tools: add performance-log-coalesce.py; use in performance-log-viewer

Add a new performance-log-coalesce.py tool, which groups together
performance-log address-map entries belonging to the same function
into a single symbol, by filling-in missing base symbol addresses.
The addresses are grouped such that each set of addresses
corresponding to a symbol of the same name, in the same source
file, are given the same (unique, but arbitrary) base address.
See the previous commit for why this is necessary.

This should work fine in most cases, however, for logs produced on
Windows, it can over-coalesce addresses belonging to different C++
lambda-functions in the same source file, since they all seem to be
given the same _FUN symbol name.

Use the new tool as part of the pipeline in performance-log-viewer.

tools/performance-log-coalesce.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+
+"""
+performance-log-coalesce.py -- Coalesce GIMP performance log symbols, by
+                               filling-in missing base addresses
+Copyright (C) 2018  Ell
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+
+Usage: performance-log-coalesce.py < infile > outfile
+"""
+
+from xml.etree import ElementTree
+import sys
+
+empty_element = ElementTree.Element ("")
+
+# Read performance log from STDIN
+log = ElementTree.fromstring (sys.stdin.buffer.read ())
+
+address_map = log.find ("address-map")
+
+if address_map:
+    addresses = []
+
+    # Create base addresses dictionary
+    base_addresses = {}
+
+    for address in address_map.iterfind ("address"):
+        symbol = address.find ("symbol").text
+        source = address.find ("source").text
+        base   = address.find ("base").text
+
+        if symbol and source and not base:
+            key   = (symbol, source)
+            value = int (address.get ("value"), 0)
+
+            base_addresses[key] = min (value, base_addresses.get (key, value))
+
+            addresses.append (address)
+
+    # Fill-in missing base addresses
+    for address in addresses:
+        symbol = address.find ("symbol").text
+        source = address.find ("source").text
+
+        address.find ("base").text = hex (base_addresses[(symbol, source)])
+
+# Write performance log to STDOUT
+sys.stdout.buffer.write (ElementTree.tostring (log))

tools/performance-log-viewer

@@ -32,5 +32,6 @@ file="$1"
 
 < "$file"                                  \
 "$tools_dir/performance-log-expand.py"   | \
+"$tools_dir/performance-log-coalesce.py" | \
 "$tools_dir/performance-log-deduce.py"   | \
 "$tools_dir/performance-log-viewer.py"