From patchwork Fri May 19 10:35:23 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Biener X-Patchwork-Id: 764574 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3wTkws5zDYz9s4s for ; Fri, 19 May 2017 20:35:57 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=gcc.gnu.org header.i=@gcc.gnu.org header.b="qV18za4u"; dkim-atps=neutral DomainKey-Signature: a=rsa-sha1; c=nofws; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:date :from:to:cc:subject:message-id:mime-version:content-type; q=dns; s=default; b=W/E0tilV5uCcMu/01q09jGcn/lFg29NRiyLUlE5jggitNOpGFl Bs0JldlotSmCIhtqlrR6xPB277K9HVMutEWeEZHDSj02L+GFV9r4rSL6gl/cupDw gjD+5dul2Q9C8AZzw5WWoLJAuWAKaShp0OV/pMDS0tqgWXr5ffOBIB5aw= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:date :from:to:cc:subject:message-id:mime-version:content-type; s= default; bh=JlzgToiotBXhiFl2/tw/7o/iGm8=; b=qV18za4u0j+DPSOBx581 EnE4gwD98I1dGiWkJ0AXn/baYEmdgFMfOn5y3JGTYjlqP8cOpgDt3b+gOzH9ThiR r5htoHgspPu/LWt0VQkbaBO/ffyi5E9J15sdis8jjBDis3ovsFeb5QhrftD/7AY4 C6MvF4EPIQZwtPthIyFhn4g= Received: (qmail 52708 invoked by alias); 19 May 2017 10:35:30 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Delivered-To: mailing list gcc-patches@gcc.gnu.org Received: (qmail 52410 invoked by uid 89); 19 May 2017 10:35:29 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-16.1 required=5.0 tests=BAYES_00, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_ASCII_DIVIDERS, RP_MATCHES_RCVD, SPF_PASS autolearn=ham version=3.3.2 spammy=endless, sim X-HELO: mx1.suse.de Received: from mx2.suse.de (HELO mx1.suse.de) (195.135.220.15) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 19 May 2017 10:35:22 +0000 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 70E6CABBD; Fri, 19 May 2017 10:35:23 +0000 (UTC) Date: Fri, 19 May 2017 12:35:23 +0200 (CEST) From: Richard Biener To: gcc-patches@gcc.gnu.org cc: jason@redhat.com Subject: [PATCH][1/2] Early LTO debug, simple-object part Message-ID: User-Agent: Alpine 2.20 (LSU 67 2015-01-07) MIME-Version: 1.0 This is a repost (unchanged) of the simple-object ELF support for early LTO debug transfer from IL object to a separate debug-only object file. Bootstrapped and tested on x86_64-unknown-linux-gnu. Richard. 2017-05-19 Richard Biener include/ * simple-object.h (simple_object_copy_lto_debug_sections): New function. libiberty/ * simple-object-common.h (struct simple_object_functions): Add copy_lto_debug_sections hook. * simple-object.c: Include fcntl.h. (handle_lto_debug_sections): New helper function. (simple_object_copy_lto_debug_sections): New function copying early LTO debug sections to regular debug sections in a new file. (simple_object_start_write): Handle NULL segment_name. * simple-object-coff.c (simple_object_coff_functions): Adjust for not implemented copy_lto_debug_sections hook. * simple-object-mach-o.c (simple_object_mach_o_functions): Likewise. * simple-object-xcoff.c (simple_object_xcoff_functions): Likewise. * simple-object-elf.c (SHT_NULL, SHT_SYMTAB, SHT_RELA, SHT_REL, SHT_GROUP): Add various sectopn header types. (SHF_EXCLUDE): Add flag. (Elf32_External_Sym, Elf64_External_Sym): Add symbol struct. (ELF_ST_BIND, ELF_ST_TYPE, ELF_ST_INFO): Add accessors. (STT_OBJECT, STT_FUNC, STT_TLS, STT_GNU_IFUNC): Add Symbol types. (STV_DEFAULT): Add symbol visibility. (SHN_COMMON): Add special section index name. (struct simple_object_elf_write): New. (simple_object_elf_start_write): Adjust for new private data. (simple_object_elf_write_shdr): Pass in values for all fields we write. (simple_object_elf_write_to_file): Adjust. Copy from recorded section headers if requested. (simple_object_elf_release_write): Release private data. (simple_object_elf_copy_lto_debug_sections): Copy and rename sections as denoted by PFN and all their dependences, symbols and relocations to the empty destination file. (simple_object_elf_functions): Adjust for copy_lto_debug_sections hook. Index: early-lto-debug/include/simple-object.h =================================================================== --- early-lto-debug.orig/include/simple-object.h 2016-10-19 13:19:58.012326431 +0200 +++ early-lto-debug/include/simple-object.h 2016-10-20 10:51:49.861722998 +0200 @@ -197,6 +197,14 @@ simple_object_write_to_file (simple_obje extern void simple_object_release_write (simple_object_write *); +/* Copy LTO debug sections from SRC_OBJECT to DEST. + If an error occurs, return the errno value in ERR and an error string. */ + +extern const char * +simple_object_copy_lto_debug_sections (simple_object_read *src_object, + const char *dest, + int *err); + #ifdef __cplusplus } #endif Index: early-lto-debug/libiberty/simple-object-common.h =================================================================== --- early-lto-debug.orig/libiberty/simple-object-common.h 2016-10-19 13:19:58.012326431 +0200 +++ early-lto-debug/libiberty/simple-object-common.h 2016-10-20 10:51:49.865723045 +0200 @@ -141,6 +141,12 @@ struct simple_object_functions /* Release the private data for an simple_object_write. */ void (*release_write) (void *); + + /* Copy LTO debug sections. */ + const char *(*copy_lto_debug_sections) (simple_object_read *sobj, + simple_object_write *dobj, + int (*pfn) (const char **), + int *err); }; /* The known object file formats. */ Index: early-lto-debug/libiberty/simple-object-elf.c =================================================================== --- early-lto-debug.orig/libiberty/simple-object-elf.c 2016-10-19 13:19:58.012326431 +0200 +++ early-lto-debug/libiberty/simple-object-elf.c 2016-10-20 10:51:49.865723045 +0200 @@ -183,8 +183,55 @@ typedef struct { /* Values for sh_type field. */ +#define SHT_NULL 0 /* Section header table entry unused */ #define SHT_PROGBITS 1 /* Program data */ +#define SHT_SYMTAB 2 /* Link editing symbol table */ #define SHT_STRTAB 3 /* A string table */ +#define SHT_RELA 4 /* Relocation entries with addends */ +#define SHT_REL 9 /* Relocation entries, no addends */ +#define SHT_GROUP 17 /* Section contains a section group */ + +/* Values for sh_flags field. */ + +#define SHF_EXCLUDE 0x80000000 /* Link editor is to exclude this + section from executable and + shared library that it builds + when those objects are not to be + further relocated. */ +/* Symbol table entry. */ + +typedef struct +{ + unsigned char st_name[4]; /* Symbol name (string tbl index) */ + unsigned char st_value[4]; /* Symbol value */ + unsigned char st_size[4]; /* Symbol size */ + unsigned char st_info; /* Symbol type and binding */ + unsigned char st_other; /* Symbol visibility */ + unsigned char st_shndx[2]; /* Section index */ +} Elf32_External_Sym; + +typedef struct +{ + unsigned char st_name[4]; /* Symbol name (string tbl index) */ + unsigned char st_info; /* Symbol type and binding */ + unsigned char st_other; /* Symbol visibility */ + unsigned char st_shndx[2]; /* Section index */ + unsigned char st_value[8]; /* Symbol value */ + unsigned char st_size[8]; /* Symbol size */ +} Elf64_External_Sym; + +#define ELF_ST_BIND(val) (((unsigned char) (val)) >> 4) +#define ELF_ST_TYPE(val) ((val) & 0xf) +#define ELF_ST_INFO(bind, type) (((bind) << 4) + ((type) & 0xf)) + +#define STT_OBJECT 1 /* Symbol is a data object */ +#define STT_FUNC 2 /* Symbol is a code object */ +#define STT_TLS 6 /* Thread local data object */ +#define STT_GNU_IFUNC 10 /* Symbol is an indirect code object */ + +#define STV_DEFAULT 0 /* Visibility is specified by binding type */ + +#define SHN_COMMON 0xFFF2 /* Associated symbol is in common */ /* Functions to fetch and store different ELF types, depending on the endianness and size. */ @@ -348,6 +395,14 @@ struct simple_object_elf_attributes unsigned int flags; }; +/* Private data for an simple_object_write. */ + +struct simple_object_elf_write +{ + struct simple_object_elf_attributes attrs; + unsigned char *shdrs; +}; + /* See if we have an ELF file. */ static void * @@ -675,12 +730,13 @@ simple_object_elf_start_write (void *att { struct simple_object_elf_attributes *attrs = (struct simple_object_elf_attributes *) attributes_data; - struct simple_object_elf_attributes *ret; + struct simple_object_elf_write *ret; /* We're just going to record the attributes, but we need to make a copy because the user may delete them. */ - ret = XNEW (struct simple_object_elf_attributes); - *ret = *attrs; + ret = XNEW (struct simple_object_elf_write); + ret->attrs = *attrs; + ret->shdrs = NULL; return ret; } @@ -766,8 +822,11 @@ static int simple_object_elf_write_shdr (simple_object_write *sobj, int descriptor, off_t offset, unsigned int sh_name, unsigned int sh_type, unsigned int sh_flags, + off_t sh_addr, unsigned int sh_offset, unsigned int sh_size, - unsigned int sh_link, unsigned int sh_addralign, + unsigned int sh_link, unsigned int sh_info, + unsigned int sh_addralign, + unsigned int sh_entsize, const char **errmsg, int *err) { struct simple_object_elf_attributes *attrs = @@ -788,12 +847,13 @@ simple_object_elf_write_shdr (simple_obj ELF_SET_FIELD (fns, cl, Shdr, buf, sh_name, Elf_Word, sh_name); ELF_SET_FIELD (fns, cl, Shdr, buf, sh_type, Elf_Word, sh_type); ELF_SET_FIELD (fns, cl, Shdr, buf, sh_flags, Elf_Addr, sh_flags); + ELF_SET_FIELD (fns, cl, Shdr, buf, sh_addr, Elf_Addr, sh_addr); ELF_SET_FIELD (fns, cl, Shdr, buf, sh_offset, Elf_Addr, sh_offset); ELF_SET_FIELD (fns, cl, Shdr, buf, sh_size, Elf_Addr, sh_size); ELF_SET_FIELD (fns, cl, Shdr, buf, sh_link, Elf_Word, sh_link); - /* sh_info left as zero. */ + ELF_SET_FIELD (fns, cl, Shdr, buf, sh_info, Elf_Word, sh_info); ELF_SET_FIELD (fns, cl, Shdr, buf, sh_addralign, Elf_Addr, sh_addralign); - /* sh_entsize left as zero. */ + ELF_SET_FIELD (fns, cl, Shdr, buf, sh_entsize, Elf_Word, sh_entsize); return simple_object_internal_write (descriptor, offset, buf, shdr_size, errmsg, err); @@ -811,8 +871,9 @@ static const char * simple_object_elf_write_to_file (simple_object_write *sobj, int descriptor, int *err) { - struct simple_object_elf_attributes *attrs = - (struct simple_object_elf_attributes *) sobj->data; + struct simple_object_elf_write *eow = + (struct simple_object_elf_write *) sobj->data; + struct simple_object_elf_attributes *attrs = &eow->attrs; unsigned char cl; size_t ehdr_size; size_t shdr_size; @@ -825,6 +886,7 @@ simple_object_elf_write_to_file (simple_ unsigned int first_sh_link; size_t sh_name; unsigned char zero; + unsigned secnum; if (!simple_object_elf_write_ehdr (sobj, descriptor, &errmsg, err)) return errmsg; @@ -862,21 +924,54 @@ simple_object_elf_write_to_file (simple_ else first_sh_link = shnum - 1; if (!simple_object_elf_write_shdr (sobj, descriptor, shdr_offset, - 0, 0, 0, 0, first_sh_size, first_sh_link, - 0, &errmsg, err)) + 0, 0, 0, 0, 0, first_sh_size, first_sh_link, + 0, 0, 0, &errmsg, err)) return errmsg; shdr_offset += shdr_size; sh_name = 1; + secnum = 0; for (section = sobj->sections; section != NULL; section = section->next) { size_t mask; size_t new_sh_offset; size_t sh_size; struct simple_object_write_section_buffer *buffer; + unsigned int sh_type = SHT_PROGBITS; + unsigned int sh_flags = 0; + off_t sh_addr = 0; + unsigned int sh_link = 0; + unsigned int sh_info = 0; + unsigned int sh_addralign = 1U << section->align; + unsigned int sh_entsize = 0; + if (eow->shdrs) + { + sh_type = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, + eow->shdrs + secnum * shdr_size, + sh_type, Elf_Word); + sh_flags = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, + eow->shdrs + secnum * shdr_size, + sh_flags, Elf_Addr); + sh_addr = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, + eow->shdrs + secnum * shdr_size, + sh_addr, Elf_Addr); + sh_link = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, + eow->shdrs + secnum * shdr_size, + sh_link, Elf_Word); + sh_info = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, + eow->shdrs + secnum * shdr_size, + sh_info, Elf_Word); + sh_addralign = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, + eow->shdrs + secnum * shdr_size, + sh_addralign, Elf_Addr); + sh_entsize = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, + eow->shdrs + secnum * shdr_size, + sh_entsize, Elf_Word); + secnum++; + } - mask = (1U << section->align) - 1; + mask = sh_addralign - 1; new_sh_offset = sh_offset + mask; new_sh_offset &= ~ mask; while (new_sh_offset > sh_offset) @@ -906,8 +1001,10 @@ simple_object_elf_write_to_file (simple_ } if (!simple_object_elf_write_shdr (sobj, descriptor, shdr_offset, - sh_name, SHT_PROGBITS, 0, sh_offset, - sh_size, 0, 1U << section->align, + sh_name, sh_type, sh_flags, + sh_addr, sh_offset, + sh_size, sh_link, sh_info, + sh_addralign, sh_entsize, &errmsg, err)) return errmsg; @@ -917,9 +1014,9 @@ simple_object_elf_write_to_file (simple_ } if (!simple_object_elf_write_shdr (sobj, descriptor, shdr_offset, - sh_name, SHT_STRTAB, 0, sh_offset, - sh_name + strlen (".shstrtab") + 1, 0, - 1, &errmsg, err)) + sh_name, SHT_STRTAB, 0, 0, sh_offset, + sh_name + strlen (".shstrtab") + 1, 0, 0, + 1, 0, &errmsg, err)) return errmsg; /* .shstrtab has a leading zero byte. */ @@ -954,9 +1051,363 @@ simple_object_elf_write_to_file (simple_ static void simple_object_elf_release_write (void *data) { + struct simple_object_elf_write *eow = (struct simple_object_elf_write *) data; + if (eow->shdrs) + XDELETE (eow->shdrs); XDELETE (data); } +/* Copy all sections in an ELF file. */ + +static const char * +simple_object_elf_copy_lto_debug_sections (simple_object_read *sobj, + simple_object_write *dobj, + int (*pfn) (const char **), + int *err) +{ + struct simple_object_elf_read *eor = + (struct simple_object_elf_read *) sobj->data; + const struct elf_type_functions *type_functions = eor->type_functions; + struct simple_object_elf_write *eow = + (struct simple_object_elf_write *) dobj->data; + unsigned char ei_class = eor->ei_class; + size_t shdr_size; + unsigned int shnum; + unsigned char *shdrs; + const char *errmsg; + unsigned char *shstrhdr; + size_t name_size; + off_t shstroff; + unsigned char *names; + unsigned int i; + int *pfnret; + const char **pfnname; + + shdr_size = (ei_class == ELFCLASS32 + ? sizeof (Elf32_External_Shdr) + : sizeof (Elf64_External_Shdr)); + + /* Read the section headers. We skip section 0, which is not a + useful section. */ + + shnum = eor->shnum; + shdrs = XNEWVEC (unsigned char, shdr_size * (shnum - 1)); + + if (!simple_object_internal_read (sobj->descriptor, + sobj->offset + eor->shoff + shdr_size, + shdrs, + shdr_size * (shnum - 1), + &errmsg, err)) + { + XDELETEVEC (shdrs); + return errmsg; + } + + /* Read the section names. */ + + shstrhdr = shdrs + (eor->shstrndx - 1) * shdr_size; + name_size = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shstrhdr, sh_size, Elf_Addr); + shstroff = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shstrhdr, sh_offset, Elf_Addr); + names = XNEWVEC (unsigned char, name_size); + if (!simple_object_internal_read (sobj->descriptor, + sobj->offset + shstroff, + names, name_size, &errmsg, err)) + { + XDELETEVEC (names); + XDELETEVEC (shdrs); + return errmsg; + } + + eow->shdrs = XNEWVEC (unsigned char, shdr_size * (shnum - 1)); + pfnret = XNEWVEC (int, shnum); + pfnname = XNEWVEC (const char *, shnum); + + /* First perform the callbacks to know which sections to preserve and + what name to use for those. */ + for (i = 1; i < shnum; ++i) + { + unsigned char *shdr; + unsigned int sh_name; + const char *name; + int ret; + + shdr = shdrs + (i - 1) * shdr_size; + sh_name = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_name, Elf_Word); + if (sh_name >= name_size) + { + *err = 0; + XDELETEVEC (names); + XDELETEVEC (shdrs); + return "ELF section name out of range"; + } + + name = (const char *) names + sh_name; + + ret = (*pfn) (&name); + pfnret[i - 1] = ret == 1 ? 0 : -1; + pfnname[i - 1] = name; + } + + /* Mark sections as preserved that are required by to be preserved + sections. */ + for (i = 1; i < shnum; ++i) + { + unsigned char *shdr; + unsigned int sh_type, sh_info, sh_link; + off_t offset; + off_t length; + + shdr = shdrs + (i - 1) * shdr_size; + sh_type = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_type, Elf_Word); + sh_info = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_info, Elf_Word); + sh_link = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_link, Elf_Word); + if (sh_type == SHT_GROUP) + { + /* Mark groups containing copied sections. */ + unsigned entsize = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_entsize, Elf_Addr); + unsigned char *ent, *buf; + int keep = 0; + offset = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_offset, Elf_Addr); + length = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_size, Elf_Addr); + buf = XNEWVEC (unsigned char, length); + if (!simple_object_internal_read (sobj->descriptor, + sobj->offset + offset, buf, + (size_t) length, &errmsg, err)) + { + XDELETEVEC (buf); + XDELETEVEC (names); + XDELETEVEC (shdrs); + return errmsg; + } + for (ent = buf + entsize; ent < buf + length; ent += entsize) + { + unsigned sec = type_functions->fetch_Elf_Word (ent); + if (pfnret[sec - 1] == 0) + keep = 1; + } + if (keep) + { + pfnret[sh_link - 1] = 0; + pfnret[i - 1] = 0; + } + } + if (sh_type == SHT_RELA + || sh_type == SHT_REL) + { + /* Mark relocation sections and symtab of copied sections. */ + if (pfnret[sh_info - 1] == 0) + { + pfnret[sh_link - 1] = 0; + pfnret[i - 1] = 0; + } + } + if (sh_type == SHT_SYMTAB) + { + /* Mark strings sections of copied symtabs. */ + if (pfnret[i - 1] == 0) + pfnret[sh_link - 1] = 0; + } + } + + /* Then perform the actual copying. */ + for (i = 1; i < shnum; ++i) + { + unsigned char *shdr; + unsigned int sh_name, sh_type; + const char *name; + off_t offset; + off_t length; + int ret; + const char *errmsg; + simple_object_write_section *dest; + off_t flags; + unsigned char *buf; + + shdr = shdrs + (i - 1) * shdr_size; + sh_name = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_name, Elf_Word); + if (sh_name >= name_size) + { + *err = 0; + XDELETEVEC (names); + XDELETEVEC (shdrs); + return "ELF section name out of range"; + } + + name = (const char *) names + sh_name; + offset = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_offset, Elf_Addr); + length = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_size, Elf_Addr); + sh_type = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_type, Elf_Word); + + ret = pfnret[i - 1]; + name = ret == 0 ? pfnname[i - 1] : ""; + + dest = simple_object_write_create_section (dobj, name, 0, &errmsg, err); + if (dest == NULL) + { + XDELETEVEC (names); + XDELETEVEC (shdrs); + return errmsg; + } + + /* Record the SHDR of the source. */ + memcpy (eow->shdrs + (i - 1) * shdr_size, shdr, shdr_size); + shdr = eow->shdrs + (i - 1) * shdr_size; + + /* Copy the data. + ??? This is quite wasteful and ideally would be delayed until + write_to_file (). Thus it questions the interfacing + which eventually should contain destination creation plus + writing. */ + /* Keep empty sections for sections we should discard. This avoids + the need to rewrite section indices in symtab and relocation + sections. */ + if (ret == 0) + { + buf = XNEWVEC (unsigned char, length); + if (!simple_object_internal_read (sobj->descriptor, + sobj->offset + offset, buf, + (size_t) length, &errmsg, err)) + { + XDELETEVEC (buf); + XDELETEVEC (names); + XDELETEVEC (shdrs); + return errmsg; + } + + /* If we are processing .symtab purge __gnu_lto_v1 and + __gnu_lto_slim symbols from it. */ + if (sh_type == SHT_SYMTAB) + { + unsigned entsize = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_entsize, Elf_Addr); + unsigned strtab = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_link, Elf_Word); + unsigned char *strshdr = shdrs + (strtab - 1) * shdr_size; + off_t stroff = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + strshdr, sh_offset, Elf_Addr); + size_t strsz = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + strshdr, sh_size, Elf_Addr); + char *strings = XNEWVEC (char, strsz); + unsigned char *ent; + simple_object_internal_read (sobj->descriptor, + sobj->offset + stroff, + (unsigned char *)strings, + strsz, &errmsg, err); + for (ent = buf; ent < buf + length; ent += entsize) + { + unsigned st_shndx = ELF_FETCH_FIELD (type_functions, ei_class, + Sym, ent, + st_shndx, Elf_Half); + unsigned char *st_info; + unsigned char *st_other; + if (ei_class == ELFCLASS32) + { + st_info = &((Elf32_External_Sym *)ent)->st_info; + st_other = &((Elf32_External_Sym *)ent)->st_other; + } + else + { + st_info = &((Elf64_External_Sym *)ent)->st_info; + st_other = &((Elf64_External_Sym *)ent)->st_other; + } + /* Eliminate all COMMONs - this includes __gnu_lto_v1 + and __gnu_lto_slim which otherwise cause endless + LTO plugin invocation. */ + if (st_shndx == SHN_COMMON) + /* Setting st_name to "" seems to work to purge + COMMON symbols (in addition to setting their + size to zero). */ + ; + /* We also need to remove symbols refering to sections + we'll eventually remove as with fat LTO objects + we otherwise get duplicate symbols at final link + (with GNU ld, gold is fine and ignores symbols in + sections marked as EXCLUDE). ld/20513 */ + else if (st_shndx != 0 + && st_shndx < shnum + && pfnret[st_shndx - 1] == -1) + /* Messing with st_shndx doesn't seem to work very + well. Likewise changing the symbol type to + a section symbol or making it local. + So just keep with making it unnamed. + Also make all regular symbols STT_OBJECT and + have default visibility, otherwise GNU ld warns + about mismatches for the same `' named symbol. */ + { + if (ELF_ST_TYPE (*st_info) == STT_FUNC + || ELF_ST_TYPE (*st_info) == STT_TLS + || ELF_ST_TYPE (*st_info) == STT_GNU_IFUNC) + *st_info = ELF_ST_INFO (ELF_ST_BIND (*st_info), + STT_OBJECT); + *st_other = STV_DEFAULT; + } + else + continue; + + /* For all purged symbols make the symbol unnamed. */ + ELF_SET_FIELD (type_functions, ei_class, Sym, + ent, st_name, Elf_Word, 0); + + /* At least set st_value and st_size to zero to not go + out of bounds. */ + ELF_SET_FIELD (type_functions, ei_class, Sym, + ent, st_value, Elf_Addr, 0); + ELF_SET_FIELD (type_functions, ei_class, Sym, + ent, st_size, Elf_Word, 0); + } + XDELETEVEC (strings); + } + + errmsg = simple_object_write_add_data (dobj, dest, buf, length, 1, err); + XDELETEVEC (buf); + if (errmsg) + { + XDELETEVEC (names); + XDELETEVEC (shdrs); + return errmsg; + } + } + else + { + /* For deleted sections mark the section header table entry as + unused. That allows the link editor to remove it in a partial + link. */ + ELF_SET_FIELD (type_functions, ei_class, Shdr, + shdr, sh_type, Elf_Addr, SHT_NULL); + } + + flags = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, + shdr, sh_flags, Elf_Addr); + if (ret == 0) + flags &= ~SHF_EXCLUDE; + else if (ret == -1) + flags |= SHF_EXCLUDE; + ELF_SET_FIELD (type_functions, ei_class, Shdr, + shdr, sh_flags, Elf_Addr, flags); + } + + XDELETEVEC (names); + XDELETEVEC (shdrs); + XDELETEVEC (pfnret); + XDELETEVEC (pfnname); + + return NULL; +} + + /* The ELF functions. */ const struct simple_object_functions simple_object_elf_functions = @@ -969,5 +1420,6 @@ const struct simple_object_functions sim simple_object_elf_release_attributes, simple_object_elf_start_write, simple_object_elf_write_to_file, - simple_object_elf_release_write + simple_object_elf_release_write, + simple_object_elf_copy_lto_debug_sections }; Index: early-lto-debug/libiberty/simple-object.c =================================================================== --- early-lto-debug.orig/libiberty/simple-object.c 2016-10-19 13:19:58.012326431 +0200 +++ early-lto-debug/libiberty/simple-object.c 2016-10-20 13:58:11.722714041 +0200 @@ -22,6 +22,7 @@ Boston, MA 02110-1301, USA. */ #include "simple-object.h" #include +#include #ifdef HAVE_STDLIB_H #include @@ -249,6 +250,86 @@ simple_object_find_section (simple_objec return 1; } +/* Callback to identify and rename LTO debug sections by name. + Returns 1 if NAME is a LTO debug section, 0 if not. */ + +static int +handle_lto_debug_sections (const char **name) +{ + /* ??? So we can't use .gnu.lto_ prefixed sections as the assembler + complains about bogus section flags. Which means we need to arrange + for that to be fixed or .gnu.debuglto_ marked as SHF_EXCLUDE (to make + fat lto object tooling work for the fat part). */ + /* ??? For now this handles both .gnu.lto_ and .gnu.debuglto_ prefixed + sections. */ + /* Copy LTO debug sections and rename them to their non-LTO name. */ + if (strncmp (*name, ".gnu.debuglto_", sizeof (".gnu.debuglto_") - 1) == 0) + { + *name = *name + sizeof (".gnu.debuglto_") - 1; + return 1; + } + else if (strncmp (*name, ".gnu.lto_.debug_", sizeof (".gnu.lto_.debug_") -1) == 0) + { + *name = *name + sizeof (".gnu.lto_") - 1; + return 1; + } + return 0; +} + +/* Copy LTO debug sections. */ + +const char * +simple_object_copy_lto_debug_sections (simple_object_read *sobj, + const char *dest, int *err) +{ + const char *errmsg; + simple_object_write *dest_sobj; + simple_object_attributes *attrs; + int outfd; + + if (! sobj->functions->copy_lto_debug_sections) + { + *err = EINVAL; + return "simple_object_copy_lto_debug_sections not implemented"; + } + + attrs = simple_object_fetch_attributes (sobj, &errmsg, err); + if (! attrs) + return errmsg; + dest_sobj = simple_object_start_write (attrs, NULL, &errmsg, err); + simple_object_release_attributes (attrs); + if (! dest_sobj) + return errmsg; + + errmsg = sobj->functions->copy_lto_debug_sections (sobj, dest_sobj, + handle_lto_debug_sections, + err); + if (errmsg) + { + simple_object_release_write (dest_sobj); + return errmsg; + } + + outfd = creat (dest, 00777); + if (outfd == -1) + { + *err = errno; + simple_object_release_write (dest_sobj); + return "open failed"; + } + + errmsg = simple_object_write_to_file (dest_sobj, outfd, err); + close (outfd); + if (errmsg) + { + simple_object_release_write (dest_sobj); + return errmsg; + } + + simple_object_release_write (dest_sobj); + return NULL; +} + /* Fetch attributes. */ simple_object_attributes * @@ -315,7 +396,7 @@ simple_object_start_write (simple_object return NULL; ret = XNEW (simple_object_write); ret->functions = attrs->functions; - ret->segment_name = xstrdup (segment_name); + ret->segment_name = segment_name ? xstrdup (segment_name) : NULL; ret->sections = NULL; ret->last_section = NULL; ret->data = data; Index: early-lto-debug/libiberty/simple-object-coff.c =================================================================== --- early-lto-debug.orig/libiberty/simple-object-coff.c 2016-10-19 13:19:58.012326431 +0200 +++ early-lto-debug/libiberty/simple-object-coff.c 2016-10-20 10:51:49.881723228 +0200 @@ -800,5 +800,6 @@ const struct simple_object_functions sim simple_object_coff_release_attributes, simple_object_coff_start_write, simple_object_coff_write_to_file, - simple_object_coff_release_write + simple_object_coff_release_write, + NULL }; Index: early-lto-debug/libiberty/simple-object-mach-o.c =================================================================== --- early-lto-debug.orig/libiberty/simple-object-mach-o.c 2016-10-19 13:19:58.012326431 +0200 +++ early-lto-debug/libiberty/simple-object-mach-o.c 2016-10-20 10:51:49.881723228 +0200 @@ -1374,5 +1374,6 @@ const struct simple_object_functions sim simple_object_mach_o_release_attributes, simple_object_mach_o_start_write, simple_object_mach_o_write_to_file, - simple_object_mach_o_release_write + simple_object_mach_o_release_write, + NULL }; Index: early-lto-debug/libiberty/simple-object-xcoff.c =================================================================== --- early-lto-debug.orig/libiberty/simple-object-xcoff.c 2016-10-19 13:19:58.012326431 +0200 +++ early-lto-debug/libiberty/simple-object-xcoff.c 2016-10-20 10:51:49.881723228 +0200 @@ -894,5 +894,6 @@ const struct simple_object_functions sim simple_object_xcoff_release_attributes, simple_object_xcoff_start_write, simple_object_xcoff_write_to_file, - simple_object_xcoff_release_write + simple_object_xcoff_release_write, + NULL };