From 1eb210637539ce71794ff49fc462c35511b8a141 Mon Sep 17 00:00:00 2001
From: Nick Mathewson <nickm@torproject.org>
Date: Tue, 25 Aug 2015 11:53:20 -0400
Subject: [PATCH] Document callgraph analysis code
---
doc/HACKING | 17 +++++++++++++++++
scripts/maint/generate_callgraph.sh | 3 ++-
2 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/doc/HACKING b/doc/HACKING
index 7ee5cf846b..e92d675a43 100644
--- a/doc/HACKING
+++ b/doc/HACKING
@@ -265,6 +265,23 @@ Here are some basic instructions
* "opreport -l that_dir/*"
- Profit
+Generating and analyzing a callgraph
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+1. Run ./scripts/maint/generate_callgraph.sh . This will generate a
+ bunch of files in a new ./callgraph directory.
+
+2. Run ./scripts/maint/analyze_callgraph.py callgraph/src/*/* . This
+ will do a lot of graph operations and then dump out a new
+ "callgraph.pkl" file, containing data in Python's "pickle" format.
+
+3. Run ./scripts/maint/display_callgraph.py . It will display:
+ - the number of functions reachable from each function.
+ - all strongly-connnected components in the Tor callgraph
+ - the largest bottlenecks in the largest SCC in the Tor callgraph.
+
+Note that currently the callgraph generator can't detect calls that pass
+through function pointers.
Coding conventions
------------------
diff --git a/scripts/maint/generate_callgraph.sh b/scripts/maint/generate_callgraph.sh
index 97330cc949..c6b33c0aea 100755
--- a/scripts/maint/generate_callgraph.sh
+++ b/scripts/maint/generate_callgraph.sh
@@ -8,6 +8,7 @@ mkdir -p callgraph/src/or
mkdir -p callgraph/src/tools
for fn in $C_FILES; do
+ echo $fn
clang $CFLAGS -S -emit-llvm -fno-inline -o - $fn | \
- opt -analyze -print-callgraph 2> "callgraph/${fn}allgraph"
+ opt -analyze -print-callgraph >/dev/null 2> "callgraph/${fn}allgraph"
done
--
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