PATCH: Shrinking C++ front end data structures
Doug Gregor
doug.gregor@gmail.com
Mon Mar 12 18:13:00 GMT 2007
[My apologies for the empty e-mails earlier; I'll try again]
The variadic templates patch introduced a significant compile-time
memory usage regression due to the addition to two boolean flags:
http://gcc.gnu.org/ml/gcc-patches/2007-03/msg00652.html
The attached patch uses existing bits for these two flags, to bring
our memory usage back where it was. In addition, this patch attacks
some low-hanging fruit in the C++ data structures, packing values into
single bits when possible and making some HOST_WIDE_INTs into smaller
ints (where the HOST_WIDE_INTs aren't needed).
On the tramp3d test on i686-pc-linux-gnu, total virtual memory drops
from 437001kB down to 432961kB.
Tested i686-pc-linux-gnu; no regressions.
Okay for mainline?
Cheers,
Doug
2007-03-12 Douglas Gregor <doug.gregor@gmail.com>
* ptree.c (cxx_print_type): Use formatting markup for integers
when printing template parameter index/level/orig level.
(cxx_print_xnode): Ditto.
* cp-tree.h (TEMPLATE_PARM_PARAMETER_PACK): Use TREE_LANG_FLAG_0.
(struct template_parm_index_s): Remove the PARAMETER_PACK member.
Make INDEX, LEVEL, and ORIG_LEVEL integers instead of
HOST_WIDE_INTs.
(struct saved_scope): Make X_PROCESSING_TEMPLATE_DECL an int,
rather than a HOST_WIDE_INT.
Turn X_PROCESSING_EXPLICIT_INSTANTIATION, SKIP_EVALUATION, and
NEED_POP_FUNCTION_CONTEXT into bool bitfields; reorder fields for
better bit-packing.
(struct language_function): Make RETURNS_VALUE, RETURNS_NULL,
RETURNS_ABNORMALLY, IN_FUNCTION_TRY_HANDLER, and
IN_BASE_INITIALIZER single-bit bitfields.
(struct cp_declarator): Make KIND a 4-bit field. Move
PARAMETER_PACK_P just after KIND.
* name-lookup.c (push_to_top_level): Make need_pop a bool value.
Index: ptree.c
===================================================================
--- ptree.c (revision 122840)
+++ ptree.c (working copy)
@@ -68,8 +68,7 @@ cxx_print_type (FILE *file, tree node, i
case TEMPLATE_TEMPLATE_PARM:
case BOUND_TEMPLATE_TEMPLATE_PARM:
indent_to (file, indent + 3);
- fprintf (file, "index " HOST_WIDE_INT_PRINT_DEC " level "
- HOST_WIDE_INT_PRINT_DEC " orig_level " HOST_WIDE_INT_PRINT_DEC,
+ fprintf (file, "index %d level %d orig_level %d",
TEMPLATE_TYPE_IDX (node), TEMPLATE_TYPE_LEVEL (node),
TEMPLATE_TYPE_ORIG_LEVEL (node));
return;
@@ -181,8 +180,7 @@ cxx_print_xnode (FILE *file, tree node,
break;
case TEMPLATE_PARM_INDEX:
indent_to (file, indent + 3);
- fprintf (file, "index " HOST_WIDE_INT_PRINT_DEC " level "
- HOST_WIDE_INT_PRINT_DEC " orig_level " HOST_WIDE_INT_PRINT_DEC,
+ fprintf (file, "index %d level %d orig_level %d",
TEMPLATE_PARM_IDX (node), TEMPLATE_PARM_LEVEL (node),
TEMPLATE_PARM_ORIG_LEVEL (node));
break;
Index: cp-tree.h
===================================================================
--- cp-tree.h (revision 122840)
+++ cp-tree.h (working copy)
@@ -56,6 +56,7 @@ struct diagnostic_context;
OMP_FOR_GIMPLIFYING_P (in OMP_FOR)
BASELINK_QUALIFIED_P (in BASELINK)
TARGET_EXPR_IMPLICIT_P (in TARGET_EXPR)
+ TEMPLATE_PARM_PARAMETER_PACK (in TEMPLATE_PARM_INDEX)
1: IDENTIFIER_VIRTUAL_P (in IDENTIFIER_NODE)
TI_PENDING_TEMPLATE_FLAG.
TEMPLATE_PARMS_FOR_INLINE.
@@ -219,14 +220,10 @@ struct lang_identifier GTY(())
struct template_parm_index_s GTY(())
{
struct tree_common common;
- HOST_WIDE_INT index;
- HOST_WIDE_INT level;
- HOST_WIDE_INT orig_level;
+ int index;
+ int level;
+ int orig_level;
tree decl;
-
- /* When true, indicates that this parameter is actually a parameter
- pack, for variadic templates. */
- BOOL_BITFIELD parameter_pack;
};
typedef struct template_parm_index_s template_parm_index;
@@ -703,11 +700,12 @@ struct saved_scope GTY(())
struct cp_binding_level *x_previous_class_level;
tree x_saved_tree;
- HOST_WIDE_INT x_processing_template_decl;
+ int x_processing_template_decl;
int x_processing_specialization;
- bool x_processing_explicit_instantiation;
- int need_pop_function_context;
- bool skip_evaluation;
+
+ BOOL_BITFIELD need_pop_function_context;
+ BOOL_BITFIELD x_processing_explicit_instantiation;
+ BOOL_BITFIELD skip_evaluation;
struct stmt_tree_s x_stmt_tree;
@@ -786,11 +784,11 @@ struct language_function GTY(())
tree x_vtt_parm;
tree x_return_value;
- int returns_value;
- int returns_null;
- int returns_abnormally;
- int in_function_try_handler;
- int in_base_initializer;
+ unsigned returns_value : 1;
+ unsigned returns_null : 1;
+ unsigned returns_abnormally : 1;
+ unsigned in_function_try_handler : 1;
+ unsigned in_base_initializer : 1;
/* True if this function can throw an exception. */
BOOL_BITFIELD can_throw : 1;
@@ -3705,7 +3703,7 @@ enum overload_flags { NO_SPECIAL = 0, DT
#define TEMPLATE_PARM_DESCENDANTS(NODE) (TREE_CHAIN (NODE))
#define TEMPLATE_PARM_ORIG_LEVEL(NODE) (TEMPLATE_PARM_INDEX_CAST
(NODE)->orig_level)
#define TEMPLATE_PARM_DECL(NODE) (TEMPLATE_PARM_INDEX_CAST (NODE)->decl)
-#define TEMPLATE_PARM_PARAMETER_PACK(NODE) (TEMPLATE_PARM_INDEX_CAST
(NODE)->parameter_pack)
+#define TEMPLATE_PARM_PARAMETER_PACK(NODE) (TREE_LANG_FLAG_0
(TEMPLATE_PARM_INDEX_CHECK (NODE)))
/* These macros are for accessing the fields of TEMPLATE_TYPE_PARM,
TEMPLATE_TEMPLATE_PARM and BOUND_TEMPLATE_TEMPLATE_PARM nodes. */
@@ -3901,16 +3899,18 @@ struct cp_parameter_declarator {
/* A declarator. */
struct cp_declarator {
/* The kind of declarator. */
- cp_declarator_kind kind;
+ ENUM_BITFIELD (cp_declarator_kind) kind : 4;
+ /* Whether we parsed an ellipsis (`...') just before the declarator,
+ to indicate this is a parameter pack. */
+ BOOL_BITFIELD parameter_pack_p : 1;
+ /* Sparse bits to pad out a 32-bit word. */
+ unsigned spare : 27;
/* Attributes that apply to this declarator. */
tree attributes;
/* For all but cdk_id and cdk_error, the contained declarator. For
cdk_id and cdk_error, guaranteed to be NULL. */
cp_declarator *declarator;
location_t id_loc; /* Currently only set for cdk_id. */
- /* Whether we parsed an ellipsis (`...') just before the declarator,
- to indicate this is a parameter pack. */
- bool parameter_pack_p;
union {
/* For identifiers. */
struct {
Index: name-lookup.c
===================================================================
--- name-lookup.c (revision 122840)
+++ name-lookup.c (working copy)
@@ -5030,7 +5030,7 @@ push_to_top_level (void)
struct cp_binding_level *b;
cxx_saved_binding *sb;
size_t i;
- int need_pop;
+ bool need_pop;
timevar_push (TV_NAME_LOOKUP);
s = GGC_CNEW (struct saved_scope);
@@ -5040,11 +5040,11 @@ push_to_top_level (void)
/* If we're in the middle of some function, save our state. */
if (cfun)
{
- need_pop = 1;
+ need_pop = true;
push_function_context_to (NULL_TREE);
}
else
- need_pop = 0;
+ need_pop = false;
if (scope_chain && previous_class_level)
store_class_bindings (previous_class_level->class_shadowed,
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