* A stdenv adapter to build a package with coverage instrumentation.

svn path=/nixpkgs/trunk/; revision=16890

1 files changed, 50 insertions, 0 deletions

diff --git a/pkgs/stdenv/adapters.nix b/pkgs/stdenv/adapters.nix
index 2cdf95476a5..621aef466aa 100644
--- a/pkgs/stdenv/adapters.nix
+++ b/pkgs/stdenv/adapters.nix
@@ -121,4 +121,54 @@ rec {
     { mkDerivation = args: stdenv.mkDerivation (args // extraAttrs); };
 
 
+  /* Return a modified stdenv that builds packages with GCC's coverage
+     instrumentation.  The coverage note files (*.gcno) are stored in
+     $out/.coverage, along with the source code of the package, to
+     enable programs like lcov to produce pretty-printed reports.
+  */
+  addCoverageInstrumentation = stdenv:
+    addAttrsToDerivation
+      { NIX_CFLAGS_COMPILE = "-O0 --coverage";
+
+        prePhases = "moveBuildDir";
+        postPhases = "cleanupBuildDir";
+
+        # Object files instrumented with coverage analysis write
+        # runtime coverage data to <path>/<object>.gcda, where <path>
+        # is the location where gcc originally created the object
+        # file.  That would be /tmp/nix-build-<something>, which will
+        # be long gone by the time we run the program.  Furthermore,
+        # the <object>.gcno files created at compile time are also
+        # written there.  And to make nice coverage reports with lcov,
+        # we need the source code.  So we move the whole build tree to
+        # $out/.coverage.
+        moveBuildDir =
+          ''
+            ensureDir $out/.coverage
+            cd $out/.coverage
+          '';
+
+        # This is an uberhack to prevent libtool from removing gcno
+        # files.  This has been fixed in libtool, but there are
+        # packages out there with old ltmain.sh scripts.
+        # See http://www.mail-archive.com/libtool@gnu.org/msg10725.html
+        postUnpack =
+          ''
+            for i in $(find -name ltmain.sh); do
+                substituteInPlace $i --replace '*.$objext)' '*.$objext | *.gcno)'
+            done
+          '';
+
+        # Get rid of everything that isn't a gcno file or a C source
+        # file.  This also includes the gcda files; we're not
+        # interested in coverage resulting from the package's own test
+        # suite.
+        cleanupBuildDir =
+          ''
+             find $out/.coverage/ -type f -a ! \
+               \( -name "*.c" -o -name "*.gcno" -o -name "*.h" \) \
+               | xargs rm -f --
+          '';
+      }
+      stdenv;
 }