mirror of
git://gcc.gnu.org/git/gcc.git
synced 2025-03-20 06:30:28 +08:00
f0033821c1
Similar to what already exists for TI msp430 or in TI compilers for
arm, this patch adds support for the "noinit" attribute.
It is convenient for embedded targets where the user wants to keep the
value of some data when the program is restarted: such variables are
not zero-initialized. It is mostly a helper/shortcut to placing
variables in a dedicated section.
It's probably desirable to add the following chunk to the GNU linker:
diff --git a/ld/emulparams/armelf.sh b/ld/emulparams/armelf.sh
index 272a8bc..9555cec 100644
--- a/ld/emulparams/armelf.sh
+++ b/ld/emulparams/armelf.sh
@@ -10,7 +10,19 @@ OTHER_TEXT_SECTIONS='*(.glue_7t) *(.glue_7)
*(.vfp11_veneer) *(.v4_bx)'
OTHER_BSS_SYMBOLS="${CREATE_SHLIB+PROVIDE (}__bss_start__ =
.${CREATE_SHLIB+)};"
OTHER_BSS_END_SYMBOLS="${CREATE_SHLIB+PROVIDE (}_bss_end__ =
.${CREATE_SHLIB+)}; ${CREATE_SHLIB+PROVIDE (}__bss_end__ =
.${CREATE_SHLIB+)};"
OTHER_END_SYMBOLS="${CREATE_SHLIB+PROVIDE (}__end__ = .${CREATE_SHLIB+)};"
-OTHER_SECTIONS='.note.gnu.arm.ident 0 : { KEEP (*(.note.gnu.arm.ident)) }'
+OTHER_SECTIONS='
+.note.gnu.arm.ident 0 : { KEEP (*(.note.gnu.arm.ident)) }
+ /* This section contains data that is not initialised during load
+ *or* application reset. */
+ .noinit (NOLOAD) :
+ {
+ . = ALIGN(2);
+ PROVIDE (__noinit_start = .);
+ *(.noinit)
+ . = ALIGN(2);
+ PROVIDE (__noinit_end = .);
+ }
+'
so that the noinit section has the "NOLOAD" flag.
I added a testcase if gcc.c-torture/execute, gated by the new noinit
effective-target.
Finally, I tested on arm-eabi, but not on msp430 for which I do not
have the environment.
gcc/ChangeLog:
2019-08-14 Christophe Lyon <christophe.lyon@linaro.org>
* doc/extend.texi: Add "noinit" attribute documentation.
* doc/sourcebuild.texi: Add noinit effective target documentation.
* varasm.c (default_section_type_flags): Add support for "noinit" section.
(default_elf_select_section): Add support for "noinit" attribute.
* config/msp430/msp430.c (msp430_attribute_table): Remove "noinit" entry.
gcc/c-family/ChangeLog:
2019-08-14 Christophe Lyon <christophe.lyon@linaro.org>
* c-attribs.c (c_common_attribute_table): Add "noinit" entry. Add
exclusion with "section" attribute.
(attr_noinit_exclusions): New table.
(handle_noinit_attribute): New function.
gcc/testsuite/ChangeLog:
2019-08-14 Christophe Lyon <christophe.lyon@linaro.org>
* lib/target-supports.exp (check_effective_target_noinit): New
proc.
* gcc.c-torture/execute/noinit-attribute.c: New test.
From-SVN: r274482
This directory contains the GNU Compiler Collection (GCC). The GNU Compiler Collection is free software. See the files whose names start with COPYING for copying permission. The manuals, and some of the runtime libraries, are under different terms; see the individual source files for details. The directory INSTALL contains copies of the installation information as HTML and plain text. The source of this information is gcc/doc/install.texi. The installation information includes details of what is included in the GCC sources and what files GCC installs. See the file gcc/doc/gcc.texi (together with other files that it includes) for usage and porting information. An online readable version of the manual is in the files gcc/doc/gcc.info*. See http://gcc.gnu.org/bugs/ for how to report bugs usefully. Copyright years on GCC source files may be listed using range notation, e.g., 1987-2012, indicating that every year in the range, inclusive, is a copyrightable year that could otherwise be listed individually.