With the "noinit" attribute now handled generically, direct assignment of
data with the "noinit" attribute to the ".noinit" attribute can be removed from
the msp430 back end, and default_elf_select_section can be used instead.
default_elf_select_section can also be used for SECCAT_RODATA_MERGE_* sections,
to enable the linker to merge constant data.
>From 2d2bc7f11b7d5bfc918351a5963b041f69aac673 Mon Sep 17 00:00:00 2001
From: Jozef Lawrynowicz <joze...@mittosystems.com>
Date: Wed, 28 Aug 2019 17:54:22 +0100
Subject: [PATCH 3/3] MSP430: Use default_elf_select_section to determine
sections for data where possible
gcc/ChangeLog:
2019-08-29 Jozef Lawrynowicz <joze...@mittosystems.com>
* config/msp430/msp430.c (msp430_init_sections): Remove handling of the
noinit section.
(msp430_select_section): Handle decls with the "noinit" attribute with
default_elf_select_section.
Handle SECCAT_RODATA_MERGE_* section types with
default_elf_select_section.
Add comments about handling of unsupported section types.
(msp430_section_type_flags): Remove handling of the noinit section.
---
gcc/config/msp430/msp430.c | 81 +++++++++++++++++++++++---------------
1 file changed, 50 insertions(+), 31 deletions(-)
diff --git a/gcc/config/msp430/msp430.c b/gcc/config/msp430/msp430.c
index 1b2e9683a94..d409ea15df2 100644
--- a/gcc/config/msp430/msp430.c
+++ b/gcc/config/msp430/msp430.c
@@ -1785,7 +1785,6 @@ gen_prefix (tree decl)
return NULL;
}
-static section * noinit_section;
static section * persist_section;
#undef TARGET_ASM_INIT_SECTIONS
@@ -1794,8 +1793,6 @@ static section * persist_section;
static void
msp430_init_sections (void)
{
- noinit_section = get_unnamed_section (0, output_section_asm_op,
- ".section .noinit,\"aw\"");
persist_section = get_unnamed_section (0, output_section_asm_op,
".section .persistent,\"aw\"");
}
@@ -1806,6 +1803,10 @@ msp430_init_sections (void)
static section *
msp430_select_section (tree decl, int reloc, unsigned HOST_WIDE_INT align)
{
+ const char * prefix;
+ const char * sec_name;
+ const char * base_sec_name;
+
gcc_assert (decl != NULL_TREE);
if (TREE_CODE (decl) == STRING_CST
@@ -1821,51 +1822,71 @@ msp430_select_section (tree decl, int reloc, unsigned HOST_WIDE_INT align)
&& is_interrupt_func (decl))
return get_section (".lowtext", SECTION_CODE | SECTION_WRITE , decl);
- const char * prefix = gen_prefix (decl);
- if (prefix == NULL)
- {
- if (TREE_CODE (decl) == FUNCTION_DECL)
- return text_section;
- /* FIXME: ATTR_NOINIT is handled generically in
- default_elf_select_section. */
- else if (has_attr (ATTR_NOINIT, decl))
- return noinit_section;
- else if (has_attr (ATTR_PERSIST, decl))
- return persist_section;
- else
- return default_select_section (decl, reloc, align);
- }
+ if (has_attr (ATTR_PERSIST, decl))
+ return persist_section;
+
+ /* ATTR_NOINIT is handled generically. */
+ if (has_attr (ATTR_NOINIT, decl))
+ return default_elf_select_section (decl, reloc, align);
+
+ prefix = gen_prefix (decl);
- const char * sec;
switch (categorize_decl_for_section (decl, reloc))
{
- case SECCAT_TEXT: sec = ".text"; break;
- case SECCAT_DATA: sec = ".data"; break;
- case SECCAT_BSS: sec = ".bss"; break;
- case SECCAT_RODATA: sec = ".rodata"; break;
+ case SECCAT_TEXT:
+ if (!prefix)
+ return text_section;
+ base_sec_name = ".text";
+ break;
+ case SECCAT_DATA:
+ if (!prefix)
+ return data_section;
+ base_sec_name = ".data";
+ break;
+ case SECCAT_BSS:
+ if (!prefix)
+ return bss_section;
+ base_sec_name = ".bss";
+ break;
+ case SECCAT_RODATA:
+ if (!prefix)
+ return readonly_data_section;
+ base_sec_name = ".rodata";
+ break;
+ /* Enable merging of constant data by the GNU linker using
+ default_elf_select_section and therefore enabling creation of
+ sections with the SHF_MERGE flag. */
case SECCAT_RODATA_MERGE_STR:
case SECCAT_RODATA_MERGE_STR_INIT:
case SECCAT_RODATA_MERGE_CONST:
+ return default_elf_select_section (decl, reloc, align);
+
+ /* The sections listed below are are not supported for MSP430.
+ They should not be generated, but in case they are, we use
+ default_select_section so they get placed in sections
+ the msp430 assembler and linker understand. */
+ /* "small data" sections are not supported. */
case SECCAT_SRODATA:
- case SECCAT_DATA_REL:
- case SECCAT_DATA_REL_LOCAL:
- case SECCAT_DATA_REL_RO:
- case SECCAT_DATA_REL_RO_LOCAL:
case SECCAT_SDATA:
case SECCAT_SBSS:
+ /* Thread-local storage (TLS) is not supported. */
case SECCAT_TDATA:
case SECCAT_TBSS:
+ /* Sections used by a dynamic linker are not supported. */
+ case SECCAT_DATA_REL:
+ case SECCAT_DATA_REL_LOCAL:
+ case SECCAT_DATA_REL_RO:
+ case SECCAT_DATA_REL_RO_LOCAL:
return default_select_section (decl, reloc, align);
default:
gcc_unreachable ();
}
- const char * dec_name = DECL_SECTION_NAME (decl);
- char * name = ACONCAT ((prefix, sec, dec_name, NULL));
+ sec_name = ACONCAT ((prefix, base_sec_name, DECL_SECTION_NAME (decl), NULL));
- return get_named_section (decl, name, 0);
+ return get_named_section (decl, sec_name, 0);
}
#undef TARGET_ASM_FUNCTION_SECTION
@@ -1901,8 +1922,6 @@ msp430_section_type_flags (tree decl, const char * name, int reloc)
name += strlen (upper_prefix);
else if (strncmp (name, either_prefix, strlen (either_prefix)) == 0)
name += strlen (either_prefix);
- else if (strcmp (name, ".noinit") == 0)
- return SECTION_WRITE | SECTION_BSS | SECTION_NOTYPE;
else if (strcmp (name, ".persistent") == 0)
return SECTION_WRITE | SECTION_NOTYPE;
--
2.17.1
