/* Liveness for SSA trees.
- Copyright (C) 2003, 2004, 2005, 2007, 2008 Free Software Foundation,
+ Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009 Free Software Foundation,
Inc.
Contributed by Andrew MacLeod <amacleod@redhat.com>
map = (var_map) xmalloc (sizeof (struct _var_map));
map->var_partition = partition_new (size);
- map->partition_to_var
- = (tree *)xmalloc (size * sizeof (tree));
- memset (map->partition_to_var, 0, size * sizeof (tree));
map->partition_to_view = NULL;
map->view_to_partition = NULL;
delete_var_map (var_map map)
{
var_map_base_fini (map);
- free (map->partition_to_var);
partition_delete (map->var_partition);
if (map->partition_to_view)
free (map->partition_to_view);
var_union (var_map map, tree var1, tree var2)
{
int p1, p2, p3;
- tree root_var = NULL_TREE;
- tree other_var = NULL_TREE;
+
+ gcc_assert (TREE_CODE (var1) == SSA_NAME);
+ gcc_assert (TREE_CODE (var2) == SSA_NAME);
/* This is independent of partition_to_view. If partition_to_view is
on, then whichever one of these partitions is absorbed will never have a
dereference into the partition_to_view array any more. */
- if (TREE_CODE (var1) == SSA_NAME)
- p1 = partition_find (map->var_partition, SSA_NAME_VERSION (var1));
- else
- {
- p1 = var_to_partition (map, var1);
- if (map->view_to_partition)
- p1 = map->view_to_partition[p1];
- root_var = var1;
- }
-
- if (TREE_CODE (var2) == SSA_NAME)
- p2 = partition_find (map->var_partition, SSA_NAME_VERSION (var2));
- else
- {
- p2 = var_to_partition (map, var2);
- if (map->view_to_partition)
- p2 = map->view_to_partition[p2];
-
- /* If there is no root_var set, or it's not a user variable, set the
- root_var to this one. */
- if (!root_var || (DECL_P (root_var) && DECL_IGNORED_P (root_var)))
- {
- other_var = root_var;
- root_var = var2;
- }
- else
- other_var = var2;
- }
+ p1 = partition_find (map->var_partition, SSA_NAME_VERSION (var1));
+ p2 = partition_find (map->var_partition, SSA_NAME_VERSION (var2));
gcc_assert (p1 != NO_PARTITION);
gcc_assert (p2 != NO_PARTITION);
if (map->partition_to_view)
p3 = map->partition_to_view[p3];
- if (root_var)
- change_partition_var (map, root_var, p3);
- if (other_var)
- change_partition_var (map, other_var, p3);
-
return p3;
}
for (x = 0; x < map->partition_size; x++)
{
tmp = partition_find (map->var_partition, x);
- if (map->partition_to_var[tmp] != NULL_TREE && !bitmap_bit_p (used, tmp))
+ if (ssa_name (tmp) != NULL_TREE && is_gimple_reg (ssa_name (tmp))
+ && (!has_zero_uses (ssa_name (tmp))
+ || !SSA_NAME_IS_DEFAULT_DEF (ssa_name (tmp))))
bitmap_set_bit (used, tmp);
}
{
bitmap_iterator bi;
unsigned count, i, x, limit;
- tree var;
gcc_assert (selected);
{
map->partition_to_view[x] = i;
map->view_to_partition[i] = x;
- var = map->partition_to_var[x];
- /* If any one of the members of a partition is not an SSA_NAME, make
- sure it is the representative. */
- if (TREE_CODE (var) != SSA_NAME)
- change_partition_var (map, var, i);
i++;
}
gcc_assert (i == count);
}
-/* This function is used to change the representative variable in MAP for VAR's
- partition to a regular non-ssa variable. This allows partitions to be
- mapped back to real variables. */
-
-void
-change_partition_var (var_map map, tree var, int part)
-{
- var_ann_t ann;
-
- gcc_assert (TREE_CODE (var) != SSA_NAME);
-
- ann = var_ann (var);
- ann->out_of_ssa_tag = 1;
- VAR_ANN_PARTITION (ann) = part;
- if (map->view_to_partition)
- map->partition_to_var[map->view_to_partition[part]] = var;
-}
-
-
static inline void mark_all_vars_used (tree *, void *data);
/* Helper function for mark_all_vars_used, called via walk_tree. */
next = &TREE_CHAIN (*t);
/* Debug info of nested function refers to the block of the
- function. */
+ function. We might stil call it even if all statements
+ of function it was nested into was elliminated.
+
+ TODO: We can actually look into cgraph to see if function
+ will be output to file. */
if (TREE_CODE (*t) == FUNCTION_DECL)
unused = false;
+ /* If a decl has a value expr, we need to instantiate it
+ regardless of debug info generation, to avoid codegen
+ differences in memory overlap tests. update_equiv_regs() may
+ indirectly call validate_equiv_mem() to test whether a
+ SET_DEST overlaps with others, and if the value expr changes
+ by virtual register instantiation, we may get end up with
+ different results. */
+ else if (TREE_CODE (*t) == VAR_DECL && DECL_HAS_VALUE_EXPR_P (*t))
+ unused = false;
+
+ /* Remove everything we don't generate debug info for. */
+ else if (DECL_IGNORED_P (*t))
+ {
+ *t = TREE_CHAIN (*t);
+ next = t;
+ }
+
/* When we are outputting debug info, we usually want to output
info about optimized-out variables in the scope blocks.
Exception are the scope blocks not containing any instructions
/* When we are not doing full debug info, we however can keep around
only the used variables for cfgexpand's memory packing saving quite
- a lot of memory. */
+ a lot of memory.
+
+ For sake of -g3, we keep around those vars but we don't count this as
+ use of block, so innermost block with no used vars and no instructions
+ can be considered dead. We only want to keep around blocks user can
+ breakpoint into and ask about value of optimized out variables.
+
+ Similarly we need to keep around types at least until all variables of
+ all nested blocks are gone. We track no information on whether given
+ type is used or not. */
+
else if (debug_info_level == DINFO_LEVEL_NORMAL
|| debug_info_level == DINFO_LEVEL_VERBOSE
/* Removing declarations before inlining is going to affect
DECL_UID that in turn is going to affect hashtables and
code generation. */
|| !cfun->after_inlining)
- unused = false;
-
+ ;
else
{
*t = TREE_CHAIN (*t);
{
tree next = BLOCK_CHAIN (*t);
tree supercontext = BLOCK_SUPERCONTEXT (*t);
+
*t = BLOCK_SUBBLOCKS (*t);
- gcc_assert (!BLOCK_CHAIN (*t));
+ while (BLOCK_CHAIN (*t))
+ {
+ BLOCK_SUPERCONTEXT (*t) = supercontext;
+ t = &BLOCK_CHAIN (*t);
+ }
BLOCK_CHAIN (*t) = next;
BLOCK_SUPERCONTEXT (*t) = supercontext;
t = &BLOCK_CHAIN (*t);
nsubblocks ++;
}
else
- {
- gcc_assert (!BLOCK_VARS (*t));
- *t = BLOCK_CHAIN (*t);
- }
+ *t = BLOCK_CHAIN (*t);
}
else
{
t = &BLOCK_CHAIN (*t);
nsubblocks ++;
}
+
+
+ if (!unused)
+ ;
/* Outer scope is always used. */
- if (!BLOCK_SUPERCONTEXT (scope)
- || TREE_CODE (BLOCK_SUPERCONTEXT (scope)) == FUNCTION_DECL)
+ else if (!BLOCK_SUPERCONTEXT (scope)
+ || TREE_CODE (BLOCK_SUPERCONTEXT (scope)) == FUNCTION_DECL)
unused = false;
- /* If there are more than one live subblocks, it is used. */
- else if (nsubblocks > 1)
+ /* Innermost blocks with no live variables nor statements can be always
+ eliminated. */
+ else if (!nsubblocks)
+ ;
+ /* If there are live subblocks and we still have some unused variables
+ or types declared, we must keep them.
+ Before inliing we must not depend on debug info verbosity to keep
+ DECL_UIDs stable. */
+ else if (!cfun->after_inlining && BLOCK_VARS (scope))
unused = false;
- /* When there is only one subblock, see if it is just wrapper we can
- ignore. Wrappers are not declaring any variables and not changing
- abstract origin. */
- else if (nsubblocks == 1
- && (BLOCK_VARS (scope)
- || ((debug_info_level == DINFO_LEVEL_NORMAL
- || debug_info_level == DINFO_LEVEL_VERBOSE)
- && ((BLOCK_ABSTRACT_ORIGIN (scope)
- != BLOCK_ABSTRACT_ORIGIN (BLOCK_SUPERCONTEXT (scope)))))))
+ /* For terse debug info we can eliminate info on unused variables. */
+ else if (debug_info_level == DINFO_LEVEL_NONE
+ || debug_info_level == DINFO_LEVEL_TERSE)
+ {
+ /* Even for -g0/-g1 don't prune outer scopes from artificial
+ functions, otherwise diagnostics using tree_nonartificial_location
+ will not be emitted properly. */
+ if (inlined_function_outer_scope_p (scope))
+ {
+ tree ao = scope;
+
+ while (ao
+ && TREE_CODE (ao) == BLOCK
+ && BLOCK_ABSTRACT_ORIGIN (ao) != ao)
+ ao = BLOCK_ABSTRACT_ORIGIN (ao);
+ if (ao
+ && TREE_CODE (ao) == FUNCTION_DECL
+ && DECL_DECLARED_INLINE_P (ao)
+ && lookup_attribute ("artificial", DECL_ATTRIBUTES (ao)))
+ unused = false;
+ }
+ }
+ else if (BLOCK_VARS (scope) || BLOCK_NUM_NONLOCALIZED_VARS (scope))
unused = false;
+ /* See if this block is important for representation of inlined function.
+ Inlined functions are always represented by block with
+ block_ultimate_origin being set to FUNCTION_DECL and DECL_SOURCE_LOCATION
+ set... */
+ else if (inlined_function_outer_scope_p (scope))
+ unused = false;
+ else
+ /* Verfify that only blocks with source location set
+ are entry points to the inlined functions. */
+ gcc_assert (BLOCK_SOURCE_LOCATION (scope) == UNKNOWN_LOCATION);
+
+ TREE_USED (scope) = !unused;
return unused;
}
}
+/* Dump scope blocks starting at SCOPE to FILE. INDENT is the
+ indentation level and FLAGS is as in print_generic_expr. */
+
+static void
+dump_scope_block (FILE *file, int indent, tree scope, int flags)
+{
+ tree var, t;
+ unsigned int i;
+
+ fprintf (file, "\n%*s{ Scope block #%i%s%s",indent, "" , BLOCK_NUMBER (scope),
+ TREE_USED (scope) ? "" : " (unused)",
+ BLOCK_ABSTRACT (scope) ? " (abstract)": "");
+ if (BLOCK_SOURCE_LOCATION (scope) != UNKNOWN_LOCATION)
+ {
+ expanded_location s = expand_location (BLOCK_SOURCE_LOCATION (scope));
+ fprintf (file, " %s:%i", s.file, s.line);
+ }
+ if (BLOCK_ABSTRACT_ORIGIN (scope))
+ {
+ tree origin = block_ultimate_origin (scope);
+ if (origin)
+ {
+ fprintf (file, " Originating from :");
+ if (DECL_P (origin))
+ print_generic_decl (file, origin, flags);
+ else
+ fprintf (file, "#%i", BLOCK_NUMBER (origin));
+ }
+ }
+ fprintf (file, " \n");
+ for (var = BLOCK_VARS (scope); var; var = TREE_CHAIN (var))
+ {
+ bool used = false;
+ var_ann_t ann;
+
+ if ((ann = var_ann (var))
+ && ann->used)
+ used = true;
+
+ fprintf (file, "%*s",indent, "");
+ print_generic_decl (file, var, flags);
+ fprintf (file, "%s\n", used ? "" : " (unused)");
+ }
+ for (i = 0; i < BLOCK_NUM_NONLOCALIZED_VARS (scope); i++)
+ {
+ fprintf (file, "%*s",indent, "");
+ print_generic_decl (file, BLOCK_NONLOCALIZED_VAR (scope, i),
+ flags);
+ fprintf (file, " (nonlocalized)\n");
+ }
+ for (t = BLOCK_SUBBLOCKS (scope); t ; t = BLOCK_CHAIN (t))
+ dump_scope_block (file, indent + 2, t, flags);
+ fprintf (file, "\n%*s}\n",indent, "");
+}
+
+
+/* Dump the tree of lexical scopes of current_function_decl to FILE.
+ FLAGS is as in print_generic_expr. */
+
+void
+dump_scope_blocks (FILE *file, int flags)
+{
+ dump_scope_block (file, 0, DECL_INITIAL (current_function_decl), flags);
+}
+
+
+/* Dump the tree of lexical scopes of current_function_decl to stderr.
+ FLAGS is as in print_generic_expr. */
+
+void
+debug_scope_blocks (int flags)
+{
+ dump_scope_blocks (stderr, flags);
+}
+
/* Remove local variables that are not referenced in the IL. */
void
var_ann_t ann;
bitmap global_unused_vars = NULL;
- if (optimize)
- mark_scope_block_unused (DECL_INITIAL (current_function_decl));
+ /* Removing declarations from lexical blocks when not optimizing is
+ not only a waste of time, it actually causes differences in stack
+ layout. */
+ if (!optimize)
+ return;
+
+ mark_scope_block_unused (DECL_INITIAL (current_function_decl));
/* Assume all locals are unused. */
FOR_EACH_REFERENCED_VAR (t, rvi)
{
gimple_stmt_iterator gsi;
size_t i;
+ edge_iterator ei;
+ edge e;
/* Walk the statements. */
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
mark_all_vars_used (&arg, NULL);
}
}
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ if (e->goto_locus)
+ TREE_USED (e->goto_block) = true;
}
+ cfun->has_local_explicit_reg_vars = false;
+
/* Remove unmarked local vars from local_decls. */
for (cell = &cfun->local_decls; *cell; )
{
continue;
}
}
+ else if (TREE_CODE (var) == VAR_DECL
+ && DECL_HARD_REGISTER (var)
+ && !is_global_var (var))
+ cfun->has_local_explicit_reg_vars = true;
cell = &TREE_CHAIN (*cell);
}
if (TREE_CODE (var) == VAR_DECL
&& is_global_var (var)
- && bitmap_bit_p (global_unused_vars, DECL_UID (var))
- && (optimize || DECL_ARTIFICIAL (var)))
+ && bitmap_bit_p (global_unused_vars, DECL_UID (var)))
*cell = TREE_CHAIN (*cell);
else
cell = &TREE_CHAIN (*cell);
pass is performed. */
FOR_EACH_REFERENCED_VAR (t, rvi)
if (!is_global_var (t)
- && !MTAG_P (t)
&& TREE_CODE (t) != PARM_DECL
&& TREE_CODE (t) != RESULT_DECL
&& !(ann = var_ann (t))->used
- && !ann->symbol_mem_tag
- && !TREE_ADDRESSABLE (t)
- && (optimize || DECL_ARTIFICIAL (t)))
+ && !ann->is_heapvar
+ && !TREE_ADDRESSABLE (t))
remove_referenced_var (t);
- if (optimize)
- remove_unused_scope_block_p (DECL_INITIAL (current_function_decl));
+ remove_unused_scope_block_p (DECL_INITIAL (current_function_decl));
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Scope blocks after cleanups:\n");
+ dump_scope_blocks (dump_file, dump_flags);
+ }
}
else
p = x;
- if (map->partition_to_var[p] == NULL_TREE)
+ if (ssa_name (p) == NULL_TREE)
continue;
t = 0;
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