Coverage support: build with --enable-coverage to have tests run with gcov

If you pass the --enable-coverage flag on the command line, we build
our testing binaries with appropriate options eo enable coverage
testing.  We also build a "tor-cov" binary that has coverage enabled,
for integration tests.

On recent OSX versions, test coverage only works with clang, not gcc.
So we warn about that.

Also add a contrib/coverage script to actually run gcov with the
appropriate options to generate useful .gcov files.  (Thanks to
automake, the .o files will not have the names that gcov expects to
find.)

Also, remove generated gcda and gcno files on clean.

8 files changed, 61 insertions, 2 deletions

diff --git a/.gitignore b/.gitignore
index bb3817ba57..201d04da66 100644
--- a/.gitignore
+++ b/.gitignore
@@ -152,6 +152,8 @@
 /src/or/or_sha1.i
 /src/or/tor
 /src/or/tor.exe
+/src/or/tor-cov
+/src/or/tor-cov.exe
 /src/or/libtor.a
 /src/or/libtor-testing.a
 /src/or/libtor.lib
diff --git a/Makefile.am b/Makefile.am
index a736638e4b..1bc1077ebb 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -32,6 +32,12 @@ EXTRA_DIST+= \
 	README						\
 	ReleaseNotes
 
+if COVERAGE_ENABLED
+TEST_CFLAGS=-fno-inline -fprofile-arcs -ftest-coverage
+else
+TEST_CFLAGS=
+endif
+
 #install-data-local:
 #	$(INSTALL) -m 755 -d $(LOCALSTATEDIR)/lib/tor
 
@@ -89,3 +95,5 @@ version:
 	   (cd "$(top_srcdir)" && git rev-parse --short=16 HEAD); \
 	fi
 
+mostlyclean-local:
+	rm -f src/*/*.gc{da,no}
diff --git a/changes/fancy_testing b/changes/fancy_testing
index 3e8ccbca48..ad197c6f58 100644
--- a/changes/fancy_testing
+++ b/changes/fancy_testing
@@ -10,3 +10,7 @@
       in the unit tests; all functions exposed from a module for
       unit-testing only are now static in production builds.
 
+    - Add an --enable-coverage configuration option to make the unit
+      tests (and a new src/or/tor-cov target) to build with gcov test
+      coverage support.
+
diff --git a/configure.ac b/configure.ac
index 34ed524dd8..22aac31bf2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -41,8 +41,13 @@ AC_ARG_ENABLE(curve25519,
    AS_HELP_STRING(--disable-curve25519, Build Tor with no curve25519 elliptic-curve crypto support))
 AC_ARG_ENABLE(unittests,
    AS_HELP_STRING(--disable-unittests, [Don't build unit tests for Tor. Risky!]))
+AC_ARG_ENABLE(coverage,
+   AS_HELP_STRING(--enable-coverage, [Enable coverage support in the unit-test build]))
 
-AM_CONDITIONAL(UNITTESTS_ENABLED, test x$unittests != xno)
+AM_CONDITIONAL(UNITTESTS_ENABLED, test x$enable_unittests != xno)
+AM_CONDITIONAL(COVERAGE_ENABLED, test x$enable_coverage = xyes)
+
+echo "COVERAGE: $enable_coverage"
 
 if test "$enable_static_tor" = "yes"; then
   enable_static_libevent="yes";
@@ -1457,7 +1462,12 @@ if test x$enable_gcc_warnings = xyes || test x$enable_gcc_warnings_advisory = xy
 # CFLAGS="$CFLAGS -Winline"
 fi
 
-
+if test "$enable_coverage" = yes && test "$have_clang" = "no"; then
+   case "$host_os" in
+    darwin*)
+      AC_MSG_WARN([Tried to enable coverage on OSX without using the clang compiler. This might not work! If coverage fails, use CC=clang when configuring with --enable-profiling.])
+   esac
+fi
 
 CPPFLAGS="$CPPFLAGS $TOR_CPPFLAGS_libevent $TOR_CPPFLAGS_openssl $TOR_CPPFLAGS_zlib"
 
diff --git a/contrib/coverage b/contrib/coverage
new file mode 100755
index 0000000000..52fe96d756
--- /dev/null
+++ b/contrib/coverage
@@ -0,0 +1,13 @@
+#!/bin/sh
+# Copyright 2013  The Tor Project, Inc.
+# See LICENSE for licensing information.
+
+# coverage -- run gcov on the appropriate set of object files to extract
+# coverage information.
+
+for fn in src/{or,common}/*.c; do
+    BN=`basename $fn`
+    DN=`dirname $fn`
+    F=`echo $BN | sed -e 's/\.c$//;'`
+    gcov -o $DN/src_*$F.o $fn
+done
diff --git a/src/common/include.am b/src/common/include.am
index 3d8cc8e9eb..3f5a0e0d0e 100644
--- a/src/common/include.am
+++ b/src/common/include.am
@@ -82,6 +82,10 @@ src_common_libor_event_testing_a_SOURCES = $(LIBOR_EVENT_A_SOURCES)
 src_common_libor_testing_a_CPPFLAGS = -DTOR_UNIT_TESTS $(AM_CPPFLAGS)
 src_common_libor_crypto_testing_a_CPPFLAGS = -DTOR_UNIT_TESTS $(AM_CPPFLAGS)
 src_common_libor_event_testing_a_CPPFLAGS = -DTOR_UNIT_TESTS $(AM_CPPFLAGS)
+src_common_libor_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+src_common_libor_crypto_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+src_common_libor_event_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+
 
 COMMONHEADERS = \
   src/common/address.h				\
diff --git a/src/or/include.am b/src/or/include.am
index 91b9bfce72..f5002e6986 100644
--- a/src/or/include.am
+++ b/src/or/include.am
@@ -5,6 +5,9 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += \
 	src/or/libtor-testing.a
 endif
+if COVERAGE_ENABLED
+noinst_PROGRAMS+= src/or/tor-cov
+endif
 
 if BUILD_NT_SERVICES
 tor_platform_source=src/or/ntmain.c
@@ -99,6 +102,7 @@ AM_CPPFLAGS += -DSHARE_DATADIR="\"$(datadir)\"" \
         -DBINDIR="\"$(bindir)\""
 
 src_or_libtor_testing_a_CPPFLAGS = -DTOR_UNIT_TESTS $(AM_CPPFLAGS)
+src_or_libtor_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
 # -L flags need to go in LDFLAGS. -l flags need to go in LDADD.
 # This seems to matter nowhere but on windows, but I assure you that it
@@ -112,6 +116,18 @@ src_or_tor_LDADD = src/or/libtor.a src/common/libor.a \
 	@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@ @TOR_LIBEVENT_LIBS@ @TOR_OPENSSL_LIBS@ \
 	@TOR_LIB_WS32@ @TOR_LIB_GDI@ @CURVE25519_LIBS@
 
+if COVERAGE_ENABLED
+src_or_tor_cov_SOURCES = src/or/tor_main.c
+src_or_tor_cov_CPPFLAGS = -DTOR_UNIT_TESTS $(AM_CPPFLAGS)
+src_or_tor_cov_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+src_or_tor_cov_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ @TOR_LDFLAGS_libevent@
+src_or_tor_cov_LDADD = src/or/libtor-testing.a src/common/libor-testing.a \
+	src/common/libor-crypto-testing.a $(LIBDONNA) \
+	src/common/libor-event-testing.a \
+	@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@ @TOR_LIBEVENT_LIBS@ @TOR_OPENSSL_LIBS@ \
+	@TOR_LIB_WS32@ @TOR_LIB_GDI@ @CURVE25519_LIBS@
+endif
+
 ORHEADERS = \
 	src/or/addressmap.h				\
 	src/or/buffers.h				\
diff --git a/src/test/include.am b/src/test/include.am
index 08eb7fba67..989cf4ebfc 100644
--- a/src/test/include.am
+++ b/src/test/include.am
@@ -31,6 +31,8 @@ src_test_test_SOURCES = \
 	src/test/test_config.c \
 	src/ext/tinytest.c
 
+src_test_test_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+
 src_test_test_CPPFLAGS= $(src_test_AM_CPPFLAGS)
 
 src_test_bench_SOURCES = \