Senthil Kumar Selvaraj schrieb:
Hi,
This patch fixes PR 71151 by eliminating the
TARGET_ASM_FUNCTION_RODATA_SECTION hook and setting
JUMP_TABLES_IN_TEXT_SECTION to 1.
As described in the bugzilla entry, this hook assumed it will get
called only for jumptable rodata for functions. This was true until
6.1, when a commit in varasm.c started calling the hook for mergeable
string/constant data as well.
This resulted in string constants ending up in a section intended for
jumptables (flash), and broke code using those constants, which
expects them to be present in rodata (SRAM).
Given that the original reason for placing jumptables in a section was
fixed by Johann in PR 63323, this patch restores the original
behavior. Reg testing on both gcc-6-branch and trunk showed no regressions.
As pointed out by Johann, this may end up increasing code
size if there are lots of branches that cross the jump tables. I
intend to propose a separate patch that gives additional information
to the target hook (SECCAT_RODATA_{STRING,JUMPTABLE}) so it can know
what type of function rodata is coming on. Johann also suggested
handling jump table generation ourselves - I'll experiment with that
some more.
If ok, could someone commit please? Could you also backport to
gcc-6-branch?
Regards
Senthil
gcc/ChangeLog
2016-06-03 Senthil Kumar Selvaraj <senthil_kumar.selva...@atmel.com>
* config/avr/avr.c (avr_asm_function_rodata_section): Remove.
* config/avr/avr.c (TARGET_ASM_FUNCTION_RODATA_SECTION): Remove.
gcc/testsuite/ChangeLog
2016-06-03 Senthil Kumar Selvaraj <senthil_kumar.selva...@atmel.com>
* gcc/testsuite/gcc.target/avr/pr71151-1.c: New.
* gcc/testsuite/gcc.target/avr/pr71151-2.c: New.
diff --git gcc/config/avr/avr.c gcc/config/avr/avr.c
index ba5cd91..3cb8cb7 100644
--- gcc/config/avr/avr.c
+++ gcc/config/avr/avr.c
@@ -9488,65 +9488,6 @@ avr_asm_init_sections (void)
}
-/* Implement `TARGET_ASM_FUNCTION_RODATA_SECTION'. */
-
-static section*
-avr_asm_function_rodata_section (tree decl)
-{
- /* If a function is unused and optimized out by -ffunction-sections
- and --gc-sections, ensure that the same will happen for its jump
- tables by putting them into individual sections. */
-
- unsigned int flags;
- section * frodata;
-
- /* Get the frodata section from the default function in varasm.c
- but treat function-associated data-like jump tables as code
- rather than as user defined data. AVR has no constant pools. */
- {
- int fdata = flag_data_sections;
-
- flag_data_sections = flag_function_sections;
- frodata = default_function_rodata_section (decl);
- flag_data_sections = fdata;
- flags = frodata->common.flags;
- }
-
- if (frodata != readonly_data_section
- && flags & SECTION_NAMED)
- {
- /* Adjust section flags and replace section name prefix. */
-
- unsigned int i;
-
- static const char* const prefix[] =
- {
- ".rodata", ".progmem.gcc_sw_table",
- ".gnu.linkonce.r.", ".gnu.linkonce.t."
- };
-
- for (i = 0; i < sizeof (prefix) / sizeof (*prefix); i += 2)
- {
- const char * old_prefix = prefix[i];
- const char * new_prefix = prefix[i+1];
- const char * name = frodata->named.name;
-
- if (STR_PREFIX_P (name, old_prefix))
- {
- const char *rname = ACONCAT ((new_prefix,
- name + strlen (old_prefix), NULL));
- flags &= ~SECTION_CODE;
- flags |= AVR_HAVE_JMP_CALL ? 0 : SECTION_CODE;
-
- return get_section (rname, flags, frodata->named.decl);
- }
- }
- }
-
- return progmem_swtable_section;
The progmem_swtable_section is no more needed; the code to set it up can
also be removed.
Johann
-}
-
-
/* Implement `TARGET_ASM_NAMED_SECTION'. */
/* Track need of __do_clear_bss, __do_copy_data for named sections. */
@@ -13747,9 +13688,6 @@ avr_fold_builtin (tree fndecl, int n_args ATTRIBUTE_UNUSED, tree *arg,
#undef TARGET_FOLD_BUILTIN
#define TARGET_FOLD_BUILTIN avr_fold_builtin
-#undef TARGET_ASM_FUNCTION_RODATA_SECTION
-#define TARGET_ASM_FUNCTION_RODATA_SECTION avr_asm_function_rodata_section
-
#undef TARGET_SCALAR_MODE_SUPPORTED_P
#define TARGET_SCALAR_MODE_SUPPORTED_P avr_scalar_mode_supported_p
diff --git gcc/config/avr/avr.h gcc/config/avr/avr.h
index 01da708..ab5e465 100644
--- gcc/config/avr/avr.h
+++ gcc/config/avr/avr.h
@@ -391,7 +391,7 @@ typedef struct avr_args
#define SUPPORTS_INIT_PRIORITY 0
-#define JUMP_TABLES_IN_TEXT_SECTION 0
+#define JUMP_TABLES_IN_TEXT_SECTION 1
#define ASM_COMMENT_START " ; "
diff --git gcc/testsuite/gcc.target/avr/pr71151-1.c gcc/testsuite/gcc.target/avr/pr71151-1.c
new file mode 100644
index 0000000..615dce8
--- /dev/null
+++ gcc/testsuite/gcc.target/avr/pr71151-1.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-Os -ffunction-sections -fdata-sections" } */
+
+/* { dg-final { scan-assembler-not ".section
.progmem.gcc_sw_table.foo.str1.1" } } */
+/* { dg-final { scan-assembler ".section .rodata.foo.str1.1,\"aMS\"" } } */
+
+
+extern void bar(const char*);
+void foo(void)
+{
+ bar("BBBBBBBBBB");
+}
diff --git gcc/testsuite/gcc.target/avr/pr71151-2.c
gcc/testsuite/gcc.target/avr/pr71151-2.c
new file mode 100644
index 0000000..0041858
--- /dev/null
+++ gcc/testsuite/gcc.target/avr/pr71151-2.c
@@ -0,0 +1,49 @@
+/* { dg-do run } */
+/* { dg-options "-Os -ffunction-sections -fdata-sections" } */
+
+/* Make sure jumptables work properly, after removing the
+ special section placement hook. */
+
+#include "exit-abort.h"
+
+volatile char y;
+volatile char g;
+
+void foo(char x)
+{
+ switch (x)
+ {
+ case 0:
+ y = 67; break;
+ case 1:
+ y = 20; break;
+ case 2:
+ y = 109; break;
+ case 3:
+ y = 33; break;
+ case 4:
+ y = 44; break;
+ case 5:
+ y = 37; break;
+ case 6:
+ y = 10; break;
+ case 7:
+ y = 98; break;
+ }
+ y = y + g;
+}
+
+int main()
+{
+ foo(5);
+ if (y != 37)
+ abort();
+
+ foo(0);
+ if (y != 67)
+ abort();
+
+ foo(7);
+ if (y != 98)
+ abort();
+}
