llvm-c: Return NULL from LLVMGetFirstTarget instead of asserting

If no targets are registered, LLVMGetFirstTarget currently fails with
an assertion. This patch makes it return NULL instead, similarly to
how LLVMGetNextTarget would.

Patch by Peter Zotov

Differential Revision: http://llvm-reviews.chandlerc.com/D1908

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192878 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/TargetMachineC.cpp b/lib/Target/TargetMachineC.cpp
index 741912200da14fef70d4d421f5809e99beb3de88..9fccfcd9e22517c265b6f7e791d99223ed4ecb2b 100644 (file)
--- a/lib/Target/TargetMachineC.cpp
+++ b/lib/Target/TargetMachineC.cpp
@@ -60,8 +60,12 @@ inline LLVMTargetRef wrap(const Target * P) {
 }
 
 LLVMTargetRef LLVMGetFirstTarget() {
-   const Target* target = &*TargetRegistry::begin();
-   return wrap(target);
+  if(TargetRegistry::begin() == TargetRegistry::end()) {
+    return NULL;
+  }
+
+  const Target* target = &*TargetRegistry::begin();
+  return wrap(target);
 }
 LLVMTargetRef LLVMGetNextTarget(LLVMTargetRef T) {
   return wrap(unwrap(T)->getNext());