Bug 1904685 - Output the addresses in dmd.py, when present. r=pbone

With heap scan mode, the DMD log includes the address of every block.
This patch includes the addresses in the output, if they are present.
This is useful when no cycle collected objects are leaked.

Differential Revision: https://phabricator.services.mozilla.com/D214880

memory/replace/dmd/dmd.py

@@ -71,6 +71,7 @@ class Record(object):
         self.allocatedAtDesc = None
         self.reportedAtDescs = []
         self.usableSizes = collections.defaultdict(int)
+        self.addrs = []
 
     def isZero(self, args):
         return (
@@ -504,6 +505,10 @@ def getDigestFromFile(args, inputFile):
                 traceTable, frameTable, allocatedAtTraceKey
             )
 
+        # In heap scan mode, we record the address of every block.
+        if "addr" in block:
+            record.addrs.append(block["addr"])
+
         if mode in ["live", "cumulative"]:
             pass
         elif mode == "dark-matter":
@@ -674,6 +679,14 @@ def printDigest(args, digest):
                     number(record.numBlocks), plural(record.numBlocks), i, numRecords
                 )
             )
+            if record.addrs:
+                if args.filter_stacks_for_testing:
+                    # These addresses will vary, so for testing replace them with a fixed value.
+                    baseAddrs = ["dadadada" for a in record.addrs]
+                else:
+                    baseAddrs = sorted(record.addrs)
+                addrsString = ", ".join([f"0x{a}" for a in baseAddrs])
+                out("  block addresses: " + addrsString)
             out(
                 "  {:} bytes ({:} requested / {:} slop)".format(
                     number(record.usableSize),

memory/replace/dmd/test/basic-scan-32-expected.txt

@@ -10,6 +10,7 @@ Invocation {
 
 Live {
   1 block in heap block record 1 of 1
+  block addresses: 0xdadadada
   32 bytes (24 requested / 8 slop)
   100.00% of the heap (100.00% cumulative)
   Allocated at {

memory/replace/dmd/test/basic-scan-64-expected.txt

@@ -10,6 +10,7 @@ Invocation {
 
 Live {
   1 block in heap block record 1 of 1
+  block addresses: 0xdadadada
   48 bytes (48 requested / 0 slop)
   100.00% of the heap (100.00% cumulative)
   Allocated at {