From 5fcffe51f0feba3b795e6668582c63760db8389a Mon Sep 17 00:00:00 2001 From: Markus Trippelsdorf Date: Fri, 17 Oct 2014 05:10:07 +0000 Subject: [PATCH] Fix pr61848, linux kernel miscompile This patch cures the linux kernel boot failure when compiled using trunk gcc. At its heart, the problem is caused by merge_decls merging from the old decl to the new decl, then copying back to the old decl and discarding the new. When Jan moved some fields to the symtab, "copying back to the old decl" was lost for those fields. Really, it would be best if merge_decls was rewritten to merge everything to the kept decl, but here I'm just doing that for fields accessed via decl_with_vis.symtab_node. 2014-10-17 Alan Modra gcc/c/ PR middle-end/61848 * c-decl.c (merge_decls): Don't merge section name or tls model to newdecl symtab node, instead merge to olddecl. Override existing olddecl section name. Set tls_model for all thread-local vars, not just OMP thread-private ones. Remove incorrect comment. gcc/cp/ PR middle-end/61848 * decl.c (merge_decls): Don't merge section name, comdat group or tls model to newdecl symtab node, instead merge to olddecl. Override existing olddecl section name. Set tls_model for all thread-local vars, not just OMP thread-private ones. Remove incorrect comment. 2014-10-17 Markus Trippelsdorf PR middle-end/61848 * g++.dg/torture/pr61848.C: New testcase. * gcc.c-torture/compile/pr61848.c: New testcase. From-SVN: r216361 --- gcc/ChangeLog | 8 +++ gcc/c/c-decl.c | 28 +++++---- gcc/cp/ChangeLog | 9 +++ gcc/cp/decl.c | 63 +++++++++++-------- gcc/testsuite/ChangeLog | 6 ++ gcc/testsuite/g++.dg/torture/pr61848.C | 5 ++ gcc/testsuite/gcc.c-torture/compile/pr61848.c | 5 ++ 7 files changed, 84 insertions(+), 40 deletions(-) create mode 100644 gcc/testsuite/g++.dg/torture/pr61848.C create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr61848.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 8f76145135a..b55d5d44117 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2014-10-17 Alan Modra + + PR middle-end/61848 + * c-decl.c (merge_decls): Don't merge section name or tls model + to newdecl symtab node, instead merge to olddecl. Override + existing olddecl section name. Set tls_model for all thread-local + vars, not just OMP thread-private ones. Remove incorrect comment. + 2014-10-16 DJ Delorie * flag-types.h (sanitize_code): Don't assume targets have 32-bit diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c index fb16be6769c..839c67bf7e9 100644 --- a/gcc/c/c-decl.c +++ b/gcc/c/c-decl.c @@ -2297,22 +2297,10 @@ merge_decls (tree newdecl, tree olddecl, tree newtype, tree oldtype) /* Merge the threadprivate attribute. */ if (TREE_CODE (olddecl) == VAR_DECL && C_DECL_THREADPRIVATE_P (olddecl)) - { - set_decl_tls_model (newdecl, DECL_TLS_MODEL (olddecl)); - C_DECL_THREADPRIVATE_P (newdecl) = 1; - } + C_DECL_THREADPRIVATE_P (newdecl) = 1; if (CODE_CONTAINS_STRUCT (TREE_CODE (olddecl), TS_DECL_WITH_VIS)) { - /* Merge the section attribute. - We want to issue an error if the sections conflict but that - must be done later in decl_attributes since we are called - before attributes are assigned. */ - if ((DECL_EXTERNAL (olddecl) || TREE_PUBLIC (olddecl) || TREE_STATIC (olddecl)) - && DECL_SECTION_NAME (newdecl) == NULL - && DECL_SECTION_NAME (olddecl)) - set_decl_section_name (newdecl, DECL_SECTION_NAME (olddecl)); - /* Copy the assembler name. Currently, it can only be defined in the prototype. */ COPY_DECL_ASSEMBLER_NAME (olddecl, newdecl); @@ -2522,6 +2510,20 @@ merge_decls (tree newdecl, tree olddecl, tree newtype, tree oldtype) (char *) newdecl + sizeof (struct tree_decl_common), tree_code_size (TREE_CODE (olddecl)) - sizeof (struct tree_decl_common)); olddecl->decl_with_vis.symtab_node = snode; + + if ((DECL_EXTERNAL (olddecl) + || TREE_PUBLIC (olddecl) + || TREE_STATIC (olddecl)) + && DECL_SECTION_NAME (newdecl) != NULL) + set_decl_section_name (olddecl, DECL_SECTION_NAME (newdecl)); + + /* This isn't quite correct for something like + int __thread x attribute ((tls_model ("local-exec"))); + extern int __thread x; + as we'll lose the "local-exec" model. */ + if (TREE_CODE (olddecl) == VAR_DECL + && DECL_THREAD_LOCAL_P (newdecl)) + set_decl_tls_model (olddecl, DECL_TLS_MODEL (newdecl)); break; } diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 016c8f6f6f1..1148e9566ad 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,12 @@ +2014-10-17 Alan Modra + + PR middle-end/61848 + * decl.c (merge_decls): Don't merge section name, comdat group or + tls model to newdecl symtab node, instead merge to olddecl. + Override existing olddecl section name. Set tls_model for all + thread-local vars, not just OMP thread-private ones. Remove + incorrect comment. + 2014-10-16 Andrew MacLeod * cp-tree.h: Adjust include files. diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index 3eba4dcd1d6..1b214ab4090 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -1967,7 +1967,6 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend) if (!DECL_LANG_SPECIFIC (newdecl)) retrofit_lang_decl (newdecl); - set_decl_tls_model (newdecl, DECL_TLS_MODEL (olddecl)); CP_DECL_THREADPRIVATE_P (newdecl) = 1; } } @@ -2030,15 +2029,6 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend) } } - /* Merge the section attribute. - We want to issue an error if the sections conflict but that must be - done later in decl_attributes since we are called before attributes - are assigned. */ - if ((DECL_EXTERNAL (olddecl) || TREE_PUBLIC (olddecl) || TREE_STATIC (olddecl)) - && DECL_SECTION_NAME (newdecl) == NULL - && DECL_SECTION_NAME (olddecl) != NULL) - set_decl_section_name (newdecl, DECL_SECTION_NAME (olddecl)); - if (TREE_CODE (newdecl) == FUNCTION_DECL) { DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (newdecl) @@ -2083,19 +2073,6 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend) /* Merge the storage class information. */ merge_weak (newdecl, olddecl); - if ((TREE_CODE (olddecl) == FUNCTION_DECL || TREE_CODE (olddecl) == VAR_DECL) - && (DECL_EXTERNAL (olddecl) || TREE_PUBLIC (olddecl) || TREE_STATIC (olddecl)) - && DECL_ONE_ONLY (olddecl)) - { - struct symtab_node *symbol; - if (TREE_CODE (olddecl) == FUNCTION_DECL) - symbol = cgraph_node::get_create (newdecl); - else - symbol = varpool_node::get_create (newdecl); - symbol->set_comdat_group (symtab_node::get - (olddecl)->get_comdat_group ()); - } - DECL_DEFER_OUTPUT (newdecl) |= DECL_DEFER_OUTPUT (olddecl); TREE_PUBLIC (newdecl) = TREE_PUBLIC (olddecl); TREE_STATIC (olddecl) = TREE_STATIC (newdecl) |= TREE_STATIC (olddecl); @@ -2449,12 +2426,12 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend) } else { - size_t size = tree_code_size (TREE_CODE (olddecl)); + size_t size = tree_code_size (TREE_CODE (newdecl)); memcpy ((char *) olddecl + sizeof (struct tree_common), (char *) newdecl + sizeof (struct tree_common), sizeof (struct tree_decl_common) - sizeof (struct tree_common)); - switch (TREE_CODE (olddecl)) + switch (TREE_CODE (newdecl)) { case LABEL_DECL: case VAR_DECL: @@ -2466,14 +2443,14 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend) { struct symtab_node *snode = NULL; - if (TREE_CODE (olddecl) == VAR_DECL + if (TREE_CODE (newdecl) == VAR_DECL && (TREE_STATIC (olddecl) || TREE_PUBLIC (olddecl) || DECL_EXTERNAL (olddecl))) snode = symtab_node::get (olddecl); memcpy ((char *) olddecl + sizeof (struct tree_decl_common), (char *) newdecl + sizeof (struct tree_decl_common), size - sizeof (struct tree_decl_common) + TREE_CODE_LENGTH (TREE_CODE (newdecl)) * sizeof (char *)); - if (TREE_CODE (olddecl) == VAR_DECL) + if (TREE_CODE (newdecl) == VAR_DECL) olddecl->decl_with_vis.symtab_node = snode; } break; @@ -2485,6 +2462,38 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend) break; } } + + if (TREE_CODE (newdecl) == FUNCTION_DECL + || TREE_CODE (newdecl) == VAR_DECL) + { + if (DECL_EXTERNAL (olddecl) + || TREE_PUBLIC (olddecl) + || TREE_STATIC (olddecl)) + { + /* Merge the section attribute. + We want to issue an error if the sections conflict but that must be + done later in decl_attributes since we are called before attributes + are assigned. */ + if (DECL_SECTION_NAME (newdecl) != NULL) + set_decl_section_name (olddecl, DECL_SECTION_NAME (newdecl)); + + if (DECL_ONE_ONLY (newdecl)) + { + struct symtab_node *oldsym, *newsym; + if (TREE_CODE (olddecl) == FUNCTION_DECL) + oldsym = cgraph_node::get_create (olddecl); + else + oldsym = varpool_node::get_create (olddecl); + newsym = symtab_node::get (newdecl); + oldsym->set_comdat_group (newsym->get_comdat_group ()); + } + } + + if (TREE_CODE (newdecl) == VAR_DECL + && DECL_THREAD_LOCAL_P (newdecl)) + set_decl_tls_model (olddecl, DECL_TLS_MODEL (newdecl)); + } + DECL_UID (olddecl) = olddecl_uid; if (olddecl_friend) DECL_FRIEND_P (olddecl) = 1; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 7f159c65e7f..e24b295a826 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2014-10-17 Markus Trippelsdorf + + PR middle-end/61848 + * g++.dg/torture/pr61848.C: New testcase. + * gcc.c-torture/compile/pr61848.c: New testcase. + 2014-10-16 Oleg Endo * gcc.target/sh/cmpstr.c: Fix excess failures caused by switch to GNU11. diff --git a/gcc/testsuite/g++.dg/torture/pr61848.C b/gcc/testsuite/g++.dg/torture/pr61848.C new file mode 100644 index 00000000000..beb490c7543 --- /dev/null +++ b/gcc/testsuite/g++.dg/torture/pr61848.C @@ -0,0 +1,5 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target named_sections } */ +/* { dg-final { scan-assembler "mysection" } } */ +extern char foo; +char foo __attribute__ ((__section__(".mysection"))); diff --git a/gcc/testsuite/gcc.c-torture/compile/pr61848.c b/gcc/testsuite/gcc.c-torture/compile/pr61848.c new file mode 100644 index 00000000000..beb490c7543 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/compile/pr61848.c @@ -0,0 +1,5 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target named_sections } */ +/* { dg-final { scan-assembler "mysection" } } */ +extern char foo; +char foo __attribute__ ((__section__(".mysection"))); -- 2.30.2