Index: llvm/utils/git-svn/git-llvm
===================================================================
--- llvm/utils/git-svn/git-llvm
+++ llvm/utils/git-svn/git-llvm
@@ -44,9 +44,11 @@
     # Python 2
     from pipes import quote
 
+LLVM_MONOREPO_DIR = '/trunk'
+
 # It's *almost* a straightforward mapping from the monorepo to svn...
 LLVM_MONOREPO_SVN_MAPPING = {
-    d: (d + '/trunk')
+    d: (d + LLVM_MONOREPO_DIR)
     for d in [
         'clang-tools-extra',
         'compiler-rt',
@@ -67,10 +69,10 @@
         'pstl',
     ]
 }
-LLVM_MONOREPO_SVN_MAPPING.update({'clang': 'cfe/trunk'})
-LLVM_MONOREPO_SVN_MAPPING.update({'': 'monorepo-root/trunk'})
+LLVM_MONOREPO_SVN_MAPPING.update({'clang': 'cfe' + LLVM_MONOREPO_DIR})
+LLVM_MONOREPO_SVN_MAPPING.update({'': 'monorepo-root' + LLVM_MONOREPO_DIR})
 
-SPLIT_REPO_NAMES = {'llvm-' + d: d + '/trunk'
+SPLIT_REPO_NAMES = {'llvm-' + d: d + LLVM_MONOREPO_DIR
                     for d in ['www', 'zorg', 'test-suite', 'lnt']}
 
 VERBOSE = False
@@ -430,6 +432,11 @@
     Note: a current limitation is that git does not track file rename, so they
     will show up in SVN as delete+add.
     '''
+
+    # Check for the branch.
+    if LLVM_MONOREPO_DIR != '/trunk' and not args.force_branch:
+        die("Branch is not trunk (specify --force-branch to override)")
+
     # Get the git root
     git_root = git('rev-parse', '--show-toplevel')
     if not os.path.isdir(git_root):
@@ -543,6 +550,10 @@
     populates the git commit message with both the SVN revision and git hash of
     the change being reverted.'''
 
+    # Check for the branch.
+    if LLVM_MONOREPO_DIR != '/trunk' and not args.force_branch:
+        die("Branch is not trunk (specify --force-branch to override)")
+
     # Get the git root
     git_root = git('rev-parse', '--show-toplevel')
     if not os.path.isdir(git_root):
@@ -626,6 +637,11 @@
         help='Do everything other than commit to svn.  Leaves junk in the svn '
         'repo, so probably will not work well if you try to commit more '
         'than one rev.')
+    parser_push.add_argument(
+        '--force-branch',
+        dest='force_branch',
+        action='store_true',
+        help='Force pushing to a non-trunk branch.')
     parser_push.add_argument(
         'rev_range',
         metavar='GIT_REVS',
@@ -651,6 +667,11 @@
         action='store_true',
         help='Do everything other than perform a revert. Prints the git '
         'revert command it would have run.')
+    parser_revert.add_argument(
+        '--force-branch',
+        dest='force_branch',
+        action='store_true',
+        help='Force reverting a commit on a non-trunk branch.')
     parser_revert.set_defaults(func=cmd_revert)
 
     parser_svn_lookup = subcommands.add_parser(