gcc for xtensa always aligns data at least to a word boundary, even when
it has smaller natural alignment. This results in unexpectedly high data
section sizes and unreasonable amount of wasted space when linking
objects compiled with -fdata-sections flag.
Align data naturally when optimization for size is enabled.
2015-02-22 Max Filippov <jcmvb...@gmail.com>
gcc/
* config/xtensa/xtensa.h (CONSTANT_ALIGNMENT, DATA_ALIGNMENT):
use natural alignment when optimizing for size.
---
gcc/config/xtensa/xtensa.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/gcc/config/xtensa/xtensa.h b/gcc/config/xtensa/xtensa.h
index 0de072b..74ca240 100644
--- a/gcc/config/xtensa/xtensa.h
+++ b/gcc/config/xtensa/xtensa.h
@@ -174,7 +174,8 @@ extern unsigned xtensa_current_frame_size;
constants to be word aligned so that 'strcpy' calls that copy
constants can be done inline. */
#define CONSTANT_ALIGNMENT(EXP, ALIGN) \
- ((TREE_CODE (EXP) == STRING_CST || TREE_CODE (EXP) == CONSTRUCTOR) \
+ (!optimize_size && \
+ (TREE_CODE (EXP) == STRING_CST || TREE_CODE (EXP) == CONSTRUCTOR) \
&& (ALIGN) < BITS_PER_WORD \
? BITS_PER_WORD \
: (ALIGN))
@@ -186,7 +187,7 @@ extern unsigned xtensa_current_frame_size;
that copy constants to character arrays can be done inline. */
#undef DATA_ALIGNMENT
#define DATA_ALIGNMENT(TYPE, ALIGN) \
- ((((ALIGN) < BITS_PER_WORD) \
+ (!optimize_size && (((ALIGN) < BITS_PER_WORD)
\
&& (TREE_CODE (TYPE) == ARRAY_TYPE \
|| TREE_CODE (TYPE) == UNION_TYPE \
|| TREE_CODE (TYPE) == RECORD_TYPE)) ? BITS_PER_WORD : (ALIGN))
--
1.8.1.4
