http://sourceware.org/ml/binutils/2016-03/msg00119.html Subject: [patch] aout+coff: Fix strict-aliasing rules error --IJpNTDwzlM2Ie8A6 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi, https://bugzilla.redhat.com/show_bug.cgi?id=1315191 by Dan Horak gcc (GCC) 6.0.0 20160308 (experimental) gcc-6.0.0-0.15.fc24 gcc-6.0.0-0.15.fc25 It did compile with: gcc-6.0.0-0.14.fc24 aoutx.h:2504:7: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] int type_code = aout_symbol (symbol)->type & 0xff; ^~~ coffcode.h:1817:3: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] coffsymbol (section->symbol)->native = native; ^~~~~~~~~~ Full log attached. This fix is probably wrong as it drops the type safety. But ({ statements as expressions }) are probably not allowed in GDB. Jan --IJpNTDwzlM2Ie8A6 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename=1 bfd/ 2016-03-08 Jan Kratochvil Fix strict-aliasing rules compilation error. * libaout.h (aout_symbol): Remove type safe indirection. * libcoff-in.h (coffsymbol): Likewise. * libcoff.h: Regenerate. diff --git a/bfd/libaout.h b/bfd/libaout.h index 8b70a9f..b60c40c 100644 --- a/bfd/libaout.h +++ b/bfd/libaout.h @@ -448,9 +448,7 @@ struct aout_data_struct #define obj_aout_sym_hashes(bfd) (adata (bfd).sym_hashes) #define obj_aout_dynamic_info(bfd) (adata (bfd).dynamic_info) -/* We take the address of the first element of an asymbol to ensure that the - macro is only ever applied to an asymbol. */ -#define aout_symbol(asymbol) ((aout_symbol_type *)(&(asymbol)->the_bfd)) +#define aout_symbol(asymbol) ((aout_symbol_type *) (asymbol)) /* Information we keep for each a.out section. This is currently only used by the a.out backend linker. */ diff --git a/bfd/libcoff-in.h b/bfd/libcoff-in.h index 80f999d..fa1e9ac 100644 --- a/bfd/libcoff-in.h +++ b/bfd/libcoff-in.h @@ -188,9 +188,7 @@ struct xcoff_tdata #define xcoff_data(abfd) ((abfd)->tdata.xcoff_obj_data) -/* We take the address of the first element of an asymbol to ensure that the - macro is only ever applied to an asymbol. */ -#define coffsymbol(asymbol) ((coff_symbol_type *)(&((asymbol)->the_bfd))) +#define coffsymbol(asymbol) ((coff_symbol_type *) (asymbol)) /* Tdata for sections in XCOFF files. This is used by the linker. */ diff --git a/bfd/libcoff.h b/bfd/libcoff.h index bbed3e0..8ce525b 100644 --- a/bfd/libcoff.h +++ b/bfd/libcoff.h @@ -192,9 +192,7 @@ struct xcoff_tdata #define xcoff_data(abfd) ((abfd)->tdata.xcoff_obj_data) -/* We take the address of the first element of an asymbol to ensure that the - macro is only ever applied to an asymbol. */ -#define coffsymbol(asymbol) ((coff_symbol_type *)(&((asymbol)->the_bfd))) +#define coffsymbol(asymbol) ((coff_symbol_type *) (asymbol)) /* Tdata for sections in XCOFF files. This is used by the linker. */ --IJpNTDwzlM2Ie8A6 Content-Type: text/plain; charset=iso-2022-jp Content-Disposition: inline; filename=2 libtool: compile: gcc -DHAVE_CONFIG_H -I. -I. -I. -I./../include -DHAVE_x86_64_elf64_vec -DHAVE_i386_elf32_vec -DHAVE_iamcu_elf32_vec -DHAVE_x86_64_elf32_vec -DHAVE_i386_aout_linux_vec -DHAVE_i386_pei_vec -DHAVE_x86_64_pei_vec -DHAVE_l1om_elf64_vec -DHAVE_k1om_elf64_vec -DHAVE_elf64_le_vec -DHAVE_elf64_be_vec -DHAVE_elf32_le_vec -DHAVE_elf32_be_vec -DHAVE_plugin_vec -DBINDIR=\"/usr/local/bin\" -W -Wall -Wstrict-prototypes -Wmissing-prototypes -Wshadow -Werror -I./../zlib -g -O2 -MT aout32.lo -MD -MP -MF .deps/aout32.Tpo -c aout32.c -o aout32.o In file included from aout32.c:24:0: aoutx.h: In function ‘aout_32_write_syms’: aoutx.h:1871:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] H_PUT_16 (abfd, aout_symbol (g)->desc, nsp.e_desc); ^~~~~~~~ aoutx.h:1872:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] H_PUT_8 (abfd, aout_symbol (g)->other, nsp.e_other); ^~~~~~~ aoutx.h:1873:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] H_PUT_8 (abfd, aout_symbol (g)->type, nsp.e_type); ^~~~~~~ aoutx.h: In function ‘aout_32_get_symbol_info’: aoutx.h:2504:7: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] int type_code = aout_symbol (symbol)->type & 0xff; ^~~ aoutx.h:2515:7: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] ret->stab_other = (unsigned) (aout_symbol (symbol)->other & 0xff); ^~~ aoutx.h:2516:7: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] ret->stab_desc = (unsigned) (aout_symbol (symbol)->desc & 0xffff); ^~~ aoutx.h: In function ‘aout_32_print_symbol’: aoutx.h:2537:9: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] (unsigned) (aout_symbol (symbol)->desc & 0xffff), ^ aoutx.h:2538:9: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] (unsigned) (aout_symbol (symbol)->other & 0xff), ^ aoutx.h:2539:9: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] (unsigned) (aout_symbol (symbol)->type)); ^ aoutx.h:2549:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] (unsigned) (aout_symbol (symbol)->desc & 0xffff), ^ aoutx.h:2550:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] (unsigned) (aout_symbol (symbol)->other & 0xff), ^ aoutx.h:2551:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] (unsigned) (aout_symbol (symbol)->type & 0xff)); ^ cc1: all warnings being treated as errors libtool: compile: gcc -DHAVE_CONFIG_H -I. -I. -I. -I./../include -DHAVE_x86_64_elf64_vec -DHAVE_i386_elf32_vec -DHAVE_iamcu_elf32_vec -DHAVE_x86_64_elf32_vec -DHAVE_i386_aout_linux_vec -DHAVE_i386_pei_vec -DHAVE_x86_64_pei_vec -DHAVE_l1om_elf64_vec -DHAVE_k1om_elf64_vec -DHAVE_elf64_le_vec -DHAVE_elf64_be_vec -DHAVE_elf32_le_vec -DHAVE_elf32_be_vec -DHAVE_plugin_vec -DBINDIR=\"/usr/local/bin\" -W -Wall -Wstrict-prototypes -Wmissing-prototypes -Wshadow -Werror -I./../zlib -g -O2 -MT pei-i386.lo -MD -MP -MF .deps/pei-i386.Tpo -c pei-i386.c -o pei-i386.o In file included from coff-i386.c:614:0, from pei-i386.c:45: coffcode.h: In function ‘coff_new_section_hook’: coffcode.h:1817:3: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] coffsymbol (section->symbol)->native = native; ^~~~~~~~~~ cc1: all warnings being treated as errors libtool: compile: gcc -DHAVE_CONFIG_H -I. -I. -I. -I./../include -DHAVE_x86_64_elf64_vec -DHAVE_i386_elf32_vec -DHAVE_iamcu_elf32_vec -DHAVE_x86_64_elf32_vec -DHAVE_i386_aout_linux_vec -DHAVE_i386_pei_vec -DHAVE_x86_64_pei_vec -DHAVE_l1om_elf64_vec -DHAVE_k1om_elf64_vec -DHAVE_elf64_le_vec -DHAVE_elf64_be_vec -DHAVE_elf32_le_vec -DHAVE_elf32_be_vec -DHAVE_plugin_vec -DBINDIR=\"/usr/local/bin\" -W -Wall -Wstrict-prototypes -Wmissing-prototypes -Wshadow -Werror -I./../zlib -g -O2 -MT coffgen.lo -MD -MP -MF .deps/coffgen.Tpo -c coffgen.c -o coffgen.o coffgen.c: In function ‘coff_get_lineno’: coffgen.c:1510:3: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] return coffsymbol (symbol)->lineno; ^~~~~~ coffgen.c: In function ‘coff_get_symbol_info’: coffgen.c:2034:3: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] if (coffsymbol (symbol)->native != NULL ^~ coffgen.c:2035:7: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] && coffsymbol (symbol)->native->fix_value ^~ coffgen.c:2036:7: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] && coffsymbol (symbol)->native->is_sym) ^~ coffgen.c:2037:5: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] ret->value = coffsymbol (symbol)->native->u.syment.n_value - ^~~ coffgen.c: In function ‘coff_print_symbol’: coffgen.c:2059:9: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] coffsymbol (symbol)->native ? "n" : "g", ^~~~~~~~~~ coffgen.c:2060:9: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] coffsymbol (symbol)->lineno ? "l" : " "); ^~~~~~~~~~ coffgen.c:2064:7: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] if (coffsymbol (symbol)->native) ^~ coffgen.c:2068:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] combined_entry_type *combined = coffsymbol (symbol)->native; ^~~~~~~~~~~~~~~~~~~ coffgen.c:2070:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] struct lineno_cache_entry *l = coffsymbol (symbol)->lineno; ^~~~~~~~~~~~~~~~~~ coffgen.c:2191:6: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] coffsymbol (symbol)->native ? "n" : "g", ^~~~~~~~~~ coffgen.c:2192:6: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] coffsymbol (symbol)->lineno ? "l" : " ", ^~~~~~~~~~ cc1: all warnings being treated as errors libtool: compile: gcc -DHAVE_CONFIG_H -I. -I. -I. -I./../include -DHAVE_x86_64_elf64_vec -DHAVE_i386_elf32_vec -DHAVE_iamcu_elf32_vec -DHAVE_x86_64_elf32_vec -DHAVE_i386_aout_linux_vec -DHAVE_i386_pei_vec -DHAVE_x86_64_pei_vec -DHAVE_l1om_elf64_vec -DHAVE_k1om_elf64_vec -DHAVE_elf64_le_vec -DHAVE_elf64_be_vec -DHAVE_elf32_le_vec -DHAVE_elf32_be_vec -DHAVE_plugin_vec -DBINDIR=\"/usr/local/bin\" -W -Wall -Wstrict-prototypes -Wmissing-prototypes -Wshadow -Werror -I./../zlib -g -O2 -MT pei-x86_64.lo -MD -MP -MF .deps/pei-x86_64.Tpo -c pei-x86_64.c -o pei-x86_64.o In file included from coff-x86_64.c:741:0, from pei-x86_64.c:763: coffcode.h: In function ‘coff_new_section_hook’: coffcode.h:1817:3: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] coffsymbol (section->symbol)->native = native; ^~~~~~~~~~ cc1: all warnings being treated as errors --IJpNTDwzlM2Ie8A6--