Fix TestRegisterVariables.py on Windows

Use __attribute__((regparm(x))) to ensure the compiler enregisters at least some arguments when calling functions.

Differential Revision: http://reviews.llvm.org/D19548

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@267616 91177308-0d34-0410-b5e6-96231b3b80d8

packages/Python/lldbsuite/test/lang/c/register_variables/test.c

@@ -5,20 +5,20 @@ struct bar {
   int m2;
 };
 
-void f1(int a, struct bar *b) __attribute__ ((noinline));
+void f1(int a, struct bar *b) __attribute__((noinline)) __attribute__((regparm(2)));
 void f1(int a, struct bar *b)
 {
   b->m2 = b->m1 + a; // set breakpoint here
 }
 
-void f2(struct bar *b) __attribute__ ((noinline));
+void f2(struct bar *b) __attribute__((noinline)) __attribute__((regparm(1)));
 void f2(struct bar *b)
 {
   int c = b->m2;
   printf("%d\n", c); // set breakpoint here
 }
 
-float f3() __attribute__ ((noinline));
+float f3() __attribute__((noinline));
 float f3() {
   return 3.14f;
 }