Hi,
Since PR71151 we have jump-tables in .text so that branches
crossing the tables have longer offsets that needed.
This moves jump-tables out of test again, but not into
.progmem.gcc_sw_tables like before PR71151, but into
the currently unused but existing .jumptables.
Since PR63223 there is no restriction on the location
of jump-tables, they can even reside above 128KiB without
problems.
Also adds -mlog=insn_addresses to dump insn addresses
as asm comments before respective instruction.
The patch implements ASM_OUTPUT_ADDR_VEC so that avr.c
gains full control over the table generation.
Tested on ATmega2560.
Ok to apply?
Johann
gcc/
Move jump-tables out of .text again.
PR target/81075
* config/avr/avr.c (ASM_OUTPUT_ADDR_VEC_ELT): Remove function.
(ASM_OUTPUT_ADDR_VEC): New function.
(avr_adjust_insn_length) [JUMP_TABLE_DATA_P]: Return 0.
(avr_final_prescan_insn) [avr_log.insn_addresses]: Dump
INSN_ADDRESSes as asm comment.
* config/avr/avr.h (JUMP_TABLES_IN_TEXT_SECTION): Adjust comment.
(ASM_OUTPUT_ADDR_VEC_ELT): Remove define.
(ASM_OUTPUT_ADDR_VEC): Define to avr_output_addr_vec.
* config/avr/avr.md (*tablejump): Adjust comment.
* config/avr/elf.h (ASM_OUTPUT_BEFORE_CASE_LABEL): Remove.
* config/avr/avr-log.c (avr_log_set_avr_log) <insn_addresses>:
New detail.
* config/avr/avr-protos.h (avr_output_addr_vec_elt): Remove proto.
(avr_output_addr_vec): New proto.
(avr_log_t) <insn_addresses>: New field.
Index: config/avr/avr-log.c
===================================================================
--- config/avr/avr-log.c (revision 249121)
+++ config/avr/avr-log.c (working copy)
@@ -302,6 +302,7 @@ avr_log_set_avr_log (void)
SET_DUMP_DETAIL (address_cost);
SET_DUMP_DETAIL (builtin);
SET_DUMP_DETAIL (constraints);
+ SET_DUMP_DETAIL (insn_addresses);
SET_DUMP_DETAIL (legitimate_address_p);
SET_DUMP_DETAIL (legitimize_address);
SET_DUMP_DETAIL (legitimize_reload_address);
Index: config/avr/avr-protos.h
===================================================================
--- config/avr/avr-protos.h (revision 249121)
+++ config/avr/avr-protos.h (working copy)
@@ -87,7 +87,7 @@ extern bool avr_emit_movmemhi (rtx*);
extern int avr_epilogue_uses (int regno);
extern int avr_starting_frame_offset (void);
-extern void avr_output_addr_vec_elt (FILE *stream, int value);
+extern void avr_output_addr_vec (rtx_insn*, rtx);
extern const char *avr_out_sbxx_branch (rtx_insn *insn, rtx operands[]);
extern const char* avr_out_bitop (rtx, rtx*, int*);
extern const char* avr_out_plus (rtx, rtx*, int* =NULL, int* =NULL, bool =true);
@@ -175,6 +175,7 @@ typedef struct
unsigned address_cost :1;
unsigned builtin :1;
unsigned constraints :1;
+ unsigned insn_addresses :1;
unsigned legitimate_address_p :1;
unsigned legitimize_address :1;
unsigned legitimize_reload_address :1;
Index: config/avr/avr.c
===================================================================
--- config/avr/avr.c (revision 249124)
+++ config/avr/avr.c (working copy)
@@ -3088,6 +3088,10 @@ avr_final_prescan_insn (rtx_insn *insn,
rtx_cost (PATTERN (insn), VOIDmode, INSN, 0,
optimize_insn_for_speed_p()));
}
+
+ if (avr_log.insn_addresses)
+ fprintf (asm_out_file, ";; ADDR = %d\n",
+ (int) INSN_ADDRESSES (INSN_UID (insn)));
}
/* Return 0 if undefined, 1 if always true or always false. */
@@ -9138,6 +9142,12 @@ avr_adjust_insn_length (rtx_insn *insn,
rtx *op = recog_data.operand;
enum attr_adjust_len adjust_len;
+ /* As we pretend jump tables in .text, fix branch offsets crossing jump
+ tables now. */
+
+ if (JUMP_TABLE_DATA_P (insn))
+ return 0;
+
/* Some complex insns don't need length adjustment and therefore
the length need not/must not be adjusted for these insns.
It is easier to state this in an insn attribute "adjust_len" than
@@ -12309,17 +12319,88 @@ avr_out_reload_inpsi (rtx *op, rtx clobb
}
-/* Worker function for `ASM_OUTPUT_ADDR_VEC_ELT'. */
+/* Worker function for `ASM_OUTPUT_ADDR_VEC'. */
+/* Emit jump tables out-of-line so that branches crossing the table
+ get shorter offsets. If we have JUMP + CALL, then put the tables
+ in a dedicated non-.text section so that CALLs get better chance to
+ be relaxed to RCALLs.
+
+ We emit the tables by hand because `function_rodata_section' does not
+ work as expected, cf. PR71151, and we do *NOT* want the table to be
+ in .rodata, hence setting JUMP_TABLES_IN_TEXT_SECTION = 0 is of limited
+ use; and setting it to 1 attributes table lengths to branch offsets...
+ Moreover, fincal.c keeps switching section before each table entry
+ which we find too fragile as to rely on section caching. */
void
-avr_output_addr_vec_elt (FILE *stream, int value)
+avr_output_addr_vec (rtx_insn *labl, rtx table)
{
- if (AVR_HAVE_JMP_CALL)
- fprintf (stream, "\t.word gs(.L%d)\n", value);
+ FILE *stream = asm_out_file;
+
+ app_disable();
+
+ // Switch to appropriate (sub)section.
+
+ if (DECL_SECTION_NAME (current_function_decl)
+ && symtab_node::get (current_function_decl)
+ && ! symtab_node::get (current_function_decl)->implicit_section)
+ {
+ // .subsection will emit the code after the function and in the
+ // section as chosen by the user.
+
+ switch_to_section (current_function_section ());
+ fprintf (stream, "\t.subsection\t1\n");
+ }
else
- fprintf (stream, "\trjmp .L%d\n", value);
+ {
+ // Since PR63223 there is no restriction where to put the table; it
+ // may even reside above 128 KiB. We put it in a section as high as
+ // possible and avoid progmem in order not to waste flash <= 64 KiB.
+
+ const char *sec_name = ".jumptables.gcc";
+
+ // The table belongs to its host function, therefore use fine
+ // grained sections so that, if that function is removed by
+ // --gc-sections, the child table(s) may also be removed. */
+
+ tree asm_name = DECL_ASSEMBLER_NAME (current_function_decl);
+ const char *fname = IDENTIFIER_POINTER (asm_name);
+ fname = targetm.strip_name_encoding (fname);
+ sec_name = ACONCAT ((sec_name, ".", fname, NULL));
+
+ fprintf (stream, "\t.section\t%s,\"%s\",@progbits\n", sec_name,
+ AVR_HAVE_JMP_CALL ? "a" : "ax");
+ }
+
+ // Output the label that preceeds the table.
+
+ ASM_OUTPUT_ALIGN (stream, 1);
+ targetm.asm_out.internal_label (stream, "L", CODE_LABEL_NUMBER (labl));
+
+ // Output the table's content.
+
+ int vlen = XVECLEN (table, 0);
+
+ for (int idx = 0; idx < vlen; idx++)
+ {
+ int value = CODE_LABEL_NUMBER (XEXP (XVECEXP (table, 0, idx), 0));
+
+ if (AVR_HAVE_JMP_CALL)
+ fprintf (stream, "\t.word gs(.L%d)\n", value);
+ else
+ fprintf (stream, "\trjmp .L%d\n", value);
+ }
+
+ // Switch back to original section. As we clobbered the section above,
+ // forget the current section before switching back.
+
+ in_section = NULL;
+ switch_to_section (current_function_section ());
}
+
+/* Implement `TARGET_CONDITIONAL_REGISTER_USAGE'. */
+
static void
avr_conditional_register_usage (void)
{
Index: config/avr/avr.h
===================================================================
--- config/avr/avr.h (revision 249124)
+++ config/avr/avr.h (working copy)
@@ -398,6 +398,10 @@ typedef struct avr_args
#define SUPPORTS_INIT_PRIORITY 0
+/* We pretend jump tables are in text section because otherwise,
+ final.c will switch to .rodata before jump tables and thereby
+ triggers __do_copy_data. As we implement ASM_OUTPUT_ADDR_VEC,
+ we still have full control over the jump tables themselves. */
#define JUMP_TABLES_IN_TEXT_SECTION 1
#define ASM_COMMENT_START " ; "
@@ -447,8 +451,8 @@ typedef struct avr_args
fprintf (STREAM, "\tpop\tr%d", REGNO); \
}
-#define ASM_OUTPUT_ADDR_VEC_ELT(STREAM, VALUE) \
- avr_output_addr_vec_elt (STREAM, VALUE)
+#define ASM_OUTPUT_ADDR_VEC(TLABEL, TDATA) \
+ avr_output_addr_vec (TLABEL, TDATA)
#define ASM_OUTPUT_ALIGN(STREAM, POWER) \
do { \
Index: config/avr/avr.md
===================================================================
--- config/avr/avr.md (revision 249121)
+++ config/avr/avr.md (working copy)
@@ -5185,7 +5185,7 @@ (define_insn "*indirect_jump"
(set_attr "cc" "none")])
;; table jump
-;; For entries in jump table see avr_output_addr_vec_elt.
+;; For entries in jump table see avr_output_addr_vec.
;; Table made from
;; "rjmp .L<n>" instructions for <= 8K devices
Index: config/avr/elf.h
===================================================================
--- config/avr/elf.h (revision 249121)
+++ config/avr/elf.h (working copy)
@@ -31,11 +31,6 @@
#undef STRING_LIMIT
#define STRING_LIMIT ((unsigned) 64)
-/* Output alignment 2**1 for jump tables. */
-#undef ASM_OUTPUT_BEFORE_CASE_LABEL
-#define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE, PREFIX, NUM, TABLE) \
- ASM_OUTPUT_ALIGN (FILE, 1);
-
/* Be conservative in crtstuff.c. */
#undef INIT_SECTION_ASM_OP
#undef FINI_SECTION_ASM_OP
