+2006-01-16 Daniel Berlin <dberlin@dberlin.org>
+
+ * tree-ssa-operands.h (ssa_call_clobbered_cache_valid): Remove.
+ (ssa_ro_call_cache_valid): Ditto.
+ * tree-ssa-alias.c (sort_tags_by_id): New function.
+ (init_transitive_clobber_worklist): Ditto.
+ (add_to_worklist): Ditto.
+ (mark_aliases_call_clobbered): Ditto.
+ (compute_tag_properties): Ditto.
+ (set_initial_properties): Ditto.
+ (compute_call_clobbered): Ditto.
+ (compute_may_aliases): Call compute_call_clobbered and grouping.
+ (compute_flow_sensitive_aliasing): Remove clobbering related code.
+ (compute_flow_insensitive_aliasing): Grouping now happens in our
+ caller.
+ (setup_pointers_and_addressables): Remove clobbering related code.
+ (add_may_alias): Ditto.
+ (replace_may_alias): Ditto.
+ (get_nmt_for): Ditto.
+ (create_global_var):
+ (is_escape_site): Return an escape_type enumeration.
+ * tree-flow-inline.h (is_call_clobbered): Global var does not
+ imply call clobbered.
+ (mark_call_clobbered): Take a reason for marking this. Remove
+ marking of globalness, and cache invalidation.
+ (clear_call_clobbered): Remove cache invalidation code.
+ * tree-dfa.c (dump_variable): If details is on, dump the reason
+ for escaping.
+ * tree-outof-ssa.c (create_temp): Copy escape mask from original
+ variable.
+ * tree-flow.h (struct ptr_info_def): Add escape mask member.
+ (struct var_ann_d): Ditto.
+ (enum escape_type): New.
+ (mark_call_clobbered): Adjust prototype.
+ * tree-ssa-structalias.c (update_alias_info): Unmodifiable vars
+ are never call clobbered.
+ Record reasons for escaping.
+ * tree-ssa-structalias.h (is_escape_site): Update prototype.
+ * tree-ssa-operands.c (ssa_call_clobbered_cache_valid): Remove.
+ (ssa_ro_call_cache_valid): Ditto.
+ (clobbered_v_may_defs): Ditto.
+ (clobbered_vuses): Ditto.
+ (ro_call_vuses): Ditto.
+ (clobber_stats): New.
+ (init_ssa_operands): Zero out clobber stats.
+ (fini_ssa_operands): Print out clobber stats.
+ (get_call_expr_operands): Pass callee fndecl to
+ add_call_read_ops).
+ (add_call_clobber_ops): Remove use of cache.
+ Add use of PURE_CONST information.
+ (add_call_read_ops): Remove use of cache.
+ Add use of static not_read information.
+
2006-01-18 Alexandre Oliva <aoliva@redhat.com>
Introduce TLS descriptors for i386 and x86_64.
+2006-01-18 Daniel Berlin <dberlin@dberlin.org>
+
+ * gcc.dg/tree-ssa/pr24287.c: New test
+
2006-01-18 Eric Christopher <echristo@apple.com>
* g++.dg/eh/table.C: New.
--- /dev/null
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+int g1(int);
+int h(int *a, int *b)__attribute__((pure));
+void link_error();
+
+/* The calls to link_error should be eliminated, since nothing escapes to
+ non-pure functions. */
+int g(void)
+{
+ int t = 0, t1 = 2;
+ int t2 = h(&t, &t1);
+ if (t != 0)
+ link_error ();
+ if (t1 != 2)
+ link_error ();
+ g1(t2);
+ if (t != 0)
+ link_error ();
+ if (t1 != 2)
+ link_error ();
+ return t2 == 2;
+}
+/* { dg-final { scan-tree-dump-times "link_error" 0 "optimized"} } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
fprintf (file, ", is volatile");
if (is_call_clobbered (var))
- fprintf (file, ", call clobbered");
+ {
+ fprintf (file, ", call clobbered");
+ if (dump_flags & TDF_DETAILS)
+ {
+ var_ann_t va = var_ann (var);
+ unsigned int escape_mask = va->escape_mask;
+
+ fprintf (file, " (");
+ if (escape_mask & ESCAPE_STORED_IN_GLOBAL)
+ fprintf (file, ", stored in global");
+ if (escape_mask & ESCAPE_TO_ASM)
+ fprintf (file, ", goes through ASM");
+ if (escape_mask & ESCAPE_TO_CALL)
+ fprintf (file, ", passed to call");
+ if (escape_mask & ESCAPE_BAD_CAST)
+ fprintf (file, ", bad cast");
+ if (escape_mask & ESCAPE_TO_RETURN)
+ fprintf (file, ", returned from func");
+ if (escape_mask & ESCAPE_TO_PURE_CONST)
+ fprintf (file, ", passed to pure/const");
+ if (escape_mask & ESCAPE_IS_GLOBAL)
+ fprintf (file, ", is global var");
+ if (escape_mask & ESCAPE_IS_PARM)
+ fprintf (file, ", is incoming pointer");
+ if (escape_mask & ESCAPE_UNKNOWN)
+ fprintf (file, ", unknown escape");
+ fprintf (file, " )");
+ }
+ }
if (default_def (var))
{
*slot = (void *) var;
referenced_var_insert (DECL_UID (var), var);
-
- /* Global variables are always call-clobbered. */
- if (is_global_var (var))
- mark_call_clobbered (var);
-
+
/* Tag's don't have DECL_INITIAL. */
if (MTAG_P (var))
return;
-
+
/* Scan DECL_INITIAL for pointer variables as they may contain
address arithmetic referencing the address of other
variables. */
static inline bool
is_call_clobbered (tree var)
{
- return is_global_var (var)
- || bitmap_bit_p (call_clobbered_vars, DECL_UID (var));
+ return bitmap_bit_p (call_clobbered_vars, DECL_UID (var));
}
/* Mark variable VAR as being clobbered by function calls. */
static inline void
-mark_call_clobbered (tree var)
+mark_call_clobbered (tree var, unsigned int escape_type)
{
- /* If VAR is a memory tag, then we need to consider it a global
- variable. This is because the pointer that VAR represents has
- been found to point to either an arbitrary location or to a known
- location in global memory. */
- if (MTAG_P (var) && TREE_CODE (var) != STRUCT_FIELD_TAG)
- MTAG_GLOBAL (var) = 1;
+ var_ann (var)->escape_mask |= escape_type;
bitmap_set_bit (call_clobbered_vars, DECL_UID (var));
- ssa_call_clobbered_cache_valid = false;
- ssa_ro_call_cache_valid = false;
}
/* Clear the call-clobbered attribute from variable VAR. */
static inline void
clear_call_clobbered (tree var)
{
+ var_ann_t ann = var_ann (var);
+ ann->escape_mask = 0;
if (MTAG_P (var) && TREE_CODE (var) != STRUCT_FIELD_TAG)
MTAG_GLOBAL (var) = 0;
bitmap_clear_bit (call_clobbered_vars, DECL_UID (var));
- ssa_call_clobbered_cache_valid = false;
- ssa_ro_call_cache_valid = false;
}
/* Mark variable VAR as being non-addressable. */
{
bitmap_clear_bit (call_clobbered_vars, DECL_UID (var));
TREE_ADDRESSABLE (var) = 0;
- ssa_call_clobbered_cache_valid = false;
- ssa_ro_call_cache_valid = false;
}
/* Return the common annotation for T. Return NULL if the annotation
pointer will be represented by this memory tag, instead of the type
tag computed by TBAA. */
tree name_mem_tag;
+
+ /* Mask of reasons this pointer's value escapes the function */
+ unsigned int escape_mask;
};
/* If this variable is a structure, this fields holds a list of
symbols representing each of the fields of the structure. */
subvar_t subvars;
+
+ /* Mask of values saying the reasons why this variable has escaped
+ the function. */
+ unsigned int escape_mask;
};
struct function_ann_d GTY(())
};
extern enum move_pos movement_possibility (tree);
+/* The reasons a variable may escape a function. */
+enum escape_type
+ {
+ NO_ESCAPE = 0, /* Doesn't escape. */
+ ESCAPE_STORED_IN_GLOBAL = 1 << 1,
+ ESCAPE_TO_ASM = 1 << 2, /* Passed by address to an assembly
+ statement. */
+ ESCAPE_TO_CALL = 1 << 3, /* Escapes to a function call. */
+ ESCAPE_BAD_CAST = 1 << 4, /* Cast from pointer to integer */
+ ESCAPE_TO_RETURN = 1 << 5, /* Returned from function. */
+ ESCAPE_TO_PURE_CONST = 1 << 6, /* Escapes to a pure or constant
+ function call. */
+ ESCAPE_IS_GLOBAL = 1 << 7, /* Is a global variable. */
+ ESCAPE_IS_PARM = 1 << 8, /* Is an incoming function parameter. */
+ ESCAPE_UNKNOWN = 1 << 9 /* We believe it escapes for some reason
+ not enumerated above. */
+ };
+
/* In tree-flow-inline.h */
static inline bool is_call_clobbered (tree);
-static inline void mark_call_clobbered (tree);
+static inline void mark_call_clobbered (tree, unsigned int);
static inline void set_is_used (tree);
static inline bool unmodifiable_var_p (tree);
inherit from our original variable. */
var_ann (tmp)->type_mem_tag = var_ann (t)->type_mem_tag;
if (is_call_clobbered (t))
- mark_call_clobbered (tmp);
+ mark_call_clobbered (tmp, var_ann (t)->escape_mask);
return tmp;
}
having to keep track of too many V_MAY_DEF expressions at call sites. */
tree global_var;
+DEF_VEC_I(int);
+DEF_VEC_ALLOC_I(int,heap);
+
+/* qsort comparison function to sort type/name tags by DECL_UID. */
+
+static int
+sort_tags_by_id (const void *pa, const void *pb)
+{
+ tree a = *(tree *)pa;
+ tree b = *(tree *)pb;
+
+ return DECL_UID (a) - DECL_UID (b);
+}
+
+/* Initialize WORKLIST to contain those memory tags that are marked call
+ clobbered. Initialized WORKLIST2 to contain the reasons these
+ memory tags escaped. */
+
+static void
+init_transitive_clobber_worklist (VEC (tree, heap) **worklist,
+ VEC (int, heap) **worklist2)
+{
+ referenced_var_iterator rvi;
+ tree curr;
+
+ FOR_EACH_REFERENCED_VAR (curr, rvi)
+ {
+ if (MTAG_P (curr) && is_call_clobbered (curr))
+ {
+ VEC_safe_push (tree, heap, *worklist, curr);
+ VEC_safe_push (int, heap, *worklist2, var_ann (curr)->escape_mask);
+ }
+ }
+}
+
+/* Add ALIAS to WORKLIST (and the reason for escaping REASON to WORKLIST2) if
+ ALIAS is not already marked call clobbered, and is a memory
+ tag. */
+
+static void
+add_to_worklist (tree alias, VEC (tree, heap) **worklist,
+ VEC (int, heap) **worklist2,
+ int reason)
+{
+ if (MTAG_P (alias) && !is_call_clobbered (alias))
+ {
+ VEC_safe_push (tree, heap, *worklist, alias);
+ VEC_safe_push (int, heap, *worklist2, reason);
+ }
+}
+
+/* Mark aliases of TAG as call clobbered, and place any tags on the
+ alias list that were not already call clobbered on WORKLIST. */
+
+static void
+mark_aliases_call_clobbered (tree tag, VEC (tree, heap) **worklist,
+ VEC (int, heap) **worklist2)
+{
+ unsigned int i;
+ VEC (tree, gc) *ma;
+ tree entry;
+ var_ann_t ta = var_ann (tag);
+
+ if (!MTAG_P (tag))
+ return;
+ ma = may_aliases (tag);
+ if (!ma)
+ return;
+
+ for (i = 0; VEC_iterate (tree, ma, i, entry); i++)
+ {
+ if (!unmodifiable_var_p (entry))
+ {
+ add_to_worklist (entry, worklist, worklist2, ta->escape_mask);
+ mark_call_clobbered (entry, ta->escape_mask);
+ }
+ }
+}
+
+/* Tags containing global vars need to be marked as global.
+ Tags containing call clobbered vars need to be marked as call
+ clobbered. */
+
+static void
+compute_tag_properties (void)
+{
+ referenced_var_iterator rvi;
+ tree tag;
+ bool changed = true;
+ VEC (tree, heap) *taglist = NULL;
+
+ FOR_EACH_REFERENCED_VAR (tag, rvi)
+ {
+ if (!MTAG_P (tag) || TREE_CODE (tag) == STRUCT_FIELD_TAG)
+ continue;
+ VEC_safe_push (tree, heap, taglist, tag);
+ }
+
+ /* We sort the taglist by DECL_UID, for two reasons.
+ 1. To get a sequential ordering to make the bitmap accesses
+ faster.
+ 2. Because of the way we compute aliases, it's more likely that
+ an earlier tag is included in a later tag, and this will reduce
+ the number of iterations.
+
+ If we had a real tag graph, we would just topo-order it and be
+ done with it. */
+ qsort (VEC_address (tree, taglist),
+ VEC_length (tree, taglist),
+ sizeof (tree),
+ sort_tags_by_id);
+
+ /* Go through each tag not marked as global, and if it aliases
+ global vars, mark it global.
+
+ If the tag contains call clobbered vars, mark it call
+ clobbered.
+
+ This loop iterates because tags may appear in the may-aliases
+ list of other tags when we group. */
+
+ while (changed)
+ {
+ unsigned int k;
+
+ changed = false;
+ for (k = 0; VEC_iterate (tree, taglist, k, tag); k++)
+ {
+ VEC (tree, gc) *ma;
+ unsigned int i;
+ tree entry;
+ bool tagcc = is_call_clobbered (tag);
+ bool tagglobal = MTAG_GLOBAL (tag);
+
+ if (tagcc && tagglobal)
+ continue;
+
+ ma = may_aliases (tag);
+ if (!ma)
+ continue;
+
+ for (i = 0; VEC_iterate (tree, ma, i, entry); i++)
+ {
+ /* Call clobbered entries cause the tag to be marked
+ call clobbered. */
+ if (!tagcc && is_call_clobbered (entry))
+ {
+ mark_call_clobbered (tag, var_ann (entry)->escape_mask);
+ tagcc = true;
+ changed = true;
+ }
+
+ /* Global vars cause the tag to be marked global. */
+ if (!tagglobal && is_global_var (entry))
+ {
+ MTAG_GLOBAL (tag) = true;
+ changed = true;
+ tagglobal = true;
+ }
+
+ /* Early exit once both global and cc are set, since the
+ loop can't do any more than that. */
+ if (tagcc && tagglobal)
+ break;
+ }
+ }
+ }
+ VEC_free (tree, heap, taglist);
+}
+
+/* Set up the initial variable clobbers and globalness.
+ When this function completes, only tags whose aliases need to be
+ clobbered will be set clobbered. Tags clobbered because they
+ contain call clobbered vars are handled in compute_tag_properties. */
+
+static void
+set_initial_properties (struct alias_info *ai)
+{
+ unsigned int i;
+ referenced_var_iterator rvi;
+ tree var;
+
+ FOR_EACH_REFERENCED_VAR (var, rvi)
+ {
+ if (is_global_var (var)
+ && (!var_can_have_subvars (var)
+ || get_subvars_for_var (var) == NULL))
+ {
+ if (!unmodifiable_var_p (var))
+ mark_call_clobbered (var, ESCAPE_IS_GLOBAL);
+ }
+ else if (TREE_CODE (var) == PARM_DECL
+ && default_def (var)
+ && POINTER_TYPE_P (TREE_TYPE (var)))
+ {
+ tree def = default_def (var);
+ get_ptr_info (def)->value_escapes_p = 1;
+ get_ptr_info (def)->escape_mask |= ESCAPE_IS_PARM;
+ }
+ }
+
+ for (i = 0; i < VARRAY_ACTIVE_SIZE (ai->processed_ptrs); i++)
+ {
+ tree ptr = VARRAY_TREE (ai->processed_ptrs, i);
+ struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
+ var_ann_t v_ann = var_ann (SSA_NAME_VAR (ptr));
+
+ if (pi->value_escapes_p)
+ {
+ /* If PTR escapes then its associated memory tags and
+ pointed-to variables are call-clobbered. */
+ if (pi->name_mem_tag)
+ mark_call_clobbered (pi->name_mem_tag, pi->escape_mask);
+
+ if (v_ann->type_mem_tag)
+ mark_call_clobbered (v_ann->type_mem_tag, pi->escape_mask);
+
+ if (pi->pt_vars)
+ {
+ bitmap_iterator bi;
+ unsigned int j;
+ EXECUTE_IF_SET_IN_BITMAP (pi->pt_vars, 0, j, bi)
+ if (!unmodifiable_var_p (referenced_var (j)))
+ mark_call_clobbered (referenced_var (j), pi->escape_mask);
+ }
+ }
+ /* If the name tag is call clobbered, so is the type tag
+ associated with the base VAR_DECL. */
+ if (pi->name_mem_tag
+ && v_ann->type_mem_tag
+ && is_call_clobbered (pi->name_mem_tag))
+ mark_call_clobbered (v_ann->type_mem_tag, pi->escape_mask);
+
+ /* Name tags and type tags that we don't know where they point
+ to, might point to global memory, and thus, are clobbered.
+
+ FIXME: This is not quite right. They should only be
+ clobbered if value_escapes_p is true, regardless of whether
+ they point to global memory or not.
+ So removing this code and fixing all the bugs would be nice.
+ It is the cause of a bunch of clobbering. */
+ if ((pi->pt_global_mem || pi->pt_anything)
+ && pi->is_dereferenced && pi->name_mem_tag)
+ {
+ mark_call_clobbered (pi->name_mem_tag, ESCAPE_IS_GLOBAL);
+ MTAG_GLOBAL (pi->name_mem_tag) = true;
+ }
+
+ if ((pi->pt_global_mem || pi->pt_anything)
+ && pi->is_dereferenced && v_ann->type_mem_tag)
+ {
+ mark_call_clobbered (v_ann->type_mem_tag, ESCAPE_IS_GLOBAL);
+ MTAG_GLOBAL (v_ann->type_mem_tag) = true;
+ }
+ }
+}
+
+/* Compute which variables need to be marked call clobbered because
+ their tag is call clobbered, and which tags need to be marked
+ global because they contain global variables. */
+
+static void
+compute_call_clobbered (struct alias_info *ai)
+{
+ VEC (tree, heap) *worklist = NULL;
+ VEC(int,heap) *worklist2 = NULL;
+
+ set_initial_properties (ai);
+ init_transitive_clobber_worklist (&worklist, &worklist2);
+ while (VEC_length (tree, worklist) != 0)
+ {
+ tree curr = VEC_pop (tree, worklist);
+ int reason = VEC_pop (int, worklist2);
+
+ mark_call_clobbered (curr, reason);
+ mark_aliases_call_clobbered (curr, &worklist, &worklist2);
+ }
+ VEC_free (tree, heap, worklist);
+ VEC_free (int, heap, worklist2);
+ compute_tag_properties ();
+}
/* Compute may-alias information for every variable referenced in function
FNDECL.
memory tags. */
compute_flow_insensitive_aliasing (ai);
+ /* Determine if we need to enable alias grouping. */
+ if (ai->total_alias_vops >= MAX_ALIASED_VOPS)
+ group_aliases (ai);
+
+ /* Compute call clobbering information. */
+ compute_call_clobbered (ai);
+
/* If the program has too many call-clobbered variables and/or function
calls, create .GLOBAL_VAR and use it to model call-clobbering
semantics at call sites. This reduces the number of virtual operands
var_ann_t v_ann = var_ann (SSA_NAME_VAR (ptr));
bitmap_iterator bi;
- if (pi->value_escapes_p || pi->pt_anything)
- {
- /* If PTR escapes or may point to anything, then its associated
- memory tags and pointed-to variables are call-clobbered. */
- if (pi->name_mem_tag)
- mark_call_clobbered (pi->name_mem_tag);
-
- if (v_ann->type_mem_tag)
- mark_call_clobbered (v_ann->type_mem_tag);
-
- if (pi->pt_vars)
- EXECUTE_IF_SET_IN_BITMAP (pi->pt_vars, 0, j, bi)
- mark_call_clobbered (referenced_var (j));
- }
/* Set up aliasing information for PTR's name memory tag (if it has
one). Note that only pointers that have been dereferenced will
add_may_alias (pi->name_mem_tag, referenced_var (j));
add_may_alias (v_ann->type_mem_tag, referenced_var (j));
}
-
- /* If the name tag is call clobbered, so is the type tag
- associated with the base VAR_DECL. */
- if (pi->name_mem_tag
- && v_ann->type_mem_tag
- && is_call_clobbered (pi->name_mem_tag))
- mark_call_clobbered (v_ann->type_mem_tag);
}
}
fprintf (dump_file, "\n%s: Total number of aliased vops: %ld\n",
get_name (current_function_decl),
ai->total_alias_vops);
-
- /* Determine if we need to enable alias grouping. */
- if (ai->total_alias_vops >= MAX_ALIASED_VOPS)
- group_aliases (ai);
}
if (bitmap_bit_p (ai->dereferenced_ptrs_store, DECL_UID (var)))
bitmap_set_bit (ai->written_vars, DECL_UID (tag));
- /* If pointer VAR is a global variable or a PARM_DECL,
- then its memory tag should be considered a global
- variable. */
- if (TREE_CODE (var) == PARM_DECL || is_global_var (var))
- mark_call_clobbered (tag);
-
/* All the dereferences of pointer VAR count as
references of TAG. Since TAG can be associated with
several pointers, add the dereferences of VAR to the
if (alias == al)
return;
- /* If VAR is a call-clobbered variable, so is its new ALIAS.
- FIXME, call-clobbering should only depend on whether an address
- escapes. It should be independent of aliasing. */
- if (is_call_clobbered (var))
- mark_call_clobbered (alias);
-
- /* Likewise. If ALIAS is call-clobbered, so is VAR. */
- else if (is_call_clobbered (alias))
- mark_call_clobbered (var);
-
VEC_safe_push (tree, gc, v_ann->may_aliases, alias);
a_ann->is_alias_tag = 1;
}
{
var_ann_t v_ann = var_ann (var);
VEC_replace (tree, v_ann->may_aliases, i, new_alias);
-
- /* If VAR is a call-clobbered variable, so is NEW_ALIAS.
- FIXME, call-clobbering should only depend on whether an address
- escapes. It should be independent of aliasing. */
- if (is_call_clobbered (var))
- mark_call_clobbered (new_alias);
-
- /* Likewise. If NEW_ALIAS is call-clobbered, so is VAR. */
- else if (is_call_clobbered (new_alias))
- mark_call_clobbered (var);
}
3- STMT is an assignment to a non-local variable, or
4- STMT is a return statement.
- AI points to the alias information collected so far. */
+ AI points to the alias information collected so far.
-bool
+ Return the type of escape site found, if we found one, or NO_ESCAPE
+ if none. */
+
+enum escape_type
is_escape_site (tree stmt, struct alias_info *ai)
{
tree call = get_call_expr_in (stmt);
ai->num_calls_found++;
if (!TREE_SIDE_EFFECTS (call))
- ai->num_pure_const_calls_found++;
+ {
+ ai->num_pure_const_calls_found++;
+ return ESCAPE_TO_PURE_CONST;
+ }
- return true;
+ return ESCAPE_TO_CALL;
}
else if (TREE_CODE (stmt) == ASM_EXPR)
- return true;
+ return ESCAPE_TO_ASM;
else if (TREE_CODE (stmt) == MODIFY_EXPR)
{
tree lhs = TREE_OPERAND (stmt, 0);
/* If we couldn't recognize the LHS of the assignment, assume that it
is a non-local store. */
if (lhs == NULL_TREE)
- return true;
+ return ESCAPE_UNKNOWN;
/* If the RHS is a conversion between a pointer and an integer, the
pointer escapes since we can't track the integer. */
&& POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND
(TREE_OPERAND (stmt, 1), 0)))
&& !POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (stmt, 1))))
- return true;
+ return ESCAPE_BAD_CAST;
/* If the LHS is an SSA name, it can't possibly represent a non-local
memory store. */
if (TREE_CODE (lhs) == SSA_NAME)
- return false;
+ return NO_ESCAPE;
/* FIXME: LHS is not an SSA_NAME. Even if it's an assignment to a
local variables we cannot be sure if it will escape, because we
Midkiff, ``Escape analysis for java,'' in Proceedings of the
Conference on Object-Oriented Programming Systems, Languages, and
Applications (OOPSLA), pp. 1-19, 1999. */
- return true;
+ return ESCAPE_STORED_IN_GLOBAL;
}
else if (TREE_CODE (stmt) == RETURN_EXPR)
- return true;
+ return ESCAPE_TO_RETURN;
- return false;
+ return NO_ESCAPE;
}
/* Create a new memory tag of type TYPE.
if (tag == NULL_TREE)
tag = create_memory_tag (TREE_TYPE (TREE_TYPE (ptr)), false);
-
- /* If PTR is a PARM_DECL, it points to a global variable or malloc,
- then its name tag should be considered a global variable. */
- if (TREE_CODE (SSA_NAME_VAR (ptr)) == PARM_DECL
- || pi->pt_global_mem)
- mark_call_clobbered (tag);
-
return tag;
}
TREE_THIS_VOLATILE (global_var) = 0;
TREE_ADDRESSABLE (global_var) = 0;
+ create_var_ann (global_var);
+ mark_call_clobbered (global_var, ESCAPE_UNKNOWN);
add_referenced_tmp_var (global_var);
mark_sym_for_renaming (global_var);
}
/* Array for building all the v_must_def operands. */
static VEC(tree,heap) *build_v_must_defs;
-/* True if the operands for call clobbered vars are cached and valid. */
-bool ssa_call_clobbered_cache_valid;
-bool ssa_ro_call_cache_valid;
/* These arrays are the cached operand vectors for call clobbered calls. */
-static VEC(tree,heap) *clobbered_v_may_defs;
-static VEC(tree,heap) *clobbered_vuses;
-static VEC(tree,heap) *ro_call_vuses;
static bool ops_active = false;
static GTY (()) struct ssa_operand_memory_d *operand_memory = NULL;
static void append_v_may_def (tree);
static void append_v_must_def (tree);
static void add_call_clobber_ops (tree, tree);
-static void add_call_read_ops (tree);
+static void add_call_read_ops (tree, tree);
static void add_stmt_operand (tree *, stmt_ann_t, int);
static void build_ssa_operands (tree stmt);
return ops_active;
}
+/* Structure storing statistics on how many call clobbers we have, and
+ how many where avoided. */
+static struct
+{
+ /* Number of call-clobbered ops we attempt to add to calls in
+ add_call_clobber_ops. */
+ unsigned int clobbered_vars;
+
+ /* Number of write-clobbers (v_may_defs) avoided by using
+ not_written information. */
+ unsigned int static_write_clobbers_avoided;
+
+ /* Number of reads (vuses) avoided by using not_read
+ information. */
+ unsigned int static_read_clobbers_avoided;
+
+ /* Number of write-clobbers avoided because the variable can't escape to
+ this call. */
+ unsigned int unescapable_clobbers_avoided;
+ /* Number of readonly uses we attempt to add to calls in
+ add_call_read_ops. */
+ unsigned int readonly_clobbers;
+
+ /* Number of readonly uses we avoid using not_read information. */
+ unsigned int static_readonly_clobbers_avoided;
+} clobber_stats;
+
/* Initialize the operand cache routines. */
void
gcc_assert (operand_memory == NULL);
operand_memory_index = SSA_OPERAND_MEMORY_SIZE;
ops_active = true;
+ memset (&clobber_stats, 0, sizeof (clobber_stats));
+
}
ggc_free (ptr);
}
- VEC_free (tree, heap, clobbered_v_may_defs);
- VEC_free (tree, heap, clobbered_vuses);
- VEC_free (tree, heap, ro_call_vuses);
ops_active = false;
+
+ if (dump_file && (dump_flags & TDF_STATS))
+ {
+ fprintf (dump_file, "Original clobbered vars:%d\n", clobber_stats.clobbered_vars);
+ fprintf (dump_file, "Static write clobbers avoided:%d\n", clobber_stats.static_write_clobbers_avoided);
+ fprintf (dump_file, "Static read clobbers avoided:%d\n", clobber_stats.static_read_clobbers_avoided);
+ fprintf (dump_file, "Unescapable clobbers avoided:%d\n", clobber_stats.unescapable_clobbers_avoided);
+ fprintf (dump_file, "Original readonly clobbers:%d\n", clobber_stats.readonly_clobbers);
+ fprintf (dump_file, "Static readonly clobbers avoided:%d\n", clobber_stats.static_readonly_clobbers_avoided);
+ }
}
&& !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
add_call_clobber_ops (stmt, get_callee_fndecl (expr));
else if (!(call_flags & ECF_CONST))
- add_call_read_ops (stmt);
+ add_call_read_ops (stmt, get_callee_fndecl (expr));
}
/* Find uses in the called function. */
}
}
-
/* Add clobbering definitions for .GLOBAL_VAR or for each of the call
clobbered variables in the function. */
add_call_clobber_ops (tree stmt, tree callee)
{
unsigned u;
- tree t;
bitmap_iterator bi;
stmt_ann_t s_ann = stmt_ann (stmt);
- struct stmt_ann_d empty_ann;
bitmap not_read_b, not_written_b;
-
+
/* Functions that are not const, pure or never return may clobber
call-clobbered variables. */
if (s_ann)
return;
}
- /* FIXME - if we have better information from the static vars
- analysis, we need to make the cache call site specific. This way
- we can have the performance benefits even if we are doing good
- optimization. */
-
/* Get info for local and module level statics. There is a bit
set for each static if the call being processed does not read
or write that variable. */
not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
not_written_b = callee ? ipa_reference_get_not_written_global (callee) : NULL;
-
- /* If cache is valid, copy the elements into the build vectors. */
- if (ssa_call_clobbered_cache_valid
- && (!not_read_b || bitmap_empty_p (not_read_b))
- && (!not_written_b || bitmap_empty_p (not_written_b)))
- {
- for (u = 0 ; u < VEC_length (tree, clobbered_vuses); u++)
- {
- t = VEC_index (tree, clobbered_vuses, u);
- gcc_assert (TREE_CODE (t) != SSA_NAME);
- var_ann (t)->in_vuse_list = 1;
- VEC_safe_push (tree, heap, build_vuses, (tree)t);
- }
- for (u = 0; u < VEC_length (tree, clobbered_v_may_defs); u++)
- {
- t = VEC_index (tree, clobbered_v_may_defs, u);
- gcc_assert (TREE_CODE (t) != SSA_NAME);
- var_ann (t)->in_v_may_def_list = 1;
- VEC_safe_push (tree, heap, build_v_may_defs, (tree)t);
- }
- return;
- }
-
- memset (&empty_ann, 0, sizeof (struct stmt_ann_d));
-
/* Add a V_MAY_DEF operand for every call clobbered variable. */
EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, u, bi)
{
- tree var = referenced_var (u);
- unsigned int uid = u;
+ tree var = referenced_var_lookup (u);
+ unsigned int escape_mask = var_ann (var)->escape_mask;
+ tree real_var = var;
+ bool not_read;
+ bool not_written;
+
+ /* Not read and not written are computed on regular vars, not
+ subvars, so look at the parent var if this is an SFT. */
- if (unmodifiable_var_p (var))
- add_stmt_operand (&var, &empty_ann, opf_none);
- else
+ if (TREE_CODE (var) == STRUCT_FIELD_TAG)
+ real_var = SFT_PARENT_VAR (var);
+
+ not_read = not_read_b ? bitmap_bit_p (not_read_b,
+ DECL_UID (real_var)) : false;
+ not_written = not_written_b ? bitmap_bit_p (not_written_b,
+ DECL_UID (real_var)) : false;
+ gcc_assert (!unmodifiable_var_p (var));
+
+ clobber_stats.clobbered_vars++;
+
+ /* See if this variable is really clobbered by this function. */
+
+ /* Trivial case: Things escaping only to pure/const are not
+ clobbered by non-pure-const, and only read by pure/const. */
+ if ((escape_mask & ~(ESCAPE_TO_PURE_CONST)) == 0)
{
- bool not_read;
- bool not_written;
-
- /* Not read and not written are computed on regular vars, not
- subvars, so look at the parent var if this is an SFT. */
-
- if (TREE_CODE (var) == STRUCT_FIELD_TAG)
- uid = DECL_UID (SFT_PARENT_VAR (var));
-
- not_read =
- not_read_b ? bitmap_bit_p (not_read_b, uid) : false;
- not_written =
- not_written_b ? bitmap_bit_p (not_written_b, uid) : false;
-
- if (not_written)
+ tree call = get_call_expr_in (stmt);
+ if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
{
- if (!not_read)
- add_stmt_operand (&var, &empty_ann, opf_none);
+ add_stmt_operand (&var, s_ann, opf_none);
+ clobber_stats.unescapable_clobbers_avoided++;
+ continue;
}
else
- add_stmt_operand (&var, &empty_ann, opf_is_def);
+ {
+ clobber_stats.unescapable_clobbers_avoided++;
+ continue;
+ }
}
+
+ if (not_written)
+ {
+ clobber_stats.static_write_clobbers_avoided++;
+ if (!not_read)
+ add_stmt_operand (&var, s_ann, opf_none);
+ else
+ clobber_stats.static_read_clobbers_avoided++;
+ }
+ else
+ add_stmt_operand (&var, s_ann, opf_is_def);
}
-
- if ((!not_read_b || bitmap_empty_p (not_read_b))
- && (!not_written_b || bitmap_empty_p (not_written_b)))
- {
- /* Prepare empty cache vectors. */
- VEC_truncate (tree, clobbered_vuses, 0);
- VEC_truncate (tree, clobbered_v_may_defs, 0);
-
- /* Now fill the clobbered cache with the values that have been found. */
- for (u = 0; u < VEC_length (tree, build_vuses); u++)
- VEC_safe_push (tree, heap, clobbered_vuses,
- VEC_index (tree, build_vuses, u));
-
- gcc_assert (VEC_length (tree, build_vuses)
- == VEC_length (tree, clobbered_vuses));
-
- for (u = 0; u < VEC_length (tree, build_v_may_defs); u++)
- VEC_safe_push (tree, heap, clobbered_v_may_defs,
- VEC_index (tree, build_v_may_defs, u));
-
- gcc_assert (VEC_length (tree, build_v_may_defs)
- == VEC_length (tree, clobbered_v_may_defs));
-
- ssa_call_clobbered_cache_valid = true;
- }
+
}
function. */
static void
-add_call_read_ops (tree stmt)
+add_call_read_ops (tree stmt, tree callee)
{
unsigned u;
- tree t;
bitmap_iterator bi;
stmt_ann_t s_ann = stmt_ann (stmt);
- struct stmt_ann_d empty_ann;
+ bitmap not_read_b;
/* if the function is not pure, it may reference memory. Add
a VUSE for .GLOBAL_VAR if it has been created. See add_referenced_var
return;
}
- /* If cache is valid, copy the elements into the build vector. */
- if (ssa_ro_call_cache_valid)
- {
- for (u = 0; u < VEC_length (tree, ro_call_vuses); u++)
- {
- t = VEC_index (tree, ro_call_vuses, u);
- gcc_assert (TREE_CODE (t) != SSA_NAME);
- var_ann (t)->in_vuse_list = 1;
- VEC_safe_push (tree, heap, build_vuses, (tree)t);
- }
- return;
- }
-
- memset (&empty_ann, 0, sizeof (struct stmt_ann_d));
+ not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
/* Add a VUSE for each call-clobbered variable. */
EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, u, bi)
{
tree var = referenced_var (u);
- add_stmt_operand (&var, &empty_ann, opf_none | opf_non_specific);
- }
-
- /* Prepare empty cache vectors. */
- VEC_truncate (tree, ro_call_vuses, 0);
+ tree real_var = var;
+ bool not_read;
+
+ clobber_stats.readonly_clobbers++;
- /* Now fill the clobbered cache with the values that have been found. */
- for (u = 0; u < VEC_length (tree, build_vuses); u++)
- VEC_safe_push (tree, heap, ro_call_vuses,
- VEC_index (tree, build_vuses, u));
+ /* Not read and not written are computed on regular vars, not
+ subvars, so look at the parent var if this is an SFT. */
- gcc_assert (VEC_length (tree, build_vuses)
- == VEC_length (tree, ro_call_vuses));
+ if (TREE_CODE (var) == STRUCT_FIELD_TAG)
+ real_var = SFT_PARENT_VAR (var);
- ssa_ro_call_cache_valid = true;
+ not_read = not_read_b ? bitmap_bit_p (not_read_b,
+ DECL_UID (real_var)) : false;
+
+ if (not_read)
+ {
+ clobber_stats.static_readonly_clobbers_avoided++;
+ continue;
+ }
+
+ add_stmt_operand (&var, s_ann, opf_none | opf_non_specific);
+ }
}
extern void debug_immediate_uses (void);
extern void debug_immediate_uses_for (tree var);
-extern bool ssa_call_clobbered_cache_valid;
-extern bool ssa_ro_call_cache_valid;
-
extern bool ssa_operands_active (void);
extern void add_to_addressable_set (tree, bitmap *);
bitmap addr_taken;
use_operand_p use_p;
ssa_op_iter iter;
- bool stmt_escapes_p = is_escape_site (stmt, ai);
+ enum escape_type stmt_escape_type = is_escape_site (stmt, ai);
tree op;
/* Mark all the variables whose address are taken by the statement. */
/* If STMT is an escape point, all the addresses taken by it are
call-clobbered. */
- if (stmt_escapes_p)
+ if (stmt_escape_type != NO_ESCAPE)
{
bitmap_iterator bi;
unsigned i;
EXECUTE_IF_SET_IN_BITMAP (addr_taken, 0, i, bi)
- mark_call_clobbered (referenced_var (i));
+ {
+ tree rvar = referenced_var (i);
+ if (!unmodifiable_var_p (rvar))
+ mark_call_clobbered (rvar, stmt_escape_type);
+ }
}
}
bitmap_set_bit (ai->dereferenced_ptrs_load, DECL_UID (var));
}
- if (stmt_escapes_p && num_derefs < num_uses)
+ if (stmt_escape_type != NO_ESCAPE && num_derefs < num_uses)
{
/* If STMT is an escape point and STMT contains at
least one direct use of OP, then the value of OP
escapes and so the pointed-to variables need to
be marked call-clobbered. */
pi->value_escapes_p = 1;
+ pi->escape_mask |= stmt_escape_type;
/* If the statement makes a function call, assume
that pointer OP will be dereferenced in a store
#define NUM_REFERENCES_SET(ANN, VAL) (ANN)->common.aux = (void*) ((void *)(VAL))
/* In tree-ssa-alias.c. */
-bool is_escape_site (tree, struct alias_info *);
+enum escape_type is_escape_site (tree, struct alias_info *);
/* In tree-ssa-structalias.c. */
extern void compute_points_to_sets (struct alias_info *);
git://gcc.gnu.org / gcc.git / commitdiff