FileCheck Enhancement - repeats in regular expressions

[eklepilkina]

Summary

Repeat with current number should become available by using {n}, {n,m} , {,n}, {n,}

[jyknight]

utils/FileCheck/FileCheck.cpp

240

Comment for what this is doing (skipping to the end of a sequence of consecutive }s.)

254

Putting this in FileCheck is a bad hack. It is the wrong place to make a regexp syntax change.

Either users can simply use {0,N}, or we could change our regexp implementation to support {,N}.

[eklepilkina]

utils/FileCheck/FileCheck.cpp

254

Ok, I'll remove this and it will be able to use only {0,n} in such cases. In my opinion, it's a great idea to change regexp library, because current library is quite old and has unsupported useful regexp features.

test/FileCheck/repeat-in-regex.txt

+// RUN: FileCheck -input-file %s %s
+
+text to be matchedmatchedmatchedmatchedmatched
+// CHECK: {{(matched){5}}}
+
+r1, is register is register is register is register is register
+// CHECK: [[REG:r[0-9]{1,2}]]
+// CHECK-SAME: {{(is register ){1,}}}
+
+r2r13r1
+dag
+// CHECK-DAG: {{dag{1}}}
+// CHECK-DAG: {{[[REG]]{0,2}}}

utils/FileCheck/FileCheck.cpp

         return true;
       }
 
+      // Find end of pattern in case of quantifiers of the form {n,m} 
+      size_t NextChar = End + 2;
+      while (NextChar < PatternStr.size() && PatternStr[NextChar] == '}') {
+        NextChar++;
+      }
+
+      End = NextChar - 2;
+
       // Enclose {{}} patterns in parens just like [[]] even though we're not
       // capturing the result for any purpose.  This is required in case the
       // expression contains an alternation like: CHECK:  abc{{x|z}}def.  We