Implement support for operator overloading using candidate operator
functions for built-in operators, e.g., the builtin
bool operator==(int const*, int const*)
can be used for the expression "x1 == x2" given:
struct X {
operator int const*();
} x1, x2;
The scheme for handling these built-in operators is relatively simple:
for each candidate required by the standard, create a special kind of
candidate function for the built-in. If overload resolution picks the
built-in operator, we perform the appropriate conversions on the
arguments and then let the normal built-in operator take care of it.
There may be some optimization opportunity left: if we can reduce the
number of built-in operator overloads we generate, overload resolution
for these cases will go faster. However, one must be careful when
doing this: GCC generates too few operator overloads in our little
test program, and fails to compile it because none of the overloads it
generates match.
Note that we only support operator overload for non-member binary
operators at the moment. The other operators will follow.
As part of this change, ImplicitCastExpr can now be an lvalue.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@59148 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/overloaded-builtin-operators.cpp b/test/SemaCXX/overloaded-builtin-operators.cpp
new file mode 100644
index 0000000..aabe8dd
--- /dev/null
+++ b/test/SemaCXX/overloaded-builtin-operators.cpp
@@ -0,0 +1,66 @@
+// RUN: clang -fsyntax-only -verify %s
+struct yes;
+struct no;
+
+struct Short {
+ operator short();
+};
+
+struct Long {
+ operator long();
+};
+
+yes& islong(long);
+no& islong(int);
+
+void f(Short s, Long l) {
+ // C++ [over.built]p12
+ (void)static_cast<yes&>(islong(s + l));
+ (void)static_cast<no&>(islong(s + s));
+
+ // C++ [over.built]p17
+ (void)static_cast<yes&>(islong(s % l));
+ (void)static_cast<yes&>(islong(l << s));
+ (void)static_cast<no&>(islong(s << l));
+}
+
+struct ShortRef {
+ operator short&();
+};
+
+struct LongRef {
+ operator volatile long&();
+};
+
+void g(ShortRef sr, LongRef lr) {
+ // C++ [over.built]p18
+ short& sr1 = (sr *= lr);
+ volatile long& lr1 = (lr *= sr);
+
+ // C++ [over.built]p22
+ short& sr2 = (sr %= lr);
+ volatile long& lr2 = (lr <<= sr);
+
+ bool b1 = (sr && lr) || (sr || lr);
+}
+
+struct VolatileIntPtr {
+ operator int volatile *();
+};
+
+struct ConstIntPtr {
+ operator int const *();
+};
+
+void test_with_ptrs(VolatileIntPtr vip, ConstIntPtr cip, ShortRef sr) {
+#if 0
+ // FIXME: Enable these tests once we have operator overloading for
+ // operator[].
+ const int& cir1 = cip[sr];
+ const int& cir2 = sr[cip];
+ volatile int& vir1 = vip[sr];
+ volatile int& vir2 = sr[vip];
+#endif
+ bool b1 = (vip == cip);
+ long p1 = vip - cip;
+}