[update_(llc_)test_checks.py] Support pre-processing commands

This has been rather useful in our downstream CHERI target where we want
to run tests both with addrspace(0) and addrspace(200) pointers.
With this patch we can prefix the opt command with
`sed -e 's/addrspace(200)/addrspace(0)/g' -e 's/-A200-P200-G200//g'` to
test both cases using the same IR input.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D95137

1 files changed, 14 insertions, 1 deletions

diff --git a/llvm/utils/UpdateTestChecks/common.py b/llvm/utils/UpdateTestChecks/common.py
index 4598475..449ccb0 100644
--- a/llvm/utils/UpdateTestChecks/common.py
+++ b/llvm/utils/UpdateTestChecks/common.py
@@ -2,6 +2,7 @@ from __future__ import print_function
 
 import copy
 import glob
+import os
 import re
 import subprocess
 import sys
@@ -141,11 +142,23 @@ def should_add_line_to_output(input_line, prefix_set, skip_global_checks = False
   return True
 
 # Invoke the tool that is being tested.
-def invoke_tool(exe, cmd_args, ir):
+def invoke_tool(exe, cmd_args, ir, preprocess_cmd=None, verbose=False):
   with open(ir) as ir_file:
     # TODO Remove the str form which is used by update_test_checks.py and
     # update_llc_test_checks.py
     # The safer list form is used by update_cc_test_checks.py
+    if preprocess_cmd:
+      # Allow pre-processing the IR file (e.g. using sed):
+      assert isinstance(preprocess_cmd, str)  # TODO: use a list instead of using shell
+      preprocess_cmd = preprocess_cmd.replace('%s', ir).strip()
+      if verbose:
+        print('Pre-processing input file: ', ir, " with command '",
+              preprocess_cmd, "'", sep="", file=sys.stderr)
+      # Python 2.7 doesn't have subprocess.DEVNULL:
+      with open(os.devnull, 'w') as devnull:
+        pp = subprocess.Popen(preprocess_cmd, shell=True, stdin=devnull,
+                              stdout=subprocess.PIPE)
+        ir_file = pp.stdout
     if isinstance(cmd_args, list):
       stdout = subprocess.check_output([exe] + cmd_args, stdin=ir_file)
     else: