tcwg_kernel-bisect.sh: Handle bisecting between branches/tags

Rename bad_rev and baseline_rev to bad_branch and baseline_branch,
and resolve them to SHA1 revisions.

The motivation for this change is ability to gather historical data,
e.g., code size regressions from GCC/LLVM 5 to 6, to 7, to 8, and so on.

The bisects are intended to be triggered manually, which is why
branch handling is desired.

Change-Id: I9c46270e0092e72836986a4bed08799ec6d84a00

2 files changed, 20 insertions, 11 deletions

diff --git a/round-robin.sh b/round-robin.sh
index 5c665887..81b04e95 100644
--- a/round-robin.sh
+++ b/round-robin.sh
@@ -349,8 +349,8 @@ check_regression ()
 
 	    cat > ${rr[top_artifacts]}/trigger-bisect <<EOF
 current_project=$single_component
-baseline_rev=$baseline_rev
-bad_rev=$cur_rev
+baseline_branch=$baseline_rev
+bad_branch=$cur_rev
 EOF
 	fi
 
diff --git a/tcwg_kernel-bisect.sh b/tcwg_kernel-bisect.sh
index 7fb28b17..bfc8e6db 100755
--- a/tcwg_kernel-bisect.sh
+++ b/tcwg_kernel-bisect.sh
@@ -16,7 +16,7 @@ fresh_dir $artifacts "$artifacts/manifests/*" "$artifacts/jenkins/*"
 convert_args_to_variables "$@"
 shift "$SHIFT_CONVERTED_ARGS"
 
-obligatory_variables bad_rev baseline_rev build_script current_project
+obligatory_variables bad_branch baseline_branch build_script current_project
 
 BUILD_URL="${BUILD_URL:-$(pwd)}"
 reproduce_bisect="${reproduce_bisect:-false}"
@@ -43,7 +43,8 @@ case "${rr[ci_project]}/${rr[ci_config]}:$current_project" in
 	# Search for regressions against linux-mainline:master (aka linux-next:stable).
 	clone_or_update_repo $current_project stable ${rr[linux_url]}
 	# Just in case linux-next:stable has advanced between the build and bisect jobs,
-	# use merge base between linux-next:stable and $bad_rev.
+	# use merge base between linux-next:stable and $bad_branch.
+	bad_rev="${bad_rev-$(git_rev_parse_long $current_project $bad_branch)}"
 	linux_next_stable="${linux_next_stable-$(git -C $current_project merge-base HEAD $bad_rev)}"
 	cat <<EOF | manifest_out
 declare -g linux_next_stable=$linux_next_stable
@@ -56,20 +57,21 @@ esac
 
 # Build baseline that we are going to re-use to speed-up bisection.
 # (This also confirms that infrastructure is OK.)
-echo "Testing baseline_rev $baseline_rev (should be success)"
+echo "Testing baseline_branch $baseline_branch (should be success)"
 $build_script \
     ^^ $reproduce_bisect \
     %% $rel_artifacts/manifests/build-baseline.sh \
     @@ $rel_artifacts/manifests/build-parameters.sh \
     ==rr[mode] "baseline" \
-    ==rr[${current_project}_branch] "$baseline_rev" \
+    ==rr[${current_project}_branch] "$baseline_branch" \
     ==rr[reset_baseline] true \
     ==rr[top_artifacts] "$rel_artifacts/build-baseline" \
     --verbose "$verbose"
 
-assert ! [ -f $artifacts/failures ]
-
-cd $current_project
+baseline_rev="${baseline_rev-$(git -C ${current_project} rev-parse HEAD)}"
+cat <<EOF | manifest_out
+declare -g baseline_rev=$baseline_rev
+EOF
 
 ln -f -s "build-baseline" "$artifacts/build-$baseline_rev"
 ln -f -s "build-baseline.sh" "$artifacts/manifests/build-$baseline_rev.sh"
@@ -134,6 +136,13 @@ fi
 EOF
 chmod +x $artifacts/test.sh
 
+bad_rev="${bad_rev-$(git_rev_parse_long $current_project $bad_branch)}"
+cat <<EOF | manifest_out
+declare -g bad_rev=$bad_rev
+EOF
+
+cd $current_project
+
 git checkout --detach $bad_rev
 $artifacts/test.sh &
 res=0 && wait $! || res=$?
@@ -205,8 +214,8 @@ if [ x"$res" = x"0" ]; then
 	assert git merge-base --is-ancestor $last_good $bad_rev
 	cat > $artifacts/trigger-bisect <<EOF
 current_project=$current_project
-baseline_rev=$baseline_rev
-bad_rev=$last_good
+baseline_branch=$baseline_rev
+bad_branch=$last_good
 EOF
 	# Don't send any emails.
 	echo > $artifacts/jenkins/mail-recipients.txt