C++11 constexpr: Add note stacks containing backtraces if constant evaluation
fails within a call to a constexpr function. Add -fconstexpr-backtrace-limit
argument to driver and frontend, to control the maximum number of notes so
produced (default 10). Fix APValue printing to be able to pretty-print all
APValue types, and move the testing for this functionality from a unittest to
a -verify test now that it's visible in clang's output.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146749 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/constexpr-printing.cpp b/test/SemaCXX/constexpr-printing.cpp
new file mode 100644
index 0000000..341495c
--- /dev/null
+++ b/test/SemaCXX/constexpr-printing.cpp
@@ -0,0 +1,73 @@
+// RUN: %clang_cc1 %s -std=c++11 -fsyntax-only -verify
+
+constexpr int extract(struct S &s);
+
+struct S {
+ constexpr S() : n(extract(*this)), m(0) {}
+ constexpr S(int k) : n(k), m(extract(*this)) {}
+ int n, m;
+};
+
+constexpr int extract(S &s) { return s.n; }
+
+// FIXME: once we produce notes for constexpr variable declarations, this should
+// produce a note indicating that S.n is used uninitialized.
+constexpr S s1; // expected-error {{constant expression}}
+constexpr S s2(10);
+
+typedef __attribute__((vector_size(16))) int vector_int;
+
+struct T {
+ constexpr T() : arr() {}
+ int arr[4];
+};
+struct U : T {
+ constexpr U(const int *p) : T(), another(), p(p) {}
+ constexpr U(const U &u) : T(), another(), p(u.p) {}
+ T another;
+ const int *p;
+};
+constexpr U u1(&u1.arr[2]);
+
+constexpr int test_printing(int a, float b, _Complex int c, _Complex float d,
+ int *e, int &f, vector_int g, U h) {
+ return *e; // expected-note {{subexpression}}
+}
+U u2(0);
+static_assert(test_printing(12, 39.762, 3 + 4i, 12.9 + 3.6i, &u2.arr[4], u2.another.arr[2], (vector_int){5, 1, 2, 3}, u1) == 0, ""); // \
+expected-error {{constant expression}} \
+expected-note {{in call to 'test_printing(12, 3.976200e+01, 3+4i, 1.290000e+01+3.600000e+00i, &u2.T::arr[4], u2.another.arr[2], {5, 1, 2, 3}, {{{}}, {{}}, &u1.T::arr[2]})'}}
+
+struct V {
+ // FIXME: when we can generate these as constexpr constructors, remove the
+ // explicit definitions.
+ constexpr V() : arr{[255] = 42} {}
+ constexpr V(const V &v) : arr{[255] = 42} {}
+ int arr[256];
+};
+constexpr V v;
+constexpr int get(const int *p) { return *p; } // expected-note {{subexpression}}
+constexpr int passLargeArray(V v) { return get(v.arr+256); } // expected-note {{in call to 'get(&v.arr[256])'}}
+static_assert(passLargeArray(v) == 0, ""); // expected-error {{constant expression}} expected-note {{in call to 'passLargeArray({{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...}})'}}
+
+union Union {
+ constexpr Union(int n) : b(n) {}
+ constexpr Union(const Union &u) : b(u.b) {}
+ int a, b;
+};
+constexpr Union myUnion = 76;
+
+constexpr int badness(Union u) { return u.a + u.b; } // expected-note {{subexpression}}
+static_assert(badness(myUnion), ""); // expected-error {{constant expression}} \
+ expected-note {{in call to 'badness({.b = 76})'}}
+
+struct MemPtrTest {
+ int n;
+ void f();
+};
+MemPtrTest mpt;
+constexpr int MemPtr(int (MemPtrTest::*a), void (MemPtrTest::*b)(), int &c) {
+ return c; // expected-note {{subexpression}}
+}
+static_assert(MemPtr(&MemPtrTest::n, &MemPtrTest::f, mpt.*&MemPtrTest::n), ""); // expected-error {{constant expression}} \
+expected-note {{in call to 'MemPtr(&MemPtrTest::n, &MemPtrTest::f, mpt.n)'}}