Coverage: remove function signature lines that are never report as hit

.jenkinsci-new/build.groovy

@@ -58,7 +58,8 @@ def initialCoverage(String buildDir) {
 
 def postCoverage(buildDir, String cobertura_bin) {
   sh "cmake --build ${buildDir} --target coverage.info"
-  sh "python ${cobertura_bin} ${buildDir}/reports/coverage.info -o ${buildDir}/reports/coverage.xml"
+  sh "python .jenkinsci-new/helpers/remove-function-lines.py ${buildDir}/reports/coverage.info ${buildDir}/reports/cleaned-coverage.info"
+  sh "python ${cobertura_bin} ${buildDir}/reports/cleaned-coverage.info -o ${buildDir}/reports/coverage.xml"
   cobertura autoUpdateHealth: false, autoUpdateStability: false,
     coberturaReportFile: "**/${buildDir}/reports/coverage.xml", conditionalCoverageTargets: '75, 50, 0',
     failUnhealthy: false, failUnstable: false, lineCoverageTargets: '75, 50, 0', maxNumberOfBuilds: 50,

.jenkinsci-new/helpers/remove-function-lines.py

@@ -0,0 +1,48 @@
+#!/usr/bin/env python3
+
+# https://github.com/JeremyAgost/lcov-llvm-function-mishit-filter
+# https://github.com/linux-test-project/lcov/issues/30
+
+import argparse
+import subprocess
+
+def demangle(symbol):
+    p = subprocess.Popen(['c++filt','-n'], stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+    return p.communicate(input=symbol.encode())[0].decode().strip()
+
+def filter_lcov(lines, verbose=False):
+    defs, srcfile = {}, ''
+    for line in lines:
+        if line.startswith('SF:'):
+            defs = {}
+            srcfile = line[3:].strip()
+        elif line.startswith('end_of_record'):
+            defs = {}
+        elif line.startswith('FN:'):
+            lineno, symbol = line[3:].split(',')
+            if verbose:
+                defs[lineno] = demangle(symbol)
+            else:
+                defs[lineno] = True
+        elif line.startswith('DA:'):
+            lineno = line[3:].split(',')[0]
+            if lineno in defs:
+                if verbose:
+                    printf('Ignoring: {srcfile}:{lineno}:{defs[lineno]}')
+                continue
+        yield line
+
+def main():
+    p = argparse.ArgumentParser()
+    p.add_argument('input', type=str)
+    p.add_argument('output', type=str)
+    p.add_argument('--verbose', '-v', action='store_true')
+    args = p.parse_args()
+    with open(args.input, 'r') as fin:
+        lines = list(fin)
+    with open(args.output, 'w') as fout:
+        for line in filter_lcov(lines, verbose=args.verbose):
+            fout.write(line)
+
+if __name__ == '__main__':
+    main()