Add m-esr52 at 52.6.0

1 files changed, 890 insertions, 0 deletions

diff --git a/memory/replace/dmd/dmd.py b/memory/replace/dmd/dmd.py
new file mode 100755
index 000000000..d6b09f756
--- /dev/null
+++ b/memory/replace/dmd/dmd.py
@@ -0,0 +1,890 @@
+#! /usr/bin/env python
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+'''This script analyzes a JSON file emitted by DMD.'''
+
+from __future__ import print_function, division
+
+import argparse
+import collections
+import gzip
+import json
+import os
+import platform
+import re
+import shutil
+import sys
+import tempfile
+from bisect import bisect_right
+
+# The DMD output version this script handles.
+outputVersion = 5
+
+# If --ignore-alloc-fns is specified, stack frames containing functions that
+# match these strings will be removed from the *start* of stack traces. (Once
+# we hit a non-matching frame, any subsequent frames won't be removed even if
+# they do match.)
+allocatorFns = [
+    # Matches malloc, replace_malloc, moz_xmalloc, vpx_malloc, js_malloc, pod_malloc, malloc_zone_*, g_malloc.
+    'malloc',
+    # Matches calloc, replace_calloc, moz_xcalloc, vpx_calloc, js_calloc, pod_calloc, malloc_zone_calloc, pod_callocCanGC.
+    'calloc',
+    # Matches realloc, replace_realloc, moz_xrealloc, vpx_realloc, js_realloc, pod_realloc, pod_reallocCanGC.
+    'realloc',
+    # Matches memalign, posix_memalign, replace_memalign, replace_posix_memalign, moz_xmemalign, moz_xposix_memalign, vpx_memalign, malloc_zone_memalign.
+    'memalign',
+    'operator new(',
+    'operator new[](',
+    'g_slice_alloc',
+    # This one necessary to fully filter some sequences of allocation functions
+    # that happen in practice. Note that ??? entries that follow non-allocation
+    # functions won't be stripped, as explained above.
+    '???',
+]
+
+class Record(object):
+    '''A record is an aggregation of heap blocks that have identical stack
+    traces. It can also be used to represent the difference between two
+    records.'''
+
+    def __init__(self):
+        self.numBlocks = 0
+        self.reqSize = 0
+        self.slopSize = 0
+        self.usableSize = 0
+        self.allocatedAtDesc = None
+        self.reportedAtDescs = []
+        self.usableSizes = collections.defaultdict(int)
+
+    def isZero(self, args):
+        return self.numBlocks == 0 and \
+               self.reqSize == 0 and \
+               self.slopSize == 0 and \
+               self.usableSize == 0 and \
+               len(self.usableSizes) == 0
+
+    def negate(self):
+        self.numBlocks = -self.numBlocks
+        self.reqSize = -self.reqSize
+        self.slopSize = -self.slopSize
+        self.usableSize = -self.usableSize
+
+        negatedUsableSizes = collections.defaultdict(int)
+        for usableSize, count in self.usableSizes.items():
+            negatedUsableSizes[-usableSize] = count
+        self.usableSizes = negatedUsableSizes
+
+    def subtract(self, r):
+        # We should only be calling this on records with matching stack traces.
+        # Check this.
+        assert self.allocatedAtDesc == r.allocatedAtDesc
+        assert self.reportedAtDescs == r.reportedAtDescs
+
+        self.numBlocks -= r.numBlocks
+        self.reqSize -= r.reqSize
+        self.slopSize -= r.slopSize
+        self.usableSize -= r.usableSize
+
+        usableSizes1 = self.usableSizes
+        usableSizes2 = r.usableSizes
+        usableSizes3 = collections.defaultdict(int)
+        for usableSize in usableSizes1:
+            counts1 = usableSizes1[usableSize]
+            if usableSize in usableSizes2:
+                counts2 = usableSizes2[usableSize]
+                del usableSizes2[usableSize]
+                counts3 = counts1 - counts2
+                if counts3 != 0:
+                    if counts3 < 0:
+                        usableSize = -usableSize
+                        counts3 = -counts3
+                    usableSizes3[usableSize] = counts3
+            else:
+                usableSizes3[usableSize] = counts1
+
+        for usableSize in usableSizes2:
+            usableSizes3[-usableSize] = usableSizes2[usableSize]
+
+        self.usableSizes = usableSizes3
+
+    @staticmethod
+    def cmpByUsableSize(r1, r2):
+        # Sort by usable size, then by req size.
+        return cmp(abs(r1.usableSize), abs(r2.usableSize)) or \
+               Record.cmpByReqSize(r1, r2)
+
+    @staticmethod
+    def cmpByReqSize(r1, r2):
+        # Sort by req size.
+        return cmp(abs(r1.reqSize), abs(r2.reqSize))
+
+    @staticmethod
+    def cmpBySlopSize(r1, r2):
+        # Sort by slop size.
+        return cmp(abs(r1.slopSize), abs(r2.slopSize))
+
+    @staticmethod
+    def cmpByNumBlocks(r1, r2):
+        # Sort by block counts, then by usable size.
+        return cmp(abs(r1.numBlocks), abs(r2.numBlocks)) or \
+               Record.cmpByUsableSize(r1, r2)
+
+
+sortByChoices = {
+    'usable':     Record.cmpByUsableSize,   # the default
+    'req':        Record.cmpByReqSize,
+    'slop':       Record.cmpBySlopSize,
+    'num-blocks': Record.cmpByNumBlocks,
+}
+
+
+def parseCommandLine():
+    # 24 is the maximum number of frames that DMD will produce.
+    def range_1_24(string):
+        value = int(string)
+        if value < 1 or value > 24:
+            msg = '{:s} is not in the range 1..24'.format(string)
+            raise argparse.ArgumentTypeError(msg)
+        return value
+
+    description = '''
+Analyze heap data produced by DMD.
+If one file is specified, analyze it; if two files are specified, analyze the
+difference.
+Input files can be gzipped.
+Write to stdout unless -o/--output is specified.
+Stack traces are fixed to show function names, filenames and line numbers
+unless --no-fix-stacks is specified; stack fixing modifies the original file
+and may take some time. If specified, the BREAKPAD_SYMBOLS_PATH environment
+variable is used to find breakpad symbols for stack fixing.
+'''
+    p = argparse.ArgumentParser(description=description)
+
+    p.add_argument('-o', '--output', type=argparse.FileType('w'),
+                   help='output file; stdout if unspecified')
+
+    p.add_argument('-f', '--max-frames', type=range_1_24,
+                   help='maximum number of frames to consider in each trace')
+
+    p.add_argument('-s', '--sort-by', choices=sortByChoices.keys(),
+                   default='usable',
+                   help='sort the records by a particular metric')
+
+    p.add_argument('-a', '--ignore-alloc-fns', action='store_true',
+                   help='ignore allocation functions at the start of traces')
+
+    p.add_argument('--no-fix-stacks', action='store_true',
+                   help='do not fix stacks')
+
+    p.add_argument('--clamp-contents', action='store_true',
+                   help='for a scan mode log, clamp addresses to the start of live blocks, or zero if not in one')
+
+    p.add_argument('--print-clamp-stats', action='store_true',
+                   help='print information about the results of pointer clamping; mostly useful for debugging clamping')
+
+    p.add_argument('--filter-stacks-for-testing', action='store_true',
+                   help='filter stack traces; only useful for testing purposes')
+
+    p.add_argument('input_file',
+                   help='a file produced by DMD')
+
+    p.add_argument('input_file2', nargs='?',
+                   help='a file produced by DMD; if present, it is diff\'d with input_file')
+
+    return p.parse_args(sys.argv[1:])
+
+
+# Fix stacks if necessary: first write the output to a tempfile, then replace
+# the original file with it.
+def fixStackTraces(inputFilename, isZipped, opener):
+    # This append() call is needed to make the import statements work when this
+    # script is installed as a symlink.
+    sys.path.append(os.path.dirname(__file__))
+
+    bpsyms = os.environ.get('BREAKPAD_SYMBOLS_PATH', None)
+    sysname = platform.system()
+    if bpsyms and os.path.exists(bpsyms):
+        import fix_stack_using_bpsyms as fixModule
+        fix = lambda line: fixModule.fixSymbols(line, bpsyms)
+    elif sysname == 'Linux':
+        import fix_linux_stack as fixModule
+        fix = lambda line: fixModule.fixSymbols(line)
+    elif sysname == 'Darwin':
+        import fix_macosx_stack as fixModule
+        fix = lambda line: fixModule.fixSymbols(line)
+    else:
+        fix = None  # there is no fix script for Windows
+
+    if fix:
+        # Fix stacks, writing output to a temporary file, and then
+        # overwrite the original file.
+        tmpFile = tempfile.NamedTemporaryFile(delete=False)
+
+        # If the input is gzipped, then the output (written initially to
+        # |tmpFile|) should be gzipped as well.
+        #
+        # And we want to set its pre-gzipped filename to '' rather than the
+        # name of the temporary file, so that programs like the Unix 'file'
+        # utility don't say that it was called 'tmp6ozTxE' (or something like
+        # that) before it was zipped. So that explains the |filename=''|
+        # parameter.
+        #
+        # But setting the filename like that clobbers |tmpFile.name|, so we
+        # must get that now in order to move |tmpFile| at the end.
+        tmpFilename = tmpFile.name
+        if isZipped:
+            tmpFile = gzip.GzipFile(filename='', fileobj=tmpFile)
+
+        with opener(inputFilename, 'rb') as inputFile:
+            for line in inputFile:
+                tmpFile.write(fix(line))
+
+        tmpFile.close()
+
+        shutil.move(tmpFilename, inputFilename)
+
+
+def getDigestFromFile(args, inputFile):
+    # Handle gzipped input if necessary.
+    isZipped = inputFile.endswith('.gz')
+    opener = gzip.open if isZipped else open
+
+    # Fix stack traces unless otherwise instructed.
+    if not args.no_fix_stacks:
+        fixStackTraces(inputFile, isZipped, opener)
+
+    if args.clamp_contents:
+        clampBlockList(args, inputFile, isZipped, opener)
+
+    with opener(inputFile, 'rb') as f:
+        j = json.load(f)
+
+    if j['version'] != outputVersion:
+        raise Exception("'version' property isn't '{:d}'".format(outputVersion))
+
+    # Extract the main parts of the JSON object.
+    invocation = j['invocation']
+    dmdEnvVar = invocation['dmdEnvVar']
+    mode = invocation['mode']
+    blockList = j['blockList']
+    traceTable = j['traceTable']
+    frameTable = j['frameTable']
+
+    # Insert the necessary entries for unrecorded stack traces. Note that 'ut'
+    # and 'uf' will not overlap with any keys produced by DMD's
+    # ToIdStringConverter::Base32() function.
+    unrecordedTraceID = 'ut'
+    unrecordedFrameID = 'uf'
+    traceTable[unrecordedTraceID] = [unrecordedFrameID]
+    frameTable[unrecordedFrameID] = \
+        '#00: (no stack trace recorded due to --stacks=partial)'
+
+    # For the purposes of this script, 'scan' behaves like 'live'.
+    if mode == 'scan':
+        mode = 'live'
+
+    if not mode in ['live', 'dark-matter', 'cumulative']:
+        raise Exception("bad 'mode' property: '{:s}'".format(mode))
+
+    # Remove allocation functions at the start of traces.
+    if args.ignore_alloc_fns:
+        # Build a regexp that matches every function in allocatorFns.
+        escapedAllocatorFns = map(re.escape, allocatorFns)
+        fn_re = re.compile('|'.join(escapedAllocatorFns))
+
+        # Remove allocator fns from each stack trace.
+        for traceKey, frameKeys in traceTable.items():
+            numSkippedFrames = 0
+            for frameKey in frameKeys:
+                frameDesc = frameTable[frameKey]
+                if re.search(fn_re, frameDesc):
+                    numSkippedFrames += 1
+                else:
+                    break
+            if numSkippedFrames > 0:
+                traceTable[traceKey] = frameKeys[numSkippedFrames:]
+
+    # Trim the number of frames.
+    for traceKey, frameKeys in traceTable.items():
+        if len(frameKeys) > args.max_frames:
+            traceTable[traceKey] = frameKeys[:args.max_frames]
+
+    def buildTraceDescription(traceTable, frameTable, traceKey):
+        frameKeys = traceTable[traceKey]
+        fmt = '    #{:02d}{:}'
+
+        if args.filter_stacks_for_testing:
+            # When running SmokeDMD.cpp, every stack trace should contain at
+            # least one frame that contains 'DMD.cpp', from either |DMD.cpp| or
+            # |SmokeDMD.cpp|. (Or 'dmd.cpp' on Windows.) If we see such a
+            # frame, we replace the entire stack trace with a single,
+            # predictable frame. There is too much variation in the stack
+            # traces across different machines and platforms to do more precise
+            # matching, but this level of matching will result in failure if
+            # stack fixing fails completely.
+            for frameKey in frameKeys:
+                frameDesc = frameTable[frameKey]
+                if 'DMD.cpp' in frameDesc or 'dmd.cpp' in frameDesc:
+                    return [fmt.format(1, ': ... DMD.cpp ...')]
+
+        # The frame number is always '#00' (see DMD.h for why), so we have to
+        # replace that with the correct frame number.
+        desc = []
+        for n, frameKey in enumerate(traceTable[traceKey], start=1):
+            desc.append(fmt.format(n, frameTable[frameKey][3:]))
+        return desc
+
+    # Aggregate blocks into records. All sufficiently similar blocks go into a
+    # single record.
+
+    if mode in ['live', 'cumulative']:
+        liveOrCumulativeRecords = collections.defaultdict(Record)
+    elif mode == 'dark-matter':
+        unreportedRecords    = collections.defaultdict(Record)
+        onceReportedRecords  = collections.defaultdict(Record)
+        twiceReportedRecords = collections.defaultdict(Record)
+
+    heapUsableSize = 0
+    heapBlocks = 0
+
+    recordKeyPartCache = {}
+
+    for block in blockList:
+        # For each block we compute a |recordKey|, and all blocks with the same
+        # |recordKey| are aggregated into a single record. The |recordKey| is
+        # derived from the block's 'alloc' and 'reps' (if present) stack
+        # traces.
+        #
+        # We use frame descriptions (e.g. "#00: foo (X.cpp:99)") when comparing
+        # traces for equality. We can't use trace keys or frame keys because
+        # they're not comparable across different DMD runs (which is relevant
+        # when doing diffs).
+        #
+        # Using frame descriptions also fits in with the stack trimming done
+        # for --max-frames, which requires that stack traces with common
+        # beginnings but different endings to be considered equivalent. E.g. if
+        # we have distinct traces T1:[A:D1,B:D2,C:D3] and T2:[X:D1,Y:D2,Z:D4]
+        # and we trim the final frame of each they should be considered
+        # equivalent because the untrimmed frame descriptions (D1 and D2)
+        # match.
+        #
+        # Having said all that, during a single invocation of dmd.py on a
+        # single DMD file, for a single frameKey value the record key will
+        # always be the same, and we might encounter it 1000s of times. So we
+        # cache prior results for speed.
+        def makeRecordKeyPart(traceKey):
+            if traceKey in recordKeyPartCache:
+                return recordKeyPartCache[traceKey]
+
+            recordKeyPart = str(map(lambda frameKey: frameTable[frameKey],
+                                    traceTable[traceKey]))
+            recordKeyPartCache[traceKey] = recordKeyPart
+            return recordKeyPart
+
+        allocatedAtTraceKey = block.get('alloc', unrecordedTraceID)
+        if mode in ['live', 'cumulative']:
+            recordKey = makeRecordKeyPart(allocatedAtTraceKey)
+            records = liveOrCumulativeRecords
+        elif mode == 'dark-matter':
+            recordKey = makeRecordKeyPart(allocatedAtTraceKey)
+            if 'reps' in block:
+                reportedAtTraceKeys = block['reps']
+                for reportedAtTraceKey in reportedAtTraceKeys:
+                    recordKey += makeRecordKeyPart(reportedAtTraceKey)
+                if len(reportedAtTraceKeys) == 1:
+                    records = onceReportedRecords
+                else:
+                    records = twiceReportedRecords
+            else:
+                records = unreportedRecords
+
+        record = records[recordKey]
+
+        if 'req' not in block:
+            raise Exception("'req' property missing in block'")
+
+        reqSize = block['req']
+        slopSize = block.get('slop', 0)
+
+        if 'num' in block:
+            num = block['num']
+        else:
+            num = 1
+
+        usableSize = reqSize + slopSize
+        heapUsableSize += num * usableSize
+        heapBlocks += num
+
+        record.numBlocks  += num
+        record.reqSize    += num * reqSize
+        record.slopSize   += num * slopSize
+        record.usableSize += num * usableSize
+        if record.allocatedAtDesc == None:
+            record.allocatedAtDesc = \
+                buildTraceDescription(traceTable, frameTable,
+                                      allocatedAtTraceKey)
+
+        if mode in ['live', 'cumulative']:
+            pass
+        elif mode == 'dark-matter':
+            if 'reps' in block and record.reportedAtDescs == []:
+                f = lambda k: buildTraceDescription(traceTable, frameTable, k)
+                record.reportedAtDescs = map(f, reportedAtTraceKeys)
+        record.usableSizes[usableSize] += num
+
+    # All the processed data for a single DMD file is called a "digest".
+    digest = {}
+    digest['dmdEnvVar'] = dmdEnvVar
+    digest['mode'] = mode
+    digest['heapUsableSize'] = heapUsableSize
+    digest['heapBlocks'] = heapBlocks
+    if mode in ['live', 'cumulative']:
+        digest['liveOrCumulativeRecords'] = liveOrCumulativeRecords
+    elif mode == 'dark-matter':
+        digest['unreportedRecords'] = unreportedRecords
+        digest['onceReportedRecords'] = onceReportedRecords
+        digest['twiceReportedRecords'] = twiceReportedRecords
+    return digest
+
+
+def diffRecords(args, records1, records2):
+    records3 = {}
+
+    # Process records1.
+    for k in records1:
+        r1 = records1[k]
+        if k in records2:
+            # This record is present in both records1 and records2.
+            r2 = records2[k]
+            del records2[k]
+            r2.subtract(r1)
+            if not r2.isZero(args):
+                records3[k] = r2
+        else:
+            # This record is present only in records1.
+            r1.negate()
+            records3[k] = r1
+
+    for k in records2:
+        # This record is present only in records2.
+        records3[k] = records2[k]
+
+    return records3
+
+
+def diffDigests(args, d1, d2):
+    if (d1['mode'] != d2['mode']):
+        raise Exception("the input files have different 'mode' properties")
+
+    d3 = {}
+    d3['dmdEnvVar'] = (d1['dmdEnvVar'], d2['dmdEnvVar'])
+    d3['mode'] = d1['mode']
+    d3['heapUsableSize'] = d2['heapUsableSize'] - d1['heapUsableSize']
+    d3['heapBlocks']     = d2['heapBlocks']     - d1['heapBlocks']
+    if d1['mode'] in ['live', 'cumulative']:
+        d3['liveOrCumulativeRecords'] = \
+            diffRecords(args, d1['liveOrCumulativeRecords'],
+                              d2['liveOrCumulativeRecords'])
+    elif d1['mode'] == 'dark-matter':
+        d3['unreportedRecords']    = diffRecords(args, d1['unreportedRecords'],
+                                                       d2['unreportedRecords'])
+        d3['onceReportedRecords']  = diffRecords(args, d1['onceReportedRecords'],
+                                                       d2['onceReportedRecords'])
+        d3['twiceReportedRecords'] = diffRecords(args, d1['twiceReportedRecords'],
+                                                       d2['twiceReportedRecords'])
+    return d3
+
+
+def printDigest(args, digest):
+    dmdEnvVar       = digest['dmdEnvVar']
+    mode            = digest['mode']
+    heapUsableSize  = digest['heapUsableSize']
+    heapBlocks      = digest['heapBlocks']
+    if mode in ['live', 'cumulative']:
+        liveOrCumulativeRecords = digest['liveOrCumulativeRecords']
+    elif mode == 'dark-matter':
+        unreportedRecords    = digest['unreportedRecords']
+        onceReportedRecords  = digest['onceReportedRecords']
+        twiceReportedRecords = digest['twiceReportedRecords']
+
+    separator = '#' + '-' * 65 + '\n'
+
+    def number(n):
+        '''Format a number with comma as a separator.'''
+        return '{:,d}'.format(n)
+
+    def perc(m, n):
+        return 0 if n == 0 else (100 * m / n)
+
+    def plural(n):
+        return '' if n == 1 else 's'
+
+    # Prints to stdout, or to file if -o/--output was specified.
+    def out(*arguments, **kwargs):
+        print(*arguments, file=args.output, **kwargs)
+
+    def printStack(traceDesc):
+        for frameDesc in traceDesc:
+            out(frameDesc)
+
+    def printRecords(recordKind, records, heapUsableSize):
+        RecordKind = recordKind.capitalize()
+        out(separator)
+        numRecords = len(records)
+        cmpRecords = sortByChoices[args.sort_by]
+        sortedRecords = sorted(records.values(), cmp=cmpRecords, reverse=True)
+        kindBlocks = 0
+        kindUsableSize = 0
+        maxRecord = 1000
+
+        # First iteration: get totals, etc.
+        for record in sortedRecords:
+            kindBlocks     += record.numBlocks
+            kindUsableSize += record.usableSize
+
+        # Second iteration: print.
+        if numRecords == 0:
+            out('# no {:} heap blocks\n'.format(recordKind))
+
+        kindCumulativeUsableSize = 0
+        for i, record in enumerate(sortedRecords, start=1):
+            # Stop printing at the |maxRecord|th record.
+            if i == maxRecord:
+                out('# {:}: stopping after {:,d} heap block records\n'.
+                    format(RecordKind, i))
+                break
+
+            kindCumulativeUsableSize += record.usableSize
+
+            out(RecordKind + ' {')
+            out('  {:} block{:} in heap block record {:,d} of {:,d}'.
+                format(number(record.numBlocks),
+                       plural(record.numBlocks), i, numRecords))
+            out('  {:} bytes ({:} requested / {:} slop)'.
+                format(number(record.usableSize),
+                       number(record.reqSize),
+                       number(record.slopSize)))
+
+            abscmp = lambda (usableSize1, _1), (usableSize2, _2): \
+                            cmp(abs(usableSize1), abs(usableSize2))
+            usableSizes = sorted(record.usableSizes.items(), cmp=abscmp,
+                                 reverse=True)
+
+            hasSingleBlock = len(usableSizes) == 1 and usableSizes[0][1] == 1
+
+            if not hasSingleBlock:
+                out('  Individual block sizes: ', end='')
+                if len(usableSizes) == 0:
+                    out('(no change)', end='')
+                else:
+                    isFirst = True
+                    for usableSize, count in usableSizes:
+                        if not isFirst:
+                            out('; ', end='')
+                        out('{:}'.format(number(usableSize)), end='')
+                        if count > 1:
+                            out(' x {:,d}'.format(count), end='')
+                        isFirst = False
+                out()
+
+            out('  {:4.2f}% of the heap ({:4.2f}% cumulative)'.
+                format(perc(record.usableSize, heapUsableSize),
+                       perc(kindCumulativeUsableSize, heapUsableSize)))
+            if mode in ['live', 'cumulative']:
+                pass
+            elif mode == 'dark-matter':
+                out('  {:4.2f}% of {:} ({:4.2f}% cumulative)'.
+                    format(perc(record.usableSize, kindUsableSize),
+                           recordKind,
+                           perc(kindCumulativeUsableSize, kindUsableSize)))
+            out('  Allocated at {')
+            printStack(record.allocatedAtDesc)
+            out('  }')
+            if mode in ['live', 'cumulative']:
+                pass
+            elif mode == 'dark-matter':
+                for n, reportedAtDesc in enumerate(record.reportedAtDescs):
+                    again = 'again ' if n > 0 else ''
+                    out('  Reported {:}at {{'.format(again))
+                    printStack(reportedAtDesc)
+                    out('  }')
+            out('}\n')
+
+        return (kindUsableSize, kindBlocks)
+
+
+    def printInvocation(n, dmdEnvVar, mode):
+        out('Invocation{:} {{'.format(n))
+        if dmdEnvVar == None:
+            out('  $DMD is undefined')
+        else:
+            out('  $DMD = \'' + dmdEnvVar + '\'')
+        out('  Mode = \'' + mode + '\'')
+        out('}\n')
+
+    # Print command line. Strip dirs so the output is deterministic, which is
+    # needed for testing.
+    out(separator, end='')
+    out('# ' + ' '.join(map(os.path.basename, sys.argv)) + '\n')
+
+    # Print invocation(s).
+    if type(dmdEnvVar) is not tuple:
+        printInvocation('', dmdEnvVar, mode)
+    else:
+        printInvocation(' 1', dmdEnvVar[0], mode)
+        printInvocation(' 2', dmdEnvVar[1], mode)
+
+    # Print records.
+    if mode in ['live', 'cumulative']:
+        liveOrCumulativeUsableSize, liveOrCumulativeBlocks = \
+            printRecords(mode, liveOrCumulativeRecords, heapUsableSize)
+    elif mode == 'dark-matter':
+        twiceReportedUsableSize, twiceReportedBlocks = \
+            printRecords('twice-reported', twiceReportedRecords, heapUsableSize)
+
+        unreportedUsableSize, unreportedBlocks = \
+            printRecords('unreported', unreportedRecords, heapUsableSize)
+
+        onceReportedUsableSize, onceReportedBlocks = \
+            printRecords('once-reported', onceReportedRecords, heapUsableSize)
+
+    # Print summary.
+    out(separator)
+    out('Summary {')
+    if mode in ['live', 'cumulative']:
+        out('  Total: {:} bytes in {:} blocks'.
+            format(number(liveOrCumulativeUsableSize),
+                   number(liveOrCumulativeBlocks)))
+    elif mode == 'dark-matter':
+        fmt = '  {:15} {:>12} bytes ({:6.2f}%) in {:>7} blocks ({:6.2f}%)'
+        out(fmt.
+            format('Total:',
+                   number(heapUsableSize),
+                   100,
+                   number(heapBlocks),
+                   100))
+        out(fmt.
+            format('Unreported:',
+                   number(unreportedUsableSize),
+                   perc(unreportedUsableSize, heapUsableSize),
+                   number(unreportedBlocks),
+                   perc(unreportedBlocks, heapBlocks)))
+        out(fmt.
+            format('Once-reported:',
+                   number(onceReportedUsableSize),
+                   perc(onceReportedUsableSize, heapUsableSize),
+                   number(onceReportedBlocks),
+                   perc(onceReportedBlocks, heapBlocks)))
+        out(fmt.
+            format('Twice-reported:',
+                   number(twiceReportedUsableSize),
+                   perc(twiceReportedUsableSize, heapUsableSize),
+                   number(twiceReportedBlocks),
+                   perc(twiceReportedBlocks, heapBlocks)))
+    out('}\n')
+
+
+#############################
+# Pretty printer for DMD JSON
+#############################
+
+def prettyPrintDmdJson(out, j):
+    out.write('{\n')
+
+    out.write(' "version": {0},\n'.format(j['version']))
+    out.write(' "invocation": ')
+    json.dump(j['invocation'], out, sort_keys=True)
+    out.write(',\n')
+
+    out.write(' "blockList": [')
+    first = True
+    for b in j['blockList']:
+        out.write('' if first else ',')
+        out.write('\n  ')
+        json.dump(b, out, sort_keys=True)
+        first = False
+    out.write('\n ],\n')
+
+    out.write(' "traceTable": {')
+    first = True
+    for k, l in j['traceTable'].iteritems():
+        out.write('' if first else ',')
+        out.write('\n  "{0}": {1}'.format(k, json.dumps(l)))
+        first = False
+    out.write('\n },\n')
+
+    out.write(' "frameTable": {')
+    first = True
+    for k, v in j['frameTable'].iteritems():
+        out.write('' if first else ',')
+        out.write('\n  "{0}": {1}'.format(k, json.dumps(v)))
+        first = False
+    out.write('\n }\n')
+
+    out.write('}\n')
+
+
+##################################################################
+# Code for clamping addresses using conservative pointer analysis.
+##################################################################
+
+# Start is the address of the first byte of the block, while end is
+# the address of the first byte after the final byte in the block.
+class AddrRange:
+    def __init__(self, block, length):
+        self.block = block
+        self.start = int(block, 16)
+        self.length = length
+        self.end = self.start + self.length
+
+        assert self.start > 0
+        assert length >= 0
+
+
+class ClampStats:
+    def __init__(self):
+        # Number of pointers already pointing to the start of a block.
+        self.startBlockPtr = 0
+
+        # Number of pointers pointing to the middle of a block. These
+        # are clamped to the start of the block they point into.
+        self.midBlockPtr = 0
+
+        # Number of null pointers.
+        self.nullPtr = 0
+
+        # Number of non-null pointers that didn't point into the middle
+        # of any blocks. These are clamped to null.
+        self.nonNullNonBlockPtr = 0
+
+
+    def clampedBlockAddr(self, sameAddress):
+        if sameAddress:
+            self.startBlockPtr += 1
+        else:
+            self.midBlockPtr += 1
+
+    def nullAddr(self):
+        self.nullPtr += 1
+
+    def clampedNonBlockAddr(self):
+        self.nonNullNonBlockPtr += 1
+
+    def log(self):
+        sys.stderr.write('Results:\n')
+        sys.stderr.write('  Number of pointers already pointing to start of blocks: ' + str(self.startBlockPtr) + '\n')
+        sys.stderr.write('  Number of pointers clamped to start of blocks: ' + str(self.midBlockPtr) + '\n')
+        sys.stderr.write('  Number of non-null pointers not pointing into blocks clamped to null: ' + str(self.nonNullNonBlockPtr) + '\n')
+        sys.stderr.write('  Number of null pointers: ' + str(self.nullPtr) + '\n')
+
+
+# Search the block ranges array for a block that address points into.
+# The search is carried out in an array of starting addresses for each blocks
+# because it is faster.
+def clampAddress(blockRanges, blockStarts, clampStats, address):
+    i = bisect_right(blockStarts, address)
+
+    # Any addresses completely out of the range should have been eliminated already.
+    assert i > 0
+    r = blockRanges[i - 1]
+    assert r.start <= address
+
+    if address >= r.end:
+        assert address < blockRanges[i].start
+        clampStats.clampedNonBlockAddr()
+        return '0'
+
+    clampStats.clampedBlockAddr(r.start == address)
+    return r.block
+
+
+def clampBlockList(args, inputFileName, isZipped, opener):
+    # XXX This isn't very efficient because we end up reading and writing
+    # the file multiple times.
+    with opener(inputFileName, 'rb') as f:
+        j = json.load(f)
+
+    if j['version'] != outputVersion:
+        raise Exception("'version' property isn't '{:d}'".format(outputVersion))
+
+    # Check that the invocation is reasonable for contents clamping.
+    invocation = j['invocation']
+    if invocation['mode'] != 'scan':
+        raise Exception("Log was taken in mode " + invocation['mode'] + " not scan")
+
+    sys.stderr.write('Creating block range list.\n')
+    blockList = j['blockList']
+    blockRanges = []
+    for block in blockList:
+        blockRanges.append(AddrRange(block['addr'], block['req']))
+    blockRanges.sort(key=lambda r: r.start)
+
+    # Make sure there are no overlapping blocks.
+    prevRange = blockRanges[0]
+    for currRange in blockRanges[1:]:
+        assert prevRange.end <= currRange.start
+        prevRange = currRange
+
+    sys.stderr.write('Clamping block contents.\n')
+    clampStats = ClampStats()
+    firstAddr = blockRanges[0].start
+    lastAddr = blockRanges[-1].end
+
+    blockStarts = []
+    for r in blockRanges:
+        blockStarts.append(r.start)
+
+    for block in blockList:
+        # Small blocks don't have any contents.
+        if not 'contents' in block:
+            continue
+
+        cont = block['contents']
+        for i in range(len(cont)):
+            address = int(cont[i], 16)
+
+            if address == 0:
+                clampStats.nullAddr()
+                continue
+
+            # If the address is before the first block or after the last
+            # block then it can't be within a block.
+            if address < firstAddr or address >= lastAddr:
+                clampStats.clampedNonBlockAddr()
+                cont[i] = '0'
+                continue
+
+            cont[i] = clampAddress(blockRanges, blockStarts, clampStats, address)
+
+        # Remove any trailing nulls.
+        while len(cont) and cont[-1] == '0':
+            cont.pop()
+
+    if args.print_clamp_stats:
+        clampStats.log()
+
+    sys.stderr.write('Saving file.\n')
+    tmpFile = tempfile.NamedTemporaryFile(delete=False)
+    tmpFilename = tmpFile.name
+    if isZipped:
+        tmpFile = gzip.GzipFile(filename='', fileobj=tmpFile)
+    prettyPrintDmdJson(tmpFile, j)
+    tmpFile.close()
+    shutil.move(tmpFilename, inputFileName)
+
+
+def main():
+    args = parseCommandLine()
+    digest = getDigestFromFile(args, args.input_file)
+    if args.input_file2:
+        digest2 = getDigestFromFile(args, args.input_file2)
+        digest = diffDigests(args, digest, digest2)
+    printDigest(args, digest)
+
+
+if __name__ == '__main__':
+    main()
+