h8300.h (READONLY_DATA_SECTION): Define.

        * h8300/h8300.h (READONLY_DATA_SECTION): Define.
        (EXTRA_SECTIONS): Add in_readonly_data.
        (READONLY_DATA_SECTION_ASM_OP): Define.
        (EXTRA_SECTION_FUNCTINOS): Add readonly_data.

From-SVN: r11951

diff --git a/gcc/config/h8300/h8300.h b/gcc/config/h8300/h8300.h
index 0b6667e..6109a85 100644 (file)
--- a/gcc/config/h8300/h8300.h
+++ b/gcc/config/h8300/h8300.h
@@ -1014,7 +1014,14 @@ h8300_valid_machine_decl_attribute (DECL, ATTRIBUTES, IDENTIFIER, ARGS)
 /* The assembler op to get a word, 2 bytes for the H8/300, 4 for H8/300H.  */
 #define ASM_WORD_OP    (TARGET_H8300 ? ".word" : ".long")
 
-/* Output before read-only data.  */
+/* We define a readonly data section solely to remove readonly data
+   from the instruction stream.  This can improve relaxing in two significant
+   ways.  First it's more likely that references to readonly data
+   can be done with a 16bit absolute address since they'll be in low
+   memory.  Second, it's more likely that jsr instructions can be
+   turned into bsr instructions since read-only data is not in the
+   instruction stream.  */
+#define READONLY_DATA_SECTION readonly_data
 
 #define TEXT_SECTION_ASM_OP "\t.section .text"
 #define DATA_SECTION_ASM_OP "\t.section .data"
@@ -1022,8 +1029,9 @@ h8300_valid_machine_decl_attribute (DECL, ATTRIBUTES, IDENTIFIER, ARGS)
 #define INIT_SECTION_ASM_OP "\t.section .init"
 #define CTORS_SECTION_ASM_OP "\t.section .ctors"
 #define DTORS_SECTION_ASM_OP "\t.section .dtors"
+#define READONLY_DATA_SECTION_ASM_OP "\t.section .rodata"
 
-#define EXTRA_SECTIONS in_ctors, in_dtors
+#define EXTRA_SECTIONS in_ctors, in_dtors, in_readonly_data
 
 #define EXTRA_SECTION_FUNCTIONS                                        \
                                                                \
@@ -1046,6 +1054,18 @@ dtors_section()                                          \
       in_section = in_dtors;                                   \
     }                                                          \
 }                                                              \
+                                                               \
+void                                                           \
+readonly_data()                                                \
+{                                                              \
+  if (in_section != in_readonly_data)                          \
+    {                                                          \
+      fprintf (asm_out_file, "%s\n", READONLY_DATA_SECTION_ASM_OP);\
+      in_section = in_readonly_data;                           \
+    }                                                          \
+}
+
+
 
 #define ASM_OUTPUT_CONSTRUCTOR(FILE,NAME)      \
   do { ctors_section();                                \