Bench: analyze failures just after fallback

benching/tools/errors.sh

@@ -41,6 +41,16 @@ function count_fallbacks_failed {
     cat $TMP_FILE | grep -c "step:.* dwarf_step also failed"
 }
 
+function count_fail_after_fallback_to_dwarf {
+    cat $TMP_FILE \
+        | "$(dirname $0)/line_patterns.py" \
+            "fallback with" \
+            "step:.* unw_step called" \
+            ~"step:.* unw_step called" \
+            "step:.* returning -" \
+        | grep Complete -c
+}
+
 function report {
     flavour="$1"
 
@@ -53,12 +63,14 @@ function report {
     if [ "$flavour" = "eh_elf" ]; then
         fallbacks=$(count_eh_fallbacks)
         fallbacks_to_dwarf=$(count_fallbacks_to_dwarf)
+        fallbacks_to_dwarf_failed_after=$(count_fail_after_fallback_to_dwarf)
         fallbacks_failed=$(count_fallbacks_failed)
         fallbacks_to_heuristics="$(( $fallbacks \
             - $fallbacks_to_dwarf \
             - $fallbacks_failed))"
         echo -e "* success:\t\t\t\t$successes"
         echo -e "* fallback to DWARF:\t\t\t$fallbacks_to_dwarf"
+        echo -e "* …of which failed at next step:\t$fallbacks_to_dwarf_failed_after"
         echo -e "* fallback to libunwind heuristics:\t$fallbacks_to_heuristics"
         computed_sum=$(( $successes + $fallbacks - $fallbacks_failed + $failures ))
     else

benching/tools/line_patterns.py

@@ -0,0 +1,69 @@
+#!/usr/bin/env python3
+
+import sys
+import re
+
+
+class Match:
+    def __init__(self, re_str, negate=False):
+        self.re = re.compile(re_str)
+        self.negate = negate
+
+    def matches(self, line):
+        return self.re.search(line) is not None
+
+
+class Matcher:
+    def __init__(self, match_objs):
+        self.match_objs = match_objs
+        self.match_pos = 0
+        self.matches = 0
+
+        if not self.match_objs:
+            raise Exception("No match expressions provided")
+        if self.match_objs[-1].negate:
+            raise Exception("The last match object must be a positive expression")
+
+    def feed(self, line):
+        for cur_pos, exp in enumerate(self.match_objs[self.match_pos :]):
+            cur_pos = cur_pos + self.match_pos
+            if not exp.negate:  # Stops the for here, whether matching or not
+                if exp.matches(line):
+                    self.match_pos = cur_pos + 1
+                    print(
+                        "Passing positive {}, advance to {}".format(
+                            cur_pos, self.match_pos
+                        )
+                    )
+                    if self.match_pos >= len(self.match_objs):
+                        print("> Complete match, reset.")
+                        self.matches += 1
+                        self.match_pos = 0
+                return
+            else:
+                if exp.matches(line):
+                    print("Failing negative [{}] {}, reset".format(exp.negate, cur_pos))
+                    old_match_pos = self.match_pos
+                    self.match_pos = 0
+                    if old_match_pos != 0:
+                        print("> Refeed: ", end="")
+                        self.feed(line)
+                    return
+
+
+def get_args(args):
+    out_args = []
+    for arg in args:
+        negate = False
+        if arg[0] == "~":
+            negate = True
+            arg = arg[1:]
+        out_args.append(Match(arg, negate))
+    return out_args
+
+
+if __name__ == "__main__":
+    matcher = Matcher(get_args(sys.argv[1:]))
+    for line in sys.stdin:
+        matcher.feed(line)
+    print(matcher.matches)