| Message ID | CA+yXCZAhAJYTN1XbUxKmu8zg=SAjrLPhp2njffjPKWGhnH68jA@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
ping! On Mon, Sep 1, 2014 at 11:30 AM, Kito Cheng <kito.cheng@gmail.com> wrote: > Hi all: > > In arm-*-elf target some variable will missing size directive, > > for example: > > foo.c: > > void foo (void) { > static char bufbuf[8]; > } > > $ arm-none-eabi-gcc ./foo.c -S -o - > > ... > .align 2 > bufbuf.4078: > .space 8 > ... > .ident "GCC: (GNU) 5.0.0 20140828 (experimental)" > > > And then the size info will missing: > > $ arm-none-eabi-objdump ./foo.o -t > > ./foo.o: file format elf32-littlearm > > SYMBOL TABLE: > 00000000 l df *ABS* 00000000 zoo.c > 00000000 l d .text 00000000 .text > 00000000 l d .data 00000000 .data > 00000000 l d .bss 00000000 .bss > 00000000 l .bss 00000008 bufbuf.4078 > 00000000 l d .comment 00000000 .comment > 00000000 l d .ARM.attributes 00000000 .ARM.attributes > 00000000 g F .text 00000018 foo > > > ChangeLog > > 2014-09-01 Kito Cheng <kito@0xlab.org> > > * config/arm/unknown-elf.h (ASM_OUTPUT_ALIGNED_DECL_LOCAL): > Add size directive.
On Mon, Sep 1, 2014 at 4:30 AM, Kito Cheng <kito.cheng@gmail.com> wrote: > Hi all: > > In arm-*-elf target some variable will missing size directive, > > for example: > > foo.c: > > void foo (void) { > static char bufbuf[8]; > } > > $ arm-none-eabi-gcc ./foo.c -S -o - > > ... > .align 2 > bufbuf.4078: > .space 8 Thanks for this patch Kito. Nick / Richard : Any historical reasons as to why we use .space instead of the more common .comm / .lcomm directives to the assembler in the ARM backend ? If there are no reasons should we just move to using the standard COMMON_ASM_OP here rather than using .space ? Ofcourse needs to be tested to check if there are any missing corner cases. Ramana > ... > .ident "GCC: (GNU) 5.0.0 20140828 (experimental)" > > > And then the size info will missing: > > $ arm-none-eabi-objdump ./foo.o -t > > ./foo.o: file format elf32-littlearm > > SYMBOL TABLE: > 00000000 l df *ABS* 00000000 zoo.c > 00000000 l d .text 00000000 .text > 00000000 l d .data 00000000 .data > 00000000 l d .bss 00000000 .bss > 00000000 l .bss 00000008 bufbuf.4078 > 00000000 l d .comment 00000000 .comment > 00000000 l d .ARM.attributes 00000000 .ARM.attributes > 00000000 g F .text 00000018 foo > > > ChangeLog > > 2014-09-01 Kito Cheng <kito@0xlab.org> > > * config/arm/unknown-elf.h (ASM_OUTPUT_ALIGNED_DECL_LOCAL): > Add size directive.
On 09/09/14 14:32, Ramana Radhakrishnan wrote: > On Mon, Sep 1, 2014 at 4:30 AM, Kito Cheng <kito.cheng@gmail.com> wrote: >> Hi all: >> >> In arm-*-elf target some variable will missing size directive, >> >> for example: >> >> foo.c: >> >> void foo (void) { >> static char bufbuf[8]; >> } >> >> $ arm-none-eabi-gcc ./foo.c -S -o - >> >> ... >> .align 2 >> bufbuf.4078: >> .space 8 > > > Thanks for this patch Kito. > > Nick / Richard : Any historical reasons as to why we use .space > instead of the more common .comm / .lcomm directives to the assembler > in the ARM backend ? If there are no reasons should we just move to > using the standard COMMON_ASM_OP here rather than using .space ? > Ofcourse needs to be tested to check if there are any missing corner > cases. > .space puts space in the current section, I believe. .comm and .lcomm put the space in the common section; that's very different behaviour. R. > Ramana > > >> ... >> .ident "GCC: (GNU) 5.0.0 20140828 (experimental)" >> >> >> And then the size info will missing: >> >> $ arm-none-eabi-objdump ./foo.o -t >> >> ./foo.o: file format elf32-littlearm >> >> SYMBOL TABLE: >> 00000000 l df *ABS* 00000000 zoo.c >> 00000000 l d .text 00000000 .text >> 00000000 l d .data 00000000 .data >> 00000000 l d .bss 00000000 .bss >> 00000000 l .bss 00000008 bufbuf.4078 >> 00000000 l d .comment 00000000 .comment >> 00000000 l d .ARM.attributes 00000000 .ARM.attributes >> 00000000 g F .text 00000018 foo >> >> >> ChangeLog >> >> 2014-09-01 Kito Cheng <kito@0xlab.org> >> >> * config/arm/unknown-elf.h (ASM_OUTPUT_ALIGNED_DECL_LOCAL): >> Add size directive. >
Richard Earnshaw <rearnsha@arm.com> writes: > .space puts space in the current section, I believe. .comm and .lcomm > put the space in the common section; that's very different behaviour. The local common section is the .bss section. Andreas.
Kito Cheng <kito.cheng@gmail.com> writes: > .align 2 > bufbuf.4078: > .space 8 > ... > .ident "GCC: (GNU) 5.0.0 20140828 (experimental)" > > > And then the size info will missing: > > $ arm-none-eabi-objdump ./foo.o -t > > ./foo.o: file format elf32-littlearm > > SYMBOL TABLE: > 00000000 l df *ABS* 00000000 zoo.c > 00000000 l d .text 00000000 .text > 00000000 l d .data 00000000 .data > 00000000 l d .bss 00000000 .bss > 00000000 l .bss 00000008 bufbuf.4078 The size of bufbuf.4078 appears to be correct. Andreas.
On Tue, Sep 9, 2014 at 10:06 PM, Andreas Schwab <schwab@suse.de> wrote: > Kito Cheng <kito.cheng@gmail.com> writes: > >> .align 2 >> bufbuf.4078: >> .space 8 >> ... >> .ident "GCC: (GNU) 5.0.0 20140828 (experimental)" >> >> >> And then the size info will missing: >> >> $ arm-none-eabi-objdump ./foo.o -t >> >> ./foo.o: file format elf32-littlearm >> >> SYMBOL TABLE: >> 00000000 l df *ABS* 00000000 zoo.c >> 00000000 l d .text 00000000 .text >> 00000000 l d .data 00000000 .data >> 00000000 l d .bss 00000000 .bss >> 00000000 l .bss 00000008 bufbuf.4078 > > The size of bufbuf.4078 appears to be correct. Oops, my mistake, this will get correct size after this patch, it will get zero size without this patch :) $ cat foo.c: void foo (void) { static char bufbuf[8]; } $ arm-none-eabi-gcc ./foo.c -S -o - # before this patch ... .bss .align 2 bufbuf.4078: .space 8 .ident "GCC: (GNU) 5.0.0 20140908 (experimental)" # after this patch (add size directive ) ... .bss .align 2 bufbuf.4078: .space 8 .size bufbuf.4078, 8 .ident "GCC: (GNU) 5.0.0 20140909 (experimental)" Another solution is just don't define ASM_OUTPUT_ALIGNED_DECL_LOCAL and use default one, it will use .local + .comm (same as arm-linux-gnueabi) ... .size foo, .-foo .local bufbuf.4078 .comm bufbuf.4078,8,4 .ident "GCC: (GNU) 5.0.0 20140909 (experimental)" > Andreas.
From e0034653a4d457708fc4d858ea20fab70a42d798 Mon Sep 17 00:00:00 2001 From: Kito Cheng <kito.cheng@gmail.com> Date: Mon, 1 Sep 2014 11:19:13 +0800 Subject: [PATCH] Add missing size directive for arm-elf ChangeLog 2014-09-01 Kito Cheng <kito@0xlab.org> * config/arm/unknown-elf.h (ASM_OUTPUT_ALIGNED_DECL_LOCAL): Add size directive. --- gcc/config/arm/unknown-elf.h | 1 + 1 file changed, 1 insertion(+) diff --git a/gcc/config/arm/unknown-elf.h b/gcc/config/arm/unknown-elf.h index 56aa166..b4d1757 100644 --- a/gcc/config/arm/unknown-elf.h +++ b/gcc/config/arm/unknown-elf.h @@ -81,6 +81,7 @@ ASM_OUTPUT_ALIGN (FILE, floor_log2 (ALIGN / BITS_PER_UNIT)); \ ASM_OUTPUT_LABEL (FILE, NAME); \ fprintf (FILE, "\t.space\t%d\n", SIZE ? (int)(SIZE) : 1); \ + ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, SIZE); \ } \ while (0) -- 1.9.3
Hi all: In arm-*-elf target some variable will missing size directive, for example: foo.c: void foo (void) { static char bufbuf[8]; } $ arm-none-eabi-gcc ./foo.c -S -o - ... .align 2 bufbuf.4078: .space 8 ... .ident "GCC: (GNU) 5.0.0 20140828 (experimental)" And then the size info will missing: $ arm-none-eabi-objdump ./foo.o -t ./foo.o: file format elf32-littlearm SYMBOL TABLE: 00000000 l df *ABS* 00000000 zoo.c 00000000 l d .text 00000000 .text 00000000 l d .data 00000000 .data 00000000 l d .bss 00000000 .bss 00000000 l .bss 00000008 bufbuf.4078 00000000 l d .comment 00000000 .comment 00000000 l d .ARM.attributes 00000000 .ARM.attributes 00000000 g F .text 00000018 foo ChangeLog 2014-09-01 Kito Cheng <kito@0xlab.org> * config/arm/unknown-elf.h (ASM_OUTPUT_ALIGNED_DECL_LOCAL): Add size directive.