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* [Bug target/53256] New: [avr] Attribute 'interrupt' shall override attribute 'signal'
@ 2012-05-06 11:41 gjl at gcc dot gnu.org
2012-05-06 12:27 ` [Bug target/53256] " gjl at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: gjl at gcc dot gnu.org @ 2012-05-06 11:41 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53256
Bug #: 53256
Summary: [avr] Attribute 'interrupt' shall override attribute
'signal'
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: target
AssignedTo: gjl@gcc.gnu.org
ReportedBy: gjl@gcc.gnu.org
CC: j@uriah.heep.sax.de
Target: avr
AVR-LibC offered attributes 'interrupt' and 'signal' as INTERRUPT and SIGNAL
through its API. This changed at some point in time to ISR which may lead to
code that adds attribute 'interrupt' and attribute 'signal' at the same time.
This leads to code that is not IRQ-safe in the current implementation which is:
1) Attributes 'interrupt' and 'signal' are exclusive. Specifying both at the
same time for the same function has not a well-defined behavior.
2) 'interrupt' emits a SEI instruction as the very first instruction of the
function.
3) Neither attributes make assumptions on the function's worker code. In
particular, they do *not* assume that interrupts are not (re-)enabled by the
user code. Thus, it is safe to enable IRQs at any place in the function body.
This "safe" covers only the generated code and IRQ-safeness of SP changes and
the instructions themselves, it does *not* cover the IRQ and timing layout of
the application.
4) The AVR hardware globally disables IRQs when an IRQ is raised. This allows
more efficient code in 'signal' prologues compared to 'interrupt' prologues in
cases where the stack pointer has to be written. Writing SP is not an atomic
operation on all devices, and special precautions must be taken if SP is
written and IRQs might be on.
As of this extension request 1) shall be changed to:
1') Attribute 'interrupt' shall override attribute 'signal'. No warning should
be issued in such a case. The documentation should be extended.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/53256] [avr] Attribute 'interrupt' shall override attribute 'signal'
2012-05-06 11:41 [Bug target/53256] New: [avr] Attribute 'interrupt' shall override attribute 'signal' gjl at gcc dot gnu.org
@ 2012-05-06 12:27 ` gjl at gcc dot gnu.org
2012-05-09 16:40 ` gjl at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: gjl at gcc dot gnu.org @ 2012-05-06 12:27 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53256
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P4
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2012-05-06
Target Milestone|--- |4.7.1
Ever Confirmed|0 |1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/53256] [avr] Attribute 'interrupt' shall override attribute 'signal'
2012-05-06 11:41 [Bug target/53256] New: [avr] Attribute 'interrupt' shall override attribute 'signal' gjl at gcc dot gnu.org
2012-05-06 12:27 ` [Bug target/53256] " gjl at gcc dot gnu.org
@ 2012-05-09 16:40 ` gjl at gcc dot gnu.org
2012-05-09 16:41 ` gjl at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: gjl at gcc dot gnu.org @ 2012-05-09 16:40 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53256
--- Comment #1 from Georg-Johann Lay <gjl at gcc dot gnu.org> 2012-05-09 16:29:06 UTC ---
Author: gjl
Date: Wed May 9 16:28:53 2012
New Revision: 187342
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=187342
Log:
PR target/53256
* config/avr/elf.h (ASM_DECLARE_FUNCTION_NAME): Remove.
* config/avr/avr-protos.h (avr_asm_declare_function_name): Remove.
* config/avr/avr.h (struct machine_function): Add attributes_checked_p.
* config/avr/avr.c (avr_asm_declare_function_name): Remove.
(expand_prologue): Move initialization of cfun->machine->is_naked,
is_interrupt, is_signal, is_OS_task, is_OS_main from here to...
(avr_set_current_function): ...this new static function.
(TARGET_SET_CURRENT_FUNCTION): New define.
(avr_function_ok_for_sibcall): Use cfun->machine->is_* instead of
checking attributes of current_function_decl.
(avr_regs_to_save): Ditto.
(signal_function_p): Rename to avr_signal_function_p.
(interrupt_function_p): Rename to avr_interrupt_function_p.
* doc/extend.texi (Function Attributes): Better explanation of
'interrupt' and 'signal' for AVR. Move 'ifunc' down to establish
alphabetical order.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/config/avr/avr-protos.h
trunk/gcc/config/avr/avr.c
trunk/gcc/config/avr/avr.h
trunk/gcc/config/avr/elf.h
trunk/gcc/doc/extend.texi
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/53256] [avr] Attribute 'interrupt' shall override attribute 'signal'
2012-05-06 11:41 [Bug target/53256] New: [avr] Attribute 'interrupt' shall override attribute 'signal' gjl at gcc dot gnu.org
2012-05-06 12:27 ` [Bug target/53256] " gjl at gcc dot gnu.org
2012-05-09 16:40 ` gjl at gcc dot gnu.org
@ 2012-05-09 16:41 ` gjl at gcc dot gnu.org
2012-05-09 17:11 ` gjl at gcc dot gnu.org
2012-06-08 22:42 ` gjl at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: gjl at gcc dot gnu.org @ 2012-05-09 16:41 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53256
--- Comment #2 from Georg-Johann Lay <gjl at gcc dot gnu.org> 2012-05-09 16:39:39 UTC ---
Author: gjl
Date: Wed May 9 16:39:33 2012
New Revision: 187343
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=187343
Log:
Backport from 2012-05-12 mainline r187342.
PR target/53256
* config/avr/elf.h (ASM_DECLARE_FUNCTION_NAME): Remove.
* config/avr/avr-protos.h (avr_asm_declare_function_name): Remove.
* config/avr/avr.h (struct machine_function): Add attributes_checked_p.
* config/avr/avr.c (avr_asm_declare_function_name): Remove.
(expand_prologue): Move initialization of cfun->machine->is_naked,
is_interrupt, is_signal, is_OS_task, is_OS_main from here to...
(avr_set_current_function): ...this new static function.
(TARGET_SET_CURRENT_FUNCTION): New define.
(avr_function_ok_for_sibcall): Use cfun->machine->is_* instead of
checking attributes of current_function_decl.
(avr_regs_to_save): Ditto.
(signal_function_p): Rename to avr_signal_function_p.
(interrupt_function_p): Rename to avr_interrupt_function_p.
* doc/extend.texi (Function Attributes): Better explanation of
'interrupt' and 'signal' for AVR. Move 'ifunc' down to establish
alphabetical order.
Modified:
branches/gcc-4_7-branch/gcc/ChangeLog
branches/gcc-4_7-branch/gcc/config/avr/avr-protos.h
branches/gcc-4_7-branch/gcc/config/avr/avr.c
branches/gcc-4_7-branch/gcc/config/avr/avr.h
branches/gcc-4_7-branch/gcc/config/avr/elf.h
branches/gcc-4_7-branch/gcc/doc/extend.texi
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/53256] [avr] Attribute 'interrupt' shall override attribute 'signal'
2012-05-06 11:41 [Bug target/53256] New: [avr] Attribute 'interrupt' shall override attribute 'signal' gjl at gcc dot gnu.org
` (2 preceding siblings ...)
2012-05-09 16:41 ` gjl at gcc dot gnu.org
@ 2012-05-09 17:11 ` gjl at gcc dot gnu.org
2012-06-08 22:42 ` gjl at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: gjl at gcc dot gnu.org @ 2012-05-09 17:11 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53256
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
--- Comment #3 from Georg-Johann Lay <gjl at gcc dot gnu.org> 2012-05-09 17:03:49 UTC ---
Added in 4.7.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/53256] [avr] Attribute 'interrupt' shall override attribute 'signal'
2012-05-06 11:41 [Bug target/53256] New: [avr] Attribute 'interrupt' shall override attribute 'signal' gjl at gcc dot gnu.org
` (3 preceding siblings ...)
2012-05-09 17:11 ` gjl at gcc dot gnu.org
@ 2012-06-08 22:42 ` gjl at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: gjl at gcc dot gnu.org @ 2012-06-08 22:42 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53256
--- Comment #4 from Georg-Johann Lay <gjl at gcc dot gnu.org> 2012-06-08 22:42:27 UTC ---
See also the following AVR-LibC bug report:
http://savannah.nongnu.org/bugs/index.php?26734
^ permalink raw reply [flat|nested] 6+ messages in thread
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