On Tue, Nov 09, 2021 at 10:44:45AM +0100, Jakub Jelinek via Gcc-patches wrote:
> On Tue, Nov 09, 2021 at 08:12:05AM +0100, Richard Biener wrote:
> > > So, here is 1), 2), 3) implemented. With this patch alone,
> > > g++.dg/pch/system-2.C test ICEs. This is because GCC 12 has added
> > > function::x_range_query member, which is set to &global_ranges on
> > > cfun creation and is:
> > > range_query * GTY ((skip)) x_range_query;
> > > which means when a PIE binary writes PCH and a PIE binary loaded
> > > at a different address loads it, cfun->x_range_query might be a garbage
> > > pointer. We can either apply a patch like the attached one after
> > > this inline patch, but then probably callback is misnamed and we should
> > > rename it to relocate_and_skip or something similar. Or we could
> > > e.g. during gimplification overwrite cfun->x_range_query = &global_ranges.
> >
> > I think struct function allocation should initialize it to NULL and
> > the init to &global_ranges be done only when we do init_tree_ssa?
> > In fact x_range_query could be moved to the gimple_df substructure
> > to make that clear.
>
> Agreed, Andrew/Aldy, what do you think?
>
> > Hopefully PCH happens before init_tree_ssa.
>
> I think it does.
Unfortunately, seems cfun->x_range_query is used already in the FEs :(.
I was trying:
--- gcc/function.h.jj 2021-08-31 22:55:23.072795814 +0200
+++ gcc/function.h 2021-11-09 11:33:22.656779018 +0100
@@ -312,8 +312,9 @@ struct GTY(()) function {
/* Range query mechanism for functions. The default is to pick up
global ranges. If a pass wants on-demand ranges OTOH, it must
- call enable/disable_ranger(). The pointer is never null. It
- should be queried by calling get_range_query(). */
+ call enable/disable_ranger(). The pointer is never null in between
+ init_tree_ssa and delete_tree_ssa. It should be queried by calling
+ get_range_query(). */
range_query * GTY ((skip)) x_range_query;
/* Last statement uid. */
--- gcc/function.c.jj 2021-07-20 22:31:11.088835781 +0200
+++ gcc/function.c 2021-11-09 11:33:47.695424319 +0100
@@ -4873,8 +4873,6 @@ allocate_struct_function (tree fndecl, b
binding annotations among them. */
cfun->debug_nonbind_markers = lang_hooks.emits_begin_stmt
&& MAY_HAVE_DEBUG_MARKER_STMTS;
-
- cfun->x_range_query = &global_ranges;
}
/* This is like allocate_struct_function, but pushes a new cfun for FNDECL
--- gcc/tree-ssa.c.jj 2021-11-03 23:02:44.367985554 +0100
+++ gcc/tree-ssa.c 2021-11-09 12:02:07.095351378 +0100
@@ -44,6 +44,7 @@ along with GCC; see the file COPYING3.
#include "stringpool.h"
#include "attribs.h"
#include "asan.h"
+#include "value-query.h"
/* Pointer map of variable mappings, keyed by edge. */
static hash_map<edge, auto_vec<edge_var_map> > *edge_var_maps;
@@ -1224,6 +1225,7 @@ init_tree_ssa (struct function *fn, int
{
fn->gimple_df = ggc_cleared_alloc<gimple_df> ();
fn->gimple_df->default_defs = hash_table<ssa_name_hasher>::create_ggc (20);
+ fn->x_range_query = &global_ranges;
pt_solution_reset (&fn->gimple_df->escaped);
init_ssanames (fn, size);
}
@@ -1246,6 +1248,7 @@ delete_tree_ssa (struct function *fn)
delete fn->gimple_df->decls_to_pointers;
fn->gimple_df->decls_to_pointers = NULL;
fn->gimple_df = NULL;
+ fn->x_range_query = NULL;
/* We no longer need the edge variable maps. */
redirect_edge_var_map_empty ();
but that ICEs with:
#0 0x0000555556d27348 in get_range (val=val@entry=0x7fffe9f8c2d0,
stmt=0x7fffffffbb80, stmt@entry=0x0, minmax=minmax@entry=0x7fffffffbc10,
rvals=0x0)
at ../../gcc/tree-ssa-strlen.c:217
#1 0x0000555556a2fe73 in get_offset_range (x=0x7fffe9f8c2d0, stmt=0x0,
r=0x7fffffffbd70, rvals=<optimized out>) at ../../gcc/pointer-query.cc:92
#2 0x0000555556a33d3e in handle_array_ref (aref=0x7fffe7e17620,
addr=<optimized out>, ostype=1, pref=0x7fffffffc000, snlim=..., qry=<optimized
out>, stmt=<optimized out>)
at ../../gcc/pointer-query.cc:1621
#3 0x0000555556a3669d in compute_objsize (ptr=0x7fffe81b3100, stmt=<optimized
out>, ostype=1, pref=0x7fffffffc000, ptr_qry=0x7fffffffbf00) at
../../gcc/pointer-query.cc:2154
#4 0x0000555556a368e4 in compute_objsize (ptr=ptr@entry=0x7fffe81b3100,
stmt=stmt@entry=0x0, ostype=ostype@entry=1, pref=pref@entry=0x7fffffffc000,
rvals=rvals@entry=0x0)
at ../../gcc/pointer-query.cc:2172
#5 0x0000555556383f09 in compute_objsize (pref=0x7fffffffc000, ostype=1,
ptr=0x7fffe81b3100) at ../../gcc/pointer-query.h:262
#6 warn_placement_new_too_small (type=0x7fffe9f8a3f0, nelts=0x7fffe81b3160,
size=0x7fffe9f8c108, oper=0x7fffe81b3100) at ../../gcc/cp/init.c:2621
#7 0x000055555638cf9e in build_new_1 (placement=<optimized out>,
type=0x7fffe9f8a3f0, nelts=<optimized out>, init=0x7fffffffc3d0,
globally_qualified_p=<optimized out>, complain=3)
at ../../gcc/cp/init.c:3287
#8 0x000055555638dd92 in build_new (loc=<optimized out>,
placement=placement@entry=0x7fffffffc3c8, type=<optimized out>,
type@entry=0x7fffe9f8a3f0, nelts=0x7fffe81b3160,
nelts@entry=0x7fffe81b3120, init=init@entry=0x7fffffffc3d0,
use_global_new=use_global_new@entry=0, complain=3) at ../../gcc/cp/init.c:3838
Apparently the range_of_expr can handle some tree cases through
range_query::get_tree_range, like INTEGER_CSTs, ADDR_EXPRs,
and some binary and unary ops.
Jakub
