Add support for PERF_RECORD_MMAP2 record type

Newer perf.data contains both MMAP and MMAP2 record type,
but MMAP2 record type is not supported in previous ll_prof,
MMAP2 record information will be lost.

BUG=v8:4569
LOG=n

Review URL: https://codereview.chromium.org/1469153004

Cr-Commit-Position: refs/heads/master@{#32319}

tools/ll_prof.py

@@ -568,7 +568,7 @@ PERF_EVENT_HEADER_DESC = Descriptor([
 ])
 
 
-# Reference: kernel/events/core.c
+# Reference: kernel/tools/perf/util/event.h
 PERF_MMAP_EVENT_BODY_DESC = Descriptor([
   ("pid", "u32"),
   ("tid", "u32"),
@@ -577,6 +577,20 @@ PERF_MMAP_EVENT_BODY_DESC = Descriptor([
   ("pgoff", "u64")
 ])
 
+# Reference: kernel/tools/perf/util/event.h
+PERF_MMAP2_EVENT_BODY_DESC = Descriptor([
+  ("pid", "u32"),
+  ("tid", "u32"),
+  ("addr", "u64"),
+  ("len", "u64"),
+  ("pgoff", "u64"),
+  ("maj", "u32"),
+  ("min", "u32"),
+  ("ino", "u64"),
+  ("ino_generation", "u64"),
+  ("prot", "u32"),
+  ("flags","u32")
+])
 
 # perf_event_attr.sample_type bits control the set of
 # perf_sample_event fields.
@@ -616,6 +630,7 @@ PERF_SAMPLE_EVENT_IP_FORMAT = "u64"
 
 
 PERF_RECORD_MMAP = 1
+PERF_RECORD_MMAP2 = 10
 PERF_RECORD_SAMPLE = 9
 
 
@@ -664,6 +679,15 @@ class TraceReader(object):
     mmap_info.filename = HOST_ROOT + filename[:filename.find(chr(0))]
     return mmap_info
 
+  def ReadMmap2(self, header, offset):
+    mmap_info = PERF_MMAP2_EVENT_BODY_DESC.Read(self.trace,
+                                                offset + self.header_size)
+    # Read null-terminated filename.
+    filename = self.trace[offset + self.header_size + ctypes.sizeof(mmap_info):
+                          offset + header.size]
+    mmap_info.filename = HOST_ROOT + filename[:filename.find(chr(0))]
+    return mmap_info
+
   def ReadSample(self, header, offset):
     sample = self.sample_event_body_desc.Read(self.trace,
                                               offset + self.header_size)
@@ -973,6 +997,14 @@ if __name__ == "__main__":
       else:
         library_repo.Load(mmap_info, code_map, options)
       mmap_time += time.time() - start
+    elif header.type == PERF_RECORD_MMAP2:
+      start = time.time()
+      mmap_info = trace_reader.ReadMmap2(header, offset)
+      if mmap_info.filename == HOST_ROOT + V8_GC_FAKE_MMAP:
+        log_reader.ReadUpToGC()
+      else:
+        library_repo.Load(mmap_info, code_map, options)
+      mmap_time += time.time() - start
     elif header.type == PERF_RECORD_SAMPLE:
       ticks += 1
       start = time.time()