Fix crasher in RewriteObjC::RewriteObjCSynchronizedStmt(). Can't depend on the source locations of the sync expression (since it may have been rewritten.

Fixes <rdar://problem/6156363> clang ObjC rewriter: rewriting attached file causes assertion failure: invalid FileID


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@54986 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 11 insertions, 5 deletions

diff --git a/Driver/RewriteObjC.cpp b/Driver/RewriteObjC.cpp
index 8de2c0a693..36e973d723 100644
--- a/Driver/RewriteObjC.cpp
+++ b/Driver/RewriteObjC.cpp
@@ -1304,11 +1304,13 @@ Stmt *RewriteObjC::RewriteObjCSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
   std::string buf; 
   buf = "objc_sync_enter";
   ReplaceText(startLoc, 13, buf.c_str(), buf.size());
-  SourceLocation endLoc = S->getSynchExpr()->getLocEnd();
+  // We can't use S->getSynchExpr()->getLocEnd() to find the end location, since 
+  // the sync expression is typically a message expression that's already 
+  // been rewritten! (which implies the SourceLocation's are invalid).
+  SourceLocation endLoc = S->getSynchBody()->getLocStart();
   const char *endBuf = SM->getCharacterData(endLoc);
-  endBuf++;
-  const char *rparenBuf = strchr(endBuf, ')');
-  SourceLocation rparenLoc = startLoc.getFileLocWithOffset(rparenBuf-startBuf);
+  while (*endBuf != ')') endBuf--;
+  SourceLocation rparenLoc = startLoc.getFileLocWithOffset(endBuf-startBuf);
   buf = ");\n";
   // declare a new scope with two variables, _stack and _rethrow.
   buf += "/* @try scope begin */ \n{ struct _objc_exception_data {\n";
@@ -1321,7 +1323,7 @@ Stmt *RewriteObjC::RewriteObjCSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
   startLoc = S->getSynchBody()->getLocEnd();
   startBuf = SM->getCharacterData(startLoc);
   
-  assert((*startBuf == '}') && "bogus @try block");
+  assert((*startBuf == '}') && "bogus @synchronized block");
   SourceLocation lastCurlyLoc = startLoc;
   buf = "}\nelse {\n";
   buf += "  _rethrow = objc_exception_extract(&_stack);\n";
diff --git a/test/Rewriter/objc-synchronized-1.m b/test/Rewriter/objc-synchronized-1.m
index c2aa348654..5f8ae31d5d 100644
--- a/test/Rewriter/objc-synchronized-1.m
+++ b/test/Rewriter/objc-synchronized-1.m
@@ -13,4 +13,8 @@ void foo(id sem)
     return;
   }
  SYNC_AFTER();
+ @synchronized ([sem self]) {
+    SYNCH_BODY();
+    return;
+ }
 }