On 03/19/2015 02:08 AM, Richard Biener wrote:
On Wed, Mar 18, 2015 at 10:28 PM, Jason Merrill <ja...@redhat.com> wrote:
If you move the call to rest_of_decl_compilation we could go through and
prune the debug info for unused decls at dwarf2out_finish time, the way we
do with unused types.
True. Note that the varpool nodes eventually get created once the
first use is seen.
So I wonder how much garbage we create by unconditionally creating the node
in rest_of_decl_compilation (yeah, header files, of course - probably
a similar issue
for unused function declarations?).
I'd prefer to do early_global_decl from rest_of_decl_compilation (and shun the
symtab/varpool walk - but that would require the FEs would hand off each global
that possibly needs debug info through rest_of_decl_compilation).
To prune globals during early(!) dwarf2out_finish you should be able to use the
symbol table (not sure if we prune all unused symbols, but surely the list
of references should be empty).
Richard.
Thank you both.
I have moved the debug early generation for _symbols_ to
rest_of_decl_compilation. I'm not so so brave as to move
FUNCTION_DECL's and such. Besides, things are working fine. Let me get
through the rest of my gdb regressions. :).
I am now running gdb tests for every patch, in an effort to fix the
plethora of regressions I have caused over the past few months. The
current patch exposes no regressions for guality.exp, or for the gdb
testsuite. For that matter, it fixes 4-5 gdb regressions.
I will prune the unused DIEs in a subsequent patch; actually much later,
when I'm done regression hunting.
Let me know if you have any problems with this. I am committing to the
branch.
Aldy
commit b1457fad19257267facddb6ce88c6041a24a5154
Author: Aldy Hernandez <al...@redhat.com>
Date: Thu Mar 19 10:21:02 2015 -0700
Unconditionally send all global symbols (whether used or not) to
early_global_decl.
diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 1650c6c..e60acd5 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -2430,16 +2430,6 @@ symbol_table::finalize_compilation_unit (void)
if (flag_dump_passes)
dump_passes ();
- /* Generate early debug for global symbols. Any local symbols will
- be handled by either handling reachable functions further down
- (and by consequence, locally scoped symbols), or by generating
- DIEs for types. */
- symtab_node *snode;
- FOR_EACH_SYMBOL (snode)
- if (TREE_CODE (snode->decl) != FUNCTION_DECL
- && !decl_function_context (snode->decl))
- (*debug_hooks->early_global_decl) (snode->decl);
-
/* Gimplify and lower all functions, compute reachability and
remove unreachable nodes. */
analyze_functions ();
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 92f4903..76fd70b 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -21868,17 +21868,6 @@ dwarf2out_decl (tree decl)
break;
case VAR_DECL:
- /* Ignore this VAR_DECL if it refers to a file-scope extern data object
- declaration and if the declaration was never even referenced from
- within this entire compilation unit. We suppress these DIEs in
- order to save space in the .debug section (by eliminating entries
- which are probably useless). Note that we must not suppress
- block-local extern declarations (whether used or not) because that
- would screw-up the debugger's name lookup mechanism and cause it to
- miss things which really ought to be in scope at a given point. */
- if (DECL_EXTERNAL (decl) && !TREE_USED (decl))
- return NULL;
-
/* For local statics lookup proper context die. */
if (local_function_static (decl))
context_die = lookup_decl_die (DECL_CONTEXT (decl));
@@ -25110,6 +25099,8 @@ dwarf2out_finish (const char *filename)
if (flag_eliminate_unused_debug_types)
prune_unused_types ();
+ /* FIXME: Prune DIEs for unused decls. */
+
/* Generate separate COMDAT sections for type DIEs. */
if (use_debug_types)
{
diff --git a/gcc/passes.c b/gcc/passes.c
index 3a16768..ce06035 100644
--- a/gcc/passes.c
+++ b/gcc/passes.c
@@ -293,11 +293,16 @@ rest_of_decl_compilation (tree decl,
&& TREE_STATIC (decl))
varpool_node::get_create (decl);
- /* ?? Theoretically, we should be able to to call
- debug_hooks->early_global_decl() here just as we do for
- rest_of_type_compilation below. This would require changing how
- we're currently calling early_global_decl() in all the
- front-ends. Something to look into later. */
+ /* Generate early debug for global symbols. Any local symbols will
+ be handled by either handling reachable functions from
+ finalize_compilation_unit (and by consequence, locally scoped
+ symbols), or by rest_of_type_compilation below. */
+ if (!flag_wpa
+ && TREE_CODE (decl) != FUNCTION_DECL
+ && !decl_function_context (decl)
+ && !current_function_decl
+ && !decl_type_context (decl))
+ (*debug_hooks->early_global_decl) (decl);
}
/* Called after finishing a record, union or enumeral type. */
