[Clang Interpreter] Initial patch for the constexpr interpreter

Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.

Reviewers: Bigcheese, jfb, rsmith

Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64146

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@370839 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 119 deletions

diff --git a/test/SemaCXX/constant-expression-cxx2a.cpp b/test/SemaCXX/constant-expression-cxx2a.cpp
index dba877ff21..cc6b196048 100644
--- a/test/SemaCXX/constant-expression-cxx2a.cpp
+++ b/test/SemaCXX/constant-expression-cxx2a.cpp
@@ -414,125 +414,6 @@ namespace TypeId {
   static_assert(side_effects());
 }
 
-namespace Union {
-  struct Base {
-    int y; // expected-note {{here}}
-  };
-  struct A : Base {
-    int x;
-    int arr[3];
-    union { int p, q; };
-  };
-  union B {
-    A a;
-    int b;
-  };
-  constexpr int read_wrong_member() { // expected-error {{never produces a constant}}
-    B b = {.b = 1};
-    return b.a.x; // expected-note {{read of member 'a' of union with active member 'b'}}
-  }
-  constexpr int change_member() {
-    B b = {.b = 1};
-    b.a.x = 1;
-    return b.a.x;
-  }
-  static_assert(change_member() == 1);
-  constexpr int change_member_then_read_wrong_member() { // expected-error {{never produces a constant}}
-    B b = {.b = 1};
-    b.a.x = 1;
-    return b.b; // expected-note {{read of member 'b' of union with active member 'a'}}
-  }
-  constexpr int read_wrong_member_indirect() { // expected-error {{never produces a constant}}
-    B b = {.b = 1};
-    int *p = &b.a.y;
-    return *p; // expected-note {{read of member 'a' of union with active member 'b'}}
-  }
-  constexpr int read_uninitialized() {
-    B b = {.b = 1};
-    int *p = &b.a.y;
-    b.a.x = 1;
-    return *p; // expected-note {{read of uninitialized object}}
-  }
-  static_assert(read_uninitialized() == 0); // expected-error {{constant}} expected-note {{in call}}
-  constexpr void write_wrong_member_indirect() { // expected-error {{never produces a constant}}
-    B b = {.b = 1};
-    int *p = &b.a.y;
-    *p = 1; // expected-note {{assignment to member 'a' of union with active member 'b'}}
-  }
-  constexpr int write_uninitialized() {
-    B b = {.b = 1};
-    int *p = &b.a.y;
-    b.a.x = 1;
-    *p = 1;
-    return *p;
-  }
-  static_assert(write_uninitialized() == 1);
-  constexpr int change_member_indirectly() {
-    B b = {.b = 1};
-    b.a.arr[1] = 1;
-    int &r = b.a.y;
-    r = 123;
-
-    b.b = 2;
-    b.a.y = 3;
-    b.a.arr[2] = 4;
-    return b.a.arr[2];
-  }
-  static_assert(change_member_indirectly() == 4);
-  constexpr B return_uninit() {
-    B b = {.b = 1};
-    b.a.x = 2;
-    return b;
-  }
-  constexpr B uninit = return_uninit(); // expected-error {{constant expression}} expected-note {{subobject of type 'int' is not initialized}}
-  static_assert(return_uninit().a.x == 2);
-  constexpr A return_uninit_struct() {
-    B b = {.b = 1};
-    b.a.x = 2;
-    return b.a;
-  }
-  // FIXME: It's unclear that this should be valid. Copying a B involves
-  // copying the object representation of the union, but copying an A invokes a
-  // copy constructor that copies the object elementwise, and reading from
-  // b.a.y is undefined.
-  static_assert(return_uninit_struct().x == 2);
-  constexpr B return_init_all() {
-    B b = {.b = 1};
-    b.a.x = 2;
-    b.a.y = 3;
-    b.a.arr[0] = 4;
-    b.a.arr[1] = 5;
-    b.a.arr[2] = 6;
-    return b;
-  }
-  static_assert(return_init_all().a.x == 2);
-  static_assert(return_init_all().a.y == 3);
-  static_assert(return_init_all().a.arr[0] == 4);
-  static_assert(return_init_all().a.arr[1] == 5);
-  static_assert(return_init_all().a.arr[2] == 6);
-  static_assert(return_init_all().a.p == 7); // expected-error {{}} expected-note {{read of member 'p' of union with no active member}}
-  static_assert(return_init_all().a.q == 8); // expected-error {{}} expected-note {{read of member 'q' of union with no active member}}
-  constexpr B init_all = return_init_all();
-
-  constexpr bool test_no_member_change =  []{
-    union U { char dummy = {}; };
-    U u1;
-    U u2;
-    u1 = u2;
-    return true;
-  }();
-
-  struct S1 {
-    int n;
-  };
-  struct S2 : S1 {};
-  struct S3 : S2 {};
-  void f() {
-    S3 s;
-    s.n = 0;
-  }
-}
-
 namespace TwosComplementShifts {
   using uint32 = __UINT32_TYPE__;
   using int32 = __INT32_TYPE__;