build: ABI: add stgdiff reporting

This change adds stgdiff reports alongside the existing abidiff
reports.

Bug: 201642997
Change-Id: I43191ac60d68712aafcdeed317e9936517d5598b
Signed-off-by: Giuliano Procida <gprocida@google.com>

3 files changed, 51 insertions, 2 deletions

diff --git a/abi/abitool.py b/abi/abitool.py
index bf933fb0..a787a8f3 100644
--- a/abi/abitool.py
+++ b/abi/abitool.py
@@ -146,7 +146,8 @@ class AbiTool(object):
             vmlinux_path=None):
         raise NotImplementedError()
 
-    def diff_abi(self, old_dump, new_dump, diff_report, short_report, symbol_list):
+    def diff_abi(self, old_dump, new_dump, diff_report, short_report,
+                 symbol_list, full_report):
         raise NotImplementedError()
 
     def name(self):
@@ -233,9 +234,42 @@ class Libabigail(AbiTool):
 
         return abi_changed
 
+class Stg(AbiTool):
+    DIFF_ERROR                   = (1<<0)
+    DIFF_ABI_CHANGE              = (1<<2)
+
+    """" Concrete AbiTool implementation for STG """
+    def dump_kernel_abi(self, linux_tree, dump_path, symbol_list,
+            vmlinux_path=None):
+        raise
+
+    def diff_abi(self, old_dump, new_dump, diff_report, short_report=None,
+                 symbol_list=None, full_report=None):
+        # shoehorn the interface
+        basename = diff_report
+
+        log.info(f"stgdiff {old_dump} {new_dump} at {basename}.*")
+        command = ["stgdiff", "--abi", old_dump, new_dump]
+        for f in ["plain", "flat", "small", "viz"]:
+            command.extend(["--format", f, "--output", f"{basename}.{f}"])
+
+        abi_changed = False
+
+        with open(f"{basename}.errors", "w") as out:
+            try:
+                subprocess.check_call(command, stdout=out, stderr=out)
+            except subprocess.CalledProcessError as e:
+                if e.returncode & self.DIFF_ERROR:
+                    raise
+                abi_changed = True
+
+        return abi_changed
+
 def get_abi_tool(abi_tool = "libabigail"):
+    log.info(f"using {abi_tool} for abi analysis")
     if abi_tool == "libabigail":
-        log.info("using libabigail for abi analysis")
         return Libabigail()
+    if abi_tool == "STG":
+        return Stg()
 
     raise ValueError("not a valid abi_tool: %s" % abi_tool)
diff --git a/build-tools/path/linux-x86/stgdiff b/build-tools/path/linux-x86/stgdiff
new file mode 120000
index 00000000..d50da5b6
--- /dev/null
+++ b/build-tools/path/linux-x86/stgdiff
@@ -0,0 +1 @@
+../../../../prebuilts/kernel-build-tools/linux-x86/bin/stgdiff
\ No newline at end of file
diff --git a/build_abi.sh b/build_abi.sh
index c5887878..cb3bcd5d 100755
--- a/build_abi.sh
+++ b/build_abi.sh
@@ -343,6 +343,20 @@ if [ -n "$ABI_DEFINITION" ]; then
             echo "========================================================" 1>&2
             cat ${abi_report}.short 1>&2
         fi
+
+        set +e
+        ${ROOT_DIR}/build/abi/diff_abi --abi-tool STG                         \
+                                       --baseline $KERNEL_DIR/$ABI_DEFINITION \
+                                       --new      ${DIST_DIR}/${abi_out_file} \
+                                       --report   ${abi_report}.stg
+        rc=$?
+        set -e
+        echo "========================================================"
+        echo " stgdiff reports have been created at ${abi_report}.stg.*"
+
+        if [ $rc -ne 0 ]; then
+            echo " stgdiff has reported ABI differences" 1>&2
+        fi
     fi
     if [ $UPDATE -eq 1 ] ; then
         echo "========================================================"