Basic code generation support for std::initializer_list.

We now generate temporary arrays to back std::initializer_list objects
initialized with braces. The initializer_list is then made to point at
the array. We support both ptr+size and start+end forms, although
the latter is untested.

Array lifetime is correct for temporary std::initializer_lists (e.g.
call arguments) and local variables. It is untested for new expressions
and member initializers.

Things left to do:
Massively increase the amount of testing. I need to write tests for
start+end init lists, temporary objects created as a side effect of
initializing init list objects, new expressions, member initialization,
creation of temporary objects (e.g. std::vector) for initializer lists,
and probably more.
Get lifetime "right" for member initializers and new expressions. Not
that either are very useful.
Implement list-initialization of array new expressions.

llvm-svn: 150803

1 files changed, 80 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp b/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp
new file mode 100644
index 0000000..ef7af88
--- /dev/null
+++ b/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp
@@ -0,0 +1,80 @@
+// RUN: %clang_cc1 -std=c++11 -S -emit-llvm -o - %s | FileCheck %s
+
+namespace std {
+  typedef decltype(sizeof(int)) size_t;
+
+  // libc++'s implementation
+  template <class _E>
+  class initializer_list
+  {
+    const _E* __begin_;
+    size_t    __size_;
+
+    initializer_list(const _E* __b, size_t __s)
+      : __begin_(__b),
+        __size_(__s)
+    {}
+
+  public:
+    typedef _E        value_type;
+    typedef const _E& reference;
+    typedef const _E& const_reference;
+    typedef size_t    size_type;
+
+    typedef const _E* iterator;
+    typedef const _E* const_iterator;
+
+    initializer_list() : __begin_(nullptr), __size_(0) {}
+
+    size_t    size()  const {return __size_;}
+    const _E* begin() const {return __begin_;}
+    const _E* end()   const {return __begin_ + __size_;}
+  };
+}
+
+void fn1(int i) {
+  // CHECK: define void @_Z3fn1i
+  // temporary array
+  // CHECK: [[array:%[^ ]+]] = alloca [3 x i32]
+  // CHECK: getelementptr inbounds [3 x i32]* [[array]], i{{32|64}} 0
+  // CHECK-NEXT: store i32 1, i32*
+  // CHECK-NEXT: getelementptr
+  // CHECK-NEXT: store
+  // CHECK-NEXT: getelementptr
+  // CHECK-NEXT: load
+  // CHECK-NEXT: store
+  // init the list
+  // CHECK-NEXT: getelementptr
+  // CHECK-NEXT: getelementptr inbounds [3 x i32]*
+  // CHECK-NEXT: store i32*
+  // CHECK-NEXT: getelementptr
+  // CHECK-NEXT: store i{{32|64}} 3
+  std::initializer_list<int> intlist{1, 2, i};
+}
+
+struct destroyme1 {
+  ~destroyme1();
+};
+struct destroyme2 {
+  ~destroyme2();
+};
+
+
+void fn2() {
+  // CHECK: define void @_Z3fn2v
+  void target(std::initializer_list<destroyme1>);
+  // objects should be destroyed before dm2, after call returns
+  target({ destroyme1(), destroyme1() });
+  // CHECK: call void @_ZN10destroyme1D1Ev
+  destroyme2 dm2;
+  // CHECK: call void @_ZN10destroyme2D1Ev
+}
+
+void fn3() {
+  // CHECK: define void @_Z3fn3v
+  // objects should be destroyed after dm2
+  auto list = { destroyme1(), destroyme1() };
+  destroyme2 dm2;
+  // CHECK: call void @_ZN10destroyme2D1Ev
+  // CHECK: call void @_ZN10destroyme1D1Ev
+}