Add polly support to sort_includes.py

Changes:
 -  Add "isl/" as a system library prefix. Even though isl is regularly
    imported into polly, it is still used like an external library.
 -  Add "json/" as a system library prefix. Polly uses json-cpp as external
    library.
 -  Distinguish between llvm and subproject libraries. Always sort subprojects
    before LLVM. This was already the case with clang, as 'clang' comes before
    'llvm', but we also want 'polly' to be sorted before 'llvm'.

The sorting of headers that are not part of Polly or isl remains unchanged.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236929 91177308-0d34-0410-b5e6-96231b3b80d8

utils/sort_includes.py

@@ -29,7 +29,8 @@ def sort_includes(f):
   headers_end = 0
   api_headers = []
   local_headers = []
-  project_headers = []
+  subproject_headers = []
+  llvm_headers = []
   system_headers = []
   for (i, l) in enumerate(lines):
     if l.strip() == '':
@@ -44,12 +45,16 @@ def sort_includes(f):
         api_headers.append(header)
         look_for_api_header = False
         continue
-      if header.startswith('<') or header.startswith('"gtest/'):
+      if (header.startswith('<') or header.startswith('"gtest/') or
+          header.startswith('"isl/') or header.startswith('"json/')):
         system_headers.append(header)
         continue
-      if (header.startswith('"llvm/') or header.startswith('"llvm-c/') or
-          header.startswith('"clang/') or header.startswith('"clang-c/')):
-        project_headers.append(header)
+      if (header.startswith('"clang/') or header.startswith('"clang-c/') or
+          header.startswith('"polly/')):
+        subproject_headers.append(header)
+        continue
+      if (header.startswith('"llvm/') or header.startswith('"llvm-c/')):
+        llvm_headers.append(header)
         continue
       local_headers.append(header)
       continue
@@ -65,9 +70,10 @@ def sort_includes(f):
     return
 
   local_headers = sorted(set(local_headers))
-  project_headers = sorted(set(project_headers))
+  subproject_headers = sorted(set(subproject_headers))
+  llvm_headers = sorted(set(llvm_headers))
   system_headers = sorted(set(system_headers))
-  headers = api_headers + local_headers + project_headers + system_headers
+  headers = api_headers + local_headers + subproject_headers + llvm_headers + system_headers
   header_lines = ['#include ' + h for h in headers]
   lines = lines[:headers_begin] + header_lines + lines[headers_end + 1:]