On Tue, 10 Apr 2012, Jan Hubicka wrote:
> Hi,
> this is very basis of the symbol table work. The basic idea is:
>
> 1) give cgraph node and varpool node common base (symtab node)
> 2) Move common data there: that is type, declaration, visibility flags,
> force_output, ipa references and other stuff.
> 3) Introduce symtab.c for basic symbol table manipulation that in first run
> is represented as simple linked list of cgraph/varpool node entries.
> 4) Update ipa-reference API for the new class structure
> 5) Significantly clanup/rework old cgraph reachability and construction code
> that has grown up very convoluted to meet non-unit-at-a-time needs.
> Merge most of logic done on varpool and cgraph into common grounds
> 6) reorg WHOPR partitioning code
> 7) Add new types of symbol table entries - labels, aliases and possibly
> constant pools and symbols defined by asm statements so existing WHOPR bugs
> have chance to be solved.
> 8) Add actual symbol name hash - this is trickier than it sounds given that
> GCC currently don't really know the symbol names on non-LTO targets.
> I plan to simply take the existing lto-symtab logic and slowly require
> targtets to provide hook to translate ASSEMBLER_NAME into symbol name.
> It would be nice to get rid of ASSEMBLER_NAME and replace it by SYMBOL_NAME
> + set of flags, but this is very hard to do since assembler name goes
> everywhere into target machinery. I am not really volunteering to do that
> at this moment.
> 9) Reorg most of lto-symtab to work on symtab keeping the prevailing and
> other stuff there.
>
> I would like to get most of the changes into mainline for this stage1. In
> worst
> case at least 1-6.
>
> I prototytped all except for lto-symtab reorg, but I would like to re-do
> everything incrementally for mainline with cleanups on the way. Many
> of things can be significantly simplified over current implementation
> and I hope it will make it easier to follow the changes and get me some useful
> feedback. It is kind of second chance for cleaner cgraph API and it would
> be nice to get it mostly right.
>
> This patch takes the very first step by adding the base object. It implements
> inheritance in C via cgraph/varpool accessors. C++ would make sense here, but
> I
> think I still can't because of gengtype. Once C++ is not only allowed, but
> also useful, I don't think changing the syntactical shugar to actual classes
> would be a significant project.
I agree. I hope we get to 8), as lto-symtab requires that ;)
This is ok.
Thanks for finally pushing this,
Richard.
> Honza
>
> * cgraph.h: Remove misledaing comment on ipa-ref.h.
> (symtab_type): New enum.
> (symtab_node): New structure.
> (cgraph_node, varpool_node): Add symbol base type.
> (cgraph, varpool): New accestor functions.
> * cgraph.c (cgraph_create_node_1): Set symbol type.
> * varpool.c (varpool_node): Set symbol type.
> Index: cgraph.h
> ===================================================================
> --- cgraph.h (revision 186252)
> +++ cgraph.h (working copy)
> @@ -27,7 +27,23 @@ along with GCC; see the file COPYING3.
> #include "tree.h"
> #include "basic-block.h"
> #include "function.h"
> -#include "ipa-ref.h" /* FIXME: inappropriate dependency of cgraph on IPA. */
> +#include "ipa-ref.h"
> +
> +/* Symbol table consists of functions and variables.
> + TODO: add labels, constant pool and aliases. */
> +enum symtab_type
> +{
> + SYMTAB_FUNCTION,
> + SYMTAB_VARIABLE
> +};
> +
> +/* Base of all entries in the symbol table.
> + The symtab_node is inherited by cgraph and varpol nodes. */
> +struct GTY(()) symtab_node
> +{
> + /* Type of the symbol. */
> + enum symtab_type type;
> +};
>
> enum availability
> {
> @@ -150,6 +166,7 @@ struct GTY(()) cgraph_clone_info
> Each function decl has assigned cgraph_node listing callees and callers.
> */
>
> struct GTY((chain_next ("%h.next"), chain_prev ("%h.previous"))) cgraph_node
> {
> + struct symtab_node symbol;
> tree decl;
> struct cgraph_edge *callees;
> struct cgraph_edge *callers;
> @@ -387,6 +404,7 @@ DEF_VEC_ALLOC_P(cgraph_edge_p,heap);
> Each static variable decl has assigned varpool_node. */
>
> struct GTY((chain_next ("%h.next"), chain_prev ("%h.prev"))) varpool_node {
> + struct symtab_node symbol;
> tree decl;
> /* For aliases points to declaration DECL is alias of. */
> tree alias_of;
> @@ -688,6 +706,23 @@ void varpool_add_new_variable (tree);
> #define FOR_EACH_STATIC_VARIABLE(node) \
> for ((node) = varpool_nodes_queue; (node); (node) = (node)->next_needed)
>
> +/* Return callgraph node for given symbol and check it is a function. */
> +static inline struct cgraph_node *
> +cgraph (struct symtab_node *node)
> +{
> + gcc_checking_assert (node->type == SYMTAB_FUNCTION);
> + return (struct cgraph_node *)node;
> +}
> +
> +/* Return varpool node for given symbol and check it is a variable. */
> +static inline struct varpool_node *
> +varpool (struct symtab_node *node)
> +{
> + gcc_checking_assert (node->type == SYMTAB_FUNCTION);
> + return (struct varpool_node *)node;
> +}
> +
> +
> /* Return first reachable static variable with initializer. */
> static inline struct varpool_node *
> varpool_first_static_initializer (void)
> Index: cgraph.c
> ===================================================================
> --- cgraph.c (revision 186252)
> +++ cgraph.c (working copy)
> @@ -473,6 +473,7 @@ cgraph_create_node_1 (void)
> {
> struct cgraph_node *node = cgraph_allocate_node ();
>
> + node->symbol.type = SYMTAB_FUNCTION;
> node->next = cgraph_nodes;
> node->order = cgraph_order++;
> if (cgraph_nodes)
> Index: varpool.c
> ===================================================================
> --- varpool.c (revision 186252)
> +++ varpool.c (working copy)
> @@ -142,6 +142,7 @@ varpool_node (tree decl)
> if (*slot)
> return *slot;
> node = ggc_alloc_cleared_varpool_node ();
> + node->symbol.type = SYMTAB_VARIABLE;
> node->decl = decl;
> node->order = cgraph_order++;
> node->next = varpool_nodes;
>
>
--
Richard Guenther <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer
