Re: [PATCH] go/100537 - Bootstrap-O3 and bootstrap-debug fail

[guojiufu via Gcc-patches]

On 2021-05-14 15:39, guojiufu via Gcc-patches wrote:
On 2021-05-14 15:15, Richard Biener wrote:
On May 14, 2021 4:52:56 AM GMT+02:00, Jiufu Guo 
<guoji...@linux.ibm.com> wrote:
As discussed in the PR, Richard mentioned the method to
figure out which VAR was not set TREE_ADDRESSABLE, and
then cause this failure.  It is address_expression which
build addr_expr (build_fold_addr_expr_loc), but not set
TREE_ADDRESSABLE.
I drafted this patch with reference the comments from Richard
in this PR, while I'm not quite sure if more thing need to do.
So, please have review, thanks!

Bootstrap and regtest pass on ppc64le. Is this ok for trunk?

I suggest to use mark_addresssable unless we're sure expr is always an
entity where TREE_ADDRESSABLE has the desired meaning.

Thanks, Richard!
You point out the root concern, I'm not sure ;)

With looking at code "mark_addresssable" and code around 
tree-ssa.c:1013,
VAR_P, PARM_DECL, and RESULT_DECL are checked before accessing 
TREE_ADDRESSABLE.
So, just wondering if these entities need to be marked as 
TREE_ADDRESSABLE?

diff --git a/gcc/go/go-gcc.cc b/gcc/go/go-gcc.cc
index 5d9dbb5d068..85d324a92cc 100644
--- a/gcc/go/go-gcc.cc
+++ b/gcc/go/go-gcc.cc
@@ -1680,6 +1680,11 @@ Gcc_backend::address_expression(Bexpression* 
bexpr, Location location)
   if (expr == error_mark_node)
     return this->error_expression();

+  if ((VAR_P(expr)
+       || TREE_CODE(expr) == PARM_DECL
+       || TREE_CODE(expr) == RESULT_DECL)
+    TREE_ADDRESSABLE (expr) = 1;
+
   tree ret = build_fold_addr_expr_loc(location.gcc_location(), expr);
   return this->make_expression(ret);
 }


Or call mark_addressable, and update mark_addressable to avoid NULL 
pointer ICE:
The below patch also pass bootstrap-debug.

diff --git a/gcc/gimple-expr.c b/gcc/gimple-expr.c
index b8c732b632a..f682841391b 100644
--- a/gcc/gimple-expr.c
+++ b/gcc/gimple-expr.c
@@ -915,6 +915,7 @@ mark_addressable (tree x)
   if (TREE_CODE (x) == VAR_DECL
       && !DECL_EXTERNAL (x)
       && !TREE_STATIC (x)
+      && cfun != NULL
       && cfun->gimple_df != NULL
       && cfun->gimple_df->decls_to_pointers != NULL)
     {
diff --git a/gcc/go/go-gcc.cc b/gcc/go/go-gcc.cc
index 5d9dbb5d068..fe9dfaf8579 100644
--- a/gcc/go/go-gcc.cc
+++ b/gcc/go/go-gcc.cc
@@ -1680,6 +1680,7 @@ Gcc_backend::address_expression(Bexpression* 
bexpr, Location location)
   if (expr == error_mark_node)
     return this->error_expression();

+  mark_addressable(expr);
   tree ret = build_fold_addr_expr_loc(location.gcc_location(), expr);
   return this->make_expression(ret);
 }



I notice you mentioned "mark_addresssable" in PR.
And I had tried yesterday, it cause new ICEs at gimple-expr.c:918
below line:

  && cfun->gimple_df != NULL




Richard.

Jiufu Guo.

2021-05-14  Richard Biener  <rguent...@suse.de>
            Jiufu Guo <guoji...@linux.ibm.com>

            PR go/100537
            * go-gcc.cc
            (Gcc_backend::address_expression): Set TREE_ADDRESSABLE.

---
gcc/go/go-gcc.cc | 1 +
1 file changed, 1 insertion(+)

diff --git a/gcc/go/go-gcc.cc b/gcc/go/go-gcc.cc
index 5d9dbb5d068..8ed20a3b479 100644
--- a/gcc/go/go-gcc.cc
+++ b/gcc/go/go-gcc.cc
@@ -1680,6 +1680,7 @@ Gcc_backend::address_expression(Bexpression*
bexpr, Location location)
  if (expr == error_mark_node)
    return this->error_expression();

+  TREE_ADDRESSABLE (expr) = 1;
  tree ret = build_fold_addr_expr_loc(location.gcc_location(), expr);
  return this->make_expression(ret);
}