[utils] Add minimal support for MIR inputs to update_llc_test_checks.py

update_{llc,mir}_test_checks.py applicability is determined by the
output (assembly or MIR), not the input, which makes
update_llc_test_checks.py the right tool to generate tests that start at
MIR and stop at the final assembly.

This commit adds the minimal support for this path. Main limitation that
remains:

- MIR has to have LLVM IR section, and the CHECK lines will be inserted
  into the LLVM IR functions that correspond to the MIR functions.

Running
  ../utils/update_llc_test_checks.py --llc-binary ./bin/llc
on a slightly modified  ../test/CodeGen/X86/bad-tls-fold.mir

produces the following diff:

+# NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+# RUN: llc %s -o - | FileCheck %s
 --- |
   target triple = "x86_64-unknown-linux-gnu"

@@ -6,17 +7,31 @@
   @i = external thread_local global i32

   define i32 @or() {
+  ; CHECK-LABEL: or:
+  ; CHECK:       # %bb.0: # %entry
+  ; CHECK-NEXT:    movq {{.*}}(%rip), %rax
+  ; CHECK-NEXT:    orq $7, %rax
+  ; CHECK-NEXT:    movq i@{{.*}}(%rip), %rcx
+  ; CHECK-NEXT:    orq %rax, %rcx
+  ; CHECK-NEXT:    movl %fs:(%rcx), %eax
+  ; CHECK-NEXT:    retq
   entry:
     ret i32 undef
   }
-
   define i32 @and() {
+  ; CHECK-LABEL: and:
+  ; CHECK:       # %bb.0: # %entry
+  ; CHECK-NEXT:    movq {{.*}}(%rip), %rax
+  ; CHECK-NEXT:    orq $7, %rax
+  ; CHECK-NEXT:    movq i@{{.*}}(%rip), %rcx
+  ; CHECK-NEXT:    andq %rax, %rcx
+  ; CHECK-NEXT:    movl %fs:(%rcx), %eax
+  ; CHECK-NEXT:    retq
   entry:
     ret i32 undef
   }
 ...

(not applied)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372277 91177308-0d34-0410-b5e6-96231b3b80d8

utils/update_llc_test_checks.py

@@ -19,7 +19,7 @@ import re
 
 from UpdateTestChecks import asm, common
 
-ADVERT = '; NOTE: Assertions have been autogenerated by '
+ADVERT = ' NOTE: Assertions have been autogenerated by '
 
 
 def main():
@@ -44,7 +44,6 @@ def main():
   args = parser.parse_args()
 
   script_name = os.path.basename(__file__)
-  autogenerated_note = (ADVERT + 'utils/' + script_name)
 
   test_paths = [test for pattern in args.tests for test in glob.glob(pattern)]
   for test in test_paths:
@@ -118,6 +117,13 @@ def main():
 
       llc_cmd_args = llc_cmd[len(llc_tool):].strip()
       llc_cmd_args = llc_cmd_args.replace('< %s', '').replace('%s', '').strip()
+      if test.endswith('.mir'):
+        llc_cmd_args += ' -x mir'
+        comment_sym = '#'
+        check_indent = '  '
+      else:
+        comment_sym = ';'
+        check_indent = ''
 
       check_prefixes = [item for m in common.CHECK_PREFIX_RE.finditer(filecheck_cmd)
                                for item in m.group(1).split(',')]
@@ -128,6 +134,8 @@ def main():
       # now, we just ignore all but the last.
       run_list.append((check_prefixes, llc_cmd_args, triple_in_cmd, march_in_cmd))
 
+    autogenerated_note = (comment_sym + ADVERT + 'utils/' + script_name)
+
     func_dict = {}
     for p in run_list:
       prefixes = p[0]
@@ -166,7 +174,7 @@ def main():
             continue
 
         # Print out the various check lines here.
-        asm.add_asm_checks(output_lines, ';', run_list, func_dict, func_name)
+        asm.add_asm_checks(output_lines, check_indent + ';', run_list, func_dict, func_name)
         is_in_function_start = False
 
       if is_in_function:
@@ -180,7 +188,7 @@ def main():
         continue
 
       # Discard any previous script advertising.
-      if input_line.startswith(ADVERT):
+      if input_line.startswith(comment_sym + ADVERT):
         continue
 
       # If it's outside a function, it just gets copied to the output.