[patch] m68k.h: Add "interrupt_thread" attribute.
Kazu Hirata
kazu@codesourcery.com
Fri Apr 27 17:15:00 GMT 2007
Hi,
Attached is a patch to add "interrupt_thread" attribute.
A function with the interrupt_thread attribute is compiled just like
an ordinary function except that
- no register is saved or restored in prologue/epilogue.
- the 'rts' instruction is replaced with the 'sleep' instruction.
This attribute is intended to take advantage of fido's hardware
contexts, implemented as five sets of registers. With this feature,
we can dedicate one context to handle a certain interrupt, presumably
time critical one where saving/restoring registers makes a big
difference.
As far as the implementation goes, we teach m68k_compute_frame_layout
to think that no register need saving/restoring when interrupt_thread
is specified.
Now that two different kinds of interrupt functions,
m68k_interrupt_function_p is renamed to m68k_get_function_kind,
categorizing functions into normal, interrupt_handler, and
interrupt_thread functions.
The output of the "*return" pattern and the attribute processing
should be self-explanatory.
Tested on fido-none-elf. OK to apply?
Kazu Hirata
gcc/
2007-04-27 Kazu Hirata <kazu@codesourcery.com>
* config/m68k/m68k-protos.h: Rename m68k_interrupt_function_p
to m68k_get_function_kind. Update its prototype.
* config/m68k/m68k.c (m68k_attribute_table): Add an entry for
interrupt_thread.
(m68k_interrupt_function_p): Return enum m68k_function_type
instead of bool. Rename to m68k_get_function_kind.
(m68k_handle_fndecl_attribute): Reject interrupt_thread if the
target is not fido.
(m68k_compute_frame_layout): Don't mark any register for save
if an interrupt_thread attribute is specified.
(m68k_hard_regno_rename_ok): Update a use of
m68k_interrupt_function_p.
* config/m68k/m68k.h (EPILOGUE_USES): Update a use of
m68k_interrupt_function_p.
(m68k_function_type): New.
* config/m68k/m68k.md (*return): Output a 'sleep' instruction
for a function with an interrupt_thread attribute.
* doc/extend.texi: Document the interrupt_thread attribute.
gcc/testsuite/
2007-04-27 Kazu Hirata <kazu@codesourcery.com>
* gcc.target/m68k/interrupt_thread-1.c,
gcc.target/m68k/interrupt_thread-2.c,
gcc.target/m68k/interrupt_thread-3.c: New.
* gcc.target/m68k/m68k.exp: Accept fido.
Index: gcc/config/m68k/m68k-protos.h
===================================================================
--- gcc/config/m68k/m68k-protos.h (revision 124112)
+++ gcc/config/m68k/m68k-protos.h (working copy)
@@ -21,7 +21,7 @@ Boston, MA 02110-1301, USA. */
/* Define functions defined in aux-output.c and used in templates. */
#ifdef RTX_CODE
-extern bool m68k_interrupt_function_p (tree);
+extern enum m68k_function_kind m68k_get_function_kind (tree);
extern HOST_WIDE_INT m68k_initial_elimination_offset (int from, int to);
extern void split_di (rtx[], int, rtx[], rtx[]);
Index: gcc/config/m68k/m68k.c
===================================================================
--- gcc/config/m68k/m68k.c (revision 124112)
+++ gcc/config/m68k/m68k.c (working copy)
@@ -223,6 +223,7 @@ static const struct attribute_spec m68k_
{
/* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler } */
{ "interrupt_handler", 0, 0, true, false, false, m68k_handle_fndecl_attribute },
+ { "interrupt_thread", 0, 0, true, false, false, m68k_handle_fndecl_attribute },
{ NULL, 0, 0, false, false, false, NULL }
};
@@ -633,10 +634,12 @@ m68k_cpp_cpu_family (const char *prefix)
return concat ("__m", prefix, "_family_", m68k_cpu_entry->family, NULL);
}
-/* Return nonzero if FUNC is an interrupt function as specified by the
- "interrupt_handler" attribute. */
-bool
-m68k_interrupt_function_p (tree func)
+/* Return m68k_fk_interrupt_handler if FUNC has an "interrupt_handler"
+ attribute and interrupt_thread if FUNC has an "interrupt_thread"
+ attribute. Otherwise, return m68k_fk_normal_function. */
+
+enum m68k_function_kind
+m68k_get_function_kind (tree func)
{
tree a;
@@ -644,7 +647,14 @@ m68k_interrupt_function_p (tree func)
return false;
a = lookup_attribute ("interrupt_handler", DECL_ATTRIBUTES (func));
- return (a != NULL_TREE);
+ if (a != NULL_TREE)
+ return m68k_fk_interrupt_handler;
+
+ a = lookup_attribute ("interrupt_thread", DECL_ATTRIBUTES (func));
+ if (a != NULL_TREE)
+ return m68k_fk_interrupt_thread;
+
+ return m68k_fk_normal_function;
}
/* Handle an attribute requiring a FUNCTION_DECL; arguments as in
@@ -662,6 +672,19 @@ m68k_handle_fndecl_attribute (tree *node
*no_add_attrs = true;
}
+ if (m68k_get_function_kind (*node) != m68k_fk_normal_function)
+ {
+ error ("multiple interrupt attributes not allowed");
+ *no_add_attrs = true;
+ }
+
+ if (!TARGET_FIDOA
+ && !strcmp (IDENTIFIER_POINTER (name), "interrupt_thread"))
+ {
+ error ("interrupt_thread is available only on fido");
+ *no_add_attrs = true;
+ }
+
return NULL_TREE;
}
@@ -670,7 +693,10 @@ m68k_compute_frame_layout (void)
{
int regno, saved;
unsigned int mask;
- bool interrupt_handler = m68k_interrupt_function_p (current_function_decl);
+ enum m68k_function_kind func_kind =
+ m68k_get_function_kind (current_function_decl);
+ bool interrupt_handler = func_kind == m68k_fk_interrupt_handler;
+ bool interrupt_thread = func_kind == m68k_fk_interrupt_thread;
/* Only compute the frame once per function.
Don't cache information until reload has been completed. */
@@ -681,12 +707,15 @@ m68k_compute_frame_layout (void)
current_frame.size = (get_frame_size () + 3) & -4;
mask = saved = 0;
- for (regno = 0; regno < 16; regno++)
- if (m68k_save_reg (regno, interrupt_handler))
- {
- mask |= 1 << (regno - D0_REG);
- saved++;
- }
+
+ /* Interrupt thread does not need to save any register. */
+ if (!interrupt_thread)
+ for (regno = 0; regno < 16; regno++)
+ if (m68k_save_reg (regno, interrupt_handler))
+ {
+ mask |= 1 << (regno - D0_REG);
+ saved++;
+ }
current_frame.offset = saved * 4;
current_frame.reg_no = saved;
current_frame.reg_mask = mask;
@@ -695,12 +724,14 @@ m68k_compute_frame_layout (void)
mask = saved = 0;
if (TARGET_HARD_FLOAT)
{
- for (regno = 16; regno < 24; regno++)
- if (m68k_save_reg (regno, interrupt_handler))
- {
- mask |= 1 << (regno - FP0_REG);
- saved++;
- }
+ /* Interrupt thread does not need to save any register. */
+ if (!interrupt_thread)
+ for (regno = 16; regno < 24; regno++)
+ if (m68k_save_reg (regno, interrupt_handler))
+ {
+ mask |= 1 << (regno - FP0_REG);
+ saved++;
+ }
current_frame.foffset = saved * TARGET_FP_REG_SIZE;
current_frame.offset += current_frame.foffset;
}
@@ -4212,7 +4243,8 @@ m68k_hard_regno_rename_ok (unsigned int
saved by the prologue, even if they would normally be
call-clobbered. */
- if (m68k_interrupt_function_p (current_function_decl)
+ if ((m68k_get_function_kind (current_function_decl)
+ == m68k_fk_interrupt_handler)
&& !regs_ever_live[new_reg])
return 0;
Index: gcc/config/m68k/m68k.h
===================================================================
--- gcc/config/m68k/m68k.h (revision 124112)
+++ gcc/config/m68k/m68k.h (working copy)
@@ -971,8 +971,10 @@ do { if (cc_prev_status.flags & CC_IN_68
#define INCOMING_FRAME_SP_OFFSET 4
/* All registers are live on exit from an interrupt routine. */
-#define EPILOGUE_USES(REGNO) \
- (reload_completed && m68k_interrupt_function_p (current_function_decl))
+#define EPILOGUE_USES(REGNO) \
+ (reload_completed \
+ && (m68k_get_function_kind (current_function_decl) \
+ == m68k_fk_interrupt_handler))
/* Describe how we implement __builtin_eh_return. */
#define EH_RETURN_DATA_REGNO(N) \
@@ -1166,6 +1168,13 @@ enum fpu_type
FPUTYPE_COLDFIRE
};
+enum m68k_function_kind
+{
+ m68k_fk_normal_function,
+ m68k_fk_interrupt_handler,
+ m68k_fk_interrupt_thread
+};
+
/* Variables in m68k.c; see there for details. */
extern const char *m68k_library_id_string;
extern int m68k_last_compare_had_fp_operands;
Index: gcc/config/m68k/m68k.md
===================================================================
--- gcc/config/m68k/m68k.md (revision 124112)
+++ gcc/config/m68k/m68k.md (working copy)
@@ -6832,15 +6832,23 @@ (define_insn "*return"
[(return)]
""
{
- if (m68k_interrupt_function_p (current_function_decl))
- return "rte";
- else if (current_function_pops_args)
+ switch (m68k_get_function_kind (current_function_decl))
{
- operands[0] = GEN_INT (current_function_pops_args);
- return "rtd %0";
+ case m68k_fk_interrupt_handler:
+ return "rte";
+
+ case m68k_fk_interrupt_thread:
+ return "sleep";
+
+ default:
+ if (current_function_pops_args)
+ {
+ operands[0] = GEN_INT (current_function_pops_args);
+ return "rtd %0";
+ }
+ else
+ return "rts";
}
- else
- return "rts";
})
(define_insn "*m68k_store_multiple"
Index: gcc/doc/extend.texi
===================================================================
--- gcc/doc/extend.texi (revision 124112)
+++ gcc/doc/extend.texi (working copy)
@@ -2013,6 +2013,14 @@ indicate that the specified function is
will generate function entry and exit sequences suitable for use in an
interrupt handler when this attribute is present.
+@item interrupt_thread
+@cindex interrupt thread functions on fido
+Use this attribute on fido, a subarchitecture of the m68k, to indicate
+that the specified function is an interrupt handler that is designed
+to run as a thread. The compiler omits generate prologue/epilogue
+sequences and replaces the return instruction with a @code{sleep}
+instruction. This attribute is available only on fido.
+
@item kspisusp
@cindex User stack pointer in interrupts on the Blackfin
When used together with @code{interrupt_handler}, @code{exception_handler}
Index: gcc/testsuite/gcc.target/m68k/interrupt_thread-1.c
===================================================================
--- gcc/testsuite/gcc.target/m68k/interrupt_thread-1.c (revision 0)
+++ gcc/testsuite/gcc.target/m68k/interrupt_thread-1.c (revision 0)
@@ -0,0 +1,43 @@
+/* { dg-do compile } */
+/* { dg-options "-mcpu=fidoa -O2 -fomit-frame-pointer" } */
+
+/* Check that interrupt_thread attribute works. */
+
+#ifdef __mfido__
+extern void foo (void) __attribute__ ((interrupt_thread));
+
+int a, b, c, d;
+
+void bar (void);
+
+void
+foo (void)
+{
+ int w, x, y, z;
+
+ w = a;
+ x = b;
+ y = c;
+ z = d;
+
+ bar ();
+
+ a = w;
+ b = x;
+ c = y;
+ d = z;
+}
+#else
+/* If the current mutilib is, say, -mcpu=5485, the compiler gets
+ -mcpu=fidoa -mcpu=5485, where -mcpu=fidoa is overridden. In that
+ case, we just print out "sleep" in the assembly file and pretend
+ that everything is all right. */
+asm ("sleep");
+#endif
+
+/* "sleep" should be generated in place of "rts". */
+/* { dg-final { scan-assembler-times "sleep" 1 } } */
+/* { dg-final { scan-assembler-times "rts" 0 } } */
+
+/* There should be no stack adjustment. */
+/* { dg-final { scan-assembler-times "sp" 0 } } */
Index: gcc/testsuite/gcc.target/m68k/interrupt_thread-2.c
===================================================================
--- gcc/testsuite/gcc.target/m68k/interrupt_thread-2.c (revision 0)
+++ gcc/testsuite/gcc.target/m68k/interrupt_thread-2.c (revision 0)
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-options "-mcpu=fidoa" } */
+
+/* Check that an error is issued for using more than one
+ interrupt_attribute at the same time. */
+
+/* If the current mutilib is, say, -mcpu=5485, the compiler gets
+ -mcpu=fidoa -mcpu=5485, where -mcpu=fidoa is overridden. In that
+ case, we just use two interrupt_handler attributes and expect the
+ same error. */
+#ifdef __mfido___
+#define IH interrupt_thread
+#else
+#define IH interrupt_handler
+#endif
+
+extern void f1 (void) __attribute__((interrupt_handler, interrupt_handler)); /* { dg-error "error: multiple interrupt attributes not allowed" } */
+
+extern void f2 (void) __attribute__((interrupt_handler, IH)); /* { dg-error "error: multiple interrupt attributes not allowed" } */
+
+extern void f3 (void) __attribute__((IH, interrupt_handler)); /* { dg-error "error: multiple interrupt attributes not allowed" } */
+
+extern void f4 (void) __attribute__((IH, IH)); /* { dg-error "error: multiple interrupt attributes not allowed" } */
Index: gcc/testsuite/gcc.target/m68k/interrupt_thread-3.c
===================================================================
--- gcc/testsuite/gcc.target/m68k/interrupt_thread-3.c (revision 0)
+++ gcc/testsuite/gcc.target/m68k/interrupt_thread-3.c (revision 0)
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-mcpu=cpu32" } */
+
+/* Check that interrupt_thread is rejected on CPUs other than
+ fido. */
+
+extern void foo (void) __attribute__((interrupt_thread)); /* { dg-error "error: interrupt_thread is available only on fido" } */
Index: gcc/testsuite/gcc.target/m68k/m68k.exp
===================================================================
--- gcc/testsuite/gcc.target/m68k/m68k.exp (revision 124112)
+++ gcc/testsuite/gcc.target/m68k/m68k.exp (working copy)
@@ -17,7 +17,7 @@
# GCC testsuite that uses the `dg.exp' driver.
# Exit immediately if this isn't an m68k target.
-if ![istarget m68k*-*-*] then {
+if { ![istarget m68k*-*-*] && ![istarget fido*-*-*] } then {
return
}
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