This is a port of an old patch of mine that got integrated in some
avr-gcc distributions.
Linking against __do_copy_data resp. __do_clear_bss is only needed if
there is actually stuff in .[ro]data resp. .bss. This saves some space
on tiny targets.
Regression-tested for C
Johann
2011-04-18 Georg-Johann Lay <a...@gjlay.de>
PR target/18145
* config/avr/avr.h (TARGET_ASM_INIT_SECTIONS): Move to
config/avr/avr.c
(TARGET_ASM_NAMED_SECTION): Change to avr_asm_named_section.
(ASM_OUTPUT_COMMON): Forward to avr_asm_output_common.
(ASM_OUTPUT_LOCAL): Forward to avr_asm_output_local.
* config/avr/avr-protos.h (avr_asm_output_common,
avr_asm_output_local): New prototypes.
* config/avr/avr.c .
(avr_asm_named_section, avr_asm_output_local,
avr_asm_output_common, avr_output_data_section_asm_op,
avr_output_bss_section_asm_op): New functions to update...
(avr_need_clear_bss_p, avr_need_copy_data_p): ...thise new variables.
(TARGET_ASM_INIT_SECTIONS): Overwrite section callbacks for
data_section, bss_section.
(avr_file_start): Move output of __do_copy_data, __do_clear_bss
from here to...
(avr_file_end): ...here.
Index: config/avr/avr-protos.h
===================================================================
--- config/avr/avr-protos.h (Revision 172597)
+++ config/avr/avr-protos.h (Arbeitskopie)
@@ -34,6 +34,8 @@ extern void gas_output_limited_string (F
extern void gas_output_ascii (FILE *file, const char *str, size_t length);
extern int avr_hard_regno_rename_ok (unsigned int, unsigned int);
extern rtx avr_return_addr_rtx (int count, rtx tem);
+extern void avr_asm_output_common (FILE*, const char*, unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT);
+extern void avr_asm_output_local (FILE*, const char*, unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT);
#ifdef TREE_CODE
extern void asm_output_external (FILE *file, tree decl, char *name);
Index: config/avr/avr.c
===================================================================
--- config/avr/avr.c (Revision 172597)
+++ config/avr/avr.c (Arbeitskopie)
@@ -108,6 +108,7 @@ static void avr_function_arg_advance (CU
const_tree, bool);
static void avr_help (void);
static bool avr_function_ok_for_sibcall (tree, tree);
+static void avr_asm_named_section (const char *name, unsigned int flags, tree decl);
/* Allocate registers from r25 to r8 for parameters for function calls. */
#define FIRST_CUM_REG 26
@@ -132,6 +133,10 @@ const struct mcu_type_s *avr_current_dev
section *progmem_section;
+/* To track if code will use .bss and/or .data */
+static int avr_need_clear_bss_p = 0;
+static int avr_need_copy_data_p = 0;
+
/* AVR attributes. */
static const struct attribute_spec avr_attribute_table[] =
{
@@ -197,6 +202,10 @@ static const struct default_options avr_
#define TARGET_INSERT_ATTRIBUTES avr_insert_attributes
#undef TARGET_SECTION_TYPE_FLAGS
#define TARGET_SECTION_TYPE_FLAGS avr_section_type_flags
+
+#undef TARGET_ASM_INIT_SECTIONS
+#define TARGET_ASM_INIT_SECTIONS avr_asm_init_sections
+
#undef TARGET_REGISTER_MOVE_COST
#define TARGET_REGISTER_MOVE_COST avr_register_move_cost
#undef TARGET_MEMORY_MOVE_COST
@@ -5190,6 +5199,65 @@ avr_output_progmem_section_asm_op (const
fprintf (asm_out_file, "\t.p2align 1\n");
}
+
+/* Implement `ASM_OUTPUT_LOCAL' */
+/* Track need of __do_clear_bss */
+
+void
+avr_asm_output_local (FILE * stream,
+ const char *name,
+ unsigned HOST_WIDE_INT size,
+ unsigned HOST_WIDE_INT rounded ATTRIBUTE_UNUSED)
+{
+ avr_need_clear_bss_p = 1;
+
+ fputs ("\t.lcomm ", stream);
+ assemble_name (stream, name);
+ fprintf (stream, ",%d\n", (int) size);
+}
+
+
+/* Implement `ASM_OUTPUT_COMMON' */
+/* Track need of __do_clear_bss */
+
+void
+avr_asm_output_common (FILE * stream,
+ const char *name,
+ unsigned HOST_WIDE_INT size,
+ unsigned HOST_WIDE_INT rounded ATTRIBUTE_UNUSED)
+{
+ avr_need_clear_bss_p = 1;
+
+ fputs ("\t.comm ", stream);
+ assemble_name (stream, name);
+ fprintf (stream, ",%lu,1\n", (unsigned long) size);
+}
+
+
+/* Unnamed section callback for data_section
+ to track need of __do_copy_data */
+
+static void
+avr_output_data_section_asm_op (const void *data)
+{
+ avr_need_copy_data_p = 1;
+ /* Dispatch to default */
+ output_section_asm_op (data);
+}
+
+
+/* Unnamed section callback for bss_section
+ to to track need of __do_clear_bss */
+
+static void
+avr_output_bss_section_asm_op (const void *data)
+{
+ avr_need_clear_bss_p = 1;
+ /* Dispatch to default */
+ output_section_asm_op (data);
+}
+
+
/* Implement TARGET_ASM_INIT_SECTIONS. */
static void
@@ -5199,6 +5267,27 @@ avr_asm_init_sections (void)
avr_output_progmem_section_asm_op,
NULL);
readonly_data_section = data_section;
+
+ data_section->unnamed.callback = avr_output_data_section_asm_op;
+ bss_section->unnamed.callback = avr_output_bss_section_asm_op;
+}
+
+
+/* Implement `TARGET_ASM_NAMED_SECTION' */
+/* Track need of __do_clear_bss, __do_copy_data for named sections */
+
+void
+avr_asm_named_section (const char *name, unsigned int flags, tree decl)
+{
+ if (!avr_need_copy_data_p)
+ avr_need_copy_data_p = ((0 == strncmp (name, ".data", 5)
+ || 0 == strncmp (name, ".rodata", 7)
+ || 0 == strncmp (name, ".gnu.linkonce.", 14)));
+
+ if (!avr_need_clear_bss_p)
+ avr_need_clear_bss_p = (0 == strncmp (name, ".bss", 4));
+
+ default_elf_asm_named_section (name, flags, decl);
}
static unsigned int
@@ -5237,12 +5326,6 @@ avr_file_start (void)
fputs ("__tmp_reg__ = 0\n"
"__zero_reg__ = 1\n", asm_out_file);
-
- /* FIXME: output these only if there is anything in the .data / .bss
- sections - some code size could be saved by not linking in the
- initialization code from libgcc if one or both sections are empty. */
- fputs ("\t.global __do_copy_data\n", asm_out_file);
- fputs ("\t.global __do_clear_bss\n", asm_out_file);
}
/* Outputs to the stdio stream FILE some
@@ -5251,6 +5334,17 @@ avr_file_start (void)
static void
avr_file_end (void)
{
+ /* Output these only if there is anything in the
+ .data* / .rodata* / .gnu.linkonce.* resp. .bss*
+ input section(s) - some code size can be saved by not
+ linking in the initialization code from libgcc if resp.
+ sections are empty. */
+
+ if (avr_need_copy_data_p)
+ fputs (".global __do_copy_data\n", asm_out_file);
+
+ if (avr_need_clear_bss_p)
+ fputs (".global __do_clear_bss\n", asm_out_file);
}
/* Choose the order in which to allocate hard registers for
Index: config/avr/avr.h
===================================================================
--- config/avr/avr.h (Revision 172597)
+++ config/avr/avr.h (Arbeitskopie)
@@ -460,29 +460,20 @@ do { \
#define ASM_APP_OFF "/* #NOAPP */\n"
/* Switch into a generic section. */
-#define TARGET_ASM_NAMED_SECTION default_elf_asm_named_section
-#define TARGET_ASM_INIT_SECTIONS avr_asm_init_sections
+#define TARGET_ASM_NAMED_SECTION avr_asm_named_section
#define ASM_OUTPUT_ASCII(FILE, P, SIZE) gas_output_ascii (FILE,P,SIZE)
#define IS_ASM_LOGICAL_LINE_SEPARATOR(C, STR) ((C) == '\n' || ((C) == '$'))
-#define ASM_OUTPUT_COMMON(STREAM, NAME, SIZE, ROUNDED) \
-do { \
- fputs ("\t.comm ", (STREAM)); \
- assemble_name ((STREAM), (NAME)); \
- fprintf ((STREAM), ",%lu,1\n", (unsigned long)(SIZE)); \
-} while (0)
+#define ASM_OUTPUT_COMMON(STREAM, NAME, SIZE, ROUNDED) \
+ avr_asm_output_common (STREAM, NAME, SIZE, ROUNDED)
#define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
-#define ASM_OUTPUT_LOCAL(STREAM, NAME, SIZE, ROUNDED) \
-do { \
- fputs ("\t.lcomm ", (STREAM)); \
- assemble_name ((STREAM), (NAME)); \
- fprintf ((STREAM), ",%d\n", (int)(SIZE)); \
-} while (0)
+#define ASM_OUTPUT_LOCAL(STREAM, NAME, SIZE, ROUNDED) \
+ avr_asm_output_local (STREAM, NAME, SIZE, ROUNDED)
#undef TYPE_ASM_OP
#undef SIZE_ASM_OP
