static rtx break_out_memory_refs (rtx);
static void emit_stack_probe (rtx);
+static void anti_adjust_stack_and_probe (rtx);
/* Truncate and perhaps sign-extend C as appropriate for MODE. */
gcc_assert (!(stack_pointer_delta
% (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)));
- /* If needed, check that we have the required amount of stack.
- Take into account what has already been checked. */
- if (flag_stack_check == GENERIC_STACK_CHECK)
+ /* If needed, check that we have the required amount of stack. Take into
+ account what has already been checked. */
+ if (STACK_CHECK_MOVING_SP)
+ ;
+ else if (flag_stack_check == GENERIC_STACK_CHECK)
probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE,
size);
else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK)
emit_label (space_available);
}
- anti_adjust_stack (size);
+ if (flag_stack_check && STACK_CHECK_MOVING_SP)
+ anti_adjust_stack_and_probe (size);
+ else
+ anti_adjust_stack (size);
#ifdef STACK_GROWS_DOWNWARD
emit_move_insn (target, virtual_stack_dynamic_rtx);
MEM_VOLATILE_P (memref) = 1;
+ /* See if we have an insn to probe the stack. */
+#ifdef HAVE_probe_stack
+ if (HAVE_probe_stack)
+ emit_insn (gen_probe_stack (memref));
+ else
+#endif
if (STACK_CHECK_PROBE_LOAD)
emit_move_insn (gen_reg_rtx (word_mode), memref);
else
}
/* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
- FIRST is a constant and size is a Pmode RTX. These are offsets from the
- current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
- subtract from the stack. If SIZE is constant, this is done
- with a fixed number of probes. Otherwise, we must make a loop. */
+ FIRST is a constant and size is a Pmode RTX. These are offsets from
+ the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
+ or subtract them from the stack pointer. */
+
+#define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
#ifdef STACK_GROWS_DOWNWARD
#define STACK_GROW_OP MINUS
+#define STACK_GROW_OPTAB sub_optab
+#define STACK_GROW_OFF(off) -(off)
#else
#define STACK_GROW_OP PLUS
+#define STACK_GROW_OPTAB add_optab
+#define STACK_GROW_OFF(off) (off)
#endif
void
if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
size = convert_to_mode (Pmode, size, 1);
- /* Next see if the front end has set up a function for us to call to
- check the stack. */
- if (stack_check_libfunc != 0)
+ /* Next see if we have a function to check the stack. */
+ if (stack_check_libfunc)
{
- rtx addr = memory_address (QImode,
+ rtx addr = memory_address (Pmode,
gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
stack_pointer_rtx,
plus_constant (size, first)));
-
- addr = convert_memory_address (ptr_mode, addr);
- emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
- ptr_mode);
+ emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr);
}
- /* Next see if we have an insn to check the stack. Use it if so. */
+ /* Next see if we have an insn to check the stack. */
#ifdef HAVE_check_stack
else if (HAVE_check_stack)
{
- insn_operand_predicate_fn pred;
- rtx last_addr
- = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
- stack_pointer_rtx,
- plus_constant (size, first)),
- NULL_RTX);
-
- pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
- if (pred && ! ((*pred) (last_addr, Pmode)))
- last_addr = copy_to_mode_reg (Pmode, last_addr);
+ rtx addr = memory_address (Pmode,
+ gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
+ stack_pointer_rtx,
+ plus_constant (size, first)));
+ insn_operand_predicate_fn pred
+ = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
+ if (pred && !((*pred) (addr, Pmode)))
+ addr = copy_to_mode_reg (Pmode, addr);
- emit_insn (gen_check_stack (last_addr));
+ emit_insn (gen_check_stack (addr));
}
#endif
- /* If we have to generate explicit probes, see if we have a constant
- small number of them to generate. If so, that's the easy case. */
- else if (CONST_INT_P (size)
- && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
+ /* Otherwise we have to generate explicit probes. If we have a constant
+ small number of them to generate, that's the easy case. */
+ else if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
{
- HOST_WIDE_INT offset;
-
- /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
- for values of N from 1 until it exceeds LAST. If only one
- probe is needed, this will not generate any code. Then probe
- at LAST. */
- for (offset = first + STACK_CHECK_PROBE_INTERVAL;
- offset < INTVAL (size);
- offset = offset + STACK_CHECK_PROBE_INTERVAL)
- emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
- stack_pointer_rtx,
- GEN_INT (offset)));
-
- emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
- stack_pointer_rtx,
- plus_constant (size, first)));
+ HOST_WIDE_INT isize = INTVAL (size), i;
+ rtx addr;
+
+ /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until
+ it exceeds SIZE. If only one probe is needed, this will not
+ generate any code. Then probe at FIRST + SIZE. */
+ for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
+ {
+ addr = memory_address (Pmode,
+ plus_constant (stack_pointer_rtx,
+ STACK_GROW_OFF (first + i)));
+ emit_stack_probe (addr);
+ }
+
+ addr = memory_address (Pmode,
+ plus_constant (stack_pointer_rtx,
+ STACK_GROW_OFF (first + isize)));
+ emit_stack_probe (addr);
}
- /* In the variable case, do the same as above, but in a loop. We emit loop
- notes so that loop optimization can be done. */
+ /* In the variable case, do the same as above, but in a loop. Note that we
+ must be extra careful with variables wrapping around because we might be
+ at the very top (or the very bottom) of the address space and we have to
+ be able to handle this case properly; in particular, we use an equality
+ test for the loop condition. */
else
{
- rtx test_addr
- = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
- stack_pointer_rtx,
- GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
- NULL_RTX);
- rtx last_addr
- = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
- stack_pointer_rtx,
- plus_constant (size, first)),
- NULL_RTX);
- rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
+ rtx rounded_size, rounded_size_op, test_addr, last_addr, temp;
rtx loop_lab = gen_label_rtx ();
- rtx test_lab = gen_label_rtx ();
rtx end_lab = gen_label_rtx ();
- rtx temp;
- if (!REG_P (test_addr)
- || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
- test_addr = force_reg (Pmode, test_addr);
- emit_jump (test_lab);
+ /* Step 1: round SIZE to the previous multiple of the interval. */
+
+ /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
+ rounded_size
+ = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL));
+ rounded_size_op = force_operand (rounded_size, NULL_RTX);
+
+
+ /* Step 2: compute initial and final value of the loop counter. */
+
+ /* TEST_ADDR = SP + FIRST. */
+ test_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
+ stack_pointer_rtx,
+ GEN_INT (first)), NULL_RTX);
+
+ /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
+ last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
+ test_addr,
+ rounded_size_op), NULL_RTX);
+
+
+ /* Step 3: the loop
+
+ while (TEST_ADDR != LAST_ADDR)
+ {
+ TEST_ADDR = TEST_ADDR + PROBE_INTERVAL
+ probe at TEST_ADDR
+ }
+
+ probes at FIRST + N * PROBE_INTERVAL for values of N from 1
+ until it is equal to ROUNDED_SIZE. */
emit_label (loop_lab);
- emit_stack_probe (test_addr);
-#ifdef STACK_GROWS_DOWNWARD
-#define CMP_OPCODE GTU
- temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
- 1, OPTAB_WIDEN);
-#else
-#define CMP_OPCODE LTU
- temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
+ /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
+ emit_cmp_and_jump_insns (test_addr, last_addr, EQ, NULL_RTX, Pmode, 1,
+ end_lab);
+
+ /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
+ temp = expand_binop (Pmode, STACK_GROW_OPTAB, test_addr,
+ GEN_INT (PROBE_INTERVAL), test_addr,
1, OPTAB_WIDEN);
-#endif
gcc_assert (temp == test_addr);
- emit_label (test_lab);
- emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
- NULL_RTX, Pmode, 1, loop_lab);
- emit_jump (end_lab);
+ /* Probe at TEST_ADDR. */
+ emit_stack_probe (test_addr);
+
+ emit_jump (loop_lab);
+
emit_label (end_lab);
- emit_stack_probe (last_addr);
+
+ /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
+ that SIZE is equal to ROUNDED_SIZE. */
+
+ /* TEMP = SIZE - ROUNDED_SIZE. */
+ temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
+ if (temp != const0_rtx)
+ {
+ rtx addr;
+
+ if (GET_CODE (temp) == CONST_INT)
+ {
+ /* Use [base + disp} addressing mode if supported. */
+ HOST_WIDE_INT offset = INTVAL (temp);
+ addr = memory_address (Pmode,
+ plus_constant (last_addr,
+ STACK_GROW_OFF (offset)));
+ }
+ else
+ {
+ /* Manual CSE if the difference is not known at compile-time. */
+ temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
+ addr = memory_address (Pmode,
+ gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
+ last_addr, temp));
+ }
+
+ emit_stack_probe (addr);
+ }
}
}
-\f
+
+/* Adjust the stack by SIZE bytes while probing it. Note that we skip the
+ probe for the first interval + a small dope of 4 words and instead probe
+ that many bytes past the specified size to maintain a protection area. */
+
+static void
+anti_adjust_stack_and_probe (rtx size)
+{
+ const int dope = 4 * UNITS_PER_WORD;
+
+ /* First ensure SIZE is Pmode. */
+ if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
+ size = convert_to_mode (Pmode, size, 1);
+
+ /* If we have a constant small number of probes to generate, that's the
+ easy case. */
+ if (GET_CODE (size) == CONST_INT && INTVAL (size) < 7 * PROBE_INTERVAL)
+ {
+ HOST_WIDE_INT isize = INTVAL (size), i;
+ bool first_probe = true;
+
+ /* Adjust SP and probe to PROBE_INTERVAL + N * PROBE_INTERVAL for
+ values of N from 1 until it exceeds SIZE. If only one probe is
+ needed, this will not generate any code. Then adjust and probe
+ to PROBE_INTERVAL + SIZE. */
+ for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
+ {
+ if (first_probe)
+ {
+ anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL + dope));
+ first_probe = false;
+ }
+ else
+ anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
+ emit_stack_probe (stack_pointer_rtx);
+ }
+
+ if (first_probe)
+ anti_adjust_stack (plus_constant (size, PROBE_INTERVAL + dope));
+ else
+ anti_adjust_stack (plus_constant (size, PROBE_INTERVAL - i));
+ emit_stack_probe (stack_pointer_rtx);
+ }
+
+ /* In the variable case, do the same as above, but in a loop. Note that we
+ must be extra careful with variables wrapping around because we might be
+ at the very top (or the very bottom) of the address space and we have to
+ be able to handle this case properly; in particular, we use an equality
+ test for the loop condition. */
+ else
+ {
+ rtx rounded_size, rounded_size_op, last_addr, temp;
+ rtx loop_lab = gen_label_rtx ();
+ rtx end_lab = gen_label_rtx ();
+
+
+ /* Step 1: round SIZE to the previous multiple of the interval. */
+
+ /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
+ rounded_size
+ = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL));
+ rounded_size_op = force_operand (rounded_size, NULL_RTX);
+
+
+ /* Step 2: compute initial and final value of the loop counter. */
+
+ /* SP = SP_0 + PROBE_INTERVAL. */
+ anti_adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
+
+ /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */
+ last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
+ stack_pointer_rtx,
+ rounded_size_op), NULL_RTX);
+
+
+ /* Step 3: the loop
+
+ while (SP != LAST_ADDR)
+ {
+ SP = SP + PROBE_INTERVAL
+ probe at SP
+ }
+
+ adjusts SP and probes to PROBE_INTERVAL + N * PROBE_INTERVAL for
+ values of N from 1 until it is equal to ROUNDED_SIZE. */
+
+ emit_label (loop_lab);
+
+ /* Jump to END_LAB if SP == LAST_ADDR. */
+ emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
+ Pmode, 1, end_lab);
+
+ /* SP = SP + PROBE_INTERVAL and probe at SP. */
+ anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
+ emit_stack_probe (stack_pointer_rtx);
+
+ emit_jump (loop_lab);
+
+ emit_label (end_lab);
+
+
+ /* Step 4: adjust SP and probe to PROBE_INTERVAL + SIZE if we cannot
+ assert at compile-time that SIZE is equal to ROUNDED_SIZE. */
+
+ /* TEMP = SIZE - ROUNDED_SIZE. */
+ temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
+ if (temp != const0_rtx)
+ {
+ /* Manual CSE if the difference is not known at compile-time. */
+ if (GET_CODE (temp) != CONST_INT)
+ temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
+ anti_adjust_stack (temp);
+ emit_stack_probe (stack_pointer_rtx);
+ }
+ }
+
+ /* Adjust back to account for the additional first interval. */
+ adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
+}
+
/* Return an rtx representing the register or memory location
in which a scalar value of data type VALTYPE
was returned by a function call to function FUNC.
projects / platform / upstream / linaro-gcc.git / commitdiff