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Hello! On 2009-12-15 13:55, Joseph S. Myers wrote: > On Tue, 15 Dec 2009, Thomas Schwinge wrote: >> On 2009-12-15 02:05, Joseph S. Myers wrote: >> > I'm not sure of the significance of having separate ARM/Thumb versions, >> >> Well, if I understand this correctly, it was you, together with Paul >> Brook, who have added this code on 2009-02-05. > > You need to look more carefully at the history before I merged Thumb-2 > support from EGLIBC to FSF ports. The new mcount entry point dates back > at least to <http://www.eglibc.org/archives/patches/msg00449.html> and > other discussions around that time, while Thumb-2 mcount comes from > <http://www.eglibc.org/archives/patches/msg00143.html>. I.e., on > 2009-02-05 I merged existing code without knowing the significance of > every bit of it. Thanks for the clarification. I had simply been looking at ChangeLog.arm which contains this: 2009-02-05 Paul Brook <paul@codesourcery.com> Joseph Myers <joseph@codesourcery.com> [...] * sysdeps/arm/machine-gmon.h (MCOUNT): Add Thumb-2 implementation. [...] ..., so I supposed that you had been directly involved with that. > You'll need to send the patch in a form appropriate for committing, tested > as both ARM and Thumb-2. Thusly done with the following patch. I folded the two _mcount definitions into one -- but that one now consists of nearly an equal amount of CPP conditionals compared to assembly instructions, so if you'd rather have a bit of assembly source code duplication, but better readability (?), then please tell and I'll modify accordingly. 2009-12-15 Thomas Schwinge <thomas@codesourcery.com> * sysdeps/arm/eabi/Makefile [gmon] (sysdep_routines): Add arm-mcount. * sysdeps/arm/eabi/machine-gmon.h (mcount_internal): Define to `__mcount_internal'. (MCOUNT (__gnu_mcount_nc), OLD_MCOUNT (_mcount), mcount): Move to... * sysdeps/arm/eabi/arm-mcount.S: ... this new file as __gnu_mcount_nc, _mcount, and mcount, respectively. diff --git a/glibc-ports-mainline/sysdeps/arm/eabi/Makefile b/glibc-ports-mainline/sysdeps/arm/eabi/Makefile index 36ddb8e..73185cb 100644 --- a/glibc-ports-mainline/sysdeps/arm/eabi/Makefile +++ b/glibc-ports-mainline/sysdeps/arm/eabi/Makefile @@ -15,6 +15,10 @@ static-only-routines += $(aeabi_constants) gen-as-const-headers += rtld-global-offsets.sym endif +ifeq ($(subdir),gmon) +sysdep_routines += arm-mcount +endif + ifeq ($(subdir),debug) CFLAGS-backtrace.c += -funwind-tables CFLAGS-tst-backtrace2.c += -funwind-tables diff --git a/glibc-ports-mainline/sysdeps/arm/eabi/arm-mcount.S b/glibc-ports-mainline/sysdeps/arm/eabi/arm-mcount.S new file mode 100644 index 0000000..2aa50b7 --- /dev/null +++ b/glibc-ports-mainline/sysdeps/arm/eabi/arm-mcount.S @@ -0,0 +1,83 @@ +/* Implementation of profiling support. ARM EABI version. + Copyright (C) 2008, 2009 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +/* Don't call mcount when calling mcount... */ +#undef PROF + +#include <sysdep.h> + + +#ifdef __thumb2__ + .thumb + .syntax unified +#endif + + +/* Use an assembly stub with a special ABI. The calling lr has been + pushed to the stack (which will be misaligned). We should preserve + all registers except ip and pop a word off the stack. + + NOTE: This assumes mcount_internal does not clobber any non-core + (coprocessor) registers. Currently this is true, but may require + additional attention in the future. + + The calling sequence looks something like: +func: + push {lr} + bl __gnu_mount_nc + <function body> +*/ + +ENTRY(__gnu_mcount_nc) + push {r0, r1, r2, r3, lr} + bic r1, lr, #1 + ldr r0, [sp, #20] + bl __mcount_internal + pop {r0, r1, r2, r3, ip, lr} + bx ip +END(__gnu_mcount_nc) + + +/* Provide old mcount for backwards compatibility. This requires + code be compiled with APCS frame pointers. */ + +ENTRY(_mcount) + stmdb sp!, {r0, r1, r2, r3, fp, lr} +#ifdef __thumb2__ + movs r0, fp + ittt ne + ldrne r0, [r0, #-4] +#else + movs fp, fp + ldrne r0, [fp, #-4] +#endif + movnes r1, lr + blne __mcount_internal +#ifdef __thumb2__ + ldmia sp!, {r0, r1, r2, r3, fp, pc} +#else + ldmia sp!, {r0, r1, r2, r3, fp, lr} + bx lr +#endif +END(_mcount) + +/* The canonical name for the function is `_mcount' in both C and asm, + but some old asm code might assume it's `mcount'. */ +#undef mcount +weak_alias (_mcount, mcount) diff --git a/glibc-ports-mainline/sysdeps/arm/eabi/machine-gmon.h b/glibc-ports-mainline/sysdeps/arm/eabi/machine-gmon.h index 189a9a3..aca23c9 100644 --- a/glibc-ports-mainline/sysdeps/arm/eabi/machine-gmon.h +++ b/glibc-ports-mainline/sysdeps/arm/eabi/machine-gmon.h @@ -1,5 +1,5 @@ /* Machine-dependent definitions for profiling support. ARM EABI version. - Copyright (C) 2008 Free Software Foundation, Inc. + Copyright (C) 2008, 2009 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -17,83 +17,18 @@ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ +#include <sysdep.h> + /* GCC for the ARM cannot compile __builtin_return_address(N) for N != 0, so we must use an assembly stub. */ -#include <sysdep.h> -static void mcount_internal (u_long frompc, u_long selfpc) __attribute_used__; +/* We must not pollute the global namespace. */ +#define mcount_internal __mcount_internal +extern void mcount_internal (u_long frompc, u_long selfpc) internal_function; #define _MCOUNT_DECL(frompc, selfpc) \ -static void mcount_internal (u_long frompc, u_long selfpc) - -/* Use an assembly stub with a special ABI. The calling lr has been - pushed to the stack (which will be misaligned). We should preserve - all registers except ip and pop a word off the stack. - - NOTE: This assumes mcount_internal does not clobber any non-core - (coprocessor) registers. Currently this is true, but may require - additional attention in the future. - - The calling sequence looks something like: -func: - push {lr} - bl __gnu_mount_nc - <function body> - */ - - -#define MCOUNT \ -void __attribute__((__naked__)) __gnu_mcount_nc(void) \ -{ \ - asm ("push {r0, r1, r2, r3, lr}\n\t" \ - "bic r1, lr, #1\n\t" \ - "ldr r0, [sp, #20]\n\t" \ - "bl mcount_internal\n\t" \ - "pop {r0, r1, r2, r3, ip, lr}\n\t" \ - "bx ip"); \ -} \ -OLD_MCOUNT - -/* Provide old mcount for backwards compatibility. This requires - code be compiled with APCS frame pointers. */ - -#ifndef NO_UNDERSCORES -/* The asm symbols for C functions are `_function'. - The canonical name for the counter function is `mcount', no _. */ -void _mcount (void) asm ("mcount"); -#else -/* The canonical name for the function is `_mcount' in both C and asm, - but some old asm code might assume it's `mcount'. */ -void _mcount (void); -weak_alias (_mcount, mcount) -#endif - -#ifdef __thumb2__ - -#define OLD_MCOUNT \ -void __attribute__((__naked__)) _mcount (void) \ -{ \ - __asm__("push {r0, r1, r2, r3, fp, lr};" \ - "movs r0, fp;" \ - "ittt ne;" \ - "ldrne r0, [r0, #-4];" \ - "movsne r1, lr;" \ - "blne mcount_internal;" \ - "pop {r0, r1, r2, r3, fp, pc}"); \ -} - -#else + void internal_function mcount_internal (u_long frompc, u_long selfpc) -#define OLD_MCOUNT \ -void __attribute__((__naked__)) _mcount (void) \ -{ \ - __asm__("stmdb sp!, {r0, r1, r2, r3, fp, lr};" \ - "movs fp, fp;" \ - "ldrne r0, [fp, #-4];" \ - "movnes r1, lr;" \ - "blne mcount_internal;" \ - "ldmia sp!, {r0, r1, r2, r3, fp, lr};" \ - "bx lr"); \ -} -#endif +/* Define MCOUNT as empty since we have the implementation in another file. */ +#define MCOUNT Regards, Thomas
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