[llvm-commits] [llvm] r134398 - /llvm/trunk/include/llvm/Support/CFG.h

[Tobias Grosser]

Author: grosser
Date: Mon Jul  4 18:09:02 2011
New Revision: 134398

URL: http://llvm.org/viewvc/llvm-project?rev=134398&view=rev
Log:
SuccIterator on bbs without terminator insts

Remove the assert that triggers if SuccIterator is constructed for a basic block
without a terminator instruction. Instead of triggering an assert a succ_end()
iterator is returned. This models a basic block with zero successors and allows
us to use F->viewCFG() on incompletely constructed functions.

Modified:
    llvm/trunk/include/llvm/Support/CFG.h

Modified: llvm/trunk/include/llvm/Support/CFG.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/CFG.h?rev=134398&r1=134397&r2=134398&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/CFG.h (original)
+++ llvm/trunk/include/llvm/Support/CFG.h Mon Jul  4 18:09:02 2011
@@ -109,11 +109,18 @@
   // TODO: This can be random access iterator, only operator[] missing.
 
   explicit inline SuccIterator(Term_ T) : Term(T), idx(0) {// begin iterator
-    assert(T && "getTerminator returned null!");
   }
   inline SuccIterator(Term_ T, bool)                       // end iterator
-    : Term(T), idx(Term->getNumSuccessors()) {
-    assert(T && "getTerminator returned null!");
+    : Term(T) {
+    if (Term)
+      idx = Term->getNumSuccessors();
+    else
+      // Term == NULL happens, if a basic block is not fully constructed and
+      // consequently getTerminator() returns NULL. In this case we construct a
+      // SuccIterator which describes a basic block that has zero successors.
+      // Defining SuccIterator for incomplete and malformed CFGs is especially
+      // useful for debugging.
+      idx = 0;
   }
 
   inline const Self &operator=(const Self &I) {
@@ -201,6 +208,7 @@
 
   /// Get the source BB of this iterator.
   inline BB_ *getSource() {
+    assert(Term && "Source not available, if basic block was malformed");
     return Term->getParent();
   }
 };