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[192.55.55.37]) by mx.google.com with ESMTPSA id gs7sm16307216wib.10.2015.04.14.02.16.37 (version=TLSv1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 14 Apr 2015 02:16:40 -0700 (PDT) Date: Tue, 14 Apr 2015 09:16:00 -0000 From: Ilya Enkovich To: Jan Hubicka Cc: gcc-patches Subject: Re: [CHKP, PATCH] Fix LTO cgraph merge for instrumented functions Message-ID: <20150414091414.GA50171@msticlxl57.ims.intel.com> References: <20150312102706.GL27860@msticlxl57.ims.intel.com> <20150319083455.GD64546@msticlxl57.ims.intel.com> <20150402170115.GB21276@atrey.karlin.mff.cuni.cz> <20150403184915.GS21276@atrey.karlin.mff.cuni.cz> <20150410011532.GA17443@kam.mff.cuni.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150410011532.GA17443@kam.mff.cuni.cz> User-Agent: Mutt/1.5.21 (2010-09-15) X-IsSubscribed: yes X-SW-Source: 2015-04/txt/msg00649.txt.bz2 On 10 Apr 03:15, Jan Hubicka wrote: > > > > References are not streamed out for nodes which are referenced in a > > partition but don't belong to it ('continue' condition in output_refs > > loop). > > Yeah, but it already special cases aliases (because we now always preserve IPA_REF_ALIAS link > in the boundary, so I think making IPA_REF_CHKP to be rpeserved should go the same path) > so we can special case the instrumentation thunks too? Any cgraph_node having instrumented clone should have it, not only instrumentation thunks. Surely we can make an exception for IPA_REF_CHKP. > > > > > > > > I suppose we still need to > > > 1) write_symbol and lto-symtab should know that transparent aliases are not real > > > symbols and ignore them. We have predicate symtab_node::real_symbol_p, > > > I suppose it should return true. > > > > > > I think cgraph_merge and varpool_merge in lto-symtab needs to know what to do > > > when merging two symbols with transparent aliases. > > > 2) At some point we need to populate transparent alias links as discussed in the > > > other thread. > > > 3) For safety, I guess we want symbol_table::change_decl_assembler_name to either > > > sanity check there are no trasparent alias links pointing to old assembler > > > names or update it. > > > > Wouldn't search for possible referring via transparent aliases nodes > > be too expensive? > > Changing of decl_assembler_name is not very common and if we set up the links > only after renaming of statics, i think we are safe. But it would be better to > keep verify it at some point. > > I suppose verify_node check that there is no transparent alias link on symbols > were it is not supposed to be and that there is link when it is supposed to be (i.e. > symtab_state is >=EXPANSION and symbol is either weakref on tragets w/o native weakrefs > or instrumentation cone. > > Would you please mind adding the test and making sure it triggers when things are > out of sync? > OK, but I suppose it should be a part of transparent alias links rework discussed in another thread. BTW are you going to intoroduce transparent aliases in cgraph soon? > > > > > 4) I think we want verify_node to check that transparent alias links and chkp points > > > as intended and only on those symbols where they need to be > > > > > > There is also logic in lto-partition to always insert alias target > > >> > OK, so you have the chkp references that links to instrumented_version. > > >> > You do not stream them for boundary symbols but for some reason they are needed, > > >> > but when you can end up with wrong CHKP link? > > >> > > >> Wrong links may appear when cgraph nodes are merged. > > > > > > I see, I think you really want to fix these at merging time as sugested in 1). > > > In this case even the node->instrumented_version pointer may be out of date and > > > point to a node that lost in merging? > > > > node->instrumented_version is redirected and never points to lost > > symbol. But during merge we may have situations when > > (node->instrumented_version->instrumented_version != node) because of > > multiple not merged (yet) symbols referencing the same merged target. > > OK, which should not be a problem if we stream the links instead of rebuilding them, right? IPA_REF_CHKP refs don't affect instrumented_version merging. And I actually don't see here any problems, instrumented_version links always come into consistent state when symbol merging finishes. Here is a new patch version. It has no chkp_maybe_fix_chkp_ref function, IPA_REF_CHKP references are streamed out instead. Bootstrapped and tested on x86_64-unknown-linux-gnu. OK for trunk? I also want to port it to GCC 5 branch after release. Thanks, Ilya -- gcc/ 2015-04-14 Ilya Enkovich * ipa.c (symbol_table::remove_unreachable_nodes): Don't remove instumentation thunks calling reachable functions. * lto-cgraph.c (output_refs): Always output IPA_REF_CHKP. * lto/lto-partition.c (privatize_symbol_name_1): New. (privatize_symbol_name): Privatize both decl and orig_decl names for instrumented functions. gcc/testsuite/ 2015-04-14 Ilya Enkovich * gcc.dg/lto/chkp-privatize-1_0.c: New. * gcc.dg/lto/chkp-privatize-1_1.c: New. * gcc.dg/lto/chkp-privatize-2_0.c: New. * gcc.dg/lto/chkp-privatize-2_1.c: New. diff --git a/gcc/ipa.c b/gcc/ipa.c index b3752de..3054afe 100644 --- a/gcc/ipa.c +++ b/gcc/ipa.c @@ -492,7 +492,22 @@ symbol_table::remove_unreachable_nodes (FILE *file) } else if (cnode->thunk.thunk_p) enqueue_node (cnode->callees->callee, &first, &reachable); - + + /* For instrumentation clones we always need original + function node for proper LTO privatization. */ + if (cnode->instrumentation_clone + && reachable.contains (cnode) + && cnode->definition) + { + gcc_assert (cnode->instrumented_version || in_lto_p); + if (cnode->instrumented_version) + { + enqueue_node (cnode->instrumented_version, &first, + &reachable); + reachable.add (cnode->instrumented_version); + } + } + /* If any reachable function has simd clones, mark them as reachable as well. */ if (cnode->simd_clones) diff --git a/gcc/lto-cgraph.c b/gcc/lto-cgraph.c index ac50e4b..ea352f1 100644 --- a/gcc/lto-cgraph.c +++ b/gcc/lto-cgraph.c @@ -805,8 +805,33 @@ output_refs (lto_symtab_encoder_t encoder) { symtab_node *node = lto_symtab_encoder_deref (encoder, i); + /* IPA_REF_ALIAS and IPA_REF_CHKP references are always preserved + in the boundary. Alias node can't have other references and + can be always handled as if it's not in the boundary. */ if (!node->alias && !lto_symtab_encoder_in_partition_p (encoder, node)) - continue; + { + cgraph_node *cnode = dyn_cast (node); + /* Output IPA_REF_CHKP reference. */ + if (cnode + && cnode->instrumented_version + && !cnode->instrumentation_clone) + { + for (int i = 0; node->iterate_reference (i, ref); i++) + if (ref->use == IPA_REF_CHKP) + { + if (lto_symtab_encoder_lookup (encoder, ref->referred) + != LCC_NOT_FOUND) + { + int nref = lto_symtab_encoder_lookup (encoder, node); + streamer_write_gcov_count_stream (ob->main_stream, 1); + streamer_write_uhwi_stream (ob->main_stream, nref); + lto_output_ref (ob, ref, encoder); + } + break; + } + } + continue; + } count = node->ref_list.nreferences (); if (count) diff --git a/gcc/lto/lto-partition.c b/gcc/lto/lto-partition.c index 235b735..7d117e9 100644 --- a/gcc/lto/lto-partition.c +++ b/gcc/lto/lto-partition.c @@ -877,27 +877,13 @@ validize_symbol_for_target (symtab_node *node) } } -/* Mangle NODE symbol name into a local name. - This is necessary to do - 1) if two or more static vars of same assembler name - are merged into single ltrans unit. - 2) if previously static var was promoted hidden to avoid possible conflict - with symbols defined out of the LTO world. */ +/* Helper for privatize_symbol_name. Mangle NODE symbol name + represented by DECL. */ static bool -privatize_symbol_name (symtab_node *node) +privatize_symbol_name_1 (symtab_node *node, tree decl) { - tree decl = node->decl; - const char *name; - cgraph_node *cnode = dyn_cast (node); - - /* If we want to privatize instrumentation clone - then we need to change original function name - which is used via transparent alias chain. */ - if (cnode && cnode->instrumentation_clone) - decl = cnode->orig_decl; - - name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)); + const char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)); if (must_not_rename (node, name)) return false; @@ -906,31 +892,57 @@ privatize_symbol_name (symtab_node *node) symtab->change_decl_assembler_name (decl, clone_function_name_1 (name, "lto_priv")); + if (node->lto_file_data) lto_record_renamed_decl (node->lto_file_data, name, IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl))); + + if (symtab->dump_file) + fprintf (symtab->dump_file, + "Privatizing symbol name: %s -> %s\n", + name, IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl))); + + return true; +} + +/* Mangle NODE symbol name into a local name. + This is necessary to do + 1) if two or more static vars of same assembler name + are merged into single ltrans unit. + 2) if previously static var was promoted hidden to avoid possible conflict + with symbols defined out of the LTO world. */ + +static bool +privatize_symbol_name (symtab_node *node) +{ + if (!privatize_symbol_name_1 (node, node->decl)) + return false; + /* We could change name which is a target of transparent alias chain of instrumented function name. Fix alias chain if so .*/ - if (cnode) + if (cgraph_node *cnode = dyn_cast (node)) { tree iname = NULL_TREE; if (cnode->instrumentation_clone) - iname = DECL_ASSEMBLER_NAME (cnode->decl); + { + /* If we want to privatize instrumentation clone + then we also need to privatize original function. */ + if (cnode->instrumented_version) + privatize_symbol_name (cnode->instrumented_version); + else + privatize_symbol_name_1 (cnode, cnode->orig_decl); + iname = DECL_ASSEMBLER_NAME (cnode->decl); + TREE_CHAIN (iname) = DECL_ASSEMBLER_NAME (cnode->orig_decl); + } else if (cnode->instrumented_version - && cnode->instrumented_version->orig_decl == decl) - iname = DECL_ASSEMBLER_NAME (cnode->instrumented_version->decl); - - if (iname) + && cnode->instrumented_version->orig_decl == cnode->decl) { - gcc_assert (IDENTIFIER_TRANSPARENT_ALIAS (iname)); - TREE_CHAIN (iname) = DECL_ASSEMBLER_NAME (decl); + iname = DECL_ASSEMBLER_NAME (cnode->instrumented_version->decl); + TREE_CHAIN (iname) = DECL_ASSEMBLER_NAME (cnode->decl); } } - if (symtab->dump_file) - fprintf (symtab->dump_file, - "Privatizing symbol name: %s -> %s\n", - name, IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl))); + return true; } diff --git a/gcc/testsuite/gcc.dg/lto/chkp-privatize-1_0.c b/gcc/testsuite/gcc.dg/lto/chkp-privatize-1_0.c new file mode 100644 index 0000000..2054aa15 --- /dev/null +++ b/gcc/testsuite/gcc.dg/lto/chkp-privatize-1_0.c @@ -0,0 +1,17 @@ +/* { dg-lto-do link } */ +/* { dg-require-effective-target mpx } */ +/* { dg-lto-options { { -Ofast -flto -fcheck-pointer-bounds -mmpx } } } */ + +extern int __attribute__((noinline)) f1 (int i); + +static int __attribute__((noinline)) +f2 (int i) +{ + return i + 6; +} + +int +main (int argc, char **argv) +{ + return f1 (argc) + f2 (argc); +} diff --git a/gcc/testsuite/gcc.dg/lto/chkp-privatize-1_1.c b/gcc/testsuite/gcc.dg/lto/chkp-privatize-1_1.c new file mode 100644 index 0000000..4fa8656 --- /dev/null +++ b/gcc/testsuite/gcc.dg/lto/chkp-privatize-1_1.c @@ -0,0 +1,11 @@ +static int __attribute__((noinline)) +f2 (int i) +{ + return 2 * i; +} + +int __attribute__((noinline)) +f1 (int i) +{ + return f2 (i) + 10; +} diff --git a/gcc/testsuite/gcc.dg/lto/chkp-privatize-2_0.c b/gcc/testsuite/gcc.dg/lto/chkp-privatize-2_0.c new file mode 100644 index 0000000..be7f601 --- /dev/null +++ b/gcc/testsuite/gcc.dg/lto/chkp-privatize-2_0.c @@ -0,0 +1,18 @@ +/* { dg-lto-do link } */ +/* { dg-require-effective-target mpx } */ +/* { dg-lto-options { { -Ofast -flto -fcheck-pointer-bounds -mmpx } } } */ + +static int +__attribute__ ((noinline)) +func1 (int i) +{ + return i + 2; +} + +extern int func2 (int i); + +int +main (int argc, char **argv) +{ + return func1 (argc) + func2 (argc) + 1; +} diff --git a/gcc/testsuite/gcc.dg/lto/chkp-privatize-2_1.c b/gcc/testsuite/gcc.dg/lto/chkp-privatize-2_1.c new file mode 100644 index 0000000..db39e7f --- /dev/null +++ b/gcc/testsuite/gcc.dg/lto/chkp-privatize-2_1.c @@ -0,0 +1,8 @@ +int func1 = 10; + +int +func2 (int i) +{ + func1++; + return i + func1; +}