+/* Legitimize a memory reference for sync primitive implemented using
+ ldrex / strex. We currently force the form of the reference to be
+ indirect without offset. We do not yet support the indirect offset
+ addressing supported by some ARM targets for these
+ instructions. */
+static rtx
+arm_legitimize_sync_memory (rtx memory)
+{
+ rtx addr = force_reg (Pmode, XEXP (memory, 0));
+ rtx legitimate_memory = gen_rtx_MEM (GET_MODE (memory), addr);
+
+ set_mem_alias_set (legitimate_memory, ALIAS_SET_MEMORY_BARRIER);
+ MEM_VOLATILE_P (legitimate_memory) = MEM_VOLATILE_P (memory);
+ return legitimate_memory;
+}
+
+/* An instruction emitter. */
+typedef void (* emit_f) (int label, const char *, rtx *);
+
+/* An instruction emitter that emits via the conventional
+ output_asm_insn. */
+static void
+arm_emit (int label ATTRIBUTE_UNUSED, const char *pattern, rtx *operands)
+{
+ output_asm_insn (pattern, operands);
+}
+
+/* Count the number of emitted synchronization instructions. */
+static unsigned arm_insn_count;
+
+/* An emitter that counts emitted instructions but does not actually
+ emit instruction into the the instruction stream. */
+static void
+arm_count (int label,
+ const char *pattern ATTRIBUTE_UNUSED,
+ rtx *operands ATTRIBUTE_UNUSED)
+{
+ if (! label)
+ ++ arm_insn_count;
+}
+
+/* Construct a pattern using conventional output formatting and feed
+ it to output_asm_insn. Provides a mechanism to construct the
+ output pattern on the fly. Note the hard limit on the pattern
+ buffer size. */
+static void
+arm_output_asm_insn (emit_f emit, int label, rtx *operands,
+ const char *pattern, ...)
+{
+ va_list ap;
+ char buffer[256];
+
+ va_start (ap, pattern);
+ vsprintf (buffer, pattern, ap);
+ va_end (ap);
+ emit (label, buffer, operands);
+}
+
+/* Emit the memory barrier instruction, if any, provided by this
+ target to a specified emitter. */
+static void
+arm_process_output_memory_barrier (emit_f emit, rtx *operands)
+{
+ if (TARGET_HAVE_DMB)
+ {
+ /* Note we issue a system level barrier. We should consider
+ issuing a inner shareabilty zone barrier here instead, ie.
+ "DMB ISH". */
+ emit (0, "dmb\tsy", operands);
+ return;
+ }
+
+ if (TARGET_HAVE_DMB_MCR)
+ {
+ emit (0, "mcr\tp15, 0, r0, c7, c10, 5", operands);
+ return;
+ }
+
+ gcc_unreachable ();
+}
+
+/* Emit the memory barrier instruction, if any, provided by this
+ target. */
+const char *
+arm_output_memory_barrier (rtx *operands)
+{
+ arm_process_output_memory_barrier (arm_emit, operands);
+ return "";
+}
+
+/* Helper to figure out the instruction suffix required on ldrex/strex
+ for operations on an object of the specified mode. */
+static const char *
+arm_ldrex_suffix (enum machine_mode mode)
+{
+ switch (mode)
+ {
+ case QImode: return "b";
+ case HImode: return "h";
+ case SImode: return "";
+ case DImode: return "d";
+ default:
+ gcc_unreachable ();
+ }
+ return "";
+}
+
+/* Emit an ldrex{b,h,d, } instruction appropriate for the specified
+ mode. */
+static void
+arm_output_ldrex (emit_f emit,
+ enum machine_mode mode,
+ rtx target,
+ rtx memory)
+{
+ const char *suffix = arm_ldrex_suffix (mode);
+ rtx operands[2];
+
+ operands[0] = target;
+ operands[1] = memory;
+ arm_output_asm_insn (emit, 0, operands, "ldrex%s\t%%0, %%C1", suffix);
+}
+
+/* Emit a strex{b,h,d, } instruction appropriate for the specified
+ mode. */
+static void
+arm_output_strex (emit_f emit,
+ enum machine_mode mode,
+ const char *cc,
+ rtx result,
+ rtx value,
+ rtx memory)
+{
+ const char *suffix = arm_ldrex_suffix (mode);
+ rtx operands[3];
+
+ operands[0] = result;
+ operands[1] = value;
+ operands[2] = memory;
+ arm_output_asm_insn (emit, 0, operands, "strex%s%s\t%%0, %%1, %%C2", suffix,
+ cc);
+}
+
+/* Helper to emit a two operand instruction. */
+static void
+arm_output_op2 (emit_f emit, const char *mnemonic, rtx d, rtx s)
+{
+ rtx operands[2];
+
+ operands[0] = d;
+ operands[1] = s;
+ arm_output_asm_insn (emit, 0, operands, "%s\t%%0, %%1", mnemonic);
+}
+
+/* Helper to emit a three operand instruction. */
+static void
+arm_output_op3 (emit_f emit, const char *mnemonic, rtx d, rtx a, rtx b)
+{
+ rtx operands[3];
+
+ operands[0] = d;
+ operands[1] = a;
+ operands[2] = b;
+ arm_output_asm_insn (emit, 0, operands, "%s\t%%0, %%1, %%2", mnemonic);
+}
+
+/* Emit a load store exclusive synchronization loop.
+
+ do
+ old_value = [mem]
+ if old_value != required_value
+ break;
+ t1 = sync_op (old_value, new_value)
+ [mem] = t1, t2 = [0|1]
+ while ! t2
+
+ Note:
+ t1 == t2 is not permitted
+ t1 == old_value is permitted
+
+ required_value:
+
+ RTX register or const_int representing the required old_value for
+ the modify to continue, if NULL no comparsion is performed. */
+static void
+arm_output_sync_loop (emit_f emit,
+ enum machine_mode mode,
+ rtx old_value,
+ rtx memory,
+ rtx required_value,
+ rtx new_value,
+ rtx t1,
+ rtx t2,
+ enum attr_sync_op sync_op,
+ int early_barrier_required)
+{
+ rtx operands[1];
+
+ gcc_assert (t1 != t2);
+
+ if (early_barrier_required)
+ arm_process_output_memory_barrier (emit, NULL);
+
+ arm_output_asm_insn (emit, 1, operands, "%sLSYT%%=:", LOCAL_LABEL_PREFIX);
+
+ arm_output_ldrex (emit, mode, old_value, memory);
+
+ if (required_value)
+ {
+ rtx operands[2];
+
+ operands[0] = old_value;
+ operands[1] = required_value;
+ arm_output_asm_insn (emit, 0, operands, "cmp\t%%0, %%1");
+ arm_output_asm_insn (emit, 0, operands, "bne\t%sLSYB%%=", LOCAL_LABEL_PREFIX);
+ }
+
+ switch (sync_op)
+ {
+ case SYNC_OP_ADD:
+ arm_output_op3 (emit, "add", t1, old_value, new_value);
+ break;
+
+ case SYNC_OP_SUB:
+ arm_output_op3 (emit, "sub", t1, old_value, new_value);
+ break;
+
+ case SYNC_OP_IOR:
+ arm_output_op3 (emit, "orr", t1, old_value, new_value);
+ break;
+
+ case SYNC_OP_XOR:
+ arm_output_op3 (emit, "eor", t1, old_value, new_value);
+ break;
+
+ case SYNC_OP_AND:
+ arm_output_op3 (emit,"and", t1, old_value, new_value);
+ break;
+
+ case SYNC_OP_NAND:
+ arm_output_op3 (emit, "and", t1, old_value, new_value);
+ arm_output_op2 (emit, "mvn", t1, t1);
+ break;
+
+ case SYNC_OP_NONE:
+ t1 = new_value;
+ break;
+ }
+
+ arm_output_strex (emit, mode, "", t2, t1, memory);
+ operands[0] = t2;
+ arm_output_asm_insn (emit, 0, operands, "teq\t%%0, #0");
+ arm_output_asm_insn (emit, 0, operands, "bne\t%sLSYT%%=", LOCAL_LABEL_PREFIX);
+
+ arm_process_output_memory_barrier (emit, NULL);
+ arm_output_asm_insn (emit, 1, operands, "%sLSYB%%=:", LOCAL_LABEL_PREFIX);
+}
+
+static rtx
+arm_get_sync_operand (rtx *operands, int index, rtx default_value)
+{
+ if (index > 0)
+ default_value = operands[index - 1];
+
+ return default_value;
+}
+
+#define FETCH_SYNC_OPERAND(NAME, DEFAULT) \
+ arm_get_sync_operand (operands, (int) get_attr_sync_##NAME (insn), DEFAULT);
+
+/* Extract the operands for a synchroniztion instruction from the
+ instructions attributes and emit the instruction. */
+static void
+arm_process_output_sync_insn (emit_f emit, rtx insn, rtx *operands)
+{
+ rtx result, memory, required_value, new_value, t1, t2;
+ int early_barrier;
+ enum machine_mode mode;
+ enum attr_sync_op sync_op;
+
+ result = FETCH_SYNC_OPERAND(result, 0);
+ memory = FETCH_SYNC_OPERAND(memory, 0);
+ required_value = FETCH_SYNC_OPERAND(required_value, 0);
+ new_value = FETCH_SYNC_OPERAND(new_value, 0);
+ t1 = FETCH_SYNC_OPERAND(t1, 0);
+ t2 = FETCH_SYNC_OPERAND(t2, 0);
+ early_barrier =
+ get_attr_sync_release_barrier (insn) == SYNC_RELEASE_BARRIER_YES;
+ sync_op = get_attr_sync_op (insn);
+ mode = GET_MODE (memory);
+
+ arm_output_sync_loop (emit, mode, result, memory, required_value,
+ new_value, t1, t2, sync_op, early_barrier);
+}
+
+/* Emit a synchronization instruction loop. */
+const char *
+arm_output_sync_insn (rtx insn, rtx *operands)
+{
+ arm_process_output_sync_insn (arm_emit, insn, operands);
+ return "";
+}
+
+/* Count the number of machine instruction that will be emitted for a
+ synchronization instruction. Note that the emitter used does not
+ emit instructions, it just counts instructions being carefull not
+ to count labels. */
+unsigned int
+arm_sync_loop_insns (rtx insn, rtx *operands)
+{
+ arm_insn_count = 0;
+ arm_process_output_sync_insn (arm_count, insn, operands);
+ return arm_insn_count;
+}
+
+/* Helper to call a target sync instruction generator, dealing with
+ the variation in operands required by the different generators. */
+static rtx
+arm_call_generator (struct arm_sync_generator *generator, rtx old_value,
+ rtx memory, rtx required_value, rtx new_value)
+{
+ switch (generator->op)
+ {
+ case arm_sync_generator_omn:
+ gcc_assert (! required_value);
+ return generator->u.omn (old_value, memory, new_value);
+
+ case arm_sync_generator_omrn:
+ gcc_assert (required_value);
+ return generator->u.omrn (old_value, memory, required_value, new_value);
+ }
+
+ return NULL;
+}
+
+/* Expand a synchronization loop. The synchronization loop is expanded
+ as an opaque block of instructions in order to ensure that we do
+ not subsequently get extraneous memory accesses inserted within the
+ critical region. The exclusive access property of ldrex/strex is
+ only guaranteed in there are no intervening memory accesses. */
+void
+arm_expand_sync (enum machine_mode mode,
+ struct arm_sync_generator *generator,
+ rtx target, rtx memory, rtx required_value, rtx new_value)
+{
+ if (target == NULL)
+ target = gen_reg_rtx (mode);
+
+ memory = arm_legitimize_sync_memory (memory);
+ if (mode != SImode)
+ {
+ rtx load_temp = gen_reg_rtx (SImode);
+
+ if (required_value)
+ required_value = convert_modes (SImode, mode, required_value, true);
+
+ new_value = convert_modes (SImode, mode, new_value, true);
+ emit_insn (arm_call_generator (generator, load_temp, memory,
+ required_value, new_value));
+ emit_move_insn (target, gen_lowpart (mode, load_temp));
+ }
+ else
+ {
+ emit_insn (arm_call_generator (generator, target, memory, required_value,
+ new_value));
+ }
+}
+
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