[PATCH 1/4] dg-extract-results.{sh, py}: Optionally read file list from stdin/file

[Pedro Alves <pedro@palves.net>]

dg-extract-results.sh and dg-extract-results.py take the summary/log
files to combine as command-line arguments, one argument per file.

That is fine for GCC, whose parallel harness produces one .sum per
target variant -- a handful of files.

GDB uses these scripts too, but its parallel harness writes one .sum
(and one .log) per test script, of which there are 2657 at the moment.

On Windows, with native Windows python, passing that many sum or log
files to dg-extract-results overflows the command-line length limit
(~32 KB), and the combine step dies:

 $ make check -j$(nproc)
 ...
 make[1]: Leaving directory '/c/msys2/home/alves/gdb/build-testsuite-windows'
 /c/gdb/src/gdb/testsuite/../../contrib/dg-extract-results.sh: line 39: /ucrt64/bin/python3: Argument list too long
 /c/gdb/src/gdb/testsuite/../../contrib/dg-extract-results.sh: line 39: /ucrt64/bin/python3: Argument list too long
 make: *** [Makefile:274: check-parallel] Error 2
 ...
 $ find outputs/ -name gdb.sum | wc -l
 2657

The .sh wrapper re-execs the faster Python implementation, forwarding
the file list, so the overflow can also surface at the re-exec.

Fix it by teaching both dg-extract-results.sh and
dg-extract-results.py a new -f option that reads the list of files to
process, one per line, from a named file, or from standard input when
the argument is "-".  The option may be given more than once and mixed
with file arguments.

A caller can then pipe the file list straight in via "-f -" instead of
expanding it onto the command line, so the length limit no longer
applies regardless of the host or Python flavor.

Existing callers can continue working as they were if they want, as
passing the file list as one file per argument is still supported.

Change-Id: Iaced5ba228972ce267f355de65fe5ad8a1e38c68
---
 contrib/dg-extract-results.py | 30 ++++++++++++++++++++++++++----
 contrib/dg-extract-results.sh | 17 +++++++++++++++--
 2 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/contrib/dg-extract-results.py b/contrib/dg-extract-results.py
index 98b0f4989c9..b5d890f6406 100644
--- a/contrib/dg-extract-results.py
+++ b/contrib/dg-extract-results.py
@@ -164,7 +164,7 @@ class Prog:
     def usage (self):
         name = sys.argv[0]
         sys.stderr.write ('Usage: ' + name
-                          + ''' [-t tool] [-l variant-list] [-L] log-or-sum-file ...
+                          + ''' [-t tool] [-l variant-list] [-L] [-f list-file] log-or-sum-file ...
 
     tool           The tool (e.g. g++, libffi) for which to create a
                    new test summary file.  If not specified then output
@@ -174,6 +174,12 @@ class Prog:
                    variants in the files for <tool>.
     sum-file       A test summary file with the format of those
                    created by runtest from DejaGnu.
+    list-file      A file listing the log-or-sum files to process, one
+                   per line.  Use "-" to read the list from standard
+                   input.  This avoids the command-line length limit
+                   when combining very many files.  May be given more
+                   than once, and may be mixed with log-or-sum-file
+                   arguments.
     If -L is used, merge *.log files instead of *.sum.  In this
     mode the exact order of lines may not be preserved, just different
     Running *.exp chunks should be in correct order.
@@ -189,19 +195,35 @@ class Prog:
     # Parse the command-line arguments.
     def parse_cmdline (self):
         try:
-            (options, self.files) = getopt.getopt (sys.argv[1:], 'l:t:L')
-            if len (self.files) == 0:
-                self.usage()
+            (options, self.files) = getopt.getopt (sys.argv[1:], 'l:t:Lf:')
             for (option, value) in options:
                 if option == '-l':
                     self.variations.append (value)
                 elif option == '-t':
                     self.tools.append (value)
+                elif option == '-f':
+                    self.read_file_list (value)
                 else:
                     self.do_sum = False
+            if len (self.files) == 0:
+                self.usage()
         except getopt.GetoptError as e:
             self.fatal (None, e.msg)
 
+    # Append the files listed in FILENAME, one per line, to self.files.
+    # FILENAME of "-" means read the list from standard input.  Blank
+    # lines are ignored.
+    def read_file_list (self, filename):
+        f = sys.stdin if filename == '-' else open (filename, 'r')
+        try:
+            for line in f:
+                line = line.strip()
+                if line:
+                    self.files.append (line)
+        finally:
+            if f is not sys.stdin:
+                f.close()
+
     # Try to parse time string TIME, returning an arbitrary time on failure.
     # Getting this right is just a nice-to-have so failures should be silent.
     def parse_time (self, time):
diff --git a/contrib/dg-extract-results.sh b/contrib/dg-extract-results.sh
index d64ba255838..d03e1a9b4e1 100755
--- a/contrib/dg-extract-results.sh
+++ b/contrib/dg-extract-results.sh
@@ -42,7 +42,7 @@ done
 
 usage() {
   cat <<EOF >&2
-Usage: $PROGNAME [-t tool] [-l variant-list] [-L] sum-file ...
+Usage: $PROGNAME [-t tool] [-l variant-list] [-L] [-f list-file] sum-file ...
 
     tool           The tool (e.g. g++, libffi) for which to create a
                    new test summary file.  If not specified then all
@@ -52,6 +52,11 @@ Usage: $PROGNAME [-t tool] [-l variant-list] [-L] sum-file ...
                    variants in the files for <tool>.
     sum-file       A test summary file with the format of those
                    created by runtest from DejaGnu.
+    list-file      A file listing the sum-files to process, one per line.
+                   Use "-" to read the list from standard input.  This
+                   avoids the command-line length limit when combining
+                   very many files.  May be given more than once, and
+                   may be mixed with sum-file arguments.
     If -L is used, merge *.log files instead of *.sum.  In this
     mode the exact order of lines may not be preserved, just different
     Running *.exp chunks should be in correct order.
@@ -69,18 +74,26 @@ msg() {
 VARIANTS=""
 TOOL=""
 MODE="sum"
+LIST_FILES=""
 
-while getopts "l:t:L" ARG; do
+while getopts "l:t:Lf:" ARG; do
   case $ARG in
   l)  VARIANTS="${VARIANTS} ${OPTARG}";;
   t)  test -z "$TOOL" || (msg "${PROGNAME}: only one tool can be specified"; exit 1);
       TOOL="${OPTARG}";;
   L)  MODE="log";;
+  f)  if test "${OPTARG}" = "-" ; then
+        LIST_FILES="${LIST_FILES} `cat`"
+      else
+        LIST_FILES="${LIST_FILES} `cat "${OPTARG}"`"
+      fi;;
   \?) usage; exit 0;;
   esac
 done
 shift `expr ${OPTIND} - 1`
 
+set -- ${LIST_FILES} "$@"
+
 if test $# -lt 1 ; then
   usage
   exit 1
-- 
2.54.0