Hi guys!
Despite what Go thinks:
/* The debug hooks are used to implement -fdump-go-spec because it
gives a simple and stable API for all the information we need to
dump. */
...the debug hooks are not stable... :).
The godump-1.c test is failing in the debug-early branch. It seems that
Go is hijacking the debug_hook machinery to access globals generated by
the front-ends. In debug-early, things have moved around.
With this patch I have done my best to give Go what it wants without
recreating what the front-ends were doing. I've made the go_decl() call
work from within the early_global_decl() hook which gets called as we
parse (rest_of_decl_compilation). I far as I understand, this hack is a
one-time thing for use internally in the build process, so we don't care
whether go_decl() will receive location information??
I have also relaxed the condition in rest_of_decl_compilation to allow
function prototypes. Go was expecting to be fed function prototypes as
part of the global_decl machinery. However, it won't ever see these, as
the early_global_decl code iterating through functions uses the symbol
table, which does not have prototypes:
/* Emit early debug for reachable functions, and by consequence,
locally scoped symbols. */
struct cgraph_node *cnode;
FOR_EACH_FUNCTION_WITH_GIMPLE_BODY (cnode)
if (!decl_function_context (cnode->decl))
(*debug_hooks->early_global_decl) (cnode->decl);
(By the way, even iterating through symbols, without regards to gimple
body, we end up with nothing...and even before we analyze_functions()
and prune unreachable nodes.).
Relaxing the condition does the trick, and the dwarf early_global_decl
debug hook just works because it avoids functions with no body anyhow.
In a world with Go and non dwarf (stabs, etc) debug hooks, I may have to
adjust the calls to debug_hooks->{early,late}_global_decl a bit more to
get all debugging backends to get what they want. This may involve
feeding more to the debug hooks while making the individual hooks
disregard DECLs they don't want/need.
Is there not a more modern way of Go getting the DECLs it needs without
abusing the debug_hook machinery?
Anyways... this is what I have so far. It may change, as I have at
least one stabs problem that may regarding tweaking things again.
Committed to branch.
Aldy
commit 040d95e2436d7fa1ef75761dfe50b7481726373d
Author: Aldy Hernandez <al...@redhat.com>
Date: Wed Apr 29 17:37:21 2015 -0700
Fix -fdump-go-spec.
diff --git a/gcc/godump.c b/gcc/godump.c
index 94d0c8b..5de34db 100644
--- a/gcc/godump.c
+++ b/gcc/godump.c
@@ -517,6 +517,7 @@ go_function_decl (tree decl)
static void
go_early_global_decl (tree decl)
{
+ go_decl (decl);
real_debug_hooks->early_global_decl (decl);
}
@@ -526,7 +527,6 @@ static void
go_late_global_decl (tree decl)
{
real_debug_hooks->late_global_decl (decl);
- go_decl (decl);
}
/* A type declaration. */
diff --git a/gcc/passes.c b/gcc/passes.c
index 3bb0e5d..4dee8ad 100644
--- a/gcc/passes.c
+++ b/gcc/passes.c
@@ -297,10 +297,20 @@ rest_of_decl_compilation (tree decl,
/* Generate early debug for global variables. Any local variables 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. */
+ symbols), or by rest_of_type_compilation below.
+
+ Also, pick up function prototypes, which will be mostly ignored
+ by the different early_global_decl() hooks, but will at least be
+ used by Go's hijack of the debug_hooks to implement
+ -fdump-go-spec. */
if (!flag_wpa
&& !in_lto_p
- && TREE_CODE (decl) != FUNCTION_DECL
+ && (TREE_CODE (decl) != FUNCTION_DECL
+ /* This will pick up function prototypes with no bodies,
+ which are not visible in finalize_compilation_unit()
+ while iterating with FOR_EACH_*_FUNCTION through the
+ symbol table. */
+ || !DECL_SAVED_TREE (decl))
&& !decl_function_context (decl)
&& !current_function_decl
&& !decl_type_context (decl))
