[MIPS] Adding validator for MIPS architecture.

src/trusted/validator_mips/testdata/test_loads.S

+# Copyright 2012 The Native Client Authors.  All rights reserved.
+# Use of this source code is governed by a BSD-style license that can
+# be found in the LICENSE file.
+
+# Several test cases are implemented in this file:
+# 1. Test if all load instructions are recognized as such.
+# 2. Test if load from sp is allowed.
+# 3. Test if mask and load instruction are split with delay slot.
+# 4. Test if mask and load instruction are in the same bundle.
+
+.globl _start
+_start:
+.align 4
+.set noreorder
+.set STORE_MASK,$t7
+
+   # Check masked load.
+
+   and     $a0, $a0, STORE_MASK
+   lw      $v0, 16($a0)               # OK
+   nop
+   nop
+
+   # Test if all load instructions are recognized as such.
+
+bundle_load_instrs:
+   lb      $a0, 4($a1)                # Error, unsafe load, no mask.
+   lw      $a0, 4($a1)                # Error, unsafe load, no mask.
+   lbu     $a0, 4($a1)                # Error, unsafe load, no mask.
+   ldc1    $f0, 4($a1)                # Error, unsafe load, no mask.
+
+   ldc2    $10, -24($a1)              # Error, unsafe load, no mask.
+   lh      $a0, 4($a1)                # Error, unsafe load, no mask.
+   lhu     $a0, 4($a1)                # Error, unsafe load, no mask.
+   ll      $a0, 4($a1)                # Error, unsafe load, no mask.
+
+   lw      $a0, 4($a1)                # Error, unsafe load, no mask.
+   lwc1    $f0, 4($a1)                # Error, unsafe load, no mask.
+   lwc2    $10, 4($a1)                # Error, unsafe load, no mask.
+   lwl     $a0, 4($a1)                # Error, unsafe load, no mask.
+
+   lwr     $a0, 4($a1)                # Error, unsafe load, no mask.
+   ldxc1   $f0, $0($a1)               # Forbidden instruction, unsafe load.
+   luxc1   $f0, $a2($a1)              # Forbidden instruction, unsafe load.
+   lwxc1   $f6, $v0($a1)              # Forbidden instruction, unsafe load.
+
+   # Test if load from sp is allowed.
+
+bundle_load_from_sp:
+   lw      $v0, 16($sp)               # OK
+   nop
+   and     $t2, $t2, STORE_MASK
+   lw      $t1, 16($t2)               # OK
+
+   # Test when load pseudo-instruction is split with delay slot.
+
+bundle_chk_delay_slot:
+   b       bundle_chk_bundle_cross_1
+    and    $s0, $s0, STORE_MASK       # OK
+   lw      $a0, 16($s0)
+   nop
+
+   # Test when load pseudo-instruction crosses bundle.
+
+bundle_chk_bundle_cross_1:
+   nop
+   nop
+   nop
+   and     $a3, $a3, STORE_MASK
+
+
+bundle_chk_bundle_cross_2:
+   lw      $a3, 16($a3)               # Error, pattern crosses bundle.
+   nop
+   nop
+   nop
+
+   lbux    $a3, $t2($t3)              # Error, forbidden instruction.
+   lhx     $a1, $a2($a3)              # Error, forbidden instruction.
+   lwx     $t1, $t2($t3)              # Error, forbidden instruction.
+   nop
+
+end_of_code: