[MIPS] Adding validator for MIPS architecture.

src/trusted/validator_mips/validation-report.py

+#!/usr/bin/python
+#
+# Copyright (c) 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.
+#
+
+

[Nick Bray (chromium), 2012/04/27 19:41:33]

One newline here.

+import sys
+import textwrap
+from subprocess import Popen, PIPE
+
+_OBJDUMP = 'mips-linux-gnu-objdump'
+

[Nick Bray (chromium), 2012/04/27 19:41:33]

Two newlines around functions and classes at module scope.

+def _objdump(binary, vaddr, ctx_before, ctx_after):
+    args = [
+        _OBJDUMP,
+        '-d',
+        '-G',
+        binary,
+        '--start-address=0x%08X' % (vaddr - (4 * ctx_before)),
+        '--stop-address=0x%08X' % (vaddr + 4 + (4 * ctx_after))]
+    highlight = ctx_before
+    lines = 0
+    for line in Popen(args, stdout=PIPE).stdout.read().split('\n'):
+        if line.startswith(' '):
+            if highlight == 0:
+                print '--> ', line
+            else:
+                print '    ', line
+            highlight -= 1
+            lines += 1
+    if not lines:
+        print '    (not found)'
+
+def _problem_info(code):
+    return {
+        'kProblemUnsafe': ['Instruction is unsafe', 0, 0],
+        'kProblemBranchSplitsPattern': ['The destination of this branch is '
+            'at middle of an pseudo-instruction that must be executed in full',
+            0, 0],
+        'kProblemPatternCrossesBundle': ['This instruction is part of a '
+            'sequence that must execute in full, but it spans a bundle edge '
+            '-- so an indirect branch may target it',
+            1, 1],
+        'kProblemBranchInvalidDest': ['This branch targets a location that is '
+            'outside of the application\'s executable code, over 256 MB',
+            0, 0],
+        'kProblemUnsafeLoadStore': ['This load/store instruction is not '
+            'preceded by a valid store mask instruction',
+            1, 0],
+        'kProblemUnsafeJumpRegister': ['This indirect jump instruction is not '
+            'preceded by a valid jump mask instruction',
+            1, 0],
+        'kProblemUnsafeDataWrite': ['This instruction affects a register that '
+            'must contain a valid data-region address (sp), but is not '
+            'followed by a valid store mask instruction',
+            0, 1],
+        'kProblemReadOnlyRegister': ['This instruction changes the contents of'
+            ' read-only register',
+            0, 0],
+        'kProblemMisalignedCall': ['This linking branch/jump instruction is '
+            'not at the bundle offset +8, so when its RA result is masked, the'
+            ' caller will not return to the next instruction (start of next '
+            'bundle)',
+            0, 0],
+        'kProblemUnalignedJumpToTrampoline':['The destination of this '
+            'jump/branch instruction is in trampoline code section but '
+            'address is not bundle aligned',
+            0, 0],
+        'kProblemDataRegInDelaySlot':['This instruction changes value of a '
+            'stack pointer but is located in the delay slot of jump/branch',
+            1, 0],
+    }[code]
+
+def _safety_msg(val):
+    return {
+        0: 'UNKNOWN',  # Should not appear
+        1: 'is undefined',
+        2: 'has unpredictable effects',
+        3: 'is deprecated',
+        4: 'is forbidden',
+        5: 'uses forbidden operands',
+    }[val]
+
+def _explain_problem(binary, vaddr, safety, code, ref_vaddr):
+    msg, ctx_before, ctx_after = _problem_info(code)
+    if safety == 6:
+        msg = "At %08X: %s:" % (vaddr, msg)
+    else:
+        msg = ("At %08X: %s (%s):"
+            % (vaddr, msg, _safety_msg(safety)))
+    print '\n'.join(textwrap.wrap(msg, 70, subsequent_indent='  '))
+    _objdump(binary, vaddr, ctx_before, ctx_after)
+    if ref_vaddr:
+        print "Destination address %08X:" % ref_vaddr
+        _objdump(binary, ref_vaddr, 1, 1)
+
+def _parse_report(line):
+    vaddr_hex, safety, code, ref_vaddr_hex = line.split()
+    return (int(vaddr_hex, 16), int(safety), code, int(ref_vaddr_hex, 16))
+
+for line in sys.stdin:

[Nick Bray (chromium), 2012/04/27 19:41:33]

Nit: Wrap inside a main() function, prevents the code from poluting the global
namespace.

+    if line.startswith('ncval: '):
+      line = line[7:].strip()
+      _explain_problem(sys.argv[1], *_parse_report(line))

[Nick Bray (chromium), 2012/04/27 19:41:33]

Nit: A little input validation here (len(sys.argv) == 2 and possibly
sys.path.exists(sys.argv[1])) might save a headache down the road.