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Re: [PATCH, Pointer Bounds Checker 9/x] Cgraph extension


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2014-04-16 18:03 GMT+04:00 Ilya Enkovich <enkovich.gnu@gmail.com>:
> Hi,
>
> This patch introduces changes in call graph for Pointer Bounds Checker.
>
> New fields instrumented_version, instrumentation_clone and orig_decl are added for cgraph_node:
>  - instrumentation_clone field is 1 for nodes created for instrumented version of functions
>  - instrumented_version points to instrumented/original node
>  - orig_decl holds original function declaration for instrumented nodes in case original node is removed
>
> IPA_REF_CHKP reference type is introduced for nodes to reference instrumented function versions from originals.  It is used to have proper reachability analysis.
>
> When original function bodies are not needed anymore, functions are transformed into thunks having call edge to the instrumented function.  Therefore new field appeared in cgraph_thunk_info to mark such thunks.
>
> Does it look OK?
>
> Bootstrapped and tested on linux-x86_64.
>
> Thanks,
> Ilya
> --
> gcc/
>
> 2014-04-16  Ilya Enkovich  <ilya.enkovich@intel.com>
>
>         * cgraph.h (cgraph_thunk_info): Add add_pointer_bounds_args
>         field.
>         (cgraph_node): Add instrumented_version, orig_decl and
>         instrumentation_clone fields.
>         (symtab_alias_target): Allow IPA_REF_CHKP reference.
>         * cgraph.c (cgraph_remove_node): Fix instrumented_version
>         of the referenced node if any.
>         (dump_cgraph_node): Dump instrumentation_clone and
>         instrumented_version fields.
>         (verify_cgraph_node): Check correctness of IPA_REF_CHKP
>         references and instrumentation thunks.
>         * cgraphbuild.c (rebuild_cgraph_edges): Rebuild IPA_REF_CHKP
>         reference.
>         (cgraph_rebuild_references): Likewise.
>         * cgraphunit.c (assemble_thunks_and_aliases): Skip thunks
>         calling instrumneted function version.
>         * ipa-ref.h (ipa_ref_use): Add IPA_REF_CHKP.
>         (ipa_ref): increase size of use field.
>         * ipa-ref.c (ipa_ref_use_name): Add element for IPA_REF_CHKP.
>         * lto-cgraph.c (lto_output_node): Output instrumentation_clone,
>         thunk.add_pointer_bounds_args and orig_decl field.
>         (lto_output_ref): Adjust to new ipa_ref::use field size.
>         (input_overwrite_node): Read instrumentation_clone field.
>         (input_node): Read thunk.add_pointer_bounds_args and orig_decl
>         fields.
>         (input_ref): Adjust to new ipa_ref::use field size.
>         (input_cgraph_1): Compute instrumented_version fields and restore
>         IDENTIFIER_TRANSPARENT_ALIAS chains.
>         * lto-streamer.h (LTO_minor_version): Change minor version from
>         0 to 1.
>         * ipa.c (symtab_remove_unreachable_nodes): Consider instrumented
>         clone as address taken if the original one is address taken.
>         (cgraph_externally_visible_p): Mark instrumented 'main' as
>         externally visible.
>         (function_and_variable_visibility): Filter instrumentation
>         thunks.
>
>
> diff --git a/gcc/cgraph.c b/gcc/cgraph.c
> index be3661a..6210c68 100644
> --- a/gcc/cgraph.c
> +++ b/gcc/cgraph.c
> @@ -1828,6 +1828,12 @@ cgraph_remove_node (struct cgraph_node *node)
>      }
>    cgraph_n_nodes--;
>
> +  if (node->instrumented_version)
> +    {
> +      node->instrumented_version->instrumented_version = NULL;
> +      node->instrumented_version = NULL;
> +    }
> +
>    /* Clear out the node to NULL all pointers and add the node to the free
>       list.  */
>    memset (node, 0, sizeof (*node));
> @@ -2070,6 +2076,11 @@ dump_cgraph_node (FILE *f, struct cgraph_node *node)
>    if (indirect_calls_count)
>      fprintf (f, "  Has %i outgoing edges for indirect calls.\n",
>              indirect_calls_count);
> +
> +  if (node->instrumentation_clone)
> +    fprintf (f, "  Is instrumented version.\n");
> +  else if (node->instrumented_version)
> +    fprintf (f, "  Has instrumented version.\n");
>  }
>
>
> @@ -2850,7 +2861,9 @@ verify_cgraph_node (struct cgraph_node *node)
>         }
>        for (i = 0; ipa_ref_list_reference_iterate (&node->ref_list,
>                                                   i, ref); i++)
> -       if (ref->use != IPA_REF_ALIAS)
> +       if (ref->use == IPA_REF_CHKP)
> +         ;
> +       else if (ref->use != IPA_REF_ALIAS)
>           {
>             error ("Alias has non-alias reference");
>             error_found = true;
> @@ -2868,6 +2881,35 @@ verify_cgraph_node (struct cgraph_node *node)
>             error_found = true;
>           }
>      }
> +
> +  /* Check all nodes reference their instrumented versions.  */
> +  if (node->analyzed
> +      && node->instrumented_version
> +      && !node->instrumentation_clone)
> +    {
> +      bool ref_found = false;
> +      int i;
> +      struct ipa_ref *ref;
> +
> +      for (i = 0; ipa_ref_list_reference_iterate (&node->ref_list,
> +                                                 i, ref); i++)
> +       if (ref->use == IPA_REF_CHKP)
> +         {
> +           if (ref_found)
> +             {
> +               error ("Node has more than one chkp reference");
> +               error_found = true;
> +             }
> +           ref_found = true;
> +         }
> +
> +      if (!ref_found)
> +       {
> +         error ("Analyzed node has no reference to instrumented version");
> +         error_found = true;
> +       }
> +    }
> +
>    if (node->analyzed && node->thunk.thunk_p)
>      {
>        if (!node->callees)
> @@ -2885,6 +2927,12 @@ verify_cgraph_node (struct cgraph_node *node)
>           error ("Thunk is not supposed to have body");
>            error_found = true;
>          }
> +      if (node->thunk.add_pointer_bounds_args
> +         && node->callees->callee != node->instrumented_version)
> +       {
> +         error ("Instrumentation thunk has wrong edge callee");
> +          error_found = true;
> +       }
>      }
>    else if (node->analyzed && gimple_has_body_p (node->decl)
>             && !TREE_ASM_WRITTEN (node->decl)
> diff --git a/gcc/cgraph.h b/gcc/cgraph.h
> index a6a51cf..5e702a7 100644
> --- a/gcc/cgraph.h
> +++ b/gcc/cgraph.h
> @@ -191,6 +191,7 @@ struct GTY(()) cgraph_thunk_info {
>    tree alias;
>    bool this_adjusting;
>    bool virtual_offset_p;
> +  bool add_pointer_bounds_args;
>    /* Set to true when alias node is thunk.  */
>    bool thunk_p;
>  };
> @@ -373,6 +374,13 @@ public:
>    struct cgraph_node *prev_sibling_clone;
>    struct cgraph_node *clones;
>    struct cgraph_node *clone_of;
> +  /* If instrumentation_clone is 1 then instrumented_version points
> +     to the original function used to make instrumented version.
> +     Otherwise points to instrumented version of the function.  */
> +  struct cgraph_node *instrumented_version;
> +  /* If instrumentation_clone is 1 then orig_decl is the original
> +     function declaration.  */
> +  tree orig_decl;
>    /* For functions with many calls sites it holds map from call expression
>       to the edge to speed up cgraph_edge function.  */
>    htab_t GTY((param_is (struct cgraph_edge))) call_site_hash;
> @@ -433,6 +441,9 @@ public:
>    /* True if this decl calls a COMDAT-local function.  This is set up in
>       compute_inline_parameters and inline_call.  */
>    unsigned calls_comdat_local : 1;
> +  /* True when function is clone created for Pointer Bounds Checker
> +     instrumentation.  */
> +  unsigned instrumentation_clone : 1;
>  };
>
>
> @@ -1412,6 +1423,8 @@ symtab_alias_target (symtab_node *n)
>  {
>    struct ipa_ref *ref;
>    ipa_ref_list_reference_iterate (&n->ref_list, 0, ref);
> +  if (ref->use == IPA_REF_CHKP)
> +    ipa_ref_list_reference_iterate (&n->ref_list, 1, ref);
>    gcc_checking_assert (ref->use == IPA_REF_ALIAS);
>    return ref->referred;
>  }
> diff --git a/gcc/cgraphbuild.c b/gcc/cgraphbuild.c
> index 19961e2..a2b2106 100644
> --- a/gcc/cgraphbuild.c
> +++ b/gcc/cgraphbuild.c
> @@ -481,6 +481,10 @@ rebuild_cgraph_edges (void)
>    record_eh_tables (node, cfun);
>    gcc_assert (!node->global.inlined_to);
>
> +  if (node->instrumented_version
> +      && !node->instrumentation_clone)
> +    ipa_record_reference (node, node->instrumented_version, IPA_REF_CHKP, NULL);
> +
>    return 0;
>  }
>
> @@ -513,6 +517,11 @@ cgraph_rebuild_references (void)
>         ipa_record_stmt_references (node, gsi_stmt (gsi));
>      }
>    record_eh_tables (node, cfun);
> +
> +
> +  if (node->instrumented_version
> +      && !node->instrumentation_clone)
> +    ipa_record_reference (node, node->instrumented_version, IPA_REF_CHKP, NULL);
>  }
>
>  namespace {
> diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
> index 06283fc..ceb4060 100644
> --- a/gcc/cgraphunit.c
> +++ b/gcc/cgraphunit.c
> @@ -1702,7 +1702,8 @@ assemble_thunks_and_aliases (struct cgraph_node *node)
>    struct ipa_ref *ref;
>
>    for (e = node->callers; e;)
> -    if (e->caller->thunk.thunk_p)
> +    if (e->caller->thunk.thunk_p
> +       && !e->caller->thunk.add_pointer_bounds_args)
>        {
>         struct cgraph_node *thunk = e->caller;
>
> diff --git a/gcc/ipa-ref.c b/gcc/ipa-ref.c
> index 6aa41e6..3a055d9 100644
> --- a/gcc/ipa-ref.c
> +++ b/gcc/ipa-ref.c
> @@ -27,7 +27,7 @@ along with GCC; see the file COPYING3.  If not see
>  #include "cgraph.h"
>  #include "ipa-utils.h"
>
> -static const char *ipa_ref_use_name[] = {"read","write","addr","alias"};
> +static const char *ipa_ref_use_name[] = {"read","write","addr","alias","chkp"};
>
>  /* Return ipa reference from REFERING_NODE or REFERING_VARPOOL_NODE
>     to REFERED_NODE or REFERED_VARPOOL_NODE. USE_TYPE specify type
> diff --git a/gcc/ipa-ref.h b/gcc/ipa-ref.h
> index 4ce5f8d..d0df0bf 100644
> --- a/gcc/ipa-ref.h
> +++ b/gcc/ipa-ref.h
> @@ -29,7 +29,8 @@ enum GTY(()) ipa_ref_use
>    IPA_REF_LOAD,
>    IPA_REF_STORE,
>    IPA_REF_ADDR,
> -  IPA_REF_ALIAS
> +  IPA_REF_ALIAS,
> +  IPA_REF_CHKP
>  };
>
>  /* Record of reference in callgraph or varpool.  */
> @@ -40,7 +41,7 @@ struct GTY(()) ipa_ref
>    gimple stmt;
>    unsigned int lto_stmt_uid;
>    unsigned int referred_index;
> -  ENUM_BITFIELD (ipa_ref_use) use:2;
> +  ENUM_BITFIELD (ipa_ref_use) use:3;
>    unsigned int speculative:1;
>  };
>
> diff --git a/gcc/ipa.c b/gcc/ipa.c
> index 5ab3aed..1d7fa35 100644
> --- a/gcc/ipa.c
> +++ b/gcc/ipa.c
> @@ -508,6 +508,12 @@ symtab_remove_unreachable_nodes (bool before_inlining_p, FILE *file)
>               cgraph_node_remove_callees (node);
>               ipa_remove_all_references (&node->ref_list);
>               changed = true;
> +             if (node->thunk.thunk_p
> +                 && node->thunk.add_pointer_bounds_args)
> +               {
> +                 node->thunk.thunk_p = false;
> +                 node->thunk.add_pointer_bounds_args = false;
> +               }
>             }
>         }
>        else
> @@ -583,7 +589,10 @@ symtab_remove_unreachable_nodes (bool before_inlining_p, FILE *file)
>      if (node->address_taken
>         && !node->used_from_other_partition)
>        {
> -       if (!cgraph_for_node_and_aliases (node, has_addr_references_p, NULL, true))
> +       if (!cgraph_for_node_and_aliases (node, has_addr_references_p, NULL, true)
> +           && (!node->instrumentation_clone
> +               || !node->instrumented_version
> +               || !node->instrumented_version->address_taken))
>           {
>             if (file)
>               fprintf (file, " %s", node->name ());
> @@ -814,6 +823,10 @@ cgraph_externally_visible_p (struct cgraph_node *node,
>    if (MAIN_NAME_P (DECL_NAME (node->decl)))
>      return true;
>
> +  if (node->instrumentation_clone
> +      && MAIN_NAME_P (DECL_NAME (node->orig_decl)))
> +    return true;
> +
>    return false;
>  }
>
> @@ -1016,6 +1029,7 @@ function_and_variable_visibility (bool whole_program)
>         }
>
>        if (node->thunk.thunk_p
> +         && !node->thunk.add_pointer_bounds_args
>           && TREE_PUBLIC (node->decl))
>         {
>           struct cgraph_node *decl_node = node;
> diff --git a/gcc/lto-cgraph.c b/gcc/lto-cgraph.c
> index 999ce3d..58105f0 100644
> --- a/gcc/lto-cgraph.c
> +++ b/gcc/lto-cgraph.c
> @@ -526,6 +526,7 @@ lto_output_node (struct lto_simple_output_block *ob, struct cgraph_node *node,
>    bp_pack_value (&bp, node->thunk.thunk_p && !boundary_p, 1);
>    bp_pack_enum (&bp, ld_plugin_symbol_resolution,
>                 LDPR_NUM_KNOWN, node->resolution);
> +  bp_pack_value (&bp, node->instrumentation_clone, 1);
>    streamer_write_bitpack (&bp);
>
>    if (node->thunk.thunk_p && !boundary_p)
> @@ -533,11 +534,15 @@ lto_output_node (struct lto_simple_output_block *ob, struct cgraph_node *node,
>        streamer_write_uhwi_stream
>          (ob->main_stream,
>           1 + (node->thunk.this_adjusting != 0) * 2
> -         + (node->thunk.virtual_offset_p != 0) * 4);
> +         + (node->thunk.virtual_offset_p != 0) * 4
> +         + (node->thunk.add_pointer_bounds_args != 0) * 8);
>        streamer_write_uhwi_stream (ob->main_stream, node->thunk.fixed_offset);
>        streamer_write_uhwi_stream (ob->main_stream, node->thunk.virtual_value);
>      }
>    streamer_write_hwi_stream (ob->main_stream, node->profile_id);
> +
> +  if (node->instrumentation_clone)
> +    lto_output_fn_decl_index (ob->decl_state, ob->main_stream, node->orig_decl);
>  }
>
>  /* Output the varpool NODE to OB.
> @@ -613,7 +618,7 @@ lto_output_ref (struct lto_simple_output_block *ob, struct ipa_ref *ref,
>    struct cgraph_node *node;
>
>    bp = bitpack_create (ob->main_stream);
> -  bp_pack_value (&bp, ref->use, 2);
> +  bp_pack_value (&bp, ref->use, 3);
>    bp_pack_value (&bp, ref->speculative, 1);
>    streamer_write_bitpack (&bp);
>    nref = lto_symtab_encoder_lookup (encoder, ref->referred);
> @@ -1002,6 +1007,7 @@ input_overwrite_node (struct lto_file_decl_data *file_data,
>    node->thunk.thunk_p = bp_unpack_value (bp, 1);
>    node->resolution = bp_unpack_enum (bp, ld_plugin_symbol_resolution,
>                                      LDPR_NUM_KNOWN);
> +  node->instrumentation_clone = bp_unpack_value (bp, 1);
>    gcc_assert (flag_ltrans
>               || (!node->in_other_partition
>                   && !node->used_from_other_partition));
> @@ -1112,10 +1118,19 @@ input_node (struct lto_file_decl_data *file_data,
>        node->thunk.this_adjusting = (type & 2);
>        node->thunk.virtual_value = virtual_value;
>        node->thunk.virtual_offset_p = (type & 4);
> +      node->thunk.add_pointer_bounds_args = (type & 8);
>      }
>    if (node->alias && !node->analyzed && node->weakref)
>      node->alias_target = get_alias_symbol (node->decl);
>    node->profile_id = streamer_read_hwi (ib);
> +
> +  if (node->instrumentation_clone)
> +    {
> +      decl_index = streamer_read_uhwi (ib);
> +      fn_decl = lto_file_decl_data_get_fn_decl (file_data, decl_index);
> +      node->orig_decl = fn_decl;
> +    }
> +
>    return node;
>  }
>
> @@ -1196,7 +1211,7 @@ input_ref (struct lto_input_block *ib,
>    struct ipa_ref *ref;
>
>    bp = streamer_read_bitpack (ib);
> -  use = (enum ipa_ref_use) bp_unpack_value (&bp, 2);
> +  use = (enum ipa_ref_use) bp_unpack_value (&bp, 3);
>    speculative = (enum ipa_ref_use) bp_unpack_value (&bp, 1);
>    node = nodes[streamer_read_hwi (ib)];
>    ref = ipa_record_reference (referring_node, node, use, NULL);
> @@ -1337,6 +1352,22 @@ input_cgraph_1 (struct lto_file_decl_data *file_data,
>             cgraph (node)->global.inlined_to = cgraph (nodes[ref]);
>           else
>             cnode->global.inlined_to = NULL;
> +
> +         /* Compute instrumented_version.  */
> +         if (cnode->instrumentation_clone)
> +           {
> +             gcc_assert (cnode->orig_decl);
> +
> +             cnode->instrumented_version = cgraph_get_node (cnode->orig_decl);
> +             if (cnode->instrumented_version)
> +               cnode->instrumented_version->instrumented_version = cnode;
> +
> +             /* Restore decl names reference.  */
> +             if (IDENTIFIER_TRANSPARENT_ALIAS (DECL_ASSEMBLER_NAME (cnode->decl))
> +                 && !TREE_CHAIN (DECL_ASSEMBLER_NAME (cnode->decl)))
> +               TREE_CHAIN (DECL_ASSEMBLER_NAME (cnode->decl))
> +                 = DECL_ASSEMBLER_NAME (cnode->orig_decl);
> +           }
>         }
>
>        ref = (int) (intptr_t) node->same_comdat_group;
> diff --git a/gcc/lto-streamer.h b/gcc/lto-streamer.h
> index 51b1903..62a5fe0 100644
> --- a/gcc/lto-streamer.h
> +++ b/gcc/lto-streamer.h
> @@ -141,7 +141,7 @@ along with GCC; see the file COPYING3.  If not see
>  #define LTO_SECTION_NAME_PREFIX         ".gnu.lto_"
>
>  #define LTO_major_version 3
> -#define LTO_minor_version 0
> +#define LTO_minor_version 1
>
>  typedef unsigned char  lto_decl_flags_t;
>


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