This implements static stack checking for MIPS, i.e. checking of the static
part of the frame in the prologue when -fstack-check is specified. This is
very similar to the PowerPC and SPARC implementations and makes it possible to
pass the full ACATS testsuite with -fstack-check.
Tested on mips64el-linux-gnu (n32/32/64), OK for the mainline?
2012-10-21 Eric Botcazou <ebotca...@adacore.com>
* config/mips/linux-common.h (STACK_CHECK_STATIC_BUILTIN): Define.
(STACK_CHECK_PROTECT): Likewise.
* config/mips/mips-protos.h (mips_output_probe_stack_range): Declare.
* config/mips/mips.c: Include common/common-target.h.
(mips_emit_probe_stack_range): New function.
(mips_output_probe_stack_range): Likewise.
(mips_expand_prologue): Invoke mips_emit_probe_stack_range if static
builtin stack checking is enabled.
* config/mips/mips.md (UNSPEC_PROBE_STACK_RANGE): New constant.
(probe_stack_range<P:mode>): New insn.
ada/
* system-linux-mipsel.ads (Stack_Check_Probes): Set to True.
* system-linux-mips.ads (Stack_Check_Probes): Likewise.
* system-linux-mips64el.ads (Stack_Check_Probes): Likewise.
--
Eric BotcazouIndex: config/mips/mips.md
===================================================================
--- config/mips/mips.md (revision 192648)
+++ config/mips/mips.md (working copy)
@@ -137,6 +137,9 @@ (define_c_enum "unspec" [
;; MIPS16 casesi jump table dispatch.
UNSPEC_CASESI_DISPATCH
+
+ ;; Stack checking.
+ UNSPEC_PROBE_STACK_RANGE
])
(define_constants
@@ -6040,6 +6043,17 @@ (define_insn "blockage"
[(set_attr "type" "ghost")
(set_attr "mode" "none")])
+(define_insn "probe_stack_range<P:mode>"
+ [(set (match_operand:P 0 "register_operand" "=r")
+ (unspec_volatile:P [(match_operand:P 1 "register_operand" "0")
+ (match_operand:P 2 "register_operand" "r")]
+ UNSPEC_PROBE_STACK_RANGE))]
+ ""
+ "* return mips_output_probe_stack_range (operands[0], operands[2]);"
+ [(set_attr "type" "unknown")
+ (set_attr "can_delay" "no")
+ (set_attr "mode" "<MODE>")])
+
(define_expand "epilogue"
[(const_int 2)]
""
Index: config/mips/linux-common.h
===================================================================
--- config/mips/linux-common.h (revision 192648)
+++ config/mips/linux-common.h (working copy)
@@ -56,3 +56,9 @@ along with GCC; see the file COPYING3.
GNU_USER_TARGET_ENDFILE_SPEC, \
GNU_USER_TARGET_MATHFILE_SPEC " " \
ANDROID_ENDFILE_SPEC)
+
+/* Define this to be nonzero if static stack checking is supported. */
+#define STACK_CHECK_STATIC_BUILTIN 1
+
+/* The default value isn't sufficient in 64-bit mode. */
+#define STACK_CHECK_PROTECT (TARGET_64BIT ? 16 * 1024 : 12 * 1024)
Index: config/mips/mips-protos.h
===================================================================
--- config/mips/mips-protos.h (revision 192648)
+++ config/mips/mips-protos.h (working copy)
@@ -316,6 +316,7 @@ extern const char *mips_output_sync (voi
extern const char *mips_output_sync_loop (rtx, rtx *);
extern unsigned int mips_sync_loop_insns (rtx, rtx *);
extern const char *mips_output_division (const char *, rtx *);
+extern const char *mips_output_probe_stack_range (rtx, rtx);
extern unsigned int mips_hard_regno_nregs (int, enum machine_mode);
extern bool mips_linked_madd_p (rtx, rtx);
extern bool mips_store_data_bypass_p (rtx, rtx);
Index: config/mips/mips.c
===================================================================
--- config/mips/mips.c (revision 192648)
+++ config/mips/mips.c (working copy)
@@ -50,6 +50,7 @@ along with GCC; see the file COPYING3.
#include "debug.h"
#include "target.h"
#include "target-def.h"
+#include "common/common-target.h"
#include "langhooks.h"
#include "sched-int.h"
#include "gimple.h"
@@ -10613,6 +10614,144 @@ mips_emit_loadgp (void)
emit_insn (gen_loadgp_blockage ());
}
+#define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
+
+#if PROBE_INTERVAL > 32768
+#error Cannot use indexed addressing mode for stack probing
+#endif
+
+/* Emit code to probe a range of stack addresses from FIRST to FIRST+SIZE,
+ inclusive. These are offsets from the current stack pointer. */
+
+static void
+mips_emit_probe_stack_range (HOST_WIDE_INT first, HOST_WIDE_INT size)
+{
+ /* See if we have a constant small number of probes to generate. If so,
+ that's the easy case. */
+ if (first + size <= 32768)
+ {
+ HOST_WIDE_INT i;
+
+ /* 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 < size; i += PROBE_INTERVAL)
+ emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
+ -(first + i)));
+
+ emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
+ -(first + size)));
+ }
+
+ /* Otherwise, 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
+ {
+ HOST_WIDE_INT rounded_size;
+ rtx r3 = gen_rtx_REG (Pmode, GP_REG_FIRST + 3);
+ rtx r12 = gen_rtx_REG (Pmode, GP_REG_FIRST + 12);
+
+ /* Sanity check for the addressing mode we're going to use. */
+ gcc_assert (first <= 32768);
+
+
+ /* Step 1: round SIZE to the previous multiple of the interval. */
+
+ rounded_size = size & -PROBE_INTERVAL;
+
+
+ /* Step 2: compute initial and final value of the loop counter. */
+
+ /* TEST_ADDR = SP + FIRST. */
+ emit_insn (gen_rtx_SET (VOIDmode, r3,
+ plus_constant (Pmode, stack_pointer_rtx,
+ -first)));
+
+ /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
+ if (rounded_size > 32768)
+ {
+ emit_move_insn (r12, GEN_INT (rounded_size));
+ emit_insn (gen_rtx_SET (VOIDmode, r12,
+ gen_rtx_MINUS (Pmode, r3, r12)));
+ }
+ else
+ emit_insn (gen_rtx_SET (VOIDmode, r12,
+ plus_constant (Pmode, r3, -rounded_size)));
+
+
+ /* 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. */
+
+ if (TARGET_64BIT && TARGET_LONG64)
+ emit_insn (gen_probe_stack_rangedi (r3, r3, r12));
+ else
+ emit_insn (gen_probe_stack_rangesi (r3, r3, r12));
+
+
+ /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
+ that SIZE is equal to ROUNDED_SIZE. */
+
+ if (size != rounded_size)
+ emit_stack_probe (plus_constant (Pmode, r12, rounded_size - size));
+ }
+
+ /* Make sure nothing is scheduled before we are done. */
+ emit_insn (gen_blockage ());
+}
+
+/* Probe a range of stack addresses from REG1 to REG2 inclusive. These are
+ absolute addresses. */
+
+const char *
+mips_output_probe_stack_range (rtx reg1, rtx reg2)
+{
+ static int labelno = 0;
+ char loop_lab[32], end_lab[32], tmp[64];
+ rtx xops[2];
+
+ ASM_GENERATE_INTERNAL_LABEL (loop_lab, "LPSRL", labelno);
+ ASM_GENERATE_INTERNAL_LABEL (end_lab, "LPSRE", labelno++);
+
+ ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, loop_lab);
+
+ /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
+ xops[0] = reg1;
+ xops[1] = reg2;
+ strcpy (tmp, "beq\t%0,%1,");
+ output_asm_insn (strcat (tmp, &end_lab[1]), xops);
+
+ /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
+ xops[1] = GEN_INT (-PROBE_INTERVAL);
+ if (TARGET_64BIT && TARGET_LONG64)
+ output_asm_insn (" daddiu\t%0,%0,%1", xops);
+ else
+ output_asm_insn (" addiu\t%0,%0,%1", xops);
+
+ /* Probe at TEST_ADDR and branch. */
+ fprintf (asm_out_file, "\tb\t");
+ assemble_name_raw (asm_out_file, loop_lab);
+ fputc ('\n', asm_out_file);
+ if (TARGET_64BIT)
+ output_asm_insn (" sd\t$0,0(%0)", xops);
+ else
+ output_asm_insn (" sw\t$0,0(%0)", xops);
+
+ ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, end_lab);
+
+ return "";
+}
+
/* A for_each_rtx callback. Stop the search if *X is a kernel register. */
static int
@@ -10652,6 +10791,9 @@ mips_expand_prologue (void)
if (flag_stack_usage_info)
current_function_static_stack_size = size;
+ if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK && size)
+ mips_emit_probe_stack_range (STACK_CHECK_PROTECT, size);
+
/* Save the registers. Allocate up to MIPS_MAX_FIRST_STACK_STEP
bytes beforehand; this is enough to cover the register save area
without going out of range. */
Index: ada/system-linux-mipsel.ads
===================================================================
--- ada/system-linux-mipsel.ads (revision 192648)
+++ ada/system-linux-mipsel.ads (working copy)
@@ -7,7 +7,7 @@
-- S p e c --
-- (GNU-Linux/MIPSEL Version) --
-- --
--- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2012, Free Software Foundation, Inc. --
-- --
-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. The copyright notice above, and the license provisions that follow --
@@ -128,7 +128,7 @@ private
Preallocated_Stacks : constant Boolean := False;
Signed_Zeros : constant Boolean := True;
Stack_Check_Default : constant Boolean := False;
- Stack_Check_Probes : constant Boolean := False;
+ Stack_Check_Probes : constant Boolean := True;
Stack_Check_Limits : constant Boolean := False;
Support_64_Bit_Divides : constant Boolean := True;
Support_Aggregates : constant Boolean := True;
Index: ada/system-linux-mips.ads
===================================================================
--- ada/system-linux-mips.ads (revision 192648)
+++ ada/system-linux-mips.ads (working copy)
@@ -7,7 +7,7 @@
-- S p e c --
-- (GNU-Linux/MIPS Version) --
-- --
--- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2012, Free Software Foundation, Inc. --
-- --
-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. The copyright notice above, and the license provisions that follow --
@@ -128,7 +128,7 @@ private
Preallocated_Stacks : constant Boolean := False;
Signed_Zeros : constant Boolean := True;
Stack_Check_Default : constant Boolean := False;
- Stack_Check_Probes : constant Boolean := False;
+ Stack_Check_Probes : constant Boolean := True;
Stack_Check_Limits : constant Boolean := False;
Support_64_Bit_Divides : constant Boolean := True;
Support_Aggregates : constant Boolean := True;
Index: ada/system-linux-mips64el.ads
===================================================================
--- ada/system-linux-mips64el.ads (revision 192648)
+++ ada/system-linux-mips64el.ads (working copy)
@@ -7,7 +7,7 @@
-- S p e c --
-- (GNU-Linux/MIPS64EL Version) --
-- --
--- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2012, Free Software Foundation, Inc. --
-- --
-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. The copyright notice above, and the license provisions that follow --
@@ -128,7 +128,7 @@ private
Preallocated_Stacks : constant Boolean := False;
Signed_Zeros : constant Boolean := True;
Stack_Check_Default : constant Boolean := False;
- Stack_Check_Probes : constant Boolean := False;
+ Stack_Check_Probes : constant Boolean := True;
Stack_Check_Limits : constant Boolean := False;
Support_64_Bit_Divides : constant Boolean := True;
Support_Aggregates : constant Boolean := True;
