);
+static int write_dependence_p (rtx, rtx, int);
+
static void memory_modified_1 (rtx, rtx, void *);
+static void record_alias_subset (HOST_WIDE_INT, HOST_WIDE_INT);
/* Set up all info needed to perform alias analysis on memory references. */
static inline int
mems_in_disjoint_alias_sets_p (rtx mem1, rtx mem2)
{
-#ifdef ENABLE_CHECKING
/* Perform a basic sanity check. Namely, that there are no alias sets
if we're not using strict aliasing. This helps to catch bugs
whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or
gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to
use alias sets to indicate that spilled registers cannot alias each
other, we might need to remove this check. */
- if (! flag_strict_aliasing
- && (MEM_ALIAS_SET (mem1) != 0 || MEM_ALIAS_SET (mem2) != 0))
- abort ();
-#endif
+ gcc_assert (flag_strict_aliasing
+ || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2)));
return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2));
}
}
\f
-/* Return 1 if TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE and has
- has any readonly fields. If any of the fields have types that
- contain readonly fields, return true as well. */
-
-int
-readonly_fields_p (tree type)
-{
- tree field;
-
- if (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
- && TREE_CODE (type) != QUAL_UNION_TYPE)
- return 0;
-
- for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field))
- if (TREE_CODE (field) == FIELD_DECL
- && (TREE_READONLY (field)
- || readonly_fields_p (TREE_TYPE (field))))
- return 1;
-
- return 0;
-}
-\f
/* Return 1 if any MEM object of type T1 will always conflict (using the
dependency routines in this file) with any MEM object of type T2.
This is used when allocating temporary storage. If T1 and/or T2 are
if (t1 == 0 && t2 == 0)
return 0;
- /* If one or the other has readonly fields or is readonly,
- then they may not conflict. */
- if ((t1 != 0 && readonly_fields_p (t1))
- || (t2 != 0 && readonly_fields_p (t2))
- || (t1 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t1))
- || (t2 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t2)))
- return 0;
-
/* If they are the same type, they must conflict. */
if (t1 == t2
/* Likewise if both are volatile. */
static tree
find_base_decl (tree t)
{
- tree d0, d1, d2;
+ tree d0, d1;
if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t)))
return 0;
- /* If this is a declaration, return it. */
- if (TREE_CODE_CLASS (TREE_CODE (t)) == 'd')
- return t;
+ /* If this is a declaration, return it. If T is based on a restrict
+ qualified decl, return that decl. */
+ if (DECL_P (t))
+ {
+ if (TREE_CODE (t) == VAR_DECL && DECL_BASED_ON_RESTRICT_P (t))
+ t = DECL_GET_RESTRICT_BASE (t);
+ return t;
+ }
/* Handle general expressions. It would be nice to deal with
COMPONENT_REFs here. If we could tell that `a' and `b' were the
same, then `a->f' and `b->f' are also the same. */
switch (TREE_CODE_CLASS (TREE_CODE (t)))
{
- case '1':
+ case tcc_unary:
return find_base_decl (TREE_OPERAND (t, 0));
- case '2':
+ case tcc_binary:
/* Return 0 if found in neither or both are the same. */
d0 = find_base_decl (TREE_OPERAND (t, 0));
d1 = find_base_decl (TREE_OPERAND (t, 1));
else
return 0;
- case '3':
- d0 = find_base_decl (TREE_OPERAND (t, 0));
- d1 = find_base_decl (TREE_OPERAND (t, 1));
- d2 = find_base_decl (TREE_OPERAND (t, 2));
-
- /* Set any nonzero values from the last, then from the first. */
- if (d1 == 0) d1 = d2;
- if (d0 == 0) d0 = d1;
- if (d1 == 0) d1 = d0;
- if (d2 == 0) d2 = d1;
-
- /* At this point all are nonzero or all are zero. If all three are the
- same, return it. Otherwise, return zero. */
- return (d0 == d1 && d1 == d2) ? d0 : 0;
-
default:
return 0;
}
}
-/* Return 1 if all the nested component references handled by
- get_inner_reference in T are such that we can address the object in T. */
+/* Return true if all nested component references handled by
+ get_inner_reference in T are such that we should use the alias set
+ provided by the object at the heart of T.
-int
-can_address_p (tree t)
+ This is true for non-addressable components (which don't have their
+ own alias set), as well as components of objects in alias set zero.
+ This later point is a special case wherein we wish to override the
+ alias set used by the component, but we don't have per-FIELD_DECL
+ assignable alias sets. */
+
+bool
+component_uses_parent_alias_set (tree t)
{
- /* If we're at the end, it is vacuously addressable. */
- if (! handled_component_p (t))
- return 1;
+ while (1)
+ {
+ /* If we're at the end, it vacuously uses its own alias set. */
+ if (!handled_component_p (t))
+ return false;
- /* Bitfields are never addressable. */
- else if (TREE_CODE (t) == BIT_FIELD_REF)
- return 0;
+ switch (TREE_CODE (t))
+ {
+ case COMPONENT_REF:
+ if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)))
+ return true;
+ break;
- /* Fields are addressable unless they are marked as nonaddressable or
- the containing type has alias set 0. */
- else if (TREE_CODE (t) == COMPONENT_REF
- && ! DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))
- && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0
- && can_address_p (TREE_OPERAND (t, 0)))
- return 1;
+ case ARRAY_REF:
+ case ARRAY_RANGE_REF:
+ if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))))
+ return true;
+ break;
- /* Likewise for arrays. */
- else if ((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
- && ! TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))
- && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0
- && can_address_p (TREE_OPERAND (t, 0)))
- return 1;
+ case REALPART_EXPR:
+ case IMAGPART_EXPR:
+ break;
- return 0;
+ default:
+ /* Bitfields and casts are never addressable. */
+ return true;
+ }
+
+ t = TREE_OPERAND (t, 0);
+ if (get_alias_set (TREE_TYPE (t)) == 0)
+ return true;
+ }
}
/* Return the alias set for T, which may be either a type or an
}
/* Check for accesses through restrict-qualified pointers. */
- if (TREE_CODE (inner) == INDIRECT_REF)
+ if (INDIRECT_REF_P (inner))
{
tree decl = find_base_decl (TREE_OPERAND (inner, 0));
type, then we would believe that other subsets
of the pointed-to type (such as fields of that
type) do not conflict with the type pointed to
- by the restricted pointer. */
+ by the restricted pointer. */
DECL_POINTER_ALIAS_SET (decl)
= pointed_to_alias_set;
else
/* Otherwise, pick up the outermost object that we could have a pointer
to, processing conversions as above. */
- while (handled_component_p (t) && ! can_address_p (t))
+ while (component_uses_parent_alias_set (t))
{
t = TREE_OPERAND (t, 0);
STRIP_NOPS (t);
It is illegal for SUPERSET to be zero; everything is implicitly a
subset of alias set zero. */
-void
+static void
record_alias_subset (HOST_WIDE_INT superset, HOST_WIDE_INT subset)
{
alias_set_entry superset_entry;
if (superset == subset)
return;
- if (superset == 0)
- abort ();
+ gcc_assert (superset);
superset_entry = get_alias_set_entry (superset);
if (superset_entry == 0)
case UNION_TYPE:
case QUAL_UNION_TYPE:
/* Recursively record aliases for the base classes, if there are any. */
- if (TYPE_BINFO (type) != NULL && TYPE_BINFO_BASETYPES (type) != NULL)
+ if (TYPE_BINFO (type))
{
int i;
- for (i = 0; i < TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (type)); i++)
- {
- tree binfo = TREE_VEC_ELT (TYPE_BINFO_BASETYPES (type), i);
- record_alias_subset (superset,
- get_alias_set (BINFO_TYPE (binfo)));
- }
+ tree binfo, base_binfo;
+
+ for (binfo = TYPE_BINFO (type), i = 0;
+ BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
+ record_alias_subset (superset,
+ get_alias_set (BINFO_TYPE (base_binfo)));
}
for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field))
if (TREE_CODE (field) == FIELD_DECL && ! DECL_NONADDRESSABLE_P (field))
regno = REGNO (dest);
- if (regno >= VARRAY_SIZE (reg_base_value))
- abort ();
+ gcc_assert (regno < VARRAY_SIZE (reg_base_value));
/* If this spans multiple hard registers, then we must indicate that every
register has an unusable value. */
contain anything but integers and other rtx's,
except for within LABEL_REFs and SYMBOL_REFs. */
default:
- abort ();
+ gcc_unreachable ();
}
}
return 1;
where SIZE is the size in bytes of the memory reference. If ADDR
is not modified by the memory reference then ADDR is returned. */
-rtx
+static rtx
addr_side_effect_eval (rtx addr, int size, int n_refs)
{
int offset = 0;
aliases_everything_p (rtx mem)
{
if (GET_CODE (XEXP (mem, 0)) == AND)
- /* If the address is an AND, its very hard to know at what it is
+ /* If the address is an AND, it's very hard to know at what it is
actually pointing. */
return 1;
do
{
fieldx = TREE_OPERAND (x, 1);
- typex = DECL_FIELD_CONTEXT (fieldx);
+ typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx));
y = orig_y;
do
{
fieldy = TREE_OPERAND (y, 1);
- typey = DECL_FIELD_CONTEXT (fieldy);
+ typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy));
if (typex == typey)
goto found;
x = TREE_OPERAND (x, 0);
}
while (x && TREE_CODE (x) == COMPONENT_REF);
-
/* Never found a common type. */
return false;
/* Unless both have exprs, we can't tell anything. */
if (exprx == 0 || expry == 0)
return 0;
-
+
/* If both are field references, we may be able to determine something. */
if (TREE_CODE (exprx) == COMPONENT_REF
&& TREE_CODE (expry) == COMPONENT_REF
&& nonoverlapping_component_refs_p (exprx, expry))
return 1;
+
/* If the field reference test failed, look at the DECLs involved. */
moffsetx = MEM_OFFSET (x);
if (TREE_CODE (exprx) == COMPONENT_REF)
{
- tree t = decl_for_component_ref (exprx);
- if (! t)
- return 0;
- moffsetx = adjust_offset_for_component_ref (exprx, moffsetx);
- exprx = t;
+ if (TREE_CODE (expry) == VAR_DECL
+ && POINTER_TYPE_P (TREE_TYPE (expry)))
+ {
+ tree field = TREE_OPERAND (exprx, 1);
+ tree fieldcontext = DECL_FIELD_CONTEXT (field);
+ if (ipa_type_escape_field_does_not_clobber_p (fieldcontext,
+ TREE_TYPE (field)))
+ return 1;
+ }
+ {
+ tree t = decl_for_component_ref (exprx);
+ if (! t)
+ return 0;
+ moffsetx = adjust_offset_for_component_ref (exprx, moffsetx);
+ exprx = t;
+ }
}
- else if (TREE_CODE (exprx) == INDIRECT_REF)
+ else if (INDIRECT_REF_P (exprx))
{
exprx = TREE_OPERAND (exprx, 0);
if (flag_argument_noalias < 2
moffsety = MEM_OFFSET (y);
if (TREE_CODE (expry) == COMPONENT_REF)
{
- tree t = decl_for_component_ref (expry);
- if (! t)
- return 0;
- moffsety = adjust_offset_for_component_ref (expry, moffsety);
- expry = t;
+ if (TREE_CODE (exprx) == VAR_DECL
+ && POINTER_TYPE_P (TREE_TYPE (exprx)))
+ {
+ tree field = TREE_OPERAND (expry, 1);
+ tree fieldcontext = DECL_FIELD_CONTEXT (field);
+ if (ipa_type_escape_field_does_not_clobber_p (fieldcontext,
+ TREE_TYPE (field)))
+ return 1;
+ }
+ {
+ tree t = decl_for_component_ref (expry);
+ if (! t)
+ return 0;
+ moffsety = adjust_offset_for_component_ref (expry, moffsety);
+ expry = t;
+ }
}
- else if (TREE_CODE (expry) == INDIRECT_REF)
+ else if (INDIRECT_REF_P (expry))
{
expry = TREE_OPERAND (expry, 0);
if (flag_argument_noalias < 2
return 1;
if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
return 1;
+ if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
+ || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
+ return 1;
if (DIFFERENT_ALIAS_SETS_P (x, mem))
return 0;
- /* Unchanging memory can't conflict with non-unchanging memory.
- A non-unchanging read can conflict with a non-unchanging write.
- An unchanging read can conflict with an unchanging write since
- there may be a single store to this address to initialize it.
- Note that an unchanging store can conflict with a non-unchanging read
- since we have to make conservative assumptions when we have a
- record with readonly fields and we are copying the whole thing.
- Just fall through to the code below to resolve potential conflicts.
- This won't handle all cases optimally, but the possible performance
- loss should be negligible. */
- if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem))
+ /* Read-only memory is by definition never modified, and therefore can't
+ conflict with anything. We don't expect to find read-only set on MEM,
+ but stupid user tricks can produce them, so don't die. */
+ if (MEM_READONLY_P (x))
return 0;
if (nonoverlapping_memrefs_p (mem, x))
return 1;
if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
return 1;
+ if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
+ || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
+ return 1;
if (DIFFERENT_ALIAS_SETS_P (x, mem))
return 0;
- /* If X is an unchanging read, then it can't possibly conflict with any
- non-unchanging store. It may conflict with an unchanging write though,
- because there may be a single store to this address to initialize it.
- Just fall through to the code below to resolve the case where we have
- both an unchanging read and an unchanging write. This won't handle all
- cases optimally, but the possible performance loss should be
- negligible. */
- if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem))
+ /* Read-only memory is by definition never modified, and therefore can't
+ conflict with anything. We don't expect to find read-only set on MEM,
+ but stupid user tricks can produce them, so don't die. */
+ if (MEM_READONLY_P (x))
return 0;
if (nonoverlapping_memrefs_p (x, mem))
}
/* Returns nonzero if a write to X might alias a previous read from
- (or, if WRITEP is nonzero, a write to) MEM. If CONSTP is nonzero,
- honor the RTX_UNCHANGING_P flags on X and MEM. */
+ (or, if WRITEP is nonzero, a write to) MEM. */
static int
-write_dependence_p (rtx mem, rtx x, int writep, int constp)
+write_dependence_p (rtx mem, rtx x, int writep)
{
rtx x_addr, mem_addr;
rtx fixed_scalar;
return 1;
if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
return 1;
+ if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
+ || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
+ return 1;
if (DIFFERENT_ALIAS_SETS_P (x, mem))
return 0;
- if (constp)
- {
- /* Unchanging memory can't conflict with non-unchanging memory. */
- if (RTX_UNCHANGING_P (x) != RTX_UNCHANGING_P (mem))
- return 0;
-
- /* If MEM is an unchanging read, then it can't possibly conflict with
- the store to X, because there is at most one store to MEM, and it
- must have occurred somewhere before MEM. */
- if (! writep && RTX_UNCHANGING_P (mem))
- return 0;
- }
+ /* A read from read-only memory can't conflict with read-write memory. */
+ if (!writep && MEM_READONLY_P (mem))
+ return 0;
if (nonoverlapping_memrefs_p (x, mem))
return 0;
int
anti_dependence (rtx mem, rtx x)
{
- return write_dependence_p (mem, x, /*writep=*/0, /*constp*/1);
+ return write_dependence_p (mem, x, /*writep=*/0);
}
/* Output dependence: X is written after store in MEM takes place. */
int
output_dependence (rtx mem, rtx x)
{
- return write_dependence_p (mem, x, /*writep=*/1, /*constp*/1);
-}
-
-/* Unchanging anti dependence: Like anti_dependence but ignores
- the UNCHANGING_RTX_P property on const variable references. */
-
-int
-unchanging_anti_dependence (rtx mem, rtx x)
-{
- return write_dependence_p (mem, x, /*writep=*/0, /*constp*/0);
-}
-\f
-/* A subroutine of nonlocal_mentioned_p, returns 1 if *LOC mentions
- something which is not local to the function and is not constant. */
-
-static int
-nonlocal_mentioned_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED)
-{
- rtx x = *loc;
- rtx base;
- int regno;
-
- if (! x)
- return 0;
-
- switch (GET_CODE (x))
- {
- case SUBREG:
- if (REG_P (SUBREG_REG (x)))
- {
- /* Global registers are not local. */
- if (REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER
- && global_regs[subreg_regno (x)])
- return 1;
- return 0;
- }
- break;
-
- case REG:
- regno = REGNO (x);
- /* Global registers are not local. */
- if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
- return 1;
- return 0;
-
- case SCRATCH:
- case PC:
- case CC0:
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_VECTOR:
- case CONST:
- case LABEL_REF:
- return 0;
-
- case SYMBOL_REF:
- /* Constants in the function's constants pool are constant. */
- if (CONSTANT_POOL_ADDRESS_P (x))
- return 0;
- return 1;
-
- case CALL:
- /* Non-constant calls and recursion are not local. */
- return 1;
-
- case MEM:
- /* Be overly conservative and consider any volatile memory
- reference as not local. */
- if (MEM_VOLATILE_P (x))
- return 1;
- base = find_base_term (XEXP (x, 0));
- if (base)
- {
- /* A Pmode ADDRESS could be a reference via the structure value
- address or static chain. Such memory references are nonlocal.
-
- Thus, we have to examine the contents of the ADDRESS to find
- out if this is a local reference or not. */
- if (GET_CODE (base) == ADDRESS
- && GET_MODE (base) == Pmode
- && (XEXP (base, 0) == stack_pointer_rtx
- || XEXP (base, 0) == arg_pointer_rtx
-#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
- || XEXP (base, 0) == hard_frame_pointer_rtx
-#endif
- || XEXP (base, 0) == frame_pointer_rtx))
- return 0;
- /* Constants in the function's constant pool are constant. */
- if (GET_CODE (base) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (base))
- return 0;
- }
- return 1;
-
- case UNSPEC_VOLATILE:
- case ASM_INPUT:
- return 1;
-
- case ASM_OPERANDS:
- if (MEM_VOLATILE_P (x))
- return 1;
-
- /* Fall through. */
-
- default:
- break;
- }
-
- return 0;
-}
-
-/* Returns nonzero if X might mention something which is not
- local to the function and is not constant. */
-
-static int
-nonlocal_mentioned_p (rtx x)
-{
- if (INSN_P (x))
- {
- if (GET_CODE (x) == CALL_INSN)
- {
- if (! CONST_OR_PURE_CALL_P (x))
- return 1;
- x = CALL_INSN_FUNCTION_USAGE (x);
- if (x == 0)
- return 0;
- }
- else
- x = PATTERN (x);
- }
-
- return for_each_rtx (&x, nonlocal_mentioned_p_1, NULL);
-}
-
-/* A subroutine of nonlocal_referenced_p, returns 1 if *LOC references
- something which is not local to the function and is not constant. */
-
-static int
-nonlocal_referenced_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED)
-{
- rtx x = *loc;
-
- if (! x)
- return 0;
-
- switch (GET_CODE (x))
- {
- case MEM:
- case REG:
- case SYMBOL_REF:
- case SUBREG:
- return nonlocal_mentioned_p (x);
-
- case CALL:
- /* Non-constant calls and recursion are not local. */
- return 1;
-
- case SET:
- if (nonlocal_mentioned_p (SET_SRC (x)))
- return 1;
-
- if (MEM_P (SET_DEST (x)))
- return nonlocal_mentioned_p (XEXP (SET_DEST (x), 0));
-
- /* If the destination is anything other than a CC0, PC,
- MEM, REG, or a SUBREG of a REG that occupies all of
- the REG, then X references nonlocal memory if it is
- mentioned in the destination. */
- if (GET_CODE (SET_DEST (x)) != CC0
- && GET_CODE (SET_DEST (x)) != PC
- && !REG_P (SET_DEST (x))
- && ! (GET_CODE (SET_DEST (x)) == SUBREG
- && REG_P (SUBREG_REG (SET_DEST (x)))
- && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x))))
- + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)
- == ((GET_MODE_SIZE (GET_MODE (SET_DEST (x)))
- + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD))))
- return nonlocal_mentioned_p (SET_DEST (x));
- return 0;
-
- case CLOBBER:
- if (MEM_P (XEXP (x, 0)))
- return nonlocal_mentioned_p (XEXP (XEXP (x, 0), 0));
- return 0;
-
- case USE:
- return nonlocal_mentioned_p (XEXP (x, 0));
-
- case ASM_INPUT:
- case UNSPEC_VOLATILE:
- return 1;
-
- case ASM_OPERANDS:
- if (MEM_VOLATILE_P (x))
- return 1;
-
- /* Fall through. */
-
- default:
- break;
- }
-
- return 0;
-}
-
-/* Returns nonzero if X might reference something which is not
- local to the function and is not constant. */
-
-static int
-nonlocal_referenced_p (rtx x)
-{
- if (INSN_P (x))
- {
- if (GET_CODE (x) == CALL_INSN)
- {
- if (! CONST_OR_PURE_CALL_P (x))
- return 1;
- x = CALL_INSN_FUNCTION_USAGE (x);
- if (x == 0)
- return 0;
- }
- else
- x = PATTERN (x);
- }
-
- return for_each_rtx (&x, nonlocal_referenced_p_1, NULL);
-}
-
-/* A subroutine of nonlocal_set_p, returns 1 if *LOC sets
- something which is not local to the function and is not constant. */
-
-static int
-nonlocal_set_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED)
-{
- rtx x = *loc;
-
- if (! x)
- return 0;
-
- switch (GET_CODE (x))
- {
- case CALL:
- /* Non-constant calls and recursion are not local. */
- return 1;
-
- case PRE_INC:
- case PRE_DEC:
- case POST_INC:
- case POST_DEC:
- case PRE_MODIFY:
- case POST_MODIFY:
- return nonlocal_mentioned_p (XEXP (x, 0));
-
- case SET:
- if (nonlocal_mentioned_p (SET_DEST (x)))
- return 1;
- return nonlocal_set_p (SET_SRC (x));
-
- case CLOBBER:
- return nonlocal_mentioned_p (XEXP (x, 0));
-
- case USE:
- return 0;
-
- case ASM_INPUT:
- case UNSPEC_VOLATILE:
- return 1;
-
- case ASM_OPERANDS:
- if (MEM_VOLATILE_P (x))
- return 1;
-
- /* Fall through. */
-
- default:
- break;
- }
-
- return 0;
-}
-
-/* Returns nonzero if X might set something which is not
- local to the function and is not constant. */
-
-static int
-nonlocal_set_p (rtx x)
-{
- if (INSN_P (x))
- {
- if (GET_CODE (x) == CALL_INSN)
- {
- if (! CONST_OR_PURE_CALL_P (x))
- return 1;
- x = CALL_INSN_FUNCTION_USAGE (x);
- if (x == 0)
- return 0;
- }
- else
- x = PATTERN (x);
- }
-
- return for_each_rtx (&x, nonlocal_set_p_1, NULL);
-}
-
-/* Mark the function if it is pure or constant. */
-
-void
-mark_constant_function (void)
-{
- rtx insn;
- int nonlocal_memory_referenced;
-
- if (TREE_READONLY (current_function_decl)
- || DECL_IS_PURE (current_function_decl)
- || TREE_THIS_VOLATILE (current_function_decl)
- || current_function_has_nonlocal_goto
- || !targetm.binds_local_p (current_function_decl))
- return;
-
- /* A loop might not return which counts as a side effect. */
- if (mark_dfs_back_edges ())
- return;
-
- nonlocal_memory_referenced = 0;
-
- init_alias_analysis ();
-
- /* Determine if this is a constant or pure function. */
-
- for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
- {
- if (! INSN_P (insn))
- continue;
-
- if (nonlocal_set_p (insn) || global_reg_mentioned_p (insn)
- || volatile_refs_p (PATTERN (insn)))
- break;
-
- if (! nonlocal_memory_referenced)
- nonlocal_memory_referenced = nonlocal_referenced_p (insn);
- }
-
- end_alias_analysis ();
-
- /* Mark the function. */
-
- if (insn)
- ;
- else if (nonlocal_memory_referenced)
- {
- cgraph_rtl_info (current_function_decl)->pure_function = 1;
- DECL_IS_PURE (current_function_decl) = 1;
- }
- else
- {
- cgraph_rtl_info (current_function_decl)->const_function = 1;
- TREE_READONLY (current_function_decl) = 1;
- }
+ return write_dependence_p (mem, x, /*writep=*/1);
}
\f
/* Return true when INSN possibly modify memory contents of MEM
- (ie address can be modified). */
+ (i.e. address can be modified). */
bool
memory_modified_in_insn_p (rtx mem, rtx insn)
{
VARRAY_RTX_INIT (reg_base_value, maxreg, "reg_base_value");
}
- new_reg_base_value = xmalloc (maxreg * sizeof (rtx));
- reg_seen = xmalloc (maxreg);
- if (! reload_completed && flag_old_unroll_loops)
- {
- alias_invariant = ggc_calloc (maxreg, sizeof (rtx));
- alias_invariant_size = maxreg;
- }
+ new_reg_base_value = XNEWVEC (rtx, maxreg);
+ reg_seen = XNEWVEC (char, maxreg);
/* The basic idea is that each pass through this loop will use the
"constant" information from the previous pass to propagate alias
}
}
}
- else if (GET_CODE (insn) == NOTE
+ else if (NOTE_P (insn)
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
copying_arguments = false;
}
/* Now propagate values from new_reg_base_value to reg_base_value. */
- if (maxreg != (unsigned int) max_reg_num())
- abort ();
+ gcc_assert (maxreg == (unsigned int) max_reg_num());
+
for (ui = 0; ui < maxreg; ui++)
{
if (new_reg_base_value[ui]
alias_invariant_size = 0;
}
}
+\f
+/* Do control and data flow analysis; write some of the results to the
+ dump file. */
+static void
+rest_of_handle_cfg (void)
+{
+ if (dump_file)
+ dump_flow_info (dump_file, dump_flags);
+ if (optimize)
+ cleanup_cfg (CLEANUP_EXPENSIVE
+ | (flag_thread_jumps ? CLEANUP_THREADING : 0));
+}
+
+struct tree_opt_pass pass_cfg =
+{
+ "cfg", /* name */
+ NULL, /* gate */
+ rest_of_handle_cfg, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_FLOW, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func, /* todo_flags_finish */
+ 'f' /* letter */
+};
+
#include "gt-alias.h"
OSDN Git Service
