[ORC-RT] Add string_view and span utilities for use by the ORC runtime.

These are substitutes for std::string_view (and llvm::StringRef) and std::span
(and llvm::ArrayRef) for use by the ORC runtime.

compiler-rt/lib/orc/adt.h

@@ -0,0 +1,98 @@
+//===----------------------- adt.h - Handy ADTs -----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of the ORC runtime support library.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ORC_RT_ADT_H
+#define ORC_RT_ADT_H
+
+#include <cstring>
+#include <limits>
+#include <string>
+
+namespace __orc_rt {
+
+constexpr std::size_t dynamic_extent = std::numeric_limits<std::size_t>::max();
+
+/// A substitute for std::span (and llvm::ArrayRef).
+/// FIXME: Remove in favor of std::span once we can use c++20.
+template <typename T, std::size_t Extent = dynamic_extent> class span {
+public:
+  typedef T element_type;
+  typedef std::remove_cv<T> value_type;
+  typedef std::size_t size_type;
+  typedef std::ptrdiff_t difference_type;
+  typedef T *pointer;
+  typedef const T *const_pointer;
+  typedef T &reference;
+  typedef const T &const_reference;
+
+  typedef pointer iterator;
+
+  static constexpr std::size_t extent = Extent;
+
+  constexpr span() noexcept = default;
+  constexpr span(T *first, size_type count) noexcept
+      : Data(first), Size(count) {}
+
+  template <std::size_t N>
+  constexpr span(T (&arr)[N]) noexcept : Data(&arr[0]), Size(N) {}
+
+  constexpr iterator begin() const noexcept { return Data; }
+  constexpr iterator end() const noexcept { return Data + Size; }
+  constexpr pointer data() const noexcept { return Data; }
+  constexpr reference operator[](size_type idx) const { return Data[idx]; }
+  constexpr size_type size() const noexcept { return Size; }
+  constexpr bool empty() const noexcept { return Size == 0; }
+
+private:
+  T *Data = nullptr;
+  size_type Size = 0;
+};
+
+/// A substitue for std::string_view (and llvm::StringRef).
+/// FIXME: Remove in favor of std::string_view once we have c++17.
+class string_view {
+public:
+  typedef char value_type;
+  typedef char *pointer;
+  typedef const char *const_pointer;
+  typedef char &reference;
+  typedef const char &const_reference;
+  typedef std::size_t size_type;
+  typedef std::ptrdiff_t difference_type;
+
+  typedef const_pointer const_iterator;
+  typedef const_iterator iterator;
+
+  constexpr string_view() noexcept = default;
+  constexpr string_view(const char *S, size_type Count)
+      : Data(S), Size(Count) {}
+  string_view(const char *S) : Data(S), Size(strlen(S)) {}
+
+  constexpr const_iterator begin() const noexcept { return Data; }
+  constexpr const_iterator end() const noexcept { return Data + Size; }
+  constexpr const_pointer data() const noexcept { return Data; }
+  constexpr const_reference operator[](size_type idx) { return Data[idx]; }
+  constexpr size_type size() const noexcept { return Size; }
+  constexpr bool empty() const noexcept { return Size == 0; }
+
+private:
+  const char *Data = nullptr;
+  size_type Size = 0;
+};
+
+inline std::string to_string(string_view SV) {
+  return std::string(SV.data(), SV.size());
+}
+
+} // end namespace __orc_rt
+
+#endif // ORC_RT_COMMON_H

compiler-rt/lib/orc/unittests/CMakeLists.txt

@@ -80,6 +80,7 @@ macro(add_orc_unittest testname)
 endmacro()
 
 set(UNITTEST_SOURCES
+  adt_test.cpp
   error_test.cpp
   extensible_rtti_test.cpp
   orc_unit_test_main.cpp

compiler-rt/lib/orc/unittests/adt_test.cpp

@@ -0,0 +1,80 @@
+//===-- adt_test.cpp ------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of the ORC runtime.
+//
+//===----------------------------------------------------------------------===//
+
+#include "adt.h"
+#include "gtest/gtest.h"
+
+using namespace __orc_rt;
+
+TEST(ADTTest, SpanDefaultConstruction) {
+  span<int> S;
+  EXPECT_TRUE(S.empty()) << "Default constructed span not empty";
+  EXPECT_EQ(S.size(), 0U) << "Default constructed span size not zero";
+  EXPECT_EQ(S.begin(), S.end()) << "Default constructed span begin != end";
+}
+
+TEST(ADTTest, SpanConstructFromFixedArray) {
+  int A[] = {1, 2, 3, 4, 5};
+  span<int> S(A);
+  EXPECT_FALSE(S.empty()) << "Span should be non-empty";
+  EXPECT_EQ(S.size(), 5U) << "Span has unexpected size";
+  EXPECT_EQ(std::distance(S.begin(), S.end()), 5U)
+      << "Unexpected iterator range size";
+  EXPECT_EQ(S.data(), &A[0]) << "Span data has unexpected value";
+  for (unsigned I = 0; I != S.size(); ++I)
+    EXPECT_EQ(S[I], A[I]) << "Unexpected span element value";
+}
+
+TEST(ADTTest, SpanConstructFromIteratorAndSize) {
+  int A[] = {1, 2, 3, 4, 5};
+  span<int> S(&A[0], 5);
+  EXPECT_FALSE(S.empty()) << "Span should be non-empty";
+  EXPECT_EQ(S.size(), 5U) << "Span has unexpected size";
+  EXPECT_EQ(std::distance(S.begin(), S.end()), 5U)
+      << "Unexpected iterator range size";
+  EXPECT_EQ(S.data(), &A[0]) << "Span data has unexpected value";
+  for (unsigned I = 0; I != S.size(); ++I)
+    EXPECT_EQ(S[I], A[I]) << "Unexpected span element value";
+}
+
+TEST(ADTTest, StringViewDefaultConstruction) {
+  string_view S;
+  EXPECT_TRUE(S.empty()) << "Default constructed span not empty";
+  EXPECT_EQ(S.size(), 0U) << "Default constructed span size not zero";
+  EXPECT_EQ(S.begin(), S.end()) << "Default constructed span begin != end";
+}
+
+TEST(ADTTest, StringViewConstructFromCharPtrAndSize) {
+  const char *Str = "abcdefg";
+  string_view S(Str, 5);
+  EXPECT_FALSE(S.empty()) << "Span should be non-empty";
+  EXPECT_EQ(S.size(), 5U) << "Span has unexpected size";
+  EXPECT_EQ(std::distance(S.begin(), S.end()), 5U)
+      << "Unexpected iterator range size";
+  EXPECT_EQ(S.data(), &Str[0]) << "Span data has unexpected value";
+  for (unsigned I = 0; I != S.size(); ++I)
+    EXPECT_EQ(S[I], Str[I]) << "Unexpected span element value";
+}
+
+TEST(ADTTest, StringViewConstructFromCharPtr) {
+  const char *Str = "abcdefg";
+  size_t StrLen = strlen(Str);
+  string_view S(Str);
+
+  EXPECT_FALSE(S.empty()) << "Span should be non-empty";
+  EXPECT_EQ(S.size(), StrLen) << "Span has unexpected size";
+  EXPECT_EQ(std::distance(S.begin(), S.end()), StrLen)
+      << "Unexpected iterator range size";
+  EXPECT_EQ(S.data(), &Str[0]) << "Span data has unexpected value";
+  for (unsigned I = 0; I != S.size(); ++I)
+    EXPECT_EQ(S[I], Str[I]) << "Unexpected span element value";
+}